We present a comprehensive study of axion-like particles (ALPs) in meson decays, combining effective field theory and ultraviolet models within the open-source tool ALPaca. The analysis accounts for running and matching effects across energy scales, including non-perturbative QCD corrections via chiral perturbation theory. We discuss several benchmark models, both flavour-universal and non-universal, using the most up-to-date theoretical computations for ALP decays and branching ratios. Experimental signatures such as prompt, displaced, and invisible decays are included. A dedicated analysis of the Belle II anomaly in the decay $B^+ \to K^+ \nu \bar{\nu}$ is performed. Our results highlight the power of flavour observables in constraining ALPs and provide a versatile foundation for future searches.

We present a systematic functional approach to calculating symmetry-restoring counterterms in Effective Field Theories (EFTs) regulated using the Breitenlohner--Maison--'t Hooft--Veltman (BMHV) scheme. Building on a recently developed method that employs auxiliary spurion fields, our approach automates the extraction of these counterterms directly from the one-loop effective action, offering a streamlined and efficient procedure. We demonstrate its efficacy by applying it to the Standard Model Effective Field Theory (SMEFT) at dimension six, providing the first complete determination of its symmetry-restoring counterterms in the BMHV scheme. Our work establishes a robust foundation for consistent one-loop matching and two-loop running computations in EFTs with chiral gauge symmetries.

Motivated by the recent observation of the open-charm tetraquark $T_{c\bar{s}0}^{a}(2327)$ by the LHCb Collaboration, as well as results from Lattice QCD calculations, we consider the $T_{c\bar{s}0}^{a}(2327)$ and the $D_{s0}^{*}(2317)$ as $DK$ molecular states, with $I(J^{P})$ equal to $1(0^{+})$ and $0(0^{+})$, respectively, and we investigate their strong decay behavior in an effective Lagrangian approach. Within the model parameter range, we can reproduce the $T_{c\bar{s}0}^{a}(2327)$ experimental decay width, with the assumption that the $D_{s}^{+}\pi^{0}$ is the dominant decay channel of the $T_{c\bar{s}0}^{a+}(2327)$. In the same parameter range, we can establish a stringent limitation for the decay width of the $D_{s0}^{*}(2317)$, which is $(63.0-209)~\mathrm{keV}$ being significantly smaller than the PDG upper limit value.

This paper investigates the physics potential of the proton-proton Future Circular Collider (FCC-hh) in the search for a new heavy gauge boson, Z', within the framework of the minimal Baryon-Lepton (B-L) symmetric model. We examine the exclusion limits on the mass of the Z' boson for various sets of coupling constants, utilizing leptonic decays, specifically into charged lepton pairs (electron and muon). Using the DARKCAST framework, we compare the parameter constraints derived from previous experiments with the expected reach of the FCC-hh, providing insights into the collider sensitivity and potential to probe new physics beyond the Standard Model.

Instead of the glueball-$\eta'$ mixing ansatz, the latest measured ratios of the branching fractions of $B_{(s)}^0\to J/\psi \eta^{(\prime)}$ decays by LHCb can be understood by including the contribution from the light quark annihilation effect enhanced by the QCD $\mathrm{U}_A(1)$ anomaly for light pseudoscalar mesons.

In this work we study the isospin-violating decays of $B_{c}(1P)^{+}\to B_{c}^{(*)+}\pi^{0}$, which may provide additional information for the determination of the properties of the first orbital excitation states of $B_{c}(1P)^{+}$. By assuming a dual relation between the U(1) anomaly soft-gluon coupling for $B_{c}(1P)^{+}\to B_{c}^{(*)+}\pi^{0}$ and the intermediate meson loop transitions, we can quantify the isospin-violating decay effects for these four $P$-wave states. We find that the partial decay width of $B_{c0}^{*+}\to B_{c}^{+}\pi^{0}$ is about three orders of magnitude larger than that for $B_{c2}^{*+}\to B_{c}^{+}\pi^{0}$. It implies that $B_{c0}^{*+}$ can be established in the $B_{c}^{+}\pi^{0}$ decay channel as a single state. Meanwhile, the two axial-vector states $B_{c1}^{+}/B_{c1}'^{+}$ can be possibly identified in $B_{c1}^{+}/B_{c1}'^{+}\to B_{c}^{*+}\pi^{0}$ with comparable strengths. Although these isospin-violating decays turn out to be small, the theoretical predictions should be useful for guiding future experimental efforts.

The gauge field theory of the standard electroweak model in the presence of the electroweak bubble wall is investigated, with an eye toward its applications to microscopic phenomena which are supposed to have occurred during the phase transition in the early universe. The asymptotic fields are defined anew so that the effects of the position-dependent Higgs condensate are taken into account through the position-dependent $W$ and $Z$ boson masses. A novel method of massive gauge field quantization in the $R_{\xi}$-gauge with $\xi =1$ is proposed for the case of the position-dependent masses. Our method is based on the eigenfunction expansion method associated with second-order differential operators, i.e., a sort of generalized Fourier this http URL commutation relations of creation and annihilation operators of various wave propagation modes are given in terms of the so-called spectral function. The decoupling of unphysical states from the physical S-matrix is also investigated along the line of Kugo-Ojima's quartet mechanism on the basis of the BRST symmetry. It is pointed out that one of the quartet fields is not merely the unphysical scalar field but should be a linear combination of the unphysical scalar and the gauge fields. The physical and unphysical polarizations of the gauge field waves are unambiguously distinguished and this will help us evaluate the friction caused by the physical polarization states of $W$ and $Z$ boson waves on the bubble wall during the phase transition in the early universe.

We study dynamical properties of strongly coupled chiral matter by using holographic method. We demonstrate, at both linear and nonlinear levels, that perturbations on thermodynamically unstable backgrounds within the spinodal region of chiral first-order phase transitions exhibit dynamic instability. The corresponding magnitude of dynamic instability can be characterized by the critical momentum. Furthermore, we found that, within a certain temperature range, the quasi-normal mode spectrum contains purely imaginary diffusive modes. As spatial momentum increases, a transition occurs in the system's long-time dynamics. The dominant contribution shifts from diffusive mode to propagating mode. When the diffusive mode becomes dominant, the spectral function exhibits a transport peak structure in the low-frequency region. A heuristic argument suggests that this particular transition can be related to the chiral symmetry breaking and restoration.

The effect of meson-exchange currents on charged-current quasielastic neutrino scattering with single-nucleon emission is computed and analyzed within the relativistic Fermi gas model. This contribution arises primarily from the interference between one-body and two-body currents, where the two-body operator excites a 1p1h state in the presence of a second, spectator nucleon. The results obtained show a reduction of the vector, axial and vector-axial transverse response functions and, consequently, a decrease in the total neutrino cross section. In addition to a comparison with the non-relativistic limit, other models are also explored, such as the relativistic mean field model for nuclear matter and the superscaling analysis with relativistic effective mass, both of which yield qualitatively similar results.

Determining the transport properties of Quark-Gluon Plasma is one of the most important aspects of relativistic heavy ion collision studies. Field-theoretical calculations of the transport coefficients such as the shear and bulk viscosities require Kubo formulae which in turn require real-time correlation functions of stress-energy tensors. Consequently, knowing the analytic structure of these correlation functions is essential in any such studies. Using the energy-conservation laws and the results from the gravity-hydrodynamics analysis, we determine the low-frequency and low-wavenumber analytic structures of all stress-energy correlation functions in the rest frame of the medium. By comparing with the diffusion and sound spectra from the second-order and the third-order relativistic hydrodynamics, various new Kubo formulae are derived in the limit where the zero-frequency limit is taken first. We also show that the meaning of the Kubo formulae for relaxation times can change when higher-order terms are added to hydrodynamics. A subtle issue of taking the zero frequency and zero wavenumber limits when using skeleton diagrams is addressed as well.

Based on a machine learning holographic QCD model, we construct a systematical framework to investigate the properties of the scalar glueballs continuously from zero temperature to finite temperature. By using both the quasi-normal frequencies and the spectral functions, we extract the pole masses, thermal widths, screening masses and dispersion relation of the scalar glueballs in hot medium. It is shown that the pole masses almost remain the vacuum values at temperatures far below the critical temperature $T_c$ , and then decrease with the increasing of temperature until a temperature lower than $T_c$. This result qualitatively agrees with earlier lattice simulations. While the pole masses increase monotonically above the critical temperature $T_c$, which agrees with recent lattice calculation. Meanwhile, it is shown that the thermal widths increase monotonically with temperature, which also agrees with the near $T_c$ lattice simulations. The screening mass exhibits a similar temperature-dependent behavior to the pole mass, while the dispersion relation increasingly deviates from the relativistic one as the temperature rises. It is interesting to note that we obtain the imaginary corrections in the thermal correlators, which contains both the temperal and spatial information and might be helpful for the four-dimensional calculations. Furthermore, by comparing the quasi-normal modes and the spectral functions, we note that it requires more careful analysis when applying the spectral functions in studying thermal hadrons from holography, since there could be other types of quasi-normal modes which are not related with bound states while they may contribute to the peaks of the spectral functions.

Within the framework of an equivparticle model employing mean-field approximation, we investigate systematically the mass spectra of color-singlet $N$-quark configurations with $N = 3, 6, 9, 12, 15$, and 18, which are assumed to be spherically symmetric with quarks occupying the 1s$_{1/2}$ state, i.e., compact multibaryon states. At a given quark number $N$, these states collectively form a single irreducible representation under SU(6) symmetry. Our analysis yields comprehensive mass formulae that characterize these SU(6) multiplets, providing a unified description of their mass spectra. In order to effectively constrain the parameter space of the model and improve the prediction accuracy, we carry out a Bayesian parameter inference based on the experimental masses of eight baryons and $D_{03}$. The posterior probability density functions and their correlations of the model parameters are examined, based on which we further predict the masses of various multibaryon states and provide their 68$\%$ and 90$\%$ credible intervals. In our prediction, H-dibaryon, $D_{03}$, and the dibaryon with $S = -6$ are all bound states relative to $\Lambda\Lambda$, $\Delta\Delta$ and $\Omega\Omega$ thresholds, while slight probabilities of other stable dibaryons (23.64$\%$ more stable than $\Omega^- \Xi^0$ for the state wtih $I = \frac{1}{2}$, $S = -5$ and 92.49$\%$ more stable than $\Xi^0\Xi^-$ for the state wtih $I = 0$, $S = -4$) and tribaryons (0.25$\%$ more stable than $\Xi^-\Xi^0\Xi^0$ for the state wtih $S = -6$, $I = 1/2$; 2.19$\%$ more stable than $\Lambda\Xi^0\Xi^-$ for the state wtih $S = -5$, $I = 0$; and 2.21$\%$ more stable than $\Lambda\Lambda\Xi^0$ for the state wtih $S = -4$, $I = 1/2$) are observed as well. For heavier compact multibaryon states, it is unlikely for them to be stable.

The $\kappa/K_0^*(700)$ meson remains the most elusive among the light scalar resonances, with its presence in weak decays obscured by limited precision in branching fraction measurements. As a result, the true nature of the $\kappa$ remains difficult to explore. Through a partial-wave analysis of the semileptonic decay $D^+ \to K^-\pi^+ e^+ \nu_e$, we extract ${\cal B}(D^+ \to \bar\kappa^0 e^+ \nu_e, \bar\kappa^0 \to K^-\pi^+) =(2.2 \pm 0.1) \times 10^{-3}$. Previously considered negligible, this contribution is now shown to dominate the observed s-wave branching fraction. This reveals that clear evidence for the $\kappa$ in weak decays has long existed, but was misidentified as part of the non-resonant background. The extracted $D^+ \to \bar\kappa^0$ form factor, $f^+(0) = 0.32 \pm 0.01$, is significantly smaller than the $q\bar q$ prediction of $0.82 \pm 0.05$, and closely aligns with the $q^2\bar q^2$ expectation of $0.36 \pm 0.02$. Notably, this finding supports a compact tetraquark interpretation of the $\kappa$ meson.

We have carried out an evaluation of the $\pi^+ \pi^-$ and $D_s^+ \pi^+$ mass distributions in the $D_{s1}(2536)$ decay to $D_s^+ \pi^+ \pi^-$, from the perspective that the $D_{s1}(2536)$ is a molecular state, mostly made from $DK^*$ in $I=0$. We are able to obtain, not only the mass distributions, but the branching ratio of this decay. The shape of the mass distributions differ appreciably from those of the analogous reaction $D_{s1}(2460)\to D_s^+ \pi^+ \pi^-$, which has been measured by the LHCb collaboration and analyzed theoretically from the perspective that the $D_{s1}(2460)$ is a molecular state of $D^*K$, showing a good agreement with the data. In spite of the analogy with the $D_{s1}(2460)$ decay, the dynamical differences in the decay mechanism are important, since now the $f_0(500)$ resonance is not generated, while it was the dominant mechanism in the $D_{s1}(2460)\to D_s^+ \pi^+ \pi^-$ decay. Nonetheless, we find striking differences in the mass distributions compared with phase space as a consequence of the decay mechanism. The branching ratio obtained is an order of magnitude bigger than the one of the $D_{s1}(2460)\to D_s^+ \pi^+ \pi^-$ reaction, mostly due to the larger available phase space. Hence, its measurement could be done, and it would shed light on the nature of the $D_{s1}(2536)$ resonance and indirectly on that of the $D_{s1}(2460)$.

The exclusive $J/\psi$ and $\Upsilon$ photoproduction in proton - proton ($pp$) and proton - lead ($pPb$) collisions at the LHC energies is investigated using the Generalized Parton Distribution (GDP) approach. Assuming the Goloskokov - Kroll (GK) model, we estimate the corresponding total cross - sections and rapidity distributions considering different parametrizations for the unpolarized gluon distribution of the proton. In particular, we compare the linear predictions, associated with DGLAP evolution, with those derived taking into account of the leading nonlinear corrections resulting from gluon recombination. The dependence of our predictions on the choice for the factorization scale is discussed.

NNLO QCD corrections for the pion electromagnetic form factor at large momentum transfer have been recently performed in [Phys. Rev. Lett. 132, 201901 (2024); Phys. Rev. Lett. 134, 221901 (2025)], revealing that the NLO and NNLO contributions are positive and sizeable. Unfortunately, these predictions have been obtained using the conventional scale-setting method and thus they are plagued by large renormalization scale ambiguities. In this paper, we analyze the pion electromagnetic form factor at NNLO by introducing the Principle of Maximum Conformality (PMC), a systematic method for eliminating renormalization scheme and scale ambiguities. By applying the PMC, a more precise perturbative QCD (pQCD) prediction for the pion EMFF $Q^2F_\pi(Q^2)$ without conventional renormalization scale ambiguity can be achieved. This improved pQCD prediction is highly beneficial for the precise determination of the pion light-cone distribution amplitude. We then conduct a comprehensive comparison between theoretical predictions and experimental measurements of the pion EMFF $Q^2F_\pi(Q^2)$.

Dark photons can be resonantly produced in the early universe via their coupling to an oscillating axion field. However, this mechanism typically requires large axion-dark photon couplings or some degree of fine-tuning. In this work, we present a new scenario in which efficient dark photon production arises from axion potentials that are shallower than quadratic at large field values. For moderately large initial misalignment angles, the oscillation of the axion field can trigger either efficient dark photon production or strong axion self-resonance via parametric resonance. When self-resonance dominates and disrupts the field's homogeneity, we show that oscillons -- localized, oscillating axion field configurations -- naturally form and can sustain continued dark photon production, provided the coupling is $\gtrsim \mathcal O(1)$. For dark photon mass up to three orders of magnitude below the axion mass, the produced dark photons can account for a significant fraction of the present-day dark matter. We support this scenario with numerical lattice simulations of a benchmark model. Our results further motivate experimental searches for ultralight dark photon dark matter. The simulation code is publicly available at this https URL.

The quarkonium production in association with a heavy-quark pair of the same flavor was found plays an important role in various production schemes, let alone it provides a distinctive signature that could be studied in experiment. Within the NRQCD framework, we perform the first complete calculation of the hadroproduction process $gg\to J/\psi+c\bar{c}$ at the next-to-leading order (NLO) in the expansion of strong coupling constant $\alpha_s$. The result tells that the NLO corrections substantially enhance the color-singlet yield and alter the predicted polarization patterns, and hence lead to a better agreement with experimental data across the $p_T$ spectrum. In contrast to charm-quark fragmentation, the $J/\psi$ and $c\bar{c}$ associated production channel displays a markedly different kinematic behavior, underscoring its distinct role in the production mechanism. While the inclusion of this process greatly reduces the discrepancy between color-singlet theoretical prediction and experimental measurement, a residual gap of approximately one order of magnitude still remains.

Large lepton flavor asymmetries with zero total lepton asymmetry could be generated in the Early Universe. They are loosely constrained by current observations, being washed out at MeV temperatures by neutrino oscillations. We show that such lepton flavor asymmetries open up a new parameter space for sterile neutrino dark matter, consistent with all observational bounds. To this end, we construct the semi-classical Boltzmann equation for sterile neutrinos applicable in the case of arbitrarily large lepton asymmetries, and confirm its validity by quantum kinetic equations. This way, we derive the maximal parameter space for sterile neutrino dark matter with lepton asymmetries. The allowed range of sterile neutrinos' squared couplings extends by up to two orders of magnitude across a 5-70 keV mass range, and may be testable by X-ray, structure formation, and upcoming CMB observations.

Within quantum electrodynamics we show that the Generalized Uncertainty Principle induces higher-derivative corrections that promote the topological invariant $F_{\mu\nu}\,\widetilde F^{\mu\nu}$ to the dynamical, non-topological operator $\partial^\lambda F_{\mu\nu}\,\partial_\lambda \widetilde F^{\mu\nu}$. We explore the resulting phenomenology, focusing on the generation of electric dipole moments. Our findings open a new low-energy window for testing quantum-gravity scenarios through precision measurements of charge-parity violation.

The strange pentaquarks with hidden heavy quark pair ($q^3c\bar c$ and $q^3b \bar b$) are investigated by the coupled-channel quark cluster model. Two types of the $q^3$ color-octet configurations are found to provide the attraction, which makes bound states, sharp resonances, and cusps in the baryon meson scattering. A resonance appears at around 4500 MeV in the strange hidden charm sector. Such structures are more clearly seen in the hidden bottom systems.

In this work, we study the charged-current (anti)neutrino-induced associated particle($K\Lambda$) production($\Delta S=0$) from free nucleons in the energy region of a few GeV, relevant to the (anti)neutrino oscillation experiments with accelerator and atmospheric neutrinos. We employ a model based on effective Lagrangians to evaluate the contributions from the nonresonant and the resonant diagrams. The nonresonant background terms are calculated using a microscopic model derived from the SU(3) chiral Lagrangians. For the resonant contributions, we consider the low-lying spin-$\frac{1}{2}$ resonances, such as $S_{11}(1650)$, $P_{11}(1710)$, $P_{11}(1880)$, and $S_{11}(1895)$, and spin-$\frac{3}{2}$ resonances, such as $P_{13}(1720)$ and $P_{13}(1900)$, which have finite branching ratios to the $K\Lambda$ channel. These resonant contributions are modelled using an effective phenomenological Lagrangian approach, with strong couplings determined from the experimental branching ratios and the decay widths to the $K\Lambda$ channel. To fix the parameters of the vector current interaction, the model is first used to reproduce satisfactorily the MAMI experimental data on the real photon induced scattering off the nucleon resulting an eta meson in the final state and with the CLAS data for the $K\Lambda$ production in the final state. The PCAC hypothesis and the generalized Goldberger-Treiman relation are used to fix the parameters of the axial vector interaction. The model is then applied to study the weak production of $K\Lambda$ induced by the neutrinos and antineutrinos, and predicts the numerical values for the $Q^2$-distribution, the kaon kinetic energy distribution, and the total scattering cross sections with and without a cut on the CM energy W. The results presented in this work are relevant for the present and future accelerator and atmospheric neutrino experiments.

We compute the two-loop contributions to Higgs production via gluon-gluon fusion ($gg \to h$) and Higgs decay into two photons ($h \to \gamma\gamma$), arising from third-generation four-quark operators in the Standard Model effective field theory (SMEFT). Our analysis is performed in the broken phase of the theory, retaining the full dependence on the Higgs and heavy-quark masses. This includes both finite matching corrections and logarithmic effects stemming from the renormalization group evolution within the SMEFT. As a byproduct, new two-loop anomalous dimensions in the SMEFT are obtained. We also briefly discuss the phenomenological implications of our two-loop calculations.

For more than twenty years, theory has failed to explain the pattern of the exotic heavy hadrons. We illustrate a simple solution to this longstanding puzzle using the Born-Oppenheimer approximation for QCD. Exotic hidden-heavy hadrons are bound states and resonances in potentials that are repulsive at short range and cross a heavy-hadron--pair threshold before approaching it. This explains the proximity of the exotic hidden-heavy hadrons to heavy-hadron--pair thresholds, identifies the thresholds that support bound states or resonances, and prevents an explosion in the number of predicted states. We also discuss the fine tunings of QCD that are responsible for the remarkable properties of some of the exotic hidden-heavy mesons.

Axion dark matter induces electromagnetic radiation in conductors through nearly perpetual oscillations of electrons, driven by axion-electron interactions through the so-called chiral magnetic effect. It therefore provides a complementary probe of the axion-electron coupling $g_{ae}$ beyond the conventional axion-photon coupling $g_{a \gamma}$ in cavities. We show that existing axion cavity experiments can constrain the coupling to $g_{ae}\lesssim 10^{-5}$ over the scanned axion mass ranges, $1\,\mu\, {\rm eV}\lesssim m_a\lesssim 20\,\mu\,{\rm eV}$. Although we find that the radiation due to $g_{ae}$ at the copper cavity surface of electric conductivity $\sigma$ is suppressed by $m_a^2/\sigma^2\sim 10^{-20}$, compared to the radiation inside the cavity by the axion-photon conversion due to $g_{a\gamma}$, a sensitivity of about $10^{-9}$ could be achieved for $g_{ae}$ over a wider range of $m_a$, including values higher than those previously probed, if copper walls are replaced with carbon-based conductors.

We investigate the effect of $R^2$ corrections on holographic complexity growth within the framework of the Complexity=Action(CA) conjecture. By introducing a probe string into Gauss-Bonnet(GB) $AdS$ black brane background, we analyze the time derivative of the Nambu-Goto(NG) action as the holographic dual to complexity growth. Our results indicate that the complexity growth is maximized for a stationary string and is suppressed by its motion. Significantly, we identify a crossover point at specific string velocity, where the influence of $R^2$ corrections on complexity growth changes. For slow strings, stronger $R^2$ corrections enhance complexity growth, whereas for fast strings they suppress it.

We explore a generative-model framework to infer the masses of heavy particles from detector-level data over a broad parameter space. Our model combines a transformer-based detector encoder and a diffusion neural network. We apply our model to a new physics scenario involving the pair production of wino-like chargino-neutralino, $pp \to \tilde\chi_1^{\pm} \tilde\chi_2^0$, in the $1\ell + 2\gamma + jets$ channel at the high luminosity LHC~(HL-LHC). We find that our framework can achieve mass reconstruction efficiency of $\gtrsim 70\%$ for the lightest neutralino $\tilde\chi_1^0$ and $\gtrsim 40\%$ for the second lightest neutralino $\tilde\chi_2^0$, for a mass tolerance of $\Delta m = 30~$GeV, across the entire parameter space accessible at the HL-LHC.

We present the calculation of complete next-to-leading order electroweak corrections to the Higgs boson production in $gg\to g H$ channel. We apply the method of differential equations combined with the selection of optimized master integrals to accomplish the calculation of master integrals. We consider three distinct $\alpha$ schemes. At leading order, the differential distributions and the total cross section differ among them. However, these discrepancies are considerably suppressed once electroweak corrections are taken into account. For $G_\mu$ scheme, the electroweak correction amounts to approximately $4.5\%$. Importantly, this correction exhibits non-trivial kinematic dependence.

In this work, we study the potential of analyzing the particular combination of $\kappa$ modifiers given by $\kappa_V^2-\kappa_{2V}$ to disentangle Beyond Standard Model Higgs signals in double Higgs production with two extra light jets at LHC. We use the Higgs Effective Field Theory approach, HEFT, for the gauge invariant description of these two $\kappa_V$ and $\kappa_{2V}$ parameters representing the BSM interactions of the Higgs particle with the electroweak gauge bosons, $HVV$ and $HHVV$ respectively. We illustrate the bonus of studying this particular combination $\kappa_V^2-\kappa_{2V}$ focusing in just one process, $HHjj$, instead of studying $\kappa_V$ and $\kappa_{2V}$ separately using various processes. For the detailed analysis here, we focus on the particular final state $H(\to \gamma \gamma) H (\to b \bar b)jj'$, with two photons, two b-jets and two light jets, which we analyze fully including parton showering, fragmentation, hadronization and detector effects, in both signal and main background. We find that the sensitivity to $\kappa_V^2-\kappa_{2V}$ could be notably improved at the HL-LHC by the proper cuts on the final state $b \bar b \gamma \gamma jj'$ that select optimally the events with VBF-topology and $HH$-topology. In particular, we propose strategies based on a good isolation of $\gamma \gamma$ and b-jet pairs, and focus specially on specific variables like $\eta_{\gamma \gamma}$ and $P^T_{\gamma \gamma}$ where the signal events distributions may discriminate efficiently between BSM signal versus SM background. We will show here how the high transversality of these two pairs in the signal (inherited from the high transversality of the $H$'s) is correlated with the non-vanishing value of this $(\kappa_V^2-\kappa_{2V})$ combination.

The CUDACPP plugin for MadGraph5_aMC@NLO aims to accelerate leading order tree-level event generation by providing the MadEvent event generator with data-parallel helicity amplitudes. These amplitudes are written in templated C++ and CUDA, allowing them to be compiled for CPUs supporting SSE4, AVX2, and AVX-512 instruction sets as well as CUDA- and HIP-enabled GPUs. Using SIMD instruction sets, CUDACPP-generated amplitudes are shown to speed up linearly with SIMD register size, and GPU offloading is shown to provide acceleration beyond that of SIMD instructions. Additionally, the resulting speed-up in event generation perfectly aligns with predictions from measured runtime fractions spent in amplitude routines, and proper GPU utilisation can speed up high-multiplicity QCD processes by an order of magnitude when compared to optimal CPU usage in server-grade CPUs.

We present the first fully nonlinear causality constraints in $D = 3 + 1$ dimensions for Israel-Stewart theory in the presence of energy and number diffusion in the Eckart and Landau hydrodynamic frames, respectively. These constraints are algebraic inequalities that make no assumption on the underlying geometry of the spacetime, or the equation of state. In order to highlight the distinct physical and structural behavior of the two hydrodynamic frames, we discuss the special ultrarelativistic ideal gas equation of state considered in earlier literature in $D = 1 + 1$ dimensions, and show that our general $D = 3 + 1$ constraints reduce to their results upon an appropriate choice of angles. For this equation of state in both $D = 1 + 1$ and $D = 3 + 1$ dimensions one can show that: (i) there exists a region allowed by nonlinear causality in which the baryon current transitions into a spacelike vector in the Landau frame, and (ii) an analogous argument shows that the solutions of the Eckart frame equations of motion never violate the dominant energy condition, assuming nonlinear causality holds. We then compare our results with those from linearized Israel-Stewart theory and show that the linear causality bounds fail to capture the new physical constraints on energy and number diffusion that are successfully obtained

In this work, we demonstrate that by treating space as a three dimensional elastic membrane, one can interpret the energy density stored in it as Dark Energy. In particular, we will model space as an infinitely large fundamental 3 brane and show that its vacuum stress energy tensor has the same mathematical form which one expects from the stress energy tensor describing a Lorentz invariant vacuum energy density (Dark Energy). We identify the dark-energy density with the tension of the fundamental 3 brane and thereby establish a direct correspondence between the cosmological constant and brane tension. Finally, we present a brief argument as to why the Cosmological Constant should be treated as a fundamental constant of nature, based on some light ontological discussion regarding the origin of the tension term in the broader framework of String Theory. In a forthcoming work, we will articulate a dynamical mechanism, which will be grounded in Q-theory, Hawking-Wu flux neutralization and broken super-symmetry, demonstrating the precise cancellation of vacuum energy in a manner such that the fundamental brane (spatial) tension remains the unique source of the Cosmological Constant.

We show that primordial black holes (PBHs) with significant spin and bulk motion produce sharply collimated neutrino bursts from Hawking evaporation, arising from the interplay of spin-induced angular anisotropy and relativistic Doppler boosting. This effect shifts the neutrino spectrum into the multi-GeV to hundreds of GeV range, where atmospheric backgrounds drop steeply, and enhances the flux by orders of magnitude within a narrow forward cone. We compute the full lab-frame neutrino distribution and derive updated constraints on PBH number density from non-observation of such bursts in IceCube and KM3NeT. Our results identify directional high-energy neutrino bursts as a distinctive, testable signature of spinning PBHs, providing a complementary probe of the PBH dark matter hypothesis and Hawking radiation.

The relative correlation between the magnitudes of elliptic flow ($v_2$) and triangular flow ($v_3$) has been accurately measured in nucleus-nucleus collisions at the LHC collider. As a function of the centrality of the collision, it changes sign and varies non-monotonically. We show that this is naturally explained by two combined effects. The first effect is a skewness in initial-state fluctuations, which is quantified by the correlation between the geometry-driven elliptic deformation in the reaction plane and the fluctuation-driven triangularity $\varepsilon_3$. We introduce an intensive measure of this skewness, which is generically of order unity and depends weakly on the system size and centrality. We evaluate its magnitude using Monte Carlo simulations of the initial state, which show that it is sensitive to the nucleon width. The second effect is the fluctuation of impact parameter relative to centrality classifiers used by experiment. The ATLAS collaboration uses two different centrality classifiers, the multiplicity $N_{ch}$ and the transverse energy $E_T$. We fit both sets of results for Pb+Pb collisions up to $\approx 40\%$ centrality with a single parameter, the intensive mixed skewness. Its value inferred from experiment agrees with theoretical expectations.

Recent observations have identified a significant 4.9$\sigma$ tension between the cosmic dipole inferred from galaxy number counts and that derived from the Cosmic Microwave Background (CMB), suggesting a potential deviation from the cosmological principle. This work investigates whether superhorizon isocurvature perturbations in cold dark matter (CDM) can account for this discrepancy. We demonstrate that, unlike adiabatic modes which cancel at leading order, superhorizon isocurvature modes can generate an intrinsic CMB dipole without significantly affecting galaxy number counts, thereby explaining the observed mismatch. We explore both single-mode and continuous-spectrum cases, focusing on two concrete models: a nearly scale-invariant power-law spectrum with a UV cutoff and axion-induced isocurvature perturbations. For the axion scenario, we show that if the radial mode evolves during inflation, the resulting perturbations can match the required amplitude while evading current CMB constraints. Our analysis constrains the self-coupling of associated potential for the axion to the range $10^{-9} < \lambda < 4 \times 10^{-9}$. These findings offer a viable solution to the dipole tension and may serve as indirect evidence for axion dark matter.

In this work, we study the properties of single-flavor heavy baryons, $\Omega_{\rm ccc}$ and $\Omega_{\rm bbb}$, in a strong magnetic field. For that sake, we simply treat the baryons as quark-diquark two-body systems, and a systematic formalism is developed to deal with two-body Schr$\ddot{\text o}$dinger equations in a magnetic field. It is found that: 1. The orbital properties of $\Omega_{\rm bbb}$ are almost not affected by the magnetic field. 2. $\Omega_{\rm ccc}$ is more tightly bound in the presence of a magnetic field. 3. The magnetic-spin effect dominates over the magnetic-orbital effect. Applying to peripheral heavy ion collisions, $\Omega_{\rm ccc}$ is much better than $\Omega_{\rm bbb}$ to explore the magnetic effect, and the discovery of $\Omega_{\rm ccc}$ could be more promising.

We investigate the $S$- and $P$-wave phase shifts for the $DD^\ast$ and $BB^\ast$ scatterings using Lüscher's finite-size method under twisted boundary conditions to search for doubly charmed tetraquaks, $T_{cc}^+$, and doubly bottomed tetraquarks, $T_{bb}^-$ as the hadronic bound states. The $T_{cc}^+$ state was observed as a peak just bellow the $DD^*$ threshold by LHCb Collaboration, while the $T_{bb}^-$ state is a theoretically predicted tetraquark state having heavier quark flavors $bb\bar u \bar d$. Lüscher's finite-size method is one of the well established methods for calculating the scattering phase shifts between two hadrons in lattice QCD simulations. Several studies have used simulations under the periodic boundary condition to determine the scattering phase shifts at a few discrete momenta for the $DD^*$ system. However, the scattering phase shift has not been investigated for the $BB^*$ system. In this study, $S$- and $P$-wave scattering phase shifts for the $DD^*$ and $BB^*$ systems in both $I=0$ and $I=1$ channels under several types of partially twisted boundary conditions. The use of the partially twisted boundary conditions enables us to obtain the scattering phase shift at any momentum by continuously varying the twisting angle. It also allows us to easily access the $P$-wave scattering phase shifts through the mixing of $S$- and $P$-waves, which is induced by the imposed boundary conditions. The 2+1 flavor PACS-CS gauge ensembles at $m_\pi=295$, 411 and 569 MeV are used. For charm and bottom quarks, the relativistic heavy quark action is adopted to reduce the lattice discretization artifacts due to the heavy quark mass. We discuss the emergence of a shallow bound state with a binding energy of $\mathcal{O}(100)$ keV at the physical pion mass in the $BB^*$ system, which has the quantum number $I(J^P)=0(1^+)$.

In the presence of an ultralight scalar or vector boson, a spinning black hole will be spun down through the superradiant instability. We use spin measurements from gravitational wave observations of binary black holes, in particular the heavy binary black hole merger event GW231123, along with the lower-mass GW190517 event, to constrain the existence of ultralight bosons. We disfavor scalars with masses in the range of $[0.55, 11]\times 10^{-13}$ eV and vectors in the range of $[0.11, 18]\times 10^{-13}$ eV, making only a conservative assumption that the black hole lifetimes are greater than $10^5$ years. The lower ends of these ranges, where the exclusion confidence is the highest, were not previously excluded by spin measurements from electromagnetic or gravitational wave observations. We map these constraints to axion and dark photon models with interactions.

Predictions of charm correlation functions and more specifically balance functions are presented in proton--proton (pp) collisions at sqrt(s_NN) = 13 TeV based on the PYTHIA 8.3 event generator. Correlations are computed for identical and cross-species charmed hadrons in both minimum bias and high-pT biased collisions. We study the strength of correlations as a function of the number of balanced flavors and investigate the impact of variations of PYTHIA parameters controlling the Lund string fragmentation on the shape and strength of the correlation functions. The feasibility of measurements of the charm balance function presented is discussed in the context of the future LHC experiments.

We perform a detailed analysis of the synchrotron signals produced by Dark Matter annihilations and decays. We consider different set-ups for the propagation of electrons and positrons, the galactic magnetic field and Dark Matter properties. We then confront these signals with radio and microwave maps, including Planck measurements, from a frequency of 22 MHz up to 70 GHz. We derive two sets of constraints: conservative and progressive, the latter based on a modeling of the astrophysical emission. Radio and microwave constraints are complementary to those obtained with other indirect detection methods, especially for dark matter annihilating into leptonic channels.

We assess the ability of the Belle II experiment to probe the Dirac or Majorana nature of a massive right-handed neutrino (RHN) $N$ in the MeV to GeV mass range. We consider the production and decay of RHNs to proceed via new interactions described by the standard model effective field theory (SMEFT) extended with right-handed neutrino fields (SMNEFT), and not via mass mixing with active neutrinos. We find that Belle II has the potential to discover $N$ if kinematically accessible. We perform detailed simulations of the angular distributions of lepton pairs from the decay of $N$ produced in two-body and three-body decays of $B$ mesons. We show that for $m_N$ above 100 MeV, Belle II can distinguish between Dirac and Majorana neutrinos at more than the 5$\sigma$ CL for most operators, and the combination of the production and decay operators can be identified from the subsequent decay of the heavy neutrino. Also, the production operators can be identified using three-body $B$ meson decay for any $m_N$ if the $B\to D\ell N$ and $B\to D^*\ell N$ events can be well separated.

Future $e^+e^-$ colliders are expected to play a fundamental role in measuring Standard Model (SM) parameters with unprecedented precision and in probing physics beyond the SM (BSM). This study investigates two-particle angular correlation distributions involving final-state SM charged hadrons. Unexpected correlation structures in these distributions is considered to be a hint for new physics perturbing the QCD partonic cascade and thereby modifying azimuthal and (pseudo)rapidity correlations. Using Pythia8 Monte Carlo generator and fast simulation, including selection cuts and detector effects, we study potential structures in the two-particle angular correlation function. We adopt the QCD-like Hidden Valley (HV) scenario as implemented in Pythia8 generator, with relatively light HV $v$-quarks (below about 100 GeV), to illustrate the potential of this method.

This work investigates hot quark matter under the thermodynamic conditions characteristic of a binary neutron star (BNS) merger remnants. We used the density-dependent quark mass model (DDQM) to access the microscopic nuclear equation of state (EoS) in a series of snapshots. The strange quark matter (SQM) is studied at finite temperature and entropy, in the presence of electrons and muons and their corresponding neutrinos to simulate the BNS merger conditions. For the first time, we introduced temperature into the DDQM model using a lattice QCD-motivated approach to construct both isentropic and isothermal EoSs. We observe that as the entropy of the SQM increases, the merger remnant becomes more massive and increases in size, whereas the neutrino abundance also increases. In the fixed-temperature case, on the other hand, we observe that the entropy spreads from the surface towards the center of the remnant. We determine the particle distribution in the core of the remnants, the structure of the remnant, the temperature profile, sound velocity, and the polytropic index, and discuss their effects. The strange-quark star (SQS) remnants satisfy the $2\,{\rm M_\odot}$ mass constraint associated with neutron stars (NS).

Dark photon dark matter (DPDM) emerges as a compelling candidate for ultralight bosonic dark matter, detectable through resonant conversion into photons within a plasma environment. This study employs in-situ measurements from the Parker Solar Probe (PSP), the first spacecraft to venture into the solar corona, to probe for DPDM signatures. The PSP in-situ measurements go beyond the traditional radio window, spanning frequencies between about 10 kHz and 20 MHz, a challenging range inaccessible to Earth-based radio astronomy. Additionally, the proximity of PSP to the resonant conversion location enhances the signal flux, providing a distinct advantage over ground-based observations. As a result, the PSP data establishes the most stringent constraints on the kinetic mixing parameter $\epsilon$ for DPDM frequencies between 70 kHz and 20 MHz, with values of $\epsilon \lesssim 10^{-14}-10^{-13}$. Investigating the data from STEREO satellites resulted in weaker constraints compared to those obtained from PSP. By utilizing state-of-the-art solar observations from space, we have surpassed the cosmic microwave background limits derived from early-universe observations.

Under the exponential parametrization scheme $ m^{\nu}_{ij}\sim r e^{i \theta}$, we propose a \emph{unique} neutrino mass matrix texture that exhibits four correlations among its elements. The mixing scheme obtained from the proposed texture is consistent with experimental observations. We construct a concrete model based on the $SU(2)_L \times U(1)_Y \times A_4 \times Z_{10} \times Z_7$ group within the framework of the seesaw mechanism.

Within the Standard Model Effective Field Theory framework, we set indirect constraints on top quark operators that violate baryon number by one unit above the TeV scale. We find that these constraints are typically many orders of magnitude more stringent than the recently derived direct bounds from collider experiments. Therefore, direct observation of baryon number violation in these top-quark observables at the TeV scale would imply a large fine-tuning among operators across different energy scales. This possibility is not protected under universal radiative corrections or any known symmetry principles.

This paper assesses the uncertainties inherent to parton shower simulations at double logarithmic accuracy, with a focus on their impact on jet quenching studies in high-energy heavy-ion collisions. For that purpose, we developed a massless quark-initiated vacuum parton shower toy-model with different evolution variables, such as inverse formation time, invariant squared mass, and squared opening angle. In addition to the effects of varying the ordering variable we further examine their corresponding kinematic reconstructions. The results highlight how these variations influence key distributions, including the number of splittings, angular and transverse momentum distribution of subsequent emissions. We also analyse the Lund distributions and their average trajectories, revealing that the choice of ordering variable has a significantly greater impact on the vacuum parton shower evolution than the kinematic scheme, particularly in large-angle emission regions. When a simple jet quenching model based on decoherence is implemented, we observe that the fraction of quenched events is sensitive to the ordering prescription, especially for the first splitting and thin media, highlighting the need for a deeper understanding of the branching process in the presence of an extended QCD media.

Infrared singularities in perturbative Quantum Chromodynamics (QCD) are captured by the Soft function, which can be calculated efficiently using Feynman diagrams known as webs. The starting point for calculating Soft function using webs is to compute the web mixing matrices using a well known replica trick algorithm. We present a package implemented in Mathematica to calculate these mixing matrices. Along with the package, we provide several state-of-the art computations.

Machine learning is becoming increasingly popular in the context of particle physics. Supervised learning, which uses labeled Monte Carlo (MC) simulations, remains one of the most widely used methods for discriminating signals beyond the Standard Model. However, this paper suggests that supervised models may depend excessively on artifacts and approximations from Monte Carlo simulations, potentially limiting their ability to generalize well to real data. This study aims to enhance the generalization properties of supervised models by reducing the sharpness of local minima. It reviews the application of four distinct white-box adversarial attacks in the context of classifying Higgs boson decay signals. The attacks are divided into weight-space attacks and feature-space attacks. To study and quantify the sharpness of different local minima, this paper presents two analysis methods: gradient ascent and reduced Hessian eigenvalue analysis. The results show that white-box adversarial attacks significantly improve generalization performance, albeit with increased computational complexity.

The Peccei-Quinn ($PQ$) mechanism is applied to the $\mathrm{SU(3)_c \otimes SU(3)_L \otimes U(1)_X}$ model with $U(1)_{B-L}$ symmetry. The structures in the $PQ$ charges of all fermions and scalar fields in the model are investigated by applying the invariant condition under the symmetry group on all Yukawa interaction terms. All defined $PQ$ charges just depend on $PQ$ charge of the only complex singlet scalar which causes the $U(1)_{PQ}$ symmetry breaking in the model. The mixing and mass hierachy in the scalar sector of the model are studied in detail. The constraint on $PQ$ charges and imaginary parts of scalars is derived. It is shown that only neutral scalar fields carry $PQ$ charges while charged ones do not. As the result, the physical state of axion which obeys the invariant under $\mathrm{SU(3)_L \otimes U(1)_X}$ and $PQ$ transformation, is a linear combination of all imaginary parts associated with $X$ charges of scalar triplets whose vacuum expectation values lie in the denominators. The anomaly axion-fermion interactions are presented. Explicit expressions for axion and light Standard Model like Higgs boson are shown. Mass of the axion and its coupling to photon are derived. In this paper, the decays of the Standard Model like Higgs boson to a pair of either charged leptons or bottom quarks are presented and constrained. The new contribution of the Higgs sector to axion decays to a pair of photons is derived. This decay consists of two parts related to anomaly coupling and that is derived from the Higgs sector. The result shows that the first part is proportional to cube of axion mass, while the second one is of the first order in it. So, the contribution due to the anomaly coupling is suppressed.

We construct light-cone sum rules (LCSR) for the $B\to K^*$ form factors in the large recoil region using vacuum-to-$B$-meson correlation functions, and systematically calculate subleading-power corrections to these form factors at tree level, including next-to-leading power contributions from the hard-collinear propagator, the subleading effective current $\bar{q}\Gamma[i\slashed{D}_{\perp}/(2m_b)]h_v$, and twist-five/six four-particle higher-twist effects. By incorporating the available leading-power results at $\mathcal{O}(\alpha_s)$ and the corrections to higher-twist $B$-meson light-cone distribution amplitudes from our previous work, we improve the precision of theoretical predictions for $B\to K^*$ form factors and find that the subleading-power contributions amount to 30\% of the corresponding leading-power results. Employing the Bourrely-Caprini-Lellouch (BCL) parametrization, we determine the numerical results for $B\to K^*$ form factors across the full kinematic range through a combined fit of LCSR predictions in the large recoil region and lattice QCD results in the small recoil region. Using the newly obtained $B\to K^*$ form factors, we compute the branching fractions for the rare decays $B \to K^* \nu_\ell\bar{\nu}_\ell$ in the Standard Model, obtaining $\mathcal{BR}(\bar{B}^0 \to \bar{K}^{*0} \nu_\ell\bar{\nu}_\ell)=8.09(96)\times 10^{-6}$ and $\mathcal{BR}(\bar{B}^+ \to \bar{K}^{*+} \nu_\ell\bar{\nu}_\ell)=9.95(1.05)\times 10^{-6}$. Additionally, we predict that the longitudinal $K^*$ polarization fraction is $F_L=0.44(4)$.

Several key observables of the high-precision physics program at future lepton colliders will critically depend on the knowledge of the absolute machine luminosity. The determination of the luminosity relies on the precise knowledge of some reference process, which is in principle not affected by unknown physics, so that its cross section can be computed within a well-established theory, like the Standard Model. Quantifying the uncertainties induced by possible New Physics effects on such processes is therefore crucial. We present an exploratory investigation of light and heavy New Physics contributions to the small-angle Bhabha process at future $e^+e^-$ colliders and we discuss possible strategies to remove potential uncertainties originating from such contaminations by relying on observables that are independent of the absolute luminosity.

The FASER experiment was designed to study long-lived dark sector particles and neutrinos traveling in the forward direction at the LHC. Neutrinos are predominantly produced from meson decays, which also result in an intense energetic flux of muons in the forward direction regularly observed by FASER. So far, these muons are treated only as backgrounds to neutrino and new physics studies, and extensive effort is required to suppress them. In this study, we consider the opposite scenario and use muons produced in the forward direction to produce new muonphilic scalars, which can then be searched for at the FASER detector. To minimize the backgrounds for this search, we make use of an upgraded preshower component, which is expected to be installed at FASER before the end of Run 3, and is capable of spatially resolving two energetic photons. We find that FASER, and its upgrade, FASER2 can probe currently unconstrained regions of parameter space, including regions that can potentially explain the $(g-2)_{\mu}$ anomaly. This highlights the physics opportunities that the intense TeV muon beam at the LHC can bring.

Large-momentum effective theory (LaMET) provides an approach to directly calculate the $x$-dependence of generalized parton distributions (GPDs) on a Euclidean lattice through power expansion and a perturbative matching. When a parton's momentum becomes soft, the corresponding logarithms in the matching kernel become non-negligible at higher orders of perturbation theory, which requires a resummation. But the resummation for the off-forward matrix elements at nonzero skewness $\xi$ is difficult due to their multi-scale nature. In this work, we demonstrate that these logarithms are important only in the threshold limit, and derive the threshold factorization formula for the quasi-GPDs in LaMET. We then propose an approach to resum all the large logarithms based on the threshold factorization, which is implemented on a GPD model. We demonstrate that the LaMET prediction is reliable for $[-1+x_0,-\xi-x_0]\cup[-\xi+x_0,\xi-x_0]\cup[\xi+x_0,1-x_0]$, where $x_0$ is a cutoff depending on hard parton momenta. Through our numerical tests with the GPD model, we demonstrate that our method is self-consistent and that the inverse matching does not spread the nonperturbative effects or power corrections to the perturbatively calculable regions.

We examine the sterile neutrino dark matter production in the primordial plasma with lepton asymmetry unequally distributed over different neutrino flavors. We argue that with the specific flavor fractions, one can mitigate limits from the Big Bang Nucleosynthesis on the sterile-active neutrino mixing angle and sterile neutrino mass. It happens due to cancellation of the neutrino flavor asymmetries in active neutrino oscillations, which is more efficient in the case of inverse hierarchy of active neutrino masses and does not depend on the value of CP-phase. This finding opens a window of lower sterile-active mixing angles. Likewise, we show that, with lepton asymmetry disappearing from the plasma at certain intermediate stages of the sterile neutrino production, the spectrum of produced neutrinos becomes much colder, which weakens the limits on the model parameter space from observations of cosmic small-scale structures (Ly-$\alpha$ forest, galaxy counts, etc.). This finding reopens the region of lighter sterile neutrinos. The new region may be explored with the next generation of X-ray telescopes searching for the inherent peak signature provided by the dark matter sterile neutrino radiative decays in the Galaxy.

Galactic weak-scale Dark Matter (DM) particles annihilating into lepton-rich channels not only produce gamma-rays via prompt radiation but also generate abundant energetic electrons and positrons, which subsequently emit through bremsstrahlung or inverse Compton scattering (collectively called `secondary-radiation photons'). While the prompt gamma-rays concentrate at high-energy, the secondary emission falls in the MeV range, which a number of upcoming experiments (AMEGO, E-ASTROGAM, MAST...) will probe. We investigate the sensitivity of these future telescopes for weak-scale DM, focusing for definiteness on observations of the galactic center. We find that they have the potential of probing a wide region of the DM parameter space which is currently unconstrained. Namely, in rather optimistic configurations, future MeV telescopes could probe thermally-produced DM with a mass up to the TeV range, or GeV DM with an annihilation cross section 2 to 3 orders of magnitude smaller than the current bounds, precisely thanks to the significant leverage provided by their sensitivity to secondary emissions. We comment on astrophysical and methodological uncertainties, and compare with the reach of high-energy gamma ray experiments.

Finite-volume extrapolation is an important step for extracting physical observables from lattice calculations. However, it is a significant challenge for the system with long-range interactions. We employ symbolic regression to regress finite-volume extrapolation formula for both short-range and long-range interactions. The regressed formula still holds the exponential form with a factor $L^n$ in front of it. The power decreases with the decreasing range of the force. When the range of the force becomes sufficiently small, the power converges to $-1$, recovering the short-range formula as expected. Our work represents a significant advancement in leveraging machine learning to probe uncharted territories within particle physics.

In JCAP 11 (2024) 051, we discussed how different regimes (flavoured) of leptogenesis can be probed through a ``tomographic'' approach using primordial gravitational waves. By examining the theory's parameter space, we identified regions where right-handed neutrino mass-dependent non-standard cosmological expansion leaves characteristic imprints on propagating gravitational waves. Our analysis focused on inflationary blue-tilted gravitational waves, modeled by a power-law tensor power spectrum with a constant spectral index. The resulting double-peak spectrum -- where peak and dip frequencies are sensitive to leptogenesis parameters -- provided marked signatures of different leptogenesis regimes. In this follow-up article, we conduct a statistical analysis of two-flavour leptogenesis signals, particularly those producing a peak (more generally, a broken power-law signal) within the LISA frequency band. Using a Fisher matrix analysis, we delineate the regions of parameter space that LISA can probe with minimal uncertainty, accounting for galactic and extragalactic foregrounds along with LISA's instrumental noise.

The exact solution of the Dirac equation for fermions coupled to an external periodic chiral condensate (chiral spiral) is used to obtain the exact formula for the Wigner function (up to the quantum loop corrections). We find that the resulting expressions for various coefficients of the Wigner function exhibit properties that cannot be reproduced within the standard semiclassical expansion. The formula for the axial vector component of the Wigner function can be conveniently used to study spin polarization effects and illustrate connections between the spin density matrix and axial current. In particular, we find that during an adiabatic change of the periodic potential into a uniform one, the polarization vector is twisted from its original direction.

Rotation plays an important role in the evolution of most types of stars, in particular, it can have a strong influence on the evolution of a newly born proto-neutron star. In this study, we investigate the effects of rotation on four snapshots of the evolution of proto-neutron stars with hyperons and $\Delta$-resonances in their cores, from birth as neutrino-rich objects to maturity as cold, catalyzed neutron stars. We focus on the effects of uniform rotation on the macroscopic structure of the star at three rotational frequencies -- 346.53 Hz, 716 Hz, and the Kepler frequency. Our investigation indicates that the impact of rotation at frequencies of $346.53$~Hz and $716$~Hz causes minor changes in the maximum gravitational mass but leads to significant changes in the stellar radius, particularly for stars with masses smaller than $2$~\msun. However, we observe drastic changes in the star's mass and radius when considering the Kepler frequency. In addition, we investigate other relevant characteristics of the rotating proto-neutron stars as they evolve such as the moment of inertia, compactness, central temperature, and Kerr parameter. Our results suggest that the inclusion of new degrees of freedom in the stellar core lead the star to be more sensitive to rotational dynamics, owing to an increase in compactness, a decrease in the central temperature, and a decrease in the moment of inertia.

We present a comprehensive analysis of near-threshold photoproduction of $\rho^0$, $\omega$, and $\phi$ mesons on a deuterium target, utilizing published datasets from DESY and SLAC for $\rho^0$ and $\omega$ production, as well as data from the LEPS and CLAS Collaborations for $\phi$ production. In extracting the deuteron mass radius, we adopt a dipole parametrization for the scalar gravitational form factor, which effectively captures the $|t|$-dependence of the differential cross sections associated with vector meson photoproduction. In addition, results from alternative commonly used form factor parametrizations are also considered and compared. Employing the vector meson dominance (VMD) framework and invoking low-energy Quantum Chromodynamics (QCD) theorems, we extract the deuteron mass radius from near-threshold photoproduction data of $\rho^0$, $\omega$, and $\phi$ mesons. The mass radii obtained from the various datasets are found to be consistent within statistical uncertainties, yielding an average value of $2.03 \pm 0.13$ fm under the dipole form assumption. We also provide a detailed discussion of the sensitivity of the extracted radius to different choices of gravitational form factor models. Our result represents a significant improvement in precision compared to earlier estimates based solely on $\phi$ meson photoproduction, offering new constraints for theoretical models of nuclear structure and deepening our understanding of the mass distribution within the deuteron.

Relativistic charged particles generate intense electromagnetic fields, which can be modeled as a spectrum of quasi-real photons through the Equivalent Photon Approximation. These fields facilitate photon-photon fusion processes, i.e. $\gamma \gamma \rightarrow h\bar{h}$ ($h$ presents different hadron species), providing a unique probe of Quantum Electrodynamics in extreme field regimes and the structure of the QED vacuum. The relevant processes have been extensively studied in $e^+e^-$ collision experiments and are now increasingly attracting broad discussion in relativistic heavy-ion collisions as well. In this work, we utilize the $\sigma_{\gamma \gamma\rightarrow h\bar{h}}$ extracted from $e^+e^-$ experiments as input to compute the corresponding cross sections, i.e., $\sigma_{AA\rightarrow AA+h\bar{h}}$, at RHIC and LHC energies, providing theoretical references for future experimental studies at these facilities. We compare our calculated results with predictions from other models, and the significant discrepancies observed highlight substantial model uncertainties, underscoring the urgent need for additional experimental data to resolve these differences.

The analysis of RHIC hydrogen gas jet target polarimeter measurements of transverse analyzing powers $A_\text{N}(t)$ in proton-nucleus scattering requires accurate Coulomb corrections to both spin-flip and non-flip amplitudes. These corrections must cover a wide range of nuclear charges $Z$ and form factor slopes, with flexibility to vary form factors during data fitting. To avoid technically challenging calculations involving a small but finite fictitious photon mass, the Coulomb correction to the non-flip electromagnetic amplitude with an exponential form factor was related to the corresponding correction for the spin-flip amplitude. This approach allows soft photon contributions to all amplitudes, including those with non-exponential form factors, to be calculated in the massless photon limit using only analytical expressions and numerically stable integrals with nonsingular integrands and finite integration limits. In addition, an absorptive correction to the spin-flip electromagnetic amplitude, which plays a critical role in spin effects in forward polarized proton-nucleus scattering, was accurately evaluated.

Energy-energy correlator (EEC) is an event shape observable that characterizes the distribution of energy flux in collision events. We initiate the study of full-range EEC at hadron colliders, generalizing the extensively studied EEC in $e^+e^-$ collision as well as the transverse EEC in hadron collisions. We derive celestial blocks from Lorentz symmetry to perform partial wave decomposition of the EEC at hadron colliders. These celestial blocks are essentially conformal blocks on the 2d celestial sphere, which have additional dependence on the collinear spin of ``light-ray transition matrix'' along the collision axis. In this work, we perform the first leading-order (LO) analytic calculation of this observable in pure Yang-Mills theory and use it as an example to illustrate the block decomposition. Numerically, the block expansion demonstrates superior accuracy in the collinear limit compared to conventional power series expansion. Analytically, we observe in this example that the block coefficients exhibit analyticity in both collinear and transverse spin. In addition, we analyze several kinematic limits at LO -- collinear, back-to-back, opposite coplanar and Regge limit. While the first three limits naturally generalize their $e^+e^-$ collision counterparts or transverse EEC and are governed by soft-collinear dynamics, the Regge limit requires complete angular dependence and reveals BFKL physics. Phenomenologically, we propose a realistic experimental setup and briefly discuss how the convolution of parton distribution function modifies the perturbative EEC result. Our work suggests that the full-range EEC at hadron colliders is an elegant observable which probes a broader kinematic space and connects various regimes of different QCD dynamics through a single measurement.

We present a comprehensive study of the two-flavor Quark--Meson--Diquark (QMD) model by comparing a renormalization approach with a renormalization-group (RG) consistent mean-field formulation based on the functional renormalization group (FRG). The renormalized QMD model allows analytical investigations of key quantities such as the zero-temperature diquark gap and the critical temperature for color superconductivity, ultimately reproducing the exact BCS relation in the high-density limit. We carry out the same analysis for different schemes of RG-consistent QMD models. We show that the RG-consistent approach yields a phase diagram and thermodynamic properties qualitatively similar to those of the renormalized model, provided both are embedded within a unified scheme that ensures consistent vacuum properties. In particular, both treatments recover the Stefan--Boltzmann limit at high densities. On the other hand, whether the BCS relation for the critical temperature is satisfied depends on the details of the RG-consistent setup. Our results highlight the relevance of renormalization and RG-consistent methods for accurately capturing the thermodynamics of QMD and related effective models with diquark degrees of freedom.

We explore the Electroweak Supersymmetry (EWSUSY) scenario within the Minimal Supersymmetric Standard Model (MSSM) under the Generalized Minimal Supergravity (GmSUGRA) framework, given that the anomalous magnetic moment of the muon may now be consistent with the Standard Model (SM) prediction, we consider both signs of the Higgsino mass parameter, $\mu < 0$ and $\mu > 0$. A comprehensive scan of the parameter space is performed, subject to the experimental constraints from the LHC SUSY searches, Planck 2018 relic density, and LUX-ZEPLIN (LZ) direct detection limits. We identify the viable regions featuring neutralino dark matter production via coannihilation with stau, chargino, stop, sbottom, and gluino, as well as through $A$-funnel, Higgs-resonance, and $Z$-resonance mechanisms. Notably, the $\mu < 0$ scenario yields a broader allowed parameter space, including for the first time sbottom-neutralino coannihilation solutions in GmSUGRA, which are absent for $\mu > 0$. While the Higgs-pole and $Z$-pole regions for $\mu > 0$ are largely excluded by the current LZ bounds, substantial viable regions remain for $\mu < 0$. Gluino coannihilation scenarios are strongly constrained by the current LHC data. The characteristic mass ranges of interest include sbottoms (0.7-1.3~TeV), stops (up to 1.0~TeV for $\mu > 0$ and 1.3~TeV for $\mu < 0$), staus and charginos (up to 1.5~TeV), and pseudoscalar Higgs bosons in the $A$-funnel (0.4-1.4~TeV). Moreover, the supersymmetric contributions to the muon anomalous magnetic moment remain within a $2\sigma$ deviation from the SM prediction. And our findings suggest that significant portions of the parameter space can be probed at the future LHC SUSY searches and upcoming dark matter direct detection experiments.

We present a comprehensive and gauge-invariant study of the neutrino dipole portal at the energy frontier. Assuming negligible active-sterile mixing, we analyze sterile neutrino production via dimension-6 dipole operators coupling to the electroweak field strengths. The analysis incorporates both single- and double-gauge-boson effective interactions. We investigate novel collider signatures at the HL-LHC, the FCC-hh -- studied here in this context for the first time -- and a 10 TeV muon collider. Particular emphasis is placed on electroweak boson-initiated processes, which dominate in the high-mass regime above $\sim$1 TeV. At the muon collider, these VBF-like topologies enable production even when the dipole couples to non-muonic flavors, offering a unique and sensitive probe for different flavor scenarios. We derive sensitivity projections for various theoretical benchmarks, reaching dipole couplings down to $d_{\gamma}\sim 6\times10^{-7}$ GeV$^{-1}$ at FCC-hh and $d_{\gamma}\sim 2\times10^{-7}$ GeV$^{-1}$ at the muon collider.

We use Soft Collinear Effective Theory (SCET) to factorize the polarized Deep Inelastic Scattering (DIS) structure functions $g_1(x)$ and $g_2(x)$, and to sum Sudakov double logarithms of $1-x$. The analysis is done both in terms of lightcone parton distributions and their moments. Computing $g_2$ requires subleading SCET operators which contain gluons. We calculate the one-loop matching coefficients from QCD onto these subleading SCET operators, and the one-loop matching from SCET onto the parton distribution function (PDF). The PDF in SCET is given by a bilocal operator, rather than the trilocal operator used in the QCD analysis of $g_2$ for generic $x$. We compute the one-loop anomalous dimension of the PDF operator for any $x$, and show that as $x \to 1$, it factors into a single-variable evolution. We comment on the QCD anomalous dimensions of twist-three operators, their equation-of-motion relation, and connection to the SCET analysis. We briefly discuss the definition of axial operators in the BMHV scheme. As a side result, we derive the $1/N$ dependence of the QCD coefficient functions for $F_1$, $F_L$ and $g_1$ in the $N \to \infty$ limit, where $N$ is the moment, which is expected to hold to all orders in $\alpha_s$.

The Standard Model of particle physics is derived from first principles starting from the free Dirac Lagrangian. All known fermionic particle species plus three right handed neutrinos are obtained from ideals of a $C\ell_{8,0}$ algebra, with gauge symmetries arising as rotations of creation-annihilation operators and vacua. Triality originates both the strong force and three particle families with a mass hierarchy. Lorentz and gauge transformations are unified while avoiding the Coleman-Mandula theorem. Chirality stems unavoidably from rotations leaving the vacua invariant, with a predicted Weinberg angle of $\sin^2(\theta_W)=3/8$. The theory is anomaly-free and devoid of proton decay.

We build up a complete description of QCD phase structure by applying the parametrization of the chiral and deconfinement order parameters upon the calculations from functional QCD approaches. In particular in the first order phase transition region at high chemical potential, both the phase transition line using Maxwell construction and the coexistence boundary lines from the spinodal decompostion are determined. We compute the thermodynamic quantities including the number density, the energy density, the pressure and also the free energy for both stable and unstable phases of QCD. Additionally, after applying a phenomenological description of the inhomogeneity of the QCD free energy, we obtain the surface tension of the first order phase transition of QCD.

I present a modified version of the Manogue-Dray-Wilson `octions' model of elementary particles, that overcomes some of the objections to that model that have been raised. In particular, I restore the compactness of the Standard Model gauge group, and show how the symmetry-breaking of the weak $SU(2)$ relates to the symmetry-breaking between the three generations of elementary fermions. In the process of attempting to implement a Dirac equation for three generations of fermions simultaneously, it turns out that some parts of the $E_8$ model are not required for the Standard Model, which is entirely contained in the subalgebra $\mathfrak{so}(7,3)$. In particular a re-interpretation of the Dirac spinors allows us to interpret part of the model as quantum gravity, which is then compared to General Relativity. The general structure of the model shows that the mixing angles depend on masses, and that the masses emerge from quantum interactions with the dynamic background spacetime (vacuum). Some sample calculations are given to support these predictions.

We present a theoretical study of axion echoes in the context of multiple ALP models. We begin by reviewing the single ALP case, deriving the conditions for resonance and echo formation. Starting from a set of N ALPs coupling to the photon, we then derive the relevant echo equations for both coherent and incoherent configurations. In the former case, we show that the echo power scales with N leading to sharper amplification and potentially improving projected bounds discussed earlier in literature. Small mass splittings between the ALPs further increase this amplification, even for a N = 2 case. We also outline the potential experimental implications of our results and discuss prospects for detecting these echoes in a wide range of ALP masses. In the incoherent scenario, we show that the random phases lead to a suppression of the echo power, eventually resulting in observable signals akin to or even weaker than the single ALP case.

We report directed flow ($v_1$) of multistrange baryons ($\Xi$ and $\Omega$) and improved $v_1$ data for $K^{-}$, $\bar{p}$, $\bar{\Lambda}$ and $\phi$ in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=$27 and 200 GeV from the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). We focus on particles whose constituent quarks are not transported from the incoming nuclei but instead are produced in the collisions. At intermediate impact parameters, we examine quark coalescence behavior for particle combinations with identical quark content, and search for any departure from this behavior (``splitting'') for combinations having non-identical quark content. Under the assumption of quark coalescence for produced quarks, the splitting strength appears to increase with the electric charge difference of the constituent quarks in the combinations, consistent with electromagnetic effect expectations.

Finite-temperature one-loop renormalization of the Standard Model, coupled with dynamic metric, is conducted in this study. The entire analysis is coherently carried out by using the refined background field method, applied in the spirit of the Coleman-Weinberg technique. The general form of the propagator, introduced in our previous work to facilitate Feynman diagram computation in a general curved background, proves useful in the presence of time-dependent temperature. Its utilization allows for the renormalization analysis of a FLRW background to essentially reduce to that of a constant finite-T flat spacetime. For infrared physics, the actual curved background should be considered. The implications of our findings for cosmology, particularly the cosmological constant problem and Hubble tension, are discussed.

We demonstrate that a $\sim 2 \sigma$ discrepancy with the Planck-$\Lambda$CDM cosmology in DESI Luminous Red Galaxy (LRG) data in the redshift range $0.4 < z < 0.6$ with effective redshift $z_{\textrm{eff}} = 0.51$ translates into an unexpectedly large $\Omega_m$ value, $\Omega_m = 0.67^{+0.18}_{-0.17}$. We independently confirm that this anomaly drives the preference for $w_0 > -1$ in DESI data \textit{alone} confronted to the $w_0 w_a$CDM model. Given that LRG data at $z_{\textrm{eff}} = 0.51$ is at odds with Type Ia supernovae in overlapping redshifts, we expect that this anomaly will decrease in statistical significance with future DESI data releases leaving an increasing $\Omega_m$ trend with effective redshift at higher redshifts. We estimate the current significance of the latter in DESI data at $\sim 1.8 \sigma$ and comment on how it dovetails with independent observations. It is imperative to understand what makes DESI LRG data at $z_{\textrm{eff}} = 0.51$ an outlier when it comes to $\Omega_m$ determinations.

We investigate the hydrodynamic solutions for expanding bubbles in cosmological first-order phase transitions going beyond local thermal equilibrium approximation. Under the assumption of a tangenosidal field profile, we supplement the matching conditions with the entropy produced due to the interaction of the bubble wall with ambient plasma. This allows us to analytically compute the corresponding fluid profiles and find bubble-wall velocity. We show that due to the entropy production, two stable solutions corresponding to a deflagration or hybrid and a detonation can coexist. Finally, we use numerical real-time simulations of bubble growth to show that in such cases it is typically the faster detonation solution which is realised. This effect can be explained in terms of the fluid profile not being fully formed into the predicted steady-state solution as the wall accelerates past this slower solution.

The recent observational evidence of deviations from the $\Lambda$-Cold Dark Matter ($\Lambda$CDM) model points towards the presence of evolving dark energy. The simplest possibility consists of a cosmological scalar field $\varphi$, dubbed quintessence, driving the accelerated expansion. We assess the evidence for the existence of such a scalar field. We find that, if the accelerated expansion is driven by quintessence, the data favour a potential energy $V(\varphi)$ that is concave, i.e., $m^2=d^2V/d\varphi^2<0$. Furthermore, and more significantly, the data strongly favour a scalar field that is non-minimally coupled to gravity (Bayes factor $\log(B) = 7.34 \pm 0.6$), leading to time variations in the gravitational constant on cosmological scales, and the existence of fifth forces on smaller scales. The fact that we do not observe such fifth forces implies that either new physics must come into play on non-cosmological scales or that quintessence is an unlikely explanation for the observed cosmic acceleration.

In this work, we develop a generic formalism for the study of tensor perturbations induced at second order by first-order vector metric perturbations, dubbing these induced tensor modes $\textit{vector-induced gravitational waves}$ (VIGWs). Notably, considering an inflation-inspired power-law type magnetic field power spectrum of the form $P_B(k)\propto k^{n_\mathrm{B}}$ (where $n_{\rm B}$ is the magnetic spectral index), we show that the VIGW signal is enhanced for stiff post-inflationary EoS, with the maximum enhancement happening for $w=1$. We explicitly demonstrate this contribution is dominant over the first-order magnetically-sourced GWs. The VIGW spectrum exhibits a maximum at around the scale crossing the cosmological horizon at the end of reheating, $k_\mathrm{reh}$, with its present day peak amplitude scaling as $\Omega_{\rm GW}(k_{\rm reh},\eta_0)\propto \Delta N_{\rm reh}\times(H_{\rm inf}/M_{\rm Pl})^{8}$, where $H_{\rm inf}$ is the Hubble parameter at the end of inflation and $\Delta N_{\rm reh}$ the duration of the post-inflationary era in $e$-folds. For $w=1$ (kination) and $n_{\rm B}>-3/2$, one further obtains a nearly $n_{\rm B}$-independent frequency scaling of the GW spectrum of the form $\Omega_{\rm GW}(f,\eta_0)\propto \left(\frac{f}{f_{\rm reh}}\right)^{-2.8}$ for $f>f_\mathrm{reh}\equiv k_\mathrm{reh}/(2\pi)$. Finally, we highlight that the VIGW signal can be well within the detection bands of several next-generation interferometric GW missions at small scales. Indicatively, for $H_{\rm inf} \sim O(10^{7})\:\mathrm{GeV}$ and $O(10^{14})\:\mathrm{GeV}$, and $\Delta N_{\rm reh} \sim 15$ and $10$, the VIGW signal is expected to be detectable by LISA and ET respectively.