There is great interest within the particle physics community for building a $\mu^+\mu^-$ collider with center-of-mass (CoM) energies ranging from $\sqrt{s}\sim$ 1-14 TeV. For Beyond-the-Standard-Model (BSM) physics, natural supersymmetry seems perhaps the most motivated, plausible extension of the Standard Model. Here, we examine what can be accomplished by a muon collider with regards to natural SUSY at various muon collider CoM energies. In natural SUSY -- especially in the guise that would emerge from the string landscape -- one expects sparticles to be spread over two orders of magnitude in mass values. A muon collider with highly variable beam energies would be most useful for targeting 2-body reaction thresholds and Higgs boson resonances.

We investigate the nonleptonic two-body weak decays of the single bottom baryon $\Omega_{b}^{*}$ into $\Omega_{c}^{*}P(V)$ final states within the framework of QCD factorization. Employing the QCD factorization framework and incorporating the contributions from the current-current operators, we compute the decay amplitudes and decay widths of the $\Omega_{b}^{*}\rightarrow\Omega_{c}^{*}P(V)$ processes in terms of the $\Omega_{b}^{*}\rightarrow\Omega_{c}^{*}$ transition form factors. Here, $P$ and $V$ denote pseudoscalar and vector mesons, respectively. Using the form factors obtained in our previous work, we evaluate the numerical values of the decay widths and branching fractions for all relevant weak channels. This study complements our previous analysis of the semileptonic weak transitions $\Omega_{b}^{*}\rightarrow\Omega_{c}^{*}\ell\bar{\nu}_{\ell}$ reported in Ref.~\cite{Amiri:2025gcf}, thereby providing a comprehensive investigation of all possible $\Omega_{b}^{*}\rightarrow\Omega_{c}^{*}$ weak decays of the $\Omega_{b}^{*}$ baryon.

We study electromagnetic leptogenesis (EMLG) in the low-scale, resonant regime within a fully effective-field-theory (EFT)--consistent framework. Starting from a UV Lagrangian and performing a one-loop matching to obtain the gauge-invariant dipole operator $O_{NB}$ with its Wilson coefficient $C_{NB}$, we implement the Pilaftsis--Underwood resummation for the self-energy contributions to the CP asymmetries and evolve a flavour covariant transport system across the electroweak window. In the quasi-degenerate limit $M_m-M_i\simeq\varGamma_m/2$, the CP-odd source acquires a Breit--Wigner--form enhancement whereas the washout saturates, with the freeze-out baryon asymmetry achieving $Y_B^{\rm FO}\gtrsim 10^{-10}$ across the strong-washout regime, comfortably above the observed value $Y_B^{\rm obs}\simeq 8.7\times 10^{-11}$. This establishes resonant EMLG at $O(100)~{\rm GeV}$ as a viable EFT-based mechanism for the baryon asymmetry of the Universe.

We introduce WimPyC, a Python code for the calculation of the capture rate of Weakly Interacting Massive Particles (WIMPs) by celestial bodies through nuclear scattering in the optically thin regime. WimPyC is an extension of the WimPyDD code, that calculates WIMP-nucleus scattering signals in direct detection (DD) experiments, and allows to combine DD and capture in celestial bodies in virtually any scenario within the framework of Galilean-invariant non-relativistic effective theory (NREFT), including inelastic scattering, an arbitrary WIMP spin and a generic WIMP velocity distribution in the Galactic halo. WimPyDD and WimPyC are suitable for both top-down approaches, where the interaction operators of a high-energy physics model are matched to those of the NREFT, and to bottom-up studies, where the Wilson coefficients of the NREFT are explored in a model-independent way and/or where the velocity distribution is written in terms of a superposition of streams taken as free parameters. As in the case of WimPyDD WimPyC exploits the factorization of the three main components that enter in the calculation of the capture rate: i) the Wilson coefficients that encode the dependence of the signals on the ultraviolet completion of the effective theory; ii) a response function that depends on the nuclear physics; iii) the halo function that depends on the WIMP velocity distribution. In WimPyC these three components are calculated and stored separately for later interpolation and combined together only as the last step of the signal evaluation procedure. This makes the phenomenological study of the capture rate with WimPyC transparent and improves computational speed.

We have made a thorough study of the $D^+ \to \pi^+ \eta \eta $ reaction, recently measured by the BESIII collaboration, which shows an abnormal strength at high invariant masses in the $\pi\eta$ mass distribution. We studied in detail the triangle mechanism and the $f_0(1370)$ excitation modes that have been suggested to explain this abnormal feature, and concluded that they are too small to have any important role in the solution to that problem. We have also studied other possible solutions evaluating the contribution of excitations of other $f_0$, $a_0$ and $f_2$ resonances and reached the same conclusion. Unexpectedly, the solution to the problem is found considering the $f_0(980)$ excitation, with the $f_0(980)$ decaying to two $\eta$, which is tied to the $a_0(980)$ production, and well under control. At the same time, the consideration of the $f_0(980)$ excitation solves another non reported problem, which is the $\eta \eta$ mass distribution that comes when only the $a_0(980)$ resonance is allowed to be excited, which produces a large deficiency at low invariant masses compared with experiment.

We report the calculation of the process $e^+ e^- \to J/\psi J/\psi$ up to next-to-next-to-leading order (NNLO) at a center-of-mass (CM) energy of $\sqrt{s}=10.58$ GeV. We employ an improved NRQCD factorization approach, decomposing the amplitude into photon-fragmentation and non-fragmentation components. The fragmentation contribution is determined using the measured $J/\psi$ decay constant, while the interference and non-fragmentation parts are computed at NNLO in $\alpha_s$ and lowest order in velocity. In this optimized scheme, both ${\cal O}(\alpha_s)$ and ${\cal O}(\alpha^2_s)$ corrections in the interference part are positive and exhibit good convergence. The non-fragmentation part is numerically insignificant. Our results indicate that with the projected 50 ${\rm ab}^{-1}$ dataset at \texttt{Belle 2}, the prospects for observing exclusive double $J/\psi$ production are very promising.

We study the semileptonic decay of its SU(3) partner, the $\Lambda_c \to \Lambda \ell^+ \nu_\ell$ ($\ell = e, \mu$) transition, within the framework of light-cone QCD sum rules (LCSR) by using the distribution amplitudes of heavy $\Lambda_c$ baryon. The numerical analysis is performed using two different sets of $\Lambda_c$ baryon light-cone distribution amplitudes. The resulting form factors are parametrized by a model-independent $z$-series expansion and used to compute the differential and total decay widths. Our predictions for the branching fractions are in good agreement with the latest BESIII measurements and with lattice-QCD results.

In the Standard Model, partial unification of the non-Abelian running gauge couplings is achieved at the scale $\mu^{\rm SM}_{32} \approx 2.8 \times 10^{16}$ GeV. Elaborating on this fact, we discuss a simple general parametrization for the new physics corrections leading to full unification at some scale $M_X$. We show that for any new physics model such that the corrections to the non-Abelian couplings are equal (or nearly so), $M_X$ is equal (or close to) the partial unification scale $\mu^{\rm SM}_{32}$; the latter scales could be disentangled only if the corrections to the non-Abelian couplings are significantly different. We explore how the parametrization works for some relevant models with new physics below $M_X$, as low energy supersymmetry, split supersymmetry, etc. As for models with a desert up to $M_X$, we explore in particular how the parametrization works for string inspired corrections; we find a phenomenologically remarkable possibility for unification at about $100$ TeV, suggesting a low string scale, in addition to the more conservative possibility for unification at $\mu^{\rm SM}_{32}$.

We determine the strong coupling from high-energy data for the Drell-Yan (DY) process and top-quark hadro-production collected at the Large Hadron Collider and the Tevatron combined with the world data on deep-inelastic scattering (DIS) and fixed-target DY data. The theory description uses results at next-to-next-to-leading order in perturbative QCD in the $\overline{\mathrm{MS}}$-scheme together with leading order QED evolution. The DIS data are subject to stringent kinematic cuts to suppress the contribution of power corrections. We apply a cut on the hadronic invariant mass squared $W^2 \geq 12.5~$GeV$^2$ together with a series of cuts on momentum transfer squared $Q^2$. Discarding higher-twist terms we find that the value of strong coupling $\alpha_s(m_Z)$ preferred by the data stabilizes at large enough cuts on $Q^2$, when low-$Q^2$ DIS data sensitive to power corrections are effectively removed. In particular, we extract the value of $\alpha_s(m_Z,N_f=5)=0.1152 \pm 0.008$ for $N_f=5$ light flavors with the cut $Q^2>10~$GeV$^2$. In the absence of higher-twist terms less tight cuts on $Q^2$ show a clear deterioration of the fit and lead to rising values of the strong coupling, shifted upwards by about two standard deviations.

Cosmological phase transitions are a frequent phenomenon in particle physics models beyond the Standard Model, and the corresponding gravitational wave signal offers a key probe of new physics in the early Universe. Depending on the underlying microphysics, the transition can exhibit either direct or inverse hydrodynamics, leading to a different phenomenology. Most studies to date have focused on direct transitions, where the cosmic fluid is pushed or dragged by the expanding vacuum bubbles. In contrast, inverse phase transitions are characterized by fluid profiles where the plasma is sucked in by the expanding bubbles. Using the sound shell model, we derive and compare the gravitational wave spectra from sound waves for direct and inverse phase transitions, providing new insights into the potential observable features and the possibility of discriminating among the various fluid solutions in gravitational wave experiments.

At the end of 2016, we computed the five-loop (N$^4$LO) contributions to the beta function in perturbative Quantum Chromodynamics (QCD), its generalization to non-Abelian gauge theories with a simple compact Lie group, and for Quantum Electrodynamics (QED). Here we recall main tools used in and specifically developed for this computation and its main analytic and numerical results. The development work carried out for this project facilitated further even more involved analytic five-loop computations. We briefly summarize also their numerical QCD results for Higgs-boson decay to hadrons in the heavy-top limit and for two N$^4$LO splitting functions for the evolution of quark distributions of hadrons. The latter lead to a first realistic estimate of the five-loop contribution to another important quantity in perturbative QCD, the quark cusp anomalous dimension.

We present the electroweak corrections for the production of a photon pair through gluon fusion, focusing on the contribution from the first two generations of quarks. The two-loop amplitude is calculated using a series of projection operators which define scalar form factors. In order to evaluate the Master Integrals which appear in this process we employ both generalized polylogarithms and Chen-iterated integrals. In order to perform a phenomenological study we develop a semi-numerical evaluation of the Master Integrals employing a fitting procedure to speed up the evaluation of burdensome higher weight contributions. We present results for the LHC, finding corrections of around a couple of percent to the leading order $gg \rightarrow \gamma\gamma$ process. Our results are implemented into the parton-level Monte Carlo code \texttt{MCFM}.

The Compton process with the initial states of photons and neutrons described by the density matrices of a general form is studied for low energies of photons. The coherent contribution to the inclusive probability to record a photon is investigated in detail. This contribution gives the hologram of the neutron one-particle density matrix. The evolution of the Stokes parameters of scattered photons is described. The susceptibility tensor of a neutron gas and a wave packet of a single neutron is obtained. The explicit expression for the photon polarization operator in the presence of free neutrons is derived. It turns out that this polarization operator possesses pole singularities in the short wavelength approximation. These singularities corresponding to the additional degrees of freedom are identified with plasmons and the respective plasmon-polaritons are described. There are eight independent plasmon-polariton modes in a neutron gas and on a single neutron wave packet. Some plasmon-polariton modes prove to be tachyonic and unstable manifesting a spontaneous generation of the magnetic field. The estimates of the parameters of the neutron gas when it becomes ferromagnetic are found. In the infrared limit, the neutron wave packet behaves in coherent Compton scattering as a point particle with dynamical magnetic moment, the additional degrees of freedom being reduced to the dynamical part of the magnetic moment.

We provide the last missing ingredient necessary to approximate one-loop amplitudes in QCD with massive quarks in the limit of vanishing energy of a single gluon up to terms suppressed by this energy. Our main result is a soft operator acting in color and spin space that manipulates the momenta of the hard partons while keeping them on-shell and respecting momentum conservation. Additionally, we provide a complete expression for the subleading term of the expansion of an arbitrary tree-level amplitude in the limit where the momenta of a massless quark and a massless anti-quark of the same flavor become collinear. This limit is necessary to obtain the one-loop soft approximation whenever the process involves such a quark-anti-quark pair. Interestingly, the result involves a high-energy limit.

Dark matter particles with sufficiently large interactions with ordinary matter can scatter in the Earth's atmosphere and crust before reaching an underground detector. This Earth-shielding effect can induce a directional dependence in the dark matter flux, leading to a sidereal daily modulation in the signal rate. We perform a search for such a modulation using data from the SENSEI experiment, targeting MeV-scale dark matter. We achieve an order-of-magnitude improvement in sensitivity over previous direct-detection bounds for dark-matter masses below 1 MeV, assuming the Standard Halo Model with a Maxwell--Boltzmann velocity distribution, and constrain the amplitude of a general daily modulation signal to be below 6.8 electrons per gram per day.

The Pierre Auger Observatory (Auger) and the Telescope Array (TA) are the world's two largest ultra-high-energy cosmic ray (UHECR) observatories. They operate in the Southern and Northern hemispheres, respectively, at similar latitudes but with distinct surface detector (SD) designs. A significant challenge in studying UHECR physics across the full sky is the apparent discrepancy in flux measurements between the two experiments. This discrepancy could arise from astrophysical differences and/or systematic effects related to their detector designs and sensitivities to extensive air shower components. To address this, the Auger@TA working group aims to cross-calibrate the two observatories with a self-triggering micro-Auger array within the TA array. This micro-array consists of eight Auger Surface Detector (SD) stations equipped with Water Cherenkov Detectors (WCDs) and AugerPrime Surface Scintillator Detectors. Seven SD stations, configured with a centered-1-PMT design, are arranged in a hexagonal pattern with one station in the center, with 1.5 km spacing, mirroring the Auger layout. The eighth station, which features a standard 3-PMT Auger station, is located in conjunction with a TA detector at the center of the hexagon, forming a triplet for high-statistics and low-uncertainty cross-calibration. A custom communication system that uses readily available components enables seamless communication between stations and remote access to each station through a central computer. The micro-array is now fully deployed, and initial data-taking is about to start. This presentation will detail the instrumentation, communication systems, central data acquisition system, expected performance of the micro-array, and preliminary results as appropriate.

We investigate meson-exchange currents (MEC) in the one-particle emission transverse response of nuclear matter, incorporating short-range correlations via the Bethe-Goldstone equation with a realistic nucleon-nucleon interaction. The interference between one-body and two-body currents, strengthened by the high-momentum components of correlated pairs, produces a marked enhancement of the transverse response. We also indicate how the formalism extends to neutrino scattering, where similar effects are expected to impact oscillation experiments.

We report a search for ultra-heavy dark matter (UHDM) with the CDEX-10 experiment at the China Jinping Underground Laboratory (CJPL). Using a Monte Carlo framework that incorporates Earth shielding effects, we simulated UHDM propagation and energy deposition in p-type point-contact germanium detectors ($p$PCGe). Analysis of 205.4 kg$\cdot$day exposure in the 0.16-4.16 keVee range showed no excess above background. Our results exclude the spin-independent UHDM-nucleon scattering with two cross section scales, with the UHDM mass from $10^6$ GeV to $10^{11}$ GeV, and provide the most stringent constraints with solid-state detectors below $10^8$ GeV.

Sharing the amazing achievements of the (particle) physics world with the general public is at the heart of the mission of the Subatomic Heroes, based at the University of Siegen, Germany. Originally this started out as an endeavor of theoretical particle physics, now we are steadily spreading out to cover and include more branches of physics and science. Our activities range from merging art with public physics lectures via marvelous artistic performances at the local theater, over dedicated events for high-school students, to our Subatomic Heroes channel on Instagram and TikTok where you may also find out when and where our famous "hadronic ice-cream" will be served next! So follow us on this https URL and this https URL.

Gravitational-wave (GW) events are generally believed to originate in galaxies and can thus serve, like galaxies, as tracers of the universe's large-scale structure. In GW observations, waveform analysis provides direct measurements of luminosity distances; however, the redshifts of GW sources cannot be determined due to the mass-redshift degeneracy. By cross-correlating GW events with galaxies, one can establish a correspondence between luminosity distance and redshift shells, enabling cosmological inference. In this work, we explore the scientific potential of cross-correlating GW sources detected by third-generation (3G) ground-based GW detectors with the photometric redshift survey of the China Space Station Survey Telescope (CSST). We find that the constraint precisions of the Hubble constant and the matter density parameter can reach $1.04\%$ and $2.04\%$, respectively. The GW clustering bias parameters $A_{\rm GW}$ and $\gamma$ can be constrained to $1.52\%$ and $4.67\%$, respectively. These results highlight the significant potential of the synergy between CSST and 3G ground-based GW detectors in constraining cosmological models and probing GW source formation channels using cross-correlation of dark sirens and galaxies.

The redshifted 21-cm signal from the dark ages offers a powerful probe of cosmological models and the underlying dark matter microphysics. We investigate deviations from the standard $\Lambda$CDM prediction, an absorption trough of approximately $-40.6\,\mathrm{mK}$ at redshift $z \simeq 85.6$, in the context of co-SIMP dark matter. The strength of co-SIMP interactions, quantified by the parameter $C_{\rm int}$, enhances the absorption depth and shifts the trough to higher redshifts. For example, a model with $C_{\rm int}=1.0$ produces a minimum brightness temperature of $-50.6\,\mathrm{mK}$ at $z \simeq 86.2$. The 21-cm power spectrum increases with $C_{\rm int}$ in addition to the global signal. We assess the detectability of these signatures using signal-to-noise ratio (SNR) and Fisher matrix forecasts. The maximum SNR reaches $\sim 15.7$ for $C_{\rm int}=1.0$ for the global signal. Fisher forecast for $1,000$ hours of integration time shows that this model can be distinguished from a null-signal at $4.3\sigma$ and from the $\Lambda$CDM model case at $1.6 \sigma$, with order-of-magnitude improvements for 100,000 hours of integration. For the 21-cm power spectrum, our forecasts reveal complementary trends; with a modest setup (collecting area of $5\,\mathrm{km}^2$ and 1,000 hours of integration time), the $C_{\rm int}=1.0$ model can be detected at $4.63\sigma$ and differentiated from the standard scenario at $1.78 \sigma$. These findings highlight the potential of the 21-cm cosmology to probe the properties of dark matter and demonstrate that upcoming dark ages experiments, particularly space-based and lunar observations, can offer a promising avenue to test co-SIMP models.

We consider two-point functions of light fields at finite temperature and large real frequencies in holographic theories. The thermal system is dual to a single-sided AdS black hole. We show that the high-frequency expansion obtained from the Operator Product Expansion receives nonperturbative corrections, which are controlled by null geodesics bouncing off the black hole singularity in the two-sided eternal black hole geometry. We develop a bulk WKB description of these bouncing geodesics and explain how to calculate reflection coefficients at the singularity.

Measurements of Higgs boson processes by the ATLAS and CMS experiments at the LHC use Simplified Template Cross Sections (STXS) as a common framework for the combination of measurements in different decay channels and their further interpretation, e.g. to measure Higgs couplings. The different Higgs production processes are measured in predefined kinematic regions -- the STXS bins -- requiring precise theory predictions for each individual bin. In gluon-fusion Higgs production a main division is into 0-jet, 1-jet, and $\geq 2$-jet bins, which are further subdivided in bins of the Higgs transverse momentum $p_T^H$. Requiring a fixed number of jets induces logarithms $\ln p_T^{\mathrm{cut}}/Q$ in the cross section where $p_T^{\mathrm{cut}}$ is the jet-$p_T$ threshold and $Q\sim p_T^H\sim m_H$ the hard-interaction scale. These jet-veto logarithms can be resummed to all orders in perturbation theory to achieve the highest possible perturbative precision. We provide state-of-the art predictions for the $p_T^H$ spectrum in exclusive $H+$1-jet production and the corresponding $H+$1-jet STXS bins in the kinematic regime $p_T^{\mathrm{cut}} \ll p_T^H\sim m_H$. We carry out the resummation at NNLL$'$ accuracy, using theory nuisance parameters to account for the few unknown ingredients at this order, and match to full NNLO. We revisit the jet-veto factorization for this process and find that it requires refactorizing the total soft function into a global and soft-collinear contribution in order to fully account for logarithms of the signal jet radius. The leading nonglobal logarithms are also included, though they are numerically small for the region of phenomenological interest.

We present a first assessment of how the previously unexplored effect of positronium formation can impact on the value of the effective number of neutrino species in the Standard Model, $N_{\rm eff}^{\rm SM}$. Adopting a Yukawa form for the electrostatic potential, we discuss two possible scenarios that differ primarily in their assumptions about entropy evolution. The first, out-of-equilibrium scenario assumes that thermal corrections to the potential such as Debye screening prevent positronium from appearing until the temperature drops below a threshold. Once the threshold is reached, entropy generated in the QED sector from the equilibration process, if instantaneous, leads to a variation in $N_{\rm eff}^{\rm SM}$ of at most $|\Delta N_{\rm eff}| \sim 10^{-4}$, comparable to other uncertainties in the current benchmark value for $N_{\rm eff}^{\rm SM}$. A more gradual formation could however yield a larger change. The second, equilibrium scenario assumes the QED sector to stay in equilibrium at all times. In this case, we show that cancellations between the first, $s$-wave bound- and scattering-states contributions ensure that it is possible to evolve the system across the bound-state formation threshold without generating entropy in the QED sector. The corresponding change in $N_{\rm eff}^{\rm SM}$ then closely matches the $\mathcal{O}(e^2)$ perturbative result derived in previous works and the $\mathcal{O}(e^4)$ contribution is capped at $|\Delta N_{\rm eff}| \lesssim 10^{-6}$. We also comment on the impact of deviations from a pure Yukawa potential due to the presence of a thermal width.

The Drell-Levy-Yan relation is employed to obtain pion and kaon elementary fragmentation functions (EFFs) from the hadron-scale parton distribution functions (DFs) of these mesons. Two different DF sets are used: that calculated using a symmetry-preserving treatment of a vector $\times$ vector contact interaction (SCI) and the other expressing results obtained using continuum Schwinger function methods (CSMs). Thus determined, the EFFs serve as driving terms in a coupled set of hadron cascade equations, whose solution yields the complete array of hadron-scale fragmentation functions (FFs) for pion and kaon production in high energy reactions. After evolution to scales typical of experiments, the SCI and CSM FF predictions are seen to be in semiquantitative agreement. Importantly, they conform with a range of physical expectations for FF behaviour on the endpoint domains $z\simeq 0, 1$, e.g., nonsinglet FFs vanish at $z=0$ and singlet FFs diverge faster than $1/z$. Predictions for hadron multiplicities in jets are also delivered. They reveal SU$(3)$ symmetry breaking in the charged-kaon/neutral-kaon multiplicity ratio, whose size diminishes with increasing reaction energy, and show that, with increasing energy, the pion/kaon ratio in $e^+ e^- \to h X$ diminishes to a value that is independent of hadron masses.

Accurate comparisons between theoretical models and experimental data are critical for scientific progress. However, inferred physical model parameters can vary significantly with the chosen physics model, highlighting the importance of properly accounting for theoretical uncertainties. In this Letter, we present a Bayesian framework that explicitly quantifies these uncertainties by statistically modeling theory errors, guided by qualitative knowledge of a theory's varying reliability across the input domain. We demonstrate the effectiveness of this approach using two systems: a simple ball drop experiment and multi-stage heavy-ion simulations. In both cases incorporating model discrepancy leads to improved parameter estimates, with systematic improvements observed as additional experimental observables are integrated.

In this work, we investigate the doubly bottom $H_{(s)}\bar{T}_{(s)}$ and $H_{(s)}T_{(s)}$ systems by adopting the one-boson-exchange model, where $H_{(s)}$ and $T_{(s)}$ represent $S$-wave $B^{(*)}_{(s)}$ and $P$-wave $B^{(*)}_{(s)1,2}$ doublets, respectively. For the $H\bar{T}$ systems, we predict some loosely bound states in the $I(J^{PC})=0(1^{-\pm})$ $B\bar{B}_{1}$, $I(J^{PC})=0(2^{-\pm})$ $B\bar{B}_{2}^{*}$, $I(J^{PC})=0(1^{-\pm})$ $B^*\bar{B}_{1}$ and $I(J^{PC})=0(2^{-\pm})$ $B^*\bar{B}_{2}^{*}$ channels, which are the most promising hidden bottom molecular tetraquarks. For the $HT$ systems, the $B^*B_1$ channels with quantum numbers $I(J^P) = 0(1^{-}), 0(2^{-})$ and the $B^*B_2^*$ channels with $I(J^P) = 0(2^{-})$ are also likely candidates for forming molecular tetraquarks. In contrast, no molecular candidates have been identified in the bottom-strange sectors. One can hope that our predictions will provide valuable insights to the LHCb and Belle II Collaborations as they continue to explore this fascinating field through experimental research.

We study the dependence of neutrino-induced $\gamma/\pi^0$ production ($\stackrel{ {(-)}}{\nu_\mu} + A \to \stackrel{ {(-)}}{\nu_\mu}(\mu) +\gamma/\pi^0 + X$) on the target nucleus A, at the $\Delta$ resonance mass region. Our conclusion is based on experimental data for $\pi^0$ production rates at photon-nucleus interactions from the A2 collaboration at the Mainz MAMI accelerator. We assume that $\Delta$ resonance decays are independent of the production mechanism (via photon, Z, or W boson). In Neutral Current (NC) interactions, the $1\pi^0 + X$ production scales as A$^{2/3}$. In contrast, photons from $\Delta$ decays typically escape the nucleus, resulting in a cross-section proportional to the atomic number A. Thus, in NC interactions, the ratio of $\gamma$ production to $\pi^0$ production is proportional to A$^{1/3}$. In Charged Current (CC) $\nu_\mu$($\bar \nu_\mu$) -induced production of $\Delta^+$ ($\Delta^0$) will be proportional to the number of neutrons (protons) in the nucleus. After $\Delta$ decay, due to the charge universality in strong interactions, the suppression factor for $\pi^0$ escaping the nucleus must also follow A$^{-1/3}$, as in NC interactions. We predict the ratio of the $\gamma / \pi^0$ production rates in NC and CC interactions and for $\nu_\mu$ and $\bar \nu_\mu$ beams: {Argon target}: $\sim$3.1\% (NC/CC $\nu_\mu/\bar \nu_\mu$). {\bf Water target}: $\sim$1.9\% (NC), $\sim$2.3\% (CC $\nu_\mu$), $\sim$1.7\% (CC $\bar \nu_\mu$). {Liquid Scintillator target}: $\sim$1.7\% (NC), $\sim$2.1\% (CC $\nu_\mu$), $\sim$1.6\% (CC $\bar \nu_\mu$). We also discuss solving the MiniBooNE anomaly by looking at the CC single photon and single neutral pion production rates at the SBN program experiments at Fermilab.

Ultralight vector dark matter induces metric fluctuations that generate timing residuals in the arrival times of pulsar emissions through two distinct modes: a fast mode, sourced by coherent field oscillations, and a slow mode, arising from interference patterns. These modes enable the detection of vector dark matter with masses $m \sim 10^{-24} - 10^{-22}\ \mathrm{eV}$ and $m \sim 10^{-18} - 10^{-16}\ \mathrm{eV}$, respectively, using pulsar timing arrays. While previous studies have explored the fast mode, they neglect the full statistical treatment of the vector field and a precise treatment of its polarization structure. In this work, we investigate the timing residuals from both modes, fully accounting for the statistical properties of ultralight vector dark matter, assuming equipartition among its three polarization states. The two-point correlation functions of timing residuals that we derive serve as direct tools for identifying vector dark matter signatures as a stochastic background in pulsar timing data.

We present the first calculation of the high-energy corrections to the process of isolated photon production in association with two jets. These corrections both stabilise the perturbative behaviour in $m_{j_1j_2}$ and lead to a significantly improved description of data from a recent ATLAS measurement.

The transition amplitude of a kaon to a pion and two off-shell photons is studied. First, it is computed at leading order (one-loop level) of the Chiral Perturbation Theory expansion. Explicit analytical results for the leading-order amplitude are presented, constituting the first complete calculation for the doubly off-shell case. Subsequently, it is reevaluated by employing a refined diagrammatic notation and a generic ansatz incorporating effects beyond leading order. The dependence on the underlying $K\pi PP$ vertex parameters is analyzed. This offers valuable insights into amplitude properties and allows inclusion of unitarity corrections from $K\to3\pi$, yielding the complete $K\to\pi\gamma^*\gamma^*$ amplitude structure. Both the charged and neutral channels are treated in parallel. The presented results provide crucial input for phenomenological studies of related rare decays like $K\to\pi\ell^+\ell^-[\gamma]$ or $K\to\pi\ell_1^+\ell_1^-\ell_2^+\ell_2^-$ and support ongoing precision measurements at experiments like NA62 at CERN. These results may also find application in other related processes, including $\eta^{(\prime)}$ decays.

Among the few ways that allow or could allow us to probe the early Universe from the observation of a flux of primordial particles, there is one possibility which has been little studied: the observation today of high energy neutrinos which could have been emitted shortly after the Big Bang, from the decay or annihilation of early universe relics. We perform a general study of such a possibility. To this end, we first emphasise that these neutrinos could display various kinds of sharp spectral features, resulting from the primary energy spectrum at emission, and from how this spectrum is smoothed by redshift and radiative correction effects. Next, we determine the ranges of mass (from a fraction of eV all the way to the Planck scale) and lifetime of the source particles along which we do not/we do expect that the sharp spectral feature will be altered by interactions of the neutrinos on their way to the detector, mainly with the cosmic neutrino background or between themselves. We also study the theoretical (i.e. mainly BBN and CMB) and observational constraints which hold on such a possibility. This allows us to delineate the regions of parameter space (mass, lifetime and abundance) that are already excluded, hopeless for future observation or, instead, which could lead to the observation of such neutrinos in the near future.

We investigate the role of vector boson fusion (VBF) and associated production with an electroweak boson (V-AP) of beyond-the-Standard-Model Higgses at the LHC in probing CP violation in extended Higgs sectors. Resonant production of a new Higgs boson through V-AP/VBF subsequently decaying into a Z boson and a 125 GeV Higgs boson h would be a robust sign of CP violation, since h has been measured to be (predominantly) a CP-even state. After identifying this and other sets of signatures which rely on V-AP/VBF to jointly uncover CP violation, we analyze the prospects to measure CP violation in this way for the complex two-Higgs-doublet-model at the High-Luminosity LHC.

We construct a Standard Model (SM) extension with $T^\prime\times Z_{10} \times Z_2$ symmetry for generating the expected neutrino mass matrix with the relation $(M_\nu)_{13}=(M_\nu)_{31}=-\frac{1}{2}(M_\nu)_{22}$ via the contributions of the Type-I seesaw and Weinberg-type operators. The proposed model possesses viable parameters capable of predicting the neutrino oscillation parameters being in good agreement with recent constraints. Our analysis reveals the predicted regions for the physical quantities, given as follows. The two mass squared splittings are $\delta m^2\in (69.360, 79.220)\, \mathrm{meV}^2$ and $\Delta m^2\in (2.484, 2.490)10^3\,\mathrm{meV}^2$ for normal ordering (NO) while $\delta m^2\in (69.450, 79.160)\, \mathrm{meV}^2$ and $\Delta m^2\in (-2.464, -2.456)10^3\,\mathrm{meV}^2$ for inverted ordering (IO). The lightest neutrino mass is $m_{\ell}\in (36.720, 36.780)$ meV for NO and $m_{\ell}\in (62.220,\, 62.310)$ meV for IO. The sum of neutrino mass is $\sum m_\nu \in (136.700,\, 136.800)$ meV for NO and $\sum m_\nu \in (221.400,\, 221.600)$ meV for IO. Two Majorana phases are predicted to be $\alpha\in (6.367, 6.380)^\circ$ and $\beta\in (6.936, 6.946)^\circ$ for NO while $\alpha \simeq 358.800^\circ$ and $\beta \simeq 0.600^\circ$ for IO. Finally, the effective neutrino mass is $m_{\mathrm{ee}}\in (36.940, 36.980)$ meV for NO and $m_{\mathrm{ee}}\in (76.290, 76.360)$ meV for IO. Based on these results, the Yukawa-like couplings are estimated, which can naturally explain the charged - lepton as well as neutrino mass hierarchies.

We present a novel diagrammatic proof of the identity between the forward matrix element of the energy-momentum-tensor (EMT) trace operator over a single particle's on-shell state and its perturbative pole mass to any loop orders in perturbative gauge theories (with gauge bosons and fermions), without appealing to any pre-laid operator renormalization conditions or Ward identities. The proof is based on the equation of mass-dimensional analysis in dimensional regularization, the topological properties of contributing Feynman diagrams and the on-shell renormalization condition. Considering for definiteness perturbative QED and QCD with at most one fermion kept massive, we have verified the aforementioned identity, up to three loops, for all elementary particles through direct computation of dimensionally-regularized matrix elements of the relevant bare operators. We observe interestingly that the trace-anomaly contribution seemingly contains all leading-renormalon effects (explicitly verified up to three loops), and we propose accordingly a new scheme- and scale-independent trace-anomaly-subtracted mass definition for heavy $t$-,$\,b$-,$\,c$-quarks and electrons. A list of amusing numbers is subsequently presented for the composition of their perturbative pole masses.

We analyse electromagnetic leptogenesis within the framework of an effective field theory, where the dynamics is governed by the gauge-invariant dipole operator $O_{NB}$. The Wilson coefficient $C_{NB}$ is matched at one loop and renormalisation-group (RG) evolved to the electroweak scale. After electroweak symmetry breaking we compute flavour-dependent two-body decay widths and CP asymmetries for $N\to\nu+\gamma/Z$, and solve the fully flavoured Boltzmann equations. In the $N_1$-dominated regime the freeze-out baryon asymmetry is $Y_B^{\rm FO}\lesssim 10^{-17}$, far below the observed value $Y_B^{\rm obs}\simeq 8.7\times 10^{-11}$. The suppression is structural: gauge invariance forces a Higgs insertion; therefore dipole couplings $\mu\propto v/M_{\Psi}^2$ while the matched coefficient $C_{NB}$ is loop-generated and further reduced by RG running. We note that in the quasi-degenerate limit the self-energy resonance can be operative and suggest a plausible path to $Y_B^{\rm obs}$.

We present a light-cone QCD sum rule analysis of the semileptonic decays of $\Xi_c$ baryons, focusing on the channels $\Xi_c^0 \to \Xi^- \ell^+ \nu_\ell$, and $\Xi_c^+ \to \Xi^0 \ell^+ \nu_\ell$. The transition form factors are calculated within the light-cone QCD sum rules framework, using the distribution amplitudes of the heavy $\Xi_c$ baryons. The obtained form factors are then used to compute the differential and total decay widths, as well as the branching fractions. Our numerical results for the branching fractions are $\mathcal{B}(\Xi_c^0 \to \Xi^- \ell^+ \nu_\ell) = (3.73 \pm 1.04)~\%$ , $\mathcal{B}(\Xi_c^0 \to \Xi^- \mu^+ \nu_\mu) = (3.59 \pm 1.01)~\%$, $\mathcal{B}(\Xi_c^+ \to \Xi^0 \ell^+ \nu_\ell) = (11.2 \pm 3.25)~\%$, and $\mathcal{B}(\Xi_c^+ \to \Xi^0 \mu^+ \nu_\mu) = (10.8 \pm 3.13)~\%$. These results are in good agreement with recent lattice QCD calculations, while being larger than the current experimental measurements and differing from the predictions of other theoretical approaches.

Dense QCD matter can feature a moat regime, where the static energy of mesons is minimal at nonzero momentum. Valuable insights into this regime can be gained using low-energy models. This, however, requires a careful assessment of model artifacts. We therefore study the effects of renormalization and in-medium modifications of quark-meson interaction on the moat regime. To capture the main effects, we use a two-flavor quark-meson model at finite temperature and baryon density in the random phase approximation. We put forward a convenient renormalization scheme to account for the nontrivial momentum dependence of meson self-energies and discuss the role of renormalization conditions for renormalization group consistent results on the moat regime. In addition, we demonstrate and that its extent in the phase diagram critically depends on the interaction of quarks and mesons.

Neutrinos are the second most abundant particles in the universe according to the Standard Model, yet they are the least likely to interact. This feature implies that detecting a neutrino can reveal valuable insights into its source. Among the known sources of neutrinos, core-collapse supernovae are one of the most efficient factories. On average, a single collapse occurs every second in the observable universe, emitting approximately $10^{58}$ neutrinos. The total flux of neutrinos reaching Earth from all core-collapse supernovae across the universe is the diffuse supernova neutrino background (DSNB). Detection of the DSNB is just around the corner. This guaranteed flux of astrophysical neutrinos encodes information about the whole supernova population, including an answer to a currently unsolved question about the rate at which black holes form from massive stars. This chapter discusses the ingredients entering the DSNB calculation as well as current experimental limits and hints.

Toward an improved understanding of the role of quantum information in nuclei and exotic matter, we examine the quantum magic (non-stabilizerness) in low-energy strong interaction processes. As stabilizer states can be prepared efficiently using classical computers, and include classes of entangled states, it is quantum magic and fluctuations in quantum magic, together with entanglement, that determine computational resource requirements. As a measure of fluctuations in quantum magic, and hence the severity of the exponentially-scaling classical computing resource requirements, induced by scattering, the "magic power" of the S-matrix is introduced. This provides indirect experimental constraints on quantum resources required to model nuclei and dense matter using fault-tolerant quantum computers. Using experimentally-determined scattering phase shifts and mixing parameters, the magic power in nucleon-nucleon and hyperon-nucleon scattering, along with the magic in the deuteron, are found to exhibit interesting and distinct features. The $\Sigma^-$-baryon is identified as a potential candidate catalyst for enhanced spreading of magic and entanglement in dense matter, depending on in-medium decoherence.

Unlike the duality in four-dimensional spacetime, where the $q-$form fields corresponds to the scalar fields or the vector fields, in higher dimensional spacetime, they denote new types of particles. In this paper, we investigate the localization of the KK modes of the $q$-form fields in a five dimensional brane world. We introduce the coupling between the $q-$form fields and both the gravity and the background scalar field. This consideration enables the localization of the $q$-form fields on the five-dimensional RS-2 thick brane, leading to the derivation of zero modes, Schrödinger-like equations, and a four-dimensional effective action. We suggest a new function $F(R,\varphi)$ to stand for the coupling of the $q$-form field with gravity and background scalar fields. Our analysis highlights the significance of the parameters $\text C_2$ and $\displaystyle t$ in the localization processes.

The LHeC is the project for delivering electron-nucleon collisions at CERN using the HL-LHC beams. An Energy Recovery Linac in racetrack configuration will provide 50 GeV electrons to achieve centre-of-mass energies around 1 TeV/nucleon and instantaneous luminosities around $10^{34}$ cm$^{-2}$s$^{-1}$. The LHeC program elaborated in the CDR of 2021 included a phase with concurrent operation of electron-hadron and hadron-hadron collisions, followed by a standalone phase of electron-hadron collisions only. In view of the current HL-LHC schedule, in this paper we have examined the possibilities of a program after the regular HL-LHC program with only electron-proton operation. In this operation mode, the LHeC would serve as an impactful bridge project between major colliders at CERN. The standalone physics program comprises electroweak, Higgs, top-quark, BSM and strong-interaction physics. In addition, it empowers the physics analyses at the HL-LHC by retrofitting measurements and searches with significantly more precise knowledge of the proton structure and $\alpha_s$. The accelerator technology deployed in the Energy Recovery Linac for the LHeC is a major stepping-stone for the performance, cost reduction and training for future colliders. The capital investments in the LHeC electron accelerator can be reused in a cost-efficient way as the injector for the FCC-ee. Finally, data from the LHeC are essential to enable the physics potential of any new high-energy hadron collider. The operational plan of 6 years easily fits in the period between two major colliders at CERN. Similar to the LHeC empowering the HL-LHC physics program, the FCC-eh would be an impactful addition to the FCC physics program.

Lorentz-equivariant neural networks are becoming the leading architectures for high-energy physics. Current implementations rely on specialized layers, limiting architectural choices. We introduce Lorentz Local Canonicalization (LLoCa), a general framework that renders any backbone network exactly Lorentz-equivariant. Using equivariantly predicted local reference frames, we construct LLoCa-transformers and graph networks. We adapt a recent approach for geometric message passing to the non-compact Lorentz group, allowing propagation of space-time tensorial features. Data augmentation emerges from LLoCa as a special choice of reference frame. Our models achieve competitive and state-of-the-art accuracy on relevant particle physics tasks, while being $4\times$ faster and using $10\times$ fewer FLOPs.

The properties of satellite halos provide a promising probe for dark matter (DM) physics. Observations have motivated current efforts to explain surprisingly compact DM halos. If DM is not collisionless, but has strong self-interactions, halos can undergo gravothermal collapse, leading to higher densities in the central region of the halo. However, it is challenging to model this collapse phase from first principles. To improve on this, we sought to better understand the numerical challenges and convergence properties of self-interacting dark matter (SIDM) N-body simulations in the collapse phase. Especially, our aim was to better understand the evolution of satellite halos. To do so, we ran SIDM N-body simulations of a low-mass halo in isolation and within an external gravitational potential. The simulation set-up was motivated by the perturber of the stellar stream GD-1. We find that the halo evolution is very sensitive to energy conservation errors, and a SIDM kernel size that is too large can artificially speed up the collapse. Moreover, we demonstrate that the King model can describe the density profile at small radii for the late stages that we have simulated. Furthermore, for our most highly resolved simulation (N = 5x10^7) we have made the data public. It can serve as a benchmark. Overall, we find that the current numerical methods do not suffer from convergence problems in the late collapse phase and provide guidance on how to choose numerical parameters, for example that the energy conservation error is better kept well below 1%. This allows simulations to be run of halos that become concentrated enough to explain observations of GD-1-like stellar streams or strong gravitational lensing systems.

In this work, we shall consider how a dynamical oscillating and phantom crossing dark energy era can be realized in the context of $F(R)$ gravity. We approach the topic from a theoretical standpoint considering all the conditions that may lead to a consistent phantom crossing behavior and separately how the $F(R)$ gravity context may realize oscillating dark energy era. Apart from our qualitative considerations, we study in a quantitative way two $F(R)$ gravity dark energy models which are viable cosmologically and also exhibit simultaneously phantom crossing behavior and also oscillating dark energy. We consider these models by solving numerically the field equations using appropriate statefinder parameters engineered for dark energy studies. As we show, $F(R)$ provides a natural extension of Einstein's general relativity which can naturally realize a transition from a phantom era to a quintessential era, a feature supported by recent observational data, without resorting to phantom scalar fields to realize the phantom evolution.

The search for the chiral magnetic effect (CME) in relativistic heavy-ion collisions (HICs) is challenged by significant background contamination. We present a novel deep learning approach based on a U-Net architecture to time-reversely unfold the dynamics of CME-related charge separation, enabling the reconstruction of the physics signal across the entire evolution of HICs. Trained on the events simulated by a multi-phase transport model with different cases of CME settings, our model learns to recover the charge separation based on final-state transverse momentum distributions at either the quark-gloun plasma freeze-out or hadronic freeze-out. This devises a methodological tool for the study of CME and underscores the promise of deep learning approaches in retrieving physics signals in HICs.

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.