New articles on High Energy Physics - Phenomenology

[1] 2312.00806

Accessing CKM suppressed top decays at the LHC

We present an strategy for measuring the off-diagonal elements of the third row of CKM matrix $|V_{tq}|$ through the branching fractions of top quark decays $t\to q W$, where $q$ is a light quark jet. This strategy is an extension of existing measurements, with the improvement rooted in the use of orthogonal $b$- and $q$-taggers that add a new observable, the number of light-quark-tagged jets, to the already commonly used observable, the fraction of $b$-tagged jets in an event. Careful inclusion of the additional complementary observable significantly increases the expected statistical power of the analysis, with the possibility of excluding a null $|V_{td}|^2+|V_{ts}|^2$ at $95\%$ C.L. at the HL-LHC.

[2] 2312.00809

Off-shell modifications of bound nucleons and parton distributions

We discuss results from our global QCD analyses including nuclear data off deuterium from various measurements, as well as off $^3$H and $^3$He targets from the MARATHON experiment. We simultaneously determine the parton distribution functions of the proton, the higher-twist terms, and the nucleon off-shell correction functions responsible for the modifications of the partonic structure in bound protons and neutrons. In particular, we study the neutron-proton asymmetry of the off-shell correction and its interplay with the treatment of the higher-twist terms. We observe that the data on the $^3$He/$^3$H cross section ratio are consistent with a single isoscalar off-shell function. We also provide our predictions on the ratio $F_2^n/F_2^p$ and on the $d$ and $u$ quark distributions in the proton and in the $^3$H and $^3$He nuclei.

[3] 2312.00814

Dark Matter Interpretation of Neutron Multiplicity Anomalies

Subterrestrial neutron spectra show weak but consistent anomalies at multiplicities ~100 and above [1-3]. The data of the available measurements are of low statistical significance [4] but indicate an excess of events not correlated with the muon flux. The origin of the anomalies remains ambiguous but could be a signature of WIMP annihilation-like interaction with a Pb target. In this paper, we outline a model consistent with this hypothesis, the extended Standard Model (SM) approach called the Radiation Gauge Model (RGM) [5]. The RGM identifies scalar neutrino-antineutrino wave function components of WIMP Dark Matter (DM) responsible for the weak interaction leading to annihilation with ordinary matter. The model assigns neutrino-nucleon(target) charged current (CC) transitions to the observed anomalies. If the existence of the anomalies is confirmed and the model interpretation is positively verified, this will be the first terrestrial indirect detection of DM.

[4] 2312.00822

$M_{W_R}$ dependence of leptogenesis in Minimal Left-Right Symmetric Model with different strengths of Type-II seesaw mass

Left Right Symmetric Model (LRSM) being an extension of the Standard model of particle physics incorporates within itself Type-I and Type-II seesaw mass terms naturally. Both the mass terms can have significant amount of contribution to the resulting light neutrino mass within the model and hence on the different phenomenology associated within. In this paper, we have thoroughly analyzed and discussed the implications of specifying different weightages to the type-I and type-II mass terms and also the study has been carried out for different values of $M_{W_R}$ which is mass of the right-handed gauge boson. This paper also gives a deeper insight into the new physics contributions of Neutrinoless Double Beta Decay $(0\nu\beta\beta)$ and their variations with the net baryon asymmetry arising out of the model. Therefore, the main objective of the present paper rests on investigating the implications of imposing different weightage to the type-I and type-II seesaw terms and different values of $M_{W_R}$ on the new physics contributions of $0\nu\beta\beta$ and net baryon asymmetry arising out as a result of resonant leptogenesis. LRSM in this work has been realized using modular group of level 3, $\Gamma(3)$ which is isomorphic to non-abelian discrete symmetry group $A_4$, the advantage being the non-requirement of flavons within the model and hence maintaining the minimality of the model.

[5] 2312.00861

Soft-gluon corrections in $t{\bar t}W$ production

We study higher-order QCD corrections for the associated production of a top-antitop quark pair and a $W$ boson ($t{\bar t}W$ production) in proton-proton collisions. We calculate approximate NNLO (aNNLO) and approximate N$^3$LO (aN$^3$LO) cross sections, with second-order and third-order soft-gluon corrections added to the exact NLO QCD result, and we also include electroweak (EW) corrections through NLO. We calculate uncertainties from scale dependence, which are reduced at higher orders, and from parton distributions, and we also provide separate results for $t{\bar t}W^+$ and $t{\bar t}W^-$. We compare our results to recent measurements from the LHC, and we find that the aN$^3$LO QCD + NLO EW predictions provide improved agreement with the data. We also calculate differential distributions in top-quark transverse momentum and rapidity and find significant enhancements from the higher-order corrections.

[6] 2312.00866

Sub-MeV Dark Matter Detection with Bilayer Graphene

After decades of effort in a number of dark matter direct detection experiments, we still do not have any conclusive signal yet. Therefore it is high time we broaden our horizon by building experiments with increased sensitivity for light dark matter, specifically in the sub-MeV mass regime. In this paper, we propose a new detector material, a bilayer stack of graphene for this purpose. Its voltage-tunable low energy sub-eV electronic band gap makes it an excellent choice for the detector material of a light dark matter search experiment. We compute its dielectric function using the random phase approximation and estimate the projected sensitivity for sub-MeV dark matter-electron scattering and sub-eV dark matter absorption. We show that a bilayer graphene dark matter detector can have competitive sensitivity as other candidate target materials, like a superconductor, in this mass regime. The dark matter scattering rate in bilayer graphene is also characterized by a daily modulation from the rotation of the Earth which may help us mitigate the backgrounds in a future experiment.

[7] 2312.00872

Precise tests of the axion coupling to tops

We present an in-depth analysis of axions and axion-like particles in top-pair production at the LHC. Our main goal is to probe the axion coupling to top quarks at high energies. To this end, we calculate the top-antitop cross section and differential distributions including ALP effects up to one-loop level. By comparing these predictions with LHC precision measurements, we constrain the top coupling of axion-like particles with masses below the top-antitop threshold. Our results apply to all UV completions of the ALP effective theory with dominant couplings to top quarks, in particular to DFSZ-like axion models.

[8] 2312.00881

Walls, bubbles and doom -- the cosmology of HEFT

As experiment charts new territory at the electroweak scale, the enterprise to characterise all possible theories becomes all the more necessary. In the absence of new particles, this ambitious enterprise is attainable and has led to the Higgs Effective Field Theory (HEFT) as the most general characterising framework, containing the Standard Model Effective Field Theory (SMEFT) as a subspace. The characterisation of this theory space led to the dichotomy SMEFT vs. HEFT\SMEFT as the two possible realisations of symmetry breaking. The criterion to distinguish these two possibilities is non-local in field space, and phenomena which explore field space beyond the neighbourhood of the vacuum manifold are in a singular position to tell them apart. Cosmology allows for such phenomena, and this work focuses on HEFT\SMEFT, the less explored of the two options, to find that first order phase transitions with detectable gravitational wave remnants, domain wall formation and vacuum decay in the far, far distant future can take place and single out HEFT\SMEFT. Results in cosmology are put against LHC constraints, and the potential of future ground- and space-based experiments to cover parameter space is discussed.

[9] 2312.00882

Maximising CP Violation in Naturally Aligned Two-Higgs Doublet Models

The Two-Higgs Doublet Model (2HDM) is a well-motivated theoretical framework that provides additional sources of CP Violation (CPV) beyond the Standard Model (SM). After studying the vacuum topology of the general 2HDM potential, we unambiguously identify three origins of CPV: (I) Spontaneous CPV (SCPV), (ii) Explicit CPV (ECPV) and (iii) Mixed Spontaneous and Explicit CPV (MCPV). In all these scenarios, only two CPV phases can be made independent, as any third CPV parameter will always be constrained via the CP-odd tadpole condition. Since ECPV vanishes in 2HDMs where SM Higgs alignment is achieved naturally through accidental continuous symmetries, we analyse the possibility of maximising CPV through soft and explicit breaking of these symmetries. We derive upper limits on key CPV parameters that quantify the degree of SM misalignment from constraints due to the non-observation of an electron Electric Dipole Moment (EDM). Finally, we delineate the CP-violating parameter space of the so-constrained naturally aligned 2HDMs that can further be probed at the CERN Large Hadron Collider (LHC).

[10] 2312.00982

Higgs Portal Interpretation of the Belle II $B^+ \to K^+ νν$ Measurement

The Belle II experiment recently observed the decay $B^+ \to K^+ \nu \nu$ for the first time, with a measured value for the branching ratio of $ (2.3 \pm 0.7) \times 10^{-5}$. This result exhibits a $\sim 3\sigma$ deviation from the Standard Model (SM) prediction. The observed enhancement with respect to the Standard Model could indicate the presence of invisible light new physics. In this paper, we investigate whether this result can be accommodated in a minimal Higgs portal model, where the SM is extended by a singlet Higgs scalar that decays invisibly to dark sector states. We find that current and future bounds on invisible decays of the 125 GeV Higgs boson completely exclude a new scalar with a mass $\gtrsim 10$ GeV. On the other hand, the Belle II results can be successfully accommodated if the new scalar is lighter than $B$ mesons but heavier than kaons. We also investigate the cosmological implications of the new states and explore the possibility that they are part of an abelian Higgs extension of the SM. Future Higgs factories are expected to place stringent bounds on the invisible branching ratio of the 125 GeV Higgs boson, and will be able to definitively test the region of parameter space favored by the Belle II results.

[11] 2312.01008

Explore the Nucleon Tomography through Di-hadron Correlation in Opposite Hemisphere in Deep Inelastic Scattering

We investigate the correlation of di-hadron productions between the current fragmentation region (CFR) and target fragmentation region (TFR) in deep inelastic scattering as a probe of the nucleon tomography. The QCD factorization and powering counting method are applied to compute the relevant diffractive parton distribution functions in the valence region. In particular, we show that the final state interaction effects lead to a nonzero longitudinal polarized quark distribution associated with the unpolarized nucleon target. This explains the observed beam single spin asymmetry (BSA) from a recent Jefferson Lab experiment. We further show that the BSA in the single diffractive hadron productions in the TFR, although kinematically suppressed, also exists because of the final state interaction effects.

[12] 2312.01013

Coupling constants of the $σ$ meson to the ground state octet baryons

Based on the one-boson-exchange framework that the $\sigma$ meson serves as an effective parameterization for the correlated scalar-isoscalar $\pi\pi$ interaction, we calculate the coupling constants of the $\sigma$ to the $\frac{1}{2}^+$ ground state light baryon octet ${\mathbb B}$ by matching the amplitude of ${\mathbb B}\bar{{\mathbb B}}\to\pi\pi\to\bar{{\mathbb B}}{\mathbb B}$ to that of ${\mathbb B}\bar{\mathbb B}\to\sigma\to\bar{{\mathbb B}}{\mathbb B}$. The former is calculated using a dispersion relation, supplemented with chiral perturbation theory results for the ${\mathbb B}{\mathbb B}\pi\pi$ couplings and the Muskhelishvili-Omn\`es representation for the $\pi\pi$ rescattering. Explicitly, the coupling constants are obtained as $g_{NN\sigma}=8.7_{-1.1-1.3}^{+1.3+1.1}$, $g_{\Sigma\Sigma\sigma}=3.6_{-1.1-0.4}^{+1.8+0.4}$, $g_{\Xi\Xi\sigma}=2.5_{-1.3-0.6}^{+1.4+0.5}$, and $g_{\Lambda\Lambda\sigma}=6.8_{-1.0-1.4}^{+1.0+1.1}$. These coupling constants can be used in the one-boson-exchange model calculations of the interaction of light baryons with other hadrons.

[13] 2312.01173

$P$-wave states $T^-_{bb}$ from diquarks

We investigate the $P$-wave states $T^-_{bb}$ in the isospin singlet and three excited modes (excitation occurring in the diquark $[bb]^{s_1}_{c_1}$ ($\rho_1$-mode), antidiquark $[\bar{u}\bar{d}]^{s_2}_{c_2}$ ($\rho_2$-mode) or between them ($\lambda$-mode)) from diquarks in a quark model. We analyse the dynamical behaviors of the diquark $[bb]^{s_1}_{c_1}$, antidiquark $[\bar{u}\bar{d}]^{s_2}_{c_2}$ and their correlations in the states $T^-_{bb}$ by decomposing the interactions from various sources in the model. The absolute dominant color-spin configuration, more than $99\%$, in the $\rho_1$-mode with $1^1P_1$ is $[bb]^0_{\bar{\mathbf{3}}}[\bar{u}\bar{d}]^0_{\mathbf{3}}$. Its energy is lower about $18$ MeV than the threshold $\bar{B}\bar{B}$ so that it can establish a compact bound state. The chromomagnetic and meson-exchange interactions in the antidiquark $[\bar{u}\bar{d}]^0_{\mathbf{3}}$ are responsible for its binding mechanism. Other two excited modes are higher than their respective threshold.

[14] 2312.01309

Probing quark orbital angular momentum at EIC and EicC

We propose to extract quark orbital angular momentum (OAM) through exclusive $\pi^0$ production in electron-(longitudinally-polarized) proton collisions. Our analysis demonstrates that the $\sin 2\phi$ azimuthal angular correlation between the transverse momentum of the scattered electron and the recoil proton serves as a sensitive probe of quark OAM. Additionally, we present a numerical estimate of the asymmetry associated with this correlation for the kinematics accessible at EIC and EicC. This study aims to pave the way for the first measurement of quark OAM in relation to the Jaffe-Manohar spin sum rule.

[15] 2312.01332

The electromagnetic properties of the $T^+_{cc}$ molecular states

In this work, we discuss the electromagnetic properties of the $S$-wave and $D$-wave $T^+_{cc}$ molecular states, which include the magnetic moments, transition magnetic moments and radiative decay widths. According to our results, the magnetic moment of $T^+_{cc}$ state observed experimentally is $-0.09\mu_N$. Meanwhile, we also discuss the relations between the transition magnetic moments of the $S$-wave $T^+_{cc}$ molecular states and the radiative decay widths, and we analyze the proportionality between the magnetic moments of the $T^+_{cc}$ molecular states. These results provide further information on the inner structure of $T^+_{cc}$ molecular states and deepen the understanding of electromagnetic properties of doubly charmed tetraquarks.

[16] 2312.01346

A holographic study on QCD phase transition and phase diagram with two flavors

We investigate the chemical potential effects of the equation of state and the chiral transition in an Einstein-Maxwell-dilaton-scalar system, which is obtained from an improved soft-wall AdS/QCD model coupled with an Einstein-Maxwell-dilaton system. The equations of state obtained from the model are in quantitative agreement with the lattice results at both zero and nonzero chemical potentials. The sensible chiral transition behaviors can be realized in the model. The QCD phase diagram with a CEP has also been obtained from the model.

[17] 2312.01355

The electroweak magnetic monopole in the presence of KSVZ axion

The Witten effect implies the dynamics of axion and magnetic monopole. The Cho-Maison monopole is a realistic electroweak monopole arisen in the Weinberg-Salam theory. This monopole of TeV scale mass motivates the dedicated search for electroweak monopole at colliders. In this work we investigate the implication of KSVZ axion to the electroweak magnetic monopole. We use the spherically symmetric ansatz for the electroweak dyon and introduce the spherically symmetric function for the axion field. The effective Lagrangian is then shown in terms of the electroweak monopole part, the axion kinetic energy as well as the axion interaction term. We derive the consequent equations of motion in the presence of the axion-photon coupling and show the numerical results of the topological solutions. We then calculate the changed characteristics of the electroweak monopole such as the monopole mass and the electromagnetic charges, as well as the axion potential energy.

[18] 2312.01365

Temperature and volume dependence of pion-pion scattering lengths

The s-wave pion-pion scattering lengths $ a_0 $ and $ a_2 $ are studied at finite temperature and in finite spatial volume under the framework of the Nambu--Jona-Lasinio model. With the proper time regularization, the behavior beyond the pseudo transition temperature is presented. The scattering length $ a_0$ shows singularity near the Mott temperature and $ a_2$ is a continuous but non-monotonic function of temperature. We present the finite volume effect on the scattering length and have found that $a_0$ can be negative and its singularity disappears at small volume size which may hint the existence of chiral phase transition as volume decreases.

[19] 2312.01373

Approximate N$^5$LO Higgs boson decay width $Γ(H\toγγ)$

The precision and predictive power of perturbative QCD (pQCD) prediction depends on both a precise, convergent fixed-order series and a reliable way of estimating the contributions of unknown higher-order (UHO) terms. It has been shown that by applying the Principal of Maximum Conformality (PMC), which applies the renormalization group equation recursively to set the effective magnitude of $\alpha_s$ of the process, the remaining conformal coefficients will be well matched with the corresponding $\alpha_s$ at each orders, leading to a scheme-and-scale invariant and convergent perturbative series. Thus different from conventional scheme-and-scale dependent fixed-order series, the PMC series will provide a more reliable platform for estimating UHO contributions. In this paper, by using the total decay width $\Gamma(H\to\gamma\gamma)$ which has been calculated up to N$^4$LO QCD corrections, we derive its PMC series by using the PMC single-scale setting approach and estimate its unknown N$^5$LO contributions by using the Bayesian analysis. The Bayesian-based approach estimates the magnitude of the UHO contributions based on an optimized analysis of probability density distribution, and the predicted UHO contribution becomes more accurate when more loop terms have been known to tame the probability density function. Using the top-quark pole mass $M_t$=172.69 GeV and the Higgs mass $M_H$=125.25 GeV as inputs, we obtain $\Gamma(H\to\gamma\gamma) =9.56504~{\rm keV}$ and the estimated N$^5$LO contribution to the total decay width is $\Delta\Gamma_H=\pm1.65\times10^{-4}~{\rm keV}$ for the smallest credible interval of $95.5\%$ degree-of-belief.

[20] 2312.01380

Flavor symmetries in the leptonic Yukawa sector of the 3HDM

As an extension of the Standard Model (SM), the 3HDM (Three-Higgs-Doublet Model) defines additional relationships among the fermions. In the visible leptonic Yukawa sector of a minimal 3HDM, we determine and classify the existing flavor symmetries under discrete non-abelian groups up to order 1032. The three Higgs doublets form a flavor triplet, and the admission of unfaithful representations enriches the set of candidate flavor transformations greatly. The many existing symmetries give rise (after EWSB) to a large number of inequivalent mass matrices that imply lepton properties, which in turn are evaluated against experimental data. In the 3HDM the mass hierarchy of the charged leptons leads to a too small $\Delta m^2_{21} / \Delta m^2_{32}$ ratio of the neutrinos. More generally, it is proven that the lepton mass matrices implied by discrete flavor symmetries are in disagreement with the observed data for all groups investigated, both when it is assumed that the neutrinos have the Dirac or Majorana nature.

[21] 2312.01422

Testing Gravity and Predictions Beyond the Standard Model at Short Distances: The Casimir Effect

The Standard Model of elementary particles and their interactions does not include the gravitational interaction and faces problems in understanding of the dark matter, dark energy, strong CP violation etc. In continuing attempts to solve these problems, many predictions of new light elementary particles and hypothetical interactions beyond the Standard Model have been made. These predictions can be constrained by many means and, specifically, by measuring the Casimir force arising between two closely spaced bodies due to the zero-point and thermal fluctuations of the electromagnetic field. After a brief survey in the theory of the Casimir effect, the strongest constraints on the power-type and Yukawa-type corrections to Newtonian gravity, following from measuring the Casimir force at short distances, are considered. Next,the problems of dark matter, dark energy and their probable constituents are discussed. This is followed by an analysis of constraints on the dark matter particles, and, specifically, on axions and axionlike particles, obtained from the Casimir effect. The question of whether the Casimir effect can be used for constraining the spin-dependent interactions is also considered. Then the constraints on the dark energy particles, like chameleons and symmetrons, are examined. In all cases the subject of our treatment is not only measurements of the Casimir force but some other relevant table-top experiments as well. In conclusion, the prospects of the Casimir effect for constraining theoretical predictions beyond the Standard Model at short distances are summarized.

[22] 2312.01433

Productions of $D^*_{s0}(2317)$ and $D_{s1}(2460)$ in $B_{(s)}$ and $Λ_b(Ξ_b)$ decays

Recent studies show that $D_{s0}^{\ast}(2317)$ and $D_{s1}(2460)$ contain large molecular components. In this work, we employ the naive factorization approach to calculate the production rates of $D_{s0}^{\ast}(2317)$ and $D_{s1}(2460)$ as hadronic molecules in $B_{(s)}$ and $\Lambda_b(\Xi_b)$ decays, where their decay constants are estimated in the effective Lagrangian approach. With the so-obtained decay constants $f_{D_{s0}^{\ast}(2317)}$ and $f_{D_{s1}(2460)}$, we calculate the branching fractions of the $b$-meson decays $B_{(s)}\to \bar{D}_{(s)}^{(*)}D_{s0}^*$ and $B_{(s)}\to \bar{D}_{(s)}^{(*)}D_{s1}$ and the $b$-baryon decays $\Lambda_b(\Xi_{b}) \to \Lambda_c(\Xi_{c}) D_{s0}^*$ and $\Lambda_b(\Xi_{b}) \to \Lambda_c(\Xi_c) D_{s1}$. Our results show that the production rates of $D_{s0}^{\ast}(2317)$ and $D_{s1}(2460)$ in the $B_s$, $\Lambda_b$ and $\Xi_b$ decays are rather large that future experiments could observe them. In particular, we demonstrate that one can extract the decay constants of hadronic molecules via the triangle mechanism because of the equivalence of the triangle mechanism to the tree diagram established in calculating the decays $B \to \bar{D}^{(*)}D_{s0}^{\ast}(2317)$ and $B \to \bar{D}^{(*)}D_{s1}(2460)$.

[23] 2312.01458

Differential $eμbb $ Cross-Sections and New Higgses at the Electroweak Scale

ATLAS found that none of their Standard Model simulations can describe the measured differential lepton distributions in their $t \bar{t}$ analysis reasonably well. Therefore, we study the possibility that this measurement has a new physics contamination. We consider a benchmark model motivated by the indications for di-photon resonances: A heavy scalar decays into two lighter Higgs bosons with masses of 152\,GeV and 95\,GeV, with subsequent decay to $WW$ and $bb$, respectively. In this setup, the description of data is improved by at least $5.6 \sigma$.

[24] 2312.01470

ee$\in$MC: Low Energy Mesons and the Residual QCD Potential

The Flux-Tube Breaking Model in ee$\in$MC is expanded to include the residual QCD potential between the Final-State mesons, within the non-relativistic limit. These residual QCD potentials have been predicted in the context of the Flux-Tube Breaking Models to generate meson-meson molecular states for the $f_{0}(500)$, $f_{0}(980)$, $a_{0}(980)$, through the colour hyper-fine spin-spin interaction. These residual potentials are also found to have an important impact on the $S_{1}$ decay of the $a_{1}$ and $K_{1}$ axial-vector mesons due to the colour hyper-fine spin-spin interaction. It is found that in the low mass regions, the $\rho(770)$ and $K^{*}(892)$ are sensitive to the linear-confining potential and colour-Coulomb potential suggesting that with the high statistics at the B-Factories, it may be possible to probe the linear-confining potential and colour-Coulomb potential through a model dependent description of the resonance shape or by exploiting multiple production process.

[25] 2312.01484

Flavor asymmetry of light sea quarks in proton : A light-front spectator model

We formulate a light-front spectator model for the proton that incorporates the presence of light sea quarks. In this particular model, the sea quarks are seen as active partons, whereas the remaining components of the proton are treated as spectators. The proposed model relies on the formulation of the light-front wave function constructed by the soft wall AdS/QCD. The model wave functions are parameterized by fitting the unpolarized parton distribution functions of light sea quarks from the CTEQ18 global analysis. We then employ the light-front wave functions to obtain the sea quarks generalized parton distribution functions, transverse momentum dependent parton distributions, and their asymmetries, which are accessible in the upcoming Electron-Ion-Colliders. We investigate sea quarks' spin and orbital angular momentum contributions to the proton spin.

[26] 2312.01525

$Z_3$ symmetry of the CKM and PMNS matrices

We develop for the CKM and PMNS matrices a new representation with special properties. It is obtained by splitting each of these matrices into two rotations by the angle ${\sim}2\pi/3$ and a universal diagonal matrix with elements, which are cubic roots of~1. Such a representation of the CKM and PMNS matrices may indicate the $Z_{3}$ symmetry to be present in the Yukawa sector of the~SM. Identical mathematical structure of the CKM and PMNS matrices is also an extension of the quark-lepton universality. In this approach the CP violation is a natural consequence of the structure of the Yukawa couplings. The CP violating phase is not a fitted parameter and its value is governed by the parameters of two rotations. The parameters of the diagonalizing matrices of the bi-unitary transformation do not exhibit a hierarchy, which means that the origins of the hierarchy of quark masses and of the CKM matrix elements are not the same.

[27] 2312.01594

Impact of the LZ Experiment on DM Phenomenology and Naturalness in the MSSM

Taking the bino-dominated dark matter (DM) as an example, through approximate analytical formulas and numerical results, this paper analyzes impact of the LUX-ZEPLIN (LZ) Experiment on DM phenomenology and naturalness in Minimal Super-symmetric Standard Model(MSSM). It concluded that under the limitation of the latest LZ experiment, MSSM suffers unattractive fine-tunings. The reason is that the latest LZ experiment results improve $\mu$ bounds, e.g., for the cases of the Z- or h-mediated resonant annihilations to achieve the measured dark matter density, the LZ experiment require $\mu$ should be larger than about $500~{\rm GeV}$ or TeV magnitude, which imply a tuning to predict the $Z$-boson mass and simultaneously worsen the naturalness of the $Z$- and $h$-mediated resonant annihilations to achieve the measured dark matter density.

[28] 2312.01621

Simple Lévy-$α$ stable model analysis of elastic $pp$ and $p\bar p$ low-$|t|$ data from SPS to LHC energies

A simple L\'evy-$\alpha$ stable (SL) model is used to describe the data on elastic $pp$ and $p\bar p$ scattering at low-$|t|$ from SPS energies up to LHC energies. The SL model is demonstrated to describe the data with a strong non-exponential feature in a statistically acceptable manner. The energy dependence of the parameters of the model is determined and analyzed. The L\'evy $\alpha$ parameter of the model has an energy-independent value of 1.959 $\pm$ 0.002 following from the strong non-exponential behavior of the data. We strengthen the conclusion that the discrepancy between TOTEM and ATLAS elastic $pp$ differential cross section measurements shows up only in the normalization and not in the shape of the distribution of the data as a function of $t$. We find that the slope parameter has different values for $pp$ and $p\bar p$ elastic scattering at LHC energies. This may be the effect of the odderon exchange or the jump in the energy dependence of the slope parameter in the energy interval 3 GeV $\lesssim \sqrt s \lesssim$ 4 GeV.

[29] 2312.01693

Chiral perturbative evaluation for the (second) lightest mass $M_{1,2}$ of right-handed neutrino $ν_{R 1,2}$ in unified theories with sequential dominance

In this paper, we evaluate the (second) lightest mass $M_{1,2}$ of right-handed neutrino $\nu_{R1,2}$ in grand unified theories with the type-I seesaw mechanism that predicts an almost massless neutrino $m_{1 \, \rm or \, 3} \sim 0$. By chiral perturbative treatment, the masses $M_{1,2}$ are expressed as $M_{1} = m_{D1}^{2}/m_{11} , \, M_{2} = m_{D2}^{2} m_{11} / (m_{11} m_{22} - m_{12}^{2})$ with the mass matrix of left-handed neutrinos $m$ in the diagonal basis of the Dirac mass matrix $m_{D}$. Assuming $m_{Di}$ and the unitary matrix $V$ in the singular value decomposition $(m_{D})_{ij} = V_{ik} m_{D k} U^{\dagger}_{kj}$ are close to observed fermion masses and the CKM matrix, $M_{1,2}$ and their allowed regions are expressed by parameters in the low energy and unknown phases. As a result, for $m_{D1} \simeq 0.5$ MeV and $m_{D2} \simeq 100$ MeV, we obtain $M_{1}^{\rm NH} \simeq 3 \times 10^{4 - 6}$ GeV and $M_{2}^{\rm NH} \simeq 3 \times 10^{6-8}$ GeV in the NH, $M_{1}^{\rm IH} \simeq 5 \times 10^{3 - 4}$ GeV and $M_{2}^{\rm IH} \simeq 4 \times 10^{8-9}$ GeV in the IH. These upper and lower bounds are proportional to $m_{Di}^{2}$ or $m_{D1} m_{D2}$.

[30] 2312.01703

Test of vector portal with dark fermions in the charge-exchange reactions in the NA64 experiment at CERN SPS

We consider an experiment to search for dark sector particles in dark photon kinetic mixing model by analyze invisible and semi-invisible decays of neutral mesons $M^0 = \pi^0$, $\eta$, $\eta'$, $\omega$, $f_2(1270)$, produced in the NA64 experiment at the CERN SPS. The approach proposed in Ref.~\cite{Gninenko:2014sxa} is to use the charge-exchange reactions $\pi^- + (A, Z) \to M^0 + (A,Z-1); M^0 \to$ invisible or semi-invisible of high-energy pions (or kaons) at a nuclei target as a source of $M^0$s, which subsequently decay invisibly into dark sector. This reaction chain would lead to a striking signature of the signal event - the complete disappearance of the beam energy in the setup. Using data obtained from the study of charge-exchange reactions at IHEP (Protvino) and Fermilab (Batavia) we show that the integral cross sections $\sigma$ for production of the neutral mesons $M^0$ are slightly deviate from phenomenological formula $\sigma \sim Z^{2/3}$, where $Z$ is the nuclei charge. In particular, we present the formulas for the differential and integral sections that explicitly depend on the Mandelstam and $Z$ variables. Derived formulas are used to predict the cross sections as a function of beam energy for several target nuclei, and to estimate the projection sensitivity for the proposed search for the $M^0\to$ semi-invisible and $M^0\to$ invisible decays through the vector portal to dark sector. Sensitivity to different semi-invisible decay modes of neutral pseudoscalar mesons is studied.

[31] 2312.01718

Type-II Seesaw Leptogenesis along the Ridge

Type-II seesaw leptogenesis is a model that integrates inflation, baryon number asymmetry, and neutrino mass simultaneously. It employs the Affleck-Dine mechanism to generate lepton asymmetry, with the Higgs bosons serving as the inflaton. Previous studies assumed inflation to occur in a valley of the potential, employing the single-field approximation. In this work, we explore an alternative scenario for the type-II seesaw leptogenesis, where the inflation takes place along a ridge of the potential. Firstly, we conduct a comprehensive numerical calculation in the canonical scenario, where inflation occurs in a valley, confirming the effectiveness of the single-field approximation. Then, we introduce a novel scenario wherein inflation initiates along the potential's ridge and transitions to the valley in the late stages. In this case, the single-field inflation approximation is no longer valid, yet leptogenesis is still successfully achieved. We find that this scenario can generate a significant non-Gaussianity signature, offering testable predictions for future experiments.

[32] 2312.01799

$J/ψ$ polarization in relativistic heavy ion collisions

Understanding the polarization property of $J/\psi$ is critical to constrain its production mechanism. In addition, the polarization of $J/\psi$ can reveal the impact of strong electromagnetic and vorticity fields in relativistic heavy ion collisions. In this study, we analyzed the yield and polarization of $J/\psi$ in relativistic heavy ion collisions at different centrality and transverse momentum regions, using three different reference frames: the Collins-Soper frame, the helicity frame, and the event plane frame. The polarization of initially produced $J/\psi$ is determined by the NRQCD calculation and is similar to that of $pp$ collisions. However, both unpolarization and transverse polarization are considered for the regenerated $J/\psi$. Our results indicate that the polarization at high $p_T$ is similar to that observed in $pp$ collisions. However, at low $p_T$, where regenerated $J/\psi$ dominates, it is likely that the polarized charm quarks in the rotational QGP medium are responsible for this phenomenon. Our study supplies a baseline for future research on the effects of strong electromagnetic and vorticity fields on $J/\psi$ polarization.

[33] 2312.01908

Triply heavy tetraquark states: mass and other properties

In this work, we study mass and other static properties of triply heavy tetraquarks in the unified framework of the MIT bag which incorporates chromomagnetic interactions and enhanced binding energy. The masses, magnetic moments and charge radii of all strange and nonstrange (ground) states of triply heavy tetraquarks are computed, suggesting that all of triply heavy tetraquarks are above the respective two-meson thresholds. We also estimate relative decay widths of main decay channels of two-heavy mesons for these tetraquarks.

[34] 2312.01989

Strange hidden-charm pentaquark poles from $B^-\to J/ψΛ\bar{p}$

Recent LHCb data for $B^-\to J/\psi\Lambda\bar{p}$ show a clear peak structure at the $\Xi_c\bar{D}$ threshold in the $J/\psi\Lambda$ invariant mass ($M_{J/\psi\Lambda}$) distribution. The LHCb's amplitude analysis identified the peak with the first hidden-charm pentaquark with strangeness $P_{\psi s}^\Lambda(4338)$. We conduct a coupled-channel amplitude analysis of the LHCb data by simultaneously fitting the $M_{J/\psi\Lambda}$, $M_{J/\psi\bar{p}}$, $M_{\Lambda\bar{p}}$, and $\cos\theta_{K^*}$ distributions. Rather than the Breit-Wigner fit employed in the LHCb analysis, we consider relevant threshold effects and a unitary $\Xi_c\bar{D}$-$\Lambda_c\bar{D}_s$ coupled-channel scattering amplitude from which $P_{\psi s}^\Lambda$ poles are extracted for the first time. In our default fit, the $P_{\psi s}^\Lambda(4338)$ pole is almost a $\Xi_c \bar{D}$ bound state at $( 4338.2\pm 1.4)-( 1.9\pm 0.5 )\,i$ MeV. Our default model also fits a large fluctuation at the $\Lambda_c\bar{D}_s$ threshold, giving a $\Lambda_c\bar{D}_s$ virtual state, $P_{\psi s}^\Lambda(4255)$, at $4254.7\pm 0.4$ MeV. We also found that the $P_{\psi s}^\Lambda(4338)$ peak cannot solely be a kinematical effect, and a nearby pole is needed.

[35] 2312.01993

Model parameter optimisation with Bayesian statistics

The accuracy and precision of models are key issues for the design and development of new applications and experiments. We present a method of optimisation for a large variety of models. This approach is designed in order both to improve the accuracy of models through the modification of free parameters of these models, which results in a better reproduction of experimental data, and to estimate the uncertainties of these parameters and, by extension, their impacts on the model output. We discuss the method in detail and present a proof-of-concept for Monte Carlo models.

[36] 2312.02005

Remote sensing of backward reflection from stimulated axion decay

We propose a method for remotely detecting backward reflection via induced decay of cold dark matter such as axion in the background of a propagating coherent photon field. This method can be particularly useful for probing concentrated dark matter streams by Earth's gravitational lensing effect. Formulae for the stimulated reflection process and the expected sensitivities in local and remote experimental approaches are provided for testing eV scale axion models using broad band lasers. The generic axion-photon coupling is expected to be explorable up to ${\cal O}(10^{-12})$ GeV${}^{-1}$ and ${\cal O}(10^{-22})$ GeV${}^{-1}$ for the idealized local and remote setups, respectively.

[37] 2312.02007

Far-from-equilibrium attractors for massive kinetic theory in the relaxation time approximation

In this proceedings contribution, we summarize recent findings concerning the presence of early- and late-time attractors in non-conformal kinetic theory. We study the effects of varying both the initial momentum-space anisotropy and initialization times using an exact solution of the 0+1D boost-invariant Boltzmann equation with a mass- and temperature-dependent relaxation time. Our findings support the existence of a longitudinal pressure attractor, but they do not support the existence of distinct attractors for the bulk viscous and shear pressures. Considering a large set of integral moments, we show that for moments with greater than one power of longitudinal momentum squared, both early- and late-time attractors are present.

[38] 2312.02053

Tensions in $e^+e^-\toπ^+π^-(γ)$ measurements: the new landscape of data-driven hadronic vacuum polarization predictions for the muon $g-2$

The situation of the experimental data used in the dispersive evaluation of the hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon is assessed in view of two recent measurements: $e^+e^- \to \pi^+\pi^-$ cross sections in the $\rho$ resonance region by CMD-3 and a study of higher-order radiative effects in the initial-state-radiation processes $e^+e^- \to \mu^+\mu^-\gamma$ and $e^+e^- \to \pi^+\pi^-\gamma$ by BABAR. The impact of the latter study on the KLOE and BESIII cross-section measurements is evaluated and found to be indicative of larger systematic effects than uncertainties assigned. The new situation also warrants a reappraisal of the independent information provided by hadronic $\tau$ decays, including state-of-the-art isospin-breaking corrections. The findings cast a new light on the longstanding deviation between the muon $g-2$ measurement and the Standard Model prediction using the data-driven dispersive approach, and the comparison with lattice QCD calculations.

[39] 2312.02067

Learning Feynman integrals from differential equations with neural networks

We present a new approach for evaluating Feynman integrals numerically. We apply the recently-proposed framework of physics-informed deep learning to train neural networks to approximate the solution to the differential equations satisfied by the Feynman integrals. This approach relies neither on a canonical form of the differential equations, which is often a bottleneck for the analytical techniques, nor on the availability of a large dataset, and after training yields essentially instantaneous evaluation times. We provide a proof-of-concept implementation within the PyTorch framework, and apply it to a number of one- and two-loop examples, achieving a mean magnitude of relative difference of around 1% at two loops in the physical phase space with network training times on the order of an hour on a laptop GPU.

[40] 2312.02086

Ruling out models of vector dark matter in asymptotically safe quantum gravity

The nature of dark matter is a problem with too many potential solutions. We investigate whether a consistent embedding into quantum gravity can decimate the number of solutions to the dark-matter problem. Concretely, we focus on a hidden sector composed of a gauge field and a charged scalar, with gauge group U(1)$_{\textmd{D}}$ or SU(2)$_\textmd{D}$. The gauge field is the dark-matter candidate, if the gauge symmetry is broken spontaneously. Phenomenological constraints on the couplings in this model arise from requiring that the correct dark matter relic density is produced via thermal freeze-out and that recent bounds from direct-detection experiments are respected. We find that the consistent embedding into asymptotically safe quantum gravity gives rise to additional constraints on the couplings at the Planck scale, from which we calculate corresponding constraints at low energy scales. We discover that phenomenological constraints cannot be satisfied simultaneously with theoretical constraints from asymptotically safe quantum gravity, ruling out these dark-matter models.

[41] 2311.17176

A model-independent tripartite test of cosmic distance relations

Cosmological distances are fundamental observables in cosmology. The luminosity ($D_L$), angular diameter ($D_A$) and gravitational wave ($D_{\rm GW}$) distances are all trivially related in General Relativity assuming no significant absorption of photons in the extragalactic medium, also known as cosmic opacity. Supernovae have long been the main cosmological standard candle for the past decades, but bright standard sirens are now a proven alternative, with the advantage of not requiring calibration with other astrophysical sources. Moreover, they can also measure deviations from modified gravity since they can provide evidence for a discrepancy between $D_L$ and $D_{\rm GW}$. However, both gravitational and cosmological parameters are degenerate in the Hubble diagram, making it hard to properly detect beyond standard model physics. Finally, recently a model-independent method was proposed to infer angular diameter distances from large-scale structure which is independent of both early universe and dark energy physics. In this paper we propose a tripartite test of the ratios of these three distances with minimal amount of assumptions regarding cosmology, the early universe, cosmic opacity and modified gravity. We proceed to forecast this test with a combination of uncalibrated LSST and Roman supernovae, Einstein Telescope bright sirens and a joint DESI-like + Euclid-like galaxy survey. We find that even in this very model-independent approach we will be able to detect, in each of many redshift bins, percent-level deviations in these ratios of distances, allowing for very precise consistency checks of $\Lambda$CDM and standard physics.

[42] 2311.17990

On the IR Divergences in de Sitter Space: loops, resummation and the semi-classical wavefunction

In this paper, we revisit the infrared (IR) divergences in de Sitter (dS) space using the wavefunction method, and explicitly explore how the resummation of higher-order loops leads to the stochastic formalism. In light of recent developments of the cosmological bootstrap, we track the behaviour of these nontrivial IR effects from perturbation theory to the non-perturbative regime. Specifically, we first examine the perturbative computation of wavefunction coefficients, and show that there is a clear distinction between classical components from tree-level diagrams and quantum ones from loop processes. Cosmological correlators at loop level receive contributions from tree-level wavefunction coefficients, which we dub classical loops. This distinction significantly simplifies the analysis of loop-level IR divergences, as we find the leading contributions always come from these classical loops. Then we compare with correlators from the perturbative stochastic computation, and find the results there are essentially the ones from classical loops, while quantum loops are only present as subleading corrections. This demonstrates that the leading IR effects are contained in the semi-classical wavefunction which is a resummation of all the tree-level diagrams. With this insight, we go beyond perturbation theory and present a new derivation of the stochastic formalism using the saddle-point approximation. We show that the Fokker-Planck equation follows as a consequence of two effects: the drift from the Schr\"odinger equation that describes the bulk time evolution, and the diffusion from the Polchinski's equation which corresponds to the exact renormalization group flow of the coarse-grained theory on the boundary.

[43] 2312.01153

CosmiXs: Cosmic messenger spectra for indirect dark matter searches

The energy spectra of particles produced from dark matter (DM) annihilation or decay are one of the fundamental ingredients to calculate the predicted fluxes of cosmic rays and radiation searched for in indirect DM detection. We revisit the calculation of the source spectra for annihilating and decaying DM using the Vincia shower algorithm in Pythia to include QED and QCD final state radiation and diagrams for the Electroweak (EW) corrections with massive bosons, not present in the default Pythia shower model. We take into account the spin information of the particles during the entire EW shower and the off-shell contributions from massive gauge bosons. Furthermore, we perform a dedicated tuning of the Vincia and Pythia parameters to LEP data on the production of pions, photons, and hyperons at the $Z$ resonance and discuss the underlying uncertainties. To enable the use of our results in DM studies, we provide the tabulated source spectra for the most relevant cosmic messenger particles, namely antiprotons, positrons, $\gamma$ rays and the three neutrino flavors, for all the fermionic and bosonic channels and DM masses between 5 GeV and 100 TeV, on

[44] 2312.01259

Topological defect formation in a phase transition with tunable order

The Kibble-Zurek mechanism (KZM) describes the non-equilibrium dynamics and topological defect formation in systems undergoing second-order phase transitions. KZM has found applications in fields such as cosmology and condensed matter physics. However, it is generally not suitable for describing first-order phase transitions. It has been demonstrated that transitions in systems like superconductors or charged superfluids, typically classified as second-order, can exhibit weakly first-order characteristics when the influence of fluctuations is taken into account. Moreover, the order of the phase transition (i.e., the extent to which it becomes first rather than second order) can be tuned. We explore quench-induced formation of topological defects in such tunable phase transitions and propose that their density can be predicted by combining KZM with nucleation theory.

[45] 2312.01485

Strangeness production in double gap events in ALICE

The ALICE detector at the LHC was upgraded in the long shutdown of 2019-2021 in order to take data at much-increased Run 3 and 4 rates. The various challenges of this upgrade are presented, and the first results of strangeness production in double gap events collected in 2022 are shown by presenting distributions of kaon pairs.

[46] 2312.01824

NANOGrav hints for first-order confinement-deconfinement phase transition in different QCD-matter scenarios

Recent observations from several pulsar timing array (PTA) collaborations have unveiled compelling evidence for a stochastic signal in the nanohertz band. This signal aligns remarkably with a gravitational wave (GW) background, potentially originating from the first-order color charge confinement phase transition. Distinct quantum chromodynamics (QCD) matters, such as quarks or gluons, and diverse phase transition processes thereof can yield disparate GW energy density spectra. In this letter, employing the Bayesian analysis on the NANOGrav 15-year data set, we explore the compatibility with the observed PTA signal of the GW from phase transitions of various QCD matter scenarios in the framework of the holographic QCD. We find that the PTA signal can be effectively explained by the GW from the confinement-deconfinement phase transition of pure quark systems in a hard wall model of the holographic QCD where the bubble dynamics, one important source of the GWs, is of the Jouguet detonations. Notably, our analysis decisively rules out the plausibility of the pure gluon QCD-matter scenario and the non-runaway bubble dynamics model for the phase transition in explaining the observed PTA signal.

[47] 2312.01930

Solving the left-hand cut problem in lattice QCD: $T_{cc}(3875)^+$ from finite volume energy levels

A novel effective-field-theory-based approach is implemented for extracting two-body scattering information from finite volume energies, serving as an alternative to L\"uscher's method. By explicitly incorporating one-pion exchange, the approach quantitatively accounts for effects related to left-hand cuts and range corrections from the longest-range interactions. The method utilizes the plane wave basis instead of the conventional partial wave expansion, thereby also naturally including partial wave mixing effects resulting from rotational symmetry breaking in a cubic box. Applied to the lattice data for $DD^*$ scattering at a pion mass of 280 MeV, it reveals the significant impact of the one-pion exchange on P-wave and S-wave phase shifts. The pole position of the $T_{cc}(3875)^+$ state, extracted from the finite-volume energy levels while taking into account left-hand cut effects, range corrections, and partial-wave mixing, appears to be consistent with a near-threshold resonance.

[48] 2312.01975

Thermal twin stars within a hybrid equation of state based on a nonlocal chiral quark model compatible with modern astrophysical observations

We investigate the extension to finite temperatures and neutrino chemical potentials of a recently developed nonlocal chiral quark model approach to the equation of state of neutron star matter. We consider two light quark flavors and current-current interactions in the scalar-pseudoscalar, vector, and diquark pairing channels, where the nonlocality of the currents is taken into account by a Gaussian form factor that depends on the spatial components of the 4-momentum. Within this framework, we analyze order parameters, critical temperatures, phase diagrams, equation of state, and mass-radius relations for different temperatures and neutrino chemical potentials. For parameters of the model that are constrained by recent multi-messenger observations of neutron stars, we find that the mass-radius diagram for isothermal hybrid star sequences exhibits the thermal twin phenomenon for temperatures above 30 MeV.

[49] 2312.02084

Aether-scalar field compactification and Casimir effect

In this study, we explore the impact of an additional dimension, as proposed in Kaluza-Klein's theory, on the Casimir effect within the context of Lorentz invariance violation (LIV), which is represented by the aether field. We demonstrate that the Casimir energy is directly influenced by the presence of the fifth dimension, as well as by the aether parameter. Consequently, the force between the plates is also subject to variations of these parameters. Furthermore, we examine constraints on both the size of the extra dimension and the aether field parameter based on experimental data. The LIV parameter can provide insights into addressing the size-related challenges in Kaluza-Klein's theory and offers a mean to establish an upper limit on the size of the extra dimension. This helps to rationalize the difficulties associated with its detection in current experiments.