Tue·Apr 16, 2024Tuesday·April 16, 2024

1. 01*

   A complete analysis of the Landau-gauge three-gluon vertex from lattice QCD

   F. Pinto-Gómez🇪🇸 · F. De Soto🇪🇸 · J. Rodríguez-Quintero🇪🇸

   Several continuum and lattice investigations of the QCD three-gluon vertex have recently exposed its key properties, some intimately connected with the low-momentum behavior of the two-point gluon Green's function and specially relevant for the emergence of a mass scale in this latter, via the Schwinger mechanism. In the present study, we report on a lattice determination of the Landau-gauge, transversely projected three-gluon vertex, particularly scrutinizing an outstanding one of these properties, termed planar degeneracy, exploring its implications and capitalizing on it to gain further insight on the low-momentum running of both the three-gluon vertex and its associated strong coupling.

   hep-phhep-latPRD(2024)·15 citations
2. 02*

   Hidden BPS states of electroweak monopole and a new bound estimate

   A. Gunawan🇮🇩 · H.S. Ramadhan🇮🇩 · I. Prasetyo🇮🇩

   Using the BPS Lagrangian method, we obtain a distinct set of Bogomolny equations for the Cho-Maison monopoles from the bosonic sector of a regularized electroweak theory. In the limit of $n\to \infty$ of the permittivity regulator, $ϵ\left({\rho }^n\right)$, the mass of the monopole can be estimated to be $M_W\sim 3.56$ TeV. This value is within the latest theoretical window, 2.98 TeV - 3.75 TeV. We also discuss some possible regularization mechanisms of electroweak monopole in the Yang-Mills sector and the existence of its BPS state.

   hep-phhep-thEPJC(2024)·1 citation
3. 03*

   Study of transport properties of a hot and dense QCD matter using a novel approximation method

   Anowar Shaikh🇮🇳 · Shubhalaxmi Rath🇨🇱 · Sadhana Dash🇮🇳 · Binata Panda🇮🇳

   We have studied the charge and the heat transport properties of a hot and dense QCD matter by solving the relativistic Boltzmann transport equation using a novel approximation method. Following the recently developed novel relaxation time approximation (RTA) model, we have proposed a novel Bhatnagar-Gross-Krook (BGK) model with a modified collision integral to carry out the aforementioned study. We have also compared our findings with the results of the novel RTA, the standard RTA and the standard BGK models. Our observation shows that the novel collision integrals for both the RTA and BGK models decrease the charge and the heat transport phenomena in the medium, as evidenced by the reduced values of the transport coefficients, such as the electrical conductivity and the thermal conductivity, when compared to the standard RTA and standard BGK models. Furthermore, certain observables, such as the thermal diffusion constant and the Lorenz number have been explored using the novel approaches of the aforesaid models. We have found an overall decreasing trend of the thermal diffusion constant with the temperature in the novel BGK model, similar to the novel RTA model, but the magnitude remains higher throughout the temperature range. However, the magnitude of the thermal diffusion constant in the proposed novel BGK model remains lower than its value in the standard BGK model. The magnitude of the Lorenz number in the novel BGK model remains higher than that in the standard BGK model, but it is lower than that in the novel RTA model. We have also observed that the Lorenz number in all cases has an increasing trend at low temperatures, showing a violation of the Wiedemann-Franz law, whereas at high temperatures, it becomes saturated. The Lorenz number remaining above unity indicates that the thermal conductivity prevails over the electrical conductivity in the aforesaid models.

   hep-phhep-thnucl-thJ.Phys.G(2025)·4 citations
4. 04*

   Analysis of the L3 BEC at Z${}^0$-pole -- Comparison of the conventional formula against the $\tau$-model

   Takuya Mizoguchi🇯🇵 · Seiji Matsumoto🇯🇵 · Minoru Biyajima🇯🇵

   The L3 Collaboration reported data on 2-jet and 3-jet Bose--Einstein correlations (BECs) with the results obtained through the $\tau$-model in 2011. In this study, we analyze these correlations using the conventional formula with the Gaussian long-range correlation ($\mathrm{C}{\mathrm{F}}_{\mathrm{I}}\times \mathrm{LR}{\mathrm{C}}_{(\mathrm{Gauss})}$). The estimated ranges of interactions for 2-jet and 3-jet, $R_{2-\mathrm{jet}}$ and $R_{3-\mathrm{jet}}$, are almost the same magnitude as those by $\tau$-model: $R_{2-\mathrm{jet}}=0.83\pm 0.05$ (stat) fm and $R_{3-\mathrm{jet}}=1.09\pm 0.04$ (stat) fm. The anticorrelation in BEC (less than 1.0) observed by the L3 Collaboration is related to the partially negative density profile (${\rho }_{\tau ,\mathrm{BE}}(\xi )$ in $\xi$ space) in the $\tau$-model and the $\mathrm{LR}{\mathrm{C}}_{(\mathrm{Gauss})}=1/(1+\alpha e^{-\beta Q^2})$ in $\mathrm{C}{\mathrm{F}}_{\mathrm{I}}\times \mathrm{LR}{\mathrm{C}}_{(\mathrm{Gauss})}$, respectively. Remarkably, the probability $P_{\tau }(\xi )$ calculated from the Levy canonical form exhibits partially negative behavior.

   hep-phInt.J.Mod.Phys.A(2025)·0 citations
5. 05*

   Next-to-leading-order relativistic and QCD corrections to prompt $\mathbf{J}/\mathbf{\psi }$ pair photoproduction at future ${\mathbf{e}}^{+}{\mathbf{e}}^{-}$ colliders

   Zhi-Guo He🇨🇳 · Xiao-Bo Jin🇨🇳 · Bernd A. Kniehl🇩🇪 · Rong Li🇨🇳

   Within the framework of nonrelativistic-QCD factorization, we calculate both the next-to-leading-order relativistic and QCD corrections to prompt $J/\psi$ pair production, with feeddown from $\psi (2S)$ mesons, via photon-photon collisions at future $e^{+}{e}^{-}$ colliders including the Future Circular Lepton Collider (FCC-ee), the Circular Electron Positron Collider (CEPC), and the Compact Linear Collider (CLIC). We present total cross sections and distributions in single $J/\psi$ transverse momentum and rapidity, and in $J/\psi$ pair invariant mass. The relativistic and QCD corrections both turn out to be large and negative. Yet, the production rates are large enough for useful experimental studies.

   hep-phCPC(2024)·5 citations
6. 06*

   Mass spectrum of fully charmed $[cc][\bar{c}\bar{c}]$ tetraquarks

   You-You Lin🇨🇳 · Ji-Ying Wang🇨🇳 · Ailin Zhang🇨🇳

   There are three $S$ and seven $P$ fully charmed $[cc][\bar{c}\bar{c}]$ tetraquarks, the mass spectrum from $1S$ to $2P$ excitations is calculated in a non-relativistic quark potential model. In the calculation, the interactions among four internal quarks/antiquark are approximated as a dominant color interaction between a diquark and an antidiquark, and a residual interaction responsible for the diquark/antidiquark cluster effect. The color interaction between the diquark and the antidiquark is characterized by the conventional Cornell potential, while the residual interaction is modeled as the Yukawa-type scalar $\sigma$ and vector $\omega$ boson exchange potentials. In the numerical results, though the scalar $\sigma$ and vector $\omega$ boson exchange interactions reduce the masses of $S-$wave $[cc][\bar{c}\bar{c}]$ tetraquarks $40-50$ MeV, they contribute to the masses of other $[cc][\bar{c}\bar{c}]$ tetraquarks small. The mass splittings of $[cc][\bar{c}\bar{c}]$ tetraquarks between different multiplets and within the same multiplet are smaller than those in charmonium, and the splittings are affected by the scalar $\sigma$ or vector $\omega$ boson exchange interactions small. Our calculations suggest that the observed $X(6600)$, $X(6900)$ and $X(7300)$ should be different radial excitations of $[cc][\bar{c}\bar{c}]$. The measurements of the $J^{PC}$ quantum numbers and the mass splittings will be helpful to identify and understand of the $[cc][\bar{c}\bar{c}]$ candidates.

   hep-phhep-exEur.Phys.J.Plus(2024)·12 citations
7. 07*

   QCD sum rules for positive and negative parity heavy baryons at next-to-leading order in ${\alpha }_s$-expansion

   Tetsuo Nishikawa🇯🇵 · Yoshihiko Kondo🇯🇵 · Yoshiko Kanada-En'yo🇯🇵

   QCD sum rules for positive and negative parity heavy baryons in the heavy quark limit are formulated. We apply the method to $\Lambda$ and $\Sigma$ channels. We include the next-to-leading order corrections in ${\alpha }_s$-expansion to dimension 0 and 3 terms in the operator product expansion. The corrections lead to the considerable reduction of the predicted masses and significantly improves the stability with respect to the Borel parameter, especially for negative parity states. It is also found that in the heavy quark limit chiral odd condensates do not contribute to the negative parity states.

   hep-phPRD(2024)·2 citations
8. 08*

   Is Doublet-Triplet Splitting Necessary?

   Ilja Doršner🇭🇷 · Shaikh Saad🇨🇭

   We demonstrate that it is not necessary to substantially break the mass degeneracy between the Standard Model Higgs boson doublet and the corresponding scalar leptoquark, where these two fields comprise a single five-dimensional $SU(5)$ representation. More precisely, we show that the experimental data on partial proton decay lifetimes cannot place any meaningful bound on the mass of the scalar leptoquark, a.k.a. the color triplet, if one includes effects of higher-dimensional operators within the Georgi-Glashow model. We also point out that the complete suppression of proton decay via the scalar leptoquark mediation is compatible with the partial suppression of the gauge mediated two-body proton decay signatures. Finally, we derive a proper limit on the cutoff scale of the aforementioned higher-dimensional operators and outline how this scenario could be tested.

   hep-phPRD(2024)·11 citations
9. 09*

   Review on Axions

   Andreas Ringwald🇩🇪

   This proceedings' contribution explores the rationale behind the axion as a resolution to the strong CP puzzle. It outlines various benchmark axion models and examines their implications, focusing on two key aspects: (i) the axion's interactions with the Standard Model particles, and (ii) its potential role as dark matter. Additionally, it provides an overview of the discovery prospects associated with ongoing and future axion experiments. These efforts span from laboratory-based endeavors aimed at directly producing and detecting axions to searches for solar axions, and finally, to the direct detection of axion dark matter.

   hep-phJ.Phys.Conf.Ser.(2025)·31 citations
10. 10*

    Heavy Particle Towers and Nonlocal QFT

    Stathes Paganis🇹🇼

    A number of gravitation-motivated theories, as well as theories with new coloured fermions predict heavy particle towers with spectral densities $\rho (m^2)$ growing faster than $e^m$, a characteristic of nonlocalizable theories. It is shown that if a light scalar, like the Higgs boson, interacts strongly with a heavy scalar particle tower with exponentially rising degeneracy, then the local low-energy theory is equivalent to an effective nonlocal scalar QFT. For energies approaching the nonlocality scale $p^2\simeq {\Lambda }_{NL}^2$, the scalar propagator and scattering amplitudes are modified by nonlocal factors of the form $e^{p^2/{\Lambda }_{NL}^2}$. The double-Higgs production measurement at the LHC is proposed as a highly sensitive probe of nonlocality at the electroweak scale.

    hep-ph2 citations
11. 11*

    Light single-gluon hybrid states with various (exotic) quantum numbers

    Wei-Han Tan🇨🇳 · Niu Su🇨🇳 · Hua-Xing Chen🇨🇳

    We apply the QCD sum rule method to study the light single-gluon hybrid states with various (exotic) quantum numbers. We construct twenty-four single-gluon hybrid currents, and use eighteen of them to calculate the masses of forty-four single-gluon hybrid states with the quark-gluon contents $\bar{q}qg$ ($q=u/d$) and $\bar{s}sg$. We concentrate on the hybrid states with the exotic quantum number $J^{PC}=1^{-+}$, whose masses and widths are calculated to be $M_{|\bar{q}qg;1^{-}{1}^{-+}⟩}=1.67_{-0.17}^{+0.15}$ GeV, ${\Gamma }_{|\bar{q}qg;1^{-}{1}^{-+}⟩}=530_{-330}^{+540}$ MeV, $M_{|\bar{q}qg;0^{+}{1}^{-+}⟩}=1.67_{-0.17}^{+0.15}$ GeV, ${\Gamma }_{|\bar{q}qg;0^{+}{1}^{-+}⟩}=120_{-110}^{+160}$ MeV, $M_{|\bar{s}sg;0^{+}{1}^{-+}⟩}=1.84_{-0.15}^{+0.14}$ GeV, and ${\Gamma }_{|\bar{s}sg;0^{+}{1}^{-+}⟩}=100_{-80}^{+110}$ MeV. Our results support the interpretations of the ${\pi }_1(1600)$ and ${\eta }_1(1855)$ as the hybrid states $|\bar{q}qg;1^{-}{1}^{-+}⟩$ and $|\bar{s}sg;0^{+}{1}^{-+}⟩$, respectively. Considering the uncertainties, our results suggest that the ${\pi }_1(1600)$ and ${\eta }_1(1855)$ may also be interpreted as the hybrid states $|\bar{q}qg;1^{-}{1}^{-+}⟩$ and $|\bar{q}qg;0^{+}{1}^{-+}⟩$, respectively. To differentiate these two assignments and to verify whether they are hybrid states or not, we propose to examine the $a_1(1260)\pi$ decay channel in future experiments.

    hep-phhep-exPRD(2024)·15 citations
12. 12*

    Refined TMD gluon density in a proton from the HERA and LHC data

    A.V. Lipatov🇷🇺 · G.I. Lykasov🇷🇺 · M.A. Malyshev🇷🇺

    We update the phenomenological parameters of the Transverse Momentum Dependent (TMD, or unintegrated) gluon density in a proton proposed in our previous studies. This analysis is based on the analytical expression for starting gluon distribution which provides a self-consistent simultaneous description of HERA data on proton structure function $F_2(x,Q^2)$, reduced cross section for the electron-proton deep inelastic scattering at low $Q^2$ and soft hadron production in $pp$ collisions at the LHC conditions. We extend it to the whole kinematical region using the Catani-Ciafaloni-Fiorani-Marchesini (CCFM) evolution equation. Exploiting our previous results on a number of semihard QCD processes, we performed a combined fit to an extended set of LHC and HERA data, comprising a total of $509$ points from $16$ data sets. We illustrate our fit by applying the derived TMD gluon density in a proton to inclusive prompt photon photoproduction at HERA.

    hep-phJETP Lett.(2024)·6 citations
13. 13*

    Neutrino dipole portal at a high energy $\mu -$collider

    Daniele Barducci🇮🇹 · Alessandro Dondarini🇮🇹

    We study the phenomenology of $d=6$ dipole portal operators connecting active and sterile neutrinos at a futuristic muon collider. These operators can be the dominant portal between the Standard Model and the New Physics sector in scenarios in which the active-sterile mixing is suppressed. We identify two production modes for sterile neutrinos: one proceeding through the exchange of an $s-$channel electroweak boson and one arising from the fusion of an electroweak boson with a Standard Model lepton. We study the expected reach on the operators suppression scale for these different production mechanisms, showing that the latter offers the best sensitivity and allowing to test a New Physics scale in the $\sim 10$TeV range.

    hep-phJHEP(2024)·18 citations
14. 14*

    Indirect constraints on third generation baryon number violation

    Martin Beneke🇩🇪 · Gael Finauri🇩🇪 · Alexey A. Petrov🇺🇸

    The non-observation of baryon number violation suggests that the scale of baryon-number violating interactions at zero temperature is comparable to the GUT scale. However, the pertinent measurements involve hadrons made of the first-generation quarks, such as protons and neutrons. One may therefore entertain the idea that new flavour physics breaks baryon number at a much lower scale, but only in the coupling to a third generation quark, leading to observable baryon-number violating $b$-hadron decay rates. In this paper we show that indirect constraints on the new physics scale ${\Lambda }_{\mathrm{BNV}}$ from the existing bounds on the proton lifetime do not allow for this possibility. For this purpose we consider the three dominant proton decay channels $p\to {\ell }^{+}{\nu }_{\ell }\bar{\nu }$, $p\to {\pi }^{+}\bar{\nu }$ and $p\to {\pi }^0{\ell }^{+}$ mediated by a virtual bottom quark.

    hep-phhep-exJHEP(2024)·12 citations
15. 15*

    Four-loop splitting functions in QCD -- The quark-to-gluon case

    G. Falcioni (Zurich U.)🇨🇭 · F. Herzog (U. Edinburgh, Higgs Ctr. Theor. Phys.)🇬🇧 · S. Moch (Hamburg U., Inst. Theor. Phys. II)🇩🇪 · A. Pelloni (Zurich, ETH)🇨🇭 · A. Vogt (Liverpool U., Dept. Math.)🇬🇧

    We present the even-N moments N =< 20 of the fourth-order (N^3LO) contribution P_{gq}^(3)(x) to the quark-to-gluon splitting function in perturbative QCD. These moments, obtained by analytically computing off-shell operator matrix elements for a general gauge group, agree with all known results, in particular with the moments N =< 10 derived before from structure functions in deep-inelastic scattering. Using the new moments and the available endpoint constraints, we construct approximations for P_{gq}^(3)(x) which improve upon those obtained from the lowest five even moments. The remaining uncertainties of this function are now practically irrelevant at momentum fractions x > 0.1. The resulting errors of the convolution of P_{gq} at N^3LO with a typical quark distribution are small at x >~ 10^{-3} and exceed 1% only at x ~< 10^{-4} for a strong coupling alpha_s = 0.2. The present results for P_{gq}^(3)(x) should thus be sufficient for most collider-physics applications.

    hep-phPLB(2024)·54 citations
16. 16*

    Spatial resolution of dijet photoproduction in near-encounter ultraperipheral nuclear collisions

    Kari J. Eskola🇫🇮 · Vadim Guzey🇫🇮 · Ilkka Helenius🇫🇮 · Petja Paakkinen🇫🇮 · Hannu Paukkunen🇫🇮

    We present next-to-leading order perturbative QCD predictions for inclusive dijet photoproduction in ultra-peripheral nucleus-nucleus collisions (UPCs) within the impact-parameter dependent equivalent photon approximation. Taking into account the finite size of both the photon-emitting and the target nucleus, we show that this process is sensitive to the transverse-plane geometry of the UPC events. We show that this leads to a sizeable, 20-40% effect for large values of the $z_{\gamma }$ variable in the dijet photoproduction cross section in lead-lead UPCs at 5.02 TeV compared to the widely-used pointlike approximation where the nuclear radius is accounted for only as a sharp cut-off in the photon flux calculation. This resolution of the spatial degrees of freedom is a result of having high-transverse-momentum jets in the final state, which at the large-$z_{\gamma }$ kinematics requires a highly energetic photon in the initial state, thus biasing the collisions to small impact-parameter ''near-encounter'' configurations. We further discuss the role of the forward-neutron event-class selection in isolating the photonuclear cross section in the nucleus-nucleus collisions, and employ the needed electromagnetic breakup survival factor in our predictions.

    hep-phPRC(2024)·20 citations
17. 17*

    Electrical conductivity of QGP with quasiparticle quarks and Gribov gluon

    Sadaf Madni🇮🇳 · Sumit🇨🇳 · Lata Thakur🇰🇷 · Najmul Haque🇮🇳

    We investigate the electrical conductivity of the quark-gluon plasma (QGP) using a non-perturbative resummation scheme incorporating the Gribov-modified gluon propagator. The electrical conductivity is evaluated by solving the relativistic Boltzmann transport equation within the relaxation-time approximation, where the relaxation times are obtained from microscopic two-body scattering amplitudes. A quasiparticle description is employed for quarks, providing a unified framework for studying transport properties across both weakly and strongly coupled regimes. Above the deconfinement transition temperature, we estimate the electrical conductivity of the QGP and compare our results with available lattice QCD data and various phenomenological models, finding good agreement with the lattice results.

    hep-phnucl-thEPJC(2026)·10 citations
18. 18*

    Triple Higgs couplings at LHC

    Alain Le Yaouanc🇫🇷 · François Richard🇫🇷

    A global interpretation of several significant indications of scalar resonances observed at LHC is achieved using the Georgi Machacek model. Among many other consequences, one predicts large cross sections for the processes ggFH(320)->h(125)h(125) and A(151)A(151) and ggF->A(420)->H(320)Z, where H(320) has been observed in A(420)->H(320)Z->bbbbl+l- and where A(151) is observed into two photons accompanied by a b jet, a lepton or missing transverse energy. We predict that ggF->H(320) has a cross section of about 2000 fb with a BR into h(125)(125) of 17% and into A(151)A(151) of 45%. Henceforth we predict that ggF->H(320)->hh will dominate over the SM process h*->hh, where h is the SM h(125) scalar. One expects that H(320)->A(151)A(151) can be observed into bbbb, becoming one of the most significant BSM phenomena identified so far. Arguments in favor of a SUSY version of GM are also provided.

    hep-phhep-ex1 citation
19. 19*

    A machine learning-based study of open-charm hadrons in proton-proton collisions at the Large Hadron Collider

    Kangkan Goswami🇮🇳 · Suraj Prasad🇮🇳 · Neelkamal Mallick🇮🇳 · Raghunath Sahoo🇮🇳 · Gagan B. Mohanty🇮🇳

    n proton-proton and heavy-ion collisions, the study of charm hadrons plays a pivotal role in understanding the QCD medium and provides an undisputed testing ground for the theory of strong interaction, as they are mostly produced in the early stages of collisions via hard partonic interactions. The lightest open-charm, $D^0$ meson ($c\text{Bar}u$), can originate from two separate sources. The prompt $D^0$ originates from either direct charm production or the decay of excited open charm states, while the nonprompt stems from the decay of beauty hadrons. In this paper, using different machine learning (ML) algorithms such as XGBoost, CatBoost, and Random Forest, an attempt has been made to segregate the prompt and nonprompt production modes of $D^0$ meson signal from its background. The ML models are trained using the invariant mass through its hadronic decay channel, i.e., $D^0\to {\pi }^{+}{K}^{-}$, pseudoproper time, pseudoproper decay length, and distance of closest approach of $D^0$ meson, using PYTHIA8 simulated $pp$ collisions at $\sqrt{s}=13\mathrm{TeV}$. The ML models used in this analysis are found to retain the pseudorapidity, transverse momentum, and collision energy dependence. In addition, we report the ratio of nonprompt to prompt $D^0$ yield, the self-normalized yield of prompt and nonprompt $D^0$ and explore the charmonium, $J/\psi$ to open-charm, $D^0$ yield ratio as a function of transverse momenta and normalized multiplicity. The observables studied in this manuscript are well predicted by all the ML models compared to the simulation.

    hep-phhep-exhep-thnucl-ex+1PRD(2024)·18 citations
20. 20*

    Matching Hadronization and Perturbative Evolution: The Cluster Model in Light of Infrared Shower Cutoff Dependence

    André H. Hoang🇦🇹 · Oliver L. Jin🇦🇹 · Simon Plätzer🇦🇹 · Daniel Samitz🇦🇹

    In the context of Monte Carlo (MC) generators with parton showers that have next-to-leading-logarithmic (NLL) precision, the cutoff $Q_0$ terminating the shower evolution should be viewed as an infrared factorization scale so that parameters or non-perturbative effects of the MC generator may have a field theoretic interpretation with a controllable scheme dependence. This implies that the generator's parton level should be carefully defined within QCD perturbation theory with subleading order precision. Furthermore, it entails that the shower cut $Q_0$ is not treated as one of the generator's tuning parameters, but that the tuning can be carried out reliably for a range of $Q_0$ values and that the hadron level description is $Q_0$-invariant. This in turn imposes non-trival constraints on the behavior of the generator's hadronization model, so that its parameters can adapt accordingly when the $Q_0$ value is changed. We investigate these features using the angular ordered parton shower and the cluster hadronization model implemented in the Herwig~7.2 MC generator focusing in particular on the $e^{+}{e}^{-}$ 2-jettiness distribution, where the shower is known to be NLL precise and where QCD factorization imposes stringent constraints on the hadronization corrections. We show that the Herwig default cluster hadronization model does not exhibit these features or consistency with QCD factorization with a satisfying precision. We design a modification of the cluster hadronization model, where some dynamical parton shower aspects are added that are missing in the default model. For this novel dynamical cluster hadronization model these features and consistency with QCD factorization are realized much more accurately.

    hep-phhep-exJHEP(2025)·20 citations
21. 21*

    Next-to-Next-to-Leading Order QCD Corrections to Polarized Semi-Inclusive Deep-Inelastic Scattering

    Saurav Goyal🇮🇳 · Roman N. Lee🇷🇺 · Sven-Olaf Moch🇩🇪 · Vaibhav Pathak🇮🇳 · Narayan Rana🇮🇳 · V. Ravindran🇮🇳

    Polarized semi-inclusive deep-inelastic scattering (SIDIS) is a key process in the quest for a resolution of the proton spin puzzle. We present the complete results for the polarized SIDIS process at next-to-next-to-leading order (NNLO) in perturbative quantum chromodynamics. Our analytical results include all partonic channels for the scattering of polarized leptons off hadrons and a spin-averaged hadron identified in the final state. A numerical analysis of the NNLO corrections illustrates their significance and the reduced residual scale dependence in the kinematic range probed by the future Electron-Ion-Collider EIC.

    hep-phhep-exPRL(2024)·37 citations
22. 22*

    Neutrino and Gamma-Ray Signatures of Inelastic Dark Matter Annihilating outside Neutron Stars

    Javier F. Acevedo🇺🇸 · Joseph Bramante🇨🇦 · Qinrui Liu🇨🇦 · Narayani Tyagi🇨🇦

    We present a new inelastic dark matter search: neutron stars in dark matter-rich environments capture inelastic dark matter which, for interstate mass splittings between about $45-285\mathrm{MeV}$, will annihilate away before becoming fully trapped inside the object. This means a sizable fraction of the dark matter particles can annihilate while being outside the neutron star, producing neutron star-focused gamma-rays and neutrinos. We analyze this effect for the first time and target the neutron star population in the Galactic Center, where the large dark matter and neutron star content makes this signal most significant. Depending on the assumed neutron star and dark matter distributions, we set constraints on the dark matter-nucleon inelastic cross-section using existing H.E.S.S. observations. We also forecast the sensitivity of upcoming gamma-ray and neutrino telescopes to this signal, which can reach inelastic cross-sections as low as $\sim 2\times 10^{-47}\mathrm{c}{\mathrm{m}}^2$.

    hep-phastro-ph.HEJCAP(2025)·30 citations
23. 23*

    Theoretical predictions for $b\to s{\mu }^{+}{\mu }^{-}$ decays

    Nico Gubernari🇬🇧

    I review the state of the art of the theoretical calculations for decays mediated by $b\to s{\ell }^{+}{\ell }^{-}$ transitions, for $\ell =e,\mu$. I focus on the predictions of observables in $B\to K{\mu }^{+}{\mu }^{-}$, $B\to K^{\ast }{\mu }^{+}{\mu }^{-}$, and $B_s\to \varphi {\mu }^{+}{\mu }^{-}$ decays, as many of these predictions are in tension with the corresponding experimental measurements. I also briefly discuss the ${\Lambda }_b\to \Lambda {\mu }^{+}{\mu }^{-}$ decay and present a new calculation for this channel. Special emphasis is placed on the non-local contributions, as they are the largest systematic uncertainties in these decays. The current theoretical calculations for $b\to s{\mu }^{+}{\mu }^{-}$ decays are not able to explain the tensions with the experimental measurements.

    hep-phhep-ex2 citations
24. 24*

    Analysis of QCD at finite isospin density: on the relationship between quark degrees of freedom in hadrons and equation of state

    Ryuji Chiba🇯🇵

    We investigate the quark contribution to the equation of state (EOS) of the isospin QCD matter using the two-flavor quark meson model at finite isospin density. This model includes the quark degrees of freedom through the lowest order of the loop correction. This model describes the crossover of the pion condensate from the Bose-Einstein condensation (BEC) phase at low density to the Bardeen-Cooper-Schrieffer (BCS) phase at high density. In the absence of the quark degrees of freedom the pion condensate behaves as the bosonic object, but the quark substructure becomes important and suppress the pion condensate by Pauli blocking as density increase. As the isospin density increases, the EOS rapidly becomes stiff and approaches to the quark matter even before pion starts to overlap. Consequently, the sound velocity exceeds the conformal value $c_s^2=1/3$, forming a peak structure and then relax to the conformal value from above at high density. This is in good agreement with the recent lattice QCD (LQCD) result. In contrast, the perturbative QCD (pQCD) result suggests that the sound velocity approaches to the conformal value from below. This discrepancy comes from the non-perturbative effects arising from the pion condensate or the quark-antiquark correlation near the Fermi surface in the quark meson model. We also investigated the trace anomaly as another measure of conformality. The effects of finite temperature on sound velocity were also examined. On the isentropic trajectory, where $s/n_I$ is fixed, the thermal quarks were found to suppress the sound velocity and smear out the peak structure. The thermal mesons are considered to be important at zero density from LQCD, which is confirmed in this model calculation. The analysis is further extended to the condensed phase at high density, where it is found that thermal mesons do not significantly contribute to the EOS.

    hep-phnucl-th0 citations
25. 25*

    Enumerating 6D supergravities with $T\le 1$

    Yuta Hamada🇯🇵 · Gregory J. Loges🇯🇵

    The space of 6D supergravities with minimal supersymmetry is greatly constrained by anomaly cancellation. Nevertheless, a large number of models satisfy all low-energy consistency conditions and in this work we make progress towards exhaustively enumerating all anomaly-free models with at most one tensor multiplet. Generalizing previous techniques, we describe a general algorithm using multi-hypergraphs and simplicial complexes to systematically enumerate anomaly-free models with gauge groups of any number of simple factors and with hypermultiplets falling into any representations. Using these new ideas, we obtain a \emph{complete} list of anomaly-free models for $T\le 1$, the only simplifying assumption being that the gauge group contains no $U(1)$, $\mathrm{SU}(2)$, $\mathrm{SU}(3)$ or $\mathrm{Sp}(2)$ factors. We also study how many/which models in this ensemble satisfy several UV and swampland bounds which have been proposed and previously utilized to great effect, finding that none are ruled out for $T=0$ and $\approx 50\%$ are inconsistent with quantum gravity for $T=1$.

    ↳ hep-thhep-phJHEP(2024)·14 citations
26. 26*

    Status of Electromagnetic Accelerating Universe

    Paul H. Frampton🇮🇹

    To describe the dark side of the Universe, we adopt a novel approach where dark energy is explained as an electrically charged majority of dark matter. Dark energy, as such, does not exist. The Friedmann equation at the present time coincides with that in a conventional approach, although the cosmological "constant" in the Electromagnetic Accelerating Universe (EAU) Model shares a time dependence with the matter component. Its equation of state is $\omega \equiv P/\rho \equiv -1$ within observational accuracy.

    ↳ gr-qcastro-ph.COastro-ph.HEhep-phPoS(2025)·2 citations
27. 27*

    Analysis of the CERN-NA63 radiation reaction data set, assuming the Rindler bath is composed of microscopic black holes

    Morgan H. Lynch🇰🇷

    In this manuscript we examine the Unruh-thermalized CERN-NA63 radiation reaction data set from the point of view of a diphoton Rindler bath. Under the assumption that these Hawking-Unruh diphoton pairs are microscopic trans-Planckian black holes, we find the resultant heat capacity describes the measured energy spectrum and is thus a dual description of the data set. Then, employing an n-dimensional Stefan-Boltzmann analysis, we find the power radiated by a black hole in the standard 3+1 spacetime dimensions in complete agreement with the data. Finally, we utilize this power spectrum to directly measure Newtons constant of gravitation.

    ↳ gr-qchep-phhep-thPRD(2024)·6 citations
28. 28*

    Linear stability of vector Horndeski black holes

    Che-Yu Chen🇯🇵 · Antonio De Felice🇯🇵 · Shinji Tsujikawa🇯🇵

    Horndeski's vector-tensor (HVT) gravity is described by a Lagrangian in which the field strength $F_{\mu \nu }={\partial }_{\mu }{A}_{\nu }-{\partial }_{\nu }{A}_{\mu }$ of a vector field $A_{\mu }$ interacts with a double dual Riemann tensor $L^{\mu \nu \alpha \beta }$ in the form $\beta L^{\mu \nu \alpha \beta }{F}_{\mu \nu }{F}_{\alpha \beta }$, where $\beta$ is a constant. In Einstein-Maxwell-HVT theory, there are static and spherically symmetric black hole (BH) solutions with electric or magnetic charges, whose metric components are modified from those in the Reissner-Nordström geometry. The electric-magnetic duality of solutions is broken even at the background level by the nonvanishing coupling constant $\beta$. We compute a second-order action of BH perturbations containing both the odd- and even-parity modes and show that there are four dynamical perturbations arising from the gravitational and vector-field sectors. We derive all the linear stability conditions associated with the absence of ghosts and radial/angular Laplacian instabilities for both the electric and magnetic BHs. These conditions exhibit the difference between the electrically and magnetically charged cases by reflecting the breaking of electric-magnetic duality at the level of perturbations. In particular, the four angular propagation speeds in the large-multipole limit are different from each other for both the electric and magnetic BHs. This suggests the breaking of eikonal correspondence between the peak position of at least one of the potentials of dynamical perturbations and the radius of photon sphere. For the electrically and magnetically charged cases, we elucidate parameter spaces of the HVT coupling and the BH charge in which the BHs without naked singularities are linearly stable.

    ↳ gr-qchep-phhep-thJCAP(2024)·11 citations
29. 29*

    Cosmological Correlators with Double Massive Exchanges: Bootstrap Equation and Phenomenology

    Shuntaro Aoki🇰🇷 · Lucas Pinol🇫🇷 · Fumiya Sano🇯🇵 · Masahide Yamaguchi🇯🇵 · Yuhang Zhu🇰🇷

    Using the recently developed cosmological bootstrap method, we compute the exact analytical solution for the seed integral appearing in cosmological correlators with double massive scalar exchanges. The result is explicit, valid in any kinematic configuration, and free from spurious divergences. It is applicable to any number of fields' species with any masses. With an appropriate choice of variables, the results contain only single-layer summations. We also propose simple approximate formulas valid in different limits, enabling direct and instantaneous evaluation.Supported by exact numerical results using CosmoFlow, we explore the phenomenology of double massive exchange diagrams. Contrary to single-exchange diagrams with ubiquitous Lorentz-covariant interactions, the size of the cubic coupling constant can be large while respecting perturbativity bounds. Because of this property, the primordial bispectrum from double-exchange diagrams can be as large as, coincidentally, current observational constraints. In addition to being sizable on equilateral configurations, we show that the primordial bispectrum exhibits a large cosmological collider signal in the squeezed limit, making the double massive exchanges interesting channels for the detection of massive primordial fields. We propose to decisively disentangle double-exchange channels from single-exchange ones with cosmological observations by exploiting the phase information of the cosmological collider signal, the inflationary flavor oscillations from multiple fields' species exchanges and the double soft limit in the primordial trispectrum.

    ↳ hep-thastro-ph.COgr-qchep-phJHEP(2024)·54 citations
30. 30*

    First search for light fermionic dark matter absorption on electrons using germanium detector in CDEX-10 experiment

    J. X. Liu🇨🇳 · L. T. Yang🇨🇳 · Q. Yue🇨🇳 · K. J. Kang🇨🇳 · Y. J. Li🇨🇳 · H. P. An🇨🇳 · Greeshma C.🇹🇼 · J. P. Chang🇨🇳 · Y. H. Chen🇨🇳 · J. P. Cheng🇨🇳 · W. H. Dai🇨🇳 · Z. Deng🇨🇳 and 74 other authors

    We present the first results of the search for sub-MeV fermionic dark matter absorbed by electron targets of germanium using the 205.4~kg$\cdot$day data collected by the CDEX-10 experiment, with the analysis threshold of 160~eVee. No significant dark matter (DM) signals over the background are observed. Results are presented as limits on the cross section of DM--electron interaction. We present new constraints of cross section in the DM range of 0.1--10 keV/$c^2$ for vector and axial-vector interaction. The upper limit on the cross section is set to be $6.8\times 10^{-46}\mathrm{c}{\mathrm{m}}^2$ for vector interaction, and $2.3\times 10^{-46}\mathrm{c}{\mathrm{m}}^2$ for axial-vector interaction at DM mass of 5 keV/$c^2$.

    ↳ hep-exhep-phphysics.ins-detPRD(2026)·12 citations
31. 31*

    The NICER data and a $\sigma$-field dependent stiffness of the hadronic equation of state

    E. E. Kolomeitsev🇷🇺 · D. N. Voskresensky🇷🇺

    Analyses for the NICER data indicate that there is no significant variation of the compact star radii within the mass range of 1.4 to 2.0 solar masses. Yamamoto et al. [Phys. Rev. C 108, 035811 (2023)] concluded recently that ``this feature cannot be reproduced by the hadronic matter due to the softening of the equation of state (EoS) by hyperon mixing, suggesting the possible existence of quark phases in neutron-star interiors.'' Using a collection of 162 purely nucleonic, hyperonic, and quarkish EoSs from CompOSE database and some other works, we verify that hyperons indeed lead to a significant difference in radii of stars of 1.4 and 2.0 solar masses, which diminishes in the presence of quarks. We compare the shapes of the mass-radius curves and show that hyperons and quarks in the neutron star cores prefer a particular curve shape with backbending. It is argued that the shape {is controlled by the density dependence} of the nuclear symmetry energy. We draw attention to the existence of a class of purely hadronic relativistic mean-field EoSs with scalar-field dependent hadron masses and coupling constants that satisfy the known constraints on the EoSs including the analyses of the new NICER data and the above requirement of no significant variation of the neutron star radii.

    ↳ nucl-thastro-ph.HEhep-phPRC(2024)·7 citations
32. 32*

    Effects of Superradiance in Active Galactic Nuclei

    Priyanka Sarmah🇹🇼 · Himanshu Verma🇮🇳 · Kingman Cheung🇹🇼 · Joseph Silk🇫🇷

    A supermassive black hole (SMBH) at the core of an active galactic nucleus (AGN) provides room for the elusive ultra-light scalar particles (ULSP) to be produced through a phenomenon called \textit{superradiance}. This phenomenon produces a cloud of scalar particles around the black hole by draining its spin angular momentum. In this work, we present a study of the superradiant instability due to a scalar field in the vicinity of the central SMBH in an AGN. We begin by showing that the time-evolution of the gravitational coupling $\alpha$ in a realistic ambiance created by the accretion disk around the SMBH in AGN leads to interesting consequences such as the amplified growth of the scalar cloud, enhancement of the gravitational wave emission rate, and appearance of higher modes of superradiance within the age of the Universe. We then explore the consequence of superradiance on the characteristics of the AGN. Using the Novikov-Thorne model for an accretion disk, we divide the full spectrum into three wavelength bands- X-ray ($10^{-4}-10^{-2}\mu$m), UV (0.010-0.4~$\mu$m), and Vis-IR (0.4-100~$\mu$m) and observe sudden drops in the time-variations of the luminosities across these bands and Eddington ratio ($f_{\text{Edd}}$) with a characteristic timescale of superradiance. Using a uniform distribution of spin and mass of the SMBHs in AGNs, we demonstrate the appearance of depleted regions and accumulations along the boundaries of these regions in the planes of different band-luminosities and $f_{\text{Edd}}$. Finally, we discuss some possible signatures of superradiance that can be drawn from the observed time-variation of the AGN luminosities.

    ↳ astro-ph.HEhep-phMNRAS(2025)·16 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.