Tue·May 6, 2025Tuesday·May 6, 2025

1. 01*

   Leptonic Flavor from Modular $A_4$: UV Mediators and SMEFT Realizations

   Adrián Moreno-Sánchez🇪🇸 · Ajdin Palavrić🇨🇭

   The absence of direct evidence for new physics at current collider energies motivates the study of indirect effects within the framework of the Standard Model Effective Field Theory (SMEFT). In this work, we investigate the role of the $A_4$ discrete flavor symmetry in constraining the UV dynamics, giving rise to dimension-6 SMEFT operators involving leptons. We consider renormalizable interactions between SM fields and heavy mediators, classified according to their $A_4$ transformation properties in the modular framework, where Yukawa structures are encoded in modular forms. Restricting our analysis to UV interactions with at most a single modular form insertion, we study the resulting classification of $A_4$ UV mediator irreps and explore their implications across a range of observables, including both lepton-flavor-conserving and lepton-flavor-violating processes. A detailed phenomenological analysis is carried out, incorporating both tree-level and one-loop matching contributions for scalar and fermionic mediators, as well as leading-log RGE effects in case of vectors.

   hep-phPRD(2025)·13 citations
2. 02*

   Supersymmetry and LHC era

   Hyun Min Lee🇰🇷

   We review the basics of the supersymmetric extension of the Standard Model and discuss the implications of the constraints on the superpartner masses at the LHC for the Higgs mass, the $W$ boson mass, the muon $g-2$ and the proton lifetime.

   hep-phhep-th3 citations
3. 03*

   On the gluon shadowing effect in light and heavy nuclei at small $x$

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

   We propose new Transverse Momentum Dependent (TMD) gluon densities in nuclei. Our method is based on a combination of the color dipole scattering formalism, within which we interpret the nuclear deep inelastic structure functions $F_2^A(x,Q^2)$ and well established property of geometrical scaling from nucleons to nuclei. As an input, we employ the TMD gluon density in a proton which provides a self-consistent simultaneous description of the numerous HERA and LHC data on $pp$, $ep$ and $\gamma p$ processes. After fitting the relevant phenomenological parameters to the experimental data on the ratios $F_2^A(x,Q^2)/F_2^{A^{\prime }}(x,Q^2)$ for several nuclear targets $A$ and $A^{\prime }$, we derive the corresponding nuclear gluon distributions. Then, we make predictions for gluon shadowing effects at small Bjorken $x$ in their dependence of the mass number $A$. A comparison with other approaches is given.

   hep-phPRD(2025)·4 citations
4. 04*

   Probing low scale leptogenesis through gravitational wave

   Anirban Biswas🇮🇳 · Sougata Ganguly🇰🇷

   The quest for a common origin of neutrino mass and baryogenesis is one of the longstanding goals in particle physics. A minimal gauge extension of the Standard Model by $U(1{)}_{\mathrm{B}-\mathrm{L}}$ symmetry provides a unique scenario to explain the tiny mass of neutrinos as well as the observed baryon asymmetry, both by virtue of three right-handed neutrinos (RHNs). Additionally, the $U(1{)}_{\mathrm{B}-\mathrm{L}}$ breaking scalar that generates mass of the RHNs can produce a stochastic gravitational wave background (SGWB) via cosmological first-order phase transition. In this work, we systematically investigate TeV-scale leptogenesis considering flavor effects that are crucial in low temperature regime. We also explore all possible RHN production channels which can have significant impact on the abundance of RHNs, depending on the value of $U(1{)}_{\mathrm{B}-\mathrm{L}}$ gauge coupling. We demonstrate that the strong dependence of $U(1{)}_{\mathrm{B}-\mathrm{L}}$ gauge sector on the baryon asymmetry as well as SGWB production can be utilized to probe a region of the model parameter space. In particular, we find that $U(1{)}_{\mathrm{B}-\mathrm{L}}$ gauge boson with mass $\sim 10\mathrm{TeV}$ and gauge coupling $\sim 0.1$ can explain the observed baryon asymmetry and produces detectable SGWB in future detectors as well. Importantly, this region falls beyond the reach of the current collider sensitivity.

   hep-phPRD(2026)·4 citations
5. 05*

   Phenomenology of $D_{s1}$ mesons radiative transitions

   A.E.Bondar🇷🇺 · A.I.Milstein🇷🇺

   We discuss radiative transitions $D_{s1}\to D_s\gamma$ and $D_{s1}\to D_s^{\ast }\gamma$ of $p$-wave mesons. Since $D_{s1}$ mesons have no a certain $C$-parity, and the masses of quarks in these mesons differ significantly, then due to the spin-orbit interaction each of $p$-wave mesons with the total angular momentum $J=1$ is a superposition of states with the total spin of quarks $S_{tot}=0$ and $S_{tot}=1$. We explain why the partial width of $D_{s1}(2460)\to D_s\gamma$ radiative transition is significantly larger than the corresponding value for $D_{s1}(2536)\to D_s\gamma$. We also predict the corresponding partial widths of $B_{s1}$ and $B_{c1}$.

   hep-phhep-exPRD(2025)·6 citations
6. 06*

   Light dark-matter window constrained by \boldmath$K^{+}\to {\pi }^{+}$$+$$/E$

   Xiao-Gang He🇨🇳 · Xiao-Dong Ma🇨🇳 · Jusak Tandean🇨🇳 · German Valencia🇦🇺

   We explore the constraints on new physics from the recent NA62 observation of the kaon decay $K^{+}\to {\pi }^{+}$+$/E$ with missing energy $/E$ in the context of a dark-matter (DM) scenario recently used to accommodate the Belle II finding of an enhanced rate of the $b$-meson decay $B^{+}\to K^{+}$+$/E$ compared to the standard-model expectation. Specifically, assuming that a light real scalar boson $\varphi$ plays the role of DM and working in an effective field-theory framework, we study model independently the impact of operators involving $\varphi$ and ordinary quarks on the aforementioned transitions over the kaon mode's kinematical mass region of $m_{\varphi }<(m_K-m_{\pi })/2=177$ MeV. Such a DM particle is subject to significant restrictions from the observed relic abundance and from DM direct-detection experiments incorporating the Migdal effect, as well as from indirect searches in cosmic microwave background data and collider experiments, except when its mass is between 110 and 146 MeV. We demonstrate that $K^{+}\to {\pi }^{+}\varphi \varphi$ can saturate the new-physics window in the NA62 result if $m_{\varphi }$ lies in the 110-130 MeV portion of the range left by the DM constraints, thus providing a complementary constraint on this scenario. Improved data from future Belle II and NA62 measurements and DM quests can test it more stringently. In particular, expanding the NA62 signal window into the region that is now removed due to three-body decay background modes could further explore the remaining mass window for this type of invisible particle, $130<m_{\varphi }<177$ MeV.

   hep-phhep-exPRD(2025)·8 citations
7. 07*

   Pseudoscalar Higgs Production at Muon Colliders: The Role of One-Loop Effective Vertices

   Fayez Abu-Ajamieh🇮🇳 · Sagar Modak🇮🇳 · Samadrita Mukherjee🇮🇳 · Sudhir K Vempati🇮🇳

   We investigate the production of the pseudoscalar Higgs boson $A$ at muon colliders within the framework of Type-II and Type-X Two-Higgs-Doublet Model (2HDM) at the Next-to-Leading Order (NLO), utilizing an Effective Field Theory (EFT) approach. In particular, we analyze the level of enhancement to the cross section due to the inclusion of the one-loop corrections involving $\gamma$ and $Z$ boson fusion compared to the tree-level contribution. We find that for Type-II, including the effective vertices of $\gamma \gamma A$, $\gamma ZA$ and $ZZA$, could lead to an enhancement of a factor of $\sim 2$ at low $m_A$ and low $\tan \beta$, whereas for Type-X, the enhancement could reach $\sim 10$ in the same regime. We also investigate the impact of the COM energy and $\tan \beta$ on the production cross section. We find that for the region of the parameter space not excluded by experiment, cross sections of $\gtrsim 1$ fb for Type-II, and $\gtrsim 5$ fb for Type-X, are possible, making the proposed muon collider a feasible alternative for probing the 2HDM extended Higgs sector.

   hep-phhep-ex3 citations
8. 08*

   The Simplest Dark Matter Model at the Edge of Perturbativity

   Miguel Escudero🇨🇭 · Thomas Hambye🇧🇪

   Increasingly sensitive direct detection dark matter experiments are testing important regions of parameter space for WIMP dark matter and pushing many models to the multi-TeV regime. This brings into question the perturbativity of these models. In this context, and in light of the new limits from the LZ experiment, we investigate the status of the simplest thermal dark matter model: a singlet scalar, real or complex, coupled to the Higgs boson. We calculate the next-to-leading order (NLO) corrections to the direct detection rates as well as for the annihilations driving thermal freeze-out. For the complex case, we find that the entire perturbative region is excluded by direct detection. For the real case we find that the mass should be $\gtrsim 20\mathrm{TeV}$ at NLO, compared with the $\gtrsim 30\mathrm{TeV}$ LO limit. We highlight that a three-fold improvement on WIMP spin independent interactions can fully test the real scalar model in the perturbative regime. Finally, for both models, there is still an allowed (albeit narrow) region near the Higgs resonance where couplings are perturbative.

   hep-phastro-ph.COPLB(2025)·13 citations
9. 09*

   Rephasing invariants of CP violation for heavy and light Majorana neutrinos

   Zhi-zhong Xing🇨🇳

   In the canonical seesaw mechanism, the strengths of charged-current interactions for light and heavy Majorana neutrinos are described respectively by the $3\times 3$ matrices $U$ and $R$ that are correlated with each other via the exact seesaw relation and the unitarity condition. We write out the Majorana-type invariants of CP violation of $R$ and $U$, which are insensitive to redefining the phases of three charged-lepton fields; and the Dirac-type invariants of CP violation of $R$ and $U$ that are insensitive to the rephasing of both the charged-lepton fields and the neutrino fields. Such invariants are explicitly calculated with the help of a full Euler-like block parametrization of the seesaw flavor structure containing nine active-sterile flavor mixing angles and six independent CP-violating phases, and their corresponding roles in the CP-violating asymmetries of three heavy Majorana neutrino decays and in the flavor oscillations of three light Majorana neutrinos are briefly discussed. We point out that similar rephasing invariants arising from the interplay between $R$ and $U$ may also manifest themselves in a variety of lepton-flavor-violating and lepton-number-violating processes.

   hep-phhep-exhep-thPLB(2025)·2 citations
10. 10*

    The $\rho$-meson electromagnetic form factors within the light-front quark model

    Shuai Xu🇨🇳 · Xiao-Nan Li🇨🇳 · Xing-Gang Wu🇨🇳

    In this paper, we study the $\rho$-meson electromagnetic form factors (EMFFs) within the framework of light-front quark model (LFQM). The physical form factors $G_{C,M,Q}(Q^2)$ of $\rho$-meson as well as the charged square radius $⟨r^2⟩$, the magnetic moment $\mu$ and the quadrupole moment $\bar{Q}$ are calculated, which describe the behaviors of EMFFs at zero momentum transfer. Using the type-II replacement, we find that the zero-mode does contribute zero to the matrix element $S_{00}^{+}$. It is found that the ``$M\to M_0$" replacement improves angular condition remarkably, which permits different prescriptions of $\rho$-meson EMFFs give the consistent results. The residue tiny violation of angular condition needs other explanations than the zero-mode contributions. Our results indicate that the relativistic effects or interaction internal structure are weaken in the zero-binding limit. This work is also applied for the other spin-1 particles.

    hep-phChin.Phys.Lett.(2025)·5 citations
11. 11*

    Scalar, Vector and Tensor Form Factors of Pion and Kaon

    Satyajit Puhan🇮🇳 · Harleen Dahiya🇮🇳

    We calculate the possible scalar, vector, and tensor form factors (FFs) for pion and kaon in the light-cone quark model (LCQM). These FFs are calculated from the leading and sub-leading twist generalized parton distribution functions (GPDs) of the pion and kaon. The vector and tensor FFs correspond to twist-2 GPDs, whereas the scalar FFs correspond to twist-3 scalar GPDs. We calculate the FFs from the GPDs quark-quark correlator and express them in the form of light-front wave functions (LFWFs). The behavior of these FFs was found to be in sync with experimental data, other model predictions, and lattice simulation results. We have also calculated the charge radii corresponding to different FFs and compared them with other models, lattice simulation results, and experimental data. The scalar radii of the pion and kaon of our model are found to be $0.528$ and $0.409$ $fm$, respectively.

    hep-phPRD(2025)·14 citations
12. 12*

    Radiative tail of the three-particle light-cone distribution amplitudes for the ${\Lambda }_b$ baryon in HQET

    Thorsten Feldmann🇩🇪 · Daniel Vladimirov🇩🇪

    We calculate the so-called radiative tail for the three-particle light-cone distribution amplitudes (LCDAs) of the ${\Lambda }_b$ baryon, following from the short-distance expansion of the defining light-ray operators in heavy-quark effective theory (HQET). To illustrate the effect of the radiative tail, we introduce a simple (model-dependent) extrapolation to large distances (respectively small momenta), which preserves the analytic properties of the LCDAs in HQET. We observe a similar qualitative behaviour as has been discussed for the $B$-meson case.

    hep-phJHEP(2025)·6 citations
13. 13*

    Role of the short-range dynamics in simultaneous interpretation of $P_{cs}$ pentaqurks via ${\Xi }_c^{(\prime ,\ast )}{\bar{D}}^{(\ast )}$ molecules

    Ziye Wang🇨🇳 · Nijiati Yalikun🇨🇳 · Yakefu Reyimuaji🇨🇳

    We investigate hidden-charm molecular states in ${\Xi }_c^{(\prime ,\ast )}{\bar{D}}^{(\ast )}$ systems using the one-boson exchange model. By regulating the short-range interactions with parameter $a$ and cutoff $\Lambda$, we found ten bound states in isoscalar systems. Our analysis reveals that if the LHCb Collaboration's $P_{cs}(4459)$ and Belle Collaboration's $P_{cs}(4472)$ pentaqurks are indeed distinct states, their mass splitting can be resolved through ${\Xi }_c^{\prime }\bar{D}$-${\Xi }_c{\bar{D}}^{\ast }$ coupled channel dynamics using consistent model parameters. This framework assigns $3/2^{-}$ and $1/2^{-}$ spin-parity quantum numbers to $P_{cs}(4459)$ and $P_{cs}(4472)$, respectively. With this consistent model parameter, we predict several new molecular candidates in the $4.3-4.7$ GeV mass region, demonstrating the crucial interplay between coupled channel effects and short-range dynamics in understanding hidden-charm pentaquarks as hadronic molecules. Additionally, we investigate the effects of $\Lambda {\eta }_c$ and $\Lambda J/\psi$ decay channels on the predicted molecular states, showing how these channels influence pole positions and provide insights into the detectability of these states through different production mechanisms.

    hep-phhep-thPRC(2025)·1 citation
14. 14*

    Neutrino magnetic moments: effective versus fundamental parameters

    Christoph A. Ternes🇮🇹 · Mariam Tórtola🇪🇸

    The search for neutrino magnetic moments offers a valuable window into physics beyond the Standard Model. However, a common misconception arises in the interpretation of experimental results: the assumption that the so-called effective neutrino magnetic moment is a universal, experiment-independent quantity. In reality, this effective parameter depends on the specific characteristics of each experiment, including the neutrino source, flavor composition or energy spectrum. As a result, the effective magnetic moment derived from solar neutrino data differs fundamentally from that obtained in reactor or accelerator-based experiments. Treating these quantities as directly comparable can lead to misleading conclusions. In this work, we clarify the proper definition of the effective neutrino magnetic moment in various experimental contexts and discuss the implications of this misconception for global analyses and theoretical interpretations.

    hep-phhep-exNPB(2025)·6 citations
15. 15*

    Local equilibrium Wigner function for spin-1/2 particles

    Samapan Bhadury🇵🇱 · Zbigniew Drogosz🇵🇱 · Wojciech Florkowski🇵🇱 · Sudip Kumar Kar🇵🇱 · Valeriya Mykhaylova🇵🇱

    Formal connections between the spin density matrix and the Wigner function for spin-1/2 particles forming a relativistic gas are explored to determine their general structures. They suggest that the commonly used form of the local equilibrium Wigner function should be replaced by a new expression. The latter fulfills the necessary condition for the normalization of the mean spin polarization, which the former fails to reproduce. The new definition of the Wigner function leads to generalized thermodynamic relations for perfect spin hydrodynamics, identical to those obtained earlier using the classical concept of spin. Moreover, one can prove that the perfect spin hydrodynamics based on the new equilibrium Wigner function is nonlinearly causal and stable. Finally, the selection rule for the Lagrange multipliers, which is satisfied by real systems, is discussed.

    hep-phnucl-th13 citations
16. 16*

    Production of leptonium in heavy quarkonium decays

    Yuhan Zhao🇨🇳 · Jun Jiang🇨🇳

    Lepton pairs with opposite charges can form bound states known as ``leptonium'' through quantum electrodynamic interactions. Heavy quarkonia such as $J/\psi$ are abundantly produced at facilities like BESIII and the future Super Tau-Charm Facility (STCF). In this work, we investigate leptonium production in heavy quarkonium decays, specifically focusing on the processes $\mathcal{Q}⟶(l_1^{+}{l}_2^{-})[n]+\gamma$ ($l_{1,2}=\tau ,\mu ,e$) and $\mathcal{Q}⟶(l_1^{+}{l}_2^{-})[n]+l_1^{-}{l}_2^{+}$. Here, $\mathcal{Q}$ denotes the heavy quarkonium $J/\psi$ or ${\rm Y}$, while $n=$ ${}^1{S}_0$ or ${}^3{S}_1$ corresponds to para-leptonium and ortho-leptonium, respectively. With an annual production of $3.4\times 10^{12}$ $J/\psi$ events at STCF, there is significant potential to observe positronium $(e^{+}{e}^{-})$, muonium $({\mu }^{+}{e}^{-})$, and dimuonium $({\mu }^{+}{\mu }^{-})$. In particular, the ortho-dimuonium $({\mu }^{+}{\mu }^{-}){[}^3{S}_1]$ may be discovered at the future STCF, with an inclusive branching fraction of $Br(J/\psi ⟶({\mu }^{+}{\mu }^{-}){[}^3{S}_1]+X)=1.5\times 10^{-12}$.

    hep-phPRD(2025)·3 citations
17. 17*

    Pomeron Evolution and Squeezed States in Quantum Optics

    Dima Cheskis🇮🇱 · Alex Prygarin🇮🇱

    We apply the formalism of coherent states in quantum optics to pomeron evolution and show that evolving squeezed pomeron states are equivalent to pomeron fan diagrams at the leading order of perturbative expansion. Based on our results, we interpret the action of the displacement operator as pomeron propagation and the action of the squeeze operator as pomeron interaction.

    hep-phhep-thNPB(2025)·1 citation
18. 18*

    Transverse single-spin asymmetries in $\gamma$SIDIS as a direct probe of quark-gluon-quark longitudinal momentum structure

    Michael Harris🇺🇸 · Jacob Marsh🇺🇸 · Daniel Pitonyak🇺🇸 · Alexei Prokudin🇺🇸 · Jack Putnam🇺🇸 · Daniel Rein🇩🇪 · Marc Schlegel🇩🇪

    Transverse single-spin asymmetries in the semi-inclusive deep-inelastic production of isolated photons ($\gamma$SIDIS), $A_{UT}^{\gamma \mathrm{SIDIS}}$, provide an unprecedented opportunity to extract the quark-gluon-quark correlators $F_{FT}(x,x^{\prime })$ and $G_{FT}(x,x^{\prime })$ point-by-point in their full support $x,x^{\prime }$. We utilize realistic models for these functions, based on input from the Sivers transverse momentum dependent parton distribution function and imposing constraints from the $d_2$ matrix element calculated in lattice QCD, in order to provide numerical estimates for $A_{UT}^{\gamma \mathrm{SIDIS}}$ at the Electron-Ion Collider (EIC). We thoroughly explore the EIC phase space in order to isolate in which regions the asymmetry can be sizable, finding it can be as much as $10\%$ or larger for certain kinematics. Given that $F_{FT}(x,x^{\prime })$ and $G_{FT}(x,x^{\prime })$ are basically unknown, $A_{UT}^{\gamma \mathrm{SIDIS}}$ will be an important future measurement to learn about multi-parton correlations in the nucleon.

    hep-phhep-exPLB(2025)·2 citations
19. 19*

    Emergence of the exotic bottomoniumlike state $Y(10650)$ and support from Belle and Belle II data

    Jun-Zhang Wang🇨🇳 · Yu-Bo Li🇨🇳 · Jian-Bo Cheng🇨🇳 · Zi-Yang Lin🇨🇳 · Lu Meng🇩🇪 · Cheng-Ping Shen🇨🇳 · Shi-Lin Zhu🇨🇳

    Near-threshold exotic hadrons are usually associated with $S$-wave hadron-hadron dynamics, while higher partial waves are expected to be strongly suppressed by the centrifugal barrier. We show that this expectation can be overturned in the bottomonium sector. In a coupled-channel meson exchange framework combined with the complex scaling method, we find a $J^{PC}=1^{--}$ pole, denoted as $Y(10650)$, generated dominantly by the $P$-wave $B^{\ast }{\bar{B}}^{\ast }$ interaction and located close to the $B^{\ast }{\bar{B}}^{\ast }$ threshold. This pole naturally accounts for the anomalous enhancement observed just above the opening of the $B^{\ast }{\bar{B}}^{\ast }$ threshold in $e^{+}{e}^{-}\to B^{\ast }{\bar{B}}^{\ast }$. Once its production strength is fixed by this threshold enhancement, the corresponding cross sections of $\sigma [e^{+}{e}^{-}\to Y(10650)\to B{\bar{B}}^{\ast }]$ are predicted by the pole residues and phase-space factors, giving a characteristic dip-or-peak structure consistent with the available Belle (II) data. We further study the hidden-bottom transition $Y(10650)\to {\rm Y}(2S)\eta$ through a near-threshold $B^{\ast }{\bar{B}}^{\ast }$ loop mechanism. The resulting $\mathcal{O}(10\sim 100\mathrm{keV})$ width for $Y(10650)\to {\rm Y}(2S)\eta$ is sufficient to account for the corresponding cross sections measured by Belle II. The simultaneous appearance of this state in open- and hidden-bottom channels provides a direct experimental path to test a $P$-wave near-threshold mechanism and makes $Y(10650)$ a strong candidate for the first neutral isoscalar exotic bottomoniumlike state in the spectral gap between ${\rm Y}(4S)$ and ${\rm Y}(5S)$.

    hep-phhep-ex4 citations
20. 20*

    Stabilizing dark matter with quantum scale symmetry

    Abhishek Chikkaballi🇵🇱 · Kamila Kowalska🇵🇱 · Rafael R. Lino dos Santos🇵🇱 · Enrico Maria Sessolo🇵🇱

    In the context of gauge-Yukawa theories with trans-Planckian asymptotic safety, quantum scale symmetry can prevent the appearance in the Lagrangian of couplings that would otherwise be allowed by the gauge symmetry. Such couplings correspond to irrelevant Gaussian fixed points of the renormalization group flow. Their absence in the theory implies that different sectors of the gauge-Yukawa theory are secluded from one another, in similar fashion to the effects of a global or a discrete symmetry. As an example, we impose the trans-Planckian scale symmetry on a model of Grand Unification based on the gauge group SU(6), showing that it leads to the emergence of several fermionic WIMP dark matter candidates whose coupling strengths are entirely predicted by the UV completion.

    hep-phPRD(2025)·7 citations
21. 21*

    Exploring two component doublet dark matter

    Mariana Frank🇨🇦 · Purusottam Ghosh🇮🇳 · Chayan Majumdar🇬🇧 · Supriya Senapati🇺🇸

    We propose a two-component dark matter (DM) scenario by extending the Standard Model with two additional $SU(2{)}_L$ doublets, one scalar, and another fermion. To ensure the stability of the DM components, we impose a global $Z_2\times Z_2^{\prime }$ symmetry. The lightest neutral states for both the scalar and fermion, which are non-trivially transformed under the extended symmetry, behave as stable two-component DM candidates. While single components are under-abundant due to their gauge interactions, in a mass region between $m_W$ and $525$ GeV for the scalar and a mass below $1200$ GeV for the fermion, and the fermion DM conflicts with direct detection limits over the whole parameter space, having two components helps to saturate relic density in the regions with under-abundance. Compliance with direct detection constraints leads to two options, either introducing dim-5 effective operators, or embedding the scenarios into a complete UV theory, which reproduces a type II seesaw model, thus naturally including neutrino masses. We analyze the consequences of this scenario at the LHC.

    hep-phPRD(2025)·5 citations
22. 22*

    Probing Boson Clouds with Supermassive Black Hole Binaries

    Ximeng Li🇨🇳 · Jing Ren🇨🇳 · Xi-Li Zhang🇨🇳

    Rotating black holes can generate boson clouds via superradiance when the boson's Compton wavelength is comparable to the black hole's size. In binary systems, these clouds can produce distinctive observational imprints. Recent studies accounting for nonlinearities induced by orbital backreaction suggest that if the binary forms at a large separation, resonance transitions can significantly deplete the cloud, minimizing later observational consequences except for very specific orbital inclinations. In this paper, we extend this framework to supermassive black hole binaries (SMBHBs), considering the influence of their astrophysical evolutionary histories. We find that, before entering the gravitational wave (GW) radiation stage, the additional energy loss channels can accelerate orbital evolution. This acceleration makes hyperfine resonant transitions inefficient, allowing a sufficient portion of the cloud to remain for later direct observations. We further discuss the ionization effects and cloud depletion occurring at this stage. Based on these theoretical insights, we explore how multi-messenger observations for SMBHBs can be utilized to detect the ionization effects of boson clouds by examining changes in the orbital period decay rate via electromagnetic measurements and variations in GW strain over a wide frequency band. Our findings reveal a complex dependence on the binary's total mass, mass ratio, and boson mass, emphasizing the significant role of astrophysical evolution histories in detecting boson clouds within binaries.

    hep-phastro-ph.HEJCAP(2026)·8 citations
23. 23*

    Local vs. nonlocal entanglement in top-quark pairs at the LHC

    M. Fabbrichesi🇮🇹 · R. Floreanini🇮🇹 · L. Marzola🇪🇪

    We show that the entanglement observed in top-antitop quark spin states at the LHC is local in the energy region close to the production threshold. In contrast, nonlocal entanglement is observed in the central boosted region defined by a top-quark pair invariant mass $m_{t\bar{t}}>800$ GeV and scattering angles $\Theta$ satisfying $|\cos \Theta |<0.2$. This makes top-quark pairs a unique laboratory for studying the interplay between entanglement and Bell locality. The locality of entanglement near the production threshold is further supported by a recent CMS analysis, which reports a significance of more than $5\sigma$. We also demonstrate that there exists a kinematic region where the spin states of the top-antitop quark are separable, yet they exhibit non-zero discord and magic.

    hep-phhep-exJHEP(2025)·20 citations
24. 24*

    Positivity in the Renormalization of Effective Field Theory

    You-Peng Liao🇹🇼 · Jasper Roosmale Nepveu🇹🇼 · Chia-Hsien Shen🇹🇼

    We show that the direction of renormalization in effective field theory is constrained by fundamental principles in the infrared$—$unitarity, analyticity, and Lorentz invariance. Our theorem, in the spirit of the $a$-theorem in conformal field theory, determines the sign of the one-loop running of couplings in the forward limit, when one inserts two operators whose mass dimensions are identical and even. The theorem holds for a broad class of effective field theories with arbitrary ultraviolet completions. The constraint directly applies to linear positivity bounds derived using tree-level amplitudes in the infrared, providing a criterion for whether renormalization effects can preserve the positivity bounds, or lead to their apparent violation. We discuss the phenomenological implications of our theorem in chiral perturbation theory and the Standard Model Effective Field Theory, where our theorem is particularly constraining for the running at dimension eight. We provide several examples and show various extensions and applications even at dimension six.

    hep-phhep-thPRD(2026)·14 citations
25. 25*

    ACT DR6 Insights on the Inflationary Attractor models and Reheating

    Md Riajul Haque🇮🇳 · Sourav Pal🇮🇳 · Debarun Paul🇮🇳

    We investigate the observational constraints on $\alpha$-attractor inflationary models and their post-inflationary reheating dynamics in light of the latest CMB data from ACT DR6 combined with Planck18, BICEP/$Keck$ 2018, and DESI (P-ACT-LB-BK18). Focusing on both E- and T-type attractor potentials, we analyze how inflationary observables, namely the scalar spectral index $n_s$ and the tensor-to-scalar ratio $r$, are indirectly influenced by reheating parameters such as the reheating temperature $T_{\text{RH}}$, the inflaton EoS $w_{\varphi }$, and consequently the inflaton's couplings to SM particles. We incorporate constraints from PGW overproduction via $\Delta N_{\mathrm{eff}}$ bounds. Additionally, we include theoretical constraints from CW one-loop radiative corrections, as well as inflaton self-resonance, a non-perturbative effect that can occur even in the absence of inflaton-SM interactions and imposes a strong lower limit, particularly significant for $1/3\lesssim w_{\varphi }\lesssim 0.7$. Our analysis shows that E-models allow a broad range of reheating scenarios, including matter-like reheating ($w_{\varphi }=0$), whereas the T-model yields more restrictive results and remains viable only for $w_{\varphi }>1/2$ for all three non-gravitational interaction channels, $\varphi \to \bar{f}f$, $\varphi \to bb$, and $\varphi \varphi \to bb$ are considered. For stiffer EoS, an intermediate coupling window survives, bounded from above by CW corrections or $2\sigma$ observational limits, and from below by the combined PGW and self-resonance constraints. We derive updated bounds on inflaton couplings for both decay and scattering channels and identify parameter regions consistent with successful perturbative reheating. These results establish a robust connection between inflationary dynamics, reheating physics, and particle interactions, and provide concrete targets for upcoming precision CMB observations.

    ↳ astro-ph.COhep-phhep-thPRD(2026)·59 citations
26. 26*

    Revisiting Quantization of Gauge Field Theories: Sandwich Quantization Scheme

    M.M. Sheikh-Jabbari🇮🇷

    Quantization of field theories with gauge symmetry is an extensively discussed and well-established topic. In this short note, we revisit this old problem. While we confirm all details of the existing literature, we highlight a potentially important point which may provide a better understanding of and insights on the quantization of gauged systems. The gauge degrees of freedom have vanishing momenta, and hence their equations of motion appear as constraints on the system. We argue that to ensure consistency of quantization one can impose these constraints as ``sandwich conditions'': The physical Hilbert space of the theory consists of all states for which the constraints sandwiched between any two physical states vanish. We solve the sandwich constraints and show they have solutions not discussed in the gauge field theory literature. We briefly discuss the physical meaning of these solutions and the implications of the "sandwich quantization scheme".

    ↳ hep-thhep-phmath-phmath.MPNPB(2026)·3 citations
27. 27*

    On the momentum of gluons in Lattice Gauge Theory (LGT)

    Herbert Neuberger🇺🇸

    Attempts to improve LGT simulation algorithms by Fourier space preconditioning have been handicapped by the gauge dependence of momenta, familiar from perturbation theory. The continuum theory has a gauge invariant energy-momentum density, indicating this to be a fake obstacle. While perturbation-theory momenta are evidently wrong for the task, momentum-transfer carried by gluons is physical. Simulations using these momenta may become practical in the near future thanks to recent progress in generative models, stochastic and/or deterministic.

    ↳ hep-lathep-phhep-thInt.J.Mod.Phys.A(2025)·0 citations
28. 28*

    Realization of all-to-all fermion propagator for the first principle high accuracy strong interaction prediction

    Zhi-Cheng Hu🇨🇳 · Ji-Hao Wang🇨🇳 · Xiangyu Jiang🇨🇳 · Liuming Liu🇨🇳 · Shi-Hao Su🇨🇳 · Peng Sun🇨🇳 · Yi-Bo Yang🇨🇳

    We propose a ``blending" algorithm that projects the all-to-all fermion propagator onto spatial low-frequency modes (LFM) combined with a stochastic estimate of spatial high-frequency modes (SHFM) at each time slice. This approach enables the calculation of arbitrary-point correlation functions for arbitrary hadron states in strongly interacting quantum field theories (QFT) with fermions, such as quantum chromodynamics (QCD). Specifically, LFM allows the construction of spatially extended hadron states below a certain energy threshold by diagonalizing multi-fermion interpolation fields. Meanwhile, the local interactions required for N-point correlation functions in QFT can be approximated in an unbiased manner through a reweighted summation of both LFM and SHFM contributions. To demonstrate the efficiency of this algorithm, we obtained {\color{black} $g_A^u=0.895(15)$, $g_A^d=-0.338(15)$, $g_A^s=-0.0245(72)$, $g_A^{u+d+s}=0.533(28)$ and $g_A^{u-d}=1.2339(43)$ } for nucleon at $m_{\pi }=300$ MeV and $a=0.077$ fm using 40 configurations. The consistency check of the pion electric form factor and charge radius derived from 3-point and 4-point correlation functions is also provided.

    ↳ hep-lathep-phnucl-th3 citations
29. 29*

    Generalized susceptibilities and the properties of charm degrees of freedom across the QCD crossover temperature

    Olaf Kaczmarek🇩🇪 · Frithjof Karsch🇩🇪 · Peter Petreczky🇺🇸 · Christian Schmidt🇩🇪 · Sipaz Sharma🇩🇪

    We study the generalized charm susceptibilities in 2+1 flavor QCD on the lattice at several lattice spacings. We show that, below the chiral crossover, these susceptibilities are well described by the hadron resonance gas (HRG) model if charmed hadrons not listed in tables of the Particle Data Group are included. However, the HRG description abruptly breaks down just above the chiral crossover. To understand this, we use a model for the charm pressure in which it is expressed as the sum of partial pressures from charmed baryons, charmed mesons, and charm quarks. We present continuum estimates of these partial pressures and find that, while the partial pressures of charmed mesons and baryons drop below their respective HRG predictions, the charm quark pressure becomes non-zero above the chiral crossover.

    ↳ hep-lathep-exhep-phhep-thPRD(2025)·9 citations
30. 30*

    Chiral anomaly from (anomalous) spin hydrodynamics

    Jay Armas🇳🇱 · Giorgos Batzios🇳🇱

    We show that the low energy fluctuations of spinning black Dp branes are described by a theory of spin hydrodynamics on a spacetime ${\mathbb{M}}_{p+1}\times {\mathbb{T}}^{n+2}$ in which the fluid is flowing on ${\mathbb{M}}_{p+1}$ and spinning on ${\mathbb{T}}^{n+2}$. Focusing on the hydrodynamic regime of $\mathcal{N}=4$ supersymmetric Yang-Mills theory, we provide a geometric interpretation of the R-current anomaly in terms of a gravitational anomaly from the ten-dimensional point of view. This follows from the holographic duality between a spinning fluid in ten dimensions and an anomalous chiral fluid in four dimensions. We comment on the relations between the theory of spin hydrodynamics introduced here and other theories of spin hydrodynamics in the context of heavy-ion collisions.

    ↳ hep-thhep-phnucl-thPRD(2026)·3 citations
31. 31*

    Dirac Singleton as a Relativistic Field Beyond Standard Model

    M.A. Vasiliev🇷🇺

    A new interpretation of Dirac singletons \cite{Dirac:1963ta}, i.e. free conformal fields in $d$ dimensions, as relativistic fields in a $d+1$-dimensional space-time with cosmological constant, that differs from the Flato-Fronsdal dipole construction in $Ad{S}_{d+1}$ \cite{Flato:1986uh}, is proposed. The $d+1$-dimensional field is described at the level of both equations and Lagrangian. It forms an infinite-dimensional representation of the $d+1$-dimensional Lorentz group that relates fields at different space-time points. The associated well-known fact is that singleton cannot be localized at a point in $d+1$ dimensions, hence being unobservable via local scattering/radiation phenomena in the Standard Model ($d=3$). On the other hand, that singleton respects $d+1$ dimensional relativistic symmetries makes it possible to introduce its interactions with gravity and other relativistic fields in $d+1$ dimensions. It is speculated that the presence of singleton in a four-dimensional field theory with non-zero cosmological constant (dark energy) can be relevant to the dark matter phenomenon and baryon asymmetry generation.

    ↳ hep-thastro-ph.HEgr-qchep-ph1 citation
32. 32*

    Gauge invariance and color charge fluctuations

    Thomas D. Cohen🇺🇸

    The nature of confinement is connected with color charge. Unfortunately, the color charge densities in QCD, the Noether charge densities associated with the global color invariance, are not invariant under local color rotations. This implies that the expectation values of the net color charge in any region of any physical state in QCD, states that satisfy the color Gauss law, are automatically zero for all components of color. In this paper it is shown that the expectation value of the square of the net color charge in a region, a measure of the color charge fluctuations, is necessarily nonzero when evaluated in physical states and the result, while depending on the scheme and scale by which the theory is regulated, is gauge invariant. This holds despite the formal lack of gauge invariance of the operator. Moreover, there is a particular combination of the color charge fluctuations for the vacuum and for a system describable by a non-trivial density matrix that is independent that has a well-defined continuum limit

    ↳ hep-lathep-phhep-thnucl-thPRC(2025)·0 citations
33. 33*

    Bogomol'nyi Equations and Coexistence of Vortices and Antivortices in Generalized Abelian Higgs Theories

    Aonan Xu🇨🇳 · Yisong Yang🇺🇸

    We derive the Bogomol'nyi equations in generalized Abelian Higgs theories which allow the coexistence of vortices and antivortices over a compact Riemann surface or the full plane. In the compact surface situation, we obtain a necessary and sufficient condition for the existence of a unique solution describing a system of coexisting vortices and antivortices. In the full-plane situation, we prove the existence of a unique solution representing an arbitrary distribution of vortices and antivortices and obtain sharp asymptotic behavior of the solution near infinity. These solutions carry quantized magnetic fluxes and energies explicitly expressed in terms of the numbers of vortices and antivortices topologically characterized by the first Chern and Thom classes.

    ↳ math-phhep-phhep-thmath.MPProc.Roy.Soc.Lond.A(2025)·3 citations
34. 34*

    Stochastic analysis of finite-temperature effects on cosmological parameters by artificial neural networks

    Armin Hatefi🇨🇦 · Ehsan Hatefi🇪🇸 · I. Y. Park🇺🇸

    We explore the impact of finite-temperature quantum gravity effects on cosmological parameters, particularly the cosmological constant $\Lambda$, by incorporating temperature-dependent quantum corrections into the Hubble parameter. For that purpose, we modify the Cosmic Linear Anisotropy Solving System. We introduce new density parameters, ${\Omega }_{{\Lambda }_2}$ and ${\Omega }_{{\Lambda }_3}$, arising from finite-temperature quantum gravity contributions, and analyze their influence on the cosmic microwave background power spectrum using advanced machine learning techniques, including artificial neural networks and stochastic optimization. Our results reveal that ${\Omega }_{{\Lambda }_2}$ assumes a negative value, consistent with dimensional regularization in renormalization and that the presence of ${\Omega }_{{\Lambda }_2}$ as well as ${\Omega }_{{\Lambda }_3}$ enhances model accuracy. Numerical analyses demonstrate that the inclusion of these parameters improves the fit to 2018 Planck data. Although further work is required, our results suggest that finite-temperature quantum gravity effects may play a non-negligible role in cosmological evolution. Although the Hubble tension persists, our findings highlight the potential of quantum gravitational corrections in refining cosmological models and motivate further investigation into higher-order thermal effects and polarization data constraints.

    ↳ astro-ph.COgr-qchep-phhep-th3 citations
35. 35*

    Jet shape modification in a transport calculation

    Monideepa Maity🇮🇳 · Subrata Pal🇮🇳

    A precise quantification of the medium-modification of the high transverse momenta jets in relativistic heavy ion collisions rely on consistent modelling of elastic and inelastic energy loss suffered by the jet and the concurrent underlying medium evolution. We have developed a unified framework for jet and bulk medium evolution within a multiphase transport approach where the jets and medium share energy and momentum via multiple elastic scatterings and medium-induced gluon radiation during the parton transport. The formulation enables realistic predictions of jet based observables extended to a large radius of the jet cone in central Pb-Pb collisions at 5.02 TeV. The model provides reasonable quantitative agreement with the experimental data from inclusive jet suppression and the full jet shape function up to large radial distances induced by both the collisional and radiative jet energy loss and migration of the lost $p_T$ in the medium. We find that gradual degradation of jet energy through gluon emissions alters the energy-momentum evolution in the jet, essential to describe the entire range of jet shape ratio relative to proton-proton collisions. Pure collisional energy loss injects appreciable $p_T$ broadening and migration of the medium partons, resulting in an enhanced population at large angular distances in the jet-shape ratio.

    ↳ nucl-thhep-phPLB(2025)·0 citations
36. 36*

    Constraining the neutron star equation of state by including the isoscalar-vector and isovector-vector coupling using the Bayesian analysis

    Deepak Kumar🇮🇳 · Pradip Kumar Sahu🇮🇳

    We constrain the nuclear matter equation of state within the relativistic mean field model by including the isoscalar-vector and isovector-vector coupling term at a fundamental level using the Bayesian analysis. We used the nuclear saturation properties and recent astrophysical observations to constrain the dense matter equation of state. We obtained about 20000 sets of equations of states out of sampling about 60 millions sets of equations of states. All 20000 equations of states satisfy nuclear matter saturation properties at saturation densities and produces high mass neutron stars. In our findings, we find that the non-zero value of isoscalar-vector and isovector-vector coupling parameter and negative value of sigma meson self-coupling stiffen the equation of state. Our sets of equations of state produces neutron stars of mass larger than 2.5 M${}_{\odot }$ to include the recent gravitational waves observation GW190419.

    ↳ nucl-thastro-ph.HEhep-phhep-th2 citations
37. 37*

    Evolving Dark Energy or Evolving Dark Matter?

    Xingang Chen🇺🇸 · Abraham Loeb🇺🇸

    We show that the latest empirical constraints on cosmology, from a combination of DESI, CMB and supernova data, can be accounted for if a small component of dark matter has an evolving and oscillating equation of state within $-1<w<1$. From a fundamental physics perspective, this interpretation is more appealing than an evolving phantom dark energy with $w<-1$, which violates the null energy condition.

    ↳ astro-ph.COhep-phhep-thJCAP(2025)·48 citations
38. 38*

    Probing the dimuon channel of a Z' boson at the HL-LHC using multivariate analysis

    Ali Muhammad H. H.🇪🇬 · El-sayed A. El-dahshan🇪🇬 · S. Elgammal🇪🇬

    The upcoming upgrade of the existing LHC facility at CERN is known as the High-Luminosity Large Hadron Collider (HL-LHC). It is designed to extend its physics reach by substantially increasing the integrated luminosity. It will enable more precise measurements of the Standard Model (SM) and improve sensitivity to rare events and possible new physics signatures. This study adopts a multivariate analysis (MVA) approach to effectively discriminate the dark Higgs (DH) signal against the dominant SM background. The analysis targets the leptonic decay mode of the $Z^{\prime }$ boson, focusing on the dimuon final state at $\sqrt{s}=14,\text{TeV}$ and $3000,{\text{fb}}^{-1}$ integrated luminosity corresponding to the HL-LHC. The DH signal is examined using the Toolkit for Multivariate Analysis (TMVA), employing and comparing the performance of three classifiers: Boosted Decision Trees (BDT), Deep Neural Networks (DNN), and Likelihood estimators.

    ↳ hep-exhep-phNPB(2025)·0 citations
39. 39*

    Dynamical coupled-channel models for hadron dynamics

    Michael Döring🇺🇸 · Johann Haidenbauer🇩🇪 · Maxim Mai🇺🇸 · Toru Sato🇯🇵

    Dynamical coupled-channel (DCC) approaches parametrize the interactions and dynamics of two and more hadrons and their response to different electroweak probes. The inclusion of unitarity, three-body channels, and other properties from scattering theory allows for a reliable extraction of resonance spectra and their properties from data. We review the formalism and application of the ANL-Osaka, the Juelich-Bonn-Washington, and other DCC approaches in the context of light baryon resonances from meson, (virtual) photon, and neutrino-induced reactions, as well as production reactions, strange baryons, light mesons, heavy meson systems, exotics, and baryon-baryon interactions. Finally, we also provide a connection of the formalism to study finite-volume spectra obtained in Lattice QCD, and review applications involving modern statistical and machine learning tools.

    ↳ nucl-thhep-lathep-phnucl-exPPNP(2026)·45 citations
40. 40*

    High-Frequency Gravitational Wave Search with ABRACADABRA-10\,cm

    Kaliroë M. W. Pappas🇺🇸 · Jessica T. Fry🇺🇸 · Sabrina Cheng🇺🇸 · Arianna Colón Cesaní🇺🇸 · Jonathan L. Ouellet🇺🇸 · Inoela Vital🇺🇸 · Lindley Winslow🇺🇸 · Valerie Domcke🇨🇭 · Sung Mook Lee🇨🇭 · Joshua W. Foster🇺🇸 · Reyco Henning🇺🇸 · Yonatan Kahn🇨🇦 and 3 other authors

    High-frequency gravitational waves (HFGWs), above 10 kHz, promise a clean probe of new physics, largely free of the astrophysical backgrounds that complicate lower-frequency searches. Axion detectors, which search for axion dark matter via its coupling to electrodynamics in a strong magnetic field, should also be sensitive to HFGWs. We present the first dedicated search for HFGWs, using a modified ABRA-10cm axion detector, ABRA-GW, that runs simultaneously with a conventional axion search. ABRA-GW opens the 10 kHz-5 MHz band to HFGW searches and performs the first transient search by an axion experiment, targeting primordial black hole (PBH) mergers. Axion sensitivity is unaffected by the added gravitational-wave channel, and HFGW sensitivity matches theoretical expectations. This work demonstrates the broad physics reach of axion detectors and represents a first step toward a potential HFGW discovery.

    ↳ hep-exastro-ph.COgr-qchep-ph20 citations
41. 41*

    Vlasov Perturbation Theory applied to $\Lambda$CDM

    Mathias Garny🇩🇪 · Dominik Laxhuber🇩🇪 · Roman Scoccimarro🇺🇸

    We apply the framework of Vlasov Perturbation Theory (VPT) to the two-loop matter power spectrum within $\Lambda$CDM cosmologies. The main difference to Standard Perturbation Theory (SPT) arises from taking the velocity dispersion tensor into account, and the resulting screening of the backreaction of UV modes renders loop integrals cutoff-independent. VPT is informed about non-perturbative small scale dynamics via the average value of the dispersion generated by shell-crossing, which impacts the evolution of perturbations on weakly non-linear scales. When using an average dispersion from halo models, the VPT power spectrum agrees with the one from the simulation, up to differences from missing three-loop contributions. Alternatively, treating the average dispersion as free parameter we find a remarkably stable prediction of the matter power spectrum from collisionless dynamics at percent level for a wide range of the dispersion scale. We quantify the impact of truncating the Vlasov hierarchy for the cumulants of the phase-space distribution function, finding that the two-loop matter power spectrum is robust to neglecting third and higher cumulants. Finally, we introduce and validate a simplified fast scheme fVPT that can be easily incorporated into existing codes and is as numerically efficient as SPT.

    ↳ astro-ph.COhep-phPRD(2025)·8 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.