Fri·Apr 18, 2025Friday·April 18, 2025

1. 01*

   Enhancing Sensitivity for Di-Higgs Boson Searches Using Anomaly Detection and Supervised Machine Learning Techniques

   Sergei V. Chekanov🇺🇸 · Wasikul Islam🇺🇸 · Nicholas Luongo🇺🇸

   This paper explores different strategies for enhancing sensitivity to new heavy resonances that decay into two or more Higgs bosons. This is achieved using two neural network architectures: an unsupervised autoencoder for anomaly detection and a supervised classifier. The autoencoder is trained on a small fraction of Standard Model (SM) Monte Carlo simulated events to calculate the loss distribution for input events, aiding in determining the extent to which events can be considered anomalous. The supervised classifier uses the same inputs but is trained on events simulated using both beyond Standard Model (BSM) and SM processes. By applying selection cuts to the output scores, we compare the sensitivities of the two approaches.

   hep-ph3 citations
2. 02*

   Searching for the LFV $\gamma \gamma e\mu$ interaction at future $e^{-}{e}^{+}$ colliders

   M. A. Arroyo-Ureña🇲🇽 · R. Gaitán🇲🇽 · Marcela Marín🇲🇽 · Humberto Salazar🇲🇽 · M. G. Villanueva-Utrilla🇲🇽

   We investigate the Lepton Flavor Violating (LFV) process $e^{+}{e}^{-}\to e^{+}{e}^{-}e\mu$ ($e=e^{-},e^{+},\mu ={\mu }^{-},{\mu }^{+}$) at future circular colliders, probing the effective $\gamma \gamma e\mu$ interaction through photon fusion. Within an Effective Field Theory (EFT) framework compatible with theoretical and experimental constraints, we identify regions in the parameter space of the effective couplings where the signal could be observed at the Circular Electron-Positron Collider (CEPC) at $\sqrt{s}=240\text{GeV}$ and the Future Circular Collider (FCC-ee) at $\sqrt{s}=240$ and $350\text{GeV}$. Our analysis leverages distinctive kinematic distributions -- particularly the transverse momentum of the scattered electron $p_T^{(e^{-}\text{scattered})}$ and the central muon $p_T^{\mu }$ -- to achieve efficient signal-background separation. By employing a neural network classifier, we enhance the sensitivity beyond traditional cut-based methods, demonstrating the discovery potential of these facilities for LFV searches in the clean environment of $e^{+}{e}^{-}$ collisions.

   hep-phPRD(2026)·2 citations
3. 03*

   Holographic phase transitions via thermally-assisted tunneling

   Tony Gherghetta🇺🇸 · Arpon Paul🇺🇸 · Andrey Shkerin🇨🇦

   We construct the thermal bounce solution in holographic models that describes first-order phase transitions between the deconfined and confined phases in strongly-coupled gauge theories. This new, periodic Euclidean solution represents transitions that occur via thermally-assisted tunneling and interpolates between the $O(4)$-symmetric vacuum bubble at zero temperature and the high temperature $O(3)$-symmetric critical bubble associated with classical thermal fluctuations. The exact thermal bounce solution can be used to obtain the bounce action at low temperatures which allows for a more accurate determination of vacuum decay rates, significantly improving previous estimates in holographic models. In particular, provided the phase transition is sufficiently supercooled, new predictions are obtained for the gravitational wave signal strength for critical temperatures ranging from the TeV scale up to $10^{12}$ GeV, some of which are within reach of future gravitational wave detectors.

   hep-phgr-qchep-thJHEP(2025)·6 citations
4. 04*

   Slow Quanta Bound States and a Possible Link to Dark Matter

   Bruce Denby🇫🇷

   We study the possibility of elementary energy quanta with vacuum propagation speed w < c, capable of interacting with each other to form massive bound states. The slow matter thus formed is shown to follow laws of Special Relativity mediated by velocity w rather than c, and to possess dynamical properties recalling some characteristics of Dark Matter.

   hep-ph0 citations
5. 05*

   Toponium: Implementation of a toponium model in FeynRules

   Jing-Hang Fu🇨🇳 · Yu-Jie Zhang🇨🇳 · Guang-Zhi Xu🇨🇳 · Kui-Yong Liu🇨🇳

   Toponium -- a bound state of the top-antitop pair ($t\bar{t}$) -- emerges as the smallest and simplest hadronic system in QCD, with an ultrashort lifetime (${\tau }_t\sim 2.5\times 10^{-25}$~s) and a femtometer-scale Bohr radius ($r_{\text{Bohr}}\sim 7\times 10^{-18}$~m). We present a computational framework extending the Standard Model (SM) with two S-wave toponium states: a spin-singlet ${\eta }_t$ ($J^{PC}=0^{-+}$) and a spin-triplet $J_t$ ($J^{PC}=1^{--}$). Using nonrelativistic QCD (NRQCD) and a Coulomb potential, we derived couplings to SM particles (gluons, electroweak bosons, Higgs boson, and fermion pairs) and implemented the Lagrangian in FeynRules, generating FeynArts, MadGraph, and WHIZARD models for collider simulations. Key results include dominant decay channels (${\eta }_t\to gg/ZH$, $J_t\to W^{+}{W}^{-}/b\bar{b}$) and leading order (LO) cross sections for $pp\to {\eta }_t(nS)\to \mathrm{non}-t\bar{t}$ ({66 fb} at 13 TeV). The model avoids double-counting artifacts by excluding direct $t\bar{t}$ couplings, thereby ensuring consistency with perturbative QCD. This work establishes a complete pipeline for precision toponium studies, bridging NRQCD, collider phenomenology, and tests of SM validity at future lepton colliders (e.g., CEPC, FCC-ee, muon colliders) and the LHC. This provides the first publicly available UFO model for toponium, enabling direct integration with MadGraph and WHIZARD for simulations.

   hep-ph11 citations
6. 06*

   $D{\bar{D}}_1(2420)$ and $D^{\ast }{\bar{D}}^{\ast }(2400)$ molecular states: Probing their electromagnetic fingerprints

   U. Özdem🇹🇷

   As in previous decades, a comprehensive understanding of the intricate internal configuration of hadrons continues to be a central objective within both experimental and theoretical hadron physics. This pursuit plays a pivotal role in advancing our knowledge of QCD and critically evaluating the robustness and accuracy of the theoretical models developed to date. Furthermore, deciphering the underlying mechanisms of exotic states, both those currently observed and those anticipated in future experiments, remains a pressing and unresolved challenge. Motivated by this, in the present study, we investigate the electromagnetic properties of the $D{\bar{D}}_1(2420)$ and $D^{\ast }{\bar{D}}^{\ast }(2400)$ molecular tetraquark states with quantum numbers $J^{PC}=1^{--}$, using the QCD light-cone sum rule method. These states are analyzed within a hadronic molecular framework, where their magnetic and quadrupole moments are computed to probe internal structure and geometric deformation. Our results reveal distinct electromagnetic signatures, with the magnetic moments primarily dominated by light-quark contributions, and the quadrupole moments suggesting an oblate charge distribution. The findings are compared with prior studies assuming compact tetraquark configurations, emphasizing the sensitivity of electromagnetic observables to the underlying hadronic structure. This analysis provides critical insights into the nature of exotic hadrons and contributes to the broader understanding of QCD dynamics in the non-perturbative regime.

   hep-phhep-exhep-latPRD(2025)·2 citations
7. 07*

   First insight into transverse-momentum-dependent fragmentation physics at photon-photon colliders

   Simone Anedda🇮🇹 · Francesco Murgia🇮🇹 · Cristian Pisano🇮🇹

   Future planned lepton colliders, both in the circular and linear configurations, can effectively work as virtual and quasi-real photon-photon colliders and are expected to stimulate an intense physics program in the next few years. In this paper, we suggest to consider photon-photon scattering as a useful source of information on transverse momentum dependent fragmentation functions (TMD FFs), complementing semi-inclusive deep inelastic scattering and $e^{+}{e}^{-}$ annihilation processes, which provide most of the present phenomenological information on TMD FFs. As a first illustrative example, we study two-hadron azimuthal asymmetries around the jet thrust-axis in the process ${\ell }^{+}{\ell }^{-}\to {\gamma }^{\ast }\gamma \to q\bar{q}\to h_1{h}_2+X$, in which in a circular lepton collider one tagged, deeply-virtual photon scatters off an untagged quasi-real photon, both originating from the initial lepton beams, producing inclusively an almost back-to-back light-hadron pair with large transverse momentum, in the ${\gamma }^{\ast }\gamma$ center of mass frame. Similar processes, in a more complicated environment due to the presence of initial hadronic states, can also be studied in ultraperipheral collisions at the LHC and the planned future hadron colliders.

   hep-phPRD(2025)·2 citations
8. 08*

   Notes on optimizing a multi-sensor gradient axion-like particle dark matter search

   Daniel Gavilan-Martin🇩🇪 · Grzegorz Łukasiewicz🇵🇱 · Derek F. Jackson Kimball🇺🇸 · Szymon Pustelny🇵🇱 · Dmitry Budker🇩🇪 · Arne Wickenbrock🇩🇪

   Axion-like particles (ALPs) arise from well-motivated extensions to the Standard Model and could account for the dark matter. We discuss the scaling of the sensitivity of a galactic ALP dark matter search with the number of sensors, especially in the ultra-light mass regime, where the measurement time is shorter than the coherence time of the ALP field. We compare multiple schemes for daily modulated ALP gradient signals, and show that increasing the number of sensors from 1 to 2 improves the signal-to-noise ratio (SNR) by a factor of 2-3. For more than two sensors, the SNR increases as the square root of the number of sensors. Then, we show that splitting the data into subsets and then averaging its Discrete Fourier Transforms (DFTs) is equivalent to the DFT of the whole dataset in terms of SNR.

   hep-phPoS(2025)·1 citation
9. 09*

   Dipole-pion cross section in the saturation regime

   G.R.Boroun🇮🇷 · B.Z. Kopeliovich🇨🇱

   The scale-dependent dipole-pion cross section is analyzed as a function of the dipole size $r$ and the impact parameter $b$. This analysis relies on the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equation in $\mu \sim 1/r+{\mu }_0$ at the next-to-leading order (NLO) approximation, with a specific initial condition at ${\mu }_0$. The dipole-pion cross section at small Bjorken variable $\beta$ is being considered over a wide range of transverse separations $r$. Using the Laplace transformation technique, we describe the determination of the dipole-pion cross section based on the gluon distribution at the initial scale ${\mu }_0$ within a kinematic region characterized by low values of the Bjorken variable $\beta$. We found that geometric scaling for the dipole-pion cross section holds approximately within a wide kinematic region of $r{Q}_s$. The cross section saturates at large dipole sizes.

   hep-phPRD(2025)·1 citation
10. 10*

    Exact-WKB Analysis of Two-level Floquet Systems

    Toshiaki Fujimori🇯🇵 · Syo Kamata🇯🇵 · Tatsuhiro Misumi🇯🇵 · Naohisa Sueishi🇯🇵 · Hidetoshi Taya🇯🇵

    We explore the application of the exact Wentzel-Kramers-Brillouin (WKB) analysis to two-level Floquet systems and establish a systematic procedure to calculate the quasi-energy and Floquet effective Hamiltonian. We show that, in the exact-WKB analysis, the quasi-energy and Floquet effective Hamiltonian can be expressed in terms of cycle integrals (Voros symbol), which characterize monodromy matrices for Schrödinger-type differential equations governing two-level Floquet systems. We analytically evaluate the cycle integrals using the low-frequency expansion and derive both perturbative and non-perturbative corrections to the quasi-energy and Floquet effective Hamiltonian. To verify the accuracy of our results, we compare them with numerical calculations and analyze resonant oscillations, which reveal non-perturbative features that cannot be captured by the perturbative expansion.

    hep-phhep-thPTEP(2025)·5 citations
11. 11*

    Why $w\ne -1$? Anthropic Selection in a $\Lambda$ + Axion Dark Energy Model

    Kai Murai🇯🇵 · Fuminobu Takahashi🇯🇵

    We study a dark energy model composed of a bare negative cosmological constant and a single ultra-light axion, motivated by the string axiverse. Assuming that intelligent observers arise and observe, as in our universe, the onset of dark-energy-driven acceleration following matter domination, and that this acceleration persists to the present, we derive nontrivial constraints on both the axion mass and the bare cosmological constant. The axion mass is bounded from above to avoid fine-tuning of the initial misalignment angle near the hilltop, and from below because too light axions cannot achieve accelerated expansion due to their limited energy budget. As a result, the anthropically allowed axion mass range typically lies around $m=\mathcal{O}(10)H_0$ for a decay constant close to the Planck scale, where $H_0$ is the observed value of the Hubble constant. In this framework, the dark energy equation-of-state parameter $w_0$ generically deviates from $-1$ by $\mathcal{O}(0.1)$, providing a natural explanation for why $w\ne -1$ may be expected. We also find that, for a decay constant slightly smaller than the Planck scale, the peak value of dark energy density is significantly smaller than the anthropic bound on the cosmological constant and can be close to the observed value. These outcomes are intriguingly consistent with recent DESI hints of time-varying dark energy, and offer a compelling anthropic explanation within the $\Lambda$ + axion framework.

    hep-phastro-ph.COPRD(2025)·8 citations
12. 12*

    Amplitudes and partial wave unitarity bounds

    Luigi C. Bresciani🇮🇹 · Gabriele Levati🇨🇭 · Paride Paradisi🇮🇹

    We develop a formalism, based on spinor-helicity techniques, to generalize the formulation of partial wave unitarity bounds. We discuss unitarity bounds for $N\to M$ (with $N,M\ge 2$) scattering processes -- relevant for high-energy future colliders -- and spin-2 or higher-spin theories -- relevant for effective field theories of gravity -- that are not approachable by standard methods. Moreover, we emphasize the power and complementarity of positivity and partial wave unitarity bounds to constrain the parameter space of effective field theories.

    hep-phhep-thPRD(2026)·16 citations
13. 13*

    A two-component dark matter model with $Z_2\times Z_4$ symmetry

    XinXin Qi🇨🇳 · Hao Sun🇨🇳

    We consider a two-component dark matter model with $Z_2\times Z_4$ symmetry, where a singlet scalar $S$ and a Majorana fermion $\chi$ are introduced as dark matter candidates. We also introduce another singlet scalar $S_0$ with a non-zero vacuum expectation value to the SM so that the fermion dark matter can obtain mass after spontaneous symmetry breaking. We have a new Higgs boson in the model and in the case of the decoupling limit, the fermion dark matter production is only determined by $S$ and the new Higgs boson. The mass hierarchy of these new particles can make a difference in the reaction rate of dark matter annihilation processes, contributing to different viable parameter spaces for different mass orderings. We randomly scanned the parameter space with six various cases under relic density constraint and found that when $\chi$ is the lightest among the dark sector, $\chi$ production is generated via the so-called forbidden channels. Moreover, we consider the combined limits arising from Higgs invisible decay, dark matter relic density and direct detection constraints. Within the chosen parameter space, direct detection results put the most stringent constraint, and we have a more flexible value for the scalar dark matter mass when the mass of $\chi$ is not smaller than the new Higgs boson mass.

    hep-phJCAP(2025)·5 citations
14. 14*

    Phenomenology of Inverse Seesaw Using $S_3$ Modular Symmetry

    Mitesh Kumar Behera🇹🇭 · Pawin Ittisamai🇹🇭 · Chakrit Pongkitivanichkul🇹🇭 · Patipan Uttayarat🇹🇭

    Describing neutrino masses using the inverse seesaw mechanism with discrete flavor symmetry imposed through modular forms provides a testable framework at TeV scales with fewer parameters. However, $S_3$, the smallest modular group, remains relatively underexplored. In this work, we construct the minimal supersymmetric inverse seesaw model based on the modular $S_3$ flavor symmetry. In our model, the light neutrino mass matrix depends on 6 real parameters: the complex modulus, an overall scale for light neutrino mass, a real ratio and a complex ratio of Yukawa coupling. Thanks to its minimality, our model offers various definite predictions: the lightest neutrino is massless, the neutrino masses are inverted ordering, the sum of the three light neutrino masses (${\sum }_i{m}_i$) is 100 meV, the effective mass for the end point of the beta decay spectrum is 50 meV, the effective mass for neutrinoless double beta decay ($m_{ee}$) is in the range $38-58$ meV. In particular, the predicted values for ${\sum }_i{m}_i$ and $m_{ee}$ from our model are within reach of the next generation experiments. Our model also predicts radiative lepton flavor violating decays $\ell \to {\ell }^{\prime }\gamma$ which are compatible with experimental constraints.

    hep-phEPJC(2025)·7 citations
15. 15*

    Lee Yang edge singularities of QCD in association with Roberge-Weiss phase transition and chiral phase transition

    Zi-yan Wan🇨🇳 · Yi Lu🇨🇳 · Fei Gao🇨🇳 · Yu-xin Liu🇨🇳

    We study the Quantum Chromodynamics (QCD) phase transitions in the complex chemical potential plane in the framework of Dyson-Schwinger equation approach, in the presence of a constant gluonic background field that represents confining dynamics. We solve the quark gap equation and the background field equation self consistently, which allows us to directly explore the confinement phase transition and furthermore, evaluate the impact of the back-coupling of confinement on chiral symmetry breaking. Moreover, within such a coupled framework towards the complex chemical potential region, we demonstrate the emergence of Roberge-Weiss (RW) symmetry and investigate the trajectory of Lee-Yang edge singularities (LYES). Our analysis reveals that the LYES scaling behavior is similar to our previous findings without the background field condensate. However, a significant difference from our earlier work is that the trajectory of LYES terminates when the imaginary part of the singularity becomes $1/3\pi T$. We elaborate that this cut-off behavior is caused by the RW symmetry that is symmetric to the imaginary chemical potential ${\mu }_i=1/3\pi T$.

    hep-phhep-thnucl-thPRD(2025)·8 citations
16. 16*

    Weizsäcker-Williams Gluon Helicity Distribution and Inclusive Dijet Production in Longitudinally Polarized Electron-Proton Collisions

    Yuri V. Kovchegov🇺🇸 · Ming Li🇺🇸

    It is well-known that the back-to-back (correlation) limit of inclusive quark-antiquark dijet production in unpolarized high energy electron-proton collisions can probe the Weizsäcker-Williams (WW) gluon transverse momentum-dependent distribution (TMD) at small $x$ \cite{Dominguez:2010xd, Dominguez:2011wm}. In this paper, we consider a helicity-dependent version of the same process: we study the double-spin asymmetry for inclusive quark-antiquark dijet production in longitudinally polarized electron-proton scattering at high energies. We show that in the back-to-back limit this process probes the WW gluon helicity TMD. Furthermore, we derive the small-$x$ evolution equation for the operator related to the WW gluon helicity distribution. We find that in the double-logarithmic approximation and in the large-$N_c$ limit, the small-$x$ asymptotics of the WW gluon helicity distribution is governed by exactly the same evolution equation as that for the dipole gluon helicity distribution. The longitudinal double-spin asymmetry for inclusive dijet production in the longitudinally polarized electron-proton collisions can thus test the small-$x$ helicity evolution equations and facilitate constraining the initial conditions for phenomenology based on these equations.

    hep-phJHEP(2025)·13 citations
17. 17*

    Detecting light dark matter with prompt-delayed events in neutrino experiments

    Yuanlin Gong🇨🇳 · Feiran Lin🇨🇳 · Ning Liu🇨🇳 · Liangliang Su🇨🇳 · Lei Wu🇨🇳

    We demonstrate the prompt-delayed signals induced by knockout neutrons from the quasi-elastic scattering in neutrino experiments provides a new avenue for detecting light dark matter. As an illustration, we consider the detection of atmospheric dark matter in the liquid scintillator detectors. The results show that the constraint on the DM-nucleon interaction from KamLAND is approximately one order of magnitude more stringent than those obtained from the elastic nuclear recoil signals in dark matter direct detection experiments. Furthermore, a larger volume neutrino experiment, such as JUNO, is expected to significantly enhance the light dark matter detection sensitivity through the quasi-elastic scattering.

    hep-phastro-ph.COJCAP(2026)·8 citations
18. 18*

    Two-loop Feynman integrals for leading colour $t\bar{t}W$ production at hadron colliders

    Matteo Becchetti🇮🇹 · Dhimiter Canko🇮🇹 · Vsevolod Chestnov🇮🇹 · Tiziano Peraro🇮🇹 · Mattia Pozzoli🇮🇹 · Simone Zoia🇨🇭

    We compute a complete set of the two-loop Feynman integrals that are required for the next-to-next-to-leading order QCD corrections to on-shell top-pair production in association with a $W$ boson at hadron colliders in the leading colour approximation. These Feynman integrals also contribute to Higgs or $Z$-boson production in association with a top pair. We employ the method of differential equations (DEs), facilitated by the use of finite field methods to handle the algebraic complexity stemming from the seven-scale kinematics. The presence of the top quark in the virtual propagators, in addition to the mass of the external $W$ boson, gives rise to nested square roots and three elliptic curves. We obtain DEs that depend at most quadratically on the dimensional regulator $ϵ$ for sectors where these analytic structures appear, and are $ϵ$-factorised otherwise. We express the DEs in terms of a minimal set of differential one-forms, separating the logarithmic ones. We solve the DEs numerically in the physical kinematic region, with the method of generalised power series expansions.

    hep-phhep-thJHEP(2025)·24 citations
19. 19*

    Extended scalar sectors from all angles (in 15 minutes)

    Tania Robens🇭🇷

    In this proceedings contribution, I briefly summarize various aspects that are important in the discussions of new physics searches with novel scalar states, at current and future colliders. In particular, I give a brief glance on the status of two Higgs doublet models, and discuss multi-scalar production as well as interference effects in Di-Higgs searches. I also mention searches of new scalar final states at possible Higgs factories.

    hep-ph4 citations
20. 20*

    Probing CP-Violating Neutral Triple Gauge Couplings at Electron-Positron Colliders

    John Ellis🇬🇧 · Hong-Jian He🇨🇳 · Rui-Qing Xiao🇨🇳

    We study the CP-violating (CPV) neutral triple gauge couplings (nTGCs) that can be realized via dimension-8 operators in the Standard Model Effective Field Theory (SMEFT). We present a new formulation of the CPV nTGC form factors that is compatible with spontaneous breaking of the electroweak gauge symmetry, and show how these CPV form factors can be matched consistently with the corresponding dimension-8 CPV nTGC operators in the broken phase. We then study probes of the CPV nTGCs at future high-energy $e^{+}{e}^{-}$ colliders with centre-of-mass energies $\sqrt{s}=(0.25,0.5,1,3,5)$TeV respectively, demonstrating that the $e^{\mp }$ beam polarizations can help to improve the sensitivities of probes of the nTGCs. We estimate that the sensitivity reaches for probing the new physics scales of nTGCs can range from $O(\mathrm{TeV})$ at a 250GeV $e^{+}{e}^{-}$ collider to $O(10\mathrm{TeV})$ at an $e^{+}{e}^{-}$ collider of energy $(3-5)$TeV, and that the sensitivities to the nTGC form factors vary from $O(10^{-4})$ to $O(10^{-6}-10^{-8})$ for the $e^{+}{e}^{-}$ collision energy from 250GeV to $(3-5)$TeV.

    hep-phhep-exSCPMA(2025)·11 citations
21. 21*

    Bayesian model-data comparison incorporating theoretical uncertainties

    Sunil Jaiswal🇺🇸 · Chun Shen🇺🇸 · Richard J. Furnstahl🇺🇸 · Ulrich Heinz🇺🇸 · Matthew T. Pratola🇺🇸

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

    hep-phnucl-thphysics.data-anPLB(2025)·7 citations
22. 22*

    IR fixed point and low-momentum gluon propagator

    Vladimir A. Petrov🇷🇺

    Assuming the gluon propagator to be finite at $g_s^2/4\pi \equiv \alpha \to {\alpha }_{\ast }$, where ${\alpha }_{\ast }=\alpha (0)$, we derive its low-momentum asymptotics. In some cases the results modify the known ones. In our work, we also establish the field-theoretical nature of a universal phenomenological parameter introduced in works \cite{Alk} and determining the behaviour of Green's functions in the infrared region. The importance of studying the renormalization group parameters in the vicinity of the infrared stable point is emphasized.

    hep-phNPB(2026)·0 citations
23. 23*

    Radiative Symmetry Breaking with a Scale Invariant Seesaw

    Aqeel Ahmed🇩🇪 · Juan P. Garcés🇩🇪 · Manfred Lindner🇩🇪

    We study a scale invariant inverse seesaw model that radiatively generates the electroweak scale, the Standard Model (SM) neutrino masses, and stabilizes the electroweak vacuum. Previous studies have noted that the SM Higgs potential and the electroweak scale can be radiatively generated via the minimal seesaw mechanism. This scenario, called the ``Neutrino Option'', was UV-completed by a scale invariant framework. However, these models predict singlet neutrino and scalar masses at $10^7-10^9$ GeV, beyond any experimental reach and leave the electroweak vacuum meta/un-stable at high energies. In this work, we propose modifications to this framework that lower the singlet neutrino masses to experimentally accessible scales through an inverse seesaw mechanism, while fully stabilizing the electroweak vacuum with an additional singlet scalar. The possibility of generating the observed baryon asymmetry of the universe via leptogenesis is also explored.

    hep-phPRD(2025)·2 citations
24. 24*

    Darkness in the Crust: Searching for the truly "Dark" Subhalos with Paleo-detectors

    Xiuyuan Zhang🇺🇸 · Lina Necib🇺🇸 · Denis Erkal🇬🇧

    Low-mass dark matter (DM) subhalos are pivotal in understanding the small-scale structure of the universe, thereby offering a sensitive method to discriminate between different cosmological models. In this study, we estimate the local number density of cold DM subhalos in the solar neighborhood, and demonstrate that their sparse distribution makes their detection via direct detection experiments highly improbable. However, it is plausible to expect that an $\mathcal{O}(1)$ number of subhalos could be detected by Paleo-detectors, a proposed new technique to look for DM by reading out damage tracks left by past DM interactions in minerals, due to their extended exposure times. Hence, we explore how Paleo-detectors can serve as effective probes for the properties of low-mass subhalos, $\mathcal{O}(10^{-5}-10^8)M_{\odot }$. We find that Paleo-detectors might be able to constrain certain regions of the subhalo mass-concentration relation (for subhalo masses of $10-10^4{M}_{\odot }$ if DM has a mass of $\sim 5$GeV). This is a new and complementary type of study that seeks to combine information from the particle nature of DM to that of small scale structures.

    hep-phastro-ph.COastro-ph.GA3 citations
25. 25*

    Weakly supervised anomaly detection with event-level variables

    Liam Brennan🇺🇸 · Tamas Almos Vami🇺🇸 · Oz Amram🇺🇸 · Sanjana Sekhar🇺🇸 · Yuta Takahashi🇺🇸 · Louis Moureaux🇩🇪 · Manuel Sommerhalder🇩🇪 · Petar Maksimovic🇺🇸 · Tianji Cai🇺🇸 · Nathaniel Craig🇺🇸

    We introduce a new topology for weakly supervised anomaly detection searches, di-object plus~X. In this topology, one looks for a resonance decaying to two standard model particles produced in association with other anomalous event activity (X). This additional activity is used for classification. We demonstrate how anomaly detection techniques which have been developed for di-jet searches focusing on jet substructure anomalies can be applied to event-level anomaly detection in this topology. To robustly capture event-level features of multi-particle kinematics, we employ new physically motivated variables derived from the geometric structure of a collision's phase space manifold. As a proof of concept, we explore the application of this approach to several benchmark signals in the di-$\tau$ and di-$\mu$ plus~X final states. We demonstrate that our anomaly detection approach can reach discovery-level significances for signals that would be missed in a conventional bump-hunt approach.

    hep-phhep-exPRD(2025)·6 citations
26. 26*

    N-body simulations of dark matter-baryon interactions

    Moritz S. Fischer🇩🇪 · Klaus Dolag🇩🇪 · Mathias Garny🇩🇪 · Vera Gluscevic🇺🇸 · Frederick Groth🇩🇪 · Ethan O. Nadler🇺🇸

    Dark matter (DM) particles can interact with particles of the standard model. Although there are a number of constraints derived from direct and indirect detection experiments, the evolution of astrophysical objects could offer a promising probe. Obtaining predictions is challenging and primarily limited by our ability to simulate scattering between DM and baryonic particles within N-body and hydrodynamics simulations. We have developed the first scheme allowing for the simulation of these interacting dark matter (IDM) models, accurately accounting for their angular and velocity dependence, as well as the mass ratio between the DM and baryonic scattering partners. To describe DM-baryon interactions, we used an N-body code together with its implementation of smoothed-particle hydrodynamics and meshless finite mass. The interaction is realised in a pairwise fashion by creating a virtual scattering partner from the baryonic particle and allowing it to interact with a DM particle using a scattering routine initially developed for self-interacting dark matter (SIDM). After the interaction, the virtual particle is rejoined with the baryonic particle, fulfilling the requirements of energy and momentum conservation. Through several test problems, we demonstrated that we are able to reproduce the analytic solutions with our IDM scheme. This includes a test for scattering with a physical mass ratio of 1:1000, which is beyond the limits of SIDM simulations. We comment on various numerical aspects and challenges, and we describe the limitations of our numerical scheme. Furthermore, we study the impact of IDM on halo formation with a collapsing over-density. We find that it is possible to accurately model IDM within N-body and hydrodynamics simulations commonly used in astrophysics. Finally, our scheme allows for novel predictions to be made and new constraints on DM-baryon scattering to be set.

    ↳ astro-ph.COastro-ph.GAhep-phAstron.Astrophys.(2025)·10 citations
27. 27*

    Taming systematics in distance and inclination measurements with gravitational waves: role of the detector network and higher-order modes

    Adriano Frattale Mascioli🇮🇹 · Francesco Crescimbeni🇮🇹 · Costantino Pacilio🇮🇹 · Paolo Pani🇮🇹 · Francesco Pannarale🇮🇹

    Gravitational-wave (GW) observations of compact binaries have the potential to unlock several remarkable applications in astrophysics, cosmology, and nuclear physics through accurate measurements of the source luminosity distance and inclination. However, these parameters are strongly correlated when performing parameter estimation, which may hamper the enormous potential of GW astronomy. We comprehensively explore this problem by performing Bayesian inference on synthetic data for a network of current and planned second-generation GW detectors, and for the third-generation interferometer Einstein Telescope~(ET). We quantify the role of the network alignment factor, detector sensitivity, and waveform higher-order modes in breaking this degeneracy. We discuss the crucial role of the binary mass ratio: in particular, we find that ET can efficiently remove the error in the distance as long as the compact binary is asymmetric in mass.

    ↳ gr-qcastro-ph.HEhep-phPRD(2025)·6 citations
28. 28*

    Circular orbits and accretion disk around a deformed-Schwarzschild black hole in loop quantum gravity

    Kourosh Nozari🇮🇷 · Sara Saghafi🇮🇷 · Milad Hajebrahimi🇮🇷 · Kimet Jusufi🇲🇰

    In this paper, we study the motion of neutral and electrically charged particles in the vicinity of a deformed-Schwarzschild black hole inspired by Loop Quantum Gravity (LQG). To examine the motion of an electrically charged test particle, we propose an expression for electromagnetic 4-potential that contains the impacts of loop quantum gravity. This electromagnetic 4-potential satisfies approximately the covariant Maxwell's equations to first order in the loop quantum effects. We explore the effects of the loop quantum correction parameter on the particle geodesics. We investigate the innermost stable circular orbits (ISCOs) for both neutral and electrically charged particles in detail, demonstrating that the loop quantum parameter significantly influences on the ISCO radius, causing it to shrink. Finally, we explore the accretion disk around the loop quantum black hole. We delve into the electromagnetic radiation flux, temperature, differential luminosity, and the spectral luminosity as radiation properties of the accretion disk in detail. We show that the loop quantum correction parameter shifts the profile of the electromagnetic flux and accretion disk temperature towards the central object, leading to a slight increase in these quantities.

    ↳ gr-qchep-phhep-thPhys.Dark Univ.(2025)·11 citations
29. 29*

    Axion generation and detection in laser-plasma wakefields

    Xiangyan An🇨🇳 · Min Chen🇨🇳 · Jianglai Liu🇨🇳 · Zhan Bai🇨🇳 · Liangliang Ji🇨🇳 · Zhengming Sheng🇨🇳 · Jie Zhang🇨🇳

    The axions are compelling candidates for cold dark matter, but their extremely weak interaction with photons makes laboratory searches challenging. We show that the quasi-static electromagnetic fields of a laser-plasma wakefield, which can exceed $10^{11}$\,V/m, enable axion generation without an external production magnet and enhance the conversion rate by two orders of magnitude over a conventional magnetic production region. Self-consistent particle-in-cell simulations reveal two complementary routes to detection. In the first route, axions are reconverted into photons within the wakefield and laser fields, eliminating the need for a separate regeneration magnet but requiring to suppress the intense laser-plasma background. The regenerated photons have polarization, harmonic-frequency, and Laguerre-Gaussian transverse-mode signatures that are largely absent from the driving fields, allowing successive filters to isolate the signal. In the second route, axions traverse a wall and undergo reconversion in a downstream magnet, providing a much lower background at the cost of requiring both the magnet and a seed pulse for coherent amplification. For axion masses below $0.1$\,meV, meter-scale wakefield guiding under our stated assumptions yields a projected coupling sensitivity down to $3.9\times 10^{-12}{\mathrm{GeV}}^{-1}$, surpassing the projected constraint of next-generation laboratory searches. These results establish ultra-strong plasma wakefields as a magnet-free axion source with two experimentally distinct and complementary detection strategies.

    ↳ physics.plasm-phhep-ph4 citations
30. 30*

    Testing the Shock-cooling Emission Model from Star-Disk Collisions for Quasiperiodic Eruptions

    Wenyuan Guo (SYSU)🇨🇳 · Rong-Feng Shen (SYSU)

    Quasiperiodic eruptions (QPEs), the repeated outbursts observed in soft X-ray bands, have attracted broad interest, but their physical origin is under debate. One of the popular models, the star-disk collision model, suggests that QPEs can be produced through periodic collisions of an orbiting star with the accretion disk of a central black hole (BH). However, previous tests of the star-disk collision model mainly focus on the timing analysis. Other observed properties, such as peak luminosities $L_{\mathrm{p}}$, durations $t_{\mathrm{e}}$, and radiation temperatures $T_{\mathrm{p}}$ of the eruptions, are not systematically investigated. For a sample of six QPE sources and two QPE-like sources, we test the shock-cooling emission model from star-disk collisions by using these observables to derive the constraints on the stellar radius $R_{\star }$. We find that, except for two sources (eRO-QPE3 and eRO-QPE4), the rest of the sample either has no allowed $R_{\star }$ to simultaneously reproduce the observed $L_{\mathrm{p}}$ and $t_{\mathrm{e}}$, or the required $R_{\star }$ is too large to avoid being disrupted by the central BH. For the two exceptions, a stellar radius of the order of $1R_{\odot }$ is necessary to satisfy all the constraints. Another issue with the simplest version of this model is that it predicts $k{T}_{\mathrm{p}}\sim 10\mathrm{eV}$, one order of magnitude lower than the observed value.

    ↳ astro-ph.HEastro-ph.GAastro-ph.SRhep-phApJ(2026)·14 citations
31. 31*

    Palatini Linear Attractors Are Back in ACTion

    Christian Dioguardi🇪🇪 · Alexandros Karam🇪🇪

    Recent results from the Atacama Cosmology Telescope (ACT) indicate a scalar spectral index $n_s\simeq 0.9743$, in excellent agreement with the prediction of linear inflation. However, the corresponding tensor-to-scalar ratio $r\simeq 0.0667$ is in tension with current observational bounds. In this work, we investigate how this tension can be alleviated in the Palatini formulation of gravity. We consider two classes of models based on simple monomial potentials: (i) models with a non-minimal coupling between the inflaton and gravity, and (ii) models including an $\alpha R^2$ term. In the first case, we find that a quadratic potential with a linear non-minimal coupling leads to the linear inflation attractor, with $r$ suppressed as $\xi$ increases. In the second case, we show that a linear potential can yield values of $r$ consistent with observations for sufficiently large $\alpha$. Our results demonstrate that simple monomial models can remain compatible with current observational constraints when embedded in the Palatini framework.

    ↳ gr-qcastro-ph.COhep-phPRD(2025)·51 citations
32. 32*

    Input to the ESPPU 2026 update: Searching for millicharged particles with the FORMOSA experiment at the CERN LHC

    Matthew Citron (1)🇺🇸 · Frank Golf (2)🇺🇸 · Kranti Gunthoti (3)🇺🇸 · Andrew Haas (4)🇺🇸 · Christopher S. Hill (5)🇺🇸 · Dariush Imani (6) · Samantha Kelly (1)🇺🇸 · Ming Liu (3)🇺🇸 · Steven Lowette (7)🇧🇪 · Albert De Roeck (8)🇨🇭 · Sai Neha Santpur (6) · Ryan Schmitz (6) and 6 other authors

    In this contribution, we evaluate the sensitivity for particles with charges much smaller than the electron charge with a dedicated scintillator-based detector in the far forward region at the CERN LHC, FORMOSA. This contribution will outline the scientific case for this detector, its design and potential locations, and the sensitivity that can be achieved. The ongoing efforts to prove the feasibility of the detector with the FORMOSA demonstrator will be discussed. Finally, possible upgrades to the detector through the use of high-performance scintillator will be discussed.

    ↳ hep-exhep-phphysics.ins-det6 citations
33. 33*

    Combination and interpretation of differential Higgs boson production cross sections in proton-proton collisions at $\sqrt{s}$ = 13 TeV

    CMS Collaboration

    Precision measurements of Higgs boson differential production cross sections are a key tool to probe the properties of the Higgs boson and test the standard model. New physics can affect both Higgs boson production and decay, leading to deviations from the distributions that are expected in the standard model. In this paper, combined measurements of differential spectra in a fiducial region matching the experimental selections are performed, based on analyses of four Higgs boson decay channels ($\gamma \gamma$, ZZ${}^{(\ast )}$, WW${}^{(\ast )}$, and $\tau \tau$) using proton-proton collision data recorded with the CMS detector at $\sqrt{s}$ = 13 TeV, corresponding to an integrated luminosity of 138 fb${}^{-1}$. The differential measurements are extrapolated to the full phase space and combined to provide the differential spectra. A measurement of the total Higgs boson production cross section is also performed using the $\gamma \gamma$ and ZZ decay channels, with a result of 53.4 ${}_{-2.9}^{+2.9}$ (stat) ${}_{-1.8}^{+1.9}$ (syst) pb, consistent with the standard model prediction of 55.6 $\pm$ 2.5 pb. The fiducial measurements are used to compute limits on Higgs boson couplings using the $\kappa$-framework and the SM effective field theory.

    ↳ hep-exhep-phJHEP(2026)·14 citations
34. 34*

    Absorption of Fermionic Dark Matter in the PICO-60 C${}_3$F${}_8$ Bubble Chamber

    E. Adams🇨🇦 · B. Ali🇨🇿 · R. Anderson-Dornan🇲🇽 · I. J. Arnquist🇺🇸 · M. Bai🇩🇪 · D. Baxter🇺🇸 · E. Behnke🇺🇸 · B. Broerman🇨🇦 · C. J. Chen🇺🇸 · K. Clark🇨🇦 · J. I. Collar🇺🇸 · P. S. Cooper🇺🇸 and 49 other authors

    Fermionic dark matter absorption on nuclear targets via neutral current interactions is explored using a non-relativistic effective field theory framework. An analysis of data from the PICO-60 C${}_3$F${}_8$ bubble chamber sets leading constraints on spin-independent absorption for dark matter masses below 23 MeV/${\text{c}}^2$ and establishes the first limits on spin-dependent absorptive interactions. These results demonstrate the sensitivity of bubble chambers to low-mass dark matter and underscore the importance of absorption searches in expanding the parameter space of direct detection experiments.

    ↳ hep-exhep-phPRL(2025)·7 citations
35. 35*

    Constraints on Anisotropic Cosmic Birefringence from CMB B-mode Polarization

    A. I. Lonappan🇺🇸 · B. Keating🇺🇸 · K. Arnold🇺🇸

    Cosmic birefringence$-$the rotation of the polarization plane of light as it traverses the universe$-$offers a direct observational window into parity-violating physics beyond the Standard Model. In this work, we revisit the anisotropic component of cosmic birefringence, which leads to the generation of $B$-mode polarization in the cosmic microwave background (CMB). Using an exact theoretical treatment beyond the thin last-scattering surface approximation, we constrain the amplitude of anisotropic birefringence with combined polarization data from SPTpol, ACT, POLARBEAR, and BICEP. The joint analysis yields a best-fit amplitude of $A_{\mathrm{CB}}=0.42_{-0.34}^{+0.40}\times 10^{-4}$, consistent with zero within $2\sigma$, and we place a 95\% confidence-level upper bound of $A_{\mathrm{CB}}<1\times 10^{-4}$. The constraint is not dominated by any single experiment and remains robust under the inclusion of a possible isotropic rotation angle. These results provide leading constraints on anisotropic cosmic birefringence from CMB $B$-mode polarization and illustrate the potential of upcoming experiments to improve sensitivity to parity-violating effects in the early universe.

    ↳ astro-ph.COgr-qchep-phPRD(2025)·10 citations
36. 36*

    Gravitational wave anisotropies from axion inflation

    Sofia P. Corbà🇺🇸

    An important prediction of inflation is the production of a primordial stochastic gravitational wave background. Observing this background is challenging due to the weakness of the signal and the simultaneous presence of an astrophysical background generated by many unresolved late-time sources. One possible way to distinguish between the two is to examine their anisotropies. In this paper we calculate the primordial correlation function of gravitational wave anisotropies in the cosmological background generated by axion inflation, where the inflaton is a pseudo-Nambu-Goldstone boson coupled to gauge fields. In this scenario, tensor modes arise not only from the standard amplification of vacuum fluctuations present in any inflationary model, but also from the inverse decay process of the produced gauge fields. The correlator of gravitational wave anisotropies consists therefore of two main components: the contribution from vacuum tensor modes and the contribution from tensor modes sourced by the gauge fields. Our analysis shows that, while the former, previously studied in the literature, is negligible, the one arising from the sourced tensor modes, normalized by the fractional energy density at interferometer frequencies, can reach values as large as $\mathcal{O}(10^{-1})$. This result shows that axion inflation can generate large anisotropies with the potential to be observed by gravitational wave detectors within a reasonable time frame.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2026)·5 citations
37. 37*

    Light Scalar Fields Foster Production of Primordial Black Holes

    Dario L. Lorenzoni🇨🇦 · Sarah R. Geller🇺🇸 · Zachary Ireland🇨🇦 · David I. Kaiser🇺🇸 · Evan McDonough🇨🇦 · Kyle A. Wittmeier🇨🇦

    Scalar fields are ubiquitous in theories of high-energy physics. In the context of cosmic inflation, this suggests the existence of spectator fields, which provide a subdominant source of energy density. We show that spectator fields boost the inflationary production of primordial black holes, with single-field ultra-slow roll evolution supplanted by a phase of evolution along the spectator direction, and primordial perturbations amplified by the resulting multifield dynamics. This generic mechanism is largely free from the severe fine-tuning that afflicts single-field inflationary PBH models.

    ↳ astro-ph.COgr-qchep-phhep-th11 citations
38. 38*

    Superheavy Dark Matter from the String Theory Axiverse

    Siyang Ling🇺🇸 · Andrew J. Long🇺🇸 · Evan McDonough🇨🇦 · Alex Hayes🇨🇦

    We propose heavy axions as a natural superheavy dark matter candidate in string theory, with the relic density of dark matter originating in quantum fluctuations during cosmic inflation. String Theory is well known for the possibility of having tens to hundreds of axion-like particles -- the axiverse. Moduli stabilization generates high-scale masses for many of these, placing them naturally in the superheavy regime of particle physics. We consider moduli stabilization in the KKLT framework, featuring a single volume modulus and $C_4$ axion, and a fiducial inflation model minimally coupled to the volume modulus. We demonstrate that both the volume modulus and the axion can be abundantly produced through gravitational particle production. The former is unstable and readily decays to Standard Model particles while the latter (the axion) can be stable and survives to constitute the present day dark matter.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2025)·8 citations
39. 39*

    Rapidity scan with DCCI at LHC energy

    Shin-ei Fujii🇯🇵 · Yasuki Tachibana🇯🇵 · Tetsufumi Hirano🇯🇵

    We extend the dynamical core-corona initialization (DCCI2) model to include the baryon number evolution in the entire system created in high-energy heavy-ion collisions. Introducing the source term for the baryon number, we describe the early-stage equilibration and later-stage hydrodynamic evolution of the baryon number throughout the system from midrapidity to forward rapidity. Through numerical simulations with this extended model, we show that extremely large baryon chemical potentials are realized in forward rapidity regions at the LHC energy and are comparable to those of the BES energies. Moreover, we show that fluctuations of baryon chemical potentials are large and, consequently, negative baryon chemical potential regions appear at midrapidity.

    ↳ nucl-thhep-phnucl-exJ.Subatomic Part.Cosmol.(2026)·1 citation

* 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.