Thu·Apr 9, 2026Thursday·April 9, 2026

1. 01*

   Exotic Higgs Decays at a Muon Collider

   JiJi Fan🇺🇸 · Lingfeng Li🇨🇳 · Tao Liu🇨🇳 · Yanhan Wang🇺🇸 · Mingrui Zhou🇨🇳

   We study the sensitivity of a future muon collider to exotic Higgs decays in a minimal scenario of Standard Model (SM) augmented with a light singlet scalar $S$. We consider the decay $h\to SS$ and $S$'s subsequently decay back to SM. In particular, we focus on final states with four bottom quarks ($4b$), or two bottom quarks and two muons ($2b2\mu$). Analyses are performed for two muon collider benchmark configurations: center-of-mass collision energy $\sqrt{s}=3\mathrm{TeV}$ with $1{\mathrm{ab}}^{-1}$ data and $\sqrt{s}=10\mathrm{TeV}$ with $10{\mathrm{ab}}^{-1}$ data. Machine-learning techniques are applied to suppress backgrounds and mitigate jet-combinatorics effects in both channels. We find that the $4b$ mode could be sensitive to the branching ratio, BR$(h\to SS\to 4b)$, of $\mathcal{O}(10^{-2})$ at 3 TeV and $\mathcal{O}(10^{-3})$ at 10 TeV, significantly improving upon high-luminosity LHC projections. In the Higgs-portal model with $S$ coupling to SM only through mixing with the Higgs, the sensitivities to BR$(h\to SS)$ remain at the same level given $\mathcal{O}(1)$ branching fraction of $S$ decaying into $b$-quarks. The $2b2\mu$ mode benefits from a clean dimuon resonance and can probe BR$(h\to SS\to 2b2\mu )$ down to $10^{-5}$ level at a 10 TeV muon collider. But the sensitivity to BR$(h\to SS)$ will be significantly reduced due to the small branching fraction of $S$ decaying into muons in the Higgs portal model.

   hep-ph1 citation
2. 02*

   Electron-positron pair production in strong oscillating electric field with multi-pulse structure

   Abhinav Jangir🇮🇳

   We investigate electron-positron pair production from the vacuum in presence of a strong oscillating electric field with a multi-pulse structure and variable inter-pulse delay. The pair production probabilities are computed by numerically solving the time-dependent Dirac equation. We analyze the resulting momentum distribution and the total number density of produced particles for different numbers of pulses and inter-pulse delays. In particular, we demonstrate the emergence of a characteristic time-domain multi-slit interference pattern in the pair production probability as a function of the inter-pulse delay.

   hep-ph0 citations
3. 03*

   Insights into 1-loop corrections to neutrino low-scale type-I seesaw mechanism

   Gennaro Miele🇮🇹 · Stefano Morisi🇮🇹 · Eduardo Peinado🇲🇽 · Kainat Qamar🇲🇽

   The standard type-I seesaw can also be regarded as a low-scale seesaw by using the freedom of the Casas-Ibarra parameterization. In this framework, radiative corrections to the neutrino mass matrix can dominate over the tree-level contribution. We show that a naive use of the Casas-Ibarra parametrization in the presence of 1-loop corrections leads to incorrect predictions for the neutrino oscillation parameters. By using a modified Casas-Ibarra parametrization, in which 1-loop corrections are reabsorbed into the right-handed neutrino mass matrix, we obtain a light neutrino mass matrix consistent with experimental values. On the other hand, we show that physical processes related to right-handed neutrino propagation, such as heavy neutral lepton searches, do not depend on the 1-loop corrections. Moreover, we show that $\mathrm{Br}(\mu \to e\gamma )$ provides competitive constraints on the parameter space of heavy neutral lepton search experiments for masses above $100$ GeV.

   hep-ph1 citation
4. 04*

   An A4 model to accommodate maximal theta23 and maximal delta consistent with mu-tau reflection symmetry

   Rupak Chakrabarty🇮🇳 · Chandan Duarah🇮🇳

   In this work, we construct an A4-based flavor symmetry model within the framework of the type-I seesaw mechanism to realize a light neutrino mass matrix consistent with mu-tau reflection symmetry. The entire framework is based on the Standard Model gauge symmetry extended by the discrete group A4 x Z2 x Z4. In general, the elements of the light Majorana neutrino mass matrix are complex. The mu-tau reflection symmetric texture of the mass matrix can be realized in a generalized CP symmetry limit. In this symmetry limit, the model predicts a maximal atmospheric mixing angle theta23 = pi/4 and a maximal Dirac CP phase delta = pi/2 or 3pi/2. These features are consistent with current experimental observations, including a near-maximal value of theta23, a non-zero reactor angle, and a preference for delta close to 270 degrees, as indicated by the T2K and NOvA experiments. Non-maximal values of theta23 and delta can be accommodated when one does not restrict to the CP symmetry limit. The model predictions for the mixing angles and the Dirac CP phase delta are then controlled by two parameters. We perform a numerical analysis to identify the allowed values of the model parameters consistent with current global three-neutrino oscillation data. The model successfully reproduces the desired deviations of theta23 and delta from their maximal values, consistent with global fit data, while simultaneously accommodating the observed values of theta12 and theta13.

   hep-phEPJC(2026)·0 citations
5. 05*

   Diffusion-Based Point-Cloud Generation of Heavy-Ion Events

   Rita Sadek🇺🇸 · Vinicius Mikuni🇯🇵 · Mateusz Ploskon🇺🇸

   Heavy-ion collisions produce final states with thousands to tens of thousands of particles, making their simulation among the most computationally intensive tasks in high-energy nuclear physics. We present a fast, high-fidelity generative model for heavy-ion events based on a score-driven diffusion process and the Point-Edge Transformer architecture within the OmniLearn framework. A two-stage training strategy is performed: Stage-1 training on lower-multiplicity O-O collisions allowing the model to learn a stable event and particles representation, followed by fine-tuning on challenging high-multiplicity Pb-Pb collisions. We benchmark the generator with a broad set of closure checks, including agreement of event- and particle-level observables in one and two dimensions, flow consistency reconstructed from the generated particles, end-to-end jet finding with FastJet including key jet and substructure observables, and a classifier-based application to quantify the sample fidelity. The results are promising, showing that a compact generative model can produce realistic, high-multiplicity heavy-ion events, at a level that makes local-scale generation for heavy-ion collisions at high energies a practical goal.

   hep-phhep-exnucl-exPRC(2026)·0 citations
6. 06*

   Low-Scale Leptogenesis from Resonant Thermal Lepton Flavour Coherences

   Shao-Ping Li🇯🇵 · Apostolos Pilaftsis🇬🇧

   Resonant heavy-neutrino mixing and sterile neutrino oscillations are two prominent mechanisms to realize low-scale leptogenesis, with singlet neutrino masses below TeV energies that could be probed in current and future laboratory experiments. In their minimal settings, both mechanisms require a significant degree of degeneracy in the singlet neutrino masses to compensate for the suppression that results from the small neutrino Yukawa couplings. After further developing the flavour-covariant Kadanoff-Baym formalism, we study in detail a novel dominant mechanism for low-scale leptogenesis which becomes greatly enhanced by resonant thermal lepton-flavour coherences at the two-loop level. This mechanism works successfully for both Dirac and Majorana singlet neutrinos, and it does not rely on whether these singlet neutrinos are quasi-degenerate or not. In particular, it implies that successful low-scale leptogenesis in the type-I seesaw framework can be naturally realised with heavy neutrino masses that could be as low as GeV.

   hep-ph2 citations
7. 07*

   Distribution amplitudes and functions of ground-state scalar and pseudoscalar charmonia

   X.-Y. Zeng🇨🇳 · Y.-Y. Xiao🇨🇳 · Z.-N. Xu🇪🇸 · C. D. Roberts🇨🇳 · J. Rodríguez-Quintero🇪🇸

   Charmonia are often supposed to provide simple hydrogen-like ``atomic'' systems that can be used to obtain insights into heavier-quark QCD. We use continuum Schwinger function methods to analyse this hypothesis in connection with ground-state scalar and pseudoscalar charmonia and find that a more complex picture of these states may be necessary. For instance, considering orbital angular momentum, the ${\chi }_{c0}$ is not a simple $P$-wave system; similarly, the ${\eta }_c$ wave function contains more than merely $S$-wave contributions. The distribution amplitudes (DAs) and distribution functions (DFs) of these mesons are also nontrivial. For instance, the ${\chi }_{c0}$ DA is not positive definite: owing to QCD symmetries, it possesses domains of balanced negative and positive support. This feature is also expressed in the ${\chi }_{c0}$ DF, but differences between ${\chi }_{c0}$ and ${\eta }_c$ DFs diminish under scale evolution. Notably, the light-front momentum fraction carried by glue is the same in both states: it is 10\% less than the in-pion glue momentum fraction. Whilst experimental confirmation of the predictions herein is unlikely, our results should serve as benchmarks for complementary theory attempts to understand local and global structural features of heavier-quark hadrons.

   hep-phhep-exhep-latnucl-ex+12 citations
8. 08*

   The non-topological $Z^{\prime }$ string in the 331 model and its classical stability

   Zhengyang Bian🇨🇳 · Ning Chen🇨🇳 · Mian Guo🇨🇳 · Zhanpeng Hou🇨🇳 · Haoyang Ji🇨🇳 · Junyi Wei🇨🇳 · Zhuo Zhang🇨🇳

   We study the classical stability of a non-topological $Z^{\prime }$ string in the minimal 331 model, which arises from the maximal symmetry breaking pattern of an $\mathrm{SU}(6)$ toy model. Two Higgs triplets are introduced according to the emergent global symmetries in the fermionic sector of the $\mathrm{SU}(6)$ toy model, which will achieve the sequential symmetry breaking of $\mathrm{SU}(3{)}_c\otimes \mathrm{SU}(3{)}_W\otimes \mathrm{U}(1{)}_X\to \mathrm{SU}(3{)}_c\otimes \mathrm{SU}(2{)}_W\otimes \mathrm{U}(1{)}_Y$. By analyzing small perturbations around the string background and solving the coupled Helmholtz equations numerically, we find that the string is stable only near the semilocal limit of ${\vartheta }_S\approx \frac{\pi }{2}$, even when Higgs self-couplings are tuned to minimize instabilities. This suggests that such non-topological strings are unlikely to exist in unified theories based on $\mathrm{SU}(N>5)$ Lie algebras.

   hep-phhep-thEPJC(2026)·1 citation
9. 09*

   Quantum-Inspired Tensor Network Autoencoders for Anomaly Detection: A MERA-Based Approach

   Emre Gurkanli🇹🇷 · Michael Spannowsky🇩🇪

   We investigate whether a multiscale tensor-network architecture can provide a useful inductive bias for reconstruction-based anomaly detection in collider jets. Jets are produced by a branching cascade, so their internal structure is naturally organised across angular and momentum scales. This motivates an autoencoder that compresses information hierarchically and can reorganise short-range correlations before coarse-graining. Guided by this picture, we formulate a MERA-inspired autoencoder acting directly on ordered jet constituents. To the best of our knowledge, a MERA-inspired autoencoder has not previously been proposed, and this architecture has not been explored in collider anomaly detection. We compare this architecture to a dense autoencoder, the corresponding tree-tensor-network limit, and standard classical baselines within a common background-only reconstruction framework. The paper is organised around two main questions: whether locality-aware hierarchical compression is genuinely supported by the data, and whether the disentangling layers of MERA contribute beyond a simpler tree hierarchy. To address these questions, we combine benchmark comparisons with a training-free local-compressibility diagnostic and a direct identity-disentangler ablation. The resulting picture is that the locality-preserving multiscale structure is well matched to jet data, and that the MERA disentanglers become beneficial precisely when the compression bottleneck is strongest. Overall, the study supports locality-aware hierarchical compression as a useful inductive bias for jet anomaly detection.

   hep-phcs.LGquant-ph0 citations
10. 10*

    Higgs Bosons at 95 and 125 GeV in the $U(1{)}_X$VLFM

    Rong-Zhi Sun🇨🇳 · Shu-Min Zhao🇨🇳 · Meng-Zi Cao🇨🇳 · Song Gao🇨🇳 · Xing-Xing Dong🇨🇳

    We present a systematic analysis of the Higgs signal strengths at 125 GeV and 95 GeV in a non-supersymmetric $U(1{)}_X$ model with vector-like fermions ($U(1{)}_X$VLFM). This model extends the SM by introducing an additional $U(1{)}_X$ gauge symmetry, three right-handed neutrinos, two singlet Higgs fields ($\varphi$ and $S$), and one generation of vector-like quarks and leptons. The scalar fields mix with each other in the neutral CP-even sector, leading to two Higgs-like states around 95 GeV and 125 GeV. A ${\chi }^2$ analysis is performed by combining the Higgs signal strength measurements at 125 GeV from ATLAS and CMS, including the $\gamma \gamma$, $W{W}^{\ast }$, $Z{Z}^{\ast }$, $b\bar{b}$, and $\tau \bar{\tau }$ channels, with the 95 GeV excesses observed in the diphoton and $b\bar{b}$ final states reported by CMS and LEP. Our results indicate that the $U(1{)}_X$VLFM can successfully reproduce the observed signal strengths of the 125 GeV Higgs while simultaneously explaining the 95 GeV excess. The parameters $g_X$, $g_{YX}$, $v_S$, $v_P$, and the new Yukawa couplings play a crucial role in achieving this consistency.

    hep-phCPC(2026)·0 citations
11. 11*

    Memory-Burden Suppression of Hawking Radiation and Neutrino Constraints on Primordial Black Holes

    Arnab Chaudhuri🇮🇳

    We investigate the impact of quantum gravitational memory-burden effects on high-energy neutrino signals from evaporating primordial black holes and the resulting constraints from IceCube observations. Treating the backreaction as an energy-dependent deformation of the Hawking emission spectrum, we show that the high-energy tail is suppressed while the infrared behaviour remains unchanged. We derive analytically that this modification reduces the total luminosity and extends the evaporation lifetime by a mass-independent factor determined solely by the suppression parameter. Using an effective treatment of cosmological redshift, we compute the diffuse neutrino flux from a primordial black hole population and compare it with the observed astrophysical neutrino spectrum to constrain the primordial black hole dark matter fraction. We find that the suppression onset lies within the IceCube sensitivity window, leading to a direct reduction of the observable signal and a systematic weakening of the inferred bounds. Our results provide a controlled phenomenological framework for assessing the impact of quantum gravitational corrections on neutrino probes of primordial black hole evaporation.

    hep-ph1 citation
12. 12*

    Direct-detection constraints on inelastic dark matter with a scalar mediator

    I. V. Voronchikhin🇷🇺 · D. V. Kirpichnikov🇷🇺

    We calculate direct detection constraints on inelastic dark matter (DM) for a scalar portal scenario with leptophilic couplings. The p-wave velocity suppression of the annihilation cross section of scalar-mediated inelastic Dirac DM implies the opening of viable regions of DM parameter space in the MeV-GeV mass range. Xenon-based experiments can provide a constraints on scalar-mediated inelastic fermion dark matter for sub-MeV mass splitting, via endothermic and exothermic spin-independent DM-electron scattering. To estimate the relevant constraints, we use public data from the XENON1T, PandaX-4T, and LZ liquid-xenon experiments that measure ionization electron signals.

    hep-ph2 citations
13. 13*

    LHC signatures of a light pseudoscalar in a flipped two-Higgs scenario: the usefulness of boosted $b\bar{b}$ pairs

    Dilip Kumar Ghosh🇮🇳 · Biswarup Mukhopadhyaya🇮🇳 · Sirshendu Samanta🇮🇳 · Ritesh K. Singh🇮🇳

    Similar to some other two-Higgs doublet models (2HDM), the flipped 2HDM admits of a light pseudoscalar physical state whose mass can be well below 50 GeV. The fact that the pseudoscalar decays dominantly into a $b\bar{b}$ pair makes its identification at the Large Hadron Collider (LHC) difficult. Moreover, the regions of the parameter space corresponding to a light pseudoscalar tend to jeopardize perturbativity at a rather low scale. One possibility that ameliorates this problem is to postulate that the light physical state has the admixture of an SU(2) singlet field. In such a situation, however, the production mode of the pseudoscalar along with a $Z$ (which provides a useful tag) gets suppressed. We have here chosen to fall back on the QCD-driven final state, namely, one or two jets, together with an energetic squeezed $b\bar{b}$-pair. We utilize boosted di-b-jet tagging techniques and a strategy based on boosted decision trees (BDT) to analyze the signals, considering all backgrounds and likely fakes (mostly from charmed quarks). We find that, including 10\% systematics, one can expect signal significance of 5-10$\sigma$ with an integrated luminosity of 3 $a{b}^{-1}$.

    hep-ph1 citation
14. 14*

    Post-Inflationary Quenched Production of Axion SU(2) Dark Matter

    Imtiaz Khan🇨🇳 · Pirzada🇨🇳 · G. Mustafa🇨🇳

    The relic abundance of vector dark matter originating from an inherited axion-$SU(2)$ condensate is typically determined by implementing an adiabatic matching procedure across the symmetry-breaking transition. We demonstrate that this outcome does not arise in the generic case. The post-inflationary crossover can instead be formulated as a dynamical quantum quench problem, in which the residual coherent component of the field is characterized by a survival factor that induces an $\mathcal{O}(1)$ renormalization of the standard abundance relation. Expressed in conformal time, the spatially homogeneous condensate dynamics reduce to those of a canonical oscillator with quartic and quadratic self-interactions. This representation enables an analytic determination of the matching conditions across the symmetry-breaking transition, the derivation of the corresponding quench work and excess energy relations, and a quantitative validation of the coherent sector description via numerical simulations in both Minkowski and Friedmann--Robertson--Walker backgrounds. We also formulate the homogeneous fluctuation theory via the diagonal-$SO(3)$ $1\oplus 3\oplus 5$ decomposition and isolate a soft traceless-symmetric quintet with a $k=0$ vacuum obstruction, a regulated ultraviolet adiabatic bound, and a positive quartic stabilization term. Collectively, these results refine the theoretical description of inherited non-Abelian dark matter production and establish the necessary infrared framework for subsequent investigations of finite-$k$ gauge--Higgs transfer dynamics.

    hep-phPRD(2026)·10 citations
15. 15*

    Internal structure of light mesons using the power law wave function

    Satyajit Puhan🇮🇳 · Narinder Kumar🇮🇳 · Harleen Dahiya🇮🇳

    In this paper, we study the internal structure of light pseudoscalar mesons using spin improved power-law wave functions. We choose the pion and the kaon for our work. We use the standard quark-quark correlation functions to calculate the distribution amplitudes (DAs), parton distribution functions (PDFs), transverse momentum dependent parton distribution functions (TMDs), and generalized parton distribution functions (GPDs) at zero skewness and form factors. We present all the above distribution functions through the overlap of light-front wave functions (LFWFs). We use leading-order Efremov-Radyushkin-Brodsky-Lepage (ERBL) equations for DAs and next-to-leading-order (NLO) Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) equations for PDFs to evolve them to higher scales. We find that only 41\% of the longitudinal momentum fraction is carried by the quark and antiquark of both pion and kaon at 16~GeV${}^2$. The vector form factors for both the pion and the kaon are found to be in good agreement with experimental data. Similarly, the electromagnetic charge radii are found to be 0.668~fm and 0.704~fm for the pion and kaon, respectively.

    hep-ph0 citations
16. 16*

    LHC di-dijet excesses as signals of fourth-generation tetraquarks

    Hsiang-nan Li🇹🇼

    We postulate that the excesses of di-dijet events observed at the LHC are attributed to the production of four fourth-generation quarks $b^{\prime }$ with a mass $m_{b^{\prime }}\approx 2$ TeV at few-TeV scales. The di-dijet signals around the four-jet invariant mass $m_{4j}\approx 8$ TeV arise from a resonant $b^{\prime }{b}^{\prime }{\bar{b}}^{\prime }{\bar{b}}^{\prime }$ tetraquark production, where the dijet resonances of masses about 2 TeV correspond to $b^{\prime }{\bar{b}}^{\prime }$ first excited states (color-octet scalars with the principal quantum number $n=2$) in a Yukawa potential created by Higgs boson exchanges. Those around $m_{4j}\approx 3.6$ TeV originate from a non-resonant $b^{\prime }{b}^{\prime }{\bar{b}}^{\prime }{\bar{b}}^{\prime }$ production, where the dijet resonances of masses 0.95 TeV correspond to $b^{\prime }{\bar{b}}^{\prime }$ ground states (color-octet vectors with $n=1$). It is shown that a $b^{\prime }{\bar{b}}^{\prime }$ system with $m_{b^{\prime }}\approx 2$ TeV in the Yukawa potential does generate the aforementioned bound state spectrum. We then illustrate that the observed excesses can be accommodated in our setup by translating the fourth-generation model to the effective theories containing color-octet scalars and vectors available in the literature. The di-dijet events at $m_{4j}=6.6$ TeV and 5.8 TeV with dijet masses about 2 TeV can also be interpreted in the same framework. Simply speaking, our scenario can be viewed as a TeV-scale version of the search for a fully charmed tetraquark via the four-muon channels $X(6900)\to (c\bar{c})(c\bar{c})\to 4\mu$ at a GeV scale.

    hep-ph0 citations
17. 17*

    QED radiative corrections in inverse beta decay from virtual pions

    Oleksandr Tomalak🇨🇳

    Inverse beta decay (IBD), ${\overline{\nu }}_{e}p\to e^{+}n\left(\gamma \right)$, is the main detection channel for reactor and supernova antineutrinos. To provide precise IBD cross sections at antineutrino energies $E_{{\overline{\nu }}_e}\gtrsim 10\mathrm{MeV}$, we evaluate radiative corrections from virtual pions within the framework of heavy baryon chiral perturbation theory. At leading order, only the pion isospin-breaking contributions are not suppressed by the electron mass. At next-to-leading order, besides recoil effects, only the Wilson coefficient $c_4$ contributes to the kinematic dependence. However, its precise value is not relevant for IBD at relatively low energies since all next-to-leading order radiative corrections are relatively small. We find the kinematic dependence of the pion-induced QED radiative corrections at the level and below the uncertainty from the momentum dependence of the nucleon form factors. Our results enable sub-permille theoretical precision of charged-current elastic (anti)neutrino-nucleon scattering at antineutrino energies $E_{{\overline{\nu }}_e}\gtrsim 10\mathrm{MeV}$.

    hep-phhep-exnucl-exnucl-thJHEP(2026)·2 citations
18. 18*

    Impact of hidden heavy Higgs channels of VLB-Quarks below 1 TeV in 2HDM

    Rachid Benbrik🇲🇦 · Mbark Berrouj🇲🇦 · Mohammed Boukidi🇵🇱 · Mohamed Ech-chaouy🇲🇦 · Kholoud Kahime🇲🇦 · Khawla Salime🇲🇦

    We investigate the phenomenological impact of incorporating vector-like bottom (VLB) quarks into the Type-II Two-Higgs-Doublet Model (2HDM-II). This framework introduces novel beyond-Standard-Model (BSM) decay channels $B\to Hb$, $B\to Ab$, and $B\to H^{-}t$, which are typically ignored by LHC pair-production searches focused on Standard Model (SM) final states ($B\to Zb$, $B\to hb$, $B\to Wt$). Our analysis reveals that these BSM pathways significantly weaken current VLB mass constraints. In the 2HDM-II alignment limit, the mass limit for a singlet $B$ shifts from approximately 1.5 TeV down to 1.34 TeV. For $(T,B)$ and $(B,Y)$ doublet configurations, the mass limits relax further to approximately 0.98 TeV, driven by the dominance of $B\to Hb$ and $B\to Ab$ decays, which can reach combined branching ratios of nearly 100\%.

    hep-phNPB(2026)·2 citations
19. 19*

    Light mesons in the symmetric-vertex approximation

    M.N. Ferreira🇧🇷 · A.S. Miramontes🇪🇸 · J.M. Morgado🇪🇸 · J. Papavassiliou🇪🇸

    We compute the spectrum of light mesons, composed by up, down, and strange quarks, using a symmetry-preserving approximation that permits the inclusion of fully-dressed quark-gluon vertices in the key dynamical equations. This method is characterized by the use of the standard symmetric kinematic configuration as a seed in the corresponding Schwinger-Dyson equation, yielding finally the full kinematic dependence of all eight form factors composing the transversely-projected quark-gluon vertex. The extension of this approach to the case of distinct nonvanishing current quark masses is discussed, and the compatibility with the fundamental Ward-Takahashi identities demonstrated. The corresponding Bethe-Salpeter kernel is composed by three different diagrammatic structures, which may be deduced from the attendant quark gap equation by applying the standard "cutting" rules. The masses of the light mesons are computed by first determining the eigenvalue of the Bethe-Salpeter equation as a function of Euclidean momenta, and then using the Schlessinger extrapolation method to determine the Minkowski momentum for which this eigenvalue becomes unity. The resulting meson masses are in good agreement with experimental values, and substantially improve upon predictions from the rainbow-ladder approximation.

    hep-phhep-latnucl-thEPJC(2026)·8 citations
20. 20*

    Correlation function and bound state from the $K{D}_{s0}^{\ast }(2317)$ interaction

    Wen-Hao Jia🇨🇳 · Hai-Peng Li🇨🇳 · Wei-Hong Liang🇨🇳 · Jing Song🇨🇳 · Eulogio Oset🇪🇸

    In anticipation of the new wave of ALICE experiments on particle-resonance correlation functions, we study the interaction of a kaon with the $D_{s0}^{\ast }(2317)$ resonance. Assuming the $D_{s0}^{\ast }(2317)$ to be a $DK$ molecular state in isospin $I=0$, we employ the fixed center approximation (FCA) to describe the kaon scattering off the $DK$ cluster, and implement elastic unitarity in the $K{D}_{s0}^{\ast }(2317)$ amplitude via an optical potential and the Lippmann-Schwinger equation. We evaluate the scattering length, effective range, and correlation function, which exhibits a shape characteristic of a strongly attractive interaction. Notably, the amplitude develops a narrow resonant peak about 40~MeV below the $K{D}_{s0}^{\ast }(2317)$ threshold, signaling a three-body bound state. We discuss the experimental feasibility of observing this state through the invariant mass distribution of $K{D}_s^{+}{\pi }^0$, and argue that such three-body states, predicted by various theoretical approaches, offer promising targets for future experimental searches, providing valuable insights into the nature of exotic hadronic resonances.

    hep-phPRD(2026)·3 citations
21. 21*

    Constraining magnetic monopoles and multiply charged particles with diphoton events at the LHC

    Vasiliki A. Mitsou🇪🇸 · Emanuela Musumeci🇪🇸

    The LHC is achieving energies never reached before, opening up possibilities for the discovery of exotic particles in the TeV mass range. Such states include magnetic monopoles, which can explain the electric charge quantisation and restore the symmetry in Maxwell's equations with respect to the magnetic and electric fields. Scenarios proposed to shed light to dark matter and neutrino masses introduce high-electric-charge objects (HECOs). The existence of both classes of particles can be probed in precision measurements in a manner complementary to direct searches. We focus on the contributions of such virtual particles to light-by-light scattering in the context of effective field theories and a Born-Infeld scenario. Specifically, measurements of central exclusive production of photon pairs with proton tagging carried out by the CMS-TOTEM Precision Proton Spectrometer with LHC Run 2 proton-proton collision data are used to constrain magnetic monopole and HECOs. Resummation techniques have been employed to deal with the large HECO-photon coupling. Masses of up to a few tens of TeV have been excluded for monopoles and HECOs of various spins and magnetic and electric charges, respectively.

    hep-phhep-ex9 citations
22. 22*

    Analytic Approximations for Fermionic Preheating

    Heather E. Logan🇨🇦 · Daniel Stolarski🇨🇦 · Fazlul Yasin🇨🇦

    Non-thermal fermions can be produced non-perturbatively in the early universe during coherent oscillations of a scalar field. We explore fermion production in $\lambda {\varphi }^4$ inflation through this mechanism and analyze the momentum spectrum of the fermions produced, which depends on a coupling parameter $q$. For $q\gtrsim 0.01$, the main contribution to the total number density comes from an approximately half-filled Fermi sphere as a result of non-adiabaticity. For $q\lesssim 0.01$, we find that the major contributions instead come from resonance peaks at higher momentum values. We find a simple relation to predict the momentum values corresponding to resonance peaks for any $q$. We also obtain analytic power-law approximations for the total number density of fermions and find that it is proportional to $q^{1/2}$ for $q\lesssim 0.01$ and proportional to $q^{3/4}$ for $q\gtrsim 10$. If fermions produced by this mechanism make up the entirety of dark matter, we estimate lower bounds on their mass.

    hep-phastro-ph.CO0 citations
23. 23*

    Finite Volume Effects on Transverse Momentum Spectra at LHC and RHIC Using a Blast-Wave Model with Planck Transformed Temperatures

    A.S. Parvan🇷🇺 · A.A. Aparin🇷🇺 · E.V. Nedorezov

    We investigate finite volume effects on the transverse momentum spectra of charged pions produced in the most central heavy-ion collisions at RHIC and LHC energies. A cylindrically symmetric finite volume Boltzmann-Gibbs blast-wave model is employed that fully incorporates the finite longitudinal extent of the fire cylinder at kinetic freeze-out. The model applies Planck transformations to convert the local rest frame temperature and chemical potential of each fluid element into laboratory frame values, ensuring full Lorentz covariance. This approach is compared with the conventional infinite volume blast-wave model, in which the thermodynamic parameters remain defined in the local rest frame while the particle momenta are expressed in the laboratory frame. Both models are fitted to the experimental transverse momentum distributions of charged pions measured by the HADES, STAR, PHENIX, and ALICE collaborations over the center-of-mass energy range $\sqrt{s_{NN}}=2.4$ GeV to $5.44$ TeV. The finite volume model with Planck transformed laboratory frame parameters yields temperature values fully consistent with relativistic thermodynamics (except for a small anomaly at $\sqrt{s_{NN}}=193$ and $200$ GeV) and produces realistic fire cylinder volumes several times larger than the initial nuclear overlap volume. In contrast, the conventional infinite volume model yields unphysical results: infinite volume, infinite maximum half-length, and maximum longitudinal flow velocity equal to the speed of light at all energies. These findings demonstrate that a proper treatment of finite system size, together with the correct Lorentz (Planck form) transformation of the thermodynamic variables, is essential for the reliable extraction of freeze-out parameters in heavy-ion collisions.

    hep-ph2 citations
24. 24*

    Scalars at the Cosmological Collider: Full Shapes of Tree Diagrams and Bispectrum Searches using Planck Data

    Soubhik Kumar🇺🇸 · Qianshu Lu🇺🇸 · Zhong-Zhi Xianyu🇨🇳 · Yisong Zhang🇨🇳

    The Cosmological Collider (CC) provides a unique opportunity to probe the particle spectrum and fundamental interactions at extremely high energies. Massive particles, via their decay into inflaton quanta, can induce a non-analytic, oscillatory, primordial non-Gaussianity (NG), including the bispectrum. At tree level, three classes of such processes contribute to the bispectrum: 'single exchange', 'double exchange', and 'triple exchange', depending on the number of massive particle propagators. We provide a unified evaluation of all three diagrams and derive the explicit shape functions for the bispectrum, valid across the entire kinematic space. We perform a search for these three processes with the Planck data, finding no evidence for NG. We also consider simple extensions of the minimal scenario that can counter the exponential suppression of the non-analytic signature, and produce on-shell particles with masses $M\gg H$, the Hubble scale during inflation. In particular, we focus on the 'scalar chemical potential' mechanism and extend our previous search to a wider range of chemical potential ($\omega$) and $M$, finding global 1.5$\sigma$ evidence for non-zero NG for the parameter space $\omega -M\simeq 3H$.

    hep-phastro-ph.COhep-th13 citations
25. 25*

    Gauged Q-balls in flat potentials

    Julian Heeck🇺🇸 · Yu Zhi🇺🇸

    Q-balls are large bound-state systems of scalar particles, described classically through localized solutions of the equations of motion. Promoting the required stabilizing U(1) symmetry to a gauge symmetry leads to gauged Q-balls, which cannot grow beyond some maximal size and charge on account of the repulsive gauge interactions. These gauged Q-balls have been studied extensively for scalar potentials that satisfy Coleman's thin-wall criterion; here, we explore gauged Q-balls in flat potentials, which often occur in supersymmetric models. Even though global Q-balls in flat potentials are qualitatively different from Coleman's Q-balls, we find that the gauged versions are remarkably similar. We provide analytic approximations for these solitons and compare to numerical solutions. In addition, we study Proca Q-balls, i.e. make the gauge bosons massive, which interpolates between the global and gauged cases.

    hep-phhep-thPRD(2026)·0 citations
26. 26*

    GOOFy fermions

    P.M. Ferreira🇵🇹

    A new class of symmetries of two Higgs doublet models was recently discovered, the result of an unorthodox transformation on scalar and gauge fields and spacetime coordinates. It was explicitly shown that it is possible to choose Yukawa matrix textures which respect those symmetries up to two-loops. In this work we will establish the fermion field transformations for the two Higgs doublet models to be considered in the context of the new symmetries established. New regions of parameter space, invariant under renormalization to all orders of perturbation theory, are discovered, including scalar-fermion interactions.

    hep-phJHEP(2026)·2 citations
27. 27*

    Neutrino transport and flavor instabilities in a post-merger disk

    Erick Urquilla🇺🇸 · Swapnil Shankar🇩🇪 · Debraj Kundu🇺🇸 · Julien Froustey🇪🇸 · Sherwood Richers🇺🇸 · Jonah M. Miller🇺🇸 · Gail C. McLaughlin🇺🇸 · James P. Kneller🇺🇸 · Francois Foucart🇺🇸

    Neutron star mergers are multimessenger sources whose dynamics and signals depend critically on neutrinos and their flavor transformations. We investigate whether fast and collisional neutrino flavor instabilities (FFIs and CFIs) arise in a GW170817-like post-merger accretion disk, and how they develop and relax, by performing global and local classical and quantum-kinetic simulations that resolve anisotropies and inhomogeneities in the full six-dimensional phase space. In the accretion disk, the neutrino radiation field naturally develops electron-lepton-number crossings through the interplay between the more isotropic electron neutrino field and the more anisotropic electron antineutrino field. The neutrino field in the disk is also unstable to CFI, although on longer timescales than the FFI. Using local, multi-energy quantum-kinetic calculations at selected points, we find that the growth of unstable modes is well-predicted by a fully anisotropic linear stability analysis and the flavor transformation increases the heavy lepton neutrino fluxes. CFI likewise enhances heavy-flavor fluxes, shows significant impacts from the growth of multi-energy anisotropic modes, and breaks the symmetry of the heavy-flavor sector by raising the average energy of heavy-flavor antineutrinos above that of heavy-flavor neutrinos. However, the CFI remains subdominant to the FFI in most of the disk. In our global quantum-kinetic simulations with an attenuated Hamiltonian, flavor coherence develops primarily in the polar regions. Because the attenuation causes advection to outpace the growth of the instabilities, coherence and flavor conversion remain artificially suppressed within the disk. These results emphasize the resolution and scaling requirements for future global simulations that capture instability growth, saturation, and advection simultaneously.

    ↳ astro-ph.HEhep-ph5 citations
28. 28*

    Massive modes on magnetized blow-up manifold of $T^2/{\mathbb{Z}}_N$

    Tatsuo Kobayashi🇯🇵 · Hajime Otsuka🇯🇵 · Hikaru Uchida🇯🇵

    We study massive modes on a magnetized blow-up manifold of $T^2/{\mathbb{Z}}_N$. The blow-up manifold can be constructed by appropriately replacing orbifold singular points with a part of $S^2$. To ensure a smooth connection between the massive modes on magnetized $T^2/{\mathbb{Z}}_N$ orbifold and those on magnetized $S^2$, it is required that not only the total magnetic flux as well as the total curvature but also the effective magnetic flux on the connected line remain invariant under the blow-up procedure. Furthermore, we find that the number of the localized modes at each orbifold singular point increases by one for each unit increment of the mass level.

    ↳ hep-thhep-ph0 citations
29. 29*

    Quantum simulation of baryon scattering in SU(2) lattice gauge theory

    João Barata🇨🇭 · Juan Hormaza🇨🇴 · Zhong-Bo Kang🇺🇸 · Wenyang Qian🇪🇸

    We present a first real-time study of hadronic scattering in a $(1+1)$-dimensional SU(2) lattice gauge theory with fundamental fermions using tensor-network techniques. Working in the gaugeless Hamiltonian formulation, we investigate scattering processes across sectors of fixed global baryon number $B=0,1,2$, corresponding respectively to meson--meson, meson--baryon, and baryon--baryon collisions. At strong coupling, the $B=0$ and $B=2$ channels exhibit predominantly elastic dynamics closely resembling the U(1) Schwinger model. The mixed $B=1$ sector displays qualitatively new behavior: meson and baryon wavepackets become entangled during the collision, with the slower state becoming spatially delocalized while the faster one propagates ballistically. We characterize these processes through local observables, entanglement entropy, and the information lattice.

    ↳ hep-lathep-phnucl-thquant-phJ.Subatomic Part.Cosmol.(2026)·0 citations
30. 30*

    Emergence of Non-Markovian Classical-Quantum Dynamics from Decoherence

    Shogo Tomizuka🇯🇵 · Hiroki Takeda🇯🇵

    The quantum nature of gravity remains experimentally unverified, despite recent proposals to probe it using tabletop experiments such as gravity-mediated entanglement schemes. In parallel, consistent formulations of classical--quantum dynamics have been developed as alternative descriptions of gravity, in which quantum matter interacts with a classical mediator assumed to be fundamentally classical. In this work, we show that classical--quantum dynamics arise generically as an effective description of fully quantum systems under decoherence, providing a bridge between fully quantum and classical--quantum dynamics. We derive the reduced dynamics, which are generically non-Markovian, using an explicit hidden model in which the mediator is coupled to unobserved environmental degrees of freedom. We identify a concrete criterion for when a classical--quantum interpretation is valid: the semi-Wigner operator associated with the mediator sector must remain positive semidefinite, which can be expressed as a positivity condition on nonlocal kernels governing the evolution. In the short-memory limit, the reduced evolution reproduces Markovian classical--quantum dynamics of Oppenheim and collaborators. Our results imply that a classical mediator can arise effectively from decohered quantum dynamics, so that experimental agreement with classical-quantum models does not uniquely determine whether the mediator is fundamentally classical.

    ↳ quant-phgr-qchep-phhep-th1 citation
31. 31*

    $B\to D^{\ast }\ell \nu$ from LQCD: is there light at the end of the tunnel?

    Alejandro Vaquero🇪🇸

    Lattice QCD (LQCD) calculations play a key role in the establishment of flavor anomalies. One of the most recent advancements in LQCD to this end has been the publication of several calculations of the $B\to D^{\ast }\ell \nu$ form factors, but despite all the anticipation, the LQCD results have been unable to give a final answer to the questions it was destined to answer. In this work I briefly review what is the current status of heavy-to-heavy and heavy-to-light semileptonic decays calculations in LQCD, and what we can expect for the near and not-so-near future.

    ↳ hep-lathep-ph0 citations
32. 32*

    Revisiting the sphaleron and axion production rates in QCD at high temperatures

    Sayak Guin🇮🇳 · Sayantan Sharma🇮🇳

    We report our new lattice results for the sphaleron rate calculated within a thermal effective field theory of soft SU(N) gluons whose momenta are below the magnetic scale, where $N=2,3$, for a wide range of temperatures spanning from $0.6$ to $10^{15}$ GeV at sufficiently large volumes. Comparing these results with sphaleron rates in a nonthermal SU(N) plasma where the infrared gluons are overoccupied, we estimate the typical thermalization time for these ultrasoft gluons during the early stages of reheating after inflation. We also calculate the thermal production rate of relativistic axions due to these non-perturbatively interacting soft gluons which shows a significant deviation from its perturbative estimate even at the electroweak scale.

    ↳ hep-latastro-ph.COhep-phhep-thPRD(2026)·4 citations
33. 33*

    Primordial magnetic fields in the light of upcoming post-EoR Lyman-$\alpha$ and 21-cm observations

    Arko Bhaumik🇮🇳 · Sourav Pal🇮🇳 · Supratik Pal

    The Lorentz force exerted by a primordial magnetic field (PMF) on the coupled baryon-dark matter system may enhance total matter power at small scales after recombination. In the post-reionization (post-EoR) era, a weakly scale-dependent PMF of sub-nG strength is thus expected to influence the Lyman-$\alpha$ (Ly$\alpha$) power spectrum, the 21 cm power spectrum, and the Ly$\alpha$-21 cm cross-spectrum at scales $k\gtrsim 1h/\text{Mpc}$. We investigate the prospects of constraining the PMF sector via these three cosmological observables, by employing SNR estimation and Fisher forecast on the PMF amplitude $B_0$ and spectral index $n_{\mathrm{B}}$, for a next-generation DESI-like spectroscopic survey and two upcoming 21 cm facilities, namely SKA1-Mid and PUMA. Our results indicate the possibility of constraining both PMF parameters with $\lesssim 10\%$ relative errors through the uncontaminated 21 cm auto-spectrum as well as the Ly$\alpha$-21 cm cross-spectrum probed with the DESI-like+SKA1-Mid combination. Indicatively, the Ly$\alpha$-21 cm cross-correlation via DESI-like+SKA1-Mid is predicted to constrain a fiducial scenario $B_0=0.8$ nG and $n_{\mathrm{B}}=-2.9$ with $1\sigma$ errors $\Delta B_0\approx 0.07$ nG and $\Delta n_{\mathrm{B}}\approx 0.02$. The DESI-like+PUMA setup is predicted to fare relatively worse due to its restriction to larger scales, resulting in comparatively one order of magnitude relaxed error bounds for similar fiducials. Since the Ly$\alpha$-21 cm cross-signal is expected to be largely insensitive to foreground contamination (unlike the 21 cm auto-spectrum), it may serve as an optimal foreground-immune post-EoR probe to constrain a weakly scale-dependent sub-nG PMF via future DESI-like+SKA1-Mid observations.

    ↳ astro-ph.COastro-ph.IMhep-ph3 citations
34. 34*

    Theoretical and Observational Bounds on Dynamical Chern-Simons Gravity as an Effective Field Theory

    Alexander Cassem🇺🇸 · Mark P. Hertzberg🇺🇸

    Gravitational effective theories are essential for characterizing the space of deviations from General Relativity (GR). Testing these theories against fundamental principles, such as causality and unitarity, can yield constraints on the corresponding parameters. In this paper, we perform such an analysis on the very interesting dynamical Chern-Simons (dCS) gravity. This is a parity violating correction to GR wherein a new scalar field couples to the Pontryagin density ${}^{\ast }RR$. It has generated significant interest, including possible new gravitational wave shapes for LIGO/Virgo and new phenomena from cosmic inflation. In this work, we begin by deriving the dispersion relation and wave packet speed on top of a gravitational wave background in dCS gravity. This alters the corresponding Shapiro time delay (which we compute to second order), potentially giving superluminality. Causality then demands a bound on the dCS coupling constant, which we find to be moderately sharper than, but compatible with, standard estimates. We then examine a UV completion in the form of a set of $N$ fermions with a (pseudo) Yukawa coupling. By imposing perturbativity and a gravitational species bound, we find that the dCS coupling constant is constrained significantly more, depending on the choice of scale of the species bound. We also identify higher order operators generated from the UV completion. Overall, we find that any dCS corrections to gravitational dynamics should likely be very small on macroscopic systems of observational interest, such as in late-time merging black holes.

    ↳ hep-thastro-ph.COgr-qchep-ph2 citations
35. 35*

    Quantum Simulation of Collective Neutrino Oscillations using Dicke States

    Katarina Bleau🇩🇪 · Nikolina Ilic🇨🇦 · Joachim Kopp🇩🇪 · Ushak Rahaman🇨🇦 · Xin Yue Yu🇨🇦

    In dense neutrino gases, which exist for instance in supernovae, the flavour states of different neutrinos may become entangled with one another. The theoretical description of such systems may therefore call for simulations on a quantum computer. Existing quantum simulations of simple toy systems are not optimal in the sense that they do not fully exploit the symmetries of the system. Here, we propose a new class of qubit-efficient algorithms based on Dicke states and the $su(2)$ spin algebra. We demonstrate the excellent performance of these algorithms both on classical and on quantum hardware.

    ↳ quant-phastro-ph.HEhep-ph3 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.