Tue·Apr 14, 2026Tuesday·April 14, 2026

1. 01*

   Visible Neutrino Decay As An Open Quantum System

   Joachim Kopp🇩🇪 · George A. Parker (JGU Mainz)🇩🇪

   Decays of heavier neutrino mass eigenstates into lighter ones, while very slow in the Standard Model, can be significantly enhanced in scenarios with more than three neutrino flavours, or in models with new ultra-light particles such as Majorons. A full theoretical description is challenging due to the intricate interplay between oscillations and decay, interference between different decay channels, and the possibility of multi-step decay cascades. In this paper, we develop a fully general description of arbitrarily complex systems of oscillating and decaying neutrinos using methods from the theory of open quantum systems. Notably, we demonstrate how such systems can be implemented using the Lindblad master equation, the Liouvillian superoperator, as well as Kraus operators. The last two methods eschew the need for solving a differential equation, thereby showing superior numerical performance.

   hep-phhep-exquant-ph0 citations
2. 02*

   Feynman integral reduction by covariant differentiation

   Gero von Gersdorff🇧🇷 · Vinicius Lessa🇧🇷

   We show how a large class of Feynman integrals can be efficiently reduced to master integrals by suitable covariant differentiation on the vector space dual to the one spanned by the master integrals. The connections needed in the covariant derivatives have to be built only once for a given topology and then apply to any configuration of internal propagator masses. We implement our algorithm in the Mathematica code Method for Reduction of Loop Integrals (MERLIN).

   hep-phhep-th3 citations
3. 03*

   A Consistent Treatment of Final-State Interactions in NuWro Quasielastic Channel

   Rwik Dharmapal Banerjee🇵🇱

   In this proceeding, I present a modified treatment of final-state interactions (FSI) in quasielastic (QE) lepton-nucleus scattering within the spectra function (SF) framework of the NuWro Monte Carlo generator. Our approach establishes a consistent correspondence between inclusive cross-section calculations and exclusive descriptions of hadron-propagation by combining a convolution-based formalism at the cross-section level with an event-level implementation in which interactions are classified as transparent or non-transparent within the NuWro intranuclear cascade. This unified framework enables realization of FSI effects across inclusive observables and exclusive final states. We demonstrate the impact of this implementation by comparing predictions to both inclusive electron-scattering data and exclusive MicroBooNE measurements of CCQE-dominated observable, showing that the inclusion of FSI leads to a significant improvement in agreement with the data.

   hep-phhep-thnucl-th0 citations
4. 04*

   Induced Multi-phase Inflation with Reheating: Leptogenesis and Dark Matter Production in Metric versus Palatini

   Nilay Bostan🇹🇷 · Rafid H. Dejrah🇹🇷 · Anish Ghoshal🇬🇧 · Zygmunt Lalak🇵🇱

   We study non-minimally coupled scalar-induced multi-phase inflation in metric and Palatini gravity, considering linear, Brans-Dicke-like, and Higgs-like sectors. The scalar spectral index lies in the range \( n_s \simeq 0.93 \ \text{--} \ 0.98 \), consistent with \textit{Planck} and combined \textit{Planck}+ACT data. The tensor-to-scalar ratio can reach \( r \sim 0.03 \) in metric, whereas Palatini models generically predict \( r \lesssim 10^{-5} \). In the Palatini case, field excursions remain sub-Planckian, and the perturbative unitarity cutoff is raised. Reheating proceeds via perturbative inflaton decays into Higgs bosons and fermionic dark matter (DM) through the portal coupling \( \lambda_{12} \) and Yukawa coupling \( y_\chi \). Radiative stability of the inflationary plateau constrains the couplings to \( y_\chi, \lambda_{12} \sim 10^{-7} \ \text{--} \ 10^{-3} \), implying \( 4\,\mathrm{MeV} \lesssim T_{\rm rh} \lesssim 10^{15}\,\mathrm{GeV} \). Palatini realizations require smaller couplings and thus a narrower reheating window. Non-thermal DM production $\chi$ from inflaton decays is viable for DM mass \( m_\chi \sim \mathrm{keV} \ \text{--} \ \mathrm{PeV} \) with \( y_\chi \lesssim 10^{-6} \) over large parameter regions. We estimate the inflaton-right-handed neutrino (RHN) Yukawa coupling \( y_N \) required for successful baryogenesis via non-thermal leptogenesis within a Type-I seesaw framework, for the lightest RHN mass \( M_{N_1} \sim 10^{9} \ \text{--} \ 10^{14}\,\mathrm{GeV} \), provided \( M_{N_1} > T_{\rm max} \), where \( T_{\rm max} \) follows from radiatively consistent reheating. In Palatini scenarios, the lower maximal temperature and tighter stability bounds further restrict the leptogenesis parameter space.

   hep-phastro-ph.COgr-qchep-th2 citations
5. 05*

   Toward selective quantum advantage in hadronic tomography:explicit cases from Compton form factors, GPDs, TMDs, and GTMDs

   I. P. Fernando🇺🇸 · D. Keller🇺🇸

   We recast the case for quantum advantage in hadronic physics as an observable-by-observable question rather than a blanket claim about Quantum Chromo-Dynamics (QCD). Focusing on hadronic tomography, we analyze why Compton form factors (CFF), generalized parton distributions (GPDs), Transverse Momentum-dependent Distributions (TMDs), and Generalized Transverse Momentum-dependent Distributions (GTMDs) are natural quantum targets: they are defined by light-front, off-forward, or real-time correlation functions whose extraction from Euclidean calculations or sparse experimental data is often an ill-posed inverse problem. We separate three notions of advantage -- algorithmic, computational, and representational -- and connect each to explicit formal objects. At the algorithmic level, Hamiltonian simulation, linear-response algorithms, and amplitude-estimation primitives motivate gains for real-time and sign-problematic observables. At the computational level, direct quantum evaluation of matrix elements and correlators becomes plausible for PDFs, GPDs, timelike response, and high-energy evolution. At the inference level, recent Quantum Deep Neural Network (QDNN) studies of CFF extraction indicate improved performance in noisy and sparse regimes and motivate hybrid fits in which a quantum simulator supplies a physics prior while a classical network models detector and nuisance effects. We discuss why real-device execution is scientifically necessary, summarize current hardware milestones, and propose benchmark criteria for credible claims of quantum advantage in hadronic tomography.

   hep-ph2 citations
6. 06*

   Chiral Condensation and Chiral Phase Diagram under Combined Rotation and Chemical Potential in Holographic QCD

   D.-Y. Long🇨🇳 · S.-Q. Feng🇨🇳

   We investigate the combined effects of rotation and finite quark chemical potential on inhomogeneous chiral condensation and the chiral phase diagram within the soft-wall holographic QCD model. Using the five-dimensional AdS-RN metric, we study the spatial profile of the chiral condensate and the resulting $T-\Omega$ phase diagram under Neumann and Dirichlet boundary conditions. Increasing $\Omega$ induces strong spatial inhomogeneity: the condensate is suppressed more strongly near the edge than at the center, and vanishes at the boundary when $\Omega$ exceeds a critical value. The chemical potential $\mu$ acts as a global suppression factor, reducing the condensate magnitude without altering the spatial pattern. The $T-\Omega$ phase diagrams are investigated for different chemical potentials. For the case $\mu$ = 0, they are also studied at different distances from the rotation axis. It is found that both $\Omega$ and $\mu$ lower the chiral phase transition temperature, and their suppression effects are additive. In a rotating system, the critical temperature becomes position-dependent, decreasing with increasing distance from the rotation axis. These findings reveal a rich, spatially dependent phase structure in rotating QCD matter, relevant for non-central heavy-ion collisions.

   hep-phEPJC(2026)·0 citations
7. 07*

   William A. Bardeen -- A Brief Biography

   Christopher T. Hill🇺🇸

   William Allan Bardeen (September 15, 1941 $-$ November 18, 2025) was an American theoretical physicist who worked at the Fermi National Accelerator Laboratory. He is renowned for his foundational work on the chiral anomaly, the Adler-Bardeen theorem, the non-Abelian anomaly and gravitational anomalies. He was instrumental in the development of quantum chromodynamics and its applications, such as semileptonic decays and the ${\Lambda }_{\overline{MS}}$ scheme frequently used in perturbative analysis of high energy processes involving strong interactions. Bardeen also played a major role in developing a theory of dynamical breaking of electroweak symmetry via top quark condensates, leading to one of the first composite Brout-Englert-Higgs boson models. His work on the chiral symmetry dynamics of heavy-light quark bound states correctly predicted abnormally long-lived resonances which are chiral symmetry partners of the ground state.

   hep-phhep-exhep-lathep-thNPB(2026)·0 citations
8. 08*

   DREAMuS: Dark matter REsearch with Advanced Muon Source

   Xiang Chen🇨🇳 · Zejia Lu🇨🇳 · Liangwen Chen🇨🇳 · Jun Gao🇨🇳 · Shao-Feng Ge🇨🇳 · Zhanxu Hao🇨🇳 · Yang Hu🇨🇳 · Bingzhi Li🇨🇳 · Cen Mo🇨🇳 · Zhiyu Sun🇨🇳 · Huayang Wang🇨🇳 · Chonghao Wu🇨🇳 and 4 other authors

   We propose DREAMuS, a fixed-target experiment at the High Intensity Heavy-Ion Accelerator Facility (HIAF), to search for muon-philic dark matter mediated by light flavor-violating bosons. DREAMuS is designed to probe the parameter space of a muon-philic dark matter (DM) mediated by a light flavor-violating boson, specifically a vector $Z^{\prime }$ (or a scalar $\varphi$) which is produced in muon-nucleus interactions and decays into dark matter particles with a distinctive detector signature. Precision tracking and time-of-flight measurements are used to suppress the Standard Model backgrounds. We find that DREAMuS can achieve competitive sensitivity in the GeV-scale muon-philic dark matter parameter space, reaching sensitivity to couplings at the $10^{-4}$, especially in the few-hundred-MeV region.In addition to a ${\mu }^{-}$ run, we highlight the potential of a complementary ${\mu }^{+}$ beam option, further improving sensitivity to dark matter below 200 $\mathrm{MeV}$ by an order of magnitude.

   hep-phhep-ex2 citations
9. 09*

   Pion Weak Decay in a Magnetic Field

   Prabal Adhikari🇺🇸 · Brian C. Tiburzi🇺🇸

   Pion decay width in a uniform magnetic background, constructed within chiral perturbation theory, is compared with lattice QCD for which results are available in the muon channel. While the results are consistent for large magnetic fields, the discrepancy observed for weak magnetic fields is largely due to differences in the pion decay constants.

   hep-phhep-latActa Phys.Polon.Supp.(2026)·0 citations
10. 10*

    Resonance $X(6600)$

    S. S. Agaev🇦🇿 · K. Azizi🇮🇷 · H. Sundu🇹🇷

    The resonance $X(6600)$ is explored as the all-charm tetraquark structure with spin-parities $J^{\mathrm{PC}}=2^{++}$. It is considered in the diquark-antidiquark picture and modeled as a tensor state $X$ composed of the axial-vector diquark $cC{\gamma }_{\mu }c$ and antidiquark $\overline{c}$ with $C$ being the charge conjugation matrix. The mass and decay width of $X$ are evaluated in the framework of QCD sum rule (SR) methods. The two-point SR approach is applied to find its spectroscopic parameters, while three-point SRs used to calculate partial widths of different decay channels of $X$. We study its leading decays $X\to J/\psi J/\psi$, $X\to {\eta }_c{\eta }_c$ and ${\chi }_{c1}(1P){\eta }_c$ in which all four $c$-quarks constitute final-state mesons. We consider also the subleading channels $X\to D_{(s)}^{(\ast )+}{D}_{(s)}^{(\ast )-}$ and generated by annihilation of $\overline{c}c$ quarks in the tetraquark. Comparison of the mass $m=(6609\pm 50)\mathrm{MeV}$ and width $\Gamma [X]=(165\pm 23)\mathrm{MeV}$ of the tensor diquark-antidiquark state $X$ with experimental data allows us to interpret it as an essential component of the resonance $X(6600)$. We also provide a lower limit for the mass of the first radial excitation of $X$.

    hep-phhep-exhep-latNPB(2026)·3 citations
11. 11*

    Novel analysis for the energy-energy correlation in electron-positron annihilation in the perturbative domain

    Zhu-Yu Ren🇨🇳 · Sheng-Quan Wang🇨🇳 · Jian-Ming Shen🇨🇳 · Xing-Gang Wu🇨🇳 · Leonardo Di Giustino🇮🇹 · Philip G. Ratcliffe🇮🇹 · Stanley J. Brodsky🇺🇸

    The energy-energy correlation (EEC) in electron-positron annihilation plays a crucial role in precision tests of quantum chromodynamics (QCD) and measurements of the QCD coupling constant. In this paper, we provide a novel analysis for the EEC by using the Principle of Maximum Conformality (PMC), a systematic method for eliminating renormalization scheme-and-scale ambiguities. The PMC scales are determined by resumming the non-conformal $\beta$-terms that govern the behavior of the QCD running coupling via the renormalization group equation, and reflect the virtuality of the propagating gluons in QCD. It is noteworthy that the resulting PMC scale varies dynamically with the EEC's angular distribution, reflecting the expected scale's physical behavior. Moreover, due to the reabsorption of all $\beta$-terms, including also those related to the divergent renormalon terms such as $n!{\beta }_0^n{\alpha }_s^n$, in the pQCD series, the behavior of the QCD perturbative coefficient using PMC, differs entirely from that of the conventional coefficient. Consequently, the PMC predicted EEC distribution agrees well with the experimental data in the perturbative domain.

    hep-phhep-ex1 citation
12. 12*

    Accessing gluon GTMD $F_{1,4}^g$ via the $⟨\sin (2\varphi )⟩$ azimuthal asymmetry of exclusive ${\pi }^0$ production in $ep$ collisions

    Chentao Tan🇨🇳 · Zhun Lu🇨🇳

    The longitudinal single-target spin asymmetry in exclusive ${\pi }^0$ production in $ep$ collisions is a sensitive probe of the imaginary part of the gluon generalized transverse momentum dependent distribution $F_{1,4}^g$. It appears as a characteristic $\sin (2\varphi )$ azimuthal correlation between the transverse momenta of the scattered electron and the recoil proton, generated by Coulomb-nuclear interference; consequently, the Primakoff process should be included. We compute the relevant gluon distributions in a light-front spectator model of the proton that explicitly incorporates gluonic degrees of freedom. This work presents the first model calculation of the imaginary part of $F_{1,4}^g$ and delivers predictions for the resulting asymmetries in kinematics relevant to the planned Electron-Ion Colliders (EIC and EicC), providing theoretical predictions for upcoming measurements.

    hep-phEPJC(2026)·0 citations
13. 13*

    Heavy-quark transport across the QCD crossover driven by a lattice-constrained in-medium potential

    Wu Wang🇨🇳 · Yuqi Luo🇨🇳 · Fei Sun🇨🇳 · Sa Wang🇨🇳 · Jungang Deng🇨🇳 · Wei Xie🇨🇳 · Shuang Li🇨🇳 · Kejun Wu🇨🇳

    We present a self-consistent framework for heavy-quark transport in the quark-gluon plasma across the QCD crossover region. By synthesizing perturbative and nonperturbative interactions into a unified interaction kernel, we circumvent the traditional reliance on arbitrary soft-hard momentum separation scales. The interaction is governed by an in-medium effective potential, incorporating short-range Yukawa screening and long-range confining string contributions, both rigorously constrained by the latest lattice QCD data. Our results reveal that the nonperturbative string tension is indispensable for capturing the extreme opacity of the medium near the critical temperature $T_c$. Specifically, our model predicts a spatial diffusion coefficient of $2\pi T{D}_s\approx 0.5\sim 1.7$, demonstrating a striking quantitative agreement with the recent lattice QCD extractions. Ultimately, our results provide a robust dynamical interpretation of the strong heavy-quark coupling near the QCD crossover and offer a unified framework for describing heavy-flavor transport in hot and dense QCD matter.

    hep-phPRD(2026)·0 citations
14. 14*

    Study of doubly heavy baryon lifetimes

    Hai-Yang Cheng🇹🇼 · Chia-Wei Liu🇨🇳

    We study the lifetimes and inclusive semileptonic decay widths of doubly heavy baryons within the framework of heavy quark expansion. Our analysis includes next-to-leading-order corrections to the dimension-3, -5, and -6 operators, together with the leading dimension-7 contributions, while the nonperturbative matrix elements are evaluated in a bag model with translationally improved baryon wave functions. We obtain $({\tau }_{{\Xi }_{cc}^{++}},{\tau }_{{\Xi }_{cc}^{+}},{\tau }_{{\Omega }_{cc}^{+}})=(2.67_{-0.94}^{+0.95},0.47_{-0.08}^{+0.09},1.79_{-0.62}^{+0.64})\times 10^{-13}\mathrm{s}$ and $({\tau }_{{\Xi }_{bb}^0},{\tau }_{{\Xi }_{bb}^{-}},{\tau }_{{\Omega }_{bb}^{-}})=(0.75_{-0.11}^{+0.13},0.92_{-0.15}^{+0.15},0.93_{-0.15}^{+0.15})\times 10^{-12}\mathrm{s}$. The lifetime hierarchy patterns are found to be $\tau ({\Xi }_{cc}^{++})>\tau ({\Omega }_{cc}^{+})>\tau ({\Xi }_{cc}^{+})$ and $\tau ({\Omega }_{bb}^{-})\sim \tau ({\Xi }_{bb}^{-})>\tau ({\Xi }_{bb}^0)$ for doubly charmed and bottom baryons, respectively. The $W$-exchange contribution plays a crucial role in generating the large lifetime splitting in the doubly charmed sector and remains phenomenologically important for doubly bottom baryons. In particular, for ${\Xi }_{cc}^{+}$ the dominant dimension-6 spectator effect, namely $W$-exchange, surpasses the nominally leading term. The same spectator operator is realized as destructive Pauli interference in $D^{+}$, owing to the $d$ versus $\bar{d}$ spectator. Although the ${\Xi }_{cc}^{+}$ case does not lead to the negative decay width encountered for $D^{+}$, the absolute value of $\tau ({\Xi }_{cc}^{+})$ should nevertheless be regarded as only indicative. In addition to the total lifetimes, we calculate the separate nonleptonic and semileptonic contributions, which allow us to trace the pattern of spectator effects in each baryon channel.

    hep-phhep-exJHEP(2026)·4 citations
15. 15*

    Study of ${\chi }_{cJ}\to \eta \eta {\eta }^{\prime }$ via intermediate charmed meson loop mechanisms and its implications for non-observation of ${\eta }_1(1855)$ in ${\chi }_{cJ}$ decays

    Xin-Ru Wang🇨🇳 · Shu-Qi Wang🇨🇳 · Shi-Dong Liu🇨🇳 · Qi Wu🇨🇳 · Gang Li🇨🇳 · Ju-Jun Xie🇨🇳

    Recently, the BESIII Collaboration reported the first observation of the decays ${\chi }_{cJ}\to \eta \eta {\eta }^{\prime }$ in order to search for the $1^{-+}$ exotic state ${\eta }_1(1855)$. A partial wave analysis of the $\eta {\eta }^{\prime }$ invariant mass spectrum shows no significant signal for the ${\eta }_1(1855)$. In this work, we, using an effective Lagrangian approach, investigate the processes ${\chi }_{cJ}\to \eta \eta {\eta }^{\prime }$ via the box and triangle loops involving charmed mesons and the scalar meson $f_0(1500)$. Our calculations reproduce well the experimental branching fractions of ${\chi }_{cJ}\to \eta \eta {\eta }^{\prime }$. Furthermore, we present the predictions of the relevant invariant mass spectra of $\eta {\eta }^{\prime }$ and $\eta \eta$ produced in the ${\chi }_{c1}$ decay, which seem overall consistent with the BESIII measurements. In the present model, the decay ${\chi }_{c1}\to \eta \eta {\eta }^{\prime }$ is dominated by the triangle and box loop contributions. The consistency between our theoretical results and the BESIII measurements sheds light on the underlying decay mechanism of the ${\chi }_{cJ}$ decaying into light mesons and might be helpful to understand the absence of the ${\eta }_1(1855)$ signal in the decay channels ${\chi }_{cJ}\to \eta \eta {\eta }^{\prime }$.

    hep-phhep-exEPJC(2026)·0 citations
16. 16*

    Resonant Leptogenesis in a Two-Triplet Type-II Seesaw: A Dynamical Origin of Suppressed Lepton Flavor Violation

    Avinanda Chaudhuri🇮🇳

    We investigate resonant leptogenesis in a two-triplet Type-II seesaw framework and demonstrate a coherent and predictive connection between neutrino mass generation, baryogenesis, and charge lepton flavor violation (LFV). In the presence of quasi-degenerate scalar triplets, self-energy effects induce a resonant enhancement of the CP asymmetry, enabling successful baryogenesis at the TeV scale. We construct Yukawa couplings consistent with neutrino oscillation data and perform a comprehensive numerical analysis by solving the Boltzmann equations across a wide parameter space. We find that viable solutions arise only within a restricted region characterized by near-resonant mass splittings and moderate-to-strong washout. In this regime, successful leptogenesis is achieved through resonant enhancement, which compensates for suppressed Yukawa couplings. A key prediction of the framework is that the allowed parameter space dynamically favors small Yukawa couplings, leading to strongly suppressed LFV rates. The near-absence of observable LFV signals therefore emerges as a direct consequence of the dynamics responsible for baryogenesis. Our results highlight a distinctive feature of the two-triplet Type-II scenario: the simultaneous realization of resonant enhancement and LFV suppression within a unified and testable framework.

    hep-ph2 citations
17. 17*

    Radiatively Corrected Hybrid Inflation: Parameter Scans and Machine Learning with ACT and Future CMB Experiments

    Waqas Ahmed🇨🇳 · Saleh O. Allehabi🇸🇦 · Mansoor Ur Rehman🇸🇦

    We investigate a realistic non-supersymmetric hybrid inflation model incorporating right-handed neutrinos and assess its viability in light of recent cosmological observations. At tree level, the inflaton potential yields a blue-tilted scalar spectrum, which is disfavored by current data from Planck and ACT that instead support a red tilt. We show that including one-loop quantum corrections, arising from generic couplings required for reheating, significantly modifies the potential, flattening it at large field values. This leads to a red-tilted spectral index ($n_s<1$) and a suppressed tensor-to-scalar ratio $r$, both consistent with observational constraints. To ensure theoretical control, we focus on sub-Planckian field values, where the effective field theory description remains valid. The coupling of the inflaton to right-handed neutrinos naturally facilitates efficient reheating and enables the generation of the baryon asymmetry via non-thermal leptogenesis. We further explore the model's parameter space using a multi-output random forest classifier, achieving prediction accuracies in the range of $87.5\%$ to $98.9\%$. Our analysis shows that approximately $15\%$ of the parameter space satisfies at least one current experimental constraint, underscoring the essential role of quantum corrections in reconciling particle physics models with precision cosmology, and highlighting the effectiveness of machine learning techniques in probing complex theoretical frameworks.

    hep-phastro-ph.COPRD(2026)·2 citations
18. 18*

    Extraction of Pion Unpolarized Quark Generalized Parton Distribution from Charge Form Factors

    Satyajit Puhan🇹🇼 · Shubham Sharma🇷🇺 · Narinder Kumar🇮🇳 · Harleen Dahiya🇮🇳

    Based on a global fit to experimental measurements of the pion electromagnetic form factor and parton distribution functions (PDFs), we report a data-driven determination of the unpolarized quark generalized parton distributions (GPDs) for the case of pion in the zero-skewness limit ($\xi =0$). The form factor is parameterized using a flexible functional form constrained by data and embedded into a GPD framework constructed from collinear PDFs and a profile function encoding transverse dynamics. This approach provides a unified description of the pion's electromagnetic structure and its spatial parton distributions. We present the extracted pion GPDs and their impact-parameter-space interpretations, offering new insights into the internal structure of the lightest QCD bound state and providing essential input for future electron-ion collider studies via the Sullivan process, as well as for the exclusive ${\pi }^{+}$ electroproduction at the 12~GeV Jefferson Lab program, pion-induced exclusive measurements at COMPASS, proposed pion-beam experiments at AMBER, and phenomenological and lattice investigations of the structure of the meson.

    hep-ph2 citations
19. 19*

    Bounds from D/H on baryogenesis models

    Aleksandr Azatov🇮🇹 · Bruno Missoni🇮🇹

    We review the constraints on baryon inhomogeneities derived from measurements of the deuterium abundance, $D/H$, and apply them to a range of baryogenesis models. In particular, we derive bounds on electroweak baryogenesis as well as on more exotic scenarios. Our results show that, across most of the relevant parameter space, electroweak baryogenesis remains largely unconstrained by current and foreseeable $D/H$ measurements. By contrast, the constraints on alternative scenarios are significantly stronger and can exclude regions of parameter space that would otherwise remain viable.

    hep-ph3 citations
20. 20*

    Machine learning study on single production of a singlet vectorlike lepton at the Large Hadron Collider

    Yiheng Cui🇨🇳 · Shiyu Wang🇨🇳 · Zhao-Huan Yu🇨🇳 · Hong-Hao Zhang🇨🇳

    Vectorlike leptons are nonchiral, colorless fermions from new physics beyond the Standard Model, appearing in many theoretical extensions. We investigate the prospect for detecting the single production of a singlet vectorlike lepton that mixes with the $\tau$ lepton at the Large Hadron Collider. The corresponding final states are classified as the three- and four-lepton search channels. The machine learning algorithm XGBoost is employed to enhance signal-background discrimination. Our analysis indicates that, at $\sqrt{s}=14\mathrm{TeV}$ with an integrated luminosity of $3000{\mathrm{fb}}^{-1}$ under the assumption of negligible systematic uncertainties, the expected $2\sigma$ exclusion limits in the three- and four-lepton channels can reach vectorlike lepton masses up to $500$ and $405\mathrm{GeV}$ in the parameter region allowed by the electroweak oblique parameter constraint, respectively. These findings demonstrate that machine learning techniques can substantially improve the sensitivity of collider searches for vectorlike leptons.

    hep-phPRD(2026)·1 citation
21. 21*

    Dirac one-loop seesaw in a non-invertible fusion rule

    Hiroshi Okada🇨🇳 · Labh Singh🇮🇳

    We propose a radiative Dirac neutrino mass model stabilized by a non-invertible fusion rule originating from a $Z_3\times Z_3^{\prime }$ gauging. The imposed symmetry forbids tree-level Yukawa couplings and ensures that neutrino masses are generated only at the one-loop level through the exchange of exotic fermions and inert scalars. This minimal framework simultaneously accommodates neutrino masses and mixings consistent with current oscillation data, while providing a viable dark matter candidate. We analyze lepton flavor violating processes and lepton anomalous magnetic moments, finding that all contributions remain well below present experimental bounds. In the dark matter sector, the bosonic singlet emerges as a promising candidate with relic density compatible with cosmological observations, whereas the fermionic option is strongly disfavored due to suppressed annihilation cross sections. Our study demonstrates that non-invertible fusion rules can serve as a powerful organizing principle for constructing minimal and phenomenologically consistent extensions of the Standard Model, linking neutrino physics and dark matter within a unified radiative framework.

    hep-phhep-th1 citation
22. 22*

    Searching for apparent baryon number violation in ${\Lambda }_c^{+}$ decays at the Super Tau-Charm Facility

    Zeren Simon Wang🇨🇳 · Xin-Ru Tang🇨🇳 · Yu Zhang🇨🇳 · Yu Zhang🇨🇳 · Xiaorong Zhou🇨🇳

    Observation of baryon number violation (BNV) in laboratory experiments would constitute unambiguous evidence for physics beyond the Standard Model. We propose dedicated searches for \textit{apparent} BNV in charm-baryon decays, ${\Lambda }_c^{+}\to M^{+}+$ missing energy ($M=\pi ,K$) where the missing energy stems from a resonance. These channels have not been explored experimentally so far, despite the relatively clean environment potentially provided by near ${\Lambda }_c^{+}{\overline{\Lambda }}_c^{-}$ threshold production at $e^{+}{e}^{-}$ colliders. Performing state-of-the-art Monte Carlo simulations for the proposed Super Tau-Charm Facility (STCF), we evaluate the signal efficiencies and derive projected model-independent sensitivities under the assumption of negligible background. We further interpret these sensitivities within two theoretical frameworks: a sterile-neutrino-extended low-energy effective field theory ($\nu$LEFT) and R-parity-violating (RPV) supersymmetry. With an integrated luminosity of 1 ab${}^{-1}$, STCF can probe new-physics scales of several TeV in the $\nu$LEFT description and constrain the RPV model parameter ${\lambda }_{212}^{\prime \prime }/m_{\tilde{q}}^2$ down to about $0.1{\mathrm{TeV}}^{-2}$. Our results demonstrate that STCF provides a highly competitive opportunity for probing BNV interactions in rare charm-baryon decays.

    hep-phhep-exPRD(2026)·0 citations
23. 23*

    Renormalization of three-quark operators with up to two derivatives at three loops

    B. A. Kniehl🇩🇪 · O. L. Veretin🇩🇪

    We study in QCD the $\overline{\mathrm{MS}}$ renormalization of three-quark operators with up to two covariant derivatives, which are related to $N=0,1,2$ Mellin moments of baryonic light-cone distributions amplitudes. Apart from general three-quark operators, we also consider those corresponding to spin 3/2 and 1/2 states. We present in analytic form the renormalization constants and anomalous dimensions of these operators through three loops, confirming previous two- and three-loop results for $N=0$. Furthermore, we evaluate through two loops their amputated four-point Green's functions with RI${}^{\prime }$/MOM four-momentum assignment, which are required for the matching of lattice results with perturbative calculations. We work in linear covariant gauge and find the anomalous dimensions to be gauge independent as expected.

    hep-phNPB(2026)·0 citations
24. 24*

    Self-consistent computation of pair production from non-relativistic effective field theories in the Keldysh-Schwinger formalism

    Tobias Binder🇩🇪 · Edward Wang🇩🇪

    Sommerfeld-enhanced annihilation cross sections in the presence of nearly zero-energy bound states can become so large that perturbative partial-wave unitarity appears to be violated. Previous literature incorporated the short-distance annihilation potential self-consistently into the computation of the Schrödinger wave function at the origin, leading to the unitarization of the Sommerfeld effect in vacuum. We employ non-relativistic effective field theory methods and the Keldysh-Schwinger formalism to additionally include pair-creation effects in the self-consistent computation of four-point correlation functions, which renders the unitarization temperature dependent. Up to small thermal corrections in the non-relativistic and dilute regime of the pairs, we confirm the previous results based on the Schrödinger equation approach for scattering states in vacuum. For the first time, we analyze bound-state contributions beyond their leading decay via annihilation. Interestingly, our self-consistent computation of the four-point correlation function shows that bound states remain on-shell in their out-of-equilibrium decay, even though their spectral functions take the form of Breit-Wigner distributions due to finite decay widths. While this may appear paradoxical, it aligns with expectations from earlier results based on exact analytic solutions of the Kadanoff-Baym equations for a decaying elementary particle in a thermal environment.

    hep-ph3 citations
25. 25*

    Quantum simulating multi-particle processes in high energy nuclear physics: dijet production and color (de)coherence

    João Barata🇨🇭 · Meijian Li🇪🇸 · Wenyang Qian🇪🇸 · Carlos A. Salgado🇪🇸 · João M. Silva🇵🇹

    Hard scattering events in high-energy collisions produce highly virtual partons that subsequently fragment into collimated hadronic cascades. When such partonic showers evolve in a QCD medium, as in deep-inelastic scattering or heavy-ion collisions, the resulting multi-particle distributions encode information about the surrounding matter. Decades of theoretical developments have led to a consistent and order-by-order improvable perturbative description of the shower. This description needs, however, the non-perturbative input that encodes the structure of the hadronic matter. The determination of such input remains challenging within conventional computational approaches, thereby limiting the applicability of the approach. In this work, we develop a framework that employs quantum simulation techniques to compute multi-particle processes in such environments by mapping partonic cross-sections to quantum circuits. As benchmarks, we analyze dipole formation and the QCD antenna radiation pattern at leading order in the strong coupling constant, comparing the results with analytic estimates in simplified limits. The quantum circuit formulation here introduced naturally extends to higher perturbative orders and enables amplitude-level computations in complex matter backgrounds. This provides a systematic foundation for applying quantum information science methods to study multi-particle dynamics in QCD media.

    hep-phnucl-thquant-phJHEP(2026)·7 citations
26. 26*

    All-charm tetraquarks at hadron colliders: A high-precision fragmentation perspective

    Francesco Giovanni Celiberto🇪🇸

    We present the TQ4Q2.0 fragmentation functions for the production of all-heavy (fully heavy) $S$-wave tetraquarks ($T_{4Q}$) with scalar ($0^{++}$), axial-vector ($1^{+-}$), and tensor ($2^{++}$) quantum numbers in high-energy hadronic collisions. This work extends the previous TQ4Q1.1 framework by incorporating nonconstituent heavy-quark contributions and introducing a replica-based uncertainty-quantification strategy derived from multi-scale variations (MHOUs). The construction follows a nonrelativistic QCD factorization approach, combining gluon- and heavy-quark-initiated fragmentation channels at leading power. Initial-scale inputs are modeled through updated potential-inspired wave functions, while the subsequent DGLAP evolution is performed via the threshold-aware HF-NRevo scheme. A comprehensive systematic analysis of uncertainties is carried out, with contributions from color-composite long-distance matrix elements (LDMEs) and perturbative multiscale inputs. The resulting TQ4Q2.0 grids, publicly released in LHAPDF6 format, provide the first complete phenomenological set for all-heavy exotics, enabling precise studies of all-charm tetraquark production and jet-associated observables within the JETHAD environment. This article completes the high-energy resummation-driven generation of the TQ4Q program and establishes a definitive baseline for future collider-oriented analyses of all-heavy multiquark dynamics.

    hep-phhep-exhep-thnucl-ex+1PRD(2026)·7 citations
27. 27*

    Quantum entanglement in electron-nucleus collisions: Role of the linearly polarized gluon distribution

    Michael Fucilla🇵🇱 · Yoshitaka Hatta🇺🇸 · Bo-Wen Xiao🇨🇳

    We calculate the spin density matrix of a back-to-back quark-antiquark pair inclusively produced in electron-nucleus scattering, taking into account the gluon saturation effect and the linearly polarized gluon distribution. We then investigate concurrence and stabilizer Rényi entropy, quantifying entanglement, Bell-nonlocality, and magic. We find that the linearly polarized gluon distribution tends to enhance the entanglement of a heavy quark pair when the total and relative transverse momenta of the pair are orthogonal.

    hep-phPRD(2026)·12 citations
28. 28*

    Spin-Momentum Decoupling in Quarkonium Hadronization: Polarization Quenching via Environment-Induced Decoherence in Jets

    Yi Yang🇹🇼

    The suppression of heavy quarkonium polarization at high transverse momentum ($p_T$) remains a persistent puzzle in quantum chromodynamics (QCD). We propose an effective open-quantum-system paradigm demonstrating that the heavy quark spin state and its macroscopic momentum effectively decouple during hadronization. By retaining the short-distance non-relativistic QCD (NRQCD) perturbative calculations as a kinematic baseline, we argue that the immense kinematic inertia at high $p_T$ parametrically preserves the power-law momentum spectrum. Concurrently, the intense, stochastic chromo-electric background within a fragmenting jet acts as a dynamic decoherence environment. Using a horizon-inspired picture as a physically motivated parametrization, we derive an effective temperature $T_{\text{eff}}(z)\propto \sqrt{\ln (1/z)}$ driven by the multiplicity of soft accompanying partons. By incorporating this effective temperature into a Lindblad dissipation framework, we predict a simultaneous quenching of the polar and azimuthal anisotropies towards a maximally mixed state. Crucially, the recently observed ``soft'' fragmentation of ${\rm Y}(nS)$ by the CMS Collaboration provides a highly consistent phase-space weighting required in our framework to explain the historical inclusive unpolarized anomaly. Identifying the fragmentation fraction $z=p_T^{\mathcal{Q}}/p_T^{\text{jet}}$ as the critical control variable, we propose that a key testable prediction is the simultaneous $z$-dependent suppression of ${\lambda }_{\theta }$, ${\lambda }_{\varphi }$, and $\tilde{\lambda }$ in fixed quarkonium and jet $p_T$ bins.

    hep-phhep-ex0 citations
29. 29*

    Grand Unified Origin of Enhanced Scalar Couplings: Connecting Radiative Electroweak Symmetry Breaking to SO(10) Dynamics

    Farrukh A. Chishtie🇨🇦

    We propose that the enhanced Higgs quartic coupling required by radiatively broken electroweak symmetry (RBEWS) emerges naturally from SO(10) grand unification. Our previous analysis demonstrated that a coupling enhancement factor $k={\lambda }_{\mathrm{enhanced}}/{\lambda }_{\mathrm{SM}}$ leads to absolute vacuum stability with a UV Landau pole near the GUT scale for $k\gtrsim 1.03$. The RBEWS prediction $e_{125}=7.2$ of Steele and Wang, when properly translated from the Coleman-Weinberg scheme at the electroweak VEV to the $\overline{\mathrm{MS}}$ scheme at $M_t$ via scheme conversion and scale-dependent ratio evolution, yields $k(M_t)\approx 6.0$--$6.4$, corresponding to a UV pole at ${\Lambda }_{\mathrm{UV}}\sim 1.5\text{–}2\times 10^{16}$~GeV -- remarkably close to the GUT scale $M_{\mathrm{GUT}}\sim 2\times 10^{16}$~GeV. We argue this coincidence is not accidental: the UV pole signals the scale where the Standard Model effective description must be embedded into the full SO(10) structure. We derive threshold corrections from SO(10) scalar sectors containing ${10}_H$, ${\overline{126}}_H$, and ${45}_H$ representations, showing that portal couplings between the light Higgs doublet and heavy GUT scalars can generate enhancement factors of order $k\sim 5$--$10$ at the matching scale. The Coleman-Weinberg mechanism operating within a classically scale-invariant GUT scalar potential provides a dynamical origin for both RBEWS and the hierarchy between $M_{\mathrm{GUT}}$ and the electroweak scale.

    hep-phhep-exhep-thPLB(2026)·1 citation
30. 30*

    Spin Correlation and Quantum Entanglement of Fermion Pairs in Transversely Polarized $e^{-}{e}^{+}$ Collisions

    Yi-Jing Fang🇨🇳 · Amit Bhoonah🇺🇸 · Kun Cheng🇺🇸 · Tao Han🇺🇸 · Yandong Liu🇨🇳 · Hao Zhang🇨🇳

    We systematically study the spin correlations and quantum entanglement in transversely polarized electron-positron collisions. We find that the $s$-channel QED process $e^{-}{e}^{+}\to f\bar{f}$ produces a maximally entangled state in the entire phase space when the initial beams are transversely polarized, while the quantum magic varies in different phase space points for the maximally entangled Bell states. For electroweak processes, the spin configuration of final states depends on chiral couplings, and the entanglement is also greatly enhanced by transverse polarization as in the QED process. For Bhabha scattering with additional $t$-channel contributions, the transverse polarization still increases the final state entanglement, although with some dilution. The sensitive dependence of final spin states on the transverse polarization makes the beam polarization a powerful tool for generating and controlling quantum entanglement in collider experiments, opening up new opportunities for quantum information studies at high-energy colliders.

    hep-ph19 citations
31. 31*

    ALP production in Lepton Flavour Violating meson, tau and gauge boson decays

    Marco Ardu🇪🇸 · Lorenzo Calibbi🇨🇳 · Marco Fedele🇩🇪 · Federico Mescia🇮🇹

    In this paper we study axion-like particles (ALPs) with lepton-flavour-violating (LFV) couplings in the mass regime above the muon threshold, $m_a>m_{\mu }$, where the strong bound from the exotic muon decay $\mu \to ea$ no longer apply and the decay channel $a\to e\mu$ becomes kinematically accessible. In this region, the ALP typically decays promptly, motivating new search strategies based on its production in decays involving virtual muons. We analyse charged-meson and $W$ decays, neutral-current processes such as $Z$ and quarkonium decays, and, when couplings to the third generation are present, LFV $\tau$ decays. The subsequent decay $a\to e\mu$ leads to striking LFV signatures with negligible Standard Model backgrounds. Combining these production modes with current low-energy constraints, we assess the sensitivity of future high-energy $e^{+}{e}^{-}$ colliders, flavour factories such as Belle II and STCF, fixed-target experiments such as NA62, and proton beam-dump facilities such as SHiP. Overall, our results identify LFV ALP production in meson, gauge-boson, quarkonium and $\tau$ decays (with displaced vertices) as a promising and largely unexplored avenue to test ALP interactions with charged leptons above the muon mass threshold.

    hep-phhep-exJHEP(2026)·2 citations
32. 32*

    $S$-matrix calculation of $BQ$ correlation at finite baryon density

    Vojtech Honek🇸🇰 · Pok Man Lo🇵🇱 · Boris Tomasik🇸🇰

    We calculate the baryon number--electric charge susceptibility at non-vanishing baryo-chemical potential within the model of hadron gas where pion-nucleon interaction is accounted for by the $S$-matrix formalism. The susceptibility is largely increased when the chemical potential grows within a phenomenologically relevant interval. The results are then evaluated along the chemical freeze-out line. We also calculate the evolution of the susceptibility in a cooling fireball by making use of the Partial Chemical Equilibrium model.

    ↳ nucl-thhep-ph1 citation
33. 33*

    Possible Supermassive Dark Object Composed of Light Fermionic Gas with an Embedded Neutron Star Core

    Daichen Zou🇨🇳 · Xudong Wang🇨🇳 · Bin Qi🇨🇳

    The structure of dark matter admixed neutron stars (DANSs) are investigated, adopting a non-annihilating self-interacting fermionic dark matter (DM) model, with a particular focus on the case of the light DM particle mass $m_D\in [10^{-10},1]$ GeV. The DANSs become DM-dominated configurations when $m_D<10^{-1}$ GeV, where a compact neutron star core becomes embedded within an extremely large DM halo. It is found that the maximum mass of DANSs is inversely proportional to $m_D$, approximately as $0.627(GeV/m_{\mathrm{D}}{)}^2{\mathrm{M}}_{\odot }$, which implies that extremely large masses can be achieved for small $m_{\mathrm{D}}$. For $m_D\sim 5\times 10^{-4}$ GeV, the calculated mass and size of the DM halo can be comparable to those of supermassive black holes such as Sgr A*. Our findings hint at a scenario where neutron stars might serve as strong gravitational seeds for such supermassive dark objects.

    ↳ astro-ph.GAhep-phnucl-th0 citations
34. 34*

    Understanding the structure of nucleon excitations from their wavefunctions

    Jackson A. Mickley🇦🇺 · Waseem Kamleh🇦🇺 · Derek B. Leinweber🇦🇺 · Finn M. Stokes🇦🇺

    Relativistic wavefunctions of nucleon excitations are scrutinised to understand their node structure and the underlying role of local interpolating fields in generating the nucleon spectrum. In addressing quark model perspectives, approximately 4000 propagators are employed on the heaviest PACS-CS ensemble at $m_{\pi }\simeq$ 702 MeV. We examine the ground and four lowest-lying excited states at zero momentum for both positive- and negative-parity spectra, where the proton's d-quark wavefunction is calculated about the two u quarks at the origin. This is achieved using two local interpolating fields that each carry the quantum numbers of the nucleon but with differing spin-flavour structures, one of which vanishes in the nonrelativistic limit. We find that two distinct types of wavefunction nodes are manifest: "superposition nodes" formed through a linear combination of interpolating fields, and novel "built-in nodes" that are fundamentally built in to the s-wave Dirac components of an individual interpolating field. These are investigated qualitatively through visualisations in the form of both volume and surface renderings, and quantitatively by the calculation of radial wavefunctions. Combined, these findings build a comprehensive picture of the single-particle nucleon spectrum and how its properties derive from fundamental lattice operators.

    ↳ hep-lathep-phnucl-thPRD(2026)·0 citations
35. 35*

    Characterizing entanglement dynamics in QED scattering processes

    Massimo Blasone🇮🇹 · Silvio De Siena🇧🇷 · Gaetano Lambiase🇮🇹 · Bruno Micciola🇮🇹 · Kyrylo Simonov

    We study entanglement dynamics among helicity degrees of freedom in quantum electrodynamics (QED) scattering processes. For generic initial states, we consider scattering at fixed momentum, corresponding to a generalized measurement described by a positive operator-valued measure, resulting in a post-measurement state. Such processes are modeled in terms of quantum maps, whose spectral structure fully determines the associated entanglement dynamics. For scattering involving fermions only, maximal entanglement present in the initial state is always preserved. Moreover, iterating the corresponding quantum maps on arbitrary initial states, we obtain the fixed points of the maps, which, in the largest number of cases, are asymptotic (pure) maximally entangled states. The structure of the maps also accounts for the entanglement dynamics in processes involving both fermions and photons. The defining properties of these maps originate from discrete symmetries of the QED interaction.

    ↳ quant-phhep-phChaos Solitons Fractals(2025)·8 citations
36. 36*

    An Analytic Formalism of Inflation for Derivative Coupled Scalar Field and Validating its predictions for Some Inflationary Potentials

    Aayush Randeep🇮🇳 · Rajib Saha🇮🇳

    One of the fundamental objectives of contemporary cosmology is to understand the physics of the inflationary universe, owing to its observably verifiable predictions about the very early universe with an energy scale of $\sim 10^{16}$ GeV. Recent observations from the ACT and the Planck mission, constrain the values of the scalar spectral index, $n_s$, and the tensor-to-scalar ratio, with state-of-the-art accuracy and upper limits, respectively. In the current work, a type of non minimally coupled inflationary model in which the gravity and the background scalar field interact through a covariant product of the Ricci tensor and derivatives of the scalar field. With this interaction at the backdrop, we estimate $n_s$ and $r$ for a wide range of inflaton self-interaction potentials, including power law, exponential $\alpha$ attractor, Arctan, Hilltop, and polynomial model. We show that the higher derivative terms involving the scalar field resulting from the derivative coupling term can be handled without facing any singularity within the slow-roll regime. We show that it is possible to produce $n_s$ and $r$ values consistent with ACT and Planck observations for each of the chosen sets of potentials for the derivative coupled action.

    ↳ astro-ph.COgr-qchep-phhep-th0 citations
37. 37*

    Complementary Approach to Anisotropic Flows in Heavy-Ion Collisions

    E. Dlin🇷🇺 · O. Teryaev🇷🇺

    We introduce a no-reaction-plane (no-RP) method for extracting directed (\(v_1\)) and elliptic (\(v_2\)) flows in heavy-ion collisions, which eliminates the need for event-plane reconstruction. %by scanning over fixed test angles and using simple count asymmetries. The method is validated with PHSD model simulations of Au+Au collisions at \(\sqrt{s_{NN}} = 9.2\) GeV at freeze-out (for impact parameters \(b = 4-8\) fm). We demonstrate that the two asymmetries for each harmonic contribute equally, i.e., \(\langle A_{\mathrm{ud}}^2\rangle \approx \langle A_{\mathrm{lr}}^2\rangle\) and \(\langle A_1^2\rangle \approx \langle A_2^2\rangle\), so that a single asymmetry measurement suffices for a good flow estimate. Event-by-event comparisons with direct calculations using the true reaction plane yield Pearson correlation coefficients of 0.956 for \(v_2\) and 0.834 for \(v_1\), confirming that the no-RP method captures flow fluctuations well enough.

    ↳ nucl-thhep-phnucl-ex0 citations
38. 38*

    Sensitivity of Neutron Star Observables to Transition Density in Hybrid Equation-of-State Models

    N. K. Patra🇨🇳 · Sk Md Adil Imam🇨🇱 · Kai Zhou🇺🇸

    We investigate how the transition density \(\rho_{tr}\) affects hybrid constructions of the neutron-star equation of state (EoS) in which a nucleonic description at low densities is matched to a model-agnostic high-density extension based on a speed-of-sound parametrization. Using four representative nucleonic models--Taylor expansion, \(\frac{n}{3}\) expansion, Skyrme, and relativistic mean-field--built from identical nuclear matter parameters, we isolate the impact of the low-density EoS and the transition density on neutron star observables. We find that, within the present smooth-matching prescription, neutron star properties such as radii and tidal deformabilities retain significant sensitivity to the choice of low-density EoS for commonly adopted transition densities around \(\rho_{tr} \approx 2\rho_0\), even when the same high-density parametrization is employed. This residual dependence arises from differences in the matching conditions at \(\rho_{tr}\), which propagate into the high-density extension, so different low-density inputs lead to different effective high-density EoSs. These findings are robust across two distinct speed-of-sound parametrizations. Quantitatively, the model spread in radius and tidal deformability at $1.4M_{\odot }$ exceeds the current observational uncertainty by factors of $\sim 1.8$ and $\sim 1.4$ at ${\rho }_{\mathrm{tr}}\approx 2{\rho }_0$, whereas these factors reduce to $\sim 1.05$ and $\sim 0.4$ at ${\rho }_{\mathrm{tr}}={\rho }_0$. Lowering the transition density, therefore, systematically diminishes the spread among models and leads to more consistent predictions. Our results demonstrate that the widely used choice \(\rho_{tr} \approx 2\rho_0\) does not guarantee model independence in hybrid EoS constructions, and should be treated as an explicit source of systematic uncertainty when inferring dense matter properties from neutron star observations.

    ↳ nucl-thastro-ph.HEastro-ph.SRgr-qc+1PRD(2026)·0 citations
39. 39*

    Topological charge of fermions and Landau theory of Fermi liquid

    G.E. Volovik🇷🇺

    In the fermionic liquids, the Fermi surface is topologically stable,\cite{Volovik2003} which is at the origin of the applicability of the Landau theory of Fermi liquid (LFL). The LFL exists under special condition, when the Green's function has a pole with nonzero residue $Z$. Otherwise one has non-Landau Fermi liquid (NLFL), such as Luttinger liquid, which is described by the same topological invariant. It appears that in general this topological invariant is the property of the fermionic particle, i.e. the particle charge (or the electric charge of electron) is equivalent to the topological charge of the fermion. The conservation of the fermionic charge is equivalent to the conservation of the topological charge. We consider the application of this topological charge to the Landau theory of Fermi liquids. We also consider the application to non-Fermi liquids and crystalline insulators in relation to the Luttinger theorem.

    ↳ cond-mat.str-elhep-ph0 citations
40. 40*

    Nonlinear response of flow harmonics in Gubser flow with participant-reaction planes mismatch

    Xiang Ren🇨🇳 · Jin-Yu Hu🇨🇳 · Hao-jie Xu🇨🇳 · Shi Pu🇨🇳

    We investigate the nonlinear response of flow harmonics $v_2,v_4$ to initial-state eccentricities ${ϵ}_2,{ϵ}_4$ within the Gubser-flow framework. By extending the perturbative solutions of Gubser flow, we derive analytic nonlinear response relations connecting the eccentricities ${ϵ}_2,{ϵ}_4$ to the flow harmonics $v_2,v_4$. Our results reproduce the well-known result $v_4/v_2^2\to 1/2$ in large transverse momentum $p_T$ limit. Furthermore, we study the effects of a mismatch between the participant and reaction planes. We find that the conventional nonlinear response coefficients acquire an additional factor determined by the participant-plane angles, which is often approximated as statistical noise driven by event-by-event fluctuations. This factor can modify both the strength but even the sign of the effective nonlinear response coefficient, making it sensitive to the initial configuration of the colliding nuclei. Our study provides new analytical insight into the origin of collective phenomena in relativistic heavy-ion collisions.

    ↳ nucl-thhep-phnucl-exPRD(2026)·2 citations
41. 41*

    GeV gamma-ray emission in the field of the shell-type supernova remnant Vela Jr revisited

    Ting-Ting Ge🇨🇳 · Qi-Hang Wu🇨🇳 · Pak-Hin Thomas Tam🇨🇳 · Jie Feng🇨🇳 · Hai-Feng Zhou🇨🇳 · Kai Wang🇨🇳 · Su-Jie Lin🇨🇳

    We present an updated analysis of the gigaelectronvolt (GeV) gamma-ray emission from the shell-type supernova remnant (SNR) RX J0852.0-4622 (Vela Jr) using 15 yr of Fermi Large Area Telescope (Fermi-LAT) data. We quantitatively model the GeV morphology and find that it is best described by the masked H.E.S.S. shell template, indicating that the embedded pulsar wind nebula (PWN) contributes little to the GeV flux. The 0.1-500 GeV spectrum is well fitted by a hard power law with a photon index of $1.77\pm 0.03$ and connects smoothly to the teraelectronvolt (TeV) spectrum, confirming previous results with improved precision. We further construct an independent eROSITA shell template and derive the 1-5 keV X-ray spectral energy distribution (SED) of the whole remnant, which provides new constraints on the synchrotron emission. We model the multi-wavelength (MWL) SED with a pure leptonic model and a hybrid lepton-hadron model. While the pure leptonic model reproduces the overall broadband shape, the hybrid model provides a better statistical description of the same dataset, supporting a mixed-origin picture in which the hadronic contribution is mainly relevant in the GeV band and the TeV emission remains predominantly leptonic.

    ↳ astro-ph.HEhep-phMNRAS(2026)·0 citations
42. 42*

    Arbitrary-Velocity Volkov Wavepackets

    D. Ramsey🇺🇸 · J. McKeown · J. P. Palastro🇺🇸

    The evolution of a charged lepton in the field of an electromagnetic plane wave can be described as a superposition of Volkov states. Here we demonstrate that imposing specific momentum correlations among Volkov states produces a spatiotemporally structured wavepacket whose probability-density peak travels at an arbitrary, tailored velocity. This velocity can be chosen independently of both the field amplitude and the velocity expectation value. The imposed momentum correlations modify the expectation-value trajectory, providing a measurable signature of the arbitrary velocity within a physical observable.

    ↳ quant-phhep-ph1 citation
43. 43*

    SemiCharmTag: a tool for Semileptonic Charm tagging

    Carolina Arata🇫🇷 · Imanol Corredoira🇫🇷 · Alisha Lightbody🇫🇷 · Michael Winn🇫🇷

    A method for selecting and/or rejecting leptons from charm semileptonic decays based on the tagging of the secondary vertex using a hadron track is introduced. The method is developed for dimuon Drell-Yan measurements in LHCb using full simulations in proton-proton collisions at $\sqrt{s}=13.6$ TeV. We focus on the invariant mass range between 2.9 and 5 GeV/$c^2$ with single muon transverse momentum larger than 1 GeV/$c$. A novel strategy is detailed for background rejection, achieving an improvement of the signal over background of a factor $\sim 4$ at an efficiency of 81% while maintaining the Drell-Yan kinematic distributions largely unbiased except at the acceptance edges. Moreover, a second approach is presented for the construction of unbiased background-pure samples of single muons from charm decays, achieving a charm efficiency of 21.4% at a Drell-Yan efficiency of 1.1%.

    ↳ hep-exhep-phnucl-ex0 citations
44. 44*

    Morphological false-vacuum decay in dipolar supersolids

    Wyatt Kirkby🇩🇪 · Lauriane Chomaz🇩🇪 · Thomas Gasenzer🇩🇪

    False-vacuum decay between two morphologically distinct supersolid phases via bubble nucleation is studied in a uniform dipolar gas confined to the plane. Starting from a metastable honeycomb state, the formation of stripe phase domains is simulated numerically by means of a stochastic projected extended Gross-Pitaevskii equation. The speed of bubble growth is analyzed in relation to the multiple speeds of sound of the supersolid, and is found to be set by the slowest of these sounds. The vacuum decay rate is numerically extracted and compared against a minimal effective model for the Coleman bounce solution connecting the two supersolid orders. Our results establish dipolar supersolids as a novel and versatile platform for studying false-vacuum decay. This setting offers a rich structure of metastable states and collective excitations that come into play in the decay. Furthermore, here, in contrast to previous studies, bubble formation occurs directly in the real-space density and can be probed with \textit{in situ} imaging.

    ↳ cond-mat.quant-gashep-ph1 citation
45. 45*

    An AI-based Detector Simulation and Reconstruction Model for the ALEPH Experiment at LEP

    Ya-Feng Lo🇺🇸 · Dmitrii Kobylianskii🇮🇱 · Benjamin Nachman🇺🇸 · Eilam Gross🇮🇱

    We present the application of Parnassus, a generative model for full detector simulation and reconstruction, to the ALEPH detector at the Large Electron-Positron Collider (LEP). Training on simulated $e^{+}{e}^{-}$ to Z to qqbar events processed through the ALEPH detector simulation and reconstruction, we demonstrate that Parnassus faithfully reproduces the detector response at the event, jet, and particle levels, with substantially better agreement than the Delphes fast simulation. The clean $e^{+}{e}^{-}$ environment, free of pileup and characterized by simple event topologies, provides a well-controlled benchmark for evaluating the generative model's fidelity. Our results demonstrate that modern neural-network-based generative simulation approaches, developed primarily for LHC experiments, generalize naturally to historical collider experiments with distinct detector geometries and physics environments. This work shows that Parnassus can be applied beyond the LHC context and serves as an important tool for legacy data analysis where archival software tools are challenging to resurrect.

    ↳ physics.ins-dethep-exhep-ph3 citations
46. 46*

    Gravitational wave signatures and periodic orbits of a charged black hole in a Hernquist dark matter halo

    N. Heidari🇧🇷 · A. A. Araujo Filho🇧🇷 · Iarley P. Lobo🇧🇷

    In this work, we study the motion of massive test particles and the gravitational--wave emission associated with periodic trajectories around a magnetically charged black hole immersed in a \textit{Hernquist} dark matter halo. We begin by analyzing the effective potential and the conditions for stable motion, with particular attention to the marginally bound radius and the innermost stable circular orbit. Our results show that the dark matter parameters, namely the halo density and scale radius, enlarge the allowed region and generally shift the relevant characteristic radii and angular momenta toward larger values. In contrast, the magnetic charge partially counterbalances this behavior. We then examine periodic trajectories through the rational number $q$, which characterizes the relation between the azimuthal and radial frequencies, and construct representative zoom--whirl configurations together with their precessing counterparts. Finally, we investigate the imprints of dark matter and magnetic monopole charge on the gravitational--wave polarizations in the extreme mass--ratio regime.

    ↳ gr-qchep-ph5 citations
47. 47*

    Novel ringdown tests of general relativity with black hole greybody factors

    Romeo Felice Rosato🇮🇹 · Francesco Crescimbeni🇮🇹 · Sophia Yi🇺🇸 · Emanuele Berti🇺🇸 · Paolo Pani🇮🇹

    We present GreyRing, a new model for the post-merger signal in black-hole binary coalescences based on the greybody factor of the remnant. The model accurately reproduces the full frequency-domain ringdown signal of a large set of comparable-mass, aligned-spin numerical relativity waveforms, achieving mismatches of order $\mathcal{O}(10^{-6})$ for the dominant $(\ell ,m)=(2,2)$ mode, and typically outperforming state-of-the-art time-domain models. Building on this model, we introduce a novel consistency test of strong gravity based on the greybody factor: the remnant mass and spin inferred from GreyRing can be compared with those obtained through standard black hole spectroscopy. This agnostic test relies exclusively on the post-merger signal and does not require the inclusion of overtones or the choice of very early ringdown starting times, combining the advantages of inspiral-merger-ringdown consistency tests and traditional black hole spectroscopy. We apply the test to GW250114 and find that the remnant mass and spin inferred from GreyRing are consistent with those measured from the full signal. Remarkably, the inferred parameters can be measured with a precision comparable to, or slightly better than, that achieved with standard black-hole spectroscopy. Our greybody-factor waveform model allows for new precision tests of strong gravity using the ringdown signal.

    ↳ gr-qcastro-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.