Wed·Nov 12, 2025Wednesday·November 12, 2025

1. 01*

   Prompt diphoton production compared to measurements at 13 TeV in $k_t$-factorization: A comparative analysis of unintegrated PDF models

   The CHROMA Collaboration: R. Kord Valeshabadi🇮🇷 · S. Rezaie🇮🇷 · K. Azizi🇮🇷

   We perform an in-depth comparative analysis of unintegrated parton distribution function (UPDF) models for isolated prompt diphoton production in proton-proton collisions at $\sqrt{s}=13$~TeV within the $k_t$-factorization framework. Predictions are obtained with three UPDF approaches: Parton Branching (PB), NLO-MRW, and Modified KMRW (MKMRW). Tree-level $q+\bar{q}\to \gamma +\gamma$, $q+\bar{q}\to \gamma +\gamma +g$, and $q+g\to \gamma +\gamma +q$ subprocesses are generated with \textsc{KaTie} using off-shell initial states; the loop-induced $g+g\to \gamma +\gamma$ channel is evaluated independently. We compare differential cross sections with ATLAS measurements across a broad set of observables, including the photon transverse momenta, diphoton invariant mass and transverse momentum, the Collins-Soper angle, acoplanarity, ${\varphi }_{\eta }^{\ast }$, and a transverse thrust-related variable. This comparative study quantifies the impact of the UPDF choice on the diphoton spectra. We find that the PB model provides the most consistent agreement over all distributions, whereas NLO-MRW tends to overshoot in regions correlated with larger factorization scales and MKMRW generally undershoots due to stronger Sudakov suppression. With standard scale variations, our results indicate that $k_t$-factorization with PB UPDFs can accurately describe diphoton production, while fixed-order collinear predictions typically require higher-order corrections together with parton-shower effects to achieve a comparable description.

   hep-phhep-exhep-latPRD(2026)·1 citation
2. 02*

   Unified Pati-Salam from Noncommutative Geometry: Overview and Phenomenological Remarks

   Ufuk Aydemir🇹🇷

   The lack of clear new-physics signals at the LHC searches motivates models that can guide current and future collider searches. The spectral action principle within the noncommutative geometry (NCG) framework yields such models with distinctive phenomenology. This formalism derives the actions of the Standard Model, General Relativity, and beyond from the underlying algebra, putting them on a common geometric footing. Certain versions of Pati-Salam (PS) models with gauge coupling unification and limited scalar content can be derived from an appropriate noncommutative algebra. In this paper, I review these gauge-coupling-unified Pati-Salam models and discuss their phenomenological aspects, focusing on the $S_1$ scalar leptoquark.

   hep-phhep-thBled Workshops Phys.(2025)·0 citations
3. 03*

   Parametrisation and dictionary for CP violating Higgs boson interactions

   Daniele Barducci🇮🇹 · Matthew Forslund🇺🇸 · Marta Fuentes Zamoro🇪🇸 · Pier Paolo Giardino🇪🇸 · Andrei V. Gritsan🇺🇸 · Giacomo Ortona🇮🇹

   Searches for charge-parity (CP) violating interactions of the Standard Model (SM) Higgs boson are a key priority of the LHC physics program. Experimental results from ATLAS and CMS are often reinterpreted within a variety of theoretical parametrisations, the most commonly used being the Higgs basis, $\kappa$'s and angles, CP fractions and effective field theories (EFT) such as the SMEFT and the Higgs EFT. However, differing conventions and assumptions across the literature make the translation between these parametrisations nontrivial and prone to inconsistencies. In this paper, we provide a unified framework and construct explicit dictionaries connecting these different approaches. This facilitates a transparent comparison between theoretical studies and experimental analyses, enabling more robust interpretations of CP violating effects in Higgs boson interactions.

   hep-phhep-exSciPost Phys.Comm.Rep.(2026)·4 citations
4. 04*

   Scalar-Magnetometer Search for Ultralight Dark Photon Dark Matter with a Single-Site, Two-Sensor Array: A 6-Channel DTFT Likelihood Analysis with Scalar Optically Pumped Magnetometers

   Peisen Zhao🇩🇪 · Ole Behrens🇩🇪 · Maja Benning🇩🇪 · Peter Fierlinger🇩🇪 · Xuefen Han🇩🇪 · Maximilian Huber🇨🇦 · Florian Kuchler🇩🇪 · Yevgeny V. Stadnik🇦🇺 · Philipp Wunderl🇩🇪

   We report on a laboratory search for ultralight dark photon dark matter using a single-site, two-sensor scalar magnetometer array. The experiment employs two scalar optically pumped magnetometers (OPMs) operated in a differential configuration to suppress common-mode noise and enhance sensitivity to spatially coherent dark photon fields. We analyze 10.5 hours of continuous data with a six-channel complex data vector evaluated at the three physical frequencies of the expected dark photon signal triplet. Assuming Gaussian noise, we develop a likelihood framework to set robust, frequency-resolved upper limits on the kinetic-mixing parameter $\epsilon$, which governs the coupling between Standard Model photons and dark photons. Within the mass range $4\times 10^{-15}\mathrm{eV}\le m_{A^{\prime }}\le 3\times 10^{-14}\mathrm{eV}$, we obtain the most stringent direct laboratory limits to date on $\epsilon$, complementing existing astrophysical bounds including those inferred from observations of the Leo-T dwarf galaxy.

   hep-phPRD(2025)·2 citations
5. 05*

   $\varphi$ and $J/\psi$ Production in Proton-Proton Scattering through Hadronic Molecules

   Di Ben🇨🇳 · Bing-Song Zou🇨🇳

   This study estimates the contributions of hidden-strangeness hadronic molecular states ($N(2080)3/2^{-}$, $N(2270)3/2^{-}$) to $\varphi$ production and hidden-charm $P_c$ states to $J/\psi$ production in $pp$ collisions. The calculated cross-sections reach $\sim 10\mu b$ for $pp\to pp\varphi$ and $\sim 0.1nb$ for $pp\to ppJ/\psi$ at energies $\sim 2$~GeV above threshold. We also compute the spin density matrix element ${\rho }_{00}$ and the decay angular distributions for $\varphi \to K^{+}{K}^{-}$ and $J/\psi \to {\mu }^{+}{\mu }^{-}$. To support future experiments, we conduct Monte Carlo simulations for the four-body final states of $pp\to pp{K}^{+}{K}^{-}$ and $pp\to pp{\mu }^{+}{\mu }^{-}$. The resulting lab-frame distributions are expected to inform detector design at facilities like the High-Intensity heavy-ion Accelerator Facility (HIAF) and the proposed Chinese Advanced Nuclear Physics Research Facility (CNUF), enabling more precise measurements and tighter theoretical constraints. Furthermore, to explain the STAR collaboration's result on $\varphi$ meson spin alignment in heavy-ion collisions, we propose a novel mechanism involving hidden-strangeness molecular states, testable with future high-statistics $pp\to pp\varphi$ data.

   hep-phnucl-th0 citations
6. 06*

   Novel bounds on neutrino portal dark matter from leptonic meson decays

   Shohei Okawa🇰🇷 · Yuji Omura🇯🇵

   We investigate the potential of leptonic meson decays $M\to \ell {\bar{\nu }}_{\ell }$, where $M$ is a pseudo-scalar meson, as a probe of neutrino portal dark matter. The model of our focus features a neutral fermion $\psi$ and scalar $\varphi$, which are coupled predominantly to neutrinos in the form $\mathcal{L}\supset \lambda {\overline{\nu }}_L\varphi {\psi }_R$. This interaction generates two corrections to the $M\to \ell {\bar{\nu }}_{\ell }$ observables. The first one is a novel three-body decay process $M\to \ell \bar{\psi }\varphi$. This process is enabled by the splitting of the off-shell anti-neutrino ${\bar{\nu }}_{\ell }$ into $\psi$ and $\varphi$ in the $M\to \ell {\bar{\nu }}_{\ell }$ diagram. The helicity suppression in $M\to \ell {\bar{\nu }}_{\ell }$ is absent in the three-body process, thereby forming a potentially large contribution to real experimental results, provided $\psi$ and $\varphi$ are invisible. The second one is one-loop radiative corrections to the weak vertex $W\ell {\bar{\nu }}_{\ell }$, which do not modify the charged lepton spectrum but lead to enhancement or suppression of the partial $M\to \ell {\bar{\nu }}_{\ell }$ decay width. To demonstrate the ability of the leptonic meson decays to probe the neutrino portal dark matter, we compute two corrections analytically and compare the modified meson branching ratios with the experimental data on the lepton flavor universality of pion and Kaon decays. The resulting constraints turn out to surpass the existing bounds in a large part of parameter spaces.

   hep-phhep-exJHEP(2026)·3 citations
7. 07*

   Good flavor search in SU(5): a machine learning approach

   Fayez Abu-Ajamieh🇮🇳 · Shinsuke Kawai🇰🇷 · Nobuchika Okada🇺🇸

   We revisit the fermion mass problem of the $SU(5)$ grand unified theory using machine learning techniques. The original $SU(5)$ model proposed by Georgi and Glashow is incompatible with the observed fermion mass spectrum. Two remedies are known to resolve this discrepancy, one is through introducing a new interaction via a 45-dimensional field, and the other via a 24-dimensional field. We investigate which modification is more beautiful, defining the beauty as proximity to the original Georgi-Glashow $SU(5)$ model. Our analysis shows that, in both supersymmetric and non-supersymmetric scenarios, the model incorporating the interaction with the 24-dimensional field is more beautiful under this criterion. We then generalise these models by introducing a continuous parameter $y$, which takes the value 3 for the 45-dimensional field and 1.5 for the 24-dimensional field. Numerical optimisation reveals that $y\approx 0.8$ yields the closest match to the original $SU(5)$ model, indicating that this value corresponds to the most beautiful model according to our definition.

   hep-phcs.LGhep-thNPB(2026)·3 citations
8. 08*

   Analysis of the strong decay $X(4140)\to J/\psi \varphi$ via the light-cone QCD sum rules

   Zun-Yan Di🇨🇳 · Zhi-Gang Wang🇨🇳

   In this article, we take the $X(4140)$ as the axialvector tetraquark state with the symbolic quark structure $[sc{]}_S[\bar{s}\bar{c}{]}_A+[sc{]}_A[\bar{s}\bar{c}{]}_S$, and calculate the width of the two-body strong decay $X(4140)\to J/\psi \varphi$ within the framework of the light-cone sum rules. Different from the traditional light-cone sum rules, at the phenomenological side, we introduce parameters $C$ to eliminate the contaminations from the higher resonances and continuum states, and match the hadron side with the QCD side of the correlation function based on rigorous quark-hadron duality to obtain the stable QCD sum rules. Then we obtain the decay width $\Gamma (X(4140)\to J/\psi \varphi )=145\pm 21\text{MeV}$, which is reasonable according to the experimental data $162\pm 21_{-49}^{+24}\text{MeV}$ from the LHCb collaboration. The numerical result supports the possibility that the $X(4140)$ could be the $[sc{]}_S[\bar{s}\bar{c}{]}_A+[sc{]}_A[\bar{s}\bar{c}{]}_S$ type axialvector tetraquark state.

   hep-ph0 citations
9. 09*

   Determination of Parton Densities for QCD partons and Electroweak Bosons

   K. Moral Figueroa🇩🇪 · E. Gallo🇩🇪 · H. Jung🇩🇪 · S. Taheri Monfared🇩🇪

   Parton densities are obtained from a solution of the extended DGLAP-type evolution equation that includes both QCD and electroweak contributions. The equations are solved using the Parton-Branching (PB) approach, and the evolution is performed at next-to-leading order for QCD partons and leading order for electroweak bosons. The initial QCD parton distributions are fitted to HERA deep inelastic scattering data, while photon and weak-boson densities are generated perturbatively and validated against $d\sigma /d{Q}^2$. The resulting collinear and transverse-momentum dependent (TMD) densities are provided in LHApdf and TMDlib formats for direct phenomenological use.

   hep-phEPJC(2026)·2 citations
10. 10*

    Probing low-mass dark matter from sub-MeV to sub-GeV with germanium-based quantum phononic spectroscopy

    D.-M. Mei🇺🇸 · N. Budhathoki🇺🇸 · S. A. Panamaldeniya🇺🇸 · K.-M. Dong🇺🇸 · S. Bhattarai🇺🇸 · A. Warren🇺🇸 · A. Prem🇺🇸 · S. Chhetri🇺🇸

    We present a germanium phonon-to-charge transducer that integrates a slow-phonon phononic-crystal (PnC) region with radio-frequency quantum point-contact (RF-QPC) readout at 4 K, and we evaluate its dark-sector reach. A calibrated signal-collection model, which combines geometric guiding, propagation survival, and multiplicity-assisted primary-phonon detection, provides selection-corrected thresholds in the $10^{-3}$-$10^{-2}$~eV range and a background model informed by nanosecond timing gates and GHz-band power-spectral-density windows. Under standard halo assumptions, a 100 g module achieves projected sensitivity to DM-electron and DM-nucleon scattering at recoil energies below $10^{-2}$~eV, probing cross sections below $10^{-43}{\mathrm{cm}}^2$ for $m_{\chi }\in [0.01,100]\mathrm{MeV}/c^2$ (with efficiencies and thresholds folded in). We present sensitivities for both heavy-mediator ($F_{\mathrm{DM}}=1$) and light-mediator ($F_{\mathrm{DM}}\propto 1/q^2$) benchmarks, quantify dominant systematics (threshold, phonon quality factor $Q$, and bulk defect densities), and outline a staged program toward kg$\cdot$yr exposures that begins to test models approaching the solar CE$\nu$NS background.

    hep-phPhys.Dark Univ.(2025)·3 citations
11. 11*

    Future Collider Perspectives on Higgs CP Violation

    Arun Atwal🇬🇧 · Jessica Burridge🇬🇧 · António Jacques Costa🇬🇧 · Christoph Englert🇬🇧 · Sinead Farrington🇬🇧 · Jay Nesbitt🇬🇧 · Leonor Santos Pereira Trigo🇩🇪 · Andrew Pilkington🇬🇧 · Aidan Robson🇬🇧 · Júlia Cardoso Silva🇬🇧 · Sarah Williams🇬🇧 · Yuyang Zhang🇨🇳

    The search for new sources of CP violation is a cornerstone of the beyond the Standard Model phenomenology programme at the LHC and beyond. We provide a comprehensive analysis of such searches at a range of future facilities with the aim of informing the currently unfolding future collider roadmap. Focussing on new sources of CP violation specifically in the gauge-Higgs sector, we demonstrate the outstanding potential held by future electron-positron and proton-proton colliders to reveal and identify BSM physics with direct relevance for the observed matter-antimatter asymmetry. In particular, the future colliders will provide an order of magnitude improvement in sensitivity to anomalous CP-violating interactions induced by dimension-six effective field theory operators when compared to the high-luminosity LHC programme.

    hep-phhep-exPRD(2026)·1 citation
12. 12*

    Evading the BBN bound with a soft stiff period

    Lucy Brissenden🇬🇧 · Konstantinos Dimopoulos🇬🇧 · Eemeli Tomberg🇪🇪

    Cosmic inflation is the leading theory to explain early Universe history and structure formation. Non-oscillatory inflation is a class of models which can naturally introduce a post-inflationary stiff period of the Universe's evolution which boosts the signal of primordial gravitational waves (GWs), making it possible to observe them in forthcoming GW experiments. However, this pushes the GW energy density high enough to destabilise the process of Big Bang Nucleosynthesis (BBN). This problem can be overcome by "softening" the stiff period, so that the field is gradually tending towards freefall from a frozen start. Here, we consider a modified hybrid inflation model where the stiff period is driven by the waterfall field, allowing the barotropic parameter of the Universe to vary, so that it does not violate the BBN constraint but produces a characteristic gravitational wave spectrum soon to be observable.

    hep-phastro-ph.COgr-qchep-thJCAP(2026)·0 citations
13. 13*

    Charming top interactions with a neutral Higgs Boson decaying into ${\tau }^{+}{\tau }^{-}$ at the LHC

    Chenyu Fang🇺🇸 · Phillip Gutierrez🇺🇸 · Chung Kao🇺🇸

    We investigate the discovery potential of flavor changing neutral Higgs (FCNH) interactions in top quark decays at the LHC. A general two Higgs doublet model (2HDM) is adopted to study the top quark decay $t\to c{\varphi }^0$, where ${\varphi }^0$ is either a CP-even heavy neutral scalar ($H^0$), or a CP-odd pseudoscalar ($A^0$), followed by the Higgs boson decaying into ${\tau }^{+}{\tau }^{-}$. The complete process is $pp\to t\bar{t}\to tc{\varphi }^0\to (bjj)(c{\tau }_{lep}{\tau }_{had})+X$, where $t$ or $\bar{t}$ become virtual when $m_{\varphi }>m_t-m_c$, ${\tau }_{lep}$ and ${\tau }_{had}$ represent the $\tau$ leptonic decay (${\tau }^{\pm }\to {\ell }^{\pm }$ + MET) and the $\tau$ hadronic decay (${\tau }^{\pm }\to j_{\tau }$ + MET), respectively. We evaluate the cross section applying realistic selection criteria for the FCNH signal and the dominant physics background at the parton-level. In addition, we employ \textsc{MadGraph}, \textsc{Pythia}~8, and \textsc{Delphes} to perform a realistic event-level Monte Carlo simulation analysis. The collinear approximation is applied since the $\tau$'s from Higgs boson decays are highly boosted such that ${\tau }_{lep}$ and ${\tau }_{had}$ momenta are approximately in the same direction as the $\tau$'s, which enables the reconstruction of the Higgs boson mass. The energy of the charm quark provides an additional kinematic variable that discriminates the signal from the background. In the alignment limit, the FCNH couplings for the heavy Higgs bosons ($H^0$ and $A^0$) will not be suppressed [${\lambda }_{tcH}\propto \sin (\beta -\alpha )\approx 1$]. We study the discovery potential for the heavy neutral Higgs bosons at the LHC with collider energies of $\sqrt{s}=13$ TeV, 13.6 TeV and 14 TeV, and find the High-Luminosity LHC offers great promise for the discovery of heavier Higgs bosons from $t\to c{\varphi }^0$ or $t^{\ast }\to c{\varphi }^0$.

    hep-ph0 citations
14. 14*

    Metastable Strings and Gravitational Waves in One-Scale Models

    James Ingoldby🇬🇧 · Valentin V. Khoze🇬🇧 · Jessica Turner🇬🇧

    Metastable cosmic strings provide a minimal and predictive origin for the stochastic gravitational-wave background reported by Pulsar Timing Array experiments. We analyse this possibility in electroweak-like dark sectors with a single-stage breaking $SU(2)\times U(1)\to U(1)$ driven by one Higgs field. In the regime with dark sector Higgs mass below the $Z^{\prime }$ mass, and for sufficiently small $W^{\prime }$ mass, the resulting $Z$-string is classically stable but undergoes quantum decay via nucleation of monopole--antimonopole pairs along the string. We compute the corresponding semiclassical bounce action in a thin-defect approximation, treating both the string core and the monopole endpoints as localised defects whose sizes are small relative to their separation in the tunnelling configuration. This yields a decay rate per unit length that depends on the gauge couplings and the mass hierarchy. We delineate the parameter space in which single-scale dark-sector models reproduce the PTA signal, demonstrating the applicability of the thin-defect approximation throughout the phenomenologically favoured region and without invoking extended Higgs sectors or multi-stage symmetry breaking.

    hep-phastro-ph.COhep-thJHEP(2026)·5 citations
15. 15*

    Hunting for Neutrino Texture Zeros with Muon and Tau Flavor Violation

    Lorenzo Calibbi🇨🇳 · Xiyuan Gao🇩🇪 · Man Yuan🇨🇳

    We revisit the minimal type II seesaw mechanism generating the Majorana neutrino mass matrix $M^{\nu }$, under the assumption that two entries of $M^{\nu }$ vanish. Such flavor structures are known as two-zero textures. Processes with charged lepton flavor violation (CLFV), absent in the Standard Model (SM), can have sizable rates in this framework and are directly linked to the flavor structure of $M^{\nu }$. For each allowed two-zero texture, we quantify the predicted correlations among various CLFV observables using current neutrino oscillation data and show that they lead to distinctive patterns of CLFV processes that could be discriminated between at running and upcoming experiments. In addition, together with information from colliders, the sensitivity of these correlations to renormalization group (RG) effects could shed light on the potentially ultra-high scale where new dynamics (e.g. some underlying flavor symmetry) give rise to the two-zero texture. Furthermore, we find that certain zero textures, although not third-generation specific, can suppress $\mu \to e$ transitions while allowing the rate of the process $\tau \to \bar{\mu }ee$ to be within the future experimental sensitivity, even when the RG evolution is taken into account. The lowest possible cut-off scale of the effective theory, constructed by treating the two-zero flavor structure of $M^{\nu }$ as a CLFV spurion, can therefore reach $5-6$ TeV. Our results provide further motivation for searches for $\tau$ CLFV at Belle II, as probes of new physics complementary to MEG II and the upcoming Mu3e, COMET, and Mu2e experiments, as well as for collider searches for doubly charged scalar bosons.

    hep-phhep-exJHEP(2026)·4 citations
16. 16*

    Isospin-breaking in the $\pi \pi$ scattering amplitude I: Effects due to the pion mass difference

    Gilberto Colangelo🇨🇭 · Martina Cottini🇨🇭 · Jacobo Ruiz de Elvira🇪🇸

    This is the first of a series of papers devoted to a detailed analysis of isospin-breaking effects in the $\pi \pi$ scattering amplitude and the vector form factor of the pion. Isospin breaking originates from the mass difference between up and down quarks and from electromagnetic effects. The latter can be further split into effects due to the pion-mass difference and the remaining virtual and real photonic effects. In this paper, we derive the modifications to the Roy equations for $\pi \pi$ scattering due to the mass difference between the charged and the neutral pion. We solve the equations numerically after matching them to the chiral representation of the $\pi \pi$ scattering amplitude evaluated in the same approximation, which is also provided. Numerical results are presented and discussed in detail.

    hep-phhep-exhep-latnucl-thJHEP(2026)·7 citations
17. 17*

    Hadronic CP Violation in the 2HDM

    Wolfgang Altmannshofer🇺🇸 · Joachim Brod🇺🇸 · Patipan Uttayarat🇹🇭 · Daniil Volkov🇺🇸

    We present the first complete two-loop calculation of the electric and chromo-electric dipole moments of the light quarks and the gluon, as well as contributions to CP-violating lepton-quark interactions, in the unconstrained two-Higgs doublet model. We include the most general Yukawa interactions of the Higgs doublets with the Standard Model fermions up to quadratic order, and allow for generic phases in the Higgs potential. We pay particular attention to a consistent treatment of all fermionic contributions in the low-energy effective theory, including a consistent renormalization-group summation of all leading-logarithmic effects. This latter part of the work is independent of the specific UV model and can generally be applied to a large class of models that do not introduce new light degrees of freedom. A python implementation of our results is provided via a public git repository.

    hep-phJHEP(2026)·2 citations
18. 18*

    Global Determination of $|V_{us}|$

    Matthew Kirk🇬🇧 · Danny van Dyk🇬🇧

    In light of ongoing issues with the first-row unitarity test of the CKM matrix, we showcase a global fit to measurements of $K\to \ell \nu$, $K\to \pi \ell \nu$, $\tau \to K\nu$, and $\tau \to K\pi \nu$ decays for the first time. Fitting the semileptonic and 3-body $\tau$ decay data simultaneously becomes computationally feasible because we employ a simple form factor parametrisation for the $K\pi$ form factor that manifestly connects the semileptonic and pair-production regions. We find good agreement with the data and use our analyses to infer $|V_{us}|$ and the parameters for the $K\pi$ form factors. Our result for $|V_{us}|$ sits close to the results extracted from exclusive $K_{\ell 2}$ and somewhat above the $K_{\ell 3}$ decay and inclusive $\tau$ decay result. Moreover, our results for the $K\to \pi$ vector form factor at zero momentum transfer are compatible with lattice QCD determinations, despite not using lattice QCD inputs for this quantity in our fit of the hadronic matrix elements. We are further able to determine some of the pole parameters of the individual scalar and vector $K\pi$ resonances with masses below the $\tau$ mass. We caution that our results account only for short-distance electromagnetic corrections but not long-distance contributions; this is due to the lack of a consistent description of long-distance corrections to the $K\pi$ matrix elements both above and below threshold for an arbitrary model of the form factors.

    hep-phPRD(2026)·1 citation
19. 19*

    Quantum Spacetime Imprints: The 24-Cell, Standard Model Symmetry and Its Flavor Mixing

    Ahmed Farag Ali🇺🇸

    In our previous work \cite{FaragAli:2024jpo} we outlined an exploratory framework in which the 24-cell acts both as the quantum of spacetime and as a geometric representation of elementary particles. In this paper we provide comprehensive mathematical and phenomenological evidence that deepens and refines this primary model. The symmetry of the 24-cell yields a unified hypercharge functional that reproduces Standard Model hypercharge assignments while ensuring anomaly cancellation. By projecting the vertices of the 24-cell onto a three-dimensional flavor subspace using a Minimal Distortion Principle, an emergent tetrahedral structure appears that gives rise to an effective $A_4$ symmetry in the neutrino sector. Extending this discrete symmetry to its binary double cover $T^{\prime }$ provides the spinorial representations and intrinsic complex phases needed to generate realistic quark Yukawa textures. Guided by the tenet that spacetime and matter are inextricably linked, our analysis suggests that the intricate flavor mixing of the Standard Model may be a residual imprint of the underlying quantum-geometric nature of spacetime.

    hep-phhep-thEPJC(2025)·0 citations
20. 20*

    On the role of induced electric field in the time-dependent Aharonov-Bohm effect

    Masashi Wakamatsu🇯🇵

    Whether the time-dependent Aharonov-Bohm (AB) effect even exists or not has been the subject of long-standing debate. There are two factors complicating the problem. First, in the closed spacetime line integral of the vector potential that is thought to give the AB-phase shift, how to treat the time-varying vector potential is highly nontrivial. Second, the time-varying magnetic flux generates induced electric field even outside the solenoid. In the present paper, motivated by a recent work by Gao, we re-investigate the role of the induced electric field with the utmost care. This analysis reveals a highly nontrivial effect of the induced electric field, which turns out to be useful for verifying the very existence of the time-dependent AB-effect.

    ↳ quant-phhep-phnucl-th0 citations
21. 21*

    Detecting Parity-Violating Gravitational Wave Backgrounds with Pulsar Polarization Arrays

    Qiuyue Liang🇯🇵 · Kimihiro Nomura🇯🇵 · Hidetoshi Omiya🇯🇵

    Pulsar timing arrays probe isotropic stochastic gravitational wave (GW) backgrounds in the nanohertz band but are insensitive to its parity-violating component. Motivated by recent progress in pulsar polarization arrays, we study the response of pulsar polarimetry to GWs and evaluate its potential to detect circular polarization in isotropic stochastic GW backgrounds, which characterizes parity violation. Based on geometric optics, we derive the rotation of the polarization of electromagnetic waves induced by propagation through a GW background. We show that the cross-correlation between pulsar timing and polarimetry signals isolates the circular polarization component from the GW intensity, sharing the same Hellings-Downs angular pattern. With future facilities such as the SKA, timing-polarimetry correlations could reach sensitivities to the circular polarization of GWs comparable to those of the current astrometric methods.

    ↳ gr-qcastro-ph.COhep-phPRD(2026)·4 citations
22. 22*

    Exact Results for the Spectrum of the Ising Conformal Field Theory

    Oleg Antipin🇭🇷 · Jahmall Bersini🇨🇭 · Jacob Hafjall🇩🇰 · Giulia Muco🇩🇰 · Francesco Sannino🇩🇰

    We develop a semiclassical framework to determine scaling dimensions of neutral composite operators in scalar conformal field theories. For the critical Ising $\lambda {\varphi }^4$ theory in $d=4-ϵ$, we obtain the full spectrum of composite operators built out of $n$ fields transforming in the traceless-symmetric Lorentz representations to next-to-leading order in the double-scaling limit $n\to \infty$ and $\lambda \to 0$ with $\lambda n$ fixed. At any given order the semiclassical expansion resums an infinite number of Feynman diagrams. Combining our results with existing perturbative computations further yields the complete five-loop scaling dimensions in the $ϵ$-expansion for the family of ${\varphi }^n$ operators. Finally, in three dimensions the next-to-leading order semiclassical results supersede any other existing methodology for $n\gtrsim \mathcal{O}(10)$.

    ↳ hep-thcond-mat.str-elhep-ph5 citations
23. 23*

    Anomaly induced transport from symmetry breaking in holography

    Ashis Tamang🇮🇳 · Nishal Rai🇮🇳 · Karl Landsteiner🇪🇸 · Eugenio Megias🇪🇸

    We study the transport properties of relativistic fluids induced by quantum anomalies in presence of explicit symmetry breaking. To this end we consider a holographic Einstein-Maxwell model in 5 dimensions with pure gauge and a mixed gauge-gravitational Chern-Simons terms, coupled with a scalar field. To study the chiral vortical effects and the energy transport sector, apart from the chiral magnetic effects, we have considered the full backreaction of the gauge field on the metric. We have studied the anomalous effects by using Kubo formulae involving correlators of the charged currents and the energy current. Our findings reveal that, in the presence of explicit symmetry breaking, anomaly-induced transport phenomena can extend beyond anomalous currents and affect non-anomalous sectors as well. In particular, we find that all the conductivities display a distinct sensitivity to the mass parameter controlling the symmetry breaking, thus reflecting the interplay between anomaly coefficients and explicit symmetry breaking terms. These findings highlight the role played by pure gauge and mixed gauge-gravitational anomalies in holographic transport, and their importance for strongly coupled systems with broken symmetries.

    ↳ hep-thcond-mat.str-elhep-phnucl-thJHEP(2026)·1 citation
24. 24*

    Revisiting the Possibility of a Sharp Phase Transition in Cold Neutron Stars

    Bao-Jun Cai🇨🇳 · Bao-An Li🇺🇸 · Yu-Gang Ma🇨🇳

    First-order phase transitions (FOPTs) in cold neutron stars (NSs) have been extensively studied and have provided valuable insights into the behavior of the densest matter visible in our Universe, although a strong consensus has yet to emerge. Revisiting the possibility of a hadron-quark FOPT from a new perspective, we examine the interplay between the coupled nature of gravity and microscopic interactions in Tolman--Oppenheimer--Volkoff (TOV) equations and the fundamental requirements of thermodynamic consistency in NSs. We demonstrate that a sharp FOPT manifested as a plateau in the equation of state (EOS) $P(\epsilon )$, i.e., pressure $P$ versus energy density $\epsilon$, is intrinsically incompatible with the regularity conditions of the TOV solutions. Although numerical integrations of the TOV equations with EOSs incorporating FOPTs may yield seemingly reasonable mass-radius relations consistent with current observations, such results can mask underlying inconsistencies. Our analysis thus establishes a structural consistency criterion for constraining dense-matter EOSs using NS observables, complementing existing studies of possible phase transitions in NS interiors.

    ↳ astro-ph.HEhep-phhep-thnucl-ex+10 citations
25. 25*

    Bounds on screened dark energy from near-Earth space-based measurements

    Fabiano Feleppa🇮🇹 · Welmoed Marit de Graaf🇮🇹 · Philippe Brax🇫🇷 · Gaetano Lambiase🇮🇹

    We test screened dark energy with near-Earth, space-based measurements. In a post-Newtonian framework, we compute leading corrections to geodetic precession (Gravity Probe B), LAGEOS-2 pericenter advance, and the Sagnac delay in a prospective orbital configuration, yielding bounds on chameleon, symmetron, and dilaton models. LAGEOS-2 sets the strongest Earth-orbit limits on symmetron and dilaton, while a Sagnac setup at the projected sensitivity of state-of-the-art space clocks gives the tightest chameleon constraint. These results show that low-density, space-based experiments sensitively probe screened dark energy and exclude previously allowed parameter space. Notably, at nuclear-clock precision $\mathcal{O}\left(10^{-19}\right)$, a Sagnac test would exclude the entire chameleon parameter space considered.

    ↳ gr-qcastro-ph.COhep-phPRL(2026)·7 citations
26. 26*

    Nonlinear Gravitational Wave Memory : Universal Low-Frequency Background

    Caner Ünal🇹🇷 · Doğa Veske🇹🇷

    A universal contribution exists in the infrared (low frequency) regime of all gravitational waves, which results from nonlinear memory. Nonlinear memory is sourced by linear order gravitational waves and exists for any gravitational-wave background. We calculate the stochastic nonlinear memory signal of various stochastic backgrounds of cosmological (scalar induced, reheating, phase transition, topological defect, turbulence) and astrophysical (binary mergers of stellar-mass, intermediate mass, supermassive, and primordial black holes) origins. These results allow us to derive the complete frequency spectrum of cosmological and astrophysical SGWB. We calculate how to probe the thermal state of the universe, i.e. the equation of the state, via the memory spectrum's slope and also discuss the detection prospects at various frequency bands with future experiments.

    ↳ gr-qcastro-ph.COastro-ph.HEhep-ph+14 citations
27. 27*

    QCD String Axions and $M$-theory

    Bobby Samir Acharya🇮🇹 · Ethan Torres🇨🇭

    In $SU(N)$ Yang-Mills theory without matter, there exist stable long electric fluxtube strings which carry a 1-form symmetry charge. Over the past decade or so, there has been increasing evidence from lattice calculations that the worldsheet theories of such QCD strings contain a massive pseudoscalar (axion), at least when $N\ge 3$. This has so far been puzzling from the perspective of holographic realizations of strings in confining gauge theories. In this note, we will show how such axions appear naturally in the realization of 4D $\mathcal{N}=1$ Super-Yang-Mills (SYM) from $M$-theory spacetimes in which the extra dimensions are modeled by certain complete metrics of $G_2$-holonomy. This picture predicts that QCD string axions exist only if the gauge group is $SU(N\ge 3)$, $SO(4N+2)$, or $E_6$ (or a quotient/double-cover thereof), and is absent from the spectrum of stable QCD strings if the gauge group is $SU(2)$, $SO(2N+1)$, $SO(4N)$, $Sp(N)$, or $E_7$. We argue why we expect this pattern to persist for non-supersymmetric Yang-Mills strings, at least for large $N$, something which could be tested in future lattice studies of QCD strings for gauge algebras of B, C, D, and E-type.

    ↳ hep-thhep-lathep-ph1 citation
28. 28*

    Dark winds on the horizon: Prospects for detecting neutrino and hot dark matter wakes in large-scale structure

    Caio B. de S. Nascimento🇺🇸 · Marilena Loverde🇺🇸

    We explore the cosmological signatures of neutrino and Hot Dark Matter (HDM) wakes, which refers to the preferential accumulation of neutrinos (or, more broadly, HDM particles) downstream of moving cold dark matter structures. We improve on existing theoretical models, and provide forecasts for the detectability of the effect in future surveys under more realistic conditions than previously considered in the literature. We show that neutrino and HDM wakes are unlikely to be ever observed with the most natural tracer of a hot subcomponent of the total dark matter on cosmological scales, i.e. 2D weak lensing surveys. However, the effect can be detected at a high significance with idealistic 3D maps of a tracer of HDM, for sufficiently small values of the effective free-streaming length (e.g. present-day values of $k_{\text{fs},0}\gtrsim 0.1{\text{Mpc}}^{-1}$ to reach $\text{SNR}\gtrsim 1$, for a HDM species accounting for a percent of the total dark matter). HDM wakes are a smoking gun of the effects of free-streaming, which cannot be mimicked by changes to the background expansion history (such as allowing for the dark energy to be dynamical), and hence offer another avenue to search for massive neutrinos, and hot subcomponents of the total dark matter more broadly, in a way that complements traditional observables.

    ↳ astro-ph.COhep-phJCAP(2026)·1 citation
29. 29*

    Early Formation of Supermassive Black Holes via Dark Star Gravitational Instability

    Katherine Freese🇺🇸 · George M. Fuller🇺🇸 · Sohan Ghodla🇺🇸 · Cosmin Ilie🇺🇸 · Kyle S. Kehrer🇺🇸 · Tanja Rindler-Daller🇦🇹 · Evangelos I. Sfakianakis🇺🇸

    We show that dark stars, which are dark-matter-powered stars in the early universe, can grow by accretion to masses in the range $\mathcal{O}\left({10}^4\right)-\mathcal{O}\left({10}^7\right)M_{\odot }$ before the general-relativistic Feynman-Chandrasekhar instability causes their dynamical collapse to black holes. These accreting dark star configurations avoid standard stellar nuclear- and weak-interaction evolution that would lead to their demise long before they reached this supermassive size. Remarkably, this mechanism for supermassive black hole (SMBH) genesis is relatively robust to initial dark star mass, formation epoch, accretion rate and its history. The SMBHs produced this way can serve as seeds for even larger SMBHs $(\gtrsim 10^9{M}_{\odot })$ that have been discovered at high redshift.

    ↳ astro-ph.COgr-qchep-ph7 citations
30. 30*

    Analytical solution and Lie algebra of the relativistic Boltzmann equation

    Yi Wang🇨🇳 · Xuan Zhao🇨🇳 · Zhe Xu🇺🇸 · Jin Hu🇨🇳

    In this work, we present a novel and more efficient approach to constructing the relativistic Bobylev, Krook, and Wu (BKW) solution [A. V. Bobylev, Sov. Phys. Dokl. 20, 820 (1976); M. Krook and T. T. Wu, Phys. Fluids 20, 1589 (1977)] of the relativistic Boltzmann equation. Introducing a new ansatz for the distribution function, we demonstrate that within this specific ansatz space, only the equilibrium and BKW-type forms yield exact solutions to the nonlinear Boltzmann equation. Furthermore, we also derive the Lie algebra of invariant transformations admitted by the relativistic Boltzmann equation and show that the corresponding symmetry group transformations can be systematically constructed from this algebra.

    ↳ nucl-thcond-mat.stat-mechhep-phhep-thPRD(2026)·2 citations
31. 31*

    Path integral predictions for pre-asymptotic false vacuum decay

    Joshua Lin🇺🇸 · Bruno Scheihing-Hitschfeld🇺🇸 · Thomas Steingasser🇺🇸

    When tunneling occurs out of generic initial states, a significant fraction of probability is lost at early times during which the dynamics is governed by excited resonance states. However, first-principles analyses based on path integrals have only captured the leading asymptotic behavior during which the tunneling rate is dominated by the false vacuum contribution. In this work, we discuss the behavior in the pre-asymptotic regime from a first-principles path integral perspective. We demonstrate how the relevant expressions can be evaluated systematically through semi-classical methods in the recently developed steadyon picture. This approach allows one to trace the role of the relevant physical scales, making transparent the underlying assumptions and approximations and offering a clear path to establishing a systematically improvable framework to evaluate tunneling rates non-perturbatively.

    ↳ hep-thhep-phquant-phPRD(2026)·7 citations
32. 32*

    Quantum tunneling from excited states in the steadyon picture

    Joshua Lin🇺🇸 · Bruno Scheihing-Hitschfeld🇺🇸 · Thomas Steingasser🇪🇸

    Recent developments in the understanding of real-time path integrals led to the development of the ``steadyon picture'' for the semi-classical calculation of quantum tunneling rates. We discuss tunneling out of a generic localized initial state in this picture and present its application for the important example of a resonance state in a one-dimensional point particle potential. We find that the steadyon picture indeed reproduces existing results obtained using the WKB method. Our analysis furthermore demonstrates how applying this picture to physical states naturally addresses open conceptual questions regarding this framework. Finally, we perform a numerical study for a specific potential. We demonstrate in particular the existence of regimes in which the tunneling rate is dominated by higher resonances, rather than the false vacuum, as well as their importance.

    ↳ hep-thhep-phquant-ph6 citations
33. 33*

    Massive Inflationary Amplitudes: New Representations and Degenerate Limits

    Zhong-Zhi Xianyu🇨🇳 · Jiaju Zang🇨🇳

    The particle model building of cosmological collider physics often involves boost-breaking bilinear mixing between a heavy particle and the nearly massless inflaton mode. In cosmological correlators, such a mixing is obtained by taking a folded limit of a generic tree graph, which is a special case of degenerate kinematics. In this work, we continue our exploration of massive inflationary amplitudes with a focus on degenerate kinematics. With a suitable change of variables, we derive new differential equations and full analytical solutions for generic tree graphs, making it trivial to take the folded limit and partial-energy limit at a vertex. Our result shows that folded tree graphs generally involve functions of smaller transcendental weights than their nondegenerate counterparts. In particular, the inflaton bispectrum with triple massive exchanges can be expressed in terms of a trivariate Kampé de Fériet function and simpler hypergeometric functions.

    ↳ hep-thastro-ph.COhep-phJHEP(2026)·16 citations
34. 34*

    Excitation factors for horizonless compact objects: long-lived modes, echoes, and greybody factors

    Romeo Felice Rosato🇮🇹 · Shauvik Biswas🇮🇳 · Sumanta Chakraborty🇮🇳 · Paolo Pani🇮🇹

    We present an analytical and numerical investigation of the quasinormal excitation factors of ultracompact horizonless objects. These systems possess long lived quasinormal modes with extremely small imaginary parts, originating from the effective cavity between the photon sphere and the object's interior. We show that the excitation of such modes is strongly suppressed, scaling with the imaginary part of their frequency, and therefore they contribute to the waveform only at very late times. This hierarchy naturally explains the structure of echo signals: the prompt ringdown is dominated by standard light ring modes, the early echoes arise from moderately damped cavity modes, and only the latest echoes are governed by long lived modes. Based on this, we propose a practical ringdown waveform model based on a superposition of ordinary black hole quasinormal modes and cavity modes, which captures the complexity of the ringdown of horizonless ultracompact objects. We further demonstrate that the combination of small excitation factors and weak damping enhances the robustness of long lived modes against localized perturbations, in contrast to the spectral instabilities affecting standard black hole quasinormal modes. Finally, we extend the analysis of greybody factors to exotic compact objects and wormholes, showing that they remain stable under small deformations of the effective potential and thus represent robust observables. Our results provide a unified framework for understanding excitation, stability, and echoes in ultracompact horizonless objects, with direct implications for their spectral properties and gravitational wave signatures.

    ↳ gr-qcastro-ph.HEhep-phPRD(2026)·11 citations
35. 35*

    The Light Dark Matter eXperiment

    Tamas Almos Vami (for the LDMX Collaboration)

    Searching for dark matter (DM) at colliders is one of the biggest challenges in high-energy physics today. Significant efforts have been made to detect DM within the mass range of 1-10,000 GeV at the Large Hadron Collider and other experiments. However, the lower mass range of 0.001-1 GeV remains largely unexplored, despite strong theoretical motivation from thermal dark matter models in that mass range. The Light Dark Matter eXperiment (LDMX) is a proposed fixed-target experiment at SLAC's LCLS-II 8 GeV electron beamline, specifically designed for the direct production of sub-GeV dark matter. The experiment operates on the principle of detecting missing momentum and missing energy signatures. In this talk, we will present the experimental design of LDMX detector and discuss strategies for detecting dark matter. The talk will detail traditional discriminants-based methods using the electromagnetic and hadronic calorimeters as a veto for Standard Model processes. Additionally, the application of advanced machine learning techniques, such as boosted decision trees and graph neural networks, for distinguishing signal from background will be discussed.

    ↳ hep-exhep-phPHEP(2026)·0 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.