Wed·Apr 2, 2025Wednesday·April 2, 2025

1. 01*

   Mapping between ${\gamma }_5$ schemes in the Standard Model Effective Field Theory

   S. Di Noi🇩🇪 · R. Gröber🇮🇹 · P. Olgoso🇮🇹

   We explore the relation between two distinct prescriptions for ${\gamma }_5$ in dimensional regularization -- the Breitenlohner Maison t'Hooft Veltman (BMHV) scheme and Naive Dimensional Regularisation (NDR). The BMHV scheme is the only algebraically consistent scheme, but necessitates chiral symmetry restoring counterterms and it is computationally more expensive, limiting its practical use. We show how the quantum effective action can be translated between both schemes and present these translation rules for the Wilson Coefficients of the Standard Model Effective Field Theory (SMEFT), that can easily be implemented into automated tools for SMEFT computations. Finally, we examine how this scheme dependence manifests itself in matching calculations, identifying the cases in which the dependence cancels in the final result. To examplify this, we consider a concrete UV scenario matched onto the SMEFT at one-loop order in both schemes. Our work aims to facilitate more accurate SMEFT computations and can be considered as a first step towards a comprehensive map between the two continuation schemes.

   hep-phJHEP(2025)·14 citations
2. 02*

   Monte Carlo phase space integration of multiparticle cross sections with carlomat_4.5

   Karol Kolodziej🇵🇱

   Multidimensional phase space integrals must be calculated in order to obtain predictions for total or differential cross sections, or to simulate unweighted events of multiparticle reactions. The corresponding matrix elements, already in the leading order, receive contributions typically from dozens of thousands of the Feynman diagrams, many of which often involve strong peaks due to denominators of some Feynman propagators approaching their minima. As the number of peaks exceeds by far the number of integration variables, such integrals can practically be performed within the multichannel Monte Carlo approach, with different phase space parameterizations, each designed to smooth possibly a few peaks at a time. This obviously requires a lot different phase space parameterizations which, if possible, should be generated and combined in a single multichannel Monte Carlo procedure in a fully automatic way.A few different approaches to the calculation of the multidimensional phase space integrals have been incorporated in version 4.5 of the multipurpose Monte Carlo program carlomat. The present work illustrates how carlomat_4.5 can facilitate the challenging task of calculating the multidimensional phase space integrals.

   hep-phComput.Phys.Commun.(2025)·0 citations
3. 03*

   Branching fractions and CP asymmetries in charm meson decays

   Ulrich Nierste🇩🇪

   I present a consistent way to include $\eta$-${\eta }^{\prime }$ mixing in global analyses of two-body decays of heavy hadrons employing the approximate flavour-SU(3) symmetry of QCD. The framework is applied to $D\to P{\eta }^{\prime }$ decays, where $P$ denotes a pseudoscalar meson. The result shows that flavour-SU(3) symmetry holds in the decay rates of these modes to better than 30%. With future data we expect the branching ratios of $D_s\to K^{+}{\eta }^{\prime }$ and $D\to K^{+}{\eta }^{\prime }$ to move upward and downward by $\sim 1\sigma$, respectively. Subsequently I discuss the implications of the LHCb measurements of the CP asymmetries in $D\to K^{+}{K}^{-}$ and $D\to {\pi }^{+}{\pi }^{-}$ for generic scenarios of new physics. New-physics contributions should have imprints on other CP asymmetries as well and can be tested through sum rules. Promising decays are $D_s^{+}\to K^0{\pi }^{+}$, $D^{+}\to {\bar{K}}^0{K}^{+}$, $D^0\to K^0{\bar{K}}^{\ast 0}$, $D^0\to {\bar{K}}^0{K}^{\ast 0}$, $D_s^{+}\to K^{\ast 0}{\pi }^{+}$, and $D^{+}\to {\bar{K}}^{\ast 0}{K}^{+}$.

   hep-phPoS(2025)·0 citations
4. 04*

   Supercooled Confinement

   Prateek Agrawal🇬🇧 · Gaurang Ramakant Kane🇬🇧 · Vazha Loladze🇬🇧 · Mario Reig🇬🇧

   We study general properties of confinement phase transitions in the early universe. An observable gravitational wave signal from such transitions requires significant supercooling. However, in almost all understood examples of confining gauge theories the degree of supercooling is too small to give interesting gravitational wave signals. We review and highlight the evidence why supercooling is not generic in confining gauge theories. The exceptions are Randall-Sundrum models which define a strongly coupled gauge theory holographically by a 5D gravitational theory. We construct a simple illustrative model of a 4D gauge theory inspired by features of the Randall-Sundrum model. It is a large-$N$ gauge theory in the conformal window coupled to a weakly coupled scalar field which undergoes a supercooled phase transition that breaks the conformal symmetry and triggers confinement. We show that there are interesting features in the gravitational wave spectra that can carry the imprint of the confining gauge theory.

   hep-phastro-ph.COhep-thJHEP(2025)·17 citations
5. 05*

   Reinterpretation and preservation of data and analyses in HEP

   Jon Butterworth🇬🇧 · Sabine Kraml🇫🇷 · Harrison Prosper🇺🇸 · Andy Buckley🇬🇧 · Louie Corpe🇫🇷 · Cristinel Diaconu🇫🇷 · Mark Goodsell🇫🇷 · Philippe Gras🇫🇷 · Martin Habedank🇬🇧 · Clemens Lange🇨🇭 · Kati Lassila-Perini🇫🇮 · André Lessa🇧🇷 and 136 other authors

   Data from particle physics experiments are unique and are often the result of a very large investment of resources. Given the potential scientific impact of these data, which goes far beyond the immediate priorities of the experimental collaborations that obtain them, it is imperative that the collaborations and the wider particle physics community publish and preserve sufficient information to ensure that this impact can be realised, now and into the future. The information to be published and preserved includes the algorithms, statistical information, simulations and the recorded data. This publication and preservation requires significant resources, and should be a strategic priority with commensurate planning and resource allocation from the earliest stages of future facilities and experiments.

   hep-phhep-ex4 citations
6. 06*

   ${}^3$H and ${}^3$He nuclei production in a combined thermal and coalescence framework for heavy-ion collisions in the few-GeV energy regime

   Zbigniew Drogosz🇵🇱 · Wojciech Florkowski🇵🇱 · Radoslaw Ryblewski🇵🇱 · Nikodem Witkowski🇵🇱

   A thermal model describing hadron production in heavy-ion collisions in the few-GeV energy regime is combined with the idea of nucleon coalescence to make predictions for the ${}^3$H and ${}^3$He nuclei production. A realistic parametrization of the freeze-out conditions is used, which reproduces well the spectra of protons and pions. It also correctly predicts the deuteron yield that agrees with the experimental value. The predicted yields of ${}^3$H and ${}^3$He appear to be smaller by about a factor of two compared to the experimental results. The model predictions for the spectra can be compared with future experimental data.

   hep-phnucl-thCPC(2026)·4 citations
7. 07*

   Atmospheric absorption of dark matter

   Man Ho Chan🇨🇳

   Typically, the interaction between dark matter and ordinary matter is assumed to be very small. Nevertheless, in this article, I show that the effective resonant absorption of dark photon dark matter in the atmosphere is definitely possible. This might also be associated with the alleged temperature anomalies observed in our upper stratosphere. By allowing a small amount of additional energy deposition to our upper stratosphere, a narrow dark matter mass range $m_A\sim 0.0001-0.001$ eV and the corresponding range of the mixing parameter $\epsilon$ are constrained for the first time. This proposal might overturn our usual assumption of extremely weak interaction between dark matter and ordinary matter and revive the hope of detecting dark matter directly. Some important implications of this proposal such as the heating of planets and supermassive dark stars would also be discussed.

   hep-phastro-ph.HEApJ(2025)·1 citation
8. 08*

   Almost general analysis of $\mu$-$\tau$ reflection symmetry perturbed by charged leptons and its testability by DUNE and T2HK

   Masaki J.S. Yang🇯🇵

   In this paper, we generally analyze the $\mu -\tau$ reflection symmetry modified by small mixings of charged leptons and how will future experiments verify deviations from the predictions of the symmetry. As an approximation, the left-handed diagonalization $U_e$ of charged leptons is assumed to have a similar magnitude as the CKM matrix. In other words, the 1-3 mixing is neglected and the 1-2 and 2-3 mixing are to be approximately $O(0.1)$. The Dirac CP phase $\delta$ of the MNS matrix is evaluated in such parameter regions. As a result, deviations from the predictions $\sin {\theta }_{23}=\pi /4$ and $\delta =\pm \pi /2$ depend on relative CP phases between $U_e$ and diagonalization of neutrinos $U_{\nu }$. While phases of the second and third generations cause only about $\pm 10^{\circ }$ deviations for the Dirac phase $\delta$, the phase of the first generation can cause up to $\pm 30^{\circ }$. This flavor dependence is distinguished to some extent by the next-generation experiments. On the other hand, if $\delta$ is not observed, such a scenario is excluded by about 5 years of observation.

   hep-phNPB(2025)·8 citations
9. 09*

   Resonant ALP-Portal Dark Matter Annihilation as a Solution to the $B^{\pm }\to K^{\pm }\nu \bar{\nu }$ Excess

   Kewen Ding🇨🇳 · Ying Li🇨🇳 · Xuewen Liu🇨🇳 · Yu Liu🇨🇳 · Chih-Ting Lu🇨🇳 · Bin Zhu🇨🇳

   The Belle II collaboration recently reported a $2.7\sigma$ excess in the rare decay $B^{\pm }\to K^{\pm }\nu \bar{\nu }$, potentially signaling new physics. We propose an axion-like particle (ALP)-portal dark matter (DM) framework to explain this anomaly while satisfying the observed DM relic abundance. By invoking a resonant annihilation mechanism ($m_a\sim 2m_{\chi }$), we demonstrate that the ALP-mediated interactions between the Standard Model and DM sectors simultaneously account for the $B^{\pm }\to K^{\pm }\nu \bar{\nu }$ anomaly and thermal freeze-out dynamics. Two distinct scenarios-long-lived ALPs decaying outside detectors (displaced diphotons) and ALPs decaying invisibly to DM pairs (missing energy)-are examined. While the displaced diphotons scenario is excluded by kaon decay bounds ($K^{\pm }\to {\pi }^{\pm }+\text{inv.}$), the invisible decay channel remains unconstrained and aligns with Belle II's missing energy signature. Using the coupled Boltzmann equation formalism, we rigorously incorporate early kinetic decoupling effects, revealing deviations up to a factor of 20 from traditional relic density predictions in resonance regions. For the missing energy scenario, the viable parameter space features ALP-SM and ALP-DM couplings: $g_{aWW}(g_{a\gamma \gamma })\in (7.13\times 10^{-5}-9.60\times 10^{-5}){\text{GeV}}^{-1}$ (from $B^{\pm }\to K^{\pm }a$) and $g_{a\chi \chi }\in (7.12\times 10^{-5}-7.73\times 10^{-3}){\text{GeV}}^{-1}$ (for resonant annihilation), accommodating ALP masses $m_a\in (0.6,4.8)\text{GeV}$. Therefore, this work establishes the ALP portal as a viable bridge between the $B^{\pm }\to K^{\pm }\nu \bar{\nu }$ anomaly and thermal DM production, emphasizing precision calculations of thermal decoupling in resonance regimes.

   hep-phPRD(2025)·13 citations
10. 10*

    Study of the subleading twist GTMD $E_{21}$ for proton in light-front quark-diquark model

    Sameer Jain🇮🇳 · Shubham Sharma🇷🇺 · Harleen Dahiya🇮🇳

    In this work, we study the generalized transverse momentum dependent distribution (GTMD) $E_{21}$ for proton using light-front quark-diquark model. We construct the expression of $E_{21}$ GTMD using the overlap equation in light-front wave functions obtained from the GTMD correlator with Dirac matrix structure $\Gamma =1$, in both situations of scalar and vector diquark. The $3$-dimensional plots of GTMD $E_{21}$ have been analyzed with respect to its variables by taking two variables at a time while holding others constant.

    hep-phPoS(2025)·0 citations
11. 11*

    Tensor Meson Pole contributions to the HLbL piece of $a_{\mu }$ within R$\chi$T

    Emilio J. Estrada🇲🇽 · Pablo Roig🇲🇽

    We compute the tensor meson pole contributions to the Hadronic Light-by-Light piece of $a_{\mu }$ in the purely hadronic region, using Resonance Chiral Theory. Given the differences between the dispersive and holographic groups determinations, we consider timely to present an alternative evaluation. In our approach, the lightest tensor meson nonet and two vector meson resonance nonets are considered in the chiral limit. Disregarding operators with derivatives, only the form factor ${\mathcal{F}}_1^T$ is non-vanishing, as assumed in the dispersive study. All parameters are determined by imposing a set of short-distance QCD constraints, and the radiative decay widths. In this case, we obtain (in units of $10^{-11}$): $a_2$-pole: $-\left(1.02(10{)}_{\mathrm{stat}}{(}_{-0.12}^{+0.00}{)}_{\mathrm{syst}}\right)$, $f_2$-pole: $-\left(3.2(3{)}_{\mathrm{stat}}{(}_{-0.4}^{+0.0}{)}_{\mathrm{syst}}\right)$ and $f_2^{\prime }$-pole: $-\left(0.042(13{)}_{\mathrm{stat}}\right)$, which add up to $a_{\mu }^{a_2+f_2+f_2^{\prime }-\mathrm{pole}}=-\left(4.3_{-0.5}^{+0.3}\right)$, in close agreement with the holographic result when truncated to ${\mathcal{F}}_1^T$ only. However, with an ad-hoc extended Lagrangian, that also generates ${\mathcal{F}}_3^T$, as in the holographic approach, we have found: $a_2$-pole: $+0.47(1.43{)}_{\mathrm{norm}}(3{)}_{\mathrm{stat}}{(}_{-0.00}^{+0.06}{)}_{\mathrm{syst}}$, $f_2$-pole: $+1.18(4.18{)}_{\mathrm{norm}}(12{)}_{\mathrm{stat}}{(}_{-0.00}^{+0.24}{)}_{\mathrm{syst}}$ and $f_2^{\prime }$-pole: $+0.040(78{)}_{\mathrm{norm}}(2{)}_{\mathrm{stat}}$, summing to $a_{\mu }^{a_2+f_2+f_2^{\prime }-\mathrm{pole}}=+1.7(4.4)$, which agree with these recent determinations within uncertainties (dominated by the ${\mathcal{F}}_3^T$ normalization). We point out that $R\chi T$ generates all form factors, the contributions to $a_{\mu }$ of ${\mathcal{F}}_{2,4,5}$ cannot be evaluated in the current basis, preventing for the moment a complete calculation of $a_{\mu }^{\mathrm{T}-\mathrm{poles}}$ within our framework.

    hep-phJHEP(2026)·10 citations
12. 12*

    General relativistic effects on photon spectrum emitted from dark matter halos around primordial black holes

    Toya Suzuki🇯🇵 · Takahisa Igata🇯🇵 · Kazunori Kohri🇯🇵 · Tomohiro Harada🇯🇵

    We investigate general relativistic effects on the photon spectrum emitted from decaying (or annihilating) particle dark matter in the halo surrounding a primordial black hole. The spectrum undergoes significant modification due to gravitational redshifts, which induces broadening as a result of the intense gravitational field near the black hole. This characteristic alteration in the photon spectrum presents a unique observational signature. Future observations of such spectral features may provide critical evidence for a mixed dark matter scenario, involving both primordial black holes and particle dark matter.

    hep-phastro-ph.COastro-ph.HEgr-qc+1PRD(2025)·1 citation
13. 13*

    Multiplicity distribution under the reflective scattering mode

    S.M. Troshin🇷🇺 · N.E. Tyurin🇷🇺

    Transition to the reflective scattering mode which has emerged at the highest LHC energy of $\sqrt{s}=13$ TeV results in a relative shrinkage with the energy of the impact parameter region responsible for the inelastic hadron collisions. Respective increasing role of the multiplicity fluctuations of quantum origin is emphasized.

    hep-phInt.J.Mod.Phys.A(2025)·2 citations
14. 14*

    Single spin asymmetry among hyperons using scalar diquark model

    Navpreet Kaur🇮🇳 · Harleen Dahiya🇮🇳

    The Fourier transformed chiral even generalized parton distributions $(GPDs)$ for purely transverse momentum transfer $({\Delta }^{+}=0)$ characterize an individual parton distribution of a hyperon in a perpendicular plane at some distance from the center of momentum of the system. Further, the presence of left-right asymmetry in the distorted parton distribution gives a clue for the presence of single-spin asymmetry. In order to have a deep insight into the distortions, we have exhibited the information about asymmetries from the spin flip matrix element of a $GPD$ for hyperons by employing scalar diquark model and also compared parton distributions of different possible combinations of quark-diquark pair to get substantial structural information on hyperons.

    hep-phPoS(2025)·0 citations
15. 15*

    The electron EDM in the decoupling limit of the aligned 2HDM

    Juan Manuel Dávila🇪🇸 · Anirban Karan🇪🇸 · Emilie Passemar🇺🇸 · Antonio Pich🇪🇸 · Luiz Vale Silva🇪🇸

    We discuss model-independent contributions to the electron EDM, focusing on those contributions emerging from a heavy scalar sector linearly realized. To provide a concrete new physics realization, we investigate the aligned 2HDM in the decoupling limit. We point out that logarithmically enhanced contributions generated from Barr-Zee diagrams with a fermion loop are present in the aligned 2HDM, an effect encoded in the decoupling limit by effective dimension-6 operators, through the mixing of four-fermion into dipole operators. The same large logarithms are absent in specific 2HDMs where a ${\mathcal{Z}}_2$ symmetry is enforced, which thus controls the basis of effective operators relevant for calculating new physics contributions to EDMs. In other words, the ${\mathcal{Z}}_2$ symmetry acts as a suppression mechanism. In the aligned 2HDM these contributions are proportional to sources of CP violation that are potentially large, and absent in presence of the ${\mathcal{Z}}_2$ symmetry. We then investigate the impact on the electron EDM of this extended set of free parameters.

    hep-phPoS(2025)·1 citation
16. 16*

    Lepton-proton two-photon exchange with improved soft-photon approximation including proton's structure effects in HB$\chi$PT

    Rakshanda Goswami🇮🇳 · Pulak Talukdar🇮🇳 · Bhoomika Das🇮🇳 · Udit Raha🇮🇳 · Fred Myhrer🇺🇸

    We present an improved evaluation of the two-photon exchange correction to the unpolarized lepton-proton elastic scattering process at very low-energies relevant to the MUSE experiment, where only the dominant intermediate elastic proton is considered. We employ the framework of heavy baryon chiral perturbation theory and invoke the soft-photon approximation in order to reduce the intricate 4-point loop-integrals into simpler 3-point loop-integrals. In the present work, we adopt a more robust methodology compared to an earlier work along the same lines for analytically evaluating the loop-integrations, and incorporate important corrections at next-to-next-to-leading order. These include the proton's structure effects which renormalize the proton-photon interaction vertices and the proton's propagator. Finally, our results allow a model-independent estimation of the charge asymmetry for the scattering of unpolarized massive leptons and anti-leptons.

    hep-phhep-thnucl-th0 citations
17. 17*

    Search for QCD coupled axion dark matter with the MICROSCOPE space experiment

    Jordan Gué🇪🇸 · Peter Wolf🇫🇷 · Aurélien Hees🇫🇷

    Axion dark matter coupled via QCD induces a non-zero differential acceleration between test masses of different composition. Tests of the equivalence principle, like the recent MICROSCOPE space mission, are sensitive to such a signal. We use the final released data of the MICROSCOPE experiment, to search for this effect. We find no positive signal consistent with the dark matter model, and set upper limits on the axion-gluon coupling that improve existing laboratory bounds by up to two orders of magnitude for axion masses in the $10^{-17}$ eV to $10^{-13}$ eV range.

    hep-phastro-ph.COgr-qchep-exPRL(2025)·17 citations
18. 18*

    Transverse spin polarization as a novel probe of medium-induced transverse-momentum-broadening effect

    Xin-yu Qin🇨🇳 · Yu-Kun Song🇨🇳 · Shu-yi Wei🇨🇳

    The transverse polarization of $\Lambda$ hyperons within unpolarized jets originates from the transverse-momentum-dependent (TMD) fragmentation function $D_{1T}^{\perp }(z,p_T,{\mu }^2)$. In the vacuum environment, the QCD evolution of this TMD fragmentation function is governed by the Collins-Soper equation. However, in the presence of the quark-gluon plasma (QGP) medium, the jet-medium interaction induces a transverse-momentum-broadening effect that modifies the QCD evolution. As a result, the transverse spin polarization of $\Lambda$ hyperons in relativistic heavy-ion collisions differs from that in $pp$ collisions. We demonstrate that this difference serves as a sensitive probe for studying jet-medium interaction, offering a novel perspective through the spin degree of freedom.

    hep-phhep-exnucl-exnucl-thPRD(2026)·3 citations
19. 19*

    Two-loop Renormalization Group Equations in the $\nu$SMEFT

    Di Zhang🇩🇪

    We calculate two-loop renormalization group equations (RGEs) in the Standard Model Effective Field Theory (SMEFT) with right-handed neutrinos, i.e., the so-called $\nu$SMEFT, up to dimension five. Besides the two-loop RGEs of dimension-five (dim-5) operators, we also present those of the renormalizable couplings, including contributions from dim-5 operators. We check consistency relations among the first and second poles of $\epsilon \equiv (4-d)/2$ with $d$ being the space-time dimension for all renormalization constants and find that those for lepton doublet and right-handed neutrino wave-function renormalization constants, as well as for renormalization constants of charged-lepton and neutrino Yukawa coupling matrices, do not hold. This leads to divergent RG functions for these fields and Yuwawa coupling matrices. We figure out that such infinite RG functions arise from the non-invariance of fields and Yukawa coupling matrices under field redefinitions, considering that flavor transformations are a kind of linear field redefinitions. Those infinite RG functions will disappear once one restores contributions from the derivative of renormalization constants with respect to the Wilson coefficients of redundant operators or, alternatively, considers the RGEs of flavor invariants, which are physical quantities and remain invariant under field redefinitions.

    hep-phhep-exJHEP(2025)·17 citations
20. 20*

    Topological Electroweak Phase Transition

    V.K. Oikonomou🇬🇷

    In this work we shall consider the effects of a non-trivial topology on the effective potential of the Standard Model. Specifically we shall assume that the spacetime topology is $S^1\times R^3$ and we shall calculate the Standard Model effective potential for such a topological spacetime. As we demonstrate, for small values of the compact dimension radius, the electroweak symmetry is unbroken, but for a critical length and beyond, the electroweak symmetry is broken, since the configuration space of the Higgs field contains an additional energetically favorable minimum, compared to the minimum at the origin. The two minima are separated by a barrier, thus a phase transition can occur, via quantum tunnelling, which mimics a first order phase transition. This is a non-thermal phase transition, similar possibly to quantum Hall topological phase transitions, hence in the context of this scenario, the electroweak symmetry breaking does not require a high temperature to occur. The present scenario does not rely on the occurrence of the inflationary era, only on the expansion of the Universe, however we briefly discuss the freezing of the superhorizon terms in $S^1\times R^3$ spacetime, if inflation occurred. We also investigate the large scale differences of the gravitational potential due to the non-trivial topology. Finally, we briefly mention the distinct inequivalent topological field configurations that can exist due to the non-trivial topology, which are classified by the first Stieffel class which in the case at hand is $H^1(S^1{\times R}^3,Z_{\tilde{2}})=Z_2$, so even and odd elements can exist. We also briefly qualitatively discuss how a topologically induced electroweak phase transition can yield primordial gravitational waves.

    hep-phastro-ph.COgr-qchep-thPhys.Dark Univ.(2025)·0 citations
21. 21*

    Diffusion-model approach to flavor models: A case study for $S_4^{\prime }$ modular flavor model

    Satsuki Nishimura🇯🇵 · Hajime Otsuka🇯🇵 · Haruki Uchiyama🇯🇵

    We propose a numerical method of searching for parameters with experimental constraints in generic flavor models by utilizing diffusion models, which are classified as a type of generative artificial intelligence (generative AI). As a specific example, we consider the $S_4^{\prime }$ modular flavor model and construct a neural network that reproduces quark masses, the CKM matrix, and the Jarlskog invariant by treating free parameters in the flavor model as generating targets. By generating new parameters with the trained network and local optimization, we find various phenomenologically interesting parameter regions. Additionally, we confirm that the spontaneous CP violation occurs in the $S_4^{\prime }$ model. The diffusion model enables an inverse problem approach, allowing the machine to provide a series of plausible model parameters from given experimental data.

    hep-phcs.LGhep-thPTEP(2026)·6 citations
22. 22*

    Model-independent unbinned analysis of $B\to K^{\ast }(\to K^{+}{\pi }^{-}){\mu }^{+}{\mu }^{-}$: zeroes, bounds, Wilson coefficients and symmetries

    Bernat Capdevila🇪🇸 · Joaquim Matias🇪🇸 · Martín Novoa-Brunet🇪🇸 · Mitesh Patel🇬🇧 · Mark Smith🇬🇧

    We present a model-independent method to study the four-body decay $B\to K^{\ast }(\to K^{+}{\pi }^{-}){\mu }^{+}{\mu }^{-}$, based on extracting continuous observables with a moments approach. The method allows the observables to be determined unbinned in both the dilepton and $K^{+}{\pi }^{-}$ invariant masses on which the decay dynamics depend. This will allow the method to shed new light on how the observables depend on the P- and S-wave contributions to the $K^{+}{\pi }^{-}$ system. This approach contrasts with the state-of-the-art analyses, which bin in dilepton and $K^{+}{\pi }^{-}$ mass, or use a model for the dependence of the underlying decay amplitudes on these masses. The method does not require making a statistical fit, and so avoids problems of biases and poor uncertainty estimation when dealing with small samples or a large number of fit parameters. We provide the Standard Model predictions for the unbinned optimised observables, derive new geometrical bounds on their values and study the robustness of these bounds in the presence of a scalar new physics contribution. We explore the zero-crossing points of $P_2$ and $P_{4,5}^{\prime }$ observables as a function of a new physics contribution to the dominant vector Wilson coefficient, $C_9^{\mathrm{NP}}$. We also discuss the conditions that can be used to test the theoretical model of the amplitudes needed for an experimental amplitude analysis. Finally, as an illustration, we show how the proposed method might be used to extract the zero-crossing points, make a comparison with the bounds and test a non-trivial relation between the observable values.

    hep-phhep-exPRD(2025)·5 citations
23. 23*

    Properties of the Object HESS J1731-347 as a Twin Compact Star

    David E. Alvarez-Castillo🇵🇱

    By consideration of the Compact object HESS J1731-347 as a hybrid twin compact star, i.e., a more compact star than its hadronic twin of the same mass, its stellar properties are derived. Besides showing that the properties of compact stars in this work are in good agreement with state-of-the-art constraints both from measurements carried out in laboratory experiments as well as by multi-messenger astronomy observations, the realization of an early strong hadron-quark first order phase transition as implied by the twins is discussed.

    ↳ astro-ph.HEastro-ph.SRhep-phnucl-thUniverse(2025)·6 citations
24. 24*

    The Short-Baseline Near Detector at Fermilab

    SBND Collaboration: R. Acciarri🇺🇸 · L. Aliaga-Soplin🇺🇸 · O. Alterkait🇺🇸 · R. Alvarez-Garrote🇪🇸 · D. Andrade Aldana🇺🇸 · C. Andreopoulos🇬🇧 · A. Antonakis🇺🇸 · L. Arellano🇬🇧 · W. Badgett🇺🇸 · S. Balasubramanian🇺🇸 · A. Barnard🇬🇧 · V. Basque🇺🇸 and 185 other authors

    SBND is a 112 ton liquid argon time projection chamber (LArTPC) neutrino detector located 110 meters from the Booster Neutrino Beam (BNB) target at Fermilab. Its main goals include searches for eV-scale sterile neutrinos as part of the Short-Baseline Neutrino (SBN) program, other searches for physics beyond the Standard Model, and precision studies of neutrino-argon interactions. In addition, SBND is providing a platform for LArTPC neutrino detector technology development and is an excellent training ground for the international group of scientists and engineers working towards the upcoming flagship Deep Underground Neutrino Experiment (DUNE). SBND began operation in July 2024, and started collecting stable neutrino beam data in December 2024 with an unprecedented rate of ~7,000 neutrino events per day. During its currently approved operation plans (2024-2027), SBND is expected to accumulate nearly 10 million neutrino interactions. The near detector dataset will be instrumental in testing the sterile neutrino hypothesis with unprecedented sensitivity in SBN and in probing signals of beyond the Standard Model physics. It will also be used to significantly advance our understanding of the physics of neutrino-argon interactions ahead of DUNE. After the planned accelerator restart at Fermilab (2029+), opportunities are being explored to operate SBND in antineutrino mode in order to address the scarcity of antineutrino-argon scattering data, or in a dedicated beam-dump mode to significantly enhance sensitivity to searches for new physics. SBND is an international effort, with approximately 40% of institutions from Europe, contributing to detector construction, commissioning, software development, and data analysis. Continued European involvement and leadership are essential during SBND's operations and analysis phase for both the success of SBND, SBN and its role leading up to DUNE.

    ↳ hep-exhep-phnucl-th24 citations
25. 25*

    Transition magnetic moments for $\Delta \to p$ transition in asymmetric nuclear matter

    Suneel Dutt🇮🇳 · Arvind Kumar🇮🇳 · Harleen Dahiya🇮🇳

    In the present work we calculate the transition magnetic moments for the radiative decays of $\Delta$ baryon to proton $(\Delta \to p)$ in isospin asymmetric nuclear medium at finite temperature using chiral SU(3) quark mean field model. Within the framework of chiral SU(3) mean field model, the properties of baryons in asymmetric medium are modified through the exchange of scalar fields $(\sigma ,\zeta ,\delta )$ and vector fields $(\omega ,\rho )$. The isospin asymmetry of medium is taken into account via scalar-isovector field $\delta$ and vector iso-vector field $\rho$. We calculate the in-medium masses of quarks, proton and $\Delta$ baryon in asymmetric matter within the chiral SU(3) quark mean field model and use these as input in the chiral constituent quark ($\chi$CQM) model to calculate the in-medium transition magnetic moments for $(\Delta \to p)$ transition for different values of isospin asymmetry of hot and dense medium. For calculating the magnetic moments of baryons, contributions of valence quarks, quark sea and orbital angular momentum of quark sea are considered in these calculations.

    ↳ nucl-thhep-phPoS(2025)·0 citations
26. 26*

    Physical Implications and Updated Observational Constraints of the PAge-like Unified Dark Fluid Model

    Yan Su🇨🇳 · Zhiqi Huang🇨🇳 · Yanhong Yao🇨🇳 · Junchao Wang🇨🇳 · Jianqi Liu🇨🇳

    The standard paradigm of cosmology assumes two distinct dark components, namely dark matter and dark energy. However, the necessity of splitting the dark-side world into two sectors has not been experimentally or theoretically proven. Unified dark fluid models provide an alternative in which a single fluid accounts for both phenomena. It is shown in Wang et al. 2024 that a PAge-like unified dark fluid (PUDF) can explain both the cosmic microwave background (CMB) and late-universe data, with the fitting quality not much worse than the standard Lambda cold dark matter ($\Lambda$CDM) model. Using the Planck 2018 CMB, baryon acoustic oscillations measurement from the dark energy spectroscopic instrument (DESI) data release 2, dark energy survey 5-year supernova data, and cosmic-chronometer data, we update the constraints on PUDF and clarify its physical implications. We show that PUDF can reproduce the primary CMB anisotropies, the background expansion history, and linear growth that are very close to the $\Lambda$CDM prediction. Nevertheless, the combined datasets still favor $\Lambda$CDM, largely due to the significant tension between CMB and DESI + SNe data, which exceeds the $4\sigma$ level in PUDF and remains non-negligible in the $w$CDM framework. Using mock data generated from the Planck best-fit $\Lambda$CDM model, we find that PUDF and $\Lambda$CDM cannot be statistically distinguished, indicating that the precision of current data is insufficient to separate the two models. Overall, the apparent preference for $\Lambda$CDM may be driven by dataset inconsistencies rather than a genuine physical difference, leaving unified dark fluid models as viable alternatives within current observational limits.

    ↳ astro-ph.COgr-qchep-phhep-thPLB(2026)·3 citations
27. 27*

    Illustrating the liquid gas transition of nuclear matter in QCD

    Fei Gao🇨🇳 · Yi Lu🇨🇳 · Si-xue Qin🇨🇳 · Zhan Bai🇨🇳 · Lei Chang🇨🇳 · Yu-xin Liu🇨🇳

    We demonstrate that the liquid-gas transition of nuclear matter can be rigorously described with the quantum chromodynamics by combining the quark gap equation and the Faddeev equation of nucleon. Our investigation focuses on this transition at zero temperature and finite chemical potential, revealing a finite difference between the gas and liquid solution of the quark propagator. This difference emerges from the shift of the nucleon pole mass in medium, which is generated in the nucleon channel of the quark gap equation. We prove that such a difference is precisely the contour contribution from the shift of the nucleon pole. The resulting discontinuity manifests as a first-order phase transition and fundamentally determines both the nuclear binding energy and the saturation density. We then derive an analytical relation between the binding energy and the sigma term of the nucleon, yielding a binding energy of $E/A=15.9\text{MeV}$. Furthermore, by establishing the relation between the nuclear saturation density and the vector charge of nucleon in association with the binding energy, we determine the saturation density to be $n_{\text{B}}^0=0.15{\text{fm}}^{-3}$.

    ↳ nucl-thhep-phhep-thnucl-exPRD(2025)·4 citations
28. 28*

    LEP3: A High-Luminosity e+e- Higgs and ElectroweakFactory in the LHC Tunnel

    C. Anastopoulos · R. Assmann · A. Ball · O. Bruning · O. Buchmueller · T. Camporesi · P. Collier · J Dainton · G. Davies · J.R. Ellis · B. Goddard · L. Gouskos and 16 other authors

    As stated in the 2019 European Strategy for Particle Physics (ESPP), it is of the utmost importance that the HL-LHC upgrade of the accelerator and the experiments be successfully completed in a timely manner. All necessary efforts should be devoted to achieving this goal. We also recall two of the principal recommendations of the 2019 ESPP for future accelerator initiatives, namely that 1) An electron-positron Higgs factory is the highest priority for the next collider (Rec. c). 2) Europe, together with its international partners, should investigate the technical and financial feasibility of a future hadron collider at CERN with a centre-of-mass energy of at least 100 TeV and with an electron-positron Higgs and electroweak factory as a possible first stage (Rec. e). A major objective in particle physics is always to operate an accelerator that allows a leap of an order of magnitude in the constituent centre-of-mass energy with respect to the previous one. We support FCC-ee and FCC-hh as the preferred option for CERN future, as it addresses both of the above recommendations. The guidance for the 2025 ESPP requests, in addition to the preferred option, the inclusion of ``prioritised alternatives to be pursued if the chosen preferred option turns out not to be feasible or competitive''. Proposed alternatives to the preferred FCC option include linear, muon colliders and LHeC accelerators. In response to this request we propose reusing the existing LHC tunnel for an electron-positron collider, called LEP3, as a back-up alternative if the FCC cannot proceed. LEP3 leverages much of the R\&D conducted for FCC-ee, offers high-precision studies of Z, W, and Higgs bosons below the tt threshold, and offers potential physics performance comparable or superior to other fallback options at a lower cost while supporting continued R\&D towards a next-generation energy frontier machine.

    ↳ physics.acc-phhep-exhep-phJ.Phys.G(2026)·18 citations
29. 29*

    Three-hadron dynamics from lattice QCD

    Fernando Romero-López🇨🇭

    Three-hadron spectroscopy is a key frontier in our understanding of the hadron spectrum. In recent years, significant formal and numerical advances have paved the way for studying three-hadron processes directly from lattice QCD, with outstanding applications including the Roper resonance and the doubly charmed tetraquark. This requires theoretical frameworks that relate finite-volume energies to infinite-volume three-particle scattering amplitudes. In this contribution, I discuss recent progress in formulating such frameworks for generic three-hadron systems, and present numerical results for three-meson systems at maximal isospin with physical quark masses, as well as our recent investigation of the three-body dynamics of the doubly charmed tetraquark, $T_{\mathrm{cc}}$.

    ↳ hep-lathep-phnucl-thPoS(2026)·4 citations
30. 30*

    Four-dimensional de Sitter cosmology on D-branes nucleated in an asymptotically ${\text{AdS}}_5\times T^{1,1}$ background

    Cao H. Nam🇻🇳

    We find four-dimensional de Sitter (dS) vacuum solutions on probe D-branes nucleating in a background, which is a U(1) charged black hole solution of IIB supergravity, including stringy corrections. A sufficiently high chemical potential induced by the wrapped D3-brane charge, inducing an instability in the system, is essential to lead to the nucleation of the probe D-branes. We show that stringy corrections can yield a dS vacuum on spherical D3-branes consistent with the observations without fine-tuning. Motivated by the fact that the matter fields propagating in the compact extra dimensions can provide solutions for problems in particle physics and cosmology, we also construct a dS vacuum on a probe D5-brane that wraps on a two-torus of the internal manifold $T^{1,1}$. This construction requires turning on a worldvolume U(1) gauge field along the wrapped part of the D5-brane and dissolving some D3-branes in the D5-brane. The stringy corrections play an important role in yielding a dS vacuum, and the field strength of the U(1) gauge field must be sufficiently large to produce a tiny cosmological constant.

    ↳ hep-thgr-qchep-ph0 citations
31. 31*

    A Novel Deep Learning Method for Detecting Nucleon-Nucleon Correlations

    Yu-Jing Huang🇨🇳 · Zhu Meng🇨🇳 · Long-Gang Pang🇨🇳 · Xin-Nian Wang🇨🇳

    This study investigates the impact of nucleon-nucleon correlations on heavy-ion collisions using the hadronic transport model SMASH in $\sqrt{s_{\mathrm{NN}}}=3$ GeV ${}^{197}\mathrm{Au}$+${}^{197}\mathrm{Au}$ collisions. We developed an innovative Monte Carlo sampling method that incorporates both single-nucleon distributions and nucleon-nucleon correlations. By comparing three initial nuclear configurations - a standard Woods-Saxon distribution (un-corr), hard-sphere repulsion (step corr), and ab initio nucleon-nucleon correlations (nn-corr)- we revealed minimal differences in traditional observables except for ultra-central collisions. When distinguishing between un-corr and nn-corr configurations, conventional attention-based point cloud networks and multi-event mixing classifiers failed (accuracy ~50%). To resolve this, we developed a novel deep learning architecture integrating multi-event statistics and high-dimensional latent space feature correlations, achieving 60\% overall classification accuracy, which improved to 70\% for central collisions. This method enables the extraction of subtle nuclear structure signals through statistical analysis in high-dimensional latent space, offering a new paradigm for studying initial-state nuclear properties and quark-gluon plasma characteristics in heavy-ion collisions. It overcomes the limitations of traditional single-event analysis in detecting subtle initial-state differences.

    ↳ nucl-thhep-phPRC(2026)·8 citations
32. 32*

    Universal critical behavior of generaliezd susceptibilities of net-baryon number at small quark mass

    Xue Pan🇨🇳 · Peng Yang🇨🇳 · Lingling Cao🇨🇳

    In the limit of small quark masses, the angle between the temperature axis and the applied magnetic field direction in the three-dimensional Ising model vanishes as $m_q^{2/5}$ when mapped onto the QCD $T-{\mu }_B$ phase plane. By selecting two distinct small angles and projecting the Ising model results onto QCD, we have investigated the universal critical behavior of the sixth-, eighth-, and tenth-order susceptibilities of the net-baryon number. When considering only the leading critical contribution, the negative dip in the ${\mu }_B$ dependence of the generalized susceptibilities is not universal, in contrast to the observation in the case where the angle is $90^{\circ }$. Its existence depends on the mapping parameters and the distance to the phase transition line. After incorporating the sub-leading critical contribution, the negative dip is enhanced to some extent but remains a non-robust feature. In contrast, the positive peak structure persists in all cases and represents a robust characteristic of generalized susceptibilities of the net-baryon number near the critical point.

    ↳ nucl-thhep-phhep-thIJMPE(2025)·0 citations
33. 33*

    Lorentz Invariance Violation from Gamma-Ray Bursts

    Hanlin Song🇨🇳 · Bo-Qiang Ma🇨🇳

    Lorentz invariance violation (LV) is examined through the time delay between high-energy and low-energy photons in gamma-ray bursts (GRBs). Previous studies determined the LV energy scale as $E_{\mathrm{LV}}\simeq 3.60\times 10^{17}$~GeV using Fermi Gamma-ray Space Telescope (FGST) data. This study updates the time-delay model and reaffirms these findings with new observations. High-energy photons from GRBs at GeV and TeV bands are analyzed, including the 99.3 GeV photon from GRB 221009A (FGST), the 1.07 TeV photon from GRB 190114C (MAGIC), and the 12.2 TeV photon from GRB 221009A (LHAASO). Our analysis, in conjunction with previous data, consistently shows that high-energy photons are emitted earlier than low-energy photons at the source. By evaluating 17 high-energy photons from 10 GRBs observed by FGST, MAGIC, and LHAASO, we estimate the LV energy scale to be $E_{\mathrm{LV}}\simeq 3.00\times 10^{17}$ GeV. The null hypothesis of dispersion-free vacuum $E=pc$ (or, equivalently, the constant light-speed $v_{\gamma }=c$) is rejected at a significance level of 3.1$\sigma$ or higher.

    ↳ astro-ph.HEgr-qchep-phApJ(2025)·10 citations
34. 34*

    Dynamical Dark Energy Implies a Coupled Dark Sector: Insights from DESI DR2 via a Data-Driven Approach

    Changyu You🇨🇳 · Dan Wang🇨🇳 · Tao Yang🇨🇳

    Recent observations from the Dark Energy Spectroscopic Instrument (DESI) Data Release 2 (DR2) have revealed compelling evidence for dynamical dark energy, challenging the $\Lambda$CDM paradigm. In this work, we adopt a data-driven, model-independent approach to reconstruct the dark energy equation of state (EoS) and its potential interaction with dark matter using combined background cosmological datasets, including DESI DR2, cosmic chronometers, observational Hubble data, and Type Ia supernovae. Using Gaussian Process regression and a non-parametric formalism, we first confirm a $\sim 2\sigma$ indication of dynamical dark energy, featuring a phantom crossing around redshift $z\sim 0.4$, consistent with DESI results. We then explore the implications of dynamical EoS from DESI DR2 for dark sector coupling. Incorporating priors on the EoS from DESI DR2, we find a $\sim 2\sigma$ signal for non-zero interactions between dark energy and dark matter at low redshift. Our results suggest that if DESI's evidence for time-varying dark energy is confirmed, a coupled dark sector may be a necessary extension beyond $\Lambda$CDM.

    ↳ astro-ph.COastro-ph.IMhep-phPRD(2025)·60 citations
35. 35*

    Bootstrapping LSS perturbation theory beyond third order

    Arhum Ansari🇮🇳 · Arka Banerjee🇮🇳 · Sachin Jain🇮🇳 · Sahil Lalsodagar🇮🇳

    Bootstrap techniques relying on the constraints imposed by Extended Galilean Invariance (EGI), have proved to be very useful in the context of perturbation theory of the Large Scale Structure (LSS). It has been formulated in both the Eulerian as well as Lagrangian space. While the Eulerian bootstrap formalism has been successfully applied to both tracer and matter kernels, the application of bootstrap methods in Lagrangian space has so far been restricted to matter. Up to third order, it has been shown that implementing EGI constraints in Eulerian space fully reproduces the bias expansion for tracers. Previous studies have demonstrated that time non-locality affects the bias expansion in a non-trivial way starting from fifth order. Motivated by this fact, we extend the bootstrap approach upto fifth order in both Eulerian and Lagrangian space and demonstrate that it fully captures the time non-local effects. For this, we generalize the Lagrangian bootstrap for tracers, and found that it agrees with the corresponding results obtained in Eulerian space. One of the major challenges in implementing EGI constraints in Eulerian space, is to systematically find out all the "spurious poles" and make them vanish. We have proposed a method that bypasses this difficulty making the procedure tractable at higher orders. From Lagrangian perspective, we have identified coefficients in the tracer kernel whose ratios are independent of tracer properties and may serve as direct probes of the underlying cosmology.

    ↳ astro-ph.COhep-phhep-thJCAP(2025)·7 citations
36. 36*

    MATHUSLA: An External Long-Lived Particle Detector to Maximize the Discovery Potential of the HL-LHC

    Branden Aitken🇨🇦 · Cristiano Alpigiani🇺🇸 · Juan Carlos Arteaga-Velázquez🇲🇽 · Mitchel Baker🇨🇦 · Kincso Balazs🇨🇭 · Jared Barron🇺🇸 · Brian Batell🇺🇸 · Austin Batz🇺🇸 · Yan Benhammou🇮🇱 · Tamara Alice Bud🇨🇭 · Karen Salomé Caballero-Mora🇲🇽 · John Paul Chou🇺🇸 and 61 other authors

    We present the current status of the MATHUSLA (MAssive Timing Hodoscope for Ultra-Stable neutraL pArticles) long-lived particle (LLP) detector at the HL-LHC, covering the design, fabrication and installation at CERN Point 5. MATHUSLA40 is a 40 m-scale detector with an air-filled decay volume that is instrumented with scintillator tracking detectors, to be located near CMS. Its large size, close proximity to the CMS interaction point and about 100 m of rock shielding from LHC backgrounds allows it to detect LLP production rates and lifetimes that are one to two orders of magnitude beyond the ultimate reach of the LHC main detectors. This provides unique sensitivity to many LLP signals that are highly theoretically motivated, due to their connection to the hierarchy problem, the nature of dark matter, and baryogenesis. Data taking is projected to commence with the start of HL-LHC operations. We summarize the new 40m design for the detector that was recently presented in the MATHUSLA Conceptual Design Report, alongside new realistic background and signal simulations that demonstrate high efficiency for the main target LLP signals in a background-free HL-LHC search. We argue that MATHUSLA's uniquely robust expansion of the HL-LHC physics reach is a crucial ingredient in CERN's mission to search for new physics and characterize the Higgs boson with precision.

    ↳ physics.ins-dethep-exhep-ph10 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.