Mon·Mar 17, 2025Monday·March 17, 2025

1. 01*

   Next-to-leading power jet functions in the small-mass limit in QED

   Robin van Bijleveld🇳🇱 · Eric Laenen🇳🇱 · Coenraad Marinissen🇳🇱 · Leonardo Vernazza🇮🇹 · Guoxing Wang🇫🇷

   We investigate the factorization properties of the massive fermion form factor in QED, to next-to-leading power in the fermion mass, and up to two-loop order. For this purpose we define new jet functions that have multiple connections to the hard part as operator matrix elements, and compute them to second order in the coupling. We test our factorization formula using these new jet functions in a region-based analysis and find that factorization indeed holds. We address a number of subtle aspects such as rapidity regulators and external line corrections, and we find an interesting sequence of relations among the jet functions.

   hep-phJHEP(2025)·10 citations
2. 02*

   On Gauge Theories of Neutrino Masses and Dark Matter

   Hridoy Debnath🇺🇸 · Pavel Fileviez Perez🇺🇸

   We discuss the predictions in the simplest theory for neutrino masses based on the spontaneous breaking of local lepton number. This theory provides a simple theoretical framework to understand the possible relation between the origin of neutrino masses and the nature of the dark matter. In this theory, one of the fields needed for anomaly cancellation is a dark matter candidate and the local lepton number is broken at the low scale. We discuss in great detail the dark matter properties showing the allowed parameter space by the relic density bounds and the predictions for direct detection. The predictions for gamma and neutrino lines from dark matter annihilation are investigated. In the case of Dirac neutrinos, the bound on the effective number of relativistic degrees of freedom plays an important role and the predictions for gamma lines could be tested in the near future. We discuss the predictions in the case of Majorana neutrinos where the dark matter candidate has extra annihilation channels and compare all the predictions to the case with Dirac neutrinos.

   hep-phastro-ph.COhep-exPRD(2025)·2 citations
3. 03*

   Exclusive photoproduction of ${\chi }_c\gamma$ pairs

   Marat Siddikov🇨🇱 · Ivan Zemlyakov🇨🇱

   In this manuscript we study the exclusive photoproduction of ${\chi }_c\gamma$ pairs in the collinear factorization framework. We found the coefficient functions for all possible spins and helicity projections of ${\chi }_c$ mesons and final-state photons in the leading order in the strong coupling ${\alpha }_s$. In our analysis we focused on the contribution of the leading twist chiral even GPDs, and found that for all spin states of ${\chi }_c$ the suggested process is determined by the behavior of the gluon GPDs $H_g$ in the ERBL kinematics. Using the phenomenological parametrizations of the GPDs from the literature, we estimated numerically the photoproduction cross-sections and the expected counting rates in the kinematics of middle-energy photoproduction experiments that could be realized at the Electron-Ion Collider. We observed that the ${\chi }_{c1}$, ${\chi }_{c2}$ mesons are produced predominantly with the same polarization as the incoming photon, and the expected counting rates of ${\chi }_{c1}\gamma$ and ${\chi }_{c2}\gamma$ pairs are sufficiently large for their experimental study. We also analyzed the angular distribution of ${\chi }_c$ mesons in electroproduction experiments, and noticed that for some helicity components there are sizable angular asymmetries, which can be used as complementary observables for experimental study. Finally, we estimated the role of this process as a potential background to ${\chi }_c$ photoproduction, which has been recently suggested as a tool for studies of odderons. We found that the contribution of ${\chi }_c\gamma$ (with undetected photon) is on par with expected contributions of odderons and Primakoff mechanisms in the kinematics of small momentum transfer $|t|\lesssim 1$ GeV${}^2$, but becomes negligible at larger $|t|$.

   hep-phPRD(2025)·2 citations
4. 04*

   Exclusive photon-fusion production of even-spin resonances and exotic QED atoms in high-energy hadron collisions

   David d'Enterria🇨🇭 · Karen Kang🇺🇸

   The cross sections for the single exclusive production of (pseudo)scalar and (pseudo)tensor hadrons, as well as of even-spin QED bound states formed by pairs of opposite-charge leptons or hadrons, are estimated for photon-fusion processes in ultraperipheral collisions (UPCs) of proton-proton, proton-nucleus, and nucleus-nucleus at the RHIC, LHC and FCC colliders, as well as in proton-air interactions at the highest energies reached by cosmic-rays impinging on Earth. The UPC cross sections are computed in the equivalent photon approximation with realistic photon fluxes from the charged form factors of proton, lead, gold, and nitrogen ions. The production of four types of even-spin systems are considered: quarkonium (spin-0,2,4 meson bound states, from the lightest ${\pi }^0$ meson up to toponium), exotic hadrons (including candidate multiquark states), leptonium (positronium, dimuonium, and ditauonium), as well as mesonium (pionium, kaonium, D-onium, and B-onium) and baryonium (notably, protonium) QED atoms. The expected yields at the different colliders are presented for about 50 such even-spin composite resonances, for which the ALICE and LHCb experiments have potential reconstruction capabilities at the LHC. The impact of the diphoton decays of such even-spin states is also discussed as resonant backgrounds in the measurement of light-by-light scattering ($\gamma \gamma \to \gamma \gamma$) over $m_{\gamma \gamma }=0.1$--15 GeV in PbPb UPCs at the LHC.

   hep-phhep-exnucl-exnucl-thPRD(2025)·16 citations
5. 05*

   Attractive features of Higgsino Dark Matter in the Next-to-Minimal Supersymmetric Standard Model

   Yuanfang Yue🇨🇳 · Junjie Cao🇨🇳 · Fei Li🇨🇳 · Zehan Li🇨🇳

   In the Higgsino dark matter (DM) scenario of the Minimal Supersymmetric Model (MSSM), the mixing of Gaugino and Higgsino influences the mass splitting between neutralinos predominantly composed of Higgsino and introduces coupling between the DM and Higgs bosons. These effects modify the DM-nucleon scattering cross-section, causing conflicts with the latest direct detection results from LZ experiments for both substantial and minute mixings. Consequently, the experimental measurement of DM relic density necessitates the Higgsino DM mass to be approximately 1.1 TeV. We discovered that in the Higgsino DM scenario of the Next-to-Minimal Supersymmetric Model (NMSSM), the mixing of Higgsino and Singlino introduces analogous effects, with a crucial distinction being that the current LZ experiment permits significant mixing between Singlino and Higgsino. This pronounced mixing effect effectively attenuates the interactions between Higgsino-dominated neutralinos and standard model particles, enabling DM masses exceeding roughly 670 GeV to achieve the correct relic abundance. Through analytical formulas and numerical results, we elucidated these characteristics which were not observed before. Our research reveals that in the NMSSM, when comprehensively examining the mixing effects of Higgsino, Gaugino, and Singlino, the properties of Higgsino DM become markedly more intricate compared to the MSSM predictions.

   hep-phPRD(2025)·5 citations
6. 06*

   Analysis of bound and resonant states of doubly heavy tetraquarks with spin $J\le 2$

   Manato Sakai🇯🇵 · Yasuhiro Yamaguchi🇯🇵

   Recently, a number of exotic hadrons have been reported in the experiments, and most of these states lie slightly below the threshold. Therefore, these states are considered to be hadronic molecules composed of mesons or baryons. In 2022, the doubly charmed tetraquark $T_{cc}$ was reported by the LHCb experiment, which is considered to be composed of two heavy quarks and two light antiquarks, and located slightly below the $D{D}^{\ast }$ threshold. The observation motivates us to study the bound and resonant states of the doubly heavy tetraquarks as two meson systems. We employ the one boson exchange potential as an interaction between two mesons, where one free parameter has been determined to reproduce $T_{cc}$ reported by the LHCb experiment. In our previous work, bound states of $D^{(\ast )}{D}^{(\ast )}$ and $B^{(\ast )}{B}^{(\ast )}$ molecules were studied, where we respected the heavy quark spin symmetry (HQS). Using the same framework, we study not only bound but also resonant states with $J\le 2$ in this paper. Furthermore, we discuss the HQS partner structures of $T_{cc}$ and $T_{bb}$ obtained in our study by introducing the light cloud basis.

   hep-phPRD(2025)·11 citations
7. 07*

   Origin of CKM matrix and natural FCNC suppression in gauge-Higgs unification

   Yutaka Hosotani🇯🇵 · Shuichiro Funatsu🇯🇵 · Hisaki Hatanaka🇯🇵 · Yuta Orikasa🇨🇿 · Naoki Yamatsu🇯🇵

   In the $SO(5)\times U(1)\times SU(3)$ gauge-Higgs unification in the Randall-Sundrum warped space the mixing in the $W$ couplings in the quark sector is induced by masses of $SO(5)$ singlet fermions which are responsible for splitting masses of down-type quarks from those of up-type quarks in each generation. We show that the observed Cabibbo-Kobayashi-Maskawa (CKM) matrix in the $W$ couplings is reproduced within experimental errors. Further flavor-changing neutral currents (FCNCs) in the quark sector are shown to be naturally suppressed.

   hep-phPRD(2025)·2 citations
8. 08*

   Radiative Energy and Mass Shifts of Quantum Cyclotron States

   Ulrich D. Jentschura🇺🇸

   We discuss relativistic and radiative corrections to the energies of quantum cyclotron states. In particular, it is shown analytically that the leading logarithmic radiative (self-energy) correction to the bound-state energy levels of quantum cyclotron states is state-independent, and must be interpreted as a magnetic-field-dependent correction to the electron's mass in a Penning trap.

   hep-phEur.Phys.J.D(2025)·0 citations
9. 09*

   Determination of unpolarized TMD distributions from the fit of Drell-Yan and SIDIS data at N${}^4$LL

   Valentin Moos🇹🇼 · Ignazio Scimemi🇪🇸 · Alexey Vladimirov🇪🇸 · Pia Zurita🇩🇪

   We present a fit of the transverse momentum spectrum for Drell-Yan and semi-inclusive deep inelastic scattering data, based on transverse momentum dependent (TMD) factorization at N${}^4$LL accuracy. Our analysis shows good agreement with the data and confirms the findings of previous studies. Based on this, we extract the unpolarized TMD parton distribution functions, the TMD fragmentation functions, and the Collins-Soper kernel. Compared to earlier works, our study incorporates several improvements, including large-$x$ resummation, flavor and fragmentation function dependence, among others. Additionally, we supplement our extraction with an analysis of the transverse momentum moments of the extracted distributions.

   hep-phJHEP(2025)·57 citations
10. 10*

    Revisiting $B_c^{-}\to J/\psi ({\eta }_c)L^{-}$ decays within the SM and beyond in QCD factorization

    Wei-Jun Deng🇨🇳 · Fang-Min Cai🇨🇳 · Xin-Qiang Li🇨🇳 · Yan Shi🇨🇳 · Ya-Dong Yang🇨🇳

    Motivated by the deviations observed between the data and the SM predictions of $\mathcal{B}({\bar{B}}_s^0\to D_s^{+}{\pi }^{-})$ and $\mathcal{B}({\bar{B}}_d^0\to D^{+}{K}^{-})$, we revisit the $B_c^{-}\to J/\psi ({\eta }_c)L^{-}$ decays, with $L=\pi ,K^{(\ast )},\rho$, both within the SM and beyond. Since these processes are also mediated by $b\to c\bar{u}d(s)$ transitions and hence dominated by the colour-allowed tree topology, the QCD factorization (QCDF) is expected to hold in the heavy-quark limit. Firstly, we update the SM predictions of these decays by including the nonfactorizable vertex corrections up to the NNLO in ${\alpha }_s$. It is found that, relative to the LO results, the branching ratios of these decays up to the NLO and NNLO corrections are always enhanced, with a relative amount given by ${\delta }_{\text{NLO}}=({\mathcal{B}}^{\text{NLO}}-{\mathcal{B}}^{\text{LO}})/{\mathcal{B}}^{\text{LO}}\approx +6\%$ and ${\delta }_{\text{NNLO}}=({\mathcal{B}}^{\text{NNLO}}-{\mathcal{B}}^{\text{LO}})/{\mathcal{B}}^{\text{LO}}\approx +9\%$, respectively. To minimize the uncertainties brought by $V_{cb}$ and the transition form factors, we construct the ratios $R_{J/\psi ({\eta }_c)L}$, $R_{(s)L}^{(\ast )}$, and $R_{\pi /\mu {\nu }_{\mu }}$, which are then used to constrain the model-independent new physics (NP) Wilson coefficients. After considering the latest Belle data and the updated $B_{(s)}\to D_{(s)}^{(\ast )}$ form factors, we find that the deviations can still be explained by the NP four-quark operators with $(1+{\gamma }_5)\otimes (1-{\gamma }_5)$ and $(1+{\gamma }_5)\otimes (1+{\gamma }_5)$ structures, while the solution with ${\gamma }^{\mu }(1+{\gamma }_5)\otimes {\gamma }_{\mu }(1-{\gamma }_5)$ structure does not work anymore, under the combined constraints from $R_{(s)L}^{(\ast )}$ at the $2\sigma$ level. Furthermore, the ratio $R_{\pi /\mu {\nu }_{\mu }}$, once measured precisely, could provide complementary constraint.

    hep-phPRD(2025)·2 citations
11. 11*

    Gravitational form factors in the perturbative limit

    Qin-Tao Song🇨🇳 · O. V. Teryaev🇷🇺 · Shinsuke Yoshida🇨🇳

    Generalized distribution amplitudes (GDAs) have attracted significant attention in recent years due to their connection with the energy-momentum tensor (EMT) form factors (FFs). The GDAs can be experimentally accessed through the study of amplitudes in ${\gamma }^{\ast }\gamma \to M_1{M}_2$ and ${\gamma }^{\ast }\to M_1{M}_2\gamma$, where $M_1{M}_2$ is a pseudoscalar meson pair such as $\pi \eta$ and $\eta {\eta }^{\prime }$. In this work, we calculate these amplitudes in the perturbative limit and express the extracted $M_1{M}_2$ GDAs in terms of meson distribution amplitudes that have been constrained by the previous experiments. Our explicit calculation verifies the existence of a new EMT FF that violates the conservation law of EMT when the hadronic matrix element of the EMT operator is considered separately for each quark flavor. In addition, our result shows that the $M_1{M}_2$ GDAs are identical in ${\gamma }^{\ast }\gamma \to M_1{M}_2$ and ${\gamma }^{\ast }\to M_1{M}_2\gamma$, which confirms the universality of GDAs in the perturbative limit. In the future, the GDAs and the EMT FFs studied in this paper can be probed at Belle II. Our study enhances the accessibility to the $P$-wave GDAs in ${\gamma }^{\ast }\gamma \to M_1{M}_2$ and ${\gamma }^{\ast }\to M_1{M}_2\gamma$, and provides a promising approach for searching for exotic hybrid mesons in future experiments.

    hep-phhep-lathep-thnucl-ex+1PLB(2025)·9 citations
12. 12*

    Probing fundamental physics using compact astrophysical objects

    E.-A. Kolonia🇬🇷 · C. J. A. P. Martins🇵🇹 · Konstantinos N. Gourgouliatos🇬🇷

    It is well known that alternative theories to the Standard Model allow -- and sometimes require -- fundamental constants, such as the fine-structure constant, $\alpha$, to vary in spacetime. We demonstrate that one way to investigate these variations is through the Mass-Radius relation of compact astrophysical objects, which is inherently affected by $\alpha$ variations. We start by considering the model of a polytropic white dwarf, which we perturb by adding the $\alpha$ variations for a generic class of Grand Unified Theories. We then extend our analysis to neutron stars, building upon the polytropic approach to consider more realistic equations of state, discussing the impact of such variations on mass-radius measurements in neutron stars. We present some constraints on these models based on current data and also outline how future observations might distinguish between extensions of the Standard Model.

    hep-phastro-ph.HEgr-qcPRD(2025)·1 citation
13. 13*

    Identified Hadron Production at Hadron Colliders in Next-to-Next-to-Leading-Order QCD

    Michał Czakon🇩🇪 · Terry Generet🇬🇧 · Alexander Mitov🇬🇧 · Rene Poncelet🇵🇱

    In this work we calculate for the first time the next-to-next-to leading order (NNLO) QCD corrections to identified hadron production at hadron colliders. The inclusion of the NNLO correction has an important impact on all observables considered in this work. Higher order corrections reduce scale uncertainty and in almost all cases are moderate. Overall, good perturbative convergence is observed across kinematics and observables. The uncertainty due to missing higher orders is relatively small and, in many cases, smaller than the experimental uncertainty. The largest source of theoretical uncertainty at present is from the knowledge of the non-perturbative parton-to-hadron fragmentation functions (FF), which dwarfs the scale uncertainty in most kinematic ranges. The inclusion of NNLO corrections demonstrates the precision studies potential of this class of observables. To fully realize this potential, however, a new generation of improved fragmentation functions may be needed. The results of the present work will enable global fits of FF with NNLO precision.

    hep-phhep-exnucl-exnucl-thPRL(2025)·17 citations
14. 14*

    Future collider constraints on top-quark operators

    Fernando Cornet-Gomez🇺🇸 · Víctor Miralles🇬🇧 · Marcos Miralles López🇬🇧 · María Moreno Llácer🇪🇸 · Marcel Vos🇪🇸

    In this paper we present updated constraints on the top-quark sector of the Standard Model Effective Field Theory using data available from Tevatron, LEP and the LHC. Bounds are obtained for the Wilson coefficients from a global fit including the relevant two-fermion operators, four-quark operators and two-quark two-lepton operators. We compare the current bounds with the prospects for the high luminosity phase of the Large Hadron Collider and future lepton colliders.

    hep-phhep-exJHEP(2025)·24 citations
15. 15*

    Electroweak Symmetry Breaking

    J. W. Moffat🇨🇦

    This paper examines the Higgs particle self-coupling and its implications for electroweak symmetry breaking in the Standard Model. We review the current experimental constraints on the Higgs trilinear coupling and discuss the challenges in measuring it precisely. The potential consequences of deviations from the Standard Model prediction are explored, including the possibility of new physics. We then consider an alternative ultraviolet complete electroweak theory based on finite quantum field theory, which does not require spontaneous symmetry breaking or a non-zero vacuum expectation value. The predictions of this model for particle masses and the stability of the electroweak vacuum are compared to the standard Higgs mechanism. Finally, we review the SM derivation of the W-boson mass, its dependence on radiative corrections and its experimentally determined value.

    hep-phhep-th2 citations
16. 16*

    Penguin decays of B mesons

    Aritra Biswas🇩🇪

    We propose a set of optimized observables using penguin mediated ${\bar{B}}_d$ and ${\bar{B}}_s$ decays to $K^{(\ast )}{\bar{K}}^{(\ast )}$ and $K^{\ast }\varphi$ final states that exhibhit a reduced sensitivity to power corrections than the corresponding branching ratios. Using these observables, branching ratios for the related vector-vector and pseudoscalar-pseudoscalar modes and branching ratios for modes involving other relevant pseudoscalar-vector final states ($K\varphi$, $K^{\ast }\bar{K})$, we attempt to resolve the emergent combined pattern by assuming new physics contributions to the weak effective operators at the scale of the mass of the $b$ quark that are already present in the Standard Model. We find that the simplest scenario that can offer a simultaneous explanation is the two-operator scenario $Q_{4s,d}-Q_{6s,d}$. We briefly discuss how future experimental measurements may alter this picture and try to motivate such measurements for specific modes from our analysis.

    hep-phPoS(2025)·0 citations
17. 17*

    Self-Supervised Learning Strategies for Jet Physics

    Patrick Rieck🇺🇸 · Kyle Cranmer🇺🇸 · Etienne Dreyer🇮🇱 · Eilam Gross🇮🇱 · Nilotpal Kakati🇮🇱 · Dmitrii Kobylanskii🇮🇱 · Garrett W. Merz🇺🇸 · Nathalie Soybelman🇮🇱

    We extend the re-simulation-based self-supervised learning approach to learning representations of hadronic jets in colliders by exploiting the Markov property of the standard simulation chain. Instead of masking, cropping, or other forms of data augmentation, this approach simulates pairs of events where the initial portion of the simulation is shared, but the subsequent stages of the simulation evolve independently. When paired with a contrastive loss function, this naturally leads to representations that capture the physics in the initial stages of the simulation. In particular, we force the hard scattering and parton shower to be shared and let the hadronization and interaction with the detector evolve independently. We then evaluate the utility of these representations on downstream tasks.

    hep-phhep-exMach.Learn.Sci.Tech.(2025)·3 citations
18. 18*

    Mechanical Sensors for Ultraheavy Dark Matter Searches via Long-range Forces

    Juehang Qin🇺🇸 · Dorian W. P. Amaral🇺🇸 · Sunil A. Bhave🇺🇸 · Erqian Cai🇺🇸 · Daniel Carney🇺🇸 · Rafael F. Lang🇺🇸 · Shengchao Li🇺🇸 · Alberto M. Marino🇺🇸 · Giacomo Marocco🇺🇸 · Claire Marvinney🇺🇸 · Jared R. Newton🇺🇸 · Jacob M. Taylor🇺🇸 · Christopher Tunnell🇺🇸

    Dark matter candidates with masses around the Planck-scale are theoretically well-motivated, and it has been suggested that it might be possible to search for dark matter solely via gravitational interactions in this mass range. In this work, we explore the pathway towards searching for dark matter candidates with masses around the Planck-scale using mechanical sensors while considering realistic experimental constraints, and develop analysis techniques needed to conduct such searches. These dark matter particles are expected to leave tracks as their signature in mechanical sensor arrays, and we show that we can effectively search for such tracks using statistical approaches to track-finding. We analyze a range of possible experimental setups and compute sensitivity projections for searches for ultraheavy dark matter coupling to the Standard Model via long-range forces. We find that while a search for Planck-scale dark matter purely via gravitational couplings would be exceedingly difficult, requiring $\sim 80\mathrm{dB}$ of quantum noise reduction with a $100^3$ array of devices, there is a wide range of currently unexplored dark matter candidates which can be searched for with already existing or near-term experimental platforms.

    hep-phhep-exquant-phPRD(2025)·9 citations
19. 19*

    Factorization in deep inelastic scattering at Björken limit: Reduction to (1+1)D integrable models

    H. Babujian🇦🇲 · M. Karowski🇩🇪 · A. Sedrakyan🇦🇲

    We investigate structure functions in deep inelastic scattering processes (DIS) at Björken limit and found that they are factorized into the longitudinal and transversal parts. We see that the longitudinal part can be linked to exact form factors calculated earlier in 1+1 dimensional integrable quantum field theories, such as sine-Gordon model. We extract asymptotic of Form-factors at small Björken parameter $x$ and compare it with experimental data of HERA and ZEUS collaborations on Deep inelastic lepton-proton scattering. We observe the factorization of the structure functions $F_2(x,q^2)$ and find out its power behavior on scaling parameter $x$.

    hep-phhep-th1 citation
20. 20*

    First constraints on QCD axion dark matter using James Webb Space Telescope observations

    Elena Pinetti🇺🇸

    I present the first constraints on QCD axion dark matter using measurements from the James Webb Space Telescope. By utilizing publicly available MIRI and NIRSpec blank-sky observations, originally collected for sky subtraction purposes, I derive strong limits on the axion-photon coupling constant $g_{a\gamma \gamma }$ in the mass range 0.1-4 eV. These constraints improve upon previous studies by more than two orders of magnitude for a range of masses. This analysis underscores the potential of blank-sky observations as a powerful tool for constraining dark matter models and demonstrates how astrophysical missions can be repurposed for particle physics research.

    hep-phastro-ph.CO25 citations
21. 21*

    From obstacle to opportunity: uncovering the silver lining of pileup

    Biplob Bhattacherjee🇮🇳 · Abhinav Kumar🇮🇳 · Swagata Mukherjee🇮🇳 · Rhitaja Sengupta🇩🇪 · Anand Sharma🇮🇳

    The lack of evidence for Beyond Standard Model (BSM) particles might be due to their light mass and very weak interactions, as exemplified by BSM long-lived particles (LLPs). Such particles can be produced from $B$ or $D$ hadron decays. Typically, the high values of pileup (PU) in hadron colliders are expected to pose a major challenge in light new physics searches. We propose a fresh perspective that counters this conventional wisdom: instead of viewing PU solely as an impediment, we highlight its potential benefits in searches for light LLPs from $B$ or $D$ hadron decays at HL-LHC and FCC-hh. In particular, certain forward detectors in LHC experiments, such as the Zero Degree Calorimeters (ZDC), which are currently not utilized for LLP searches, can be repurposed with strategic modifications to play a crucial role in this endeavor. Leveraging a combination of forward and central detectors, along with smart strategies for triggering and offline analysis, we demonstrate the potential for exploring light LLPs in high PU scenarios.

    hep-phhep-exPLB(2026)·4 citations
22. 22*

    Testing the QCD formation time with reconstructed parton splittings

    Jasmine Brewer🇬🇧 · Wilke van der Schee🇨🇭 · Urs Wiedemann🇨🇭

    In high-energy elementary collisions the space-time ordering of parton branching processes is not accessible experimentally. In contrast, in heavy-ion collisions, parton showers interact with a spatially extended dense medium. This sets a reference length scale with respect to which the space-time ordering may be analysed. Here, we explore the possibility of identifying experimental signatures of the QCD formation time, ${\tau }_f$, on the level of a single parton splitting. Since heavy flavour offers an additional handle on tracing the propagation of individual quarks through the medium, we focus on the $g\to c\bar{c}$ splitting. Combining adapted versions of the Cambridge-Aachen and FlavourCone jet finding algorithms with grooming techniques, we show how the kinematics of such splittings can be reconstructed with high fidelity using either final state partons or hadrons, and how the formation time distribution of parton splittings can be constructed therefrom. Medium modification leads to a characteristic modification of this ${\tau }_f$ distribution. This effect can be used to construct experimentally-accessible ratios of ${\tau }_f$ distributions, in which the sensitivity of the medium modification to the QCD formation time becomes measurable.

    hep-phnucl-exnucl-th5 citations
23. 23*

    Neutrino nonstandard interactions: Confronting COHERENT and LHC data

    Víctor Martín Lozano🇪🇸 · G. Sanchez Garcia🇪🇸 · Adrián Terrones🇪🇸

    We study the complementarity between COHERENT and LHC searches in testing neutrino nonstandard interactions (NSIs) through the completion of the effective field theory approach within a $Z^{\prime }$ simplified model. Our results show that LHC bounds are strongly dependent on the $Z^{\prime }$ mass, with relatively large masses excluding regions in the parameter space that are allowed by COHERENT data and its future expectations. We demonstrate that the combination of low- and high-energy experiments results in a viable approach to break NSI degeneracies within the context of simplified models.

    hep-phPRD(2025)·6 citations
24. 24*

    Forecasting Constraints on SIGW with Future Pulsar Timing Array Observations

    Chiara Cecchini🇮🇹 · Gabriele Franciolini🇨🇭 · Mauro Pieroni🇨🇭

    Pulsar Timing Arrays are playing a crucial role in the ongoing gravitational wave astronomy revolution. The current evidence for a stochastic gravitational wave background (SGWB) at nHz frequencies offers an opportunity to discover cosmological signals and threatens the observability of other subdominant GWs. We explore prospects to constrain second-order scalar-induced GWs (SIGWs) associated with enhanced curvature perturbations in the primordial universe, forecasting realistic future PTA datasets. We assess how the currently observed signal could eventually limit future capabilities to search for GW relics of primordial phenomena and associated phenomenological consequences such as primordial black hole (PBH) formation. Given the sensitivity of PBH abundance to spectral parameters, measuring it remains a challenge for realistic signals. However, future observation could still rule out nearly subsolar mass PBHs formed through standard formation scenarios in some cases. Future progress in constraining PBH models is expected to stem from theoretical advancements in PBH computations, which should help resolve the tension between different computational methods. The analysis is based on and extends the Python code $\text{fastPTA}$.

    ↳ astro-ph.COastro-ph.HEgr-qchep-phPRD(2025)·24 citations
25. 25*

    DESI results: Hint towards coupled dark matter and dark energy

    Amlan Chakraborty🇮🇳 · Prolay K. Chanda🇮🇳 · Subinoy Das🇮🇳 · Koushik Dutta🇮🇳

    We investigate a scenario where a dark energy quintessence field $\varphi$ with positive kinetic energy is coupled with dark matter. With two different self-interaction potentials for the field and a particular choice of the coupling function, we show explicitly how the observable effective equation of state parameter $w_{\mathrm{eff}}$ for the dark energy field crosses the phantom barrier ($w_{\mathrm{eff}}=-1$) while keeping the equation of state of the quintessence field $w_{\varphi }>-1$. With appropriate choices of parameters, $w_{\mathrm{eff}}$ crosses the phantom divide around redshift $z\sim 0.5$, transitioning from $w_{\mathrm{eff}}<-1$ in the past to $w_{\mathrm{eff}}>-1$ today. This explains DESI observations well. Our analysis reveals that the model remains consistent within the $2\sigma$ confidence intervals provided by DESI for several combinations of the scalar field parameters, highlighting its potential in explaining the dynamics of dark energy arising from a simple Yukawa-type long-range interaction in the dark sector. While the current findings offer a promising framework for interpreting DESI observations, future work, including a comprehensive Markov Chain Monte Carlo (MCMC) analysis, is necessary to constrain the parameter space further and strengthen the statistical significance of the results.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2025)·99 citations
26. 26*

    Triple-charmed Hadron from Coalescence in Relativistic Heavy-Ion Collisions

    Tianyang Li🇨🇳 · Jiamin Liu🇨🇳 · Shiqi Zheng🇺🇸 · Baoyi Chen🇨🇳

    We investigate the production of the ${\Omega }_{ccc}$ baryon in relativistic heavy-ion collisions. Unlike proton-proton collisions, nuclear collisions produce both deconfined matter and abundant charm quark pairs, which can coalesce to form the ${\Omega }_{ccc}$ baryon, thereby significantly enhancing its production. We employ the Langevin model and the Instantaneous Coalescence Model (LICM), coupled with hydrodynamic simulations, to study charm quark diffusion and coalescence into the ${\Omega }_{ccc}$ baryon in expanding QCD matter. The production of the ${\Omega }_{ccc}$ is governed by the charm quark densities and the in-medium wavefunctions of the ${\Omega }_{ccc}$, which determines the coalescence probability for the three charm quarks. We calculate the ${\Omega }_{ccc}$ production with realistic charm diffusions and different in-medium wave functions of ${\Omega }_{ccc}$ baryon. We find that the production of the ${\Omega }_{ccc}$ baryon is sensitive to these factors, which aids in understanding its properties in the hot QCD medium.

    ↳ nucl-thhep-phPLB(2025)·1 citation
27. 27*

    Growth of Cosmic Strings beyond Kination

    Luca Brunelli🇮🇹 · Michele Cicoli🇮🇹 · Francisco G. Pedro🇮🇹

    A novel mechanism for the production of a cosmic network of fundamental superstrings based on a time-varying string tension has been recently proposed in the context of a kinating background driven by the volume modulus of string compactifications. In this paper, we generalise the analysis of this growth mechanism by using dynamical system techniques. We first study the cosmological growth of strings in a spatially-flat Universe filled with a perfect fluid and a field-dependent tension, finding the fixed points of the phase space of this system. We then apply this analysis to fundamental strings and EFT strings obtained from wrapping $p$-branes on $(p-1)$-cycles. We find a cosmological growth for fundamental strings even without kination, as in scaling fixed points, and for EFT strings arising from D3- and NS5-branes wrapped around fibration cycles.

    ↳ hep-thastro-ph.COgr-qchep-phJCAP(2025)·15 citations
28. 28*

    Scaling and universality in strange quark stars

    G. Lugones🇧🇷 · A. G. Grunfeld🇦🇷

    We derive scaling laws that connect certain macroscopic observables of strange quark stars with key microscopic properties of self-bound quark matter, such as the energy per baryon at zero pressure and the strength of repulsive interactions. We also identify universal relations linking global properties of strange quark stars - specifically, their moment of inertia, tidal deformability, and both gravitational and baryonic compactness. Remarkably, these relations hold for two substantially different microscopic models - the quark-mass density-dependent model with excluded-volume corrections and the vector MIT bag model - underscoring their robust, model-independent nature. We demonstrate that the universal relations for strange quark stars differ significantly from those previously established for neutron stars composed of hadronic matter, thus enabling discrimination between the two types of objects without requiring detailed knowledge of their equations of state. Moreover, observational constraints on the maximum mass of compact stars could place bounds on both the depth of quark-matter self-binding and the strength of quark repulsive interactions.

    ↳ nucl-thastro-ph.HEastro-ph.SRhep-phPRD(2025)·5 citations
29. 29*

    Perturbations in pseudo-Nambu-Goldstone Higgs Inflation

    Stephon Alexander🇺🇸 · Humberto Gilmer🇺🇸 · Cooper Niu🇺🇸

    Pseudo-Nambu-Goldstone (pNG) Higgs Inflation is a novel approach to relate the Higgs boson and its interaction with Electroweak gauge bosons with cosmic inflation, with the potential of solving both the fine-tuning issues in the Higgs mass and inflationary potentials. In this work, we present a linear perturbation analysis of the minimal implementation of pNG Higgs inflation using the symmetry coset SU($5$)/SO($5$). Similar to Chromo-natural inflation, this model exhibits a period of instability in the tensor modes that exponentially enhance left-handed gravitational waves. Thus, large Chern-Simons couplings $\beta \gtrsim 6\times 10^8$ and decay constants $f\gtrsim 1\times 10^{18}\mathrm{GeV}$ are required to suppress the tensor-to-scalar ratio $r$ to be compatible with the cosmic microwave background (CMB) measurement. These large couplings also cause an overproduction of the scalar modes, making the minimal construction of pNG Higgs inflation disfavored by CMB observations. However, this tension could potentially be relieved by considering multi-field inflation. The pNG Higgs construction naturally contains multiple scalar fields via the interplay of spontaneously broken global and gauge symmetries. The rich structure enables a broad range of multi-field inflation, and we conclude by briefly discussing this possibility and future work.

    ↳ astro-ph.COgr-qchep-phJCAP(2025)·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.