Wed·Dec 13, 2023Wednesday·December 13, 2023

1. 01*

   Misalignment production of vector boson dark matter from axion-SU(2) inflation

   Tomohiro Fujita🇯🇵 · Kai Murai🇯🇵 · Kazunori Nakayama🇯🇵 · Wen Yin🇯🇵

   We present a new mechanism to generate a coherently oscillating dark vector field from axion-SU(2) gauge field dynamics during inflation. The SU(2) gauge field acquires a nonzero background sourced by an axion during inflation, and it acquires a mass through spontaneous symmetry breaking after inflation. We find that the coherent oscillation of the dark vector field can account for dark matter in the mass range of $10^{-13}-1$ eV in a minimal setup. In a more involved scenario, the range can be wider down to the fuzzy dark matter region. One of the dark vector fields can be identified as the dark photon, in which case this mechanism evades the notorious constraints for isocurvature perturbation, statistical anisotropy, and the absence of ghosts that exist in the usual misalignment production scenarios. Phenomenological implications are discussed.

   hep-phastro-ph.COJCAP(2024)·12 citations
2. 02*

   Unsupervised learning in the metric space of jets

   Tejes Gaertner🇬🇧 · Jared Reiten🇺🇸

   In the first part of this work, we demonstrate how the metric space structure induced by the energy mover's distance can be leveraged for the unsupervised tagging of jets according to their progenitor. Namely, we focus on the task of tagging jets initiated by a top quark from a background of jets initiated by light quarks and gluons. By examining the local neighborhood structure of this metric space, we find that the jets of each class populate the landscape in differing densities. This characteristic can be exploited to accurately cluster jets according to their densities through unsupervised clustering algorithms, such as DBSCAN. In the second part of this work, we modify the metric space by reducing the global notion of connectivity down to a local one and, in the process of doing so, modify our distance metric to be that corresponding to geodesics on an underlying graph. We demonstrate how this modification induces regions of both positive and negative values of curvature, which are then exacerbated through a Ricci flow algorithm. Differences in the curvatures averaged over local patches of the new graph metric space then lead to a flow which separates the signal top jets from the background in a fashion that is completely agnostic to any pre-determined jet labels.

   hep-ph4 citations
3. 03*

   QED corrections to the thermal neutrino interaction rate

   G. Jackson🇺🇸 · M. Laine🇨🇭

   Motivated by precision computations of neutrino decoupling at MeV temperatures, we show how QED corrections to the thermal neutrino interaction rate can be related to the electron-positron spectral function as well as an effective $\bar{\nu }\nu \gamma$ vertex. The spectral function is needed both in a timelike and in a spacelike domain, and for both of its physical polarization states (transverse and longitudinal with respect to spatial momentum). Incorporating an NLO evaluation of this spectral function, an estimate of the $\bar{\nu }\nu \gamma$ vertex, and HTL resummation of scatterings mediated by soft Bose-enhanced $t$-channel photons, we compute the interaction rate as a function of the neutrino momentum and flavour. Effects on the $-(\mathrm{0...2})\%$ level are found, noticeably smaller than a previous estimate of a related quantity.

   hep-phastro-ph.COJHEP(2024)·17 citations
4. 04*

   Axion Cloud Decay due to the Axion-photon Conversion with Multi-pole Background Magnetic Fields

   Yusuke Sakurai🇯🇵 · Chul-Moon Yoo🇯🇵 · Atsushi Naruko🇯🇵 · Daisuke Yamauchi🇯🇵

   We consider axion cloud decay due to the axion-photon conversion with multi-pole background magnetic fields. We focus on the $\ell =m=1$ and $n=2$ mode for the axion field configuration since it has the largest growth rate associated with superradiant instability. Under the existence of a background multi-pole magnetic field, the axion field can be converted into the electromagnetic field through the axion-photon coupling. Then the decay rate due to the dissipation of the converted photons is calculated in a successive approximation. We found that the decay rate is significantly dependent on the azimuthal quantum number characterizing the background magnetic field, and can be comparable to or larger than the growth rate of the superradiant instability.

   hep-phastro-ph.COgr-qchep-thJCAP(2024)·4 citations
5. 05*

   The complex heavy quark potential in an anisotropic quark-gluon plasma

   Ajaharul Islam🇺🇸

   We present a technique to represent anisotropic heavy-quark potentials as effective potentials. This involves employing an effective screening mass linked to the quantum numbers $l$ and $m$ of a specific state. Our approach utilizes the resulting 1D effective potential model, enabling the solution of a 1D Schrödinger equation. Remarkably, this model accurately reproduces the energies and binding energies of low-lying heavy-quarkonium bound states in 3D, including the differentiation of various p-wave polarizations. The derived 1D effective model offers a means to incorporate momentum anisotropy effects into simulations of heavy-quarkonium dynamics in the quark-gluon plasma within open quantum systems.

   hep-ph0 citations
6. 06*

   Revisiting the convergence of the perturbative QCD expansions based on conformal mapping of the Borel plane

   Irinel Caprini🇷🇴

   The difference between fixed-order (FO) and contour-improved (CI) formulations of QCD perturbation theory limits the precision of the strong coupling determined from the hadronic decay of the $\tau$ lepton. Recently, several attempts to understand the mathematical origin of the difference and to solve it by subtracting the dominant infrared renormalon divergence have been made. Motivated by these studies, we review in this paper an improved perturbative QCD expansion, defined some time ago, which also exploits the renormalons by means of a suitable conformal mapping of the Borel plane. In particular, we revisit the convergence of the new expansion, by completing the proof presented in a previous paper and showing that the domain of convergence is larger than stated before. We also check the validity of the convergence conditions for the Adler function and the CI and FO expansions of the $\tau$ hadronic spectral function moments, and compare the approach based on conformal mapping with recent solutions to the CIPT-FOPT discrepancy proposed in the literature.

   hep-phPRD(2023)·6 citations
7. 07*

   Neutrino Mass Matrices with Generalized CP Symmetries and Texture Zeros

   Sanjeev Kumar🇮🇳 · Radha Raman Gautam🇮🇳

   We investigate the properties of neutrino mass matrices that incorporate texture zeros and generalized CP symmetries associated with tribimaximal mixing. By combining these approaches, we derive predictive neutrino mass matrices and explore their implications for mass hierarchies, mixing angles, and CP-violating phases. We find that the three angles defining the generalized CP symmetries have narrow allowed ranges. We also obtain distinct correlations between the three mixing angles and the CP-violating phases that distinguish the various texture patterns from one another. Moreover, we compute the effective neutrino mass for neutrinoless double beta decay and the sum of neutrino masses. Our results highlight the predictability and testability of neutrino mass matrices with generalized CP symmetry.

   hep-phNPB(2024)·4 citations
8. 08*

   ${\overline{\mathrm{B}}}_{d,s}\to {\mathrm{K}}^{\ast 0}{\overline{\mathrm{K}}}^{\ast 0}$ decays, a serious problem for the Standard Model

   Roy Aleksan🇫🇷 · Luis Oliver🇫🇷

   We underline the theoretical and experimental interest of the vector-vector penguin decays ${\overline{\mathrm{B}}}_{d,s}\to {\mathrm{K}}^{\ast 0}{\overline{\mathrm{K}}}^{\ast 0}$ for which the data show a strong U-spin violation. Indeed, with the latest LHCb data one has for these two modes very different longitudinal polarization fractions, $f_L^{exp}({\overline{\mathrm{B}}}_s\to {\mathrm{K}}^{\ast 0}{\overline{\mathrm{K}}}^{\ast 0})=0.24\pm 0.04$ and $f_L^{exp}({\overline{\mathrm{B}}}_d\to {\mathrm{K}}^{\ast 0}{\overline{\mathrm{K}}}^{\ast 0})=0.74\pm 0.05$. This feature is very striking because both modes are related by the exchange $s\leftrightarrow d$, i.e. they are related by U-spin symmetry as pointed out in earlier work by other authors. We illustrate this phenomenon by computing different observables for these modes within the QCD Factorization scheme, and we find, as expected, rather close values for the longitudinal fractions, with central values $f_L^{th}({\overline{\mathrm{B}}}_s\to {\mathrm{K}}^{\ast 0}{\overline{\mathrm{K}}}^{\ast 0})\simeq 0.42$ and $f_L^{th}({\overline{\mathrm{B}}}_d\to {\mathrm{K}}^{\ast 0}{\overline{\mathrm{K}}}^{\ast 0})\simeq 0.49$ and rather small errors. Furthermore, due to the $V-A$ nature of the weak currents and the heavy quark limit, one expects $(f_{\parallel }/f_{\perp }{)}_{th}\simeq 1$, which in the ${\mathrm{B}}_{\mathrm{s}}$ case is in contradiction with the data $(f_{\parallel }/f_{\perp }{)}_{\exp }\simeq 0.44\pm 0.06$.}

   hep-phhep-ex4 citations
9. 09*

   Measuring $hhWW$ Coupling at Lepton Colliders

   Qing-Hong Cao🇨🇳 · Kun Cheng🇨🇳 · Yandong Liu🇨🇳 · Xiao-Rui Wang🇨🇳

   The quartic Higgs-gauge-boson coupling $g_{hhWW}$ is sensitive to the electroweak symmetry breaking mechanism, however, it is challenging to be measured at the large hadron collider. We show that the coupling can be well probed at future lepton colliders through di-Higgs boson production via the vector boson fusion channel. We perform a detailed simulation of ${\ell }^{+}{\ell }^{-}\to \nu \bar{\nu }hh\to 4b+/E_T$ with parton showering effects at $e^{+}{e}^{-}$, ${\mu }^{+}{\mu }^{-}$ and $e^{-}{\mu }^{+}$ colliders. We find that the regions of $g_{hhWW}/g_{hhWW}^{\mathrm{SM}}<0.86$ and $g_{hhWW}/g_{hhWW}^{\mathrm{SM}}>1.32$ can be discovered at the $5\sigma$ confidence level at the 10 TeV ${\mu }^{+}{\mu }^{-}$ collider with an integrated luminosity of 3 ab${}^{-1}$.

   hep-phhep-exPRD(2024)·1 citation
10. 10*

    Determination of CP-violating Higgs couplings with transversely-polarized beams at the ILC

    Cheng Li🇩🇪 · Gudrid Moortgat-Pick🇩🇪

    We study possible CP-violation effects of the Higgs to $Z$-boson coupling at a future $e^{+}{e}^{-}$ collider, e.g. the International Linear Collider (ILC). We find that the azimuthal angular distribution of the muon pair, produced by $e^{+}{e}^{-}\to HZ\to H{\mu }^{+}{\mu }^{-}$, can be sensitive to such a CP-violation effect when we apply initial transversely polarized beams. Based on this angular distribution, we construct a CP sensitive asymmetry and obtain this asymmetry by \texttt{Whizard} simulation. By comparing the SM prediction with 2$\sigma$ range of this asymmetry, we estimate the discovery limit of the CP-odd coupling in $HZZ$ interaction.

    hep-phPoS(2024)·0 citations
11. 11*

    Influence of baryon number, strangeness, and electric charge fluctuations at the LHC

    Christopher Plumberg🇺🇸 · Dekrayat Almaalol🇺🇸 · Travis Dore🇩🇪 · Jordi Salinas San Martin🇺🇸 · Patrick Carzon🇺🇸 · Debora Mroczek🇺🇸 · Nanxi Yao🇺🇸 · Willian M. Serenone🇺🇸 · Lydia Spychalla🇺🇸 · Matthew Sievert🇺🇸 · Jacquelyn Noronha-Hostler🇺🇸

    At the Large Hadron Collider it is possible to generate BSQ (baryon, strangeness, and electric) charge density fluctuations from gluon splittings into quark/anti-quark pairs, generated within the ICCING model. In this work, we implement BSQ charge dynamics in a fully integrated framework. We propagate these conserved charges within an upgraded version of the v-USPhydro hydrodynamic model, which conserves the BSQ densities exactly. Our hydrodynamic simulation uses the full 4D equation of state $\left\{T,{\mu }_B,{\mu }_S,{\mu }_Q\right\}$ from lattice Quantum Chromodynamics and includes decays from the Particle Data Group 2016+. We study the dynamical trajectories of fluid cells passing through the QCD phase diagram. We discuss future applications for this new framework.

    hep-phnucl-exnucl-th5 citations
12. 12*

    Flavon vacuum alignment beyond SUSY

    Claudia Hagedorn🇪🇸 · M.L. López-Ibáñez🇪🇸 · M. Jay Pérez🇺🇸 · Moinul Hossain Rahat🇬🇧 · Oscar Vives🇪🇸

    In flavor models the vacuum alignment of flavons is typically achieved via the $F$-terms of certain fields in the supersymmetric limit. We propose a method for preserving such alignments, up to a rescaling of the vacuum expectation values, even after supersymmetry (and the flavor symmetry) are softly broken, facilitating the vacuum alignment in models which are non-supersymmetric at low energies. Examples of models with different flavor groups, namely $A_4$, $T_7$, $S_4$ and $\Delta (27)$, are discussed.

    hep-phhep-thPRD(2024)·3 citations
13. 13*

    Simplifying QCD event generation with chirality flow, reference vectors and spin directions

    Emil Boman🇸🇪 · Andrew Lifson🇸🇪 · Malin Sjodahl🇸🇪 · Adam Warnerbring🇩🇪 · Zenny Wettersten🇨🇭

    The chirality-flow formalism, combined with good choices of gauge reference vectors, simplifies tree-level calculations to the extent that it is often possible to write down amplitudes corresponding to Feynman diagrams immediately. It has also proven to give a very sizable speedup in a proof of concept implementation of massless tree-level QED in MadGraph5_aMC@NLO. In the present paper we extend this analysis to QCD, including massive quarks. We define helicity-dependent versions of the gluon vertices, derive constraints on the spinor structure of propagating gluons, and explore the Schouten identity to simplify the four-gluon vertex further. For massive quarks, the chirality-flow formalism sheds light on how to exploit the freedom to measure spin along any direction to shorten the calculations. Overall, this results in a clear speedup for treating the Lorentz structure at high multiplicities.

    hep-phJHEP(2024)·4 citations
14. 14*

    Small-x structure of oxygen and neon isotopes as seen by the Large Hadron Collider

    Giuliano Giacalone🇩🇪 · Bjoern Schenke🇺🇸 · Soeren Schlichting🇩🇪 · Pragya Singh🇫🇮

    Results on collisions of ${}^{16}$O nuclei performed at the Relativistic Heavy Ion Collider (RHIC) have been presented for the first time at Quark Matter 2023 by the STAR collaboration. ${}^{16}$O+${}^{16}$O collisions are also expected to take place in the near future at the Large Hadron Collider (LHC) at much higher beam energies. We explore the potential of beam-energy-dependent studies for this system to probe small-$x$ dynamics and QCD evolution. We perform 3+1D IP-Glasma simulations to predict the rapidity dependence of the initial geometry of light-ion collisions, focusing on ${}^{16}$O+${}^{16}$O and ${}^{20}$Ne+${}^{20}$Ne collisions at $\sqrt{s_{\mathrm{NN}}}=70$ GeV and 7 TeV. The choice of ${}^{20}$Ne is motivated by its strongly elongated geometry, which may respond differently to the effect of the high-energy evolution compared to the more spherical ${}^{16}$O. We find that smearing induced by soft gluon production at high energy causes mild variations in the initial-state eccentricities as a function of the collision energy. These effects could be resolved in future experiments and deserve further investigation.

    hep-phnucl-thEPJ Web Conf.(2024)·7 citations
15. 15*

    $S$-wave contribution to rare $D^0\to {\pi }^{+}{\pi }^{-}{\ell }^{+}{\ell }^{-}$ decays in the Standard Model and sensitivity to New Physics

    Svjetlana Fajfer🇸🇮 · Eleftheria Solomonidi🇪🇸 · Luiz Vale Silva🇪🇸

    Physics of the up-type flavour offers unique possibilities of testing the Standard Model (SM) compared to the down-type flavour sector. Here, we discuss SM and New Physics (NP) contributions to the rare charm-meson decay $D^0\to {\pi }^{+}{\pi }^{-}{\ell }^{+}{\ell }^{-}$. In particular, we discuss the effect of including the lightest scalar isoscalar resonance in the SM picture, namely, the $f_0(500)$, which manifests in a big portion of the allowed phase space. Other than showing in the total branching ratio at an observable level of about $20\%$, the $f_0(500)$ resonance manifests as interference terms with the vector resonances, such as at high invariant mass of the leptonic pair in distinct angular observables. Recent data from LHCb optimize the sensitivity to $P$-wave contributions, that we analyse in view of the inclusion of vector resonances. We propose the measurement of alternative observables which are sensitive to the $S$-wave and are straightforward to implement experimentally. This leads to a new set of null observables, that vanish in the SM due to its gauge and flavour structures. Finally, we study observables that depend on the SM interference with generic NP contributions from semi-leptonic four-fermion operators in the presence of the $S$-wave.

    hep-phhep-exPRD(2024)·12 citations
16. 16*

    Introducing Model Benchmark Analysis for dark matter models with isomorphic lagrangians

    Paulo Areyuna C.🇨🇱 · Jilberto Zamora-Saa🇨🇱 · Alfonso R. Zerwekh🇨🇱

    In this work, we propose a novel approach to particle physics phenomenology, which we dubbed as model benchmark analysis. We consider models that provide vertices with similar topology but different Lorentz and gauge structure, which we call isomorphic models. Under this setup, the coupling constants for each theory have the same meaning, in the sense that describe the topologically equivalent diagrams. Consequently, each model acts like a map of parameter space into the observable space. This definition allows to group isomorphic models into families with a common parameter space and perform calculations for each model. As a proof of concept, we obtained some guidelines for the search of leptophilic dark fermions at CLIC, making predictions oriented to discriminate between beyond the standard model scenarios in light of possible signals of new physics that could appear at lepton colliders. We present different observables that can be useful to help discriminating between models.

    hep-ph0 citations
17. 17*

    A cosmological "Big Storm Scenario" following the QCD phase transition

    Edward Shuryak🇺🇸 · Gregory Falkovvich🇮🇱

    It was proposed that acoustic perturbations generated by the QCD phase transition could create an inverse turbulent cascade \cite{Kalaydzhyan:2014wca}. An assumption was that propagation toward smaller momenta could reach the wavelength of a few km, the Universe's size at the time. Such acoustic waves were proposed to be the source of gravity waves. The kilometer wavelength corresponds to year-long gravity wave today, which were recently discovered using pulsar correlations. This paper argues further that an acoustic turbulence must be an ensemble of shocks. This brings two consequences: First, shocks generate gravity waves much more efficiently than sound waves due to the intermittency of matter distribution. We reconsider gravity wave radiation, using universal emission theory for soft radiation, and argue that soft-momenta plateau should reach wavelengths of the order of shock mean free paths. Second, collisions of shock waves create local density excess, which may create primordial black holes. A good tool to settle this issue can be an evaluation of the {\em trapped surfaces} like it was done in studies of heavy ion collisions using AdS/CFT correspondence

    hep-phastro-ph.COJ.Subatomic Part.Cosmol.(2026)·0 citations
18. 18*

    The Quality/Cosmology Tension for a Post-Inflation QCD Axion

    Qianshu Lu🇺🇸 · Matthew Reece🇺🇸 · Zhiquan Sun🇺🇸

    It is difficult to construct a post-inflation QCD axion model that solves the axion quality problem (and hence the Strong CP problem) without introducing a cosmological disaster. In a post-inflation axion model, the axion field value is randomized during the Peccei-Quinn phase transition, and axion domain walls form at the QCD phase transition. We emphasize that the gauge equivalence of all minima of the axion potential (i.e., domain wall number one) is insufficient to solve the cosmological domain wall problem. The axion string on which a domain wall ends must exist as an individual object (as opposed to a multi-string state), and it must be produced in the early universe. These conditions are often not satisfied in concrete models. Post-inflation axion models also face a potential problem from fractionally charged relics; solving this problem often leads to low-energy Landau poles for Standard Model gauge couplings, reintroducing the quality problem. We study several examples, finding that models that solve the quality problem face cosmological problems, and vice versa. This is not a no-go theorem; nonetheless, we argue that it is much more difficult than generally appreciated to find a viable post-inflation QCD axion model. Successful examples may have a nonstandard cosmological history (e.g., multiple types of cosmic axion strings of different tensions), undermining the widespread expectation that the post-inflation QCD axion scenario predicts a unique mass for axion dark matter.

    hep-phhep-thJHEP(2024)·27 citations
19. 19*

    Bjorken $x$ weighted Energy-Energy Correlators from the Target Fragmentation Region to the Current Fragmentation Region

    Haotian Cao🇨🇳 · Hai Tao Li🇨🇳 · Zihao Mi🇨🇳

    We present the complete spectrum for the Bjorken $x$ weighted Energy-Energy Correlation in the deep inelastic scattering (DIS) process, from the target fragmentation region to the current fragmentation region, in the Breit frame. The corresponding collinear and transverse momentum-dependent logarithms are resummed to all orders with the accuracy of NLL and N${}^3$LL, respectively. And the results in the full region are matched with $\mathcal{O}({\alpha }_s^2)$ fixed-order calculation. The final numerical predictions are presented for both EIC and CEBAF kinematics.

    hep-phhep-exnucl-exPRD(2024)·24 citations
20. 20*

    Warm Surprises from Cold Duets: N-Body Simulations with Two-Component Dark Matter

    Jeong Han Kim🇰🇷 · Kyoungchul Kong🇺🇸 · Se Hwan Lim🇰🇷 · Jong-Chul Park🇰🇷

    We explore extensive N-body simulations with two-component cold dark matter candidates. We delve into the temperature evolution, power spectrum, density perturbation, and maximum circular velocity functions. We find that the substantial mass difference between the two candidates and the annihilation of the heavier components to the lighter ones effectively endow the latter with warm dark matter-like behavior, taking advantage of all distinct features that warm dark matter candidates offer, without observational bounds on the warm dark matter mass. Moreover, we demonstrate that the two-component dark matter model aligns well with observational data, providing valuable insights into where and how to search for the elusive dark matter candidates in terrestrial experiments.

    hep-phastro-ph.COastro-ph.HEPTEP(2024)·12 citations
21. 21*

    Combining QED and Approximate N${}^3$LO QCD Corrections in a Global PDF Fit: MSHT20qed_an3lo PDFs

    T. Cridge🇩🇪 · L. A. Harland-Lang🇬🇧 · R.S. Thorne🇬🇧

    We present the MSHT20qed_an3lo parton distribution functions (PDFs). These result from the first global PDF analysis to combine QED and approximate N${}^3$LO (aN${}^3$LO) QCD corrections in the theoretical calculation of the PDF evolution and cross sections entering the fit. We examine the PDF impact, and find that the effect of QED is relatively mild in comparison to the aN${}^3$LO corrections, although it should still be accounted for at the level of precision now required. These QED corrections are in addition found to roughly factorise from the QCD corrections; that is, their relative impact on the PDFs is roughly the same at NNLO and aN${}^3$LO. The fit quality exhibits a very small deterioration at aN${}^3$LO upon the inclusion of QED corrections, which is rather smaller than the deterioration observed at NNLO in QCD. The impact on several cross sections at N${}^3$LO is also examined, including the Higgs cross section via gluon fusion at N${}^3$LO. Finally, a LO in QCD fit that includes QED corrections is also presented: the MSHT20qed_lo set.

    hep-phhep-exSciPost Phys.(2024)·46 citations
22. 22*

    QED-vacuum response and Cherenkov radiated energy in non-linear and Lorentz-symmetry violating scenarios

    Patricio Gaete🇨🇱 · José Abdalla Helayël-Neto🇧🇷

    We investigate physical consequences of non-linear electrodynamic coupled to parameters that signal violation Lorentz-symmetry breaking (LSV). Our undertaking is done by considering a general non-linear photonic Lagrangian which coupled to the Carroll-Field-Jackiw's model (CFJ). Our endeavor reveals how the (meta) material constitutive properties of the vacuum and wave propagation are affected by the interference of the LSV parameters LSV with the specific non-linear electrodynamic model under consideration. We also discuss the refractive indices for this new medium characterized by the coupling between non-linearities and the operators that carry the LSV message. Our results show that the QED-vacuum responds with birefringence and a dispersive propagation of waves. Subsequently, we consider the electromagnetic radiation produced by a moving charged particle interacting with this new medium. Our inspection illustrates that the emitted radiation reproduces the features of the Cherenkov effect for certain intensities of background magnetic fields . Finally, we compute the static potential profile within the framework of the gauge-invariant, but path-dependent, variables formalism. A logarithmic correction to the usual static Coulomb potential emerges driven by the LSV parameter and there also appear corrections due to the non-linearity; nevertheless, the logarithm behavior drops out whenever the LSV parameter is switched off.

    hep-phhep-thEPJC(2024)·2 citations
23. 23*

    Can Primordial Black Holes form in the Standard Model ?

    Ioanna Stamou🇧🇪 · Sebastien Clesse🇧🇪

    We investigate the viability of primordial black hole (PBH) formation in the Standard Model (SM) in a scenario that does not rely on specific inflationary features or any exotic physics such as phase transitions or non-minimal coupling to gravity. If the Brout-Englert-Higgs (BEH) field lies exactly at the transition between metastability and stability, its potential exhibits an inflexion point due to radiative corrections. The BEH can act like a stochastic curvaton field, leading to a non-Gaussian tail of large curvature fluctuations that later collapse into PBHs when they re-enter inside the horizon. This scenario would require a precise value of the top-quark mas to ensure the Higgs stability, which is disfavored but still consistent with the most recent measurements. However, we also find that large curvature fluctuations are also generated on cosmological scales that are inconsistent with cosmic microwave background (CMB) observations. We therefore conclude that the SM cannot have led to the formation of PBHs based on this mechanism. Nevertheless, a variation of the scenario based on the Palatini formulation of gravity may have provided the conditions to produce stellar-mass PBHs with an abundance comparable to dark matter, without producing too large curvature fluctuations on cosmological scales.

    ↳ astro-ph.COhep-phhep-thPRD(2024)·11 citations
24. 24*

    Low-energy limit of N-photon amplitudes in a constant field

    Naser Ahmadiniaz🇩🇪 · Misha A. Lopez-Lopez🇩🇪 · Christian Schubert🇲🇽

    While the QED photon amplitudes at full momentum so far have been calculated only up to the six-photon level, in the low-energy limit there are explicit formulas for all helicity components even at the N-photon level, obtained by Martin et al. in 2002. Here we use the worldline formalism to extend that result to the N-photon amplitudes in a generic constant field. For both scalar and spinor QED, we obtain compact representations for the low-energy limits of these amplitudes involving only simple algebra and a single global proper-time integral with trigonometric integrand.

    ↳ hep-thhep-phPLB(2024)·12 citations
25. 25*

    Evidence of isospin-symmetry violation in high-energy collisions of atomic nuclei: Theoretical and Phenomenological considerations

    Wojciech Brylinski🇵🇱 · Marek Gazdzicki🇵🇱 · Francesco Giacosa🇵🇱 · Mark Gorenstein🇺🇦 · Roman Poberezhnyuk🇺🇦 · Subhasis Samanta🇮🇳

    Recently, the NA61/SHINE collaboration at the CERN SPS reported evidence of isospin-symmetry violation in high-energy nuclear collisions [Nature Commun. 16, 2849 (2025)]. The effect was observed in the relative yields of charged and neutral kaons and cannot be explained by known sources of isospin symmetry breaking. In this work, we extend the theoretical and phenomenological aspects of that study. We discuss the historical background and introduce the concepts of isospin transformations and symmetry. Importantly, we relate isospin symmetry to the QCD flavor symmetry, and we present both conceptual and analytical proofs demonstrating the equality of the mean multiplicities of charged and neutral kaons for an initial ensemble of colliding systems that is invariant under charge-symmetry transformation.

    ↳ nucl-thhep-exhep-phnucl-exActa Phys.Polon.B(2026)·17 citations
26. 26*

    Autoencoder-Driven Clustering of Intersecting D-brane Models via Tadpole Charge

    Keiya Ishiguro🇯🇵 · Satsuki Nishimura🇯🇵 · Hajime Otsuka🇯🇵

    We study the well-known type IIA intersecting D-brane models on the $T^6/({\mathbb{Z}}_2\times {\mathbb{Z}}_2^{\prime })$ orientifold via a machine-learning approach. We apply several autoencoder models with and without positional encoding to the D6-brane configurations satisfying certain concrete models described in arXiv:hep-th/0510170 and attempt to extract some features which the configurations possess. We observe that the configurations cluster in two-dimensional latent layers of the autoencoder models and analyze which physical quantities are relevant to the clustering. As a result, it is found that tadpole charges of hidden D6-branes characterize the clustering. We expect that there is another important factor because a checkerboard pattern in two-dimensional latent layers is observed in the clustering.

    ↳ hep-thhep-phJHEP(2024)·2 citations
27. 27*

    Incoherent processes in dileptons production in proton-nucleus scattering at high energies

    Sergei P. Maydanyuk (1 and 2)🇭🇺 · Gyorgy Wolf (1) ((1) Wigner Research Centre for Physics, Budapest, Hungary, (2) Institute for Nuclear Research, National Academy of Sciences of Ukraine, Kyiv, Ukraine)🇭🇺

    $\mathbf{Purpose}$: Incoherent processes in production of lepton pairs in the scattering of protons off nuclei are investigated. $\mathbf{Methods}$: New quantum mechanical model is constructed which uses generalization of the nuclear model of emission of photons in the proton-nucleus reactions in region from low up to high energies with inclusion of formalism of production of lepton pairs. $\mathbf{Results}$: (1) Model with the coherent matrix elements is tested for the scattering of protons on the Be nuclei at energy of proton beam $E_{\mathrm{p}}$ of 2.1 GeV. The calculated cross section of production of lepton pairs is in good agreement with experimental data obtained by DLS Collaboration. (2) We analyzed dilepton production for nuclei-targets $\text{isotope}[9]Be$, $\text{isotope}[12]C$, $\text{isotope}[16]O$, $\text{isotope}[24]Mg$, $\text{isotope}[44]Ca$, $\text{isotope}[197]Au$ at $E_{\mathrm{p}}=2.1$ GeV. Coherent cross sections of dilepton production are monotonously decreased with increasing of nucleus-target mass. (3) Production of lepton pairs is more intensive at larger $E_{\mathrm{p}}$. (4) For $p+\text{isotope}9Be$ at $E_{\mathrm{p}}=2.1$ GeV we analyzed role of incoherent processes in production of pairs of leptons. Inclusion of incoherent proton-nucleon processes to the model improves agreement with experimental data a little. (5) Adding of the longitudinal amplitude of virtual photon suppresses the cross section of dilepton production a little. (6) The incoherent contribution has a leading role in dilepton production (ratio between incoherent and coherent contributions is 10-100). Model provides the full spectrum for $p+\text{isotope}[93]Nb$ at $E_{\mathrm{p}}=3.5$ GeV in good agreement with experimental data of HADES collaboration, shows large role of incoherent processes. Conclusion: Results above confirms importance of incoherent processes in study of dilepton production in this reaction.

    ↳ nucl-thhep-phnucl-exUniverse(2026)·2 citations
28. 28*

    Acceleration beyond lowest order event generation: An outlook on further parallelism within MadGraph5_aMC@NLO

    Zenny Wettersten🇨🇭 · Olivier Mattelaer🇧🇪 · Stefan Roiser🇨🇭 · Robert Schöfbeck🇦🇹 · Andrea Valassi🇨🇭

    An important area of high energy physics studies at the Large Hadron Collider (LHC) currently concerns the need for more extensive and precise comparison data. Important tools in this realm are event reweighing and evaluation of more precise next-to-leading order (NLO) processes via Monte Carlo event generators, especially in the context of the upcoming High Luminosity LHC. Current event generators need to improve throughputs for these studies. MadGraph5_aMC@NLO (MG5aMC) is an event generator being used by LHC experiments which has been accelerated considerably with a port to GPU and vector CPU architectures, but as of yet only for leading order processes. In this contribution a prototype for event reweighing using the accelerated MG5aMC software, as well as plans for an NLO implementation, are presented.

    ↳ physics.comp-phhep-phEPJ Web Conf.(2024)·9 citations
29. 29*

    A new approach to stochastic relativistic fluid dynamics from information flow

    Nicki Mullins🇺🇸 · Mauricio Hippert🇺🇸 · Lorenzo Gavassino🇺🇸 · Jorge Noronha🇺🇸

    We present a new general formalism for introducing thermal fluctuations in relativistic hydrodynamics, which incorporates recent developments on the causality and stability of relativistic hydrodynamic theories. Our approach is based on the information current, which measures the net amount of information carried by perturbations around equilibrium in a relativistic many-body system. The resulting noise correlators are guaranteed to be observer-independent for thermodynamically stable models. We obtain an effective action within our formalism and discuss its properties.

    ↳ nucl-thhep-phhep-thEPJ Web Conf.(2024)·2 citations
30. 30*

    Probing nuclear structure at the Electron-Ion Collider and in ultra-peripheral nuclear collisions

    Heikki Mäntysaari🇫🇮 · Farid Salazar🇺🇸 · Björn Schenke🇺🇸 · Chun Shen🇺🇸 · Wenbin Zhao🇺🇸

    Within the Color Glass Condensate framework, we demonstrate that exclusive vector meson production at high energy is sensitive to the geometric deformation of the target nucleus and subnucleon scale fluctuations. Deformation of the nucleus enhances the incoherent cross section in the small $|t|$ region. Subnucleon scale fluctuations increase the incoherent cross section in the large $|t|$ region. In ultra-peripheral collisions (UPCs), larger deformation leads to a wider distribution of the minimal impact parameter $B_{min}$ required to produce a UPC. This, together with larger incoherent cross sections for larger deformation, results in smaller extracted radii. Our results demonstrate great potential for future studies of nuclear structure in UPCs and electron-ion collisions.

    ↳ nucl-thhep-phnucl-exEPJ Web Conf.(2024)·4 citations
31. 31*

    A survey of the electroweak configuration space and the W boson mass

    Oswaldo Vazquez🇮🇹

    Following the recent work of V. Moncrief, A. Marini, R. Maitra and P. Mondal on the geometry of field theoretic configuration spaces, this account examines how the regularized Ricci curvature of the $SU(2{)}_L\times U(1{)}_Y$ Yang-Mills orbit space may provide an intrinsic mass to the W boson which contributes to the value obtained from the renormalized Higgs mechanism. Though the discussion is heuristic, one hopes that this infinite-dimensional technology, which does not postulate extensions to the Standard Model, could explain the mass anomaly reported by the CDF II collaboration.

    ↳ hep-thhep-ph0 citations
32. 32*

    Identifying Energy-Dependent Flavor Transitions in High-Energy Astrophysical Neutrino Measurements

    Qinrui Liu🇨🇦 · Damiano F. G. Fiorillo🇩🇰 · Carlos A. Argüelles🇺🇸 · Mauricio Bustamante🇩🇰 · Ningqiang Song🇨🇳 · Aaron C. Vincent🇨🇦

    The flavor composition of TeV--PeV astrophysical neutrinos, i.e., the proportion of neutrinos of different flavors in their flux, is a versatile probe of high-energy astrophysics and fundamental physics. Because flavor identification is challenging and the number of detected high-energy astrophysical neutrinos is limited, so far measurements of the flavor composition have represented an average over the range of observed neutrino energies. Yet, this washes out the potential existence of changes in the flavor composition with energy and weakens our sensitivity to the many models that posit them. For the first time, we measure the energy dependence of the flavor composition, looking for a transition from low to high energies. Our present-day measurements, based on the 7.5-year public sample of IceCube High-Energy Starting Events (HESE), find no evidence of a flavor transition. The observation of HESE and through-going muons jointly by next-generation neutrino telescopes Baikal-GVD, IceCube-Gen2, KM3NeT, P-ONE, TAMBO, and TRIDENT may identify a flavor transition around 200TeV by 2030. By 2040, we could infer the flavor composition with which neutrinos are produced with enough precision to establish the transition from neutrino production via the full pion decay chain at low energies to muon-damped pion decay at high energies.

    ↳ astro-ph.HEhep-phPRD(2025)·18 citations
33. 33*

    Multiparticle Factorization and the Rigidity of String Theory

    Nima Arkani-Hamed🇺🇸 · Clifford Cheung🇺🇸 · Carolina Figueiredo🇺🇸 · Grant N. Remmen🇺🇸

    Is string theory uniquely determined by self-consistency? Causality and unitarity seemingly permit a multitude of putative deformations, at least at the level of two-to-two scattering. Motivated by this question, we initiate a systematic exploration of the constraints on scattering from higher-point factorization, which imposes extraordinarily restrictive sum rules on the residues and spectra defined by a given amplitude. These bounds handily exclude several proposed deformations of the string: the simplest "bespoke" amplitudes with tunable masses and a family of modified string integrands from "binary geometry." While the string itself passes all tests, our formalism directly extracts the three-point amplitudes for the low-lying string modes without the aid of worldsheet vertex operators.

    ↳ hep-thhep-phPRL(2024)·55 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.