Fri·Sep 1, 2023Friday·September 1, 2023

1. 01*

   Medium induced mixing, spatial modulations and critical modes in QCD

   Maximilian Haensch🇩🇪 · Fabian Rennecke🇩🇪 · Lorenz von Smekal🇩🇪

   The mixing between the chiral condensate and the density in hot and dense QCD matter is familiar. We show that the mixing relevant for the ground state is considerably more extensive, and in particular also involves gluonic degrees of freedom. As a result, the Hessian of the QCD effective action is non-Hermitian, but retains a symmetry under combined charge- and complex conjugation. This can lead to complex-conjugate pairs of eigenvalues of this Hessian, signaling regimes with spatially modulated correlations. Furthermore, based on the analytic structure of the quark determinant at a chiral critical point, we demonstrate that the corresponding massless critical mode is composed of the chiral condensate, the density and the Polyakov loops. Due to an avoided crossing, the critical mode turns out to be disconnected from the chiral condensate in vacuum. We present general arguments for all these features and illustrate them through explicit model calculations.

   hep-phhep-thnucl-thPRD(2024)·30 citations
2. 02*

   Schwinger displacement of the quark-gluon vertex

   A. C. Aguilar🇧🇷 · M .N. Ferreira🇪🇸 · D. Ibañez🇪🇸 · J. Papavassiliou🇪🇸

   The action of the Schwinger mechanism in pure Yang-Mills theories endows gluons with an effective mass, and, at the same time, induces a measurable displacement to the Ward identity satisfied by the three-gluon vertex. In the present work we turn to Quantum Chromodynamics with two light quark flavors, and explore the appearance of this characteristic displacement at the level of the quark-gluon vertex. When the Schwinger mechanism is activated, this vertex acquires massless poles, whose momentum-dependent residues are determined by a set of coupled integral equations. The main effect of these residues is to displace the Ward identity obeyed by the pole-free part of the vertex, causing modifications to its form factors, and especially the one associated with the tree-level tensor. The comparison between the available lattice data for this form factor and the Ward identity prediction reveals a marked deviation, which is completely compatible with the theoretical expectation for the attendant residue. This analysis corroborates further the self-consistency of this mass-generating scenario in the general context of real-world strong interactions.

   hep-phhep-lathep-thnucl-thEPJC(2023)·15 citations
3. 03*

   Dark phase transition from WIMP: complementary tests from gravitational waves and colliders

   Shinya Kanemura🇯🇵 · Shao-Ping Li🇨🇳

   A dark sector is an interesting place where a strong first-order phase transition, observable gravitational waves and/or a dark matter candidate could arise. However, the experimental tests for such a dark sector could be ambiguous due to the dark content, largely unconstrained parameter space and the connection to the visible world. We consider a minimal dark scalar-vector boson plasma to realize the three mentioned phenomena, with a unique connection to the Standard Model via the Higgs portal coupling. We discuss the important features of the Higgs portal in such a minimal dark sector, namely the dark thermalization, collider tests, and direct detection of dark matter. We perform numerical analyses of the dark phase transition associated with stochastic gravitational waves and dark matter, discussing the complementarity of collider detection, dark matter direct detection and space-based/terrestrial interferometers as a promising avenue to hear and see the minimal dark sector.

   hep-phJCAP(2024)·17 citations
4. 04*

   Instantaneous Symmetry Breaking to the Non-observed Dark Matter

   Yaquan Fang🇨🇳

   A theory explaining the non-observation of the dark matter and the source of the dark energy is presented in this letter. By integrating the asymmetrical potential and the Higgs potential, we provide a model with instantaneous symmetrical breaking and stable symmetrical breaking, resulting in the non-observed dark matter and observed matter respectively. Two crucial parameters in this model are the frequency and strength of the symmetry breaking from the vacuum: the former helps explain the impact of the effective mass from the dark matter; the latter determines the source of the dark energy. The expected strength in a certain period varies, causing the accelerating or deccelerating expansions of the universe. Considering the expected strength correlated with the vacuum expectation value and basing on the possible variations of the measured masses of the fundamental particles such as Z boson over time, one can perhaps derive the exact stage of the current universe.

   hep-ph0 citations
5. 05*

   QCD factorization for the $B\to \gamma \ell {\nu }_{\ell }$ decay beyond leading power

   Bo-Yan Cui🇨🇳 · Yue-Long Shen🇨🇳 · Chao Wang🇨🇳 · Yan-Bing Wei🇨🇳

   The radiative leptonic $B\to \gamma \ell {\nu }_{\ell }$ decay serves as an ideal platform to determine the $B$-meson inverse moment which is a fundamental nonperturbative parameter for the $B$ meson. In this paper, we explore precise QCD contributions to this decay with an energetic photon. We reproduce the next-to-next-to-leading-logarithmic resummation formula for the decay amplitude at leading power in ${\Lambda }_{\mathrm{QCD}}/m_b$. Employing operator identities, we calculate subleading-power contributions from the expansion of the hard-collinear propagator of the internal up quark and the heavy-quark expansion of the bottom quark. We update the contributions from the hadronic structure of the photon to the $\text{decay}$ process with the dispersion technique. Together with other yet known power corrections, phenomenological applications including the partial branching fraction and ratio of the branching fractions of the radiative $B$ decay are investigated.

   hep-phEPJC(2025)·9 citations
6. 06*

   Probing the dipole portal to heavy neutral leptons via meson decays at the high-luminosity LHC

   Daniele Barducci🇮🇹 · Wei Liu🇨🇳 · Arsenii Titov🇮🇹 · Zeren Simon Wang🇹🇼 · Yu Zhang🇨🇳

   We consider the dipole portal to sterile neutrinos, also called heavy neutral leptons (HNLs). The dipole interaction with the photon leads to HNL production in meson decays, as well as triggers the HNL decay into an active neutrino and a photon. HNLs with masses of order of 0.01-1 GeV are naturally long-lived if the dipole coupling is sufficiently small. We perform Monte-Carlo simulations and derive the sensitivities of the proposed FASER2 and FACET long-lived particle experiments to HNLs produced via the dipole operator in meson decays at the high-luminosity LHC. Our findings show that these future detectors will be complementary to each other, as well as to existing experiments, and will be able to probe new parts of the parameter space, especially in the case of the dipole operator coupled to the tau neutrino.

   hep-phhep-exPRD(2023)·25 citations
7. 07*

   Revisit spin effects induced by thermal vorticity

   Jian-Hua Gao🇨🇳 · Shi-Zheng Yang🇨🇳

   We revisit the spin effects induced by thermal vorticity by calculating them directly from the spin-dependent distribution functions. For the spin-1/2 particles, we give the polarization up to the first order of thermal vorticity and compare it with the usual result calculated from the spin vector. For the spin-1 particles, we find that all the non-diagonal elements vanish and there is no spin alignment up the first order of thermal vortcity. We present the spin alignment at second-order contribution from thermal vorticity. We also find that the spin effects for both Dirac and vector particles will receive extra contribution when the spin direction is associated with the particle's momentum.

   hep-phhep-thnucl-thCPC(2024)·5 citations
8. 08*

   Effects of the $\alpha$-cluster structure and the intrinsic momentum component of nuclei on the longitudinal asymmetry in relativistic heavy-ion collisions

   Ru-XIn Cao🇨🇳 · Song Zhang🇨🇳 · Yu-Gang Ma🇨🇳

   The longitudinal asymmetry in relativistic heavy ion collisions arises from the fluctuation in the number of nucleons involved. This asymmetry causes a rapidity shift in the center of mass of the participating zone. Both the rapidity shift and the longitudinal asymmetry have been found to be significant at the top CERN Large Hadron Collider (LHC) energy for collisions of identical nuclei, and the longitudinal asymmetry is important for reconstructing the colliding vertex and correcting the rapidity shift. However, much discussion of the longitudinal asymmetry has treated the initial condition as a nonzero momentum contributed only by the number of participants, i.e., the asymmetry depends only on the number of participating nucleons. So we naturally raise a physical problem, can other initial conditions, such as two typical initial conditions for nuclei, geometric configuration, and momentum distribution, provide effects on the longitudinal asymmetry? Therefore, in this work we consider other effects on the longitudinal asymmetry other than the fluctuation in the number of participants, e.g., the {\alpha} clustering structure as well as the intrinsic momentum distribution in the target and projectile nuclei for the collisions in the framework of a multiphase transport (AMPT) model. By introducing systems with different {\alpha}-clustering structure and intrinsic momentum distribution, we calculated the ratio of the rapidity distributions of different systems and extracted expansion coefficients to analyze the difference contributed by these factors. ...

   hep-phnucl-thPRC(2023)·9 citations
9. 09*

   Like-Sign W-Boson Scattering at the LHC -- Approximations and Full Next-to-Leading-Order Predictions

   Stefan Dittmaier🇩🇪 · Philipp Maierhöfer🇩🇪 · Christopher Schwan🇩🇪 · Ramon Winterhalder🇧🇪

   We present a new calculation of next-to-leading-order corrections of the strong and electroweak interactions to like-sign W-boson scattering at the Large Hadron Collider, implemented in the Monte Carlo integrator Bonsay. The calculation includes leptonic decays of the $\mathrm{W}$ bosons. It comprises the whole tower of next-to-leading-order contributions to the cross section, which scale like ${\alpha }_{\mathrm{s}}^3{\alpha }^4$, ${\alpha }_{\mathrm{s}}^2{\alpha }^5$, ${\alpha }_{\mathrm{s}}{\alpha }^6$, and ${\alpha }^7$ in the strong and electroweak couplings ${\alpha }_{\mathrm{s}}$ and $\alpha$. We present a detailed survey of numerical results confirming the occurrence of large pure electroweak corrections of the order of $\sim -12\%$ for integrated cross sections and even larger corrections in high-energy tails of distributions. The electroweak corrections account for the major part of the complete next-to-leading-order correction, which amounts to $15-20\%$ in size, depending on the details of the event selection chosen for analysing vector-boson-scattering. Moreover, we compare the full next-to-leading-order corrections to approximate results based on the neglect of contributions that are not enhanced by the vector-boson scattering kinematics (VBS approximation) and on resonance expansions for the $\mathrm{W}$-boson decays (double-pole approximation); the quality of this approximation is good within $\sim 1.5\%$ for integrated cross sections and the dominating parts of the differential distributions. Finally, for the leading-order predictions, we construct different versions of effective vector-boson approximations, which are based on cross-section contributions that are enhanced by collinear emission of $\mathrm{W}$ bosons off the initial-state (anti)quarks; in line with previous findings in the literature, it turns out that the approximative quality is rather limited for applications at the LHC.

   hep-phJHEP(2023)·16 citations
10. 10*

    Mapping properties of the quark gluon plasma in Pb-Pb and Xe-Xe collisions at energies available at the CERN Large Hadron Collider

    L. Vermunt🇩🇪 · Y. Seemann🇩🇪 · A. Dubla🇩🇪 · S. Floerchinger🇩🇪 · E. Grossi🇮🇹 · A. Kirchner🇹🇼 · S. Masciocchi🇩🇪 · I. Selyuzhenkov🇩🇪

    A phenomenological analysis of the experimental measurements of transverse momentum spectra of identified charged hadrons and strange hyperons in Pb-Pb and Xe-Xe collisions at the LHC is presented. The analysis is based on the relativistic fluid dynamics description implemented in the numerically efficient \textsc{Fluid{\it u}M} approach. Building on our previous work, we separate in our treatment the chemical and kinetic freeze-out, and incorporate the partial chemical equilibrium to describe the late stages of the collision evolution. This analysis makes use of Bayesian inference to determine key parameters of the QGP evolution and its properties including the shear and bulk viscosity to entropy ratios, the initialisation time, the initial entropy density, and the freeze-out temperatures. The physics parameters and their posterior probabilities are extracted using a global search in multidimensional space with modern machine learning tools, such as ensembles of neural networks. We employ our newly developed fast framework to assess systematic uncertainties in the extracted model parameters by systematically varying key components of our analysis.

    hep-phPRC(2023)·11 citations
11. 11*

    Hybrid Renormalization for Quasi Distribution Amplitudes of A Light Baryon

    Chao Han🇨🇳 · Yushan Su🇺🇸 · Wei Wang🇨🇳 · Jia-Lu Zhang🇨🇳

    We develop a hybrid scheme to renormalize quasi distribution amplitudes of a light baryon on the lattice, which combines the self-renormalization and ratio scheme. By employing self-renormalization, the UV divergences and linear divergence at large spatial separations in quasi distribution amplitudes are removed without introducing extra nonperturbative effects, while making a ratio with respect to the zero-momentum matrix element can properly remove the UV divergences in small spatial separations. As a specific application, distribution amplitudes of the $\Lambda$ baryon made of $uds$ are investigated, and the requisite equal-time correlators, which define quasi distribution amplitudes in coordinate space, are perturbatively calculated up to the next-to-leading order in strong coupling constant ${\alpha }_s$. These perturbative equal-time correlators are used to convert lattice QCD matrix elements to the continuum space during the renormalization process. Subsequently, quasi distribution amplitudes are matched onto lightcone distribution amplitudes by integrating out hard modes and the corresponding hard kernels are derived up to next-to-leading order in ${\alpha }_s$ including the hybrid counterterms. These results are valuable in the lattice-based investigation of the lightcone distribution amplitudes of a light baryon from the first principles of QCD.

    hep-phhep-latnucl-thJHEP(2023)·25 citations
12. 12*

    Resonance contributions to nucleon spin structure in Holographic QCD

    Francesco Bigazzi🇮🇹 · Federico Castellani🇮🇹

    We study polarized inelastic electron-nucleon scattering at low momentum transfer in the Witten-Sakai-Sugimoto model of holographic QCD, focusing on resonance production contributions to the nucleon spin structure functions. Our analysis includes both spin $3/2$ and spin $1/2$ low-lying nucleon resonances with positive and negative parity. We determine, in turn, the helicity amplitudes for nucleon-resonance transitions and the resonance contributions to the neutron and proton generalized spin polarizabilities. Extrapolating the model parameters to realistic QCD data, our analysis, triggered by recent experimental results from Jefferson Lab, agrees with the observation that the $\Delta (1232)$ resonance gives the dominant contribution to the forward spin polarizabilities at low momentum transfer. The contribution is negative and tends to zero as the momentum transfer increases. As expected, the contribution of the $\Delta (1232)$ to the longitudinal-transverse polarizabilities is instead negligible. The latter, for both nucleons, turn out the be negative functions with zero asymptote. The holographic results, at least for the proton where enough data are available, are in qualitative agreement with the resonance contributions to the spin polarizabilities extracted from experimental data on the helicity amplitudes.

    hep-phhep-thnucl-thJHEP(2024)·6 citations
13. 13*

    Probing Neutral Triple Gauge Couplings with $Z^{\ast }\gamma (\nu \bar{\nu }\gamma )$ Production at Hadron Colliders

    John Ellis🇬🇧 · Hong-Jian He🇨🇳 · Rui-Qing Xiao🇬🇧

    We study probes of neutral triple gauge couplings (nTGCs) via $Z^{\ast }\gamma$ production followed by off-shell decays $Z^{\ast }\to \nu \bar{\nu }$ at the LHC and future $pp$ colliders, including both CP-conserving (CPC) and CP-violating (CPV) couplings. We present the dimension-8 SMEFT operators contributing to nTGCs and derive the correct form factor formulation for the off-shell vertices $Z^{\ast }\gamma V^{\ast }$ ($V=Z,\gamma$) by matching them with the dimension-8 SMEFT operators. Our analysis includes new contributions enhanced by the large off-shell momentum of $Z^{\ast }$, beyond those of the conventional $Z\gamma V^{\ast }$ vertices with on-shell $Z\gamma$. We analyze the sensitivity reaches for probing the CPC/CPV nTGC form factors and the new physics scales of the dimension-8 nTGC operators at the LHC and future 100TeV $pp$ colliders. We compare our new predictions with the existing LHC measurements of CPC nTGCs in the $\nu \bar{\nu }\gamma$ channel and demonstrate the importance of our new method.

    hep-phhep-exPRD(2023)·30 citations
14. 14*

    Distinguishing models with $\mu \to e$ observables

    Marco Ardu🇫🇷 · Sacha Davidson🇫🇷 · Stéphane Lavignac🇫🇷

    Upcoming experiments will improve the reach for the lepton flavour violating (LFV) processes $\mu \to e\gamma$, $\mu \to e\bar{e}e$ and $\mu A\to eA$ by orders of magnitude. We investigate whether this upcoming data could rule out some popular TeV-scale LFV models (the type II seesaw, the inverse seesaw and a scalar leptoquark) using a bottom-up EFT approach involving twelve Wilson coefficients that can in principle all be determined by experimental measurements. In this 12-dimensional coefficient space, each model can only predict points in a specific subspace; for instance, flavour change involving singlet electrons is suppressed in the seesaw models, and the leptoquark induces negligible coefficients for 4-lepton scalar operators. Using the fact that none of these models can populate the whole region accessible to upcoming experiments, we show that $\mu \to e$ experiments have the ability to rule them out.

    hep-phJHEP(2023)·21 citations
15. 15*

    Eclectic flavor group $\Delta (27)⋊S_3$ and lepton model building

    Cai-Chang Li🇨🇳 · Gui-Jun Ding🇨🇳

    We have performed a systematical study of the eclectic flavor group $\Delta (27)⋊S_3$ which is the extension of the traditional flavor symmetry $\Delta (27)$ by the finite modular symmetry $S_3$. Consistency between $\Delta (27)$ and $S_3$ requires that the eight nontrivial singlet representations of $\Delta (27)$ should be arranged into four reducible doublets. The modular transformation matrices are determined for various $\Delta (27)$ multiplets, and the CP-like symmetry compatible with $\Delta (27)⋊S_3$ are discussed. We study the general form of the Kähler potential and superpotential invariant under $\Delta (27)⋊S_3$, and the corresponding fermion mass matrices are presented. We propose a bottom-up model for lepton masses and mixing based on $\Delta (27)⋊S_3$, a numerical analysis is performed and the experimental data can be accommodated.

    hep-phJHEP(2024)·15 citations
16. 16*

    $K^{\pm }\to {\pi }^{\pm }a$ at Next-to-Leading Order in Chiral Perturbation Theory and Updated Bounds on ALP Couplings

    Claudia Cornella🇩🇪 · Anne Mareike Galda🇩🇪 · Matthias Neubert🇺🇸 · Daniel Wyler🇨🇭

    The weak decays $K^{\pm }\to {\pi }^{\pm }a$ offer a powerful probe of axion-like particles (ALPs). In this work, we provide a comprehensive analysis of these processes within chiral perturbation theory, extending existing calculations by including complete next-to-leading order (NLO) contributions and isospin-breaking corrections at first order in $(m_d-m_u)$. We show that the consistent incorporation of ALPs in the QCD and weak chiral Lagrangians requires a non-trivial extension of the corresponding operator bases, which we describe in detail. Furthermore, we show that in the presence of an ALP the so-called ``weak mass term'', which is unobservable in the Standard Model, is non-redundant already at leading order. We find that NLO corrections associated with flavor-violating ALP couplings modify the leading-order result by a few percent, with negligible uncertainties. NLO corrections proportional to flavor-conserving ALP couplings lead to potentially larger corrections, which, however, are accompanied by sizable uncertainties mainly due to the currently limited knowledge of various low-energy constants. We study how these corrections impact bounds on the ALP couplings, first model independently, and then specializing to the case of an ALP with flavor-universal couplings in the UV. Our findings confirm that the decays $K^{\pm }\to {\pi }^{\pm }a$ provide the strongest particle-physics constraints for $m_a\lesssim 300$\,MeV. In addition, we point out that these bounds have interesting implications for the ALP couplings to nucleons, which were so far only constrained by astrophysical measurements and non-accelerator experiments.

    hep-phJHEP(2024)·23 citations
17. 17*

    Master Integrals for Four-Loop Massless Form Factors

    Roman N. Lee🇷🇺 · Andreas von Manteuffel🇩🇪 · Robert M. Schabinger🇺🇸 · Alexander V. Smirnov🇷🇺 · Vladimir A. Smirnov🇷🇺 · Matthias Steinhauser🇩🇪

    We present analytical results for all master integrals for massless three-point functions, with one off-shell leg, at four loops. Our solutions were obtained using differential equations and direct integration techniques. We review the methods and provide additional details.

    hep-phhep-thEPJC(2023)·9 citations
18. 18*

    Bayesian questions with frequentist answers

    Alan H. Guth🇺🇸 · Mohammad Hossein Namjoo🇮🇷

    The two statistical methods, namely the frequentist and the Bayesian methods, are both commonly used for probabilistic inference in many scientific situations. However, it is not straightforward to interpret the result of one approach in terms of the concepts of the other. In this paper we explore the possibility of finding a Bayesian significance for the frequentist's main object of interest, the $p$-value, which is the probability assigned to the proposition -- which we call the {\it extremity proposition} -- that a measurement will result in a value that is at least as extreme as the value that was actually obtained. To make contact with the frequentist language, the Bayesian can choose to update probabilities based on the {\it extremity proposition}, which is weaker than the standard Bayesian update proposition, which uses the actual observed value. We then show that the posterior probability (or probability density) of a theory is equal to the prior probability (or probability density) multiplied by the ratio of the $p$-value for the data obtained, given that theory, to the mean $p$-value -- averaged over all theories weighted by their prior probabilities. Thus, we provide frequentist answers to Bayesian questions. Our result is generic -- it does not rely on restrictive assumptions about the situation under consideration or specific properties of the likelihoods or the priors.

    ↳ physics.data-anastro-ph.COgr-qchep-ph+20 citations
19. 19*

    Does the Cosmological Constant really indicate the existence of a Dark Dimension?

    Carlo Branchina🇰🇷 · Vincenzo Branchina🇮🇹 · Filippo Contino🇮🇹 · Arcangelo Pernace🇮🇹

    According to the "dark dimension" (DD) scenario, we might live in a universe with a single compact extra dimension, whose mesoscopic size is dictated by the measured value of the cosmological constant. This scenario is based on swampland conjectures, that lead to the relation ${\rho }_{\mathrm{swamp}}\sim m_{{}_{\mathrm{KK}}}^4$ between the vacuum energy ${\rho }_{\mathrm{swamp}}$ and the size of the extra dimension $m_{{}_{\mathrm{KK}}}^{-1}$ ($m_{{}_{\mathrm{KK}}}$ is the mass scale of a Kaluza-Klein tower), and on the corresponding result ${\rho }_{{}_{\mathrm{EFT}}}$ from the EFT limit. We show that ${\rho }_{{}_{\mathrm{EFT}}}$ contains previously missed UV-sensitive terms, whose presence invalidates the widely spread belief (based on existing literature) that the calculation gives automatically the finite result ${\rho }_{{}_{\mathrm{EFT}}}\sim m_{{}_{\mathrm{KK}}}^4$ (with no need for fine-tuning). This renders the matching between ${\rho }_{\mathrm{swamp}}$ and ${\rho }_{{}_{\mathrm{EFT}}}$ a non-trivial issue. We then comment on the necessity to find a mechanism that implements the suppression of the aforementioned UV-sensitive terms. This should finally allow to frame the DD scenario in a self-consistent framework, also in view of its several phenomenological applications based on EFT calculations.

    ↳ hep-thgr-qchep-phInt.J.Geom.Meth.Mod.Phys.(2025)·17 citations
20. 20*

    Un-screened forces in Quark-Gluon Plasma?

    Alexei Bazavov🇺🇸 · Daniel Hoying🇨🇭 · Rasmus N. Larsen🇳🇴 · Swagato Mukherjee🇺🇸 · Peter Petreczky🇺🇸 · Alexander Rothkopf🇳🇴 · Johannes Heinrich Weber🇩🇪

    We study the correlator of temporal Wilson lines at non-zero temperature in 2+1 flavor lattice QCD with the aim to define the heavy quark-antiquark potential at non-zero temperature. For temperatures $153\mathrm{MeV}\le T\le 352\mathrm{MeV}$ the spectral representation of this correlator is consistent with a broadened peak in the spectral function, position or width of which then defines the real or imaginary parts of the heavy quark-antiquark potential at non-zero temperature, respectively. We find that the potential's real part is not screened contrary to the widely-held expectations. We comment on how this fact may modify the picture of quarkonium melting in the quark-gluon plasma.

    ↳ hep-lathep-phnucl-thPRD(2024)·53 citations
21. 21*

    The nuclear liquid-gas transition in QCD

    Kenji Fukushima🇯🇵 · Jan Horak🇩🇪 · Jan M. Pawlowski🇩🇪 · Nicolas Wink🇩🇪 · Carl Philipp Zelle🇩🇪

    We estimate the nuclear saturation density and the binding energy in a nuclear liquid from precision data on the coupling of the four-quark scattering vertex in the vector channel, computed within functional QCD. We show that this coupling is directly related to the density-density potential and the latter is used for the estimates. In a first qualitative computation we find a saturation density of 0.2 fm${}^{-3}$ and an upper bound for the binding energy of 21.5 MeV, in agreement with the empirical values of 0.16 fm${}^{-3}$ and 16 MeV, respectively. We also use the scattering vertex for constructing an emergent low-energy effective theory for the liquid gas transition from QCD correlation function, whose coupling parameters can be determined within QCD. As a first consistency check of this construction we estimate the in-medium reduction of the nucleon pole mass.

    ↳ nucl-thhep-phPRD(2024)·12 citations
22. 22*

    Seven hints that early-time new physics alone is not sufficient to solve the Hubble tension

    Sunny Vagnozzi🇮🇹

    The Hubble tension has now grown to a level of significance which can no longer be ignored and calls for a solution which, despite a huge number of attempts, has so far eluded us. Significant efforts in the literature have focused on early-time modifications of $\Lambda$CDM, introducing new physics operating prior to recombination and reducing the sound horizon. In this opinion paper I argue that early-time new physics alone will always fall short of fully solving the Hubble tension. I base my arguments on seven independent hints, related to 1) the ages of the oldest astrophysical objects, 2) considerations on the sound horizon-Hubble constant degeneracy directions in cosmological data, 3) the important role of cosmic chronometers, 4) a number of ``descending trends'' observed in a wide variety of low-redshift datasets, 5) the early integrated Sachs-Wolfe effect as an early-time consistency test of $\Lambda$CDM, 6) early-Universe physics insensitive and uncalibrated cosmic standard constraints on the matter density, and finally 7) equality wavenumber-based constraints on the Hubble constant from galaxy power spectrum measurements. I argue that a promising way forward should ultimately involve a combination of early- and late-time (but non-local -- in a cosmological sense, i.e. at high redshift) new physics, as well as local (i.e. at $z\sim 0$) new physics, and I conclude by providing reflections with regards to potentially interesting models which may also help with the $S_8$ tension.

    ↳ astro-ph.COgr-qchep-phhep-thUniverse(2023)·416 citations
23. 23*

    21cm signal sensitivity to dark matter decay

    Gaétan Facchinetti🇧🇪 · Laura Lopez-Honorez🇧🇪 · Yuxiang Qin🇦🇺 · Andrei Mesinger🇮🇹

    The redshifted 21cm signal from the Cosmic Dawn is expected to provide unprecedented insights into early Universe astrophysics and cosmology. Here we explore how dark matter can heat the intergalactic medium before the first galaxies, leaving a distinctive imprint in the 21cm power spectrum. We provide the first dedicated Fisher matrix forecasts on the sensitivity of the Hydrogen Epoch of Reionization Array (HERA) telescope to dark matter decays. We show that with 1000 hours of observation, HERA has the potential to improve current cosmological constraints on the dark matter decay lifetime by up to three orders of magnitude. Even in extreme scenarios with strong X-ray emission from early-forming, metal-free galaxies, the bounds on the decay lifetime would be improved by up to two orders of magnitude. Overall, HERA shall improve on existing limits for dark matter masses below $2$ GeV$/c^2$ for decays into $e^{+}{e}^{-}$ and below few MeV$/c^2$ for decays into photons.

    ↳ astro-ph.COastro-ph.GAhep-phJCAP(2024)·39 citations
24. 24*

    Quasinormal Modes of C-metric from SCFTs

    Yang Lei🇨🇳 · Hongfei Shu🇨🇳 · Kilar Zhang🇨🇳 · Rui-Dong Zhu🇨🇳

    We study the quasinormal modes (QNM) of the charged C-metric, which physically stands for a charged accelerating black hole, with the help of Nekrasov's partition function of 4d $\mathcal{N}=2$ superconformal field theories (SCFTs). The QNM in the charged C-metric are classified into three types: the photon-surface modes, the accelerating modes and the near-extremal modes, and it is curious how the single quantization condition proposed in arXiv:2006.06111 can reproduce all the different families. We show that the connection formula encoded in terms of Nekrasov's partition function captures all these families of QNM numerically and recovers the asymptotic behavior of the accelerating and the near-extremal modes analytically. Using the connection formulae of different 4d $\mathcal{N}=2$ SCFTs, one can solve both the radial and the angular part of the scalar perturbation equation respectively. The same algorithm can be applied to the de Sitter (dS) black holes to calculate both the dS modes and the photon-sphere modes.

    ↳ hep-thastro-ph.HEgr-qchep-ph+2JHEP(2024)·31 citations
25. 25*

    Branches of a Tree: Taking Derivatives of Programs with Discrete and Branching Randomness in High Energy Physics

    Michael Kagan🇺🇸 · Lukas Heinrich🇩🇪

    We propose to apply several gradient estimation techniques to enable the differentiation of programs with discrete randomness in High Energy Physics. Such programs are common in High Energy Physics due to the presence of branching processes and clustering-based analysis. Thus differentiating such programs can open the way for gradient based optimization in the context of detector design optimization, simulator tuning, or data analysis and reconstruction optimization. We discuss several possible gradient estimation strategies, including the recent Stochastic AD method, and compare them in simplified detector design experiments. In doing so we develop, to the best of our knowledge, the first fully differentiable branching program.

    ↳ stat.MLcs.LGhep-exhep-ph+112 citations
26. 26*

    Lattice QCD Calculation of Electroweak Box Contributions to Superallowed Nuclear and Neutron Beta Decays

    Peng-Xiang Ma🇨🇳 · Xu Feng🇨🇳 · Mikhail Gorchtein🇩🇪 · Lu-Chang Jin🇺🇸 · Keh-Fei Liu🇺🇸 · Chien-Yeah Seng🇺🇸 · Bi-Geng Wang🇺🇸 · Zhao-Long Zhang🇨🇳

    We present the first lattice QCD calculation of the universal axial $\gamma W$-box contribution ${\square }_{\gamma W}^{VA}$ to both superallowed nuclear and neutron beta decays. This contribution emerges as a significant component within the theoretical uncertainties surrounding the extraction of $|V_{ud}|$ from superallowed decays. Our calculation is conducted using two domain wall fermion ensembles at the physical pion mass. To construct the nucleon 4-point correlation functions, we employ the random sparsening field technique. Furthermore, we incorporate long-distance contributions to the hadronic function using the infinite-volume reconstruction method. Upon performing the continuum extrapolation, we arrive at ${\square }_{\gamma W}^{VA}=3.65(8{)}_{\mathrm{lat}}(1{)}_{\mathrm{PT}}\times 10^{-3}$. Consequently, this yields a slightly higher value of $|V_{ud}|=0.97386(11{)}_{exp.}(9{)}_{\mathrm{RC}}(27{)}_{\mathrm{NS}}$, reducing the previous $2.1\sigma$ tension with the CKM unitarity to $1.8\sigma$. Additionally, we calculate the vector $\gamma W$-box contribution to the axial charge $g_A$, denoted as ${\square }_{\gamma W}^{VV}$, and explore its potential implications.

    ↳ hep-lathep-phnucl-exPRL(2024)·51 citations
27. 27*

    Neutron Star vs Quark Star in the Multimessenger Era

    Zheng Cao🇨🇳 · Lie-Wen Chen🇨🇳

    Neutron stars (NSs) which could contain exotic degrees of freedom in the core and the self-bound quark stars (QSs) made purely of absolutely stable deconfined quark matter are still two main candidates for the compact objects observed in pulsars and gravitational wave (GW) events in binary star mergers. We perform a Bayesian model-agnostic inference of the properties of NSs and QSs by combining multi-messenger data of GW170817, GW190425, PSR J0030+0451, PSR J0740+6620, PSR J1614-2230, PSR J0348+0432 as well as ab initio calculations from perturbative quantum chromodynamics and chiral effective field theory. We find the NS scenario is strongly favored against the QS scenario with a Bayes factor of NS over QS ${\mathcal{B}}_{\text{QS}}^{\text{NS}}=11.5$. In addition, the peak of the squared sound velocity $c_s^2\sim 0.5c^2$ around $3.5$ times nuclear saturation density $n_0$ observed in the NS case disappears in the QS case which suggests that the $c_s^2$ first increases and then saturates at $c_s^2\sim 0.5c^2$ above $\sim 4n_0$. The sound velocity and trace anomaly are found to approach the conformal limit in the core of heavy NSs with mass $M\gtrsim 2M_{\odot }$, but not in the core of QSs.

    ↳ astro-ph.HEhep-phnucl-exnucl-th14 citations
28. 28*

    Holography of Broken U(1) Symmetry

    Ian Chaffey🇺🇸 · Sylvain Fichet🇧🇷 · Philip Tanedo🇺🇸

    We examine the Abelian Higgs model in (d+1)-dimensional anti-de Sitter space with an ultraviolet brane. The gauge symmetry is broken by a bulk Higgs vacuum expectation value triggered on the brane. We propose two separate Goldstone boson equivalence theorems for the boundary and bulk degrees of freedom. We compute the holographic self-energy of the gauge field and show that its spectrum is either a continuum, gapped continuum, or a discretuum as a function of the Higgs bulk mass. When the Higgs has no bulk mass, the AdS isometries are unbroken. We find in that case that the dual CFT has a non-conserved U(1) current whose anomalous dimension is proportional to the square of the Higgs vacuum expectation value. When the Higgs background weakly breaks the AdS isometries, we present an adapted WKB method to solve the gauge field equations. We show that the U(1) current dimension runs logarithmically with the energy scale in accordance with a nearly-marginal U(1)-breaking deformation of the CFT.

    ↳ hep-thhep-phJHEP(2024)·7 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.