Mon·Sep 4, 2023Monday·September 4, 2023

1. 01*

   Naturalness-motivated composite Higgs model for generating the top Yukawa coupling

   Yi Chung🇩🇪

   The large top Yukawa coupling results in the top quark contributing significantly to the quantum correction of the Higgs mass term. Traditionally, this effect is canceled by the presence of top partners in symmetry-based models. However, the absence of light top partners poses a challenge to the Naturalness of these models. In this paper, we study a model based on composite Higgs with the top Yukawa coupling originating from dimension-six four-fermion operators. The low cutoff scale of the top quark loop required by the Naturalness principle can be realized with a light gauge boson $E_{\mu }$ which connects the hyperfermions and top quarks. A scalar-less dynamical model with weakly coupled extended $SU(4{)}_{EC}$ gauge group is presented. The model features an $E_{\mu }$ boson and a $Z_E^{\prime }$ boson both at the sub-TeV scale, which lead to a rich phenomenology, especially in the top physics.

   hep-phPRD(2024)·11 citations
2. 02*

   Implications of an enhanced $B\to K\nu \bar{\nu }$ branching ratio

   Rigo Bause🇩🇪 · Hector Gisbert🇮🇹 · Gudrun Hiller🇩🇪

   Rare decays mediated by $b\to s\nu \bar{\nu }$ transitions have been reported by the Belle II experiment. The branching ratio of the decay $B^{+}\to K^{+}\nu \bar{\nu }$ is found to be enhanced with respect to the standard model value. If taken at face value, the implications are profound: either lepton flavor universality is violated at the (multi)-TeV-scale, or light new physics is involved. This holds in general if $\mathcal{B}(B^{+}\to K^{+}\nu \bar{\nu })$ exceeds $1.2\cdot 10^{-5}(1.3\cdot 10^{-5})$ at $1\sigma$ ($2\sigma$), which tightens with a decreasing upper limit on $\mathcal{B}(B\to K^{\ast }\nu \bar{\nu })$, that is in reach of the Belle II experiment. In view of the strong constraints on electron-muon universality violation in $|\Delta b|=|\Delta s|=1$ processes, viable explanations are heavy, $(5-10)$-TeV tree-level new physics mediators that couple only to tau-flavors, or lepton flavor violating ones. In addition, couplings of similar size to both left- and right-handed quarks are generically required, implying non-minimal BSM sectors which are carefully balanced against flavor constraints. The decay $B_s^0\to \text{invisibles}$ can shed light on whether new physics is light or heavy. In the former case, branching ratios can be as large as $10^{-5}$.

   hep-phPRD(2024)·92 citations
3. 03*

   Anomalous interactions between mesons with nonzero spin and glueballs

   Francesco Giacosa🇵🇱 · Shahriyar Jafarzade🇵🇱 · Robert Pisarski🇺🇸

   Topologically nontrivial fluctuations control the anomalous interactions for the $\eta$ and and $\eta \prime$ pseudoscalar mesons. We consider the anomalous interactions for mesons with higher spin, the heterochiral nonets with $J^{PC}=1^{+-}$ and $2^{-+}$. Under the approximation of a dilute gas of instantons, the mixing angle between non-strange and strange mesons decreases strongly as $J$ increases, and oscillates in sign. Anomalous interactions also open up new, rare decay channels. For glueballs, anomalous interactions indicate that the $X(2600)$ state is primarily gluonic.

   hep-phhep-lathep-thPRD(2024)·18 citations
4. 04*

   Testing the non-unitarity of the leptonic mixing matrix at FASER{\nu} and FASER{\nu}2

   Jesús Miguel Celestino-Ramírez🇲🇽 · F.J. Escrihuela🇪🇸 · L.J. Flores🇲🇽 · O.G. Miranda🇲🇽

   The FASER{\nu} experiment has detected the first neutrino events coming from LHC. Near future high-statistic neutrino samples will allow us to search for new physics within the neutrino sector. Motivated by the forthcoming promising FASER{\nu} neutrino data, and its succesor, FASER{\nu}2, we study its potential for testing the unitarity of the neutrino lepton mixing matrix. Although it would be challenging for FASER{\nu} and FASER{\nu}2 to have strong constraints on this kind of new physics, we discuss its role in contributing to a future improved global analysis.

   hep-phPRD(2024)·11 citations
5. 05*

   Sound in a Bubbly Hybrid Neutron Star

   B.O. Kerbikov🇷🇺 · M.S. Lukashov🇷🇺

   Increasingly precise astrophysical observations of the last decade in combination with intense theoretical studies allow for drawing a conclusion about potential Quark Matter presence in Neutron Stars interiors. Quark Matter may form the Neutron Star inner core or be immersed in the form of bubbles, or droplets. We consider the second scenario and demonstrate that even a small fraction of quark matter bubbles can lead to a high nonlinearity of the sound wave. Below the bubble resonant frequency the sound speed is lower than the ambient value. At the resonance it sharply grows. The peak is constrained by viscous dissipation. Above the resonance the speed exceeds the pure neutron star matter value. The dispersion equation for the bubbly neutron star compressibility is derived.

   hep-phastro-ph.HEPRD(2024)·0 citations
6. 06*

   A constraint to the uncertainty associated with the elements in the quark mixing matrix

   Jae Jun Kim🇺🇸

   We present an extra condition by which the size of the uncertainty associated with the diagonal elements in the quark mixing matrix can be further constrained when the matrix is parameterized by a combination of three mixing angles and a Dirac phase. Then we discuss how the correlations among the uncertainties of the diagonal emenets can be used when we address issues such as the tension in the first row and the column of the matrix and discuss its implications.

   hep-ph0 citations
7. 07*

   Fantômas For QCD: parton distributions in a pion with Bézier parametrizations

   Aurore Courtoy🇲🇽 · Lucas Kotz🇺🇸 · Pavel Nadolsky🇺🇸 · Fred Olness🇺🇸 · Maximiliano Ponce-Chavez🇲🇽 · Varada Purohit🇺🇸

   We report on a new framework to parametrize parton distribution functions (PDFs) and other hadronic nonperturbative functions using polynomial functions realized by Bézier curves. Bézier parameterizations produce a stable fit with a low number of free parameters, while competing in performance with neural networks and offering explicit interpretation. We specifically apply this approach to determine PDFs in a pion, essential for understanding of nonperturbative QCD dynamics.

   hep-ph3 citations
8. 08*

   Amplifying Non-Resonant Production of Dark Sector Particles in Scattering Dominance Regime

   Mingxuan Du🇨🇳 · Jia Liu🇨🇳 · Xiao-Ping Wang🇨🇳 · Tianhao Wu🇨🇳

   We investigate the enhancement of dark sector particle production within the scattering dominant regime. These particles typically exhibit a slight mixing with Standard Model particles through various portals, allowing for their generation through in-medium oscillation from Standard Model particle sources. Our analysis reveals that in the scattering dominance regime, with a significantly smaller scattering mean free path ${\lambda }_{\mathrm{sca}}$ compared to the absorption mean free path ${\lambda }_{\mathrm{abs}}$, the nonresonant production of sterile states can experience an enhancement by a factor of ${\lambda }_{\mathrm{abs}}/{\lambda }_{\mathrm{sca}}$. This phenomenon is demonstrated within the context of kinetic mixing dark photon production at a reactor, precisely satisfying this condition. By incorporating this collisional enhancement, we find that the current sensitivity to the mixing parameter $ϵ$ for dark photons in the TEXONO experiment can be significantly improved across a range spanning from tens of eV to MeV. This advancement establishes the most stringent laboratory constraint within this mass spectrum for the dark photon. Sterile neutrino production, however, does not exhibit such enhancement, either due to the failure to meet the scattering dominance criterion or the neutrino damping in resonant production.

   hep-phPRD(2024)·3 citations
9. 09*

   Laplace Sum Rules in Quantum ChromoDynamics

   Stephan Narison🇫🇷

   We shortly review some applications of the (inverse) Laplace (LSR) transform sum rules in Quantum ChromoDynamics (QCD) for extracting the fundamental QCD parameters (coupling constant ${\alpha }_s$, quark and gluon condensates) and the hadron properties (masses and decay constants). Links of LSR to some other forms of QCD spectral sum rules are also discussed. As prototype examples, we discuss in detail the $\rho$ and $\pi$ meson sum rules.

   hep-ph11 citations
10. 10*

    Probing Inelastic Dark Matter at the LHC, FASER and STCF

    Chih-Ting Lu🇨🇳 · Jianfeng Tu🇨🇳 · Lei Wu🇨🇳

    In this work, we explore the potential of probing the inelastic dark matter (DM) model with an extra U(1)D gauge symmetry at the Large Hadron Collider, ForwArd Search ExpeRiment and Super Tau Charm Factory. To saturate the observed DM relic density, the mass splitting between two light dark states has to be small enough, and thus leads to some distinctive signatures at these colliders. By searching for the long-lived particle, the displaced muon-jets, the soft leptons, and the mono-photon events, we find that the inelastic DM mass in the range of 1 MeV to 210 GeV could be tested.

    hep-phPRD(2024)·13 citations
11. 11*

    Interplay between improved interaction rates and modified cosmological histories for dark matter

    Simone Biondini🇨🇭

    A novel particle has been and still is an intriguing option to explain the strong evidence for dark matter in our universe. To quantitatively predict the dark matter energy density, two main ingredients are needed: interaction rates and an expansion history of the universe. In this work, we explore the interplay between recent progress in the determination of particle production rates and modified cosmological histories. For the freeze-out mechanism, we focus on Sommerfeld and bound-state effects, which boost and make dark matter pair annihilation more efficient. As regards the freeze-in option, we include thermal masses, which enter the decay processes that produce dark matter, and we find that they can suppress or enhance the dark matter yield. We consider a class of modified cosmological histories that induce a faster universe expansion, and we assess their effect in combination with improved particle interaction rates on the dark matter energy density.

    hep-phFront.in Phys.(2023)·5 citations
12. 12*

    Charming-loop contribution to $B_s\to \gamma \gamma$ decay

    Ilia Belov🇮🇹 · Alexander Berezhnoy🇷🇺 · Dmitri Melikhov🇷🇺

    We present a detailed theoretical study of nonfactorizable contributions of the charm-quark loop to the amplitude of the $B_s\to \gamma \gamma$ decay. This contribution involves the $B$-meson three-particle Bethe-Salpeter amplitude, $⟨0|\bar{s}(y)G_{\mu \nu }(x)b(0)|{\bar{B}}_s(p)⟩$, for which we take into account constraints from analyticity and continuity. The charming-loop contribution of interest may be described as a correction to the Wilson coefficient $C_{7\gamma }$, $C_{7\gamma }\to C_{7\gamma }(1+\delta C_{7\gamma })$. We calculate an explicit dependence of $\delta C_{7\gamma }$ on the parameter ${\lambda }_{B_s}$. Taking into account all theoretical uncertainties, $\delta C_{7\gamma }$ may be predicted with better than 10\% accuracy for any given value of ${\lambda }_{B_s}$. For our benchmark point ${\lambda }_{B_s}=0.45$ GeV, we obtain $\delta C_{7\gamma }=0.045\pm 0.004$. Presently, ${\lambda }_{B_s}$ is not known with high accuracy, but its value is expected to lie in the range $0.3\le {\lambda }_{B_s}(\mathrm{GeV})\le 0.6$. The corresponding range of $\delta C_{7\gamma }$ is found to be $0.02\le \delta C_{7\gamma }\le 0.1$. One therefore expects the correction given by charming loops at the level of at least a few percent.

    hep-phPRD(2023)·6 citations
13. 13*

    Monochromatic neutrinos from dark matter through the Higgs portal

    Pablo de la Torre🇪🇸 · Miguel Gutiérrez🇪🇸 · Manuel Masip🇪🇸

    We define a minimal model of dark matter with a fermion singlet $\chi$ coupled to the visible sector through the Higgs portal and with a heavy Dirac neutrino $N$ that opens the annihilation channel $\chi \chi \to N\nu$. The model provides the observed relic abundance consistently with bounds from direct searches and implies a monochromatic neutrino signal at 10 GeV-1 TeV in indirect searches. In particular, we obtain the capture rate of $\chi$ by the Sun and show that the signal could be above the "neutrino floor" produced by cosmic rays showering in the solar surface. In most benchmark models this solar astrophysical background is above the expected dark matter signal, so the model that we propose is a canonical example of WIMP not excluded by direct searches that could be studied at neutrino telescopes and also at colliders.

    hep-phastro-ph.HEJCAP(2023)·3 citations
14. 14*

    Simultaneous detection of boosted dark matter and neutrinos from the semi-annihilation at DUNE

    Mayumi Aoki🇯🇵 · Takashi Toma🇯🇵

    Dark matter direct detection experiments impose the strong bounds on thermal dark matter scenarios. The bound can naturally be evaded if the cross section is momentum transfer or velocity dependent. One can test such thermal dark matter scenarios if dark matter particles are boosted by some mechanism. In this work, we consider a specific semi-annihilation $\chi \chi \to \nu \overline{\chi }$ where $\chi$ ($\overline{\chi }$) is dark matter (anti-dark matter), and search for simultaneous detection of the neutrino and the boosted dark matter in the final state at DUNE. We find that the energies of the neutrino and boosted dark matter are reconstructed by kinematics. In addition, we find that both signals can be testable at DUNE if the dark matter mass is below $8\mathrm{GeV}$, and the scattering cross section is momentum transfer dependent. Even for larger dark matter masses, the two signals can be tested by combination of DUNE and the other experiments such as IceCube/DeepCore and Hyper-Kamiokande.

    hep-phastro-ph.HEJCAP(2024)·14 citations
15. 15*

    Correlation function for the $T_{bb}$ state: Determination of the binding, scattering lengths, effective ranges and molecular probabilities

    A. Feijoo🇪🇸 · L. R. Dai🇨🇳 · L. M. Abreu🇧🇷 · E. Oset🇪🇸

    We perform a study of the $B^{\ast +}{B}^0,B^{\ast 0}{B}^{+}$ correlation functions using an extension of the local hidden gauge approach which provides the interaction from the exchange of light vector mesons and gives rise to a bound state of these components in $I=0$ with a binding energy of about $21$~MeV. After that, we face the inverse problem of determining the low energy observables, scattering length and effective range for each channel, the possible existence of a bound state, and, if found, the couplings of such a state to each $B^{\ast +}{B}^0,B^{\ast 0}{B}^{+}$ component as well as the molecular probabilities of each of the channels. We use the bootstrap method to determine these magnitudes and find that, with errors in the correlation function typical of present experiments, we can determine all these magnitudes with acceptable precision. In addition, the size of the source function of the experiment from where the correlation functions are measured can be also determined with a high precision.

    hep-phnucl-thPRD(2024)·30 citations
16. 16*

    Improving NLO QCD event generators with high-energy EW corrections

    Davide Pagani🇮🇹 · Timea Vitos🇸🇪 · Marco Zaro🇮🇹

    In this work we present a new approach for the combination of electroweak (EW) corrections at high energies, the so-called EW Sudakov logarithms (EWSL), and next-to-leading-order QCD predictions matched to parton-shower simulations (NLO+PS). Our approach is based on a reweighting procedure of NLO+PS events. In particular, both events with and without an extra hard emission from matrix elements are consistently reweighted via the inclusion of the corresponding EWSL contribution. We describe the technical details and the implementation in the MadGraph5_aMC@NLO framework. Via a completely automated procedure, events at this new level of accuracy can be obtained for a vast class of hadroproduction processes. As a byproduct we provide results for phenomenologically relevant physical distributions from top-quark pair and Higgs boson associated production ($t\overline{t}H$) and from the associated production of three $Z$ gauge bosons ($ZZZ$).

    hep-phhep-exEPJC(2024)·18 citations
17. 17*

    Feebly-interacting dark matter

    G. Bélanger🇫🇷 · S. Chakraborti🇬🇧 · A. Pukhov🇷🇺

    We briefly review scenarios with feebly interacting particles (FIMPs) as dark matter candidates. The discussion covers issues with dark matter production in the early universe as well as signatures of FIMPs at the high energy and high intensity frontier as well as in astroparticle and cosmology.

    hep-phEur.Phys.J.ST(2024)·2 citations
18. 18*

    Top Quark Mass Calibration for Monte Carlo Event Generators -- An Update

    Bahman Dehnadi🇩🇪 · André H. Hoang🇦🇹 · Oliver L. Jin🇦🇹 · Vicent Mateu🇪🇸

    We generalize and update our former top quark mass calibration framework for Monte Carlo (MC) event generators based on the $e^{+}{e}^{-}$ hadron-level 2-jettiness ${\tau }_2$ distribution in the resonance region for boosted $t\bar{t}$ production, that was used to relate the PYTHIA 8.205 top mass parameter $m_t^{\mathrm{MC}}$ to the MSR mass $m_t^{\mathrm{MSR}}(R)$ and the pole mass $m_t^{\mathrm{pole}}$. The current most precise direct top mass measurements specifically determine $m_t^{\mathrm{MC}}$. The updated framework includes the addition of the shape variables sum of jet masses ${\tau }_s$ and modified jet mass ${\tau }_m$, and the treatment of two more gap subtraction schemes to remove the $\mathcal{O}({\Lambda }_{\mathrm{QCD}})$ renormalon related to large-angle soft radiation. These generalizations entail implementing a more versatile shape-function fit procedure and accounting for a certain type of $(m_t/Q{)}^2$ power corrections to achieve gap-scheme and observable independent results. The theoretical description employs boosted heavy-quark effective theory (bHQET) at next-to-next-to-logarithmic order (N${}^2$LL), matched to soft-collinear effective theory (SCET) at N${}^2$LL and full QCD at next-to-leading order (NLO), and includes the dominant top width effects. Furthermore, the software framework has been modernized to use standard file and event record formats. We update the top mass calibration results by applying the new framework to PYTHIA 8.205, HERWIG 7.2 and SHERPA 2.2.11. Even though the hadron-level resonance positions produced by the three generators differ significantly for the same top mass parameter $m_t^{\mathrm{MC}}$ value, the calibration shows that these differences arise from the hadronization modeling. Indeed, we find that $m_t^{\mathrm{MC}}$ agrees with $m_t^{\mathrm{MSR}}(1\text{mbox}GeV)$ within $200$ MeV for the three generators and differs from the pole mass by $350$ to $600$ MeV.

    hep-phhep-exJHEP(2023)·27 citations
19. 19*

    'Fat-brane' Universal Extra Dimension model confronted with the ATLAS multi-jet and photonic searches at 13 TeV LHC

    Esra Akyumuk🇹🇷 · Durmus Karabacak🇹🇷

    The current status of `fat-brane' minimal Universal Extra Dimensions (fat-mUED) is studied in the light of ATLAS experiment's recent reports. At the Large Hadron Collider (LHC) color charged first level Kaluza-Klein (KK) particles (first level excited quarks and gluons) can be abundantly pair-produced due to conserved quantity, viz., KK-parity, and strong interaction. The cascade decay of these particles to one or more Standard Model (SM) particle(s) and lighter first level KK particle(s) stops after producing the lightest excited massive state, named as the lightest KK particle (LKP). With the presence of gravity induced decays, stability of the LKP is lost and it may decay to photon or Z-boson by radiating KK-excited gravitons, hence leading to final state with photon(s) at the LHC. A variant signal topology is established when pair-produced first level colored KK particles undergo direct decay to an associated SM partner along with KK-excitations of graviton; thus leading to a signal with two hard jets and substantial missing energy. The ATLAS experiment lately reported two searches at 13 TeV LHC with 139 inverse-femtobarn of data; (i) multi-jet and (ii) photon and jets with missing energy. In both searches, the results showed no substantial deviation from the number of background events of the SM. Provided the absence of any number of excess events in both searches we constrained the parameters of the fat-mUED model, viz., the higher-dimensional Planck mass and the compactification scale.

    hep-phEPJC(2025)·1 citation
20. 20*

    ALP-Assisted Strong First-Order Electroweak Phase Transition and Baryogenesis

    Keisuke Harigaya🇺🇸 · Isaac R. Wang🇺🇸

    Axion-like particles (ALPs) can be naturally lighter than the electroweak scale. We consider an ALP that couples to the Standard Model Higgs to achieve the strong first-order electroweak phase transition. We discuss the two-field dynamics of the phase transition and the associated computation in detail and identify the viable parameter space. The ALP mass can be from the MeV to GeV scale. Baryon asymmetry can be explained by local baryogenesis without violating the current electron and atom electric dipole moment bound in most of the viable parameter space. The viable parameter space can be probed through Higgs exotic decay, rare kaon decay, the electron and atomic electric dipole moment, and the effective number of neutrinos in the cosmic microwave background in the future. The gravitational-wave signal is too weak to be detected.

    hep-phastro-ph.COJHEP(2024)·13 citations
21. 21*

    Dark Matter Capture in Celestial Objects: Treatment Across Kinematic and Interaction Regimes

    Rebecca K. Leane🇺🇸 · Juri Smirnov🇬🇧

    Signatures of dark matter in celestial objects have become of increasing interest due to their powerful detection prospects. To test any of these signatures, the fundamental quantity needed is the rate in which dark matter is captured by celestial objects. Depending on whether dark matter is light, heavy, or comparable in mass to the celestial-body scattering targets, there are different considerations when calculating the capture rate. Furthermore, if dark matter has strong or weak interactions, the physical behaviour important for capture varies. Using both analytic approximations and simulations, we demonstrate how to treat dark matter capture in a range of celestial objects for arbitrary dark matter mass and interaction strength. We release our calculation framework as a public package available in both Python and Mathematica versions, called Asteria.

    hep-phastro-ph.COastro-ph.EPastro-ph.HE+1JCAP(2023)·37 citations
22. 22*

    Sphaleron freeze-in baryogenesis with gravitational waves from the QCD transition

    Fei Gao🇨🇳 · Julia Harz🇩🇪 · Chandan Hati🇪🇸 · Yi Lu🇨🇳 · Isabel M. Oldengott🇧🇪 · Graham White🇬🇧

    A large primordial lepton asymmetry is capable of explaining the baryon asymmetry of the Universe (BAU) through suppression of the electroweak sphaleron rates (``sphaleron freeze-in") which can lead to a first-order cosmic QCD transition with an observable gravitational wave (GW) signal. With next-to-leading order dimensional reduction and the exact 1-loop fluctuation determinant, we accurately compute the lepton asymmetry needed to realize this paradigm, finding it to be an order of magnitude smaller than previous estimates. Further, we apply an improved QCD equation of state capable of describing the phase transition line together with the critical endpoint leading to better agreement with lattice and functional QCD results. Based on this, we identify the range of lepton flavor asymmetries inducing a first-order cosmic QCD transition. We then extract the parameters relevant to the prediction of GW signal from a first-order cosmic QCD transition. Our result showcases the possibility of probing the sphaleron freeze-in paradigm as an explanation of BAU by future gravitational wave experiments like $\mu$Ares.

    hep-phastro-ph.COastro-ph.HEhep-thPLB(2025)·20 citations
23. 23*

    Searching for a Leptophilic Z' and a 3-3-1 symmetry at CLIC

    A.Alves🇧🇷 · G. Gil da Silveira🇧🇷 · V. P. Gonçalves🇧🇷 · F. S. Queiroz🇧🇷 · Y. M. Oviedo-Torres🇧🇷 · J. Zamora-Saa🇨🇱

    We derive the discovery potential of a leptophilic Z', and a Z' rising from a $SU(3)\times SU(3{)}_L\times U(1{)}_N$ symmetry at the Compact Linear Collider (CLIC), which is planned to host $e^{+}{e}^{-}$ collisions with 3 TeV center-of-mass energy. We perform an optimized selection cut strategy on the transverse momentum, pseudorapidity, and invariant mass of the dileptons in order to enhance the collider sensitivity. We find that CLIC can potentially reach a $5\sigma$ signal of a $1-3$~TeV leptophilic Z' with less than $1f{b}^{-1}$ of integrated luminosity. As for the Z' belonging to a 3-3-1 symmetry, CLIC will offer a complementary probe with the potential to impose $M_{Z^{\prime }}>3$~TeV with $\mathcal{L}=2f{b}^{-1}$.

    hep-phhep-exEPJC(2024)·4 citations
24. 24*

    Semi-inclusive direct photon+jet and ${\pi }^0$+jet correlations measured in $p+p$ and central Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=200$ GeV

    The STAR Collaboration

    The STAR experiment at RHIC reports new measurements of jet quenching based on the semi-inclusive distribution of charged-particle jets recoiling from direct photon (${\gamma }_{\mathrm{dir}}$) and neutral pion (${\pi }^0$) triggers in pp and central Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=200$ GeV, for triggers in the range $9<E_{\mathrm{T}}^{\mathrm{trig}}<20$ GeV. The datasets have integrated luminosities of 3.9${\mathrm{nb}}^{-1}$ for Au+Au and 23${\mathrm{pb}}^{-1}$ for pp collisions. Jets are reconstructed using the anti-$k_{\mathrm{T}}$ algorithm with resolution parameters $R$=0.2 and 0.5. The large uncorrelated jet background in central Au+Au collisions is corrected using a mixed-event approach, which enables precise charged-particle jet measurements at low transverse momentum $p_{\mathrm{T},\mathrm{jet}}^{\mathrm{ch}}$ and large $R$. Recoil-jet distributions are reported in the range $p_{\mathrm{T},\mathrm{jet}}^{\mathrm{ch}}<25$ \gev. Comparison of the distributions measured in pp and Au+Au collisions reveals strong medium-induced jet yield suppression for $R=0.2$, with markedly less suppression for $R=0.5$. Comparison is also made to theoretical models incorporating jet quenching. These data provide new insight into the mechanisms underlying jet quenching and the angular dependence of medium-induced jet-energy transport, and provide new constraints on modelling such effects.

    ↳ nucl-exhep-exhep-phnucl-thPRC(2025)·21 citations
25. 25*

    Measurement of in-medium jet modification using direct photon+jet and ${\pi }^0$+jet correlations in $p+p$ and central Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=200$ GeV

    STAR Collaboration

    The STAR Collaboration presents measurements of the semi-inclusive distribution of charged-particle jets recoiling from energetic direct-photon (${\gamma }_{\mathrm{dir}}$) and neutral-pion (${\pi }^0$) triggers in p+p and central Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ GeV over a broad kinematic range, for jet resolution parameters $R$=0.2 and 0.5. Medium-induced jet yield suppression is observed to be larger for $R$=0.2 than for 0.5, reflecting the angular range of jet energy redistribution due to quenching. The predictions of model calculations incorporating jet quenching are not fully consistent with the observations. These results provide new insight into the physical origins of jet quenching.

    ↳ nucl-exhep-exhep-phnucl-thPRL(2025)·21 citations
26. 26*

    Measuring black hole spin through gravitational lensing of pulsars

    Amjad Ashoorioon🇮🇷 · Mohammad Bagher Jahani Poshteh🇮🇷 · Robert B. Mann🇨🇦

    We propose a new procedure for measuring the spin of a black hole with an unprecedented accuracy based on the gravitational lensing of millisecond pulsars. We derive the basic equations for lensing by a rotating black hole. We show that the frame dragging effect increases the deflection angle of a light ray co-rotating with the black hole. For the primary (secondary) images the angular positions are larger (smaller) for a rotating black hole by an amount on the order of tens of microarcseconds. The differential time delay of images for the case in which the lens is a rotating black hole is smaller than that in the case of non-rotating lens of the same mass, and it can be larger than a few milliseconds. We show that this quantity offers the possibility of reducing the error of spin measurement to less than one percent if we could measure the differential time delay with accuracy of microseconds. We also study relativistic images that are produced by light rays that rotate around the black hole before reaching the observer. The angular positions of relativistic images on the same side as the primary (secondary) image are a few microarcseconds larger (smaller) if the black hole is rotating. Furthermore, the differential time delay between relativistic images is about twelve orders of magnitude larger in the case of rotating lens.

    ↳ gr-qcastro-ph.COhep-phhep-thClass.Quant.Grav.(2025)·1 citation
27. 27*

    Induced Gravitational Waves with Kination Era for Recent Pulsar Timing Array Signals

    Keisuke Harigaya🇺🇸 · Keisuke Inomata🇺🇸 · Takahiro Terada🇰🇷

    The evidence of the stochastic gravitational-wave background around the nano-hertz frequency range was recently found by worldwide pulsar timing array (PTA) collaborations. One of the cosmological explanations is the gravitational waves induced by enhanced curvature perturbations, but the issue of primordial black hole (PBH) overproduction in this scenario was pointed out in the literature. Motivated by this issue and the ${\Omega }_{\text{GW}}\sim f^2$ scaling suggested by the data, we study the gravitational waves induced in a cosmological epoch dominated by a stiff fluid ($w=1$) and find that they can safely explain the PTA data well without PBH overproduction.

    ↳ astro-ph.COgr-qchep-phPRD(2023)·65 citations
28. 28*

    The future search for low-frequency axions and new physics with the FLASH resonant cavity experiment at Frascati National Laboratories

    David Alesini🇮🇹 · Danilo Babusci🇮🇹 · Paolo Beltrame🇬🇧 · Fabio Bossi🇮🇹 · Paolo Ciambrone🇮🇹 · Alessandro D'Elia🇮🇹 · Daniele Di Gioacchino🇮🇹 · Giampiero Di Pirro🇮🇹 · Babette Döbrich🇩🇪 · Paolo Falferi🇮🇹 · Claudio Gatti🇮🇹 · Maurizio Giannotti🇺🇸 and 16 other authors

    We present a proposal for a new experiment, the FINUDA magnet for Light Axion SearcH (FLASH), a large resonant-cavity haloscope in a high static magnetic field which is planned to probe new physics in the form of dark matter (DM) axions, scalar fields, chameleons, hidden photons, as well as high frequency gravitational waves (GWs). Concerning the QCD axion, FLASH will search for these particles as the DM in the mass range (0.49-1.49) ueV, thus filling the mass gap between the ranges covered by other planned searches. A dedicated Microstrip SQUID operating at ultra-cryogenic temperatures will amplify the signal. The frequency range accessible overlaps with the Very High Frequency (VHF) range of the radio wave spectrum and allows for a search in GWs in the frequency range (100-300) MHz. The experiment will make use of the cryogenic plant and magnet of the FINUDA experiment at INFN Frascati National Laboratories near Rome (Italy); the operations needed to restore the functionalities of the apparatus are currently underway. We present the setup of the experiment and the sensitivity forecasts for the detection of axions, scalar fields, chameleons, hidden photons, and GWs.

    ↳ physics.ins-dethep-exhep-phPhys.Dark Univ.(2023)·70 citations
29. 29*

    ${}^{16}$O spectral function from coupled-cluster theory: applications to lepton-nucleus scattering

    Joanna E. Sobczyk🇩🇪 · Sonia Bacca🇩🇪

    We calculate the ${}^{16}$O spectral function by combining coupled-cluster theory with a Gaussian integral transform and by expanding the integral kernel in terms of Chebyshev polynomials to allow for a quantification of the theoretical uncertainties. We perform an analysis of the spectral function and employ it to predict lepton-nucleus scattering. Our results well describe the ${}^{16}$O electron scattering data in the quasi-elastic peak for momentum transfers $|\mathbf{q}|⪆500$ MeV and electron energies up to 1.2 GeV, extending therefore the so-called first principles approach to lepton-nucleus cross sections well into the relativistic regime. To prove the applicability of this method to neutrino-nucleus cross sections, we implement our ${}^{16}$O spectral functions in the NuWro Monte Carlo event generator and provide a comparison with recently published T2K neutrino data.

    ↳ nucl-thhep-phPRC(2024)·16 citations
30. 30*

    Multiple Mellin-Barnes integrals and triangulations of point configurations

    Sumit Banik🇨🇭 · Samuel Friot🇫🇷

    We present a novel technique for the analytic evaluation of multifold Mellin-Barnes (MB) integrals, which commonly appear in physics, as for instance in the calculations of multi-loop multi-scale Feynman integrals. Our approach is based on triangulating a set of points which can be assigned to a given MB integral, and yields the final analytic results in terms of linear combinations of multiple series, each triangulation allowing the derivation of one of these combinations. When this technique is applied to the computation of Feynman integrals, the involved series are of the (multivariable) hypergeometric type. We implement our method in the Mathematica package MBConicHulls.wl, an already existing software dedicated to the analytic evaluation of multiple MB integrals, based on a recently developed computational approach using intersections of conic hulls. The triangulation method is remarkably faster than the conic hulls approach and can thus be used for the calculation of higher-fold MB integrals as we show here by computing triangulations for highly complicated objects such as the off-shell massless scalar one-loop 15-point Feynman integral whose MB representation has 104 folds. As other applications we show how this technique can provide new results for the off-shell massless conformal hexagon and double box Feynman integrals, as well as for the hard diagram of the two loop hexagon Wilson loop.

    ↳ hep-thhep-phmath-phmath.MPPRD(2024)·16 citations
31. 31*

    Schwinger-Keldysh effective field theory for stable and causal relativistic hydrodynamics

    Akash Jain🇳🇱 · Pavel Kovtun🇨🇦

    We construct stable and causal effective field theories (EFTs) for describing statistical fluctuations in relativistic diffusion and relativistic hydrodynamics. These EFTs are fully non-linear, including couplings to background sources, and enable us to compute n-point time-ordered correlation functions including the effects of statistical fluctuations. The EFTs we construct are inspired by the Maxwell-Cattaneo model of relativistic diffusion and Müller-Israel-Stewart model of relativistic hydrodynamics respectively, and have been derived using both the Martin-Siggia-Rose and Schwinger-Keldysh formalisms. The EFTs non-linearly realise the dynamical Kubo-Martin-Schwinger (KMS) symmetry, which ensures that n-point correlation functions and interactions in the theory satisfy the appropriate fluctuation-dissipation theorems. Since these EFTs typically admit ultraviolet sectors that are not fixed by the low-energy infrared symmetries, we find that they simultaneously admit multiple realisations of the dynamical KMS symmetry. We also comment on certain obstructions to including statistical fluctuations in the recently-proposed stable and causal Bemfica-Disconzi-Noronha-Kovtun model of relativistic hydrodynamics.

    ↳ hep-thcond-mat.stat-mechhep-phnucl-th+1JHEP(2024)·39 citations
32. 32*

    Relativistic hydrodynamic fluctuations from an effective action: causality, stability, and the information current

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

    Causality is necessary for retarded Green's functions to remain retarded in all inertial frames in relativity, which ensures that dissipation of fluctuations is a Lorentz invariant concept. For first-order BDNK theories with stochastic fluctuations, introduced via the Schwinger-Keldysh formalism, we show that imposing causality and stability leads to correlation functions of hydrodynamic fluctuations that only display the expected physical properties at small frequencies and wavenumber, i.e., within the expected regime of validity of the first-order approach. For second-order theories of Israel and Stewart type, constructed using the information current such that entropy production is always non-negative, a stochastic formulation is presented using the Martin-Siggia-Rose approach where imposing causality and stability leads to correlators with the desired properties. We also show how Green's functions can be determined from such an action. We identify a ${\mathbb{Z}}_2$ symmetry, analogous to the Kubo-Martin-Schwinger symmetry, under which this Martin-Siggia-Rose action is invariant. This modified Kubo-Martin-Schwinger symmetry provides a new guide for the effective action formulation of hydrodynamic systems with dynamics not solely governed by conservation laws. Furthermore, this symmetry ensures that the principle of detailed balance is valid in a covariant manner. We employ the new symmetry to further clarify the connection between the Schwinger-Keldysh and Martin-Siggia-Rose approaches, establishing a precise link between these descriptions in second-order theories of relativistic hydrodynamics. Finally, the modified Kubo-Martin-Schwinger symmetry is used to determine the corresponding action describing diffusion in Israel-Stewart theories in a general hydrodynamic frame.

    ↳ hep-thhep-phnucl-thPRD(2023)·31 citations
33. 33*

    Dilepton polarization as a signature of plasma anisotropy

    Maurice Coquet🇫🇷 · Xiaojian Du🇪🇸 · Jean-Yves Ollitrault🇫🇷 · Soeren Schlichting🇩🇪 · Michael Winn🇫🇷

    We propose the angular distribution of lepton pairs produced in ultrarelativistic heavy-ion collisions as a probe of thermalization of the quark-gluon plasma. We focus on dileptons with invariant masses large enough that they are produced through quark-antiquark annihilation in the early stages of the collision. The angular distribution of the lepton in the rest frame of the pair then reflects the angular distribution of quark momenta. At early times, the transverse pressure of the quark-gluon plasma is larger than its longitudinal pressure as a result of the fast longitudinal expansion, which results in an oblate lepton distribution. By contrast, direct (Drell-Yan) production by quarks and antiquarks from incoming nuclei, whose momenta are essentially longitudinal, results in a prolate distribution. As the invariant mass increases, Drell-Yan gradually becomes the dominant source of dilepton production, and the lepton distribution evolves from oblate to prolate. The invariant mass at which the transition occurs is highly sensitive to the equilibration time of the quark-gluon plasma or, equivalently, the shear viscosity over entropy ratio $\eta /s$ in the early stages of the collision.

    ↳ nucl-thhep-exhep-phnucl-exPRL(2024)·27 citations
34. 34*

    Bayesian location of the QCD critical point from a holographic perspective

    Mauricio Hippert🇺🇸 · Joaquin Grefa🇺🇸 · T. Andrew Manning🇺🇸 · Jorge Noronha🇺🇸 · Jacquelyn Noronha-Hostler🇺🇸 · Israel Portillo Vazquez🇺🇸 · Claudia Ratti🇺🇸 · Romulo Rougemont🇧🇷 · Michael Trujillo🇺🇸

    A fundamental question in QCD is the existence of a phase transition at large doping of quarks over antiquarks. We present the first prediction of a QCD critical point (CP) from a Bayesian analysis constrained by first principle results at zero doping. We employ the gauge/gravity duality to map QCD onto a theory of dual black holes. Predictions for the CP location in different realizations of the model overlap at one sigma. Even if many prior samples do not include a CP, one is found in nearly 100\% of posterior samples, indicating a strong preference for a CP.

    ↳ nucl-thhep-phhep-thnucl-exPRD(2024)·121 citations
35. 35*

    Black Hole from Entropy Maximization

    Yuki Yokokura🇯🇵

    One quantum characterization of a black hole motivated by (local) holography and thermodynamics is that it maximizes thermodynamic entropy for a given surface area. In the context of quantum gravity, this could be more fundamental than the classical characterization by a horizon. As a step, we explore this possibility by solving the 4D semi-classical Einstein equation with many matter fields. For highly-excited spherically-symmetric static configurations, we apply local typicality and estimate the entropy including self-gravity to derive its upper bound. The saturation condition uniquely determines the entropy-maximized configuration: self-gravitating quanta condensate into a radially-uniform dense configuration with no horizon, where the self-gravity and a large quantum pressure induced by the curvatures are balanced and no singularity appears. The interior metric is a self-consistent and non-perturbative solution in Planck's constant. The maximum entropy, given by the volume integral of the entropy density, agrees with the Bekenstein-Hawking formula through self-gravity, deriving the Bousso bound for thermodynamic entropy. Finally, 10 future prospects are discussed, leading to a speculative view that the configuration represents a quantum-gravitational condensate in a semi-classical manner.

    ↳ hep-thgr-qchep-phquant-phPRD(2025)·5 citations
36. 36*

    A New Solution to the Callan Rubakov Effect

    T. Daniel Brennan🇺🇸

    In this paper we study the scattering of massive fermions off of smooth, spherically symmetric monopoles in $4d$ $SU(2)$ gauge theory. We propose a complete physical picture of the monopole-fermion interaction which encompasses all angular momentum modes. We show that as an in-going fermion scatters off a monopole, it excites trapped $W$-bosons in the monopole core by a version of the Witten effect so that the monopole can accrue charge and transform into a dyon at parametrically low energies. The imparted electric charge is then protected from decay by an emergent ${\mathbb{Z}}_N$ generalized global symmetry, creating a stable dyon. At sufficiently low energies, the scattered fermion can be trapped by the dyon's electrostatic potential, forming a bound state, which can decay into spherically symmetric fermion modes subject to the preserved ${\mathbb{Z}}_N$ global symmetry. We propose that monopole-fermion scattering can be described in this way without needing to add ``new'' states to the Hilbert space, thereby eliminating a long standing confusion in the Callan Rubakov effect.

    ↳ hep-thhep-phJHEP(2024)·34 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.