Tue·Aug 15, 2023Tuesday·August 15, 2023

1. 01*

   Matrix element corrections in the Pythia8 parton shower in the context of matched simulations at next-to-leading order

   Stefano Frixione🇮🇹 · Simone Amoroso🇩🇪 · Stephen Mrenna🇺🇸

   We discuss the role of matrix element corrections (MEC) to parton showers in the context of MC@NLO-type matchings for processes that feature unstable resonances, where MEC are liable to result in double-counting issues, and are thus generally not employed. By working with Pythia8, we show that disabling all MEC is actually unnecessary in computations based on the narrow-width approximation, and we propose alternative MEC settings which, while still avoiding double counting, allow one to include hard-recoil effects in the simulations of resonance decays. We illustrate our findings by considering top-antitop production at the LHC, and by comparing MadGraph_aMC@NLO predictions with those of POWHEG-BOX and standalone Pythia8.

   hep-phEPJC(2023)·9 citations
2. 02*

   Testing $Z$ boson rare decays $Z\to H_1\gamma ,A_1\gamma$ with $(g-2{)}_{\mu }$, $M_W$, and $BR(h_{\mathrm{SM}}\to Z\gamma )$ in the NMSSM

   Subhadip Bisal🇮🇳 · Debottam Das🇮🇳

   We study the rare decay process of $Z$ boson into photon, accompanied by a CP-even or CP-odd scalar. We present the analytical delineation of the processes through the model-independent parametrizations of the new physics couplings and, finally, consider the Next-to-Minimal Supersymmetric Standard Model to mark out the parameter space where the branching fraction can have the maximum value. As a part of the necessary phenomenological and experimental cross-checks, we aim to fit the anomalous magnetic moment of the muon and $W$ boson mass anomaly through the supersymmetric contributions. We also find that the decays $Z\to H_1\gamma ,A_1\gamma$ can serve as an excellent complementary test to $BR(h_{\mathrm{SM}}\to Z\gamma )$. In fact, to facilitate future searches, we unveil a few benchmark points that additionally satisfy the deviation of $BR(h_{\mathrm{SM}}\to Z\gamma )$ from the SM value based on the recent measurements of ATLAS and CMS. Future proposals such as ILC, CEPC, and FCC-ee are anticipated to operate for multiple years, focusing on center-of-mass energy near the $Z$ pole. Consequently, these projects will be capable of conducting experiments at the Giga-$Z$ ($10^9$ of $Z$ bosons) and Tera-$Z$ ($10^{12}$ of $Z$ bosons) phases, which may probe the aforesaid rare decay processes, thus the model as well. These unconventional yet complementary searches offer different routes to explore the supersymmetric models with extended Higgs sectors like NMSSM.

   hep-phEPJC(2024)·7 citations
3. 03*

   Analysis of the strong vertices of ${\Sigma }_c\Delta D^{\ast }$ and ${\Sigma }_b\Delta B^{\ast }$ in QCD sum rules

   Jie Lu🇨🇳 · Guo-Liang Yu🇨🇳 · Zhi-Gang Wang🇨🇳 · Bin Wu🇨🇳

   In this work, we analyze the strong vertices ${\Sigma }_c\Delta D^{\ast }$ and ${\Sigma }_b\Delta B^{\ast }$ using the three-point QCD sum rules under the tensor structures $i{ϵ}^{\rho \tau \alpha \beta }{p}_{\alpha }{p}_{\beta }^{\prime }$, $p^{\rho }{p}^{\prime \tau }$ and $p^{\rho }{p}^{\tau }$. We firstly calculate the momentum dependent strong coupling constants $g(Q^2)$ by considering contributions of the perturbative part and the condensate terms $⟨\overline{q}q⟩$, $⟨g_s^{2}GG⟩$, $⟨\overline{q}{g}_s\sigma Gq⟩$ and $⟨\overline{q}q{⟩}^2$. By fitting these coupling constants into analytical functions and extrapolating them into time-like regions, we then obtain the on-shell values of strong coupling constants for these vertices. The results are $g_{1{\Sigma }_c\Delta D^{\ast }}=5.13_{-0.49}^{+0.39}$ GeV${}^{-1}$, $g_{2{\Sigma }_c\Delta D^{\ast }}=-3.03_{-0.35}^{+0.27}$ GeV${}^{-2}$, $g_{3{\Sigma }_c\Delta D^{\ast }}=17.64_{-1.95}^{+1.51}$ GeV${}^{-2}$, $g_{1{\Sigma }_b\Delta B^{\ast }}=20.97_{-2.39}^{+2.15}$ GeV${}^{-1}$, $g_{2{\Sigma }_b\Delta B^{\ast }}=-11.42_{-1.28}^{+1.17}$ GeV${}^{-2}$ and $g_{3{\Sigma }_b\Delta B^{\ast }}=24.87_{-2.82}^{+2.57}$ GeV${}^{-2}$. These strong coupling constants are important parameters which can help us to understand the strong decay behaviors of hadrons.

   hep-phEPJC(2023)·8 citations
4. 04*

   Diquarks and the production of charmed baryons

   Hyeongock Yun🇰🇷 · Sungsik Noh🇰🇷 · Sanghoon Lim🇰🇷 · Taesoo Song🇩🇪 · Juhee Hong🇰🇷 · Aaron Park🇰🇷 · Su Houng Lee🇰🇷 · Benjamin Dönigus🇩🇪

   Utilizing a quark model characterized by parameters that effectively replicate the masses of ground state hadrons, we illustrate that $(us)$ or $(ds)$ diquarks exhibit greater compactness in comparison to $(ud)$ diquarks. Concretely, the binding energy of the $(us)$ diquark - defined as the diquark's mass minus the combined masses of its individual quarks - is found to be stronger than that of the $(ud)$ diquark. This heightened attraction present in $(us)$ diquarks could lead to enhanced production of ${\Xi }_c/D$ particles in high-energy pp or ultrarelativistic heavy-ion collisions.

   hep-phnucl-exnucl-thPLB(2024)·3 citations
5. 05*

   $X(3960)$, $X_0(4140)$, and other compact $cs\bar{c}\bar{s}$ states

   Shi-Yuan Li🇨🇳 · Yan-Rui Liu🇨🇳 · Zi-Long Man🇨🇳 · Zong-Guo Si🇨🇳 · Jing Wu🇨🇳

   We study the spectrum and rearrangement decays of S-wave $cs\bar{c}\bar{s}$ tetraquark states in a simplified quark model. The masses and widths are estimated by assuming that the $X(4140)$ is the lower $1^{++}$ $cs\bar{c}\bar{s}$ tetraquark. Comparing our results with experimental measurements, we find that the recently observed $X(3960)$ by LHCb can be assigned as the lowest $0^{++}$ $cs\bar{c}\bar{s}$ tetraquark state and the $X_0(4140)$ could be the second lowest $0^{++}$ $cs\bar{c}\bar{s}$ tetraquark. Predictions of ratios between partial widths for the involved tetraquarks are given. We call for searches for more $cs\bar{c}\bar{s}$ tetraquarks with $J^{PC}=1^{+-}$, $0^{++}$, and $2^{++}$.

   hep-phhep-exhep-latnucl-ex+1CPC(2024)·10 citations
6. 06*

   Forces inside a strongly-coupled scalar nucleon

   Xianghui Cao🇨🇳 · Yang Li🇨🇳 · James P. Vary🇺🇸

   We investigate the gravitational form factors of a strongly coupled scalar theory that mimic the interaction between the nucleon and the pion. The non-perturbative calculation is based on the light-front Hamiltonian formalism. We renormalize the energy-momentum tensor with a Fock sector dependent scheme. We also systematically analyze the Lorentz structure of the energy-momentum tensor and identify the suitable hadron matrix elements to extract the form factors, avoiding the contamination of spurious contributions. We verify that the extracted form factors obey momentum conservation as well as the mechanical stability condition. From the gravitational form factors, we compute the energy and pressure distributions of the system. Furthermore, we show that utilizing the Hamiltonian eigenvalue equation, the off-diagonal Fock sector contributions from the interaction term can be converted to diagonal Fock sector contributions, yielding a systematic non-perturbative light-front wave function representation of the energies and forces inside the system.

   hep-phhep-thnucl-thPRD(2023)·22 citations
7. 07*

   Contributions of inert electroweak multiplets to Higgs properties

   Hugues Beauchesne🇹🇼 · Cheng-Wei Chiang🇹🇼

   New physics could manifest itself in the form of electroweak multiplets that interact at tree level with the Higgs boson but do not mix with Standard Model fields or acquire expectation values. In this paper, we study the potential contributions of such inert multiplets to several crucial Higgs properties, namely, the branching ratio of the Higgs to a $Z$ boson and a photon (or massless dark photon) and the triple Higgs coupling. Constraints from the Higgs signal strengths, oblique parameters and unitarity are taken into account.

   hep-phJHEP(2023)·2 citations
8. 08*

   Exclusive quarkonium photoproduction in $A$+$A$ UPCs at the LHC in NLO pQCD

   Kari J. Eskola🇫🇮 · Christopher A. Flett🇫🇮 · Vadim Guzey🇫🇮 · Topi Löytäinen🇫🇮 · Hannu Paukkunen🇫🇮

   We present the first study of coherent exclusive quarkonium ($J/\psi$, ${\rm Y}$) photoproduction in ultraperipheral nucleus-nucleus collisions (UPCs) at the LHC in the framework of collinear factorization and next-to-leading order (NLO) perturbative QCD (pQCD). We make NLO predictions for the $J/\psi$ and ${\rm Y}$ rapidity distributions for lead (Pb) and oxygen (O) beams, and quantify their dependence on the factorization/renormalization scale, nuclear parton distribution functions (PDFs) and their uncertainties, and on differences between nuclear PDFs and generalized parton distribution functions (GPDs). We show that within the PDF-originating uncertainties our approach provides a good description of the available $J/\psi$ photoproduction data in Pb+Pb UPCs at the LHC but that the scale uncertainty is significant. We demonstrate that at NLO pQCD the quark contributions are important in the $J/\psi$ case but that gluons clearly dominate the ${\rm Y}$ cross sections. We also study how the scale dependence could be tamed by considering O+O/Pb+Pb ratios of the exclusive $J/\psi$ UPC cross sections, and how HERA and p+p/Pb LHC data can help in obtaining better-controlled NLO predictions in the ${\rm Y}$ case.

   hep-phnucl-thPoS(2024)·1 citation
9. 09*

   Dark Coloured Scalars Impact on Single and Di-Higgs Production at the LHC

   Pedro Gabriel🇵🇹 · Margarete Mühlleitner🇩🇪 · Daniel Neacsu🇵🇹 · Rui Santos🇵🇹

   The search for Dark Matter (DM) at colliders is primarily pursued via the detection of missing energy in particular final states. These searches are based on the production and decay processes where final states include DM particles and at least one Standard Model (SM) particle. DM will then reveal itself as missing energy. An alternative form to get a hint of a dark sector is via loop contribution to SM processes. In this case, it is not even relevant if the new particles have their origin in the dark sector of the model. In this work we discuss the impact of an arbitrary number of coloured scalars in single Higgs and double Higgs production at the Large Hadron Collider (LHC), and we show their complementarity. We determine the range of variation of the corrections relative to the SM for an arbitrary number of coloured scalars $n$, and discuss in more detail the cases $n=1$ and $n=2$.

   hep-phhep-exEPJC(2025)·2 citations
10. 10*

    Constraining inverse moment of $B$-meson distribution amplitude using Lattice QCD data

    Rusa Mandal🇮🇳 · Soumitra Nandi🇮🇳 · Ipsita Ray🇮🇳

    We constrain the inverse moment of the $B$-meson light-cone distribution amplitude (LCDA), ${\lambda }_B$ in heavy quark effective theory, using form factor estimates from Lattice QCD collaboration. The estimation of the parameter ${\lambda }_B$ has, until now, relied solely on QCD sum rule methods and deals with significant uncertainty. In this work, we express the form factors for the $B\to K$ channel, calculated within the light-cone sum rule (LCSR) approach, in terms of the $B$-meson LCDAs. By incorporating recent Lattice results from the HPQCD collaboration for the $B\to K$ form factors at zero momentum transfer ($q^2$ = 0), we impose constraints on this parameter. Consequently, we achieve a twofold reduction in uncertainty compared to the QCD sum rule estimate, yielding ${\lambda }_B=338\pm 68$ MeV, when the $B$-meson LCDAs are expressed in the Exponential model. Additionally, we compare the form factor predictions, using the constrained ${\lambda }_B$ value, with the earlier analyses for other channels as well, such as $B\to \pi$ and $B\to D$.

    hep-phhep-latPLB(2024)·14 citations
11. 11*

    Dibaryons and where to find them

    M. Bashkanov🇬🇧 · D.P. Watts🇬🇧 · G. Clash🇬🇧 · M. Mocanu🇬🇧 · M. Nicol🇬🇧

    In recent years there has been tremendous progress in the investigation of bound systems of quarks with multiplicities beyond the more usual two- and three-quark systems. Experimental and theoretical progress has been made in the four-, five- and even six-quark sectors. In this paper, we review the possible lightest six-quark states using a simple ansatz based on SU(3) symmetry and evaluate the most promising decay branches. The work will be useful to help focus future experimental searches in this six-quark sector.

    hep-phnucl-thJ.Phys.G(2024)·8 citations
12. 12*

    Coherently diffractive dissociation in electron-hadron collisions: from HERA to the future EIC

    Tuomas Lappi🇫🇮 · Anh Dung Le🇫🇮 · Heikki Mäntysaari🇫🇮

    We present numerical results on diffractive dissociation with large invariant mass diffractive final states in the scattering of an electron off a hadron. The diffractive large-mass resummation is performed using the nonlinear Kovchegov-Levin equation, taking into account running coupling corrections. For the scattering off the proton, a (modified) McLerran-Venugopalan amplitude is used as the initial condition for the nonlinear evolution, with free parameters being constrained by the HERA inclusive data. The results show a reasonable description of the HERA diffractive structure function data at moderately large diffractive mass when the impact parameter profile is constrained by the low-mass diffractive cross section data. The calculation is extended to nuclear scattering, where the initial condition is generalized from the proton case employing the optical Glauber model. The nonlinear large-mass resummation predicts a strong nuclear modification in diffractive scattering off a nuclear target in kinematics accessible at the future Electron-Ion collider.

    hep-ph0 citations
13. 13*

    Inflation, superheavy metastable strings and gravitational waves in non-supersymmetric flipped SU(5)

    George Lazarides🇬🇷 · Rinku Maji🇰🇷 · Ahmad Moursy🇪🇬 · Qaisar Shafi🇺🇸

    Motivated by the NANOGrav 15 year data and other recent investigations of stochastic gravitational background radiation based on pulsar timing arrays, we show how superheavy strings survive inflation but the slightly heavier monopoles do not in a non-supersymmetric hybrid inflation model based on flipped $SU(5)$. With the dimensionless string tension parameter $G\mu \sim 10^{-6}$, the gravitational wave spectrum emitted by the strings, which are metastable due to breaking caused by monopole-antimonopole quantum mechanical tunneling, is compatible with the latest NANOGrav measurement as well as the advanced LIGO-VIRGO third run data. The string network undergoes about 30 $e$-foldings of inflation which suppresses the spectrum in the LIGO-VIRGO frequency range. With the symmetry breaking chain $SU(5)\times U(1{)}_X\to SU(3{)}_c\times SU(2{)}_L\times U(1{)}_Z\times U(1{)}_X\to SU(3{)}_c\times SU(2{)}_L\times U(1{)}_Y$, the estimated proton lifetime is of order $10^{36}-10^{37}$ yrs.

    hep-phastro-ph.COJCAP(2024)·47 citations
14. 14*

    Charting the new physics through one-loop effects in the muon magnetic dipole moment

    Shi-Ping He🇰🇷

    Since the announcement of the muon $g-2$ measurements, numerous studies have been devoted to exploring the new physics through this precision probe. In specific models, the new physics contributions depend on the couplings and mass scales. Approximate formulae are widely adopted when determining the new physics contributions. This manuscript is dedicated to comprehensive analytical results and approximations for the canonical interactions at one-loop level, which is universal for the spin-half fermions and can serve as a useful reference for the magnetic dipole moment calculations. We present the analytic and approximate expressions for the scalar and vector mediator cases, supplemented by explicit examples in specific models to illustrate their applications. For given muon interactions, we can estimate both the sign and magnitude of the contributions conveniently. Furthermore, we investigate the broader physical implications of these results, offering insights into potential new physics.

    hep-phhep-exEur.Phys.J.Plus(2026)·3 citations
15. 15*

    Magnetic monopole meets primordial black hole: an extended analysis

    Chen Zhang🇺🇸 · Xin Zhang🇺🇸

    We investigate gravitational capture of magnetic monopoles by primordial black holes (PBH) that evaporate before Big Bang Nucleosynthesis (BBN), a hypothetical process which was once proposed as an alternative solution to the monopole problem. Magnetic monopoles produced in phase transitions of a grand or partially unified gauge theory are considered. We prove analytically that for all extended PBH mass functions that preserve radiation domination, it is impossible to reduce the monopole abundance via gravitational capture by PBHs to values significantly below the one set by monopole annihilation (or below its initial abundance if it is smaller), regardless of the nature of the capture process (diffusive or non-diffusive). Therefore, the monopole problem cannot be solved by PBH capture in a radiation-dominated era in the early universe.

    hep-phastro-ph.COastro-ph.HEgr-qcEPJC(2024)·14 citations
16. 16*

    Heavy quark diffusion coefficient during hydrodynamization -- non-equilibrium vs. equilibrium

    Kirill Boguslavski🇦🇹 · Aleksi Kurkela🇳🇴 · Tuomas Lappi🇫🇮 · Florian Lindenbauer🇦🇹 · Jarkko Peuron🇫🇮

    We compute the heavy quark momentum diffusion coefficient using effective kinetic theory for a system going through bottom-up isotropization until approximate hydrodynamization. We find that when comparing the nonthermal diffusion coefficient to the thermal one for the same energy density, the observed deviations throughout the whole evolution are within 30% from the thermal value. For thermal systems matched to other quantities we observe considerably larger deviations. We also observe that the diffusion coefficient in the transverse direction dominates at large occupation number, whereas for an underoccupied system the longitudinal diffusion coefficient dominates. Similarly, we study the jet quenching parameter, where we obtain a smooth evolution connecting the large values of the glasma phase with the smaller values in the hydrodynamical regime.

    hep-phPoS(2024)·1 citation
17. 17*

    Spectroscopic survey of higher-lying states of $B_c$ meson family

    Xue-Jian Li🇨🇳 · Yu-Shuai Li🇨🇳 · Fu-Lai Wang🇨🇳 · Xiang Liu🇨🇳

    In this work, we investigate the spectroscopy of higher $B_c$ mesons, with a special focus on the consideration of the unquenched effects. To account for such effects, we employ the modified Godfrey-Isgur model and introduce a screening potential. The resulting mass spectrum of the concerned higher $B_c$ states is then presented, showing significant deviations after considering the unquenched effects. This emphasizes the importance of considering the unquenched effects when studying of the higher $B_c$ mesons. Furthermore, we determine the corresponding spatial wave functions of these $B_c$ mesons, which have practical applications in subsequent studies of their decays. These decays include two-body Okuba-Zweig-Iizuka allowed strong decays, dipion transitions between $B_c$ mesons, radiative decays, and some typical weak decays. With the ongoing high-luminosity upgrade of the Large Hadron Collider, we expect the discovery of additional $B_c$ states in the near future. The knowledge gained from the mass spectrum and the different decay modes will undoubtedly provide valuable insights for future experimental explorations of these higher $B_c$ mesons.

    hep-phhep-exhep-latEPJC(2023)·34 citations
18. 18*

    Constraints on holographic QCD phase transitions from PTA observations

    Song He🇨🇳 · Li Li🇨🇳 · Sai Wang🇨🇳 · Shao-Jiang Wang🇨🇳

    The underlying physics of QCD phase transition in the early Universe remains largely unknown due to its strong-coupling nature during the quark-gluon plasma/hadron gas transition, yet a holographic model has been proposed to quantitatively fit the lattice QCD data while with its duration of the first-order phase transition (FoPT) left undetermined. At specific baryon chemical potential, the first-order QCD phase transition agrees with the observational constraint of baryon asymmetry. It, therefore, provides a scenario for phase transition gravitational waves (GWs) within the Standard Model of particle physics. If these background GWs could contribute dominantly to the recently claimed common-spectrum red noise from pulsar timing array (PTA) observations, the duration of this FoPT can be well constrained, and the associated primordial black holes are still allowed by current observations.

    hep-phastro-ph.COSCPMA(2025)·54 citations
19. 19*

    Can Planet 9 be an Axion Star?

    Haoran Di🇨🇳 · Haihao Shi🇨🇳

    The anomalous orbits of Trans-Neptunian Objects (TNOs) can be explained by the Planet 9 hypothesis. We propose that the Planet 9 can be an axion star. Axion stars are gravitational bound clusters condensed by QCD axions or axion-like particles (ALPs), which we call axions for brevity. We find that the probability of capturing an axion star by the solar system is the same order of magnitude as the probability of capturing a free floating planet (FFP), and even higher for the case of axion star, with axion star mass $5M_{\oplus }\approx 1.5\times 10^{-5}{M}_{\odot }$ and ${\Omega }_{\mathrm{AS}}/{\Omega }_{\mathrm{DM}}\simeq 1/10$. Although axion star can emit monochromatic signals through two-photon decay, we find that the frequency of decay photon is either not within the frequency range of the radio telescope, or the decay signal is too weak to be detected. Therefore, if Planet 9 is composed by an axion star, it may be difficult to distinguish it from an isolated primordial black hole by spontaneous decay of axion.

    hep-phastro-ph.COPRD(2023)·8 citations
20. 20*

    Heavy neutrino-antineutrino oscillations at the FCC-ee

    Stefan Antusch🇨🇭 · Jan Hajer🇵🇹 · Bruno M. S. Oliveira🇵🇹

    We discuss the impact of heavy neutrino-antineutrino oscillations (NNOs) on heavy neutral lepton (HNL) searches at proposed electron-positron colliders such as the future circular $e^{+}{e}^{-}$ collider (FCC-ee). During the $Z$ pole run, HNLs can be produced alongside a light neutrino or antineutrino that escapes detection and can decay into a charged lepton or antilepton together with an off-shell $W$ boson. In this case, signals of lepton number violation only show up in the final state distributions. We discuss how NNOs, a typical feature of collider-testable low-scale seesaw models where the heavy neutrinos form pseudo-Dirac pairs, modify such final state distributions. For example, the forward-backward asymmetry (FBA) of the reconstructed heavy (anti)neutrinos develops an oscillatory dependence on the HNL lifetime. We show that these oscillations can be resolvable for long-lived HNLs. We also discuss that when the NNOs are not resolvable, they can nevertheless significantly modify the theory predictions for FBAs and observables such as the ratio of the total number of HNL decays into ${\ell }^{-}$ over ones into ${\ell }^{+}$, in an interval of the angle~$\theta$ between the HNL and the beam axis. Our results show that NNOs should be included in collider simulations of HNLs at the FCCee.

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

    Deconfinement transition in the revolving bag model

    Kazuya Mameda🇯🇵 · Keiya Takizawa🇯🇵

    Based on the bag model, we revisit the deconfinement phase transition under rotation. On top of the usual rotational energy for noninteracting particles, we perturbatively analyze the revolution effect of the hadron bag, i.e., of the potential confining quarks. The revolution effect can be phenomenologically translated into the rotational correction to the QCD vacuum energy or the gluon condensate. We demonstrate that if the revolution effect is (is not) taken into account, the transition temperature increases (decreases) as the angular velocity increased. The `revolving bag model' provides a feasible explanation of the recent lattice simulations, contrary to effective models, showing that rotation favors the confined phase.

    hep-phnucl-thPLB(2023)·19 citations
22. 22*

    Finite Naturalness and Quark-Lepton Unification

    Pavel Fileviez Perez🇺🇸 · Clara Murgui🇺🇸 · Samuel Patrone🇺🇸 · Adriano Testa🇺🇸 · Mark B. Wise🇺🇸

    We study the implications of finite naturalness in Pati-Salam models where $SU(3{)}_C$ is embedded in $SU(4)$. For the minimal realization at low-scale of quark-lepton unification, which employs the inverse seesaw for neutrino masses, we find that radiative corrections to the Higgs boson mass are at least $\delta m_h^2/m_h^2\sim \mathcal{O}(10^4)$. The one-loop contributions to the Higgs mass are suppressed by four powers of the hypercharge gauge coupling. We find that for the vector leptoquarks the naively leading part of the two-loop corrections cancel. We assume the Dirac Yukawa couplings for neutrinos are equal to the up-type quark Yukawa couplings as predicted in the minimal theory for quark-lepton unification. Despite these findings, the two-loop corrections still dominate the finite naturalness bound. We mention a way to relax the lower bound on the vector leptoquark mass and have $\delta m_h^2/m_h^2\sim \mathcal{O}(10^2)$.

    hep-phPRD(2024)·12 citations
23. 23*

    A C++ program for estimating detector sensitivities to long-lived particles: Displaced Decay Counter

    Florian Domingo🇩🇪 · Julian Günther🇩🇪 · Jong Soo Kim🇿🇦 · Zeren Simon Wang🇹🇼

    A series of far-detector programs have been proposed for operation at various interaction points of the Large Hadron Collider during the upcoming runs. Investigating the potential and complementarity of these experiments for new-physics searches goes through the estimation of their sensitivity to specific long-lived particle models. Here, we present an integrated numerical tool written in the C++ language and called Displaced Decay Counter, which we have created to this end and which can be used in association with MadGraph5, Pythia8, or any other state-of-the-art Monte-Carlo collider simulation tool. Several far-detector models have been implemented within the program, accounting for the geometry and integrated luminosity of projected detectors. Additional or more accurate designs can be easily constructed through a dedicated interface. The functionality of this tool is exemplified through the discussion of three benchmark scenarios, which we consider for the validation of the implemented detector models.

    hep-phhep-exEPJC(2024)·13 citations
24. 24*

    Muonic Force and Neutrino Non-Standard Interactions at Muon Colliders

    Sudip Jana🇩🇪 · Sophie Klett🇩🇪

    The discovery of neutrino oscillations implies that neutrinos are massive and mixed, necessitating an extension of the Standard Model, which may require the introduction of non-standard neutrino interactions (NSI). We investigate the potential of a high-energy muon collider to probe such NSIs with muons, specifically focusing on muonic forces. By analyzing the monophoton signal from the process ${\mu }^{+}{\mu }^{-}\to \nu \overline{\nu }\gamma$, we explore four-fermion contact interactions involving two muons and two neutrinos. Moreover, we examine minimal models that generate scalar and vector-mediated NSIs and study their phenomenology. Projected sensitivities for the strength of NSIs, ${ϵ}_{\alpha \beta }^{\mu \mu }$, are presented at a 95$\%$ confidence level for a center-of-mass energy of 3 TeV and integrated luminosities of $\mathcal{L}=1$ and $10{\mathrm{ab}}^{-1}$, showcasing the complementarity between a muon collider and other experimental probes.

    hep-phhep-exPRD(2024)·17 citations
25. 25*

    The spin alignment of vector mesons with light front quarks

    Baochi Fu🇨🇳 · Fei Gao🇨🇳 · Yuxin Liu🇨🇳 · Huichao Song🇨🇳

    The global spin alignment of the vector meson has been observed in relativistic heavy ion collisions, but is still on hot debates in the theoretical community. Here we propose to apply the light front framework to explain this phenomenon since the light front form explicitly describes the hadron spin including both the quark spin and the orbital angular momentum. After applying the light front spinor, we find that the spin alignment in the polarization of vector mesons with ${\rho }_{00}>1/3$ can be naturally manifested and in particular, the obtained spin alignment for $\varphi$ meson is in good agreement with the experimental data. This implies that to explain the spin alignment it is important to properly include the contribution from the gluon interactions that are presented in terms of the orbital angular momentum of the hadron bound state.

    hep-phhep-exnucl-thPLB(2024)·13 citations
26. 26*

    Chiral fermion anomaly as a memory effect

    Adrián del Río🇪🇸 · Ivan Agullo🇺🇸

    We study the non-conservation of the chiral charge of Dirac fields between past and future null infinity due to the Adler-Bell-Jackiw chiral anomaly. In previous investigations \cite{dR21}, we found that this charge fails to be conserved if electromagnetic sources in the bulk emit circularly polarized radiation. In this article, we unravel yet another contribution coming from the non-zero, infrared "soft" charges of the external, electromagnetic field. This new contribution can be interpreted as another manifestation of the ordinary memory effect produced by transitions between different infrared sectors of Maxwell theory, but now on test quantum fields rather than on test classical particles. In other words, a flux of electromagnetic waves can leave a memory on quantum fermion states in the form of a permanent, net helicity. We elaborate this idea in both $1+1$ and $3+1$ dimensions. We also show that, in sharp contrast, gravitational infrared charges do not contribute to the fermion chiral anomaly.

    ↳ hep-thgr-qchep-phPRD(2023)·7 citations
27. 27*

    Search for axion-like particles through nuclear Primakoff production using the GlueX detector

    J.R. Pybus · T. Kolar · B. Devkota · P. Sharp · B. Yu · O. Hen · E. Piasetzky · S.N. Santiesteban · A. Schmidt · A. Somov · Y. Soreq · H. Szumila-Vance and 31 other authors

    We report on the results of the first search for the production of axion-like particles (ALP) via Primakoff production on nuclear targets using the GlueX detector. This search uses an integrated luminosity of 100 pb${}^{-1}\cdot$nucleon on a ${}^{12}$C target, and explores the mass region of 200 < $m_a$ < 450 MeV via the decay $X\to \gamma \gamma$. This mass range is between the ${\pi }^0$ and $\eta$ masses, which enables the use of the measured $\eta$ production rate to obtain absolute bounds on the ALP production with reduced sensitivity to experimental luminosity and detection efficiency. We find no evidence for an ALP, consistent with previous searches in the quoted mass range, and present limits on the coupling on the scale of $O$(1 TeV). We further find that the ALP production limit we obtain is hindered by the peaking structure of the non-target-related dominant background in GlueX, which we treat by using data on ${}^4$He to estimate and subtract these backgrounds. We comment on how this search can be improved in a future higher-statistics dedicated measurement.

    ↳ hep-exhep-phnucl-exPLB(2024)·17 citations
28. 28*

    Fast and effortless computation of profile likelihoods using CONNECT

    Andreas Nygaard🇩🇰 · Emil Brinch Holm🇩🇰 · Steen Hannestad🇩🇰 · Thomas Tram🇩🇰

    The frequentist method of profile likelihoods has recently received renewed attention in the field of cosmology. This is because the results of inferences based on the latter may differ from those of Bayesian inferences, either because of prior choices or because of non-Gaussianity in the likelihood function. Consequently, both methods are required for a fully nuanced analysis. However, in the last decades, cosmological parameter estimation has largely been dominated by Bayesian statistics due to the numerical complexity of constructing profile likelihoods, arising mainly from the need for a large number of gradient-free optimisations of the likelihood function. In this paper, we show how to accommodate the computational requirements of profile likelihoods using the publicly available neural network framework CONNECT together with a novel modification of the gradient-based $basin$-$hopping$ optimisation algorithm. Apart from the reduced evaluation time of the likelihood due to the neural network, we also achieve an additional speed-up of 1$-$2 orders of magnitude compared to profile likelihoods computed with the gradient-free method of $simulated$ $annealing$, with excellent agreement between the two. This allows for the production of typical triangle plots normally associated with Bayesian marginalisation within cosmology (and previously unachievable using likelihood maximisation because of the prohibitive computational cost). We have tested the setup on three cosmological models: the $\Lambda$CDM model, an extension with varying neutrino mass, and finally a decaying cold dark matter model. Given the default precision settings in CONNECT, we achieve a high precision in ${\chi }^2$ with a difference to the results obtained by CLASS of $\Delta {\chi }^2\approx 0.2$ (and, importantly, without any bias in inferred parameter values) $-$ easily good enough for profile likelihood analyses.

    ↳ astro-ph.COastro-ph.IMhep-phJCAP(2023)·17 citations
29. 29*

    Identities amongst the Two Loop Partial Amplitudes of Yang-Mills theory

    David C. Dunbar🇬🇧

    We characterise possible identities among the two-loop partial amplitudes of gluon scattering in Yang-Mills theory. We use known amplitudes in an exhaustive search to identify potential new relations. We find two candidate relations which may extend to all-$n$ amplitudes.

    ↳ hep-thhep-phJHEP(2023)·7 citations
30. 30*

    Indirect dark matter search in the Galactic Centre with IceCube

    Nhan Chau · Juan A. Aguilar (for the IceCube Collaboration)

    It is assumed that dark matter can annihilate or decay into Standard Model particles which then can produce a neutrino flux detectable at IceCube. Such a signal can be emitted from the Galactic Center thanks to the high density of dark matter abundance being gravitationally captured. This analysis aims at searching for neutrino signals from dark matter annihilation and decay in the Galactic Center using $\sim$9 years of IceCube-DeepCore data with an optimized selection for low energy. In this contribution, we present the sensitivities on the thermally averaged dark matter self-annihilation cross-section for dark matter masses ranging from 5 GeV up to 8 TeV.

    ↳ astro-ph.HEhep-phPoS(2023)·5 citations
31. 31*

    Propagation Speed of Gravitational Wave in Scalar--Einstein--Gauss-Bonnet Gravity

    Shin'ichi Nojiri🇯🇵 · Sergei. D. Odintsov🇪🇸

    The propagation speed of the gravitational wave in scalar--Einstein--Gauss-Bonnet (sEGB) gravity is generally different from that of light. Using differential equation conditions for the speed of gravitational waves to coincide with the light speed in the expanding universe, we constructed a general class of sEGB gravities where this condition is satisfied and realistic inflation occurs. It is demonstrated that the condition that the speed of gravitational wave coincides with that of the light in the Friedmann-Lemaître-Robertson-Walker (FRLW) universe is always different from the condition for gravitational wave speed in the sEGB black hole background. Moreover, it is shown that when gravitational wave speed in sEGB black hole is equal to the speed of light the black hole spacetime geometry is changing too so that formally there is no solution for such sEGB black hole. This may indicate that sEGB black holes hardly can be considered as realistic black holes unless some reasonable scenario to make gravitational wave speed to be equal to that of light is proposed, at least asymptotically.

    ↳ gr-qcastro-ph.COhep-phhep-thNPB(2024)·26 citations
32. 32*

    On the inflationary interpretation of the nHz gravitational-wave background

    Lorenzo Frosina🇮🇹 · Alfredo Urbano🇮🇹

    We construct a single-field model of inflation that achieves remarkable agreement with Planck and BICEP/Keck cosmological observations. The model, via the presence of an ultra-slow-roll phase, generates a sizable scalar-induced gravitational wave (GW) signal at nHz frequencies. We elucidate the distinctive features of this signal concerning its connection to the recent measurement of the low-frequency GW background reported by the NANOGrav collaboration.

    ↳ astro-ph.COgr-qchep-phPRD(2023)·67 citations
33. 33*

    Late-time Cosmology without Dark Sector but with Closed String Massless Sector

    Hocheol Lee🇰🇷 · Jeong-Hyuck Park🇰🇷 · Liliana Velasco-Sevilla🇰🇷 · Lu Yin🇰🇷

    We explore the possibility of solving the dark energy and the coincidence problems by postulating the massless sector of closed strings. This sector constitutes the gravitational multiplet of string theory and, when applied to four-dimensional cosmology, predicts that \textit{the expansion of an open Universe defined in string frame is readily accelerating}. We confront the prediction with the late-time cosmological data of Type Ia supernovae and quasar absorption spectrum, which probe the evolutions of the Hubble parameter and possibly the fine-structure constant. We report that these observations are in admirable agreement with the prediction without any dark sector or coincidence problem. We estimate the Hubble constant, $H_0\simeq 71.2\pm 0.2km/s/Mpc$.

    ↳ hep-thgr-qchep-phPLB(2025)·8 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.