Tue·Feb 2, 2021Tuesday·February 2, 2021

1. 01*

   MeV astronomy with Herwig?

   Peter Reimitz🇧🇷

   GeV-scale dark matter is an increasingly attractive target for direct detection, indirect detection, and collider searches. Especially for masses in the MeV to GeV range, indirect detection is expected to give a leading constraint. In that range, dark matter annihilations into hadronic final states produce a challenging zoo of light hadronic resonances. With an update of Herwig7, we provide a modeling of these processes and study energy spectra from annihilation through a vector mediator. We cover dark matter masses between 250 MeV and 5 GeV and include an error estimate. This opens up new opportunities for fully studying indirect detection signals for hidden dark matter sectors with vector mediators in the sub-GeV range.

   hep-phPoS(2021)·7 citations
2. 02*

   The mass radius of the proton

   Dmitri E. Kharzeev🇺🇸

   The mass radius is a fundamental property of the proton that so far has not been determined from experiment. Here we show that the mass radius of the proton can be rigorously defined through the formfactor of the trace of the energy-momentum tensor (EMT) of QCD in the weak gravitational field approximation, as appropriate for this problem. We then demonstrate that the scale anomaly of QCD enables the extraction of the formfactor of the trace of the EMT from the data on threshold photoproduction of $J/\psi$ and ${\rm Y}$ quarkonia, and use the recent GlueX Collaboration data to extract the r.m.s. mass radius of the proton ${\mathrm{R}}_{\mathrm{m}}=0.55\pm 0.03\mathrm{fm}$. The extracted mass radius is significantly smaller than the charge radius of the proton ${\mathrm{R}}_{\mathrm{C}}=0.8409\pm 0.0004\mathrm{fm}$. We attribute this difference to the interplay of asymptotic freedom and spontaneous breaking of chiral symmetry in QCD, and outline future measurements needed to determine the mass radius more precisely.

   hep-phhep-latnucl-exnucl-thPRD(2021)·143 citations
3. 03*

   How to observe the QCD instanton/sphaleron processes at hadron colliders?

   Edward Shuryak🇺🇸 · Ismail Zahed🇺🇸

   The instanton/sphaleron processes involve gauge fields with changing topology through a nonzero variation of the Chern-Simons number $\delta N_{CS}=\pm 1$. In QCD this leads to the production of $2N_f\delta N_{CS}$ units of axial charge, and in the electroweak theory to the production of 12 fermions, with $\Delta B=\delta L=3$ units of baryon and lepton number, a key mechanism in baryogenesis. While this is all known for a long time, and is one of the pillars of the nonperturbative theory of the QCD vacuum, to see these phenomena directly in colliders remains an unfulfilled promise. Motivated by the recent CERN workshop on the topic, we review the field. We also put forward our own suggestions to utilize double-diffractive (or Pomeron-Pomeron) collisions to this goal, which maximizes the entrance factor and minimizes the backgrounds. We consider separately clusters of small ($M=3-10\mathrm{GeV}$), medium ($10-30\mathrm{GeV}$) and high $M\sim 100\mathrm{GeV}$ invariant masses. Among the proposed signals are specific flavor combination of channels, originating from well-defined 6-, 8- and 10-quark-antiquark operators, as well as correlation of quark chiralities to be potentially detected via $\Lambda$ hyperon decays.

   hep-ph15 citations
4. 04*

   Constraining axion-like particles using the white dwarf initial-final mass relation

   Matthew J. Dolan🇦🇺 · Frederick J. Hiskens🇦🇺 · Raymond R. Volkas🇦🇺

   Axion-like particles (ALPs), a class of pseudoscalars common to many extensions of the Standard Model, have the capacity to drain energy from the interiors of stars. Consequently, stellar evolution can be used to derive many constraints on ALPs. We study the influence that keV-MeV scale ALPs which interact exclusively with photons can exert on the helium-burning shells of asymptotic giant branch stars, the late-life evolutionary phase of stars with initial masses less than $8M_{\odot }$. We establish the sensitivity of the final stellar mass to such energy-loss for ALPs with masses currently permitted by stellar evolution bounds. A semi-empirical constraint on the white dwarf initial-final mass relation (IFMR) derived from observation of double white dwarf binaries is then used to exclude part of a currently unconstrained region of ALP parameter space, the cosmological triangle. The derived constraint relaxes when the ALP decay length becomes shorter than the width of the helium-burning shell. Other potential sources for stellar constraints on ALPs are also discussed.

   hep-phastro-ph.HEastro-ph.SRJCAP(2021)·48 citations
5. 05*

   Thermoelectric behaviour of hot collisional and magnetized QCD medium from an effective kinetic theory

   Manu Kurian🇮🇳

   The thermoelectric behaviour of quark-gluon plasma has been studied within the framework of an effective kinetic theory by adopting a quasiparticle model to incorporate the thermal medium effects. The thermoelectric response of the medium has been quantified in terms of the Seebeck coefficient. The dependence of the collisional aspects of the QCD medium on the Seebeck coefficient has been estimated by utilizing relaxation time approximation and Bhatnagar-Gross-Krook collision kernels in the effective Boltzmann equation. The thermoelectric coefficient is seen to depend on the quark chemical potential and collision aspects of the medium. Besides, the thermoelectric effect has been explored in a magnetized medium and the respective transport coefficients, such as magnetic field-dependent Seebeck coefficient and Nernst coefficient, have been estimated. The impacts of hot QCD medium interactions incorporated through the effective model and the magnetic field on the thermoelectric responses of the medium have been observed to be more prominent in the temperature regimes not very far from the transition temperature.

   hep-phPRD(2021)·20 citations
6. 06*

   Energy and mass dependencies for the characteristics of $p_T$ regions observed at LHC energies

   Mais Suleymanov🇦🇿

   The $p_T$ distributions of the $K^0$- and $\varphi$ - mesons produced in the $pp$ collisions at $\sqrt{s}=2.76TeV$ have been analyzed by fitting them using the exponential function. It was observed that the distributions contain several $p_T$ regions similar to the cases with the charged particles, ${\pi }^0$- and $\eta$- mesons produced in the same events. These regions could be characterized using three variables: the length of the region $L_K^c$ and free fitting parameters $a_K^c$ and $b_K^c$. It was observed that the values of the parameters as a function of energy grouped around certain lines and there are jump-like changes. These observations together with the effect of existing the several $p_T$ regions can say on discrete energy dependencies for the $L_K^c$ , $a_K^c$ and $b_K^c$. The lengths of the regions increase with the mass of the particles. This increase gets stronger with energy. The mass dependencies of the parameters $a_K^c$ and $b_K^c$ show a regime change at a mass $\simeq 500MeV/c^2$. According to the phenomenology of string theory, these results could be explained by two processes occurring simultaneously: string hadronization and string breaking. In the experiment we can only measure the spectrum of the hadronized particles, since we cannot access the spectrum of the strings themselves. The string breaking effect could be a signal of string formations and the reason behind the observation of several $p_T$ regions and the jump-like changes for the characteristics of the regions.

   hep-phnucl-exPhys.Part.Nucl.(2023)·4 citations
7. 07*

   Neutrino-nucleon DIS from Holographic QCD: PDFs of sea and valence quarks, form factors, and structure functions of the proton

   Kiminad A. Mamo🇺🇸 · Ismail Zahed🇺🇸

   We discuss unpolarized neutrino- and anti-neutrino-nucleon deep inelastic scattering (DIS) using a chiral doublet of baryonic sources with explicit symmetry breaking, in a slice of AdS${}_5$ with both a hard and soft wall. We explicitly derive the direct and transition form factors for the vector and axial-vector currents for the holographic dual of a proton and neutron. We use them to derive the s-channel structure functions for neutrino and anti-neutrino scattering on a proton and neutron in bulk. The t-channel contributions stemming from the Pomeron and Reggeon exchanges are also evaluated explicitly. The pertinent even and odd structure functions in the limit of large and small parton momentum fraction $x$ are given. The results allow for the extraction of the nonperterbative parton distribution functions carried by the sea and valence quarks both at large-x and small-x regimes. Our holographic PDF sets compare well with LHAPDF and CTEQ PDF sets in the large-x and small-x regimes in the intermediate range of $Q^2<10\mathrm{Ge}{\mathrm{V}}^2$.

   hep-phhep-thnucl-thPRD(2021)·8 citations
8. 08*

   Isospin Symmetry of Fragmentation Functions

   Kai-bao Chen🇨🇳 · Zuo-tang Liang🇨🇳 · Yan-lei Pan🇨🇳 · Yu-kun Song🇨🇳 · Shu-yi Wei🇮🇹

   We make a systematic study of the isospin symmetry of fragmentation functions by taking decay contributions into account. We assume the isospin symmetry in strong interactions and show that in the unpolarized case the isospin symmetry is held for fragmentation functions of $\Lambda$ and only tiny violations are allowed for other hadrons such as nucleon and pions due to the contributions from weak decays. We present a rough estimate of the magnitudes of such violations. In the polarized case, we show that the isospin symmetry violation for $\Lambda$ production should be tiny and the recent Belle data on the transverse polarization of $\Lambda$ can be reproduced if the isospin symmetry is kept in the corresponding polarized fragmentation functions.

   hep-phPLB(2021)·31 citations
9. 09*

   Alternative method of generating gamma rays with orbital angular momentum

   Minoru Tanaka🇯🇵 · Noboru Sasao🇯🇵

   We propose a new method of generating gamma rays with orbital angular momentum (OAM). Accelerated partially-stripped ions are used as an energy up-converter. Irradiating an optical laser beam with OAM on ultrarelativistic ions, they are excited to a state of large angular momentum. Gamma rays with OAM are emitted in their deexcitation process. We examine the excitation cross section and deexcitation rate.

   hep-phIJMPE(2021)·4 citations
10. 10*

    Predicting a new resonance as charmed-strange baryonic analog of $D_{s0}^{\ast }(2317)$

    Si-Qiang Luo🇨🇳 · Bing Chen🇨🇳 · Xiang Liu🇨🇳 · Takayuki Matsuki🇯🇵

    By an unquenched quark model, we predict a charmed-strange baryon state, namely, the ${\Omega }_{c0}^d(1P,1/2^{-})$. Its mass is predicted to be 2945 MeV, which is below the ${\Xi }_c\bar{K}$ threshold due to the nontrivial coupled-channel effect. So the ${\Omega }_{c0}^d(1P,1/2^{-})$ state could be regraded as the analog of the charmed-strange meson $D_{s0}^{\ast }(2317)$. It is a good opportunity for the running Belle II experiment to search for this state in the ${\Omega }_c^{(\ast )}\gamma$ mass spectrum experiment in the future.

    hep-phhep-exPRD(2021)·34 citations
11. 11*

    The hadronic $\tau$ decay ${\tau }^{-}\to K_1^{-}{\nu }_{\tau }\to (K^{-}\omega ){\nu }_{\tau }\to (K^{-}{\pi }^{+}{\pi }^{-}{\pi }^0){\nu }_{\tau }$ and the axial vector mixing angle

    K. Hayasaka🇯🇵 · Z. Huang🇫🇷 · E. Kou🇫🇷

    We propose to measure the ${\tau }^{-}\to K_1^{-}{\nu }_{\tau }\to (K^{-}\omega ){\nu }_{\tau }\to (K^{-}{\pi }^{+}{\pi }^{-}{\pi }^0){\nu }_{\tau }$ decay in order to determine the $K_1$ axial vector mixing angle ${\theta }_{K_1}$. We derive, for the first time, the differential decay rate formula for this decay mode. Using the obtained result, we perform a sensitivity study for the Belle (II) experiment. We will show that the $K^{-}{\pi }^{+}{\pi }^{-}{\pi }^0$ spectrum of the ${\tau }^{-}\to K_1^{-}{\nu }_{\tau }\to (K^{-}\omega ){\nu }_{\tau }\to (K^{-}{\pi }^{+}{\pi }^{-}{\pi }^0){\nu }_{\tau }$ decay can discriminate the two solutions ${\theta }_{K_1}=\sim 30^{\circ }$ or $\sim 60^{\circ }$ observed in the other measurements.

    hep-phhep-exEPJC(2021)·4 citations
12. 12*

    Probing the doubly-charged Higgs with Muonium to Antimuonium Conversion Experiment

    Chengcheng Han🇨🇳 · Da Huang🇨🇳 · Jian Tang🇨🇳 · Yu Zhang🇨🇳

    The spontaneous muonium-to-antimuonium conversion is one of the interesting charged lepton flavor violation processes. MACE is the next generation experiment to probe such a phenomenon. In models with a triplet Higgs to generate neutrino masses, such as Type-II seesaw and its variant, this process can be induced by the doubly-charged Higgs contained in it. In this article, we study the prospect of MACE to probe these models via the muonium-to-antimuonium transitions. After considering the limits from ${\mu }^{+}\to e^{+}\gamma$ and ${\mu }^{+}\to e^{+}{e}^{-}{e}^{+}$, we find that MACE could probe a parameter space for the doubly-charged Higgs which is beyond the reach of LHC and other flavor experiments.

    hep-phhep-exPRD(2021)·27 citations
13. 13*

    Speeding up MadGraph5_aMC@NLO

    Kiran Ostrolenk🇬🇧 · Olivier Mattelaer🇧🇪

    In this paper we will describe two new optimisations implemented in MadGraph5_aMC@NLO, both of which are designed to speed-up the computation of leading-order processes (for any model). First we implement a new method to evaluate the squared matrix element, dubbed helicity recycling, which results in factor of two speed-up. Second, we have modified the multi-channel handling of the phase-space integrator providing tremendous speed-up for VBF-like processes (up to thousands times faster).

    hep-phEPJC(2021)·42 citations
14. 14*

    Neutrino scattering off a black hole surrounded by a magnetized accretion disk

    Maxim Dvornikov (IZMIRAN)🇷🇺

    We study the neutrino scattering off a rotating black hole with a realistic accretion disk permeated by an intrinsic magnetic field. Neutrino trajectories in curved spacetime as well as the particle spin evolution in dense matter of an accretion disk and in the magnetic field are accounted for exactly. We obtain the fluxes of outgoing ultrarelativistic neutrinos taking into account the change of the neutrino polarization owing to spin oscillations. Using the conservative value of the neutrino magnetic moment and realistic radial distributions of the matter density and the magnetic field strength, we get that these fluxes are reduced by several percent compared to the case when no spin oscillations are accounted for. In some situations, there are spikes in the neutrino fluxes because of the neutrino interaction with the rotating plasma of an accretion disk. Taking into account the uncertainties in the astrophysical neutrino fluxes, the predicted effects turn out to be quite small to be observed with the current neutrino telescopes.

    hep-phastro-ph.HEgr-qcJCAP(2021)·15 citations
15. 15*

    The $\Lambda (1405)$ in resummed chiral effective field theory

    X.-L. Ren🇩🇪 · E. Epelbaum🇩🇪 · J. Gegelia🇩🇪 · Ulf-G. Meißner🇩🇪

    We study the unitarized meson-baryon scattering amplitude at leading order in the strangeness $S=-1$ sector using time-ordered perturbation theory for a manifestly Lorentz-invariant formulation of chiral effective field theory. By solving the coupled-channel integral equations with the full off-shell dependence of the effective potential and applying subtractive renormalization, we analyze the renormalized scattering amplitudes and obtain the two-pole structure of the $\Lambda (1405)$ resonance. We also point out the necessity of including higher-order terms.

    hep-phnucl-thEPJC(2021)·11 citations
16. 16*

    Pair invariant mass spectrum and polarization asymmetry in the event generation of gamma-ray conversions

    Denis Bernard🇫🇷

    We examine the dielectron invariant mass spectrum and the variation of the polarization asymmetry as a function of that mass in the event generator of the five-dimensional Bethe-Heitler differential cross section of the conversion of linearly polarized photons that we have implemented recently as a Geant4 Physics Model. We compare the results obtained with simulated samples to analytical expressions. Studies of $b\to s\gamma$ decays at LHC and Belle II experiments could provide hints of physics beyond the standard model in flavor-changing neutral current processes; issues have been reported in the simulation of the properties of the background induced by genuine $\gamma$-ray conversions in their detectors. Our results demonstrate that using the five-dimensional model would help solve these issues.

    hep-phphysics.data-anNucl.Instrum.Meth.A(2021)·1 citation
17. 17*

    Combine and Conquer: Event Reconstruction with Bayesian Ensemble Neural Networks

    Jack Y. Araz🇬🇧 · Michael Spannowsky🇬🇧

    Ensemble learning is a technique where multiple component learners are combined through a protocol. We propose an Ensemble Neural Network (ENN) that uses the combined latent-feature space of multiple neural network classifiers to improve the representation of the network hypothesis. We apply this approach to construct an ENN from Convolutional and Recurrent Neural Networks to discriminate top-quark jets from QCD jets. Such ENN provides the flexibility to improve the classification beyond simple prediction combining methods by linking different sources of error correlations, hence improving the representation between data and hypothesis. In combination with Bayesian techniques, we show that it can reduce epistemic uncertainties and the entropy of the hypothesis by simultaneously exploiting various kinematic correlations of the system, which also makes the network less susceptible to a limitation in training sample size.

    hep-phJHEP(2021)·37 citations
18. 18*

    Quark condensates and magnetization in chiral perturbation theory in a uniform magnetic field

    Prabal Adhikari🇺🇸 · Jens O. Andersen🇳🇴

    We reconsider the problem of calculating the vacuum free energy (density) of QCD and the shift of the quark condensates in the presence of a uniform background magnetic field using two-and-three-flavor chiral perturbation theory ($\chi$PT). Using the free energy, we calculate the degenerate, light quark condensates in the two-flavor case and the up, down and strange quark condensates in the three-flavor case. We also use the vacuum free energy to calculate the (renormalized) magnetization of the QCD vacuum, which shows that it is paramagnetic. We find that the three-flavor light-quark condensates and (renormalized) magnetization are improvements on the two-flavor results. We also find that the average light quark condensate is in agreement with the lattice up to $eB=0.2\mathrm{Ge}{\mathrm{V}}^2$, and the (renormalized) magnetization is in agreement up to $eB=0.3\mathrm{Ge}{\mathrm{V}}^2$, while three-flavor $\chi$PT, which gives a non-zero shift in the difference between the light quark condensates unlike two-flavor $\chi$PT, underestimates the difference compared to lattice QCD.

    hep-phhep-lathep-th7 citations
19. 19*

    Dark matter from an even lighter QCD axion: trapped misalignment

    Luca Di Luzio🇩🇪 · Belen Gavela🇪🇸 · Pablo Quilez🇩🇪 · Andreas Ringwald🇩🇪

    We show that dark matter can be accounted for by an axion that solves the strong CP problem, but is much lighter than usual due to a $Z_{\mathcal{N}}$ symmetry. The whole mass range from the canonical QCD axion down to the ultra-light regime is allowed, with $3\le \mathcal{N}\lesssim 65$. This includes the first proposal of a "fuzzy dark matter" QCD axion with $m_a\sim 10^{-22}$ eV. A novel misalignment mechanism occurs --{\it trapped misalignment}-- due to the peculiar temperature dependence of the $Z_{\mathcal{N}}$ axion potential. The dark matter relic density is enhanced because the axion field undergoes two stages of oscillations: it is first trapped in the wrong minimum, which effectively delays the onset of true oscillations. Trapped misalignment is more general than the setup discussed here, and may hold whenever an extra source of Peccei-Quinn breaking appears at high temperatures. Furthermore, it will be shown that trapped misalignment can dynamically source the recently proposed kinetic misalignment mechanism. All the parameter space is within tantalizing reach of the experimental projects for the next decades. For instance, even Phase I of CASPEr-Electric could discover this axion.

    hep-phastro-ph.COJCAP(2021)·150 citations
20. 20*

    Light Higgs boson from multi-phase criticality in dynamical symmetry breaking

    Kristjan Kannike🇪🇪 · Luca Marzola🇪🇪 · Martti Raidal🇪🇪 · Alessandro Strumia🇮🇹

    The Coleman-Weinberg mechanism can realise different phases of dynamical symmetry breaking. In each phase a combination of scalars, corresponding to the pseudo-Goldstone boson of scale invariance, has a loop-suppressed mass. We show that additional scalars, beyond the pseudo-Goldstone bosons, can become light at critical points in the parameter space where two different phases co-exist. We present a minimal implementation of the mechanism in multi-scalar models, detailing how loop-suppressed masses and mixings can be computed. We discuss realisations of the resulting multi-phase criticality principle and its relevance to the case of the Higgs boson.

    hep-phPLB(2021)·16 citations
21. 21*

    REvolver: Automated running and matching of couplings and masses in QCD

    Andre H. Hoang🇦🇹 · Christopher Lepenik🇦🇹 · Vicent Mateu🇪🇸

    In this article we present REvolver, a C++ library for renormalization group evolution and automatic flavor matching of the QCD coupling and quark masses, as well as precise conversion between various quark mass renormalization schemes. The library systematically accounts for the renormalization group evolution of low-scale short-distance masses which depend linearly on the renormalization scale and sums logarithmic terms of high and low scales that are missed by the common logarithmic renormalization scale evolution. The library can also be accessed through Mathematica and Python interfaces and provides renormalization group evolution for complex renormalization scales as well.

    hep-phComput.Phys.Commun.(2022)·40 citations
22. 22*

    Origin and Resummation of Threshold Logarithms in the Lattice QCD Calculations of PDFs

    Xiang Gao🇺🇸 · Kyle Lee🇺🇸 · Swagato Mukherjee🇺🇸 · Charles Shugert🇺🇸 · Yong Zhao🇺🇸

    Many present lattice QCD approaches to calculate the parton distribution functions (PDFs) rely on a factorization formula or effective theory expansion of certain Euclidean matrix elements in boosted hadron states. In the quasi- and pseudo-PDF methods, the matching coefficient in the factorization or expansion formula includes large logarithms near the threshold, which arise from the subtle interplay of collinear and soft divergences of an underlying 3D momentum distribution. We use the standard prescription to resum such logarithms in the Mellin-moment space at next-to-leading logarithmic accuracy, which also accounts for the DGLAP evolution, and we show that it can suppress the PDF at large $x$. Unlike the deep inelastic scattering and Drell-Yan cross sections, the resummation formula is away from the Landau pole. We then apply our formulation to reanalyze the recent lattice results for the pion valence PDF, and find that within the current data sensitivity, the effect of threshold resummation is marginal for the accessible moments and the PDF at large $x$.

    hep-phhep-lathep-thnucl-thPRD(2021)·62 citations
23. 23*

    MICROSCOPE's constraint on a short-range fifth force

    Joel Bergé🇫🇷 · Martin Pernot-Borràs🇫🇷 · Jean-Philippe Uzan🇫🇷 · Philippe Brax🇫🇷 · Ratana Chhun🇫🇷 · Gilles Métris🇫🇷 · Manuel Rodrigues🇫🇷 · Pierre Touboul🇫🇷

    The MICROSCOPE experiment was designed to test the weak equivalence principle in space, by comparing the low-frequency dynamics of cylindrical "free-falling" test masses controlled by electrostatic forces. We use data taken during technical sessions aimed at estimating the electrostatic stiffness of MICROSCOPE's sensors to constrain a short-range Yukawa deviation from Newtonian gravity. We take advantage of the fact that in the limit of small displacements, the gravitational interaction (both Newtonian and Yukawa-like) between nested cylinders is linear, and thus simply characterised by a stiffness. By measuring the total stiffness of the forces acting on a test mass as it moves, and comparing it with the theoretical electrostatic stiffness (expected to dominate), it is a priori possible to infer constraints on the Yukawa potential parameters. However, we find that measurement uncertainties are dominated by the gold wires used to control the electric charge of the test masses, though their related stiffness is indeed smaller than the expected electrostatic stiffness. Moreover, we find a non-zero unaccounted for stiffness that depends on the instrument's electric configuration, hinting at the presence of patch-field effects. Added to significant uncertainties on the electrostatic model, they only allow for poor constraints on the Yukawa potential. This is not surprising, as MICROSCOPE was not designed for this measurement, but this analysis is the first step to new experimental searches for non-Newtonian gravity in space.

    ↳ gr-qchep-phClass.Quant.Grav.(2022)·24 citations
24. 24*

    Dibaryon with highest charm number near unitarity from lattice QCD

    Yan Lyu🇨🇳 · Hui Tong🇨🇳 · Takuya Sugiura🇯🇵 · Sinya Aoki🇯🇵 · Takumi Doi🇯🇵 · Tetsuo Hatsuda🇯🇵 · Jie Meng🇨🇳 · Takaya Miyamoto🇯🇵

    A pair of triply charmed baryons, ${\Omega }_{ccc}{\Omega }_{ccc}$, is studied as an ideal dibaryon system by (2+1)-flavor lattice QCD with nearly physical light-quark masses and the relativistic heavy quark action with the physical charm quark mass. The spatial baryon-baryon correlation is related to their scattering parameters on the basis of the HAL QCD method. The ${\Omega }_{ccc}{\Omega }_{ccc}$ in the ${}^1{S}_0$ channel taking into account the Coulomb repulsion with the charge form factor of ${\Omega }_{ccc}$ leads to the scattering length $a_0^{\mathrm{C}}\simeq -19\text{fm}$ and the effective range $r_{\mathrm{eff}}^{\mathrm{C}}\simeq 0.45\text{fm}$. The ratio $r_{\mathrm{eff}}^{\mathrm{C}}/a_0^{\mathrm{C}}\simeq -0.024$, whose magnitude is considerably smaller than that of the dineutron ($-0.149$), indicates that ${\Omega }_{ccc}{\Omega }_{ccc}$ is located in the unitary regime.

    ↳ hep-lathep-exhep-phnucl-ex+1PRL(2021)·94 citations
25. 25*

    $\eta$ mesons in hot magnetized nuclear matter

    Rajesh Kumar🇮🇳 · Arvind Kumar🇮🇳

    The $\eta N$ interactions are investigated in the hot magnetized asymmetric nuclear matter using chiral SU(3) model and chiral perturbation theory (ChPT). In the chiral model, the in-medium properties of $\eta$-meson are calculated by the medium modified scalar densities under the influence of an external magnetic field. Further, in the combined approach of chiral model and ChPT, off-shell contributions of $\eta N$ interactions are evaluated from the ChPT effective $\eta N$ Lagrangian, and the in-medium effect of scalar densities are incorporated from the chiral SU(3) model. We observe a significant effect of magnetic field on the in-medium mass and optical potential of $\eta$ meson. We observe a deeper mass-shift in the combined approach of ChPT and chiral model compared to the effect of solo chiral SU(3) model. In both approaches, no additional mass-shift is observed due to the uncharged nature of $\eta$ mesons in the presence of magnetic field.

    ↳ nucl-thhep-phCPC(2022)·2 citations
26. 26*

    Searching for eV-mass Axion-like Particles with Cross Correlations between Line Intensity and Weak Lensing Maps

    Masato Shirasaki🇯🇵

    We study cross correlations between line intensity and weak lensing maps to search for axion-like particles (ALPs). Radiative decay of eV-mass ALPs can contribute to cosmic background emissions at optical and infrared wavelengths. Line intensity mapping is a unique means of measuring the background emission at a given photon frequency. If ALPs constitute the abundance of cosmic dark matter, line intensity maps can correlate with large-scale structures probed by weak gravitational lensing effects in galaxy imaging surveys. We develop a theoretical framework to predict the cross correlation. We then explore potentiality of probing ALPs with the cross correlation in upcoming galaxy-imaging and spectral surveys. Assuming SPHEREx and the Vera Rubin Observatory's Legacy Survey of Space and Time (LSST), we find that the cross correlation by the ALP decay can be greater than the astrophysical-line counterparts at wavelength of $\sim 3000\mathrm{nm}$ for ALPs with a particle mass of $m_a\sim 1\mathrm{eV}$ and a particle-to-two-photons coupling of $g_{a\gamma \gamma }\sim 1\times 10^{-11}{\mathrm{GeV}}^{-1}$. We also predict that a null detection of the cross correlation can place a $2\sigma$-level upper bound of g_{a\gamma\gamma} \lower.5ex\hbox{\; \buildrel < \over \sim \;} 10^{-11}\, \mathrm{GeV}^{-1} for eV-mass ALPs, improving the current constraint by a factor of $\sim 10$. We then make a forecast of expected constraints on ALP parameters in SPHEREx and LSST by Fisher analysis, providing a guideline of searching for the ALP decay with the large-scale structure data.

    ↳ astro-ph.COhep-phPRD(2021)·13 citations
27. 27*

    Direct Measurements of Neutrino Mass

    Joseph A. Formaggio🇺🇸 · André Luiz C. de Gouvêa🇺🇸 · R. G. Hamish Robertson🇺🇸

    The turn of the 21st century witnessed a sudden shift in our fundamental understanding of particle physics. While the minimal Standard Model predicts that neutrino masses are exactly zero, the discovery of neutrino oscillations proved the Standard Model wrong. Neutrino oscillation measurements, however, do not shed light on the scale of neutrino masses, nor the mechanism by which those are generated. The neutrino mass scale is most directly accessed by studying the energy spectrum generated by beta decay or electron capture -- a technique dating back to Enrico Fermi's formulation of radioactive decay. In this Article, we review the methods and techniques -- both past and present -- aimed at measuring neutrino masses kinematically. We focus on recent experimental developments that have emerged in the past decade, overview the spectral refinements that are essential in the treatment of the most sensitive experiments, and give a simple yet effective protocol for estimating the sensitivity. Finally, we provide an outlook of what future experiments might be able to achieve.

    ↳ nucl-exhep-phPhys.Rept.(2021)·149 citations
28. 28*

    Antikaon-induced $K_1(1270{)}^{+}$ meson production on nuclei near threshold

    E. Ya. Paryev🇷🇺

    We study the inclusive strange axial-vector meson $K_1(1270{)}^{+}$ production in $K^{-}A$ reactions at near-threshold laboratory incident antikaon momenta within a nuclear spectral function approach, which describes incoherent direct $K_1(1270{)}^{+}$ meson production in $K^{-}$ meson--proton $K^{-}p\to K_1(1270{)}^{+}{\Xi }^{-}$ production processes and accounts for three different options for its in-medium mass shift (or for its effective scalar potential) at central density ${\rho }_0$. We calculate the absolute differential and total cross sections for the production of $K_1(1270{)}^{+}$ mesons on ${}^{12}$C and ${}^{184}$W target nuclei at laboratory angles of 0${}^{\circ }$--45${}^{\circ }$ by $K^{-}$ mesons with momenta of 2.5, 2.8 and 3.5 GeV/c, which are close to the threshold momentum ($\approx$ 2.95 GeV/c) for $K_1(1270{)}^{+}$ meson production off the free target proton at rest. The intrinsic properties of carbon and tungsten target nuclei have been described in terms of their spectral functions, which take into account the momenta of target protons and the energies of their separation from the considered nuclei. We show that the differential and total (absolute and relative) $K_1(1270{)}^{+}$ antikaon-induced production cross sections at initial momenta not far from threshold -- at momenta $\sim$ 2.8--3.5 GeV/c, at which there is yet no strong drop in their strength, reveal a distinct sensitivity to changes in the in-medium shift of the $K_1(1270{)}^{+}$ mass, studied in the paper, both in the $K_1(1270{)}^{+}$ meson low-momentum (0.1--1.0 GeV/c) and in its full-momentum ranges. This would permit evaluating this shift. Experimental data necessary for this aim can be obtained in a dedicated experiment at the J-PARC Hadron Experimental Facility.

    ↳ nucl-thhep-phnucl-exNPA(2021)·3 citations
29. 29*

    Exploring the Origin of Supermassive Black Holes with Coherent Neutrino Scattering

    Victor Munoz🇪🇸 · Volodymyr Takhistov🇺🇸 · Samuel J. Witte🇪🇸 · George M. Fuller🇺🇸

    Collapsing supermassive stars ($M\gtrsim 3\times 10^4{M}_{\odot }$) at high redshifts can naturally provide seeds and explain the origin of the supermassive black holes observed in the centers of nearly all galaxies. During the collapse of supermassive stars, a burst of non-thermal neutrinos is generated with a luminosity that could greatly exceed that of a conventional core collapse supernova explosion. In this work, we investigate the extent to which the neutrinos produced in these explosions can be observed via coherent elastic neutrino-nucleus scattering (CE$\nu$NS). Large scale direct dark matter detection experiments provide particularly favorable targets. We find that upcoming $\mathcal{O}(100)$ tonne-scale experiments will be sensitive to the collapse of individual supermassive stars at distances as large as $\mathcal{O}(10)$ Mpc.

    ↳ astro-ph.HEhep-exhep-phJCAP(2021)·28 citations
30. 30*

    Strongly Interacting Matter Under Rotation: An Introduction

    Francesco Becattini🇮🇹 · Jinfeng Liao🇺🇸 · Michael Lisa🇺🇸

    Ultrarelativistic collisions between heavy nuclei briefly generate the quark-gluon plasma (QGP), a new state of matter characterized by deconfined partons last seen microseconds after the Big Bang. The properties of the QGP are of intense interest, and a large community has developed over several decades, to produce, measure and understand this primordial plasma. The plasma is now recognized to be a strongly-coupled fluid with remarkable properties, and hydrodynamics is commonly used to quantify and model the system. An important feature of any fluid is its vorticity, related to the local angular momentum density; however, this degree of freedom has received relatively little attention because no experimental signals of vorticity had been detected. Thanks to recent high-statistics datasets from experiments with precision tracking and complete kinemetic coverage at collider energies, hyperon spin polarization measurements have begun to uncover the vorticity of the QGP created at the Relativistic Heavy Ion Collider. The injection of this new degree of freedom into a relatively mature field of research represents an enormous opportunity to generate new insights into the physics of the QGP. The community has responded with enthusiasm, and this book (to be published as a volume of Lecture Notes in Physics series by Springer) represents some of the diverse lines of inquiry into aspects of strongly interacting matter under rotation.

    ↳ nucl-thhep-phLect.Notes Phys.(2021)·27 citations
31. 31*

    Bounds on abundance of primordial black hole and dark matter from EDGES 21-cm signal

    Ashadul Halder🇮🇳 · Shibaji Banerjee🇮🇳

    The redshifted 21cm radio signal has emerged as an important probe for investigating the dynamics of the dark age Universe (recombination to reionization). In the current analysis, we explore the combined effect of primordial black hole (PBH) evaporation and the baryon-dark matter (DM) interaction in the 21cm scenario. The variation of brightness temperature shows remarkable dependence on the DM masses ($m_{\chi }$) and the baryon-DM cross-sections (${\overline{\sigma }}_0$) besides the influences of the PBH parameters (mass ${\mathcal{M}}_{\mathrm{BH}}$ and initial mass fraction ${\beta }_{\mathrm{BH}}$). We address both upper and lower bounds on ${\beta }_{\mathrm{BH}}$ for a wide range of PBH mass in presence of different $m_{\chi }$ and ${\overline{\sigma }}_0$ by incorporating the observational excess $\left(-500_{-500}^{+200}\mathrm{mK}\right)$ of EDGES's experimental results. Finally, we address similar limits in the $m_{\chi }$ - ${\overline{\sigma }}_0$ parameter plane for different PBH masses.

    ↳ astro-ph.COastro-ph.HEhep-phPRD(2021)·35 citations
32. 32*

    An $N/D$ study of the $S_{11}$ channel $\pi N$ scattering amplitude

    Qu-Zhi Li🇨🇳 · Yao Ma🇨🇳 · Wen-Qi Niu🇨🇳 · Yu-Fei Wang🇩🇪 · Han-Qing Zheng🇨🇳

    Extensive dynamical $N/D$ calculations are made in the study of $S_{11}$ channel low energy $\pi$N scatterings, based on various phenomenological model inputs of left cuts at tree level. The subtleties of the singular behavior of the partial wave amplitude at the origin of the complex $s$ plane are carefully analysed. Furthermore, { it is found that the dispersion representation for the phase shift, $\delta$, has to be modified in the case of $\pi$N scatterings. An additional contribution from the dispersion integral exists, which is, however, almost exactly cancelled the contribution from two virtual poles located near the end points of the segment cut induced by $u$ channel nucleon exchanges.} Relying very little on the details of the dynamical inputs, the subthreshold resonance $N^{\ast }(890)$ survives.

    ↳ nucl-thhep-phCPC(2022)·11 citations
33. 33*

    CosmoLattice

    Daniel G. Figueroa🇪🇸 · Adrien Florio🇺🇸 · Francisco Torrenti🇨🇭 · Wessel Valkenburg🇨🇭

    This is the user manual for CosmoLattice, a modern package for lattice simulations of the dynamics of interacting scalar and gauge fields in an expanding universe. CosmoLattice incorporates a series of features that makes it very versatile and powerful: $i)$ it is written in C++ fully exploiting the object oriented programming paradigm, with a modular structure and a clear separation between the physics and the technical details, $ii)$ it is MPI-based and uses a discrete Fourier transform parallelized in multiple spatial dimensions, which makes it specially appropriate for probing scenarios with well-separated scales, running very high resolution simulations, or simply very long ones, $iii)$ it introduces its own symbolic language, defining field variables and operations over them, so that one can introduce differential equations and operators in a manner as close as possible to the continuum, $iv)$ it includes a library of numerical algorithms, ranging from $O(\delta t^2)$ to $O(\delta t^{10})$ methods, suitable for simulating global and gauge theories in an expanding grid, including the case of `self-consistent' expansion sourced by the fields themselves. Relevant observables are provided for each algorithm (e.g.~energy densities, field spectra, lattice snapshots) and we note that remarkably all our algorithms for gauge theories always respect the Gauss constraint to machine precision. In this manual we explain how to obtain and run CosmoLattice in a computer (let it be your laptop, desktop or a cluster). We introduce the general structure of the code and describe in detail the basic files that any user needs to handle. We explain how to implement any model characterized by a scalar potential and a set of scalar fields, either singlets or interacting with $U(1)$ and/or $SU(2)$ gauge fields. CosmoLattice is publicly available at www.cosmolattice.net.

    ↳ astro-ph.COgr-qchep-lathep-phComput.Phys.Commun.(2023)·174 citations
34. 34*

    A Measurement of Stellar Surface Gravity Hidden in Radial Velocity Differences of Co-moving Stars

    Matthew Moschella🇺🇸 · Oren Slone🇺🇸 · Jeff A. Dror🇺🇸 · Matteo Cantiello · Hagai B. Perets

    The gravitational redshift induced by stellar surface gravity is notoriously difficult to measure for non-degenerate stars, since its amplitude is small in comparison with the typical Doppler shift induced by stellar radial velocity. In this study, we make use of the large observational data set of the Gaia mission to achieve a significant reduction of noise caused by these random stellar motions. By measuring the differences in velocities between the components of pairs of co-moving stars and wide binaries, we are able to statistically measure the combined effects of gravitational redshift and convective blueshifting of spectral lines, and nullify the effect of the peculiar motions of the stars. For the subset of stars considered in this study, we find a positive correlation between the observed differences in Gaia radial velocities and the differences in surface gravity and convective blueshift inferred from effective temperature and luminosity measurements. The results rule out a null signal at the $5\sigma$ level for our full data-set. Additionally, we study the sub-dominant effects of binary motion, and possible systematic errors in radial velocity measurements within Gaia. Results from the technique presented in this study are expected to improve significantly with data from the next Gaia data release. Such improvements could be used to constrain the mass-luminosity relation and stellar models which predict the magnitude of convective blueshift.

    ↳ astro-ph.SRastro-ph.GAastro-ph.IMhep-phMNRAS(2022)·5 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.