Tue·Jan 26, 2021Tuesday·January 26, 2021

1. 01*

   Evaluation of the Gottfried sum with use of the truncated moments method

   A. Kotlorz · D. Kotlorz🇵🇱 · O. V. Teryaev🇷🇺

   We reanalyze the experimental NMC data on the nonsinglet structure function $F_2^p-F_2^n$ and E866 data on the nucleon sea asymmetry $\bar{d}/\bar{u}$ using the truncated moments approach elaborated in our previous papers. With help of the special truncated sum one can overcome the problem of the unavoidable experimental restrictions on the Bjorken $x$ and effectively study the fundamental sum rules for the parton distributions and structure functions. Using only the data from the measured region of $x$, we obtain the Gottfried sum ${\int }_0^1{F}_2^{ns}/xdx$ and the integrated nucleon sea asymmetry ${\int }_0^1(\bar{d}-\bar{u})dx$. We compare our results with the reported experimental values and with the predictions obtained for different global parametrizations for the parton distributions. We also discuss the discrepancy between the NMC and E866 results on ${\int }_0^1(\bar{d}-\bar{u})dx$. We demonstrate that this discrepancy can be resolved by taking into account the higher-twist effects.

   hep-phhep-th0 citations
2. 02*

   Renormalization of the flavor-singlet axial-vector current and its anomaly in dimensional regularization

   Taushif Ahmed🇮🇹 · Long Chen🇩🇪 · Michał Czakon🇩🇪

   The renormalization constant $Z_J$ of the flavor-singlet axial-vector current with a non-anticommuting ${\gamma }_5$ in dimensional regularization is determined to order ${\alpha }_s^3$ in QCD with massless quarks. The result is obtained by computing the matrix elements of the operators appearing in the axial-anomaly equation $[{\partial }_{\mu }{J}_5^{\mu }{]}_R=\frac{{\alpha }_s}{4\pi }{n}_f{\mathrm{T}}_F[F\tilde{F}{]}_R$ between the vacuum and a state of two (off-shell) gluons to 4-loop order. Furthermore, through this computation, the conjectured equality between the $\overline{\mathrm{MS}}$ renormalization constant $Z_{F\tilde{F}}$ associated with the operator $[F\tilde{F}{]}_R$ and that of ${\alpha }_s$ is verified explicitly to hold true at 4-loop order. This equality automatically ensures a relation between the respective anomalous dimensions, ${\gamma }_J=\frac{{\alpha }_s}{4\pi }{n}_f{\mathrm{T}}_F{\gamma }_{FJ}$, at order ${\alpha }_s^4$ given the validity of the axial-anomaly equation which was used to determine the non-$\overline{\mathrm{MS}}$ piece of $Z_J$ for the particular ${\gamma }_5$ prescription in use.

   hep-phhep-thJHEP(2021)·30 citations
3. 03*

   Chiral Condensate in Two Dimensional Models

   V.G. Ksenzov🇷🇺

   We investigate two different models. In one of them massive fermions interact with a massive scalar field and in the other the fermion field is in an electrical field (QED2). The chiral condensates are calculated in one-loop approximation. We found that the chiral condensate in the case of the Yukawa interaction the fermions and scalar field does not vanish if the mass of the fermion field tends to zero. The chiral condensate disappears in QED2, if the fermion mass is zero.

   hep-ph0 citations
4. 04*

   Tsallis Statistics in High Energy Physics: Chemical and Thermal Freeze-Outs

   J. Cleymans🇿🇦 · M. W. Paradza🇿🇦

   We present an overview of a proposal in relativistic proton-proton ($pp$) collisions emphasizing the thermal or kinetic freeze-out stage in the framework of the Tsallis distribution. In this paper we take into account the chemical potential present in the Tsallis distribution by following a two step procedure. In the first step we used the redundancy present in the variables such as the system temperature, $T$, volume, $V$, Tsallis exponent, $q$, chemical potential, $\mu$, and performed all fits by effectively setting to zero the chemical potential. In the second step the value $q$ is kept fixed at the value determined in the first step. This way the complete set of variables $T,q,V$ and $\mu$ can be determined. The final results show a weak energy dependence in $pp$ collisions at the centre-of-mass energy $\sqrt{s}=6$ GeV to 13 TeV. The chemical potential $\mu$ at kinetic freeze-out shows an increase with beam energy. This simplifies the description of the thermal freeze-out stage in $pp$ collisions as the values of $T$ and of the freeze-out radius $R$ vary only mildly over a wide range of beam energies.

   hep-phMDPI Physics(2020)·28 citations
5. 05*

   Chirality imbalance and chiral magnetic effect under a parallel electromagnetic field

   Hayato Aoi🇯🇵 · Katsuhiko Suzuki🇯🇵

   We study the time evolution of the chirality imbalance $n_5$ and the chiral magnetic effect (CME) under the external parallel electromagnetic fields without assuming the artificial chiral asymmetric source. We adopt the time-dependent Sauter-type electric and constant magnetic field, and obtain analytical solutions of the Dirac equation for a massive fermion. We use the point-split regularization to calculate the vacuum contribution in the gauge invariant way. As a result, we find that $n_5$ and CME current increase substantially as the electric field increases, and stay finite after the electric field is switched off. The chirality imbalance and CME current are shown to consist of a dominant contribution, which is essentially proportional to relativistic velocity, and a small oscillating part. We find a simple analytical relation between $n_5$ and the fermion pair-production rate from the vacuum. We also discuss dynamical origin of the chirality imbalance in detail.

   hep-phnucl-thPRD(2021)·5 citations
6. 06*

   Strong-interaction matter under extreme conditions from chiral quark models with nonlocal separable interactions

   D. Gomez Dumm🇦🇷 · J.P. Carlomagno🇦🇷 · N.N. Scoccola🇦🇷

   We review the current status of the research on effective nonlocal NJL-like chiral quark models with separable interactions, focusing on the application of this approach to the description of the properties of hadronic and quark matter under extreme conditions. The analysis includes the predictions for various hadron properties in vacuum, as well as the study of the features of deconfinement and chiral restoration phase transitions for systems at finite temperature and/or density. We also address other related subjects, such as the study of phase transitions for imaginary chemical potentials, the possible existence of inhomogeneous phase regions, the presence of color superconductivity, the effects produced by strong external magnetic fields, and the application to the description of compact stellar objects.

   hep-phSymmetry(2021)·19 citations
7. 07*

   The Weak Eightfold Way: $SU(3{)}_W$ unification of the electroweak interactions

   P. Q. Hung🇺🇸

   In a recent work, a successful prediction has been made for ${\sin }^2{\theta }_W$ at an energy scale of O(TeV) based on the Dirac quantization condition of an electroweak monopole of the EW-${\nu }_R$ model. The fact that such a prediction can be made has prompted the following question: Can $SU(2)$ be unified with $U(1)$ at O(TeV) scale since a prediction for ${\sin }^2{\theta }_W$ necessarily relates the $U(1)$ coupling $g^{\prime }$ to the $SU(2)$ weak coupling $g$? It is shown in this manuscript that this can be accomplished by embedding $SU(2)\times U(1)$ into $SU(3{)}_W$ (The Weak Eightfold Way) with the following results: 1) The same prediction of the weak mixing angle is obtained; 2) The scalar representations of $SU(3{)}_W$ contain all those that are needed to build the the EW-${\nu }_R$ model and, in particular, the real Higgs triplet used in the construction of the electroweak monopole. 3) Anomaly freedom requires the existence of mirror fermions present in the EW-${\nu }_R$ model. 4) Vector-Like Quarks (VLQ) with unconventional electric charges are needed to complete the $SU(3{)}_W$ representations containing the right-handed up-quarks, with interesting experimental implications such as the prediction of doubly-charged hybrid mesons.

   hep-ph0 citations
8. 08*

   Novel pentaquark picture for singly heavy baryons from chiral symmetry

   Daiki Suenaga🇯🇵 · Atsushi Hosaka🇯🇵

   We propose a new type of structure for singly heavy baryons of $Qqq\bar{q}q$ in addition to the conventional one of $Qqq$. Based on chiral symmetry of the light quarks, we show that the $Qqq\bar{q}q$ baryon offers a novel picture for heavy quark spin-singlet and flavor-antisymmetric baryons. By making use of the effective Lagrangian approach, we find ${\Lambda }_c(2765)$ and ${\Xi }_c(2967)$ are mostly $Qqq\bar{q}q$ while ${\Lambda }_c(2286)$ and ${\Xi }_c(2470)$ are mostly $Qqq$. The masses of negative-parity baryons are predicted. We also derive a sum rule and the extended Goldberger-Treiman relation that the masses of the baryons satisfy. Furthermore, a mass degeneracy of parity partners of the baryons with the restoration of chiral symmetry is discussed. These are the unique features that the conventional picture of radial excitation in the quark model does not accommodate. Our findings provide useful information not only for future experiments but also for future lattice simulations on diquarks.

   hep-phnucl-thPRD(2021)·22 citations
9. 09*

   Production of $D$-wave states of $\bar{b}c$ quarkonium at the LHC

   A.V. Berezhnoy🇷🇺 · I.N. Belov🇷🇺 · A.K. Likhoded🇷🇺

   The hadronic production of $D$-wave states of $\bar{b}c$ is studied. The relative yield of such states is estimated for kinematic conditions of LHC experiments.

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

    Transport properties in magnetized compact stars

    Toshitaka Tatsumi🇯🇵 · Hiroaki Abuki🇯🇵

    Transport properties of dense quark matter are discussed in the strong magnetic field, B. B dependence as well as density dependence of the Hall conductivity is discussed in the inhomogeneous chiral phase. Anomalous Hall effect is intrinsic to the inhomogeneous chiral phase and resembles the one in Weyl semimetals in condensed matter physics. Some theoretical aspects inherent in anomalous Hall effect are revealed.

    hep-phastro-ph.HEParticles(2021)·0 citations
11. 11*

    Possible experimental signatures of stable double beauty tetraquarks

    Alexey Drutskoy🇷🇺

    A new method is proposed to search for the double beauty tetraquark $bb\bar{u}\bar{d}$ with a mass below the $BB$ threshold. The $b\bar{d}-\bar{b}d$ mixing can result in evolution of the tetraquark content to $b\bar{b}\bar{u}d$ with the following strong decay into the ${\rm Y}$(1S)${\pi }^{-}$ and ${\rm Y}$(2S)${\pi }^{-}$ final states in a secondary vertex displaced from the primary $pp$ collision vertex. This experimental signature is clean, has a high selection efficiency and can be well separated from backgrounds. Experimental signatures for searches for other double heavy tetraquarks are also discussed, suggesting the possibility of the $b\bar{d}$ or $b\bar{s}$ mixing.

    hep-ph2 citations
12. 12*

    The light front wave functions and diffractive electroproduction of vector mesons

    Chao Shi🇨🇳 · Ya-Ping Xie🇨🇳 · Ming Li🇨🇳 · Xurong Chen🇨🇳 · Hong-Shi Zong🇨🇳

    We determine the leading Fock-state light front wave functions (LF-LFWFs) of the $\rho$ and J/$\psi$ mesons, for the first time from the Dyson-Schwinger and Bethe-Salpeter equations (DS-BSEs) approach. A unique advantage of this method is that it renders a direct extraction of LF-LFWFs in presence of a number of higher Fock-states. Modulated by the current quark mass and driven by the dynamical chiral symmetry breaking (DCSB), we find the $\rho$ and $J/\psi$ LF-LFWFs different in profile, i.e., the former are broadly distributed in $x$ (the longitudinal light-cone momentum fraction of meson carried by quark) while the latter are narrow. Moreover, the $\rho$ LF-LFWFs contribute less than 50% to the total Fock-state normalization, suggesting considerable higher Fock-states in $\rho$. We then use these LF-LFWFs to study the diffractive $\rho$ and $J/\psi$ electroproduction within the dipole picture. The calculated cross section shows general agreement with HEAR data, except for growing discrepancy in $\rho$ production at low photon virtuality. Our work provides a first dipole picture analysis on diffractive $\rho$ electroproduction that confronts the parton nature of the light (anti)quarks.

    hep-phPRD(2021)·16 citations
13. 13*

    Application of the Uniformized Mittag-Leffler Expansion to $\Lambda (1405)$

    Wren Yamada🇯🇵 · Osamu Morimatsu🇯🇵

    We study the pole properties of $\Lambda (1405)$ in a model-independent manner by applying the Uniformized Mittag-Leffler expansion proposed in our previous paper. The resonant energy, width and residues are determined by expanding the observable as a sum of resonant-pole pairs under an appropriate parameterization which expresses the observable to be single-valued, and fitting it to experimental data of the invariant-mass distribution of ${\pi }^{+}{\Sigma }^{-}$, ${\pi }^{-}{\Sigma }^{+}$, ${\pi }^0{\Sigma }^0$ final states in the reaction, $\gamma p\to K^{+}\pi \Sigma$, and the elastic and inelastic cross section, $K^{-}p\to K^{-}p$, ${\bar{K}}^{0}n$, ${\pi }^{+}{\Sigma }^{-}$, ${\pi }^{-}{\Sigma }^{+}$. As we gradually increase the number of pairs from one to three, the first pair converges while the second and third pairs emerge further and further away from the first pair, implying that the Uniformized Mittag-Leffler expansion with three pairs is almost convergent in the vicinity of the $\Lambda (1405)$. The broad peak structure between the $\pi \Sigma$ and $\bar{K}N$ thresholds regarded to be $\Lambda (1405)$ is explained by a single pair with a resonant energy of 1420 $\pm$ 1 MeV, and a half width of 48 $\pm$ 2 MeV, which is consistent with the single-pole picture of $\Lambda (1405)$. We conclude that the Uniformized Mittag-Leffler expansion turns out to be a very powerful method to obtain resonance energy, width and residues from the near-threshold spectrum.

    hep-phhep-exnucl-thPRC(2021)·13 citations
14. 14*

    Navigating the pitfalls of relic neutrino detection

    Yevheniia Cheipesh🇳🇱 · Vadim Cheianov🇳🇱 · Alexey Boyarsky🇳🇱

    Beta-spectrum of radioactive atoms was long ago predicted to bear an imprint of the Cosmic Neutrino Background (C$\nu$B). Over the years, it has been recognised that the best chance of achieving the signal-to-noise ratio required for the observation of this effect lies with solid-state designs. Here we bring to the fore a fundamental quantum limitation on the type of beta-decayer that can be used in such a design. We derive a simple usability criterion and show that ${}^3\mathrm{H}$, which is the most popular choice, fails to meet it. We provide a list of potentially suitable isotopes and discuss why their use in C$\nu$B detection requires further research.

    hep-phcond-mat.mes-hallPRD(2021)·55 citations
15. 15*

    Mott dissociation and kaon to pion ratio in the EPNJL model

    D. Blaschke🇷🇺 · A. V. Friesen🇷🇺 · Yu. L. Kalinovsky🇷🇺 · A. E. Radzhabov🇷🇺

    The behaviour of pseudoscalar mesons within the SU(3)PNJL-like models is considered for finite T and ${\mu }_B$. We compare the pole approximation (Breit-Wigner) with the Beth-Uhlenbeck approach. We evaluate the $K/\pi$ ratios along the phase transition line in the T-${\mu }_B$ plane with constant and $T/{\mu }_B$-dependent pion and strange quark chemical potentials. Using the model, we can show that the splitting of kaon and anti-kaon masses appears as a result of introduction of density and this explains the difference in the $K^{+}/{\pi }^{+}$ ratio and $K^{-}/{\pi }^{-}$ ratio at low $\sqrt{s_{NN}}$ and their tendency to the same value at high $\sqrt{s_{NN}}$. A sharp "horn" effect in the $K^{+}/{\pi }^{+}$ ratio is explained by the enhanced pion production which can be described by occurrence of a nonequilibrium pion chemical potential of the order of the pion mass. We elucidate that the horn effect is not related to the existence of a critical endpoint in the QCD phase diagram.

    hep-phPhys.Part.Nucl.(2021)·1 citation
16. 16*

    New Physics Constraints from Atomic Parity Violation in ${}^{133}$Cs

    B. K. Sahoo🇮🇳 · B. P. Das🇯🇵 · H. Spiesberger🇩🇪

    Our improved calculation of the nuclear spin-independent parity violating electric dipole transition amplitude ($E{1}_{PV}$) for $6s{}^2{S}_{1/2}-7s{}^2{S}_{1/2}$ in ${}^{133}$Cs in combination with the most accurate (0.3\%) measurement of this quantity yields a new value for the nuclear weak charge $Q_W=-73.71(26{)}_{ex}(23{)}_{th}$ against the Standard Model (SM) prediction $Q_W^{\text{SM}}=-73.23(1)$. The advances in our calculation of $E{1}_{PV}$ have been achieved by using a variant of the perturbed relativistic coupled-cluster theory which treats the contributions of the core, valence and excited states to $E{1}_{PV}$ on the same footing unlike the previous high precision calculations. Furthermore, this approach resolves the controversy regarding the sign of the core correlation effects. We discuss the implications of the deviation of our result for $Q_W$ from the SM value by considering different scenarios of new physics.

    hep-phphysics.atom-phPRD(2021)·39 citations
17. 17*

    Double-strangeness production in $\Lambda p\to K^{+}X$ reaction

    Jung Keun Ahn🇰🇷 · Seung-il Nam🇰🇷

    We investigate $S=-2$ production from the $\Lambda p\to K^{+}X$ reactions within the effective Lagrangian approach. The $\Lambda p\to K^{+}\Lambda \Lambda$ and $\Lambda p\to K^{+}{\Xi }^{-}p$ reactions are considered to find the lightest $S=-2$ system, which is $H$-dibaryon. We assume that the $H(2250)\to \Lambda \Lambda$, and $H(2270)\to {\Xi }^{-}p$ decays with the intrinsic decay width of 1 MeV. According to our calculations, the total cross-sections for $\Lambda p\to K^{+}\Lambda \Lambda$ and $\Lambda p\to K^{+}{\Xi }^{-}p$ reactions were found to be of the order of a few $\mu$b in the $\Lambda$ beam momentum range of up to 5 GeV$/c$. Furthermore, the direct access of information regarding the interference patterns between the $H$-dibaryon and non-resonant contributions was demonstrated.

    hep-phhep-exnucl-exnucl-thPRD(2021)·8 citations
18. 18*

    Scalar Multiplet Dark Matter in a Fast Expanding Universe: resurrection of the desert region

    Basabendu Barman🇮🇳 · Purusottam Ghosh🇮🇳 · Farinaldo S. Queiroz🇧🇷 · Abhijit Kumar Saha🇮🇳

    We examine the impact of a faster expanding Universe on the phenomenology of scalar dark matter (DM) associated with $SU(2{)}_L$ multiplets. Earlier works with radiation dominated Universe have reported the presence of desert region for both inert $SU(2{)}_L$ doublet and triplet DM candidates where the DM is under abundant. We find that the existence of a faster expanding component before BBN can revive a substantial part of the desert parameter space consistent with relic density requirements and other direct and indirect search bounds. We also review the possible collider search prospects of the newly obtained parameter space and predict that such region might be probed at the future colliders with improved sensitivity via a disappearing/stable charged track.

    hep-phastro-ph.HEPRD(2021)·24 citations
19. 19*

    CASCADE3 A Monte Carlo event generator based on TMDs

    S. Baranov🇷🇺 · A. Bermudez Martinez🇩🇪 · L.I. Estevez Banos🇩🇪 · F. Guzman🇨🇺 · F. Hautmann🇧🇪 · H. Jung🇩🇪 · A. Lelek🇧🇪 · J. Lidrych🇩🇪 · A. Lipatov🇷🇺 · M. Malyshev🇷🇺 · M. Mendizabal🇩🇪 · S. Taheri Monfared🇩🇪 and 3 other authors

    The CASCADE3 Monte Carlo event generator based on Transverse Momentum Dependent (TMD) parton densities is described. Hard processes which are generated in collinear factorization with LO multileg or NLO parton level generators are extended by adding transverse momenta to the initial partons according to TMD densities and applying dedicated TMD parton showers and hadronization. Processes with off-shell kinematics within $k_t$-factorization, either internally implemented or from external packages via LHE files, can be processed for parton showering and hadronization. The initial state parton shower is tied to the TMD parton distribution, with all parameters fixed by the TMD distribution.

    hep-phnucl-thEPJC(2021)·114 citations
20. 20*

    Strong $B_{Q{Q}^{\prime }}^{\ast }{B}_{Q{Q}^{\prime }}V$ vertices and the radiative decays of $B_{QQ}^{\ast }\to B_{QQ}\gamma$ in the light-cone sum rules

    T. M. Aliev🇹🇷 · T. Barakat🇸🇦 · K. Şimşek🇺🇸

    The strong coupling constants of spin-3/2 to spin-1/2 doubly heavy baryon transitions with light vector mesons are estimated within the light-cone QCD sum rules method. Moreover, using the vector-meson dominance ansätz, the widths of radiative decays $B_{QQ}^{\ast }\to B_{QQ}\gamma$ are calculated. The results for the said decay widths are compared to the predictions of other approaches.

    hep-phEPJA(2021)·15 citations
21. 21*

    Extraction of the multiplicity dependence of Multiparton Interactions from LHC pp data using Machine Learning techniques

    Antonio Ortiz🇲🇽 · Erik Zepeda🇲🇽

    Over the last years, Machine Learning (ML) methods have been successfully applied to a wealth of problems in high-energy physics. For instance, in a previous work we have reported that using ML techniques one can extract the Multiparton Interactions (MPI) activity from minimum-bias pp data. Using the available LHC data on transverse momentum spectra as a function of multiplicity, we reported the average number of MPI ($⟨N_{\mathrm{mpi}}⟩$) for minimum-bias pp collisions at $\sqrt{s}=5.02$ and 13\,TeV. In this work, we apply the same analysis to a new set of data. We report that $⟨N_{\mathrm{mpi}}⟩$ amounts to $3.98\pm 1.01$ for minimum-bias pp collisions at $\sqrt{s}=7$\,TeV. These complementary results suggest a modest center-of-mass energy dependence of $⟨N_{\mathrm{mpi}}⟩$. The study is further extended aimed at extracting the multiplicity dependence of $⟨N_{\mathrm{mpi}}⟩$ for the three center-of-mass energies. We show that our results qualitatively agree with existing ALICE measurements sensitive to MPI. Namely, $⟨N_{\mathrm{mpi}}⟩$ increases approximately linearly with the charged-particle multiplicity. But, it deviates from the linear dependence at large charged-particle multiplicities. The deviation from the linear trend can be explained in terms of a bias towards harder processes given the multiplicity selection at mid-pseudorapidity. The results reported in this paper provide additional evidence of the presence of MPI in pp collisions, and they can be useful for a better understanding of the heavy-ion-like behaviour observed in pp data.

    hep-phJ.Phys.G(2021)·14 citations
22. 22*

    Breakdown of chiral perturbation theory for the axion hot dark matter bound

    Luca Di Luzio🇩🇪 · Guido Martinelli🇮🇹 · Gioacchino Piazza🇫🇷

    We show that the commonly adopted hot dark matter (HDM) bound on the axion mass $m_a\lesssim$ 1 eV is not reliable, since it is obtained by extrapolating the chiral expansion in a region where the effective field theory breaks down. This is explicitly shown via the calculation of the axion-pion thermalization rate at the next-to-leading order in chiral perturbation theory. We finally advocate a strategy for a sound extraction of the axion HDM bound via lattice QCD techniques.

    hep-phastro-ph.COhep-latPRL(2021)·57 citations
23. 23*

    A No-Lose Theorem for Discovering the New Physics of $(g-2{)}_{\mu }$ at Muon Colliders

    Rodolfo Capdevilla🇨🇦 · David Curtin🇨🇦 · Yonatan Kahn🇺🇸 · Gordan Krnjaic🇺🇸

    We perform a model-exhaustive analysis of all possible beyond Standard Model (BSM) solutions to the $(g-2{)}_{\mu }$ anomaly to study production of the associated new states at future muon colliders, and formulate a no-lose theorem for the discovery of new physics if the anomaly is confirmed and weakly coupled solutions below the GeV scale are excluded. Our goal is to find the highest possible mass scale of new physics subject only to perturbative unitarity, and optionally the requirements of minimum flavour violation (MFV) and/or naturalness. We prove that a 3 TeV muon collider is guaranteed to discover all BSM scenarios in which $\Delta a_{\mu }$ is generated by SM singlets with masses above $\sim$ GeV; lighter singlets will be discovered by upcoming low-energy experiments. If new states with electroweak quantum numbers contribute to $(g-2{)}_{\mu }$, the minimal requirements of perturbative unitarity guarantee new charged states below $\mathcal{O}(100\mathrm{TeV})$, but this is strongly disfavoured by stringent constraints on charged lepton flavour violating (CLFV) decays. Reasonable BSM theories that satisfy CLFV bounds by obeying Minimal Flavour Violation (MFV) and avoid generating two new hierarchy problems require the existence of at least one new charged state below $\sim 10$ TeV. This strongly motivates the construction of high-energy muon colliders, which are guaranteed to discover new physics: either by producing these new charged states directly, or by setting a strong lower bound on their mass, which would empirically prove that the universe is fine-tuned and violates the assumptions of MFV while somehow not generating large CLFVs. The former case is obviously the desired outcome, but the latter scenario would perhaps teach us even more about the universe by profoundly revising our understanding of naturalness, cosmological vacuum selection, and the SM flavour puzzle.

    hep-phhep-exPRD(2022)·129 citations
24. 24*

    Detecting Dark Matter with Far-Forward Emulsion and Liquid Argon Detectors at the LHC

    Brian Batell🇺🇸 · Jonathan L. Feng🇺🇸 · Sebastian Trojanowski🇵🇱

    New light particles may be produced in large numbers in the far-forward region at the LHC and then decay to dark matter, which can be detected through its scattering in far-forward experiments. We consider the example of invisibly-decaying dark photons, which decay to dark matter through $A^{\prime }\to \chi \chi$. The dark matter may then be detected through its scattering off electrons $\chi e^{-}\to \chi e^{-}$. We consider the discovery potential of detectors placed on the beam collision axis 480 m from the ATLAS interaction point, including an emulsion detector (FASER$\nu$2) and, for the first time, a Forward Liquid Argon Experiment (FLArE). For each of these detector technologies, we devise cuts that effectively separate the single $e^{-}$ signal from the leading neutrino- and muon-induced backgrounds. We find that 10- to 100-tonne detectors may detect hundreds to thousands of dark matter events in the HL-LHC era and will sensitively probe the thermal relic region of parameter space. These results motivate the construction of far-forward emulsion and liquid argon detectors at the LHC, as well as a suitable location to accommodate them, such as the proposed Forward Physics Facility.

    hep-phhep-exPRD(2021)·89 citations
25. 25*

    Development of a web application for monitoring solar activity and cosmic radiation

    David Pelosi🇮🇹 · Nicola Tomassetti🇮🇹 · Matteo Duranti🇮🇹

    The flux of cosmic rays (CRs) in the heliosphere is subjected to remarkable time variations caused by the 11-year cycle of solar activity. To help the study of this effect, we have developed a web application (Heliophysics Virtual Observatory) that collects real-time data on solar activity, interplanetary plasma, and charged radiation from several space missions or observatories. As we will show, our application can be used to visualize, manipulate, and download updated data on sunspots, heliospheric magnetic fields, solar wind, and neutron monitors counting rates. Data and calculations are automatically updated on daily basis. A nowcasting for the energy spectrum of CR protons near-Earth is also provided using calculations and real-time neutron monitor data as input.

    ↳ physics.space-phastro-ph.SRhep-phphysics.pop-phNuovo Cim.C(2021)·0 citations
26. 26*

    Signature of Lorentz Violation in Continuous Gravitational-Wave Spectra of Ellipsoidal Neutron Stars

    Rui Xu🇨🇳 · Yong Gao🇨🇳 · Lijing Shao🇨🇳

    We study effects of Lorentz-invariance violation on the rotation of neutron stars (NSs) in the minimal gravitational Standard-Model Extension framework, and calculate the quadrupole radiation generated by them. Aiming at testing Lorentz invariance with observations of continuous gravitational waves (GWs) from rotating NSs in the future, we compare the GW spectra of a rotating ellipsoidal NS under Lorentz-violating gravity with those of a Lorentz-invariant one. The former are found to possess frequency components higher than the second harmonic, which does not happen for the latter, indicating those higher frequency components to be potential signatures of Lorentz violation in continuous GW spectra of rotating NSs.

    ↳ gr-qcastro-ph.HEhep-phGalaxies(2021)·13 citations
27. 27*

    Oscillations of sterile neutrinos from dark matter decay eliminates the IceCube-Fermi tension

    Luis A. Anchordoqui🇺🇸 · Vernon Barger🇺🇸 · Danny Marfatia🇺🇸 · Mary Hall Reno🇺🇸 · Thomas J. Weiler🇺🇸

    IceCube has observed a flux of cosmic neutrinos, with a "bump" in the energy range $10\lesssim E/\mathrm{TeV}\lesssim 100$ that creates a $3\sigma$ tension with gamma-ray data from the Fermi satellite. This has been interpreted as evidence for a population of hidden cosmic-ray accelerators. We propose an alternative explanation of this conundrum on the basis of cold dark matter which decays into sterile neutrinos that after oscillations produce the bump in the cosmic neutrino spectrum.

    ↳ astro-ph.HEhep-exhep-phPRD(2021)·8 citations
28. 28*

    Anomalous dimensions at large charge in d=4 O(N) theory

    I. Jack🇬🇧 · D.R.T Jones🇬🇧

    Recently it was shown that the scaling dimension of the operator ${\varphi }^n$ in $\lambda ({\varphi }^{\ast }\varphi {)}^2$ theory may be computed semi-classically at the Wilson-Fisher fixed point in $d=4-ϵ$, for generic values of $\lambda n$ and this was verified to two loop order in perturbation theory at leading and sub-leading $n$. In subsequent work, this result was generalised to operators of fixed charge $Q$ in $O(N)$ theory and verified up to three loops in perturbation theory at leading and sub-leading order. Here we extend this verification to four loops in $O(N)$ theory, once again at leading and sub-leading order. We also investigate the strong-coupling regime.

    ↳ hep-thhep-phPRD(2021)·28 citations
29. 29*

    Electromagnetic fields from the extended Kharzeev-McLerran-Warringa model in relativistic heavy-ion collisions

    Yi Chen🇨🇳 · Xin-Li Sheng🇨🇳 · Guo-Liang Ma🇨🇳

    Based on the Kharzeev-McLerran-Warringa (KMW) model that estimates strong electromagnetic (EM) fields generated in relativistic heavy-ion collisions, we generalize the formulas of EM fields in the vacuum by incorporating the longitudinal position dependence, the generalized charge distributions and retardation correction. We further generalize the formulas of EM fields in the pure quark-gluon plasma (QGP) medium by incorporating a constant Ohm electric conductivity and also during the realistic early-time stages QGP evolution by using a time-dependent electric conductivity. Using the extended KMW model, we observe a slower time evolution and a more reasonable impact parameter $b$ dependence of the magnetic field strength than those from the original KMW model in the vacuum. The inclusion of medium effects by using the lattice data helps to further prolong the time evolution of magnetic field, such that the magnetic field strength during the realistic QGP evolution at thermal freeze-out time can meet the $1\sigma$ bound constrained from experimentally measured difference in global polarizations of $\Lambda$ and $\bar{\Lambda }$ hyperons in Au+Au collisions at top RHIC energy. These generalized formulations in the extended KMW model will be potentially useful for many EM fields relevant studies in heavy-ion collisions, especially at lower colliding energies and for various species of colliding nuclei.

    ↳ nucl-thhep-phnucl-exNPA(2021)·27 citations
30. 30*

    Correlation between initial spatial anisotropy and final momentum anisotropies in relativistic heavy ion collisions

    Sanchari Thakur🇮🇳 · Sumit Kumar Saha🇮🇳 · Pingal Dasgupta🇨🇳 · Rupa Chatterjee🇮🇳 · Subhasis Chattopadhyay🇮🇳

    The particle momentum anisotropy ($v_n$) produced in relativistic nuclear collisions is considered to be a response of the initial geometry or the spatial anisotropy ${ϵ}_n$ of the system formed in these collisions. The linear correlation between ${ϵ}_n$ and $v_n$ quantifies the efficiency at which the initial spatial eccentricity is converted to final momentum anisotropy in heavy ion collisions. We study the transverse momentum, collision centrality, and beam energy dependence of this correlation for different charged particles using a hydrodynamical model framework. The (${ϵ}_n-v_n$) correlation is found to be stronger for central collisions and also for n=2 compared to that for n=3 as expected. However, the transverse momentum ($p_T$) dependent correlation coefficient shows interesting features which strongly depends on the mass as well as $p_T$ of the emitted particle. The correlation strength is found to be larger for lighter particles in the lower $p_T$ region. We see that the relative fluctuation in anisotropic flow depends strongly in the value of $\eta /s$ specially in the region $p_T<1$ GeV unlike the correlation coefficient which does not show significant dependence on $\eta /s$.

    ↳ nucl-thhep-phNPA(2021)·5 citations
31. 31*

    Hydrodynamic fluctuations and long-time tails in a fluid on an anisotropic background

    Ashish Shukla🇨🇦

    The effective low-energy late-time description of many body systems near thermal equilibrium provided by classical hydrodynamics in terms of dissipative transport phenomena receives important corrections once the effects of stochastic fluctuations are taken into account. One such physical effect is the occurrence of long-time power law tails in correlation functions of conserved currents. In the hydrodynamic regime $\vec{k}\to 0$ this amounts to non-analytic dependence of the correlation functions on the frequency $\omega$. In this article, we consider a relativistic fluid with a conserved global $U(1)$ charge in the presence of a strong background magnetic field, and compute the long-time tails in correlation functions of the stress tensor. The presence of the magnetic field renders the system anisotropic. In the absence of the magnetic field, there are three out-of-equilibrium transport parameters that arise at the first order in the hydrodynamic derivative expansion, all of which are dissipative. In the presence of a background magnetic field, there are ten independent out-of-equilibrium transport parameters at the first order, three of which are non-dissipative and the rest are dissipative. We provide the most general linearized equations about a given state of thermal equilibrium involving the various transport parameters in the presence of a magnetic field, and use them to compute the long-time tails for the fluid.

    ↳ hep-thcond-mat.str-elhep-phnucl-th+1NPB(2021)·6 citations
32. 32*

    Critical exponents from five-loop scalar theory renormalization near six-dimensions

    Mikhail Kompaniets🇷🇺 · Andrey Pikelner🇷🇺

    We present five-loop results for the renormalization of various models with a cubic interaction (in $d=6-2\epsilon$ dimensions). For the scalar model and its $O(n)$-symmetric extension we provide renormalization constants, anomalous dimensions and critical exponents. We discuss in detail the method of calculation, and provide all counterterms up to five loops. This allows one to consider generalizations of the ${\phi }^3$ theory to other symmetries.

    ↳ hep-thcond-mat.stat-mechhep-phPLB(2021)·34 citations
33. 33*

    A Trailhead for Quantum Simulation of SU(3) Yang-Mills Lattice Gauge Theory in the Local Multiplet Basis

    Anthony Ciavarella🇺🇸 · Natalie Klco🇺🇸 · Martin J. Savage🇺🇸

    Maintaining local interactions in the quantum simulation of gauge field theories relegates most states in the Hilbert space to be unphysical -- theoretically benign, but experimentally difficult to avoid. Reformulations of the gauge fields can modify the ratio of physical to gauge-variant states often through classically preprocessing the Hilbert space and modifying the representation of the field on qubit degrees of freedom. This paper considers the implications of representing SU(3) Yang-Mills gauge theory on a lattice of irreducible representations in both a global basis of projected global quantum numbers and a local basis in which controlled-plaquette operators support efficient time evolution. Classically integrating over the internal gauge space at each vertex (e.g., color isospin and color hypercharge) significantly reduces both the qubit requirements and the dimensionality of the unphysical Hilbert space. Initiating tuning procedures that may inform future calculations at scale, the time evolution of one- and two-plaquettes are implemented on one of IBM's superconducting quantum devices, and early benchmark quantities are identified. The potential advantages of qudit environments, with either constrained 2D hexagonal or 1D nearest-neighbor internal state connectivity, are discussed for future large-scale calculations.

    ↳ quant-phhep-lathep-phnucl-thPRD(2021)·288 citations
34. 34*

    Decay amplitudes to three hadrons from finite-volume matrix elements

    Maxwell T. Hansen🇬🇧 · Fernando Romero-López🇪🇸 · Stephen R. Sharpe🇺🇸

    We derive relations between finite-volume matrix elements and infinite-volume decay amplitudes, for processes with three spinless, degenerate and either identical or non-identical particles in the final state. This generalizes the Lellouch-Lüscher relation for two-particle decays and provides a strategy for extracting three-hadron decay amplitudes using lattice QCD. Unlike for two particles, even in the simplest approximation, one must solve integral equations to obtain the physical decay amplitude, a consequence of the nontrivial finite-state interactions. We first derive the result in a simplified theory with three identical particles, and then present the generalizations needed to study phenomenologically relevant three-pion decays. The specific processes we discuss are the CP-violating $K\to 3\pi$ weak decay, the isospin-breaking $\eta \to 3\pi$ QCD transition, and the electromagnetic ${\gamma }^{\ast }\to 3\pi$ amplitudes that enter the calculation of the hadronic vacuum polarization contribution to muonic $g-2$.

    ↳ hep-lathep-phJHEP(2021)·67 citations
35. 35*

    Probing $\mu$eV ALPs with future LHAASO observation of AGN $\gamma$-ray spectra

    Guangbo Long🇨🇳 · Siyu Chen🇨🇳 · Shuo Xu🇨🇳 · Hong-Hao Zhang🇨🇳

    Axion-like particles (ALPs) are predicted in some well-motivated theories beyond the Standard Model. The TeV gamma-rays from active galactic nuclei (AGN) suffer attenuation by the pair production interactions with the cosmic background light (EBL/CMB) during its travel to the earth. The attenuation can be circumvented through photon-ALP conversions in the AGN and Galaxy magnetic-field, and a flux enhancement is expected to arise in the observed spectrum. In this work, we study the potential of the AGN gamma-ray spectrum for energy up to above 100\,TeV to probe ALP-parameter space at around $\mu$eV, where the coupling $g_{a\gamma }$ is so far relatively weakly constrained. We find the nearby and bright sources, Mrk\,501, IC\,310 and M\,87, are suitable for our objective. Assuming an intrinsic spectrum exponential cutoff energy, we extrapolate the observed spectra of these sources up to above 100\,TeV by the models with/without ALPs. For $g_{a\gamma }\gtrsim 2\times$$10^{-11}\mathrm{Ge}{\mathrm{V}}^{-1}$ with $m_a\lesssim 0.5\mu$eV, the flux at around 100\,TeV predicted by the ALP model can be enhanced more than an order of magnitude than that from the standard absorption, and could be detected by LHAASO. Our result is subject to the uncertainty from the intrinsic cutoff energy and the AGN lobe (or plume) magnetic-field. For an optimistic estimation, the constraint can be improved to $g_{a\gamma }\gtrsim 2\times$$10^{-11}\mathrm{Ge}{\mathrm{V}}^{-1}$ with $m_a\lesssim 1\mu$eV. This require further observations on these sources by the forthcoming CTA, LHAASO, SWGO and so on.

    ↳ astro-ph.HEastro-ph.COhep-phPRD(2021)·18 citations
36. 36*

    Extracting Dark-Matter Velocities from Halo Masses: A Reconstruction Conjecture

    Keith R. Dienes🇺🇸 · Fei Huang🇨🇳 · Jeff Kost🇬🇧 · Kevin Manogue🇺🇸 · Brooks Thomas🇺🇸

    Increasing attention has recently focused on non-traditional dark-matter production mechanisms which result in primordial dark-matter velocity distributions with highly non-thermal shapes. In this paper, we undertake an assessment of how the detailed shape of a general dark-matter velocity distribution impacts structure formation in the non-linear regime. In particular, we investigate the impact on the halo-mass and subhalo-mass functions, as well as on astrophysical observables such as satellite and cluster-number counts. We find that many of the standard expectations no longer hold in situations in which this velocity distribution takes a highly non-trivial, even multi-modal shape. For example, we find that the nominal free-streaming scale alone becomes insufficient to characterize the effect of free-streaming on structure formation. In addition, we propose a simple one-line conjecture which can be used to "reconstruct" the primordial dark-matter velocity distribution directly from the shape of the halo-mass function. Although our conjecture is completely heuristic, we show that it successfully reproduces the salient features of the underlying dark-matter velocity distribution even for non-trivial distributions which are highly non-thermal and/or multi-modal, such as might occur for non-minimal dark sectors. Moreover, since our approach relies only on the halo-mass function, our conjecture provides a method of probing dark-matter properties even for scenarios in which the dark and visible sectors interact only gravitationally.

    ↳ astro-ph.COhep-phPRD(2022)·13 citations
37. 37*

    Extreme-Value Distributions and Primordial Black-Hole Formation

    Florian Kuhnel🇩🇪 · Dominik J. Schwarz🇩🇪

    We argue that primordial black-hole formation must be described by means of extreme-value theory. This is a consequence of the large values of the energy density required to initiate the collapse of black holes in the early Universe and the finite duration of their collapse. Compared to the Gaussian description of the most extreme primordial density fluctuations, the holes' mass function is narrower and peaks towards larger masses. Secondly, thanks to the shallower fall-off of extreme-value distributions, the predicted abundance of primordial black holes is boosted by $10^7$ orders of magnitude when extrapolating the observed nearly scale-free power spectrum of the cosmic large-scale structure to primordial black-hole mass scales.

    ↳ astro-ph.COgr-qchep-phhep-th+24 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.