Thu·Mar 25, 2021Thursday·March 25, 2021

1. 01*

   Minimal Dark Matter bound states at future colliders

   Salvatore Bottaro🇮🇹 · Alessandro Strumia🇮🇹 · Natascia Vignaroli🇮🇹

   The hypothesis that Dark Matter is one electroweak multiplet leads to predictive candidates with multi-TeV masses that can form electroweak bound states. Bound states with the same quantum numbers as electroweak vectors are found to be especially interesting, as they can be produced resonantly with large cross sections at lepton colliders. Such bound states exist e.g. if DM is an automatically stable fermionic weak 5-plet with mass $M\approx$ 14 TeV such that the DM abundance is reproduced thermally. In this model, a muon collider could resolve three such bound states. Production rates are so large that details of DM spectroscopy can be probed with larger statistics: we compute the characteristic pattern of single and multiple $\gamma$ lines.

   hep-phhep-exJHEP(2021)·54 citations
2. 02*

   Electroproduction of $D$- and $B$-mesons in high-multiplicity $ep$ collisions

   Marat Siddikov🇨🇱 · Iván Schmidt🇨🇱

   In this paper we study the electroproduction of open heavy flavor $D$- and $B$-mesons in the kinematics of future $ep$ colliders, such as the Electron Ion Collider (EIC), the Large Hadron electron Collider (LHeC) and the Future Circular Collider (FCC-he). We study in detail the dependence of the cross-sections on multiplicity of co-produced hadrons, in view of its possible sensitivity to contributions from multipomeron contributions, and discuss different observables which might be used for its study. According to our theoretical expectations, in $ep$ collisions the multipomeron contributions are small in the EIC kinematics, although they might be sizable at LHeC and FCC-he. We also provide theoretical predictions for the production cross-sections of heavy mesons in the kinematics of all the above-mentioned $ep$ colliders.

   hep-phPRD(2021)·2 citations
3. 03*

   Effects of Intense Magnetic Fields, High Temperature and Density on QCD-Related Phenomena

   Jorge David Castaño-Yepes🇲🇽

   The effects of high-temperature, dense systems, and strong magnetic fields on Quantum Chromodynamics related phenomena are studied in different perspectives: in the high-temperature and densities, the QCD-phase diagram from the Linear Sigma Model point of view is computed. In particular, the CEP location and transition lines for chiral restoration were found. In the intense magnetic fields and high-gluon density, the gluon fusion and gluon splitting channels are proposed as new photon production sources to better explain the experimental data in the so-called "photon puzzle". Finally, the thermal and magnetic screening properties for gluons encoded into the polarization tensor were addressed in terms of the Debye mass.

   hep-ph5 citations
4. 04*

   The light invisible boson in FCNC decays of $B$ and $B_c$ mesons

   Geng Li🇨🇳 · Tianhong Wang🇨🇳 · Jing-Bo Zhang🇨🇳 · Guo-Li Wang🇨🇳

   In this paper, we study the FCNC decay processes of $B$ and $B_c$ meson, in which one invisible particle is emitted. Both the spin-0 and spin-1 cases are considered. The model-independent effective Lagrangian is introduced to describe the coupling between the light invisible boson and quarks. The constraints of the coupling coefficients are extracted by experimental upper limits of the missing energy in $B$ meson decays. The bounds are used to predict the upper limits of branching fractions of corresponding $B_c$ decays, which are of the order of $10^{-6}$ or $10^{-5}$ when final meson is pseudoscalar or vector, respectively. The maximum branch ratios are achieved when $m_{\chi }\approx 3.5-4$~GeV, where $m_{\chi }$ is the mass of the invisible particle.

   hep-phEPJC(2021)·8 citations
5. 05*

   Chiral dynamics and S-wave contributions in ${\bar{B}}^0/D^0\to {\pi }^{\pm }\eta l^{\mp }\nu$ decays

   Yu-Ji Shi🇩🇪 · Ulf-G. Meißner🇩🇪

   In this work, we analyze the semi-leptonic decays ${\bar{B}}^0/D^0\to (a_0(980{)}^{\pm }\to {\pi }^{\pm }\eta )l^{\mp }\nu$ within light-cone sum rules. The two and three-body light-cone distribution amplitudes (LCDAs) of the $B$ meson and the only available two-body LCDA of the $D$ meson are used. To include the finite-width effect of the $a_0(980)$, we use a scalar form factor to describe the final-state interaction between the $\pi \eta$ mesons, which was previously calculated within unitarized Chiral Perturbation Theory. The result for the decay branching fraction of the $D^0$ decay is in good agreement with that measured by the BESIII Collaboration, while the branching fraction of the ${\bar{B}}^0$ decay can be tested in future experiments.

   hep-phhep-exEPJC(2021)·6 citations
6. 06*

   Chiral non-Abelian vortices and their confinement in three flavor dense QCD

   Minoru Eto🇯🇵 · Muneto Nitta🇯🇵

   We find chiral non-Abelian vortices having windings only in one of the diquark condensations of left-handed and right-handed quarks in the color-flavor locked phase of dense QCD. They are the minimum vortices carrying half color magnetic fluxes of those of non-Abelian semi-superfluid vortices (color magnetic flux tubes) and 1/6 quantized superfluid circulations of Abelian superfluid vortices. These vortices carry $\mathbb{C}{P}^2$ orientational moduli in the internal space corresponding to their fluxes. The $\mathbb{C}{P}^2$ moduli of two chiral non-Abelian vortices with chiralities opposite to each other are energetically favored to be aligned while those of a vortex and anti-vortex to be orthogonal, and then these vortices attract each other. They are attached by chiral domain walls in the presence of the mass and axial anomaly terms explicitly breaking axial and chiral symmetries. We numerically show that two chiral non-Abelian vortices with chiralities opposite to each other are connected by a chiral domain wall, consisting a mesonic bound state which is nothing but a non-Abelian semi-superfluid vortex. We also show that Abelian and non-Abelian axial vortices attached by chiral domain walls are all unstable to decay into a set of chiral non-Abelian vortices. Furthermore, we find that chiral non-Abelian vortices exhibit unique features: one is the so-called topological obstruction implying that unbroken symmetry generators in the bulk are not defined globally around the vortices, and the other is color non-singlet Aharonov-Bohm (AB) phases implying that quarks encircling these vortices can detect the colors of magnetic fluxes of them at infinite distances.

   hep-phcond-mat.supr-conhep-thPRD(2021)·16 citations
7. 07*

   Prospect and implications of $cg\to b{H}^{+}\to bA{W}^{+}$ production at the LHC

   Wei-Shu Hou🇹🇼 · Tanmoy Modak🇩🇪

   We study the prospect for discovering the $cg\to b{H}^{+}\to bA{W}^{+}$ process at the LHC. Induced by the top-flavor changing neutral Higgs coupling ${\rho }_{tc}$, the process may emerge if $m_{H^{+}}>m_A+m_{W^{+}}$, where $H^{+}$ and $A$ are charged and $CP$-odd Higgs bosons in the general two Higgs Doublet Model (g2HDM). We show that the $cg\to b{H}^{+}\to bA{W}^{+}$ process can be discovered at LHC Run 3, while the full Run 2 data at hand can constrain the parameter space significantly by searching for the same-sign dilepton final state. The process has unique implications on the hint of $gg\to A\to t\bar{t}$ excess at $m_A\approx 400$ GeV reported by CMS. When combined with other existing constraints, the $cg\to b{H}^{+}\to bA{W}^{+}$ process can essentially rule out the g2HDM explanation of such an excess.

   hep-phhep-exPRD(2021)·6 citations
8. 08*

   Model comparison of the transverse momentum spectra of charged hadrons produced in $PbPb$ collision at $\sqrt{s_{NN}}=5.02$ TeV

   Rohit Gupta🇮🇳 · Satyajit Jena🇮🇳

   Transverse Momentum, $p_T$, spectra is of prime importance in order to extract crucial information about the evolution dynamics of the system of particles produced in the collider experiments. In this work, the transverse momentum spectra of charged hadrons produced in $PbPb$ collision at $5.02$ TeV has been analyzed using different distribution functions in order to gain strong insight into the information that can be extracted from the spectra. We have also discussed the applicability of Pearson distribution on the spectra of charged hadron at $5.02$ TeV.

   hep-phAdv.High Energy Phys.(2022)·10 citations
9. 09*

   Tetraquark state $X(6900)$ and the interaction between diquark and antidiquark

   Hong-Wei Ke🇨🇳 · Xin Han · Xiao-Hai Liu🇨🇳 · Yan-Liang Shi🇺🇸

   Recently LHCb declared a new structure $X(6900)$ in the final state di-$J/\psi$ which is popularly regarded as a $cc$-$\bar{c}\bar{c}$ tetraquark state. %popularly. Within the Bethe-Salpeter (B-S) frame we study the possible $cc$-$\bar{c}\bar{c}$ bound states and the interaction between diquark ($cc$) and antidiquark ($\bar{c}\bar{c}$). In this work $cc$ ($\bar{c}\bar{c}$) is treated as a color anti-triplet (triplet) axial-vector so the quantum numbers of $cc$-$\bar{c}\bar{c}$ bound state are $0^{+}$, $1^{+}$ and $2^{+}$. Learning from the interaction in meson case and using the effective coupling we suggest the interaction kernel for diquark and antidiquark system. Then we deduce the B-S equations for different quantum numbers. Solving these equations numerically we find the spectra of some excited states can be close to the mass of $X(6900)$ when we assign appropriate values for parameter $\kappa$ introduced in the interaction (kernel).We also briefly calculate the spectra of $bb$-$\bar{b}\bar{b}$ bound states. Future measurement of $bb$-$\bar{b}\bar{b}$ state will help us to determine the exact form of effective interaction.

   hep-phhep-exEPJC(2021)·70 citations
10. 10*

    Inverse seesaw and $(g-2)$ anomalies in $B-L$ extended two Higgs doublet model

    Tanmoy Mondal🇰🇷 · Hiroshi Okada🇰🇷

    We propose a gauged $U(1{)}_{B-L}$ extended two Higgs doublet model to explain both neutrino mass and lepton anomalous magnetic moments ($g-2$). Neutrino mass is generated via an inverse seesaw mechanism by introducing singlet fermions. Especially, we update the result of muon $g-2$ in light of the very recent report by E989 experiment at Fermilab, indicating $a_{\mu }^{\mathrm{FNAL}}=116592040(54)\times 10^{-11}$. Combining BNL result, we have the following deviation from the standard model prediction $\Delta a_{\mu }=(2.51\pm 5.9)\times 10^{-10}$ at 4.2 $\sigma$. Thanks to an appropriate assignment for $U(1{)}_{B-L}\times Z_2$ symmetry and larger $(20\lesssim )\tan \beta$ that is favoured by type-X model, we realize natural hierarchies among neutral fermions. The lepton anomalous magnetic moments can be induced at the one loop level by introducing an iso-spin singlet singly-charged boson. This charged scalar plays a significant role in evading chiral suppression of these phenomenologies. We show sizable lepton ($g-2$) can be obtained after satisfying all the flavour constraints, such as $\mu \to e\gamma$ and flavour conserving leptonic $Z$ boson decays.

    hep-phNPB(2022)·25 citations
11. 11*

    Magnetic field induced neutrino chiral transport near equilibrium

    Naoki Yamamoto🇯🇵 · Di-Lun Yang🇯🇵

    Based on the recently formulated chiral radiation transport theory for left-handed neutrinos, we study the chiral transport of neutrinos near thermal equilibrium in core-collapse supernovae. We first compute the near-equilibrium solution of the chiral radiation transport equation under the relaxation time approximation, where the relaxation time is directly derived from the effective field theory of the weak interaction. By using such a solution, we systematically derive analytic expressions for the nonequilibrium corrections of the neutrino energy-momentum tensor and neutrino number current induced by magnetic fields via the neutrino absorption on nucleons. In particular, we find the nonequilibrium neutrino energy current proportional to the magnetic field. We also discuss its phenomenological consequences such as the possible relation to pulsar kicks.

    hep-phastro-ph.HEnucl-thPRD(2021)·15 citations
12. 12*

    Axion Cloud Decay due to the Axion-photon Conversion with Background Magnetic Fields

    Chul-Moon Yoo🇯🇵 · Atsushi Naruko🇯🇵 · Yusuke Sakurai🇯🇵 · Keitaro Takahashi🇯🇵 · Yohsuke Takamori🇯🇵 · Daisuke Yamauchi🇯🇵

    We consider an axion cloud around a black hole with background magnetic fields. We calculate the decay rate of the axion cloud due to the axion-photon conversion associated with the axion-photon coupling. For simplicity, we consider the situation where the axion configuration is dominated by a solution for the eigenvalue equation equivalent to that for the Hydrogen atom, and the coupling term can be evaluated by a successive perturbation method. For the monopole background, we find the decay rate of the axion cloud is given by $\sim q^2{\kappa }^2(GM{)}^5{\mu }^8$, where $\mu$, $M$, $G$, $\kappa$ and $q$ are the axion mass, black hole mass, gravitational constant, coupling constant of the axion-photon coupling and monopole charge, respectively. For the uniform background magnetic field, we obtain the decay rate of the axion cloud $\sim B_0^2{\kappa }^2(GM{)}^7{\mu }^6$, where $B_0$ is the magnetic field strength. Applying our formula to the central black hole in our galaxy, we find that the value of the decay rate for the case of the uniform magnetic field is comparable to the growth rate of the superradiant instability with $\kappa \sim 10^{-12}\mathrm{Ge}{\mathrm{V}}^{-1}$, $B_0\sim 10^3\mathrm{G}$ and $\mu \sim 10^{-18}\mathrm{eV}$. The ratio is $10^5$ times larger for the monopole magnetic field with the same values of the parameters.

    hep-phastro-ph.COgr-qchep-thPubl.Astron.Soc.Jap.(2022)·5 citations
13. 13*

    New Physics in Rare B Decays after Moriond 2021

    Wolfgang Altmannshofer🇺🇸 · Peter Stangl🇨🇭

    The anomalies in rare $B$ decays endure. We present results of an updated global analysis that takes into account the latest experimental input -- in particular the recent results on $R_K$ and BR$(B_s\to {\mu }^{+}{\mu }^{-})$ -- and that qualitatively improves the treatment of theory uncertainties. Fit results are presented for the Wilson coefficients of four-fermion contact interactions. We find that muon specific Wilson coefficients $C_9\simeq -0.73$ or $C_9=-C_{10}\simeq -0.39$ continue to give an excellent description of the data. If only theoretically clean observables are considered, muon specific $C_{10}\simeq 0.60$ or $C_9=-C_{10}\simeq -0.35$ improve over the Standard Model by $\sqrt{\Delta {\chi }^2}\simeq 4.7\sigma$ and $\sqrt{\Delta {\chi }^2}\simeq 4.6\sigma$, respectively. In various new physics scenarios we provide predictions for lepton flavor universality observables and CP asymmetries that can be tested with more data. We update our previous combination of ATLAS, CMS, and LHCb data on BR$(B_s\to {\mu }^{+}{\mu }^{-})$ and BR$(B^0\to {\mu }^{+}{\mu }^{-})$ taking into account the full two-dimensional non-Gaussian experimental likelihoods.

    hep-phhep-exEPJC(2021)·328 citations
14. 14*

    Bounds on Gauge Bosons Coupled to Non-conserved Currents

    Majid Ekhterachian🇺🇸 · Anson Hook🇺🇸 · Soubhik Kumar🇺🇸 · Yuhsin Tsai🇺🇸

    We discuss new bounds on vectors coupled to currents whose non-conservation is due to mass terms, such as $U(1{)}_{L_{\mu }-L_{\tau }}$. Due to the emission of many final state longitudinally polarized gauge bosons, inclusive rates grow exponentially fast in energy, leading to constraints that are only logarithmically dependent on the symmetry breaking mass term. This exponential growth is unique to Stueckelberg theories and reverts back to polynomial growth at energies above the mass of the radial mode. We present bounds coming from the high transverse mass tail of mono-lepton+missing transverse energy events at the LHC, which beat out cosmological bounds to place the strongest limit on Stueckelberg $U(1{)}_{L_{\mu }-L_{\tau }}$ models for most masses below a keV. We also discuss a stronger, but much more uncertain, bound coming from the validity of perturbation theory at the LHC.

    hep-phastro-ph.COPRD(2021)·19 citations
15. 15*

    Baryogenesis via Leptogenesis: Spontaneous B and L Violation

    Pavel Fileviez Perez🇺🇸 · Clara Murgui🇺🇸 · Alexis D. Plascencia🇺🇸

    In order to address the baryon asymmetry in the Universe one needs to understand the origin of baryon (B) and lepton (L) number violation. In this article, we discuss the mechanism of baryogenesis via leptogenesis to explain the matter-antimatter asymmetry in theories with spontaneous breaking of baryon and lepton number. In this context, a lepton asymmetry is generated through the out-of-equilibrium decays of right-handed neutrinos at the high-scale, while local baryon number must be broken below the multi-TeV scale to satisfy the cosmological bounds on the dark matter relic density. We demonstrate how the lepton asymmetry generated via leptogenesis can be converted in two different ways: a) in the theory predicting Majorana dark matter the lepton asymmetry is converted into a baryon asymmetry, and b) in the theory with Dirac dark matter the decays of right-handed neutrinos can generate lepton and dark matter asymmetries that are then partially converted into a baryon asymmetry. Consequently, we show how to explain the matter-antimatter asymmetry, the dark matter relic density and neutrino masses in theories for local baryon and lepton number.

    hep-phhep-exPRD(2021)·24 citations
16. 16*

    Radiative Muon Mass Models and $(g-2{)}_{\mu }$

    Michael J. Baker🇦🇺 · Peter Cox🇦🇺 · Raymond R. Volkas🇦🇺

    Recent measurements of the Higgs-muon coupling are directly probing muon mass generation for the first time. We classify minimal models with a one-loop radiative mass mechanism and show that benchmark models are consistent with current experimental results. We find that these models are best probed by measurements of $(g-2{)}_{\mu }$, even when taking into account the precision of Higgs measurements expected at future colliders. The current $(g-2{)}_{\mu }$ anomaly, if confirmed, could therefore be a first hint that the muon mass has a radiative origin.

    hep-phJHEP(2021)·45 citations
17. 17*

    Improved $(g-2{)}_{\mu }$ Measurements and Wino/Higgsino Dark Matter

    Manimala Chakraborti🇵🇱 · Sven Heinemeyer🇪🇸 · Ipsita Saha🇯🇵

    The electroweak (EW) sector of the Minimal Supersymmetric Standard Model (MSSM) can account for a variety of experimental data. In particular, it can explain the persistent 3-4 sigma discrepancy between the experimental result for the anomalous magnetic moment of the muon and its Standard Model (SM) prediction. The lightest supersymmetric particle (LSP), which we take as the lightest neutralino, can furthermore account for the observed Dark Matter (DM) content of the universe via coannihilation with the next-to-LSP (NLSP), while being in agreement with negative results from Direct Detection (DD) experiments. Concerning the unsuccessful searches for EW superparticles at the LHC, owing to relatively small production cross-sections, a comparably light EW sector of the MSSM is in full agreement with the experimental data. The DM relic density can fully be explained by a mixed bino/wino LSP. Here we take the relic density as an upper bound, which opens up the possibility of wino and higgsino DM. We first analyze which mass ranges of neutralinos, charginos and scalar leptons are in agreement with all experimental data, including relevant LHC searches. We find roughly an upper limit of ~ 600 GeV for the LSP and NLSP masses. In a second step we assume that the new result of the Run 1 of the 'MUON G-2' collaboration at Fermilab yields a precision comparable to the existing experimental result with the same central value. We analyze the potential impact of the combination of the Run 1 data with the existing muon g-2 data on the allowed MSSM parameter space. We find that in this case the upper limits on the LSP and NLSP masses are substantially reduced by roughly 100 GeV. We interpret these upper bounds in view of future HL-LHC EW searches as well as future high-energy electron-positron colliders, such as the ILC or CLIC.

    hep-phEPJC(2021)·58 citations
18. 18*

    Addressing the CKM Unitarity Problem with a Vector-like Up Quark

    G. C. Branco🇵🇹 · J. T. Penedo🇵🇹 · Pedro M. F. Pereira🇵🇹 · M. N. Rebelo🇵🇹 · J. I. Silva-Marcos🇵🇹

    We point out that hints of deviations from unitarity in the first row of the CKM matrix may be explained by the presence of a single vector-like top. We study how the stringent experimental constraints arising from CP Violation in the kaon sector and from meson mixing such as $D^0$-${\overline{D}}^0$, $K^0$-${\overline{K}}^0$ and $B_{d,s}^0$-${\overline{B}}_{d,s}^0$ can be satisfied in the proposed framework. In order for the deviations from unitarity to be of the required size while keeping the theory perturbative, the new top quark should have a mass $m_T\lesssim 7$ TeV which could be probed in upcoming experiments at the energy frontier.

    hep-phJHEP(2021)·71 citations
19. 19*

    Quantum Field Theory of Space-like Neutrino

    Jakub Rembieliński🇵🇱 · Paweł Caban🇵🇱 · Jacek Ciborowski🇵🇱

    We performed a Lorentz covariant quantization of the spin-1/2 fermion field assuming the space-like energy-momentum dispersion relation. We a\-chieved the task in the following steps: ($i$) determining the unitary realizations of the inhomogenous Lorentz group in the preferred frame scenario by means of the Wigner-Mackey induction procedure and constructing the Fock space; ($ii$) formulating the theory in a manifestly covariant way by constructing the field amplitudes according to the Weinberg method; ($iii$) obtaining the final constraints on the amplitudes by postulating a Dirac-like free field equation. Our theory allows to predict all chiral properties of the neutrinos, preserving the Standard Model dynamics. We discussed the form of the fundamental observables, energy and helicity, and show that non-observation of the $+\frac{1}{2}$ helicity state of the neutrino and the $-\frac{1}{2}$ helicity state of the antineutrino could be a direct consequence of the "tachyoneity" of neutrinos at the free level. We found that the free field theory of the space-like neutrino is not invariant under the C and P transformations separately but is CP-invariant. We calculated and analyzed the electron energy spectrum in tritium decay within the framework of our theory and found an excellent agreement with the recent measurement of KATRIN. In our formalism the questions of negative/imaginary energies and the causality problem does not appear.

    hep-phhep-thEPJC(2021)·9 citations
20. 20*

    Search for High-Energy Neutrino Emission from Radio-Bright AGN

    Bei Zhou🇺🇸 · Marc Kamionkowski🇺🇸 · Yun-feng Liang🇨🇳

    We investigate the possibility that radio-bright active galactic nuclei (AGN) are responsible for the TeV--PeV neutrinos detected by IceCube. We use an unbinned maximum-likelihood-ratio method, 10 years of IceCube muon-track data, and 3388 radio-bright AGN selected from the Radio Fundamental Catalog. None of the AGN in the catalog have a large global significance. The two most significant sources have global significance of $\simeq$ 1.5$\sigma$ and 0.8$\sigma$, though 4.1$\sigma$ and 3.8$\sigma$ local significance. Our stacking analyses show no significant correlation between the whole catalog and IceCube neutrinos. We infer from the null search that this catalog can account for at most 30\% (95\% CL) of the diffuse astrophysical neutrino flux measured by IceCube. Moreover, our results disagree with recent work that claimed a 4.1$\sigma$ detection of neutrinos from the sources in this catalog, and we discuss the reasons of the difference.

    ↳ astro-ph.HEastro-ph.GAhep-phPRD(2021)·80 citations
21. 21*

    One-loop multicollinear limits from 2-point amplitudes on self-dual backgrounds

    Tim Adamo🇬🇧 · Anton Ilderton🇬🇧 · Alexander J. MacLeod🇬🇧

    For scattering amplitudes in strong background fields, it is -- at least in principle -- possible to perturbatively expand the background to obtain higher-point vacuum amplitudes. In the case of self-dual plane wave backgrounds we consider this expansion for two-point, one-loop amplitudes in pure Yang-Mills, QED and QCD. This enables us to obtain multicollinear limits of 1-loop vacuum amplitudes; the resulting helicity configurations are surprisingly restricted, with only the all-plus helicity amplitude surviving. These results are shown to be consistent with well-known vacuum amplitudes. We also show that for both abelian and non-abelian supersymmetric gauge theories, there is no helicity flip (and hence no vacuum birefringence) on any plane wave background, generalising a result previously known in the Euler-Heisenberg limit of super-QED.

    ↳ hep-thhep-phJHEP(2021)·18 citations
22. 22*

    Nucleon isovector scalar charge from overlap fermions

    Liuming Liu🇨🇳 · Ting Chen🇨🇳 · Terrence Draper🇺🇸 · Jian Liang🇨🇳 · Keh-Fei Liu🇺🇸 · Gen Wang🇺🇸 · Yi-Bo Yang🇨🇳

    We calculate the nucleon isovector scalar charge in lattice QCD using overlap fermions on five ensembles of gauge configurations generated by the RBC/UKQCD collaboration using the domain-wall quark action with $2+1$ dynamical flavors. The five ensembles cover five pion masses, $m_{\pi }\approx$ 139, 171, 302, 337 and 371 MeV, and four lattice spacings, $a\approx$ 0.06, 0.08, 0.11 and 0.14 fm. Three to six valence quark masses are computed on each ensemble to investigate the pion mass dependence. The extrapolation to the physical pion mass, continuum and infinite volume limits is obtained by a global fit of all data to a formula originated from partially quenched chiral perturbation theory. The excited-states contamination is carefully analyzed with 3--5 sink-source separations and multi-state fits. Our final result, in the $\overline{\text{MS}}$ scheme at 2 GeV, is $g_S^{u-d}=0.94(10{)}_{stat}(8{)}_{sys}$, where the first error is the statistical error and the second is the systematic error.

    ↳ hep-lathep-phPRD(2021)·12 citations
23. 23*

    Squeezed spectra of bosons and antibosons with different in-medium masses

    Yong Zhang🇨🇳 · Hui-Qiang Ding🇨🇳 · Shi-Yao Wang🇨🇳

    We study the influence of the in-medium mass difference between boson and antiboson on their spectra. The in-medium mass difference may lead to a difference between the transverse momentum spectra of boson and antiboson. This effect increases with the increasing in-medium mass difference between boson and antiboson. The difference between the transverse momentum spectra of boson and antiboson increases with the increasing expanding velocity of the source and decreases with the increasing transverse momentum in large transverse mass region (mT > 1:6 GeV). The interactions between the hadron and the medium may increase with the increasing temperature of the medium and the higher freeze-out temperature may lead to a larger mass difference between boson and antiboson, and may give rise to a larger difference between the transverse momentum spectra of boson and antiboson for higher freeze-out temperature.

    ↳ nucl-thhep-phIJMPE(2021)·3 citations
24. 24*

    Minimal $k$-inflation in light of the conformal metric-affine geometry

    Yusuke Mikura🇯🇵 · Yuichiro Tada🇯🇵 · Shuichiro Yokoyama🇯🇵

    We motivate a minimal realization of slow-roll $k$-inflation by incorporating the local conformal symmetry and the broken global $\mathrm{SO}(1,1)$ symmetry in the metric-affine geometry. With use of the metric-affine geometry where both the metric and the affine connection are treated as independent variables, the local conformal symmetry can be preserved in each term of the Lagrangian and thus higher derivatives of scalar fields can be easily added in a conformally invariant way. Predictions of this minimal slow-roll $k$-inflation, $n_{\mathrm{s}}\sim 0.96$, $r\sim 0.005$, and $c_{\mathrm{s}}\sim 0.03$, are not only consistent with current observational data but also have a prospect to be tested by forthcoming observations.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2021)·33 citations
25. 25*

    Implications for the hierarchy problem, inflation and geodesic motion from fiber fabric of spacetime

    Cao H. Nam🇻🇳

    In this paper, we represent a resolution for the hierarchy problem where the inverse size of the extra dimension and the fundamental Planck scale would all be of the order of the TeV scale by proposing a fiber fabric of spacetime. The origin of the large hierarchy is essentially due to the $\cosh$ function which has a physical origin from the dynamics of the horizontal metric in the vacuum of non-zero energy. In addition, the fiber fabric of spacetime allows us to resolve elegantly and naturally the problems of the chirality fermions and stabilizing potential for the size of the extra dimension, which are usually encountered in the higher dimensional theories. Then, we explore the inflation with the modulus of the extra dimension identified as the inflaton where our slow-roll inflationary model belongs to the E-model class with $n=1$. We calculate the main inflationary observables which are consistent with the present experiments. Finally, we study how the geodesic motion of neutral test particles gets modified from the extension of spacetime. We compute the radius of the photon sphere, the innermost stable circular orbit, the perihelion shift, the light bending angle, and the observables of the strong gravitational lensing and the retrolensing phenomenon. By comparing the predicted values with the experimental observations, we determine the constraints on the fiber fabric of spacetime.

    ↳ hep-thgr-qchep-phEPJC(2021)·13 citations
26. 26*

    Helical magnetic effect and the chiral anomaly

    Naoki Yamamoto🇯🇵 · Di-Lun Yang🇹🇼

    In the presence of the fluid helicity $\mathbf{v}\cdot \mathbf{\omega }$, the magnetic field induces an electric current of the form $\mathbf{j}=C_{\mathrm{HME}}(\mathbf{v}\cdot \mathbf{\omega })\mathbf{B}$. This is the helical magnetic effect (HME). We show that for massless Dirac fermions with charge $e=1$, the transport coefficient $C_{\mathrm{HME}}$ is fixed by the chiral anomaly coefficient $C=1/(2{\pi }^2)$ as $C_{\mathrm{HME}}=C/2$ independently of interactions. We show the conjecture that the coefficient of the magnetovorticity coupling for the local vector charge, $n=C_{B\omega }\mathbf{B}\cdot \mathbf{\omega }$, is related to the chiral anomaly coefficient as $C_{B\omega }=C/2$. We also discuss the condition for the emergence of the helical plasma instability that originates from the HME.

    ↳ hep-thastro-ph.HEcond-mat.mes-hallhep-phPRD(2021)·16 citations
27. 27*

    Searches for sterile neutrinos and axionlike particles from the Galactic halo with eROSITA

    Ariane Dekker🇳🇱 · Ebo Peerbooms🇳🇱 · Fabian Zimmer🇳🇱 · Kenny C. Y. Ng🇳🇱 · Shin'ichiro Ando🇳🇱

    Dark matter might be made of "warm" particles, such as sterile neutrinos in the keV mass range, which can decay into photons through mixing and are consequently detectable by X-ray telescopes. Axionlike particles (ALPs) are detectable by X-ray telescopes too when coupled to standard model particles and decay into photons in the keV range. Both particles could explain the unidentified 3.5 keV line and, interestingly, XENON1T observed an excess of electron recoil events most prominent at 2-3 keV. One explanation could be an ALPs origin, which is not yet excluded by X-ray constraints in an anomaly-free symmetry model in which the photon production is suppressed. We study the diffuse emission coming from the Galactic halo, and calculate the sensitivity of all-sky X-ray survey performed by eROSITA to identify a sterile neutrino or ALP dark matter. We estimate bounds on the mixing angle of the sterile neutrinos and coupling strength of the ALPs. After four years of data-taking by eROSITA, we expect to set stringent constraints, and in particular, we expect to firmly probe mixing angle ${\sin }^2(2\theta )$ up to nearly two orders magnitude below the best-fit value for explaining the unidentified 3.5 keV line. Moreover, with eROSITA, we will be able to probe the ALP parameter space of couplings to photons and electrons, and potentially confirm an ALP origin of the XENON1T excess.

    ↳ astro-ph.HEastro-ph.COhep-phPRD(2021)·58 citations
28. 28*

    Decaying dark matter in dwarf spheroidal galaxies: Prospects for X-ray and gamma-ray telescopes

    Shin'ichiro Ando🇳🇱 · Suvendu K. Barik🇳🇱 · Zhuoran Feng🇳🇱 · Marco Finetti🇳🇱 · Andreas Guerra Chaves🇳🇱 · Sahaja Kanuri🇳🇱 · Jorinde Kleverlaan🇳🇱 · Yixuan Ma🇳🇱 · Nicolo Maresca Di Serracapriola🇳🇱 · Matthew S. P. Meinema🇳🇱 · Imanol Navarro Martinez🇳🇱 · Kenny C. Y. Ng🇳🇱 and 3 other authors

    Dwarf spheroidal galaxies are dark matter dominated systems, and as such, ideal for indirect dark matter searches. If dark matter decays into high-energy photons in the dwarf galaxies, they will be a good target for current and future generations of X-ray and gamma-ray telescopes. By adopting the latest estimates of density profiles of dwarf galaxies in the Milky Way, we revise the estimates dark matter decay rates in dwarf galaxies; our results are more robust, but weaker than previous estimates. Applying these results, we study the detectability of dark matter decays with X-ray and very-high-energy gamma-ray telescopes, such as eROSITA, XRISM, Athena, HAWC, and CTA. Our projection shows that all of these X-ray telescopes will be able to critically assess the claim of the 7 keV sterile neutrino decays from stacked galaxy clusters and nearby galaxies. For TeV decaying dark matter, we can constrain its lifetime to be longer than $\sim$10${}^{27}$-10${}^{28}$ s. We also make projections for future dwarf galaxies that would be newly discovered with the Vera Rubin Observatory Legacy Survey of Space and Time, which will further improve the expected sensitivity to dark matter decays both in the keV and PeV mass ranges.

    ↳ astro-ph.HEastro-ph.COhep-phPRD(2021)·33 citations
29. 29*

    Wilsonian Effective Field Theory and String Theory

    S.P. de Alwis🇺🇸

    We argue that deriving an effective field theory from string theory requires a Wilsonian perspective with a physical cutoff. Employing proper time regularization we demonstrate the decoupling of states and contrast this with what happens in dimensional regularization. In particular we point out that even if the cosmological constant (CC) calculated from some classical action at some ultra-violet scale is negative, this does not necessarily imply that the CC calculated at cosmological scales is also negative, and discuss the possible criteria for achieving a positive CC starting with a CC at the string/KK scale which is negative. Obviously this has implications for swampland claims.

    ↳ hep-thgr-qchep-ph6 citations
30. 30*

    SMBH Seeds from Dissipative Dark Matter

    Huangyu Xiao🇺🇸 · Xuejian Shen🇺🇸 · Philip F. Hopkins🇺🇸 · Kathryn M. Zurek🇺🇸

    The existence of supermassive black holes (SMBHs) with masses greater than $\sim 10^9{M}_{\odot }$ at high redshift ($z\gtrsim 7$) is difficult to accommodate in standard astrophysical scenarios. We study the possibility that (nearly) totally dissipative self-interacting dark matter (tdSIDM)--in rare, high density dark matter fluctuations in the early Universe--produces SMBH seeds through catastrophic collapse. We use a semi-analytic model, tested and calibrated by a series of N-body simulations of isolated dark matter halos, to compute the collapse criteria and timescale of tdSIDM halos, where dark matter loses nearly all of its kinetic energy in a single collision in the center-of-momentum frame. Applying this model to halo merger trees, we empirically assign SMBH seeds to halos and trace the formation and evolution history of SMBHs. We make predictions for the quasar luminosity function, the $M_{\mathrm{BH}}$-${\sigma }_{\mathrm{v}}^{\ast }$ relation, and cosmic SMBH mass density at high redshift and compare them to observations. We find that a dissipative dark matter interaction cross-section of $\sigma /m\sim 0.05\mathrm{c}{\mathrm{m}}^2/g$ is sufficient to produce the SMBHs observed in the early Universe while remaining consistent with ordinary SMBHs in the late Universe.

    ↳ astro-ph.COhep-phJCAP(2021)·44 citations
31. 31*

    Dark matter and dark radiation from evaporating Kerr primordial black holes

    Isabella Masina🇮🇹

    The mechanism of the generation of dark matter and dark radiation from the evaporation of primordial black holes is very interesting. We consider the case of Kerr black holes to generalize previous results obtained in the Schwarzschild case. For dark matter, the results do not change dramatically and the bounds on warm dark matter apply similarly: in particular, the Kerr case cannot save the scenario of black hole domination for light dark matter. For dark radiation, the expectations for $\Delta N_{eff}$ do not change significantly with respect to the Schwarzschild case, but for an enhancement in the case of spin 2 particles: in the massless case, however, the projected experimental sensitivity would be reached only for extremal black holes.

    ↳ gr-qcastro-ph.COhep-phGrav.Cosmol.(2021)·90 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.