Fri·Apr 9, 2021Friday·April 9, 2021

1. 01*

   Muon Anomalous Magnetic Moment and Higgs Potential Stability in the 331 Model from $SU(6)$

   Tianjun Li🇨🇳 · Junle Pei🇨🇳 · Wenxing Zhang🇨🇳

   We consider a $SU(3{)}_c\times SU(3{)}_L\times U(1{)}_X$ model from a $SU(6)$ Grand Unified Theory (GUT). In order to explain the anomalous magnetic moments of muon and electron, we introduce two new scalar triplets without vacuum expectation values (VEVs) so that the leading contributions to $\Delta a_{\mu }$ and $\Delta a_e$ can avoid the suppression from small muon mass. In addition, the Higgs potential stability of this 331 model is studied by giving a set of sufficient conditions to ensure the boundedness from below of the potential.

   hep-phEPJC(2021)·21 citations
2. 02*

   Constraining $U(1{)}_{L_{\mu }-L_{\tau }}$ charged dark matter model for muon $g-2$ anomaly with AMS-02 electron and positron data

   Lei Zu🇨🇳 · Xu Pan🇨🇳 · Lei Feng🇨🇳 · Qiang Yuan🇨🇳 · Yi-Zhong Fan🇨🇳

   Very recently, the Fermi-Lab reported the new experimental combined results on the magnetic momentum of muon with a 4.2$\sigma$ discrepancy compared with the expectation of the Standard Model \cite{Fermi_Lab}. A new light gauge boson $X$ in the $L_{\mu }-L_{\tau }$ model provides a good explanation for the $g-2$ anomaly. A Dirac fermion dark matter with a large $L_{\mu }-L_{\tau }$ charge can explain both the $g-2$ anomaly and the dark matter relic density \cite{Asai_2021}. In this work, we focus on the case that the mass of the dark matter is larger than the mass of muon (i.e. $m_{\Psi }>m_{\mu }$) for which the channel $\Psi \Psi \to {\mu }^{-}{\mu }^{+}$ opens. Although the cross section $(\sigma v{)}_{{\mu }^{-}{\mu }^{+}}$ is smaller by a factor of $1/q_{\Psi }^2$ ($q_{\Psi }$ represents the $L_{\mu }-L_{\tau }$ charge of the dark matter) compared with the channel $\Psi \Psi \to XX\to \nu \nu \bar{\nu }\bar{\nu }$, the resulting secondary electrons and positrons could imprint on their spectra above GeV energies due to the reacceleration effect of cosmic ray propagation. We use the AMS-02 measurements of electrons and positrons to constrain the annihilation cross section of the channel $\Psi \Psi \to {\mu }^{-}{\mu }^{+}$, which rules out part of the parameter space of the large $L_{\mu }-L_{\tau }$ charged dark matter model to account for the muon $g-2$ anomaly.

   hep-phJCAP(2022)·29 citations
3. 03*

   Axion-like particles, two-Higgs-doublet models, leptoquarks, and the electron and muon g-2

   Wai-Yee Keung🇺🇸 · Danny Marfatia🇺🇸 · Po-Yan Tseng🇰🇷

   Data from the Muon g-2 experiment and measurements of the fine structure constant suggest that the anomalous magnetic moments of the muon and electron are at odds with standard model expectations. We survey the ability of axion-like-particles, two-Higgs-doublet models and leptoquarks to explain the discrepancies. We find that accounting for other constraints, all scenarios except the Type-I, Type-II and Type-Y two-Higgs-doublet models fit the data well.

   hep-phhep-exLHEP(2021)·32 citations
4. 04*

   The Higgs Portal to Cosmology

   Oleg Lebedev🇫🇮

   The discovery of the Higgs boson has opened a new avenue for exploring physics beyond the Standard Model. In this review, we discuss cosmological aspects of the simplest Higgs couplings to the hidden sector, known as the Higgs portal. We focus on implications of such couplings for inflation, vacuum stability and dark matter, with the latter including both the traditional weakly interacting massive particles as well as feebly interacting scalars. The cosmological impact of the Higgs portal can be important even for tiny values of the couplings.

   hep-phastro-ph.COPPNP(2021)·94 citations
5. 05*

   Dark Matter and Collider Searches in $S_3$-Symmetric 2HDM with Vector Like Leptons

   Indrani Chakraborty🇮🇳 · Dilip Kumar Ghosh🇮🇳 · Nivedita Ghosh🇮🇳 · Santosh Kumar Rai🇮🇳

   We study the $S_3$-symmetric two Higgs doublet model by adding two generations of vector like leptons (VLL) which are odd under a discrete $Z_2$ symmetry. The lightest neutral component of the VLL acts as a dark matter (DM) whereas the full VLL set belongs to a dark sector with no mixings allowed with the standard model fermions. We analyse the model in light of dark matter and collider searches. We show that the DM is compatible with the current relic density data as well as satisfying all direct and indirect dark matter search constraints. We choose some representative points in the model parameter space allowed by all aforementioned dark matter constraints and present a detailed collider analysis of multi-lepton signal viz. the mono-lepton, di-lepton, tri-lepton and four-lepton along with missing transverse energy in the final state using both the cut-based analysis and multivariate analysis respectively at the high luminosity 14 TeV LHC run.

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

   $(g-2{)}_{\mu }$ in the 2HDM and slightly beyond -- an updated view

   P.M. Ferreira🇵🇹 · B. L. Gonçalves🇵🇹 · F. R. Joaquim🇵🇹 · Marc Sher🇺🇸

   The recent measurement of the muon $g-2$ anomaly continues to defy a Standard Model explanation, but can be accommodated within the framework of two Higgs doublet models. If one further includes extra fermion content in the form of a generation of vector like leptons, the allowed parameter range that explains the anomaly is even further extended, and thorny issues of perturbativity and clashes with $B$-decay constraints avoided. We will show how the muon magnetic moment anomaly can be fit within these models, under the assumption that the vector-like leptons do not mix with the muon. We update previous analyses and include all theoretical and experimental constraints, including searches for extra scalars. It is shown that the inclusion of vector-like fermions allows the lepton-specific and muon-specific models to perform much better in fitting the muon's $g-2$. These fits do require the Yukawa coupling between the Higgs and the vector-like leptons to be large, causing potential problems with perturbativity and unitarity, and thus models in which the vector-like leptons mix with the muon may be preferred.

   hep-phPRD(2021)·39 citations
7. 07*

   Muon anomalous magnetic dipole moment in the $\mu \nu$SSM

   Hai-Bin Zhang🇨🇳 · Chang-Xin Liu🇨🇳 · Jin-Lei Yang🇨🇳 · Tai-Fu Feng🇨🇳

   Recently, the Muon g-2 experiment at Fermilab has measured the muon anomalous magnetic dipole moment (MDM), $a_{\mu }=(g_{\mu }-2)/2$, which reported that the new experimental average increases the tension between experiment and the standard model (SM) prediction to 4.2$\sigma$. In this work, we reanalyse the muon anomalous MDM at two-loop level in the $\mu$ from $\nu$ Supersymmetric Standard Model ($\mu \nu$SSM) combined with the updated experimental average. The $\mu \nu$SSM can explain the current tension between the experimental measurement and the SM theoretical prediction for the muon anomalous MDM, constrained by the 125 GeV Higgs boson mass and decays, the rare decay $\bar{B}\to X_s\gamma$ and so on. We also investigate the anomalous MDM of the electron and tau lepton, $a_e=(g_e-2)/2$ and $a_{\tau }=(g_{\tau }-2)/2$, at two-loop level in the $\mu \nu$SSM. In addition, the 125 GeV Higgs boson decays to a pair of charged leptons in the $\mu \nu$SSM are also analysed.

   hep-phhep-exCPC(2022)·37 citations
8. 08*

   The Natural Explanation of the Muon Anomalous Magnetic Moment via the Electroweak Supersymmetry from the GmSUGRA in the MSSM

   Waqas Ahmed🇨🇳 · Imtiaz Khan🇨🇳 · Jinmian Li🇨🇳 · Tianjun Li🇨🇳 · Shabbar Raza🇵🇰 · Wenxing Zhang🇨🇳

   The Fermi-Lab Collaboration has announced the results for the measurement of muon anomalous magnetic moment. Combining with the previous results by the BNL experiment, we have $4.2\sigma$ deviation from the Standard Model (SM), which strongly implies the new physics around 1 TeV. To explain the muon anomalous magnetic moment naturally, we analyze the corresponding five Feynman diagrams in the Supersymetric SMs (SSMs), and show that the Electroweak Supersymmetry (EWSUSY) is definitely needed. We realize the EWSUSY in the Minimal SSM (MSSM) with Genernalized Mininal Supergravity (GmSUGRA). We find large viable parameter space, which is consistent with all the current experimental constraints. In particular, the Lightest Supersymmetric Particle (LSP) neutralino can be at least as heavy as 550 GeV. Most of the viable parameter space can be probed at the future HL-LHC, while we do need the future HE-LHC to probe some viable parameter space. However, it might still be challenge if R-parity is violated.

   hep-phPLB(2022)·49 citations
9. 09*

   Probing new physics for $(g-2{)}_{\mu }$ and gravitational waves

   Ruiyu Zhou🇨🇳 · Ligong Bian🇨🇳 · Jing Shu🇨🇳

   We study the possibility of probing new physics accounting for $(g-2{)}_{\mu }$ anomaly and gravitational waves with pulsar timing array measurements. The model we consider is either a light gauge boson or neutral scalar interacting with muons. We show that the parameter spaces of dark $U(1)$ model with kinetic mixing explaining $(g-2{)}_{\mu }$ anomaly can realize a first-order phase transition, and the yield-produced gravitational wave may address the common red noise observed in the NANOGrav 12.5-yr dataset.

   hep-phastro-ph.COgr-qc12 citations
10. 10*

    Muon $(g-2)$ in the B-LSSM

    Jin-Lei Yang🇨🇳 · Hai-Bin Zhang🇨🇳 · Chang-Xin Liu🇨🇳 · Xing-Xing Dong🇨🇳 · Tai-Fu Feng🇨🇳

    The difference between the updated experimental result on the muon anomalous magnetic dipole moment and the corresponding theoretical prediction of the standard model on that is about $4.2$ standard deviations. In this work, we calculate the muon anomalous MDM at the two-loop level in the supersymmetric $B-L$ extension of the standard model. Considering the experimental constraints on the lightest Higgs boson mass, Higgs boson decay modes $h\to \gamma \gamma ,WW,ZZ,b\bar{b},\tau \bar{\tau }$, B rare decay $\bar{B}\to X_s\gamma$, and the transition magnetic moments of Majorana neutrinos, we analyze the theoretical predictions of the muon anomalous magnetic dipole moment in the $B-L$ supersymmetric model. The numerical analyses indicate that the tension between the experimental measurement and the standard model prediction is remedied in the $B-L$ supersymmetric model.

    hep-phJHEP(2021)·44 citations
11. 11*

    Interacting quark matter effects on the structure of compact stars

    José C. Jiménez🇧🇷

    In this work, we study the effects that interacting quark matter has on the stellar structure of strange and charm quark stars. Additionally, their stability against radial pulsations is analyzed using a first-order formalism for adiabatic general relativistic oscillations. Besides, the early stage of stellar evolution of neutron stars after the supernovae explosion, i.e. protoneutron stars, is investigated by considering the possibility of a first-order phase transition to quark matter rich in leptons, where the dynamics of conversion between phases is studied within a thermal nucleation model. For each kind of compact star mentioned we use for the quark phase the equation of state calculated within cold perturbative QCD (pQCD), parametrized only by its renormalization scale. We note that the original pQCD framework is manipulated appropriately to include neutrinos and extended to add heavy quarks to the original system composed only by up, down and strange quark flavors.

    hep-phhep-lathep-thnucl-th3 citations
12. 12*

    New physics explanations of $a_{\mu }$ in light of the FNAL muon $g-2$ measurement

    Peter Athron🇨🇳 · Csaba Balázs🇦🇺 · Douglas HJ Jacob🇦🇺 · Wojciech Kotlarski🇩🇪 · Dominik Stöckinger🇩🇪 · Hyejung Stöckinger-Kim🇩🇪

    The Fermilab Muon $g-2$ experiment recently reported its first measurement of the anomalous magnetic moment $a_{\mu }^{\text{FNAL}}$, which is in full agreement with the previous BNL measurement and pushes the world average deviation $\Delta a_{\mu }^{2021}$ from the Standard Model to a significance of $4.2\sigma$. Here we provide an extensive survey of its impact on beyond the Standard Model physics. We use state-of-the-art calculations and a sophisticated set of tools to make predictions for $a_{\mu }$, dark matter and LHC searches in a wide range of simple models with up to three new fields, that represent some of the few ways that large $\Delta a_{\mu }$ can be explained. In addition for the particularly well motivated Minimal Supersymmetric Standard Model, we exhaustively cover the scenarios where large $\Delta a_{\mu }$ can be explained while simultaneously satisfying all relevant data from other experiments. Generally, the $\Delta a_{\mu }$ result can only be explained by rather small masses and/or large couplings and enhanced chirality flips, which can lead to conflicts with limits from LHC and dark matter experiments. Our results show that the new measurement excludes a large number of models and provides crucial constraints on others. Two-Higgs doublet and leptoquark models provide viable explanations of $a_{\mu }$ only in specific versions and in specific parameter ranges. Among all models with up to three fields, only models with chirality enhancements can accommodate $a_{\mu }$ and dark matter simultaneously. The MSSM can simultaneously explain $a_{\mu }$ and dark matter for Bino-like LSP in several coannihilation regions. Allowing under abundance of the dark matter relic density, the Higgsino- and particularly Wino-like LSP scenarios become promising explanations of the $a_{\mu }$ result.

    hep-phJHEP(2021)·305 citations
13. 13*

    Flavor Anomalies Accommodated in A Flavor Gauged Two Higgs Doublet Model

    Junmou Chen🇨🇳 · Qiaoyi Wen🇨🇳 · Fanrong Xu🇨🇳 · Mengchao Zhang🇨🇳

    The $3.1\sigma$ $R_K$ anomaly after Moriond 2021 and $3.3\sigma$ $\Delta a_{\mu }$ from Fermilab Muon g-2 experiment implicate that the lepton flavor universality violation (LFUV) may play a role in the exploration of new physics. A Flavor Gauged Two-Higgs Doublet Model (FG2HDM) is proposed and investigated in this work. To get rid of the the redundancy in Yukawa coupling of 2HDM-III, a specific U(1) flavor symmetry is introduced. The charge difference between two scalar doublet forbid the appearance of pseudoscalar and hence there are only three particles (a charged and neutral heavy scalar together with a neutral gauge boson) adding to SM particle spectrum. The heavy neutral scalar-mediated flavor-changing interactions occur among down-type quarks. With obvious difference from 2HDM-II, the charged Higgs in FG2HDM can naturally explain $R_{D^{(\ast )}}$ anomaly. The heavy neutral vector boson $Z^{\prime }$, changing flavor for down-type quark uniquely as well, provides a solution to $R_{K^{(\ast )}}$. The anomalous magnetic dipole moment (AMDM) of muon and electron, especially the new released $\Delta a_{\mu }$, can further discriminate $Z^{\prime }$ parameter space.

    hep-phhep-ex18 citations
14. 14*

    Leptophilic bosons and muon g-2 at lepton colliders

    Eung Jin Chun🇰🇷 · Tanmoy Mondal🇰🇷

    A light leptophilic boson (scalar or pseudoscalar) has been postulated to explain the muon g-2 anomaly and could be a portal to dark matter. Realizing the leptophilic nature of a singlet boson in the framework of the two-Higgs-doublet-Model of type-X, we identify the parameter space viable for the explanation of the updated muon g-2 discrepancy. It is then shown that such a hypothetical particle will be unambiguously ruled out or discovered via the Yukawa process at a lepton collider designed as a Higgs factory.

    hep-phhep-exJHEP(2021)·34 citations
15. 15*

    $(\mathbf{g}-2{)}_{\mathbf{e},\mathbf{\mu }}$ in an extended inverse type-III seesaw

    Pablo Escribano🇪🇸 · Jorge Terol-Calvo🇪🇸 · Avelino Vicente🇪🇸

    There has been a long-standing discrepancy between the experimental measurements of the electron and muon anomalous magnetic moments and their predicted values in the Standard Model. This is particularly relevant in the case of the muon $g-2$, which has attracted a remarkable interest in the community after the long-awaited announcement of the first results by the Muon $g-2$ collaboration at Fermilab, which confirms a previous measurement by the E821 experiment at Brookhaven and enlarges the statistical significance of the discrepancy, now at $4.2\sigma$. In this paper we consider an extension of the inverse type-III seesaw with a pair of vector-like leptons that induces masses for neutrinos at the electroweak scale and show that one can accommodate the electron and muon anomalous magnetic moments, while being compatible with all relevant experimental constraints.

    hep-phPRD(2021)·52 citations
16. 16*

    Distribution of supersymmetry mu parameter and Peccei-Quinn scale f_a from the landscape

    Howard Baer🇺🇸 · Vernon Barger🇺🇸 · Dibyashree Sengupta🇹🇼 · Robert Wiley Deal🇺🇸

    A scan of soft SUSY breaking parameters within the string theory landscape with the MSSM assumed as the low energy effective field theory -- using a power-law draw to large soft terms coupled with an anthropic selection of a derived weak scale to be within a factor four of our measured value -- predicts a peak probability of m_h~125 GeV with sparticles masses typically beyond the reach of LHC Run 2. Such multiverse simulations usually assume a fixed value of the SUSY conserving superpotential mu parameter to be within the assumed anthropic range, mu<~ 350 GeV. However, depending on the assumed solution to the SUSY mu problem, the expected mu term distribution can actually be derived. In this paper, we examine two solutions to the SUSY mu problem. The first is the gravity-safe-Peccei-Quinn (GSPQ) model based on an assumed Z_{24}^R discrete R-symmetry which allows a gravity-safe accidental, approximate Peccei-Quinn global symmetry to emerge which also solves the strong CP problem. The second case is the Giudice-Masiero solution wherein the mu term effectively acts as a soft term and has a linear draw to large values. For the first case, we also present the expected landscape distribution for the PQ scale f_a; in this case, weak scale anthropics limits its range to the cosmological sweet zone of around f_a~ 10^{11} GeV.

    hep-phhep-thPRD(2021)·9 citations
17. 17*

    Inclusive production of heavy quarkonium ${\eta }_Q$ via $Z$ boson decays within the framework of nonrelativistic QCD

    Xu-Chang Zheng🇨🇳 · Chao-Hsi Chang🇨🇳 · Xing-Gang Wu🇨🇳 · Xu-Dong Huang🇨🇳 · Guang-Yu Wang🇨🇳

    In the paper, the inclusive production of heavy quarkonium ${\eta }_Q$ ($Q=b$ or $c$) via $Z$ boson decays within the framework of nonrelativistic QCD effective theory are studied. The contributions from the leading color-singlet and color-octet Fock states are considered. Total and differential decay widths for the inclusive decays $Z\to {\eta }_Q+X$ are presented. It is found that the decays $Z\to {\eta }_Q+X$ are dominated by the ${}^3{S}_1^{[8]}$ component, so the decays can be inversely adopted to determine the values of the long-distance matrix elements $⟨{\mathcal{O}}^{{\eta }_c}{(}^3{S}_1^{[8]})⟩$ and $⟨{\mathcal{O}}^{{\eta }_b}{(}^3{S}_1^{[8]})⟩$, respectively. Our numerical results show that at an $e^{+}{e}^{-}$ collider running at the $Z$ pole with a high luminosity around $10^{35}{\mathrm{cm}}^{-2}{\mathrm{s}}^{-1}$ (a super $Z$ factory), there are about $4.5\times 10^7$ ${\eta }_c$ meson events and $6.1\times 10^5$ ${\eta }_b$ meson events to be produced per operation year, and the inclusive decays may be used for clarifying some problems on the heavy quarkonium ${\eta }_Q$ and nonrelativistic QCD.

    hep-phPRD(2021)·3 citations
18. 18*

    The deconvolution problem of deeply virtual Compton scattering

    V. Bertone🇫🇷 · H. Dutrieux🇫🇷 · C. Mezrag🇫🇷 · H. Moutarde🇫🇷 · P. Sznajder🇵🇱

    Generalised parton distributions are instrumental to study both the three-dimensional structure and the energy-momentum tensor of the nucleon, and motivate numerous experimental programmes involving hard exclusive measurements. Based on a next-to-leading order analysis and a careful study of evolution effects, we exhibit non-trivial generalised parton distributions with arbitrarily small imprints on deeply virtual Compton scattering observables. This means that in practice the reconstruction of generalised parton distributions from measurements, known as the deconvolution problem, does not possess a unique solution for this channel. In this Letter we discuss the consequences on the extraction of generalised parton distributions from data and advocate for a multi-channel analysis.

    hep-phhep-exhep-latnucl-ex+1PRD(2021)·92 citations
19. 19*

    What Fermilab $(g-2{)}_{\mu }$ experiment tells us about discovering SUSY at HL-LHC and HE-LHC

    Amin Aboubrahim🇩🇪 · Michael Klasen🇩🇪 · Pran Nath🇺🇸

    Using an artificial neutral network we explore the parameter space of supergravity grand unified models consistent with the combined Fermilab E989 and Brookhaven E821 data on $(g-2{)}_{\mu }$. The analysis indicates that the region favored by the data is the one generated by gluino-driven radiative breaking of the electroweak symmetry. This region naturally leads to a split sparticle spectrum with light sleptons and weakinos but heavy squarks, with the stau and the chargino as the lightest charged particles. We show that if the entire deviation from the standard model $(g-2{)}_{\mu }$ arises from supersymmetry, then supersymmetry is discoverable at HL-LHC and HE-LHC via production and decay of sleptons within the optimal integrated luminosity of HL-LHC and with a smaller integrated luminosity at HE-LHC.

    hep-phPRD(2021)·58 citations
20. 20*

    Inclusive production of fully-charmed $1^{+-}$ tetraquark at $\mathbf{B}$ factory

    Yingsheng Huang🇨🇳 · Feng Feng🇨🇳 · Yu Jia🇨🇳 · Wen-Long Sang🇨🇳 · De-Shan Yang🇨🇳 · Jia-Yue Zhang🇨🇳

    Inspired by the recent discovery of the $X(6900)$ meson at {\tt LHCb} experiment, we investigate the inclusive production rate of the $C$-odd fully-charmed tetraquarks associated with light hadrons at the $B$ factory within the nonrelativistic QCD (NRQCD) factorization framework. The short-distance coefficient is computed at lowest order in velocity and ${\alpha }_s$. Employing the diquark-antidiquark model to roughly estimate the long-distance NRQCD matrix elements, we predict the rate for inclusive production of the $1^{+-}$ $T_{4c}$ state and discuss the observation prospects at {\tt Belle 2} experiment.

    hep-phhep-exCPC(2021)·25 citations
21. 21*

    Axion-like particles resolve the $B\to \pi K$ and g-2 anomalies

    Bhubanjyoti Bhattacharya🇺🇸 · Alakabha Datta🇺🇸 · Danny Marfatia🇺🇸 · Soumitra Nandi🇮🇳 · John Waite🇺🇸

    We offer a new solution to an old puzzle in the penguin-dominated $B\to \pi K$ decays. The puzzle is the inconsistency among the measurements of the branching ratios and CP asymmetries of the four $B\to \pi K$ decays: $B^{+}\to {\pi }^{+}{K}^0$, $B^{+}\to {\pi }^0{K}^{+}$, $B_d^0\to {\pi }^{-}{K}^{+}$, $B_d^0\to {\pi }^0{K}^0$. We solve the $B\to \pi K$ puzzle by considering the effect of an axion-like particle (ALP) that mixes with the ${\pi }^0$ and has mass close to the ${\pi }^0$ mass. We show that the ALP can also explain the anomalies in the electron and muon anomalous magnetic moments.

    hep-phhep-exPRD(2021)·24 citations
22. 22*

    Exotic to standard bottomonium transitions

    Jaume Tarrús Castellà🇪🇸 · Emilie Passemar🇺🇸

    We study the transition widths of ${\rm Y}(10753)$ and ${\rm Y}(11020)$ into standard bottomonium under the hypothesis that they correspond to the two lowest laying $1^{--}$ hybrid bottomonium states. We employ weakly coupled potential NRQCD an effective filed theory incorporating the heavy quark and multipole expansions. We consider the transitions generated by the leading order and next-to-leading order singlet-octet operators. In the multipole expansion the heavy quark matrix elements factorize from the production of light-quark mesons by gluonic operators. For the leading order operator we compute the widths with a single ${\pi }^0$, $\eta$ or ${\eta }^{\prime }$ in the final state and for the next-to-leading operator for ${\pi }^{+}{\pi }^{-}$ or $K^{+}{K}^{-}$. The hadronization of the gluonic operators is obtained, in the first case, from the axial anomaly and a standard ${\pi }^0-\eta -{\eta }^{\prime }$ mixing scheme and, in the second case, we employ a coupled-channel dispersive representation matched to chiral perturbation theory for both the $S$ and $D$ wave pieces of the gluonic operator. We compare with experimental values and semi-inclusive widths. Our results strongly suggest that ${\rm Y}(11020)$ is indeed a hybrid bottomonium state.

    hep-phPRD(2021)·51 citations
23. 23*

    Small Field Polynomial Inflation: Reheating, Radiative Stability and Lower Bound

    Manuel Drees🇩🇪 · Yong Xu🇩🇪

    We revisit the renormalizable polynomial inflection point model of inflation, focusing on the small field scenario which can be treated fully analytically. In particular, the running of the spectral index is predicted to be $\alpha =-1.43\times 10^{-3}+5.56\times 10^{-5}\left(N_{\mathrm{CMB}}-65\right)$, which might be tested in future. We also analyze reheating through perturbative inflaton decays to either fermionic or bosonic final states via a trilinear coupling. The lower bound on the reheating temperature from successful Big Bang nucleosynthesis gives lower bounds for these couplings; on the other hand radiative stability of the inflaton potential leads to upper bounds. In combination this leads to a lower bound on the location ${\varphi }_0$ of the near inflection point, ${\varphi }_0>3\cdot 10^{-5}$ in Planckian units. The Hubble parameter during inflation can be as low as $H_{\inf }\sim 1$ MeV, or as high as $\sim 10^{10}$ GeV. Similarly, the reheating temperature can lie between its lower bound of $\sim 4$ MeV and about $4\cdot 10^8(10^{11})$ GeV for fermionic (bosonic) inflaton decays. We finally speculate on the "prehistory" of the universe in this scenario, which might have included an epoch of eternal inflation.

    hep-phastro-ph.COhep-thJCAP(2021)·59 citations
24. 24*

    Disentangling SMEFT operators with future low-energy PVES experiments

    Radja Boughezal🇺🇸 · Frank Petriello🇺🇸 · Daniel Wiegand🇺🇸

    We study the potential of future Parity-Violating Electron Scattering (PVES) data to probe the parameter space of the Standard Model Effective Field Theory (SMEFT). We contrast the constraints derived from Drell-Yan data taken at the Large Hadron Collider (LHC) with projections of the planned PVES experiments SoLID and P2. We show that the PVES data can complement the bounds set by the LHC data in the dimension-6 operator space since it probes different combinations of operators than Drell-Yan. The lower characteristic energy of P2 and SoLID also helps disentangle effects of dimension-6 and dimension-8 operators that are difficult to resolve with LHC Drell-Yan data alone.

    hep-phPRD(2021)·31 citations
25. 25*

    The signature of charge dependent directed flow observables by electromagnetic fields in heavy ion collisions

    Yifeng Sun🇮🇹 · Vincenzo Greco🇮🇹 · Salvatore Plumari🇮🇹

    We discuss the generation of the directed flow $v_1(p_T,y_z)$ induced by the electromagnetic field as a function of $p_T$ and $y_z$. Despite the complex dynamics of charged particles due to strong interactions generating several anisotropies in the azimuthal angle, it is possible at $p_T>m$ to directly correlate the splitting in $v_1$ of heavy quarks with different charges to some main features of the magnetic field, and in particular its values at formation and freeze-out time. We further found that the slope of the splitting $d\Delta v_1/d{y}_z{|}_{y_z=0}$ of positively and negatively charged particles at high $p_T$ can be formulated as $d\Delta v_1/d{y}_z{|}_{y_z=0}=-\alpha \frac{\partial \ln f}{\partial p_T}+\frac{2\alpha -\beta }{p_T}$, where the constants $\alpha$ and $\beta$ are constrained by the $y$ component of magnetic fields and the sign of $\alpha$ is simply determined by the difference $\Delta [t{B}_y(t)]$ in the center of colliding systems at the formation time of particles and at the time when particles leave the effective range of electromagnetic fields or freeze out. The formula is derived from general considerations and is confirmed by several related numerical simulations; it supplies a useful guide to quantify the effect of different magnetic field configurations and provides an evidence of why the measurement of $\Delta v_1$ of charm, bottom and leptons from $Z^0$ decay and their correlations are a powerful probe of the initial e.m. fields in ultra-relativistic collisions.

    ↳ nucl-thhep-phnucl-exEur.Phys.J.Plus(2021)·9 citations
26. 26*

    Slow and Safe Gravitinos

    Emilian Dudas🇫🇷 · Marcos A. G. Garcia🇪🇸 · Yann Mambrini🇫🇷 · Keith A. Olive🇺🇸 · Marco Peloso🇮🇹 · Sarunas Verner🇺🇸

    It has been argued that supergravity models of inflation with vanishing sound speeds, $c_s$, lead to an unbounded growth in the production rate of gravitinos. We consider several models of inflation to delineate the conditions for which $c_s=0$. In models with unconstrained superfields, we argue that the mixing of the goldstino and inflatino in a time-varying background prevents the uncontrolled production of the longitudinal modes. This conclusion is unchanged if there is a nilpotent field associated with supersymmetry breaking with constraint ${\mathbf{S}}^2=0$, i.e. sgoldstino-less models. Models with a second orthogonal constraint, $\mathbf{S}(\mathbf{\Phi }-\bar{\mathbf{\Phi }})=0$, where $\mathbf{\Phi }$ is the inflaton superfield, which eliminates the inflatino, may suffer from the over-production of gravitinos. However, we point out that these models may be problematic if this constraint originates from a UV Lagrangian, as this may require using higher derivative operators. These models may also exhibit other pathologies such as $c_s>1$, which are absent in theories with the single constraint or unconstrained fields.

    ↳ hep-thastro-ph.COhep-phPRD(2021)·28 citations
27. 27*

    Tidal-heating/viscous dissipation correspondence in black holes and viscous compact objects

    Yotam Sherf🇮🇱

    The effect of energy absorption during the binary evolution of Exotic-compact-objects (ECOs) is extensively studied. We review the underlying mechanism that provides the energy dissipation in material objects - tidal friction. We show that unlike typical astrophysical objects, where absorption due to viscosity is negligible, in ECOs, absorption could potentially mimic the analogous effect of black-holes (BHs) - tidal heating. We stand for their differences and similarities in the context of energy dissipation during the inspiral. Inspired by the membrane paradigm and recent studies, we demonstrate how viscosity is a defining feature that quantifies how close is the ECO absorption to that of a classical BH absorption. We show that for ECOs, viscosity can induce significant modifications to the GW waveform, which in some favorable scenarios of super-massive binaries of equal mass and spin, enables the measurement of the ECO absorption in the future precision gravitational-wave (GW) observations. Finally, we discuss the implications on the ECO reflection coefficient and the relation to the universal viscosity to volume entropy bound.

    ↳ gr-qcastro-ph.HEhep-phhep-thPRD(2021)·16 citations
28. 28*

    Effective field theories and inflationary magnetogenesis

    Massimo Giovannini🇨🇭

    The effective approach is applied to the analysis of inflationary magnetogenesis. Rather than assuming a particular underlying description, all the generally covariant terms potentially appearing with four space-time derivatives in the effective action have been included and weighted by inflaton-dependent couplings. The higher derivatives are suppressed by the negative powers of a typical mass scale whose specific values ultimately depend on the tensor to scalar ratio. During a quasi-de Sitter stage the corresponding corrections always lead to an asymmetry between the hypermagnetic and the hyperelectric susceptibilities. After presenting a general method for the estimate of the gauge power spectra, the obtained results are illustrated for generic models and also in the case of some non-generic scenarios where either the inflaton has some extra symmetry or the higher-order terms are potentially dominant.

    ↳ hep-thastro-ph.COgr-qchep-phPLB(2021)·9 citations
29. 29*

    Radiative Classical Gravitational Observables at $\mathcal{O}(G^3)$ from Scattering Amplitudes

    Enrico Herrmann🇺🇸 · Julio Parra-Martinez🇺🇸 · Michael S. Ruf🇩🇪 · Mao Zeng🇬🇧

    We compute classical gravitational observables for the scattering of two spinless black holes in general relativity and $\mathcal{N}=8$ supergravity in the formalism of Kosower, Maybee, and O'Connell (KMOC). We focus on the gravitational impulse with radiation reaction and the radiated momentum in black hole scattering at $\mathcal{O}(G^3)$ to all orders in the velocity. These classical observables require the construction and evaluation of certain loop-level quantities which are greatly simplified by harnessing recent advances from scattering amplitudes and collider physics. In particular, we make use of generalized unitarity to construct the relevant loop integrands, employ reverse unitarity, the method of regions, integration-by-parts (IBP), and (canonical) differential equations to simplify and evaluate all loop and phase-space integrals to obtain the classical gravitational observables of interest to two-loop order. The KMOC formalism naturally incorporates radiation effects which enables us to explore these classical quantities beyond the conservative two-body dynamics. From the impulse and the radiated momentum, we extract the scattering angle and the radiated energy. Finally, we discuss universality of the impulse in the high-energy limit and the relation to the eikonal phase.

    ↳ hep-thgr-qchep-phJHEP(2021)·260 citations
30. 30*

    Primordial Black Holes Arise When The Inflaton Falls

    Keisuke Inomata🇺🇸 · Evan McDonough🇺🇸 · Wayne Hu🇺🇸

    Primordial Black Holes (PBHs) have entered the forefront of theoretical cosmology, due their potential role in phenomena ranging from gravitational waves, to dark matter, to galaxy formation. While producing PBHs from inflationary fluctuations naively would seem to require a large deceleration of the inflaton from its velocity at the horizon exit of CMB scales, in this work we demonstrate that an acceleration from a relatively small downward step in the potential that is transited in much less than an e-fold amplifies fluctuations as well. Depending on the location of the step, such PBHs could explain dark matter or the black holes detected by the gravitational wave interferometers. The perturbation enhancement has a natural interpretation as particle production due to the non-adiabatic transition associated with the step.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2021)·78 citations
31. 31*

    Completing the eclectic flavor scheme of the ${\mathbb{Z}}_2$ orbifold

    Alexander Baur🇩🇪 · Moritz Kade🇩🇪 · Hans Peter Nilles🇩🇪 · Saul Ramos-Sanchez🇲🇽 · Patrick K.S. Vaudrevange🇩🇪

    We present a detailed analysis of the eclectic flavor structure of the two-dimensional ${\mathbb{Z}}_2$ orbifold with its two unconstrained moduli $T$ and $U$ as well as $\mathrm{SL}(2,\mathbb{Z}{)}_T\times \mathrm{SL}(2,\mathbb{Z}{)}_U$ modular symmetry. This provides a thorough understanding of mirror symmetry as well as the $R$-symmetries that appear as a consequence of the automorphy factors of modular transformations. It leads to a complete picture of local flavor unification in the $(T,U)$ modulus landscape. In view of applications towards the flavor structure of particle physics models, we are led to top-down constructions with high predictive power. The first reason is the very limited availability of flavor representations of twisted matter fields as well as their (fixed) modular weights. This is followed by severe restrictions from traditional and (finite) modular flavor symmetries, mirror symmetry, CP and $R$-symmetries on the superpotential and Kaehler potential of the theory.

    ↳ hep-thhep-phJHEP(2021)·29 citations
32. 32*

    Thermal axions with multi-eV masses are possible in low-reheating scenarios

    Pierluca Carenza🇮🇹 · Massimiliano Lattanzi🇮🇹 · Alessandro Mirizzi🇮🇹 · Francesco Forastieri🇮🇹

    We revise cosmological mass bounds on hadronic axions in low-reheating cosmological scenarios, with a reheating temperature $T_{\mathrm{RH}}\le 100$ MeV, in light of the latest cosmological observations. In this situation, the neutrino decoupling would be unaffected, while the thermal axion relic abundance is suppressed. Moreover, axions are colder in low-reheating temperature scenarios, so that bounds on their abundance are possibly loosened. As a consequence of these two facts, cosmological mass limits on axions are relaxed. Using state-of-the-art cosmological data and characterizing axion-pion interactions at the leading order in chiral perturbation theory, we find in the standard case an axion mass bound $m_a<0.26$ eV. However, axions with masses $m_a\simeq 1$ eV, or heavier, would be allowed for reheating temperatures $T_{\mathrm{RH}}\lesssim 80$ MeV. Multi-eV axions would be outside the mass sensitivity of current and planned solar axion helioscopes and would demand new experimental approaches to be detected.

    ↳ astro-ph.COhep-phJCAP(2021)·26 citations
33. 33*

    JefiGPU: Jefimenko's Equations on GPU

    Jun-Jie Zhang🇨🇳 · Jian-Nan Chen🇨🇳 · Guo-Liang Peng🇨🇳 · Tai-Jiao Du🇨🇳 · Hai-Yan Xie🇨🇳

    We have implemented a GPU version of the Jefimenko's equations -- JefiGPU. Given the proper distributions of the source terms $\rho$ (charge density) and $\mathbf{J}$ (current density) in the source volume, the algorithm gives the electromagnetic fields in the observational region (not necessarily overlaps the vicinity of the sources). To verify the accuracy of the GPU implementation, we have compared the obtained results with that of the theoretical ones. Our results show that the deviations of the GPU results from the theoretical ones are around 5\%. Meanwhile, we have also compared the performance of the GPU implementation with a CPU version. The simulation results indicate that the GPU code is significantly faster than the CPU version. Finally, we have studied the parameter dependence of the execution time and memory consumption on one NVIDIA Tesla V100 card. Our code can be consistently coupled to RBG (Relativistic Boltzmann equations on GPUs) and many other GPU-based algorithms in physics.

    ↳ physics.comp-phastro-ph.IMhep-phphysics.geo-phComput.Phys.Commun.(2022)·1 citation

* 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.