Thu·Jul 1, 2021Thursday·July 1, 2021

1. 01*

   Hints of Natural Supersymmetry in Flavor Anomalies?

   P. S. Bhupal Dev🇺🇸 · Amarjit Soni🇺🇸 · Fang Xu🇺🇸

   The recent results from the Fermilab muon $g-2$ experiment, as well as the persisting hints of lepton flavor universality violation in $B$-meson decays, present a very strong case for flavor-nonuniversal new physics beyond the Standard Model. We assert that a minimal $R$-parity violating supersymmetric scenario with relatively light third-generation sfermions (dubbed as 'RPV3') provides a natural, well-motivated framework for the simultaneous explanation of all flavor anomalies, while being consistent with a multitude of low-energy flavor constraints, as well as with limits from high-energy collider searches. We further propose complementary tests and distinct signatures of this scenario in the high-$p_T$ searches at current and future colliders. Specifically, we find that an sbottom in the mass range of 2-12 TeV accounts for $R_{D^{(\ast )}}$ and $R_{K^{(\ast )}}$ flavor anomalies and it only plays a minor role in the $(g-2{)}_{\mu }$ anomaly, whereas a sneutrino with mass between 0.7-1 TeV is the dominant player for $(g-2{)}_{\mu }$. In this context, we propose specific collider signatures of sbottom via its decays to $\overline{t}(t){\mu }^{+}{\mu }^{-}$, and of sneutrino pairs with their decays leading to a highly distinctive and spectacular four-muon final state, which can be used to completely probe the RPV3 parameter space of interest.

   hep-phhep-exPRD(2022)·46 citations
2. 02*

   Degeneracy patterns of chiral companions at finite temperature

   Juan M. Torres-Rincon🇩🇪

   Chiral symmetry represents a fundamental concept lying at the core of particle and nuclear physics. Its spontaneous breaking in vacuum can be exploited to distinguish chiral hadronic partners, whose masses differ. In fact, the features of this breaking serve as guiding principles for the construction of effective approaches of QCD at low energies, e.g., the chiral perturbation theory, the linear sigma model, the (Polyakov)--Nambu--Jona-Lasinio model, etc. At high temperatures/densities chiral symmetry can be restored bringing the chiral partners to be nearly degenerated in mass. At vanishing baryochemical potential, such restoration follows a smooth transition, and the chiral companions reach this degeneration above the transition temperature. In this work I review how different realizations of chiral partner degeneracy arise in different effective theories/models of QCD. I distinguish the cases where the chiral states are either fundamental degrees of freedom or (dynamically-generated) composed states. In particular, I discuss the intriguing case in which chiral symmetry restoration involves more than two chiral partners, recently addressed in the literature.

   hep-phnucl-thSymmetry(2021)·5 citations
3. 03*

   Testing non-standard neutrino interactions in (anti)-electron neutrino disappearance experiments

   Mariano Chaves🇧🇷 · Orlando Luis Goulart Peres🇧🇷 · Pedro Cunha de Holanda🇧🇷

   We search for scalar and tensor non-standard interactions using (anti)-electron neutrino disappearance in oscillation data. We found a slight preference for non-zero CP violation, coming from both tensor and scalar interactions. The preference for CP violation is lead by Daya Bay low-energy data with a significance that reaches $\sim 1.7\sigma$ in the global analysis (and $\sim 2.1\sigma$ when considering only medium baseline reactors data) compared to the standard neutrino oscillation scenario.

   hep-phhep-exJHEP(2023)·11 citations
4. 04*

   Weaving the covariant three-point vertices efficiently

   Seong Youl Choi🇰🇷 · Jae Hoon Jeong🇰🇷

   An efficient algorithm is developed for compactly weaving all the Lorentz covariant three-point vertices in relation to the decay of a massive particle $X$ of mass $m_X$ and spin $J$ into two particles $M_{1,2}$ with equal mass $m$ and spin $s$. The closely-related equivalence between the helicity formalism and the covariant formulation is utilized so as to identify the basic building blocks for constructing the covariant three-point vertex corresponding to each helicity combination explicitly. The massless case with $m=0$ is worked out straightforwardly and the (anti)symmetrization of the three-point vertex required by spin statistics of identical particles is made systematically. It is shown that the off-shell electromagnetic photon coupling to the states $M_1$ and $M_2$ can be accommodated in this framework. The power of the algorithm is demonstrated with a few typical examples with specific $J$ and $s$ values.

   hep-phhep-exhep-thPRD(2021)·5 citations
5. 05*

   Exploring SMEFT Induced Non-Standard Interactions from COHERENT to Neutrino Oscillations

   Yong Du🇨🇳 · Hao-Lin Li🇨🇳 · Jian Tang🇨🇳 · Sampsa Vihonen🇨🇳 · Jiang-Hao Yu🇨🇳

   We investigate the prospects of next-generation neutrino oscillation experiments DUNE, T2HK and JUNO including TAO within Standard Model Effective Field Theory (SMEFT). We also re-interpret COHERENT data in this framework. Considering both charged and neutral current neutrino Non-Standard Interactions (NSIs), we analyse dimension-6 SMEFT operators and derive lower bounds to UV scale $\Lambda$. The most powerful probe is obtained on ${\mathcal{O}}_{{ledq}_{1211}}$ with $\Lambda \gtrsim$ 450 TeV due to the electron neutrino sample in T2HK near detector. We find DUNE and JUNO to be complementary to T2HK in exploring different subsets of SMEFT operators at about 25 TeV. We conclude that near detectors play a significant role in each experiment. We also find COHERENT with CsI and LAr targets to be sensitive to new physics up to $\sim$900 GeV.

   hep-phhep-exPRD(2022)·24 citations
6. 06*

   The NEUT Neutrino Interaction Simulation

   Yoshinari Hayato🇯🇵 · Luke Pickering🇺🇸

   NEUT is a neutrino-nucleus interaction simulation. It can be used to simulate interactions for neutrinos with between 100 MeV and a few TeV of energy. NEUT is also capable of simulating hadron interactions within a nucleus and is used to model nucleon decay and hadron--nucleus interactions for particle propagation in detector simulations. This article describes the range of interactions modelled and how each is implemented.

   hep-phhep-exEur.Phys.J.ST(2021)·210 citations
7. 07*

   Yukawa coupling unification in non-supersymmetric SO(10) models with an intermediate scale

   Abdelhak Djouadi🇪🇸 · Ruiwen Ouyang🇪🇪 · Martti Raidal🇪🇪

   We discuss the possibility of unifying in a simple and economical manner the Yukawa couplings of third generation fermions in a non-supersymmetric SO(10) model with an intermediate symmetry breaking, focusing on two possible patterns with intermediate Pati-Salam and minimal left-right groups. assume a minimal Yukawa sector at high energy, starting with two Higgs bi-doublets at the intermediate scale which then simply reduce to a two Higgs doublet model at the electroweak scale. We first enforce gauge coupling unification at the two-loop level by including the threshold corrections in the renormalisation group running which are generated by the heavy fields that appear at the intermediate symmetry breaking scale. We then study the running of the Yukawa couplings of the top quark, bottom quark and tau lepton at two-loops in these two breaking schemes, when the appropriate matching conditions are imposed. We find that the unification of the third family Yukawa couplings can be achieved while retaining a viable spectrum, provided that the ratio of the vacuum expectation values of the two Higgs doublet fields is large, $\tan \beta \approx 60$.

   hep-phPLB(2022)·3 citations
8. 08*

   Twist-2 relation and sum rule for tensor-polarized parton distribution functions of spin-1 hadrons

   S. Kumano🇯🇵 · Qin-Tao Song🇨🇳

   Sum rules for structure functions and their twist-2 relations have important roles in constraining their magnitudes and $x$ dependencies and in studying higher-twist effects. The Wandzura-Wilczek (WW) relation and the Burkhardt-Cottingham (BC) sum rule are such examples for the polarized structure functions $g_1$ and $g_2$. Recently, new twist-3 and twist-4 parton distribution functions were proposed for spin-1 hadrons, so that it became possible to investigate spin-1 structure functions including higher-twist ones. We show in this work that an analogous twist-2 relation and a sum rule exist for the tensor-polarized parton distribution functions $f_{1LL}$ and $f_{LT}$, where $f_{1LL}$ is a twist-2 function and $f_{LT}$ is a twist-3 one. Namely, the twist-2 part of $f_{LT}$ is expressed by an integral of $f_{1LL}$ (or $b_1$) and the integral of the function $f_{2LT}=(2/3)f_{LT}-f_{1LL}$ over $x$ vanishes. If the parton-model sum rule for $f_{1LL}$ ($b_1$) is applied by assuming vanishing tensor-polarized antiquark distributions, another sum rule also exists for $f_{LT}$ itself. These relations should be valuable for studying tensor-polarized distribution functions of spin-1 hadrons and for separating twist-2 components from higher-twist terms, as the WW relation and BC sum rule have been used for investigating $x$ dependence and higher-twist effects in $g_2$. In deriving these relations, we indicate that four twist-3 multiparton distribution functions $F_{LT}$, $G_{LT}$, $H_{LL}^{\perp }$, and $H_{TT}$ exist for tensor-polarized spin-1 hadrons. These multiparton distribution functions are also interesting to probe multiparton correlations in spin-1 hadrons.

   hep-phhep-exhep-latnucl-thJHEP(2021)·24 citations
9. 09*

   Isospin extrapolation as a method to study inclusive $\bar{B}\to X_s{\ell }^{+}{\ell }^{-}$ decays

   Yasmine Amhis🇫🇷 · Patrick Owen🇨🇭

   A novel approach to reconstruct inclusive $\bar{B}\to X_s{\ell }^{+}{\ell }^{-}$ decays is presented. The method relies on isopsin symmetry to extrapolate the semi-inclusive signature $X_b\to K^{+}{\ell }^{+}{\ell }^{-}X$ to the fully inclusive rate in $B^{+}$ and $B^0$ decays. We investigate the possibility to measure branching fractions and other observables such as lepton universality ratios and $CP$ asymmetries. As a proof of concept, fast simulation is used to compare the $X_b\to K^{+}{\ell }^{+}{\ell }^{-}X$ signature with a fully inclusive approach. Several experimental advantages are seen which have the potential to make measurements of inclusive $\bar{B}\to X_s{\ell }^{+}{\ell }^{-}$ decays tractable at a hadron collider.

   hep-phhep-exEPJC(2022)·7 citations
10. 10*

    Matter Effects on Mass Square Difference for Four Flavor Neutrino Oscillation

    Vivek Kumar Nautiyal🇮🇳 · Bipin Singh Koranga🇮🇳 · Ashish Shrivastava🇮🇳 · Neelam Das🇮🇳

    We consider the matter effects on four flavor neutrino oscillation scheme (3+1). In presence of sterile neutrino, the simplest four flavor neutrino mixing there are six mixing angles and three Dirac CP phases. In this paper, we discuss about the sensitivity of mass square difference effects Delta21, Delta31, and Delta41 in the matter. We find that in presence of sterile neutrino for four flavor mixing framework, only solar mass square difference Delta21 and atmospheric neutrino mass square difference Delta31 change for different values of Dirac phases and energy. There is no change of sterile neutrino mass square differences. In this letter, we study the matter effects on neutrino mass square differences Delta21, Delta31, and Delta41 and calculate the percentage change with respect to the mass square difference in the matter by varying energy for four flavor framework.

    hep-ph1 citation
11. 11*

    Solar wind bremsstrahlung off DM in our solar system

    Gilles Couture🇨🇦

    We consider the possibility that the solar wind emits photons via bremsstrahlung when colliding with Dark Matter (DM) particles within the solar system. To this effect, we calculate the bremsstrahlung spectrum a proton would emit when colliding with a neutral spin-1/2 particle through the exchange of a scalar neutral particle. We assume a speed of 600 km/sec for the solar wind and assume that the speed of the dark matter halo is due to the motion of the sun through the galaxy, which we take as 300 km/sec. We assume a DM density of 0.3 GeV/cm^3 and a solar wind composed primarily of protons with a total rate of ejection mass set at 10^9kg/sec. We use a Monte Carlo technique to let this interaction take place within the solar system and calculate the photon rate an observer would detect on Earth or at the edge of the solar system as a function of photon energy. We find that the rates are in general very small but could be observable in some scenarios at wavelengths in the mm or cm range.

    hep-phPRD(2022)·1 citation
12. 12*

    Parameter dependence and analysis of the 2HDM neutral Higgs boson pair production and decay at future lepton colliders

    Majid Hashemi🇮🇷 · Neda Nowbakht Ghalati🇮🇷

    In this work, we present a study of the neutral Higgs bosons in the two Higgs doublet model (2HDM) in terms of their production processes and decay channels as a function of the model parameters. The analysis is performed for all four types of the 2HDM and the most promising processes and decay channels are identified for each type of the model. Several Higgs boson mass scenarios below and above the threshold of decay to gauge boson pair are introduced and the corresponding categories of final states are analyzed. The event analysis including collider beam spectrum and detector simulation shows that future lepton colliders have the potential to explore regions in the 2HDM parameter space, which have not yet been excluded by LHC, in a few weeks of operation. Final results are presented in terms of the signal distributions on top of the background and 95% CL exclusion and 5$\sigma$ contours based on center of mass energy of $\sqrt{s}$ = 500 GeV at the Compact Linear Collider (CLIC) or International Linear Collider (ILC).

    hep-phPLB(2022)·4 citations
13. 13*

    Uncertainties in the oscillation parameters measurement due to multi-nucleon effects at NO$\nu$A Experiment

    Paramita Deka🇮🇳 · Jaydip Singh🇮🇳 · Neelakshi Sarma🇮🇳 · Kalpana Bora🇮🇳

    In this work, we investigate the role of multi-nucleon (MN) effects (mainly 2p-2h and RPA) on the sensitivity measurement of various neutrino oscillation parameters, in the disappearance channel of NO$\nu$A (USA) experiment. Short-range correlations and detector effects have also been included in the analysis. We use the kinematical method of reconstruction of the incoming neutrino energy, both at the near and far detectors. The extrapolation technique has been used to estimate oscillated events at the far detector. The latest global best fit values of various light neutrino oscillation parameters have been used in the analysis. We find that MN effects increase uncertainty in the measurement of neutrino oscillation parameters, while lower detector efficiency is reflected in more uncertainty. This study can give useful insight into precision studies at long-baseline neutrino experiments in future measurements.

    hep-phNPB(2022)·6 citations
14. 14*

    Inclusive and diffractive dijet photoproduction in ultraperipheral heavy ion collisions at the LHC

    V. Guzey (St. Petersburg, INP)🇷🇺 · M. Klasen (Munster U., ITP)🇩🇪

    We calculate the cross section of inclusive dijet photoproduction in ultraperipheral collisions (UPCs) of heavy ions at the CERN Large Hadron Collider using next-to-leading order perturbative QCD and demonstrate that it provides a good description of the ATLAS data. We study the role of this data in constraining nuclear parton distribution functions (nPDFs) using the Bayesian reweighting technique and find that it can reduce current uncertainties of nPDFs at small $x$ by a factor of 2. We also make predictions for diffractive dijet photoproduction in UPCs and examine its potential to shed light on the disputed mechanism of QCD factorization breaking in diffraction.

    hep-phhep-exnucl-exSciPost Phys.Proc.(2022)·0 citations
15. 15*

    Model-independent test of T violation in neutrino oscillations

    Thomas Schwetz🇩🇪 · Alejandro Segarra🇩🇪

    We propose a method to establish time reversal symmetry violation at future neutrino oscillation experiments in a largely model-independent way. We introduce a general parametrization of flavour transition probabilities which holds under weak assumptions and covers a large class of new-physics scenarios. This can be used to search for the presence of T-odd components in the transition probabilities by comparing data at different baselines but at the same neutrino energies. We show that this test can be performed already with experiments at three different baselines and might be feasible with experiments under preparation/consideration.

    hep-phPRL(2022)·15 citations
16. 16*

    Spin-dependent dark matter-electron interactions

    C.-P. Liu🇹🇼 · Chih-Pan Wu🇨🇦 · Jiunn-Wei Chen🇹🇼 · Hsin-Chang Chi🇹🇼 · Mukesh K. Pandey🇹🇼 · Lakhwinder Singh🇹🇼 · Henry T. Wong🇹🇼

    Detectors with low thresholds for electron recoil open a new window to direct searches of sub-GeV dark matter (DM) candidates. In the past decade, many strong limits on DM-electron interactions have been set, but most on the one which is spin-independent (SI) of both dark matter and electron spins. In this work, we study DM-atom scattering through a spin-dependent (SD) interaction at leading order (LO), using well-benchmarked, state-of-the-art atomic many-body calculations. Exclusion limits on the SD DM-electron cross section are derived with data taken from experiments with xenon and germanium detectors at leading sensitivities. In the DM mass range of 0.1 - 10 GeV, the best limits set by the XENON1T experiment: ${\sigma }_e^{\text{(SD)}}<10^{-41}-10^{-40}{\text{cm}}^2$ are comparable to the ones drawn on DM-neutron and DM-proton at slightly bigger DM masses. The detector's responses to the LO SD and SI interactions are analyzed. In nonrelativistic limit, a constant ratio between them leads to an indistinguishability of the SD and SI recoil energy spectra. Relativistic calculations however show the scaling starts to break down at a few hundreds of eV, where spin-orbit effects become sizable. We discuss the prospects of disentangling the SI and SD components in DM-electron interactions via spectral shape measurements, as well as having spin-sensitive experimental signatures without SI background.

    hep-phhep-exPRD(2022)·15 citations
17. 17*

    Mapping the viable parameter space for testable leptogenesis

    Marco Drewes🇧🇪 · Yannis Georis🇧🇪 · Juraj Klarić🇨🇭

    We for the first time map the range of active-sterile neutrino mixing angles in which leptogenesis is possible in the type I seesaw model with three heavy neutrinos with Majorana masses between 50 MeV and 100 TeV, covering the entire experimentally accessible mass range. Our study includes both,the asymmetry generation during freeze-in (ARS mechanism) and freeze-out (resonant leptotenesis) of the heavy neutrinos. The range of mixings for which leptogenesis is feasible is considerably larger than in the minimal model with only two heavy neutrinos and extends all the way up to the current experimental bounds. For such large mixing angles the HL-LHC could potentially observe a number of events that is large enough to compare different decay channels, a first step towards testing the hypothesis that these particles may be responsible for the origin of matter and neutrino masses.

    hep-phPRL(2022)·94 citations
18. 18*

    $\tau \to \ell +$ invisible through invisible-savvy collider variables

    Diego Guadagnoli🇫🇷 · Chan Beom Park🇰🇷 · Francesco Tenchini🇩🇪

    New particles $\varphi$ in the MeV-GeV range produced at colliders and escaping detection can be searched for at operating $b-$ and $\tau -$factories such as Belle II. A typical search topology involves pair-produced $\tau$s (or mesons), one of which decaying to visibles plus the $\varphi$, and the other providing a tag. One crucial impediment of these searches is the limited ability to reconstruct the parents' separate boosts. This is the case in the 'typical' topology where both decay branches include escaping particles. We observe that such topology lends itself to the use of kinematic variables such as $M_2$, designed for pairwise decays to visibles plus escaping particles, and endowed with a built-in ('MAOS') way to efficiently guess the parents' separate boosts. Starting from this observation, we construct several kinematic quantities able to discriminate signal from background, and apply them to a benchmark search, $\tau \to e+\varphi$, where $\varphi$ can be either an axion-like particle or a hidden photon. Our considered variables can be applied to a wider range of topologies than the current reference technique, based on the event thrust, with which they are nearly uncorrelated. Application of our strategy leads to an improvement by a factor close to 3 in the branching-ratio upper limit for $\tau \to e\varphi$, with respect to the currently expected limit, assuming $m_{\varphi }\lesssim 1$ MeV. For example, we anticipate a sensitivity of $1.7\times 10^{-5}$ with the data collected before the 2022 shutdown.

    hep-phhep-exPLB(2021)·20 citations
19. 19*

    Primordial Black Hole Evaporation and Dark Matter Production: I. Solely Hawking radiation

    Andrew Cheek🇧🇪 · Lucien Heurtier🇬🇧 · Yuber F. Perez-Gonzalez🇺🇸 · Jessica Turner🇬🇧

    Hawking evaporation of black holes in the early Universe is expected to copiously produce all kinds of particles, regardless of their charges under the Standard Model gauge group. For this reason, any fundamental particle, known or otherwise, could be produced during the black hole lifetime. This certainly includes dark matter (DM) particles. This paper improves upon previous calculations of DM production from primordial black holes (PBH) by consistently including the greybody factors, and by meticulously tracking a system of coupled Boltzmann equations. We show that the initial PBH densities required to produce the observed relic abundance depend strongly on the DM spin, varying in about $\sim 2$ orders of magnitude between a spin-2 and a scalar DM in the case of non-rotating PBHs. For Kerr PBHs, we have found that the expected enhancement in the production of bosons reduces the initial fraction needed to explain the measurements. We further consider indirect production of DM by assuming the existence of additional and unstable degrees of freedom emitted by the evaporation, which later decay into the DM. For a minimal setup where there is only one heavy particle, we find that the final relic abundance can be increased by at most a factor of $\sim 4$ for a scalar heavy state and a Schwarzschild PBH, or by a factor of $\sim 4.3$ for a spin-2 particle in the case of a Kerr PBH.

    hep-phastro-ph.COPRD(2022)·172 citations
20. 20*

    Primordial Black Hole Evaporation and Dark Matter Production: II. Interplay with the Freeze-In/Out Mechanism

    Andrew Cheek🇧🇪 · Lucien Heurtier🇬🇧 · Yuber F. Perez-Gonzalez🇺🇸 · Jessica Turner🇬🇧

    We study how the evaporation of primordial black holes (PBHs) can affect the production of dark matter (DM) particles through thermal processes. We consider fermionic DM interacting with Standard Model particles via a spin-1 mediator in the context of a Freeze-Out or Freeze-In mechanism. We show that when PBHs evaporate after dominating the Universe's energy density, PBHs act as a source of DM and continuously inject entropy into the visible sector that can affect the thermal production in three qualitatively different ways. We compute the annihilation cross-sections which account for the interactions between and within the PBH produced and thermally produced DM populations, and establish a set of Boltzmann equations which we solve to obtain the correct relic abundance in those different regimes and confront the results with a set of different cosmological constraints. We provide analytic formulae to calculate the relic abundance for the Freeze-Out and Freeze-In mechanism in a PBH dominated early Universe. We identify regions of the parameter space where the PBHs dilute the relic density and thermalization occurs. Furthermore, we have made our code that numerically solves the Boltzmann equations publicly available.

    hep-phastro-ph.COPRD(2022)·115 citations
21. 21*

    Radiative corrections for factorized jet observables in heavy ion collisions

    Varun Vaidya🇺🇸

    I look at the renormalization of the medium structure function and a medium induced jet function in a factorized cross section for jet substructure observables in Heavy Ion collisions. This is based on the formalism developed in \cite{Vaidya:2020lih}, which uses an Open quantum system approach combined with the Effective Field Theory(EFT) for forward scattering to derive a factorization formula for jet observables which work as hard probes of a long lived dilute Quark Gluon Plasma(QGP) medium. I show that the universal medium structure function that captures the observable independent physics of the QGP has both UV and rapidity anomalous dimensions that appear due to medium induced Bremsstrahlung. The resulting Renormalization Group(RG) equations correspond to the BFKL equation and the running of the QCD coupling respectively. I present the first results for the numerical impact of resummation using these RG equations on the mean free path of the jet in the medium. I also briefly discuss the prospects of extending this formalism for a short lived dense medium.

    hep-phnucl-thJHEP(2024)·14 citations
22. 22*

    The GAMBIT Universal Model Machine: from Lagrangians to Likelihoods

    Sanjay Bloor🇬🇧 · Tomás E. Gonzalo🇦🇺 · Pat Scott🇬🇧 · Christopher Chang🇦🇺 · Are Raklev🇳🇴 · José Eliel Camargo-Molina🇸🇪 · Anders Kvellestad🇳🇴 · Janina J. Renk🇬🇧 · Peter Athron🇨🇳 · Csaba Balázs🇦🇺

    We introduce the GAMBIT Universal Model Machine (GUM), a tool for automatically generating code for the global fitting software framework GAMBIT, based on Lagrangian-level inputs. GUM accepts models written symbolically in FeynRules and SARAH formats, and can use either tool along with MadGraph and CalcHEP to generate GAMBIT model, collider, dark matter, decay and spectrum code, as well as GAMBIT interfaces to corresponding versions of SPheno, micrOMEGAs, Pythia and Vevacious (C++). In this paper we describe the features, methods, usage, pathways, assumptions and current limitations of GUM. We also give a fully worked example, consisting of the addition of a Majorana fermion simplified dark matter model with a scalar mediator to GAMBIT via GUM, and carry out a corresponding fit.

    hep-phEPJC(2021)·28 citations
23. 23*

    Measurements of the Hubble Constant: Tensions in Perspective

    Wendy L. Freedman🇺🇸

    Measurement of the distances to nearby galaxies have improved rapidly in recent decades. The ever-present challenge is to reduce systematic effects, especially as greater distances are probed, and the uncertainties become larger. In this paper, we combine several recent calibrations of the Tip of the Red Giant Branch (TRGB) method. These calibrations are internally self-consistent at the 1% level. New Gaia Early Data Release 3 (EDR3) data provide an additional consistency check, at a (lower) 5% level of accuracy, a result of the well-documented Gaia angular covariance bias. The updated TRGB calibration applied to a distant sample of Type Ia supernovae from the Carnegie Supernova Project results in a value of the Hubble constant of Ho = 69.8 $\pm$ 0.6 (stat) $\pm$ 1.6 (sys) km/s/Mpc. No statistically significant difference is found between the value of Ho based on the TRGB and that determined from measurements of the cosmic microwave background. The TRGB results are also consistent to within 2$\sigma$ with the SHoES and Spitzer plus HST Key Project Cepheid calibrations. The TRGB results alone do not demand additional new physics beyond the standard Lambda-CDM cosmological model. They have the advantage of simplicity of the underlying physics (the core He flash) and small systematic uncertainties (from extinction, metallicity and crowding). Finally, the strengths and weaknesses of both the TRGB and Cepheids are reviewed, and prospects for addressing the current discrepancy with future Gaia, HST and JWST observations are discussed. Resolving this discrepancy is essential for ascertaining if the claimed tension in Ho between the locally-measured and the CMB-inferred value is physically motivated.

    ↳ astro-ph.COhep-phhep-thApJ(2021)·616 citations
24. 24*

    Flavor decomposition of the nucleon unpolarized, helicity and transversity parton distribution functions from lattice QCD simulations

    Constantia Alexandrou (Univ. of Cyprus and The Cyprus Inst.)🇨🇾 · Martha Constantinou (Temple Univ.)🇺🇸 · Kyriakos Hadjiyiannakou (Univ. of Cyprus and The Cyprus Inst.)🇨🇾 · Karl Jansen (DESY-Zeuthen)🇩🇪 · Floriano Manigrasso (Univ. of Cyprus, Humboldt Univ. of Berlin and Univ. of Rome Tor Vergata)🇨🇾

    We present results on the quark unpolarized, helicity and transversity parton distributions functions of the nucleon. We use the quasi-parton distribution approach within the lattice QCD framework and perform the computation using an ensemble of twisted mass fermions with the strange and charm quark masses tuned to approximately their physical values and light quark masses giving pion mass of 260 MeV. We use hierarchical probing to evaluate the disconnected quark loops. We discuss identification of ground state dominance, the Fourier transform procedure and convergence with the momentum boost. We find non-zero results for the disconnected isoscalar and strange quark distributions. The determination of the quark parton distribution and in particular the strange quark contributions that are poorly known provide valuable input to the structure of the nucleon.

    ↳ hep-lathep-phnucl-thPRD(2021)·66 citations
25. 25*

    General-relativistic treatment of tidal $g$-mode resonances in coalescing binaries of neutron stars. I. Theoretical framework and crust breaking

    Hao-Jui Kuan🇩🇪 · Arthur G. Suvorov🇩🇪 · Kostas D. Kokkotas🇩🇪

    During the final stages of a neutron-star binary coalescence, stellar quasi-normal modes can become resonantly excited by tidal fields. If the strain exerted by the excited modes exceeds the extent to which the crust can respond linearly, localised crustal failures may occur. In this work, we re-examine resonant $g$-mode excitations of relativistic neutron stars in the last $\sim$ 10 seconds of an inspiral. We adopt realistic equations of state that pass constraints from GW170817, include 3rd order post-Newtonian terms for the conservation orbital motion, and employ a 2.5 post-Newtonian scheme for gravitational back-reaction. Frequency modulations of the modes due to tidal fields, Lorentz forces, and (slow) rotation are also considered to investigate the maximal strain achievable by resonantly-excited $g$-modes. Depending on the equation of state, degree of stratification, and stellar magnetic field, we find that certain $g$-modes excitations may be able to break the crust some seconds prior to coalescence.

    ↳ gr-qchep-phMNRAS(2021)·43 citations
26. 26*

    Merger of a Neutron Star with a Black Hole: one-family vs. two-families scenario

    Francesco Di Clemente (Ferrara University and INFN Sez. Ferrara)🇮🇹 · Alessandro Drago (Ferrara University and INFN Sez. Ferrara)🇮🇹 · Giuseppe Pagliara (Ferrara University and INFN Sez. Ferrara)🇮🇹

    A kilonova signal is generally expected after a Black Hole - Neutron Star merger. The strength of the signal is related to the equation of state of neutron star matter and it increases with the stiffness of the latter. The recent results obtained by NICER from the analyses of PSR J0740+6620 suggest a rather stiff equation of state and the expected kilonova signal is therefore strong, at least if the mass of the Black Hole does not exceed $\sim 10{\mathrm{M}}_{\odot }$ and if the adimensional spin parameter is not too small and the orbit is prograde. We compare the predictions obtained by considering equations of state of neutron star matter satisfying the most recent observations and assuming that only one family of compact stars exists with the results predicted in the two-families scenario. In the latter a soft hadronic equation of state produces very compact stellar objects while a rather stiff quark matter equation of state produces massive strange quark stars, satisfying NICER results. The expected kilonova signal in the two-families scenario is very weak: in particular the Hadronic Star - Black Hole merger produces a much weaker signal than in the one-family scenario because the hadronic equation of state is very soft. Moreover, according to the only existing simulation, the Strange Quark Star - Black Hole merger does not produce a kilonova signal because the amount of mass ejected is negligible. These predictions will be easily tested with the new generation of detectors if Black Holes with an adimensional spin parameter ${\chi }_{\mathrm{BH}}\gtrsim 0.2$ or a mass ${\mathrm{M}}_{\mathrm{BH}}\lesssim 4{\mathrm{M}}_{\odot }$ can be present in the merger.

    ↳ astro-ph.HEhep-phnucl-thApJ(2022)·9 citations
27. 27*

    A Generalised Self-Duality for the Yang-Mills-Higgs System

    L. A. Ferreira🇧🇷 · H. Malavazzi🇧🇷

    Self-duality is a very important concept in the study and applications of topological solitons in many areas of Physics. The rich mathematical structures underlying it lead, in many cases, to the development of exact and non-perturbative methods. We present a generalization of the Yang-Mills-Higgs system by the introduction of scalar fields assembled in a symmetric and invertible matrix h of the same dimension as the gauge group. The coupling of such new fields to the gauge and Higgs fields is made by replacing the Killing form, in the contraction of the group indices, by the matrix h in the kinetic term for the gauge fields, and by its inverse in the Higgs field kinetic term. The theory is conformally invariant in the three dimensional space R^3. An important aspect of the model is that for practically all configurations of the gauge and Higgs fields the new scalar fields adjust themselves to solve the modified self-duality equations. We construct solutions using a spherically symmetric ansätz and show that the 't Hooft-Polyakov monopole becomes a self-dual solution of such modified Yang-Mills-Higgs system. We use an ansätz based on the conformal symmetry to construct vacuum solutions presenting non-trivial toroidal magnetic fields.

    ↳ hep-thhep-phmath-phmath.MP+1PRD(2021)·5 citations
28. 28*

    Infrared propagators of Yang-Mills-Chern-Simons theories in linear covariant gauges

    Luigi C. Ferreira🇧🇷 · Diego R. Granado🇻🇳 · Igor F. Justo🇧🇷 · Antonio D. Pereira🇧🇷

    Recent works have explored non-perturbative effects due to the existence of (infinitesimal) Gribov copies in Yang-Mills-Chern-Simons theories in three Euclidean dimensions. In particular, the removal of such copies modify the gauge field propagator by a self-consistent dynamically generated mass parameter, the Gribov parameter. Due to the interplay with the topological mass introduced by the Chern-Simons term, the propagator features a non-trivial set of phases with poles of different nature, leading to the possible interpretation of a confinfing to deconfining phase transition. Inhere, we restore the BRST symmetry which is softly broken by the elimination of gauge copies and provide a BRST-invariant discussion of such a transition. In order to make clear all physical statements, we deal with linear covariant gauges which contain a gauge parameter and therefore allow for an explicit check of gauge parameter independence of physical results. We also discuss the generation of condensates due to the infrared relevance of infinitesimal Gribov copies.

    ↳ hep-thhep-lathep-phPRD(2021)·3 citations
29. 29*

    Gauge Enhanced Quantum Criticality Beyond the Standard Model

    Juven Wang🇺🇸 · Yi-Zhuang You🇺🇸

    Standard lore views our 4d quantum vacuum governed by one of the candidate Standard Models (SMs), while lifting towards some Grand Unification-like structure (GUT) at higher energy scales. In contrast, in our work, we introduce an alternative view that the SM arises from various neighbor vacua competition in a quantum phase diagram. In general, we regard the SM arising near the gapless quantum criticality (either critical points or critical regions) between the competing neighbor vacua. In particular, we demonstrate how the $su(3)\times su(2)\times u(1)$ SM with 16n Weyl fermions arises near the quantum criticality between the GUT competition of Georgi-Glashow (GG) $su(5)$ and Pati-Salam (PS) $su(4)\times su(2)\times su(2)$. We propose two enveloping toy models. Model I is a conventional $so(10)$ GUT with a Spin(10) gauge group plus GUT-Higgs potential inducing various Higgs transitions. Model II modifies Model I plus a 4d discrete torsion Wess-Zumino-Witten-like term built from GUT-Higgs field (that matches a nonperturbative global mixed gauge-gravity anomaly captured by a 5d invertible topological field theory $w_2{w}_3$), which manifests a Beyond-Landau-Ginzburg criticality between GG and PS models, with extra Beyond-the-Standard-Model (BSM) excitations emerging near a quantum critical region. If the internal symmetries were treated as global symmetries, we show a gapless 4d deconfined quantum criticality with new BSM fractionalized fragmentary excitations of Color-Flavor separation, and gauge enhancement including a Dark Gauge force sector, altogether requiring a double fermionic Spin structure named DSpin. If the internal symmetries are dynamically gauged, we show a 4d boundary criticality such that only appropriately gauge enhanced dynamical GUT gauge fields propagate into an extra-dimensional 5d bulk. The phenomena may be regarded as SM deformation or morphogenesis.

    ↳ hep-thcond-mat.str-elhep-lathep-phPRD(2022)·28 citations
30. 30*

    Scalar Fields Near Compact Objects: Resummation versus UV Completion

    Anne-Christine Davis🇬🇧 · Scott Melville🇬🇧

    Low-energy effective field theories containing a light scalar field are used extensively in cosmology, but often there is a tension between embedding such theories in a healthy UV completion and achieving a phenomenologically viable screening mechanism in the IR. Here, we identify the range of interaction couplings which allow for a smooth resummation of classical non-linearities (necessary for kinetic/Vainshtein-type screening), and compare this with the range allowed by unitarity, causality and locality in the underlying UV theory. The latter region is identified using positivity bounds on the $2\to 2$ scattering amplitude, and in particular by considering scattering about a non-trivial background for the scalar we are able to place constraints on interactions at all orders in the field (beyond quartic order). We identify two classes of theories can both exhibit screening and satisfy existing positivity bounds, namely scalar-tensor theories of $P(X)$ or quartic Horndeski type in which the leading interaction contains an odd power of $X$. Finally, for the quartic DBI Galileon (equivalent to a disformally coupled scalar in the Einstein frame), the analogous resummation can be performed near two-body systems and imposing positivity constraints introduces a non-perturbative ambiguity in the screened scalar profile. These results will guide future searches for UV complete models which exhibit screening of fifth forces in the IR.

    ↳ gr-qcastro-ph.COhep-phhep-thJCAP(2021)·27 citations
31. 31*

    Quantum dots as a probe of fundamental physics: Deviation from exponential decay law

    A.Yoshimi🇯🇵 · M.Tanaka🇯🇵 · M.Yoshimura🇯🇵

    We explore a possibility of measuring deviation from the exponential decay law in pure quantum systems. The power law behavior at late times of decay time profile is predicted in quantum mechanics, and has been experimentally attempted to detect, but with failures except a claim in an open system. It is found that electron tunneling from resonance state confined in man-made atoms, quantum dots, has a good chance of detecting the deviation and testing theoretical predictions. How initial unstable state is prepared influences greatly the time profile of decay law, and this can be used to set the onset time of the power law at earlier times. Comparison with similar process of nuclear alpha decay to discover the deviation is discussed, to explain why there exists a difficulty in this case.

    ↳ quant-phcond-mat.mes-hallhep-exhep-ph+2Eur.Phys.J.D(2022)·2 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.