Fri·Nov 15, 2019Friday·November 15, 2019

1. 01*

   Pseudovector and pseudoscalar spin-dependent interactions in atoms

   Pavel Fadeev🇩🇪 · Filip Ficek🇵🇱 · Mikhail G. Kozlov🇷🇺 · Dmitry Budker🇩🇪 · Victor V. Flambaum🇦🇺

   Hitherto unknown elementary particles can be searched for with atomic spectroscopy. We conduct such a search using a potential that results from the longitudinal polarization of a pseudovector particle. We show that such a potential, inversely proportional to the boson's mass squared, $V\propto 1/M^2$, can stay finite at $M\to 0$ if the theory is renormalizable. We also look for a pseudoscalar boson, which induces a contact spin-dependent potential that does not contribute to new forces searched for in experiments with macroscopic objects, but may be seen in atomic spectroscopy. We extract limits on the interaction constants of these potentials from the experimental spectra of antiprotonic helium, muonium, positronium, helium, and hydrogen.

   hep-phphysics.atom-phPhys. Rev. A 105, 022812 (2022)·2 citations
2. 02*

   On dispersion relations and hadronic light-by-light scattering contribution to the muon anomalous magnetic moment

   Kirill Melnikov🇩🇪 · Arkady Vainshtein🇺🇸

   We discuss the use of dispersion relations for the evaluation of the pseudoscalar contributions to the muon anomalous magnetic moment. We point out that, in the absence of experimental data, reconstruction of light-by-light scattering amplitudes from their absorptive parts is ambiguous and requires additional theoretical input. The need for an additional input makes dispersive computations of the hadronic light-by-light scattering contribution to g-2 akin to phenomenological models, in spite of pretense to the contrary. In particular, we argue that the recent proposal [1], based on the dispersive approach, satisfies short distance constraints at the expense of unjustifiably large deviations from the chiral limit.

   hep-ph21 citations
3. 03*

   Exclusive quarkonium production or decay in soft gluon factorization

   Rong Li🇨🇳 · Yu Feng🇨🇳 · Yan-Qing Ma🇨🇳

   In this paper, we study the application of the recently proposed soft gluon factorization (SGF) to exclusive quarkonium production or decay. We find that in the nonrelativistic QCD factorization framework there are too many nonperturbative parameters. Thanks to the factorization of kinematical physics from dynamical physics, the SGF significantly reduces the number of nonperturbative parameters. Therefore, the SGF can improve our predictive power of exclusive quarkonium production or decay. By applying to ${\eta }_c+\gamma$ production at B-factories, our result is the closest one to data among all theoretical calculations.

   hep-phJHEP(2020)·16 citations
4. 04*

   From Peccei Quinn symmetry to mass hierarchy problem

   Y. A. Garnica · S.F. Mantilla · R. Martinez

   We propose a non-universal $\mathrm{U}(1{)}_X$ gauge extension to the Standard Model (SM) and an additional Peccei-Quinn (PQ) global symmetry to study the mass hierarchy and strong CP problem. The scheme allows us to distinguish among fermion families and to generate the fermionic mass spectrum of particles of the SM. The symmetry breaking is performed by two scalar Higgs doublets and two scalar Higgs singlets, where one of these has the axion which turns out to be a candidate for Cold Dark Matter. The exotic sector is composed by one up-like $T$ and two down-like $J^{1,2}$ heavy quarks, two heavy charged leptons $E,\mathcal{E}$, one additional right-handed neutrino per family ${\nu }_R^{e,\mu ,\tau }$, and an invisible axion $a$. In addition, the large energy scale associated to the breaking of the PQ-symmetry gives masses to the right-handed neutrinos in such a way that the active neutrinos acquire eV-mass values due to the see-saw mechanism. On the other hand, from the non-linear effective Lagrangian, the flavour changing of the down quarks and charged leptons with the axion are considered.

   hep-phJ.Phys.G(2021)·5 citations
5. 05*

   Domain structures and quark potentials in SU($3$) gauge theory

   Seyed Mohsen Hosseini Nejad (Semnan University)🇮🇷

   We analyze the static potentials for various representations in SU($3$) Yang-Mills theory within the framework of the domain model of center vortices. The influence of vortex interactions is investigated on the static potentials. We show that, by ad-hoc choosing the probability weights of the different vortex configurations contributing to the static potential, a phenomenologically satisfactory result for the different representations can be achieved. In particular including vacuum domains, a way to effectively parametrize vortex interactions, is crucial in obtaining an (almost) everywhere convex potential when interpolating between the short distances and the asymptotic regimes.

   hep-phPRD(2019)·3 citations
6. 06*

   Strong First Order Electroweak Phase Transition in Gauge-Higgs Unification at Finite Temperature

   Yuki Adachi · Nobuhito Maru

   We analyze the electroweak phase transition at finite temperature in a model of gauge-Higgs unification where the fermion mass hierarchy including top quark mass, a viable electroweak symmetry breaking and an observed Higgs mass are successfully reproduced. To study the phase transition, we derive the general formula of the 1-loop effective potential at finite temperature by using the $\zeta$ function regularization method. It is remarkable that the functions determining the Kaluza-Klein mass spectrum have only to be necessary in calculations. This potential can be applicable to any higher dimensional theory in flat space where one extra spatial dimension is compactified. Applying to our model of gauge-Higgs unification, the strong first phase transition compatible with 125 GeV Higgs mass is found to happen.

   hep-phhep-thPRD(2020)·4 citations
7. 07*

   The $tZH$ and $tZh$ production in 2HDM: Prospects for discovery at the LHC

   Wei-Shu Hou🇹🇼 · Tanmoy Modak🇹🇼

   We study the discovery potential of the $cg\to tA\to tZH$ process at the LHC, where $A$ and $H$ are CP-odd and even exotic scalars, respectively. The context is the general Two Higgs Doublet Model, where $cg\to tA$ is induced by the flavor changing neutral Higgs coupling ${\rho }_{tc}$. We find that the process $cg\to tA\to tZH$ can be discovered for $m_A\sim 400$ GeV, but would likely require high luminosity running of the LHC. Such a discovery would shed light on the mechanism behind the observed Baryon Asymmetry of the Universe. We also study $cg\to tA\to tZh$, where $h$ is the observed 125 GeV scalar, but find it out of reach at the LHC.

   hep-phhep-exPRD(2020)·15 citations
8. 08*

   Strong decays analysis of excited nonstrange charmed mesons: Implications for spectroscopy

   Keval Gandhi🇮🇳 · Ajay Kumar Rai🇮🇳

   The strong decays of $D_1(2420{)}^0$, $D_2^{\ast }(2460{)}^0$, $D_2^{\ast }(2460{)}^{+}$, $D_2^{\ast }(2460{)}^{-}$, $D(2550{)}^0$, $D_J^{\ast }(2600{)}^0$, $D(2740{)}^0$, $D_3^{\ast }(2750{)}^0$, $D_3^{\ast }(2750{)}^{+}$, $D_3^{\ast }(2750{)}^{-}$, $D_J(3000{)}^0$, $D{}_J^{\ast }(3000{)}^0$ and $D_2^{\ast }(3000{)}^0$ resonance states are analyzed in the heavy quark mass limit of Heavy Quark Effective Theory (HQET). The individual decay rates and the branching ratios among the strong decays determine their spin and parity. From such states the Regge trajectories are constructed in $(J,M^2)$ and $(n_r,M^2)$ planes and further predict the masses of higher excited states (1${}^1{D}_2$, 1${}^3{D}_3$, 3${}^1{S}_0$, 3${}^3{S}_1$, 1${}^1{F}_3$, 1${}^3{F}_4$, 2${}^3{D}_3$, 3${}^3{P}_2$ and 2${}^3{F}_4$) lying on Regge lines by fixing their slopes and intercepts. Moreover, the strong decay rates and the branching ratios of these higher excited states are also examined, which can help the experimentalists to search these states into their respective decay modes.

   hep-phEPJA(2021)·12 citations
9. 09*

   ${\Xi }_c$ and ${\Xi }_b$ excited states within a ${\mathrm{SU}(6)}_{\mathrm{lsf}}\times$HQSS model

   J. Nieves🇪🇸 · R. Pavao🇪🇸 · L. Tolos🇩🇪

   We study odd parity $J=1/2$ and $J=3/2$ ${\Xi }_c$ resonances using a unitarized coupled-channel framework based on a ${\mathrm{SU}(6)}_{\mathrm{lsf}}\times$HQSS-extended Weinberg-Tomozawa baryon-meson interaction, while paying a special attention to the renormalization procedure. We predict a large molecular ${\Lambda }_c\bar{K}$ component for the ${\Xi }_c(2790)$ with a dominant $0^{-}$ light-degree-of-freedom spin configuration. We discuss the differences between the $3/2^{-}$ ${\Lambda }_c(2625)$ and ${\Xi }_c(2815)$ states, and conclude that they cannot be SU(3) siblings, whereas we predict the existence of other ${\Xi }_c-$states, two of them related to the two-pole structure of the ${\Lambda }_c(2595)$. It is of particular interest a pair of $J=1/2$ and $J=3/2$ poles, which form a HQSS doublet and that we tentatively assign to the ${\Xi }_c(2930)$ and ${\Xi }_c(2970)$, respectively. Within this picture, the ${\Xi }_c(2930)$ would be part of a SU(3) sextet, containing either the ${\Omega }_c(3090)$ or the ${\Omega }_c(3119)$, and that would be completed by the ${\Sigma }_c(2800)$. Moreover, we identify a $J=1/2$ sextet with the ${\Xi }_b(6227)$ state and the recently discovered ${\Sigma }_b(6097)$. Assuming the equal spacing rule and to complete this multiplet, we predict the existence of a $J=1/2$ ${\Omega }_b$ odd parity state, with a mass of 6360 MeV and that should be seen in the ${\Xi }_b\bar{K}$ channel.

   hep-phhep-exnucl-thEPJC(2020)·45 citations
10. 10*

    Investigation of a kind of neutrino mass matrix

    Chao-Shang Huang🇨🇳 · Wen-Jun Li🇨🇳

    We carry out diagonalization of a kind of Majorana neutrino mass matrix $M=M_{\nu }{M}_{\nu }^{†}$ of which Real part and Imaginary part are commutative. For the kind of matrix M, it is shown in a model-independent way that $\delta =\pm \pi /2$ which implies the maximal strength of CP violation in neutrino oscillations and atmospherical mixing angle would be in the ranges, $\pi /4<{\theta }_{23}<3\pi /4$, or $-3\pi /4<{\theta }_{23}<-\pi /4$. It is shown that the kind of Hermitian Majorana neutrino mass matrix M has only five real parameters and furthermore, only one free real parameter (A or D) if using the measured values of three mixing angles and mass squared differences as inputs.

    hep-phJ.Phys.G(2022)·2 citations
11. 11*

    NNLO QCD$\times$EW corrections to Z production in the $q\bar{q}$ channel

    Roberto Bonciani🇮🇹 · Federico Buccioni🇬🇧 · Narayan Rana🇮🇹 · Ilario Triscari🇮🇹 · Alessandro Vicini🇮🇹

    We present the first results for the $\mathcal{O}(\alpha {\alpha }_s)$ corrections to the total partonic cross section of the process $q\bar{q}\to Z+X$, with the complete set of contributions, that include photonic and massive weak gauge boson effects. The results are relevant for the precise determination of the hadronic $Z$ boson production cross section. Virtual and real corrections are calculated analytically using the reduction to the master integrals and their evaluation through differential equations. Real corrections are dealt with using the reverse-unitarity method. They require the evaluation of a new set of two-loop master integrals, with up to three internal massive lines. In particular, three of them are expressed in terms of elliptic integrals. We verify the absence, at this perturbative order, of initial state mass singularities proportional to a weak massive virtual correction to the quark-gluon splitting.

    hep-phhep-exPRD(2020)·58 citations
12. 12*

    Flavour Anomalies

    Antonio Pich🇪🇸

    The experimental data on $b\to c\tau {\bar{\nu }}_{\tau }$ and $b\to s{\ell }^{+}{\ell }^{-}$ transitions exhibit sizeable discrepancies with the Standard Model expectations. We present an overview of the present status and discuss possible interpretations within a model-independent effective Lagrangian approach. We also briefly elaborate on some other claimed flavour anomalies such as the recently observed CP asymmetry in $D^0$ decays or the $K^0\to \pi \pi$ ratio ${\epsilon }_K^{\prime }/{\epsilon }_K^{}$. The Standard Model prediction for the direct $CP$-violating ratio ${\epsilon }_K^{\prime }/{\epsilon }_K^{}$ agrees with its measured value, once all theoretical ingredients are correctly taken into account.

    hep-phhep-exPoS(2019)·18 citations
13. 13*

    Anomalies in B Decays: A Sign of New Physics?

    David London🇨🇦

    At the present time, there are a number of measurements of $B$-decay observables that disagree with the predictions of the standard model. These discrepancies have been seen in processes governed by two types of decay: (i) $b\to s{\mu }^{+}{\mu }^{-}u$ and (ii) $b\to c{\tau }^{-}\bar{\nu }$. In this talk, I review the experimental results, as well as the proposed new-physics explanations. We may be seeing the first signs of physics beyond the standard model.

    hep-ph7 citations
14. 14*

    Hunting for ALPs with Lepton Flavor Violation

    Claudia Cornella🇨🇭 · Paride Paradisi🇮🇹 · Olcyr Sumensari🇮🇹

    We examine the low-energy signatures of axion-like particles (ALPs) in lepton flavor violating (LFV) processes. By using a dimension-5 effective Lagrangian, we compute the most general ALP contributions to LFV decays of leptons and mesons. The provided expressions are valid for any choice of ALP mass and couplings. We explore the complementarity of different processes, identifying specific patterns to be experimentally tested. Constraints on LFV couplings are derived from existing data and prospects for forthcoming experiments are also discussed. As a by-product, we revisit the possibility of a simultaneous explanation of the observed discrepancies in the muon and electron $g-2$ through ALP interactions.

    hep-phhep-exJHEP(2020)·204 citations
15. 15*

    Neutrino Oscillation in Dense Matter

    Shu Luo🇨🇳

    As the increasing of neutrino energy or matter density, the neutrino oscillation in matter may undergo "vacuum-dominated", "resonance" and "matter-dominated" three different stages successively. Neutrinos endure very different matter effects, and therefore present very different oscillation behaviors in these three different cases. In this paper, we focus on the less discussed matter-dominated case (i.e., $|A_{\mathrm{CC}}^{}|\gg |\Delta m_{31}^2|$), study the effective neutrino mass and mixing parameters as well as neutrino oscillation probabilities in dense matter using the perturbation theory. We find that as the matter parameter $|A_{\mathrm{CC}}^{}|$ growing larger, the effective mixing matrix in matter $\tilde{V}$ evolves approaching a fixed $3\times 3$ constant real matrix which is free of CP violation and can be described using only one simple mixing angle $\tilde{\theta }$ which is independent of $A_{\mathrm{CC}}^{}$. As for the neutrino oscillation behavior, ${\nu }_e^{}$ decoupled in the matter-dominated case due to its intense charged-current interaction with electrons while a two-flavor oscillation are still presented between ${\nu }_{\mu }^{}$ and ${\nu }_{\tau }^{}$. Numerical analysis are carried on to help understanding the salient features of neutrino oscillation in matter as well as testing the validity of those concise approximate formulas we obtained. At the end of this paper, we make a very bold comparison of the oscillation behaviors between neutrinos passing through the Earth and passing through a typical white dwarf to give some embryo thoughts on under what circumstances these studies will be applied and put forward the interesting idea of possible "neutrino lensing" effect.

    hep-phastro-ph.HEPRD(2020)·13 citations
16. 16*

    The complete set of two-loop master integrals for Higgs + jet production in QCD

    Hjalte Frellesvig🇮🇹 · Martijn Hidding🇮🇪 · Leila Maestri🇩🇪 · Francesco Moriello🇨🇭 · Giulio Salvatori🇺🇸

    In this paper we complete the computation of the two-loop master integrals relevant for Higgs plus one jet production initiated in arXiv:1609.06685, arXiv:1907.13156, arXiv:1907.13234. We compute the integrals by defining differential equations along contours in the kinematic space, and by solving them in terms of one-dimensional generalized power series. This method allows for the efficient evaluation of the integrals in all kinematic regions, with high numerical precision. We show the generality of our approach by considering both the top- and the bottom-quark contributions. This work along with arXiv:1609.06685, arXiv:1907.13156, arXiv:1907.13234 provides the full set of master integrals relevant for the NLO corrections to Higgs plus one jet production, and for the real-virtual contributions to the NNLO corrections to inclusive Higgs production in QCD in the full theory.

    hep-phhep-thJHEP(2020)·66 citations
17. 17*

    Warming Nuclear Pasta with Dark Matter: Kinetic and Annihilation Heating of Neutron Star Crusts

    Javier F. Acevedo🇨🇦 · Joseph Bramante🇨🇦 · Rebecca K. Leane🇺🇸 · Nirmal Raj🇨🇦

    Neutron stars serve as excellent next-generation thermal detectors of dark matter, heated by the scattering and annihilation of dark matter accelerated to relativistic speeds in their deep gravitational wells. However, the dynamics of neutron star cores are uncertain, making it difficult at present to unequivocally compute dark matter scattering in this region. On the other hand, the physics of an outer layer of the neutron star, the crust, is more robustly understood. We show that dark matter scattering solely with the low-density crust still kinetically heats neutron stars to infrared temperatures detectable by forthcoming telescopes. We find that for both spin-independent and spin-dependent scattering on nucleons, the crust-only cross section sensitivity is $10^{-43}-10^{-41}$~cm${}^2$ for dark matter masses of 100 MeV $-$ 1 PeV, with the best sensitivity arising from dark matter scattering with a crust constituent called nuclear pasta (including gnocchi, spaghetti, and lasagna phases). For dark matter masses from 10 eV to 1 MeV, the sensitivity is $10^{-39}-10^{-34}$~cm${}^2$, arising from exciting collective phonon modes in a neutron superfluid in the inner crust. Furthermore, for any $s$-wave or $p$-wave annihilating dark matter, we show that dark matter will efficiently annihilate by thermalizing just with the neutron star crust, regardless of whether the dark matter ever scatters with the neutron star core. This implies efficient annihilation in neutron stars for any electroweakly interacting dark matter with inelastic mass splittings of up to 200 MeV, including Higgsinos. We conclude that neutron star crusts play a key role in dark matter scattering and annihilation in neutron stars.

    hep-phastro-ph.HEastro-ph.SRJCAP(2020)·111 citations
18. 18*

    Neutrino Flavor Transformations from New Short-Range Forces

    B.J.P. Jones🇺🇸 · J. Spitz🇺🇸

    We examine the commonly explored beyond-standard-model physics scenario of secret neutrino forces, and point out a model prediction that appears to have been overlooked: the generation of unique flavor-changing effects in experiments featuring decay-at-rest (DAR) neutrino sources. These flavor changes occur because the decay that drives neutrino and antineutrino production, ${\mu }^{+}\to e^{+}+{\bar{\nu }}_{\mu }+{\nu }_e$, is unique in producing two neutrinos in the final state. Any non-flavor-universal force between the emerging neutrinos would thus induce a new oscillation phase as they escape from each-other's potential wells, an effect which is largely absent in experiments that primarily rely on meson decay-in-flight and nuclear decay. We calculate the magnitude of the associated observable and compare it to the anomalous neutrino flavor transformation seen by the LSND experiment, finding a wide but constrained allowed parameter space. We also evaluate existing limits from other experiments, and the testability of this new effect at the future DAR programs JSNS${}^2$ and OscSNS.

    hep-phhep-ex11 citations
19. 19*

    Capturing Non-Gaussianity of the Large-Scale Structure with Weighted Skew-Spectra

    Azadeh Moradinezhad Dizgah🇺🇸 · Hayden Lee🇺🇸 · Marcel Schmittfull · Cora Dvorkin🇺🇸

    The forthcoming generation of wide-field galaxy surveys will probe larger volumes and galaxy densities, thus allowing for a much larger signal-to-noise ratio for higher-order clustering statistics, in particular the galaxy bispectrum. Extracting this information, however, is more challenging than using the power spectrum due to more complex theoretical modeling, as well as significant computational cost of evaluating the bispectrum signal and the error budget. To overcome these challenges, several proxy statistics have been proposed in the literature, which partially or fully capture the information in the bispectrum, while being computationally less expensive than the bispectrum. One such statistics are {\it weighted skew-spectra}, which are cross-spectra of the density field and appropriately weighted quadratic fields. Using Fisher forecasts, we show that the information in these skew-spectra is equivalent to that in the bispectrum for parameters that appear as amplitudes in the bispectrum model, such as galaxy bias parameters or the amplitude of primordial non-Gaussianity. We consider three shapes of the primordial bispectrum: local, equilateral and that due to massive particles with spin two during inflation. To obtain constraints that match those from a measurement of the full bispectrum, we find that it is crucial to account for the full covariance matrix of the skew-spectra.

    ↳ astro-ph.COhep-phJCAP(2020)·61 citations
20. 20*

    Comments on the CKN Bound

    Tom Banks🇺🇸 · Patrick Draper🇺🇸

    Cohen, Kaplan, and Nelson (CKN) conjectured that the UV and IR cutoffs of effective quantum field theories coupled to gravity are not independent, but are connected by the physics of black holes. We interpret the CKN bound as a scale-dependent depletion of the QFT density of states and discuss various aspects of the bound on small and large scales. For laboratory experiments, we argue that the bound provides small corrections to ordinary quantum field theory, which we estimate to be of order $m_e/M_p$ for $g-2$ of the electron. On large scales, we suggest a modification of the CKN bound due to the presence of cosmological horizons and discuss the connection with entropy bounds.

    ↳ hep-thastro-ph.COhep-phPRD(2020)·49 citations
21. 21*

    A Map Between Primordial Power Spectra and the Effective Field Theory of Inflation

    Amel Durakovic🇩🇰

    We have developed a precise dictionary between the spectrum of primordial density fluctuations and the parameters of the effective field theory (EFT) of inflation that determine the primordial power spectrum (PPS). At lowest order the EFT contains two parameters: the slow-roll parameter $ϵ$, which acts as an order parameter, and the speed of sound $c_s$. Applying second-order perturbation theory, we provide maps from the PPS to the EFT parameters that are precise up to the cube of the fractional change in the PPS $(\Delta \mathcal{P}/\mathcal{P}{)}^3$, or less than $1\%$ for spectral features that modulate the PPS by $20\%$. While such features are not required when the underlying cosmological model is assumed to be $\Lambda$CDM they are necessary for alternative models that have no cosmological constant/dark energy. We verify the dictionary numerically and find those excursions in the slow-roll parameter that reproduce the PPS needed to fit Planck data for both $\Lambda$ and no-$\Lambda$ cosmological models.

    ↳ astro-ph.COhep-ph0 citations
22. 22*

    Testing kinetically coupled inflation models with CMB distortions

    Rui Dai🇨🇳 · Yi Zhu🇨🇳

    Inflation scenarios kinetically coupled with the Einstein tensor have been widely studied. They can be consistent with current observational data. Future experiments on the measurement on CMB distortions will potentially extend information about the scalar spectrum to small scales $1{\text{Mpc}}^{-1}\lesssim k\lesssim 2\times 10^4{\text{Mpc}}^{-1}$. By taking the sensitivity of the PIXIE experiment as the criterion, we perform a model-oriented analysis of the observational prospects of spectral distortions for kinetically coupled inflation. There are five models that possibly generate a detectable level of distortions, among the 49 single-field inflation models listed in Ref. \cite{Martin2013a}. These models are: hybrid inflation in the valley (VHI), non-canonical Kähler inflation (NCKI), generalized MSSM inflation (GMSSMI), generalized renormalization point inflation (GRIPI), and running-mass inflation (RMI). Each of these models can satisfy the Planck constraints on spectral tilt and lead to increase power on scales relevant for CMB distortions in a tuned region of their parameter space. The existence of kinetic coupling suppresses the value of the model parameters with mass dimension for VHI, GMSSMI, and GRIPI, such that these three models can be in agreement with their theoretical considerations. However, the tuned regions for all these models fail to satisfy the constraints on tensor modes.

    ↳ astro-ph.COgr-qchep-phJCAP(2020)·4 citations
23. 23*

    Froissart bound for/from CFT Mellin amplitudes

    Parthiv Haldar🇮🇳 · Aninda Sinha🇮🇳

    We derive bounds analogous to the Froissart bound for the absorptive part of CFT${}_d$ Mellin amplitudes. Invoking the AdS/CFT correspondence, these amplitudes correspond to scattering in AdS${}_{d+1}$. We can take a flat space limit of the corresponding bound. We find the standard Froissart-Martin bound, including the coefficient in front for $d+1=4$ being $\pi /{\mu }^2$, $\mu$ being the mass of the lightest exchange. For $d>4$, the form is different. We show that while for $CF{T}_{d\le 6}$, the number of subtractions needed to write a dispersion relation for the Mellin amplitude is equal to 2, for $CF{T}_{d>6}$ the number of subtractions needed is greater than 2 and goes to infinity as $d$ goes to infinity.

    ↳ hep-thhep-phSciPost Phys.(2020)·20 citations
24. 24*

    Fundamental Physics, the Swampland of Effective Field Theory and Early Universe Cosmology

    Robert Brandenberger (McGill University)🇨🇦

    Cosmological inflation is not the only early universe scenario consistent with current observational data. I will discuss the criteria for a successful early universe cosmology, compare a couple of the proposed scenarios (inflation, bouncing cosmologies, and the {\it emergent} scenario), focusing on how future observational data will be able to distinguish between them. I will argue that we need to go beyond effective field theory in order to understand the early universe, and that principles of superstring theory will yield a nonsingular cosmology.

    ↳ hep-thastro-ph.COgr-qchep-ph22 citations
25. 25*

    Signatures of Dark Matter in Cosmic-Ray Observations

    Alessandro Cuoco🇩🇪

    I provide a short review of the current status of indirect dark matter searches with gamma rays, charged cosmic rays and neutrinos. For each case I will focus on various excesses reported in the literature which have been interpreted as possible hints of dark matter, and I will use them as examples to discuss theoretical aspects and analysis methodologies.

    ↳ astro-ph.HEhep-phJ.Phys.Conf.Ser.(2020)·3 citations
26. 26*

    Classical production of 't Hooft-Polyakov monopoles from magnetic fields

    David L.-J. Ho🇬🇧 · Arttu Rajantie🇬🇧

    We show that in the SU(2) Georgi-Glashow model, 't Hooft-Polyakov monopoles are produced by a classical instability in magnetic fields above the Ambjorn-Olesen critical field, which coincides approximately with the field at which Schwinger pair production becomes unsuppressed. Below it, monopoles can be produced thermally, and we show that the rate is higher than for pointlike monopoles by calculating the sphaleron energy as a function of the magnetic field. The results can be applied to production of monopoles in heavy-ion collisions or in the early Universe.

    ↳ hep-thhep-lathep-phPRD(2020)·34 citations
27. 27*

    Partial-Symmetry-Breaking Phase Transitions

    Masanori Hanada🇬🇧 · Brandon Robinson🇬🇧

    We demonstrate a novel feature of certain phase transitions in theories with large rank symmetry group that exhibit specific types of non-local interactions. A typical example of such a theory is a large-$N$ gauge theory where by `non-local interaction' we mean the all-to-all coupling of color degrees of freedom. Recently it has been pointed out that nontrivial features of the confinement/deconfinement transition are understood as consequences of the coexistence of the confined and deconfined phases on the group manifold describing the color degrees of freedom. While these novel features of the confinement/deconfinement transition are analogous to the two-phase coexistence at the first order transition of more familiar local theories, various differences such as the partial breaking of the symmetry group appear due to the non-local interaction. In this article, we show that similar phase transitions with partially broken symmetry can exist in various examples from QFT and string theory. Our examples include the deconfinement and chiral transition in QCD, Gross-Witten-Wadia transition in two-dimensional lattice gauge theory, Douglas-Kazakov transition in two-dimensional gauge theory on sphere, and black hole/black string transition.

    ↳ hep-thhep-lathep-phPRD(2020)·32 citations
28. 28*

    Thermal Friction as a Solution to the Hubble Tension

    Kim V. Berghaus🇺🇸 · Tanvi Karwal🇺🇸

    A new component added to the standard model of cosmology that behaves like a cosmological constant at early times and then dilutes away as radiation or faster can resolve the Hubble tension. We show that a rolling axion coupled to a non-Abelian gauge group exhibits the behavior of such an extra component at the background level and can present a natural particle-physics model solution to the Hubble tension. We compare the contribution of this bottom-up model to the phenomenological fluid approximation and determine that CMB observables sensitive only to the background evolution of the Universe are expected to be similar in both cases, strengthening the case for this model to provide a viable solution to the Hubble tension.

    ↳ astro-ph.COhep-phhep-thPRD(2020)·151 citations
29. 29*

    The Double Copy of Electric-Magnetic Duality

    Yu-tin Huang🇹🇼 · Uri Kol🇺🇸 · Donal O'Connell🇬🇧

    We argue that the complex transformation relating the Schwarzschild to the Taub-NUT metric, introduced by Talbot, is in fact an electric-magnetic duality transformation. We show that at null infinity, the complex transformation is equivalent to a complexified BMS supertranslation, which rotates the supertranslation and the dual (magnetic) supertranslation charges. This can also be seen from the cubic coupling between the classical source and its background, which for Taub-NUT is given by a complex phase rotation acting on gravitational minimal couplings. The same phase rotation generates dyons from electrons at the level of minimally coupled amplitudes, manifesting the double copy relation between the two solutions.

    ↳ hep-thgr-qchep-phPRD(2020)·141 citations
30. 30*

    Confinement as Analytic Continuation Beyond Infinity

    Masahito Yamazaki🇯🇵 · Kazuya Yonekura🇯🇵

    We propose a mechanism for confinement: analytic continuation beyond infinite coupling in the space of the coupling constant. The analytic continuation is realized by renormalization group flows from the weak to the strong coupling regime. We demonstrate this mechanism explicitly for the mass gap in two-dimensional sigma models in the large $N$ limit. Our analysis suggests that the conventional analysis of the operator product expansion in itself does not necessarily guarantee the existence of a classical solution corresponding to renormalons. We discuss how the renormalon puzzle may be resolved by the analytic continuation beyond infinite coupling.

    ↳ hep-thhep-lathep-phPRResearch(2020)·10 citations
31. 31*

    The d*(2380) and its family of pion assisted dibaryons

    Avraham Gal🇮🇱

    The status of $N\Delta$ and $\Delta \Delta$ dibaryons introduced by Dyson and Xuong in 1964 is briefly reviewed with focus on the d*(2380), tentatively assigned as a $\Delta \Delta$ dibaryon resonance. It is argued that the apparently small value of width, ${\Gamma }_{d^{\ast }}$$\approx$70 MeV, favors hadronic structure for the d*(2380) dibaryon rather than a six-quark structure.

    ↳ nucl-thhep-phnucl-ex0 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.