Mon·Dec 9, 2019Monday·December 9, 2019

1. 01*

   Precision calculations of dark matter relic abundance

   Kalle Ala-Mattinen🇫🇮 · Kimmo Kainulainen🇫🇮

   The dark matter annihilation channels sometimes involve sharp resonances. In such cases the usual momentum averaged approximations for computing the DM abundance may not be accurate. We develop an easily accessible momentum dependent framework for computing the DM abundance accurately and efficiently near such features. We apply the method to the case of a singlet scalar dark matter $s$ interacting with SM through higgs portal ${\lambda }_{\mathrm{hs}}{s}^2{h}^2$ and compare the results with different momentum averaged methods. The accuracy of the latter depend strongly on the strength of the elastic interactions and corrections are large if WIMP has negligible interactions beyond the main annihilation channel. In the singlet scalar model however, the standard model scatterings induce an efficient kinetic equilibrium that validates the momentum averaged computation to 20 per cent accuracy. We update the current extent of the allowed region in the light singlet scalar dark matter to $m_{\mathrm{S}}\in [56,62.5]$ GeV.

   hep-phastro-ph.COJCAP(2020)·28 citations
2. 02*

   Implications of spin symmetry for XYZ states

   Q. Wang🇨🇳 · V. Baru🇩🇪 · E. Epelbaum🇩🇪 · A.A. Fillin🇩🇪 · C. Hanhart🇩🇪 · A.V. Nefediev🇷🇺 · J.L. Wynen🇩🇪

   Numerous exotic candidates containing a heavy quark and anti-quark (the so-called $XYZ$ states) have been reported since the observation of the $X(3872)$ in 2003. For these systems a study of the implications of the heavy quark spin symmetry and its breaking is expected to provide useful guidance towards a better understanding of their nature. For instance, since the formation of the complete spin multiplets is described with the same parameter sets, in some cases the currently available experimental data on the $XYZ$ states allows us to predict properties of spin partner states. To illustrate this point we extract the parameters of the two $Z_b$ states by analyzing the most recent experimental data within an effective-field theory approach which treats both short-ranged contact interactions and the long-ranged one-pion/one-eta Goldstone boson exchanges (OPE/OEE) dynamically. The line shapes and pole positions of their spin partners are then predicted in a parameter-free way and await to be tested by future experimental data.

   hep-ph0 citations
3. 03*

   Hunting the Glashow Resonance with PeV Neutrino Telescopes

   Guo-yuan Huang🇨🇳 · Qinrui Liu🇺🇸

   The Glashow resonant scattering, $i.e$. ${\overline{\nu }}_e^{}+e^{-}\to W^{-}\to \text{anything}$, offers us a possibility of disentangling ${\overline{\nu }}_e^{}$ from the total astrophysical neutrino fluxes. Meanwhile, a great number of high-energy neutrino telescopes, with various detection mechanisms, are advancing towards a better understanding of one of the most energetic frontiers of the Universe. In this work, we investigate a connection between through-going muons at IceCube and the Glashow resonance signal through the channel $W^{-}\to \mu$. We find that for IceCube, muons from ${\overline{\nu }}_e^{}$ can induce a $\sim 20\%$ excess of PeV events around the horizontal direction. However, the current statistic of IceCube is not enough to observe such an excess. We also address the novel possibility of ${\overline{\nu }}_e^{}$ detection via $W^{-}\to \tau$ at telescopes aiming to detect Earth-skimming and mountain-penetrating neutrinos. The subsequent hadronic decay of a tau will induce an extensive air shower which can be detected by telescopes with Cherenkov or fluorescence techniques. Similar to IceCube, it is challenging to observe the Glashow resonance excess from the Earth-skimming neutrinos. Nevertheless, we find it is promising to observe Glashow resonance events with a mountain as the target.

   hep-phastro-ph.HEJCAP(2020)·33 citations
4. 04*

   Effects of vector leptoquarks on ${\Lambda }_b\to {\Lambda }_c\ell {\overline{\nu }}_{\ell }$ decay

   K. Azizi🇮🇷 · A. T. Olgun🇹🇷 · Z. Tavukoglu🇹🇷

   Experimental data on $R(D^{(\ast )})$, $R(K^{(\ast )})$ and $R(J/\psi )$, provided by different collaborations, show sizable deviations from the SM predictions. To describe these anomalies many new physics scenarios have been proposed. One of them is leptoquark model with introducing the vector and scalar leptoquarks coupling simultaneously to the quarks and leptons. To look for similar possible anomalies in baryonic sector, we investigate the effects of a vector leptoquark $U_3(3,3,\frac{2}{3})$ on various physical quantities related to the tree-level ${\Lambda }_b\to {\Lambda }_c\ell {\overline{\nu }}_{\ell }$ decays ($\ell =\mu ,\tau$), which proceed via $b\to c\ell {\overline{\nu }}_{\ell }$ transitions at quark level. We calculate the differential branching ratio, forward-backward asymmetry and longitudinal polarizations of lepton and ${\Lambda }_c$ baryon at $\mu$ and $\tau$ lepton channels in leptoquark model and compare their behavior with respect to $q^2$ with the predictions of the standard model (SM). In the calculations we use the form factors calculated in full QCD as the main inputs and take into account all the errors coming from the form factors and model parameters. It is observed that ........

   hep-phhep-exhep-latCPC(2021)·13 citations
5. 05*

   ${\rm Y}(nl)$ decay into $B^{(\ast )}{\bar{B}}^{(\ast )}$

   Wei-Hong Liang🇨🇳 · Natsumi Ikeno🇯🇵 · Eulogio Oset🇪🇸

   We have evaluated the decay modes of the ${\rm Y}(4s),{\rm Y}(3d),{\rm Y}(5s),{\rm Y}(6s)$ states into $B\bar{B},B{\bar{B}}^{\ast }+c.c.,B^{\ast }{\bar{B}}^{\ast },B_s{\bar{B}}_s,B_s{\bar{B}}_s^{\ast }+c.c.,B_s^{\ast }{\bar{B}}_s^{\ast }$ using the ${}^3{P}_0$ model to hadronize the $b\bar{b}$ vector seed, fitting some parameters to the data. We observe that the ${\rm Y}(4s)$ state has an abnormally large amount of meson-meson components in the wave function, while the other states are largely $b\bar{b}$. We predict branching ratios for the different decay channels which can be contrasted with experiment for the case of the ${\rm Y}(5s)$ state. While globally the agreement is fair, we call the attention to some disagreement that could be a warning for the existence of more elaborate components in the state.

   hep-phPLB(2020)·35 citations
6. 06*

   Neutrinoless double beta decay versus other probes of heavy sterile neutrinos

   Patrick D. Bolton🇬🇧 · Frank F. Deppisch🇬🇧 · P. S. Bhupal Dev🇺🇸

   We make a comparative study of the neutrinoless double beta decay constraints on heavy sterile neutrinos versus other direct and indirect constraints from both lepton number conserving and violating processes, as a sensitive probe of the extent of lepton number violation and possible interference effects in the sterile sector. We introduce a phenomenological parametrisation of the simplified one-generation seesaw model with one active and two sterile neutrino states in terms of experimentally measurable quantities, such as active-sterile neutrino mixing angles, CP phases, masses and mass splittings. This simple parametrisation enables us to analytically derive a spectrum of possible scenarios between the canonical seesaw with purely Majorana heavy neutrinos and inverse seesaw with pseudo-Dirac ones. We then go on to constrain the simplified parameters of this model from various experiments at the energy, intensity and cosmic frontiers. We emphasise that the constraints from lepton number violating processes strongly depend on the mass splitting between the two sterile states and the relative CP phase between them. This is particularly relevant for neutrinoless double beta decay, which is weakened for small mass splitting and opposite CP parities between the sterile states. On the other hand, neutrinoless double beta decay is especially sensitive for Majorana sterile neutrinos with masses around $0.1-10$ GeV.

   hep-phJHEP(2020)·258 citations
7. 07*

   Analytic multi-loop results using finite fields and dataflow graphs with FiniteFlow

   Tiziano Peraro🇨🇭

   FiniteFlow is a public framework for defining and executing numerical algorithms over finite fields and reconstructing multivariate rational functions. The framework allows to build complex algorithms by combining basic building blocks into graphical representations of the calculation, known as dataflow graphs. It offers an easy-to-use Mathematica interface for implementing efficient custom algorithms without any low-level coding. We report on some new features of FiniteFlow which have been published after its initial release, give some simple example of usage for common tasks and review recent cutting-edge applications to two-loop five-point scattering and the four-loop cusp anomalous dimension.

   hep-phhep-th13 citations
8. 08*

   Mass inequalities for baryons with heavy quarks

   Marek Karliner🇮🇱 · Jonathan L. Rosner🇺🇸

   Baryons with one or more heavy quarks have been shown, in the context of a nonrelativistic description, to exhibit mass inequalities under permutations of their quarks, when spin averages are taken. These inequalities sometimes are invalidated when spin-dependent forces are taken into account. A notable instance is the inequality $2E(Mmm)>E(MMm)+E(mmm)$, where $m=m_u=m_d$, satisfied for $M=m_b$ or $M=m_c$ but not for $M=m_s$, unless care is taken to remove effects of spin-spin interactions. Thus in the quark-level analog of nuclear fusion, the reactions ${\Lambda }_b{\Lambda }_b\to {\Xi }_{bb}N$ and ${\Lambda }_c{\Lambda }_c\to {\Xi }_{cc}^{++}n$ are exothermic, releasing respectively 138 and 12 MeV, while $\Lambda \Lambda \to \Xi N$ is endothermic, requiring an input of between 23 and 29 MeV. Here we explore such mass inequalities in the context of an approach, previously shown to predict masses successfully, in which contributions consist of additive constituent-quark masses, spin-spin interactions, and additional binding terms for pairs each member of which is at least as heavy as a strange quark.

   hep-phPRD(2020)·4 citations
9. 09*

   Scale-dependence of the $B$-meson LCDA beyond leading order from conformal symmetry

   V.M. Braun🇩🇪 · Yao Ji🇩🇪 · A.N. Manashov🇩🇪

   We argue that the evolution kernel for the scale-dependence of the $B$-meson light-cone distribution amplitude (LCDA) can be written, to all orders in perturbation theory, in terms of the generator of special conformal transformations in a modified theory: QCD at critical coupling in non-integer $d\ne 4$ dimensions. Explicit expression for the eigenfunctions of the evolution kernel is derived that is valid, again, to all orders. From a practitioner's point of view the utility of this representation is that it allows to "save one loop" and obtain the evolution kernel to a given order of perturbation theory, up to a constant term, from the calculation of the conformal anomaly at one order less. This construction is verified by explicit calculation at two-loop level.

   hep-ph8 citations
10. 10*

    Reinterpreting $pp\to W^{+}{W}^{-}$ searches for charginos

    Antonio Delgado🇺🇸 · Adam Martin🇺🇸

    The hallmark way to search for electroweakinos in natural supersymmetry at the LHC involves the trilepton plus missing energy final state. This approach assumes an electroweakino mass hierarchy that allows for cascade decays leading to a final state of $W^{\pm }{Z}^0$ plus missing energy. There are, however, situations when that decay pattern may not exist, such as when a chargino is the lightest electroweakino and the lightest supersymmetric particle is the gravitino. In regions of the parameter space where this ordering occurs, the production of any combination of neutralino/chargino leads to a $W^{+}{W}^{-}+X$ plus missing energy final state, where $X$ could be additional jets or leptons. If $X$ is soft, then all neutralino/chargino production modes fall into the same experimental final state, dileptons plus missing energy. ATLAS and CMS have leptonic $W^{+}{W}^{-}$ plus missing energy searches, but their interpretation assumes a spectrum consisting of an isolated charged state. In this paper, we identify the circumstances under which natural supersymmetry models can avoid $W^{\pm }{Z}^0$ plus missing energy bounds. For scenarios that escape $W^{\pm }{Z}^0$ plus missing energy, we then recast the latest ATLAS $W^{+}{W}^{-}$ plus missing energy search, taking into account all the states that contribute to the same signal. Assuming the lightest supersymmetric particle is massless, we find a bound of 460 GeV for a higgsino-like degenerate doublet. Finally, we extend our arguments to a non-supersymmetric simplified model containing new electroweak-scale $SU(2{)}_w$ doublets and singlets.

    hep-phPRD(2020)·2 citations
11. 11*

    BSM with Cosmic Strings: Heavy, up to EeV mass, Unstable Particles

    Yann Gouttenoire🇩🇪 · Géraldine Servant🇩🇪 · Peera Simakachorn🇩🇪

    Unstable heavy particles well above the TeV scale are unaccessible experimentally. So far, Big-Bang Nucleosynthesis (BBN) provides the strongest limits on their mass and lifetime, the latter being shorter than 0.1 second. We show how these constraints could be potentially tremendously improved by the next generation of Gravitational-Wave (GW) interferometers, extending to lifetimes as short as $10^{-16}$ second. The key point is that these particles may have dominated the energy density of the universe and have triggered a period of matter domination at early times, until their decay before BBN. The resulting modified cosmological history compared to the usually-assumed single radiation era would imprint observable signatures in stochastic gravitational-wave backgrounds of primordial origin. In particular, we show how the detection of the GW spectrum produced by long-lasting sources such as cosmic strings would provide a unique probe of particle physics parameters. When applied to specific particle production mechanisms in the early universe, these GW spectra could be used to derive new constraints on many UV extensions of the Standard Model. We illustrate this on a few examples, such as supersymmetric models where the mass scale of scalar moduli and gravitino can be constrained up to $10^{10}$ GeV. Further bounds can be obtained on the reheating temperature of models with only-gravitationally-interacting particles as well as on the kinetic mixing of heavy dark photons at the level of $10^{-18}$.

    hep-phastro-ph.COJCAP(2020)·74 citations
12. 12*

    Constrained fit of the valence transversity distributions from dihadron production

    J. Benel🇲🇽 · A. Courtoy🇲🇽 · R. Ferro-Hernandez🇲🇽

    We present a constrained analysis of the valence transversity Parton Distribution Functions from dihadron production in semi-inclusive DIS. While usual extractions of the transversity distributions rely explicitly on the fulfilment of the Soffer bounds, the present analysis releases that implicit restriction to implement further explicit constraints through the Lagrange multipliers method. The results are quantitatively comparable to previous analyses in the kinematical range of data ; the qualitative impact of the chosen fitting strategy translates into an increased flexibility in the functional form.

    hep-phEPJC(2020)·43 citations
13. 13*

    Hadronic interaction model Sibyll 2.3d and extensive air showers

    Felix Riehn🇵🇹 · Ralph Engel🇩🇪 · Anatoli Fedynitch🇯🇵 · Thomas K. Gaisser🇺🇸 · Todor Stanev🇺🇸

    We present a new version of the hadron interaction event generator Sibyll. While the core ideas of the model have been preserved, the new version handles the production of baryon pairs and leading particles in a new way. In addition, production of charmed hadrons is included. Updates to the model are informed by high-precision measurements of the total and inelastic cross sections with the forward detectors at the LHC that constrain the extrapolation to ultra-high energy. Minimum-bias measurements of particle spectra and multiplicities support the tuning of fragmentation parameters. This paper demonstrates the impact of these changes on air shower observables such as $X_{\max }$ and $N_{\mu }$, drawing comparisons with other contemporary cosmic ray interaction models.

    hep-phastro-ph.HEPRD(2020)·408 citations
14. 14*

    GAMBIT and its Application in the Search for Physics Beyond the Standard Model

    Anders Kvellestad🇬🇧 · Pat Scott🇬🇧 · Martin White🇦🇺

    The Global and Modular Beyond-Standard Model Inference Tool (GAMBIT) is an open source software framework for performing global statistical fits of particle physics models, using a wide range of particle and astroparticle data. In this review, we describe the design principles of the package, the statistical and sampling frameworks, the experimental data included, and the first two years of physics results generated with it. This includes supersymmetric models, axion theories, Higgs portal dark matter scenarios and an extension of the Standard Model to include right-handed neutrinos. Owing to the broad spectrum of physics scenarios tackled by the GAMBIT community, this also serves as a convenient, self-contained review of the current experimental and theoretical status of the most popular models of dark matter.

    hep-phPPNP(2020)·37 citations
15. 15*

    Explaining muon $g-2$ data in the $\mu \nu$SSM

    Essodjolo Kpatcha🇪🇸 · Inaki Lara🇵🇱 · Daniel E. Lopez-Fogliani🇦🇷 · Carlos Munoz🇪🇸 · Natsumi Nagata🇯🇵

    We analyze the anomalous magnetic moment of the muon $g-2$ in the $\mu \nu$SSM. This $R$-parity violating model solves the $\mu$ problem reproducing simultaneously neutrino data, only with the addition of right-handed neutrinos. In the framework of the $\mu \nu$SSM, light left muon-sneutrino and wino masses can be naturally obtained driven by neutrino physics. This produces an increase of the dominant chargino-sneutrino loop contribution to muon $g-2$, solving the gap between the theoretical computation and the experimental data. To analyze the parameter space, we sample the $\mu \nu$SSM using a likelihood data-driven method, paying special attention to reproduce the current experimental data on neutrino and Higgs physics, as well as flavor observables such as $B$ and $\mu$ decays. We then apply the constraints from LHC searches for events with multi-leptons + MET on the viable regions found. They can probe these regions through chargino-chargino, chargino-neutralino and neutralino-neutralino pair production. We conclude that significant regions of the parameter space of the $\mu \nu$SSM can explain muon $g-2$ data.

    hep-phEPJC(2021)·16 citations
16. 16*

    Lesson from a soluble model of critical point and primary photons

    G.A. Kozlov🇷🇺

    The critical point in particle physics at high temperature is studied through the ideal gas of scalars, the dilatons, in the model that implies the spontaneous breaking of an approximate scale symmetry. We consider the dynamical system of identical particles weakly interacting to each other. The critical point with the temperature as a function of a dilaton mass is established. The fluctuation of particle density grows up very sharply at critical point. Our results also suggest that the critical point may be identified through the fluctuation in yield of primary photons induced by conformal anomaly of strong and electromagnetic sectors of matter.

    hep-ph0 citations
17. 17*

    Cosmology and Dark Matter

    V. A. Rubakov🇷🇺

    Cosmology and astroparticle physics give strongest possible evidence for the incompleteness of the Standard Model of particle physics. Leaving aside misterious dark energy, which may or may not be just the cosmological constant, two properties of the Universe cannot be explained by the Standard Model: dark matter and matter-antimatter asymmtery. Dark matter particles may well be discovered in foreseeable future; this issue is under intense experimental investigation. Theoretical hypotheses on the nature of the dark matter particles are numerous, so we concentrate on several well motivated candidates, such as WIMPs, axions and sterile neutrinos, and also give examples of less motivated and more elusive candidates such as fuzzy dark matter. This gives an idea of the spectrum of conceivable dark matter candidates, while certainly not exhausting it. We then consider the matter-antimatter asymmetry and discuss whether it may result from physics at 100~GeV -- TeV scale. Finally, we turn to the earliest epoch of the cosmological evolution. Although the latter topic does not appear immediately related to contemporary particle physics, it is of great interest due to its fundamental nature. We emphasize that the cosmological data, notably, on CMB anisotropies, unequivocally show that the well understood hot stage was not the earliest one. The best guess for the earlier stage is inflation, which is consistent with everything known to date; however, there are alternative scenarios. We discuss the ways to study the earliest epoch, with emphasis on future cosmological observations.

    hep-phastro-ph.COCERN Yellow Rep.School Proc.(2022)·21 citations
18. 18*

    Interference Effects for $0\nu \beta \beta$ Decay in the Left-Right Symmetric Model

    Fahim Ahmed🇺🇸 · Mihai Horoi🇺🇸

    Various mechanisms may contribute to neutrinoless double beta decay in the left-right symmetric model. The interference between these mechanisms also contribute to the overall decay rate. The analysis of the contributions of these interference terms is important for disentangling different mechanisms. In the present paper we study interference effects contributing to the decay rate for neutrinoless double-$\beta$ decay in the left-right symmetric model. The numerical values for maximum interference for several nuclides are calculated. It is observed that, for most of the interference terms, the contribution is smaller than 20$\%$ for all the nuclei considered in the study. However, the interference between the mass mechanisms (light and heavy) and $\eta$ mechanism is observed to be in the range 30$\%$-50$\%$. The variation of the interference effect with the $Q$ values is also studied.

    ↳ nucl-thhep-phPRC(2020)·12 citations
19. 19*

    The photon time delay in magnetized vacuum magnetosphere

    A.W. Romero Jorge🇨🇺 · E. Rodríguez Querts🇨🇺 · H. Pérez Rojas🇨🇺 · A. Pérez Martínez🇨🇺 · L. Cruz Rodríguez🇨🇺 · G. Piccinelli Bocchi🇲🇽 · J. A. Rueda🇮🇹

    We study the transverse propagation of photons in a magnetized vacuum considering radiative corrections in the one-loop approximation. The dispersion equation is modified due to the magnetized photon self-energy in the transparency region ($0<\omega <2m_e$). The aim of our study is to explore propagation of photons in a neutron star magnetosphere (described by magnetized vacuum). The solution of the dispersion equation is obtained in terms of analytic functions. The larger the magnetic field, the lower the phase velocity and the more the dispersion curve deviates from the light-cone. For fixed values of the frequency, we study the dependence of photon time delay with the magnetic field strength, as well as with distance. For the latter, we adopt a magnetic dipole configuration and obtain that -- contrary to the expectation, according to the traditional time delay of photons in the interstellar medium -- photons of higher energy experience a longer time delay. A discussion of potential causes of this behaviour is presented.

    ↳ astro-ph.HEhep-phAstron.Nachr.(2019)·4 citations
20. 20*

    Relativistic many-body analysis of the electric dipole moment enhancement factor of 210Fr and associated properties

    Nanako Shitara🇯🇵 · B. K. Sahoo🇮🇳 · T. Watanabe🇯🇵 · B. P. Das🇯🇵

    The relativistic coupled-cluster (RCC) method is a powerful many-body method, particularly in the evaluation of electronic wave functions of heavy atoms and molecules, and can be used to calculate various atomic and molecular properties. One such atomic property is the enhancement factor (R) of the atomic electric dipole moment (EDM) due to an electron EDM needed in electron EDM searches. The EDM of the electron is a sensitive probe of CP-violation, and its search could provide insights into new physics beyond the Standard Model, as well as open questions in cosmology. Electron EDM searches using atoms require the theoretical evaluation of R to provide an upper limit for the magnitude of the electron EDM. In this work, we calculate R of 210Fr in the ground state using an improved RCC method, and perform an analysis on the many-body processes occurring within the system. The RCC method allows one to capture the effects of both the electromagnetic interaction and P- and T-violating interactions, and our work develops this method beyond what had been implemented in the previous works. We also perform calculations of hyperfine structure constants, electric dipole transition matrix elements, and excitation energies, to assess the accuracy of R and the success of our improved method. Finally, we present calculations of R with corrections due to Breit interaction effects, approximate quantum electrodynamics (QED) effects, and some leading triple excitation terms added perturbatively, to assess how significantly these terms contribute to the result. We obtain a final value of R = 799, with an estimated 3% error, which is about 11% smaller than a previously reported theoretical calculation.

    ↳ physics.atom-phhep-ph1 citation
21. 21*

    2019 Update on ${\epsilon }_K$ with lattice QCD inputs

    Jeehun Kim🇰🇷 · Sunkyu Lee🇰🇷 · Weonjong Lee · Yong-Chull Jang🇺🇸 · Jaehoon Leem🇰🇷 · Sungwoo Park (LANL-SWME Collaboration)🇺🇸

    We present updated results for ${\epsilon }_K$ determined directly from the standard model (SM) with lattice QCD inputs such as ${\hat{B}}_K$, $|V_{cb}|$, $|V_{us}|$, ${\xi }_0$, ${\xi }_2$, ${\xi }_{\text{LD}}$, $f_K$, and $m_c$. We find that the standard model with exclusive $|V_{cb}|$ and other lattice QCD inputs describes only 65\% of the experimental value of $|{\epsilon }_K|$ and does not explain its remaining 35\%, which leads to a strong tension in $|{\epsilon }_K|$ at the $4.6\sigma \sim 4.2\sigma$ level between the SM theory and experiment. We also find that this tension disappears when we use the inclusive value of $|V_{cb}|$ obtained using the heavy quark expansion based on QCD sum rules.

    ↳ hep-lathep-phPoS(2019)·9 citations
22. 22*

    The Gravitational Potential of Two Point Masses at Five Loops

    Johannes Blümlein🇩🇪 · Andreas Maier🇩🇪 · Peter Marquard🇩🇪

    Corrections to the Newtonian gravitational potential from general relativity can be derived in a combined expansion around flat spacetime and a small velocity of the interacting bodies. We present the calculation of the static five-loop corrections in an effective field theory framework using techniques from multi-loop computations in particle physics.

    ↳ gr-qchep-phPoS(2019)·1 citation
23. 23*

    Light Hadron Masses from a Matrix Model for QCD

    Mahul Pandey🇮🇪 · Sachindeo Vaidya🇮🇳

    The $SU(3)$ Yang-Mills matrix model coupled to fundamental fermions is an approximation of quantum chromodynamics (QCD) on a 3-sphere of radius $R$. The spectrum of this matrix model Hamiltonian is estimated using standard variational methods, and is analyzed in the strong coupling limit. By employing a matching prescription to determine the dependence of the Yang-Mills coupling constant $g$ on $R$, we relate the asymptotic values of the energy eigenvalues in the $R\to \infty$ (flat space) limit to the masses of light hadrons. We find that the matrix model estimates the light hadron spectrum fairly accurately, with the light baryon masses falling within $10\%$, and most light meson masses falling within about $30\%$ of their observed values.

    ↳ hep-thhep-lathep-phPRD(2020)·11 citations
24. 24*

    Entanglement and the Infrared

    Gordon W. Semenoff🇨🇦

    We shall outline some results regarding the infrared catastrophes of quantum electrodynamics and perturbative quantum gravity and their implications for information loss in quantum processes involving electrically or gravitationally charged particles. We will argue that two common approaches to the solution of the infrared problem, using transition probabilities which are inclusive of copious soft photon and graviton production and using dressed states describe fundamentally different quantizations of electrodynamics and low energy gravity which are, in principle, distinguishable by experiments.

    ↳ hep-thhep-phquant-phSpringer Proc.Math.Stat.(2019)·12 citations
25. 25*

    Chirp effects on pair production in oscillating electric fields with spatial inhomogeneity

    Mamutjan Ababekri🇨🇳 · Sayipjamal Dulat🇨🇳 · B.S. Xie🇨🇳 · Jun Zhang🇨🇳

    Dirac-Heisenberg-Wigner formalism is used to study chirp effects on the vacuum pair creation under inhomogeneous electric fields. For rapidly oscillating electric fields, the particle momentum spectrum is sensitive to both of the spatial scale and the chirp parameter, and the external field width has less significant effect for the maximally large chirp. For slowly oscillating electric fields, chirp effects could be identified at large spatial extents and the carrier phase plays a significant role reflecting chirp effects even at small spatial scales. We also notice that, the local density approximation holds for all external field profiles considered in this work at the quasihomogeneous limit allowing one to use arguments from homogeneous scenarios to analyze inhomogeneous results.

    ↳ quant-phhep-phphysics.plasm-phPLB(2020)·24 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.