Mon·Feb 3, 2020Monday·February 3, 2020

1. 01*

   DES16C3cje: A low-luminosity, long-lived supernova

   C. P. Gutiérrez · M. Sullivan · L. Martinez · M. C. Bersten · C. Inserra · M. Smith · J. P. Anderson · Y.-C. Pan · A. Pastorello · L. Galbany · P. Nugent · C. R. Angus and 80 other authors

   We present DES16C3cje, a low-luminosity, long-lived type II supernova (SN II) at redshift 0.0618, detected by the Dark Energy Survey (DES). DES16C3cje is a unique SN. The spectra are characterized by extremely narrow photospheric lines corresponding to very low expansion velocities of $\lesssim 1500$ km s${}^{-1}$, and the light curve shows an initial peak that fades after 50 days before slowly rebrightening over a further 100 days to reach an absolute brightness of M${}_r\sim -15.5$ mag. The decline rate of the late-time light curve is then slower than that expected from the powering by radioactive decay of ${}^{56}$Co but is comparable to that expected from accretion power. Comparing the bolometric light curve with hydrodynamical models, we find that DES16C3cje can be explained by either i) a low explosion energy (0.11 foe) and relatively large ${}^{56}$Ni production of 0.075 M${}_{\odot }$ from a $\sim 15$ M${}_{\odot }$ red supergiant progenitor typical of other SNe II, or ii) a relatively compact $\sim 40$ M${}_{\odot }$ star, explosion energy of 1 foe, and 0.08 M${}_{\odot }$ of ${}^{56}$Ni. Both scenarios require additional energy input to explain the late-time light curve, which is consistent with fallback accretion at a rate of $\sim 0.5\times 10^{-8}$ M${}_{\odot }$ s${}^{-1}$.

   hep-phastro-ph.HEMNRAS(2020)·14 citations
2. 02*

   Chiral Condensate and Spectral Density at full five-loop and partial six-loop orders of Renormalization Group Optimized Perturbation

   Jean-Loic Kneur🇫🇷 · André Neveu🇫🇷

   We reconsider our former determination of the chiral quark condensate $⟨\bar{q}q⟩$ from the related QCD spectral density of the Euclidean Dirac operator, using our Renormalization Group Optimized Perturbation (RGOPT) approach. Thanks to the recently available {\em complete} five-loop QCD RG coefficients, and some other related four-loop results, we can extend our calculations exactly to $N^{4}LO$ (five-loops) RGOPT, and partially to $N^{5}LO$ (six-loops), the latter within a well-defined approximation accounting for all six-loop contents exactly predictable from five-loops RG properties. The RGOPT results overall show a very good stability and convergence, giving primarily the RG invariant condensate, $⟨\bar{q}q{⟩}_{RGI}^{1/3}(n_f=0)=-(0.840_{-0.016}^{+0.020}){\bar{\Lambda }}_0$, $⟨\bar{q}q{⟩}_{RGI}^{1/3}(n_f=2)=-(0.781_{-0.009}^{+0.019}){\bar{\Lambda }}_2$, $⟨\bar{q}q{⟩}_{RGI}^{1/3}(n_f=3)=-(0.751_{-.010}^{+0.019}){\bar{\Lambda }}_3$, where ${\bar{\Lambda }}_{n_f}$ is the basic QCD scale in the \overline{MS} scheme for $n_f$ quark flavors, and the range spanned is our rather conservative estimated theoretical error. This leads {\it e.g.} to $⟨\bar{q}q{⟩}_{n_f=3}^{1/3}(2\mathrm{GeV})=-(273_{-4}^{+7}\pm 13)$ MeV, using the latest ${\bar{\Lambda }}_3$ values giving the second uncertainties. We compare our results with some other recent determinations. As a by-product of our analysis we also provide complete five-loop and partial six-loop expressions of the perturbative QCD spectral density, that may be useful for other purposes.

   hep-phhep-latPRD(2020)·15 citations
3. 03*

   Pre-critical soft photons emission from quark matter

   B.O. Kerbikov🇷🇺

   We compute the soft real photon emission rate from the QCD matter in the vicinity of the critical line at moderate density and the temperature approaching the critical one from above. The obtained production rate exhibits a steep rise close to $T_c$ due to the formation of the slow fluctuation mode.

   hep-phnucl-thPRD(2020)·2 citations
4. 04*

   Momentum and its affiliated transport coefficients for a hot QCD matter in a strong magnetic field

   Shubhalaxmi Rath🇮🇳 · Binoy Krishna Patra🇮🇳

   We have studied the effects of anisotropies on the momentum transport in a QCD matter by shear ($\eta$) and bulk ($\zeta$) viscosities. The anisotropies arise either by the strong magnetic field or by the preferential expansion. This study helps to understand the fluidity and location of transition point of matter through $\eta /s$ and $\zeta /s$ ($s$ is entropy density), respectively, the sound attenuation through the Prandtl number (Pl), the nature of flow by the Reynolds number (Rl), and the competition between momentum and charge diffusions. The viscosities are calculated in the relaxation time approximation of kinetic theory within the quasiparticle model. Compared to isotropic medium, both $\eta$ and $\zeta$ get increased in magnetic field-driven (B-driven) anisotropy, contrary to the decrease in expansion-driven anisotropy. $\eta$ increases with temperature faster in former case than in latter case whereas $\zeta$ in former case decreases with temperature and in latter case, it is meagre and diminishes at a specific temperature. So the viscosities can distinguish aforesaid anisotropies. Thus, $\eta /s$ gets enhanced in former case and in latter case, it becomes smaller than isotropic one. Similarly $\zeta /s$ gets amplified but decreases faster with the temperature in a strong magnetic field. The Prandtl number gets increased in B-induced anisotropy and gets decreased in expansion-induced anisotropy, compared to isotropic one. Since, Pl is found larger than 1, the sound attenuation is governed by momentum diffusion. The B-driven anisotropy makes the Reynolds number smaller than one, whereas the expansion-driven anisotropy makes it larger. The ratio ($\frac{\eta }{s}/\frac{{\sigma }_{\mathrm{el}}}{T}$) gets amplified in B-driven anisotropy whereas it gets reduced in expansion-driven anisotropy. Since, the ratio is always more than one, the momentum diffusion prevails over the charge diffusion.

   hep-phhep-thnucl-thPRD(2020)·25 citations
5. 05*

   Wigner function and kinetic theory for massive spin-1/2 particles

   Nora Weickgenannt🇩🇪 · Xin-li Sheng🇨🇳 · Enrico Speranza🇩🇪 · Qun Wang🇨🇳 · Dirk H. Rischke🇩🇪

   We calculate the Wigner function for massive spin-1/2 particles in an inhomogeneous electromagnetic field to leading order in the Planck constant $\hslash$. Going beyond leading order in $\hslash$ we then derive a generalized Boltzmann equation in which the force exerted by an inhomogeneous electromagnetic field on the particle dipole moment arises naturally. Furthermore, a kinetic equation for this dipole moment is derived. Carefully taking the massless limit we find agreement with previous results. The case of global equilibrium with rotation is also studied. Our framework can be used to study polarization effects induced by vorticity and magnetic field in relativistic heavy-ion collisions.

   hep-phNPA(2021)·13 citations
6. 06*

   Heavy quark momentum diffusion coefficient in 3D gluon plasma

   K. Boguslavski🇦🇹 · A. Kurkela🇨🇭 · T. Lappi🇫🇮 · J. Peuron🇮🇹

   We study the heavy-quark momentum diffusion coefficient in far from equilibrium gluon plasma in a self-similar regime using real-time lattice techniques. We use 3 methods for the extraction: an unequal time electric field 2-point correlator integrated over the time difference, a spectral reconstruction (SR) method based on the measured equal time electric field correlator and a kinetic theory (KT) formula. The time-evolution of the momentum diffusion coefficient extracted using all methods is consistent with an approximate $t^{\frac{-1}{2}}$ power law. We also study the extracted diffusion coefficient as a function of the upper limit of the time integration and observe that including the infrared enhancement of the equal-time correlation function in the SR calculation improves the agreement with the data for transient time behavior considerably. This is a gauge invariant confirmation of the infrared enhancement previously observed only in gauge fixed correlation functions.

   hep-phhep-latNPA(2021)·5 citations
7. 07*

   Renormalon effects in top-mass sensitive observables

   Silvia Ferrario Ravasio🇬🇧

   A precise determination of the top mass is one of the key goals of the LHC and future colliders. Since power corrections are now becoming a source of worry for top-mass measurements, in these proceedings I discuss the impact of linear infrared renormalons, which plague the definition of the top pole-mass $m$, on observables expressed in terms of $m$ and in terms of a short-distance mass.

   hep-ph0 citations
8. 08*

   Impact of a thermal medium on $D$ mesons and their chiral partners

   Glòria Montaña🇪🇸 · Àngels Ramos🇪🇸 · Laura Tolos🇩🇪 · Juan M. Torres-Rincon🇩🇪

   We study $D$ and $D_s$ mesons at finite temperature using an effective field theory based on chiral and heavy-quark spin-flavor symmetries within the imaginary-time formalism. Interactions with the light degrees of freedom are unitarized via a Bethe-Salpeter approach, and the $D$ and $D_s$ self-energies are calculated self-consistently. We generate dynamically the $D_0^{\ast }(2300)$ and $D_s(2317)$ states, and study their possible identification as the chiral partners of the $D$ and $D_s$ ground states, respectively. We show the evolution of their masses and decay widths as functions of temperature, and provide an analysis of the chiral-symmetry restoration in the heavy-flavor sector below the transition temperature. In particular, we analyse the very special case of the $D$-meson, for which the chiral partner is associated to the double-pole structure of the $D_0^{\ast }(2300)$.

   hep-phnucl-thPLB(2020)·43 citations
9. 09*

   A few topics in BFKL phenomenology at hadron colliders

   Agustín Sabio Vera🇪🇸

   This is a personal recollection of several results involving the phenomenological study of the multi-Regge limit of scattering amplitudes. None of them would have been possible without the encouragement and constant support from Lev Nikolaevich Lipatov.

   hep-ph1 citation
10. 10*

    Chiral Abelian gauge theories with few fermions

    Davi B. Costa🇧🇷 · Bogdan A. Dobrescu🇺🇸 · Patrick J. Fox🇺🇸

    We construct chiral theories with the smallest number $n_{\chi }$ of Weyl fermions that form an anomaly-free set under various Abelian gauge groups. For the $U(1)$ group, where $n_{\chi }=5$, we show that the general solution to the anomaly equations is a set of charges given by cubic polynomials in three integer parameters. For the $U(1)\times U(1)$ gauge group we find $n_{\chi }=6$, and derive the general solution to the anomaly equations, in terms of 6 parameters. For $U(1)\times U(1)\times U(1)$ we show that $n_{\chi }=8$, and present some families of solutions. These chiral gauge theories have potential applications to dark matter models, right-handed neutrino interactions, and other extensions of the Standard Model. As an example, we present a simple dark sector with a natural mass hierarchy between three dark matter components.

    hep-phhep-thmath.NTPRD(2020)·27 citations
11. 11*

    Das ist der HAMMER: Consistent new physics interpretations of semileptonic decays

    Florian U. Bernlochner🇩🇪 · Stephan Duell🇩🇪 · Zoltan Ligeti🇺🇸 · Michele Papucci🇺🇸 · Dean J. Robinson🇺🇸

    Precise measurements of $b\to c\tau \bar{\nu }$ decays require large resource-intensive Monte Carlo (MC) samples, which incorporate detailed simulations of detector responses and physics backgrounds. Extracted parameters may be highly sensitive to the underlying theoretical models used in the MC generation. Because new physics (NP) can alter decay distributions and acceptances, the standard practice of fitting NP Wilson coefficients to SM-based measurements of the $R(D^{(\ast )})$ ratios can be biased. The newly developed HAMMER software tool enables efficient reweighting of MC samples to arbitrary NP scenarios or to any hadronic matrix elements. We demonstrate how HAMMER allows avoidance of biases through self-consistent fits directly to the NP Wilson coefficients. We also present example analyses that demonstrate the sizeable biases that can otherwise occur from naive NP interpretations of SM-based measurements. The HAMMER library is presently interfaced with several existing experimental analysis frameworks and we provide an overview of its structure.

    hep-phhep-exEPJC(2020)·71 citations
12. 12*

    On the Comparison of AGN with GRMHD Simulations: I. Sgr A*

    Richard Anantua🇺🇸 · Sean Ressler🇺🇸 · Eliot Quataert🇺🇸

    We present models of Galactic Center emission in the vicinity of Sagittarius A* that use parametrizations of the electron temperature or energy density. These models include those inspired by two-temperature general relativistic magnetohydrodynamic (GRMHD) simulations as well as jet-motivated prescriptions generalizing equipartition of particle and magnetic energies. From these models, we calculate spectra and images and classify them according to their distinct observational features. Some models produce morphological and spectral features, e.g., image sizes, the sub-mm bump and low frequency spectral slope compatible with observations. Models with spectra consistent with observations produce the most compact images, with the most prominent, asymmetric photon rings. Limb brightened outflows are also visible in many models. Of all the models we consider, that which represents the current data the best is one in which electrons are relativistically hot when magnetic pressure is larger than the thermal pressure, but cold (i.e., negligibly contributing to the emission) otherwise. This work is part of a series also applying the "observing" simulations methodology to near-horizon regions of supermassive black holes in M87 and 3C 279.

    ↳ astro-ph.HEhep-phMNRAS(2020)·34 citations
13. 13*

    Radial distribution of charm quarks in jets in high-energy heavy-ion collisions

    Sa Wang🇨🇳 · Wei Dai🇨🇳 · Jun Yan🇨🇳 · Ben-Wei Zhang🇨🇳 · Enke Wang🇨🇳

    Heavy flavor physics in high-energy heavy-ion collisions is a promising and active area to study the mass dependence of the "jet quenching" effects both at the RHIC and the LHC. In this talk, we present the first theoretical study on the $D^0$ meson radial distributions relative to the jet axis both in p+p and Pb+Pb collisions at $\sqrt{s_{NN}}=5.02$ TeV, where a nice agreement of our results with experimental data is observed. The in-medium parton propagations are described by a Monte Carlo transport model which uses the next-to-leading order (NLO) plus parton shower (PS) event generator SHERPA as input and includes elastic (collisional) and inelastic (radiative) in-medium interaction of heavy flavor jet. We find that, at low $D^0$ meson $p_T$, the radial distribution significantly shifts to larger radius indicating a strong diffusion effect, and the diffusion effects decrease quickly with $p_T$ ,which is consistent with the recent CMS measurements. We demonstrate that the angular deviation of charm quarks is sensitive to $D_s$ but not $\hat{q}$, which may provide new constrains on the collisional and radiative heavy quark energy loss.

    ↳ nucl-thhep-phNPA(2021)·11 citations
14. 14*

    Study of intermediate states in the inclusive semileptonic $B\to X_{c}l\nu$ decay structure function

    G. Bailas🇯🇵 · S. Hashimoto🇯🇵 · T. Kaneko🇯🇵 · J. Koponen🇯🇵

    We analyze the inclusive semileptonic $B\to X_c\ell \nu$ structure functions in 2+1-flavor lattice QCD. The Möbius domain-wall fermion action is used for light, strange, charm and bottom quarks. The structure function receives contributions from various exclusive modes, including the dominant S-wave states $D_s^{(\ast )}$ as well as the P-wave states $D_s^{\ast \ast }$. We can identify them in the lattice data, from which we put some constraints on the $B_s\to D_s^{\ast \ast }\ell \nu$ form factors.

    ↳ hep-lathep-phPoS(2019)·6 citations
15. 15*

    Reconstruction of smeared spectral function from Euclidean correlation functions

    Gabriela Bailas🇯🇵 · Shoji Hashimoto🇯🇵 · Tsutomu Ishikawa🇯🇵

    We propose a method to reconstruct smeared spectral functions from two-point correlation functions measured on the Euclidean lattice. Arbitrary smearing function can be considered as far as it is smooth enough to allow an approximation using Chebyshev polynomials. We test the method with numerical lattice data of Charmonium correlators. The method provides a framework to compare lattice calculation with experimental data including excited state contributions without assuming quark-hadron duality.

    ↳ hep-lathep-phPTEP(2020)·72 citations
16. 16*

    Beauty 2019 -- Conference summary

    Patrick Koppenburg🇳🇱

    Some highlights from the 18${}^{\mathrm{th}}$ international conference on $B$ physics at frontier machines are presented, including first results from the full LHC Run 2 data and from early Belle II data.

    ↳ hep-exhep-phPoS(2020)·1 citation
17. 17*

    Planckian hypersurfaces, inflation and bounces

    Massimo Giovannini🇨🇭

    When the different wavelengths of the scalar and tensor modes of the geometry are all assigned on the same space-like hypersurface the maximally amplified frequencies of the spectrum remain smaller than the Planck mass only if the duration of a stage of accelerated expansion and the corresponding tensor to scalar ratio are severely constrained. All the different wavelengths can be initialized on the same space-like hypersurface at the onset of inflation but this strategy and the related conclusions are plausible only for classical inhomogeneities. We argue that a whole class of potential constraints is easily evaded provided the different wavelengths of the quantum fields are assigned as soon as they cross the corresponding Planckian hypersurfaces. In this case the Cauchy data for the mode functions depend on the wavenumber so that larger wavelengths start evolving earlier while shorter wavelengths are assigned later. Within this strategy the duration of a conventional inflationary phase and the corresponding tensor to scalar ratio are not constrained but the large-scale power spectra inherit specific large-scale corrections that remain however unobservable.

    ↳ hep-thastro-ph.COgr-qchep-phEPJC(2020)·1 citation
18. 18*

    Studying QGP with flow: A theory overview

    Chun Shen🇺🇸

    I review recent developments in the phenomenological study of the quark-gluon plasma (QGP) transport properties based on a personal selection of results that were presented at Quark Matter 2019. The constraints on the temperature dependence of QGP shear and bulk viscosity are summarized. I discuss new theory advancements towards more realistic 3D dynamical simulations of heavy-ion collisions at finite baryon density. The challenges and opportunities of applying hydrodynamics to small collision systems are highlighted.

    ↳ nucl-thhep-phnucl-exNPA(2021)·50 citations
19. 19*

    PT-Symmetric Non-Hermitian Quantum Field Theories with Supersymmetry

    Jean Alexandre🇬🇧 · John Ellis🇬🇧 · Peter Millington🇬🇧

    We formulate supersymmetric non-Hermitian quantum field theories with PT symmetry, starting with free chiral boson/fermion models and then including trilinear superpotential interactions. We consider models with both Dirac and Majorana fermions, analyzing them in terms of superfields and at the component level. We also discuss the relation between the equations of motion, the (non-)invariance of the Lagrangian and the (non-)conservation of the supercurrents in the two models. We exhibit a similarity transformation that maps the free-field supersymmetric PT-symmetric Dirac model to a supersymmetric Hermitian theory, but there is, in general, no corresponding similarity transformation for the Majorana model. In this model, we find generically a mass splitting between bosons and fermions, even though its construction is explicitly supersymmetric, offering a novel non-Hermitian mechanism for soft supersymmetry breaking.

    ↳ hep-thhep-phPRD(2020)·31 citations
20. 20*

    Photon-Photon Scattering in Very Special Relativity

    Jorge Alfaro🇨🇱 · Alex Soto🇨🇱

    Starting from the Mandelstam-Leibbrandt prescription, we introduce a general rule for the null vector $\bar{n}$ to compute any $SIM(2)$ integral and diagram with an arbitrary number of external legs. Using the new prescription, the computation of the low energy limit of photon-photon scattering under the Very Special Relativity (VSR) framework is presented. The prescription preserves automatically the Ward identities corresponding to the gauge symmetry. Within the low momentum approximation we get the standard unpolarized differential cross section for photon-photon scattering. The result suggests that loops with any external photon legs on-shell will be zero in VSR.

    ↳ hep-thhep-ph3 citations
21. 21*

    First search for dyons with the full MoEDAL trapping detector in 13 TeV pp collisions

    B. Acharya🇬🇧 · J. Alexandre🇬🇧 · P. Benes🇨🇿 · B. Bergmann🇨🇿 · J. Bernabeu🇪🇸 · A. Bevan🇬🇧 · H. Branzas🇷🇴 · P. Burian🇨🇿 · M. Campbell🇨🇭 · S. Cecchini🇮🇹 · Y. M. Cho🇰🇷 · M. de Montigny🇨🇦 and 57 other authors

    The MoEDAL trapping detector, consists of approximately 800 kg of aluminium volumes. It was exposed during Run-2 of the LHC program to 6.46 fb^-1 of 13 TeV proton-proton collisions at the LHCb interaction point. Evidence for dyons (particles with electric and magnetic charge) captured in the trapping detector was sought by passing the aluminium volumes comprising the detector through a SQUID magnetometer. The presence of a trapped dyon would be signalled by a persistent current induced in the SQUID magnetometer. On the basis of a Drell-Yan production model, we exclude dyons with a magnetic charge ranging up to 5 Dirac charges, and an electric charge up to 200 times the fundamental electric charge for mass limits in the range 790 - 3130 GeV.

    ↳ hep-exhep-phPRL(2021)·62 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.