Mon·Nov 25, 2019Monday·November 25, 2019

1. 01*

   Topic Model for four-top at the LHC

   Ezequiel Alvarez🇦🇷 · Federico Lamagna🇦🇷 · Manuel Szewc🇦🇷

   We study the implementation of a Topic Model algorithm in four-top searches at the LHC as a test-probe of a not ideal system for applying this technique. We study this Topic Model behavior as its different hypotheses such as mutual reducibility and equal distribution in all samples shift from true. The four-top final state at the LHC is not only relevant because it does not fulfill these conditions, but also because it is a difficult and inefficient system to reconstruct and current Monte Carlo modeling of signal and backgrounds suffers from non-negligible uncertainties. We implement this Topic Model algorithm in the Same-Sign lepton channel where S/B is of order one and all backgrounds cannot have more than two b-jets at parton level. We define different mixtures according to the number of b-jets and we use the total number of jets to demix. Since only the background has an anchor bin, we find that we can reconstruct the background in the signal region independently of Monte Carlo. We propose to use this information to tune the Monte Carlo in the signal region and then compare signal prediction with data. We also explore Machine Learning techniques applied to this Topic Model algorithm and find slight improvements as well as potential roads to investigate. Although our findings indicate that still with the full LHC run 3 data the implementation would be challenging, we pursue through this work to find ways to reduce the impact of Monte Carlo simulations in four-top searches at the LHC.

   hep-phhep-exJHEP(2020)·17 citations
2. 02*

   Escalating core formation with dark matter self-heating

   Ayuki Kamada🇰🇷 · Hee Jung Kim🇰🇷

   Exothermic scatterings of dark matter (DM) produce DM particles with significant kick velocities inside DM halos. In collaboration with DM self-interaction, the excess kinetic energy of the produced DM particles is distributed to the others, which self-heats the DM particles as a whole. The DM self-heating is efficient towards the halo center, and the heat injection is used to enhance the formation of a uniform density core inside halos. The effect of DM self-heating is expected to be more significant in smaller halos for two reasons: 1) the exothermic cross section times the relative velocity, $⟨{\sigma }_{\mathrm{exo}}{v}_{\mathrm{rel}}⟩$, is constant; 2) and the ratio of the injected heat to the velocity dispersion squared gets larger towards smaller halos. For the first time, we quantitatively investigate the core formation from DM self-heating for halos in a wide mass range ($10^9$-$10^{15}{\mathrm{M}}_{\odot }$) using the gravothermal fluid formalism. Notably, we demonstrate that the core formation is sharply escalating towards smaller halos by taking the self-heating DM (i.e., DM that semi-annihilates and self-interacts) as an example. We show that the sharp escalation of core formation may cause a tension in simultaneously explaining the observed central mass deficit of Milky Way satellites, and field dwarf/low surface brightness spiral galaxies. While the details of the self-heating effect may differ among models, we expect that the sharp halo-mass dependence of the core formation is a general feature of exothermic DM.

   hep-phastro-ph.COastro-ph.GAPRD(2020)·20 citations
3. 03*

   Large Effects from Small QCD Instantons: Making Soft Bombs at Hadron Colliders

   Valentin V. Khoze🇬🇧 · Frank Krauss🇬🇧 · Matthias Schott🇩🇪

   It is a common belief that the last missing piece of the Standard Model of particles physics was found with the discovery of the Higgs boson at the Large Hadron Collider. However, there remains a major prediction of quantum tunnelling processes mediated by instanton solutions in the Yang-Mills theory, that is still untested in the Standard Model. The direct experimental observation of instanton-induced processes, which are a consequence of the non-trivial vacuum structure of the Standard Model and of quantum tunnelling in QFT, would be a major breakthrough in modern particle physics. In this paper, we present for the first time a full calculation of QCD instanton-induced processes in proton-proton collisions accounting for quantum corrections due to both initial and final state gluon interactions, a first implementation in an MC event generator as well as a basic strategy how to observe these effects experimentally.

   hep-phhep-thJHEP(2020)·28 citations
4. 04*

   Probing the linearly polarized gluons in unpolarized proton with heavy-quark pair production

   N.Ya. Ivanov🇷🇺 · A.V. Efremov🇷🇺 · O.V. Teryaev🇷🇺

   We consider the azimuthal $\cos \phi$ and $\cos 2\phi$ distributions and the Callan-Gross ratio $R=\mathrm{d}{\sigma }_L/\mathrm{d}{\sigma }_T$ in heavy-quark pair electroproduction, $lN\to l^{\prime }Q\bar{Q}X$, as probes of linearly polarized gluons in unpolarized nucleons. Our analysis shows that the azimuthal asymmetries and Callan-Gross ratio are predicted to be large and very sensitive to the contribution of the gluonic counterpart of the Boer-Mulders function, $h_1^{\perp g}$, describing the linear polarization of gluons inside unpolarized nucleon. In particular, the maximum values of the azimuthal distributions vary from 0 to 1 depending on $h_1^{\perp g}$. We conclude that future measurements of these quantities at the proposed EIC and LHeC colliders could clarify in details the proton spin decomposition puzzle.

   hep-phJ.Phys.Conf.Ser.(2020)·0 citations
5. 05*

   Nature of the vector resonance $Y(2175)$

   S. S. Agaev🇦🇿 · K. Azizi🇮🇷 · H. Sundu🇹🇷

   Spectroscopic parameters and decay channels of the vector resonance $Y(2175)$ are studied by considering it as a diquark-antidiquark state with the quark content $su\overline{s}\overline{u}$. The mass and coupling of the tetraquark $Y(2175)$ are calculated using the QCD two-point sum rules by taking into account various quark, gluon and mixed condensates up to dimension 15. Partial widths of its strong decays to $\varphi f_0(980)$, $\varphi \eta$, and $\varphi {\eta }^{\prime }$ are computed as well. To this end, we explore the vertices $Y\varphi f_0(980)$, $Y\varphi \eta$, and $Y\varphi {\eta }^{\prime }$, and calculate the corresponding strong couplings by means of the QCD light-cone sum rule method. The coupling $G_{Y\varphi f}$ of the vertex $Y\varphi f_0(980)$ is found using the full version of this method, and by treating the scalar meson $f_0(980)$ as a diquark-antidiquark tetraquark state. The couplings $g_{Y\varphi \eta }$ and $g_{Y\varphi {\eta }^{\prime }}$, however, are calculated by applying the soft-meson approximation to the light-cone sum rule method. Prediction for the mass of the resonance $m_Y=\left(2173\pm 85\right)\mathrm{MeV}$ is in excellent agreement with the data of the BaBar Collaboration \cite{Aubert:2006bu}, and within errors of calculations is compatible with the result reported by BESIII \cite {Ablikim:2014pfc}. The full width ${\Gamma }_{\mathrm{full}}=(91.1\pm 20.5)\mathrm{MeV}$ of the $Y(2175)$ saturated by its three strong decay channels is in a reasonable agreement with existing experimental data.

   hep-phhep-exhep-latPRD(2020)·39 citations
6. 06*

   Stability of neutral minima against charge breaking in the Higgs triplet model

   P.M. Ferreira🇵🇹 · B.L. Gonçalves🇵🇹

   We analyse the possibility of charge breaking minima developing in the Higgs triplet model, and under what conditions they are deeper than charge-preserving ones. Analytical expressions relating the depth of minima of different types are deduced. A global symmetry of the model leads to increased stability for charge-preserving vacua. However, if that symmetry is broken by a soft term, deeper charge-breaking minima may occur more easily. We identify the vev configurations most likely to produce charge breaking minima.

   hep-phJHEP(2020)·14 citations
7. 07*

   Spectral swaps in a two-dimensional neutrino ring model

   Joshua D. Martin🇺🇸 · J. Carlson🇺🇸 · Huaiyu Duan🇺🇸

   Neutrinos emitted deep within a supernova explosion experience a self-induced index of refraction. In the stationary, one-dimensional (1D) supernova "bulb model", this self-induced refraction can lead to a collective flavor transformation which is coherent among different neutrino momentum modes. Such collective oscillations can produce partial swaps of the energy spectra of different neutrino species as the neutrinos stream away from the proto-neutron star. However, it has been demonstrated that the spatial symmetries (such as the spherical symmetry in the bulb model) can be broken spontaneously by collective neutrino oscillations in multi-dimensional models. Using a stationary, 2D neutrino ring model we demonstrate that there exist two limiting scenarios where collective oscillations may occur. In one limit, the collective flavor transformation begins at a radius with relatively high neutrino densities and develops small-scale flavor structures. The loss of the spatial correlation in the neutrino flavor field results in similar (average) energy spectra for the anti-neutrinos of almost all energies and the neutrinos of relatively high energies. In the other limit, the flavor transformation starts at a radius where the neutrino densities are smaller (e.g., due to the suppression of the high matter density near the proto-neutron star). Although the spatial symmetry is broken initially, it is restored as the neutrino densities decrease, and the neutrinos of different flavors partially swap their energy spectra as in the 1D bulb model. This finding may have interesting ramifications in other aspects of supernova physics.

   hep-phastro-ph.HEnucl-thPRD(2020)·22 citations
8. 08*

   Interplay between nonstandard and nuclear constraints in coherent elastic neutrino-nucleus scattering experiments

   B. C. Canas🇨🇴 · E. A. Garces🇲🇽 · O. G. Miranda🇲🇽 · A. Parada🇨🇴 · G. Sanchez Garcia🇲🇽

   New measurements of the coherent elastic neutrino-nucleus scattering (CEvNS) are expected to be achieved in the near future by using two neutrino production channels with different energy distributions: the very low energy electron antineutrinos from reactor sources and the muon and electron neutrinos from spallation neutron sources (SNS) with a relatively higher energy. Although precise measurements of this reaction would allow an improved knowledge of standard and beyond the Standard Model physics, it is important to distinguish the different new contributions to the process. We illustrate this idea by constraining the average neutron root mean square (rms) radius of the scattering material, as a standard physics parameter, together with the nonstandard interactions (NSI) contribution as the new physics formalism. We show that the combination of experiments with different neutrino energy ranges could give place to more robust constraints on these parameters as long as the systematic errors are under control.

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

   Dynamical Breaking to Special or Regular Subgroups in $SO(N)$ Nambu--Jona-Lasinio Model

   Taichiro Kugo🇯🇵 · Naoki Yamatsu🇯🇵

   It is recently shown that in 4D $SU(N)$ Nambu--Jona-Lasinio (NJL) type models, the $SU(N)$ symmetry breaking into its special subgroups is not special but much more common than that into the regular subgroups, where the fermions belong to complex representations of $SU(N)$. We perform the same analysis for $SO(N)$ NJL model for various $N$ with fermions belonging to an irreducible spinor representation of $SO(N)$. We find that the symmetry breaking into special or regular subgroups has some correlation with the type of fermion representations; i.e., complex, real, pseudo-real representations.

   hep-phhep-thPTEP(2020)·3 citations
10. 10*

    Quark fluctuations and anisotropic confinement in magnetic fields

    Gaoqing Cao🇨🇳 · Toru Kojo🇨🇳

    We study the string tension $\sigma$ of quantum chromodynamics (QCD) in external magnetic fields $B$ by combining the quasi-particle treatments for quarks with the collective treatments for gluons. We utilize the 1/Nc-expansion (Nc: number of colors) and the framework of Wilson's strong coupling expansion at long distance, and compare the resulting string tensions with the lattice data. The effects of magnetic fields are taken into account through the dielectric functions, which are evaluated from the one-loop polarization due to light flavor quarks with $B$-dependent effective masses $M_{\mathrm{f}}(B)(\mathrm{f}=u,d,s)$. All Landau levels are adopted in the calculations so that we can explore the string tensions from weak to strong magnetic fields. For the effective quark masses, we use a simple parameterization: $M_{\mathrm{f}}(B)=M_{\mathrm{f}}(0)+C_B|q_{\mathrm{f}}B{|}^{1/2}$ with $q_{\mathrm{f}}$ the electric charge of a given flavor and $C_B$ an adaptive parameter. We find that the parameter $C_B$ needs to be small, $C_B\lesssim 0.05$, to qualitatively reproduce the trends of lattice QCD results for $0\le |eB|\lesssim 1.5{\mathrm{GeV}}^2$. The quantitative agreement is found for $C_B\simeq 0$ and the strong coupling ${\alpha }_S\simeq 5$ in the infrared.

    hep-phhep-lathep-thnucl-th3 citations
11. 11*

    Tetraquark mixing framework to explain two light-meson nonets

    Hungchong Kim🇰🇷

    In this talk, we summarize our recent works on the tetraquark mixing framework for the two light-meson nonets in the $J^{PC}=0^{++}$ channel, the light nonet [$a_0(980)$, $K_0^{\ast }(700)$, $f_0(500)$, $f_0(980)$] and the heavy nonet [$a_0(1450)$, $K_0^{\ast }(1430)$, $f_0(1370)$, $f_0(1500)$]. We briefly explain this mixing framework and present various phenomenological signatures to support this picture.

    hep-phhep-exnucl-th3 citations
12. 12*

    Anisotropic electrical conductivity of magnetized hot quark matter

    Sabyasachi Ghosh🇮🇳 · Aritra Bandyopadhyay🇧🇷 · Ricardo L. S. Farias🇧🇷 · Jayanta Dey🇮🇳 · Gastão Krein🇧🇷

    We studied the effect of a strong magnetic field ($B$) on the electrical conductivity of hot quark matter. The electrical conductivity is a key transport coefficient determining the time dependence and strength of magnetic fields generated in a relativistic heavy-ion collision. A~magnetic field induces Hall anisotropic conduction, phase-space Landau-level quantization and, if sufficiently strong, interferes with prominent QCD phenomena such as dynamical quark mass generation, likely affecting the quark matter electrical conductivity, which depends strongly on the quark masses. To address these issues, we used a quasi-particle description of quark matter in which the electric charge carriers are constituent quarks with temperature- and magnetic-field-dependent masses predicted by a Nambu--Jona-Lasinio model. The model accurately describes recent lattice QCD results showing magnetic catalysis at low temperatures and inverse magnetic catalysis at temperatures close to the pseudo-critical temperature ($T_{\mathrm{pc}}$) of the QCD phase transition. We found that the magnetic field increases the conductivity component parallel to it and decreases the transverse component, in qualitative agreement with recent lattice QCD results. In addition, we found that: (1)~the space anisotropy of the conductivity increases with~$B$, (2)~the longitudinal conductivity increases due to phase-space Landau-level quantization, (3)~a lowest Landau level approximation behaves poorly for temperatures close to $T_{\mathrm{pc}}$, and (5)~inverse magnetic catalysis leaves a distinctive signal in all components of the conductivity, a prominent peak at $T_{\mathrm{pc}}$. Our study adds to the existing body of work on the hot quark matter electrical conductivity by incorporating nontrivial temperature and magnetic field effects on dynamical mass generation.

    hep-phnucl-thPRD(2020)·49 citations
13. 13*

    Helicity amplitudes for generic multi-body particle decays featuring multiple decay chains

    Daniele Marangotto🇮🇹

    We present the general expression of helicity amplitudes for generic multi-body particle decays characterised by multiple decay chains. This is achieved by addressing for the first time the issue of the matching of final particle spin states among different decay chains in full generality for generic multi-body decays, proposing a method able to match the exact definition of spin states relative to the decaying particle ones. We stress the importance of our result by showing that one of the matching method used in the literature is incorrect, leading to amplitude models violating rotational invariance. The results presented are therefore relevant for performing numerous amplitude analysis, notably those searching for exotic structures like pentaquarks.

    hep-phAdv.High Energy Phys.(2020)·17 citations
14. 14*

    Using low energy atmospheric neutrinos for precision measurement of the mixing parameters

    Hisakazu Minakata🇺🇸 · Ivan Martinez-Soler🇺🇸 · Kimihiro Okumura🇯🇵

    Use of low energy atmospheric neutrinos is considered for precision measurement of neutrino mixing parameters. At around energy $E\simeq$ a few $\times$100 MeV and baseline $L$ of a few $\times$1000 km, CP phase effect is $\sim$10 times larger than that of the conventional LBL accelerator neutrino experiments. We report here a few progresses: (1) To analyze physics in the region, a new perturbative framework at around the solar-scale enhancement is developed. (2) To know the characteristic features of CP $\delta$ dependence of the atmospheric neutrinos at low energies, we plot the ratio of the ${\nu }_e$ and ${\bar{\nu }}_e$ fluxes $F(\delta )/F(\delta =0)$ for $\delta =\pm \frac{\pi }{2}$ and $\pi$ as a function of $E$ using the Honda {\it et al.} flux. Interestingly, it shows $\delta$ dependence of $\simeq$5-10\% level, with positive (negative) sign for ${\nu }_e$ (${\bar{\nu }}_e$). (3) To reduce the flux systematic errors, measurement of muon energy distribution around $\sim$1 GeV at high altitude may be useful. Water Cherenkov or muon range detectors may be the options with advantage in the latter if it is magnetized in view of the $\delta$ dependence of the flux.

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

    New Series Representations for the Two-Loop Massive Sunset Diagram

    B. Ananthanarayan🇮🇳 · Samuel Friot🇫🇷 · Shayan Ghosh🇩🇪

    We derive new convergent series representations for the two-loop sunset diagram with three different propagator masses m1, m2 and m3 and external momentum p by techniques of analytic continuation on a well-known triple series that corresponds to the Lauricella Fc function. The convergence regions of the new series contain regions of interest to physical problems. These include some ranges of masses and squared external momentum values which make them useful from Chiral Perturbation Theory to some regions of the parameter space of the Minimal Supersymmetric Standard Model. The analytic continuation results presented on the Lauricella series could be used in other settings as well.

    hep-phEPJC(2020)·21 citations
16. 16*

    Drell-Yan production with the CCFM-K evolution

    Krzysztof Golec-Biernat🇵🇱 · Tomasz Stebel🇵🇱

    We discuss the Drell-Yan dilepton production using the transverse momentum dependent parton distributions evolved with the Catani-Ciafaloni-Fiorani-Marchesini-Kwieciński (CCFM-K) equations in the single loop approximation. Such equations are obtained assuming angular ordering of emitted partons (coherence) for $x\sim 1$ and transverse momentum ordering for $x\ll 1$. This evolution scheme also contains the Collins-Soper-Sterman (CSS) soft gluon resummation. We make a comparison with a broad class of data on transverse momentum spectra of low mass Drell-Yan dileptons.

    hep-phEPJC(2020)·8 citations
17. 17*

    Estimation of Baryon Asymmetry from Dark Matter Decaying into IceCube Neutrinos

    Tista Mukherjee🇮🇳 · Madhurima Pandey🇮🇳 · Debasish Majumdar🇮🇳 · Ashadul Halder🇮🇳

    The recent results of IceCube Neutrino Observatory include an excess of PeV neutrino events which appear to follow a broken power law different from the other lower energy neutrinos detected by IceCube. The possible astrophysical source of these neutrinos is still unknown. One possible source of such neutrinos could be the decay of non-thermal, long-living heavy mass Dark Matter, whose mass should be $>10^6\mathrm{GeV}$ and could have produced at the very early Universe. They can undergo cascading decay via both hadronic and leptonic channels to finally produce such high energy neutrinos. This possibility has been explored in this work by studying the decay flux of these Dark Matter candidates. The mass and lifetime of such Dark Matter particles have been obtained by performing a ${\chi }^2$ fit with the PeV neutrino data of IceCube. We finally estimate the baryon asymmetry produced in the Universe due to such Dark Matter decay.

    hep-phInt.J.Mod.Phys.A(2021)·3 citations
18. 18*

    The $q_T$ subtraction method: electroweak corrections and power suppressed contributions

    Luca Buonocore🇨🇭 · Massimiliano Grazzini🇨🇭 · Francesco Tramontano🇮🇹

    Building upon the formulation of transverse-momentum resummation for heavy-quark hadroproduction, we present the first application of the $q_T$ subtraction formalism to the computation of electroweak corrections to massive lepton pairs through the Drell-Yan mechanism. We then study the power suppressed contributions to the $q_T$ subtraction formula in the parameter $r_{cut}$, defined as the minimum transverse momentum of the lepton pair normalised to its invariant mass. We analytically compute the leading power correction from initial and final-state radiation to the inclusive cross section. In the case of initial-state radiation the power correction is quadratic in $r_{cut}$ and our analytic result is consistent with results previously obtained in the literature. Final-state radiation produces linear contributions in $r_{cut}$ that may challenge the efficiency of the $q_T$ subtraction procedure. We explicitly compute the linear power correction in the case of the inclusive cross section and we discuss the extension of our calculation to differential distributions.

    hep-phhep-thEPJC(2020)·52 citations
19. 19*

    Exotic Vector-Like Quark Phenomenology in the Minimal Linear $\sigma$ Model

    J.A. Aguilar-Saavedra🇪🇸 · J. Alonso-Gonzalez🇪🇸 · L. Merlo🇪🇸 · J.M. No🇪🇸

    Extensions of the Standard Model that include vector-like quarks commonly also include additional particles that may mediate new production or decay modes. Using as example the minimal linear $\sigma$ model, that reduces to the minimal $SO(5)/SO(4)$ composite Higgs model in a specific limit, we consider the phenomenology of vector-like quarks when a scalar singlet $\sigma$ is present. This new particle may be produced in the decays $T\to t\sigma$, $B\to b\sigma$, where $T$ and $B$ are vector-like quarks of charges $2/3$ and $-1/3$, respectively, with subsequent decay $\sigma \to W^{+}{W}^{-},ZZ,hh$. By scanning over the allowed parameter space we find that these decays may be dominant. In addition, we find that the presence of several new particles allows for single $T$ production cross sections larger than those expected in minimal models. We discuss the observability of these new signatures in existing searches.

    hep-phhep-exPRD(2020)·41 citations
20. 20*

    Light Scalars and the KOTO Anomaly

    Daniel Egana-Ugrinovic🇨🇦 · Samuel Homiller🇺🇸 · Patrick Meade🇺🇸

    The KOTO experiment recently presented a significant excess of events in their search for the rare SM process $K_L\to {\pi }^0\nu \bar{\nu }$, well above both Standard Model signal and background predictions. We show that this excess may be due to weakly-coupled scalars that are produced from Kaon decays and escape KOTO undetected. We study two concrete realizations, the minimal Higgs portal and a hadrophilic scalar model, and demonstrate that they can explain the observed events while satisfying bounds from other flavor and beam-dump experiments. Hadronic beam-dump experiments provide particularly interesting constraints on these types of models, and we discuss in detail the normally underestimated uncertainties associated with them. The simplicity of the models which can explain the excess, and their possible relations with interesting UV constructions, provides strong theoretical motivation for a new physics interpretation of the KOTO data.

    hep-phPRL(2020)·104 citations
21. 21*

    Electroweak phase transition with spontaneous $Z_2$-breaking

    Marcela Carena🇺🇸 · Zhen Liu🇺🇸 · Yikun Wang🇺🇸

    This work investigates a simple, representative extension of the Standard Model with a real scalar singlet and spontaneous $Z_2$ breaking, which allows for a strongly first-order phase transition, as required by electroweak baryogenesis. We perform analytical and numerical calculations that systematically include one-loop thermal effects, Coleman-Weinberg corrections, and daisy resummation, as well as evaluation of bubble nucleation. We study the rich thermal history and identify the conditions for a strongly first-order electroweak phase transition with nearly degenerate extrema at zero temperature. This requires a light scalar with mass below 50 GeV. Exotic Higgs decays, as well as Higgs coupling precision measurements at the LHC and future collider facilities, will test this model. Additional information may be obtained from future collider constraints on the Higgs self-coupling. Gravitational-wave signals are typically too low to be probed by future gravitational wave experiments.

    hep-phJHEP(2020)·112 citations
22. 22*

    Exotic Higgs Decays and the Electroweak Phase Transition

    Jonathan Kozaczuk🇺🇸 · Michael J. Ramsey-Musolf🇺🇸 · Jessie Shelton🇺🇸

    Light new physics weakly coupled to the Higgs can induce a strong first-order electroweak phase transition (EWPT). Here, we argue that scenarios in which the EWPT is driven first-order by a light scalar with mass between $\sim 10$ GeV - $m_h/2$ and small mixing with the Higgs will be conclusively probed by the high-luminosity LHC and future Higgs factories. Our arguments are based on analytic and numerical studies of the finite-temperature effective potential and provide a well-motivated target for exotic Higgs decay searches at the LHC and future lepton colliders.

    hep-phastro-ph.COhep-exPRD(2020)·84 citations
23. 23*

    Top Quark Mass Effects in Next-To-Next-To-Next-To-Leading Order Higgs Boson Production: Virtual Corrections

    Joshua Davies🇩🇪 · Florian Herren🇩🇪 · Matthias Steinhauser🇩🇪

    We compute four-loop corrections to the Higgs boson gluon vertex, including finite top quark mass effects. Analytic results are presented which serve as a building block for the next-to-next-to-next-to-leading order corrections to Higgs boson production at the Large Hadron Collider at CERN.

    hep-phPRL(2020)·17 citations
24. 24*

    Gravitational waves from SGRs and AXPs as fast-spinning white dwarfs

    Manoel F. Sousa🇧🇷 · Jaziel G. Coelho🇧🇷 · José C. N. de Araujo🇧🇷

    Gravitational waves (GWs) emission due to magnetic deformation mechanism is applied for Soft Gamma Repeaters (SGRs) and Anomalous X-Ray Pulsars(AXPs), described as fast-spinning and magnetized white dwarfs (WDs). The emission is caused by the asymmetry around the rotation axis of the star generated by its own intense magnetic field. Thus, for the first time in the literature, it is estimated the GWs counterpart for SGRs/AXPs described as WD pulsars. We find that some SGRs/AXPs can be observed by the space detectors BBO and DECIGO. In particular, 1E 1547.0-5408 and SGR 1806-20 could be detected in 1 year of observation, whereas SGR 1900+14, CXOU J171405.7-381031, Swift J1834.9-0846 and SGR 1627-41 could be observed with a 5-year observation time. We also found that SGRs/AXPs as highly magnetized neutron stars are far below the sensitivity curves of BBO and DECIGO. This result indicates that a possible detection of continuous GWs originated from these objects would corroborate the WD pulsar model.

    ↳ astro-ph.SRastro-ph.HEhep-phMNRAS(2020)·9 citations
25. 25*

    Signals of Axion Like Dark Matter in Time Dependent Polarization of Light

    So Chigusa🇯🇵 · Takeo Moroi🇯🇵 · Kazunori Nakayama🇯🇵

    We consider the search for axion-like particles (ALPs) by using time series data of the polarization angle of the light. If the condensation of an ALP plays the role of dark matter, the polarization plane of the light oscillates as a function of time and we may be able to detect the signal of the ALP by continuously observing the polarization. In particular, we discuss that the analysis of the Fourier-transformed data of the time-dependent polarization angle is powerful to find the signal of the ALP dark matter. We pay particular attention to the light coming from astrophysical sources such as protoplanetary disks, supernova remnants, the foreground emission of the cosmic microwave background, and so on. We show that, for the ALP mass of $\sim 10^{-22}$--$10^{-19}\mathrm{eV}$, ALP searches in the Fourier space may reach the parameter region which is unexplored by other searches yet.

    ↳ astro-ph.COhep-phPLB(2020)·21 citations
26. 26*

    Lorentz invariance violations in the interplay of quantum gravity with matter

    Astrid Eichhorn🇩🇰 · Alessia Platania🇩🇪 · Marc Schiffer🇩🇪

    We explore the interplay of matter with quantum gravity with a preferred frame to highlight that the matter sector cannot be protected from the symmetry-breaking effects in the gravitational sector. Focusing on Abelian gauge fields, we show that quantum gravitational radiative corrections induce Lorentz-invariance-violating couplings for the Abelian gauge field. In particular, we discuss how such a mechanism could result in the possibility to translate observational constraints on Lorentz violation in the matter sector into strong constraints on the Lorentz-violating gravitational couplings.

    ↳ hep-thgr-qchep-phPRD(2020)·57 citations
27. 27*

    3D Yang-Mills confining properties from a non-Abelian ensemble perspective

    D. R. Junior🇧🇷 · L. E. Oxman🇧🇷 · G. M. Simões🇧🇷

    In this work, we propose a $3D$ ensemble measure for center-vortex worldlines and chains equipped with non-Abelian degrees of freedom. We derive an effective field description for the center-element average where the vortices get represented by $N$ flavors of effective Higgs fields transforming in the fundamental representation. This field content is required to accommodate fusion rules where $N$ vortices can be created out of the vacuum. The inclusion of the chain sector, formed by center-vortex worldlines attached to pointlike defects, leads to a discrete set of $Z(N)$ vacua. This type of SSB pattern supports the formation of a stable domain wall between quarks, thus accommodating not only a linear potential but also the Lüscher term. Moreover, after a detailed analysis of the associated field equations, the asymptotic string tension turns out to scale with the quadratic Casimir of the antisymmetric quark representation. These behaviors reproduce those derived from Monte Carlo simulations in $SU(N)$ $3D$ Yang-Mills theory, which lacked understanding in the framework of confinement as due to percolating magnetic defects.

    ↳ hep-thhep-phJHEP(2020)·11 citations
28. 28*

    The full four-loop cusp anomalous dimension in $\mathcal{N}=4$ super Yang-Mills and QCD

    Johannes M. Henn🇩🇪 · Gregory P. Korchemsky🇫🇷 · Bernhard Mistlberger🇺🇸

    We present the complete formula for the cusp anomalous dimension at four loops in QCD and in maximally supersymmetric Yang-Mills. In the latter theory it is given by \begin{equation} {\Gamma}^{\rm}_{\rm cusp}\Big|_{\alpha_s^4} = -\left( \frac{\alpha_s N}{\pi}\right)^4 \left[ \frac{73 \pi^6}{20160} + \frac{ \zeta_{3}^2}{8} + \frac{1}{N^2} \left( \frac{31\pi^6}{5040} + \frac{9 \zeta_3^2}{4} \right) \right] \,.\nonumber \end{equation} Our approach is based on computing the correlation function of a rectangular light-like Wilson loop with a Lagrangian insertion, normalized by the expectation value of the Wilson loop. In maximally supersymmetric Yang-Mills theory, this ratio is a finite function of a cross-ratio and the coupling constant. We compute it to three loops, including the full colour dependence. Integrating over the position of the Lagrangian insertion gives the four-loop Wilson loop. We extract its leading divergence, which determines the four-loop cusp anomalous dimension. Finally, we employ a supersymmetric decomposition to derive the last missing ingredient in the corresponding QCD result.

    ↳ hep-thhep-phJHEP(2020)·284 citations
29. 29*

    Conundrum for the free energy of a holonomous gluonic plasma at cubic order

    Christiaan P. Korthals Altes🇫🇷 · Hiromichi Nishimura🇯🇵 · Robert D. Pisarski🇺🇸 · Vladimir V. Skokov🇺🇸

    We compute the term $\sim g^3$ in the free energy for a $SU(N)$ gauge theory with nonzero holonomy at nonzero temperature. If the holonomy is generated kinematically by the introduction of gauge invariant sources coupled to Polyakov loops, the contribution of charged (off-diagonal) gluons to the free energy at order $g^3$, ${\mathcal{F}}^{\left(3:c.g.\right)}$, is singular: ${\mathcal{F}}^{\left(3:c.g.\right)}\ne 0$ without holonomy, but ${\mathcal{F}}^{\left(3:c.g.\right)}=0$ when the holonomy is nonzero, even infinitesimally. We show that the absence of the charged gluon contribution is required by gauge invariance alone and is therefore a universal feature.

    ↳ hep-thhep-lathep-phnucl-thPLB(2020)·9 citations
30. 30*

    Response relation in Pb-Pb and p-Pb collisions at 5.02 TeV

    De-Xian Wei🇨🇳 · Li-Juan Zhou🇨🇳 · Xin-Fei Li🇨🇳

    We carry out simulations using a multi-phase transport (AMPT) model to describe the response relation between $v_2$ and ${\epsilon }_2$ in Pb-Pb and p-Pb collisions at $\sqrt{s_{NN}}=5.02$ TeV, respectively. To simulate such relation, two methods have been introduced in the calculation: one is the directed response (DR) method, which correlates the outgoing particles with the initial anisotropy directly, and the other one is the cumulants response (CR) method, which is constructed from a cumulants correlation between outgoing particles. Based on calculations of the DR and CR methods, the response relations as a function of the transverse momentum are both shown in Pb-Pb and p-Pb collisions. By comparing the DR and CR methods, we found that the linear response relations are almost identical in all the present collisions. Similar results of linear+cubic response relations are also shown in the higher multiplicity systems, and it has become a significant difference in the lower multiplicity systems, i.e., the peripheral Pb-Pb collisions and p-Pb collisions. Throughout the whole $p_T$-dependent simulations, the ${\kappa }_2$ in the linear response and in the linear+cubic response are almost identical, except for in the lower multiplicity systems by the DR method. If one implements a pseudorapidity gap by the CR calculation, the $p_T$-dependent and $\eta$-independent response relations are similarly shown in peripheral Pb-Pb systems and p-Pb systems, which may imply that a collective response exists in the most central p-Pb collisions. These collective behaviors are dominantly produced on the stage of the medium expansions.

    ↳ nucl-thhep-phPRC(2020)·5 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.