Tue·Jul 9, 2019Tuesday·July 9, 2019

1. 01*

   Solving the Bethe-Salpeter Equation in Minkowski Space for a Fermion-Scalar system

   J.H. Alvarenga Nogueira (ITA & Sapienza - Rome U. & INFN)🇧🇷 · D. Colasante (Tor Vergata - Rome Univ.)🇮🇹 · V. Gherardi (Sissa & INFN Trieste)🇮🇹 · T. Frederico (ITA)🇧🇷 · E. Pace (Tor Vergata-Rome Univ. & INFN)🇮🇹 · G. Salmè (INFN - Rome)🇮🇹

   The ladder Bethe-Salpeter Equation of a bound (1/2)+ system, composed by a fermion and a scalar boson, is solved in Minkowski space, for the first time. The formal tools are the same already successfully adopted for two-scalar and two-fermion systems, namely the Nakanishi integral representation of the Bethe-Salpeter amplitude and the light-front projection of the fulfilled equation. Numerical results are presented and discussed for two interaction kernels: i) a massive scalar exchange and ii) a massive vector exchange, illustrating both the correlation between binding energies and the interaction coupling constants, as well as the valence content of the interacting state, through the valence probabilities and the light-front momentum distributions. In the case of the scalar exchange, an interesting side effect, to be ascribed to the repulsion generated by the small components of the Dirac spinor, is pointed out, while for the vector exchange the manifestation of the helicity conservation opens new interesting questions to be addressed within a fully non-perturbative framework, as well as the onset of a scale-invariant regime.

   hep-phcond-mat.otherPRD(2019)·14 citations
2. 02*

   Effective Coupling Constant of Plasmons

   Margaret E. Carrington🇨🇦 · Stanislaw Mrowczynski🇵🇱

   We study an ultrarelativistic QED plasma in thermal equilibrium. Plasmons - photon collective excitations - are postulated to correspond not to poles of the retarded photon propagator but to poles of the propagator multiplied by the fine structure constant. This product is an invariant of the renormalization group that is independent of an arbitrarily chosen renormalization scale. In addition, our proposal is physically motivated since one needs to scatter a charged particle off a plasma system to probe its spectrum of collective excitations. We present a detailed calculation of the QED running coupling constant at finite temperature using the Keldysh-Schwinger representation of the real-time formalism. We discuss the issue of how to choose the renormalization scale and show that the temperature is a natural choice which prevents the breakdown of perturbation theory through the generation of potentially large logarithmic terms. Our method could be applied to anisotropic systems where the choice of the renormalization scale is less clear, and could have important consequences for the study of collective modes.

   hep-phhep-thnucl-thPRD(2019)·4 citations
3. 03*

   Cross sections for 2-to-3 meson-meson scattering

   Wan-Xia Li🇨🇳 · Xiao-Ming Xu🇨🇳 · H. J. Weber🇺🇸

   We study 2-to-3 meson-meson scattering based on the process that a gluon is created from a constituent quark or antiquark and subsequently the gluon creates a quark-antiquark pair. The transition potential for the process is derived in QCD. Eight Feynman diagrams at tree level are involved in the 2-to-3 meson-meson scattering. Starting from the $S$-matrix element, we derive the unpolarized cross section from the eight transition amplitudes corresponding to the eight Feynman diagrams. The transition amplitudes contain color, spin, and flavor matrix elements. The 2-to-3 meson-meson scattering includes $\pi \pi \to \pi K\bar{K}$, $\pi K\to \pi \pi K$, $\pi K\to KK\bar{K}$, $KK\to \pi KK$, and $K\bar{K}\to \pi K\bar{K}$. Cross sections for the reactions are calculated. The cross sections depend on temperature obviously, and the cross section for $\pi K\to \pi \pi K$ for total isospin $I=3/2$ at zero temperature is compared to experimental data. By comparison with inelastic 2-to-2 meson-meson scattering, we find that 2-to-3 meson-meson scattering may be as important as inelastic 2-to-2 meson-meson scattering.

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

   The decays $\tau \to [\omega (782),\varphi (1020)]K^{-}{\nu }_{\tau }$ in the extended NJL model

   M. K. Volkov🇷🇺 · A. A. Pivovarov🇷🇺 · K. Nurlan🇷🇺

   In the extended Nambu--Jona-Lasinio model, the decay widths of the processes $\tau \to [\omega (782),\varphi (1020)]K^{-}{\nu }_{\tau }$ were calculated. The intermediate channels with axial vector ($K_1(1270)$, $K_1(1400)$ and $K_1(1650)$), vector ($K^{\ast }(892)$ and $K^{\ast }(1410)$) and pseudoscalar ($K$ and $K(1460)$) mesons were considered. The results for these processes are in satisfactory agreement with the experimental data.

   hep-phEPJA(2019)·11 citations
5. 05*

   Potentialities of a low-energy detector based on ${}^4$He evaporation to observe atomic effects in coherent neutrino scattering and physics perspectives

   M. Cadeddu🇮🇹 · F. Dordei🇮🇹 · C. Giunti🇮🇹 · K. A. Kouzakov🇷🇺 · E. Picciau🇮🇹 · A. I. Studenikin🇷🇺

   We propose an experimental setup to observe coherent elastic neutrino-atom scattering (CE$\nu$AS) using electron antineutrinos from tritium decay and a liquid helium target. In this scattering process with the whole atom, that has not beeen observed so far, the electrons tend to screen the weak charge of the nucleus as seen by the electron antineutrino probe. The interference between the nucleus and the electron cloud produces a sharp dip in the recoil spectrum at atomic recoil energies of about 9 meV, reducing sizeably the number of expected events with respect to the coherent elastic neutrino-nucleus scattering case. We estimate that with a 60 g tritium source surrounded by 500 kg of liquid helium in a cylindrical tank, one could observe the existence of CE$\nu$AS processes at 3$\sigma$ in 5 years of data taking. Keeping the same amount of helium and the same data-taking period, we test the sensitivity to the Weinberg angle and a possible neutrino magnetic moment for three different scenarios: 60 g, 160 g, and 500 g of tritium. In the latter scenario, the Standard Model (SM) value of the Weinberg angle can be measured with a statistical uncertainty of ${\sin }^2{{\vartheta }_W^{\mathrm{SM}}}_{-0.016}^{+0.015}$. This would represent the lowest-energy measurement of ${\sin }^2{\vartheta }_W$, with the advantage of being not affected by the uncertainties on the neutron form factor of the nucleus as the current lowest-energy determination. Finally, we study the sensitivity of this apparatus to a possible electron neutrino magnetic moment and we find that using 60 g of tritium it is possible to set an upper limit of about $7\times 10^{-13}{\mu }_B$ at 90% C.L., that is more than one order of magnitude smaller than the current experimental limit.

   hep-phhep-exPRD(2019)·37 citations
6. 06*

   Multiplicity distribution in pseudo-rapidity windows and charge conservation

   N. Suzuki🇯🇵 · M. Biyajima🇯🇵 · T. Mizoguchi🇯🇵

   Charged multiplicity distribution in a pseudo-rapidity window is formulated under the assumption that the charge conservation is satisfied in the full phase space. At first, we analyze measured charged particle multiplicity distributions in pseudo-rapidity windows in LHC by CMS and ALICE collaborations with the two probability distributions. One is the convolution of negative binomial and Poisson distributions, and the other is the Glauber-Lachs formula. Each distribution is considered as an analogy of the quantum optics. Next, we analyze the data with the double GL formulae for $|\eta |<2.4$ at 7 TeV by the CMS collaboration and for $|\eta |<1.5$ at 8 TeV by the ALICE collaboration to describe the global structure of measured distributions.

   hep-phJ.Phys.G(2021)·1 citation
7. 07*

   TMDs and Monte Carlo Event Generators

   F. Hautmann🇧🇪

   We discuss prospects for Monte Carlo event generators incorporating the dynamics of transverse momentum dependent (TMD) parton distribution functions. We illustrate TMD evolution in the parton branching formalism, and present Monte Carlo applications of the method.

   hep-phPoS(2019)·5 citations
8. 08*

   Evidence against naive truncations of the OPE from $e^{+}{e}^{-}\to$ hadrons below charm

   Diogo Boito🇧🇷 · Maarten Golterman🇺🇸 · Kim Maltman🇨🇦 · Santiago Peris🇪🇸

   The operator product expansion (OPE), truncated in dimension, is employed in many contexts. An example is the extraction of the strong coupling, ${\alpha }_s$, from hadronic $\tau$-decay data, using a variety of analysis methods based on finite-energy sum rules. Here, we reconsider a long-used method, which parametrizes non-perturbative contributions to the $I=1$ vector and axial vacuum polarizations with the OPE, setting several higher-dimension coefficients to zero in order to implement the method in practice. The assumption that doing this has a negligible effect on the value of ${\alpha }_s$ is tantamount to the assumption that the low-dimension part of the OPE converges rapidly with increasing dimension near the $\tau$ mass. Were this assumption valid, it would certainly have to be valid at energies above the $\tau$ mass as well. It follows that the method can be tested using data obtained from $e^{+}{e}^{-}\to \text{mbox}hadrons$, as they are not limited by the kinematic constraints of $\tau$ decays. We carry out such an investigation using a recent high-precision compilation for the $R$-ratio, arguing that it provides insights into the validity of the strategy, even if it probes a different, though related channel. We find that $e^{+}{e}^{-}$-based tests call into question the implied assumption of rapid convergence of the low-dimension part of the OPE around the $\tau$ mass, and thus underscore the need to restrict finite-energy sum-rule analyses to observables which receive only contributions from lower-order terms in the OPE.

   hep-phhep-exhep-latPRD(2019)·19 citations
9. 09*

   Theory of elastic neutrino-electron scattering

   Oleksandr Tomalak🇩🇪 · Richard J Hill🇺🇸

   Theoretical predictions for elastic neutrino-electron scattering have no hadronic or nuclear uncertainties at leading order making this process an important tool for normalizing neutrino flux. However, the process is subject to large radiative corrections that differ according to experimental conditions. In this paper, we collect new and existing results for total and differential cross sections accompanied by radiation of one photon, $\nu e\to \nu e(\gamma )$. We perform calculations within the Fermi effective theory and provide analytic expressions for the electron energy spectrum and for the total electromagnetic energy spectrum as well as for double- and triple-differential cross sections with respect to electron energy, electron angle, photon energy, and photon angle. We discuss illustrative applications to accelerator-based neutrino experiments and provide the most precise up-to-date values of neutrino-electron scattering cross sections. We present an analysis of theoretical error, which is dominated by the $\sim 0.2-0.4\%$ uncertainty of the hadronic correction. We also discuss how searches for new physics can be affected by radiative corrections.

   hep-phhep-exnucl-exnucl-thPRD(2020)·78 citations
10. 10*

    Baryon-Dark Matter Coincidence in Mirrored Unification

    Masahiro Ibe🇯🇵 · Ayuki Kamada🇰🇷 · Shin Kobayashi🇯🇵 · Takumi Kuwahara🇰🇷 · Wakutaka Nakano🇯🇵

    About 80\% of the mass of the present Universe is made up of the unknown (dark matter), while the rest is made up of ordinary matter. It is a very intriguing question why the {\it mass} densities of dark matter and ordinary matter (mainly baryons) are close to each other. It may be hinting the identity of dark matter and furthermore structure of a dark sector. A mirrored world provides a natural explanation to this puzzle. On the other hand, if mirror-symmetry breaking scale is low, it tends to cause cosmological problems. In this letter, we propose a mirrored unification framework, which breaks mirror-symmetry at the grand unified scale, but still addresses the puzzle. The dark matter mass is strongly related with the dynamical scale of QCD, which explains the closeness of the dark matter and baryon masses. Intermediate-energy portal interactions share the generated asymmetry between the visible and dark sectors. Furthermore, our framework is safe from cosmological issues by providing low-energy portal interactions to release the superfluous entropy of the dark sector into the visible sector.

    hep-phPRD(2019)·49 citations
11. 11*

    Decays of $P_c$ into $J/\psi N$ and ${\eta }_{c}N$ with heavy quark spin symmetry

    Shuntaro Sakai🇨🇳 · Hao-Jie Jing🇨🇳 · Feng-Kun Guo🇨🇳

    We investigate the consequences of heavy quark spin symmetry (HQSS) on hidden-charm pentaquark $P_c$ states. As has been proposed before, assuming the $P_c(4440)$ and the $P_c(4457)$ as $S$-wave ${\bar{D}}^{\ast }{\Sigma }_c$ molecules, seven hadronic molecular states composed of $\bar{D}{\Sigma }_c$, $\bar{D}{\Sigma }_c^{\ast }$, ${\bar{D}}^{\ast }{\Sigma }_c$, and ${\bar{D}}^{\ast }{\Sigma }_c^{\ast }$ can be obtained, with the $\bar{D}{\Sigma }_c$ molecule corresponding to the $P_c(4312)$. These seven states can decay into $J/\psi N$ and ${\eta }_{c}N$, and we use HQSS to predict ratios of partial widths of the $S$-wave decays. For the decays into $J/\psi N$, it is found that among all six $P_c$ molecules with spin $1/2$ or $3/2$, at least four states decay much more easily into the $J/\psi N$ than the $P_c(4312)$, and two of them couple dominantly to the ${\bar{D}}^{\ast }{\Sigma }_c^{\ast }$. While no significant peak around the ${\bar{D}}^{\ast }{\Sigma }_c^{\ast }$ threshold is found in the $J/\psi p$ distribution, these higher $P_c$ states either are produced with lower rates or some special production mechanism for the observed $P_c$ states might play an important role, such as an intricate interplay between the production of pentaquarks and triangle singularities.

    hep-phPRD(2019)·86 citations
12. 12*

    Mapping collinear in-medium parton splittings

    Fabio Dominguez🇪🇸 · Jose Guilherme Milhano🇵🇹 · Carlos A. Salgado🇪🇸 · Konrad Tywoniuk🇳🇴 · Victor Vila🇪🇸

    We map the spectrum of $1\to 2$ parton splittings inside a medium characterized by a transport coefficient $\hat{q}$ onto the kinematical Lund plane, taking into account the finite formation time of the process. We discuss the distinct regimes arising in this map for in-medium splittings, pointing out the close correspondence to a semi-classical description in the limit of hard, collinear radiation with short formation times. Although we disregard any modifications of the original parton kinematics in course of the propagation through the medium, subtle modifications to the radiation pattern compared to the vacuum baseline can be traced back to the physics of color decoherence and accumulated interactions in the medium. We provide theoretical support to vacuum-like emissions inside the medium by delimiting the regions of phase space where it is dominant, identifying also the relevant time-scales involved. The observed modifications are shown to be quite general for any dipole created in the medium.

    hep-phnucl-thEPJC(2020)·57 citations
13. 13*

    Effect of non-eikonal corrections on azimuthal asymmetries in the Color Glass Condensate

    Pedro Agostini🇪🇸 · Tolga Altinoluk🇵🇱 · Néstor Armesto🇪🇸

    We analyse the azimuthal structure of two gluon correlations in the Color Glass Condensate including those effects that result from relaxing the shockwave approximation for the target. Working in the Glasma graph approach suitable for collisions between dilute systems, we compute numerically the azimuthal distributions and show that both even and odd harmonics appear. We study their dependence on model parameters, energy of the collision, pseudorapidity and transverse momentum of the produced particles, and length of the target. While the contribution from non-eikonal corrections vanishes with increasing collision energy and becomes negligible at the energies of the Large Hadron Collider, it is found to be sizeable up to top energies at the Relativistic Heavy Ion Collider.

    hep-phnucl-thEPJC(2019)·44 citations
14. 14*

    Searching for periodic signals in kinematic distributions using continuous wavelet transforms

    Hugues Beauchesne🇮🇱 · Yevgeny Kats🇮🇱

    Many models of physics beyond the Standard Model include towers of particles whose masses follow an approximately periodic pattern with little spacing between them. These resonances might be too weak to detect individually, but could be discovered as a group by looking for periodic signals in kinematic distributions. The continuous wavelet transform, which indicates how much a given frequency is present in a signal at a given time, is an ideal tool for this. In this paper, we present a series of methods through which continuous wavelet transforms can be used to discover periodic signals in kinematic distributions. Some of these methods are based on a simple test statistic, while others make use of machine learning techniques. Some of the methods are meant to be used with a particular model in mind, while others are model-independent. We find that continuous wavelet transforms can give bounds comparable to current searches and, in some cases, be sensitive to signals that would go undetected by standard experimental strategies.

    hep-phhep-exEPJC(2020)·9 citations
15. 15*

    How to GAN LHC Events

    Anja Butter🇩🇪 · Tilman Plehn🇩🇪 · Ramon Winterhalder🇩🇪

    Event generation for the LHC can be supplemented by generative adversarial networks, which generate physical events and avoid highly inefficient event unweighting. For top pair production we show how such a network describes intermediate on-shell particles, phase space boundaries, and tails of distributions. In particular, we introduce the maximum mean discrepancy to resolve sharp local features. It can be extended in a straightforward manner to include for instance off-shell contributions, higher orders, or approximate detector effects.

    hep-phSciPost Phys.(2019)·191 citations
16. 16*

    Axion-like Relics: New Constraints from Old Comagnetometer Data

    Itay M. Bloch🇮🇱 · Yonit Hochberg🇮🇱 · Eric Kuflik🇮🇱 · Tomer Volansky🇮🇱

    The noble-alkali comagnetometer, developed in recent years, has been shown to be a very accurate measuring device of anomalous magnetic-like fields. An ultra-light relic axion-like particle can source an anomalous field that permeates space, allowing for its detection by comagnetometers. Here we derive new constraints on relic axion-like particles interaction with neutrons and electrons from old comagnetometer data. We show that the decade-old experimental data place the most stringent terrestrial constraints to date on ultra-light axion-like particles coupled to neutrons. The constraints are comparable to those from stellar cooling, providing a complementary probe. Future planned improvements of comagnetometer measurements through altered geometry, constituent content and data analysis techniques could enhance the sensitivity to axion-like relics coupled to nucleons or electrons by many orders of magnitude.

    hep-phhep-exJHEP(2020)·100 citations
17. 17*

    Linearly polarized gluons at next-to-next-to leading order and the Higgs transverse momentum distribution

    Daniel Gutierrez-Reyes🇪🇸 · Sergio Leal-Gomez🇪🇸 · Ignazio Scimemi🇪🇸 · Alexey Vladimirov🇩🇪

    We calculate the small-b (or large-qT) matching of transverse momentum dependent (TMD) distribution for linearly polarized gluons to the integrated gluon distributions at the next-to-next-to-leading order (NNLO). This is the last missing part for the complete NNLO prediction of the Higgs spectrum within TMD factorization. We discuss the numerical impact of the correction so derived to the qT-differential cross-section for Higgs boson production and to the positivity bound for linearly polarized gluon transverse momentum distribution.

    hep-phhep-exhep-latnucl-ex+1JHEP(2019)·79 citations
18. 18*

    Bounds on Cosmic Ray-Boosted Dark Matter in Simplified Models and its Corresponding Neutrino-Floor

    James B. Dent🇺🇸 · Bhaskar Dutta🇺🇸 · Jayden L. Newstead🇺🇸 · Ian M. Shoemaker🇺🇸

    We study direct detection bounds on cosmic ray-upscattered dark matter in simplified models including light mediators. We find that the energy dependence in the scattering cross section is significant, and produces stronger bounds than previously found (which assumed constant cross sections) by many orders of magnitude at low DM mass. Finally, we compute the "neutrino-floor" that will limit future direct detection searches for cosmic ray-upscattered dark matter. While we focus on vector interactions for illustration, we emphasize that the energy dependence is critical in determining accurate bounds on any particle physics model of Dark Matter-CR interactions from experimental data on this scenario.

    hep-phastro-ph.COPRD(2020)·115 citations
19. 19*

    Charged pion condensation and duality in dense and hot chirally and isospin asymmetric quark matter in the framework of NJL${}_2$ model

    T. G. Khunjua🇷🇺 · K. G. Klimenko🇷🇺 · R. N. Zhokhov🇷🇺

    In this paper we investigate in the large-$N_c$ limit ($N_c$ is the number of colored quarks) the phase structure of a massless (1+1)-dimensional quark model with four-quark interaction and in the presence of baryon (${\mu }_B$), isospin (${\mu }_I$) and chiral isospin (${\mu }_{I5}$) chemical potentials as well as at nonzero temperature. It is established that chiral isospin chemical potential leads to the generation of charged pion condensation (PC) in dense (nonzero baryon density) and chiral asymmetric quark matter for a wide range of isospin densities. It is shown that there exists a duality correspondence between the chiral symmetry breaking and the charged PC phenomena at any values of temperature even for very hot quark gluon plasma. Moreover, it is shown that charged PC phase with nonzero baryon density can be induced in the model at comparatively high temperatures. This opens up new possible physical systems, where it can be of importance, such as heavy ion collisions, just born neutron stars (proto-neutron stars), supernovas as well as neutron star mergers.

    hep-phhep-thnucl-thPRD(2019)·36 citations
20. 20*

    Lepton mixing patterns from $PS{L}_2(7)$ with a generalised CP symmetry

    Shu-Jun Rong🇨🇳

    Lepton mixing patterns from the modular group $PS{L}_2(7)$ with generalised CP symmetries are studied. The residual symmetries in both charged leptons and neutrinos sector are $Z_2\times CP$. Seven types of mixing patterns at the $3\sigma$ level of the new global fit data are obtained. Among these patterns, three types of patterns can give the Dirac CP phase which is in the $1\sigma$ range of the global fit data. The effective mass of neutrinoless double-beta decay for these patterns are also examined.

    hep-phAdv.High Energy Phys.(2020)·4 citations
21. 21*

    Analytical model for gravitational-wave echoes from spinning remnants

    Elisa Maggio🇮🇹 · Adriano Testa🇺🇸 · Swetha Bhagwat🇮🇹 · Paolo Pani🇮🇹

    Gravitational-wave echoes in the post-merger signal of a binary coalescence are predicted in various scenarios, including near-horizon quantum structures, exotic states of matter in ultracompact stars, and certain deviations from general relativity. The amplitude and frequency of each echo is modulated by the photon-sphere barrier of the remnant, which acts as a spin- and frequency-dependent high-pass filter, decreasing the frequency content of each subsequent echo. Furthermore, a major fraction of the energy of the echo signal is contained in low-frequency resonances corresponding to the quasi-normal modes of the remnant. Motivated by these features, in this work we provide an analytical gravitational-wave template in the low-frequency approximation describing the post-merger ringdown and the echo signal of a spinning ultracompact object. Besides the standard ringdown parameters, the template is parametrized in terms of only two physical quantities: the reflectivity coefficient and the compactness of the remnant. We discuss novel effects related to the spin and to the complex reflectivity, such as a more involved modulation of subsequent echoes, the mixing of two polarizations, and the ergoregion instability in case of perfectly-reflecting spinning remnants. Finally, we compute the errors in the estimation of the template parameters with current and future gravitational-wave detectors using a Fisher matrix framework. Our analysis suggests that models with almost perfect reflectivity can be excluded/detected with current instruments, whereas probing values of the reflectivity smaller than $80\%$ at $3\sigma$ confidence level requires future detectors (Einstein Telescope, Cosmic Explorer, LISA). The template developed in this work can be easily implemented to perform a matched-filter based search for echoes and to constrain models of exotic compact objects.

    ↳ gr-qcastro-ph.HEhep-phhep-thPRD(2019)·109 citations
22. 22*

    Is gravity getting weaker at low z? Observational evidence and theoretical implications

    Lavrentios Kazantzidis🇬🇷 · Leandros Perivolaropoulos🇬🇷

    Dynamical observational probes of the growth of density perturbations indicate that gravity may be getting weaker at low redshifts $z$. This evidence is at about $2-3\sigma$ level and comes mainly from weak lensing data that measure the parameter $S_8={\sigma }_8\sqrt{{\Omega }_{0m}/0.3}$ and redshift space distortion data that measure the growth rate times the amplitude of the linear power spectrum parameter $f{\sigma }_8(z)$. The measured $f{\sigma }_8$ appears to be lower than the prediction of General Relativity (GR) in the context of the standard $\Lambda$CDM model as defined by the Planck best fit parameter values. This is the well known $f{\sigma }_8$ tension of $\Lambda$CDM, which constitutes one of the two main large scale challenges of the model along with the $H_0$ tension. We review the observational evidence that leads to the $f{\sigma }_8$ tension and discuss some theoretical implications. If this tension is not a systematic effect it may be an early hint of modified gravity with an evolving effective Newton's constant $G_{eff}$ and gravitational slip parameter $\eta$. We discuss such best fit parametrizations of $G_{eff}(z)$ and point out that they can not be reproduced by simple scalar-tensor and $f(R)$ modified gravity theories because these theories generically predict stronger gravity than General Relativity (GR) at low $z$ in the context of a $\Lambda$CDM background $H(z)$. Finally, we show weak evidence for an evolving reduced absolute magnitude of the SnIa of the Pantheon dataset at low redshifts ($z<0.1$) which may also be explained by a reduced strength of gravity and may help resolve the $H_0$ tension.

    ↳ astro-ph.COgr-qchep-phhep-th49 citations
23. 23*

    Cosmological parameter estimation with future gravitational wave standard siren observation from the Einstein Telescope

    Jing-Fei Zhang🇨🇳 · Ming Zhang🇨🇳 · Shang-Jie Jin🇨🇳 · Jing-Zhao Qi🇨🇳 · Xin Zhang🇨🇳

    In this work, we use the simulated gravitational wave (GW) standard siren data from the future observation of the Einstein Telescope (ET) to constrain various dark energy cosmological models, including the $\Lambda$CDM, $w$CDM, CPL, $\alpha$DE, GCG, and NGCG models. We also use the current mainstream cosmological electromagnetic observations, i.e., the cosmic microwave background anisotropies data, the baryon acoustic oscillations data, and the type Ia supernovae data, to constrain these models. We find that the GW standard siren data could tremendously improve the constraints on the cosmological parameters for all these dark energy models. For all the cases, the GW standard siren data can be used to break the parameter degeneracies generated by the current cosmological electromagnetic observational data. Therefore, it is expected that the future GW standard siren observation from the ET would play a crucial role in the cosmological parameter estimation in the future. The conclusion of this work is quite solid because it is based on the analysis for various dark energy models.

    ↳ astro-ph.COgr-qchep-phJCAP(2019)·83 citations
24. 24*

    System size scan of D meson $R_{\text{AA}}$ and $v_n$ using PbPb, XeXe, ArAr, and OO collisions at LHC

    Roland Katz🇫🇷 · Caio A. G. Prado🇨🇳 · Jacquelyn Noronha-Hostler🇺🇸 · Alexandre A. P. Suaide🇧🇷

    Experimental measurements indicate no suppression (e.g. $R_{\text{pPb}}\sim 1$) but a surprisingly large D meson $v_2$ was measured in pPb collisions. In order to understand these results we use Trento+v-USPhydro+DAB-MOD to make predictions and propose a system size scan at the LHC involving ${}^{208}$PbPb, ${}^{129}$XeXe, ${}^{40}$ArAr, and ${}^{16}$OO collisions. We find that the nuclear modification factor approaches unity as the system size is decreased, but nonetheless, in the 0-10% most central collisions $v_2\{2\}$ is roughly equivalent regardless of system size. These results arise from a rather non-trivial interplay between the shrinking path length and the enhancement of eccentricities in small systems at high multiplicity. Finally, we also find a surprising sensitivity of D mesons $v_2\{2\}$ in 0-10% at $p_T=2-10$ GeV to the slight deformation of ${}^{129}$Xe recently found at LHC.

    ↳ nucl-thhep-exhep-phPRC(2020)·47 citations
25. 25*

    Viscosity in cosmic fluids

    Pravin Kumar Natwariya🇮🇳 · Jitesh R Bhatt🇮🇳 · Arun Kumar Pandey🇮🇳

    The effective theory of large-scale structure formation based on $\Lambda$CDM paradigm predicts finite dissipative effects in the resulting fluid equations. In this work, we study how viscous effect that could arise if one includes self-interaction among the dark-matter particles combines with the effective theory. It is shown that these two possible sources of dissipation can operate together in a cosmic fluid and the interplay between them can play an important role in determining dynamics of the cosmic fluid. In particular, we demonstrate that the viscosity coefficient due to self-interaction is added inversely with the viscosity calculated using effective theory of $\Lambda$CDM model. Thus the larger viscosity has less significant contribution in the effective viscosity. Using the known bounds on $\sigma /m$ for self-interacting dark-matter, where $\sigma$ and $m$ are the cross-section and mass of the dark-matter particles respectively, we discuss role of the effective viscosity in various cosmological scenarios.

    ↳ astro-ph.COastro-ph.GAhep-phphysics.flu-dynEPJC(2020)·16 citations
26. 26*

    Electroweak Physics with Polarized Electron Beams in a SuperKEKB Upgrade

    J.Michael Roney🇨🇦

    Consideration is being given to upgrading the SuperKEKB e${}^{+}$e${}^{-}$ collider with polarized electron beams, which would open a new program of precision electroweak physics at a centre-of-mass energy of 10.58GeV, the mass of the ${\rm Y}(4S)$. These measurements include ${\sin }^2{\theta }_W$ obtained via left-right asymmetry measurements of e${}^{+}$e${}^{-}$ transitions to pairs of electrons, muons, taus, charm and b-quarks. The precision obtainable at SuperKEKB will match that of the LEP/SLC world average and will thereby probe the neutral current couplings with unprecedented precision at a new energy scale sensitive to the running of the couplings. At SuperKEKB the measurements of the individual neutral current vector coupling constants to b-quarks and c-quarks and muons in particular will be substantially more precise than current world averages and the current 3$\sigma$ discrepancy between the SLC A${}_{LR}$ measurements and LEP A${}_{FB}^b$ measurements of ${\sin }^2{\theta }_W^{eff}$ will be addressed. This paper will include a discussion of the necessary upgrades to SuperKEKB. This program opens an exciting new window in searches for physics beyond the Standard Model.

    ↳ hep-exhep-phPoS(2019)·10 citations
27. 27*

    Performance and science reach of POEMMA for ultrahigh-energy particles

    Luis A. Anchordoqui🇺🇸 · Douglas R. Bergman🇺🇸 · Mario E. Bertaina🇮🇹 · Francesco Fenu🇮🇹 · John F. Krizmanic🇺🇸 · Alessandro Liberatore🇮🇹 · Angela V. Olinto🇺🇸 · Mary Hall Reno🇺🇸 · Fred Sarazin🇺🇸 · Kenji Shinozaki🇮🇹 · Jorge F. Soriano🇺🇸 · Ralf Ulrich🇩🇪 and 3 other authors

    The Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) is a potential NASA Astrophysics Probe-class mission designed to observe ultra-high energy cosmic rays (UHECRs) and cosmic neutrinos from space. POEMMA will monitor colossal volumes of the Earth's atmosphere to detect extensive air showers (EASs) produced by extremely energetic cosmic messengers: UHECRs above 20 EeV over the full sky and cosmic neutrinos above 20 PeV. We focus most of this study on the impact of POEMMA for UHECR science by simulating the detector response and mission performance for EAS from UHECRs. We show that POEMMA will provide a significant increase in the statistics of observed UHECRs at the highest energies over the entire sky. POEMMA will be the first UHECR fluorescence detector deployed in space that will provide high-quality stereoscopic observations of the longitudinal development of air showers. Therefore, it will be able to provide event-by-event estimates of the calorimetric energy and nuclear mass of UHECRs. The particle physics in the interactions limits the interpretation of the shower maximum on an event by event basis. In contrast, the calorimetric energy measurement is significantly less sensitive to the different possible final states in the early interactions. We study the prospects to discover the origin and nature of UHECRs using expectations for measurements of the energy spectrum, the distribution of arrival direction, and the atmospheric column depth at which the EAS longitudinal development reaches maximum. We also explore supplementary science capabilities of POEMMA through its sensitivity to particle interactions at extreme energies and its ability to detect ultra-high energy neutrinos and photons produced by top-down models including cosmic strings and super-heavy dark matter particle decay in the halo of the Milky Way.

    ↳ astro-ph.HEhep-phPRD(2020)·43 citations
28. 28*

    Rolling with quantum fields

    Mainak Mukhopadhyay🇺🇸 · Tanmay Vachaspati🇺🇸

    We study the dynamics of a classical scalar field that rolls down a linear potential as it interacts bi-quadratically with a quantum field. We explicitly solve the dynamical problem by using the classical-quantum correspondence (CQC). Rolling solutions on the effective potential are shown to compare very poorly with the full solution. Spatially homogeneous initial conditions maintain their homogeneity and small inhomogeneities in the initial conditions do not grow.

    ↳ hep-thcond-mat.othergr-qchep-ph+1PRD(2019)·17 citations
29. 29*

    Phase transitions in neutron stars and their links to gravitational waves

    Milva G. Orsaria🇦🇷 · Germán Malfatti🇦🇷 · Mauro Mariani🇦🇷 · Ignacio F. Ranea-Sandoval🇦🇷 · Federico García🇫🇷 · William M. Spinella🇺🇸 · Gustavo A. Contrera🇦🇷 · Germán Lugones🇧🇷 · Fridolin Weber🇺🇸

    The recent direct observation of gravitational wave event $GW170817$ and its $GRB170817A$ signal has opened up a new window to study neutron stars and heralds a new era of Astronomy referred to as the Multimessenger Astronomy. Both gravitational and electromagnetic waves from a single astrophysical source have been detected for the first time. This combined detection offers an unprecedented opportunity to place constraints on the neutron star matter equation of state. The existence of a possible hadron-quark phase transition in the central regions of neutron stars is associated with the appearance of g-modes, which are extremely important as they could signal the presence of a pure quark matter core in the centers of neutron stars. Observations of g-modes with frequencies between 1 kHz and 1.5 kHz could be interpreted as evidence of a sharp hadron-quark phase transition in the cores of neutron stars. In this article, we shall review the description of the dense matter composing neutron stars, the determination of the equation of state of such matter, and the constraints imposed by astrophysical observations of these fascinating compact objects.

    ↳ astro-ph.HEhep-phnucl-thJ.Phys.G(2019)·75 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.