Nuclear Theory·nucl-th

Monday·July 30, 2018

7 papers—2 primary·5 cross-listed

03
Proper effective temperature of nonequilibrium steady state
Hironori Hoshino🇯🇵 · Shin Nakamura🇯🇵
We define a proper effective temperature for relativistic nonequilibrium steady states (NESSs). A conventional effective temperature of NESSs is defined from the ratio of the fluctuation to the dissipation. However, NESSs have relative velocities to the heat bath in general, and hence the conventional effective temperature can be frame dependent in relativistic systems. The proper effective temperature is introduced as a frame-independent (Lorentz invariant) quantity that characterizes NESSs. We find that the proper effective temperature of NESSs is higher than the proper temperature of the heat bath in a wide range of holographic models even when the conventional effective temperature is lower than the temperature of the heat bath.
↳ hep-thcond-mat.stat-mechgr-qchep-ph+1PTEP(2020)·5 citations
04
Forward Elastic Scattering and Pomeron Models
M. Broilo🇧🇷 · E.G.S. Luna🇧🇷 · M.J. Menon🇧🇷
Recent data from LHC13 by the TOTEM Collaboration have indicated an unexpected decrease in the value of the $ρ$ parameter and a $σ_{t o t}$ value in agreement with the trend of previous measurements at 7 and 8 TeV. These data at 13 TeV are not simultaneously described by the predictions from Pomeron models selected by the COMPETE Collaboration, but show agreement with the maximal Odderon dominance, as recently demonstrated by Martynov and Nicolescu. Here we present a detailed analysis on the applicability of Pomeron dominance by means of a general class of forward scattering amplitude, consisting of even-under-crossing leading contributions associated with single, double and triple poles in the complex angular momentum plane. We carry out fits to $pp$ and $p ˉ p$ data in the interval 5 GeV - 13 TeV. The data set comprises all the accelerator data below 7 TeV and we consider two independent ensembles by adding either only the TOTEM data or TOTEM and ATLAS data at the LHC energy region. In the data reductions to each ensemble the uncertainty regions are evaluated with both one and two standard deviation ( $\sim$ 68 \% and $\sim$ 95 \% CL, respectively). Besides the general analytic model, we investigate four particular cases of interest, three of them typical of outstanding models in the literature. We conclude that, within the experimental and theoretical uncertainties and both ensembles, the general model and three particular cases are not able to describe the $σ_{t o t}$ and $ρ$ data at 13 TeV simultaneously. However, if the discrepancies between the TOTEM and ATLAS data are not resolved, one Pomeron model, associated with double and triple poles and with only 7 free parameters, seems not to be excluded by the complete set of experimental information presently available.
↳ hep-phhep-exnucl-thPRD(2018)·23 citations
05
The Quark-Gluon Vertex and the QCD Infrared Dynamics
O. Oliveira🇵🇹 · W. de Paula🇧🇷 · T. Frederico🇧🇷 · J. P. B. C de Melo🇧🇷
The Dyson-Schwinger quark equation is solved for the quark-gluon vertex using the most recent lattice data available in the Landau gauge for the quark, gluon and ghost propagators, the full set of longitudinal tensor structures in the Ball-Chiu vertex, taking into account a recently derived normalisation for a quark-ghost kernel form factors and the gluon contribution for the tree level quark-gluon vertex identified on a recent study of the lattice soft gluon limit. A solution for the inverse problem is computed after the Tikhonov linear regularisation of the integral equation, that implies solving a modified Dyson-Schwinger equation. We get longitudinal form factors that are strongly enhanced at the infrared region, deviate significantly from the tree level results for quark and gluon momentum below 2 GeV and at higher momentum approach their perturbative values. The computed quark-gluon vertex favours kinematical configurations where the quark momentum $p$ and the gluon momentum $q$ are small and parallel. Further, the quark-gluon vertex is dominated by the form factors associated to the tree level vertex $γ_{μ}$ and to the operator $2 p_{μ} + q_{μ}$ . The higher rank tensor structures provide small contributions to the vertex.
↳ hep-phhep-lathep-thnucl-thEPJC(2019)·35 citations
06
Cross Sections for Inelastic 2-to-2 Meson-Meson Scattering in Hadronic Matter
Ting-Ting Wang🇨🇳 · Xiao-Ming Xu🇨🇳
With quark-antiquark annihilation and creation in the first Born approximation, we study the reactions: $K K ˉ \to K K ˉ^{*}, K K ˉ \to K^{*} K ˉ, π K \to π K^{*}, π K \to ρ K, π π \to K K ˉ^{*}, π π \to K^{*} K ˉ, π π \to K^{*} K ˉ^{*}, π ρ \to K K ˉ, π ρ \to K^{*} K ˉ^{*}, ρρ \to K^{*} K ˉ^{*}, K K ˉ^{*} \to ρρ$ , and $K^{*} K ˉ \to ρρ$ . Unpolarized cross sections for the reactions are obtained from transition amplitudes that are composed of mesonic quark-antiquark relative-motion wave functions and the transition potential for quark-antiquark annihilation and creation. From a quark-antiquark potential that is equivalent to the transition potential, we prove that the total spin of the two final mesons may not equal the total spin of the two initial mesons. Based on flavor matrix elements, cross sections for some isospin channels of reactions can be obtained from the other isospin channels of reactions. Remarkable temperature dependence of the cross sections is found.
↳ hep-phnucl-thCPC(2019)·3 citations
07
$γ$ -vibration in $^{198}$ Hg
S. Chakraborty🇮🇳 · H. P. Sharma🇮🇳 · S. S. Tiwary🇮🇳 · C. Majumder🇮🇳 · P. Banerjee🇮🇳 · S. Ganguly🇮🇳 · S. Muralithar🇮🇳 · R. P. Singh🇮🇳 · G. H. Bhat🇮🇳 · J. A. Sheikh🇮🇳 · R. Palit🇮🇳
Low lying states of $^{198}$ Hg have been investigated via $^{197}$ Au( $^{7}$ Li, $α$ 2n $γ$ ) $^{198}$ Hg reaction at E $_{beam}$ = 33 MeV and 38 MeV and the members of $γ$ -vibrational band have been identified. Results are compared with the systematic of this mass region and found in agreement. Observed band structures have been interpreted using the theoretical framework of microscopic triaxial projected shell model (TPSM) approach and it is shown that TPSM results are in fair agreement with the observed energies.
↳ nucl-exnucl-thEPJA(2019)·9 citations

Affiliations

first authorsco-authorsvia INSPIRE

Proper effective temperature of nonequilibrium steady state

Forward Elastic Scattering and Pomeron Models

The Quark-Gluon Vertex and the QCD Infrared Dynamics

Cross Sections for Inelastic 2-to-2 Meson-Meson Scattering in Hadronic Matter

γ-vibration in 198Hg

Affiliations

$γ$ -vibration in $^{198}$ Hg