Nuclear Theory·nucl-th

Tuesday·February 19, 2019

12 papers—8 primary·4 cross-listed

09
Comparing proton momentum distributions in $A = 2$ and 3 nuclei via $^{2}$ H $^{3}$ H and $^{3}$ He $(e, e^{'} p)$ measurements
R. Cruz-Torres🇺🇸 · S. Li🇺🇸 · F. Hauenstein🇺🇸 · A. Schmidt🇺🇸 · D. Nguyen🇺🇸 · D. Abrams🇺🇸 · H. Albataineh🇺🇸 · S. Alsalmi🇺🇸 · D. Androic🇭🇷 · K. Aniol🇺🇸 · W. Armstrong🇺🇸 · J. Arrington🇺🇸 and 116 other authors
We report the first measurement of the $(e, e^{'} p)$ reaction cross-section ratios for Helium-3 ( $^{3}$ He), Tritium ( $^{3}$ H), and Deuterium ( $d$ ). The measurement covered a missing momentum range of $40 \leq p_{mi ss} \leq 550$ MeV $/ c$ , at large momentum transfer ( $⟨ Q^{2} ⟩ \approx 1.9$ (GeV $/ c$ ) $^{2}$ ) and $x_{B} > 1$ , which minimized contributions from non quasi-elastic (QE) reaction mechanisms. The data is compared with plane-wave impulse approximation (PWIA) calculations using realistic spectral functions and momentum distributions. The measured and PWIA-calculated cross-section ratios for $^{3}$ He $/ d$ and $^{3}$ H $/ d$ extend to just above the typical nucleon Fermi-momentum ( $k_{F} \approx 250$ MeV $/ c$ ) and differ from each other by $\sim 20%$ , while for $^{3}$ He/ $^{3}$ H they agree within the measurement accuracy of about 3\%. At momenta above $k_{F}$ , the measured $^{3}$ He/ $^{3}$ H ratios differ from the calculation by $20% - 50%$ . Final state interaction (FSI) calculations using the generalized Eikonal Approximation indicate that FSI should change the $^{3}$ He/ $^{3}$ H cross-section ratio for this measurement by less than 5\%. If these calculations are correct, then the differences at large missing momenta between the $^{3}$ He/ $^{3}$ H experimental and calculated ratios could be due to the underlying $N N$ interaction, and thus could provide new constraints on the previously loosely-constrained short-distance parts of the $N N$ interaction.
↳ nucl-exnucl-thPLB(2019)·28 citations
10
Relativistic Quantum Kinetic Theory for Massive Fermions and Spin Effects
Jian-Hua Gao🇨🇳 · Zuo-Tang Liang🇨🇳
We present the complete first order relativistic quantum kinetic theory with spin for massive fermions derived from the Wigner function formalism in a concise form that shows explicitly how the 32 Wigner equations reduce to 4 independent transport equations. We solve modified on-shell conditions to obtain the general solution and present the corresponding transport equations in three different forms that are suitable for different purposes. We demonstrate how different spin effects arise from the kinetic theory by calculating the chiral separation effect with mass correction, the chiral anomaly from the axial current and the quantum magnetic moment density induced by vorticity and magnetic field. We also show how to generate the global polarization effect due to spin vorticity coupling. The formalism presented may serve as a practical theoretical framework to study different spin effects in relativistic fermion systems encountered in different areas such as heavy ion, astro-particle and condensed matter physics as well.
↳ hep-phhep-thnucl-thPRD(2019)·160 citations
11
Ultra-peripheral-collision studies in the fixed-target mode with the proton and lead LHC beams
N. Yamanaka🇫🇷 · C. Hadjidakis🇫🇷 · D. Kikola🇵🇱 · J.P. Lansberg🇫🇷 · L. Massacrier🇫🇷 · M.G. Echevarria🇮🇹 · A. Kusina🇵🇱 · I. Schienbein🇫🇷 · J. Seixas🇵🇹 · H.S. Shao🇫🇷 · A. Signori🇺🇸 · B. Trzeciak🇳🇱 and 21 other authors
We address the physics case related to the studies of ultra-peripheral pH, pPb, PbH, and PbPb collisions in the fixed-target mode at the LHC. In particular, we discuss how one can measure the gluon generalized parton distribution E_g(x,xi,t) in exclusive J/psi photoproduction with a transversely polarized hydrogen target.
↳ hep-exhep-phnucl-exnucl-thPoS(2019)·1 citation
12
Lattice-based equation of state at finite baryon number, electric charge and strangeness chemical potentials
J. Noronha-Hostler🇺🇸 · P. Parotto🇺🇸 · C. Ratti🇺🇸 · J. M. Stafford🇺🇸
We construct an equation of state for Quantum Chromodynamics (QCD) at finite temperature and chemical potentials for baryon number $B$ , electric charge $Q$ and strangeness $S$ . We use the Taylor expansion method, up to the fourth power for the chemical potentials. This requires the knowledge of all diagonal and non-diagonal $B QS$ correlators up to fourth order: these results recently became available from lattice QCD simulations, albeit only at a finite lattice spacing $N_{t} = 12$ . We smoothly merge these results to the Hadron Resonance Gas (HRG) model, to be able to reach temperatures as low as 30 MeV; in the high temperature regime, we impose a smooth approach to the Stefan-Boltzmann limit. We provide a parameterization for each one of these $B QS$ correlators as functions of the temperature. We then calculate pressure, energy density, entropy density, baryonic, strangeness, electric charge densities and compare the two cases of strangeness neutrality and $μ_{S} = μ_{Q} = 0$ . We also calculate the isentropic trajectories and compare them in the two cases. Our equation of state can be readily used as an input of hydrodynamical simulations of matter created at the Relativistic Heavy Ion Collider (RHIC).
↳ hep-phnucl-thPRC(2019)·97 citations

Affiliations

first authorsco-authorsvia INSPIRE

Comparing proton momentum distributions in A=2 and 3 nuclei via 2H 3H and 3He (e,e′p) measurements

Relativistic Quantum Kinetic Theory for Massive Fermions and Spin Effects

Ultra-peripheral-collision studies in the fixed-target mode with the proton and lead LHC beams

Lattice-based equation of state at finite baryon number, electric charge and strangeness chemical potentials

Affiliations

Comparing proton momentum distributions in $A = 2$ and 3 nuclei via $^{2}$ H $^{3}$ H and $^{3}$ He $(e, e^{'} p)$ measurements