Nuclear Theory·nucl-th

Friday·June 1, 2018

8 papers—4 primary·4 cross-listed

05
A percent-level determination of the nucleon axial coupling from Quantum Chromodynamics
Chia Cheng Chang🇺🇸 · Amy Nicholson🇺🇸 · Enrico Rinaldi🇺🇸 · Evan Berkowitz🇺🇸 · Nicolas Garron🇬🇧 · David A. Brantley🇺🇸 · Henry Monge-Camacho🇺🇸 · Christopher J. Monahan🇺🇸 · Chris Bouchard🇺🇸 · M.A. Clark🇺🇸 · Bálint Joó🇺🇸 · Thorsten Kurth🇺🇸 and 3 other authors
The $axial coupling of the nucleon$ , $g_{A}$ , is the strength of its coupling to the $weak$ axial current of the Standard Model of particle physics, in much the same way as the electric charge is the strength of the coupling to the electromagnetic current. This axial coupling dictates the rate at which neutrons decay to protons, the strength of the attractive long-range force between nucleons and other features of nuclear physics. Precision tests of the Standard Model in nuclear environments require a quantitative understanding of nuclear physics rooted in Quantum Chromodynamics, a pillar of the Standard Model. The prominence of $g_{A}$ makes it a benchmark quantity to determine theoretically - a difficult task because quantum chromodynamics is non-perturbative, precluding known analytical methods. Lattice Quantum Chromodynamics provides a rigorous, non-perturbative definition of quantum chromodynamics that can be implemented numerically. It has been estimated that a precision of two percent would be possible by 2020 if two challenges are overcome: contamination of $g_{A}$ from excited states must be controlled in the calculations and statistical precision must be improved markedly. Here we report a calculation of $g_{A}^{QC D} = 1.271 \pm 0.013$ , using an unconventional method inspired by the Feynman-Hellmann theorem that overcomes these challenges.
↳ hep-lathep-exhep-phnucl-ex+1Nature(2018)·237 citations
06
Measuring Color Memory in a Color Glass Condensate at Electron-Ion Colliders
Adam Ball🇺🇸 · Monica Pate🇺🇸 · Ana-Maria Raclariu🇺🇸 · Andrew Strominger🇺🇸 · Raju Venugopalan🇺🇸
The color memory effect is the non-abelian gauge theory analog of the gravitational memory effect, in which the passage of color radiation induces a net relative SU(3) color rotation of a pair of nearby quarks. It is proposed that this effect can be measured in the Regge limit of deeply inelastic scattering at electron-ion colliders.
↳ hep-phhep-thnucl-thAnnals Phys.(2019)·39 citations
07
Dispersive Corrections to the Born Approximation in Elastic Electron-Nucleus Scattering in the Intermediate Energy Regime
P. Gueye · A. A. Kabir J. Glister · B. W. Lee · R. Gilman · D. W. Higinbotham · E. Piasetzky · G. Ron · A. J. Sarty · S. Strauch · A. Adeyemi · K. Allada · W. Armstrong and 80 other authors
Measurements of elastic electron scattering data within the past decade have highlighted two-photon exchange contributions as a necessary ingredient in theoretical calculations to precisely evaluate hydrogen elastic scattering cross sections. This correction can modify the cross section at the few percent level. In contrast, dispersive effects can cause significantly larger changes from the Born approximation. The purpose of this experiment is to extract the carbon-12 elastic cross section around the first diffraction minimum, where the Born term contributions to the cross section are small to maximize the sensitivity to dispersive effects. The analysis uses the LEDEX data from the high resolution Jefferson Lab Hall A spectrometers to extract the cross sections near the first diffraction minimum of 12C at beam energies of 362 MeV and 685 MeV. The results are in very good agreement with previous world data, although with less precision. The average deviation from a static nuclear charge distribution expected from linear and quadratic fits indicate a 30.6% contribution of dispersive effects to the cross section at 1 GeV. The magnitude of the dispersive effects near the first diffraction minimum of 12C has been confirmed to be large with a strong energy dependence and could account for a large fraction of the magnitude for the observed quenching of the longitudinal nuclear response. These effects could also be important for nuclei radii extracted from parity-violating asymmetries measured near a diffraction minimum.
↳ nucl-exnucl-thEPJA(2020)·9 citations
08
Experimental and theoretical study of deuteron-proton elastic scattering for proton kinetic energies between $T_{p} = 882.2 MeV$ and $T_{p} = 918.3 MeV$
C. Fritzsch🇩🇪 · S. Barsov🇷🇺 · I. Burmeister🇩🇪 · S. Dymov🇩🇪 · R. Gebel🇩🇪 · M. Hartmann🇩🇪 · A. Kacharava🇩🇪 · A. Khoukaz🇩🇪 · V. Komarov🇷🇺 · P. Kulessa🇷🇺 · A. Kulikov🇵🇱 · V. I. Kukulin🇷🇺 and 15 other authors
New precise unpolarised differential cross sections of deuteron-proton elastic scattering have been measured at 16 different deuteron beam momenta between $p_{d} = 3120.17 MeV / c$ and $p_{d} = 3204.16 MeV / c$ at the COoler SYnchrotron COSY of the Forschungszentrum Jülich. The data, which were taken using the magnetic spectrometer ANKE, cover the equivalent range in proton kinetic energies from $T_{p} = 882.2 MeV$ to $T_{p} = 918.3 MeV$ . The experimental results are analysed theoretically using the Glauber diffraction model with accurate nucleon-nucleon input. The theoretical cross section at $T_{p} = 900 MeV$ agrees very well with the experimental one at low momentum transfers $∣ t ∣ < 0.2 (GeV / c)^{2}$ .
↳ nucl-exnucl-thPLB(2018)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE

A percent-level determination of the nucleon axial coupling from Quantum Chromodynamics

Measuring Color Memory in a Color Glass Condensate at Electron-Ion Colliders

Dispersive Corrections to the Born Approximation in Elastic Electron-Nucleus Scattering in the Intermediate Energy Regime

Experimental and theoretical study of deuteron-proton elastic scattering for proton kinetic energies between Tp​=882.2MeV and Tp​=918.3MeV

Affiliations

Experimental and theoretical study of deuteron-proton elastic scattering for proton kinetic energies between $T_{p} = 882.2 MeV$ and $T_{p} = 918.3 MeV$