Nuclear Theory·nucl-th

Wednesday·October 9, 2019

12 papers—5 primary·7 cross-listed

01
[Submitted on 7 Oct 2019]
Color Correlations in the Proton
Gerald A. Miller🇺🇸
A general QCD light front formalism to compute many-body color charge correlation functions due to quarks in the proton was constructed~\cite{Dumitru:2018vpr}. These enable new studies of color charge distributions in the nucleon. The analogies between such correlation functions to electric and magnetization charge densities in the proton and also to nucleon-nucleon correlations in the nucleus are discussed. Including the color charge correlations leads naturally to the removal of infrared divergences that occurs in two- and three-gluon exchange interactions in $q q ˉ$ -proton scattering. Extensions to include gluonic color charge correlations are discussed.
Comments:
4 pages, 1 figure, to appear as part of proceedings of the ,INT program "Probing Nucleons and Nuclei in High Energy Collisions (INT ,18-3)". To be published by World Scientific
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1910.03006 [pdf]
0 citations
02
[Submitted on 7 Oct 2019]
Density-dependent NN-interaction from subsubleading chiral 3N-force: Intermediate-range contributions
N. Kaiser🇩🇪
From the subsubleading chiral three-nucleon force [intermediate-range contributions, published in Phys. Rev. C\,87, 054007 (2013)] a density-dependent NN-interaction $V_{med}$ is derived in isospin-symmetric nuclear matter. Following the division of the pertinent 3N-diagrams into two-pion-one-pion exchange topology and ring topology, one evaluates for these all selfclosings and concatenations of nucleon-lines to an in-medium loop. In the case of the $2 π 1 π$ -exchange topology, the momentum- and $k_{f}$ -dependent potentials associated with the isospin-operators ( $1$ and $τ_{1} \cdot τ_{2}$ ) and five independent spin-structures require at most one numerical integration. For the more challenging (concatenations of the) ring diagrams proportional to $c_{1, 2, 3, 4}$ , one ends up with regularized double-integrals $\int_{0}^{λ} d r r \int_{0}^{π /2} d ψ$ from which the $λ^{2}$ -divergence has been subtracted and the logarithmic piece $\sim ln (m_{π} / λ)$ is isolated. The derived semi-analytical results are most helpful to implement the subsubleading chiral 3N-forces into nuclear many-body calculations.
Comments:
17 pages, 1 figure, to be published in Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1910.03082 [pdf]
PRC(2020)·10 citations
03
[Submitted on 7 Oct 2019]
Time-Reversal-Invariance Violation in the $N d$ System and Large- $N_{C}$
Jared Vanasse🇺🇸 · Anna C. Bowman🇺🇸
A minimal set of five low energy constants (LECs) for time-reversal and parity violating ( $\neq T \neq P$ ) nucleon-nucleon ( $N N$ ) interactions at low energies ( $E < m_{π}^{2} / M_{N}$ ) is given. Using a large- $N_{C}$ (number of colors in QCD) analysis we show that one linear combination of LECs is $O (N_{C})$ , three LECs are $O (N_{C}^{0})$ , and one linear combination of LECs is $O (N_{C}^{- 1})$ . We also calculate the $\neq T \neq P$ observables of neutron spin rotation through a polarized deuteron target and a spin correlation coefficient in nucleon-deuteron scattering using pionless effective field theory. Using the large- $N_{C}$ analysis we show that the spin correlation coefficient and the neutron spin rotation are predominantly determined by same two LECs in the large- $N_{C}$ basis.
Comments:
22 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1910.03133 [pdf]
PRC(2023)·10 citations
04
[Submitted on 8 Oct 2019]
Unblocking of stellar electron capture for neutron-rich $N = 50$ nuclei at finite temperature
Alan A. Dzhioev · K. Langanke · G. Martínez-Pinedo · A. I. Vdovin · Ch. Stoyanov
We have calculated electron capture rates for neutron-rich $N = 50$ nuclei ( $^{78}$ Ni, $^{82}$ Ge, $^{86}$ Kr, $^{88}$ Sr) within the Thermal QRPA approach at temperatures $T = 0$ , corresponding to capture on the ground-state, and at $T = 10$ GK (0.86 MeV), which is a typical temperature at which the $N = 50$ nuclei are abundant during a supernova collapse. In agreement with recent experiments, we find no Gamow-Teller (GT $_{+}$ ) strength at low excitation energies, $E < 7$ MeV, caused by Pauli blocking induced by the $N = 50$ shell gap. At the astrophysically relevant temperatures this Pauli blocking of the GT $_{+}$ strength is overcome by thermal excitations across the $Z = 40$ proton and $N = 50$ neutron shell gaps, leading to a sizable GT contribution to the electron capture. At the high densities, at which the $N = 50$ nuclei are important for stellar electron capture, forbidden transitions contribute noticeably to the capture rate. Our results indicate that the neutron-rich $N = 50$ nuclei do not serve as an obstacle of electron capture during the supernova collapse.
Comments:
Published version
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1910.03335 [pdf]
PRC(2020)·34 citations
05
[Submitted on 8 Oct 2019]
Lifetime estimations and a non-monotonic initial energy density in heavy ion collisions at RHIC and LHC
G. Kasza🇭🇺 · T. Csorgo🇭🇺
We highlight some connections between the final state hadronic observables and the initial conditions using a recently found new exact family of solutions of relativistic hydrodynamics. These relations provide explicit examples of the scaling behaviour in relativistic hydrodynamics and may provide an advanced estimate of the lifetime and the initial energy density in $s_{N N} = 62.4$ , $130$ , and $200$ GeV Au+Au collisions at RHIC and $s_{N N} = 5.0$ TeV Pb+Pb and $5.44$ TeV Xe+Xe as well as $s = 7$ , $8$ and $13$ TeV p+p collisions at LHC energies. A surprising result is that these advanced estimates yield a non-monotonic increase of the initial energy density with increasing collision energy at the RHIC energy range.
Comments:
8 pages, 5 figures, talk of G. Kasza at the WPCF 2019 conference at JINR, Dubna, Russia, submitted to the proceedings. Physics of Elementary Particles and Nuclei (PEPAN), in press
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1910.03428 [pdf]
Phys.Part.Nucl.(2020)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE

Color Correlations in the Proton

Density-dependent NN-interaction from subsubleading chiral 3N-force: Intermediate-range contributions

Time-Reversal-Invariance Violation in the Nd System and Large-NC​

Unblocking of stellar electron capture for neutron-rich N=50 nuclei at finite temperature

Lifetime estimations and a non-monotonic initial energy density in heavy ion collisions at RHIC and LHC

Affiliations

Time-Reversal-Invariance Violation in the $N d$ System and Large- $N_{C}$

Unblocking of stellar electron capture for neutron-rich $N = 50$ nuclei at finite temperature