Nuclear Theory·nucl-th

Friday·May 22, 2015

6 papers—2 primary·4 cross-listed

01
[Submitted on 21 May 2015]
$^{10}$ B+ $α$ states with chain-like structures in $^{14}$ N
Yoshiko Kanada-En'yo
I investigate $^{10}$ B+ $α$ cluster states of $^{14}$ N with a $^{10}$ B+ $α$ cluster model. Near the $α$ -decay threshold energy, I obtain $K^{π} = 3^{+}$ and $K^{π} = 1^{+}$ rotational bands having $^{10}$ B( $3^{+}$ )+ $α$ and $^{10}$ B( $1^{+}$ )+ $α$ components, respectively. I assign the band-head state of the $K^{π} = 3^{+}$ band to the experimental $3^{+}$ at $E_{x}$ =13.19 MeV of $^{14}$ N observed in $α$ scattering reactions by $^{10}$ B and show that the calculated $α$ -decay width is consistent with the experimental data. I discuss an $α$ -cluster motion around the $^{10}$ B cluster and show that $^{10}$ B+ $α$ cluster states contain significant components of a linear-chain 3 $α$ configuration, in which an $α$ cluster is localized in the longitudinal direction around the deformed $^{10}$ B cluster.
Comments:
14 pages, 11 figures, 2 tables
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1505.05591 [pdf]
PRC(2015)·5 citations
02
[Submitted on 21 May 2015]
Collective aspects deduced from time-dependent microscopic mean-field with pairing: application to the fission process
Yusuke Tanimura · Denis Lacroix · Guillaume Scamps
Given a set of collective variables, a method is proposed to obtain the associated conjugated collective momenta and masses starting from a microscopic time-dependent mean-field theory. The construction of pairs of conjugated variables is the first step to bridge microscopic and macroscopic approaches. The method is versatile and can be applied to study a large class of nuclear processes. An illustration is given here with the fission of $^{258}$ Fm. Using the quadrupole moment and eventually higher-order multipole moments, the associated collective masses are estimated along the microscopic mean-field evolution. When more than one collective variable are considered, it is shown that the off-diagonal matrix elements of the inertia play a crucial role. Using the information on the quadrupole moment and associated momentum, the collective evolution is studied. It is shown that dynamical effects beyond the adiabatic limit are important. Nuclei formed after fission tend to stick together for longer time leading to a dynamical scission point at larger distance between nuclei compared to the one anticipated from the adiabatic energy landscape. The effective nucleus-nucleus potential felt by the emitted nuclei is finally extracted.
Comments:
12 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1505.05647 [pdf]
PRC(2015)·50 citations
03
[Submitted on 20 May 2015] (cross-list from hep-lat)
Lattice QCD at Non-Zero Temperature
Alexei Bazavov🇺🇸
This is a review of selected recent developments in finite-temperature lattice QCD. The focus is on the properties of the chiral crossover region, deconfinement and fluctuations of conserved charges, the equation of state, properties of heavy quarkonia and reconstruction of spectral functions.
Comments:
20 pages, 23 figures, plenary talk presented at the 32nd International Symposium on Lattice Field Theory, June 23-28, 2014, Columbia University, New York City, NY
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1505.05543 [pdf]
6 citations
04
[Submitted on 21 May 2015] (cross-list from hep-ph)
Nucleon-Antinucleon Annhiliation at Large Nc
Thomas D. Cohen🇺🇸 · Brian Mc Peak🇺🇸 · Bendeguz Offertaler🇺🇸
Nucleon-antinucleon annihilation in the large $N_{c}$ limit of QCD in the Witten regime of fixed velocity is considered with a focus on the spin and isospin dependence of the annihilation cross-section. In general, time-reversal and isospin invariance restricts the annihilation cross-section to depend on 6 independent energy-dependent terms. At large $N_{c}$ , a spin-flavor symmetry emerges in the theory that acts to further restrict the dependence of the annihilation cross-section to three of these terms; the other terms amount to $1/ N_{c}$ corrections. Assuming dominance of the leading order terms, several identities are derived that relate annihilation in different spin-isospin channels. A key prediction is that for unpolarized nucleons in Witten kinematics, the proton-antiproton annihilation cross-section should be equal to the proton-antineutron annihilation cross-section up to corrections of relative order $1/ N_{c}$ . Unpolarized nucleon-antinucleon annihilation data appears to be consistent with this expectation.
Comments:
Minor typos fixed in new version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1505.05638 [pdf]
PRC(2015)·1 citation
05
[Submitted on 21 May 2015] (cross-list from hep-lat)
Polyakov loop fluctuations in Dirac eigenmode expansion
Takahiro M. Doi🇯🇵 · Krzysztof Redlich🇵🇱 · Chihiro Sasaki🇵🇱 · Hideo Suganuma🇯🇵
We investigate correlations of the Polyakov loop fluctuations with eigenmodes of the lattice Dirac operator. Their analytic relations are derived on the temporally odd-number size lattice with the normal non-twisted periodic boundary condition for the link-variables. We find that the low-lying Dirac modes yield negligible contributions to the Polyakov loop fluctuations. This property is confirmed to be valid in confined and deconfined phase by numerical simulations in SU(3) quenched QCD. These results indicate that there is no direct, one-to-one correspondence between confinement and chiral symmetry breaking in QCD in the context of different properties of the Polyakov loop fluctuation ratios.
Comments:
9 pages, 5 figures
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1505.05752 [pdf]
PRD(2015)·13 citations
06
[Submitted on 21 May 2015] (cross-list from hep-ph)
Electroproduction of the $N^{*} (1535)$ nucleon resonance in QCD
I.V. Anikin🇷🇺 · V.M. Braun🇩🇪 · N. Offen🇩🇪
Following the 12 GeV upgrade, a dedicated experiment is planned with the Hall B CLAS12 detector at Jefferson Lab, with the aim to study electroproduction of nucleon resonances at high photon virtualities up to $Q^{2} = 12$ GeV $^{2}$ . In this work we present a QCD-based approach to the theoretical interpretation of these upcoming results in the framework of light-cone sum rules that combine perturbative calculations with dispersion relations and duality. The form factors are thus expressed in terms of $N^{*} (1535)$ light-front wave functions at small transverse separations, called distribution amplitudes. The distribution amplitudes can therefore be determined from the comparison with the experimental data on form factors and compared to the results of lattice QCD simulations. The results of the corresponding next-to-leading order calculation are presented and compared with the existing data. We find that the form factors are dominated by the twist-four distribution amplitudes that are related to the $P$ -wave three-quark wave functions of the $N^{*} (1535)$ , i.e. to contributions of orbital angular momentum.
Comments:
12 pages, 3 figures. arXiv admin note: text overlap with arXiv:1310.1375 (2 typos corrected 1 reference updated)
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1505.05759 [pdf]
PRD(2015)·41 citations

Affiliations

first authorsco-authorsvia INSPIRE

10B+α states with chain-like structures in 14N

Collective aspects deduced from time-dependent microscopic mean-field with pairing: application to the fission process

Lattice QCD at Non-Zero Temperature

Nucleon-Antinucleon Annhiliation at Large Nc

Polyakov loop fluctuations in Dirac eigenmode expansion

Electroproduction of the N∗(1535) nucleon resonance in QCD

Affiliations

$^{10}$ B+ $α$ states with chain-like structures in $^{14}$ N

Electroproduction of the $N^{*} (1535)$ nucleon resonance in QCD