Nuclear Theory·nucl-th

Thursday·May 4, 2017

10 papers—6 primary·4 cross-listed

07
[Submitted on 3 May 2017] (cross-list from physics.atom-ph)
Significance of distinct electron correlation effects in determining the P,T-odd electric dipole moment of $^{171}$ Yb
B. K. Sahoo🇰🇷 · Yashpal Singh🇰🇷
Parity and time-reversal violating electric dipole moment (EDM) of $^{171}$ Yb is calculated accounting for the electron correlation effects over the Dirac-Hartree-Fock (DHF) method in the relativistic Rayleigh-Schrödinger many-body perturbation theory, with the second (MBPT(2) method) and third order (MBPT(3) method) approximations, and two variants of all-order relativistic many-body approaches, in the random phase approximation (RPA) and coupled-cluster (CC) method with singles and doubles (CCSD method) framework. We consider electron-nucleus tensor-pseudotensor (T-PT) and nuclear Schiff moment (NSM) interactions as the predominant sources that induce EDM in a diamagnetic atomic system. Our results from the CCSD method to EDM ( $d_{a}$ ) of $^{171}$ Yb due to the T-PT and NSM interactions are found to be $d_{a} = 4.85 (6) \times 1 0^{- 20} ⟨ σ ⟩ C_{T} ∣ e ∣ c m$ and $d_{a} = 2.89 (4) \times 1 0^{- 17} S / (∣ e ∣ f m^{3})$ , respectively, where $C_{T}$ is the T-PT coupling constant and $S$ is the NSM. These values differ significantly from the earlier calculations. The reason for the same has been attributed to large correlation effects arising through non-RPA type of interactions among the electrons in this atom that are observed by analyzing the differences in the RPA and CCSD results. This has been further scrutinized from the MBPT(2) and MBPT(3) results and their roles have been demonstrated explicitly.
Comments:
11 pages, 4 figures and 4 tables
Subjects:
Atomic Physics (physics.atom-ph); Nuclear Theory (nucl-th); Computational Physics (physics.comp-ph); Quantum Physics (quant-ph)
arXiv:
1705.01283 [pdf]
PRA(2017)·8 citations
08
[Submitted on 3 May 2017] (cross-list from nucl-ex)
Experimental Determination of $η$ / $s$ for Finite Nuclear Matter
Debasish Mondal🇮🇳 · Deepak Pandit🇮🇳 · S. Mukhopadhyay🇮🇳 · Surajit Pal🇮🇳 · Balaram Dey🇮🇳 · Srijit Bhattacharya🇮🇳 · A. De🇮🇳 · Soumik Bhattacharya🇮🇳 · S. Bhattacharyya🇮🇳 · Pratap Roy🇮🇳 · K. Banerjee🇮🇳 · S. R. Banerjee🇮🇳
We present, for the first time, simultaneous determination of shear viscosity ( $η$ ) and entropy density ( $s$ ) and thus, $η / s$ for equilibrated nuclear systems from $A$ $\sim$ 30 to $A$ $\sim$ 208 at different temperatures. At finite temperature, $η$ is estimated by utilizing the $γ$ decay of the isovector giant dipole resonance populated via fusion evaporation reaction, while $s$ is evaluated from the nuclear level density parameter ( $a$ ) and nuclear temperature ( $T$ ), determined precisely by the simultaneous measurements of the evaporated neutron energy spectra and the compound nuclear angular momenta. The transport parameter $η$ and the thermodynamic parameter $s$ both increase with temperature resulting in a mild decrease of $η$ / $s$ with temperature. The extracted $η$ / $s$ is also found to be independent of the neutron-proton asymmetry at a given temperature. Interestingly, the measured $η$ / $s$ values are comparable to that of the high-temperature quark-gluon plasma, pointing towards the fact that strong fluidity may be the universal feature of the strong interaction of many-body quantum systems.
Comments:
Accepted for publication in Physical Review Letters, 6 pages, 4 figures
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1705.01286 [pdf]
PRL(2017)·30 citations
09
[Submitted on 3 May 2017] (cross-list from hep-ph)
Heavy and Strange Holographic Baryons
Yizhuang Liu🇺🇸 · Ismail Zahed🇺🇸
We extend the $D 4$ - $D 8$ holographic construction to include three chiral and one heavy flavor, to describe heavy-light baryons with strangeness and their exotics. At strong coupling, the heavy meson always binds to the bulk instanton in the form of a flavor zero mode in the fundamental representation. We quantize the ensuing bound states using the collective quantization method, to obtain the spectra of heavy and strange baryons with both explicit and hidden charm and bottom. Our results confirm the existence of two low-lying charmed penta-quark states with $\frac{1}{2}^{-}, \frac{3}{2}^{-}$ assignments, and predict many new ones with both charm and bottom. They also suggest a quartet of low-lying neutral $Ω_{c}^{0}$ with assignments $\frac{1}{2}^{\pm}, \frac{3}{2}^{\pm}$ that are heavier than the quintuplet of neutral $Ω_{c}^{0}$ recently reported by LHCb.
Comments:
14 pages, 1 figure. arXiv admin note: substantial text overlap with arXiv:1704.03412
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1705.01397 [pdf]
PRD(2017)·21 citations
10
[Submitted on 3 May 2017] (cross-list from hep-ph)
Quasi-PDFs, momentum distributions and pseudo-PDFs
A. V. Radyushkin🇺🇸
We show that quasi-PDFs may be treated as hybrids of PDFs and primordial rest-frame momentum distributions of partons. This results in a complicated convolution nature of quasi-PDFs that necessitates using large $p_{3} \sim 3$ GeV momenta to get reasonably close to the PDF limit. As an alternative approach, we propose to use pseudo-PDFs $P (x, z_{3}^{2})$ that generalize the light-front PDFs onto spacelike intervals and are related to Ioffe-time distributions $M (ν, z_{3}^{2})$ , the functions of the Ioffe time $ν = p_{3} z_{3}$ and the distance parameter $z_{3}^{2}$ with respect to which it displays perturbative evolution for small $z_{3}$ . In this form, one may divide out the $z_{3}^{2}$ dependence coming from the primordial rest-frame distribution and from the problematic factor due to lattice renormalization of the gauge link. The $ν$ -dependence remains intact and determines the shape of PDFs.
Comments:
6 pages, 3 figures, changes in text and references
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1705.01488 [pdf]
PRD(2017)·418 citations

Affiliations

first authorsco-authorsvia INSPIRE

Significance of distinct electron correlation effects in determining the P,T-odd electric dipole moment of 171Yb

Experimental Determination of η/s for Finite Nuclear Matter

Heavy and Strange Holographic Baryons

Quasi-PDFs, momentum distributions and pseudo-PDFs

Affiliations

Significance of distinct electron correlation effects in determining the P,T-odd electric dipole moment of $^{171}$ Yb

Experimental Determination of $η$ / $s$ for Finite Nuclear Matter