Nuclear Theory·nucl-th

Friday·June 24, 2016

8 papers—5 primary·3 cross-listed

01
[Submitted on 22 Jun 2016]
Magnetic hyperfine structure of the ground-state doublet in highly charged ions $^{229}$ Th $^{89 +, 87 +}$ and the Bohr-Weisskopf effect
E.V. Tkalya · A.V. Nikolaev
The magnetic hyperfine (MHF) structure of the $5/ 2^{+}$ (0.0 eV) ground state and the low-lying $3/ 2^{+}$ (7.8 eV) isomeric state of the $^{229}$ Th nucleus in highly charged ions Th $^{89 +}$ and Th $^{87 +}$ is calculated. The distribution of the nuclear magnetization (the Bohr-Weisskopf effect) is accounted for in the framework of the collective nuclear model with the wave functions of the Nilsson model for the unpaired neutron. The deviations of the MHF structure for the ground and isomeric states from their values in the model of point-like nuclear magnetic dipole are calculated. The influence of the mixing of the states with the same quantum number $F$ on the energy of sublevels is studied. Taking into account the mixing of states, the probabilities of the transitions between the components of MHF structure are found.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1606.07105 [pdf]
PRC(2016)·12 citations
02
[Submitted on 23 Jun 2016]
Quark-Pauli effects in three octet-baryons
C. Nakamoto🇯🇵 · Y. Suzuki🇯🇵
To sustain a neutron star with about two times the solar mass, multi baryons including hyperons are expected to produce repulsive effects in the interior of its high baryon-density region. To examine possible quark-Pauli repulsion among the baryons, we solve the eigenvalue problem of the quark antisymmetrizer for three octet-baryons that are described by most compact spatial configurations. We find that the Pauli blocking effect is weak in the $Λ nn$ system, while it is strong in the $Σ^{-} nn$ system. The appearance of the $Σ^{-}$ hyperon is suppressed in the neutron star interior but no quark-Pauli repulsion effectively works for the $Λ$ hyperon.
Comments:
9 pages, plus 7 pages as Supplemental Material
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1606.07225 [pdf]
PRC(2016)·8 citations
03
[Submitted on 23 Jun 2016]
Spectra and Electromagnetic Properties of the Neutron-Excess Nucleus $^{132}$ In
V. I. Isakov
Spectra of levels and transition rates are calculated for the odd--odd particle--hole neutron excess nucleus $^{132}$ In in the framework of the RPA approach.
Comments:
9 pages
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1606.07292 [pdf]
0 citations
04
[Submitted on 23 Jun 2016]
Transfer reaction code with nonlocal interactions
L. J. Titus · A. Ross · F. M. Nunes
We present a suite of codes (NLAT for nonlocal adiabatic transfer) to calculate the transfer cross section for single-nucleon transfer reactions, $(d, N)$ or $(N, d)$ , including nonlocal nucleon-target interactions, within the adiabatic distorted wave approximation. For this purpose, we implement an iterative method for solving the second order nonlocal differential equation, for both scattering and bound states. The final observables that can be obtained with NLAT are differential angular distributions for the cross sections of $A (d, N) B$ or $B (N, d) A$ . Details on the implementation of the T-matrix to obtain the final cross sections within the adiabatic distorted wave approximation method are also provided. This code is suitable to be applied for deuteron induced reactions in the range of $E_{d} = 10 - 70$ MeV, and provides cross sections with $4%$ accuracy.
Comments:
35 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1606.07341 [pdf]
Comput.Phys.Commun.(2016)·29 citations
05
[Submitted on 23 Jun 2016]
Examining the effect of nonlocality in $(d, n)$ transfer reactions
A. Ross · L. J. Titus · F. M. Nunes
Background: In the last year we have been exploring the effect of the explicit inclusion of nonlocality in (d,p) reactions. Purpose: The goal of this work is to extend previous studies to (d,n) reactions, which, although similar to (d,p), have specific properties that merit inspection. Method: We apply our methods (both the distorted wave Born approximation and the adiabatic wave approximation) to $(d, n)$ reactions on $^{16}$ O, $^{40}$ Ca, $^{48}$ Ca, $^{126}$ Sn, $^{132}$ Sn, and $^{208}$ Pb at $20$ and $50$ MeV. Results: We look separately at the modifications introduced by nonlocality in the final bound and scattering states, as well as the consequences reflected on the differential angular distributions. The cross sections obtained when using nonlocality explicitly are significantly different than those using the local approximation, just as in (d,p). Due to the particular role of Coulomb in the bound state, often we found the effects of nonlocality to be larger in (d,n) than in (d,p). Conclusions: Our results confirm the importance of including nonlocality explicitly in deuteron induced reactions.
Comments:
6 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1606.07344 [pdf]
PRC(2016)·16 citations
06
[Submitted on 22 Jun 2016] (cross-list from hep-ph)
Jet substructure using semi-inclusive jet functions within SCET
Zhong-Bo Kang🇺🇸 · Felix Ringer🇺🇸 · Ivan Vitev🇺🇸
We propose a new method to evaluate jet substructure observables in inclusive jet measurements, based upon semi-inclusive jet functions in the framework of Soft Collinear Effective Theory (SCET). As a first example, we consider the jet fragmentation function, where a hadron $h$ is identified inside a fully reconstructed jet. We introduce a new semi-inclusive fragmenting jet function $G_{i}^{h} (z = ω_{J} / ω, z_{h} = ω_{h} / ω_{J}, ω_{J}, R, μ)$ , which depends on the jet radius $R$ and the large light-cone momenta of the parton ` $i$ ' initiating the jet ( $ω$ ), the jet ( $ω_{J}$ ), and the hadron $h$ ( $ω_{h}$ ). The jet fragmentation function can then be expressed as a semi-inclusive observable, in the spirit of actual experimental measurements, rather than as an exclusive one. We demonstrate the consistency of the effective field theory treatment and standard perturbative QCD calculations of this observable at next-to-leading order (NLO). The renormalization group (RG) equation for the semi-inclusive fragmenting jet function $G_{i}^{h} (z, z_{h}, ω_{J}, R, μ)$ are also derived and shown to follow exactly the usual timelike DGLAP evolution equations for fragmentation functions. The newly obtained RG equations can be used to perform the resummation of single logarithms of the jet radius parameter $R$ up to next-to-leading logarithmic (NLL $_{R}$ ) accuracy. In combination with the fixed NLO calculation, we obtain NLO+NLL $_{R}$ results for the hadron distribution inside the jet. We present numerical results for $pp \to (jet h) X$ in the new framework, and find excellent agreement with existing LHC experimental data.
Comments:
28 pages, 6 figures, published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1606.07063 [pdf]
JHEP(2016)·113 citations
07
[Submitted on 22 Jun 2016] (cross-list from hep-ph)
Strange Quark Magnetic Moment of the Nucleon at Physical Point
Raza Sabbir Sufian🇺🇸 · Yi-Bo Yang🇺🇸 · Andrei Alexandru🇺🇸 · Terrence Draper🇺🇸 · Keh-Fei Liu🇺🇸 · Jian Liang🇺🇸
We report a lattice QCD calculation of the strange quark contribution to the nucleon's magnetic moment and charge radius. This analysis presents the first direct determination of strange electromagnetic form factors including at the physical pion mass. We perform a model-independent extraction of the strange magnetic moment and the strange charge radius from the electromagnetic form factors in the momentum transfer range of $0.051 GeV^{2} ≲ Q^{2} ≲ 1.31 GeV^{2}$ . The finite lattice spacing and finite volume corrections are included in a global fit with $24$ valence quark masses on four lattices with different lattice spacings, different volumes, and four sea quark masses including one at the physical pion mass. We obtain the strange magnetic moment $G_{M}^{s} (0) = - 0.064 (14) (09) μ_{N}$ . The four-sigma precision in statistics is achieved partly due to low-mode averaging of the quark loop and low-mode substitution to improve the statistics of the nucleon propagator. We also obtain the strange charge radius $⟨ r_{s}^{2} ⟩_{E} = - 0.0043 (16) (14)$ $fm^{2}$ .
Comments:
Published version in Physical Review Letters
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1606.07075 [pdf]
PRL(2017)·57 citations
08
[Submitted on 23 Jun 2016] (cross-list from quant-ph)
Decoherence and the Branching of Chaos-less Classical Trajectory
Takuji Ishikawa
This study was started to know mysterious classicality of nuclei. This time, I found a new rule for decoherence. I used a model without chaos. As a result, it was shown that not only the intersection of classical trajectories but also branching of classical trajectories are needed for decoherence. In other words, it was shown that interactions between a main system and environments have to make enough branchings of classical trajectories of the main system for decoherence.
Comments:
arXiv admin note: substantial text overlap with arXiv:1606.06282
Subjects:
Quantum Physics (quant-ph); Nuclear Theory (nucl-th)
arXiv:
1606.07098 [pdf]
0 citations

Affiliations

first authorsco-authorsvia INSPIRE