Nuclear Theory·nucl-th

Thursday·June 22, 2017

4 papers—2 primary·2 cross-listed

01
[Submitted on 20 Jun 2017]
Reconciling Coulomb breakup and neutron radiative capture
Pierre Capel · Yvan Nollet
The Coulomb-breakup method to extract the cross section for neutron radiative capture at astrophysical energies is analyzed in detail. In particular, its sensitivity to the description of the neutron-core continuum is ascertained. We consider the case of 14C(n, $γ$ )15C for which both the radiative capture at low energy and the Coulomb breakup of 15C into 14C+n on Pb at 68 MeV/nucleon have been measured with accuracy. We confirm the direct proportionality of the cross section for both reactions to the square of the asymptotic normalization constant of 15C observed by Summers and Nunes [Phys. Rev. C 78, 011601 (2008)], but we also show that the 14C-n continuum plays a significant role in the calculations. Fortunately, the method proposed by Summers and Nunes can be improved to absorb that continuum dependence. We show that a more precise radiative-capture cross section can be extracted selecting the breakup data at forward angles and low 14C-n relative energies.
Comments:
Erratum added in the Appendix A
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1706.06606 [pdf]
PRC(2017)·12 citations
02
[Submitted on 21 Jun 2017]
Accuracy of the lepton-nucleus scattering models in the quasielastic region
Joanna Ewa Sobczyk🇵🇱
We present a discussion of models of nuclear effects used to describe an inclusive electron-nucleus scattering in the quasielastic (QE) peak region, aiming to compare them and draw conclusion of their reliability when applied in neutrino-nucleus interactions. A basic motivation is to reduce systematic errors in neutrino oscillation experiments. We concentrate on the neutrino energy profile of the T2K experiment, which provides us a region of the greatest importance in terms of the highest contribution to the charge-current quasielastic (CCQE) cross section. We choose only electron-nucleus data that overlaps with this region. In order to clearify the analysis, we split the data sets into three groups and draw conclusion separately from each one of them. We selected six models for this comparison: Benhar's spectral function with and without final state interaction (Benhar's SF+FSI), Valencia spectral function (Valencia SF), for higher energy transfer only with the hole spectral function; GiBUU and also the local and global Fermi gas models. The latter two are included as a benchmark to quantify the effect of various nuclear effects. All the six models are often used in neutrino scattering studies. A short theoretical description of each model is given. Although in the selected data sets the QE mechanism dominates, we also briefly discuss a possible impact of $2 p 2 h$ and $Δ$ contributions.
Comments:
23 pages, 49 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1706.06739 [pdf]
PRC(2017)·26 citations
03
[Submitted on 18 Jun 2017] (cross-list from hep-ph)
Decuplet to octet baryon transitions in chiral perturbation theory
Hao-Song Li🇨🇳 · Zhan-Wei Liu🇨🇳 · Xiao-Lin Chen🇨🇳 · Wei-Zhen Deng🇨🇳 · Shi-Lin Zhu🇨🇳
We have systematically investigated the decuplet (T) to octet (B) baryon ( $T \to B γ$ ) transition magnetic moments to the next-to-next-to-leading order and electric quadruple moments to the next-to-leading order in the framework of the heavy baryon chiral perturbation theory. Our calculation includes the contributions from both the intermediate decuplet and octet baryon states in the loops. Our results show reasonably good convergence of the chiral expansion and agreement with the experimental data. The analytical expressions may be useful to the chiral extrapolation of the lattice simulations of the decuplet electromagnetic properties.
Comments:
20 pages, 2 figures. arXiv admin note: substantial text overlap with arXiv:1608.04617
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1706.06458 [pdf]
EPJC(2019)·19 citations
04
[Submitted on 21 Jun 2017] (cross-list from hep-ph)
Nuclear modification of forward $D$ production in pPb collisions at the LHC
Hirotsugu Fujii🇯🇵 · Kazuhiro Watanabe🇺🇸
We study nuclear modification factors for single $D$ meson and semileptonic decay lepton $l$ ( $= e, μ$ ) production in minimum bias proton-nucleus (p $A$ ) collisions at the LHC in the color-glass-condensate (CGC) framework at leading order in strong coupling. In our numerical computations, transverse momentum ( $k_{⊥}$ ) dependent multi-point Wilson line correlators are employed for describing target nucleus for p $A$ and proton for pp. The projectile proton is treated with unintegrated gluon distribution function, which is also $k_{⊥}$ -dependent. The rapidity evolutions of these functions in the small Bjorken $x$ region are taken into account by solving running coupling Balitsky-Kovchegov (BK) equation at leading logarithmic accuracy. For simplicity, we employ Kartvelishvili's type fragmentation function and a simple model for lepton energy distribution from seileptonic decay, respectively, to compute differential cross sections for $D$ and $l$ production. The gluon saturation scale inside the heavy nucleus is enhanced and dependent on $x$ , which we take into account by replacing the initial saturation scale in the BK equation with a larger value for the heavy nucleus. We show that the saturation effect leads to perceptible nuclear suppression of $D$ production at forward rapidity. Our numerical results predict similar nuclear suppressions in p $A$ collisions for forward $l$ production at lower transverse momentum $p_{⊥} < 2 GeV$ . Numerical tables on the nuclear modifications of $D$ and $l$ are listed in this note.
Comments:
12 pages, 3 figures; v2: typo in (3) corrected
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1706.06728 [pdf]
21 citations

Affiliations

first authorsco-authorsvia INSPIRE

Reconciling Coulomb breakup and neutron radiative capture

Accuracy of the lepton-nucleus scattering models in the quasielastic region

Decuplet to octet baryon transitions in chiral perturbation theory

Nuclear modification of forward D production in pPb collisions at the LHC

Affiliations

Nuclear modification of forward $D$ production in pPb collisions at the LHC