Nuclear Theory·nucl-th

Monday·October 3, 2016

8 papers—4 primary·4 cross-listed

01
[Submitted on 30 Sept 2016]
The effect of neutron skin on inclusive prompt photon production in Pb~+~Pb collisions at the LHC
Somnath De🇮🇳
Recent experiments on lead (\textrm{ $P b_{82}^{208}$ }) nuclei have observed the celebrated phenomenon of neutron skin-thickness of low energy nuclear physics. The skin-thickness provides a measure of extension of spatial distribution of neutrons inside the atomic nucleus than protons. We have studied the effect of neutron skin-thickness on inclusive prompt photon production in Pb~+~Pb collisions at the Large Hadron Collider energies. We have calculated the \textquoteleft central-to-peripheral ratio\textquoteright ( $R_{cp}$ ) of prompt photon production with and without accounting for neutron skin effect. The neutron skin causes a characteristic enhancement in the ratio, in particular at forward rapidity, which is distinguishable in our calculation. However a very precise direct photon measurement up to large transverse momenta would be necessary to constrain the feature in experiment.
Comments:
10 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1609.09608 [pdf]
J.Phys.G(2017)·9 citations
02
[Submitted on 30 Sept 2016]
Structural evolution in $A \approx 100$ nuclei within the mapped interacting boson model based on the Gogny energy density functional
K. Nomura · R. Rodríguez-Guzmán · L. M. Robledo
The structure of even-even neutron-rich Ru, Mo, Zr and Sr nuclei in the $A \approx 100$ mass region is studied within the interacting boson model (IBM) with microscopic input from the self-consistent mean-field approximation based on the Gogny-D1M energy density functional. The deformation energy surface in the quadrupole deformation space $(β, γ)$ , computed within the constrained Hartree-Fock-Bogoliubov framework, is mapped onto the expectation value of the appropriately chosen IBM Hamiltonian with configuration mixing in the boson condensate state. The mapped IBM Hamiltonian is used to study the spectroscopic properties of $^{98 - 114}$ Ru, $^{96 - 112}$ Mo, $^{94 - 110}$ Zr and $^{92 - 108}$ Sr. Several cases of $γ$ -soft behavior are predicted in Ru and Mo nuclei while a pronounced coexistence between strongly-prolate and weakly-oblate deformed shapes is found for Zr and Sr nuclei. The method describes well the evolution of experimental yrast and non-yrast states as well as selected $B$ (E2) transition probabilities.
Comments:
20 pages, 23 figures, 1 table; To be published in Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1609.09614 [pdf]
PRC(2016)·101 citations
03
[Submitted on 30 Sept 2016]
How to Measure Squeeze Out
R.S. Longacre🇺🇸
Squeeze out happen when the expanding central fireball flows around a large surface flux tube in a central Au-Au collision at RHIC. We model such an effect in a flux tube model. Two particle correlations with respect to the $v_{2}$ axis formed by the soft fireball particles flowing around this large flux tube is a way of measuring the effect.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1609.09848 [pdf]
3 citations
04
[Submitted on 30 Sept 2016]
Reverse engineering nuclear properties from rare earth abundances in the $r$ process
M. R. Mumpower · G. C. McLaughlin · R. Surman · A. W. Steiner
The bulk of the rare earth elements are believed to be synthesized in the rapid neutron capture process or $r$ process of nucleosynthesis. The solar $r$ -process residuals show a small peak in the rare earths around $A \sim 160$ , which is proposed to be formed dynamically during the end phase of the $r$ process by a pileup of material. This abundance feature is of particular importance as it is sensitive to both the nuclear physics inputs and the astrophysical conditions of the main $r$ process. We explore the formation of the rare earth peak from the perspective of an inverse problem, using Monte Carlo studies of nuclear masses to investigate the unknown nuclear properties required to best match rare earth abundance sector of the solar isotopic residuals. When nuclear masses are changed, we recalculate the relevant $β$ -decay properties and neutron capture rates in the rare earth region. The feedback provided by this observational constraint allows for the reverse engineering of nuclear properties far from stability where no experimental information exists. We investigate a range of astrophysical conditions with this method and show how these lead to different predictions in the nuclear properties influential to the formation of the rare earth peak. We conclude that targeted experimental campaigns in this region will help to resolve the type of conditions responsible for the production of the rare earth nuclei, and will provide new insights into the longstanding problem of the astrophysical site(s) of the $r$ process.
Comments:
34 pages, 14 figures
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
1609.09858 [pdf]
J.Phys.G(2017)·46 citations

Affiliations

first authorsco-authorsvia INSPIRE

The effect of neutron skin on inclusive prompt photon production in Pb~+~Pb collisions at the LHC

Structural evolution in A≈100 nuclei within the mapped interacting boson model based on the Gogny energy density functional

How to Measure Squeeze Out

Reverse engineering nuclear properties from rare earth abundances in the r process

Affiliations

Structural evolution in $A \approx 100$ nuclei within the mapped interacting boson model based on the Gogny energy density functional

Reverse engineering nuclear properties from rare earth abundances in the $r$ process