Nuclear Theory·nucl-th

Tuesday·July 5, 2022

9 papers—8 primary·1 cross-listed

01
[Submitted on 1 Jul 2022]
Neutron skin of 48Ca deduced from interaction cross section
Masayuki Matsuzaki · Masanobu Yahiro
The neutron skin thickness of 48Ca was deduced from the interaction cross section by adopting a microscopic optical potential. The optical potential used was constructed by folding a chiral g matrix and the Skyrme mean-field densities renormalized by considering the information of the interaction cross section. The result was R_skin = 0.139 \pm 0.058 fm.
Comments:
Preprint version before acceptance of an article submitted for consideration in [Mod. Phys. Lett. A] [2022] [copyright World Scientific Publishing Company] [https://www.worldscientific.com/worldscinet/mpla]
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2207.00635 [pdf]
Mod.Phys.Lett.A(2022)·3 citations
02
[Submitted on 3 Jul 2022]
Towards Precise and Accurate Calculations of Neutrinoless Double-Beta Decay: Project Scoping Workshop Report
V. Cirigliano🇺🇸 · Z. Davoudi🇺🇸 · J. Engel🇺🇸 · R.J. Furnstahl🇺🇸 · G. Hagen🇺🇸 · U. Heinz🇺🇸 · H. Hergert🇺🇸 · M. Horoi🇺🇸 · C.W. Johnson🇺🇸 · A. Lovato🇺🇸 · E. Mereghetti🇺🇸 · W. Nazarewicz🇺🇸 and 11 other authors
We present the results of a National Science Foundation (NSF) Project Scoping Workshop, the purpose of which was to assess the current status of calculations for the nuclear matrix elements governing neutrinoless double-beta decay and determine if more work on them is required. After reviewing important recent progress in the application of effective field theory, lattice quantum chromodynamics, and ab initio nuclear-structure theory to double-beta decay, we discuss the state of the art in nuclear-physics uncertainty quantification and then construct a road map for work in all these areas to fully complement the increasingly sensitive experiments in operation and under development. The road map contains specific projects in theoretical and computational physics as well as an uncertainty-quantification plan that employs Bayesian Model Mixing and an analysis of correlations between double-beta-decay rates and other observables. The goal of this program is a set of accurate and precise matrix elements, in all nuclei of interest to experimentalists, delivered together with carefully assessed uncertainties. Such calculations will allow crisp conclusions from the observation or non-observation of neutrinoless double-beta decay, no matter what new physics is at play.
Comments:
This Project Scoping Workshop report is focused on the US context for the theory of neutrinloess double beta decay. Its authors plan to produce a journal article that addresses similar issues, but is more inclusive as regards non-US efforts on this problem. We would be happy to receive further input that will help us refine our text before it is submitted to the journal
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2207.01085 [pdf]
J.Phys.G(2022)·51 citations
03
[Submitted on 3 Jul 2022]
Generating Tensor Polarization from Shear Stress
David Wagner🇩🇪 · Nora Weickgenannt🇩🇪 · Enrico Speranza🇺🇸
We derive an expression for the tensor polarization of a system of massive spin-1 particles in a hydrodynamic framework. Starting from quantum kinetic theory based on the Wigner-function formalism, we employ a modified method of moments which also takes into account all spin degrees of freedom. It is shown that the tensor polarization of an uncharged fluid is determined by the shear-stress tensor. In order to quantify this novel polarization effect, we provide a formula which can be used for numerical calculations of vector-meson spin alignment in relativistic heavy-ion collisions.
Comments:
16 pages, 1 figure, Version accepted for publication in Physical Review Research
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2207.01111 [pdf]
PRResearch(2023)·52 citations
04
[Submitted on 4 Jul 2022]
Isoscaling constraining sources' sizes
S.R. Souza · R. Donangelo · W.G. Lynch · M.B. Tsang
In the framework of the Statistical Multifragmentation Model, the nuclear isoscaling analysis is extended to constrain the ratio between the sizes of the decaying sources formed in a collision between two heavy ions. It is found that the ratio between the probabilities of observing n fragments in each event, for each of the sources, follows a scaling law, similar to the traditional nuclear isoscaling. However, the corresponding slope is also sensitive to the sources' sizes. This property is explained analytically using the grand-canonical ensemble. The extent to which our findings are affected by finite size effects and by the deexcitation of the hot primary fragments is also investigated. The scaling turns out to be robust and weakly affected by effects implied by these two aspects. We also find that the Poisson distribution is a fairly good approximation to the above mentioned probabilities, associated with both the primordial fragments, produced at the breakup stage, and the final ones, found at the end of the fragment deexcitation process.
Comments:
6 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2207.01291 [pdf]
0 citations
05
[Submitted on 4 Jul 2022]
Multipole decomposition of tensor interactions of fermionic probes with composite particles and BSM signatures in nuclear reactions
Ayala Glick-Magid🇮🇱 · Doron Gazit🇮🇱
A multipole decomposition of a cross-section is a useful tool to simplify the analysis of reactions due to their symmetry properties. By using a new approach to decompose antisymmetric tensor-type interactions within the multipole analysis, we introduce a general mathematical formalism for working with tensor couplings. This allows us to present a general tensor nuclear response, which is particularly useful for ongoing beta-decay experiments looking for physics beyond the Standard Model, as well as other exotic particle scatterings off nuclei, e.g., in dark matter direct detection experiments. Using this method, beyond the Standard Model operators identify with the known Standard Model operators, eliminating the need for calculations of additional matrix elements. We present in detail BSM expressions useful for beta-decay experiments and give an exemplary application for 6He beta-decay, although the formalism is easily generalizable for calculating other exotic scattering reactions.
Comments:
39 pages, 1 figure
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2207.01357 [pdf]
PRD(2023)·13 citations
06
[Submitted on 4 Jul 2022]
Theoretical study of the d(d,p)3H and d(d,n)3He processes at low energies
M. Viviani (INFN-PI) · L. Girlanda (UniSalento & INFN-LE) · A. Kievsky (INFN-PI) · D. Logoteta (UniPI) · L.E. Marcucci (UniPI & INFN-PI)
We present a theoretical study of the processes d(d,p)3H and d(d,n)3He at energies of interest for energy production and for big-bang nucleosynthesis. We accurately solve the four body scattering problem using the ab-initio hyperspherical harmonic method, starting from nuclear Hamiltonians which include modern two- and three-nucleon interactions, derived in chiral effective field theory. We report results for the astrophysical factor, the quintet suppression factor, and various single and double polarized observables. An estimate of the "theoretical uncertainty" for all these quantities is provided by varying the cutoff parameter used to regularize the chiral interactions at high momentum.
Comments:
5 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2207.01433 [pdf]
PRL(2023)·5 citations
07
[Submitted on 4 Jul 2022]
Combining the in-medium similarity renormalization group with the density matrix renormalization group: Shell structure and information entropy
A. Tichai · S. Knecht · A.T. Kruppa · Ö. Legeza · C.P. Moca · A. Schwenk · M.A. Werner · G. Zarand
We propose a novel many-body framework combining the density matrix renormalization group (DMRG) with the valence-space (VS) formulation of the in-medium similarity renormalization group. This hybrid scheme admits for favorable computational scaling in large-space calculations compared to direct diagonalization. The capacity of the VS-DMRG approach is highlighted in ab initio calculations of neutron-rich nickel isotopes based on chiral two- and three-nucleon interactions, and allows us to perform converged ab initio computations of ground and excited state energies. We also study orbital entanglement in the VS-DMRG, and investigate nuclear correlation effects in oxygen, neon, and magnesium isotopes. The explored entanglement measures reveal nuclear shell closures as well as pairing correlations.
Comments:
5 pages, 4 Figures, version published at Phys. Lett. B
Subjects:
Nuclear Theory (nucl-th); Strongly Correlated Electrons (cond-mat.str-el); Quantum Physics (quant-ph)
arXiv:
2207.01438 [pdf]
PLB(2023)·60 citations
08
[Submitted on 4 Jul 2022]
Semi-microscopic theory of two proton emission
S.A. Ghinescu · D.S. Delion
We propose a semi-microscopic model for the simultaneous emission of two protons. This model has the advantage of avoiding certain technical aspects of a fully microscopic 3-body framework, while also allowing the investigation of the influence of proton pairing on the total lifetime of the decaying nucleus. Thus, we use the standard singlet two-proton wave function on the nuclear surface, provided by the Bardeen-Cooper-Schrieffer (BCS) approach, as a boundary condition for the propagator operator. Our model allows for the estimation of all quantities related to the $2 p$ emission process, since it provides the 3-body wave function over most of the domain. We show that reasonable agreement with experimental values can be reached by varying the $pp$ pairing strength outside the nucleus in an interval close to the "bare" singlet value.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2207.01475 [pdf]
PRC(2022)·3 citations
09
[Submitted on 4 Jul 2022] (cross-list from hep-ph)
Velocity of Sound beyond the High-Density Relativistic Limit from Lattice Simulation of Dense Two-Color QCD
Kei Iida🇯🇵 · Etsuko Itou🇯🇵
We obtain the equation of state (EoS) for two-color QCD at low temperature and high density from the lattice Monte Carlo simulation. We find that the velocity of sound exceeds the relativistic limit ( $c_{s}^{2} / c^{2} = 1/3$ ) after BEC-BCS crossover in the superfluid phase. Such an excess of the sound velocity is previously unknown from any lattice calculations for QCD-like theories. This finding might have a possible relevance to the EoS of neutron star matter revealed by recent measurements of neutron star masses and radii.
Comments:
4pages, 3figures, (ver2) Added discussions and corrected figure 2 and figure 3 following the mistake in the analysis (thanks to Simon Hands and Jon-Ivar Skullerud), (ver3) minor improvements, (ver4) minor improvements and references added
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2207.01253 [pdf]
PTEP(2022)·57 citations

Affiliations

first authorsco-authorsvia INSPIRE