Nuclear Theory·nucl-th

Friday·January 21, 2022

13 papers—5 primary·8 cross-listed

01
[Submitted on 20 Jan 2022]
The $^{6}$ Li $(p, γ)^{7}$ Be reaction rate in the light of the new LUNA data
S. B. Dubovichenko · A. S. Tkachenko · R. Ya. Kezerashvili · N. A. Burkova · A. V. Dzhazairov-Kakhramanov
We present new calculations of the astrophysical $S -$ factor and reaction rate for the $^{6}$ Li $(p, γ)^{7}$ Be reaction at energies of 10 keV to 5 MeV in the framework of a modified potential cluster model with forbidden states, including low lying resonances. The astrophysical $S (E) -$ factor is compared with the available experimental data and calculations done within different models. The results for the $S -$ factor are in good agreement with the data set (for $E < 0.3$ MeV) and calculations (for $E < 0.6$ MeV) of LUNA collaboration (Phys. Rev. C 102 $,$ 052802, 2020). The recommended extrapolated zero value $S (0)$ turned out to be 101 eV $\cdot$ b. Using the theoretical total cross-sections $,$ the $^{6}$ Li $(p, γ)^{7}$ Be capture reaction rate is calculated at temperatures ranging from 0.01 to 10 $T_{9}$ and compared with NACRE and NACRE II. Analytical expressions for the $S -$ factor and reaction rate are given, and the effect of low-lying resonances on the reaction rate is estimated. We suggest to update the NACRE and NACRE II databases in light of the new LUNA data and present calculations.
Comments:
17 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2201.07987 [pdf]
PRC(2022)·17 citations
02
[Submitted on 20 Jan 2022]
Sub-barrier fusion reactions
K. Hagino
The concept of compound nucleus was proposed by Niels Bohr in 1936 to explain narrow resonances observed in scattering of a slow neutron off atomic nuclei. A compound nucleus is a metastable state with a long lifetime, in which all the degrees of freedom are in a sort of thermal equilibrium. Fusion reactions are defined as reactions to form such compound nucleus by merging two atomic nuclei. Here a short description of heavy-ion fusion reactions at energies close the Coulomb barrier is presented. This includes: (i) an overview of a fusion process, (ii) a strong interplay between nuclear structure and fusion, (iii) fusion and multi-dimensional/multi-particle quantum tunneling, and (iv) fusion for superheavy elements.
Comments:
26 pages, 19 figures. Contribution to the "Handbook of Nuclear Physics", Springer, 2022, I. Tanihata, H. Toki and T. Kajino, eds
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2201.08061 [pdf]
5 citations
03
[Submitted on 20 Jan 2022]
Strangeness $S = - 3$ and $- 4$ baryon-baryon interactions in chiral effective field theory
J. Haidenbauer🇩🇪 · U.-G. Meißner🇩🇪
Studies of the baryon-baryon interaction involving hyperons within chiral effective field theory, so far performed up to next-to-leading order (NLO) in the chiral expansion, have shown that for the strangeness $S = - 1$ ( $Λ N$ , $Σ N$ ) and $S = - 2$ ( $ΛΛ$ , $Ξ N$ ) sectors a consistent and satisfactory description of the available scattering data and experimental constraints can be achieved based on the assumption of broken SU(3) flavor symmetry. We explore the possible extension of this approach at the NLO level to strangeness $S = - 3$ and $S = - 4$ baryon-baryon systems where empirical information is rather scarce. Specifically we address the question how measurements of two-body correlation functions in heavy-ion collisions and/or in high-energetic proton-proton collisions can help to constrain the interaction in channels like $ΞΛ$ or $ΞΞ$ .
Comments:
10 pages, 3 figures, contribution to Chiral Dynamics 2021
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2201.08238 [pdf]
PoS(2024)·6 citations
04
[Submitted on 20 Jan 2022]
On the Stability of Superheavy Nuclei
Krzysztof Pomorski🇵🇱 · Artur Dobrowolski🇵🇱 · Bozena Nerlo-Pomorska🇵🇱 · Michal Warda🇵🇱 · Johann Bartel🇫🇷 · Zhigang Xiao🇨🇳 · Yongjing Chen🇨🇳 · Lile Liu🇨🇳 · Jun-Long Tian🇨🇳 · Xinyue Diao🇨🇳
Potential energy surfaces of even-even superheavy nuclei are evaluated within the macroscopic-microscopic approximation. A very rapidly converging analytical Fourier-type shape parametrization is used to describe nuclear shapes throughout the periodic table, including those of fissioning nuclei. The Lublin Strasbourg Drop and another effective liquid-drop type mass formula are used to determine the macroscopic part of nuclear energy. The Yukawa-folded single-particle potential, the Strutinsky shell-correction method, and the BCS approximation for including pairing correlations are used to obtain microscopic energy corrections. The evaluated nuclear binding energies, fission-barrier heights, and Q-alpha energies show a relatively good agreement with the experimental data. A simple one-dimensional WKB model a la Swiatecki is used to estimate spontaneous fission lifetimes, while alpha-decay probabilities are obtained within a Gamow-type model.
Comments:
13 pages, 19 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2201.08268 [pdf]
EPJA(2022)·17 citations
05
[Submitted on 20 Jan 2022]
Volume extrapolation via eigenvector continuation
Nuwan Yapa🇺🇸 · Sebastian König🇺🇸
We develop an extension of eigenvector continuation (EC) that makes it possible to extrapolate simulations of quantum systems in finite periodic boxes across large ranges of box sizes. The formal justification for this approach, which we call finite-volume eigenvector continuation (FVEC), is provided by matching periodic functions at different box sizes. As concrete FVEC implementation we use a discrete variable representation based on plane-wave states and present several applications calculated within this framework.
Comments:
7 pages, 4 figures, published version
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2201.08313 [pdf]
PRC(2022)·21 citations
06
[Submitted on 19 Jan 2022] (cross-list from hep-ph)
Analyzing N-point Energy Correlators Inside Jets with CMS Open Data
Patrick T. Komiske🇺🇸 · Ian Moult🇺🇸 · Jesse Thaler🇺🇸 · Hua Xing Zhu🇨🇳
Jets of hadrons produced at high-energy colliders provide experimental access to the dynamics of asymptotically free quarks and gluons and their confinement into hadrons. In this paper, we show that the high energies of the Large Hadron Collider (LHC), together with the exceptional resolution of its detectors, allow multipoint correlation functions of energy flow operators to be directly measured within jets for the first time. Using Open Data from the CMS experiment, we show that reformulating jet substructure in terms of these correlators provides new ways of probing the dynamics of QCD jets, which enables direct imaging of the confining transition to free hadrons as well as precision measurements of the scaling properties and interactions of quarks and gluons. This opens a new era in our understanding of jet substructure and illustrates the immense unexploited potential of high-quality LHC data sets for elucidating the dynamics of QCD.
Comments:
Includes music video of the confinement transition in real LHC data: https://www.youtube.com/watch?v=ZIFDcAXl73w. 5 pages, 4 figures + Supplemental Material. Code for Energy Correlators available at https://github.com/pkomiske/EnergyEnergyCorrelators v2. Updated references, modified color scheme and axis range for 2d plots, and updated video for ease of visualization. v3. Version to appear in PRL
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2201.07800 [pdf]
PRL(2023)·180 citations
07
[Submitted on 19 Jan 2022] (cross-list from hep-ph)
Parton distributions of light quarks and antiquarks in the proton
Lei Chang🇨🇳 · Fei Gao🇨🇳 · Craig D. Roberts🇨🇳
An algebraic Ansatz for the proton's Poincaré-covariant wave function, which includes both scalar and pseudovector diquark correlations, is used to calculate proton valence, sea, and glue distribution functions (DFs). Regarding contemporary data, a material pseudovector diquark component in the proton is necessary for an explanation of the neutron-proton structure function ratio; and a modest Pauli blocking effect in the gluon splitting function is sufficient to explain the proton's light-quark antimatter asymmetry. In comparison with pion DFs, the light-front momentum fractions carried by all identifiable parton classes are the same; on the other hand, the higher moments are different. Understanding these features may provide insights that explain distinctions between Nambu-Goldstone bosons and seemingly less complex hadrons.
Comments:
8 pages, 2 figures, 1 table
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:
2201.07870 [pdf]
PLB(2022)·38 citations
08
[Submitted on 20 Jan 2022] (cross-list from hep-ph)
Event-by-event investigation of the two-particle source function in heavy-ion collisions with EPOS
Dániel Kincses🇭🇺 · Maria Stefaniak🇩🇪 · Máté Csanád🇭🇺
Exploring the shape of the pair-source function for particles such as pions or kaons has been an important goal of heavy-ion physics, and substantial effort has been made in order to understand the underlying physics behind the experimental observations of non-Gaussian behavior. In experiments, since no direct measurement of the source function is possible, quantum-statistical momentum correlations are utilized to gain information about the space-time geometry of the particle emitting source. Event generators, such as EPOS, however, provide direct access to the freeze-out coordinates of final state particles, and thus the source function can be constructed and investigated. The EPOS model is a sophisticated hybrid model where the initial stage evolution of the system is governed by Parton-Based Gribov-Regge theory, and subsequently a hydrodynamic evolution is utilized, followed by hadronization and hadron dynamics. EPOS has already proven to be successful in describing several different experimental observations for systems characterized by baryon chemical potential close to zero, but so far the source shape has not been explored in detail. In this paper we discuss an event-by-event analysis of the two-particle source function in $s_{N N}$ = 200 GeV Au+Au collisions generated by the EPOS model. We find that when utilizing all stages of the model, Lévy-shaped distributions (unlike Gaussian distributions) provide a good description of the source shape in the individual events. Hence it is clear that it is not the event averaging that creates the non-Gaussian features in the pair distributions. Based on this observation, we determine Lévy-parameters of the source as a function of event centrality and particle momentum.
Comments:
13 pages, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2201.07962 [pdf]
Entropy(2022)·24 citations
09
[Submitted on 20 Jan 2022] (cross-list from cond-mat.mes-hall)
Chiral anomaly in non-relativistic systems: Berry curvature and chiral kinetic theory
Lan-Lan Gao🇨🇳 · Xu-Guang Huang🇨🇳
Chiral anomaly and the novel quantum phenomena it induces have been widely studied for Dirac and Weyl fermions. In most typical cases, the Lorentz covariance is assumed and thus the linear dispersion relations are maintained. However, in realistic materials, such as Dirac and Weyl semimetals, the non-linear dispersion relations appear naturally. We develop a kinetic framework to study the chiral anomaly for Weyl fermions with non-linear dispersions by using the methods of Wigner function and semi-classical equations of motion. In this framework, the chiral anomaly is sourced by Berry monopoles in momentum space and could be enhanced or suppressed due to the windings around the Berry monopoles. Our results can help understand the chiral anomaly-induced transport phenomena in non-relativistic systems.
Comments:
7 pages, no figure. Published in Chin. Phys. Lett
Subjects:
Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Strongly Correlated Electrons (cond-mat.str-el); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2201.07991 [pdf]
Chin.Phys.Lett.(2022)·9 citations
10
[Submitted on 20 Jan 2022] (cross-list from hep-ph)
Fluidity of the system produced in relativistic pp and heavy-ion collisions: Hadron resonance gas model approach
Ronald Scaria🇮🇳 · Dushmanta Sahu🇮🇳 · Captain R. Singh🇮🇳 · Raghunath Sahoo🇮🇳 · Jan-e Alam🇮🇳
We have estimated the dimensionless parameters such as Reynolds number ( $R e$ ), Knudsen number ( $K n$ ) and Mach number ( $M a$ ) for a multi-hadron system by using the excluded volume hadron resonance gas (EVHRG) model along with Hagedorn mass spectrum to include higher resonances in the system. The size dependence of these parameters indicate that the system formed in proton+proton collisions may achieve thermal equilibrium making it unsuitable as a benchmark to analyze the properties of the system produced in heavy ion collisions at similar energies. While the magnitude of $K n$ can be used to study the degree of thermalization and applicability of inviscid hydrodynamics, the variations of $R e$ and $M a$ with temperature ( $T$ ) and baryonic chemical potential ( $μ_{B}$ ) assist to understand the change in the nature of the flow in the system. Indeed the nature of flow changes from laminar to turbulent as $R e$ increases and the system is characterized as incompressible for low $M a (<< 1)$ and compressible for larger $M a$ . $M a$ can also be used to understand whether the flow is subsonic or supersonic.
Comments:
Same as the published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2201.08096 [pdf]
EPJA(2023)·9 citations
11
[Submitted on 20 Jan 2022] (cross-list from hep-ph)
Axions in Baryon Chiral Perturbation Theory
Thomas Vonk🇩🇪
I give an overview of recent developments in the study of the coupling of the QCD axion to nucleons and other octet baryons. I demonstrate how axions can be included into heavy baryon chiral perturbation theory, and present recent numerical results for the several axion-baryon couplings in SU(2) and SU(3) chiral perturbation theory for the Kim--Shifman--Vainstein--Zakharov (KSVZ) and the Dine--Fischler--Srednicki--Zhitnitsky (DFSZ) axion model.
Comments:
10 pages, 1 figure to be published in conference proceedings RDP online PhD school and workshop "Aspects of Symmetry'' (Regio2021), 8-12 November 2021
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2201.08132 [pdf]
PoS(2022)·0 citations
12
[Submitted on 20 Jan 2022] (cross-list from hep-ph)
Unified Explanation of the Anomalies in Semi-Leptonic $B$ decays and the $W$ Mass
Marcel Algueró🇪🇸 · Andreas Crivellin🇪🇸 · Claudio Andrea Manzari🇨🇭 · Joaquim Matias🇨🇭
The discrepancies between the measurements of rare (semi-)leptonic $B$ decays and the corresponding Standard Model predictions point convincingly towards the existence of new physics for which a heavy neutral gauge boson ( $Z^{'}$ ) is a prime candidate. However, the effect of the mixing of the $Z^{'}$ with the SM $Z$ , even though it cannot be avoided by any symmetry, is usually assumed to be small and thus neglected in phenomenological analyses. In this letter we point out that a mixing of the naturally expected size leads to lepton flavour universal contributions, providing a very good fit to $B$ data. Furthermore, the global electroweak fit is affected by $Z - Z^{'}$ mixing where the tension in the $W$ mass, recently confirmed and strengthened by the CDF measurement, prefers a non-zero value of it. We find that a $Z^{'}$ boson with a mass between $\approx 1 - 5 TeV$ can provide a unified explanations of the $B$ anomalies and the $W$ mass. This strongly suggests that the breaking of the new gauge symmetry giving raise to the $Z^{'}$ boson is linked to electroweak symmetry breaking with intriguing consequences for model building.
Comments:
11 pages, 3 figures, 3 tables; version published in PRD
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2201.08170 [pdf]
PRD(2022)·36 citations
13
[Submitted on 20 Jan 2022] (cross-list from nucl-ex)
Ground State Magnetic Dipole Moment of $^{40}$ Sc
Robert Powel · B. Alex Brown · Jason D. Holt · Andrew Klose · Kristian König · Jeremy Lantis · Kei Minamisono · Takayuki Miyagi · Skyy Pineda
The hyperfine coupling constants of the proton dripline odd-odd $^{40}$ Sc nucleus were deduced from the hyperfine spectrum of the $3 d 4 s^{3} D_{2}$ \, $\leftrightarrow$ \, $3 d 4 p^{3} F_{3}^{\circ}$ transition in Sc II, measured by the bunched beam collinear laser spectroscopy technique. The ground state magnetic dipole and electric quadrupole moments were determined for the first time as $μ$ \,=\, $+ 5.57 (4) (2) μ_{N}$ and $Q$ \,=\, $+ 42 (38) (28) e^{2} f m^{2}$ , respectively. The magnetic moment is well reproduced by the additivity rule with magnetic moments of neighboring odd-even nuclei in the vicinity of the doubly-magic $^{40}$ Ca nucleus. An ab-initio multishell valence-space Hamiltonian was also employed to calculate the magnetic moment of $^{40}$ Sc, which spans across the $s d$ and $f p$ nuclear shells, where we obtained good agreements.
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2201.08332 [pdf]
PRC(2022)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE