Nuclear Theory·nucl-th

Thursday·August 1, 2024

11 papers—5 primary·6 cross-listed

01
[Submitted on 30 Jul 2024]
Determination of electron screening potential of 6 Li(p,{\alpha})3 He reaction using MultiLayer Perceptron based neural network
D. Chattopadhyay
Background: Understanding the nuclear reactions between light charged nuclei at sub-coulomb energy region holds significant importance in several astrophysical processes. Determination of the precise reaction cross-section within the astrophysically important Gamow range is difficult because of electron screening. Various polynomial fits, R-Matrix and Indirect Trojan horse method estimate much higher electron screening energies as compared to the adiabatic limit. Purpose: Obtain the bare astrophysical S-factor of 6 Li(p,{\alpha})3 He using Multi-Layer Perceptron based Artificial Neural Network based analysis and extract the electron screening energies. Methods: Experimental S-factor of 6 Li(p,{\alpha})3 He, available in literature, are reanalyzed using the Multi-LayerPerceptron based Artificial Neural Network based algorithm to obtain the energy dependent astrophysical S-factor. Bare astrophysical S-factor is also calculated using the same Feed-forward Artificial Neural Network from the data range above 60 keV where the electron screening effect is expected to be negligible. Electron screening potential is then obtained by taking the ratio of total shielded S-factor with the bare S-factor. Results and Conclusions: The electron screening potential obtained from the Present work through the Artificial Neural network based algorithm is found to be 220 eV. The extracted electron screening potential through the present analysis indicates that the Artificial Neural Network might be an alternative tools for estimation the electron screening potential involving light nuclei.
Comments:
arXiv admin note: substantial text overlap with arXiv:2407.20049
Subjects:
Nuclear Theory (nucl-th); Instrumentation and Methods for Astrophysics (astro-ph.IM)
arXiv:
2407.21089 [pdf]
Nucl.Instrum.Meth.B(2024)·2 citations
02
[Submitted on 30 Jul 2024]
Investigating the crust of neutron stars with neural-network quantum states
Bryce Fore · Jane Kim · Morten Hjorth-Jensen · Alessandro Lovato
An accurate description of low-density nuclear matter is crucial for explaining the physics of neutron star crusts. In the density range between approximately 0.01 fm $^{- 3}$ and 0.1 fm $^{- 3}$ , matter transitions from neutron-rich nuclei to various higher-density pasta shapes, before ultimately reaching a uniform liquid. In this work, we introduce a variational Monte Carlo method based on a neural Pfaffian-Jastrow quantum state, which allows us to model the transition from the liquid phase to neutron-rich nuclei microscopically. At low densities, nuclear clusters dynamically emerge from the microscopic interactions among protons and neutrons, which we model based on pionless effective field theory. Our variational Monte Carlo approach represents a significant improvement over the state-of-the-art auxiliary-field diffusion Monte Carlo method, which is severely hindered by the fermion-sign problem in this low-density regime and cannot capture the onset of clusters. In addition to computing the energy per particle of symmetric nuclear matter and pure neutron matter, we analyze an intermediate isospin-asymmetry configuration to elucidate the formation of nuclear clusters. We also provide evidence that the presence of such nuclear clusters influences the amount of protons in the crust compared to protons in beta-equilibrated, neutrino-transparent matter.
Comments:
10 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
2407.21207 [pdf]
Commun.Phys.(2025)·16 citations
03
[Submitted on 31 Jul 2024]
Considerations on measuring spin-spin correlation of hyeprons in heavy-ion experiments
Diyu Shen🇨🇳 · Jinhui Chen🇨🇳 · Aihong Tang🇺🇸
The significant global spin alignment observed for $ϕ$ mesons in heavy-ion collisions has sparked intense discussions about its origin and implications. One explanation suggests that fluctuations in the strong force field may introduce strong spin correlations between strange ( $s$ ) and anti-strange ( $s ˉ$ ) quarks, leading to the global spin alignment of $ϕ$ mesons. Extending this line of research, the theoretical community has proposed studying the spin correlation between $Λ$ and $Λ ˉ$ hyperons. In this paper, we construct experimental observables and make connections between them and the theoretical proposed quantities.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex)
arXiv:
2407.21291 [pdf]
7 citations
04
[Submitted on 31 Jul 2024]
Neutrino and antineutrino charged-current multi-nucleon cross sections revisited
J. E. Sobczyk🇩🇪 · J. Nieves🇪🇸
In this work we improve on several aspects of the computation of the (anti-)neutrino charged-current multi-nucleon cross section carried out in Phys.Rev.C 83 (2011) 045501 and Phys.Rev.C 102 (2020) 024601. Most importantly, we implement a consistent treatment of the nucleon self-energy in the $W^{\pm} N \to N^{'} π$ amplitude entering the definition of the two-particle two-hole (2p2h) cross-section, and estimate the source of uncertainty of our model due to a simplified treatment of the $Δ$ self-energy. Our new predictions are around $20 - 40%$ higher than previously. We show comparisons for the inclusive lepton double-differential cross sections, with no pions in the final state, measured by MiniBooNE on carbon and by T2K on carbon and oxygen. In all cases, we find an excellent reproduction of the experiments, and in particular, the neutrino MiniBooNE data is now well described without requiring a global $90%$ re-scaling of the flux. In addition, we take the opportunity of this revision to discuss in detail several important issues of the calculation of the 2p2h cross section, delving into the microscopic dynamics of the multi-nucleon mechanisms. The improved treatment presented in this work provides realistic first-step emitted two-nucleon final state momentum configurations, beyond the approximation of phase-space distributions.
Comments:
16 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2407.21587 [pdf]
PRC(2025)·11 citations
05
[Submitted on 31 Jul 2024]
Weak rates in strongly coupled cold quark matter
Carlos Hoyos🇪🇸 · Andrea Olzi🇮🇹 · David Rodriguez-Fernandez🇪🇸
The rates of flavor-changing weak processes are crucial in determining the conditions of beta equilibrium in neutron stars and mergers, influencing the damping of oscillations, the stability of rotating pulsars, and the emission of gravitational waves. We derive a formula for these rates at nonzero temperature, to leading order in the Fermi coupling and exact in the QCD coupling. Utilizing a simple phenomenological holographic model dual to QCD, we study massless unpaired quark matter at high densities. We numerically compute the rate for small deviations from beta equilibrium and derive an analytic approximation for small temperatures. Our findings reveal that, compared to the perturbative result, the rate is suppressed by logarithmic factors of the temperature.
Comments:
20 pages+appendices, 5 figures, minor corrections
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
arXiv:
2407.21643 [pdf]
JHEP(2024)·6 citations
06
[Submitted on 30 Jul 2024] (cross-list from hep-ph)
The Fox-Wolfram Moment of Jet Production in Relativistic Heavy Ion Collisions
Wei-Xi Kong🇨🇳 · Ben-Wei Zhang🇨🇳
We present the first theoretical investigation of Fox-Wolfram moments (FWMs) for multi-jet production in relativistic heavy ion collisions. In this work, jet productions in p+p collisions are computed with a Monte Carlo event generator SHERPA, while the Linear Boltzmann Transport model is utilized to simulate the multiple scattering of energetic partons in the hot and dense QCD matter. The event-normalized distributions of the lower-order FWM, $H_{1}^{T}$ in p+p and Pb+Pb collisions are calculated. It is found that for events with jet number $n_{jet} = 2$ the $H_{1}^{T}$ distribution in Pb+Pb is suppressed at small $H_{1}^{T}$ while enhanced at large $H_{1}^{T}$ region as compared to p+p. For events with $n_{jet} > 2$ , the jet number reduction effect due to jet quenching in the QGP decreases the $H_{1}^{T}$ distribution at large $H_{1}^{T}$ in Pb+Pb relative to p+p. The medium modification of the Fox-Wolfram moment $H_{1}^{T}$ for events with $n_{jet} \geq 2$ are also presented, which resemble those of events with $n_{jet} = 2$ . Its reason is revealed through the relative contribution fractions of events with different final-state jet numbers to $H_{1}^{T}$ .
Comments:
10 pages, 7 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2407.20680 [pdf]
CPC(2025)·1 citation
07
[Submitted on 30 Jul 2024] (cross-list from hep-ph)
Gravitational form factors of pion from top-down holographic QCD
Daisuke Fujii🇯🇵 · Akihiro Iwanaka🇯🇵 · Mitsuru Tanaka🇯🇵
The gravitational form factors (GFFs) of pions are calculated from a top-down holographic quantum chromodynamics (QCD) approach with momentum transfer dependence for the first time. It is important because the GFFs of hadrons have information on the internal stress distribution that may provide insight into the mechanism of how QCD forms hadrons. The forward limit value of this GFFs, i.e. the D-term, was also obtained. Furthermore, in this approach, we observe the so-called glueball dominance, in which pions have gravitational interactions via infinite glueball spectra.
Comments:
8 pages, 1 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2407.21113 [pdf]
PRD(2024)·27 citations
08
[Submitted on 30 Jul 2024] (cross-list from quant-ph)
A framework for semi-universality: Semi-universality of 3-qudit SU(d)-invariant gates
Austin Hulse🇺🇸 · Hanqing Liu🇺🇸 · Iman Marvian🇺🇸
Quantum circuits with symmetry-respecting gates have attracted broad interest in quantum information science. While recent work has developed a theory for circuits with Abelian symmetries, revealing important distinctions between Abelian and non-Abelian cases, a comprehensive framework for non-Abelian symmetries has been lacking. In this work, we develop novel techniques and a powerful framework that is particularly useful for understanding circuits with non-Abelian symmetries. Using this framework we settle an open question on quantum circuits with SU(d) symmetry. We show that 3-qudit SU(d)-invariant gates are semi-universal, i.e., generate all SU(d)-invariant unitaries, up to certain constraints on the relative phases between sectors with inequivalent representation of symmetry. Furthermore, we prove that these gates achieve full universality when supplemented with 3 ancilla qudits. Interestingly, we find that studying circuits with 3-qudit gates is also useful for a better understanding of circuits with 2-qudit gates. In particular, we establish that even though 2-qudit SU(d)-invariant gates are not themselves semi-universal, they become universal with at most 11 ancilla qudits. Additionally, we investigate the statistical properties of circuits composed of random SU(d)-invariant gates. Our findings reveal that while circuits with 2-qudit gates do not form a 2-design for the Haar measure over SU(d)-invariant unitaries, circuits with 3-qudit gates generate a t-design, with t that is quadratic in the number of qudits.
Comments:
Preliminary version; 21 pages + 24 pages of Supplementary Material; 5 Figures, Comments Welcome!
Subjects:
Quantum Physics (quant-ph); High Energy Physics — Theory (hep-th); Mathematical Physics (math-ph); math.MP (math.MP); Nuclear Theory (nucl-th)
arXiv:
2407.21249 [pdf]
11 citations
09
[Submitted on 31 Jul 2024] (cross-list from hep-ph)
Electromagnetic $∣ G_{E} / G_{M} ∣$ ratios of hyperons at large timelike $q^{2}$
G. Ramalho🇰🇷 · M.T. Peña🇵🇹 · K. Tsushima🇧🇷 · Myung-Ki Cheoun🇰🇷
In recent years, it has become possible to measure not only the magnitude of the electric ( $G_{E}$ ) and magnetic ( $G_{M}$ ) form factors of spin $\frac{1}{2}$ baryons, but also to measure the relative phases of those quantities in the timelike kinematic region. Aiming to interpret present $∣ G_{E} / G_{M} ∣$ data on hyperons of the baryon octet, as well as to predict future data, we present model calculations of that ratio for large invariant 4-momentum square $q^{2}$ in the timelike region ( $q^{2} > 0$ ). Without any further parameter fitting,we extend to the timelike region a covariant quark model previously developed to describe the kinematic spacelike region ( $q^{2} \leq 0$ ) of the baryon octet form factors. The model takes into account both the effects of valence quarks and the excitations of the meson cloud which dresses the baryons. This application to the timelike region assumes an approximation based on unitarity and analyticity that is valid only in the large $q^{2}$ region. Using the recent data from BESIII we establish the regime of validity of this approximation. We report here that our results for the effective form factor (combination of $∣ G_{E} ∣$ and $∣ G_{M} ∣$ ) are in good agreement with the data already for $q^{2}$ values above 15 GeV $^{2}$ . In addition, a more conservative onset of the validity of the approximation is provided by the newly available $∣ G_{E} / G_{M} ∣$ data which suggest that our predictions may be compared against data for $q^{2} \geq$ 20 GeV $^{2}$ . This is expected in the near future, when the range of the present measurements is expanded to the 20--50 GeV $^{2}$ region.
Comments:
Version accepted for publication at Phys. Lett. B. 11 pages, 5 figures + supplementary material
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:
2407.21397 [pdf]
PLB(2024)·14 citations
10
[Submitted on 31 Jul 2024] (cross-list from hep-ph)
Real-time chiral dynamics at finite temperature from quantum simulation
Kazuki Ikeda🇺🇸 · Zhong-Bo Kang🇺🇸 · Dmitri E. Kharzeev🇺🇸 · Wenyang Qian🇪🇸 · Fanyi Zhao🇺🇸
In this study, we explore the real-time dynamics of the chiral magnetic effect (CME) at a finite temperature in the (1+1)-dimensional QED, the massive Schwinger model. By introducing a chiral chemical potential $μ_{5}$ through a quench process, we drive the system out of equilibrium and analyze the induced vector currents and their evolution over time. The Hamiltonian is modified to include the time-dependent chiral chemical potential, thus allowing the investigation of the CME within a quantum computing framework. We employ the quantum imaginary time evolution (QITE) algorithm to study the thermal states, and utilize the Suzuki-Trotter decomposition for the real-time evolution. This study provides insights into the quantum simulation capabilities for modeling the CME and offers a pathway for studying chiral dynamics in low-dimensional quantum field theories.
Comments:
16 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2407.21496 [pdf]
JHEP(2024)·20 citations
11
[Submitted on 31 Jul 2024] (cross-list from hep-ph)
Simple high-accuracy method for solving bound-state equations with the Cornell potential in momentum space
Alfred Stadler🇵🇹 · Elmar P. Biernat🇵🇹 · Vasco Valverde🇵🇹
The well-known Cornell quark-antiquark potential in momentum space contains singularities both in its one-gluon-exchange (OGE) and linear confining parts, which prevents a direct use of the convenient Nyström method to solve the corresponding bound-state integral equation for the meson masses. While it has been known for a long time how the Coulomb-type singularity in the OGE potential can be treated with a subtraction technique, only very complicated methods have been developed to deal with the stronger singularity in the linear potential. In this work, we present a simple subtraction method to remove this singularity from the kernel, such that the Nyström method becomes applicable. Derivatives of the wave function, that appear as a result of the subtraction, are represented by means of interpolating functions, for which we found Lagrange polynomials to be very efficient. Test calculations show excellent agreement with exactly known energy eigenvalues. By increasing the number of integration points and the order of the Lagrange interpolation polynomials, extremely high accuracy can be achieved. This method can also be extended to relativistic Bethe-Salpeter type equations with singular kernels.
Comments:
14 pages; affiliations updated; 2 new paragraphs and the new Table VII added in Sec. IV; data availability Ref. [40] added; version published in Physical Review D
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2407.21789 [pdf]
PRD(2024)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE