Nuclear Theory·nucl-th

Monday·May 10, 2021

15 papers—5 primary·10 cross-listed

06
[Submitted on 6 May 2021] (cross-list from quant-ph)
A digital quantum simulation of the Agassi model
Pedro Pérez-Fernández🇪🇸 · José Miguel Arias🇪🇸 · José Enrique García-Ramos🇪🇸 · Lucas Lamata🇪🇸
A digital quantum simulation of the Agassi model from nuclear physics is proposed and analyzed. The proposal is worked out for the case with four different sites. Numerical simulations and analytical estimations are presented to illustrate the feasibility of this proposal with current technology. The proposed approach is fully scalable to a larger number of sites. The use of a quantum correlation function as a probe to explore the quantum phases by quantum simulating the time dynamics, with no need of computing the ground state, is also studied. Evidence is given showing that the amplitude of the time dynamics of a correlation function in this quantum simulation is linked to the different quantum phases of the system. This approach establishes an avenue for the digital quantum simulation of useful models in nuclear physics.
Comments:
8 pages, 5 figures. Improved manuscript. Published in PLB
Subjects:
Quantum Physics (quant-ph); Nuclear Theory (nucl-th)
arXiv:
2105.02834 [pdf]
PLB(2022)·20 citations
07
[Submitted on 6 May 2021] (cross-list from physics.comp-ph)
On the numerical evaluation of real-time path integrals: Double exponential integration and the Maslov correction
R. Rosenfelder🇨🇭
Ooura's double exponential integration formula for Fourier transforms is applied to the oscillatory integrals occuring in the path-integral description of real-time Quantum Mechanics. Due to an inherent, implicit regularization multi-dimensional Gauss-Fresnel integrals are obtained numerically with high precision but modest number of function calls. In addition, the Maslov correction for the harmonic oscillator is evaluated numerically with an increasing number of time slices in the path integral thereby clearly demonstrating that the real-time propagator acquires an additional phase $- π /2$ each time the particle passes through a focal point. However, in the vicinity of these singularities an overall small damping factor is required. Prospects of evaluating scattering amplitudes of finite-range potentials by direct numerical evaluation of a real-time path integral are discussed.
Comments:
21 pages, 7 figures, 2 tables, LATEX with amsmath,amssymb
Subjects:
Computational Physics (physics.comp-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2105.02880 [pdf]
0 citations
08
[Submitted on 6 May 2021] (cross-list from astro-ph.HE)
Impact of PREX-II and combined Radio/NICER/XMM-Newton's mass-radius measurement of PSRJ0740+6620 on the dense matter equation of state
Bhaskar Biswas🇮🇳
In this paper, we discuss the impact of the following laboratory experiments and astrophysical observation of neutron stars (NSs) on its equation of state (EoS): (a) The new measurement of neutron skin thickness of $^{208} Pb$ , $R_{skin}^{208} = 0.29 \pm 0.07$ fm by the PREX-II experiment. (b) The mass measurement of PSR J0740+6620 has been slightly revised down by including additional $\sim 1.5$ years of pulsar timing data. As well as the radius measurement of PSR J0740+6620 by joint NICER/XMM-Newton collaboration which has a similar size to PSR J0030+0451. We combine these information using Bayesian statistics along with the previous LIGO/Virgo and NICER observations of NS using a hybrid nuclear+piecewise polytrope (PP) EoS parameterization. Our findings are as follows: (a). Adding PREX-II result yields the value of empirical parameter $L = 6 9_{- 19}^{+ 21}$ MeV, $R_{skin}^{208} = 0.2 0_{- 0.05}^{+ 0.05}$ fm, and radius of a $1.4 M_{⊙}$ ( $R_{1.4}) = 12.7 5_{- 0.54}^{+ 0.42}$ km at $1 σ$ confidence interval (CI). We find these inferred values are mostly dominated by the combined astrophysical observations as the measurement uncertainty in $R_{skin}^{208}$ by PREX-II is much broader. Also, a better measurement of $R_{skin}^{208}$ might have a little effect on the radius of low mass NSs, but for the high masses there will be almost no effect. (b) After adding The revised mass and radius measurement of PSR J0740+6620, we find the inferred radius of NSs is slightly pushed towards the larger values and the uncertainty on the radius of a $2.08 M_{⊙}$ NS is moderately improved.
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2105.02886 [pdf]
ApJ(2021)·95 citations
09
[Submitted on 6 May 2021] (cross-list from hep-ph)
Mass spectra and transition magnetic moments of low lying charmed baryons in a quark model
Zahra Ghalenovi🇮🇷 · Masoumeh Moazzen Sorkhi🇮🇷
Excited state mass spectra of the low lying single charmed baryons with non strangeness have been calculated in a hypercentral approach. The six-dimensional hyperradial Schrödinger equation is solved by applying a simple variational method. We extend our scheme to predict the magnetic moments and the $\frac{3}{2}^{+} \to \frac{1}{2}^{+}$ transition magnetic moments of $Σ_{c}$ and $Λ_{c}$ state baryons. A comparison of our results with the experimental data and predictions obtained in recent models is also presented.
Comments:
arXiv admin note: text overlap with arXiv:1707.01319
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2105.02928 [pdf]
IJMPE(2021)·2 citations
10
[Submitted on 7 May 2021] (cross-list from hep-ph)
Partial wave analysis of $K^{+} N$ scattering and the possibility of pentaquark $Θ^{+} (1540)$
Kook-Jin Kong🇰🇷 · Byung-Geel Yu🇰🇷
Elastic $K^{+} n \to K^{+} n$ and charge exchange $K^{+} n \to K^{0} p$ reactions at low momenta are investigated using the partial wave analysis. Isospin relation gives constrains for the partial $s$ - and $p$ -waves among elastic $K^{+} p$ , $K^{+} n$ and charge exchange $K^{+} n \to K^{0} p$ amplitudes. Two sets of the phase shift for these partial waves in the isoscalar channel are obtained from the fit of experimental data on total and differential cross sections. Polarization observable leads to a good criterion to decide which set is valid. Differential cross section data near $P_{Lab} = 434$ MeV/ $c$ suggests a possibility of a resonance, e.g., the exotic $Θ^{+} (1540)$ baryon around $s ≃$ 1.54GeV.
Comments:
6 pages, 9 figures, 1 table, Proc. APFB 2020 Conf
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2105.03040 [pdf]
Few Body Syst.(2021)·2 citations
11
[Submitted on 7 May 2021] (cross-list from hep-ph)
Scalar Mesons and Axial-vector Mesons Via Dyson-Schwinger Equation and Bethe-Salpeter Equation Approach
Muyang Chen🇨🇳
In this work, I studied the spectrum of scalar mesons and axial-vector mesons via Dyson-Schwinger equation and Bethe-Salpeter equation approach in the rainbow-ladder approximation. An interaction model with a repulsive term added to the one used for the pseudoscalar and vector mesons is proposed. My results are consistent with the experiment data and other model results, which shows that this interaction model is effective for all the heavy, heavy-light, and light scalar and axial-vector mesons.
Comments:
5 pages, 1 figure
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2105.03063 [pdf]
1 citation
12
[Submitted on 7 May 2021] (cross-list from hep-ph)
Isospin asymmetry in holographic baryonic matter
Nicolas Kovensky🇬🇧 · Andreas Schmitt🇬🇧
We study baryonic matter with isospin asymmetry, including fully dynamically its interplay with pion condensation. To this end, we employ the holographic Witten-Sakai-Sugimoto model and the so-called homogeneous ansatz for the gauge fields in the bulk to describe baryonic matter. Within the confined geometry and restricting ourselves to the chiral limit, we map out the phase structure in the presence of baryon and isospin chemical potentials, showing that for sufficiently large chemical potentials condensed pions and isospin-asymmetric baryonic matter coexist. We also present first results of the same approach in the deconfined geometry and demonstrate that this case, albeit technically more involved, is better suited for comparisons with and predictions for real-world QCD. Our study lays the ground for future improved holographic studies aiming towards a realistic description of charge neutral, beta-equilibrated matter in compact stars, and also for more refined comparisons with lattice studies at nonzero isospin chemical potential.
Comments:
53 pages, 8 figures, v2: minor improvements in the text, format adapted to SciPost Physics; v3: typos in Eqs.(20) and (30c) corrected
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2105.03218 [pdf]
SciPost Phys.(2021)·35 citations
13
[Submitted on 7 May 2021] (cross-list from hep-ph)
Dalitz plot studies of $D^{0} \to K_{S}^{0} K^{+} K^{-}$ decays in a factorization approach
J.-P.Dedonder🇫🇷 · R. Kamiński🇵🇱 · L. Leśniak🇵🇱 · B. Loiseau🇫🇷
The $BABAR$ Collaboration data of the $D^{0} \to K_{S}^{0} K^{+} K^{-}$ process are analyzed within a quasi two-body factorization framework. In earlier studies, assuming $D^{0}$ transitions to two kaons and the transitions between one kaon and two kaons to proceed through the dominant intermediate resonances, we approximated them as being proportional to the kaon form factors. To obtain good fits, one has to multiply the scalar-kaon form factors, derived from unitary relativistic coupled-channel models or in a dispersion relation approach, by phenomenological energy-dependent functions. The final state kaon-kaon interactions in the $S$ -, $P$ - and $D$ - waves are taken into account. All $S$ -wave channels are treated in a unitary way. The $K^{+} K^{-}$ and $K ˉ^{0} K^{+}$ $S$ -wave effective mass squared distributions, corrected for phase space, are shown, in a model-independent manner, to be significantly different. Then the $f_{0} (980)$ resonance must be included at variance with the BABAR analysis. The best fit has 19 free parameters and indicates i) the dominance of annihilation amplitudes, ii) a large dominance of the $f_{0} (980)$ meson in the near threshold $K^{+} K^{-}$ invariant mass distribution and iii) a sizable branching fraction to the $K_{S}^{0} [ρ (770)^{+} + ρ (1450)^{+} + ρ (1700)^{+}]$ final states. An appendix provides an update of the determination of the isoscalar-scalar meson-meson amplitudes based on an enlarged set of data. A second appendix proposes two alternative fits based on scalar-kaon form factors calculated from the Muskhelishvili-Omnès dispersion relation approach. These fits have $χ^{2}$ quite close to that of the best fit but they show important contributions from both the $f_{0}$ and $a_{0}^{0}$ mesons and a weaker role of the $ρ^{+}$ mesons.
Comments:
50 pages, 17 figures; v2: figure 10 is now cited in the text, typos corrected, matches the published (PRD) version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2105.03355 [pdf]
PRD(2021)·14 citations
14
[Submitted on 7 May 2021] (cross-list from astro-ph.SR)
Effects of Magnetic Fields in Hot White Dwarfs
J. Peterson🇺🇸 · V. Dexheimer🇺🇸 · R. Negreiros🇧🇷 · B. G. Castanheira🇺🇸
In this work, we study the effects of temperature on magnetic white dwarfs. We model their interior as a nuclei lattice surrounded by a relativistic free Fermi gas of electrons, accounting for effects from temperature, Landau levels and anomalous magnetic moment. We find that, at low densities (corresponding to the outer regions of star), both temperature and magnetic field effects play an important role in the calculation of microscopic thermodynamical quantities. To study macroscopic stellar structures within a general-relativistic approach, we solve numerically the coupled Einstein's-Maxwell's equations for fixed entropy per particle configurations and discuss how temperature affects stellar magnetic field profiles, masses and radii.
Subjects:
Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2105.03387 [pdf]
ApJ(2021)·17 citations
15
[Submitted on 7 May 2021] (cross-list from hep-ph)
Vector-like Leptons in Light of the Cabibbo-Angle Anomaly
Claudio Andrea Manzari🇨🇭
The first row of the Cabibbo-Cobayashi-Maskawa (CKM) matrix shows a discrepancy of $\sim$ $3 σ$ with unitarity, known as the "Cabibbo Angle Anomaly" (CAA). This tension can be explained via modified $W$ couplings to leptons, but in order to consistently assess the validity of this solution, a global fit including the electroweak (EW) precision constraints and the low energy tests of lepton flavour universality (LFU) is necessary. Performing such a fit for gauge-invariant dimension-6 operators, we find that even when assuming LFU, including the CKM elements $V_{u s}$ and $V_{u d}$ into the electroweak fit has a relevant impact, shifting the best fit point significantly. Vector-like leptons (VLLs) are prime candidates for a corresponding UV completion since they can affect the $W$ and $Z$ couplings to leptons already at tree-level. Studying each pattern of new physics (NP) given by the six possible representations of VLLs (under the SM gauge group) we find that any single representation describes experimental data at most slighlty better than the SM hypothesis. However, allowing for several representations of VLLs at the same time, we find a simple scenario consisting of a singlet, $N$ , coupling to electrons and a triplet, $Σ_{1}$ , coupling to muons which not only explains the CAA but also improves the electroweak fit in such a way that its best fit point is preferred by more than $4 σ$ with respect to the SM.
Comments:
7 pages, 1 figure, 2 tables, contribution to BSM-2021 and the 2021 EW & QCD sessions of the 55th Rencontres de Moriond (shorter version)
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2105.03399 [pdf]
7 citations

Affiliations

first authorsco-authorsvia INSPIRE