Nuclear Theory·nucl-th

Wednesday·April 20, 2022

11 papers—5 primary·6 cross-listed

01
[Submitted on 19 Apr 2022]
Averaged transverse momentum correlations of hadrons in relativistic heavy-ion collisions
Yan-ting Feng🇨🇳 · Feng-lan Shao🇨🇳 · Jun Song🇨🇳
We compile experimental data for the averaged transverse momentum ( $⟨ p_{T} ⟩$ ) of proton, $Λ$ , $Ξ^{-}$ , $Ω^{-}$ and $ϕ$ at mid-rapidity in Au+Au collisions at $s_{N N} =$ 200, 39, 27, 19.6, 11.5, 7.7 GeV and in Pb+Pb collisions at $s_{N N} =$ 2.76 TeV, and find that experimental data of these hadrons exhibit systematic correlations. We apply a quark combination model with equal-velocity combination approximation to derive analytic formulas of hadronic $⟨ p_{T} ⟩$ in the case of exponential form of quark $p_{T}$ spectra at hadronization. We use them to successfully explain the systematic correlations exhibited in $⟨ p_{T} ⟩$ data of $p Λ$ , $Λ Ξ^{-}$ , $Ξ^{-} Ω^{-}$ and $Ξ^{-} ϕ$ pairs. We also use them to successfully explain the regularity observed in $⟨ p_{T} ⟩$ of these hadrons as the function of $(d N_{c h} / d y) / (N_{p a r t} /2)$ at mid-rapidity in central heavy-ion collisions at both RHIC and LHC energies. Our results suggest that the constituent quark degrees of freedom and the equal-velocity combination of these constituent quarks at hadronization play important role in understanding the production of baryons and $ϕ$ meson at these RHIC and LHC energies.
Comments:
10 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2204.08641 [pdf]
PRC(2022)·6 citations
02
[Submitted on 19 Apr 2022]
Symplectic Effective Field Theory for Nuclear Structure Studies
D. Kekejian🇺🇸 · J. P. Draayer🇺🇸 · V. I. Mokeev🇺🇸 · C. D. Roberts🇨🇳
A Symplectic Effective Field Theory that unveils the observed emergence of symplectic symmetry in atomic nuclei is advanced. Specifically, starting from a simple extension of the harmonic-oscillator Lagrangian, an effective field theory applied against symplectic basis states is shown to yield a Hamiltonian system with one fitted parameter. The scale of the system can be determined self consistently as the ratio of the average volume of a nucleus assumed to be spherical to its volume as determined by the average number of oscillator quanta, which is stretched by the fact that the plane-wave solution satisfies the equations of motion at every order without the need for perturbative corrections. As an application of the theory, results for 20Ne, 22Ne and 22Mg are presented that yield energy spectra, B(E2) values, and matter radii in good agreement with experimentally measured results.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2204.08642 [pdf]
PRC(2022)·1 citation
03
[Submitted on 19 Apr 2022]
Enhanced proton-boron nuclear fusion cross sections in intense high-frequency laser
Wenjuan Lv · Hao Duan · Jie Liu
We investigate the proton-boron nuclear fusion cross sections under the influence of the intense linearly polarized monochromatic laser fields with high frequency. First, we rewrite the time-dependent Schrödinger equation using Kramers-Henneberger (KH) transformation which allows for shifting all time dependence of the problem into the potential function. Then, for the intense laser fields that satisfy the high frequency limit, the time-averaged scheme in the KH framework should be valid. We can use WKB approximation to evaluate Coulomb barrier penetrability and then calculate proton-boron nuclear fusion cross sections by a phenomenological Gamow form. We show that the corresponding Coulomb barrier penetrability increases significantly due to the depression of the time-averaged potential barrier. As a result, we find that proton-boron nuclear fusion cross sections can be enhanced effectively depending on a dimensionless quantity $n_{d}$ , which equals the ratio of the quiver oscillation amplitude to the geometrical touching radius of the proton and boron nucleus. For $n_{d} = 9$ , we predict that the resonance peak of the fusion cross-section is enhanced by about $26$ times at the incident energy of $ε = 148$ keV. And for another incident energy of $ε = 586$ keV, the resonance peak of fusion cross-section is not only enhanced but also shifted to lower energy of $ε = 392$ keV due to the mechanism of over-barrier fusion.
Comments:
arXiv admin note: text overlap with arXiv:2107.03085
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2204.08667 [pdf]
NPA(2022)·5 citations
04
[Submitted on 19 Apr 2022]
Finite amplitude method on the deformed relativistic Hartree-Bogoliubov theory in continuum: The isoscalar giant monopole resonance in exotic nuclei
Xuwei Sun · Jie Meng
Finite amplitude method based on the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc-FAM) is developed and applied to study isoscalar giant monopole resonance in exotic nuclei. Validation of the numerical implementation is examined for $^{208} Pb$ . The isoscalar giant monopole resonances for even-even calcium isotopes from $^{40} Ca$ to the last bound neutron-rich nucleus $^{80} Ca$ are calculated, and a good agreement with the available experimental centroid energies is obtained for $^{40 - 48} Ca$ . For the exotic calcium isotopes, e.g., $^{68} Ca$ and $^{80} Ca$ , the DRHBc-FAM calculated results are closer to the energy weighted sum rule than the calculations on the harmonic oscillator basis, which highlights the advantages of DRHBc-FAM in describing giant resonances for exotic nuclei. In order to explore the soft monopole mode in the exotic nuclei, the giant monopole resonance for the deformed exotic nucleus $^{200} Nd$ is investigated, where the prolate shape and the oblate shape coexist. A soft monopole mode near 6.0 MeV is found in the prolate case, and another one near 4.5 MeV is found in the oblate case. The transition density of the soft monopole mode shows in phase or out-of-phase vibrations near the surface region, which is generated by quadrupole vibrations.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2204.08677 [pdf]
PRC(2022)·21 citations
05
[Submitted on 19 Apr 2022]
Neutron star radii, deformabilities, and moments of inertia from experimental and ab initio theory constraints on the 208Pb neutron skin thickness
Yeunhwan Lim🇰🇷 · Jeremy W. Holt🇺🇸
Recent experimental and ab initio theory investigations of the 208Pb neutron skin thickness are sufficiently precise to inform the neutron star equation of state. In particular, the strong correlation between the 208Pb neutron skin thickness and the pressure of neutron matter at normal nuclear densities leads to modified predictions for the radii, tidal deformabilities, and moments of inertia of typical 1.4 solar-mass neutron stars. In the present work, we study the relative impact of these recent analyses of the 208Pb neutron skin thickness on bulk properties of neutron stars within a Bayesian statistical analysis. Two models for the equation of state prior are employed in order to study the role of the highly uncertain high-density equation of state. From our combined Bayesian analysis of nuclear theory, nuclear experiment, and observational constraints on the dense matter equation of state, we find at the 90% credibility level $R_{1.4} = 12.3 6_{- 0.73}^{+ 0.38}$ km for the radius of a 1.4 solar-mass neutron star, $R_{2.0} = 11.9 6_{- 0.71}^{+ 0.94}$ km for the radius of a 2.0 solar-mass neutron star, $Λ_{1.4} = 44 0_{- 144}^{+ 103}$ for the tidal deformability of a 1.4 solar-mass neutron star, and $I_{1.338} = 1.42 5_{- 0.146}^{+ 0.074} \times 1 0^{45} g cm^{2}$ for the moment of inertia of PSR J0737-3039A whose mass is 1.338 solar masses.
Comments:
13 pages, 6 figures. Submitted to Galaxies special issue "Neutron Stars and Hadrons in the Era of Gravitational Wave Astrophysics"
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2204.09000 [pdf]
Galaxies(2022)·27 citations
06
[Submitted on 18 Apr 2022] (cross-list from astro-ph.HE)
Constraining the equation of state of neutron stars using multimessenger observations
Bhaskar Biswas🇮🇳
Neutron stars are the densest objects known in our visible universe. Properties of matter inside a neutron star are encoded in its equation of state, which has wide-ranging uncertainty from a theoretical perspective. With the current understanding of quantum chromodynamics, it is hard to determine the interactions of neutron star matter at such high densities. Also performing many body calculations is computationally intractable. Besides the constitution of the neutron star core is highly speculative -- it is not ruled out that it contains exotic matter like strange baryons, meson condensates, quark matter, etc. Although the matter inside the neutron star is extremely dense, but the temperature of this object is very cold in most of its life span. We cannot produce such dense but rather cold material in our laboratory. Since probing the physics of neutron star matter is inaccessible by our earth based experiments, we look for astrophysical observations of neutron stars. This thesis deals with the theoretical and computational techniques required to translate neutron star observables from astrophysical observations to its equation of state.
Comments:
PhD thesis
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2204.08555 [pdf]
0 citations
07
[Submitted on 18 Apr 2022] (cross-list from hep-ph)
Bottomonium-like tetraquarks in a chiral quark model
Gang Yang🇨🇳 · Jialun Ping🇨🇳 · Jorge Segovia🇪🇸
The low-lying bottomonium-like tetraquarks $b b ˉ q q ˉ$ $(q = u, d, s)$ with spin-parity $J^{P} = 0^{+}$ , $1^{+}$ and $2^{+}$ , and isospin $I = 0, 1$ or $\frac{1}{2}$ , are systematically investigated within the theoretical framework of real- and complex-scaling range of a chiral quark model, which has already been successfully applied in analysis of several multiquark systems. A complete four-body $S$ -wave function, which includes meson-meson, diquark-antidiquark and K-type arrangements of quarks, along with all possible color configurations are considered. In the $b b ˉ q q ˉ$ $(q = u, d)$ tetraquark system, we found resonance states of $B^{(*)} B ˉ^{(*)}$ , $Υ ω$ , $Υ ρ$ and $η_{b} ρ$ nature with all possible $I (J^{P})$ quantum numbers. Their masses are generally located in the energy range $11.0 - 11.3$ GeV and their widths are less than $10$ MeV. In addition, extremely narrow resonances, with two-meson strong decay widths less than $1.5$ MeV, are obtained in both $b b ˉ u s ˉ$ and $b b ˉ s s ˉ$ tetraquark systems. Particularly, four radial excitations of $Υ K^{*}$ and $η_{b} K^{*}$ are found at $\sim 11.1$ GeV in $J^{P} = 0^{+}$ , $1^{+}$ and $2^{+}$ channels of $b b ˉ u s ˉ$ system. One $Υ (1 S) ϕ (2 S)$ resonance state is obtained at $11.28$ GeV in the $J^{P} = 1^{+}$ sector.
Comments:
19 pages, 16 tables and 13 figures. arXiv admin note: substantial text overlap with arXiv:2101.04933, arXiv:2109.04311
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:
2204.08556 [pdf]
PRD(2022)·8 citations
08
[Submitted on 19 Apr 2022] (cross-list from hep-ph)
Chiral perturbation theory for heavy hadrons and chiral effective field theory for heavy hadronic molecules
Lu Meng🇩🇪 · Bo Wang🇨🇳 · Guang-Juan Wang🇯🇵 · Shi-Lin Zhu🇨🇳
Chiral symmetry and its spontaneous breaking play an important role both in the light hadron and heavy hadron systems. The chiral perturbation theory ( $χ$ PT) is the low energy effective field theory of the QCD. In this work, we shall review the investigations on the chiral corrections to the properties of the heavy mesons and baryons within the framework of $χ$ PT. We will also review the scatterings of the light pseudoscalar mesons and heavy hadrons, through which many new resonances such as the $D_{s 0}^{*} (2317)$ could be understood. Moreover, many new hadron states were observed experimentally in the past decades. A large group of these states is near-threshold resonances, such as the charged charmoniumlike $Z_{c}$ and $Z_{cs}$ states, bottomoniumlike $Z_{b}$ states, hidden-charm pentaquark $P_{c}$ and $P_{cs}$ states and the doubly charmed $T_{cc}$ state, etc. They are very good candidates of the loosely bound molecular states composed of a pair of charmed (bottom) hadrons, which are very similar to the loosely bound deuteron. The modern nuclear force was built upon the chiral effective field theory ( $χ$ EFT), which is the extension of the $χ$ PT to the systems with two matter fields. The long-range and medium-long-range interactions between two nucleons arise from the single- and double-pion exchange respectively, which are well constrained by the chiral symmetry and its spontaneous breaking. The short-distance interactions can be described by the low energy constants. Such a framework works very well for the nucleon-nucleon scattering and nuclei. In this work, we will perform an extensive review of the progress on the heavy hadronic molecular states within the framework of $χ$ EFT. We shall emphasize that the same chiral dynamics not only govern the nuclei and forms the deuteron, but also dictates the shallow bound states or resonances composed of two heavy hadrons.
Comments:
A Review on hadronic molecules in EFT frameworks with 178 pages and 69 figures; Accepted version by Physics Reports
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2204.08716 [pdf]
Phys.Rept.(2023)·347 citations
09
[Submitted on 19 Apr 2022] (cross-list from quant-ph)
Velocity-like maximum polarization: irreversibility and quantum measurements
Oleg Teryaev🇷🇺
The polarization emerging in the subsequent scattering processes can never exceed $1$ which corresponds to the fully polarized pure state. This property is shown to be provided by the addition rule similar to that for relativistic velocities never exceeding the speed of light. The cases of spin $1/2$ and $1$ are considered. The photon linear polarization in Thomson scattering is monotonically increasing. This directness is shown to be a consequence of spin measurement procedure and may be the particular example of ithe anticipated relation between quantum measurement and time irreversibility. The emergent polarization may be considered as a case of opposing time's arrows corresponding to microscopic (spin) and macroscopic (momentum) degrees of freedom, respectively.
Comments:
15 pages, no figures
Subjects:
Quantum Physics (quant-ph); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2204.08796 [pdf]
PRC(2022)·3 citations
10
[Submitted on 19 Apr 2022] (cross-list from nucl-ex)
Evolution of the $γ$ -ray strength function in neodymium isotopes
M. Guttormsen · K. O. Ay · M. Ozgur · E. Algin · A. C. Larsen · F. L. Bello Garrote · H. C. Berg · L. Crespo Campo · T. Dahl-Jacobsen · F. W. Furmyr · D. Gjestvang · A. Görgen and 15 other authors
The experimental gamma-ray strength functions (gamma-SFs) of 142,144-151Nd have been studied for gamma-ray energies up to the neutron separation energy. The results represent a unique set of gamma-SFs for an isotopic chain with increasing nuclear deformation. The data reveal how the low-energy enhancement, the scissors mode and the pygmy dipole resonance evolve with nuclear deformation and mass number. The data indicate that the mechanisms behind the low-energy enhancement and the scissors mode are decoupled from each other.
Comments:
14 pages and 10 figures
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2204.08852 [pdf]
PRC(2022)·27 citations
11
[Submitted on 19 Apr 2022] (cross-list from hep-ph)
$J / ψ$ near threshold in holographic QCD: A and D gravitational form factors
Kiminad A. Mamo🇺🇸 · Ismail Zahed🇺🇸
The diffractive photoproduction of $J /Ψ$ on a nucleon, is mostly due to gluonic exchanges at all $s$ . In holographic QCD (large number of colors and strong $^{'}$ t Hooft coupling), these exchanges are captured by gravitons near threshold, and their Reggeized Pomeron form asymptotically. We revisit our holographic analysis of the A and D gravitational form factors in light of the new lattice data, and use them to refine our predictions for the photoproduction of $J /Ψ$ near threshold, and the comparison to the GlueX data. We use these results to estimate the scalar and mass radii of the nucleon, and describe the gravitational pressure and shear across a nucleon.
Comments:
15 pages, 5 figures, 2 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2204.08857 [pdf]
PRD(2022)·94 citations

Affiliations

first authorsco-authorsvia INSPIRE