Nuclear Theory·nucl-th

Thursday·March 9, 2023

12 papers—6 primary·6 cross-listed

01
Analytic continuation of the relativistic three-particle scattering amplitudes
Sebastian M. Dawid🇺🇸 · Md Habib E Islam🇺🇸 · Raúl A. Briceño🇺🇸
We investigate the relativistic scattering of three identical scalar bosons interacting via pair-wise interactions. Extending techniques from the non-relativistic three-body scattering theory, we provide a detailed and general prescription for solving and analytically continuing integral equations describing the three-body reactions. We use these techniques to study a system with zero angular momenta described by a single scattering length leading to a bound state in a two-body sub-channel. We obtain bound-state--particle and three-particle amplitudes in the previously unexplored kinematical regime; in particular, for real energies below elastic thresholds and complex energies in the physical and unphysical Riemann sheets. We extract positions of three-particle bound-states that agree with previous finite-volume studies, providing further evidence for the consistency of the relativistic finite-volume three-body quantization conditions. We also determine previously unobserved virtual bound states in this theory. Finally, we find numerical evidence of the breakdown of the two-body finite-volume formalism in the vicinity of the left-hand cuts and argue for the generalization of the existing formalism.
nucl-thhep-lathep-phPRD(2023)·64 citations
02
High-density symmetry energy from subthreshold hyperon production in heavy-ion collisions
Zhao-Qing Feng🇨🇳
The hyperon dynamics in heavy-ion collisions near threshold energy has been investigated within the quantum molecular dynamics transport model. The isospin and momentum dependent hyperon-nucleon potential and the threshold energy correction on the hyperon elementary cross section are included in the model. It is found that the high-density symmetry energy is dependent on the isospin ratios $Σ^{-} / Σ^{+}$ and $Ξ^{-} / Ξ^{0}$ , in particular in the domain of high kinetic energies. The isospin diffusion in heavy-ion collisions influences the neutron/proton ratio in the high-density region. The $Σ^{-} / Σ^{+}$ ratio depends on the stiffness of symmetry energy, in particular at the beam energy below the threshold value (E $_{t h}$ =1.58 GeV), i.e., the kinetic energy spectra of the single ratios, excitation functions and energy spectra of the double ratios in the isotopic reactions of $^{108}$ Sn + $^{112}$ Sn, $^{112}$ Sn + $^{112}$ Sn, $^{124}$ Sn + $^{124}$ Sn and $^{132}$ Sn + $^{124}$ Sn. The double strangeness ratio $Ξ^{-} / Ξ^{0}$ weakly depends on the symmetry energy because of the hyperon-hyperon collision mainly contributing the $Ξ$ production below the threshold energy (E $_{t h}$ = 3.72 GeV).
nucl-thPLB(2023)·4 citations
03
An algebraic approach to intertwined quantum phase transitions in the Zr isotopes
N. Gavrielov
The algebraic framework of the interacting boson model with configuration mixing is employed to demonstrate the occurrence of intertwined quantum phase transitions (IQPTs) in the $_{40}$ Zr isotopes with neutron number 52-70. The detailed quantum and classical analyses reveal a QPT of crossing normal and intruder configurations superimposed on a QPT of the intruder configuration from U(5) to SU(3) and a crossover from SU(3) to SO(6) dynamical symmetries.
nucl-thSciPost Phys.Proc.(2023)·0 citations
04
Prolate-oblate asymmetric shape phase transition in the interacting boson model with SU (3) higher-order interactions
Tao Wang · Bing-cheng He · Dong-kang Li · Chun-xiao Zhou
Prolate-oblate shape phase transition is an interesting topic in nuclear structure, which is useful for understanding the intrinsic interactions between nucleons. Recently, the interacting boson model with $S U (3)$ higher-order interactions was proposed, in which the prolate shape and the oblate shape are not described in a mirror symmetric way. This asymmetric description seems more realistic. The level evolutions, $B (E 2)$ values and other important indicators showing the prolate-oblate asymmetric transitions are investigated in detail, and realistic structure evolutions from $^{180}$ Hf to $^{200}$ Hg are compared. A key finding is that, the average deformation of the prolate shape is nearly twice the one of the oblate shape. These results, together with the successful description of the $B (E 2)$ anomaly in $^{168, 170}$ Os, $^{172}$ Pt, the $γ$ -soft properties of $^{196}$ Pt, $^{82}$ Kr and the normal states of $^{110}$ Cd, support the validity of the new model.
nucl-thPRC(2023)·13 citations
05
Speed of Sound in Hybrid Stars and the Role of Bag Pressure in the Emergence of Special Points on M-R Variation of Hybrid Stars
Suman Pal🇮🇳 · Soumen Podder🇮🇳 · Debashree Sen🇮🇳 · Gargi Chaudhuri🇮🇳
We compute the hybrid star (HS) properties with the help of Maxwell construction. For the purpose we choose a fixed hadronic model and four different forms of MIT bag model for the quark phase. We investigate thoroughly the effects of the different parameters of the bag model on the speed of sound in HS matter and the structural properties of HSs in the light of the various recent constraints on them from astrophysical observations. We also examine the importance of each parameter involved in these four forms of bag model in the context appearance of special points (SPs) in the mass-radius (M-R) variation of HSs. We find that among all these parameters the bag pressure play the most significant role in the emergence of the SPs in the M-R dependence of HSs.
nucl-thhep-phPRD(2023)·29 citations
06
Entanglement entropy of nuclear systems
Chenyi Gu · Z. H. Sun · G. Hagen · T. Papenbrock
We study entanglement entropies between the single-particle states of the hole space and its complement in nuclear systems. Analytical results based on the coupled-cluster method show that entanglement entropies are proportional to the particle number fluctuation and the depletion number of the hole space for sufficiently weak interactions. General arguments also suggest that the entanglement entropy in nuclear systems fulfills a volume instead of an area law. We test and confirm these results by computing entanglement entropies of the pairing model and neutron matter, and the depletion number of finite nuclei.
nucl-thquant-phPRC(2023)·50 citations
07
Neutrinoless double-beta decay in the neutrino-extended Standard Model
Wouter Dekens🇺🇸 · Jordy de Vries🇳🇱 · Emanuele Mereghetti🇺🇸 · Javier Menéndez🇪🇸 · Pablo Soriano🇪🇸 · Guanghui Zhou🇨🇳
We investigate neutrinoless double-beta decay ( $0 ν β β$ ) in the minimal extension of the standard model of particle physics, the $ν$ SM, where gauge-singlet right-handed neutrinos give rise to Dirac and Majorana neutrino mass terms. We focus on the associated sterile neutrinos and argue that the usual evaluation of their contributions to $0 ν β β$ , based on mass-dependent nuclear matrix elements, is missing important contributions from neutrinos with ultrasoft and hard momenta. We identify the hadronic and nuclear matrix elements that enter the new contributions, and calculate all relevant nuclear matrix elements for $^{136}$ Xe using the nuclear shell model. Finally, we illustrate the impact on $0 ν β β$ rates in specific neutrino mass models and show that the new contributions significantly alter the $0 ν β β$ rate in most parts of the $ν$ SM parameter space.
↳ hep-phhep-exnucl-exnucl-thPRC(2023)·37 citations
08
Analogies between hadron-in-jet and dihadron fragmentation
Alessandro Bacchetta🇮🇹 · Marco Radici🇮🇹 · Lorenzo Rossi🇮🇹
We describe the formal analogies in the description of the inclusive production in hard processes of hadron pairs (based on dihadron fragmentation functions) and of a single hadron inside a jet (based on hadron-in-jet fragmentation functions). Since several observables involving dihadron fragmentation functions have been proposed in the past, we are able to suggest new interesting observables involving hadron-in-jet fragmentation functions, in lepton-hadron deep-inelastic scattering and hadronic collisions.
↳ hep-phhep-exnucl-exnucl-thPRD(2023)·7 citations
09
A possibility of existence of a pseudovector-type quark-antiquark condensate in the quark matter and Nambu-Goldstone modes on that condensate in the Nambu-Jona-Lasinio model
Kentaro Hayashi (Kochi Univ., Japan)🇯🇵 · Yasuhiko Tsue (Kochi Univ., Japan)🇯🇵
A possibility of a pseudovector-type quark-antiquark condensed phase, which leads to a quark spin polarized phase, in the quark matter is investigated taking account of the vacuum effects leading to the chiral symmetry breaking by using the Nambu-Jona-Lasinio model. Also, possible Nambu-Goldstone modes on the pseudovector-type quark-antiquark condensate and the tensortype quark-antiquark condensate, which also leads to the quark spin polarized phase, are investigated.
↳ hep-phnucl-thIJMPE(2023)·1 citation
10
Deep learning for flow observables in ultrarelativistic heavy-ion collisions
H. Hirvonen🇫🇮 · K. J. Eskola🇫🇮 · H. Niemi🇫🇮
We train a deep convolutional neural network to predict hydrodynamic results for flow coefficients, average transverse momenta and charged particle multiplicities in ultrarelativistic heavy-ion collisions from the initial energy density profiles. We show that the neural network can be trained accurately enough so that it can reliably predict the hydrodynamic results for the flow coefficients and, remarkably, also their correlations like normalized symmetric cumulants, mixed harmonic cumulants and flow-transverse-momentum correlations. At the same time the required computational time decreases by several orders of magnitude. To demonstrate the advantage of the significantly reduced computation time, we generate 10M initial energy density profiles from which we predict the flow observables using the neural network, which is trained using 5k, and validated using 90k events per collision energy. We then show that increasing the number of collision events from 90k to 10M can have significant effects on certain statistics-expensive flow correlations, which should be taken into account when using these correlators as constraints in the determination of the QCD matter properties.
↳ hep-phnucl-thPRC(2023)·16 citations
11
Scattering length and effective range of microscopic two-body potentials
Mathias Macêdo-Lima · Lucas Madeira
Scattering processes are a fundamental way of experimentally probing distributions and properties of systems in several areas of physics. Considering two-body scattering at low energies, when the de Broglie wavelength is larger than the range of the potential, partial waves with high angular momentum are typically unimportant. The dominant contribution comes from $l = 0$ partial waves, commonly known as $s$ -wave scattering. This situation is very relevant in atomic physics, e.g. cold atomic gases, and nuclear physics, e.g. nuclear structure and matter. This manuscript is intended as a pedagogical introduction to the topic while covering a numerical approach to compute the desired quantities. We introduce low-energy scattering with particular attention to the concepts of scattering length and effective range. These two quantities appear in the effective-range approximation, which universally describes low-energy processes. We outline a numerical procedure for calculating the scattering length and effective range of spherically symmetric two-body potentials. As examples, we apply the method to the spherical well, modified Pöschl-Teller, Gaussian, and Lennard-Jones potentials. We hope to provide the tools so students can implement similar calculations and extend them to other potentials.
↳ quant-phcond-mat.quant-gasnucl-thphysics.atom-phRev.Bras.Ens.Fis.(2023)·9 citations
12
Magnetic enhancement of baryon confinement modeled via a deformed Skyrmion
Shi Chen🇯🇵 · Kenji Fukushima🇯🇵 · Zebin Qiu🇯🇵
We discuss the baryon properties under a strong magnetic field. We adopt the Skyrme model and calculate the magnetic field dependence of the mass and the pressure distribution in the soliton. We elucidate a magnetically induced contribution to the pressure sum rule and interpret it as an extra confining force. We also quantize the soliton to estimate the difference between the proton and the neutron and find a simple relation between the pressure and the mass differences.
↳ hep-thnucl-thPLB(2023)·18 citations

Affiliations

first authorsco-authorsvia INSPIRE