Nuclear Theory·nucl-th

Tuesday·October 11, 2022

18 papers—12 primary·6 cross-listed

01
Fast rotation of nuclei with extreme isospin in the vicinity of neutron and proton drip lines
A. V. Afanasjev · S. Teeti · A. Taninah
The analysis of the present understanding of collective rotation in very neutron-rich nuclei is presented. It is shown that collective rotation can lead to the increase of stability of rotational states with increasing spin. The detailed investigation of rotational excitations in very proton-rich nuclei confirms this conclusion and indicate that experimental studies of such features are more feasible in the nuclei near proton drip line. They also show that rotational bands which are proton quasi-bound at zero or low spins can be transformed into proton bound ones at high spin by collective rotation of nuclear systems. This is due to strong Coriolis interaction which acts on high- $j$ or strongly mixed M orbitals and drives the highest in energy occupied single-particle states into negative energy domain. These physical mechanisms lead to a substantial extension of the nuclear landscape beyond the spin zero proton drip line. In addition, a new phenomenon of the formation of giant proton halos in rotating nuclei emerges: it is triggered by the occupation of strongly mixed M intruder orbitals.
nucl-thPhys.Scripta(2024)·1 citation
02
Using Baryonic Charge Balance Functions to Resolve Questions about the Baryo-Chemistry of the QGP
Scott Pratt🇺🇸 · Dmytro Oliinychenko🇺🇸 · Chris Plumberg🇺🇸
Baryon annihilations during the hadronic stage of heavy-ion collisions affects final-state baryon and antibaryon yields and final-state correlations of baryons and antibaryons. Understanding annihilation is important for addressing questions about the chemistry at the beginning of the hadronic stage, and for interpreting charge-balance correlations involving baryons. Here, charge balance functions, using protons and antiprotons binned by relative momentum, rapidity and azimuthal angle, are shown to clarify the amount of annihilation in the hadronic stage. This enables a more accurate extraction of the baryo-chemistry at the beginning of the hadronic stage. Understanding annihilation is also crucial if charge balance correlations are to be used to infer the chemistry of the earliest stages of a heavy-ion collision. Calculations are presented based on microscopic simulations of the hadronic stage coupled to a hydrodynamic description of the earlier stage, along with a detailed modeling of correlations of protons and antiprotons, known as charge-balance functions.
nucl-thPRC(2022)·6 citations
03
Bremsstrahlung photon from a hadronizing quark-gluon plasma
Taesoo Song🇩🇪
Assuming that quark and antiquark numbers are separately conserved during hadronization, we calculate Bremsstrahlung photon from a hadronizing quark-gluon plasma. The quark and antiquark numbers are obtained from the hadron numbers in the statistical model and the transition amplitudes for the hadronization from the constraint that all quarks and antiquarks must be consumed in the hadronization. Then Bremsstrahlung photon from the hadronization is obtained in the soft photon approximation, and we find that its contribution to the direct photon increases in low-energy heavy-ion collisions and in peripheral collisions where the lifetime of a quark-gluon plasma (QGP) is relatively short.
nucl-thhep-phPRC(2023)·5 citations
04
Soft gluon emission from heavy quark scattering in strongly interacting quark-gluon plasma
Taesoo Song🇩🇪 · Ilia Grishmanovskii🇩🇪 · Olga Soloveva🇩🇪
We apply the Low's theorem to soft gluon emission from heavy quark scattering in the nonperturbative strongly interacting quark-gluon plasma (sQGP). The sQGP is described in terms of the dynamical quasi-particles and adjusted to reproduce the EoS from lQCD at finite temperature and chemical potential. Since the emitted gluon is soft and of long wavelength, it does not provide information on the detailed structure of the scattering, and only the emission from incoming and outgoing partons is enough. It simplifies the calculations making the scattering amplitude factorizable into the elastic scattering and the emission of soft gluon. Imposing a proper upper limit on the emitted gluon energy, we obtain the guage-invariant scattering cross sections of heavy quarks with the massive partons of the medium as well as their transport coefficients (momentum drag and diffusion) in the QGP and compare with those from the elastic scattering without gluon emission.
nucl-thhep-phPRD(2023)·15 citations
05
Big Bang nucleosynthesis as a probe of new physics
Carlos A. Bertulani🇺🇸 · Francis W. Hall🇺🇸 · Benjamin I. Santoyo🇺🇸
The Big Bang Nucleosynthesis (BBN) model is a cornerstone for the understanding of the evolution of the early universe, making seminal predictions that are in outstanding agreement with the present observation of light element abundances in the universe. Perhaps, the only remaining issue to be solved by theory is the so-called "lithium abundance problem". Dedicated experimental efforts to measure the relevant nuclear cross sections used as input of the model have lead to an increased level of accuracy in the prediction of the light element primordial abundances. The rise of indirect experimental techniques during the preceding few decades has permitted the access of reaction information beyond the limitations of direct measurements. New theoretical developments have also opened a fertile ground for tests of physics beyond the standard model of atomic, nuclear, statistics, and particle physics. We review the latest contributions of our group for possible solutions of the lithium problem.
nucl-thastro-ph.COEPJ Web Conf.(2023)·8 citations
06
Physical Implications of the Extrapolation and Statistical Bootstrap of the Nucleon Structure Function Ratio $\frac{F _{2}^{n}}{F _{2}^{p}}$ for Mirror Nuclei $^{3}$ He and $^{3}$ H
Hannah Valenty🇺🇸 · Jennifer Rittenhouse West🇺🇸 · Fatiha Benmokhtar🇺🇸 · Douglas W. Higinbotham🇺🇸 · Asia Parker🇺🇸 · Erin Seroka🇺🇸
A nuclear physics example of statistical bootstrap is used on the MARATHON data nucleon structure function ratio, $\frac{F _{2}^{n}}{F _{2}^{p}}$ , in the quark momentum fraction $x_{B} \to 0$ and $x_{B} \to 1$ regions. The extrapolated $F_{2}$ ratio value as quark momentum fraction $x_{B} \to 1$ approaches 0.4 and this value is compared to theoretical predictions. The extrapolated ratio when $x_{B} \to 0$ favors the simple model of isospin symmetry with the complete dominance of seaquarks at low momentum fraction. At high- $x_{B}$ , the proton quark distribution function ratio $d / u$ is derived from the $x \to 1$ ratio $\frac{F _{2}^{n}}{F _{2}^{p}} \to 0.4$ and found to be $d / u \to 1/6$ . Our extrapolated values for both the $\frac{F _{2}^{n}}{F _{2}^{p}}$ ratio and the $d / u$ parton distribution function ratio most closely match perturbative QCD values from quark counting and helicity conservation arguments but still differ by roughly $7%$ . The mismatch to theoretical predictions may be ameliorated if two compatible models act simultaneously in the nucleon wavefunction. One such example is nucleon wavefunctions composed of a linear combination of a quark-diquark state and a 3-valence quark correlated state with coefficients that combine to give the extrapolated $F_{2}$ ratio of $0.4$ .
nucl-thhep-phnucl-exPRC(2023)·2 citations
07
Supernova Neutrinos as a Precise Probe of Nuclear Neutron Skin
Xu-Run Huang🇨🇳 · Lie-Wen Chen🇨🇳
A precise and model-independent determination of the neutron distribution radius $R_{n}$ and thus the neutron skin thickness $R_{skin}$ of atomic nuclei is of fundamental importance in nuclear physics, particle physics and astrophysics but remains a big challenge in terrestrial labs. We argue that the nearby core-collapse supernova (CCSN) in our Galaxy may render a neutrino flux with unprecedentedly high luminosity, offering perfect opportunity to determine the $R_{n}$ and $R_{skin}$ through the coherent elastic neutrino-nucleus scattering (CE $ν$ NS). We evaluate the potential of determining the $R_{n}$ of lead (Pb) via CE $ν$ NS with the nearby CCSN neutrinos in the RES-NOVA project which is designed to hunt CCSN neutrinos using an array of archaeological Pb based cryogenic detectors. We find that an ultimate precision of $\sim 0.1%$ for the $R_{n}$ ( $\sim 0.006$ fm for the $R_{skin}$ ) of Pb can be achieved via RES-NOVA in the most optimistic case that the CCSN explosion were to occur at a distance of $\sim 1$ kpc from the Earth.
nucl-thastro-ph.HEhep-phnucl-exPRD(2022)·9 citations
08
Cluster structures of the $0^{+}$ states of $_{Λ}^{13} C$ with the 3 $α + Λ$ four-body orthogonality condition model
Qian Wu🇨🇳 · Yasuro Funaki🇯🇵 · Xurong Chen🇨🇳
We study structures of the $0^{+}$ states of $_{Λ}^{13}$ C within the framework of $α + α + α + Λ$ four-body orthogonality condition model with the Gaussian expansion method. We obtain five $0^{+}$ states of $_{Λ}^{13}$ C and compare them with the low-lying four $0^{+}$ states of $^{12}$ C. We find that the $0_{1}^{+}$ , $0_{2}^{+}$ and $0_{4}^{+}$ states correspond to the $0_{1}^{+}$ , $0_{2}^{+}$ and $0_{4}^{+}$ states of $^{12}$ C, respectively. We also find that both the $0_{3}^{+}$ and $0_{5}^{+}$ states have analogous nature to the $0_{3}^{+}$ state of $^{12}$ C, where the additional $Λ$ particle couples with $^{8}$ Be cluster and one $α$ cluster, in the $0_{3}^{+}$ state of $^{12}$ C, respectively. The former is then shown to have an elongated $_{Λ}^{9}$ Be $(0_{1}^{+}) + α$ cluster structure with a higher nodal behaviour for their relative wave function, and the latter have a dilute three-body gas consisting of $2 α +_{Λ}^{5}$ He clusters.
nucl-thPRC(2023)·4 citations
09
Uncertainty quantification in electromagnetic observables of nuclei
Bijaya Acharya🇩🇪 · Sonia Bacca🇩🇪 · Francesca Bonaiti🇩🇪 · Simone Salvatore Li Muli🇩🇪 · Joanna E. Sobczyk🇩🇪
We present strategies to quantify theoretical uncertainties in modern ab-initio calculations of electromagnetic observables in light and medium-mass nuclei. We discuss how uncertainties build up from various sources, such as the approximations introduced by the few- or many-body solver and the truncation of the chiral effective field theory expansion. We review the recent progress encompassing a broad range of electromagnetic observables in stable and unstable nuclei.
nucl-thFront.Phys.(2023)·12 citations
10
Charmonium transport in the high- $μ_{B}$ medium
Jiaxing Zhao🇨🇳 · Baoyi Chen🇨🇳
We employ the transport model coupled with hydrodynamic equations to study the charmonium dissociation and regeneration in the quark-gluon plasma (QGP) with the large baryon chemical potential in Au-Au collisions at the energies of $s_{N N} =$ ( $39$ , $14.5$ , $7.7$ ) GeV. The baryon chemical potential $μ_{B}$ is encoded in both Debye mass characterizing the heavy-quark potential and also the equation of state (EoS) of the bulk medium respectively. After considering $μ_{B}$ -corrections in both heavy quarkonium and the QGP medium, we calculate the nuclear modification factor $R_{AA}$ of charmonium. And find the $μ_{B}$ influence on charmonium production at $s_{N N}$ = 39 and 14.5 GeV is negligible, while the $R_{AA}$ of charmonium is reduced considering $μ_{B}$ influence at $s_{N N} = 7.7$ GeV Au-Au collisions. It is crucial for studying charmonium production in low energy and also fixed-target heavy-ion collisions.
nucl-thPRC(2023)·3 citations
11
Low-energy M1 states in deformed nuclei: spin-scissors or spin-flip?
V. O. Nesterenko · P. I. Vishnevskiy · A. Repko · J. Kvasil
The low-energy $M 1$ states in deformed $^{164}$ Dy and spherical $^{58}$ Ni are explored in the framework of fully self-consistent Quasiparticle Random-Phase Approximation (QRPA) with various Skyrme forces. The main attention is paid to orbital and spin $M 1$ excitations. The obtained results are compared with the prediction of the low-energy {\it spin-scissors} $M 1$ resonance suggested within Wigner Function Moments (WFM) approach. A possible relation of this resonance to low-energy spin-flip excitations is analyzed. In connection with recent WFM studies, we consider evolution of the low-energy spin-flip states in $^{164}$ Dy with deformation (from the equilibrium value to the spherical limit). The effect of tensor forces is briefly discussed. It is shown that two groups of $1^{+}$ states observed at 2.4-4 MeV in $^{164}$ Dy are rather explained by fragmentation of the orbital $M 1$ strength than by the occurrence of the collective spin-scissors resonance. In general, our calculations do not confirm the existence of this resonance.
nucl-thPhys.Atom.Nucl.(2022)·2 citations
12
Dilepton Decay of Low-mass $ρ$ Mesons
K. Gallmeister🇩🇪 · U. Mosel🇩🇪 · L. von Smekal🇩🇪
The HADES collaboration has extracted dilepton mass spectra for $π^{-}$ induced reactions on the proton from a comparison of data taken on C and CH $_{2}$ targets. The spectra were interpreted in terms of different versions of vector meson dominance. Here we present results obtained from the theory and generator GiBUU. We first check the subtraction procedure used and then discuss the obtained mass spectra for the proton target. We point out that any conclusions on the version of VMD requires the knowledge of the $ρ$ spectral function in the interesting mass region.
nucl-thhep-exnucl-exPRC(2022)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE