Nuclear Theory·nucl-th

Thursday·October 5, 2023

6 papers—3 primary·3 cross-listed

01
Modeling of nuclear reactions with Langevin calculations
S. Amano · Y. Aritomo · Y. Miyamoto · S. Ishizaki · M. Okubayashi
The mass angle distribution shows a strong correlation between mass and angle when quasifission events are dominant. Therefore, as long as quasifission events are dominant, the mass angle distribution is characterized in that a diagonal correlation appears. This diagonal correlation could not be reproduced in our previous model that is before introducing $f_{ina}$ and $γ_{t}^{0}$ model parameters. In this study, we clarify the indeterminate parameters included in the model to reproduce the diagonal correlation appearing in the mass angle distribution in the $^{48}$ Ti + $^{186}$ W reaction system. As a result, $f_{ina}$ and $γ_{t}^{0}$ of model parameters were found to be key parameters for MAD. it was also found that the balance between $f_{ina}$ and $γ_{t}^{0}$ parameter values is important for the strong correlation between mass and angle.
nucl-thBull.Russ.Acad.Sci.Phys.(2020)·1 citation
02
Ternary quasifission in collisions of actinide nuclei
D. D. Zhang · B. Li · D. Vretenar · T. Nikšić · Z. X. Ren · P. W. Zhao · J. Meng
The microscopic framework of time-dependent covariant density functional theory is applied to a systematic study of ternary quasifission in collisions of pairs of $^{238}$ U nuclei. It is shown that the inclusion of octupole degree of freedom in the case of head-to-head collisions, extends the energy window in which ternary quasifission occurs, and greatly enhances the number of nucleons contained in a middle fragment. Dynamical pairing correlations, included here in the time-dependent BCS approximation, prevent the occurrence of ternary quasifission in head-to-head collisions, and have an effect on the location of the energy window in which a middle fragment is formed in tail-to-tail collisions. In the latter case, as well as for tail-to-side collisions, the formation of very heavy neutron-rich systems in certain energy intervals is predicted.
nucl-thPRC(2024)·19 citations
03
Coupling strength induced BCS-BEC crossover on phase boundary of pion superfluid
Zhiyang Liu🇨🇳 · Shijun Mao🇨🇳
Coupling strength effect on the quark matter with finite isospin chemical potential is studied in a Pauli-Villars regularized NJL model. A BCS-BEC crossover occurs along the phase boundary of pion superfluid phase transition, as increasing coupling strength $G$ . For strong coupling cases, the critical isospin chemical potential for pion superfluid phase transition $μ_{I}^{c}$ is exactly the same as pion mass in vacuum $M_{π}$ . Around the critical point $μ_{I}^{c}$ , the pion superfluid quark matter is in BEC state, associated with a fast increase of pion condensate. For weak coupling cases, we obtain $μ_{I}^{c} < M_{π}$ , and a mass jump of the Goldstone boson at the critical point $μ_{I}^{c}$ . The pion superfluid quark matter is in BCS state even around $μ_{I}^{c}$ , accompanied by a slow increase of pion condensate. Note that $μ_{I}^{c}$ is a non-monotonic function of coupling strength $G$ . On the other hand, coupling strength effect changes the bulk properties of quark matter. In strong (weak) coupling cases, the EoS of quark matter at finite isospin chemical potential is stiff (soft). Therefore, the compact stars composed of strong (weak) coupling pion superfluid quark matter has a heavier (lighter) mass and larger (smaller) radius.
nucl-th0 citations
04
Can negative bare couplings make sense? The $ϕ^{4}$ theory at large $N$
Ryan D. Weller🇺🇸
Scalar $λ ϕ^{4}$ theory in 3+1D, for a positive coupling constant $λ > 0$ , is known to have no interacting continuum limit, which is referred to as quantum triviality. However, it has been recently argued that the theory in 3+1D with an $N$ -component scalar $ϕ$ and a $(ϕ \cdot ϕ)^{2} = ϕ^{4}$ interaction term does have an interacting continuum limit at large $N$ . It has been suggested that this continuum limit has a negative (bare) coupling constant and exhibits asymptotic freedom, similar to the $P T$ -symmetric $- g ϕ^{4}$ field theory. In this paper I study the $ϕ^{4}$ theory in 3+1D at large $N$ with a negative coupling constant $- g < 0$ , and with the scalar field taking values in a $P T$ -symmetric complex domain. The theory is non-trivial, has asymptotic freedom, and has a Landau pole in the IR, and I demonstrate that the thermal partition function matches that of the positive-coupling $λ > 0$ theory when the Landau poles of the two theories (in the $λ > 0$ case a pole in the UV) are identified with one another. The spirit of renormalization is that observables do not depend on the renormalization scale. Here we see even if the coupling is taken negative above the scale of the Landau pole, thermodynamic observables are unaffected. Thus the $ϕ^{4}$ theory at large $N$ appears to have a negative bare coupling constant; the coupling only becomes positive in the IR, which in the context of other $P T$ -symmetric and large- $N$ quantum field theories I argue is perfectly acceptable.
↳ hep-thhep-phnucl-th13 citations
05
Anisotropy of magnetized quark matter
Kangkan Goswami🇮🇳 · Dushmanta Sahu🇮🇳 · Jayanta Dey🇮🇳 · Raghunath Sahoo🇮🇳 · Reinhard Stock🇮🇳
Strong transient magnetic fields are generated in non-central relativistic heavy-ion collisions. These fields induce anisotropy within the strongly interacting medium that, in principle, can affect the thermodynamic properties of the medium. We use the Polyakov loop extended Nambu Jona-Lasinio model to study the quark matter subjected to an external magnetic field at vanishing baryon chemical potential ( $μ_{B}$ ). We have estimated the degree of anisotropy in the speed of sound and isothermal compressibility within the magnetized quark matter as a function of temperature ( $T$ ) and magnetic field ( $e B$ ). This study helps us to understand the extent of directionality generated in the initial stages of non-central collisions while giving us useful information about the system.
↳ hep-phhep-exnucl-exnucl-thPRD(2024)·18 citations
06
Optimized simulations of 50Ti(p,{\alpha}) and 49Ti(d,{\alpha}) reactions for hospital-cyclotron production of 47Sc
F. Barbaro · L. Canton · Y. Lashko · L. Zangrando
The production of 47Sc, a promising radioisotope for targeted radionuclide therapy, by means of hospital-cyclotron reactions is investigated. Two possible routes are considered: the proton-induced reaction on enriched 50Ti targets and the deuteron-induced reaction on enriched 49Ti targets. The cross-sections of the reactions are calculated using the TALYS code with optimized parameters and compared with the available experimental data. The optimal energy ranges for the production of 47Sc are determined by taking into account the thick-target yields and the purity of the product. The results show that both reactions can provide high yields and high purity of 47Sc. The feasibility of producing 47Sc with a hospital cyclotron is demonstrated by performing realistic simulations of the irradiation for both 50Ti(p,{\alpha}) and 49Ti(d,{\alpha}) reactions.
↳ physics.med-phnucl-thEPJ Web Conf.(2024)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE

Modeling of nuclear reactions with Langevin calculations

Ternary quasifission in collisions of actinide nuclei

Coupling strength induced BCS-BEC crossover on phase boundary of pion superfluid

Can negative bare couplings make sense? The ϕ​4 theory at large N

Anisotropy of magnetized quark matter

Optimized simulations of 50Ti(p,{\alpha}) and 49Ti(d,{\alpha}) reactions for hospital-cyclotron production of 47Sc

Affiliations

Can negative bare couplings make sense? The $ϕ^{4}$ theory at large $N$