arXiv: Nuclear Theory最新文献_第3页

Three-body structure of B19: Finite-range effects in two-neutron halo nuclei B19的三体结构:双中子晕核的有限范围效应

arXiv: Nuclear Theory Pub Date : 2020-11-10 DOI: 10.1103/PhysRevC.102.051304

J. Casal, E. Garrido

{"title":"Three-body structure of \u0000B19\u0000: Finite-range effects in two-neutron halo nuclei","authors":"J. Casal, E. Garrido","doi":"10.1103/PhysRevC.102.051304","DOIUrl":"https://doi.org/10.1103/PhysRevC.102.051304","url":null,"abstract":"The structure and $B(E1)$ transition strength of $^{19}$B are investigated in a $^{17}text{B}+n+n$ model, triggered by a recent experiment showing that $^{19}$B exhibits a well pronounced two-neutron halo structure. Preliminary analysis of the experimental data were made by employing contact $n$-$n$ interactions, which are known to underestimate the $s$-wave content in other halo nuclei such as $^{11}$Li. In the present work, the three-body hyperspherical formalism with finite-range two-body interactions is used to describe $^{19}$B. In particular, two different finite range $n$-$n$ interactions will be used, as well as a simple central Gaussian potential whose range is progressively reduced. The purpose is to determine the main properties of the nucleus and investigate how they change when using contact-like $n$-$n$ potentials. Special attention is also paid to the dependence on the prescription used to account for three-body effects, i.e., a three-body force or a density-dependent $n$-$n$ potential. We have found that the three-body model plus finite range potentials provide a description of $^{19}$B consistent with the experimental data. The results are essentially independent of the short-distance details of the two-body potentials, giving rise to an $(s_{1/2})^2$ content of about 55%, clearly larger than the initial estimates. Very little dependence has been found as well on the prescription used for the three-body effects. The total computed $B(E1)$ strength is compatible with the experimental result, although we slightly overestimate the data around the low-energy peak of the $dB(E1)/dvarepsilon$ distribution. Finally, we show that a reduction of the $n$-$n$ interaction range produces a significant reduction of the $s$-wave contribution, which then should be expected in calculations using contact interactions.","PeriodicalId":8463,"journal":{"name":"arXiv: Nuclear Theory","volume":"96 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77780559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Pseudorapidity distributions of charged particles in pp($rmoverline{p}$), p(d)A and AA collisions using Tsallis thermodynamics 用Tsallis热力学研究pp($rmoverline{p}$)， p(d)A和AA碰撞中带电粒子的赝快度分布

arXiv: Nuclear Theory Pub Date : 2020-11-10 DOI: 10.1088/1361-6471/ac1393

J. Tao, M. Wang, H. Zheng, W. C. Zhang, L. L. Zhu, A. Bonasera

引用次数: 5

Shear viscosity and electric conductivity of a hot and dense QGP with a chiral phase transition 具有手性相变的热致密QGP的剪切粘度和电导率

arXiv: Nuclear Theory Pub Date : 2020-11-06 DOI: 10.1103/PhysRevC.103.054901

O. Soloveva, D. Fuseau, J. Aichelin, E. Bratkovskaya

{"title":"Shear viscosity and electric conductivity of a hot and dense QGP with a chiral phase transition","authors":"O. Soloveva, D. Fuseau, J. Aichelin, E. Bratkovskaya","doi":"10.1103/PhysRevC.103.054901","DOIUrl":"https://doi.org/10.1103/PhysRevC.103.054901","url":null,"abstract":"We calculate two transport coefficients -- the shear viscosity over entropy ratio $eta/s$ and the ratio of the electric conductivity to the temperature $sigma_0/T$ -- of strongly interacting quark matter within the extended $N_f=3$ Polyakov Nambu-Jona-Lasinio (PNJL) model along the crossover transition line for moderate values of baryon chemical potential $0 leq mu_B leq 0.9$ GeV as well as in the vicinity of the critical endpoint (CEP) and at large baryon chemical potential $mu_B=1.2$ GeV, where the first-order phase transition takes place. The evaluation of the transport coefficients is performed on the basis of the effective Boltzmann equation in the relaxation time approximation. We employ two different methods for the calculation of the quark relaxation times: i) using the averaged transition rate defined via thermal averaged quark-quark and quark-antiquark PNJL cross sections and ii) using the 'weighted' thermal averaged quark-quark and quark-antiquark PNJL cross sections. The $eta/s$ and $sigma_0/T$ transport coefficients have a similar temperature and chemical potential behavior when approaching the chiral phase transition for the both methods for the quark relaxation time, however, the differences grow with increasing temperature. We demonstrate the effect of the first-order phase transition and of the CEP on the transport coefficients in the deconfined QCD medium.","PeriodicalId":8463,"journal":{"name":"arXiv: Nuclear Theory","volume":"09 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86037090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Electric dipole moments of three-nucleon systems in the pionless effective field theory 无导有效场论中三核子系统的电偶极矩

arXiv: Nuclear Theory Pub Date : 2020-11-03 DOI: 10.1103/PhysRevC.104.024002

Zichao Yang, E. Mereghetti, L. Platter, M. Schindler, Jared Vanasse

引用次数: 2

Low-energy dipole excitation mode in O18 with antisymmetrized molecular dynamics 具有反对称分子动力学的O18的低能偶极子激发模式

arXiv: Nuclear Theory Pub Date : 2020-11-02 DOI: 10.1103/PHYSREVC.103.034312

Y. Shikata, Y. Kanada-En’yo

引用次数: 0

Multiplicity-dependent saturation momentum in p-Pb collisions at 5.02 TeV 5.02 TeV下p-Pb碰撞的多重相关饱和动量

arXiv: Nuclear Theory Pub Date : 2020-11-01 DOI: 10.1103/PHYSREVC.103.024911

T. Osada

{"title":"Multiplicity-dependent saturation momentum in \u0000p\u0000-Pb collisions at 5.02 TeV","authors":"T. Osada","doi":"10.1103/PHYSREVC.103.024911","DOIUrl":"https://doi.org/10.1103/PHYSREVC.103.024911","url":null,"abstract":"Semi-inclusive transverse momentum spectra observed in proton-proton and proton-lead nuclear collisions at LHC energies obey a geometric scaling with a scaling variable using multiplicity-dependent saturation momentum. The saturation momentum extracted from the experimental data is proportional to the 1/6 power of the hadron multiplicity in the final state. On the other hand, the system's transverse size is proportional to the 1/3 power of the multiplicity, and the saturation momentum and the transverse size of the system are strongly correlated with the hadron multiplicity in the final state. Since the saturation momentum is proportional to the average transverse momentum of hadrons, one predicts average transverse momentum is also proportional to the 1/6 power of the multiplicity, which is consistent with experimental results at the LHC energy. We found that a nuclear modification factor $R_{rm pPb}$ calculated by the multiplicity-dependent saturation momentum decreases at $p_{rm T} lesssim$ 1GeV/$c$ and that our model can partially explain the $R_{rm pPb}$'s behavior thought to be caused by nuclear shadowing. On the other hand, Cronin enhancement experimentally observed at $2 lesssim p_{rm T} lesssim $ 6 GeV/$c$ is not reproduced. However, the experimental result, including the Cronin effect, can be reproduced well by introducing $p_{rm T}$ dependence as a 4$sim$5% correction to the multiplicity-dependent saturation momentum.","PeriodicalId":8463,"journal":{"name":"arXiv: Nuclear Theory","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82705449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Extension of the Hauser-Feshbach fission fragment decay model to multichance fission Hauser-Feshbach裂变碎片衰变模型在多机会裂变中的推广

arXiv: Nuclear Theory Pub Date : 2020-10-26 DOI: 10.1103/PHYSREVC.103.014615

A. Lovell, T. Kawano, Shin Okumura, I. Stetcu, M. Mumpower, P. Talou

{"title":"Extension of the Hauser-Feshbach fission fragment decay model to multichance fission","authors":"A. Lovell, T. Kawano, Shin Okumura, I. Stetcu, M. Mumpower, P. Talou","doi":"10.1103/PHYSREVC.103.014615","DOIUrl":"https://doi.org/10.1103/PHYSREVC.103.014615","url":null,"abstract":"The Hauser-Feshbach fission fragment decay model, $mathtt{HF^3D}$, which calculates the statistical decay of fission fragments, has been expanded to include multi-chance fission, up to neutron incident energies of 20 MeV. The deterministic decay takes as input pre-scission quantities - fission probabilities and the average energy causing fission - and post-scission quantities - yields in mass, charge, total kinetic energy, spin, and parity. From these fission fragment initial conditions, the full decay is followed through both prompt and delayed particle emissions, allowing for the calculation of prompt neutron and $gamma$ properties, such as multiplicity and energy distributions, both independent and cumulative fission yields, and delayed neutron observables. In this work, we describe the implementation of multi-chance fission into the $mathtt{HF^3D}$ model, and show an example of prompt and delayed quantities beyond first-chance fission, using the example of neutron-induced fission on $^{235}$U. This expansion represents significant progress in consistently modeling the emission of prompt and delayed particles from fissile systems.","PeriodicalId":8463,"journal":{"name":"arXiv: Nuclear Theory","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89206015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

Scattering matrix pole expansions for complex wave numbers in R-matrix theory r -矩阵理论中复波数的散射矩阵极点展开

arXiv: Nuclear Theory Pub Date : 2020-10-24 DOI: 10.1103/PhysRevC.103.064609

P. Ducru, B. Forget, V. Sobes, G. Hale, M. Paris

{"title":"Scattering matrix pole expansions for complex wave numbers in \u0000R\u0000-matrix theory","authors":"P. Ducru, B. Forget, V. Sobes, G. Hale, M. Paris","doi":"10.1103/PhysRevC.103.064609","DOIUrl":"https://doi.org/10.1103/PhysRevC.103.064609","url":null,"abstract":"In this follow-up article to [Shadow poles in the alternative parametrization of R-matrix theory, Ducru (2020)], we establish new results on scattering matrix pole expansions for complex wavenumbers in R-matrix theory. In the past, two branches of theoretical formalisms emerged to describe the scattering matrix in nuclear physics: R-matrix theory, and pole expansions. The two have been quite isolated from one another. Recently, our study of Brune's alternative parametrization of R-matrix theory has shown the need to extend the scattering matrix (and the underlying R-matrix operators) to complex wavenumbers. Two competing ways of doing so have emerged from a historical ambiguity in the definitions of the shift $boldsymbol{S}$ and penetration $boldsymbol{P}$ functions: the legacy Lane & Thomas \"force closure\" approach, versus analytic continuation (which is the standard in mathematical physics). The R-matrix community has not yet come to a consensus as to which to adopt for evaluations in standard nuclear data libraries, such as ENDF. \u0000In this article, we argue in favor of analytic continuation of R-matrix operators. We bridge R-matrix theory with the Humblet-Rosenfeld pole expansions, and unveil new properties of the Siegert-Humblet radioactive poles and widths, including their invariance properties to changes in channel radii $a_c$. We then show that analytic continuation of R-matrix operators preserves important physical and mathematical properties of the scattering matrix -- cancelling spurious poles and guaranteeing generalized unitarity -- while still being able to close channels below thresholds.","PeriodicalId":8463,"journal":{"name":"arXiv: Nuclear Theory","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78777289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Roton instabilities in the superfluid outer core of neutron stars 中子星超流体外核的罗顿不稳定性

arXiv: Nuclear Theory Pub Date : 2020-10-24 DOI: 10.1103/PhysRevC.103.065803

J. A. Granados, A. M. Mateo, X. Viñas

引用次数: 0

Isovector pair correlations in analytically solvable models 解析可解模型中的等向量对相关性

arXiv: Nuclear Theory Pub Date : 2020-10-23 DOI: 10.1142/s0218301320500913

G. Nikoghosyan, A. Balabekyan, E. Kolganova, R. Jolos, D. A. Sazonov

引用次数: 0