Physical Review C最新文献_第7页

New approach to large-scale nuclear structure calculations 大规模核结构计算的新方法

IF 3.1 2区物理与天体物理

Physical Review C Pub Date : 2001-01-22 DOI: 10.1103/PhysRevC.63.061303

Jorge Dukelsky, S. Pittel

引用次数: 1

Measurement of neutron capture on 50 Ti at thermonuclear energies. 热核能50ti上中子俘获的测量。

IF 3.1 2区物理与天体物理

Physical Review C Pub Date : 1999-07-28 DOI: 10.1103/PHYSREVC.60.054613

P. Sedyshev, P. Mohr, P. Mohr, H. Beer, H. Oberhummer, Yu. P. Popov, W. Rochow

{"title":"Measurement of neutron capture on 50 Ti at thermonuclear energies.","authors":"P. Sedyshev, P. Mohr, P. Mohr, H. Beer, H. Oberhummer, Yu. P. Popov, W. Rochow","doi":"10.1103/PHYSREVC.60.054613","DOIUrl":"https://doi.org/10.1103/PHYSREVC.60.054613","url":null,"abstract":"At the Karlsruhe and T\"ubingen 3.75 MV Van de Graaff accelerators the thermonuclear ${}^{50}mathrm{Ti}(n,ensuremath{gamma}{)}^{51}mathrm{Ti}(5.8mathrm{min})$ cross section was measured by the fast cyclic activation technique via the 320.852 and 928.65 keV $ensuremath{gamma}$-ray lines of the ${}^{51}mathrm{Ti}$ decay. Metallic Ti samples of natural isotopic composition and samples of ${mathrm{TiO}}_{2}$ enriched in ${}^{50}mathrm{Ti}$ by 67.53% were irradiated between two gold foils which served as capture standards. The capture cross section was measured at the neutron energies of 25, 30, 52, and 145 keV, respectively. The direct capture cross section was determined to be $0.387ifmmodepmelsetextpmfi{}0.011mathrm{mb}$ at 30 keV. We found evidence for a bound state s-wave resonance with an estimated radiative width of 0.34 eV which destructively interferes with direct capture. The strength of a suggested s-wave resonance at 146.8 keV was determined. The present data served to calculate, in addition to the directly measured Maxwellian averaged capture cross sections at 25 and 52 keV, an improved stellar ${}^{50}mathrm{Ti}(n,ensuremath{gamma}{)}^{51}mathrm{Ti}$ rate in the thermonuclear energy region from 1 to 250 keV. The new stellar rate leads at low temperatures to much higher values than the previously recommended rate; e.g., at $kT=8mathrm{keV}$ the increase amounts to about 50%. The new reaction rate therefore reduces the abundance of ${}^{50}mathrm{Ti}$ due to s processing in asymptotic giant branch stars.","PeriodicalId":48700,"journal":{"name":"Physical Review C","volume":"205 1","pages":"054613"},"PeriodicalIF":3.1,"publicationDate":"1999-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75561575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Stellar neutron capture cross sections of the Nd isotopes Nd同位素的恒星中子俘获截面

IF 3.1 2区物理与天体物理

Physical Review C Pub Date : 1998-01-01 DOI: 10.1103/PHYSREVC.57.391

K. Wisshak, F. Voss, F. Käppeler, L. Kazakov, G. Reffo

{"title":"Stellar neutron capture cross sections of the Nd isotopes","authors":"K. Wisshak, F. Voss, F. Käppeler, L. Kazakov, G. Reffo","doi":"10.1103/PHYSREVC.57.391","DOIUrl":"https://doi.org/10.1103/PHYSREVC.57.391","url":null,"abstract":"The neutron capture cross sections of {sup 142}Nd, {sup 143}Nd, {sup 144}Nd, {sup 145}Nd, {sup 146}Nd, and {sup 148}Nd have been measured in the energy range from 3 to 225 keV at the Karlsruhe 3.75 MV Van de Graaff accelerator. Neutrons were produced via the {sup 7}Li(p,n){sup 7}Be reaction by bombarding metallic Li targets with a pulsed proton beam. Capture events were registered with the Karlsruhe 4{pi} Barium Fluoride Detector. The cross sections were determined relative to the gold standard. The experiment was difficult due to the small cross sections of the even isotopes at or near the magic neutron number N=82, and also since the isotopic enrichment of some samples was comparably low. The necessary corrections for capture of scattered neutrons and for isotopic impurities could be determined reliably thanks to the high efficiency and the spectroscopic quality of the BaF{sub 2} detector, resulting in a consistent set of (n,{gamma}) cross sections for the six stable neodymium isotopes involved in the s process with typical uncertainties of 1.5{endash}2{percent}. From these data, Maxwellian averaged cross sections were calculated between kT=10 and 100 keV. The astrophysical implications of these results were investigated in an s-process analysis, which deals with the rolemore » of the s-only isotope {sup 142}Nd for the N{sub s}{l_angle}{sigma}{r_angle} systematics near the magic neutron number N=82, the decomposition of the Nd abundances into the respective r-, s-, and p-process components, and the interpretation of isotopic anomalies in meteoritic material. {copyright} {ital 1998} {ital The American Physical Society}« less","PeriodicalId":48700,"journal":{"name":"Physical Review C","volume":"43 1","pages":"391-408"},"PeriodicalIF":3.1,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88921688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Off-shell effects in the electromagnetic production of strangeness 电磁奇异性产生中的脱壳效应

IF 3.1 2区物理与天体物理

Physical Review C Pub Date : 1997-12-10 DOI: 10.1103/PhysRevC.58.75

T. Mizutani, C. Fayard, G. Lamot, B. Saghai

引用次数: 61

π N →η N and η N →η N partial-wave T matrices in a coupled, three-channel model 耦合三通道模型中的π N→η N和η N→η N偏波T矩阵

IF 3.1 2区物理与天体物理

Physical Review C Pub Date : 1995-01-16 DOI: 10.1103/PhysRevC.51.2310 10.1103/PhysRevC.57.1004

M. Batinic, I. Slaus, A. Švarc, B. Nefkens

{"title":"π N →η N and η N →η N partial-wave T matrices in a coupled, three-channel model","authors":"M. Batinic, I. Slaus, A. Švarc, B. Nefkens","doi":"10.1103/PhysRevC.51.2310 10.1103/PhysRevC.57.1004","DOIUrl":"https://doi.org/10.1103/PhysRevC.51.2310 10.1103/PhysRevC.57.1004","url":null,"abstract":"The ensuremath{pi}Nensuremath{rightarrow}ensuremath{eta}N and ensuremath{eta}Nensuremath{rightarrow}ensuremath{eta}N partial-wave T matrices for the eight lowest partial waves have been obtained in a three-coupled-channel model with unitarity manifestly imposed. The two physical channels are ensuremath{pi}N and ensuremath{eta}N, and the third channel, ensuremath{pi}ensuremath{pi}N is an effective, but unphysical two-body channel which represents all remaining processes. The ensuremath{pi}N elastic phase shifts and the weighted data base of the ensuremath{pi}Nensuremath{rightarrow}ensuremath{eta}N total and differential cross sections are chosen as the input for the fitting procedure. A model containing a single resonance in each of the three partial waves that dominates the ensuremath{eta} production at lower energies is compared with previous analyses, based on similar assumptions. A multiresonance coupled-channel model is introduced which significantly improves the agreement with all input data. Our results are compared with a complementary multiresonance coupled-channel analysis that is constrained with elastic and continuum production channels. The inclusion of the fourth ${mathit{P}}_{11}$ resonance in the 1440char21{}2200 MeV region further improves the agreement between the analysis and the data.","PeriodicalId":48700,"journal":{"name":"Physical Review C","volume":"3 1","pages":"2310"},"PeriodicalIF":3.1,"publicationDate":"1995-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88815479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 56

Suppression of dilepton production in hot hadronic matter 热强子物质双轻子产生的抑制

IF 3.1 2区物理与天体物理

Physical Review C Pub Date : 1994-12-16 DOI: 10.1103/PhysRevC.52.476

Chung-sik Song, Su Houng Lee, C. Ko

引用次数: 3