he bound-state level structures of the $^{16}_Λ$O and $^{15}_Λ$N hypernuclei were studied by $γ$-ray spectroscopy using a germanium detector array (Hyperball) via the $^{16}$O ($K^-, π^- γ$) reaction. A level scheme for $^{16}_Λ$O was determined from the observation of three $γ$-ray transitions from the doublet of states ($2^-$,$1^-$) at $\sim 6.7$ MeV to the ground-state doublet ($1^-$,$0^-$). The $^{15}_Λ$N hypernuclei were produced via proton emission from unbound states in $^{16}_Λ$O . Three $γ$ -rays were observed and the lifetime of the $1/2^+;1$ state in $^{15}_Λ$N was measured by the Doppler shift attenuation method. By comparing the experimental results with shell-model calculations, the spin-dependence of the $ΛN$ interaction is discussed. In particular, the measured $^{16}_Λ$O ground-state doublet spacing of 26.4 $\pm$ 1.6 $\pm$ 0.5 keV determines a small but nonzero strength of the $ΛN$ tensor interaction.
We propose a novel method for producing very-neutron-rich hypernuclei and corresponding resonance states by employing charge-exchange reactions via pp($^{12}$C, $^{12}$N $K^+$)n$Λ$ with single-charge-exchange and ppp($^{9}$Be, $^{9}$C $K^+$)nn$Λ$ with double-charge-exchange, both of which produce $ΛK^+$ in a target nucleus. The feasibility of producing very-neutron-rich hypernuclei using the proposed method was analysed by applying an ultra-relativistic quantum molecular dynamics model to a $^6$Li+$^{12}$C reaction at 2 $A$ GeV. The yields of very-neutron-rich hypernuclei, signal-to-background…
Mesonic and nonmesonic weak decay widths of medium-heavy lambda hypernuclei
我们测量了由（π ~+，K ~+）反应产生的12_Lambda_C，28_Lambda_Si和Lambda_Fe超核在弱衰变中发射的π介子和质子的能谱。提取了π介子衰变（λ-> p + π-）和非介子衰变（λ + N -> N + N）的衰变宽度。本文的结果首次证实了由于核介质中π介子波函数的畸变而导致介子衰变宽度的增加。通过测量质子能谱与计算质子能谱的直接比较，计算了中子与质子引起的非介子衰变宽度之比γ_n（Lambda + n -> n + n）/γ_p（Lambda + p -> n + p）。目前还没有一种理论计算方法能同时解释现有数据中的非介子衰变宽度和γ_n/γ_p比值。
Multifragmentation reactions are dominating processes for the decomposition of highly excited nuclei leading to the fragment production in heavy-ion collisions. At high energy reactions strange particles are abundantly produced. We present a novel development of the Statistical multifragmentation model (SMM) as its generalization for the hyper-matter which is formed after the hyperon capture. In this way, it is possible to describe its disintegration into normal and hyper-nuclei. Some properties of hyper-nuclei and their binding energies can be determined from the comparison of the isotope yie…
Hypernucleus production in p+Au reactions at the FAIR facility
Naresuan University（纳瑞宣大学）；Suranaree University of Technology（素拉那里理工学院）；GSI Helmholtzzentrum für Schwerionenforschung GmbH（GSI亥姆霍兹重离子研究中心有限公司）；Frankfurt Institute for Advanced Studies（法兰克福高等研究院）；Goethe-Universität Frankfurt（法兰克福歌德大学）
We propose a new experiment for decay pion spectroscopy of light hypernuclei at electron- and proton-beam facilities, using the recoil distance technique for separation of produced hypernuclei and a magnetic spectrometer for precise measurement of the decay pion momentum. Low-pressure MWPCs are advocated for low-energy recoil detection as they provide position and time information and are highly insensitive to gamma-ray and electron background. The position and timing characteristics of such a recoil detector were studied using ~5 MeV α-particles. By using the present proposed approach the rat…
Investigation of alpha-induced reactions on 127I for the astrophysical gamma process
为了给天体物理γ过程的模拟提供截面数据，用活化技术研究了α-诱发的~（127）I反应。精确测量了536.1keV γ跃迁的相对强度，其不确定度由13%降低到4%。通过测量特征X射线的产额，首次确定了127 I（α，γ）~（131）Cs反应的截面接近天体物理相关的能量区域，能量为9.50 <Ec. m。< 15.15由于反应模型的改进，$ MeV. The 127I(alpha,n)130Cs reaction was studied in the range 9.62 < Ec.m. < 15.15 MeV by measuring the yield of the 536.1 keV gamma-ray and at the lower part of this energy range by counting the characteristic X-rays. A comparison of the resulting cross sections to predictions of statistical model calculations confirmed the predictions of the astrophysically relevant averaged alpha width. Nevertheless, the newly derived stell…
Differential cross sections for the reactions gamma p-> p eta and gamma p -> p eta-prime
高统计微分截面的反应γ p -> p eta和γ p -> p eta-素数已被测量使用CLAS在杰斐逊实验室的质心能量从近阈值高达2.84 GeV。eta-prime的结果是迄今为止最精确的，并提供了最大的能量和角度覆盖范围。eta测量将世界上大角度结果的能量范围扩展了约300 MeV。这些新的数据，特别是η素数的测量，可能有助于限制正在进行的分析，以寻找新的重子共振态。
$Ξ^-$ hyperon and hypernuclear production in the $(K^-,K^+)$ reaction on nucleon and nuclei in a field theoretical model
在协变的有效拉格朗日模型下，我们分别研究了质子和核靶上的$(K^-,K^+)$反应中级联超子（$Ξ$）和束缚$Ξ^-$超核的产生。$K^+Ξ^-$产生顶点是由$K^-$介子与入射通道中的自由或束缚质子初始碰撞中$Λ$和$Σ$共振态的激发、传播和衰变来描述的。共振顶点的参数取自以前的研究和SU（3）对称性的考虑。该模型能够很好地描述$p(K^-, K^+)Ξ^-$反应的总截面和微分截面。同样的机制被用来描述超核生产反应$^{12}$ C $(K^-,K^+)^{12}{/!/!/!_{/Xi^-}}$ Be和$^{28}$ Si $(K^-,K^+)^{28}{/!/!/!_{Ξ^-}}$ Mg，其中$Ξ$束缚态旋量计算内的唯象模型已被采用。元核和超核产生截面都主要由$Λ$（1520）中间共振态的贡献所决定。发现形成$Ξ$超核的$0^\circ$微分截面对束流动量的依赖性与以前在冲量近似模型计算中所观察到的有显著的不同
In the present work, we report our in depth study of 12C(p,p'gamma)12C reaction both experimentally and theoretically with proton beam energy ranging from 8 MeV to 22 MeV. The angular distributions were measured at six different angles. We discuss the gamma angular distributions, total cross sections values for 4.438, 9.64, 12.7 and 15.1 MeV states. We also describe the theoretical interpretation of our measurements using optical model analysis. We also report the branching ratios from our measurements. For the first time, we have measured the the cross section and branching ratio for the 9.64…
Differential cross sections and spin density matrix elements for the reaction gamma p -> p omega
高统计微分截面和自旋密度矩阵元素的反应γ p -> p Ω已被测量使用CLAS在杰斐逊实验室的质心（CM）的能量从阈值到2.84 GeV。结果报告在112 10兆电子伏宽CM能量箱，每个细分为cos（θ CM）箱的宽度为0.1。这些是迄今为止最精确和最广泛的欧米茄光合作用测量。一些突出的结构在数据中清晰可见。由于早期测量的统计数据有限，其中许多以前没有观察到。
The missing-mass spectroscopy of $Λ$ hypernuclei via the $(e,e^{\prime}K^{+})$ reaction has been developed through experiments at JLab Halls A and C in the last two decades. For the latest experiment, E05-115 in Hall C, we developed a new spectrometer system consisting of the HKS and HES; resulting in the best energy resolution ($E_Λ \simeq0.5$-MeV FWHM) and $B_Λ$ accuracy ($B_Λ\leq0.2$ MeV) in $Λ$-hypernuclear reaction spectroscopy. This paper describes the characteristics of the $(e,e^{\prime}K^{+})$ reaction compared to other reactions and experimental methods. In addition, the experimental…
In a recent work, the cross section measurement of the 64Zn(p,alpha)61Cu reaction was used to prove that the standard alpha-nucleus optical potentials used in astrophysical network calculation fail to reproduce the experimental data at energies relevant for heavy element nucleosynthesis. In the present paper the analysis of the obtained experimental data is continued by comparing the results with the predictions using different parameters. It is shown that the recently suggested modification of the standard optical potential leads to a better description of the data.
