Network of Nuclear Process in Astrophysics

Network of Nuclear Process1. Introductionin AstrophysicsY.S. ChenChina Institute of Atomic Energy, Beijing, ChinaPresentation at group meeting,Wendushuicheng, August 12-13 , 2010.2. Theory of capture reaction3. Theory of -decay4. Network equation and nuclear data base5. Our task

Introduction

Why nuclear astrophysics?Nuclear scientists have tools that enable studies of thecosmos that are impossible with any telescope !We can use accelerators to recreate – and - measurethe nuclear reactions that power the stars &create elements of our life and world.

Relevant nuclei of each frontier region

Theory of Capture Reaction

Useful Theory for Cross SectionANC methodSpectroscopic factor

Transition Amplitude forT r r BpA ( , , r)| O(r)| Bprelative between B and pB + p A + B( ) ( ) Bpp( )( r)integrate over T IABp ( r)| O(r)| ( )( r)the overlap integralIABp( r) ( ) ( ) | ( , , r)BBppABp

For peripheral reaction (p,)Ifj I( r) Cj IW, 1/2(2r)/ r (r R N)ffffC fj fIis the ANCW (2, f 1/2r)is the Whittaker function, 2EB/ for bound stateThe Asymptotic Normalization Constant (ANC):the amplitude ofthe tail of the overlap integral

For peripheral transfer reaction:B(d,n)Atwo virtual captures:B + p An + p dtwo ANC’s :AC BpanddC npdd ( CABplAjA2bBplA)j2A( Cbdnpl2npl jdddjd)2DWBAl j l jAAdd21( C d np) 0.76 fm known valueA 2d( CBp)can be obtained from ( )expd

For non-peripheral reaction (n,)Standard approach (Spectroscopic factor)IABplAjA( r)( SlAjA)1/ 2RnAlAjA( r)Idnpldjd( r)( Sldjd)1/ 2Rndldjd( r)dd SBplAjASnpldjdDWBAl j l jAAddSpectroscopic factor S is very sensitive to singleparticle parameters in DW. But ANC is not so sensitive.

-Decay Theory

-decay theory for deformed heavy nucleiGT-forcesparticle-holeparticle-particle

Gamow-Teller transitions betweenthe excited statesE(I) (MeV)1.61.41.21.00.80.60.40.20.08 +Exp.7 +PSM6 +5 +4 +3 +1 +0 +2 + 164 Ho6 +4 +2 +0 2 4 6 8Spin ()8 +164 DyLog ftB(GT)0.30.20.10.05.55.04.50 2 4 6 8Spin ()0 2 4 6 8Spin ()Z.C. Gao et al., Phys. Rev. C74, 054303 (2006)

• The Projected Shell Model has been applied tocalculate the GT transitions for heavy,deformed nuclei• The testing calculation of the e-capture164Ho(Z=67) 164 Dy(Z=66) is in a goodagreement with data.

Network equationand nuclear data base

The reaction network--- a set of differential equationsdYdtij,k , lNjij,k , lNij Yj2 Nj2Aj,kN Vij,kNjkl,iYAjY VkYljk,iYjYkYini/NAThe nuclear abundanceN AniN iAvagadro constant numberThe densityThe number density of species ‘i’Positive or negative numbers to specify how many particles ofspecies i are created or destroyed in the reaction

The set of differential equations ruling BBNRRnnBHB 3H8G N3 3H( p)B e

],,,,,[),()( f e f effffItpfppHtxxeelkjijklABlkjilkjkjijkABkjikjjjjijiY Y YVNNY YVNNYNdtdY,22,,,,,,,),( eeeeiiiBTmLnnXZn

Reaction chain 8 Li(n,) 9 Li(,n) 12 B() 12 CReaction flux

BBN calculation ( 侯 素 青 )

The effect of 8 Li(n,) 9 Li(,n) 12 B() 12 C

Our tasks

本 项 目 以 核 物 理 实 验 及 天 文 观 测 为 主 , 理 论 同 实 验 密 切 结 合 ;以 国 内 大 型 科 学 工 程 的 实 验 设 备 为 基 础 , 并 利 用 国 际 先 进 实 验 设备 。理 论 紧 密 结 合 实 验 , 着 重 为 本 项 目 的 实 验 数 据 提 升 科 学 意 义 ,为 进 一 步 实 验 提 供 建 议 。理 论 在 同 核 物 理 实 验 和 天 文 观 测 的 比 较 中 和 需 求 中 发 展 。重 视 核 天 体 物 理 理 论 和 计 算 方 法 的 新 发 展 。

网 络 方 程 数 据 库 建 立 和 更 新BBNrp-processr-process发 展 核 天 体 物 理 理 论Explosive events:Big Bang (light nuclei)x-ray burst (rp-nuclei, proton rich)Supernova (r-nuclei, neutron rich)发 展 核 理 论Spectroscopic Factor-decay

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