Fixed t subtracted dispersion relations for Compton Scattering off the nucleon
Fixed t subtracted dispersion relations for Compton Scattering off the nucleon
复制标题
修复了核子康普顿散射的 t 减去色散关系
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
M. Vanderhaeghen
中科院分区：
文献类型：
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作者：
D. Drechsel;B. Pasquini;M. Gorchtein;M. Vanderhaeghen
我们提出了能量为$E_gamma leq$ 500 MeV的核子康普顿散射的固定-$t$减去色散关系，作为一种以最小的模型依赖性提取核子极化率的形式。减去的色散积分主要由$s$通道$gamma N o o γ N$和$t$通道$gamma o o o N ar N$中的$pi pi$中间态饱和。对于子过程$gamma gamma o pi pi$，我们构造了一个统一幅度并找到了对可用数据的良好描述。我们用消色散关系给出了康普顿散射的结果，并展示了标量极化率差$alpha - eta$和反向自旋极化率$gamma_pi$的灵敏度，它们直接作为拟合参数输入到目前的形式中。
We present fixed-$t$ subtracted dispersion relations for Compton scattering off the nucleon at energies $E_gamma leq$ 500 MeV, as a formalism to extract the nucleon polarizabilities with a minimum of model dependence. The subtracted dispersion integrals are mainly saturated by $pi N$ intermediate states in the $s$-channel $gamma N o pi N o gamma N$ and $pi pi$ intermediate states in the $t$-channel $gamma gamma o pi pi o N ar N$. For the subprocess $gamma gamma o pi pi$, we construct a unitarized amplitude and find a good description of the available data. We show results for Compton scattering using the subtracted dispersion relations and display the sensitivity on the scalar polarizability difference $alpha - eta$ and the backward spin polarizability $gamma_pi$, which enter directly as fit parameters in the present formalism.