Relativistic model of 2p-2h meson exchange currents in (anti)neutrino scattering
Relativistic model of 2p-2h meson exchange currents in (anti)neutrino scattering
复制标题
（反）中微子散射中 2p-2h 介子交换电流的相对论模型
DOI：
10.1088/1361-6471/aa6a06
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
T. W. Donnelly
中科院分区：
文献类型：
--
作者：
I. Simó;J. E. Amaro;M. Barbaro;A. Pace;J. A. Caballero;T. W. Donnelly
我们发展了一个中微子-核相互作用的相对论性带电介子交换流模型。二体流是海鸥、飞行中的π介子、π介子-极和$\Delta$-极算子的和。这些算子是由非线性$\sigma$-模型中核子的弱π介子产生振幅以及$\Delta（1232）$共振的弱激发及其随后的衰变得到的。利用这些电流，我们计算了相对论费米气体模型中$（\nu_l，l^-）$和$（\overline{\nu}_l，l^+）$反应的5个2 p-2 h响应函数。总电流是矢量和轴向两体电流之和。矢量流与有助于电子散射的电磁MEC算子有关。这使得人们可以通过与De Pace的结果进行比较来检查我们的模型。303.第303章一夜情因此，我们的模型是一个自然的扩展，该模型的弱扇区的轴向MEC运营商。的方法的几个成分上的响应函数的依赖性进行了分析。具体来说，我们讨论相对论效应，量化的直接交换干扰的大小，和相对重要性的轴向与矢量电流。
We develop a model of relativistic, charged meson-exchange currents (MEC) for neutrino-nucleus interactions. The two-body current is the sum of seagull, pion-in-flight, pion-pole and $\Delta$-pole operators. These operators are obtained from the weak pion-production amplitudes for the nucleon derived in the non-linear $\sigma$-model together with weak excitation of the $\Delta(1232)$ resonance and its subsequent decay into $N\pi$. With these currents we compute the five 2p-2h response functions contributing to $(\nu_l,l^-)$ and $(\overline{\nu}_l,l^+)$ reactions in the relativistic Fermi gas model. The total current is the sum of vector and axial two-body currents. The vector current is related to the electromagnetic MEC operator that contributes to electron scattering. This allows one to check our model by comparison with the results of De Pace {\em et al.,} Nuclear Physics A 726 (2003) 303. Thus our model is a natural extension of that model to the weak sector with the addition of the axial MEC operator. The dependences of the response functions on several ingredients of the approach are analyzed. Specifically we discuss relativistic effects, quantify the size of the direct-exchange interferences, and the relative importance of the axial versus vector current.