Northwestern University, Evanston, Illinois 60208, USA.
Phys Rev Lett. 2013 Jul 12;111(2):022501. doi: 10.1103/PhysRevLett.111.022501. Epub 2013 Jul 11.
We have isolated ν(μ) charged-current quasielastic (QE) interactions occurring in the segmented scintillator tracking region of the MINERvA detector running in the NuMI neutrino beam at Fermilab. We measure the flux-averaged differential cross section, dσ/dQ², and compare to several theoretical models of QE scattering. Good agreement is obtained with a model where the nucleon axial mass, M(A), is set to 0.99 GeV/c² but the nucleon vector form factors are modified to account for the observed enhancement, relative to the free nucleon case, of the cross section for the exchange of transversely polarized photons in electron-nucleus scattering. Our data at higher Q² favor this interpretation over an alternative in which the axial mass is increased.
我们已经分离出在 MINERvA 探测器分段闪烁体跟踪区中发生的 ν(μ)带电电流准弹性(QE)相互作用，该探测器在费米实验室的 NuMI 中微子束中运行。我们测量了通量平均微分截面 dσ/dQ²，并与几个 QE 散射的理论模型进行了比较。与一个模型的结果吻合得很好，该模型中设定核子的轴质量 M(A)为 0.99GeV/c²，但核子矢量形状因子被修改，以考虑到在电子-核子散射中交换横向极化光子的截面相对于自由核子情况的增强。我们在更高 Q²处的数据支持这种解释，而不是轴质量增加的替代解释。
