Speaker
Prof.
Shunzo Kumano
(KEK)
Description
I will review nuclear effects on neutrino-nucleus deeply inelastic scattering (DIS) and discuss the nuclear parton distributions functions (NPDFs). Due to the weak interaction, heavy nuclear target is needed to get high accuracy of the measurements. The nuclear effects on the structure function must be taken into account. These effects are already known by charged lepton-nucleus DIS experiments. In the ratio of the structure functions obtained by nucleus and deuteron targets; $R^A(x)=F_2^A(x)/F_2^D(x)$, these effects show the following behavior: $R^A(x)<1$ for $x<0.07$ (shadowing effect) $R^A(x)>1$ for $0.1<x<0.3$ (anti-shadowing effect) $R^A(x)<1$ for $0.3<x<0.8$ (EMC effect) $R^A(x)>1$ for $0.8<x$ (Fermi motion effect) where $x$ is the Bjorken-$x$. These are interpreted as the effects of parton-nucleon multiple scattering,
nucleon binding and internal motion in the nucleus. Models explained each effect are proposed, however these effect must be comprehensively treated in theoretical prediction for the measurements using nucleus targets. As a way of involving these effects in a similar manner, nuclear parton distribution functions (NPDFs) are investigated. These nuclear effects are contained in the parton distributions, and these distributions are determined by using experimental data with nucleus targets. By using the NPDFs, nuclear effect on the measurements can be discussed quantitatively. In practice, extraction of NPDFs is performed by several analysis groups. I will discuss the NPDFs of these analyses.
Author
Dr
Masanori Hirai
(Tokyo University of Science)
