Discussion

Abstract

In this chapter, we discuss constraint on the gluon polarization in a polarized proton from the obtained double-spin asymmetries. We estimated double-spin asymmetries under various gluon polarizations using cross sections of charm quark production expected by an LO pQCD calculation and pythia simulations. Using the estimated asymmetries, constraints were obtained based on a ${\varvec{\chi }}^{2}$ method. As the result, the constraint of the gluon polarization was found to be $|\Delta g/g|^{2}<(3.0_{-0.2}^{+0.4}\mathrm{{(mass)}}_{-0.3}^{+0.5}\mathrm{{(scale)}})\times 10^{-2}$($1\sigma$) at $\left\langle \log _{10}x\right\rangle =-1.6^{+0.5}_{-0.4}$ and $\mu =1.4$ GeV.