QUARK ENERGY LOSS MEASUREMENT WITH THE CLAS DETECTOR

Abstract

In this analysis, we studied quark energy loss for positive pions produced in DIS events. The analysis used data from experiments carried out during the run period EG2 in Hall B of Jefferson Lab, Virginia. The experiments used a 5.014 GeV electron beam and studied the nuclear targets deuterium, carbon, iron and lead. This phenomenon has been studied indirectly in various types of scattering experiments such as heavy-ion collisions, DIS, among others, measuring different kinds of hadrons, such as pions and kaons. By looking at the production of ⇡+ from two different targets we can obtain information about quark energy loss by comparing the curves of the energy spectra. Assuming that the energy distributions from the different targets have approximately the same behaviour, the goal of the study is to measure the size of the horizontal shift between the distributions that would correspond to a shift in quark energy. To extract quark energy loss, the method proposed is to shift the energy spectrum from the solid target by some chosen amount and compare this new distribution with the original energy spectrum from the deuterium target. To compare the curves the Kolmogorov-Smirnov statistical test was used, that gives the probability that both curves follow the same underlying distribution. If the described steps are repeated for a sufficient number of different shifts in energy a probability curve is obtained and the average energy loss can be estimated.