Abstract
Jets are manifestation of hard scatterings of partons and its understanding in pp involves the partondistribution functions, the QCD-hard scattering processes and the long distance fragmentation phenomena.Therefore, jets can be used to study the parton level kinematics. Intrinsic transverse momentumof partons and the subsequent gluon radiations prior to hard scatterings [1], give rise to acoplanarityof dijets, depending on the Q2 of hard scatterings and the center of mass energy of collisions. Multiplescatterings of the hard scattered partons in cold nuclear matter may incorporate a modi cation of jetstructure.Two quantities commonly used to characterize the properties of jets are (i) jt, the transverse momentumof the jet fragments relative to the jet axis and (ii) kt, the transverse component of the momentumof the hard scattered partons. A measurement of the jet parameters, phj2t i and phk2t i [2] at STAR inpp collisions at ps = 62.4, 200 and 500 GeV using di-hadron correlation techniques is presented in widekinematics rage. 0 (Et = 6.5 to 18.5 GeV) and charged tracks (pt = 3.0-8.5 GeV/c) are used as triggerparticles in this analysis. A comparison of the jet parameters for pp and dAu (at various centralities) atps = 200 GeV will be presented.References[1] R.P Feynman, R.D. Field, and G.C. Fox, Phys. Rev. D18 3320(1978).[2] S.S. Adler et al., Phys. Rev. D74 072002(2006).
