A New Study of the Polarized Parton Densities in the Nucleon.pdf

A new study of the polarized parton densities in the nucleon 9 9 9 Elliot Leader 1 Birkbeck College, University of London y a Malet Street, London WC1E 7HX, England M E-mail: e.leader@physics.bbk.ac.uk 7 2 Aleksander V. Sidorov 1 v Bogoliubov Theoretical Laboratory 2 Joint Institute for Nuclear Research 1 5 41980 Dubna, Russia 5 0 E-mail: sidorov@thsun1.jinr.ru 9 9 / Dimiter B. Stamenov h p- Institute for Nuclear Research and Nuclear Energy p e Bulgarian Academy of Sciences h blvd. Tsarigradsko Chaussee 72, Sofia 1784, Bulgaria : v i E-mail:stamenov@inrne.bas.bg X r a Abstract We present a new next-to-leading order QCD analysis of the world data on inclusive polarized deep inelastic lepton-nucleon scattering adding to the old set of data the final SMC results, the HERMES proton and very recent SLAC/E155 deuteron data. We find an excellent fit to the data and present results for the polarized parton densities in different factorization schemes. These results are in a good agreement with what follows from the theory. We have also found that the main effect of the newly incorporated data is a better determination of the polarized gluon density. Recently [1, 2] we carried out a next-to-leading order (NLO) QCD analysis of the world data on polarized inclusive dee