Measurement of the Polarization of the Ү(1S) and Ү(2S) States in pp Collisions at √s = 1.96 TeV

Authors

V. M. Abazov, Joint Institute for Nuclear Research, Dubna, Russia
Kenneth A. Bloom, University of Nebraska-LincolnFollow
Gregory Snow, University of Nebraska-LincolnFollow
D0 Collaboration

Date of this Version

10-31-2008

Comments

Published in PHYSICAL REVIEW LETTERS 101, 182004 (2008). Copyright © 2008 The American Physical Society. Used by permission.

Abstract

We present a study of the polarization of the Ү(1S) and Ү(2S) states using a 1.3 fb^-1 data sample collected by the D0 experiment in 2002–2006 during run II of the Fermilab Tevatron Collider. We measure the polarization parameter α = (σ_T - 2σ_L), where σ_T and σ_L are the transversely and longitudinally polarized components of the production cross section, as a function of the transverse momentum (p_T^Ү) for the Ү(1S) and Ү(2S). Significant p_T^Ү-dependent longitudinal polarization is observed for the Ү(1S). A comparison with theoretical models is presented.