Spin effects in heavy quarkonia production

por Oleg Teryaev (Inst. f. Theor. Phys., Uni-Regensburgand Bogoliubov Lab. THeor. Phys., JINR, Du)

martes 27 feb. 2001 12:30 → 13:30 Europe/Madrid

Sala Seminarios (Dpto. de Física Teórica (UVEG))

Various initial and final state spin asymmetries in lepto- and hadroproduction of heavy quarkonia are examined. The single spin asymmetries in leproproduction are absent at Born level and are very sensitive to the details of production mechanism. The double spin asymmetries receive significant enhancement from the colour octet contribution. The $k_\perp$ factorization approach at small $x$ provides the complementary contribution to the standard collinear factorization and leads to a very good description of the open beauty production. It naturally explains the large cross-section for the production of $\Chi_1$ state and absence of large transverse polarization of direct $J/\Psi$. The discovery potential for the measurement of the polarized gluon density is discussed.