Is the fragmentation of charm quarks into D mesons described by heavy quark effective theory?

摘要

Heavy quark effective theory predicts that produced charm quarks have the same probability to fragment into any of the four D mesons with orbital angular momentum L = 0: the singlet D state and the triplet D* states. This would imply P-V(D*, D) = 3/4, where P-V is the ratio between directly produced L = 0 vector states (D*) and all L = 0 (D and D*) states. Experimental data collected in several different collision systems (e(+)e(-), hadro-production, photo-production, etc.) and over a broad range of collision energies, show that PV (D*, D) = 0.594 +/- 0.010. From this observation, it follows that "naive spin counting" does not apply to charm production, implying a revision of charm production calculations where this assumption is made. (c) 2006 Elsevier B.V. All rights reserved.