The role of spin in fragmentation production j/ψ(1S) and ϒ(1S)

In this work we calculate the process-independent fragmentation functions for a heavy quark Q to fragment into vector and pseudoscalar heavy quarkonium to leading order perturbative QCD. We investigate the role of the spin orientation of the initial and final heavy quarks on the fragmentation functions. In the special case, we calculate fragmentation functions by using average over spin of initial state heavy quark and sum over spin of final states. The universal fragmentation probabilities for the c→j/ψ(1S) and b→ϒ(1S) are about 10−4 and 10−5, respectively. Moreover, the spin dependent observables such as V/(V+P) and V/P ratios are estimated.