Spin alignment of leading K*(892)degrees mesons in hadronic Z degrees decays

Helicity density matrix elements for inclusive K*(892)(0) mesons from hadronic Z(0) decays have been measured over the full range of K*(0) momentum using data taken with the OPAL experiment at LEP. A preference for occupation of the helicity zero state is observed at all scaled momentum x(p) values above 0.3, with the matrix element rho(00) rising to 0.66+/-0.11 for x(p)>0.7. The values of the real part of the off-diagonal element rho(1-1) are negative at large x(p), with a weighted average value of -0.09+/-0.03 for x(p)>0.3, in agreement with new theoretical predictions based on Standard Model parameters and coherent fragmentation of the q (q) over bar system from the Z(0) decay. All other helicity density matrix elements measured are consistent with zero over the entire x(p) range. The K*(0) fragmentation function has also been measured and the total rate determined to be 0.74+/-0.02+/-0.02 K*(892)(0) mesons per hadronic Z(0) decay. (C) 1997 Published by Elsevier Science B.V