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Quark fragmentation and off-diagonal helicity density matrix elements for vector meson production

M. Anselmino, M. Bertini, F. Murgia, P. Quintairos

hep-pharXiv:hep-ph/9810226

Abstract

As confirmed by some recent LEP data on phi, K* and D*0 production, final state interactions in quark fragmentation may give origin to non-zero values of the off-diagonal element rho1,-1 of the helicity density matrix of vector mesons produced in e+ e- annihilations: we give estimates for rho1,-1 of vector mesons with a large xE and collinear with the parent jet, relating its size and sign to the associated hard constituent dynamics. We mention possible non-zero values of rho1,-1 in several other processes.

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