Production of spin-3 mesons in diffractive DIS

Abstract

We calculate the amplitudes of J P C = 3 −− meson production in diffractive DIS within the k t -factorization approach, with a particular attention paid to the ρ 3 (1690) meson. We find that at all Q 2 the ρ 3 (1690) production cross section is 2-5 times smaller than the ρ(1700) production cross section, which is assumed to be a pure D-wave state. Studying σ L and σ T separately, we observe domination of ρ 3 in σ L and domination of ρ(1700) in σ T and offer an explanation of this behavior in simple terms. We also find very strong contributions -sometimes even domination -of the s-channel helicity violating amplitudes. The typical color dipole sizes probed in ρ 3 production are shown to be larger than those in the ground state ρ production, and the energy dependence of ρ 3 cross section turns out to be much flatter than the ρ production cross section. All the conclusions about the relative behavior of ρ 3 (1690) and ρ(1700) mesons are numerically stable against variations of input parameters.