π− p → η() π− p in the double-Regge region

Abstract

The production of η(′)π pairs constitutes one of the golden channels to search for hybrid exotics, with explicit gluonic degrees of freedom. Understanding the dynamics and backgrounds associated to η(′)π production above the resonance region is required to impose additional constraints to the resonance extraction. We consider the reaction π−p→η(′)π−p measured by COMPASS. We show that the data in 2.4<mη(′)π<3.0GeV can be described by amplitudes based on double-Regge exchanges. The angular distribution of the meson pairs, in particular in the η′π channel, can be attributed to flavor singlet exchanges, suggesting the presence of a large gluon content that couples strongly to the produced mesons.