Observation of exotic meson production in the reaction pi- p --> eta'pi- p at 18 GeV/c

E I Ivanov; D L Stienike; D I Ryabchikov; G S Adams; T Adams; Z Bar-Yam; J M Bishop; V A Bodyagin; D S Brown; N M Cason; S U Chung; J P Cummings; K Danyo; S P Denisov; V A Dorofeev; J P Dowd; P Eugenio; X L Fan; R W Hackenburg; M Hayek; D Joffe; I A Kachaev; W Kern; E King; O L Kodolova; V L Korotkikh; M A Kostin; J Kuhn; V V Lipaev; J M LoSecco; J J Manak; J Napolitano; M Nozar; C Olchanski; A I Ostrovidov; T K Pedlar; A V Popov; L I Sarycheva; K K Seth; X Shen; N Shenhav; W D Shephard; N B Sinev; J A Smith; S A Taegar; A Tomaradze; I N Vardanyan; D P Weygand; D B White; H J Willutzki; M Witkowski; A A Yershov; E852 Collaboration

doi:10.1103/PhysRevLett.86.3977

Observation of exotic meson production in the reaction pi- p --> eta'pi- p at 18 GeV/c

Phys Rev Lett. 2001 Apr 30;86(18):3977-80. doi: 10.1103/PhysRevLett.86.3977.

Affiliation

¹ University of Notre Dame, Notre Dame, Indiana 46556, USA.

PMID: 11328074
DOI: 10.1103/PhysRevLett.86.3977

Abstract

An amplitude analysis of an exclusive sample of 5765 events from the reaction pi- p-->eta'pi- p at 18 GeV/c is described. The eta'pi- production is dominated by natural parity exchange and by three partial waves: those with J(PC) = 1(-+), 2(++), and 4(++). A mass-dependent analysis of the partial-wave amplitudes indicates the production of the a2(1320) meson as well as the a4(2040) meson, observed for the first time decaying to eta'pi-. The dominant, exotic (non- qq) 1(-+) partial wave is shown to be resonant with a mass of 1.597+/-0.010(+0.045)(-0.010) GeV/c2 and a width of 0.340+/-0.040+/-0.050 GeV/c2. This exotic state, the pi1(1600), is produced with a t dependence which is different from that of the a2(1320) meson, indicating differences between the production mechanisms for the two states.