[G12] Exotic from today's archive

[Valery Kubarovsky]

Hi Craig,
Take a look:

[4]  arXiv:0910.5842 [pdf, other]
Observation of a J^PC = 1-+ exotic resonance in diffractive
dissociation of 190 GeV/c pi- into pi- pi- pi+
The COMPASS Collaboration: A. Alekseev, et al
Comments: 7 page, 3 figures
Subjects: High Energy Physics - Experiment (hep-ex)
The COMPASS experiment at the CERN SPS has studied the diffractive
dissociation of negative pions into the pi- pi- pi+ final state using
a 190 GeV/c pion beam hitting a lead target. A partial wave analysis
has been performed on a sample of 420000 events taken at values of the
squared 4-momentum transfer t' between 0.1 and 1 GeV^2/c^2. The
well-known resonances a1(1260), a2(1320), and pi2(1670) are clearly
observed. In addition, the data show a significant natural parity
exchange production of a resonance with spin-exotic quantum numbers
J^PC = 1-+ at 1.66 GeV/c^2 decaying to rho pi. The resonant nature of
this wave is evident from the mass-dependent phase differences to the
J^PC = 2-+ and 1++ waves. From a mass-dependent fit a resonance mass
of 1660 +- 10+0-64 MeV/c^2 and a width of 269+-21+42-64 MeV/c^2 is
deduced.

Valery