Properties of the Lambda(1670)(1-)/2 resonance

Phys Rev Lett. 2002 Jan 7;88(1):012002. doi: 10.1103/PhysRevLett.88.012002. Epub 2001 Dec 14.

Abstract

Recently the Crystal Ball Collaboration measured precise new data for the near-threshold reaction K(-)p-->etaLambda, which is dominated by formation of the Lambda(1670)1 / 2(-). In this Letter, we present results of a unitary, multichannel analysis that incorporates the new Crystal Ball data. For our preferred fit, we obtain mass M = 1673+/-2 MeV, width Gamma = 23+/-6 MeV, and elasticity x = 0.37+/-0.07. This elasticity is significantly larger than previously recognized. Resonance parameters of our preferred fit are in striking agreement with the quark-model predictions of Koniuk and Isgur.