Tuesday, February 19, 2013

1302.4065 (Michael Döring et al.)

Finite volume effects and quark mass dependence of the N(1535) and

Michael Döring, Maxim Mai, Ulf-G. Meißner
For resonances decaying in a finite volume, the simple identification of state and eigenvalue is lost. The extraction of the scattering amplitude is a major challenge as we demonstrate by extrapolating the physical S_{11} amplitude of pion-nucleon scattering to the finite volume and unphysical quark masses, using a unitarized chiral framework including all next-to-leading order contact terms. We show that the pole movement of the resonances N(1535)1/2^- and N(1650)1/2^- with varying quark masses is non-trivial. In addition, there are several strongly coupled S-wave thresholds that induce a similar avoided level crossing as narrow resonances. The level spectrum is predicted for two typical lattice setups, and ways to extract the amplitude from upcoming lattice data are discussed.
View original: http://arxiv.org/abs/1302.4065

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