Click here to view fulltext PDF

Permanent link:
https://www.ias.ac.in/article/fulltext/pram/034/03/0183-0192

Scattering theory; S matrix; resonance poles; Δ (1232) resonance; Breit-Wigner formula; shadow poles

We show how the position and residue of theS matrix pole can remain stable under changes in the form of the parametrization of theS matrix elements. We also derive a relation among the shifts in the Breit-Wigner resonance parameters under the same changes and verify the relation numerically for the case of Δ(1232). Despite its stability, the pole does not provide a unique definition of the resonance because of the existence of shadow poles.

G Rajasekaran^{1 2 3} S S Vasan^{2 3}

1. Department of Theoretical Physics, University of Madras, Guindy Campus, Madras - 600025, India
2. Tata Institute of Fundamental Research, Homi Bhabha Road, Bombay - 400 005, India
3. the Institute of Mathematical Sciences, Madras - 600 013, India

Published

March 1990

Manuscript received

5 June 1989

Manuscript revised

4 December 1989