Eur. Phys. J. C 29, 11-17 (2003)
DOI: 10.1140/epjc/s2003-01221

Singular cross sections in muon colliders

C. Dams and R. Kleiss

University of Nijmegen, Institute for Theoretical Physics, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands

chrisd@sci.kun.nl
kleiss@sci.kun.nl

(Received: 4 March 2003 / Revised version: 8 April 2003 / Published online: 23 May 2003 )

Abstract
We address the problem that the cross section for the collisions of unstable particles diverges, if calculated by standard methods. This problem is considered for beams much smaller than the decay length of the unstable particle, much larger than the decay length and finally also for pancake- shaped beams. We find that in all cases this problem can be solved by taking into account the production/propagation of the unstable particle and/or the width of the incoming wave packets in momentum space.

© Società Italiana di Fisica, Springer-Verlag 2003