Universal Deviations from the Wigner Threshold Law,

P. A. MACRI; R. O. BARRACHINA

Bonn, Alemania

Conferencia; 19th International IUPAP Conference on Few Body Problems in Physics; 2009

The International Union of Pure and Applied Physics

Few body systems where two particles have similar momenta are of particular interest in Atomic,Molecular, Nuclear and Particle Physics [1-4]. Since 60 years ago, the near threshold behavior of the corresponding cross sections is described by the Wigner threshold law (WTL)[5]. Although collisions in these energy regimes show many conspicuous effects -like resonances, cusps, dips and step structures- which are known to restrain the scope of the WTL, up to now there is no theoretical estimation of its range of applicability or even less how these e®ects modify its behavior. The importance of revealing these matters of low energy scattering are increasingly more pressing with the advance of modern atomic and molecular physics ¯elds such as Bose-Einstein condensation, atom interferometers and atomic clocks. Collisions at thresholds are experimentally tested now at unprecedentedly low energies. For example, ...