Friday, December 13, 2002, 16:00
WHGA Auditorium
Prof. F. Glück, Mainz/Budapest
Abstract:
Low energy hadronic beta decays are theoretically
simpler and more reliable
than high energy decays. They allow to
test the V-A structure
of the Standard Model to high accuracy. In addition,
the precise determination of V_{ud}
provides (together with V_{us}) the most precise
test of the CKM unitarity. Present neutron
and 0^+ -> 0^+ Fermi decays show 2-3 sigma deviations
from unitarity.
Deviations from the V-A model are parametrized by the
right-handed vector and axialvector, and the left-handed
and right-handed scalar and tensor weak coupling constants.
A phenomenological review of these couplings is presented.
Radiative corrections are important in the analyses of precision
beta decay measurements. For example: the internal bremsstrahlung
photons change the kinematics of the beta decay process.
We present a review (with simple explanations of the bremsstrahlung,
virtual, model independent and model dependent corrections, etc.)
which is hopefully useful also for experimentalists
interested in beta decays.