C. Deom

The hard neutron-proton bremsstrahlung at 76 MeV

The neutron-proton bremmstrahlung cross-section was measured at a neutron energy of 76 MeV. Outgoing protons and neutrons were detected at extreme forward laboratory angles. Measurements were compared with a soft-photon-approximation calculation. Non-coplanar events were also studied.

Radiative corrections to sin2 θ W exp in theS U(5) model

We compute perturbatively in theSU(5) grand unification theory the radiative corrections to sin2θWO through a phenomenological weak mixing angle, sin2θWexp(q2), defined in thevμe elastic scattering. We essentially recover the results obtained by using the renormalization group analysis.

DETERMINATION OF SIN**2-theta-w BY THE MINIMIZATION OF RADIATIVE CORRECTIONS TO THE WEAK ISOSPIN BREAKING

Abstract In the SU(2)L ⊗ U(1) theory, the weak isospin breaking is responsible for the difference between the W-coupling, ĝ2(μ) (defined in the MS scheme) and the Z-coupling, g Z (μ) ≡ [ g 2 1 (μ) + g 2 2 (μ)] 1 2 . It is shown that the requirement of weak isospin symmetry in the radiative corrections of the gauge couplings, i.e. d g 2 (μ) − d g Z (μ) = 0 , with μ ≌ m W implies implies sin 2 θ (m W ) = 0.22, m W ≌ 82 GeV and m Z ≌ 93 GeV .