Single- W production and Fermion-Loop scheme: numerical results

Single-W Production and Fermion-Loop Scheme: Numerical Results

The single-W production mechanism is synonymous to the e+e− annihilation into eνe and a W boson with the outgoing electron lost in a small cone around the beam direction. It requires a Renormalization Scheme that preserves gauge invariance and fermion masses cannot be neglected in the calculation. A recently proposed generalization of the so-called Fermion-Loop scheme is applied to the evaluati...

Fermion Loops, conserved currents and single-W

The problem of preserving gauge invariance in the calculations involving unstable particles is well known since several years [1–4] . It is connected with the fact that the use of a width (e.g. iΓM) in the denominator of an s-channel unstable boson propagator is necessary to prevent divergences at p = M, but it is in fact an effective way of including only a part of higher order corrections, an...

Two-loop Corrections to Fermion Pair Production Vertices†

Recent results on the entirely analytic calculation of second order corrections to massive quark pair production vertices induced by light quark flavours are reviewed. Based on the method presented in this talk the second order effects of the insertion of any massless one-loop vacuum polarization into the gluon line of the first order diagrams can be determined. The behaviour of the corrections...

Single W and Anomalous Single Top Production at HERA

The search for events containing isolated leptons (electrons or muons) and missing transverse momentum produced in ep collisions is performed individually and in a common phase space with the H1 and ZEUS detectors at HERA in the period 1994–2007. The presented H1+ZEUS data sample corresponds to an integrated luminosity of 0.97 fb, and comprises the complete high energy data from the HERA progra...

Two-Loop Soft Anomalous Dimensions for Single Top Quark Associated Production with a W- or H-