Neutral current couplings of higher generations

Charged and Neutral Current Couplings of Quarks

Flavour Changing Neutral Current Effects from Flavour Dependent Supergravity Couplings

We investigate the impact on low energy flavour mixing phenomena of the renormalisation group running of parameters in supersymmetric theories. We have explicitly chosen flavour dependent supergravity couplings. The renormalisation group equations are displayed in general matrix form. We work in a scale dependent basis such that the hierarchy in the quark masses can be more easily utilised. Sim...

Polarized Bhabha scattering and a precision measurement of the electron neutral current couplings.

The cross section for Bhabha scattering (e + e − → e + e −) with polarized electrons at the center of mass energy of the Z 0 resonance has been measured with the SLD experiment at the SLAC Linear Collider (SLC) during the 1992 and 1993 runs. The first measurement of the left-right asymmetry in Bhabha scattering (A e + e − LR (|cosθ|)) is presented. From A e + e − LR (|cosθ|) the effective weak ...

Neutral Current Couplings of Leptons to Polarized Z 0 ' s in the SLD Experiment

We study neutral current couplings of leptons to polarized Z 0 's in the SLD experiment in terms of the leptonic asymmetry parameters A e , A and A. W e discuss in detail e , L;R + e + ! Z 0 ! , + and , + , with leftL-or rightR-handed polarized electron beams. SLD's most precise measurement o f A e is shown to result from the left-right cross section asymmetry, A LR , where the dependence on in...

Search for production of single top quarks via tcg and tug flavor-changing-neutral-current couplings.

We search for the production of single top quarks via flavor-changing-neutral-current couplings of a gluon to the top quark and a charm (c) or up (u) quark. We analyze 230 pb{-1} of lepton+jets data from pp[over] collisions at a center of mass energy of 1.96 TeV collected by the D0 detector at the Fermilab Tevatron Collider. We observe no significant deviation from standard model predictions, a...