Flavour-changing neutral
currents in models
with extra Z’ boson
S SAHOO1 and L MAHARANA2
1Department of Physics, National Institute of Technology, Durgapur 713
209, India
2Department of Physics, Utkal University, Bhubaneswar 751 004, India
E-mail: sukadevsahoo@yahoo.com;
lmaharan@iopb.res.in
Abstract. New neutral gauge bosons ${Z}'$ are the features of many
models addressing the
physics beyond the
standard model. Together with the existence of new
neutral gauge bosons, models based on extended gauge groups
(rank $>$ 4)
often predict new
charged fermions also. A mixing of the known fermions with
new states, with exotic weak-isospin assignments (left-handed singlets and
right-handed doublets) will induce tree-level flavour-changing neutral
interactions mediated by $Z$ exchange, while if the mixing is only with new
states with ordinary weak-isospin assignments, the
flavour-changing neutral
currents are mainly due to the exchange of the new neutral
gauge boson
${Z}'$. We review
flavour-changing neutral currents in models with extra
${Z}'$ boson. Then we discuss
some flavour-changing processes forbidden in
the standard model and new contributions to standard model
processes.
Keywords. Standard model; flavour-changing neutral currents; $Z’$ gauge
boson; $E_6$
model.