Joao P. Silva — Page 4

arXiv1994

`Natural Masslessness Conservation' for neutrinos in two Higgs-doublet models

We present a model which supplements the Standard Electroweak Model with three right-handed neutrinos and one extra scalar doublet which does not develop a vacuum expectation value. With the aid of a discrete symmetry the neutrinos are kept strictly massless. This model has several interesting features. It has unsuppressed lepton flavour violating processes, in particular $μ\rightarrow e γ$, hinting at the possibility that these may soon be within experimental reach. The $Z$ and $W$ interactions become non-diagonal at one loop level. In particular, a non-trivial leptonic mixing matrix is seen to arise from the clash between the charged gauge boson and the charged scalar interactions.

hep-ph↗

arXiv1993

Determining the Penguin Effect on CP Violation in $B^0 \rightarrow π^+ π^-$

A major goal in B physics is measuring the CP-violating asymmetry in the decay $B^0 \rightarrow π^+ π^-$. In order to determine one of the phase angles in the CKM matrix from this decay it is necessary to determine the influence of the penguin amplitude. Here we show how, using $SU(3)$ symmetry, the penguin effect can be approximately determined from the ratio of the decay rates of $B^0 \rightarrow K^+ π^-$ and $B^0 \rightarrow π^+ π^-$.

hep-ph↗