Nello Paver | Searcharxiv

arXiv2012

Second-class current effects from isospin breaking in tau-->omega pi nu_tau

Second-class weak currents can in the standard model be induced by chiral symmetry breaking. In the specific case of the decay tau-->omega pi nu_tau, dominated by the first-class vector current with the rho quantum numbers, such effects would manifest themselves by small axial vector (or, generally, non-vector) contributions to the decay rate. We present an attempt to estimate such effects, based on a vector and axial-vector dominance model of the relevant matrix elements supplemented by omega-rho mixing. We also give an indication on the amplitude directly mediated by b_1(1235)-->omega pi, in principle also allowed in the standard model by isotopic spin violation.

hep-ph↗

arXiv1997

Penguin corrections and strong phases in a time-dependent analysis of $B^0_{d} \to π^+ π^-$

From a time-dependent analysis of the decay $B^0_{d} \to π^+ π^-$ and using a model-dependent $A_P/A_T$ ratio of the penguin-to-tree amplitudes contributing to the decay, both the weak phase $α$ and the strong phase shift difference $δ$ can be extracted from the data. The value of the weak phase $β$, expected to be measured from the decay $B^0_{d} \to J/ψK_S$, is used to parameterize the value of $A_P/A_T$ and the corresponding penguin correction to the observed asymmetry in $B^0_{d} \to π^+ π^-$.

hep-ph↗