Double lepton polarization in [formula omitted] decay in the Standard Model with fourth generations scenario

Abstract

This study investigates the influence of the fourth generation quarks on the double lepton polarizations in Λ b → Λ ℓ + ℓ − decay by taking | V t ′ s * V t ′ b | = 0.005 , 0.01 , 0.02 , 0.03 with phase { 60 ° , 90 ° , 120 ° } . We will try to obtain a constrain on the mass of the 4th generation top like quark t ′ , which is consistent with the b → s ℓ + ℓ − rate. With the above mentioned parameters, we will try to show that the double lepton ( μ , τ ) polarizations are quite sensitive to the existence of fourth generation. It can serve as a good tool to search for new physics effects, precisely, to search for the fourth generation quarks ( t ′ , b ′ ) via its indirect manifestations in loop diagrams.