Double Lepton Polarization in $\Lambda_b -->\Lambda l^+ l^-$ Decay in the Standard Model with Fourth Generations Scenario

TL;DR

This paper explores how hypothetical fourth-generation quarks could influence double lepton polarization in a specific baryon decay, aiming to identify signs of new physics beyond the Standard Model.

Contribution

It introduces a method to constrain the mass of the fourth-generation top-like quark using decay polarization data, highlighting its sensitivity to new physics effects.

Findings

Double lepton polarizations are highly sensitive to fourth-generation quark parameters.

The study provides potential constraints on the mass of the fourth-generation top-like quark.

Polarization measurements could serve as indirect evidence for new quark generations.

Abstract

This study investigates the influence of the fourth generation quarks on the double lepton polarizations in \Lambda_b --> \Lambda \ell^+ \ell^- decay by taking |V^\ast_{t's}V_{t'b}|= 0.005,0.01,0.02,0.03 with phase \{60^\circ,90^\circ,120^\circ\}. 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\ell^+\ell^- rate . With the above mentioned parameters, we will try to show that the double lepton(muon, tau) 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.