Eur. Phys. J. C (2008) 56: 267-277
https://doi.org/10.1140/epjc/s10052-008-0643-1

Regular Article - Theoretical Physics

Lepton polarization asymmetry and forward–backward asymmetry in exclusive B→K₁τ⁺τ^- decay in universal extra dimension scenario

¹ Department of Physics, Quaid-i-Azam University, Islamabad, Pakistan
² National Centre for Physics, Islamabad, Pakistan
³ Institute of High Energy Physic, P.O. Box 918(4), Beijing, 100049, P.R. China
⁴ Department of Physics, COMSATS Institute of Information Technology, Chak Shahzad Campus, Islamabad, Pakistan

^* e-mail: jamil@ncp.edu.pk

Received: 9 March 2008
Revised: 7 May 2008
Published online: 27 June 2008

Abstract

Decay rate, forward–backward asymmetry and polarization asymmetries of the final state leptons in B→K₁τ⁺τ^-, where K₁ is the axial vector meson, are calculated in the standard model and in the universal extra dimension (UED) model. The sensitivity of the observables to the compactification radius R, the only unknown parameter in the UED model, is studied. Finally, the helicity fractions of the final state K₁ are calculated and their dependence on the compactification radius is discussed. This analysis of the helicity fraction is briefly extended to B→K^*ℓ⁺ℓ^- (ℓ=e,μ) and compared with the other approaches existing in the literature.