Rare Semileptonic B Meson Decay In Standard Model

Abstract

The semileptonic B!K1(1270; 1400) + ð€€€ decay has been analyzed insthe famework ofsthe Standard Model.sThe nal statesmeson K1(1270) and K1(1400) aresthe mixtures ofsthe K1A and K1B,swhich aresthe 1P1 and 3P1 stateswith mixing angle K1 . In this regard, various observablesssuch as branching ratio BR, forward-backward asymmetry AFB, Longitudinal helicity Fraction fL and ratio of nal state meson K1(1400) to K1(1270), R (K1) = B(B!K1(1400) + ð€€€ ð€€€) = B(B!K1(1270) + ð€€€) have been investigated. To investigate the said observablesswe havesused lightscone QCD sumsrules and thesvalues of mixingsangle are K = ð€€€34o;ð€€€45o;ð€€€57o. It is found that the physical observables under consideration aressensitive tosthe mixing angle K1 forsthe decay B!K1(1400) + ð€€€ ð€€€ and almostsinsensitive forsthe decay B!K1(1270) + ð€€€ ð€€€. It issalso found thatsthe said decays are sensitive to the ratio R (K1). Hence the ratio R (K1) is useful to determine K1 and complement for other observablessto testsSM patameterssand to probe thesstructure ofsNP. v