Abstract:
The semileptonic B!K1(1270; 1400) + 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) +
) = B(B!K1(1270) + ) have been investigated.
To investigate the said observablesswe havesused lightscone QCD sumsrules
and thesvalues of mixingsangle are K = 34o;45o;57o. It is found that the physical
observables under consideration aressensitive tosthe mixing angle K1 forsthe decay
B!K1(1400) +
and almostsinsensitive forsthe decay B!K1(1270) +
. 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.
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