LEPTON (HADRON) FORWARD-BACKWARD ASYMMETRY IN ${{\mathit B}}$ $\rightarrow$ ${{\mathit K}^{(*)}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$ ( ${{\mathit B}}$ $\rightarrow$ ${{\mathit K}}$ $/$ ${{\mathit \pi}}{{\mathit h}^{+}}{{\mathit h}^{-}}$) DECAY

The forward-backward angular asymmetry of the lepton pair in ${{\mathit B}}$ $\rightarrow$ ${{\mathit K}^{(*)}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$ ( ${{\mathit B}}$ $\rightarrow$ ${{\mathit K}}$ $/$ ${{\mathit \pi}}{{\mathit h}^{+}}{{\mathit h}^{-}}$) decay is defined as
A$_{FB}$(s) = ${ N(cos\theta >0) − N(cos\theta <0)\over N(cos\theta >0) + N(cos\theta <0) }$,
where s=q${}^{2}/{{\mathit m}^{2}}_{{{\mathit B}}}$, and $\theta $ is the angle of the ${{\mathit \ell}^{-}}$ (${{\mathit h}^{-}}$) with respect to the flight direction of the ${{\mathit B}}$ meson, measured in the dilepton (dihadron) rest frame. In addition, the fraction of longitudinal polarization F$_{L}$ of the ${{\mathit K}^{*}}$ and F$_{S}$, the relative contribution from scalar and pseudoscalar penguin amplitudes in ${{\mathit B}}$ $\rightarrow$ ${{\mathit K}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$, can be measured from the angular distribution of its decay products.

A$_{FB}$( ${{\mathit B}}$ $\rightarrow$ ${{\mathit X}_{{{s}}}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$) (1.0 $<$ q${}^{2}$ $<$ 6.0 GeV${}^{2}$/c${}^{4}$)

INSPIRE   PDGID:
S049A00
VALUE DOCUMENT ID TECN  COMMENT
• • We do not use the following data for averages, fits, limits, etc. • •
$0.74$ $\pm0.54$ 1
SATO
2016
BELL ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \Upsilon}{(4S)}}$
1  Uses the sum of 10 exclusive ${{\mathit X}_{{{s}}}}$ modes in the range M(${{\mathit X}_{{{s}}}}$) $>$ 1.1 GeV/c${}^{2}$. Uncertainty is statistical only.
References