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$_{FB}({{\mathit B}}$ $\rightarrow$ ${{\mathit K}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$) (0.0 $<$ q${}^{2}<$ 4.3 GeV${}^{2}$/c${}^{4}$)

INSPIRE   JSON  (beta) PDGID:
S049FBK
VALUE DOCUMENT ID TECN  COMMENT
$0.31$ $\pm0.16$ $\pm0.04$
AALTONEN
2012I
CDF ${{\mathit p}}{{\overline{\mathit p}}}$ at 1.96 TeV
• • We do not use the following data for averages, fits, limits, etc. • •
$0.36$ ${}^{+0.24}_{-0.26}$ $\pm0.06$
AALTONEN
2011L
CDF Repl. by AALTONEN 2012I
References