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

INSPIRE   JSON  (beta) PDGID:
S049FBJ
VALUE DOCUMENT ID TECN  COMMENT
$\bf{ 0.034 {}^{+0.040}_{-0.029}}$ OUR AVERAGE
$0.02$ ${}^{+0.05}_{-0.03}$ ${}^{+0.02}_{-0.01}$
AAIJ
2013H
LHCB ${{\mathit p}}{{\mathit p}}$ at 7 TeV
$0.13$ $\pm0.09$ $\pm0.02$
AALTONEN
2012I
CDF ${{\mathit p}}{{\overline{\mathit p}}}$ at 1.96 TeV
$-0.04$ ${}^{+0.13}_{-0.16}$ $\pm0.05$
WEI
2009A
BELL ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \Upsilon}{(4S)}}$
• • We do not use the following data for averages, fits, limits, etc. • •
$0.00$ $\pm0.13$ 1
SATO
2016
BELL ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \Upsilon}{(4S)}}$
$0.08$ ${}^{+0.27}_{-0.22}$ $\pm0.07$
AALTONEN
2011L
CDF Repl. by AALTONEN 2012I
1  Statistical uncertainty only.
References