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$_{FB}$( ${{\mathit B}}$ $\rightarrow$ ${{\mathit K}^{*}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$) (16.0 $<$ q${}^{2}<$ 19.0 GeV${}^{2}$/c${}^{4}$)

INSPIRE   PDGID:
S049FBD
VALUE DOCUMENT ID TECN  COMMENT
$\bf{ 0.362 \pm0.019}$ OUR AVERAGE
$0.353$ $\pm0.020$ $\pm0.010$ 1
AAIJ
2020Y
LHCB ${{\mathit p}}{{\mathit p}}$ at 7, 8, 13 TeV
$0.35$ $\pm0.07$ $\pm0.01$
KHACHATRYAN
2016D
CMS ${{\mathit p}}{{\mathit p}}$ at 8 TeV
$0.30$ $\pm0.08$ ${}^{+0.01}_{-0.02}$
AAIJ
2013Y
LHCB ${{\mathit p}}{{\mathit p}}$ at 7 TeV, ${{\mathit K}^{*0}}{{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$
$0.41$ $\pm0.05$ $\pm0.03$
CHATRCHYAN
2013BL
CMS ${{\mathit p}}{{\mathit p}}$ at 7 TeV
$0.65$ ${}^{+0.17}_{-0.18}$ $\pm0.16$
AALTONEN
2012I
CDF ${{\mathit p}}{{\overline{\mathit p}}}$ at 1.96 TeV
$0.66$ ${}^{+0.11}_{-0.16}$ $\pm0.04$
WEI
2009A
BELL ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \Upsilon}{(4S)}}$
• • We do not use the following data for averages, fits, limits, etc. • •
$0.355$ $\pm0.027$ $\pm0.009$ 1
AAIJ
2016B
LHCB Repl. by AAIJ 2020Y
$0.16$ ${}^{+0.11}_{-0.13}$ $\pm0.06$
AAIJ
2012U
LHCB Repl. by AAIJ 2013Y
$0.70$ ${}^{+0.16}_{-0.25}$ $\pm0.10$
AALTONEN
2011L
CDF Repl. by AALTONEN 2012I
1  Measured in 15.0 $<$ q${}^{2}<$ 19.0 GeV${}^{2}$/c${}^{4}$.
References