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   PDGID:
S049FBE
VALUE DOCUMENT ID TECN  COMMENT
$\bf{ -0.078 \pm0.022}$ OUR AVERAGE  Error includes scale factor of 1.1.
$-0.073$ $\pm0.021$ $\pm0.002$ 1
AAIJ
2020Y
 LHCB ${{\mathit p}}{{\mathit p}}$ at 7, 8, 13 TeV
$-0.12$ $\pm0.08$
KHACHATRYAN
2016D
 CMS ${{\mathit p}}{{\mathit p}}$ at 7, 8 TeV
$0.21$ ${}^{+0.10}_{-0.15}$ ${}^{+0.07}_{-0.09}$ 2
LEES
2016C
 BABR ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \Upsilon}{(4S)}}$
$-0.17$ $\pm0.06$ $\pm0.01$
AAIJ
2013Y
 LHCB ${{\mathit p}}{{\mathit p}}$ at 7 TeV, ${{\mathit K}^{*0}}{{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$
$0.29$ ${}^{+0.20}_{-0.23}$ $\pm0.07$
AALTONEN
2012I
 CDF ${{\mathit p}}{{\overline{\mathit p}}}$ at 1.96 TeV
$0.26$ ${}^{+0.27}_{-0.30}$ $\pm0.07$
WEI
2009A
 BELL ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \Upsilon}{(4S)}}$
• • We do not use the following data for averages, fits, limits, etc. • •
$-0.075$ ${}^{+0.032}_{-0.034}$ $\pm0.007$ 1
AAIJ
2016B
 LHCB Repl. by AAIJ 2020Y
$0.55$ $\pm0.43$ 3
SATO
2016
BELL ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \Upsilon}{(4S)}}$
$-0.07$ $\pm0.12$ $\pm0.01$
CHATRCHYAN
2013BL
 CMS Repl. by KHACHATRYAN 2016D
$-0.06$ ${}^{+0.13}_{-0.14}$ $\pm0.07$
AAIJ
2012U
 LHCB Repl. by AAIJ 2013Y
$0.43$ ${}^{+0.36}_{-0.37}$ $\pm0.06$
AALTONEN
2011L
 CDF Repl. by AALTONEN 2012I
1  Measured in 1.1 $<$ q${}^{2}<$ 6.0 GeV${}^{2}$/c${}^{4}$.
2  Measured by combining ${{\mathit B}^{0}}$ and ${{\mathit B}^{+}}$ with ${{\mathit e}}$ and ${{\mathit \mu}}$ as leptons. Results are also provided separately for ${{\mathit B}^{0}}$ and ${{\mathit B}^{+}}$.
3  Uses ${{\mathit K}^{*}}$ $\rightarrow$ ${{\mathit K}^{-}}{{\mathit \pi}^{+}}$, ${{\mathit K}^{-}}{{\mathit \pi}^{0}}$, ${{\mathit K}_S^0}$ ${{\mathit \pi}^{-}}$ in the range M(${{\mathit K}}{{\mathit \pi}}$) $<$ 1.1 GeV/c${}^{2}$. Uncertainty is statistical only.
References