FORWARD-BACKWARD ASYMMETRIES

The forward-backward assymmetry is defined as A$_{FB}({{\mathit \Lambda}_{{b}}^{0}}$) = [ N(F) $−$ N(B)] $/$ [N(F) + N(B) ], where the forward (F) direction corresponds to a particle (${{\mathit \Lambda}_{{b}}^{0}}$ or ${{\mathit \Lambda}_{{b}}^{-}}$) sharing valence quark flavors with a beam particle with the same sign of rapidity.

A${}^{h}_{FB}$( ${{\mathit p}}{{\mathit \pi}}$ ) in ${{\mathit \Lambda}_{{b}}}$ $\rightarrow$ ${{\mathit \Lambda}}$( ${{\mathit p}}{{\mathit \pi}}$) ${{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$

INSPIRE   PDGID:
S040A03
VALUE DOCUMENT ID TECN  COMMENT
$-0.30$ $\pm0.05$ $\pm0.02$ 1
AAIJ
2018AP
 LHCB ${{\mathit p}}{{\mathit p}}$ at 7, 8, 13 TeV
• • We do not use the following data for averages, fits, limits, etc. • •
$-0.29$ $\pm0.07$ $\pm0.03$ 2
AAIJ
2015AE
 LHCB Repl. by AAIJ 2018AP.
1  The measurement covers 15.0 $<$ q${}^{2}$ $<$ 20.0 GeV${}^{2}$/c${}^{4}$.
2  AAIJ 2015AE measurement covers 15.0 $<$ q${}^{2}$ $<$ 20.0 GeV${}^{2}$/c${}^{4}$.
References:
AAIJ 2018AP
JHEP 1809 146 Angular moments of the decay $\Lambda_b^0 \rightarrow \Lambda \mu^{+} \mu^{-}$ at low hadronic recoil
AAIJ 2015AE
JHEP 1506 115 Differential Branching Fraction and Angular Analysis of ${{\mathit \Lambda}_{{b}}^{0}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$ Decays
Also
JHEP 1809 145 (errat.) Differential branching fraction and angular analysis of $\Lambda^{0}_{b} \rightarrow \Lambda \mu^+\mu^-$ decays