$Υ(nS)$ polarizations in $pp$ collisions at $\sqrt{s}=$ 7 and 8 TeV by the LHCb collaboration
A polarization measurement carried out for the $Υ(1S)$, $Υ(2S)$ and $Υ(3S)$ mesons produced in pp collisions at $\sqrt{s}=$ 7 and 8 TeV is presented. Data samples used for the polarization measurement were collected by the LHCb experiment during the 2011 and 2012 data taking runs with integrated luminosities of 1 and 2 fb$^{-1}$, respectively. The measurement has been performed in three polarization frames, using an angular distribution analysis of the $Υ\toμ^{+}μ^{-}$ decays in the kinematic region of the $Υ$ transverse momentum $p_{T}^Υ<30$ GeV/c and rapidity $2.2<y^Υ<4.5$. No large polarization is observed.
hep-ex↗