Measurement of $J/\ddot{I}ˆ$ polarization in $pp$ collisions at $\sqrt{s}=7$ TeV

Abstract

An angular analysis of the decay $J/\ddot{I}ˆ\to \hat{I}{¼}^{+}\hat{I}{¼}^{-}$ is performed to measure the polarization of prompt $J/\ddot{I}ˆ$ mesons produced in $pp$ collisions at $\sqrt{s}=7\mathrm{TeV}$. The dataset corresponds to an integrated luminosity of 0.37 fb${}^{-1}$ collected with the LHCb detector. The measurement is presented as a function of transverse momentum, $p_{\mathrm{T}}$, and rapidity, $y$, of the $J/\ddot{I}ˆ$ meson, in the kinematic region $2<p_{\mathrm{T}}<15\mathrm{GeV}/c$ and $2.0<y<4.5$.

21 pages, 7 figures