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

Abstract

An angular analysis of the decay $J/ψ\rightarrow μ^{+} μ^{-}$ is performed to measure the polarization of prompt $J/ψ$ 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 $J/ψ$ meson, in the kinematic region $2 < p_\mathrm{T} < 15\; \mathrm{GeV}/c$ and $2.0<y<4.5$.

21 pages, 7 figures