A study of $\upchi _{{\mathrm {b}}}$ meson production at LHCb is performed on proton–proton collision data, corresponding to 3.0 $\text { fb}^{-1}$ of integrated luminosity collected at centre-of-mass energies $\sqrt{s}$ = 7 and 8 $\mathrm {\,TeV}$ . The fraction of $\Upsilon \mathrm {(nS)}$ mesons originating from $\upchi _{{\mathrm {b}}}$ decays is measured as a function of the $\Upsilon $ transverse momentum in the rapidity range $2.0 < y^{\Upsilon } < 4.5$ . The radiative transition of the $\upchi _{{\mathrm {b}}}\mathrm {(3P)}$ meson to $\Upsilon \mathrm {(3S)}$ is observed for the first time. The $\upchi _{{\mathrm {b}} 1}\mathrm {(3P)}$ mass is determined to be $\begin{aligned} m_{\upchi _{{\mathrm {b}} 1}\mathrm {(3P)}} = 10\,511.3 \pm 1.7 \pm 2.5{\mathrm {\,MeV}/c^2}, \end{aligned}$ where the first uncertainty is statistical and the second is systematic.
Fractions $R_{\Upsilon(1S)}^{\chi_{b}(mP)}$ in bins of $p_{\mathrm{T}}^{\Upsilon}$, measured for data collected at $\sqrt{s}= 7$ TeV.
Fractions $R_{\Upsilon(2S)}^{\chi_{b}(mP)}$ in bins of $p_{\mathrm{T}}^{\Upsilon}$, measured for data collected at $\sqrt{s}= 7$ TeV.
Fractions $R_{\Upsilon(3S)}^{\chi_{b}(mP)}$ in bins of $p_{\mathrm{T}}^{\Upsilon}$, measured for data collected at $\sqrt{s}= 7$ TeV.