Speaker
Description
Prompt production of $\Upsilon$(1S,2S,3S) mesons in proton-proton collisions at the LHC within NRQCD $k_t$-factorization approach [1] will be discussed. Different unintegrated gluon distribution functions are used.We include both direct color-singlet production $gg \to \Upsilon(1S) g$ as well as feed-down from $\chi_{b} \to \Upsilon(1S) \gamma$ and $ \ Upsilon(2S) \to \Upsilon (1S) X$. We calculate also the ratio of the cross sections for $\chi_{b}(2)\chi_{b} (1)$ and the corresponding results will be presented. We will compare our results for $\Upsilon$ production with the CMS experimental data [2] for different intervals of rapidity. Differential distributions in rapidity and transverse momentum of $\Upsilon$ states are calculated and compared to experimental data of the CMS [2] and LHCb [3] collaborations. We will present also results for different values of collision energy.
[1] A. Cisek and A. Szczurek, a paper in preparation.
[2] CMS Collaboration, Phys. Lett. $\bf{B743}$, (2015) 383.
[3] LHCb Collaboration, JHEP 11 (2015) 103.
