论文标题
NRQCD中的底部生产和两极分化，并具有$ k_t $ -Factorization。 II：$υ（2s）$和$χ_b（2p）$ MESON
Bottomonia production and polarization in the NRQCD with $k_T$-factorization. II: $Υ(2S)$ and $χ_b(2P)$ mesons
论文作者
论文摘要
在$ K_T $ -FACTORIZARIZION方法的框架中研究了$υ（2s）$生产和高能化的产生和两极分化。我们的考虑是基于针对硬性党派子过程的界形式和壳生产幅度的非宗教QCD形式主义。直接生产机制，辐射$χ_b（3p）$和$χ_b（2p）$衰减的供供捐款以及$υ（3s）$衰减的贡献。质子中的横向动量依赖性的Gluon密度源自ciafaloni-catani-fiorani-marchesini进化方程，以及Kimber-Martin-ryskin处方。根据Mulitpole辐射理论对待非扰动色八粒八分之一过渡，我们提取了$υ（2s）$和$χ_b（2p）$ erson的相应的非扰动矩阵元素，从合并拟合到$υ（2s）$ the（2s）$ transverseMoment分布到CMS和cms $ qms $ quls $ quls $ quls yhc yhc yhc yhc yhc yhc yhc yhc yhc yhc yhc yhc yhc yhc-s yhc-s yhc-transe septions $ mesons（2p）$ ersons（2p）$ ersons。 $ 13 $ tev和相对生产率$ r^{χ_b（2p）} _ {υ（2s）} $由LHCB协作$ \ sqrt s = 7 $和$ 8 $ TEV所测量的。然后，我们应用提取的值来研究偏振参数$λ_θ$，$ λ_ϕ $和$λ_{θϕ} $，该$ nsublix $λ_θ$，$λ_θ$，$λ_θ$，$λ_θ$，$λ_θ$，$λ_θ$，$λ_θ$，$λ_θ$，$λ_θ$，$λ_θ$，$λ_θ$，$λ_θ$，$λ_θ$，$λ_θ$，$λ_θ$，它确定$υ（2S）$旋转密度矩阵。我们的预测与理论和实验不确定性中当前可用的数据有良好的一致性。
The $Υ(2S)$ production and polarization at high energies is studied in the framework of $k_T$-factorization approach. Our consideration is based on the non-relativistic QCD formalism for bound states formation and off-shell production amplitudes for hard partonic subprocesses. The direct production mechanism, feed-down contributions from radiative $χ_b(3P)$ and $χ_b(2P)$ decays and contributions from $Υ(3S)$ decays are taken into account. The transverse momentum dependent gluon densities in a proton were derived from the Ciafaloni-Catani-Fiorani-Marchesini evolution equation as well as from the Kimber-Martin-Ryskin prescription. Treating the non-perturbative color octet transitions in terms of the mulitpole radiation theory, we extract the corresponding non-perturbative matrix elements for $Υ(2S)$ and $χ_b(2P)$ mesons from a combined fit to $Υ(2S)$ transverse momenta distributions measured by the CMS and ATLAS Collaborations at the LHC energies $\sqrt s = 7$ and $13$ TeV and from the relative production rate $R^{χ_b(2P)}_{Υ(2S)}$ measured by the LHCb Collaboration at $\sqrt s = 7$ and $8$ TeV. Then we apply the extracted values to investigate the polarization parameters $λ_θ$, $λ_ϕ$ and $λ_{θϕ}$, which determine the $Υ(2S)$ spin density matrix. Our predictions have a good agreement with the currently available data within the theoretical and experimental uncertainties.
