论文标题
在$ k_ {t} $ - 分解方法内生产LHCB的远期重型风味Dijets
Production of forward heavy-flavour dijets at the LHCb within $k_{T}$-factorization approach
论文作者
论文摘要
我们计算$ c \ bar c $ - 和$ b \ b $ -dijet生产的差分横截面，以$ \ sqrt {s} = 13 $ tev in $ \ sqrt {s scattering，$ k_t $ factorization in $ k_t $ -factorization和Hybrid方法中，以及不同的未融合的零件分配功能（UPDFS）。我们介绍了领先射流的横向动量和伪层的分布，喷气机和二重质量质量之间的速度差异。将我们的结果与最近的LHCB有关重型风味二行的远期产生的数据进行了比较，最近首次单独测量了魅力和底部风味。我们发现，整个$ k_t $ factorization中的预测与数据之间的协议与Gluon Updf的大型$ x $行为的建模密切相关，而Gluon Updfs的大型X $行为通常不太受约束。在混合分解方法之后，可以避免问题。然后，通过Parton分支，Kimber-Martin-Ryskin，Kutak-Sapeta和Jung Seta0 CCFM Gluon Updfs获得了对测量分布的良好描述。我们还计算了$ c \ bar c $和$ b \ b $ b $ cross部分的差分分布。在所有情况下，我们获得的比率接近1，这是由最小喷气横向动量（$ p_ {t}^{\ mathrm {jet}}> 20 $ GEV引入的最小喷气横向动量（$ p_ {t}^{\ p_ {t}^{\ p_ {t}^{\ p_ {t}^{\ mathrm {j JetRm {jet}}> 20 $ gev），这使得重夸克质量的作用几乎可以忽略不计。 LHCB实验比似乎更大。我们讨论了$ C $ - 或$ b $ QUARK GLUON辐射校正与喷气式锥外排放相关的比率效应的可能性很重要。发现的效果似乎很小。更多的精炼计算需要完全模拟$ c $ - 和$ b $ - $ - $ $ $ - 超出了本文范围的范围。
We calculate differential cross sections for $c \bar c$- and $b \bar b$-dijet production in $pp$-scattering at $\sqrt{s} = 13$ TeV in the $k_T$-factorization and hybrid approaches with different unintegrated parton distribution functions (uPDFs). We present distributions in transverse momentum and pseudorapidity of the leading jet, rapidity difference between the jets and the dijet invariant mass. Our results are compared to recent LHCb data on forward production of heavy flavour dijets, measured recently for the first time individually for both, charm and bottom flavours. We found that an agreement between the predictions and the data within the full $k_T$-factorization is strongly related to the modelling of the large-$x$ behaviour of the gluon uPDFs which is usually not well constrained. The problem may be avoided following the hybrid factorization approach. Then a good description of the measured distributions is obtained with the Parton-Branching, the Kimber-Martin-Ryskin, the Kutak-Sapeta and the Jung setA0 CCFM gluon uPDFs. We calculate also differential distributions for the ratio of $c \bar c$ and $b \bar b$ cross sections. In all cases we obtain the ratio close to 1 which is caused by the condition on minimal jet transverse momentum ($p_{T}^{\mathrm{jet}} > 20$ GeV) introduced in the experiment, that makes the role of heavy quark mass almost negligible. The LHCb experimental ratio seems a bit larger. We discuss potentially important for the ratio effect of $c$- or $b$-quark gluon radiative corrections related to emission outside of the jet cone. The found effect seems rather small. More refine calculation requires full simulation of $c$- and $b$-jets which goes beyond of the scope of the present paper.
