论文标题
5.02 TEV P+PB碰撞对核PDF的Dijet和D-Meson数据的影响
Impact of dijet and D-meson data from 5.02 TeV p+Pb collisions on nuclear PDFs
论文作者
论文摘要
我们讨论了铅核中Gluon Parton分布函数（PDF）的新约束，可通过5.02 TEV TEV P+Pb测量DIJET（CMS）和$ D^0 $ -Meson（LHCB）核修饰比从5.02 TEV P+PB测量中得出的Hessian PDF重新升级方法。发现影响很大，在中间和以前不受限制的小$ x $区域中施加了严格的限制。 CMS Dijet数据证实了Gluon抗阴影的存在和小$ x $阴影的发作，并减少了较大$ x $区域中的Gluon PDF不确定性。 lhcb $ d^0 $数据的Gluon约束，达到$ x \ sim 10^{ - 5} $，并以NLO扰动QCD方法派生，可显着减少Small-$ x $不确定性，并具有强有力的直接证据的Gluon Shadewing。此外，我们在纯粹的基于DGLAP的方法中发现了对数据的良好描述，甚至$ d^0 $ -Meson横向动量，而无需施加任何非线性效果。重要的是，从Dijet获得的约束和$ d^0 $数据是完全一致的，从而支持核PDF在硬散发过程中的普遍性。
We discuss the new constraints on gluon parton distribution function (PDF) in lead nucleus, derivable with the Hessian PDF reweighting method from the 5.02 TeV p+Pb measurements of dijet (CMS) and $D^0$-meson (LHCb) nuclear modification ratios. The impact is found to be significant, placing stringent constraints in the mid- and previously unconstrained small-$x$ regions. The CMS dijet data confirm the existence of gluon anti-shadowing and the onset of small-$x$ shadowing, as well as reduce the gluon PDF uncertainties in the larger-$x$ region. The gluon constraints from the LHCb $D^0$ data, reaching down to $x \sim 10^{-5}$ and derived in a NLO perturbative QCD approach, provide a remarkable reduction of the small-$x$ uncertainties with a strong direct evidence of gluon shadowing. Furthermore, we find a good description of the data even down to zero $D^0$-meson transverse momentum within a purely DGLAP-based approach without a need for imposing any non-linear effects. Importantly, the constraints obtained from the dijet and $D^0$ data are mutually fully consistent, supporting the universality of nuclear PDFs in hard-scattering processes.
