标题： QCD和内在重夸克对领先底夸克和魅夸克强子产生预测 显示英文标题

标题： QCD and Intrinsic Heavy Quark Predictions for Leading Charm and Beauty Hadroproduction

摘要： 费米实验室和欧洲核子研究中心的最新实验观察到，包含入射体价夸克的领先$D$介子的强子产生截面与不包含入射体价夸克的非领先粲介子之间存在显著不对称性。 观测到的$\pi^{\pm} N \to D^\pm X$截面与入射体电荷的相关性违反了通常假设的重夸克喷注碎片化可分离的假设。 我们假设一个两组分模型，结合领先扭度融合子过程和来自内在重夸克福克态的粲产生，研究领先和非领先粲产生之间的不对称性作为$x_f$和$p_T^2$的函数。 我们预测在低$p_T^2$和高$x_f$下，由于粲夸克与入射体共动的旁观者夸克的结合，会产生显著的不对称性。 内在的$c \overline c$产生截面为 0.5$\mu$b 足够解释不对称性的大小和运动学依赖性。 相反，PYTHIA 中包含的底夸克喷注化机制即使在低$x_F.$下也预测了显著的领先底夸克不对称性。 两组分模型被扩展以预测质子-质子和介子-质子相互作用中$B$介子产生的不对称性。 显示英文摘要

摘要： Recent experiments at Fermilab and CERN have observed a strong asymmetry between the hadroproduction cross sections of leading $D$ mesons, containing projectile valence quarks, and nonleading charmed mesons, without projectile valence quarks. The observed correlations of the $\pi^{\pm} N \to D^\pm X$ cross section with the projectile charge violates the usual assumption that heavy quark jet fragmentation factorizes. We examine the asymmetry between leading and nonleading charm production as a function of $x_f$ and $p_T^2$ assuming a two-component model combining leading-twist fusion subprocesses and charm production from intrinsic heavy quark Fock states. We predict a sizable asymmetry at low $p_T^2$ and high $x_f$ from coalescence of the charm quarks with the comoving spectator quarks of the projectile. An intrinsic $c \overline c$ production cross section of 0.5 $\mu$b is sufficient to explain both the magnitude and kinematic dependence of the asymmetry. In contrast, the charm jet hadronization mechanisms contained in PYTHIA predict a sizeable leading charm asymmetry even at low $x_F.$ The two-component model is extended to predict the asymmetry in $B$ meson production in proton-proton and pion-proton interactions.