论文标题
内在魅力产生的能量依赖性：观察的最佳能量是什么？
Energy Dependence of Intrinsic Charm Production: What is the Best Energy for Observation?
论文作者
论文摘要
背景：1980年代初期预测了一种非扰动的魅力生产贡献，称为内在魅力。最近的结果为其存在提供了新的证据，但需要进一步确认。目的：$ j/ψ$和$ \ bar d $ Meson的生产是通过扰动QCD和内在魅力的组合来计算的，以确定研究内在魅力生产的最佳能量范围。方法：$ J/ψ$和$ \ bar d $ Meson生产以扰动QCD计算到横截面中的近代订单。在两者的生产中考虑了冷核物质的影响，包括对Parton密度的核修饰和多个散射的$ P_T $扩展； $ J/ψ$还包括核子的吸收。假设从$ | uud c \ bar c \ rangle $ fock state产生产量，则可以计算出固有魅力的贡献。结果：$ J/ψ$和$ \ bar d $ Meson Rapidity和$ p_t $发行量是根据迅速和横向动量$ p_t $在$ p+p $碰撞中具有内在符号的广泛质量中心能量的函数计算的。还以适当的能量以$ p+{\ rm pb} $相互作用计算核修饰因子$ r_ {pa} $。还将以前的固定目标数据作为feynman $ x $，$ x_f $的函数与该方法中的计算进行了比较。当包括内在魅力时，可以发现与数据的良好一致。结论：对于未来的低能量固定目标实验，例如提出的NA60+，内在的魅力信号可能是中等范围的最大信号。
Background: A nonperturbative charm production contribution, known as intrinsic charm, was predicted in the early 1980s. Recent results have provided new evidence for its existence but further confirmation is needed. Purpose: $J/ψ$ and $\bar D$ meson production are calculated with a combination of perturbative QCD and intrinsic charm to determine the best energy range to study intrinsic charm production. Methods: $J/ψ$ and $\bar D$ meson production are calculated in perturbative QCD to next-to-leading order in the cross section. Cold nuclear matter effects, including nuclear modification of the parton densities and $p_T$ broadening by multiple scattering are taken into account in the production of both; absorption by nucleons is also included for the $J/ψ$. Contributions from intrinsic charm are calculated assuming production from a $|uud c \bar c \rangle$ Fock state. Results: The $J/ψ$ and $\bar D$ meson rapidity and $p_T$ distributions are calculated as a function of rapidity and transverse momentum $p_T$ over a wide range of center-of-mass energies with and without intrinsic charm in $p+p$ collisions. The nuclear modification factor, $R_{pA}$, is also calculated for $p+{\rm Pb}$ interactions at appropriate energies. Previous fixed-target data as a function of Feynman $x$, $x_F$, are also compared to calculations within the approach. Good agreement with the data is found when intrinsic charm is included. Conclusions: The intrinsic charm signal may be largest at midrapidity for future low energy fixed target experiments such as the proposed NA60+.
