Multiparton interactions and higher-twist effects

本计画致力于研究在硬尺度下，具有次主导力量的散射过程的贡献。超越领先功率精度的重要性已得到广泛认可。一个原因是，这样的贡献限制了基于领先功率（领先扭曲）因式分解定理的QCD描述的最终精度。他们需要理解的理论，以匹配非常高的数据精度预期在下一代的实验设施。这特别涉及EIC和JLAB 12物理计划核心的排他性和半包容性反应，其中大部分数据都集中在中等动量转移上。另一个原因是，在相空间的某些区域中，高扭曲的贡献实际上变得不受抑制。强子-强子碰撞中的多部分子散射过程就是一个很好的例子。由于它们的重要性随着碰撞能量的增加而增加，它们在大型强子对撞机上引起了相当大的兴趣（在未来可能的强子对撞机上更是如此）。高捻效应的主题是非常多样化的，涵盖了各种各样的工艺和方法。在第二个资助期内，我们专注于研究双重部分子分布和对深度虚康普顿散射的更高扭曲修正。该项目的研究补充了项目P1、P2和P4中高阶微扰校正的计算，目标是实现基准观测值的最高精度。

This project is devoted to the study of contributions to scattering processes that are formally of subleading power in the hard scale. The importance of going beyond the leading power accuracy is widely recognized. One reason is that such contributions constrain the ultimate accuracy of QCD description based on leading-power (leading-twist) factorization theorems. They need to be understood for the theory to match the very high data accuracy expected at the experimental facilities of the next generation. This concerns especially exclusive and semi-inclusive reactions at the heart of the physics programs of the EIC and JLAB12, where the bulk of data is and will be concentrated at moderate momentum transfers. Another reason is that higher-twist contributions actually become unsuppressed in certain regions of phase space. A prime example is provided by multiparton scattering processes in hadron-hadron collisions. As their importance grows with the collision energy, they are of considerable interest at the LHC (and even more so at possible future hadron colliders). The subject of higher twist effects is very diverse and covers a large variety of processes and methods. In the second funding period, we concentrate on the study of double parton distributions and on higher-twist corrections to the deeply-virtual Compton scattering. The studies in this project complement the calculation of higher-order perturbative corrections in projects P1, P2 and P4 with the goal to achieve highest possible precision for benchmark observables.