论文标题
在指南针未极化的半熟悉的dis中的方位角不对称
Azimuthal Asymmetries in Unpolarised Semi-Inclusive DIS at COMPASS
论文作者
论文摘要
在半包含的深度非弹性散射（SIDIS）中，Partons的非零横向动量诱导了横截面的方位角依赖性。对于非成成核，可以与扭曲或更高扭曲横向动量依赖的pDF和碎片函数的不同组合有关的三个方位调节：所谓的CAHN效应反映在$ \ cosCocccompantim {h}中，$ \ cos2和$ \ sinϕ_ \ mathrm {h} $ twist-三个效果，称为束旋转不对称。在2016年和2017年，使用纵向极化的160〜GEV/$ C $ MUON束散射在液体氢目标上的纵向极化的160〜GEV/$ C $ MUON束散射，在CERN的指南针实验收集了大量的SIDIS事件。从数据的一部分提取了上述方位角调制的幅度。已经开发了一种新的程序，以减去衍射产生的媒介膜的衰减的背景。本演讲中提出的结果定性地与Isscalar目标获得的早期指南针结果一致。
In semi-inclusive deep inelastic scattering (SIDIS) the non-zero transverse momentum of partons induces azimuthal dependence of the cross-section. For unpolarised nucleon, three azimuthal modulations that can be related to different combinations of twist-two or higher twist transverse momentum dependent PDFs and fragmentation functions arise: the so-called Cahn effect reflected in $\cosϕ_\mathrm{h}$ modulation, the $\cos2ϕ_\mathrm{h}$ term related to the Boer--Mulders PDF and $\sinϕ_\mathrm{h}$ twist-three effect known as beam-spin asymmetry. In 2016 and 2017, the COMPASS experiment at CERN collected a large sample of SIDIS events using a longitudinally polarised 160~GeV/$c$ muon beam scattering on a liquid hydrogen target. Amplitudes of the aforementioned azimuthal modulations have been extracted from part of the data. A new procedure has been developed to subtract a background coming from the decay of diffractively produced vector mesons. The results presented in this talk qualitatively agree with earlier COMPASS results obtained with an isoscalar target.
