Transverse momentum dependent nucleon structure from pions impinged on a transversely polarized proton target

Proton Structure, Nucleon Structure, Transverse Momentum Dependent, Parton Distribution

Heitz, Robert Shannon

关键词: Proton Structure, Nucleon Structure, Transverse Momentum Dependent, Parton Distribution;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/105577/HEITZ-DISSERTATION-2019.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

The transverse momentum structure of the nucleon generalizes the 1-dimensional parton distribution functions (PDFs) to a 3-dimensional description.The extended distributions are called transverse momentum dependent (TMD) parton distribution functions.TMD functions include transverse quark and gluon momentum to parameterize the non-perturbative description of a nucleon.Eight TMDs parameterize a nucleon at leading order.The Sivers TMD is special in that it is spin-dependent and theorized to change signs between the Drell-Yan process and Semi-Inclusive Deep Inelastic Scattering (SIDIS).The COMPASS spectrometer is unique in that it has the ability to measure the products from a polarized target and also because the beam can be modified to measure the SIDIS and Drell-Yan processes.The COMPASS collaboration collected transverse spin-dependent data to measure the Sivers function from SIDIS and in 2016 COMPASS published the results of a Sivers asymmetry amplitude from the SIDIS process.In 2015 COMPASS collected data to study the Drell-Yan process from a transversely polarized proton target and a 190~{\gvcw} negatively charged pion beam.Therefore COMPASS has the unique ability conclude on the non-universality of the Sivers TMD between the SIDIS and Drell-Yan processes.This thesis presents analysis of the 2015 COMPASS Drell-Yan data taking.The analysis focuses on the Sivers TMD but also provides results on the tranvsersity and pretzelosity TMD functions which are expected to be universal.The Sivers results presented in this thesis are consistent with a sign ip between Drell-Yan and SIDIS.