Nucleon spin structure studies at COMPASS: recent results and prospects

Jul 19, 2022, 10:40 AM
Classroom 512 (APCTP)

Classroom 512


Asia Pacific Center for Theoretical Physics, Pohang, Gyeongbuk 37673, Korea


Bakur Parsamyan (CERN, Turin section of INFN)


Nucleon spin structure studies at COMPASS: recent results and prospects COMPASS is a fixed target high energy physics experiment located at the M2 beamline (SPS, North Area) at CERN. The experiment is collecting data since 2002 covering a broad range of physics topics. Experimental results obtained by COMPASS during phase-I (2002-2011) for spin (in)dependent azimuthal azimuthal effects in semi-inclusive deep inelastic scattering (SIDIS) measurements, play an important role in the general understanding of the three-dimensional nature of the nucleon. Giving access to the entire “twist-2” set of transverse momentum dependent (TMD) parton distribution functions (PDFs) and fragmentation functions (FFs), COMPASS data triggers constant theoretical interest and are being widely used in phenomenological analyses and global data fits.

In 2015 and 2018 COMPASS performed measurements of the Sivers and other transverse azimuthal asymmetries in Drell-Yan process. Those measurements serve as a complementary input to the TMD studies. Combined with existing SIDIS data, they provide a unique possibility to study the nucleon spin-structure using an alternative channel and to test predicted in QCD (pseudo-)universal features of the TMD PDFs.
In 2022 COMPASS is going to accomplish the series of measurements performed in phase-I using 190 GeV/c muon beam and polarized targets, by collecting largest ever sample of SIDIS events with transversely polarized deuteron. This last round of measurements is particularly important for constraining the d-quark transversity and other TMD PDFs
In this talk COMPASS SIDIS and Drell-Yan results on azimuthal asymmetries, obtained from transversely polarized deuteron and proton data will be reviewed along with relevant phenomenological studies and global fits. The details on COMPASS 2022 data-taking will be presented.

Primary author

Bakur Parsamyan (CERN, Turin section of INFN)

Presentation materials