First Measurement of Transverse-Spin-Dependent Azimuthal Asymmetries in the Drell-Yan Process

(COMPASS Collaboration)

Research output: Contribution to journalArticlepeer-review


The first measurement of transverse-spin-dependent azimuthal asymmetries in the pion-induced Drell-Yan (DY) process is reported. We use the CERN SPS 190 GeV/c π- beam and a transversely polarized ammonia target. Three azimuthal asymmetries giving access to different transverse-momentum-dependent (TMD) parton distribution functions (PDFs) are extracted using dimuon events with invariant mass between 4.3 GeV/c2 and 8.5 GeV/c2. Within the experimental uncertainties, the observed sign of the Sivers asymmetry is found to be consistent with the fundamental prediction of quantum chromodynamics (QCD) that the Sivers TMD PDFs extracted from DY have a sign opposite to the one extracted from semi-inclusive deep-inelastic scattering (SIDIS) data. We present two other asymmetries originating from the pion Boer-Mulders TMD PDFs convoluted with either the nucleon transversity or pretzelosity TMD PDFs. A recent COMPASS SIDIS measurement was obtained at a hard scale comparable to that of these DY results. This opens the way for possible tests of fundamental QCD universality predictions.

Original languageEnglish (US)
Article number112002
JournalPhysical review letters
Issue number11
StatePublished - Sep 12 2017

ASJC Scopus subject areas

  • Physics and Astronomy(all)


Dive into the research topics of 'First Measurement of Transverse-Spin-Dependent Azimuthal Asymmetries in the Drell-Yan Process'. Together they form a unique fingerprint.

Cite this