New target transverse spin dependent azimuthal asymmetries from COMPASS experiment

Understand

In general, eight target transverse spin-dependent azimuthal modulations are allowed in semi inclusive deep inelastic scattering of polarized leptons on a transversely polarized target.

• In the QCD parton model four of these asymmetries can be interpreted within the leading order approach.
• Two of them, namely Collins and Sivers effects were already measured by HERMES and COMPASS experiments.
• Other two leading twist and remaining four azimuthal asymmetries which can be interpreted as twist-three contributions have been measured for the first time in COMPASS using a 160 GeV/c longitudinally polarized ($P_{beam}\simeq -0.8$) muon beam and a transversely polarized $^6LiD$ target.