Six "beyond Collins and Sivers" transverse spin asymmetries at COMPASS

Abstract

COMPASS is a fixed-target high energy physics experiment at the SPS at CERN \cite{Abbon:2007pq}. One of the important objectives of the experiment is the exploration of the transverse spin structure of the nucleon via spin dependent azimuthal asymmetries in single-hadron production in deep inelastic scattering of polarized leptons off transversely polarized target. For this purpose a series of measurements were made in COMPASS, using 160 GeV/c longitudinally polarized muon beam and transversely polarized ${}^{6}LiD$ (in 2002, 2003 and 2004) and $N{H}_3$ (in 2007 and 2010) targets. Till now main attention was focused on Collins and Sivers asymmetries and obtained results play an important role in the general understanding of the three-dimensional nature of the nucleon in terms of Transverse Momentum Dependent (TMD) Parton Distribution Functions (PDFs) and Fragmentation Functions (FFs). In addition to these two measured leading-twist effects, the SIDIS cross-section counts six more target transverse spin dependent azimuthal effects, which have their own well defined leading or higher-twist interpretation in terms of QCD parton model. So far COMPASS presented preliminary results for these asymmetries from deuteron \cite{Parsamyan:2007ju},\cite{Kotzinian:2007uv} and "proton-2007" data \cite{Parsamyan:2010se}. In this contribution we review the results obtained with the last "proton-2010" data sample.

Contribution given at the 20th International Symposium on Spin Physics (SPIN2012) JINR, Dubna, Russia, September 17 - 22, 2012. To be published in "Physics of Elementary Particles and Atomic Nuclei" review journal

References in corpus (6)

• The COMPASS Experiment at CERN
• Experimental investigation of transverse spin asymmetries in muon-p SIDIS processes: Sivers asymmetries
• Experimental investigation of transverse spin asymmetries in muon-p SIDIS processes: Collins asymmetries
• Azimuthal spin asymmetries in light-cone constituent quark models
• Predictions for double spin asymmetry A_{LT} in Semi Inclusive DIS
• Transverse momentum dependence of the quark helicity distributions and the Cahn effect in double-spin asymmetry $A_{LL}$ in Semi Inclusive DIS

Cited by in corpus (11)

• First measurement of transverse-spin-dependent azimuthal asymmetries in the Drell-Yan process
• Sivers asymmetry extracted in SIDIS at the hard scale of the Drell-Yan process at COMPASS
• Transverse-momentum dependent parton distribution functions beyond leading twist in quark models
• Transverse spin effects in hard semi-inclusive collisions
• Extraction of the distribution function $h_{1T}^{\perp }$ from experimental data
• Transverse single-spin asymmetries of pion production in semi-inclusive DIS at subleading twist
• Double Spin Asymmetries $A_{LT}^{\cos {\varphi }_S}$ and $A_{LT}^{\cos (2{\varphi }_h-{\varphi }_S)}$ in semi-inclusive DIS
• Transverse spin azimuthal asymmetries in SIDIS at COMPASS: Multidimensional analysis
• New results on transverse spin asymmetries from COMPASS
• SIDIS transverse spin azimuthal asymmetries at COMPASS: Multidimensional analysis
• Polarized Drell-Yan at COMPASS-II: Transverse Spin Physics Program