The spin structure of the proton at low x and low Q2 in two-dimensional grids from COMPASS

Apr 13, 2016, 11:20 AM
SR4a (DESY Hamburg)


DESY Hamburg

Spin Physics WG6 Spin Physics


Ana Sofia Nunes (LIP-Lisbon)


The longitudinal double spin asymmetries A1p and the spin dependent structure function of the proton g1p were extracted from COMPASS data in the region of low x and low Q2. The data were taken on 2007 and 2011 from scattering of polarised muons off polarised protons, resulting in a sample that is 150 times larger than the one from the previous experiment SMC that pioneered searches in this kinematic region. For the first time, A1p and g1p were evaluated in this region in two-dimensional grids of kinematic variables: (x,Q2), (ν,Q2), (x,ν) and (Q2,x). The following kinematic region was investigated: 4.0x10-5<x<4.0x10-2, 0.001<Q2<1 (GeV/c)2 and 14<ν<194 GeV. The obtained results can be confronted with theoretical models.

Primary author

Ana Sofia Nunes (LIP-Lisbon)

Presentation materials