Measurement of High-Q2 Neutral Current Deep Inelastic e- Scattering 
 Cross Sections with a Longitudinally Polarised Electron Beam at HERA 

                 ZEUS Collaboration

                    Abstract

Measurements of the neutral current cross sections for deep inelastic 
scattering in e-p collisions at HERA with a longitudinally polarised 
electron beam are presented. The single-differential cross-sections 
dsigma/dQ^2, dsigma/dx and dsigma/dy and the double-differential 
cross sections in Q2 and x are measured in the kinematic region 
y < 0.9 and Q^2 > 185 GeV^2 for both positively and negatively 
polarised electron beams and for each polarisation state separately. 
The measurements are based on an integrated luminosity of 169.9 pb^-1 
taken with the ZEUS detector in 2005 and 2006 at a centre-of-mass energy 
of 318 GeV. The structure functions xF_3 and xF_3^{\gamma Z} are determined 
by combining the e-p results presented in this paper with previously measured 
e+p neutral current data. The asymmetry parameter A- is used to demonstrate 
the parity violating effects of electroweak interactions at large spacelike 
photon virtuality. The measurements agree well with the predictions of the 
Standard Model.