Measurement of high-Q2 charged current deep inelastic scattering cross sections 
              with a longitudinally polarised positron beam at HERA

                        ZEUS Collaboration

                              Abstract

Measurements of the cross sections for charged current deep inelastic 
scattering in e+p collisions with a longitudinally polarised positron beam 
are presented. The measurements are based on a data sample with an 
integrated luminosity of 132 pb-1 collected with the ZEUS detector at HERA 
in 2006 and 2007 at a centre-of-mass energy of 318 GeV. The total cross 
section is presented at positive and negative values of the longitudinal 
polarisation of the positron beams. The single-differential cross sections 
dsigma/dQ2, dsigma/dx and dsigma/dy are presented for Q2 > 200 GeV2. The 
reduced double-differential cross section is presented in the kinematic range 
280 < Q2 < 30 000 GeV2 and 0.0078 < x < 0.42. The cross section 
measurements agree well with the predictions of the Standard Model. In 
addition, a linear fit is applied to the total cross section as a function 
of polarisation. The fit is extrapolated to determine the upper limit on 
the cross section for a fully left-handed positron beam. The lower limit 
on the mass of a hypothetical W boson which couples to right-handed 
particles is then extracted.