Recent results from the G0 experiment
oleh: Roos P., Roche J., Ramsay W.D., Quinn B., Poelker M., Pitt M.L., Pillot P., Phillips S.K., Pate S.F., Papavassiliou V., Page S.A., van Oers W.T.H., Muether M., Mkrtchyan H., Mihovilovic M., Micherdzinska A., McKeown R.D., Martin J.W., Mammei J., Lung A., Liu J., Lee L., Kox S., Korsch W., King P.M., Jones M., Horn T., Hansknecht J., Guillard G., Grames J., Gericke M.T.W., Gaskell D., Furget C., Franklin G., Flores G., Davis C.A., Ellis C., Coppens A., Chao Y.-C., Capuano C.L., Breuer H., Bosted P., Birchall J., Benmokhtar F., Bimbot L., Benesch J., Beise E.J., Beck D.H., Bailey S.L., Arvieux J., Armstrong D.S., Androić D., Real J.S., Schaub J., Seva T., Simicevic N., Smith G.R., Spayde D.T., Stutzman M., Suleiman R., Tadevosyan V., Versteegen M., Voutier E., Vulcan W., Wells S.P., Williamson S.E., Wood S.A.
| Format: | Article |
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| Diterbitkan: | EDP Sciences 2010-04-01 |
Deskripsi
We have measured parity violating asymmetries in elastic electron-proton and quasi-elastic electrondeuteron scattering at backward electron angle. These measurements have been done at two momentum transfers : Q2 = 0.22 and 0.63 (GeV/c)2 . Together with our previous forward angle measurement [1], we can extract strange quark contributions to the electromagnetic form factors of the nucleon, as well as nucleon axial form factor coming from the neutral weak interaction. The results indicate a strange quark magnetic contribution close to zero at these Q2 , and a possible non zero strange quark electric contribution for the high Q2 . The first Q2 behavior measurement of the nucleon axial form factor in elastic electron scattering shows a good agreement with radiative corrections calculated at Q2 = 0 and with a dipole form using the axial mass determined in neutrino scattering.