Measurements of tensor analyzing power T20 in reactions p (d,p) d and p (d,p) pn at 0 deg for incident deuteron momenta between 3.5 - 6.5 GeV/c

The tensor analyzing power T20 for the p (d,p) d and p (d,p) pn reactions at 0 deg (θcmp = 180 deg) have been measured at incident momenta from 3.5 to 6.5 GeV/c. For both reactions T20 remains negative up to 6.5 GeV/c (that corresponds to the internal momentum k≅0.85 GeV/c, defined in the light front system). This situation completely contradicts the standard one nucleon exchange model prediction. A new structure in the dependence of T20 on k≅0.65 GeV/c is observed .The first measured values of T20 for deuteron breakup without pion production differ at the same k both from data on T20 for the backward elastic scattering and from data on T20 for deuteron breakup in the region where pion production is allowed. An evidence has been obtained on a 'quasiresonance' enhancement of differential cross section close to the kinematical limit of the p(d,p)pn reaction. New data on T20 for the p(d,d') X reaction in the region of MX from 1.46 to 1.62 GeV/c2 have been obtained simultaneously. (author)