First observation of a dip at t=-14 (GeV/c)/sup 2/ in pp differential elastic cross section at 50 GeV/c

Summary form only given, as follows. Preliminary results of the CERN WA7 collaboration concerning the pp elastic differential cross-section measurements at 50 GeV/c are presented. The t-range covered extends from -.7 to -5. (GeV/c)/sup 2/. The set-up is an extended version of the arrangement used at very large t in pi /sup +or-/p. The results are shown in a figure. The overall normalization is not yet finished. A clean dip-bump structure is observed with a pronounced minimum at t =-1.4 (GeV/c)/sup 2/. This dip could possibly be of the same origin as the one seen in pp scattering at a similar t-value and for the same value of the total cross-section. Different models based on the geometrical pictures or multiple quark mechanism could describe these data. (7 refs).