Light Quark Photoproduction at Fermilab

Abstract

This analysis is based on approximately 900,000 quasi-exclusive π⁺ π^- pairs recorded with the E687 spectrometer during the 1990/91 fixed target runs [1] at high energy (7.5 < $\sqrt s$ < 17.0). Exclusive final states are selected based on the total number of charged tracks seen in the spectrometer and by requiring no visible energy in our electromagnetic calorimeters. Most of the data (≈98%) has been taken with a Beryllium target (a small part of the date were taken with A1 and Pb targets to prove that our samples are indeed diffractive by relating the highest t-slope to the size of the nucleus).