At the borderline between exclusive and inclusive physics: Study of Drell-Yan fragments in the PANDA experiment (A preliminary simulation)

Abstract

Here a preliminary study is presented concerning the detection of the normally unseen Drell-Yan fragments, possible in the PANDA experiment. To work as a multi-purpose apparatus, this experiment will record all the particles produced in the collisions between the antiproton beam and the target, with a rather wide acceptance. So detecting Drell-Yan dileptons with or without analyzing the other fragments is just a matter of applying cutoffs in the data analysis stage. The distribution of the products of 50,000 typical Drell-Yan events is here simulateded using a well-known generator code (Pythia-8). The resulting distributions are inserted within the PANDA acceptance region, to analyze the chances of missing some searched fragment combinations, or of confusing different sets of particles. The most interesting result is that, due to the reduced phase space, the produced states are much simpler than one could imagine: (i) almost 50 % of the events just consist of a dilepton plus a nucleon-antinucleon pair; (ii) practically all events present a nucleon-antinucleon pair; (iii) the number of light particles (photons over an infrared cutoff and pions) is pretty small. The presented simulations show that it is possible to study experimentally some, or some aspects, of the most relevant final states, with good statistics and precision.