Beam Jet Structures in Soft and Hard Proton-Proton Collisions at SQRT.S = 27.4 GEV
Abstract
In this thesis we study the beam jet structures in soft and hard proton-proton collisions at SQRT.(s) = 27/4 GeV using charged par- ticles. Data were taken using Fermilab Multiparticle Spectrometer. triggered by a highly segmented calorimeter with (DELTA)(phi) = 2(pi) and 45(DEGREES) <(, )(THETA)* <(, )125(DEGREES). The study of soft and hard collisions is done by. scanning transverse energy(E(,t)) in the calorimeter from 1 to 20 GeV whose corresponding x(,T)(=E(,t)/SQRT.(s)) ranges from 0.05 to 0.7. We find: for high E(,t)(>8 GeV) events, excessively soft beam fragmen- tation compared to the prediction of ISAJET model: E(,t) scaling of. beam fragmentation for negative particles and its violation for positive ones: at high E(,t), E(,t) scaling of beam fragmentation for both charges, and the approximately constant ratio (=1.73 (+OR-) 0.15) of the beam fragmentation function of positive particle to that of negative. ones at large x'(=2P(,z)*/(SQRT.(s)-E(,t))): disappearance of the leading proton effect in the beam jet core. By comparison to (nu)((nu))p data, we demonstrate a transition from diquark to single quark nature of the beam remnant, which amounts to the breakdown of 4-jet structure in high E(,t) pp-collision; this breakdown is qualitatively consistent with. multiple pairs of 2 (--->) 2 subprocesses. Also studied are correlations of 90(DEGREES) jet and the beam jet using the "planarity" as a measure of 90(DEGREES) jet. We divide events into high and low planarity events at planarity P = 0.7 to designate jet and non-jet events. For high planarity events,. we find the harder beam fragmentation and larger net charged energy flow. Positive particles are harder in high planarity events than in low planarity ones, and probably they are leading particles.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 1986
- Bibcode:
- 1986PhDT........60A
- Keywords:
-
- BEAM FRAGMENTATION;
- MULTIPLE PARTON SCATTERING;
- PLANARITY;
- Physics: Elementary Particles and High Energy