Subjet Multiplicity of Quark and Gluon Jets Reconstructed with the K̳ Algorithm in P−p Collisions
Author: Robert Michael Snihur
Publisher:
Published: 2000
Total Pages:
ISBN-13:
DOWNLOAD EBOOKThis thesis presents some of the first experimental results of the k⊥ jet algorithm at a hadron collider. Gluon jets dominate the final state of proton-antiproton (pp¯) collisions at high center-of-mass energies ( s = 1800 GeV). Quark jets make up a significant fraction of the jet cross section only at high jet transverse momentum pT or low s . For fixed pT, we compare jets at s = 1800 GeV to s = 630 GeV, and interpret differences in terms of differing contributions from gluon and quark jets. We define jets with a successive combination algorithm based on relative transverse momenta ( k⊥ ). To study jet structure, the k⊥ algorithm is then applied within the jet to resolve subjets. We measure the number of subjets within mixed quark and gluon jet samples at s = 1800 and 630 GeV. A simple method is used to extract measurements of pure quark and gluon jet samples separately. The method requires knowledge of the relative mix of quarks and gluons in the two s samples, which we derive from Monte Carlo and a detailed detector simulation. The number of subjets emitted in gluon jets is measured to be approximately twice that in quark jets.