Two studies in QCD

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:5117137

Milana, J P

Two investigations in quantum chromodynamics are presented. The first, entitled Factorization at low x, is a study in perturbative QCD of high energy hadron-hadron collisions using the double log approximation to probe new, hitherto unstudied, kinematic regions. The reaction proceeds via a parton from hadron one (with a fraction of the hadron's momentum x{sub 1}, and probability of being in the hadron, F{sub 1}) colliding with a parton from hadron two (with momentum fraction x{sub 2} an structure function F{sub 2}). The new regions of study are those in which one momentum fraction is much larger than the other (i.e. x{sub 1} >> x{sub 2}, or x{sub 2} >> x{sub 1}). New processes, involving soft gluons, are identified and an estimate for their contribution to the cross-section is given. Although involving soft gluons, it is seen these processes nevertheless preserve factorization as they can be incorporated into a redefinition of one of the structure functions (F{sub 2} or F{sub 1} respectively). The second study, Gluons in the Chiral Bag, is a perturbative QCD calculation, using cavity quantum chromodynamics, of gluon exchange corrections to the cranking moment of inertia of the chiral bag model (CBM). Cranking (the introduction of a slowly rotating, quantized collective motion) is needed to construct the nucleon and delta states in the CBM. By fitting the empirical {Delta} - N mass splitting a value of the effective strong coupling is extracted. It is found that when the bag is small (R < 0.5 fm), the nucleon-delta mass splitting is adequately described without including any gluon corrections. For larger bag radii, (i.e. R = 1 fm) the size of the coupling constant ({alpha}{sub c} = 0.6) thus extraced compares favorably with the MIT coupling ({alpha}{sub c} = 0.055)t represents no true improvement.

• Research Organization: State Univ. of New York, Stony Brook, NY (USA)
• OSTI ID: 5117137
• Country of Publication: United States
• Language: English

Related Subjects

645400 -- High Energy Physics-- Field Theory
653000 -- Nuclear Theory
657000* -- Theoretical &amp; Mathematical Physics
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BAG MODEL
BOSONS
CALCULATION METHODS
COMPOSITE MODELS
ELEMENTARY PARTICLES
EXTENDED PARTICLE MODEL
FIELD THEORIES
GLUONS
HADRON-HADRON INTERACTIONS
INTERACTIONS
MATHEMATICAL MODELS
NUCLEAR MODELS
PARTICLE INTERACTIONS
PARTICLE MODELS
PERTURBATION THEORY
POSTULATED PARTICLES
QUANTUM CHROMODYNAMICS
QUANTUM FIELD THEORY
QUARK MODEL