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Title: Azimuthal asymmetry and transverse momentum of hadrons in deep inelastic muon scattering at 490 GeV

Miscellaneous ·
OSTI ID:6909544

The forward charged hadrons produced in deep inelastic scattering of 490 GeV muons from deuterium were studied. The data were taken by the E665 collaboration during the 1987-1988 Fermilab fixed target run. 3 [times] 10[sup 4] Events (6 [times] 10[sup 4] hadrons) were collected over a large range of kinematic variables: 100 GeV < [nu] < 500 GeV, 2 GeV[sup 2] < Q[sup 2] < 100 GeV[sup 2], 0.003 < x[sub Bj] < 0.2, and 0.2 < y[sub Bj] < 0.9. Using the virtual photon axis as the z-axis, the distributions of the produced hadrons in azimuthal angle and in transverse momentum are examined. The primordial k[perpendicular] of the struck patron and O([alpha][sub s]) QCD effects are expected to contribute to an azimuthal asymmetry and to an increase in the average transverse momentum. Some theoretical work in the literature concerning these effects is described and some original results are derived concerning the effects of primordial k[perpendicular] on the azimuthal distribution. A Monte Carlo program is described which includes these theoretical effects and models fragmentation, the detector response, and the event reconstruction. The data exhibit several surprising effects. First, the phi asymmetry in the data is independent of Q[sup 2], while theoretically it should be more pronounced at low Q[sup 2] and vanish at high Q[sup 2]. Second, the phi asymmetry is carried by the most energetic particle in each event, which the author calls the Rank 1 particle, and there is very little phi asymmetry of the other charged hadrons. Third, the phi asymmetry in the Rank 1 particle is independent of the hadron energy fraction z[sub h]. The Monte Carlo predicts a strong z[sub h] dependence and little rank dependence. Finally, the seagull plot shows an unexpected increase in transverse momentum p[sub T] for high energy hadrons (z[sub h] > 0.4) as a function of Q[sup 2].

Research Organization:
Massachusetts Inst. of Tech., Cambridge, MA (United States)
OSTI ID:
6909544
Resource Relation:
Other Information: Thesis (Ph.D.)
Country of Publication:
United States
Language:
English