Charged Particle Pseudorapidity Distributions in Minimum Bias and Intermediate Vector Boson Events at $$\sqrt{s}$$ = 1800 GeV
- Chicago U.
We present measurements of the pseudo-rapidity (1J = In(tan({//2)), where (/ is the polar angle in the lab frame) distribution of charged particles (dNch / d1J) produced within 11J1 ~ 3.5 in proton-antiproton collisions at J8 of 630 and 1800 GeV. We measure dNch/d1J at 1J = 0 to be 3.18±0.06(stat)±0.10(sys) at 630 GeV, and 3.95±0.03(stat)±0.13(sys) at 1800 GeV. Some systematic errors in the ratio of dNch/d1J at the two energies cancel, and we measure 1.26±0.01±0.04 for the ratio of dNch /d1J at 1800 GeV to that at 630 GeV within 11J1 ~ 3. Comparing to lower energy data, we observe an increase in dNch/d1J at 1J = 0 that is faster than In(s). We also measure the ratio of dNch/d1J for charged particles produced in events in which an intermediate vector boson is observed in the decay channel W± -e±v or ZO _ e+e-to that in minimum bias events as a function of the boson Pt. The absence of strongly interacting particles in the boson final state allows an unambiguous separation of the particles produced by the spectator system from those of the hard parton-parton collision. We find that at Pt = 0, the ratio averaged within 11J1 < 3 is 1.22±0.08±0.12 in W events, and 1.31±0.21±0.11 in Z events, indicating that particle production by the spectator system in hard collisions is very similar to that in minimum bias events, with only a slight enhancement. These results do not support predictions for these quantities based upon two models of minimum bias particle production, including the Dual Parton Model and a simple impact parameter model. We observe an increase of about 20% over similar results reported by the UA1 collaboration at 630 GeV. xiii
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- DOE Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1426715
- Report Number(s):
- FERMILAB-THESIS-1990-12; 312427
- Country of Publication:
- United States
- Language:
- English
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