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PT(P=3,NAME=OUT)**2 - MEAN SQUARE OF THE PROJECTION OF THE ASSOCIATED PARTICLE TRANSVERSE MOMENTUM ONTO THE NORMAL TO THE TRIGGER PARTICLE PRODUCTION PLANE.
Measurements of the partial charge-changing cross sections for the fragmentation of relativistic iron, lanthanum, holmium, and gold nuclei of several different energies incident on targets of polyethylene, carbon, aluminum, and copper have been reported in an accompanying paper. This paper describes the systematics of the variations of these cross sections with energy, projectile, target, and fragment. We have been able to generate a seven-parameter global fit to 795 measured cross sections for the heavy targets which fits the data with a standard deviation of 7%. We have also generated a similar global fit to 303 measured cross sections for a hydrogen target which fits the data with a standard deviation of 10%. These representations imply that the hypothesis of limiting fragmentation is only accurate to some 20–30 %. Weak factorization can apply, but fits that are marginally better, and more physically plausible, can be obtained without factorization. We have identified, and discussed, a number of caveats to the applicability of these fits outside, and inside, the range of energies and masses covered. Excessively large cross sections for the loss of a single proton from the projectile nuclei suggest electromagnetic dissociation. The cross sections for fragments that experience large charge changes appear to become independent of the size of the charge change. Very heavy projectiles have a significant probability of experiencing fission.
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(1/N)*D(N)/D(P) HAS BEEN FITTED BY (P/MEAN(N=P))**POWER* EXP(-SLOPE*SQRT(P/MEAN(N=P))).
Fermilab experiment 711 has investigated proton-nucleus collisions in which two high-transverse-momentum hadrons are produced forming high-mass ++, +-, and -- charged states, using an 800-GeV/c proton beam on targets of beryllium, aluminum, iron, and tungsten. Our data cover the range in dihadron mass from 6 to 15 GeV/c2. We show here that the dependence of the cross section on atomic weight A can be parametrized as Aα where α=1.043±0.011(stat)±0.025 (syst), and is independent of the charge state of the dihadron system.
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Calorimeter measurements of dσ de t for pp, dd, pα , and αα collisions at S nn =31.5 GeV are presented for the pseudorapidity interval | η cm | ⩽ 0.7, extending over eight decades to E t ⩾ 30 GeV. The data are compared with models that predict nuclear cross sections directly from pp data, under the assumption of independent nucleon scatters.
The distributions are fitted D(SIG)/D(ET)=CONST*ET**POWER*EXP(-SLOPE*ET).
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INDEPENDENTLY OF THE NUMBER OF PI0 PRODUCED IN THE REACTION.
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AUTHORS FIT D2(SIG)/D(XL)/D(PT**2) BY (1-XL)**POWER*EXP(-SLOPE*PT**2).
AUTHORS FIT D2(SIG)/D(XL)/D(PT**2) BY (1-XL)**POWER*EXP(-SLOPE*PT**2).
AUTHORS FIT D2(SIG)/D(XL)/D(PT**2) BY (1-XL)**POWER*EXP(-SLOPE*PT**2).
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THE BETTER FIT FOR PI- AND BARIONBAR IS THE SUM OF TWO EXPONENT: A*EXP(-B1*PT**2)+D*EXP(-B2*PT**2).FOR PI- B1=30+-4 AND B2=6.3+-.3 .FOR BARIONBAR B1=46+-18 AND B2=3.9+-.5.
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The production of the Jψ resonance in 125-GeV/c p¯ and φ− interactions with Be, Cu, and W targets has been measured. The cross section per nucleon for Jψ production is suppressed in W interactions relative to the lighter targets, especially at large values of Feynman x, which is opposite to the expectation from the various explanations of the European Muon Collaboration effect. Models incorporating modifications of the gluon structure functions in heavy targets show qualitative agreement with the data.
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Results of fitting the differential distributions in x F and p T 2 of D mesons produced in 400 GeV/ c p-p interactions to the form d 2 σ d x F d p T 2 ∝(1−x F ) n exp [−(p T 2 /〈p T 2 〉)] are discussed. The D + distribution is found to be relatively hard [ n =3.1±0.8〈 P t 2 〉=1.32±0.27 (GeV/ c ) 2 ] and the D̄ 0 distribution relatively soft [ n =8.1±1.9,〈 p T 2 〉=0.62±0.14 (GeV/ c ) 2 ] compared to the average for all D's [ n =4.9±0.5,〈 p T 2 〉=0.99±0.10 (GeV/ c ) 2 ]. It is suggested that these distributions could reflect contribution of leading di-quarks in pp collisions. Comparison is made with evidence for leading quarks in charm production in 360 GeV/ cπ − p interactions.
The invariant (C=INV) and non-invariant (C=NON-INV) distributions are fitted to (1-XL)**POWER. Pt distribution is fitted to EXP(-PT**2/SLOPE).
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