Proton-proton elastic scattering using 201- and 400-GeV/c extracted beams at Fermilab has been measured in the region 4.9<−t<14.4 GeV2. Contrary to predictions of diffraction models, there is no sign of a second dip or "break," and the slope A in the fit exp(At) is smaller than predicted. It drops from 1.5 to 0.8 GeV−2 over our t range. The shape of the t distribution can be fitted by the power law dσdt∝t−8.4 which is close to a quantum-chromodynamics (QCD) prediction of t−8. At fixed t the 201-GeV/c cross sections are about 2.3 times those at 400 GeV/c which is compatible with the QCD and constituent-interchange-model prediction that dσdt∝s−10 at fixed ts.
LOW T.
HIGH T.
LOW T.
We have studied transverse momenta of charged hadrons in the current fragmentation region of charged current antineutrino- nucleon interactions observed in the Fermilab 15 ft bubble chamber. The measured momentum squared transverse to the v μ + plane (p out 2 ) of the negative hadrons varies as a function of Q 2 , W 2 and x as expected from t he leading order perturbative QCD calculations. Positively charged hadrons show a different transverse momentum behaviour as a function of Q 2 .
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The reaction π − p↑→ π − π + π − p has been measured at 17 GeV/ c using a polarized target. The data sample contains about 60 000 interactions on polarized protons. The nucleon polarization as a function of momentum transfer is very similar to elastic π − p scattering and is nearly independent of the π mass, except for a possible structure around 1.2 GeV.
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The transverse momenta of charged hadrons produced in high energy muon-proton scattering have been studied. The average squared transverse momentum 〈 p 2 ⊥ 〉 shows a strong dependence on z = E h / v characteristic of intrinsic momentum effects and a significant rise as a function of s = W 2 . The W 2 , q 2 , x and z dependences of the data are compared with the predictions of a perturbative QCD model.
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Additional systematic uncertainty 25% not included.
Measurements of the charged multiplicities for hadron production in e + e − annihilation in the center of mass energy range 9–32 GeV have been made. The average charged multiplicity has an energy dependence much stronger than ln s and similar to that reported for pp collisions. Quantitative differences are observed in the magnitude of both the average multiplicity 〈 n ch 〉 and the dispersion D ch for e + e − and pp interactions at the same center of mass energy. 〈 n ch 〉 and the ratio 〈 n ch / D ch in e + e − annihilations are significantly larger than in pp collisions and are found to be in overall agreement with QCD predictions. KNO scaling is seen to be satisfied.
THE FINAL TABLE ENTRY COMBINES THE DATA FROM THE THREE HIGHEST ENERGY BINS.
The polarization parameter for K + n charge exchange scattering has been measured at five momenta between 0.851 GeV/ c and 1.351 GeV/ c for centre of mass angles −0.8 < cos θ ∗ < 0.8 . Results from a phase shift analysis incorporating these results are presented. No Z ∗ resonances are observed.
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The total cross section fore+e− annihilation into hadrons for center of mass energies from 9.4 to 9.5 GeV has been measured with the nonmagnetic DESY-Heidelberg detector at DORIS. A value ofR=σhad/σµµ=3.8±0.7 for the continuum region around the Υ (9.46) resonance has been determined. The ratioΓeeΓhad/Γtot of electronic, hadronic and total widths has been reevaluated to be (1.00±0.23) keV for the Υ resonance and (0.37±0.16) keV for the Υ′. In addition, a search for directly produced pohotons from Υ decays of the type Υ→γ+gluon+gluon has been performed. The Υ decay into muon pairs has also been searched for.
TOTAL CROSS SECTION FOR THE CONTINUUM REGIONS AROUND THE UPSI(9460)0 AND UPSI(10020)0 RESONANCES.
We have measured 618 K + p → π + K S 0 p events at 12.7 GeV/ c incident lab momentum, mass range 790 ⩽ m π + K s 0 ⩽ 990 MeV and t range 0.01 ⩽ − t ⩽ 0.60 (GeV/ c ) 2 . The π + K S 0 mass spectrum is dominated by the K ∗+ (892) resonance and a Breit-Wigner fit yields a mass m = 893.5 ± 1.1 MeV and a width Γ = 33.2 ± 4.1 MeV which is much narrower than measured hitherto. The t distribution of K ∗+ (892) events shows a dip in the forward direction and an exponential fall off thereafter, consistent with dominance of helicity flip amplitudes. The spin density matrix is almost saturated by ρ 11 and ρ 1−1 which are very close to their maximum allowed value of 1 2 throughout the measured t range except in the very forward direction where ρ 00 and Re ρ 10 deviate from zero. Natural parity exchanges, therefore, dominate with unnatural parity exchanges being restricted to a small region in the forward direction. A Regge pole analysis of the differential cross sections of the present measurement in conjunction with previously measured total cross sections supports the f-coupled-pomeron hypothesis.
SUBTRACTED BACKGROUND IS PHASE SPACE.
SUBTRACTED BACKGROUND IS AN INCOHERENT S-WAVE WITH EXPONENTIAL T-DEPENDENCE WITH SLOPE OF 6 GEV**-2.
Axis error includes +- 15/15 contribution.
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