Measurements are presented of the inclusive charged-particle cross sections s dσdx for e+e− annihilation at center-of-mass energies of 5.2, 6.5, and 29.0 GeV. Significant scale breaking is observed in these cross sections.
CROSS SECTION S*D(SIG)/DX FOR CHARGED PARTICLES AT SQRT(S) = 5.2, 6.5 AND 29.0 GEV. NUMERICAL VALUES OF DATA TAKEN FROM THESIS OF J.F. PATRICK LBL-14585.
Differential cross sections for π − p and pp elastic scattering have been measured at incident momenta ranging from 30 to 345 GeV and in the t range 0.002 (GeV/ c ) 2 ⩽ | t | ⩽ 0.04 (GeV/ c ) 2 . From the analysis of the data, the ratio ϱ ( t = 0) of the real to the imaginary parts of the forward scattering amplitude was determined together with the logarithmic slope b of the diffraction cone.
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The reaction π−p→K0K−p has been measured from 50 to 175 GeV/c. The production characteristics of the A2 have been analyzed. We find spin and t dependence similar to lower energies, but the cross section falls rapidly with energy. In a Regge description of π−p→A2−p our data imply a rather small Pomeron-exchange component.
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RAW CROSS SECTION WITHIN MASS CUTS.
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The total momentum and transverse momentum spectra of electrons in e+e− annihilation at 29 GeV have been measured. The inclusive cross section is determined to be 14.4±1.6±5.2 pb for momenta greater than 2 GeV/c. The average semielectronic branching ratios of charm and bottom quarks are measured to be (6.3±1.2±2.1)% and (11.6±2.1±1.7)%, respectively. The fragmentation function for bottom quarks is determined to be peaked at high z, with 〈z〉b=0.75±0.05±0.04.
PT is the transverse momentum of the muon relative to the event thrust axis.
PT is the transverse momentum of the muon relative to the event thrust axis.
The deep-inelastic electromagnetic structure functions of deuterium and aluminum nuclei have been measured. The kinematic dependence of the ratio of aluminum and deuterium structure functions is similar to the dependence of the ratio of steel and deuterium structure functions, and provides further evidence for the distortion of the quark momentum distributions of nucleons bound in a nucleus.
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We present a summary of the physics results from an experimental study of the reaction π−p→π−π+n at 100 and 175 GeV/c incident-beam momentum. Our data show the continuing dominance of one-pion exchange in these reactions with the characteristic 1Plab2 momentum dependence. We extract the pion Regge trajectory from our data on π−p→ρ0n and study the zero structure of the ππ differential cross section up to sππ=12 GeV2.
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SPHERICAL HARMONIC MOMENTS.
The differential cross sections for lepton pair production in e+e− annihilation at 29 GeV have been measured and found to be in good agreement with the standard model of the electroweak interaction. With the assumption of e−μ−τ universality, the weak neutral-current couplings are determined to be ga2=0.23±0.05 and gv2=0.03±0.04.
Numerical values supplied by M.Levi.
Data requested from authors.
Extrapolated to full angular range.
We have studied several features of the production of charged-hardon pairs by γγ collisions. We have measured the f0 partial width Γf0→γγ(Q2) for Q2 in the range 0<Q2<1.4 GeV2/c2, and obtained Γf0→γγ=2.52±0.13±0.38 keV at Q2≈0. The measured Q2 dependence is in agreement with the generalized vector-dominance model. The cross section for γγ→(π+π−+K+K−) in the mass region 1.6≤Mππ≤2.5 GeV/c2 has also been measured and the result compared with that expected from the QCD continuum.
Data read from graph.. Both statistical and systematic errors included.
A search for single electrons from the decay of singly produced scalar electrons has been made at the PEP storage ring at SLAC. No events of this type have been found in 123 pb−1 of data, resulting in a cross-section limit of less than 2.4×10−2 pb within the detector acceptance, and a 95%-confidence-level lower limit on the scalar-electron mass of 22.2 GeV/c2.
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We have studied D* production mechanisms using data from a photoproduction experiment at the Fermilab Tagged Photon Spectrometer. A large sample of charged D*’s was selected via the clean signature of the cascade decay D*→D0π+ and subsequently D0→K−π+ or D0→K−π+π0. The cross section for the process γp→(D*++anything)p at an average energy of 105 GeV was measured to be 88±32 nb. Only (11±7)% of D*’s were found to be consistent with being accompanied solely by a D¯* or a D¯; the remaining events contain additional particles. The distribution of the production angle of the D* in the photon-fragmentation-system center of mass is strongly anisotropic and consistent with the form f(θ*)=cos4θ*. We set a limit on the associated-production-process cross section σ(γp→(D¯*−+anything)Λc) x)<60 nb (90% C.L.).
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