Production of proton-antiproton pairs by two-photon scattering has been observed at the electron-position storage ring PETRA. A total of eight proton-antiproton pairs have been identified using the time-of-flight technique. We have measured a total cross section of 4.5 ± 0.8 nb in the photon-photon c.m. energy range 2.0–2.6 GeV.
No description provided.
The inclusive cross section for the production ofKs0 mesons, Λ and\(\bar \Lambda\) particles in proton-proton interactions at\(\sqrt s= 63\) GeV is presented. The produced particles have been detected in the full phase space. Behaviour of the longitudinal and transversal depandences of the cross sections are discussed. The total production cross sections fors0 mesons and Λ particles was determined to\(\sigma _{{\rm K}_S^0 }= (25.5 \pm 1.4)\) mb andσΛ=(7.8±1.2) mb respectively. A strong energy dependence of the production cross sections is observed.
THE SIG(KS) ERROR INCLUDES THE UNCERTAINTY OF THE NORMALIZATION AND THE PT EXTRAPOLATION.
No description provided.
No description provided.
The small-angle elastic scattering for pp at s=23.5, 30.7, and 52.8 GeV and for p¯p at s=52.8 GeV are measured. The data are normalized on Coulomb scattering. Using the optical theorem and the best estimate of the real part of the forward scattering amplitude, ρ(pp¯)=0.1, we obtain σtot(p¯p)=44.1±2.9 mb for the total cross section and b(p¯p)=13.6±2.2 GeV−2 for the nuclear slope parameter. This supports the dispersion relation prediction that σtot(p¯p) will start to rise above Elab≈200 GeV.
No description provided.
No description provided.
No description provided.
Measurements of pp→μ+μ−+X at s=44 and 62 GeV are compared. The data are taken under identical conditions utilizing clean proton-proton collisions from the CERN intersecting storage rings and confirm scaling to 5%. The observed μ+μ− yield is a factor of 1.6±0.2 larger than estimated from a simple parton model but is consistent with QCD. The pT dependence of the muon pairs agrees well with expectations from QCD.
No description provided.
None
No description provided.
No description provided.
No description provided.
None
No description provided.
No description provided.
Data are given for the polarization parameter and for the differential cross section in pp elastic scattering at 200 GeV/ c , in the range 0.5 ⪕−t ⪕ 4.0 GeV 2 . The polarization changes sign in the dip region, as already observed at 150 GeV/ c .
No description provided.
No description provided.
The proton structure function F 2 has been measured in the range 2.5 ⪕ Q 2 ⪕ 170 GeV 2 and 0.03 ⪕ x ⪕ 0.65 . Scaling violation is clearly seen in the data. Results of fits to leading-order QCD are presented, together with values of the scale-breaking parameter λ.
No description provided.
No description provided.
No description provided.
A measurement of the nucleon structure function F 2 on iron is presented. The data cover a kinematic range of 3.25 ⪕ Q 2 ⪕ 200 GeV 2 and 0.05 ⪕ x ⪕ 0.65 . The data clearly show scaling violation. Fits in leading-order QCD have been made and values for the scale breaking parameter λ are given.
No description provided.
No description provided.
No description provided.
Inclusive ρ 0 production in neutrino-proton charged-current interactions is studied, using a sample of 7831 events obtained in BEBC filled with hydrogen and exposed to the CERN wideband neutrino beam. An average multiplicity of 0.14±0.02 ρ 0 per event is found, corresponding to a ratio 〈 ρ 0 〉/〈 π − 〉=0.13±0.02. The ρ 0 production characteristics are determined as functions of leptonic variables ( W , Q 2 , χ B ) and hadronic variables ( χ F , z , p t 2 ) and are found to be similar to those determined for hadron- and other lepton-induced reactions.
No description provided.
No description provided.
No description provided.
Forum