Interactions between 4.15-Bev protons and the free hydrogen nuclei in nuclear emulsion are examined. The total elastic cross section from 27 events was determined to be 11.0±2.6 mb. On the basis of 113 interactions the total inelastic cross section was found to be 28.1±3.1 mb. The partial cross sections corresponding to inelastic collisions having two, four, six, and eight secondary particles were found to be respectively 16.3±2.4, 11.5±1.8, 0.2±0.1, and 0.1±0.1 mb. While the total inelastic cross section varies slowly with energy, the partial inelastic cross sections were found to be strongly energy dependent. The observed angular distribution of elastically scattered protons in the center-of-mass system was sharply peaked in the forward and backward directions, in fair agreement with calculations based on a simple optical model applicable for energies between 2 and 10 Bev. Particles produced in inelastic collisions were identified as pions or protons by measurements of energy loss and multiple scattering. For those particles identified, center-of-mass system distributions of energy, angle, and transverse momentum are presented.
'ALL'.
We have analyzed 2560 events in the final-state K O 1 K O 1 n produced in π − p interactions at 5, 7 and 12 GeV/ c . We observe the S ∗ (1070), f O and A 2 decaying into K O 1 K O 1 . Resonance parameters, cross sections, and branching ratios are given.
Cross section times branching ratio.
Over 100 unambiguous π − + p → Λ + Λ + n events have been observed in a magnet spark chamber. The data provide good evidence for peripheral production of Λ Λ and n Λ (via meson exchange) and against peripheral n Λ (double baryon exchange). No resonances in the Λ Λ system are observed. Angular distributions and Λ( Λ ) polarizations are analysed.
Axis error includes +- 0.0/0.0 contribution (?////Corrected for neutral decays, absorption).
Differential cross sections for dp elastic scattering from 60° to 175° center of momentum (c.m.) were measured at 3.43, 4.50, 5.75, and 6.60 GeVc incident deuteron momentum. The measurements were made with a two-arm magnetic spectrometer, making use of multiwire proportional chamber detectors. The deuterons were accelerated at the Bevatron of the Lawrence Berkeley Laboratory. Data are compared with predictions of the baryon-pickup model and the one-pion-exchange model. The backward dip at 180° c.m. for 4.5 GeVc, predicted by Craigie and Wilkin using the one-pion-exchange model, is not observed, but reasonable fits to the momentum variation and angular distributions are found. When the data are plotted against the variable Δ of the baryon-pickup model, the s dependence is greatly reduced.
No description provided.
No description provided.
No description provided.
Inclusive energy spectra of protons, deuterons, and tritons were measured with a telescope of silicon and germanium detectors with a detection range for proton energies up to 200 MeV. Fifteen sets of data were taken using projectiles ranging from protons to Ar40 on targets from Al27 to U238 at bombarding energies from 240 MeV/nucleon to 2.1 GeV/nucleon. Particular attention was paid to the absolute normalization of the cross sections. For three previously reported reactions, He fragment cross sections have been corrected and are presented. To facilitate a comparison with theory the sum of nucleonic charges emitted as protons plus composite particles was estimated and is presented as a function of fragment energy per nucleon in the interval from 15 to 200 MeV/nucleon. For low-energy fragments at forward angles the protons account for only 25% of the nucleonic charges. The equal mass Ar40 plus Ca systems were examined in the center of mass. Here at 0.4 GeV/nucleon Ar40 plus Ca the proton spectra appear to be nearly isotropic in the center of mass over the region measured. Comparisons of some data with firestreak, cascade, and fluid dynamics models indicate a failure of the first and a fair agreement with the latter two. In addition, associated fast charged particle multiplicities (where the particles had energies larger than 25 MeV/nucleon) and azimuthal correlations were measured with an 80 counter array of plastic scintillators. It was found that the associated multiplicities were a smooth function of the total kinetic energy of the projectile. NUCLEAR REACTIONS U(Ne20,X), EA=240 MeV/nucleon; U(Ar40,X), Ca(Ar40,X), U(Ne20,X), Au(Ne20,X), Ag(Ne20,X), Al(Ne20,X), U(He4,X), Al(He4,X), EA=390 MeV/nucleon; U(Ar40,X), Ca(Ar40,X), U(Ne20,X), U(He4,X), U(p,X), EA=1.04 GeV/nucleon; U(Ne20,X), EA=2.1 GeV/nucleon; measured σ(E,θ), X=p,d,t.
No description provided.
No description provided.
No description provided.
Data from the MARK-J detector on the reactions e+e−→μ+μ−, τ+τ− in the center-of-mass energy range from 12 to 36.7 GeV are presented. The μ, τ radii are shown to be <10−16 cm. A search has been made for the production of a new heavy lepton and for the production of spin-0 supersymmetric partners of the muon. 95%-confidence-level lower limits of 16 GeV for the mass of a new charged heavy lepton and 15 GeV for the mass of the scalar partners of the muon are obtained.
No description provided.
We have performed a high-statistics measurement of Bhabha scattering and of the production of hadrons in electron-positron annihilation at PETRA energies (12 GeV<~s<~36.7 GeV). Combining the results with measurements of μ+μ− and τ+τ− production enables us to compare our results with electroweak theory. We find sin2θw=0.27±0.08. This is in good agreement with the value obtained from neutrino experiments which were carried out in entirely different kinematic regions.
No description provided.
No description provided.
ASYMMETRY WAS USED.
The measurement of the nonelectromagnetic forward-backward charge asymmetry in the reaction e+e−→μ+μ− at s∼34.6 GeV and in the angular region 0<|cosθ|<0.8 is reported. With a systematic error less than 1%, we observe an asymmetry of (-8.1±2.1)%. This is in agreement with the standard electroweak theory prediction of (-7.6±0.6)%. The weak-current coupling constants are also reported.
SEE PRL 55, 665 FOR DISTRIBUTIONS AT 34.6 GEV AND ABOVE.
SEE PRL 55, 665 FOR CROSS SECTION VALUES AND FORWARD BACKWARD ASYMMETRY.
No description provided.
With a PETRA energy scan in ≤30-MeV steps, the continuum production of open top quark up to 38.54 GeV is excluded. Over regions of energy scan from 29.90 to 38.63 GeV limits are set on the product of hadronic branching ratio and electronic width BhΓee for toponium to be less than 2.0 keV at the 95% confidence level. By a search for flavor-changing neutral currents in b decay, models without a top quark are excluded.
MEASUREMENT OF R IN ENERGY SCAN FROM SQRT(S) = 29.9 TO 3.146 AND 33.0 TO 36.72.
MEASUREMENT OF R IN THE RANGE SQRT(S) 37 TO 38.63 GEV.
THRUST DISTRIBUTION FOR EVENTS IN THE RANGE SQRT(S) 37.94 TO 38.63 AND 38.54 TO 38.63.
With use of the MARK-J detector at s=34.7 GeV 21 000 e+e−→hadron events have been collected. By measurement of the asymmetry in angular energy correlations the strong coupling constant αs=0.13±0.01 (statistical)±0.02 (systematic) is determined, in complete second order, and independent of the fragmentation models and QCD cutoff values used.
DATA REQUESTED FROM THE AUTHORS.
No description provided.
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