The production of charged kaon pairs in two-photon interactions has been studied with the ARGUS detector and the topological cross section has been measured. The γγ-widths and interference parameters have been determined for the tensor mesonsf2 (1270),a2 (1318) andf′2 (1525). The helicity structure assumed for the continuum contribution has a significant effect on the result. Upper limits have been obtained for the γγ-widths of the glueball candidate statesf2 (1720) andX (2230).
Data read from graph.. Errors are the square roots of the number of events.
Cross section allowing for spin components JM = 22,20,00. Data read from graph.. Additional overall systematic error 8.4%.
Cross section allowing for spin components JM = 22,00. Data read from graph.. Additional overall systematic error 8.4%.
We have measured inclusive distributions for charged particles in hadronic decays of the Z boson. The variables chosen for study were charged-particle multiplicity, scaled momentum, and momenta transverse to the sphericity axes. The distributions have been corrected for detector effects and are compared with data from e+e− annihilation at lower energies and with the predictions of several QCD-based models. The data are in reasonable agreement with expectations.
Mean corrected charged particle multiplicity.
Corrected charged particle X distributions. Errors are statistical and systematic combined.
Corrected charged particle PTIN distributions. Errors are statistical and systematic combined.
We present measurements of the pseudorapidity (η) distribution of charged particles (dNchdη) produced within |η|≤3.5 in proton-antiproton collisions at s of 630 and 1800 GeV. We measure dNchdη at η=0 to be 3.18±0.06(stat)±0.10(syst) at 630 GeV, and 3.95±0.03 (stat)±0.13(syst) at 1800 GeV. Many systematic errors in the ratio of dNchdη at the two energies cancel, and we measure 1.26±0.01±0.04 for the ratio of dNchdη at 1800 GeV to that at 630 GeV within |η|≤3. Comparing to lower-energy data, we observe an increase faster than ln(s) in dNchdη at η=0.
General rapidity densities.
No description provided.
Differential pseudorapidity distribution.. The numbers here at 1800 GeV have been taken from the HZTool routine hzf89201e provded by Arthur Moraes.
Using data onvp and\(\bar vp\) charged current interactions from a bubble chamber experiment with BEBC at CERN, the average multiplicities of charged hadrons and pions are determined as functions ofW2 andQ2. The analysis is based on ∼20000 events with incidentv and ∼10000 events with incident\(\bar v\). In addition to the known dependence of the average multiplicity onW2 a weak dependence onQ2 for fixed intervals ofW is observed. ForW>2 GeV andQ2>0.1 GeV2 the average multiplicity of charged hadrons is well described by〈n〉=a1+a2ln(W2/GeV2)+a3ln(Q2/GeV2) witha1=0.465±0.053,a2=1.211±0.021,a3=0.103±0.014 for thevp anda1=−0.372±0.073,a2=1.245±0.028,a3=0.093±0.015 for the\(\bar vp\) reaction.
No description provided.
No description provided.
No description provided.
Energy spectra of protons, deuterons and tritons from the annihilation of antiprotons stopped in 12 C, 40 Ca, 63 Cu, 92,98 Mo and 238 U have been measured with a Ge-detector telescope. Parameters related to the shape of the spectra were calculated and their dependence on target and ejectile mass number was determined. Yields per p̄ of directly emitted protons, deuterons and tritons and of evaporated protons were estimated.
THE PROTON SPECTRA WERE FITTED WITH THE EXPRESSION N(E)=N1*EXP( -SLOPE(Q=1)*E)+N2*EXP(-SLOPE(Q=2)*E).
Axis error includes +- 0.0/0.0 contribution (?////).
Axis error includes +- 0.0/0.0 contribution (?////).
The pion induced pion production (π, 2π) reaction on deuterium has been studied at an incident pion energy of 280 MeV. The outgoing pions were detected in coincidence and the measured four-fold cross sections were compared with a πN → ππ N microscopic model, and, upon integration, with the available experimental total cross sections from the same reaction on H and 2 H. Finally, the results were directly compared with recent data from the 16 O(π + , π + π − ) reaction at the same incident energy.
No description provided.
The mean multiplicity and the angular distribution of the charged pions produced in the n̄ annihilation on Fe in the range from 12 to 140 MeV is presented. The experimental technique and methods of analysis are described. A comparison with the p̄ results is performed, together with a discussion of some possible pion-nucleus interaction mechanisms in the above n̄ energy range.
No description provided.
This work represents the results of an experimental investigation of the electromagnetic dissociation of 200 GeV/nucleon 16 O and 32 S ions in nuclear emulsions. Exclusive channels involving charged fragments have been studied as a function of the energy released, and, assuming a Weizsäcker-Williams spectrum of virtual photons, there is a good agreement with results for the (γ, p) processes obtained with real photons. However, the rates found for other processes are larger, in particular for the (γ, α) on both nuclei. The values of the total integrated absorption cross sections are generally larger than those obtained from real photon experiments but the extent of the discrepancy depends strongly upon which photon results are used in the comparison.
ELECTROMAGNETIC DISSOCIATION IN NUCLEAR EMULSION.
ELECTROMAGNETIC DISSOCIATION IN NUCLEAR EMULSION.
NUCLEUS IS THE EMULSION.
None
Data from Run 1. There is an additional overall systematic uncertainty of 5.2 pct.
Data from Run 2. There is an additional overall systematic uncertainty of 5.2 pct.
Average R value.
The study of the J ψ transverse momentum distribution in oxygen-uranium reactions at 200 GeV/nucleon shows that 〈 P T 〉 and 〈 P T 2 〉 increase with the transverse energy of the reaction. Muon pairs in the mass continuum do not exhibit the same behaviour. The comparison of the J ψ production rates in central and peripheral collisions shows a significant diminution for low P T central events.
Two parametrization of the D(SIG)/D(PT) are used: first is : PT*exp(-SLOPE*PT**CONST(C=PT)) and second is : PT*exp(-2*MT/CONST(C=MT)).
D(SIG)/D(PT) is parameterized as PT*exp(-SLOPE*PT**CONST).
D(SIG)/D(PT) is parameterized as PT*exp(-SLOPE*PT**CONST).
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