Antiproton induced fission probabilities of U238, Bi209, Pb208 and Au177 are reported together with the mass distribution of the fission fragments in the U238 and Bi209 cases. The charged particles multiplicities observed in co-incidence with fission have, also, been measured for U and Bi and are presented.
TOTAL AVERAGE MASSES AND KINETIC ENERGIES OF FISSION FRAGMENTS. Mean mass is in proton mass units.
Distributions of event shape variables obtained from 120600 hadronicZ decays measured with the DELPHI detector are compared to the predictions of QCD based event generators. Values of the strong coupling constant αs are derived as a function of the renormalization scale from a quantitative analysis of eight hadronic distributions. The final result, αs(MZ), is based on second order perturbation theory and uses two hadronization corrections, one computed with a parton shower model and the other with a QCD matrix element model.
Experimental differential Thrust distributions.
Experimental differential Oblateness distributions.
Experimental differential C-parameter distributions.
An estimate of the temperature of protons andπ− mesons in central He−Li, He−C, C−C, C−Ne, C−Cu, C−Pb, O−Pb, Mg−Mg interactions is presented. The results indicate an increase of the proton temperature with increasing mass numbers of projectile and target nuclei (Ap,AT) fromTp=(118±3) MeV for He−Li toTp=(141±2) MeV for C−Pb. The temperature ofπ− mesons does not depend onAP,AT andTπ≃95 MeV. A satisfactory fit forπ− mesons in C−Cu, C−Pb, O−Pb, Mg−Mg collisions can be achieved by using a form involving two temperatures,T1 andT2. The relative yield of the high temperature component (T2) is ≅24% for C−Cu, C−Pb, and Mg−Mg interactions. The observed results forTP in C−Ne, C−Cu and C−Pb collisions are consistent with the prediction of the thermodynamic hagedorn model.
for C-CU and C-PB YRAP=0.3-1.7.
THE D(N)/D(PT) distribution has been fitted by the form: PT*ET*K1(SLOPE*ET), where K1 is Mac-Donaldis function. for C-CU and C-PB YRAP=0.3-1.7.
No description provided.
The process γγ→π+π− was measured using the detector MD-1 at VEPP-4. The two-photon reactionse+e−, μ+ μ− and π+ π− pair production were separated using scintillation counters, Cherenkov counters and shower-range chambers. A radiation widthГγγ(f2(1270))=3.1±0.35±0.35 keV was obtained.
Data read from graph.
Measurements are reported of inclusive production of η-mesons in the beam fragmentation region in γp, πp andKp collisions. Results include a small but significant departure from VMD, and a pronounced rise in theη/π0 ratio with increasingpT.
No description provided.
No description provided.
No description provided.
Enhanced strange particle production, nonstatistical multiplicity fluctuations and two-pion Bose-Einstein correlations were measured in O, S-nucleus reactions at 60 and 200 GeV/nucleon. The results indicate significant collective effects in high-energy nucleus-nucleus collisions.
CENTRAL COLLISIONS.
CENTRAL COLLISIONS.
Product of charged kaons in central S + S and O + Au collisions at 200 GeV/nucleon has been studied in the NA 35 Streamer Chamber experiment. Mean multiplicities and transverse mass distributions were obtained. They were compared with nucleon-nucleon data and with model predictions.
No description provided.
No description provided.
No description provided.
The polarization of the proton from the inclusive breakup reaction 1 H( d , p )X at 2.1 GeV was measured at 0°. The results are expressed as the ratio of the proton polarization, P p , to the deuteron beam polarization, P d , κ 0 = P p / P d . The measured values of κ 0 range from +0.983 to -0.305 and are in general agreement with the expected behavior arising from the D state in the deuteron wave function.
POL(C=DEUT) is the DEUT polarization, the P(P=3,RF=ANTILAB) is the proton momentum in DEUT rest frame.
Average numbers of ϱ 0 , K ∗0 (890) and K ∗0 (890) produced in peripheral collisions (with the number of “grey” protons n g ⩽2) of K + with Al and of π + with Al and Au nuclei at 250 GeV/ c are measured in the EHS(NA22) experiment at the CERN SPS. No evidence is found for suppression of vector meson production relative to K + p and π + collisions at the same energy.
No description provided.
No description provided.
No description provided.
We have measured the cross section for γγ production with the TOPAZ detector in the energy region √ s =50.0–61.4 GeV. The observed cross section for γγ production integrated over |cos θ | ⩽ 0.77 is 50.2±0.8±2.2 pb at 〈√ s 〉=57.6 GeV and the ratio of this value to the QED prediction is 1.01±0.02±0.04. The angular distribution is in good agreement with the QED predictions, thereby setting limits on the compositeness scales, Λ L+R + =168 GeV, Λ L+R − =97 GeV, Λ L,R =141 GeV, Λ L,R − =81 GeV, and Λ L−R ± =68 GeV, at the 95% confidence level. The reaction e + e − → γγγ was also studied and was found consistent with the QED prediction.
No description provided.
No description provided.
No description provided.
Forum