We present evidence for the exclusive reaction e+e−→Ds±Ds*∓, observed with the Mark III detector at the SLAC storage ring SPEAR. The Ds± is reconstructed in the φπ± decay mode, while the Ds*∓ is detected as a narrow peak in the recoil-mass distribution. The mass of the Ds* is found to be 2109.3±2.1±3.1 MeV/c2, yielding a Ds*−Ds mass difference of 137.9±2.1±4.3 MeV/c2. The width of the Ds* is <22 MeV/c2 at the 90%-confidence level. The observed signal corresponds to σ(e+e−→Ds+Ds*−+Ds−Ds*+)B(Ds+→φπ+)=30±6±11 pb at s=4.14 GeV.
No description provided.
In a study of proton-proton interactions at\(\sqrt s= 26GeV\), inclusive distributions of single pions and systems of pions of various charge combinations are presented, as well as the production ratio obtained in association with various trigger particles. The results are compared to current phenomenological models in an attempt to understand multiparticle productions in hadron collisions.
.
None
No description provided.
No description provided.
No description provided.
We present inclusive ¶ and K *0 (892) cross sections and Feynman x -spectra in K + p collisions at 250 GeV/ c . In the K + fragmentation region, x > 0.2, the ratio of ¶ to K *0 (892) is used to estimate the strangeness suppression factor λ , with the result γ =0.17 ± 0.02 (stat ± 0.01 (syst). We see no evidence for an energy dependence of λ in the CM energy range 7.8 ≤ s ≤21.7 GeV.
RESULTS AT 32 AND 70 GEV INCLUDED FOR COMPARISON.
RESULTS AT 32 AND 70 GEV INCLUDED FOR COMPARISON.
RESULTS AT 32 AND 70 GEV INCLUDED FOR COMPARISON.
Inclusive data are presented on ϱ 0 ,ϱ + and ω produced in k + p interactions at 250 GeV/ c , for ϱ + and ω for the first time in K + p experiment. In the forward CM hemisphere, the ϱ + , ϱ 0 and ω differential production rates are equal within errors, and remarkably similar to muon-inelastic scattering data on ϱ 0 and ω at 280 GeV/ c .
No description provided.
We have measured the production of prompt positrons in pp collisions at √ s = 63 GeV and y = 0 in the p T interval 0.12< p T <1.0 GeV/c. The results indicate that the production of positrons at low p T (<0.4 GeV/ c ) is proportional to the square of the mean multiplicity in the central region | y | < 1. Such a quadratic dependence is not expected from final-state sources such as hadronic bremsstrahlung or hadronic decays, but is natural in models where low mass electron pairs are produced by interactions of constituents created during the collision.
No description provided.
No description provided.
No description provided.
Results are presented from reactions of 60 A GeV and 200 A GeV 16 O projectiles with C, Cu, Ag, and Au nuclei. Energy spectra measured at zero degrees and transverse energy distributions in the pseudorapidity range from 2.4 to 5.5 are shown. The average transverse energy per participant is found to be nearly independent of target mass. Estimates of nuclear stopping and of attained energy densities are made.
STOPPING POWER IS THE QUANTITY GIVEN IN THIS TABLE. IT IS DEFINED AS ( D(ET(EXP)/D(ETA) / D(ET(THEORY)/D(ETA) ) AND THE DENOMINATOR IS TAKEN TO BE 0.5*E(HADRON IN CM). ETA IS THE PSEUDO-RAPIDITY.
Neutrino and antineutrino total charged current cross sections on iron were measured in the 100, 160, and 200 GeV narrow band beams at the CERN SPS in the energy range 10 to 200 GeV. Assuming σ/E to be constant, the values corrected for non-isoscalarity are σv/E = (0.686 ± 0.019) * 10−38 cm2/ (GeV · nucleon) and σv/E = (0.339 ± 0.010) * 10−38 cm2/ (GeV·nucleon). Between 50 and 150 GeV no energy dependence of σ/E was observed within ±3% for neutrino and ±4% for antineutrino interactions.
Measured charged current total cross section.
Measured charged current total cross section.
No description provided.
The process γγ→π+π−π+π− has been investigated in reactions of the typee+e−→e+e−π+π−π+π− in the single tag mode. The range of the four momentum squared of one of the virtual photons was 0.28 GeV2/c2≦Q2≦3.6 GeV2/c2, the average being 〈Q2〉=0.92 GeV2/c2; the other photon was quasi real. The reaction is mainly described by the channels γγ→ρ0ρ0 and γγ→4π (phase space), occuring with about equal probability. TheQ2-dependence of the cross section is in agreement with the ρ form factor.
Data read from graph.. Additional overall systematic error 25%.
Data read from graph.. Additional overall systematic error 25%.. The Q**2 approx 0 datum is deduced from the earlier TASSO paper, Brandelik et al, Phys. Lett. 97B(1980)448, (<a href=http://durpdg.dur.ac.uk/scripts/reacsearch.csh/TESTREAC/red+1151> RED = 1151 </a>) on rho0 rho0 production.
None
No description provided.