The charged particle multiplicities of the quark and gluon jets in the three-fold symmetric e + e − → q q g events at √ s = 29 GeV have been studied using the high resolution spectrometer at PEP. A value of 〈 n 〉 g = 6.7 −2.1 +1.1 ±1.0 for gluon jet s with an energy of 9.7 −2.0 +1.5 GeV is measured. The ratio, 〈 n 〉 g /〈 n 〉 q , is 1.29 −0.41 +0.21 ±0.20, which i s significantly lower than the value of 9 4 naively expected from the ration of the gluon-to-quark color charges.
Mean jet charged particle interpretations for gluon and quark jets as described above.
The relative yields of kaons and protons compared with the yield of pions at highpT and polar angles θ away from 90° (in the range from 10° to 45°) are presented forpp, dd, and αα interactions at a centre-of-mass energy\(\sqrt {s_{NN} }= 31\) GeV per nucleon-nucleon collision. The measured particle ratios depend on the atomic mass numberA of the beam particles and on θ. TheA dependence of the ratios becomes stronger for largerpT and is more pronounced at smaller polar angles.
ERRORS ARE PURELY STATISTICAL.
ERRORS ARE PURELY STATISTICAL.
ERRORS ARE PURELY STATISTICAL.
Measurements are presented of the variation with Q 2 (scaling violation) of the hadron multiplicity in deep inelastic muon-proton scattering. An increase in the average multiplicity of both the charged hadrons and K 0 mesons is observed with increasing Q 2 or x Bj for fixed centre-of-mass energy W . The study of the shape of the effective fragmentation function D h ( z , W , Q 2 ) shows that the increase of the particle yield with Q 2 takes place for low z particles. The variation of the hadron distributions with Q 2 is also studied in the current fragmentation region where a decrease in multiplicity is observed. Such effects are expected from QCD.
No description provided.
No description provided.
Inclusive production of charged particles has been studied in e + e − annihilation at s s=29 GeV using the high resolution spectrometer at PEP. Differential cross sections are presented in the range of scaled energy 0.1< z <1.0. The data for z <0.5 show the (1− z ) 2 behavior predicted by the dimensional counting rules. Comparisons are made with predictions of the Lund string model and the Webber cluster model.
Data requested from authors.
The cross section for the production of π+π− or K+K− pairs in γγ interactions is measured for mππ between 1.7 and 3.5 GeV/c2 and for two intervals of γγ center-of-mass scattering angle. Results are compared with predictions of a QCD model.
Data read off graph.
Data read off graph.
Evidence is presented for a narrow state, called ξ, in the decay modes J/ψ→γξ, ξ→K+K−, and ξ→KS0KS0. In the K+K− mode, the ξ has a mass of 2.230±0.006±0.014 GeV/c2, a width of Γ=0.026−0.016+0.020± 0.017 GeV/c2, a product branching ratio of (4.2−1.4+1.7±0.8)×10 −5, and a statistical significance of ∼4.5 standard deviations. In the KS0KS0 mode, it has a mass of 2.232±0.007±0.007 GeV/c2, a width of Γ=0.018−0.015+0.023± 0.010 GeV/c2, a product branching ratio of (3.1−1.3+1.6±0.7)×10 −5, and a statistical significance of ∼3.6 standard deviations. Limits on ξ decay to other final states are presented.
No description provided.
New data is presented on the ratios of structure functions F 2 ( x , Q 2 ) measured in deep inelastic muon scattering with deuterium, nitrogen, and iron targets. The existence of nuclear effects at large Q 2 is confirmed with improved systematic accuracy. The ratio F 2 Fe ( x ) F 2 D 2 ( x ) covers the range 0.20 ⩽ x ⩽ 0.70 and is in agreement with earlier measurements. The ratio F 2 N 2 ( x )/ F 2 D 2 ( x ) is measured over the range 0.08 ⩽ x ⩽ 0.70 and is compatible with unity below x = 0.3.
VALUES OF Q2 CORRESPONDING TO THE X-BINS IN THIS TABLE ARE:- 46-106,46-106,53-150,53-200,70-200,80-200 RESPECTIVELY.
VALUES OF Q2 CORRESPONDING TO THE X-BINS IN THIS TABLE ARE:- 26-40,26-61,30-80,30-106,30-106,30-150,30-200,35-200,46-200.
Separate samples of charm quark and light quark (u, d, s) jets have been isolated in an experiment studying e + e − annihilations at s = 29 GeV . The results come from data corresponding to an integrated luminosity of 111 pb −1 collected by the High Resolution Spectrometer. Differences were observed in charged multiplicities, momentum distributions, and rapidity of the size expected from the different fragmentation functions and leading particle decay properties of the two samples.
Charm Quark Jet Trigger. Characteristics of Jet Opposite the Trigger Jet.
Light Quark Jet Trigger. Characteristics of Jet Opposite the Trigger Jet.
No description provided.
We report a measurement of the inclusive charged-particle distribution for gluon jets derived from nearly threefold-symmetric three-jet events taken at center-of-mass energy of 29 GeV in e+e− annihilation. The charged-particle spectrum for these jets is observed to fall off more rapidly than those of quark jets of the same energy.
Errors include both statistics and the uncertainty in correction factors. X is defined at the energy of the individual particle divided by the total energy of the jet to which it is assigned.
The reaction γγ→π0η has been investigated with the Crystal Ball detector at the DESY storage ring DORIS II. Formation of δ(980) and A2(1320) has been observed with γγ partial widths Γγγ(A2)=1.14±0.20±0.2 6 keV and Γγγ(δ)B(δ→πη)=0.19±0.07 −0.07+0.10 keV.
No description provided.
No description provided.
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