We have measured the inclusive cross section for η production in e+e− interactions near charm threshold using the Crystal Ball detector. No pronounced structure in the energy dependence is observed. By comparing cross sections above and below charm threshold we obtain the limits (90% confidence limit): R(e+e−→FF¯X)RB(F→ηx)<0.15−0.32 (for Ec.m. from 4.0 to 4.5 GeV), RB(D→ηx)<0.13. Our results are inconsistent with a previous report of a large energy dependence of the η cross section ascribed to the crossing of the FF* and F*F* production thresholds.
Axis error includes +- 0.0/0.0 contribution (?////DECAY PI0 --> 2GAMMA//RES-DEF(RES=ETA,BACK=CORRECTED,DEF=340 < M( 2GAMMA ) < 800 MEV)//DECAY-BR(BRN=ETA --> 2GAMMA,BR=38 PCT)).
THE 4.028 GEV DATA ARE NOT INCLUDED IN THE 4.005-4.082 GEV BIN. Axis error includes +- 0.0/0.0 contribution (?////DECAY PI0 --> 2GAMMA//RES-DEF(RES=ETA,BACK=CORRECTED,DEF=340 < M( 2GAMMA ) < 800 MEV)//DECAY-BR(BRN=ETA --> 2GAMMA,BR=38 PCT)).
AT FIXED ENERGIES.
Data from an exposure of BEBC filled with hydrogen to a wideband neutrino beam are analysed to yield the structure function F v p 2 ( x ) for x > 0.2. Using our results in combination with data from electron-proton and muon-proton scattering, the quark density ratio d/u is determined as a function of x . The dominance u at large x is clearly seen. The results are compared with theoretical predictions.
No description provided.
No description provided.
No description provided.
The reaction γ p → K + K − p has been investigated with tagged photons in the energy range of 20 < E γ < 70 GeV. A structure in the 1.7 GeV mass region is observed and interpreted in terms of a recurrence of the ø.
No description provided.
The reaction π − p → φφ n has been isolated at 16 GeV/ c and its cross section determined to be 40 ± 10 nb. The φφ mass spectrum shows a threshold enhancement between 2.1 and 2.5 GeV. A successful description of the angular content of the φφ system requires two interferingss J P = 2 + states.
No description provided.
SLOPE OF DIFFERENTIAL TP(P=3,P=2) DISTRIBUTION.
Results on inclusive K s 0 production in e + e − annihilation at mean center-of-mass energies of 9.4, 12.0 and 30 GeV are presented. The ratio R (K 0 ) = 2 σ (K s 0 )/ σ μμ rises from 3.10 ± 0.75 at √ s = 9.4 GeV to 5.6 ± 1.2 at √ s = 30 GeV, corresponding to an approximately constant K 0 /charged-particle ratio of 0.12 ± 0.02. A similar ratio for K 0 / charged particle is observed for direct hadronic decays of the ϒ.
SYSTEMATIC ERROR INCLUDED.
NUMBER OF K0 PER HADRONIC EVENT. AUTHORS ALSO USE MULTIPLICITY TO ESTIMATE NUMBER OF K0 PER CHARGED PARTICLE.
INCLUDING EARLIER DATA.
Charged-current neutrino interactions have been analysed in a sample of pictures from BEBC equipped with a TST. Using a method independent of both the neutrino flux and nuclear interaction corrections, the ratio R = σ n / σ p has been measured. The result is R =1.98±0.19 for the ratio of total cross sections. Bjorken x distributions for proton and neutron targets and for u and d quarks are compared.
No description provided.
No description provided.
No description provided.
Data on hadron production by e + e − annihilation at c.m. energies between 12 and 36.6 GeV have been collected using the JADE detector. They have been analysed in terms of single-photon and weak neutral-current exchange assuming production of quark-antiquark pairs with only d, u, s, c and b quarks to produce values for the quark weak neutral-current couplings. A further analysis in terms of the Glashow-Salam-Weinberg theory produced the result, sin 2 θ W = 0.22 ± 0.08 . The theory has therefore been tested in a new energy domain and within the context of the neutral weak couplings of the first, second and third generation quarks.
No description provided.
WIDTH(Z) = 2.5 GEV WAS ASSUMED. CONST(N=SIN2TW) WAS DETERMINED FROM RATIO(HADRONS/MU). FIRST ORDER QCD.
The p p elastic differential cross section at 50 GeV/c has been measured in a two-arm spectrometer experiment at the CERN SPS. The | t | range covered extends from 0.7 to 5 (GeV/c. A pronounced dip-bump structure is observed with a sharp minimum at | t | = 1.5 (GeV/ c ) 2 .
No description provided.
Inclusive production of ϱ0,K*±(892), andf is studied in\(\bar p\)p interactions at 12 GeV/c. The inclusive cross sections for ϱ0,K*±(892), andf are found to be 6.7±0.3 mb, 1.0±0.2 mb, and 1.4±0.3 mb, respectively. The differential cross sections are presented as a function of c.m. rapidity, Feynmanx and square of the transverse momentumpT2. Comparison with the correspondingpp data shows some interesting differences which can be attributed to the\(\bar p\)p annihilation. The results are compared with the predictions of the quark fusion model.
No description provided.
No description provided.
No description provided.
The final states of charged hadrons produced in 280 GeV μp scattering are analysed with respect to their planarity and jet structure. Distributions of p ⊥ 2 in and p ⊥ out 2 are presented. A two jet structure in the forward hemisphere is observed for events with high p ⊥ tracks are predicted by QCD models.
PTIN**2 is the sum of the PTIN components squared.
PTOUT**2 is the sum of the PTOUT components squared.
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