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.
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.
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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.
The inclusive charged-hadron momentum spectra from the ψ and ψ′ decays produced in e+e− collisions at SPEAR are presented. The data were obtained with a small solid-angle, single-arm magnetic spectrometer with good particle-identification abilities centered at 90 degrees with respect to the beams. The particle-separated invariant cross sections are compared with data from e+e− collisions at s=4.8 and 7.3 GeV, obtained with the same spectrometer, in order to observe the difference between hadron production at the resonances and in the continuum.
AT J/PSI.
AT J/PSI.
AT J/PSI.
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AVERAGED DATA FOR 44.9 AND 45.5 GEV.
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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.
Measurements of the reaction γ p → p π + π − π + π − are presented, in which π + π − π + π − systems with masses up to 3 GeV are produced from fragmentation of the incident photon. The reaction is dominated by production of the large peak of the ϱ′(1600) meson and, at higher masses ≳2 GeV, y production of jet-like 4 π systems. The ϱ′(1600) meson is produced by a predominantly s -channel helicity conserving mechanism. At higher masses there are also indications of ϱπ peaks, of masses 1.3 GeV (the A 2 meson) and 1.75 GeV, produced with a recoiling π meson by a mechanism consistent with the Deck effect.
CORRECTED FOR TAILS OF BREIT-WIGNER RESONANCE USED IN FIT AND ALLOWING FOR 10 PCT BACKGROUND.
Charged hadron production ine+e− annihilation is studied in the 7 to 10 GeV CM energy region and at the Υ (9.46) and Υ′ (10.01) resonances with the LENA detector at DORIS. The statistical moments of the charged multiplicities are studied. The data show KNO scaling behaviour and suggest the presence of long range correlations. An average charged multiplicityrise of Δn(Υ)=0.55±0.19 and Δn(Υ′)=1.26±0.29 over the continuum is observed for the Υ and Υ′ direct decays. The jet structure of the Υ and Υ′ direct decays is investigated using the charged particles. The polar angular distributions of the jet axis behave like 1+α(T) cos2θ with 〈α(T)〉Υ=0.7±0.3 and 〈α(T)〉Υ′=0.6±0.4. The 〈α(T)〉Υ value is in agreement with the QCD vector gluon assignment and excludes scalar gluons by more than four standard deviations.
No description provided.
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The inclusive reactions h+p→ φ +X, (h= π ±, ,K ± ,p ± ), are studied for 0⪅ x F ⪅0.3 and p ⊥ ⩽ 1 GeV at 93 and and 63 GeV incident momentum. Differential cross sections d σ /d p ⊥ 2 and dσ /d x F are presented and are compared with predictions of the naive parton model.
No description provided.
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Performing a PWA of the π − π − π + system over the −t p/p range 0.2 to 0.4 GeV 2 we find evidence for a J P = 0 − , J G =1 − meson of mass 1342 ± 20 MeV and width 220 ±70 MeV decaying into ϵπ. This state is produced by natural parity exchange with a slope similar to that of elastic scattering. It can be interpreted as a radial excitation of the π meson (π′).
INTEGRATING EXTRAPOLATED EXPONENTIAL FIT GIVES A TOTAL CROSS SECTION OF ABOUT 54 MUB.
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