The energy dependence of the transverse momentum invariant distribution of pions and neutral kaons is studied in K − p interactions between 14.3 and 70 GeV/ c . The large P T part of the distributions violates the Feynman scaling and, above P T ≃ 1.5 GeV/ c , appears to be reasonably described by hard scattering models. The variation of the average transverse momentum is also studied as a function of the c.m. reduced longitudinal momentum, and its behaviour is compared to the data obtained via the hadronic shower produced in lepton-hadron interactions.
HERE K0 MEANS K0 OR AK0 I.E. K(NEUTRAL).
No description provided.
The differential cross sections for Bhabha scattering and μ pair production, and the total τ pair cross section as measured by the PLUTO detector at PETRA, have been analyzed to extract information on the weak interaction of leptons. The data are compared with unified gauge theories. Since the observed electroweak effects are still consistent with zero (within errors) we can set experimental limits on neutral current parameters atQ2 values of 950 GeV2. In the framework of the standard SU(2)×U(1) model we find sin2Θw<0.52(95% c.l.). In the context of general singleZo models we can excludeZo masses of less than 40 GeV.
No description provided.
No description provided.
A multi-jet analysis of hadronic final states from e + e − annihilation in the energy range 27 < E cm < 32GeV is presented. The analysis uses a cluster method to identify the jets in a hadronic event. The distribution of the number of jets per event is compared with several models. From the number of identified coplanar three-jet events the strong coupling constant is determined to beα S = 0.15 ± 0.03 (stat. error) ± 0.02 (syst. error). The inferred energy distribution of the most energetic parton is in good agreement with the first-order QCD prediction. A scalar-gluon model is strongly disfavoured. Higher-twist contributions to the three-jet sample are found to be small.
No description provided.
We present new high statistics data on hadron production in photon-photon reactions. The data are analyzed in terms of an electron-photon scattering formalism. The dependence of the total cross section of Q 2 , the four-momentum transfer squared of the scattered electron, and on the mass W of the hadronic system is investigated. The data are compared to predictions from Vector-Meson Dominance and the quark model.
No description provided.
DEPENDENCE ON VISIBLE HADRONIC INVARIANT MASS.
Data read from graph.
Evidence is presented for inclusive photoproduction of F ± mesons in three decay modes, ηπ ± , ηπ ± π + π − and ηπ ± π + π + π − π − . The average mass of the F ± is found to be 2.020±0.010 GeV.
No description provided.
We report on the results of a partial-wave analysis of the 3π system produced by baryon exchange in the reaction K − p→ Σ − π + π + π − at 4.2 GeV/ c . We confirm the existence of an enhancement in the 1 + S( ϱπ ) wave as previously established from a Dalitz plot analysis of the same data. The phase variation of this wave is found to be consistent with that expected for a resonance and thus the enhancement is identified with A 1 production. No clear signal for this state is found in either the reaction K − p→ Σ + π + π + π − π − or K − p→ Λπ + π − π 0 . We also find production via baryon exchange of the A 2 in all three reactions and the ω and ω ∗ (1975) in the third reaction.
SIMPLE BREIT-WIGNER RESONANCE FITS. CORRECTED FOR UNOBSERVED DECAY MODES.
No description provided.
Measurements have been made of the polarised target asymmetry parameter T for eta photoproduction from protons at a photon energy of 4 GeV and t -values of −0.4, −0.6 and −0.8 (GeV/ c ) 2 . The results are compared with predictions for this quantity.
No description provided.
The resonance parameters of the ϒ′(10.01) were measured using the LENA detector at the DORIS e + e − storage ring. We obtained a mass of M ( ϒ ′) = (10 013.6 ± 1.2 ± 10.0) MeV and an electronic width of Γ ee ( ϒ ′) = (0.53 ± 0.07 −0.05 +0.09 keV. The upper limit set to the μ-pair branching ratio is 3.8% which implies a lower limit on the total ϒ′ width of 14 keV. Together with out previous measurement of the ϒ parameters we obtain a mass difference M(ϒ′) − M(ϒ) = (552.0 ± 1.3 ± 10.0) MeV and Γ ee (ϒ′) Γ ee (ϒ) = 0.43 ± 0.07 −0.00 +0.05 .
HADRONIC CROSS SECTION IN REGION OF UPSI(10020)0.
Proton-proton elastic scattering using 201- and 400-GeV/c extracted beams at Fermilab has been measured in the region 4.9<−t<14.4 GeV2. Contrary to predictions of diffraction models, there is no sign of a second dip or "break," and the slope A in the fit exp(At) is smaller than predicted. It drops from 1.5 to 0.8 GeV−2 over our t range. The shape of the t distribution can be fitted by the power law dσdt∝t−8.4 which is close to a quantum-chromodynamics (QCD) prediction of t−8. At fixed t the 201-GeV/c cross sections are about 2.3 times those at 400 GeV/c which is compatible with the QCD and constituent-interchange-model prediction that dσdt∝s−10 at fixed ts.
LOW T.
HIGH T.
LOW T.
The cross sections of several exclusive reactions in p p interactions are given. In the channels p p → p p π + π − and p p → p p 2π + 2π − which dominate the interactions, the single and double diffractive dissociations are analysed and compared to the results obtained with K ± p interactions at the same energy, pp and p p interactions at other energies. The test of factorization at the p → p π + π − vertex is well verified. The process p p → Δ ++ Δ ++ is studied and the cross sections of Δ ++ , Δ ++ , ϱ 0 and f 0 production are also given.
No description provided.
No description provided.
No description provided.
Forum