The inclusive production of π ± mesons in e + e − annihilation has been measured at c.m. energies of 14, 22 and 34 GeV for pion momenta between 0.3 ans 10 GeV/ c . The fraction of pions among the charged hadrons is above 90% at 0.4 GeV/ c and decreases to about 50% at high momenta. The scaled cross sections ( s β ) d σ d x at 14, 22 and 34 GeV as well as the 5.2 GeV data from DASP have a rather similar x dependence. After integration over the x range from 0.2 to 0.6 the cross sections indicate a monotonic decrease with increasing centre-of-mass energy.
PION FRACTIONS IDENTIFIED BY INNER TOF COUNTERS (ITOF). ERRORS SHOWN ARE STATISTICAL ONLY.
PION FRACTIONS IDENTIFIED BY INNER TOF COUNTERS (ITOF). ERRORS SHOWN ARE STATISTICAL ONLY.
PION FRACTIONS IDENTIFIED BY INNER TOF COUNTERS (ITOF). ERRORS SHOWN ARE STATISTICAL ONLY.
The reactions π − p → p π − and π − p → p ϱ − ( ϱ − → π − π 0 ) at 10 GeV/ c with the proton in the forward direction in the c.m.s. are discussed on the basis of 953 elastic scattering events and 2240 events of the reaction π − p → p π − π 0 . The total backward cross sections are 0.52±0.10 and 1.52±0.28 μ b, respectively. In both cases the production mechanism is compatible with the dominance of the baryonic Δ δ Regge trajectory exchange. The ϱ − decay angular distributions are studied in the u -channel helicity frame and the spin density matrix elements are presented as functions of u .
No description provided.
DATA FROM PRIV COMM WITH B. GHIDINI.
DATA FROM PRIV COMM WITH B. GHIDINI.
Results from K± elastic and inelastic scattering from C12 and Ca40 are reported. The data were all taken at an incident momentum of 800 MeV/c over an angular range from 2° to 38°. The elastic data are compared to first-order optical model calculations in coordinate and momentum space; good qualitative agreement is obtained. The inelastic data (from C12 only) are compared to distorted-wave Born approximation calculations, and good agreement is found if "realistic" inelastic transition densities are used. Although a first-order optical potential description does not describe the data fully, there are strong indications of the increased penetrability of K+ over K− in this energy range. NUCLEAR REACTIONS C12(K±,K±)C12, Ca40(K±,K±)Ca40, E=442 MeV (800 MeV/c), measured σ(θ) for elastic and inelastic scattering, compared to optical model and DWBA calculations, deduced optical potential parameters; θ=2°−38°, Δθ=1°.
X ERROR D(THETA) = 1.0100 DEG.
X ERROR D(THETA) = 1.0100 DEG.
X ERROR D(THETA) = 1.1000 DEG.
Data on inclusive kaon production in e+e− annihilations at energies in the vicinity of the ϒ(4S) resonance are presented. A clear excess of kaons is observed on the ϒ(4S) compared to the continuum. Under the assumption that the ϒ(4S) decays into BB¯, a total of 3.38±0.34±0.68 kaons per ϒ(4S) decay is found. In the context of the standard B-decay model this leads to a value for (b→c)(b→all) of 1.09±0.33±0.13.
No description provided.
ACCEPTANCE CORRECTED MOMENTUM DISTRIBUTIONS FOR CONTINUUM AND UPSILON EVENTS WITH THE CONTINUUM SUBTRACTED.
We have measured, at an average centre-of-mass energy of 34.22 GeV a forward-backward charge asymmetry in the reaction e + e − → μ + μ − of value −0.161 ± 0.032. This demonstrates the existence of an axial vector neutral current with coupling strength of g e a g μ a =0.53 ± 0.10. We have also obtained a limit on the vector coupling strength of g e v g μ v <0.12. The Weinberg angle is found to be sin 2 θ W =0.29 +0.09 −0.11 . From the reaction e + e − → τ + τ − we have found g e a g τ a <0.34, g e v g τ v <0.55.
No description provided.
No description provided.
No description provided.
None
No description provided.
No description provided.
No description provided.
We report on inclusive K 0 production in the region of the upsilon resonances (9.4–10.6 GeV). The K 0 yield for the resonances and continuum below the B B threshold is found to be constant at 0.82 ± 0.10 K 0 per observed hadronic event. At the ϒ (4S), however, the K 0 yield is significantly higher, 1.58 ± 0.35. This increase in K 0 production and the differential cross section d σ /d p of kaons are consistent with B B decay of the ϒ (4S) resonance with the bottom quarks subsequently decaying primarily into charmed quarks.
No description provided.
ACCEPTANCE CORRECTED INCLUSIVE K0 MOMENTUM DISTRIBUTION AT THE UPSI(10570)0.
The reaction π − p→ π 0 π 0 n has been measured with a 648 channel hodoscope spectrometer for the detection of the four γ's from the π 0 decays. The π 0 π 0 D-wave is fully compatible with the f 0 contribution as it is determined in high-statistics π + π − experiments. The magnitude of the π 0 π 0 S-wave and the cosinus of its phase angle (relative to the known D-wave) are determined from fits to the π 0 π 0 angular distributions. Argand diagrams for the I = 0 amplitude S 0 are given for the range 1000 to 1500 MeV/ c 2 . Two solutions exist. One exceeds the unitarity limit above 1200 MeV/ c 2 . The other remains within the unitarity limit and is nearly elastic up to 1450 MeV/ c 2 . It indicates an S 0 wave resonance around 1300 MeV/ c 2 .
No description provided.
No description provided.
The CUSB detector at the Cornell Electron Storage Ring has been used to measure R=σ(e+e−→hadrons)σ(e+e−→μ+μ−) in the c.m. energy regions between the ϒ′′ and the ϒ′′′, and above the ϒ′′′ up to s=11.6 GeV, with integrated luminosities of 5000 and 2100 nb−1, respectively. No narrow resonances are observed, and limits on the leptonic widths are presented. The average value of R increases by 0.31±0.06 across the flavor threshold.
UNCORRECTED VALUES OF R.
UNCORRECTED R VALUES BELOW AND ABOVE UPSI(10.5).
FULLY CORRECTED R VALUES, ASSUMING B AB PRODUCTION IS TOTALLY RESPONSIBLE FOR THE EXCESS ABOVE UPSI(10.5).
The spin-spin correlation parameter CLL=(L, L; 0, 0) has been measured for p−p elastic scattering around θc.m.=90° up to plab=5 GeV/c. An interesting energy dependence is observed in CLL and the results are interpreted by comparison with other available data.
NUMERICAL VALUES OF DATA IN FIGURE SUPPLIED BY A. YOKOSAWA.