Evidence is presented for a newK*\(\bar K\)+c.c. resonance with a mass of (1,526±6) MeV, a width of (107±15) MeV and quantum numbersIJPC=01++. We call itD′ meson. Initially it is observed as aK*\(\bar K\)+c.c. enhancement in the reactionsK−p→(Ks0K±π∓)Λ at 4.2 GeV/c. The isospin assignmentI=0 comes from its further observation in the reactionsK−p→(Ks0K±π∓)Σ0 andK−p→(Ks0K±π∓)Σ(1,385)0 but not inK−p→(K+K−π−)Σ+ orK−p→(Ks0K±π∓)Σ(1,385)+. A maximum likelihood analysis of the (K\(\bar K\)π) decay Dalitz plots in the reactionsK−p→(Ks0K±π∓) determines theJPC of theD′ meson to be 1++. A satisfactorySU(3) fit is obtained to a 1++ nonet composed of theI-1A1, theI=1/2QA with theD(1,285) and theD′(1,526) as theI=0 members having a mixing angle close to the magic one.
CROSS SECTIONS FOR PRODUCTION IN FORWARD DIRECTION IN THE REACTION CM FRAME WITH RESPECT TO K- BEAM. CORRECTION FOR UNOBSERVED (K AK PI) DECAY MODES AND FOR INVISIBLE LAMBDA AND K0 DECAYS.
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Results from a partial wave analysis of theKππ system produced in the hypercharge exchange reaction π−p→(K+π−π0)Λ at 3.95 GeV/c are presented. SignificantQ1 production is observed but no evidence is found forQ2 production thus confirming the results obtained in a previous decay Dalitz plot analysis of the same reaction. The relative phase behaviour of the 1+(Kϱ) partial waves obtained with the present analysis provides additional confirmation of the resonance interpretation of theQ1 enhancement. Information is also obtained about its production properties and the role played by the Λ polarization in the hypercharge exchange reaction. This is compared with the results obtained in the reactionK−p→(π+π−π0)Λ at 4 GeV/c.
LAMBDA POLARIZATION CALCULATED AS AVERAGE POLARIZATION OF ALL 1 + (K RHO0) PARTIAL WAVES IN THE QLOW(1240) REGION.
SPIN PARITY CONTENT OF (K PI PI) SYSTEM.
CONTRIBUTION TO THE TOTAL JP=1+ INTENSITY FROM THE K* AND RHO ISOBARS.
We have observed ϱ 0 production in e + e − annihilation to hadrons at high energies. The differential cross section at a centre of mass energy W , of 34 GeV, is presented. In the range 0.2< x < 0.7, we measure 0.33 ± 0.06 (stat.) ± 0.07 (syst.), 0.22 ± 0.06 ± 0.05 and 0.22 ± 0.02 ± 0.05 ϱ 0 /event at W = 14, 22 and 34 GeV respectively.
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INTEGRATION OVER RESTRICTED X RANGE.
The elastic electron-neutron cross section has been measured at four-momentum transfers squared (Q2) of 2.5, 4.0, 6.0, 8.0, and 10.0 (GeV/c)2 with use of a deuterium target and detection of the scattered electrons at 10°. The ratio of neutron to proton elastic cross sections decreases with Q2. At high Q2 this trend is inconsistent with the dipole law, form-factor scaling, and many vector dominance models, although it is consistent with some parton models.
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About 15 000 K − Φp events have been collected in the CERN Ω′ spectrometer. A partial-wave decomposition of the K − Φ system is performed. The 1 + SO + wave is dominant. The 0 − P0 + and 2 − P0 + waves are important and show resonant behaviour at ∼ 1.83 GeV (Γ ∼ 0.25 GeV) and ∼ 1.73 GeV (Γ ∼ 0.22 GeV) respectively. The first one can be interpreted as the second radial excitation of the kaon while the second one can be identified as one of the two L mesons.
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PARTIAL WAVE AMPLITUDE SHOWING POSSIBLE EXISTENCE OF L MESON AT 1.73 GEV (WIDTH = 0.22 GEV) AND RADIAL EXCITATION OF THE KAON AT 1.83 GEV (WIDTH = 0.25 GEV).
The inclusive cross sections for the production of high transverse momentum π + and π − mesons in proton-proton interactions have been measured at the highest ISR energy √ s = 63 GeV and at a c.m. production angle of 50°. The cross sections for π + and π − mesons are compared as a function of transverse momentum. It is shown that the inclusive cross section of π − mesons decreases faster than the π + cross section. particle σ ( π ± )/ σ (charged particles) are presented as a function of transverse momentum.
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The reaction e + e − → hadrons has been measured in the ϒ and ϒ′ region using the DASP detector at the DESY storage ring DORIS. The following final results are obtained: R had (9.5 GeV)=3.73±0.16±0.28, Γ ee ( ϒ )=(1.23 ± 0.08 ± 0.12) keV, B μμ ( ϒ )=(3.2±1.3±0.3)%, Γ ee Γ had Γ tot (ϒ′)=(0.55±0.11 ±0.06) keV , and M ( ϒ ′)− M ( ϒ )=(556 ±10) MeV.
CROSS SECTION AROUND UPSILON AND UPSILON PRIME.
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Proton-antiproton elastic scattering at a centre-of-mass energy of 540 GeV was measured in the four-momentum transfer range 0.05 < − t < s .19 GeV 2 . The t -distribution can be fitted by the exponential exp( b ) with b =17.2±1.0 GeV −2 . This result indicates a rapid decrease of the width of the diffraction peak between ISR and Collider energies.
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EXPONENTIAL SLOPE OF FIT TO DN/DT IN REGION 0.05 <-T <0.19 GEV**-2.
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