The K L o p → K S o p differential and total cross-section and the forward scattering amplitude phase φ have been measured in the 1.5 to 2.3 GeV centre of mass energy range. The data is compared with predictions based on recent K ± N phase shift solutions. Best agreement is found for K + N solutions which do not warrant an I=0 P 1 2 exotic Z ∗ o (1800) baryon.
No description provided.
No description provided.
The reaction e p→e'p π 0 has been measured at W =2.55 GeV a fixed electron scattering angle of 10.3°. Two magnetic spectrometers and a lead glass hodoscope were used to detect all four final state particles. Electroproduction cross sections in the t range −0.15 to −1.4 (GeV/ c ) 2 at q 2 = −0.22, −0.55 and −0.85 (GeV/ c ) 2 are presented. Above | t |=0.6 (GeV/ c ) 2 the cross sections are considerably smaller than those for photoproduction.
NUMERICAL VALUES MEASURED FROM GRAPH IN PREPRINT BY TDBW.
A search for narrow resonances in the reaction e + e − → hadrons in the mass regions 1915–2345 MeV and 2970–3090 MeV has been perforned at ADONE, the Frascati storage ring. With 90% confidence level our data exclude the production of narrow resonances with integrated cross section larger than 20% of the integrated cross section for production of the J/Ψ (3100 MeV).
No description provided.
We have searched for possible narrow resonances produced in e + e − annihilation at Adone, in the mass regions 1910–2545 MeV and 2970–3090 MeV. No evidence has been found for narrow resonances, within the sensitivity of the present work: we deduce an upper limit on the energy integrated resonant cross section of about 10% of the J/ψ(3100) corresponding value.
No description provided.
The reactions e + e − → hadrons and e + e + e − →e + e − have been studied at the J/gY (3100) resonance). The relative weights of the topological cross sections for fixed charged multiplicity are σ 2 =(32±5)%, σ 4 =(49±8)%, σ 6 =(18±3)%, and σ 8 =(1±0.6)%. The average pion multiplicities are 〈 n ch 〉=3.8±0.3 and 〈n π o 〉=3.1±0.8 . The decay widths are Γ e =(4.6±0.8) keV, Γ h =(59±24) keV, and Γ =(68±26) keV.
CROSS SECTION AROUND RESONANCE.
CROSS SECTION JUST BELOW J/PSI.
MULTIPLICITY AT J/PSI.
New data from a 600 000 picture exposure of the BNL 31 inch hydrogen bubble chamber to a separated antiproton beam have been analyzed to try to determine if the π + π − π + π − or π + π − π + π − π 0 final states contribute any broad or narrow structure in the T(2190) region. The resonance channel fractions determined by maximum likelihood fits are all consistent with smooth behavior through the T-region and therefore there is no significant evidence that any of these resonance channels contributes to the broad bump in the total cross section. The errors on some of the fractions, however, limit the sensitivity to ∼ 0.5 mb for enhancements in these channels.
RESONANCE CHANNEL PERCENTAGES FROM FIT TO PI+ PI- PI+ PI- FINAL STATE.
RESONANCE CHANNEL PERCENTAGES FROM FIT TO PI+ PI- PI+ PI- PI0 FINAL STATE.
The results are presented of two partial-wave analyses of the (3π) − system in 30 000 events of the reaction π − p → π − π − π + p at 11.2 GeV/ c . Both techniques incorporate the assumptions of the isobar model and are (a) the University of Illinois program which fits in terms of the (3π) density matrix elements and (b) an amplitude parametrisaton including possible effects of both spin non-flip and spin flip at the baryon vertex. The results obtained with these independent programs are found to be very close.
NORMALIZED TO A TOTAL REACTION CROSS SECTION OF 1.17 +- 0.24 MB. ALL QUOTED CROSS SECTIONS ARE FOR INTEGRATED BREIT-WIGNERS.
A2 2+D-WAVE FOR 1.2 < M(3PI) < 1.4 GEV. THE FIRST THREE COMBINATIONS OF DENSITY MATRIX ELEMENTS ARE FOR NATURAL PARITY EXCHANGE, AND THE REMAINDER UNNATURAL.
Experimental results for the cross-sections, the effectivemass distributions, the angular distributions and correlations are presented for the reaction\(\bar p\)p → 3π−3π+. All the multipion mass distributions and the ππ angular correlations are described in terms of a final-state interaction model including theδ00 andδ11 ππ phase shifts, as well as an A2 effect.
No description provided.
INCOHERENT BRIET-WIGNER FIT TO 3PI- 3PI+ CHANNEL.
Differential cross-section measurements for π − p → γ n, consisting of three angular distributions at 618, 676 and 718 MeV/ c , and the energy dependence at θ γ = 90° for seven incident pion momenta between 502 and 888 MeV/ c , are presented. Our data qualitatively support recent multipole analyses. Agreement with the Scheffler et al. results for the inverse reaction, γ n → π − p, using a ( π − -recoil p) coincidence technique is good excluding a large violation of time reversal invariance. The agreement with γ n → π − p data obtained using the R ( π − / π + ) ratio technique or a deuterium bubble chamber is only qualitative.
Axis error includes +- 6.6/6.6 contribution.
Axis error includes +- 6.2/6.2 contribution.
Axis error includes +- 6.0/6.0 contribution.
Angular distributions of the differential cross section for the reaction γ +p→ π 0 +p have been measured at the Bonn 2.5 GeV Synchrotron at c.m. angles between 0° and 65° in the energy range from 1.3 GeV to 2.2 GeV. The π 0 mesons were detected by their two decay photons. The data are compared with data of other laboratories and the Metcalf-Walker analysis.
No description provided.
Forum