The production of charged kaon pairs in two-photon interactions has been studied with the ARGUS detector and the topological cross section has been measured. The γγ-widths and interference parameters have been determined for the tensor mesonsf2 (1270),a2 (1318) andf′2 (1525). The helicity structure assumed for the continuum contribution has a significant effect on the result. Upper limits have been obtained for the γγ-widths of the glueball candidate statesf2 (1720) andX (2230).
Data read from graph.. Errors are the square roots of the number of events.
Cross section allowing for spin components JM = 22,20,00. Data read from graph.. Additional overall systematic error 8.4%.
Cross section allowing for spin components JM = 22,00. Data read from graph.. Additional overall systematic error 8.4%.
Two-photon production of the exclusive final statesp\(\bar p\)+nπ (n=0, 1, 2, and 3) has been investigated using the ARGUS detector at thee+e− storage ring DORIS II at DESY. The reactionsγγ→p\(\bar p\)π andγγ→p\(\bar p\)π+π−π0 have been observed for the first time, as have theΔ++ and\(\overline {\Delta ^{ ++ } } \) baryons in the final statep\(\bar p\)π+π−. No evidence was found forΔ++\(\overline {\Delta ^{ ++ } } \) production. Topological cross sections for two-photon production ofp\(\bar p\),p\(\bar p\)π0,p\(\bar p\)π+π− andp\(\bar p\)π+π−π0, as well as the crosssection forγγ→Δ++\(\bar p\)π+π−+c.c., have been measured. Upper limits are given for the cross section forγγ→Δ0\(\overline {\Delta ^0 } \),γγ→Δ++\(\overline {\Delta ^{ ++ } } \) andγγ→Λ\(\bar \Lambda \).
Data read from graph.. Additional overall systematic error 13% not included.
Data read from graph.. Additional overall systematic error 13% not included.
Data read from graph.. Additional overall systematic error 13% not included.
Using the DASP detector at the DESY storage ring DORIS we have continued measuring e + e − annihilations near and on the ϒ(9.46) resonance. From the cross sections for e + e − → μ + μ − and e + e − → hadrons we obtain a μ + μ − branching ratio for the ϒ(9.46) of (2.9 ± 1.3 ± 0.5) %, a leptonic width г ee = (1.35 ± 0.11 ± 0.22) keV and a total width of (47 −15 +37 keV.
VISIBLE HADRONIC CROSS SECTION. PEAK VALUE AT UPSILON IS 10.1 +- 0.7 NB.
No description provided.
The forward cross sections for the reactions π−p→K+Σ− and K−p→π+Σ− have been determined for incident particle momenta in the range of 2.75 to 3.50 GeV/c, and an upper limit was established at 5.00 GeV/c. These measurements show that the double-charge-exchange process π−p→K+Σ− is suppressed by a factor of 1500 at 3 GeV/c relative to the single-exchange reaction π+p→K+Σ+.
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We have measured the reactions π±p→π±p and π+p→K+Σ+ at 5.0 GeV/c in the region 2.2<−t<3.5 (GeV/c)2. We find the minimum cross section of the dip at −t=2.8 (GeV/c)2 in π+p elastic scattering to be 0.16 ± 0.05 μb/GeV2. The π−p differential cross section exhibits similar structure, while the π+p→K+Σ+ channel shows a steady decline in cross section as |t| increases. The polarization of the Σ+ remains large and positive to at least −t=2.8 (GeV/c)2.
No description provided.
No description provided.
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We present data on the reaction K+p→K+p at large angles. Between the forward diffraction peak and the backward peak the cross section is independent of four-momentum transfer but varies with incident momentum.
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The differential cross section for the process p+p→π++d was measured at 5.0 GeVc for a center-of-mass angle of 90°. The experiment was done on the Argonne ZGS with the same apparatus as was used in a recent 90° proton-proton elastic scattering experiment. The extracted proton beam of the ZGS was made to impinge upon a CH2 target. The pion and deuteron were detected by two spectrometers, each containing magnets and a scintillation-counter telescope, in coincidence. The incident beam flux was measured by a radiochemical analysis of the CH2 target. The 90° cross section at 5.0 GeVc was found to be 35±9 nb/sr.
No description provided.
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No description provided.