We present the results and the analysis of a high-statistics experiment to study A 2 and g production in the reaction π − p→K − K S 0 p at 10 GeV/ c . In each resonance region we perform a moment analysis of the data, and from the moments we determine the production amplitudes as a function of t . We find A 2 production proceeds dominantly by natural-parity (pomeron and f) exchange. We compare A 2 and diffractive K ∗ (1420) production. We find g production proceeds by π and ω exchanges; we determine the g → K K branching ratio.
No description provided.
No description provided.
We have measured the forward production spectra of various neutral particles produced by π−, K−, p¯, and p at 200 GeV/c, and by π− at 290 GeV/c incident on a Be target. The salient features of these measurements are (1) copious production of KSo at large Feynman xL for incident π− and K−, (2) production of roughly equal fluxes of Λ0 and Λ¯0 for incident π−, and (3) close similarity of the following spectra: π−→n and K−→Λ0; π−→Λ0, π−→Λ¯0, and p→KS0; π−→KS0 and p→Λ0. The overall features of the various distributions seem to agree with the ideas of dimensional counting presented in the constituent-interchange model of quark collisions. Results are presented in terms of the invariant cross section Ed3σ(xL, PT=0)dp3 per Be nucleus for each inclusive reaction.
No description provided.
No description provided.
No description provided.
The photon total cross section on protons has been measured with high precision in the Fermilab tagged-photon beam for photon energies from 18 to 185 GeV. The cross section decreases to a broad minimum near 40 GeV, and then rises by about 4 μb over the remainder of the range. A ρ+ω+ϕ vector-dominance model (normalized to low-energy data) falls below the high-energy results by 2 to 6 μb, suggesting a contribution from charm-anticharm states.
No description provided.
No description provided.
An experiment using the PLUTO detector has observed the formation of a narrow, high mass, resonance in e + e − annihilations at the DORIS storage ring. The mass is determined to be 9.46±0.01 GeV which is consistent with that of the Upsilon. The gaussian width σ is observed as 8±1 MeV and is equal to the DORIS energy resolution. This suggests that the resonance is a bound state of a new heavy quark-antiquark pair. An electronic width Γ ee =1.3±0.4 keV was obtained. In standard theoretical models, this favors a quark charge assignment of 1 3 .
No description provided.
We present the observation of a J P = 4 + , I G = 1 − state in the reaction π − p → K S 0 K − p at 10 GeV/ c measured with a non-magnetic spectrometer at the CERN proton synchrotron (PS). A spherical harmonics moments analysis of the K S 0 K − system shows a signal at ∼ 1900 MeV in the 〈 Y 7 0 〉 and 〈 Y 8 0 〉 moments, indicative of a spin 4.
No description provided.
We perform an amplitude analysis of 10 GeV/ c π − p → K − K S 0 p data as a function of K − K 0 mass from threshold up to 2 GeV. We find that the A 2 and g resonances are produced dominantly by natural and unnatural parity exchange, respectively, and we determine their resonance parameters. We present further evidence for the I = 1, 4 + state A 2 ∗ (1900), in particular by isolating interference effects. The structure of S-wave K − K 0 production suggests an I = 1, 0 + state just below 1300 MeV of width about 250 MeV.
CROSS SECTIONS FROM FITTING MASS SPECTRUM. THE RESONANT AMPLITUDE CONTRIBUTIONS ALSO GIVEN IN PAPER.
For the first time, the line reversed reactions π + p→K + Σ + and K − p→ π − Σ + have been studied in the same apparatus. We present the differential cross sections and polarizations over a large t range and at two momenta, 7.0 and 10.1 GeV/ c . The differential cross sections as a function of t are shown for the first time to cross over. Going from the lower to the higher momentum, the differences in cross section between the two reactions diminish at low | t | by about a factor 2. We find large polarizations of opposite sign for the two reactions. The momentum dependence, presented in the form of α eff ( t ) for the t range 0 to −2 (GeV/ c ) 2 , is compared with the expectations from the K ∗ −K ∗∗ trajectory.
-TMIN = 0.0100 GEV**2.
-TMIN = -0.0087 GEV**2.
-TMIN = 0.0067 GEV**2.
The proton polarization in the γ d → pn reaction has been measured at a c.m. angle of 90° and photon energies between 350 and 700 MeV, using a carbon polarimeter. The magnitude of the polarization shows a sharp energy dependence with a peak of about −80% at around 500–550 MeV. This feature cannot be explained by conventional models and seems to indicate a new mechanism in the dibaryon system.
AROUND THETA OF 90 DEG.
The reaction p p → π − π + has been studied at 10.1 GeV/ c in the − t interval from 0.15 to 1.5 (GeV/ c ) 2 . A line-reversal comparison with backward elastic scattering π + p → p π + shows good agreement for − t > 0.3 (GeV/ c ) 2 .
No description provided.
No description provided.
The target asymmetry for the reaction γ p → K + Λ 0 was measured at the Bonn 2.5 GeV synchroton. Data were taken at a fixed kaon c.m. angle of 90° and at photon energies between 1.1 and 1.3 GeV. The kaons were detected in a large aperture magnetic spectrometer.
5 PCT TARGET POLARIZATION UNCERTAINTY INCLUDED IN QUOTED ERRORS.
Forum