Results of two spark chamber experiments on A 2 − production in the reaction π − p → K − K S 0 (→ π + π − )p at 9.8 and 18.8 GeV are presented. Decay angular distributions and differential cross sections are given, and the energy dependence of the cross section σ [ π − p → A 2 − (→ K − K 0 )p] is compared with results from π − p → A 2 − (→ 3 π )p.
FITS WITH CONSTANT BACKGROUNDS. A TWO-PARAMETER LINEAR BACKGROUND GIVES MUCH LARGER ERRORS.
INTEGRATED OVER M(K AK) = 1.20 TO 1.42 GEV.
No description provided.
None
FOR THE FPRIME A PURE 2+ STATE IS ASSUMED AND ONLY JZ=+1,0,-1 CONTRIBUTIONS ARE CONSIDERED.
No description provided.
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The reaction p p → K ∗ K does not exhibit any s -channel resonance effect between 1 and 2.5 GeV/ c . On the contrary, the data on p p → K ∗∓ K ± are compatible with an exchange mechanism in the t - and u -channels above 1.5 GeV/ c . Strong similarities are found with p p → K − K + and K ∗− K ∗+ . The polarisation of K ∗± is given. The reaction p p → K ∗0 K 0 vanishes above 1.5 GeV/ c
No description provided.
LEG(L=0) = SIG/(4*PI).
LEG(L=0) = SIG/(4*PI).
We have measured the reaction γ p → p π + π − in the DESY 1 m Streamer Chamber. The dominant ϱ o production is analyzed in terms of various models.
No description provided.
FOR ALL EVENTS.
FOR ALL TWO PION EVENTS.
We have investigated the final states K ∗0 (890)Σ, K ∗0 (890)Σ 0 and K ∗0 (890) Y 1 ∗0 (1385) produced in π − p interactions at 3.93 GeV/ c . We present the differential cross sections and spin density matrix elements for the resonances as functions of momentum transfer, as well as the gL and Σ 0 polarizations. The Σ 0 polarization is found to be positive and maximal. An amplitude analysis is performed for the K ∗ Λ and K ∗ Σ 0 reactions, and it is found that one natural parity transversity amplitude is dominant for the latter.
No description provided.
No description provided.
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We have measured 618 K + p → π + K S 0 p events at 12.7 GeV/ c incident lab momentum, mass range 790 ⩽ m π + K s 0 ⩽ 990 MeV and t range 0.01 ⩽ − t ⩽ 0.60 (GeV/ c ) 2 . The π + K S 0 mass spectrum is dominated by the K ∗+ (892) resonance and a Breit-Wigner fit yields a mass m = 893.5 ± 1.1 MeV and a width Γ = 33.2 ± 4.1 MeV which is much narrower than measured hitherto. The t distribution of K ∗+ (892) events shows a dip in the forward direction and an exponential fall off thereafter, consistent with dominance of helicity flip amplitudes. The spin density matrix is almost saturated by ρ 11 and ρ 1−1 which are very close to their maximum allowed value of 1 2 throughout the measured t range except in the very forward direction where ρ 00 and Re ρ 10 deviate from zero. Natural parity exchanges, therefore, dominate with unnatural parity exchanges being restricted to a small region in the forward direction. A Regge pole analysis of the differential cross sections of the present measurement in conjunction with previously measured total cross sections supports the f-coupled-pomeron hypothesis.
SUBTRACTED BACKGROUND IS PHASE SPACE.
SUBTRACTED BACKGROUND IS AN INCOHERENT S-WAVE WITH EXPONENTIAL T-DEPENDENCE WITH SLOPE OF 6 GEV**-2.
Axis error includes +- 15/15 contribution.
A study of the reaction π − p → X − p based on 1.27 × 10 6 events, corresponding to a mean sensitivity of 200 events/μb, is presented. Properties of the exclusive channels π − p → π − π 0 p, π + π − π − p, π + π − π − π 0 p, π + π + π − π − π − p and π + π + π − π − π − π 0 p are discussed.
No description provided.
No description provided.
No description provided.
The reaction π − p → A − 2 p at 3.9 GeV/ c incident momentum is studied using data corresponding to the ϱ ° π − , ηπ − and K δ s K − decay modes of the A − 2 . Unnatural parity exchange is found to be important at this energy. The natural parity exchange component of the differential cross section exhibits structure at t ′ ≈ GeV 2 .
CORRECTED FOR ALL A2(1310)- DECAY MODES.
No description provided.
<RHO0 PI-> DATA.
We have investigated the ρ-meson production mechanism in the three reactions π±p→ρ±p and π−p→ρ0n at 3.9 GeV/c (s=8.2 GeV2) using the prism-plot technique. Differential cross sections at all momentum transfers are presented. A significant backward peak has been found in all three reactions. The differential cross sections for these backward peaks are given and are compared with the equivalent pion elastic and charge-exchange cross sections in the backward direction. Using a linear combination of the three differential cross sections we have isolated the I=0 exchange contribution in the forward direction. This differential cross section has a zero at −t=0.45 (GeV/c)2 and is fitted by the dual absorptive model of Harari with an interaction radius of ∼ 1.2 F. The total I=0 cross section is calculated and compared with similarly determined cross sections at higher momenta. An analysis of the properties of the other possible spin-parity exchanges is also presented.
SLOPE FITTED OVER 0.05 < -T < 0.3 GEV**2.
No description provided.
No description provided.
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.
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