The angular distributions of K + p and π + p backward elastic scattering have been measured at 5.2 and 6.9 GeV/ c . Backward π - p and K - p elastic scattering were studied at 6.9 GeV/ c . Backward peaks are observed in K + p scattering with an energy dependence of the form s −4 .
No description provided.
We present results of measurements of the differential cross sections for the following elastic-scattering reactions: (i) π + p at 5.2 and 7.0 GeV/ c in the range −1 < u < 0.02 (GeV/ c ) 2 , (ii) π − p at 7.0 GeV/ c in the range −0.7 < u < 0.05 (GeV/ c ) 2 , (iii) K + p at 5.2 and 7.0 GeV/ c in the ranges −1 < t < −0.01 (GeV/ c ) 2 and −1 < u < 0 (GeV/ c ) 2 , and K − p at 7.0 GeV/ c in the range −1 < u < 0 (GeV/ c ) 2 .
No description provided.
No description provided.
SIDE GEOMETRY.
Results are reported on K − -neutron interactions at c.m. energies near 2 GeV. The interactions are dominated by strong production of hyperon resonances, particularly Σ(1385), Λ(1405) and Λ(1520). Production cross sections and angular distributions are given for the Σ(1385), Λ(1405) and Λ(1520) and branching fractions to decay modes observed in the experiment are given for Σ(1385) and Λ(1520). The strong energy dependence of some features of the data suggests that s -channel effects are dominant.
No description provided.
RESONANCE CROSS SECTIONS FOR <K- PI- P> FINAL STATE.
RESONANCE CROSS SECTIONS FOR <AK0 PI- N> FINAL STATE.
Total and differential cross sections are presented for the reactions K − p → K − p and K − p → K o n at 13 points in the c.m. energy range 1915–2168 MeV. An energy-dependent partial-wave analysis is carried out on these data together with the polarisation measurements of Daum et al. [1] and the total cross section measurements [2] within this energy range. The well known Σ(1915), Σ(2030) and Λ(2100) are observed and their resonance parameters measured. Structure is also found in the D 05 and F 07 waves. An SU(3) analysis of the 5 2 + octet, 7 2 + decuplet and 7 2 − singlet gives generally good agreement between theory and experiment except that the elasticity of the Σ(1915) is experimentally rather larger than predicted.
No description provided.
No description provided.
DETERMINED BY NORMALIZING AT ZERO DEG TO TOTAL CROSS SECTIONS VIA THE OPTICAL THEOREM.
The differential cross-sections for the annihilation processes p p→π − π + and p p→K − K + have been measured at an incident laboratory momentum at 5 GeV/ c . Strong backward and forward peaks are observed in the π + π − differential cross-sections while the K + K − cross-section is shown to have a peak only for K − going forward. The annihilation cross-sections are compared with the cross-sections for the crossed channel backward processes π ± p→p π ± and K ± p→pK ± .
No description provided.
No description provided.
The elastic scattering of K ± mesons on protons has been studied at 5 GeV/c. A total of about 500 000 events have been measured in the c.m. angular range 17° < θ cm < 165° corresponding to 0.2 < − t < (GeV/ c ) 2 . We observed a K − p backward peak which we have parametrized as d σ /d u = (0.6 ± 0.2) exp [(3.3 ± 0.6) u ] μb /(GeV/c) 2 , while for the K + p backward peak we find d σ /d u = (17.5 ± 1) exp [(3.6 ± 0.2) u ] μb /(GeV/c) 2 . The K − p cross-section falls to about 0.03 μ b ( GeV /c) 2 around − t = 5 (GeV/ c ) 2 , while the K + p cross-section stays in the vicinity of 0.3 μ b ( GeV /c) 2 in the same t -region. The K + p and K − p differential cross-sections have cross-over points at − t = 0.2, 1.1 and about 3.5 (GeV/ c ) 2 .
No description provided.
No description provided.
We present results of measurements of K ± p and p p elastic scattering and of the annihilation reactions p p →π + π − and p p → K + K − at an incident laboratory momentum of 5 GeV/ c . Nearly complete angular distributions were obtained. Results are also presented for π -meson proton elastic scattering in the momentum transfer ranges 2 < − t < 8 (GeV/ c ) 2 (for π + ) and 0.16 < − t < 7 (GeV/ c ) 2 (for π − ). All measurements were done in one experimental geometry. The measured differential cross sections range from 10 to 10 −5 mb/(GeV/ c ) 2 .
-U = T + 8.486 GEV**2.
THE DATA FOR -T = 7.31 TO 8.45 GEV**2 WERE NORMALIZED TO OTHER EXPERIMENTS.
-U = T + 8.304 GEV**2.
K + p elastic scattering has been measured over nearly the whole angular range at an incident momentum of 10 GeV/ c . The differential cross-section is found to decrease smoothly in the forward direction to - t ≈ 2 (GeV/ c ) 2 , where there is a change in slope, followed by a further decrease to - t ≈ 6 (GeV/ c ) 2 . Around 90° c.m. the cross-section is approximately 1 nb/(GeV/ c ) 2 , which is more than two orders of magnitude lower than at 5 GeV/ c . The backward peak has no structure.
THESE DATA ARE REPORTED MORE FULLY IN C. BAGLIN ET AL., NP B98, 365 (1975).
A partial-wave analysis of the (K ππ ) 0 system produced in the charge exchange reaction K − p →( K 0 π + π − ) n has been made in the mass range 1.04 ⩽ M (K ππ ) < 1.56 GeV c data at 8, 10 and 16 GeV/ c . It was found that in about 2 3 of the cases, the (K ππ ) 0 system is produced in states of unnatural spin-parity, namely J P = 0 − and 1 + ; the rest is in the natural spin-parity state J P = 2 + state is consistent with being all K ∗ (1420). The unnatural spin-parity states are produced mostly (∼ 80% of the events) by natural parity exchange. The facts that unnatural spin-parity states are produced in this non-diffractive channel, with J P = 1 + dominant, and that the exchange responsible for their production is mostly of natural parity, are similar to what was found for the charged (K ππ ) − system in the diffractive reaction K − p→(K ππ ) − p. However, the absolute value and the energy dependence of the cross sections are very different in the two cases.
CORRECTED FOR UNSEEN AK0 DECAY MODES.
ACTUALLY CROSS SECTIONS FOR PRODUCTION IN MASS REGION 1.04 < M(AK0 PI+ PI-) < 1.56 GEV IN THE STATES JP = 1+, 2+ AND 0- RESPECTIVELY.
A partial-wave analysis has been performed on the (K − π − π + ) system produced in the reaction K − p → K − π − π + p at 10 and 16 GeV/ c . In the Q mass region it is found that the two dominant states, K ∗ π and Kπ, both in 1 + S wave, are produced with different polarisations, helicity being approximately conserved in the t -channel for K ∗ π and in the s -channel for Kπ. This is in contradiction with the assumption that the amplitude can be factorised into “production” and “decay” parts, and hence that the two amplitudes are fully coherent. The phase variation of the two states do not indicate simple resonance behaviour. It is concluded that the Q-mass enhancement is composite.
No description provided.
No description provided.
Forum