Measurements of π±p, K±p, pp, and p¯p elastic scattering are presented for incident momenta of 3, 3.65, 5, and 6 GeVc and momentum transfers typically 0.03 to 1.8 GeV2. The angle and momentum of the scattered particle were measured with the Argonne Effective Mass Spectrometer for 300 000 events, yielding 930 cross-section values with an uncertainty in absolute normalization of ±4%. Only the K+ and proton data show any significant change in slope of the forward diffraction peak with incident momentum. The particle-antiparticle crossover positions are consistent with no energy dependence, average values being 0.14 ± 0.03, 0.190 ± 0.006, and 0.162 ± 0.004 GeV2 for π' s, K' s, and protons, respectively; these errors reflect both statistics and the ±1.5% uncertainty in particle-antiparticle relative normalization. Differences between particle and antiparticle cross sections isolate interference terms between amplitudes of opposite C parity in the t channel; these differences indicate that the imaginary part of the odd-C nonflip-helicity amplitude has a J0(r(−t)12) structure for −t<0.8 GeV2, as predicted by strong absorption models. The cross-section differences for K± and proton-antiproton are in qualitative agreement with the predictions of ω universality, the agreement improving with increasing energy. The corresponding quark-model predictions relating the π± and K± differences failed by more than a factor of 2. We have combined our π± cross sections with other data to better determine the πN amplitudes in a model-independent way; results of this analysis are presented.
No description provided.
No description provided.
No description provided.
The differential cross section for π − p → π 0 n has been measured in the t range 1.8 ⩽ | t | ⩽ 8.2 (GeV/ c ) 2 by a counter-spark chamber experiment detecting the neutron and both π 0 decay photons. A broad minimum was found, centered at | t | = 5.2 (GeV/ c ) 2 .
No description provided.
The reaction e − + p → e − + p + η has been studied in the region of the S 11 (1535)-resonance by detecting the recoil proton in coincidence with the scattered electron. The reaction has been observed at three four-momentum transfers of the virtual photon: q 2 = 0.2, 0.28 and 0.4 (GeV/ c ). First results of the differential cross section measurements are given and compared with quark model calculations.
No description provided.
No description provided.
None
TWO EVENTS SEEN WITH MASSES 800 +- 90 MEV AND 1400 +- 90 MEV. THE FIRST WHEN INTERPRETED AS ETAPRIME PRODUCTION GIVES A WIDTH OF 11, +15, -8 KEV FOR ETAPRIME --> 2GAMMA USING THE EQUIVALENT PHOTON APPROXIMATION.
None
HADRONIC WIDTH IS 26 +- 11 KEV, ELECTRON DECAY WIDTH IS 3.4 +- 1.2 KEV AND MUON DECAY WIDTH IS 2.4 +- 1.1 KEV.
We give the cross-sections of quasi-two-body reactions produced in K−-proton interactions at 13 different energies in the centreof-mass energy range 1.915 to 2.168 GeV.
No description provided.
The reaction K−n→Σ−η has been studied near threshold. The production angular distribution and the cross-section as a function of energy were measured. The combined angular distributions of this experiment and two previous ones suggest that aJ=1/2 amplitude dominates in Σ−η production. Our cross-section can be fitted with a Σ−1η resonance of mass 1785±12 and width 89±33, or it can be fitted in a zero-effective-range scattering approximation with a scattering length of (0.92±0.12)±i(0.04±0.28) fm.
No description provided.
CROSS SECTION NEAR THRESHOLD CORRESPONDS TO A SCATTERING LENGTH OF (0.92 +- 0.12) +- I*(0.04 +- 0.28) FM.
PRODUCTION ANGULAR DISTRIBUTION - ASSUMED SYMMETRIC IN COS(THETA).
Data on\(\bar pn\) annihilation at rest into π−ϕ are presented. The production frequency, mass, width and decay angular distribution of the ϕ-meson are measured.
RELATIVE PRODUCTION FREQUENCY OF PHI.
New results on the multihadron production by electron and positron beams colliding with a total energy of up to 3 GeV are reported. Disregarding possible kaon final states, the ratio σ mh / σ μμ of the total multihadron cross-section to the point-like cross section for process e + e − → μ + μ − has an average value of 1.58 ± 0.25 in the energy interval 2.6–3.0 GeV. The average charged multiplicity over this energy range is 〈 n c 〉 = 2.9 ± 0.3.
AT A MEAN ENERGY OF 2.85 GEV, THE AVERAGE MULTIHADRON CROSS SECTION IS 16.4 +- 2.6 NB (R = 1.58 +- 0.25).
The K − p reactions with final states Λπ 0 , Σ 0 π 0 , Λπ 0 π 0 , Λη and Σ 0 η have been studied at 14 momenta between 685 and 934 MeV/ c using optical spark chambers. The charged decay products of the Λ are detected by low mass spark chambers while γ-rays from π 0 and Σ 0 decays are detected in high mass chambers. Approximately 250 000 photographs were analysed from which partial and differential cross sections were determined. These results are presented with an energy dependent, single channel partial-wave analysis.
No description provided.
No description provided.
No description provided.
Forum