An experiment was done using the new accelerated polarized proton beam at the Argonne National Laboratory zero-gradient synchrotron and a polarized proton target. The total cross section for proton-proton scattering at 3.5 GeV/c was measured in the spin states ↑↑ and ↑↓ perpendicular to the beam direction. The two cross sections were found to be equal within the experimental error of ±5%.
TOTAL CROSS SECTION DIFFERENCE FOR PURE TRANSVERSE SPIN STATES.
We have measured the polarization of the recoil proton in the reactions γp→π0p and γp→γp for incident photon energies between 3 and 7 GeV, and t values from -0.2 to -0.65 GeV2. The polarization in neutral-pion production varies from 0 to -1 over this range. Contrary to expectation, it does not agree completely with the polarized-target asymmetry.
No description provided.
The differential cross section for π+p elastic scattering has been measured at 13.8 GeVc for 0.7<|t|<3.8(GeVc)2. The cross section is found to be equal to that previously obtained for π−p elastic scattering, except in the region |t|=2.8 (GeVc)2, where the π+p data do not show the prominent dip observed in π−p scattering. Data have also been obtained for 13.8−GeVc K+p elastic scattering for 0.8<|t|<2.2 (GeVc)2.
No description provided.
No description provided.
We have measured the ratio of the cross section for γ+n→π0+n to the cross section for γ+p→π0+p at 4.7 and 8.2 GeV. The measurements were made by detecting the recoil nucleons in coincidence with the decay γ rays of the π0's produced from a deuterium target. At 4.7 GeV the cross-section ratio, R≡σ(γ+n→π0+n)σ(γ+p→π0+p), is less than 1.0 at low t, with an indication of a dip at about t=−0.7(GeVc)2, and rises to 1.0 at high t. The ratios at the higher energy have less structure and are uniformly closer to 1.0.
No description provided.
No description provided.
From analysis of V0 events observed in an exposure of the National Accelerator Laboratory 30-in. bubble chamber to 303−GeVc protons, we obtain these results: (1) 〈nπ0〉 rises approximately linearly with n-, implying strong coupling of neutral and charged pions, while 〈nKS0〉 is less coupled to n; (2) γ, KS0, and Λ0 production cross sections are approaching a scaling limit by 303 GeVc; (3) within the limited statistics, dσdy is flat in the central region for KS0 and low-multiplicity γ events.
No description provided.
Momentum spectra for forward Σ− production on beryllium by protons of momentum 25.8 and 29.4 GeVc are presented. Data for the two primary proton momenta are compared for scaling behavior in the invariant cross section. In addition, the observed single-particle momentum distributions are compared with single-particle spectra from other inclusive reactions initiated by protons.
No description provided.
No description provided.
In an experiment at the Argonne Zero-Gradient Synchrotron we have measured values of the polarization parameter P(t) in the elastic scattering of negative pions, positive pions, positive kaons, and protons on protons at several incident laboratory momenta from 2.50 to 5.15 GeVc, and for values of the momentum transfer variable −t from 0.2 to 2.0 (GeVc)2. The final results from p−p elastic scattering presented here extend our knowledge of the polarization to much larger values of −t than the results of previous measurements. Outstanding features revealed by these polarization data include (1) the development of a dip at about −t=0.7 (GeVc)2, with (2) a substantial secondary peak at larger values of −t and (3) the gradual diminution of the maximum polarization with increasing energy. It is possible to fit the t dependence of the experimental results with a simple model. The energy dependence of the polarized cross sections is also discussed.
No description provided.
No description provided.
No description provided.
We present differential and total cross sections for two reactions: π−p→K0Λ and π−p→K0Σ0. The incident pion momenta were 8, 10.7, and 15.7 GeVc. The results are based on an analysis of approximately 22 600 events of the two reactions where the π+ and π− from the decay of the KS0 were detected in the forward leg of the Double Vee Magnetic Spectrometer. The separation of Λ recoils from Σ0 recoils was accomplished by the missing-mass technique.
No description provided.
No description provided.
No description provided.
We have studied η′ production using a π+ beam incident on deuterium in the 72-in. bubble chamber, with beam momenta from 1.1 to 2.4 GeVc. Cross sections for reactions leading to five- and six-pronged final states are presented. We observe η′ production in the reaction π+d→ppη′, with the decay mode η′→π+π−η. The cross section for π+n→pη′ (studied in the impulse approximation) is observed to rise to a maximum of about 100 μb at 2.2-GeV c.m. energy. The production angular distribution develops peripheral peaking with increasing energy.
No description provided.
Results from the study of reactions (1) K−d→K−π−π+d and (2) K−d→K−π−π+nps at 7.3 GeV/c are presented. The interactions are dominated by the production of K*(890), ρ(765), Q(1200−1450), and D*(2200) in (1) and Δ−(1236) in (2). Observation of ρ(765) and its possible source as a misidentified K*(890) is discussed. Evidence is observed of splitting of the Q into two resonances with masses and widths (in MeV) M1=1228±21, Γ1=111±33, M2=1414±15, and Γ2=89±24, L(1775) is observed in (1). An off-shell one-pion-exchange-model calculation is compared to (2). Cross sections and branching ratios of the Q resonances are estimated on the basis of the model.
Q (OR K(A)) CROSS SECTIONS MODEL-DEPENDENT WITH BACKGROUND UNSUBTRACTED.
Forum