Inclusive production of Σ + , Σ − and Σ 0 hyperons in K − p interactions at 14.3 GeV/ c has been studied and compared to Λ production. Cross sections are presented as a function of longitudinal and transverse momenta and compared to the pp → Σ + + anything data.
No description provided.
No description provided.
No description provided.
We have measured small angle elastic pion-proton scattering in 40 and 50 GeV c π − beams at Serpukhov. Analysis of the data in the Coulomb interference region yields a value for the ratio of the real to the imaginary part of the strong amplitude, ϱ (0)=−0.074 ± 0.033 at 40 GeV/ c and ϱ (0)=−0.006 ±0.026 at 50 GeV/ c
STATISTICAL ERRORS ONLY.
STATISTICAL ERRORS ONLY.
The backward angular distributions obtained in an experiment at the Zero Gradient Synchrotron of Argonne National Laboratory were used to systematically study the energy dependence of the 180° differential cross section for π+p elastic scattering in the center-of-mass energy region from 2159 to 3487 MeV. At each of 38 incident pion momenta between 2.0 and 6.0 GeV/c, a focusing spectrometer and scintillation counter hodoscopes were used to obtain differential cross sections for typically five pion scattering angles from 141° to 173° in the laboratory. Values for dσdΩ at 180° were then obtained by extrapolation. A resonance model and an interference model were used to perform fits to the energy dependence of dσdΩ (180°). Both models led to good fits to our data and yielded values for the masses, widths, parities, and the product of spin and elasticity for the Δ(2200), Δ(2420), Δ(2850), and Δ(3230) resonances. Our data confirm the existence of the Δ(3230) and require the negative-parity Δ(2200).
No description provided.
No description provided.
No description provided.
In an exposure of the Fermi National Accelerator Laboratory 30-in. bubble chamber to a beam of 205-GeV/c protons, we have determined total and differential cross sections for the inclusive reactions p+p→γ+X, π0+X, (K0K¯0)+X, Λ+X. Invariant distributions in x indicate that for γ, K0, Λ production, scaling has set in somewhere before 69 GeV. The γ differential cross sections are consistent with the relation dσdPu(π0)=12[dσdPu(π+)+dσdPu(π−)] for all Pu, where Pu=PL* or P⊥. The differential cross sections for Λ and K0 production indicate a break in the distribution at |t−tmin|=1.5(GeVc)2 and 0.5(GeVc)2, respectively. The Λ polarization is found to be - (0.25 ± 0.26), consistent with zero throughout the x region.
No description provided.
A comparison is made of the properties and production mechanisms of the π + ω and K − ω systems produced in the reactions π + p → π + ω p at 4, 5, 8 and 16 GeV/ c and K − p → K − ω p at 10 and 16 GeV/ c . In the π + ω case apeak is observed at 1.23 GeV (the B meson), while the K − ω mass distribution has a threshold enhancement. The cross section of the low mass (<2.0 GeV) π + ω system falls as p lab −2 , while that of the low mass (<2.0 GeV) K − ω system is almost constant with energy, indicating diffractive production of the K − ω system, but not of the πω system. Using a modified version of the Illinois partial-wave analysis program, it is found that the K − ω system is dominantly produced in the J P = 1 + state with small contributions of 0 − and 2 + , mainly by natural parity exchange - as is found for reactions such as K − p → (K − π + π − )p which are predominantly diffractive. For the π + ω system in the B mass region, J P = 1 + states, produced mainly by natural parity exchange are found; the contributions of 0 − P, 1 − P, 2 − P and 2 + D are consistent with zero. The 1 + D state occurs in the π + ω case but not in the K − ω system, nor in the K ππ − system produced in the K − p → K ππ p reaction.
No description provided.
No description provided.
FROM BREIT-WIGNER FIT TO B EVENTS AND CORRECTED FOR UNSEEN OMEGA DECAY MODES.
As part of a program to determine proton-proton elastic-scattering amplitudes, we have measured the spin-spin correlation parameter CNN at 6 GeV/c. Measurements were made over the |t| range of 0.08 to 1.4 (GeV/c)2 using a polarized beam and a polarized target at the Argonne National Laboratory Zero Gradient Synchrotron.
No description provided.
In an exposure of the Argonne National Laboratory 12-foot hydrogen bubble chamber to a beam of 12.4-GeV/c protons, we have measured the total and differential cross sections for the inclusive reactions p+p→γ+X, π0+X, K0+X, and Λ+X, as well as estimates for the inclusive η and Σ0 cross sections. We present the average number of π0, K0, and Λ as a function of the associated charge multiplicity. We observe that the average charge multiplicity in pp collisions is the same whether or not a π0, K0, or Λ is also produced in the interaction. Invariant cross sections are presented as a function of PT2 and x, the Feynman scaling variable. The π0 differential cross sections are consistent with the relation dσdP(π0)=12[dσdP(π+)+dσdP(π−)] for all pion momenta P. The differential cross section for Λ production indicates a break in the distribution of |t−tmin|=1.4 (GeV/c)2. The polarization of the Λ's is found to be consistent with zero for all values of x.
No description provided.
Differential cross sections for π+p elastic scattering in the momentum region 1.2 to 2.3 GeV/c are presented for the center-of-mass angular range 0.9>cosθ>−0.9. Typically, 50 000 events were obtained at each of 16 momenta using magnetostrictive-readout wire spark chambers to detect the particles scattered from a liquid hydrogen target. The results are compared to those of the CERN-71 phase-shift analysis. The well-known dips at t≅−0.7 (GeV/c)2 and at u′=−0.2 (GeV/c)2 are observed. In addition, structure is seen at constant u′=−1.3 (GeV/c)2. The results of a pion attenuation study in iron are also presented.
No description provided.
No description provided.
No description provided.
The polarized target asymmetry in the reaction γp→π°p has been measured at c.m. angles around 100° for photon energies between 0.4 and 1.0 GeV by detecting both the recoil proton and the π°. The result is compared with recent analyses.
No description provided.
The asymmetry of the cross sections for the photoproduction of π + mesons on polarized protons γ + p↑ → π + + n has been studied in the four-momentum transfer range 0.1 ⩽ | t | ⩽ 1.25 (GeV/ c ) 2 for photon energies of 2.5, 3.4 and 5.0 GeV. The measurements were carried out on a polarized butanol target. Both particles in the final state were detected: the pion by a magnetic spectrometer, the recoil nucleon in a scintillation counter matrix. The asymmetry was found to be negative with values around −0.4.
No description provided.
No description provided.
No description provided.
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