At an incident kaon momentum of 2.66 GeV/ c we have measured the total and elastic cross sections to be 30.2 and 5.70 mb respectively. The elastic scattering angular distribution is dominated by a single diffraction peak; and when this peak is fit to an exponential in momentum transfer t , the first order term is both necessary and sufficient. This fit evaluated at t =0 is consistent with a purely imaginary forward scattering amplitude. Our data when compared with that of others indicates no shrinkage of the diffraction peak. The entire angular distribution was also fit to a Legendre series, with order 9 being required to represent the data.
Axis error includes +- 0.0/0.0 contribution (?////).
Final states π − Σ + , π + Σ − , π o Λ and ηΛ were studied for K − p reactions at 3.95 GeV/ c . Cross sections, angular distributions and polarizations are presented. Data for π − Σ + and π o Λ production are compared to the line-reversed πp reactions at the same beam momentum. Baryon-exchange peaks are presented for the Σ + π − , Σ − π + and Λπ o final states.
No description provided.
No description provided.
No description provided.
We present a measurement of the total cross section for γγ→hadrons, with one photon quasireal and the other a spacelike photon of mass squared −Q2. Results are presented as a function of Q2 and the γγ center-of-mass energy W, with the Q2 range extending from 0.2 to 60 GeV2, and W in the range from 2 to 10 GeV. The data were taken with the TPC/Two-Gamma facility at the SLAC e+e− storage ring PEP, which was operated at a beam energy of 14.5 GeV. The cross section exhibits a gentle falloff with increasing W. Its Q2 dependence is shown to be well described by an incoherent sum of vector-meson and pointlike scattering over most of the observed W range. Agreement at high Q2 is improved if a minimum-pT cutoff (motivated by QCD) is imposed on the pointlike contribution.
Errors are statistical only.
Errors are statistical only.
Errors are statistical only.
In an experiment with the 1.5 m bubble chamber at the Rutherford Laboratory, the reaction K + d→K 0 pp has been studied at beam momenta of 2.2, 2.45 and 2.7 GeV/ c . The cross section for the reaction K + n→K 0 p has been estimated and found to be approximately twice that of the line-reversed reaction K − p → K 0 n at comparable energies. An SU(3) sum rule, due to Barger and Cline, has been tested and found not to be valid in this momentum range. The differential cross section for K + n→K 0 p has also been measured and a determination made of the imaginary to real ratio of the forward amplitude, using the optical theorem. Implications of these, and other results, for various Regge models are briefly discussed.
No description provided.
No description provided.
Results are given from a study of 15 518 events of the reaction K + d → K + π − pp. The K + π − spin density matrix and the constraints imposed on it by positivity have been studied. Analyses of K + π − → K + π − elastic scattering have been carried out using methods developed by Estabrooks and Martin and Ochs and Wagner for the analogous case of ππ scattering. Results are found to be in agreement with earlier K π scattering studies using the reaction K + p → K + π − Δ ++ at much higher energies. The S-wave scattering length is found to be in agreement with the prediction of current algebra.
No description provided.
We have studied the 2 π 0 final states in the reaction π + d → π 0 π 0 p(p) at 2.15 GeV/ c in a 2 million picture exposure of the PPA rapid cycling deuterium bubble chamber. Two tantalum plates were added to the bubble chamber to convert γ rays which were kinematically constrained to a 2 π 0 hypothesis. The 2 π 0 mass spectrum is observed to saturate s-wave unitarity in the ππ mass region between 0.6 and 0.9 GeV/ c 2 , clearly favoring the ‘up-down’ or broad resonance solution for s-wave, I = 0, ππ scattering.
No description provided.
We have studied backward baryon and meson production in π−p→pπ+π−π− at 8.0 GeV/c using a streamer chamber triggered by the detection of a fast forward proton. Our data sample (1227 events) displays prominent N*ρ and N*f quasi-two-body production. These states are investigated with regard to the peripheral nature of the production mechanism and sequential decay of the excited baryon and meson systems. The quasi-two-body production of N*ρ and N*f intermediate states is consistent with u-channel proton exchange as the dominant production mechanism. In the π+π−π− mass distribution we observe a 3- to 4- standard-deviation enhancement at M3π=1897±17 MeV/c2 with full width at half maximum = 110 ± 82 MeV/c2, but find no but find no evidence for backward A1 or A2 production. We observe Δ++(1232) production in the pπ+ effective mass distribution.
THESE VALUES ASSUME ONLY RHO(11) IS NON-ZERO. VALUES FOR OTHER RHO(MM) ARE QUOTED IN PAPER. SIG ERRORS INCLUDE OVER-ALL NORMALIZATION UNCERTAINTY, BUT NO BACKGROUND CORRECTIONS HAVE BEEN MADE.
STATISTICAL ERRORS ONLY, NO BACKGROUND CORRECTION.
STATISTICAL ERRORS ONLY, NO BACKGROUND CORRECTION.
The ratio of neutral-current to charged-current interactions is measured to be 0.30±0.03 for isoscalar targets, in good agreement with the results of previous experiments. Two independent methods are employed for isolating neutral-current events, one based on hadronic interactions, and the other on the momentum transverse to the hadron shower. The ratio of neutral-current interactions on neutrons to those on protons is measured to be 1.08±0.19.
No description provided.
No description provided.
No description provided.
Photoproduction of the cascade resonances has been investigated in the reactions $\gamma p \to K^+ K^+ (X)$ and $\gamma p \to K^+ K^+ \pi^- (X)$. The mass split of the $\Xi$ doublet is measured to be $5.4\pm 1.8$ MeV/c$^2$, consistent with existing measurements. The differential (total) cross sections for the $\Xi^{-}$ have been determined for photon beam energies from 2.75 to 3.85 (4.75) GeV, and are consistent with a possible production mechanism of $Y^*\to K^+\Xi^-$ through a $t$-channel process. The reaction $\gamma p \to K^+ K^+ \pi^-[\Xi^0]$ has also been investigated in search of excited cascade resonances. No significant signal of excited cascade states other than the $\Xi^-(1530)$ is observed. The cross section results of the $\Xi^-(1530)$ have also been obtained for photon beam energies from 3.35 to 4.75 GeV.
Differential cross section for XI- production as a function of the invariant mass of the XI- with either of the K+ mesons for incident photon energy 2.79 Gev.
Differential cross section for XI- production as a function of the invariant mass of the XI- with either of the K+ mesons for incident photon energy 2.89 Gev.
Differential cross section for XI- production as a function of the invariant mass of the XI- with either of the K+ mesons for incident photon energy 2.99 Gev.
We present the results on total channel cross-sections obtained in the Saclay 180 l HBC exposed to a separated K− beam at Nimrod. The cross-sections for each channel are given at 13 incident K− momenta between 1.26 and 1.84 GeV/c.
No description provided.
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