The 17th APPEAL Seminar
APPEAL 17-06
Date and Time: 13:30 - 14:30 November 7th, 2006
Place: Seminar room B, Main building 3F, JASRI/SPring-8
Speaker: Dr Y. Maeda, RCNP Osaka Univ.
Title: Near threshold production of Phi-meson in pN collisions at COSY-ANKE facility
Abstract: At the ANKE facility of COSY Juelich, the reactions pp->ppPhi and pn->dPhi have been measured by detecting K+K- pairs from the Phi-meson decay in coincidence with the fast proton and deuteron, respectively. Data for the total cross section in pp-channel have been obtained at the excess energies of 19-76 MeV, being new data points below the energy of DISTO measurement. The reaction pn->dPhi has been measured using a deuterium target at a fixed beam energy 2.65 GeV.
First data for the total cross section as well as the energy dependence of differential cross section has been obtained at the excess energies range from 0 to 80 MeV making use the Fermi motion of the target neutron.
Production on the neutron is found to be stronger than on the proton but not by as much as for the Eta-meson. The Phi polarization, as measured through its K+K- decay, shows the early onset ofp-waves on the neutron, whereas s-wave contribution dominate the production at 19 MeV on proton target. The new Phi data combined with SPES-III, TOF-COSY and ANKE results on Omega-meson production provide additionally the total cross section ratios of Phi/Omega production in pp- and pn-channel.
The ratio is found to be similar for both channel, i.e. of about eight times larger than the ratio based on OZI rule (R(OZI) = 0.0042), indicating that in the Phi/Omega cross section ratio for nucleon-nucleon collisions there is no strong dependence on the initial spin state of entrance nucleons, i.e. the spin-triplet state and spin-singlet state in pp- and pn-channel, respectively.
The total cross sections as well as the differential distributions for both reactions will be also presented and discussed.
The recent results from ANKE facility will be also shown in this talk.
Contact: Prof. Hiro Ejiri. SPring-8/IIAS/RCNP