Near-Threshold η Meson Production in Proton–Proton Collisions
نویسندگان
چکیده
The production of η mesons has been measured in the proton-proton interaction close to the reaction threshold using the COSY-11 internal facility at the cooler synchrotron COSY. Total cross sections were determined for eight different excess energies (ǫ) in the range from ǫ = 0.5 MeV to ǫ = 5.4 MeV. The energy dependence of the total cross section is well described by the available phase–space volume weighted by FSI factors for the proton–proton and proton–η pairs. PACS: 13.60.Le, 13.75.-n, 13.85.Lg, 25.40.-h, 29.20.Dh Typeset using REVTEX 1
منابع مشابه
Instantons and η Meson Production near threshold in NN collisions
An enhancement for the η production in proton-neutron collisions as compared with that in proton-proton scattering has been recently observed. We present a calculation for the production cross section, in proton-neutron collisions near threshold, within instanton model for the QCD vacuum and show that a specific flavor dependent nonperturbative quark-gluon interaction related to instantons is a...
متن کامل60 40 43 v 1 2 5 A pr 1 99 6 Near threshold η production in proton - proton collisions
The total cross section for the near threshold η production in proton-proton collisions has been investigated with the assumption that the production mechanism is due to the emission of a meson x(π, η, σ) from one of the nucleons followed by a xN → ηN transition on the second one. The xN → ηN amplitudes are generated from the unitary multi-channel multi-resonance model which has recently been c...
متن کاملNear threshold production of the pseudoscalar mesons at the COSY-11 facility
We summarise measurements of the COSY-11 collaboration concerning the excitation functions of the near threshold pseudoscalar meson production in the proton-proton interaction. The results are discussed in the context of the meson-nucleon and hyperon-nucleon interactions. We conclude that the η-proton interaction is significantly stronger than the η′-proton interaction. Similarly, we found that...
متن کاملEffective Field Theory Approaches to Pion Production in Proton–proton Collisions
Over the last years, very precise data on pion, η and η meson production in proton-proton collisions in the threshold region have been obtained at IUCF, CELSIUS and COSY (for a review, see the talk by H.O. Meyer ). The basic process is pp → pNM , where N denotes the nucleon and M a pseudoscalar meson, in our case the π, π, η or the η. At the respective threshold, the produced meson is soft, i.e...
متن کاملFew-Body Aspects of the Near Threshold Pseudoscalar Meson Production
During the last decade large samples of data have been collected on the production of the groundstate pseudoscalar mesons in collisions of proton or deuteron beam with hydrogen or deuterium target. These measurements have been performed in the vicinity of the kinematical threshold for meson production where only a few partial waves in both initial and final state are expected to contribute to t...
متن کامل