Browsing by All Authors "Babacan, H."

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    Associative photoproduction of roper resonance with vector mesons
    (Turkish Atomic Energy Authority, 2000-10) Babacan, T.; Babacan, H.; Gökalp, A.; Yılmaz, O.; 8495; Bölüm Yok
    We examine the associative photoproduction of Roper resonance with vector mesons, γ +N—>N* ( 1440)+V. in the near threshold region by using the analogy with the processes of “elastic” vector meson photoproduction, γ +N—>N+V. Different production mechanisms are suggested. In addition to standart α- and π-exchanges in the t-channel, the baryonic exchanges in the s- and u-channel are taken into account as well. We calculate the differential cross-section and beam asymmetry on proton and neutron targets for the reaction γ+N—>N*(1440)+ω. All calculations are performed at Eγ,= 2.5 GeV. The recent study [1] on the associative photoproduction o f Roper resonance with vector mesons, γ+N —>N*(1440)+V, in the near threshold region indicates the importance of the pseudoscalar (π) exchange for t-channel in associative ω-meson photoproduction but it does not give a clear information about the relative role of different possible threshold mechanisms on the production o f N*(1440). Therefore, in additon to standart G- and δ-exchanges in the t-channel, we consider the baryonic resonances in the s- and u-channel . For t-channel, the pseudoscalar (π) and scalar exchanges ( δ ), Fig. 1(a), are considered The pseudoscalar exchange amplitude can be obtained from the Lagrangian,....
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    Photoproduction of vector mesons on nucleons: relative role of possible threshold mechanisms
    (Turkish Atomic Energy Authority, 2000-10) Babacan, T.; Babacan, H.; Gökalp, A.; Yılmaz, O.; 8495; Bölüm Yok
    We analyze the photoproduction of co-meson on nucleons in order to understand the relative role of different possible threshold mechanisms. Therefore, we propose a set o f models with the different contributions of the exchange mechanisms which are equally good for the differential cross-section of γ+p→p+ω: pseudoscalar (π) and scalar exchanges (δ) in t-channel and the s+u nucleon term. We fit our model results to the experimental data about the differential crosssection in the energy ranges 1.4 GeV < E., <1.8 GeV and 1.8 GeV< E., < 2.5 GeV, simultaneously, and obtain some sets for the coupling constants, gTωNN an gVωNN. All calculations are done at Eγ = 1.6 GeV ( for the energy range 1.4 GeV < E., < 1.8 GeV ) , and Eγ = 2.2 GeV (for the energy range 1.8 GeV< Eγ< 2.5 GeV). We found some sensitivity of the differential cross-section on neutron targets and the beam asymmetry on proton and neutron targets as well, to the variations of the different models which are equivalently good for the differential cross-section on proton target.