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a0+(980)-resonance production in the reaction pp -> dpi+eta close to the K(bar(K)) threshold

P. Fedorets·M. Buescher·V. P. Chernyshev·S. Dymov·V. Yu. Grishina·C. Hanhart·M. Hartmann·V. Hejny·V. Kleber·H. R. Koch·L. A. Kondratyuk·V. Koptev·A. E. Kudryavtsev·P. Kulessa·S. Merzliakov·S. Mikirtychiants·M. Nekipelov·H. Ohm·R. Schleichert·H. Stroeher·V. E. Tarasov·K. -H. Watzlawik·I. Zychor
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Abstract

The reaction pp -> dpi+eta has been measured at a beam energy of T=2.65 GeV (p=3.46 GeV/c) using the ANKE spectrometer at COSY-Juelich. The missing mass distribution of the detected dpi+ pairs exhibits a peak around the eta mass on top of a strong background of multi-pion pp -> dpi+(n(pi)) events. The differential cross section d^4(sigma)/d(Omega_d)d(Omega_pi+)d(p_d)d(p_pi+) for the reaction pp -> dpi+eta has been determined model independently for two regions of phase space. Employing a dynamical model for the a0+ production allows one then to deduce a total cross section of sigma(pp -> da0+ -> dpi+eta)=(1.1 +/- 0.3_(stat) +/- 0.7_(syst)) microbarn for the production of pi+eta via the scalar a0+(980) resonance and sigma(pp -> dpi+eta) = (3.5 +/- 0.3_(stat) +/- 1.0_(syst)) microbarn for the non-resonant production. Using the same model as for the interpretation of recent results from ANKE for the reaction pp -> dK+(bar(K0)), the ratio of the total cross sections is sigma(pp -> d(K+(bar(K0)))_(L=0))/sigma(pp -> da0+ -> dpi+eta) = 0.029 +/- 0.008_(stat) +/- 0.009_(syst), which is in agreement with branching ratios in the literature.

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P. Fedorets, M. Buescher, V. P. Chernyshev, S. Dymov, V. Yu. Grishina, C. Hanhart, M. Hartmann, V. Hejny, V. Kleber, H. R. Koch, L. A. Kondratyuk, V. Koptev, A. E. Kudryavtsev, P. Kulessa, S. Merzliakov, S. Mikirtychiants, M. Nekipelov, H. Ohm, R. Schleichert, H. Stroeher, V. E. Tarasov, K. -H. Watzlawik, I. Zychor. 2005-01-28. a0+(980)-resonance production in the reaction pp -> dpi+eta close to the K(bar(K)) threshold. https://doi.org/10.1134/s1063778806020153

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