Bonn 2010 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 31: QCD IV
T 31.7: Vortrag
Donnerstag, 18. März 2010, 18:15–18:30, HG X
Study of the glueball candidate f0(1710) with the ZEUS detector at HERA — •Vladyslav Libov — DESY, Hamburg, Germany
The production of the scalar resonance f0(1710), a candidate for the lightest glueball, is measured relatively to the tensor meson f′2(1525) in electron-proton collisions at HERA. The analysis is based on the data of the ZEUS experiment which were collected in 2004-2007. The dataset corresponds to approximately 380 pb−1 integrated luminosity.
The f0(1710) was reconstructed in the KS0KS0 decay channel. Peaks that could be attributed to the f2(1270), a2(1320), f′2(1525) mesons were also observed in the spectrum. Interference between tensor states was taken into account in the fit to the mass spectrum. Detailed studies show that a simple interference model which worked for γγ production with fixed relative amplitudes and phases is not valid. Instead, the interference parameters were determined from the fit. The observed cross-section ratio is
| σrel=0.7±0.1 |
(statistical error only). The result is close to the one obtained by L3 at LEP: σrel=0.67±0.18. This is in contradiction to the common assumption that the glueball production should be highly suppressed in γγ-collisions, thus expecting a larger ratio in ep collisions. Hence it is unlikely that the f0(1710) is a glueball.