A search for the Z(3930) resonance in gamma gamma production of the D (D) over bar system has been performed using a data sample corresponding to an integrated luminosity of 384 fb(-1) recorded by the BABAR experiment at the PEP-II asymmetric-energy electron-positron collider. The D (D) over bar invariant mass distribution shows clear evidence of the Z(3930) state with a significance of 5.8 sigma. We determine mass and width values of (3926.7 +/- 2.7 +/- 1.1) MeV/c(2) and (21.3 +/- 6.8 +/- 3.6) MeV, respectively. A decay angular analysis provides evidence that the Z(3930) is a tensor state with positive parity and C parity (J(PC) = 2(++)); therefore we identify the Z(3930) state as the chi(c2)(2P) meson. The value of the partial width Gamma(gamma gamma) x B(Z(3930) -> D (D) over bar) is found to be (0.24 +/- 0.05 +/- 0.04) keV.
Titolo: | Observation of the chi(c2)(2P) meson in the reaction gamma gamma -> D(D)over-bar at BABAR RID C-5223-2009 | |
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Data di pubblicazione: | 2010 | |
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Digital Object Identifier (DOI): | http://dx.doi.org/10.1103/PhysRevD.81.092003 | |
Handle: | http://hdl.handle.net/11384/5301 | |
Appare nelle tipologie: | 1.1 Articolo in rivista |