München 2019 – wissenschaftliches Programm
HK 54.2: Poster
Donnerstag, 21. März 2019, 16:30–19:00, Foyer Theresanium
Analysis of e+ e− → (γ/π+ π−) J/ψ π+ π− at BESIII — •Johannes Bloms, Nils Hüsken, Johannes Kellers, Alfons Khoukaz, Marcel Rump, and Frederik Weidner — Westfälische Wilhelms-Universität Münster, Münster, Germany
The region of the charmonium and charmonium-like spectrum around 3.9 GeV/c2 is a highly interesting one due to the observation of several unexpected states that do not fit the quark anti-quark assignment.
In 2006, the Belle Collaboration found a peak in the mass spectrum of DD mesons with M=3929±6 MeV/c2 and Γ = 29 ± 10 MeV called the X(3930) with JPC = 2++. Hence, this state was assigned to the χc2(2P) charmonium state.
In 2008, the BaBar Collaboration observed a resonance in the B→ J/ψ ω K decay, which was later reported by Belle in the γ γ → ω J/ψ process at M=3915±2± 3 MeV/c2 and Γ = 17±3± 10 MeV and finally confirmed by BaBar with JPC = 0++.
However, recent studies have altered the previous situation. The scalar X(3915) just might be the helicity-0 realisation of the tensor X(3930). The latter one also might be the s=2 partner of the X(3872) which is assumed to be a DD* bound state.
Since the X(3915) was only observed in the ω J/ψ decay channel so far, other channels have to be searched for. The current status of the analysis will be discussed. This work has been supported by the Deutsche Forschungsgemeinschaft (DFG) through the Research Training Group "GRK 2149: Strong and Weak Interactions - from Hadrons to Dark Matter".