Darmstadt 2016 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 64: Hadron Structure and Spectroscopy XI

HK 64.1: Gruppenbericht

Freitag, 18. März 2016, 14:00–14:30, S1/01 A5

Status of d^*(2380) and Search for an Isospin I = 3 Dibaryon Resonance^*. — •Heinz Clement¹, Mikhail Bashkanov², and Tatiana Skorodko¹ for the WASA-at-COSY collaboration — ¹Physikalisches Institut der Universität Tübingen — ²School of Physics and Astronomy, University of Edinburgh, UK

For the meanwhile established dibaryon resonance d^*(2380) with I(J^P) = 0(3⁺) all decay branchings into NN and NNππ channels have been determined. A principially possible, though unlikely decay into the isoscalar NNπ channel is under investigation – see separate contribution. The total decay width as well as the extracted branching ratios bear important information about the internal structure of the dibaryon. They agree with a subthreshold ΔΔ system as asymtotic two-hadron configuration in the intermediate state and discriminate against other recently discussed decay scenarios like, e.g. via the NΔ threshold state D₁₂(2144).

The experimental results are compared with various theoretical calculations in the framework of Faddeev or quark model treatments. The possible role of hidden color is discussed.

Many of these theoretical studies predict also another, truly exotic state with mirrored quantum numbers I(J^P) = 3(0⁺), i.e. decoupled from the NN system and consisting of just six up-quarks in its I_z = +3 state. Such a state may be searched for in four-pion production. The status of this search by use of WASA data on the pp → ppπ⁺π⁺π⁻π⁻ reaction will be reported.

^*supported by DFG (CL 214/3-1) and STFC (ST/L00478X/1)