Search for He-eta bound states with the WASA-at-COSY facility

Abstract

The existence of eta-mesic nuclei in which the eta meson is bound in a nucleus by means of the strong interaction was postulated already in 1986, albeit not yet confirmed it by experiment. The discovery of this new kind of an exotic nuclear matter would be very important as it might allow for a better understanding of the eta meson structure and its interaction with nucleons. The search for eta-mesic helium 4He-eta is carried out with high statistics and high acceptance with the WASA detector, installed at the cooler synchrotron COSY of the Research Center Juelich. The search is conducted via the measurement of the excitation function for selected decay channels of the 4He-eta system. In the experiment, performed in November 2010, two reactions dd->(4He-eta)bs ->3He p pi- and dd->(4He-eta)bs ->3He p pi0 were measured with a beam momentum ramped from 2.127GeV/c to 2.422GeV/c. The report includes the description of the experimental method and status of the measurement.

Presented at the Erice School on Nuclear Physics 2011. 5 pages, 3 figures

References in corpus (8)

• Photoproduction of eta-mesic 3He
• Precision study of the eta-3He system using the d+p->3He+eta reaction
• Measurement of the dp -->3He eta reaction near threshold
• Eta bound states in nuclei: a probe of flavour-singlet dynamics
• Is there an eta-3He quasi--bound state ?
• Search for the 3He-eta bound state at COSY-11
• Study of the 3He-eta system in d-p collisions
• Eta and eta' mesons production at COSY-11

Cited by in corpus (11)

• Search for the eta-mesic 4He with WASA-at-COSY detector
• $\eta$-nucleus interaction from the $d+d$ reaction around the $\eta$ production threshold
• Upper limits for the production of the eta-mesic Helium in the dd ->3Henpi0 and dd -> 3Heppi- reactions
• Few-body aspects of the near threshold pseudoscalar meson production
• Study of the N N eta' production with COSY-11
• Search for the manifestation of the mesic-nuclei on the dd-->3HeNpi excitation function measured with WASA-at-COSY
• Structure of double pionic atoms
• Luminosity determination for the deutron-deutron reactions using free and quasi-free reactions with WASA-at-COSY detector
• Search for the eta-mesic Helium bound state with the WASA-at-COSY facility
• Search for the 4He-eta bound state in dd->(4He-eta)_{bound}->3He n pi0 and dd->(4He-eta)_{bound}->3He p pi- reactions with the WASA-at-COSY facility
• Close to threshold eta' meson production in proton-proton collisions at COSY-11