A. Pricking

Double-pionic fusion of nuclear systems and the "ABC" effect: approaching a puzzle by exclusive and kinematically complete measurements.

The ABC effect-a puzzling low-mass enhancement in the pipi invariant mass spectrum, first observed by Abashian, Booth, and Crowe-is well known from inclusive measurements of two-pion production in nuclear fusion reactions. Here we report on the first exclusive and kinematically complete measurements of the most basic double-pionic fusion reaction pn-->dpi;{0}pi;{0} at beam energies of 1.03 and 1.35 GeV. The measurements, which have been carried out at CELSIUS-WASA, reveal the ABC effect to be a (pipi)_{I=L=0} channel phenomenon associated with both a resonancelike energy dependence in the integral cross section and the formation of a DeltaDelta system in the intermediate state. A corresponding simple s-channel resonance ansatz provides a surprisingly good description of the data.

Evidence for a New Resonance from Polarized Neutron-Proton Scattering

Exclusive and kinematically complete high-statistics measurements of quasifree polarized (n) over right arrowp scattering have been performed in the energy region of the narrow resonancelike struct ...

Isospin decomposition of the basic double-pionic fusion in the region of the ABC effect

Exclusive and kinematically complete high-statistics measurements of the basic double-pionic fusion reactions pn -> d pi(0)pi(0), pn -> d pi(+)pi(-) and pp -> d pi(+)pi(0) have been carrie ...

Neutron-proton scattering in the context of the d*(2380) resonance

New data on quasifree polarized neutron-proton scattering in the region of the recently observed d* resonance structure are obtained by exclusive and kinematically complete high-statistics measurem ...

Measurement of the pn -> pp pi(0)pi(-) reaction in search for the recently observed resonance structure in d pi(0)pi(0) and d pi(+)pi(-) systems

Exclusive measurements of the quasi-free

Search for eta-mesic He-4 with the WASA-at-COSY detector

pn to pppi^0pi^-

Search for a dark photon in the pi(0) -> e(+)e(-)gamma decay

reaction have been performed by means of

Measurement of the eta -> pi(+)pi(-)pi(0) Dalitz plot distribution

pd

Single- and double-pion production in nucleon collisions on the nucleon and on nuclei—the ABC effect and its origin in a dibaryonic resonance

collisions at

Investigation of the dd -> (3)Hen pi(0) reaction with the FZ Julich WASA-at-COSY facility

T_p