Eur. Phys. J. A (2007) 34: 255-269
https://doi.org/10.1140/epja/i2007-10514-3

Regular Article - Experimental Physics

Two-prong πHe interactions at 106 MeV

¹ Joint Institute for Nuclear Research, JINR, Dubna, Russia
² Dipartimento di Fisica Generale “A. Avogadro”, Università di Torino, INFN Sezione di Torino, I-10125, Torino, Italy
³ Gruppo collegato di Alessandria, Università del Piemonte Orientale and INFN, Alessandria, Italy
⁴ Gruppo collegato di Brescia, Università di Brescia and INFN, Brescia, Italy
⁵ Alikhanov Institute for Theoretical and Experimental Physics, ITEP, Moscow, Russia
⁶ Centro Studi e Ricerche “Enrico Fermi”, Roma, Italy

Received: 18 April 2007
Accepted: 30 November 2007
Published online: 7 January 2008

Abstract

π^-4He interactions at 106MeV, with two secondary charged particles in the final state, have been studied using a self-shunted streamer chamber in a 0.65T magnetic field and equipped with two CCD videocameras for obtaining digitized stereo-images of nuclear events occurring within the fiducial volume of the streamer chamber. Branching ratios for the various interaction channels are deduced. Evidence is presented for a reaction channel involving a γ produced in the final state, as well as for the first observation of direct Δ^- -resonance production. Cross-section distributions for the elastic and quasi-elastic interaction channels are also reported.