π -4 He interactions at T π = 106 MeV have been studied by means of a self-shunted streamer chamber filled with helium at atmospheric pressure. This technique allowed reconstruction of the complete kinematics of the nuclear events under analysis, since tracks of slow p, α, tritium and 3 He are readily measurable. The study revealed that the 4 He nucleus behaves as a Planck radiator, emitting a T = 14 MeV Planck-like spectrum of high energy γ s, when hit by a π beam of T π = 106 MeV. A resonant behaviour in the π -n invariant mass spectrum has been observed, with Mπ -n = 1160 MeV and Γ = 20 MeV in the π -4 He neutron knockout reaction: we consider this to be the first experimental evidence for the existence of the ∆ -. The observed mass shift and width narrowing are compatible with the activation of an isobaric collective resonance in the 4 He nucleus. The collaboration has also observed a resonant behaviour in the π -pp invariant mass spectrum in the π + ( 105 Ag, 103 Ag)π -pp double-charge-exchange reaction, on nuclear photoemulsion, compatible with the activation of the J P = 0 -d dibaryonic resonance with a strong p-p final state interaction. A new direct measured upper limit for the ν µ mass has been derived by measuring a complete decay π -µ-e event recorded at the CERN PS179 experiment ( p20 Ne scattering): at a 90% confidence level, Mµ ν ≤ 2.2 MeV.