Physics of elementary particles
In the field of Elementary Particles the Group of Brescia has produced important contributions within the experiment PS201 OBELIX, an international collaboration formed in 1985 in order to operate at L.E.A.R. of the CERN, with the aim of characterizing the mesonic systems with light quarks or with gluons, formed especially by the annihilation of the antiproton at rest on hydrogen, or of the antineutron at low kinetic energies again on hydrogen.
The conclusive article published twenty years after the beginning of the Collaboration underlines how the technique of the various densities used in order to stop antiprotons in hydrogen was decisive to have the control of the partial waves, that contribute to the formation of mesonic states in the pp annihilation at rest. This work played an important role in the phenomenological description within the QCD (Quantum Chromo Dynamics) of the decays of the produced mesons. Tens of articles have illustrated the information obtained from the analysis of the several channels of NN annihilation studied. Below we mention the last and conclusive articles.
- M. Bargiotti et al., Coupled channel analysis of π+π-π0, K+K-π0 and K±K0sπ±
from pp annihilation at rest in hydrogen targets at three densities Eur. Phys. J. C 26, 371 (2003)
- M. Bargiotti et al., Dynamical selection rules from pp annihilation at rest in three meson final states Eur. Phys. J. C 35, 177 (2004)
PS 201 – APPARATO OBELIX