Design of an experiment for the measurement of Pontecorvo reactions

by Luca Venturelli (Universita di Brescia (IT))

Wednesday 8 Nov 2023, 17:00 → 18:00 Europe/Vienna

Stefan Meyer Institute

Location:
PSK, Georg-Coch-Platz 2, Seminar room 4A.2, 4th floor (signposts will guide the way from the main entrance)

Abstract:
The Pontecorvo reactions are rare antiproton annihilation processes forbidden on a free nucleon but allowed on nucleons bound in nuclei.
Some measurements were performed in the past at CERN’S LEAR by using deuterium target.
Recently, it has been proposed [1] that the exploration of Pontecorvo reactions could be extended to CERN's ELENA-AD ring. The ASACUSA collaboration could undertake this study by utilizing a continuous beam of antiprotons, which would be directed towards targets consisting of 3 nucleons, such as ³He or ³H.
The measurement of the rates of the processes

pbar 3He --> n p (1)
pbar 3He --> n n (1)

it would allow distinguishing between different theoretical models whose predictions differ by 1-2 orders of magnitude.
We present a preliminary design of a simple measurement apparatus that utilizes plastic scintillators and degrader layers. The results of the Monte Carlo simulations with GEANT4 on the performance of the apparatus are also shown, both in terms of efficiency of the measurement of the signals (1) and (2), and in terms of background rejection coming from typical antiproton annihilations on the target.

[1] C. Amsler, Nucleon-antinucleon annihilation at LEAR, arXiv:1908.08455