Precise treatment of pion decays in flight in the PEN experiment
Abstract
The PEN experiment at Paul Scherrer Institute aims to measure the leptonic decay &+circ;->e^+ν(γ) branching ratio with 5.10-4 relative uncertainty. The shower leakage for 70,eV monoenergetic positrons in the CsI electromagnetic calorimeter is of the order of 2,% for ECALO<50,MeV and presents an important systematic uncertainty. We discuss the ways the low energy e^+ tail can be extracted from the measured data and distinguished from π->μ->e decays in flight (DIF) that results in a positron in the same 0-50,MeV range. We compare the measured e^+ energy tail spectra and DIF with realistic GEANT4 simulations done with the photonuclear processes included.
- Publication:
-
APS Division of Nuclear Physics Meeting Abstracts
- Pub Date:
- October 2012
- Bibcode:
- 2012APS..DNP.KE003F