The PIENU experiment, a sensitive probe for new physics with pion decays (Iván Ortega, ICN-UNAM)

Tuesday 20 Aug 2024, 11:00 → 13:00 America/Mexico_City

The PIENU experiment at the TRIUMF laboratory, Canada, aims to provide a high precision measurement of the pion decay branching ratio Rπ = Γ(π+ → e+νe(γ))/Γ(π+ → µ+νµ(γ)), calculated within the standard model as R^{SM}_π = (1.2352 ± 0.0002) × 10^{−4} with a precision of 0.016%. Different scenarios for physics BSM such as the violation of lepton universality, or new pseudoscalar interactions have an impact on Rπ . By measuring Rπ with a precision comparable to the SM prediction, the sensitive structure of the weak interaction can be tested.
Between 2009 and 2012, PIENU accumulated 6.5 million π+ → e+νe decays, operating at the M13 beamline at TRIUMF. The analysis of a subset of the 2010 data with 400 thousand events was published in 2015 in agreement with the SM with a precision of 0.24%. The inclusion of additional 5.5 million events to the analysis can potentially increase the precision up to 0.1%. In this presentation, the progress of the PIENU analysis will be discussed.