Speaker
Dr
Eusebio Sanchez
(CIEMAT - Madrid)
Description
The Fibre Active Scintillator Target (FAST) experiment at the Paul Scherrer Institute is designed to measure the $\mu^+$ lifetime to 4 ps precision and thereby to determine the Fermi coupling constant, $G_F$, to 1 ppm. In FAST, a $\pi^+$ beam is stopped inside a highly granular target which images the entire $\pi^+\rightarrow \mu^+\rightarrow e^+$ decay chain. To achieve the high statistics required, the detector has a modular structure which allows simultaneous mesurements of several decay chains. The concept of the FAST detector provides strong intrinsic suppression of potential systematic effects and allows operation at high beam rates. In 2008 and 2009, FAST collected a total statistics of $4.2\times10^{11}$ identified $\mu^+$ decays, allowing a statistical precision of 1.2 ppm on $G_F$. The analysis of these
data will be presented.
Primary author
Dr
Jorge Casaus
(CIEMAT - Madrid)
Co-authors
Dr
Artur Barczyk
(CERN)
Dr
Carlos Mana
(CIEMAT - Madrid)
Dr
Carlos Willmott
(CIEMAT - Madrid)
Dr
Chiara Casella
(ETHZ)
Dr
Claude Petitjean
(PSI)
Dr
Eusebio Sanchez
(CIEMAT - Madrid)
Mr
Gaetano Barone
(Université de Genève)
Mr
Gustavo Martinez
(CIEMAT - Madrid)
Dr
Jasper Kirkby
(CERN)
Dr
Javier Berdugo
(CIEMAT - Madrid)
Mr
Jesus Marin
(CIEMAT - Madrid)
Dr
Konrad Deiters
(PSI)
Dr
Luca Malgeri
(CERN)
Prof.
Martin Pohl
(Université de Genève)
Mr
Peter Dick
(PSI)
Mr
Samuel De Laere
(Université de Genève)
