TWIST Technote 93

Effect of proton beam variations on TWIST results

Glen Marshall, 12 May 2004

The purpose of this note is to record and assess some information which can be used to establish the systematic uncertainty in TWIST results due to variations in the proton beam position. When the proton beam position on the 1AT1 production target changes, the effective source of surface muons may also change. This in turn affects the position and shape of the muon beam at the end of M13, and in principle the measured values of Michel parameters could also change. The uncertainty associated with this potential change is estimated to be small compared with $10^{-3}$, but to measure it more carefully requires at least one simulation result which we don't yet have.


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