Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant to Part-per-Million Precision

2010/10/05 by D. M. Webber, V. Tishchenko, Q. ~Peng +30 · 1 voice
Physics and Astronomy · #hep-ex #nucl-ex

paper · pdf · doi:10.1103/physrevlett.106.041803

published as Phys.Rev.Lett.106:041803,2011; Phys.Rev.Lett.106:079901,2011 · Accepted for publication in Phys. Rev. Lett

arxiv published 2010/10/05 · arxiv created 2010/12/06 · arxiv updated 2010/12/06

Abstract

We report a measurement of the positive muon lifetime to a precision of 1.0 parts per million (ppm); it is the most precise particle lifetime ever measured. The experiment used a time-structured, low-energy muon beam and a segmented plastic scintillator array to record more than 2 x 10¹² decays. Two different stopping target configurations were employed in independent data-taking periods. The combined results give tau_mu⁺(MuLan) = 2196980.3(2.2) ps, more than 15 times as precise as any previous experiment. The muon lifetime gives the most precise value for the Fermi constant: G_F(MuLan) = 1.1663788 (7) x 10^-5 GeV^-2 (0.6 ppm). It is also used to extract the mu^-p singlet capture rate, which determines the proton's weak induced pseudoscalar coupling g_P.

Discussions

• http://arxiv.org/abs/1010.0991 contains a precise measurement of the muon's lifetime, and indirectly of a parameter of the standard model [bsky, 0 points, 0 comments]

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