136 research outputs found
Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant to Part-per-Million Precision
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 10^{12} 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.Comment: Accepted for publication in Phys. Rev. Let
Improved Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant
The mean life of the positive muon has been measured to a precision of 11 ppm
using a low-energy, pulsed muon beam stopped in a ferromagnetic target, which
was surrounded by a scintillator detector array. The result, tau_mu =
2.197013(24) us, is in excellent agreement with the previous world average. The
new world average tau_mu = 2.197019(21) us determines the Fermi constant G_F =
1.166371(6) x 10^-5 GeV^-2 (5 ppm). Additionally, the precision measurement of
the positive muon lifetime is needed to determine the nucleon pseudoscalar
coupling g_P.Comment: As published version (PRL, July 2007
Assessing the Incidence and Wage Effects of Overeducation Among Italian Graduates Using a New Measure for Educational Requirements
Expression of COX-2, NF-κB-p65, NF-κB-p50 and IKKα in malignant and adjacent normal human colorectal tissue
Peer reviewedPublisher PD
Who is Overeducated and Why? Probit and Dynamic Mixed Multinomial Logit Analyses of Vertical Mismatch in East and West Germany
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