On the precise determination of the Fermi coupling constant from the muon lifetime

Ritbergen, T. van; Stuart, Robin G.

doi:10.1016/s0550-3213(99)00572-6

Cited by 142 publications

(152 citation statements)

References 67 publications

(84 reference statements)

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“…We extract G µ from τ µ via 27) where F (ρ) = 1 − 8ρ + 8ρ 3 − ρ 4 − 12ρ 2 ln ρ = 0.9981295 (for ρ = m 2 e /m 2 µ ) is the phase space factor and ∆q = ∆q (1) +∆q (2) = (−4.234+0.036)×10 −3 are the QED corrections computed at one [102] and two loops [103]. From the measurement τ µ = (2196980.3 ± 2.2) ps [100] we find G µ = 1.1663781(6) 10 −5 / GeV 2 .…”

Section: Two-loop Correction To the Higgs Quartic Couplingmentioning

confidence: 99%

Investigating the near-criticality of the Higgs boson

Buttazzo

Degrassi

Giardino

et al. 2013

J. High Energ. Phys.

1,145

1,803

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We extract from data the parameters of the Higgs potential, the top Yukawa coupling and the electroweak gauge couplings with full 2-loop NNLO precision, and we extrapolate the SM parameters up to large energies with full 3-loop NNLO RGE precision. Then we study the phase diagram of the Standard Model in terms of high-energy parameters, finding that the measured Higgs mass roughly corresponds to the minimum values of the Higgs quartic and top Yukawa and the maximum value of the gauge couplings allowed by vacuum metastability. We discuss various theoretical interpretations of the near-criticality of the Higgs mass.

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Section: Two-loop Correction To the Higgs Quartic Couplingmentioning

confidence: 99%

Investigating the near-criticality of the Higgs boson

Buttazzo

Degrassi

Giardino

et al. 2013

J. High Energ. Phys.

1,145

1,803

View full text Add to dashboard Cite

show abstract

“…where F (ρ) = 1 − 8ρ + 8ρ 3 − ρ 4 − 12ρ 2 ln ρ = 0.9981295 (for ρ = m 2 e /m 2 µ ) is the phase space factor and ∆q = ∆q (1) + ∆q (2) = (−4.234 + 0.036) × 10 −3 are the QED corrections computed at one [55] and two loops [56]. The calculation of ∆r W requires the subtraction of the QED corrections, matching the result in the SM with that in the Fermi theory…”

Section: ∆R Wmentioning

confidence: 99%

The m W − m Z interdependence in the Standard Model: a new scrutiny

Degrassi

Gambino

Giardino

2015

J. High Energ. Phys.

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Abstract:The m W − m Z interdependence in the Standard Model is studied in the M S scheme at the two-loop level, including the known higher-order contributions. The relevant radiative parameters, ∆α(µ), ∆r W ,ρ are computed at O(α 2 ) taking into account higherorder QCD corrections and the resummation of the reducible contributions. We obtain m W = 80.357 ± 0.009 ± 0.003 GeV where the errors refer to the parametric and theoretical uncertainties, respectively. A comparison with the known result in the On-Shell scheme gives a difference of ≈ 6 MeV. As a byproduct of our calculation we also obtain the M S electromagnetic coupling and the weak mixing angle at the top mass scale,α(M t ) = (127.73) −1 ± 0.0000003 and sin 2θ W (M t ) = 0.23462 ± 0.00012.

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“…Prior to 1999, the limitation on the precision of G F was dominated by the uncertainty on ∆q. Van Ritbergen and Stuart were the first to compute the secondorder QED radiative corrections in the massless electron limit, reducing the theoretical uncertainty to below 0.3 ppm [3], and well below the then-current experimental uncertainty. This development motivated a new generation of precision muon lifetime measurements, MuLan [4] and FAST [5].…”

mentioning

confidence: 99%

“…This development motivated a new generation of precision muon lifetime measurements, MuLan [4] and FAST [5]. More recently, Pak and Czarnecki extended the result in [3] to finite electron mass, which shifts the predicted decay rate 1/τ µ by -0.43 ppm; alternatively, it decreases G F by 0.21 ppm [6].…”

mentioning

confidence: 99%

Publisher’s Note: Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant to Part-per-Million Precision [Phys. Rev. Lett.106, 041803 (2011)]

Webber

Tishchenko²,

Peng³

et al. 2011

Phys. Rev. Lett.

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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 × 10 12 decays. Two different stopping target configurations were employed in independent data-taking periods. The combined results give τ µ + (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: GF (MuLan) = 1.1663788(7) × 10 −5 GeV −2 (0.6 ppm). It is also used to extract the µ − p singlet capture rate, which determines the proton's weak induced pseudoscalar coupling g P .A measurement of the positive muon lifetime, τ µ + , to high precision determines the Fermi constant, G F , according to the relationHere, ∆q represents well-known phase space and both QED and hadronic radiative corrections [1], and we assume that G F is universal for weak interactions. Strictly speaking, τ µ + determines a muon-decay-specific coupling, denoted G µ , which could be compared to other G F determinations as a test of the standard model [2]. Prior to 1999, the limitation on the precision of G F was dominated by the uncertainty on ∆q. Van Ritbergen and Stuart were the first to compute the secondorder QED radiative corrections in the massless electron limit, reducing the theoretical uncertainty to below 0.3 ppm [3], and well below the then-current experimental uncertainty. This development motivated a new generation of precision muon lifetime measurements, MuLan [4] and FAST [5]. More recently, Pak and Czarnecki extended the result in [3] to finite electron mass, which shifts the predicted decay rate 1/τ µ by -0.43 ppm; alternatively, it decreases G F by 0.21 ppm [6].In Ref.[4], we reported an 11 ppm measurement of τ µ + based on a relatively short commissioning run. This Letter reports the results from a 100 times larger data set, accumulated using the final setup of the experiment.The experiment is designed to stop muons in a target during a beam-on accumulation interval and measure the decay positrons-primarily from the µ + → e + ν eνµ decay mode-during a beam-off measurement period. The two running periods, R06 and R07, used different targets. More than 10 12 decays were recorded in each period.The experiment used the πE3 beamline at the Paul Scherrer Institute (PSI). During the run, positive muons from at-rest pion decay near the surface of the production target are directed to the experiment through two opposing vertical dipole magnets and a series of 15 magnetic quadrupole lenses. A velocity-selecting E × B separator is tuned to pass muons and reject positrons. A special feature of the beamline is a custom, 60-ns switching, 25-kV kicker [8]. When energized, the electric field across the 120-mm vertical gap and 1500-mm length displaces the muon beam by 46 mm at the exit and deflects it by 45 mrad onto a downstream collimator. The muon flux of ∼ 1...

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On the precise determination of the Fermi coupling constant from the muon lifetime

Cited by 142 publications

References 67 publications

Investigating the near-criticality of the Higgs boson

Investigating the near-criticality of the Higgs boson

The m W − m Z interdependence in the Standard Model: a new scrutiny

Publisher’s Note: Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant to Part-per-Million Precision [Phys. Rev. Lett.106, 041803 (2011)]

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