Muon decay: Measurement of the energy spectrum of theνeas a novel precision test for the standard model

1992 ◽  
Vol 69 (19) ◽  
pp. 2758-2760 ◽  
Author(s):  
Wulf Fetscher
Keyword(s):  
Energy Spectrum ◽  
Standard Model ◽  
Muon Decay ◽  
The Standard Model ◽  
Decay Measurement ◽  
Precision Test

scholarly journals The history of the muon (g-2) experiments

2019 ◽  
Author(s):  
B. Lee Roberts
Keyword(s):  
Standard Model ◽  
Quantum Electrodynamics ◽  
National Laboratory ◽  
New Physics ◽  
Brookhaven National Laboratory ◽  
Muon Decay ◽  
Higgs Bosons ◽  
The Standard Model ◽  
History Of ◽  
First Time

I discuss the history of the muon (g-2)(g−2) measurements, beginning with the Columbia-Nevis measurement that observed parity violation in muon decay, and also measured the muon gg-factor for the first time, finding g_\mu=2gμ=2. The theoretical (Standard Model) value contains contributions from quantum electrodynamics, the strong interaction through hadronic vacuum polarization and hadronic light-by-light loops, as well as the electroweak contributions from the WW, ZZ and Higgs bosons. The subsequent experiments, first at Nevis and then with increasing precision at CERN, measured the muon anomaly a_\mu = (g_\mu-2)/2aμ=(gμ−2)/2 down to a precision of 7.3 parts per million (ppm). The Brookhaven National Laboratory experiment E821 increased the precision to 0.54 ppm, and observed for the first time the electroweak contributions. Interestingly, the value of a_\muaμ measured at Brookhaven appears to be larger than the Standard Model value by greater than three standard deviations. A new experiment, Fermilab E989, aims to improve on the precision by a factor of four, to clarify whether this result is a harbinger of new physics entering through loops, or from some experimental, statistical or systematic issue.

scholarly journals Precision test of the standard model on the toponium resonance

1985 ◽  
Vol 163 (1-4) ◽  
pp. 247-249 ◽  
Author(s):  
B. Grzadkowski ◽  
P. Krawczyk ◽  
J.H. Kühn ◽  
R.G. Stuart
Keyword(s):  
Standard Model ◽  
The Standard Model ◽  
Precision Test

scholarly journals Muon decay and physics beyond the standard model

2001 ◽  
Vol 73 (1) ◽  
pp. 151-202 ◽  
Author(s):  
Yoshitaka Kuno ◽  
Yasuhiro Okada
Keyword(s):  
Standard Model ◽  
Muon Decay ◽  
Beyond The Standard Model ◽  
The Standard Model

scholarly journals Asymmetry Measurements at LEP/SLC Revisited

1997 ◽  
Vol 12 (33) ◽  
pp. 2535-2541 ◽  
Author(s):  
Tariq Aziz
Keyword(s):  
Standard Model ◽  
Excellent Agreement ◽  
Weak Mixing Angle ◽  
Weak Mixing ◽  
Mixing Angle ◽  
Class A ◽  
The Standard Model ◽  
Class B ◽  
Precision Test

We examine the fermion asymmetry measurements at LEP and SLC leading to effective weak mixing angle, sin 2θ eff . We notice very interesting regularity in these measurements. All asymmetry measurements fall into two classes. Class A measurements where hadronisation effects are not relevant for the final result and class B measurements where hadronisation effects cannot be avoided and can only be corrected with whatever understanding of these phenomena we have. In each of these classes there is excellent agreement between LEP and SLC results. However the two classes are distinctly apart by more than 3σ. We suggest that for precision test of the Standard Model the class A measurements should be preferred.

scholarly journals Coherent Elastic Neutrino-Nucleus Scattering as a Precision Test for the Standard Model and Beyond: The COHERENT Proposal Case

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
O. G. Miranda ◽  
G. Sanchez Garcia ◽  
O. Sanders
Keyword(s):  
Standard Model ◽  
Sterile Neutrino ◽  
New Physics ◽  
Recent Measurement ◽  
Future Perspectives ◽  
Weak Mixing Angle ◽  
Mixing Angle ◽  
The Standard Model ◽  
Nucleus Scattering ◽  
Precision Test

Several experimental proposals expect to confirm the recent measurement of the coherent elastic neutrino-nucleus scattering (CEvNS). Motivated in particular by the next generation experiments of the COHERENT collaboration, we study their sensitivity to different tests of the Standard Model and beyond. We analyze the resolution that can be achieved by each future proposed detector in the measurement of the weak mixing angle; we also perform a similar analysis in the context of Nonstandard Interaction (NSI) and in the case of oscillations into a sterile neutrino state. We show that future perspectives are interesting for these types of new physics searches.

Calculation of the μ → eγ muon decay in the small-neutrino-mass limit

2014 ◽  
Vol 92 (12) ◽  
pp. 1587-1591
Author(s):  
Jian-Ping Bu ◽  
Yu-Min Liang ◽  
Xue-Wen Gu
Keyword(s):  
Standard Model ◽  
Neutrino Mass ◽  
Muon Decay ◽  
Mass Limit ◽  
The Standard Model ◽  
Accidental Symmetry ◽  
Lepton Flavour

The μ → eγ decay is strictly forbidden in the Standard Model, where the lepton flavour is conserved as an accidental symmetry, but in extensions of the Standard Model the lepton flavour is generally no longer conserved, so that decay can take place. In this paper we calculate the amplitude, in an Rξ gauge, of muon decay in the small-neutrino-mass limit. The result, in which ξ-dependence is cancelled, is different from the amplitude and the technical points obtained in previous work.

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