Fermi Constant from Muon Decay Versus Electroweak Fits and Cabibbo-Kobayashi-Maskawa Unitarity

Crivellin, Andreas; Hoferichter, Martin; Manzari, Claudio Andrea (2021). Fermi Constant from Muon Decay Versus Electroweak Fits and Cabibbo-Kobayashi-Maskawa Unitarity. Physical review letters, 127(7), 071801. American Physical Society 10.1103/PhysRevLett.127.071801

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The Fermi constant G F is extremely well measured through the muon lifetime, defining one of the key fundamental parameters in the standard model (SM). Therefore, to search for physics beyond the SM (BSM) via GF, the constraining power is determined by the precision of the second-best independent determination of GF. The best alternative extractions of G
F proceed either via the global electroweak (EW) fit or from superallowed β decays in combination with the Cabibbo angle measured in kaon, τ, or D decays. Both variants display some tension with G F from muon decay, albeit in opposite directions, reflecting the known tensions within the EW fit and hints for the apparent violation of Cabibbo-Kobayashi-Maskawa unitarity, respectively. We investigate how BSM physics could bring the three determinations of G F into agreement using SM effective field theory and comment on future perspectives.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Theoretical Physics
10 Strategic Research Centers > Albert Einstein Center for Fundamental Physics (AEC)

UniBE Contributor:

Hoferichter, Martin

Subjects:

500 Science > 530 Physics

ISSN:

0031-9007

Publisher:

American Physical Society

Language:

English

Submitter:

Binia Marti

Date Deposited:

23 Mar 2022 14:11

Last Modified:

25 Sep 2024 20:24

Publisher DOI:

10.1103/PhysRevLett.127.071801

PubMed ID:

34459644

BORIS DOI:

10.48350/167266

URI:

https://boris.unibe.ch/id/eprint/167266

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