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

Crivellin, Andreas; Hoferichter, Martin; Manzari, Claudio Andrea

doi:10.1103/physrevlett.127.071801

Cited by 67 publications

(35 citation statements)

References 115 publications

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“…While the anomalies in semi-leptonic B decays and the anomalous magnetic moment of the muon point towards NP related to second-and third-generation fermions, the CAA and the CMS di-lepton excess can be related to first-generation quarks and leptons, with simultaneous explanations possible in terms of the effective dimension-6 operator Q (3) q [62]. Similarly, explanations of the CAA via modified W -u-d couplings also require NP related to first generation-quarks [1,[63][64][65].…”

Section: Introductionmentioning

confidence: 99%

First-generation new physics in simplified models: from low-energy parity violation to the LHC

Crivellin

Hoferichter

Kirk

et al. 2021

J. High Energ. Phys.

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New-physics (NP) constraints on first-generation quark-lepton interactions are particularly interesting given the large number of complementary processes and observables that have been measured. Recently, first hints for such NP effects have been observed as an apparent deficit in first-row CKM unitarity, known as the Cabibbo angle anomaly, and the CMS excess in $$ q\overline{q} $$ q q ¯ → e+e−. Since the same NP would inevitably enter in searches for low-energy parity violation, such as atomic parity violation, parity-violating electron scattering, and coherent neutrino-nucleus scattering, as well as electroweak precision observables, a combined analysis is required to assess the viability of potential NP interpretations. In this article we investigate the interplay between LHC searches, the Cabibbo angle anomaly, electroweak precision observables, and low-energy parity violation by studying all simplified models that give rise to tree-level effects related to interactions between first-generation quarks and leptons. Matching these models onto Standard Model effective field theory, we derive master formulae in terms of the respective Wilson coefficients, perform a complete phenomenological analysis of all available constraints, point out how parity violation can in the future be used to disentangle different NP scenarios, and project the constraints achievable with forthcoming experiments.

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Section: Introductionmentioning

confidence: 99%

First-generation new physics in simplified models: from low-energy parity violation to the LHC

Crivellin

Hoferichter

Kirk

et al. 2021

J. High Energ. Phys.

Self Cite

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show abstract

“…See Refs. [31,32,33] for the experimental constraints. The muon decay operators from the couplings with the right-handed neutrinos are suppressed by the heavy-light neutrino mixings, which will be studied in the context of the left-right model later.…”

Section: Other Modelsmentioning

confidence: 99%

Transverse positron polarization in the polarized $μ^+$ decay related with the muonium-to-antimuonium transition

Fukuyama¹,

Mimura²,

Uesaka³

2022

Preprint

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The constructions of the new high-intensity muon beamlines are progressing in facilities around the world, and new physics searches related to the muons are expected. The facilities can observe the transverse positron polarization of the polarized µ + decay to test the standard model. The transition of muonium into antimuonium (Mu-to-Mu), which is one of the interesting possibilities in the models beyond the standard model, can be also tested. The near-future observation of the transition gives us a great impact since it indicates that there is a discrete symmetry in the lepton sector. If the Mu-to-Mu transition operator is generated, a new muon decay operator can exist and it may interfere with the standard model muon decay operator to induce the corrections to the transverse positron polarization in the µ + decay. In this paper, we examine the possibility that the Mu-to-Mu transition and the correction to the transverse positron polarization are related, and we show that those two are related in the model of neutral flavor gauge boson. We also investigate the models to generate the Mu-to-Mu transition, such as an inert SU(2) L doublet, SU(2) L triplet for the type-II seesaw model, dilepton gauge boson, and left-right model. The non-zero value of the transverse polarization for one of the two directions, P T 2 , violates the time-reversal invariance, and the experimental constraint of the electron electric dipole moment can provide a severe constraint on P T 2 depending on the model.

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“…In particular it is unclear whether one can construct a viable BSM scenario, given the current LHC constraints from pp → eν [2,3]. Nevertheless, in light of the FGN result, the recent hints for BSM effects in CKM unitarity tests [10][11][12][13], and more generally in context of ongoing and future β-decay experiments and collider measurements, it is interesting to ask what a signal of BSM charged-currents would imply for other complementary experiments. For instance, refs.…”

Section: Jhep08(2021)128mentioning

confidence: 99%

Sterile neutrinos with non-standard interactions in β- and 0νββ-decay experiments

Dekens

Vries

Tong

2021

J. High Energ. Phys.

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Charged currents are probed in low-energy precision β-decay experiments and at high-energy colliders, both of which aim to measure or constrain signals of beyond-the-Standard-Model physics. In light of future β-decay and LHC measurements that will further explore these non-standard interactions, we investigate what neutrinoless double-β decay (0νββ) experiments can tell us if a nonzero signal were to be found. Using a recently developed effective-field-theory framework, we consider the effects that interactions with right-handed neutrinos have on 0νββ and discuss the range of neutrino masses that current and future 0νββ measurements can probe, assuming neutrinos are Majorana particles. For non-standard interactions at the level suggested by recently observed hints in β decays, we show that next-generation 0νββ experiments can determine the Dirac or Majorana nature of neutrinos, for sterile neutrino masses larger than $$ \mathcal{O}(10) $$ O 10 eV.

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

Cited by 67 publications

References 115 publications

First-generation new physics in simplified models: from low-energy parity violation to the LHC

First-generation new physics in simplified models: from low-energy parity violation to the LHC

Transverse positron polarization in the polarized $μ^+$ decay related with the muonium-to-antimuonium transition

Sterile neutrinos with non-standard interactions in β- and 0νββ-decay experiments

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