scholarly journals Status of the Mu2e experiment

2018 ◽  
Vol 179 ◽  
pp. 01003 ◽  
Author(s):  
S. Giovannella

The Mu2e experiment at Fermilab searches for the charged-lepton flavor violating neutrino-less conversion of a negative muon into an electron in the field of an aluminum nucleus. The dynamics of such a process is well modelled by a two-body decay, resulting in a mono-energetic electron with an energy slightly below the muon rest mass. If no events are observed, in three years of running Mu2e will improve the current limit by four orders of magnitude. Such a charged lepton flavor-violating reaction probes new physics at a scale inaccessible with direct searches at either present or planned high energy colliders. The experiment both complements and extends the current search for muon decay to electron-photon at MEG and searches for new physics at the LHC. This paper focuses on the physics motivation, the design and the status of the experiment.

2020 ◽  
Vol 234 ◽  
pp. 01010
Author(s):  
Stefano Miscetti

The Mu2e experiment aims to improve, by four orders of magnitude, current sensitivity in the search for the charged-lepton flavor violating (cLFV) neutrino-less conversion of a negative muon into an electron. The conversion process will be identified by a distinctive signature of a mono-energetic electron with energy slightly below the muon rest mass. In the Standard Model this process has a negligible rate. However, in many Beyond the Standard Model scenarios its rate is within the reach of Mu2e sensitivity. In this paper, we explain the Mu2e design guidelines and summarize the status of the experiment.


Author(s):  
Richard Bonventre

The Mu2e experiment will measure the charged-lepton flavor violating (CLFV) neutrino-less conversion of a negative muon into an electron in the field of a nucleus. Mu2e will improve the previous measurement by four orders of magnitude, reaching a 90% C.L. limit of 8\times10^{-17}8×10−17 on the conversion rate. The experiment will reach mass scales of nearly 10^4104 TeV, far beyond the direct reach of colliders. The experiment is sensitive to a wide range of new physics, complementing and extending other CLFV searches. Mu2e is under design and construction at the Muon Campus of Fermilab; we expect to start taking physics data in 2022 with 3 years of running to achieve our target sensitivity.


2020 ◽  
Vol 35 (19) ◽  
pp. 2030007
Author(s):  
Manolis Kargiantoulakis

The Mu2e experiment will search for the neutrino-less conversion of a muon into an electron in the field of an aluminum nucleus. An observation would be the first signal of charged lepton flavor violation and de facto evidence for new physics beyond the Standard Model. The clean signature of the conversion process offers an opportunity for a powerful search: Mu2e will probe four orders of magnitude beyond current limits, with real discovery potential over a wide range of well-motivated new physics models. This goal requires an integrated system of solenoids that will create the most intense muon beam in the world, and suppression of all possible background sources. The Mu2e components are currently being constructed, with the experiment planned to begin operations in the Fermilab Muon Campus within the next few years.


2014 ◽  
Vol 89 (5) ◽  
Author(s):  
Frank F. Deppisch ◽  
Nishita Desai ◽  
José W. F. Valle

2021 ◽  
Vol 2145 (1) ◽  
pp. 012018
Author(s):  
J Ineead ◽  
S Nishida ◽  
B Asavapibhop ◽  
N Suwonjandee

Abstract The electroweak b → sll (l = e, µ) transition is a flavor-changing neutral current process that mediates through a one-loop penguin diagram. The decay is considered to be a good probe for the New Physics as particles predicted in the beyond Standard Model theories can enter into the loop. The exclusive decay B → K (*) l + l − was first observed by the Belle experiment and it provides many observables such as the branching fraction, CP asymmetry, forward-backward asymmetry, and other angular observables. Recently, the LHCb experiment has reported some clue of a lepton flavor universality violation from the branching fraction ratio of the B → Kµ + µ − and B → Ke + e − decays. In this presentation, we report the status of the B → Kl + l − decay analysis at the Belle II experiment which started the data taking in 2019. We also, present an activity at the Belle II Chulalongkorn University group where we study the B → KJ/ψ decay which has the same topology as the B → Kl + l − .


2021 ◽  
Vol 81 (9) ◽  
Author(s):  
Tong Li ◽  
Michael A. Schmidt ◽  
Chang-Yuan Yao ◽  
Man Yuan

AbstractAny observation of charged lepton flavor violation (CLFV) implies the existence of new physics beyond the SM in charged lepton sector. CLFV interactions may also contribute to the muon magnetic moment and explain the discrepancy between the SM prediction and the recent muon $$g-2$$ g - 2 precision measurement at Fermilab. We consider the most general SM gauge invariant Lagrangian of $$\Delta L=0$$ Δ L = 0 bileptons with CLFV couplings and investigate the interplay of low-energy precision experiments and colliders in light of the muon magnetic moment anomaly. We go beyond previous work by demonstrating the sensitivity of the LHC, the MACE experiment, a proposed muonium-antimuonium conversion experiment, and a muon collider. Currently-available LHC data is already able to probe unexplored parameter space via the CLFV process $$pp\rightarrow \gamma ^*/Z^*\rightarrow \ell _1^\pm \ell _1^\pm \ell _2^\mp \ell _2^\mp $$ p p → γ ∗ / Z ∗ → ℓ 1 ± ℓ 1 ± ℓ 2 ∓ ℓ 2 ∓ .


Author(s):  
Yoshitaka Kuno

Abstract A new experimental search for the charged-lepton-flavor-violating process of neutrinoless muon-to-electron conversion by J-PARC E21 (the COMET experiment), which aims at a factor of 10 000 improvement over the current limit, is described, together with the physics motivation of charged lepton flavor violation. The first-stage approach of the COMET experiment (COMET Phase-I), which has recently been taken for earlier realization of the measurement, is also mentioned.


2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
◽  
K. Uno ◽  
K. Hayasaka ◽  
K. Inami ◽  
I. Adachi ◽  
...  

Abstract Charged lepton flavor violation is forbidden in the Standard Model but possible in several new physics scenarios. In many of these models, the radiative decays τ± → ℓ±γ (ℓ = e, μ) are predicted to have a sizeable probability, making them particularly interesting channels to search at various experiments. An updated search via τ± → ℓ±γ using full data of the Belle experiment, corresponding to an integrated luminosity of 988 fb−1, is reported for charged lepton flavor violation. No significant excess over background predictions from the Standard Model is observed, and the upper limits on the branching fractions, $$ \mathcal{B} $$ B (τ± → μ±γ) ≤ 4.2 × 10−8 and $$ \mathcal{B} $$ B (τ± → e±γ) ≤ 5.6 × 10−8, are set at 90% confidence level.


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