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Volume 367 - XXIX International Symposium on Lepton Photon Interactions at High Energies (LeptonPhoton2019) - Parallel Sessions
Searches for charged lepton flavor violating muon decay, MEG/MEG II experiment
T. Iwamoto
Full text: Not available
Abstract
In order to search for charged lepton flavor violating muon decay, $\mu^{+} \rightarrow e^{+} \gamma$, the MEG experiment started data taking in 2009, and finished in 2013. After the careful data analysis has been performed, it is found that the result was consistent with null signal, and the upper limit of the branching ratio of the $\mu^{+} \rightarrow e^{+} \gamma$ was set to be $4.2 \times 10^{-13}$ at 90\% CL while the final sensitivity was $5.3\times 10^{-13}$. This result is the most stringent to date, about 30 times better result
than the previous experiment, and provides important constraints on the existence of new physics beyond the standard model.
The MEG II experiment will improve the sensitivity by about an order of magnitude with higher muon beam rate and new detector technologies. The target sensitivity is $6 \times 10^{-14}$ with three years data taking. The detector R\&D has been performed seriously
since the MEG experiment was finished, and the construction of each sub-detector has almost been completed. A muon beam test will be carried out for each sub-detector
with limited electronics this autumn. The engineering run followed by the physics run will start next year after all the electronics will be available.
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