Searching for the Muon Decay to Three Electrons with the Mu3e Experiment

Mu3e is a dedicated experiment designed to find or exclude the charged lepton flavor violating <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="sans-serif">μ</mi><m...

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Main Authors: Cristina Martin Perez, Luigi Vigani
Format: Article
Language:English
Published: MDPI AG 2021-11-01
Series:Universe
Subjects:
Online Access:https://www.mdpi.com/2218-1997/7/11/420
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author Cristina Martin Perez
Luigi Vigani
author_facet Cristina Martin Perez
Luigi Vigani
author_sort Cristina Martin Perez
collection DOAJ
description Mu3e is a dedicated experiment designed to find or exclude the charged lepton flavor violating <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="sans-serif">μ</mi><mo>→</mo></mrow></semantics></math></inline-formula> eee decay at branching fractions above <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mrow><mo>−</mo><mn>16</mn></mrow></msup></semantics></math></inline-formula>. The search is pursued in two operational phases: Phase I uses an existing beamline at the Paul Scherrer Institute (PSI), targeting a single event sensitivity of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2</mn><mspace width="0.166667em"></mspace><mo>·</mo><mspace width="0.166667em"></mspace><msup><mn>10</mn><mrow><mo>−</mo><mn>15</mn></mrow></msup></mrow></semantics></math></inline-formula>, while the ultimate sensitivity is reached in Phase II using a high intensity muon beamline under study at PSI. As the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="sans-serif">μ</mi><mo>→</mo></mrow></semantics></math></inline-formula> eee decay is heavily suppressed in the Standard Model of particle physics, the observation of such a signal would be an unambiguous indication of the existence of new physics. Achieving the desired sensitivity requires a high rate of muons (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mn>8</mn></msup></semantics></math></inline-formula> stopped muons per second) along with a detector with large kinematic acceptance and efficiency, able to reconstruct the low momentum of the decay electrons and positrons. To achieve this goal, the Mu3e experiment is mounted with an ultra thin tracking detector based on monolithic active pixel sensors for excellent momentum and vertex resolution, combined with scintillating fibers and tiles for precise timing measurements.
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spelling doaj.art-6620a8f4cec74289844f4b0559ae7ac02023-11-23T01:50:22ZengMDPI AGUniverse2218-19972021-11-0171142010.3390/universe7110420Searching for the Muon Decay to Three Electrons with the Mu3e ExperimentCristina Martin Perez0Luigi Vigani1Institute for Particle Physics and Astrophysics, ETH Zurich, 8049 Zurich, SwitzerlandPhysics Institute, University of Heidelberg, 69120 Heidelberg, GermanyMu3e is a dedicated experiment designed to find or exclude the charged lepton flavor violating <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="sans-serif">μ</mi><mo>→</mo></mrow></semantics></math></inline-formula> eee decay at branching fractions above <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mrow><mo>−</mo><mn>16</mn></mrow></msup></semantics></math></inline-formula>. The search is pursued in two operational phases: Phase I uses an existing beamline at the Paul Scherrer Institute (PSI), targeting a single event sensitivity of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2</mn><mspace width="0.166667em"></mspace><mo>·</mo><mspace width="0.166667em"></mspace><msup><mn>10</mn><mrow><mo>−</mo><mn>15</mn></mrow></msup></mrow></semantics></math></inline-formula>, while the ultimate sensitivity is reached in Phase II using a high intensity muon beamline under study at PSI. As the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="sans-serif">μ</mi><mo>→</mo></mrow></semantics></math></inline-formula> eee decay is heavily suppressed in the Standard Model of particle physics, the observation of such a signal would be an unambiguous indication of the existence of new physics. Achieving the desired sensitivity requires a high rate of muons (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mn>8</mn></msup></semantics></math></inline-formula> stopped muons per second) along with a detector with large kinematic acceptance and efficiency, able to reconstruct the low momentum of the decay electrons and positrons. To achieve this goal, the Mu3e experiment is mounted with an ultra thin tracking detector based on monolithic active pixel sensors for excellent momentum and vertex resolution, combined with scintillating fibers and tiles for precise timing measurements.https://www.mdpi.com/2218-1997/7/11/420Mu3emuonscharged lepton flavor violationPSI
spellingShingle Cristina Martin Perez
Luigi Vigani
Searching for the Muon Decay to Three Electrons with the Mu3e Experiment
Universe
Mu3e
muons
charged lepton flavor violation
PSI
title Searching for the Muon Decay to Three Electrons with the Mu3e Experiment
title_full Searching for the Muon Decay to Three Electrons with the Mu3e Experiment
title_fullStr Searching for the Muon Decay to Three Electrons with the Mu3e Experiment
title_full_unstemmed Searching for the Muon Decay to Three Electrons with the Mu3e Experiment
title_short Searching for the Muon Decay to Three Electrons with the Mu3e Experiment
title_sort searching for the muon decay to three electrons with the mu3e experiment
topic Mu3e
muons
charged lepton flavor violation
PSI
url https://www.mdpi.com/2218-1997/7/11/420
work_keys_str_mv AT cristinamartinperez searchingforthemuondecaytothreeelectronswiththemu3eexperiment
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