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Muon Decays

Applicant Signer Adrian
Number 163466
Funding scheme Project funding
Research institution Paul Scherrer Institut
Institution of higher education Paul Scherrer Institute - PSI
Main discipline Theoretical Physics
Start/End 01.11.2015 - 31.10.2018
Approved amount 172'508.00
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All Disciplines (2)

Discipline
Theoretical Physics
Particle Physics

Keywords (3)

muon physics; rare decays; higher-order corrections

Lay Summary (German)

Lead
Verbesserte theoretische Berechnungen sowohl zum dominanten als auch zu seltenen Zerfällen des Myons.
Lay summary
Myonen gehören zu den am intensivsten untersuchten Elementarteilchen.
Sie haben eine Lebensdauer von etwa 2 Mikrosekunden (2 millionstel
Sekunden) und zerfallen fast ausschliesslich in ein Elektron und zwei
Neutrinos. Myonen sind relativ einfach zu produzieren, was eine extrem
präzise Messung ihrer Eigenschaften erlaubt.

Am Paul Scherrer Institut ist der weltweit intensivste Myonenstrahl
vorhanden. Unter anderem wird diese Myonenquelle verwendet um
Zerfallskanäle des Myons zu untersuchen, die im Standardmodell
verboten sind. Falls solche Zerfälle gesehen werden, ist dies ein
klarer Hinweis für Physik jenseits des Standardmodells. Das Fehlen
solcher Zerfälle erlaubt es andererseits, sehr starke Einschränkungen
an Modelle jenseits des Standardmodells zu machen.

Um die maximale Information aus experimentellen Daten gewinnen zu
können, ist es wichtig, präzise theoretische Vorhersagen für
Hintergrundprozesse zu haben. Hintergrundprozesse sind Myonzerfälle,
die im Standardmodell erlaubt sind, aber sehr ähnliche experimentelle
Signaturen haben, wie die im Standardmodell verbotenen Zerfälle. Eines
der Hauptziele dieses Projektes ist es, solche Berechnungen
durchzuführen.

Ein weiteres Ziel des Projektes ist eine verbesserte Berechnung des
dominanten Zerfallskanals des Myons. Um das zu erreichen, werden
Berechnungsmethoden angewandt und weiterentwickelt, die üblicherweise
für Prozesse am Large Hadron Collider am CERN verwendet werden.
Dadurch werden nicht nur phänomenologisch wichtige Resultate für
Myonen erhalten, sondern effizientere Methoden für verwandte
Rechnungen entwickelt.
Direct link to Lay Summary Last update: 06.10.2015

Responsible applicant and co-applicants

Employees

Publications

Publication
Small-mass effects in heavy-to-light form factors
Engel T., Gnendiger C., Signer A., Ulrich Y. (2019), Small-mass effects in heavy-to-light form factors, in Journal of High Energy Physics, 2019(2), 118-118.
Fully differential NLO predictions for rare and radiative lepton decays
Ulrich Yannick (2018), Fully differential NLO predictions for rare and radiative lepton decays, in The 19th International Workshop on Neutrinos from Accelerators NUFACT2017, Uppsala University, Uppsala, SwedenProceedings of Science, SISSA.
Correlating lepton flavor universality violation in B decays with μ→eγ using leptoquarks
Crivellin Andreas, Müller Dario, Signer Adrian, Ulrich Yannick (2018), Correlating lepton flavor universality violation in B decays with μ→eγ using leptoquarks, in Physical Review D, 97(1), 015019-015019.
Fully differential NLO predictions for the radiative decay of muons and taus
Pruna G.M., Signer A., Ulrich Y. (2017), Fully differential NLO predictions for the radiative decay of muons and taus, in Physics Letters B, 772, 452-458.
To $${d}$$ d , or not to $${d}$$ d : recent developments and comparisons of regularization schemes
Gnendiger C., Signer A., Stöckinger D., Broggio A., Cherchiglia A. L., Driencourt-Mangin F., Fazio A. R., Hiller B., Mastrolia P., Peraro T., Pittau R., Pruna G. M., Rodrigo G., Sampaio M., Sborlini G., Bobadilla W. J. Torres, Tramontano F., Ulrich Y., Visconti A. (2017), To $${d}$$ d , or not to $${d}$$ d : recent developments and comparisons of regularization schemes, in The European Physical Journal C, 77(7), 471-471.
Fully differential NLO predictions for the rare muon decay
Pruna G.M., Signer A., Ulrich Y. (2017), Fully differential NLO predictions for the rare muon decay, in Physics Letters B, 765, 280-284.
Regularization-scheme dependence of QCD amplitudes in the massive case
.

Collaboration

Group / person Country
Types of collaboration
G. Luisoni MPI Munich (later CERN Geneva) Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
D. Stoekinger, TU Dresden Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Zurich PhD Seminar 2018 Talk given at a conference Fully differential predictions for lepton decays 09.03.2018 Zurich, Switzerland Ulrich Yannick;
19th International Workshop on Neutrinos from Accelerators Talk given at a conference Fully differential NLO predictions for rare and radiative lepton decays 29.09.2017 Uppsala, Sweden Ulrich Yannick;
Muon-electron scattering: Theory kickoff workshop Talk given at a conference Muon decay at NNLO: plans and interim results 04.09.2017 Padova, Italy Ulrich Yannick; Signer Adrian;
Joint Annual Meeting of SPS and OPG Talk given at a conference Fully differential NLO predictions for rare and radiative lepton decays 24.08.2017 Geneva, Switzerland Ulrich Yannick;
HEFT 2017 Talk given at a conference Charged lepton flavour violation with EFT 22.05.2017 Durham, Great Britain and Northern Ireland Signer Adrian;
1st PRISMA Interactive Research Symposium Talk given at a conference Precise Standard Model predictions for the Mu3e and MEG experiment 21.02.2017 Mainz, Germany Ulrich Yannick;
MITP Workshop GMTWO2018 Talk given at a conference Muon decay at NNLO: Status Update 20.02.2017 Mainz, Germany Signer Adrian; Ulrich Yannick;
Mu3e Meeting Talk given at a conference mu -> 3 e + X in the SM and beyond 13.02.2017 Wengen, Switzerland Signer Adrian;
PSI 2016 Poster Monte Carlo Programs for Muon Decays at NLO 18.10.2016 Villigen PSI, Switzerland Ulrich Yannick;


Self-organised

Title Date Place
Workstop/Thinkstart: To d or not to d 13.09.2016 Zurich , Switzerland

Associated projects

Number Title Start Funding scheme
178967 NNLO calculations for leptons 01.10.2018 Project funding
144252 Regularization scheme dependence of cross-section calculations for the LHC 01.11.2012 Project funding

Abstract

The study of muon decays has a very long and rich history and willcontinue to play a prominent role in particle physics. Muons arerelatively easy to produce experimentally and hence, their propertiescan be measured with with ever increasing accuracy. This developmenthas been mirrored on the theoretical side, with ever moresophisticated calculations for the standard muon decay. However, thestate-of-the art for higher-order calculations is continuouslyadvancing. Typically such techniques are used in the context ofprocesses at high-energy colliders. The aim of this project is toemploy and further develop state-of-the art techniques forhigher-order calculations to processes related to the muon decay.
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