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Related papers: Shape function in QED and bound muon decays

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We have determined in detail the electron spectrum in the decay of bound muons. These results are especially relevant for the upcoming muon-electron conversion experiments.

High Energy Physics - Phenomenology · Physics 2015-06-03 Andrzej Czarnecki , Xavier Garcia i Tormo , William J. Marciano

When a muon bound in an atom decays, there is a small probability that the daughter electron remains bound. That probability is evaluated. Surprisingly, a significant part of the rate is contributed by the negative energy component of the…

High Energy Physics - Phenomenology · Physics 2020-10-21 M. Jamil Aslam , Andrzej Czarnecki , Guangpeng Zhang , Anna Morozova

The spectrum of electrons from muons decaying in an atomic bound state is significantly modified by their interaction with the nucleus. Somewhat unexpectedly, its first measurement, at the Canadian laboratory TRIUMF, differed from basic…

High Energy Physics - Phenomenology · Physics 2015-06-22 Andrzej Czarnecki , Matthew Dowling , Xavier Garcia i Tormo , William J. Marciano , Robert Szafron

Bound-muon decays are a powerful probe of new physics, making precise theoretical predictions for their spectra essential. While QED corrections significantly affect the shape of the spectra, their calculation is extremely challenging below…

High Energy Physics - Phenomenology · Physics 2025-10-31 Duarte Fontes , Robert Szafron

O(alpha^2 ln^2(m_mu/m_e)) QED corrections to the electron spectrum and angular distribution in muon decay are evaluated. Impact on the determination of Michel parameters is estimated. Current theoretical uncertainty in the muon decay…

High Energy Physics - Phenomenology · Physics 2011-03-31 Andrej Arbuzov , Andrzej Czarnecki , Andrei Gaponenko

For the bound-muon decay process, the study of atomic effects on the electron spectrum near its endpoint is performed within the framework of the Fermi effective theory. The analysis takes into account for corrections due to…

Atomic Physics · Physics 2025-06-04 M. Y. Kaygorodov , Y. S. Kozhedub , A. V. Malyshev , A. O. Davydov , Y. Wu , S. B. Zhang

QED radiative corrections to polarized muon decay spectrum are considered. Leading and next--to--leading logarithmic approximations are used. Exponentiation of soft radiation is discussed. The present theoretical uncertainty of the spectrum…

High Energy Physics - Phenomenology · Physics 2009-11-07 Andrej Arbuzov

We determine the $\mathcal{O}(\alpha)$ correction to the energy spectrum of electrons produced in the decay of muons bound in atoms. We focus on the high-energy end of the spectrum that constitutes a background for the muon-electron…

High Energy Physics - Phenomenology · Physics 2016-01-20 Robert Szafron , Andrzej Czarnecki

We show how radiative QCD corrections calculated in terms of quarks can be incorporated at the hadron level in inclusive semileptonic B-meson decays. The bound state effects are described by a momentum distribution function of the $b$…

High Energy Physics - Phenomenology · Physics 2011-09-13 Changhao Jin , Emmanuel A. Paschos

The decay $\mu^-\to e^- \bar{\nu}_e\nu_\mu$ of a muon that is bound to a nucleus poses an unavoidable background for experiments such as Mu2e, COMET, and DeeMe searching for lepton-flavor-violating $\mu^-\to e^-$ conversion and thus…

High Energy Physics - Phenomenology · Physics 2022-03-21 Julian Heeck , Robert Szafron , Yuichi Uesaka

We compute the complete O(alpha^2) QED corrections to the electron energy spectrum in unpolarized muon decay, including the full dependence on the electron mass. Our calculation reduces the theoretical uncertainty on the electron energy…

High Energy Physics - Phenomenology · Physics 2008-11-26 Charalampos Anastasiou , Kirill Melnikov , Frank Petriello

The first order QED corrections to the polarized muon decay spectrum are considered. The exact dependence on electron and muon masses is kept. Numerical results are presented.

High Energy Physics - Phenomenology · Physics 2009-11-07 A. B. Arbuzov

Predictions for the muon decay spectrum are usually derived from the derivative-free Hamiltonian. However, it is not the most general form of the possible interactions. Additional simple terms with derivatives can be introduced. In this…

High Energy Physics - Phenomenology · Physics 2007-05-23 M. V. Chizhov

In this study, we theoretically investigated x-ray spectra from the radiative decay of muonic deuterium molecules in resonance states dd$\mu^\ast$, which plays an important role in a new kinetic model of muon catalyzed fusion ($\mu$CF). The…

Atomic Physics · Physics 2025-01-23 Takuma Yamashita , Kazuhiro Yasuda , Yasushi Kino

Experimental searches for lepton-flavor-violating coherent muon-to-electron conversion in the field of a nucleus, have been proposed to reach the unprecedented sensitivity of 10^(-16) - 10^(-18) per stopped muon. At that level, they probe…

High Energy Physics - Phenomenology · Physics 2011-08-08 Andrzej Czarnecki , Xavier Garcia i Tormo , William J. Marciano

We consider the O(alpha^2) hadronic corrections to the energy spectrum of the decay electron in muon decay. We find that the correction can be described, within good approximation, by a linear function in the electron energy. Explicit…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. I. Davydychev , K. Schilcher , H. Spiesberger

An interaction of a pseudoscalar particle with two photons induced by an external electromagnetic field is used to study the photon decay $\gamma \to \gamma a$ where a is a pseudoscalar particle associated with the Peccei-Quinn U(1)…

High Energy Physics - Phenomenology · Physics 2009-10-31 N. V. Mikheev , A. Ya. Parkhomenko , L. A. Vassilevskaya

We illustrate how to apply modern effective field theory techniques and dimensional regularization to factorise the various scales which appear in QED bound states at finite temperature. We focus here on the muonic hydrogen atom. Vacuum…

High Energy Physics - Phenomenology · Physics 2010-11-11 Miguel Angel Escobedo , Joan Soto

We consider the impact of O(alpha^2) hadronic corrections to the energy spectrum of the decay electron in muon decay. We find that the correction can be described, within good approximation, by a linear function in the electron energy.…

High Energy Physics - Phenomenology · Physics 2009-01-07 A. I. Davydychev , K. Schilcher , H. Spiesberger

Environmental effects on the muon lifetime are described. A general theorem on the cancellation of bound state phase space suppression and final state interaction enhancement is illustrated for muonium and muonic atoms. Lessons from those…

High Energy Physics - Phenomenology · Physics 2007-05-23 William J. Marciano
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