Conveners
Lepton Flavor and Precision Measurements: LFL 5I
- Robert Bernstein
Lepton Flavor and Precision Measurements: LFL 6I
- Robert Bernstein
The goal of the Mu2e experiment is to test the conservation of charged lepton flavor with a search for neutrinoless muon to electron conversion in the Coulomb field of a nucleus. To extend the sensitivity of this measurement by four orders of magnitude beyond present limits, the Mu2e design incorporates several innovations to produce an intense muon beam, detect signal electrons, and reduce...
The Mu2e experiment is designed to search for New Physics in an extremely rare process of muon to electron neutrino-less conversion. The Mu2e sensitivity to New Physics heavily relies on suppressing all the background sources to a fraction on event. The dominant background at Mu2e originates from cosmic ray (CR) muons that interact or decay in the detector solenoid and produce a signal-like...
The Mu2e experiment at Fermilab seeks to observe the ultra-rare conversion of a muon to an electron in a nuclear field, which produces a monoenergetic electron with an energy close to the muon rest mass. This process violates charged lepton flavor number conservation in the Standard Model, and is a clear signal for New Physics if observed. Mu2e’s most dangerous source of background is...
The Mu2e experiment will search for neutrinoless, coherent conversion of a muon into an electron in the presence of an aluminum nucleus. This conversion process is an example of charged lepton flavor violation (CLFV), which has never been observed experimentally. Mu2e is designed to accurately detect the 105 MeV/c conversion electron (CE) momentum in a uniform 1 T magnetic field. We...
The Mu2e experiment at Fermilab will search for charged lepton flavor violation (CLFV) via muon to electron conversion, with a goal of improving the previous upper limit by four orders of magnitude and reaching unprecedented single-event sensitivities. The signal of CLFV conversion is a ~105 MeV electron, which is detected using a high-precision straw tracker. Protons produced by muon capture...
One major puzzle in particle physics is the replicated lepton families. There appears to be a ‘family symmetry’ which prevents charged lepton flavor violating (CLFV) processes. If a continuous global lepton family symmetry exists, it leads to associated Goldstone bosons, ‘familons’, through spontaneous symmetry breaking. The familon can acquire mass if this symmetry is also explicitly...
The Mu2e experiment will search for Beyond-the-Standard-Model, Charged Lepton Flavor Violation (CLFV) in muon capture $\mu^- + \text{Al}\rightarrow e^- +\text{Al}$, with a single event sensitivity surpassing the current world's best limit by 10,000 times. To report a reliable result, the number of stopped muons will be normalized to 10\% precision utilizing a combination of two $\gamma$-ray...
The AlCap experiment is an experiment conducted at PSI (Switzerland) that studies products of muon capture on aluminum, titanium. These materials are candidates for stopping targets in the next-generation of charged lepton flavor violation experiments, namely Mu2e at Fermilab and COMET at J-PARC, which will search for the neutrinoless conversion of muons to electrons in the nuclear fields....
The AlCap experiment has measured the emission rate and energy spectra of protons, deuterons, tritons and alpha particles associated with the nuclear capture of muons stopped in Al, Si, and Ti at PSI. These measurements quantify an important nuclear physics hit background to the Mu2e and COMET experiments, which will search for charged lepton flavor violation at an unprecedented level of...
Searches for charged lepton flavor violation (CLFV) are a probe of new physics beyond the Standard Model. We used existing data to set the first limits on the branching ratio of the CLFV decays $\tau \to \ell \gamma \gamma$ where $\ell=e, \mu$. The decays $\tau \to \ell X$, where $X$ is a weakly interacting boson, were also examined and improved upper bounds were obtained. The results and...
We present a search for the lepton-flavor-violating decays $B^0→\tau^\pm\ell^\mp$, where $\ell= (e,\,\mu)$, using the full data sample of $772×10^6$ $B\overline B$ pairs recorded by the Belle detector at the KEKB asymmetric-energy $e^+e^−$ collider. We use events in which one $B$ meson is fully reconstructed in a hadronic decay mode. The $\tau^\pm$ lepton is reconstructed indirectly using the...
