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Gaponenko, Andrei

Publications and source records attributed to Gaponenko, Andrei.

The Mu2e experiment

Mu2e will search for coherent, neutrinoless conversion of muons into electrons in the nucleus field of aluminum with a sensitivity improvement of a factor of 10,000 over existing limits. Probing the charged lepton flavor-violating reaction at such sensitivity may uncover new physics at a scale unreachable by direct searches at current or planned high-energy colliders. The experiment complements and extends the current studies at MEG-II and the LHC. I will present the physics motivation for Mu2e, as well as the design and construction status of the experiment.

Gaponenko, Andrei↗

A practical way to regularize unfolding of sharply varying spectra with low data statistics

Unfolding is a well-established tool in particle physics. However, a naive application of the standard regularization techniques to unfold the momentum spectrum of protons ejected in the process of negative muon nuclear capture led to a result exhibiting unphysical artifacts. A finite data sample limited the range in which unfolding can be performed, thus introducing a cutoff. A sharply falling “true” distribution led to low data statistics near the cutoff, which exacerbated the regularization bias and produced an unphysical spike in the resulting spectrum. An improved approach has been developed to address these issues and is illustrated using a toy model. The approach uses full Poisson likelihood of data, and produces a continuous, physically plausible, unfolded distribution. Here, the new technique has a broad applicability since sharply falling spectra are common.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Statistical Measurement of Longitudinal Beam Halo in Fermilab Recycler

The formation of non-Gaussian halo in both the transverse and longitudinal dimensions of beam bunches has been notoriously difficult both the model and to measure. We present a technique to measure the longitudinal halo of 2.5 MHz bunches in the Fermilab Recycler, which have been formed for the g-2 anomalous magnetic moment experiment. While out of time beam is not a particular concern to this experiment, it is a key issue for the subsequent Mu2e rare muon decay experiment, which will use the same bunch formation procedure. Our measurement relies on a statistical technique, in which a small fraction of the beam is scattered from the primary collimation foil in the recycler, and then is detected by a charge telescope consisting of quartz Cherenkov radiators and photomultiplier tubes. By integrating over many revolutions, the time profile of longitudinal halo (out-of-time beam) can be measured down to less than a 10⁻⁵ fractional level, relative to in-time beam. These results can then be compared to simulations.

43 PARTICLE ACCELERATORS↗

Quantum Sensing for High Energy Physics

Report of the first workshop to identify approaches and techniques in the domain of quantum sensing that can be utilized by future High Energy Physics applications to further the scientific goals of High Energy Physics.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗