Technical design of the phase I Mu3e experiment Arndt, K.; Augustin, H.; Baesso, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2021, Letnik:
1014
Journal Article
Recenzirano
Odprti dostop
The Mu3e experiment aims to find or exclude the lepton flavour violating decay μ→eee at branching fractions above 10−16. A first phase of the experiment using an existing beamline at the Paul ...Scherrer Institute (PSI) is designed to reach a single event sensitivity of 2⋅10−15. We present an overview of all aspects of the technical design and expected performance of the phase I Mu3e detector. The high rate of up to 108 muon decays per second and the low momenta of the decay electrons and positrons pose a unique set of challenges, which we tackle using an ultra thin tracking detector based on high-voltage monolithic active pixel sensors combined with scintillating fibres and tiles for precise timing measurements.
We present the development and performance of compact scintillating fiber detectors read out with silicon photo-multipliers (Si-PMs). The compact size, fast response, and insensitivity to magnetic ...fields make these detectors suitable for a variety of applications where precise tracking and timing information is required. These detectors will be used with different particle beams (electrons, protons, heavy ions) at very high rates. In particular, we present the SciFi tracker/time of flight detector that is being developed for the Mu3e experiment at PSI (search for the lepton flavor violating decay μ→eee at very high rates). We also present the SciFi beam position detectors that will be employed in NA61 at CERN to track the incoming proton and heavy ion beam particles. We are considering different readout scenarios in which (a) each fiber is individually coupled to a single Si-PM photo-sensor and (b) fibers are arranged in columns and coupled to a Si-PM arrays.
The Mu3e Experiment Bravar, A.
Nuclear and particle physics proceedings,
June-July 2017, 2017-06-00, Letnik:
287-288
Journal Article
Recenzirano
The Mu3e experiment will search for lepton flavor violation in the neutrinoless muon decay μ+→e+e−e+ with a sensitivity down to 10−16 (90% C.L.) using the world most intense muon beam at the Paul ...Scherrer Institute. The μ+→e+e−e+ decay is strongly suppressed in the Standard Model whilst several Beyond the SM models predict observable effects accessible to the new generation of LFV experiments. The search for the μ+→e+e−e+ decay requires a large acceptance detector capable of measuring up to 2 × 109 decays of stopped muons per second with excellent momentum, space, and time resolution to suppress backgrounds below the 1016 level. The required Mu3e detector performance is possible thanks to tracking detectors based on thin monolithic active silicon pixel sensors (HV-MAPS) and very precise timing measurements using scintillating fibers and tiles both coupled to silicon photo-multipliers. The first phase of the Mu3e experiment has been recently approved. Following an intense R&D program the construction of the detector is about to start. First data taking is expected in 2019.
A precise measurement of the analyzing power AN in proton–proton elastic scattering in the region of 4-momentum transfer squared 0.001<|t|<0.032 (GeV/c)2 has been performed using a polarized atomic ...hydrogen gas jet target and the 100 GeV/c RHIC proton beam. The interference of the electromagnetic spin-flip amplitude with a hadronic spin-nonflip amplitude is predicted to generate a significant AN of 4–5%, peaking at −t≃0.003 (GeV/c)2. This kinematic region is known as the Coulomb nuclear interference region. A possible hadronic spin-flip amplitude modifies this calculable prediction. We present the first precise result of the CNI asymmetry and shape as a function of t. Our data are well described by the CNI prediction with the electromagnetic spin-flip alone and do not support the presence of a large hadronic spin-flip amplitude.