Application of vertex and mass constraints in track-based alignment Amoraal, J.; Blouw, J.; Blusk, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2013, Letnik:
712
Journal Article
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Odprti dostop
The software alignment of planar tracking detectors using samples of charged particle trajectories may lead to global detector distortions that affect vertex and momentum resolution. We present an ...alignment procedure that constrains such distortions by making use of samples of decay vertices reconstructed from two or more trajectories and putting constraints on their invariant mass. We illustrate the method by using a sample of invariant-mass constrained vertices from D0→K−π+ decays to remove a curvature bias in the LHCb spectrometer.
Radiation hardness of the LHCb Outer Tracker van Eijk, D.; Bachmann, S.; Bauer, Th ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2012, Letnik:
685
Journal Article
Recenzirano
Odprti dostop
This paper presents results on the radiation hardness of the LHCb Outer Tracker (OT) during LHC operation in 2010 and 2011. Modules of the OT have shown to suffer from ageing effects that lead to ...gain loss, after irradiation in the laboratory. Under irradiation at moderate intensities an insulating layer is formed on the anode wire of the OT straw cells. This ageing effect is caused by contamination of the counting gas due to outgassing of the glue used in the construction of the OT modules. Two methods to monitor gain stability in the OT are presented: module scans with radioactive sources and the study of hit efficiency as a function of amplifier threshold. No gain loss is observed after receiving 1.3fb−1 of integrated luminosity corresponding to an integrated charge of 0.055C/cm in the hottest spot of the detector.
This letter of intent proposes an experiment to search for an electric dipole moment of the muon based on the frozen-spin technique. We intend to exploit the high electric field, \(E=1{\rm GV/m}\), ...experienced in the rest frame of the muon with a momentum of \(p=125 {\rm MeV/}c\) when passing through a large magnetic field of \(|\vec{B}|=3{\rm T}\). Current muon fluxes at the \(\mu\)E1 beam line permit an improved search with a sensitivity of \(\sigma(d_\mu)\leq 6\times10^{-23}e{\rm cm}\), about three orders of magnitude more sensitivity than for the current upper limit of \(|d_\mu|\leq1.8\times10^{-19}e{\rm cm}\)\,(C.L. 95\%). With the advent of the new high intensity muon beam, HIMB, and the cold muon source, muCool, at PSI the sensitivity of the search could be further improved by tailoring a re-acceleration scheme to match the experiments injection phase space. While a null result would set a significantly improved upper limit on an otherwise un-constrained Wilson coefficient, the discovery of a muon EDM would corroborate the existence of physics beyond the Standard Model.
The Mu3e experiment aims to find or exclude the lepton flavour violating decay \(\mu \rightarrow eee\) 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 \(2\cdot 10^{-15}\). 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 \(10^{8}\) 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.
The Mu3e experiment is searching for the charged lepton flavour violating decay \( \mu^+\rightarrow e^+ e^- e^+ \), aiming for an ultimate sensitivity of one in \(10^{16}\) decays. In an environment ...of up to \(10^9\) muon decays per second the detector needs to provide precise vertex, time and momentum information to suppress accidental and physics background. The detector consists of cylindrical layers of \(50\, \mu\text{m}\) thin High Voltage Monolithic Active Pixel Sensors (HV-MAPS) placed in a \(1\,\text{T}\) magnetic field. The measurement of the trajectories of the decay particles allows for a precise vertex and momentum reconstruction. Additional layers of fast scintillating fibre and tile detectors provide sub-nanosecond time resolution. The MuPix8 chip is the first large scale prototype, proving the scalability of the HV-MAPS technology. It is produced in the AMS aH18 \(180\, \text{nm}\) HV-CMOS process. It consists of three sub-matrices, each providing an untriggered datastream of more than \(10\,\text{MHits}/\text{s}\). The latest results from laboratory and testbeam characterisation are presented, showing an excellent performance with efficiencies \(>99.6\,\text{\%}\) and a time resolution better than \(10\, \text{ns}\) achieved with time walk correction.
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