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:
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Journal Article
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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.
The Experiment Control System (ECS) of the LHCb Silicon Tracker sub-detectors is built on the integrated LHCb ECS framework. Although all LHCb sub-detectors use the same framework and follow the same ...guidelines, the Silicon Tracker control system uses some interesting additional features for operation and monitoring. The main details are described in this document. Since its design, the Silicon Tracker control system has been continuously evolving in a quite disorganized way. Some major maintenance activities are required in order to keep improving it. A description of those activities can also be found here.
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 D^0 --> K^- pi^+ decays to remove a curvature bias in the LHCb spectrometer.
Using three- and four-body decays of \(D\) mesons produced in semileptonic \(b\)-hadron decays, precision measurements of \(D\) meson mass differences are made together with a measurement of the ...\(D^{0}\) mass. The measurements are based on a dataset corresponding to an integrated luminosity of \(1.0 fb^{-1}\) collected in \(pp\) collisions at 7\,TeV. Using the decay \(D^0 \rightarrow K^{+} K^{-} K^{-} \pi^{+}\), the \(D^0\) mass is measured to be \(M(D^0) &=& 1864.75 \pm 0.15 \,({\rm stat}) \pm 0.11 \,({\rm syst}) \, \textrm{MeV/c^2}\). The mass differences \(M(D^{+}) - M(D^{0}) = 4.76 \pm 0.12 \,({\rm stat}) \pm 0.07 \,({\rm syst}) \, \textrm{MeV/c^2}\) and \(M(D^{+}_s) - M(D^{+}) = 98.68 \pm 0.03 \,({\rm stat}) \pm 0.04 \,({\rm syst}) \, \textrm{MeV/c^2}\) are measured using the \(D^0 \rightarrow K^{+} K^{-} \pi^{+} \pi^{-}\) and \(D^{+}_{(s)} \rightarrow K^{+}K^{-} \pi^{+}\) modes.
High symmetry epitaxial quantum dots (QDs) with three or more symmetry planes provide a very promising route for the generation of entangled photons for quantum information applications. The great ...challenge to fabricate nanoscopic high symmetry QDs is further complicated by the lack of structural characterization techniques able to resolve small symmetry breaking. In this work, we present an approach for identifying and analyzing the signatures of symmetry breaking in the optical spectra of QDs. Exciton complexes in InGaAs/AlGaAs QDs grown along the 111B crystalline axis in inverted tetrahedral pyramids are studied by polarization resolved photoluminescence spectroscopy combined with lattice temperature dependence, excitation power dependence and temporal photon correlation measurements. By combining such a systematic experimental approach with a simple theoretical approach based on a point-group symmetry analysis of the polarized emission patterns of each exciton complex, we demonstrate that it is possible to achieve a strict and coherent identification of all the observable spectral patterns of numerous exciton complexes and a quantitative determination of the fine structure splittings of their quantum states. This analysis is found to be particularly powerful for selecting QDs with the highest degree of symmetry (C3v and ) for potential applications of these QDs as polarization entangled photon sources. We exhibit the optical spectra when evolving towards asymmetrical QDs, and show the higher sensitivity of certain exciton complexes to symmetry breaking.
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