Würzburg 2018 – scientific programme
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T: Fachverband Teilchenphysik
T 16: GRID Computing / Experimentelle Methoden I
T 16.9: Talk
Monday, March 19, 2018, 18:00–18:15, Z6 - SR 2.006
Momentum transfer reconstruction for the P2 Experiment — •Alexey Tyukin for the P2 collaboration — Institute for nuclear physics, PRISMA, Johann-Joachim-Becher-Weg 45, 55128 Mainz
The P2 experiment at the future MESA accelerator in Mainz is designed to determine the weak mixing angle, a core parameter of the Standard Model, with great precision. It will require measuring the parity violating asymmetry of elastic electron-proton scattering. The asymmetry depends on the momentum transfer Q2. Therefore a reconstruction of the electron tracks in the inhomogeneous magnetic field of the P2 detector is essential. For this, the detector will have four tracking planes of thin high voltage monolithic active pixel sensors (HV-MAPS).
This talk will cover the performance of the Q2 reconstruction. A Geant4 simulation is used to produce realistic detector hit distributions. For track reconstruction the General Broken Lines fit is used, which requires particle track propagation in an inhomogeneous magnetic field using a Runge-Kutta method. During the stepwise propagation also the track parameter error matrix is calculated by the Bugge-Myrheim method. Systematical effects producing offsets in the resulting values have to be understood for proper Q2 reconstruction. The average Q2 value of 0.006 GeV2/c2 can be reconstructed with about 4 % uncertainty for a single event, leading to a high overall precision due to large electron rates of the experiment.