Studies to upgrade the silicon tracker of the Belle II experiment

Sumitted to PubDB: 2021-06-25

Category: Master Thesis, Visibility: Public

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Authors	Jerome Baudot, Tristan Fillinger
Date	Jan. 1, 2019
Belle II Number	BELLE2-MTHESIS-2021-022
Abstract	Various upgrade options for the vertex detector of the Belle II experiment are studied in this report. First, using a tool based on simplified calculations of tracking performances, we observe a factor two improvement with respect to the current Belle II tracker on track parameter resolutions, by reducing the radius and thickness of the beampipe as well as the material budget of the tracker layers. A new geometry, full simulation and track reconstruction are implemented within the Belle II software. This new geometry does not yet feature all modi cations and the improvements obtained have lesser amplitude. The complete track reconstruction allows however a detailed study of the impact of the beam induced background on the performances, showing reconstruction efficiencies of 98.5% without background, 98.2% with one, 97.2% with two and 88.9% with three times the nominal expected background level. Finally, by using a decay channel where new physics may be revealed, we show that if the reconstruction efficiency drops to 88.9% when nominal luminosity will be reached, the last two years of operation of the Belle II experiment will not bring any additional statistical power.
Conference	Strasbourg