Fast simulation of the forward tracking detector of HPLUS**Supported by HIRFL-CSR Project (Lanzhou, China), One Hundred Talents Program of Chinese Academy of Sciences, Knowledge Innovation Project of Chinese Academy of Sciences (KJCX2-SW-N02, KJCX2-SW-N07), Major State Basic Research Development Program (TG2000077401), and National Natural Foundation of Science (10675148,10635080)

Abstract

The necessity of installing a forward tracking detector stack is discussed for the Hadron Physics LanzhoU Spectrometer(HPLUS). A local tracker is developed to solve the multi-track finding problem. The track candidates are searched iteratively via Hough Transform. The fake tracks are removed by a least square fitting process. With this tracker we have studied the feasibility of pp → pp+ϕ(→ K+K−), a typical physical channel proposed on HPLUS. The single track momentum resolution due to the uncertainty of the positioning in FTD is 1.3%. The multiple scattering effect contributes about 20% to the momentum resolution in the FTD coverage. The width and the signal-to-background ratio of the reconstructed ϕ are 1.51 MeV and 4.36, respectively, taking into account the direct Kaon channel pp → pp + K+K− as background. The geometry coverage of FTD for f events is about 85.4%. Based on the current fast simulation and estimation, the geometrical configuration of FTD meets the physical requirement of HPLUS under the current luminosity and multiplicity conditions. The tracker is applicable in the full simulation coming next and is extendable to other tracking component of HPLUS.