Objectives

The program SIMDET simulates the response of the LC detector for $e^+e^-$ physics as described in the Technical Design Report ¹ in a fast and flexible manner. The main objectives of the program are threefold:

• It provides physics studies groups with a tool for evaluation of the physics potential of a LC.
• It treats the detector responds in a realistic matter using a parametrisation of results from the ab initio Monte Carlo program BRAHMS.
• It is fast and provides a simple output structure, so that physics studies can be done in a straight forward and decentralized way.

The basic components of the detector are assumed to be:

• a vertex detector
• a tracker system with main tracker, forward tracker and intermediate tracker with forward disks
• an electromagnetic calorimeter
• a hadronic calorimeter
• a low-angle tagger (instrumented mask) and
• a low-angle luminosity calorimeter.

The program applies Gaussian smearing to charged particle momenta and impact parameters with resolutions obtained from the ab initio Monte Carlo program BRAHMS. The calorimetric response is treated in a way also using a parametrisation of results from the program BRAHMS. Pattern recognition is emulated by means of cross reference tables between generated particles and detector response. An energy flow algorithm defines the output of the program. If wanted, the covariance matrix and dE/dx information can be added.

SIMDET offers for event input either to use a built in interface to PYTHIA for internal event generation or to read events generated by other programs and written by subroutine LCWRITE. In the case of using PYTHIA, beamstrahlung can be switched on. The history of the event can optionally enabled.

After simulation and for the purpose of physics analysis, particles are classified as

• electrons
• photons
• muons
• charged hadrons, interpreted as pions
• neutral hadrons, interpreted as long-lived kaons
• clusters of unresolved particles.

Tracking efficiencies, charge mismeasurement and threshold energies for detector response are also taken into account either by default or with user adjustable values. Low energy muons are interpreted as pions.

The output of the program can be directed to a file using the standard output structure or a restricted form. Also, output of 'reconstructed' events can be completely suppressed or, if requested, the best estimates for the energy flow objects are stored such that the physics analysis package VECSUB can be directly used.

The program runs under the control of free format data cards with the possibility of overriding the default options.

A lot of changes and improvements were made with respect to previous versions of SIMDET; hence the old versions should be considered as obsolete. This document describes SIMDET V4 Development

The code of SIMDET V4.01 is found in ².