Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

...

This file contains the parameters for smearing the transverse momentum p of charged tracks according to the simple formula ?p/p 2 = a + b/psin? .  This method of smearing track parameters is
enabled by setting the MCFast class constructor argument simple=true.  The file parameter ConstantTerm = a and the file parameter ThetaTerm = b .  By default, the errors for the track angles and  impact pararameters are taken from the files defined in TrackParameters.properties.  However, the angle and impact parameter errors can be scaled relative to these default errors using the SimpleTrack.properties parameters TanLambdaErrorScale, PhiErrorScale, D0ErrorSCale and Z0ErrorScale.

Reconstruction Files

Digisim

A digisim.steer file is needed in the digisim directory. This file contains timing and threshold
cuts for the hits in the calorimeters. Using the same file as a previous detector is fine, with
the follwing caveats: Scintillator and gas calorimeters have different hit thresholds, so use the
appropriate file. Also, files for detectors prior to sid01 do not contain muon calorimeter
information.

Calorimeter Sampling Fractions

Sampling fractions need to be provided for each calorimeter defined in the detector. Currently there
needs to be one file for each calorimeter in the directory SamplingFractions. The files may contain
different values for different layers or ranges of layers (needed for Ecal), and there is currently only one value per calorimeter. This is clearly not correct for the electromagnetic calorimeters. (The values for the electromagnetic sampling fractions for the sid and cdc designs were obtained from 10GeV photons at theta of 25 and 90 degrees.) Sampling fractions for the hadron calorimeters are harder to define, especially for digital readout. Input is welcomedand a digital flag for
the hits to be treated digitally. These numbers are used to give an energy estimate of hits and
clusters without angle or particle type corrections.

Generating the numbers

Once the digisim.steer file is in place, a driver QSFCalibrationFromData (soon to be in CVS) can be
run to generate the numbers for each calorimeter (or sub-calorimeter). The procedure minimizes
dE/sqrtE per event, using only the calorimeter information. Three sets of numbers are generated.
(Ecal+Hcal, Ecal+Hcal+Muon, Ecal+Hcal+MuonEndcap) The input files must be the qq events at fixed
energies. The numbers will vary significantly depending on the cm energy, so typically the driver
is run over a combination of 10k events each at 100,200,500 GeV cm energy. The numbers can then be
placed in the Sampling fraction files.

Calibration files

The calibration files reside in the photonCalibration and hadronCalibration directories. The
constants are derived by a driver (QCalibrationFromData, soon to be in CVS) which uses the cheat
reconstruction. Therefore, in addition to the sampling fraction files, all the FastMC files must
also exist. The procedure is to attach calorimeter hits to the neutral particles, calculate sampling
fractions independently for photons and neutral hadrons minimizing dE/sqrtE assuming an angle
correction, and calculate response corrections (for nonlinearity). The calibration depend on the
distributions in energy, angle, and particle type, and is typically run on the ZZ events at 500 GeV.
The files photon-(slic version).properties and nh-(slic version).properties can then be created, and
are used by the classes QPhotonClusterEnergyCalculator and QNeutralHadronClusterEnergyCalculator.

LongitudinalHMatrix

To run the pflow reconstructions, the file LongitudinalHMatrix.hmx is needed. Ask Norman Graf.