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2000 fb -1 SM Data Sample at Ecm=500 GeV
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Introduction
Stdhep files for an a 2000 fb -1 Ecm=500 GeV SM data sample assuming a 120 GeV Higgs mass are
available at ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/StandardModel/ .
There are 487,603,537 events (250 fb -1 luminosity) with -80% electron/ +30% positron polarization,
and 474,837,805 events (250 fb -1 luminosity) with +80% electron/ -30% positron polarization.
whizdata/ILC500/ . The WHIZARD Monte Carlo version 1.40 is used for parton generation. The Makefile and build log files for
this implementation of WHIZARD can be found in ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/StandardModel/whizard-v1r4p0
. These
files are built from a 2000 fb -1 equivalent lumi SM data sample which can be accessed via the directory
The events on these files are
produced assuming 100% polarization for the initial state electron and positron; different files correspond to different polarization sign combinations.
A complete list of processes can be found in ftp://ftp-lcd.slac.stanford.edu/ilc/whizdataILC500/ILC500/ .
Event Weight
Due to the presence of some high cross section processes the events are not completely unweighted.
The event weight must therefore always be considered when analyzing events.
This weight is stored in the variable EVENTWEIGHTLH in the stdhep common block HEPEV4.
Process Identification
Events corresponding to hundreds of different processes are stored in random order in the stdhep files. For each event
the variable IDRUPLH from the stdhep common block HEPEV4 is used to identify the process.
Suppose that an event StandardModel/integ_index_0500_01 . The four columns are process_id,
initial_state, the variable IDRUPLH, and a bit indicating whether or not events were produced for this initial state polarization combination.
Suppose that a process has IDRUPLH=14995 . The information about the generation of this eventdata sample
can be found in the directory ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/StandardModel/run_output/w14995/run_01/ .
For example the log file is ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/StandardModel/run_output/w14995/run_01/whizard.log ,
the whizard input file is ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/StandardModel/run_output/w14995/run_01/whizard.in
and cross section information is in ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/StandardModel/run_output/w14995/run_01/whizard.n3n3n3n3ss_o.out
A complete list of processes and their IDRUPLH value can be found in
ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/StandardModel/integ_index_0500_01 . The four columns are process_id, initial_state, IDRUPLH, and a bit indicating whether or not events were produced for this initial state polarization combination.
Electron/Positron Beam Properties: Beamstrahlung and LINAC Energy Spread
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The massless assumption for the first and second fermion generations can produce some odd results given the kinematic cut values we have chosen. For example, the cross section for gamma gamma -> tau tau is significantly larger than the cross section for gamma gamma -> mu mu since the cut value of 4 GeV for default_mass_cut and default_q_cut is much larger than the tau mass.
Also the cross section for gamma gamma -> qq is suppressed relative to the corresponding cross section for lepton pair
production because the cut value of 10 GeV for default_jet_cut is larger than the cut value of 4 GeV for default_mass_cut .
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.
Derived stdhep files.
There are over 3500 files in ftp://ftp-lcd.slac.stanford.edu/ilc/whizdata/ILC500/, each produced with 100% electron and positron polarization. To use these
stdhep files in practice one must read the correct number of events from a subset of these files, or read a derived stdhep file. A derived stdhep file is built from the files
in ftp://ftp-lcd.slac.stanford.edu/ilc/whizdata/ILC500/ and corresponds to particular subset of final states with a particular initial state electron and positron polarization
combination (such as -80% electron and +30% positron).
Event Weight
Due to the presence of some high cross section processes, the events in a derived stdhep file are not completely unweighted.
The event weight must therefore always be considered when analyzing events.
This weight is stored in the variable EVENTWEIGHTLH in the stdhep common block HEPEV4.
Process Identification
For each event in a derived stdhep file the variable IDRUPLH from the common block HEPEV4 is used to identify the process. (See the
description of IDRUPLH variable in the introduction above.)
Derived stdhep files representing all SM processes with randomized final states.
A series of derived stdhep files have been produced which represent all SM process at Ecm=500 GeV. Different final states appear randomly.
There are 487,603,537 events (250 fb -1 luminosity) with -80% electron / +30% positron polarization,
and 474,837,805 events (250 fb -1 luminosity) with +80% electron / -30% positron polarization.
Defining your own Ecm=500 GeV derived stdhep files.
You can build your own subsample of the full 2 ab-1 SM dervied stdhep files by filling out an input card file suc .
FAQ
Whizard has no gluon emission by default, leading to potentially incorrect multiplicity distributions.
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