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h1. 2000 fb ^\-1^ SM Data Samples at Ecm= 250 & 500 GeV
h2. Introduction
Stdhep files for 2000 fb ^\-1^ Standard Model data samples at Ecm= 250 & 500 GeV have been produced and are currently located on SLAC mass storage.
A complete list of the processes can be found in [ftp://ftp-lcd.slac.stanford.edu/ilc2/whizdata/ILC250/doc/integ_index_0250_01] and
[ftp://ftp-lcd.slac.stanford.edu/ilc2/whizdata/ILC500/doc/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 particular initial state polarization sign combination.
Subsets of these events are available via ftp; please see [the table of derived stdhep files|#derivedfiles].
{anchor:idruplh}
The events are produced assuming 100% polarization for the initial state electron and positron; different files for the same final state correspond to different polarization sign combinations. The variable IDRUPLH indexes the different final states and polarizations. Assume, for example, that a process has IDRUPLH=14995 . The stdhep file is [ftp://ftp-lcd.slac.stanford.edu/ilc2/whizdata/ILC500/w14995_01.stdhep] and the information about the generation of this file can be found in the directory [ftp://ftp-lcd.slac.stanford.edu/ilc2/whizdata/ILC500/doc/run_output/w14995/run_01/] .
The log file is [ftp://ftp-lcd.slac.stanford.edu/ilc2/whizdata/ILC500/doc/run_output/w14995/run_01/whizard.log] ,
the whizard input file is [ftp://ftp-lcd.slac.stanford.edu/ilc2/whizdata/ILC500/doc/run_output/w14995/run_01/whizard.in]
and cross section information is in [ftp://ftp-lcd.slac.stanford.edu/ilc2/whizdata/ILC500/doc/run_output/w14995/run_01/whizard.n3n3n3n3ss_o.out]
The [WHIZARD Monte Carlo|http://whizard.event-generator.org/] version 1.40 is used for parton generation for all processes except SUSY processes. WHIZARD version 1.51 is used for SUSY processes. For processes with (without) an on-shell Higgs boson in the final state the Higgs mass is assumed to be 120 GeV (2000 GeV). The Makefile and build log files for this implementation of WHIZARD can be found in ftp://ftp-lcd.slac.stanford.edu/ilc2/whizdata/ILC500/doc/whizard-v1r4p0 .
h2. Electron/Positron Beam Properties: Beamstrahlung and LINAC Energy Spread
The following lines in whizard.in control the properties of the colliding electron/positron beams:
USER_spectrum_on = T
USER_spectrum_mode = \-2
The first line indicates that a user-supplied function is used to simulate the beams. A copy of this function can
be found in [ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/StandardModel/whizard-src/user.f90]
The absolute value of USER_spectrum_mode determines which energy spectrum is used, with the sign \+/\- indicating
electron/positron beam, respectively. For the 500 GeV SM data sample this absolute value is always 2, and corresponds
to the Guinea-Pig data contained in the directory [ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/StandardModel/guinea-pig/ilc_0500_may05_run05_seed06/]
This spectrum represents the default ILC design for Ecm=500 GeV circa August 2005, and includes both incoming LINAC
energy spread and beamstrahlung.
h2. Final State Parton Showering and Fragmentation
PYTHIA 6.205 is used for final state QED/QCD parton showering and for the fragmentation of quarks and gluons. Parton showering is performed for all final state fermions with the exception of electrons. Final state QED showering of electrons is normally turned off because the PYTHIA final state showering code indiscriminately uses the invariant mass of final state fermion-antifermion pairs for the maximum virtuality scale; however, PYTHIA final state QED showering of electrons was turned on for all Ecm = 250 GeV processes so that its effects could be studied in e+e- --> e+e-H. Otherwise default parameters are used for parton showering and fragmentation.
The interface to PYTHIA is contained in [ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/StandardModel/whizard-src/user.f90] . The source code for referenced subroutines can be found in ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/StandardModel/a6f/include .
Color flow information was not available in WHIZARD 1.40, and so kinematic and parton id information is used to identify color singlet systems (see ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/StandardModel/a6f/include/ilc_fragment_call.f90 and
ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/StandardModel/a6f/include/calc_a1sq_a2sq.f90 ).
h2. Kinematic Cuts
Kinematic cuts are applied to massless particle configurations where some cutoff is required to avoid an infinite cross section. In the WHIZARD event generation stage we set the masses of all first and second generation fermions to zero, so that photons, gluons, electrons, muons and u,d,s,c quarks are all subject to kinematic cuts. The cuts are given by the WHIZARD input parameters _default_jet_cut_, _default_mass_cut_ and _default_q_cut_ . We use the WHIZARD default value
_default_jet_cut_=10 GeV for the minimum invariant mass of a pair of colored particles. We use _default_mass_cut_=4 GeV for the minimum invariant mass of a pair of colorless particles, and we use _default_q_cut_=4 GeV for the minimum sqrt(-Q**2) for
massless t-channel processes.
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_ .
h2. Derived stdhep files.
There are over 3500 files in [ftp://ftp-lcd.slac.stanford.edu/ilc2/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/ilc2/whizdata/ILC500/] and corresponds to a particular subset of final states with a particular initial state electron and positron polarization
combination (such as \-80% electron and \+30% positron).
h3. 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.
h3. 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 the [IDRUPLH variable|#idruplh] in the introduction above.)
h3. Derived stdhep files with randomized final states.
{anchor:derivedfiles}
The following table lists Derived Stdhep files that have been produced. The Raw Stdhep information corresponds to the original stdhep files, each with onea specificsingle final state and 100% initial state polarization.
||Derived Stdhep Files|| Raw Stdhep Files|| Ecm(GeV) || mHiggs (GeV) ||Processes|| Event Weight Lumi (fb-1) || Pol. (%{latex}$\mathbf{ e^-}${latex} / %{latex}$\mathbf{e^+} ${latex}) ||Derived Nevents ||
|[directory|ftp://ftp-lcd.slac.stanford.edu/ilc2/ILC500/LOI_SM_Sample/stdhep/]| - | 500 | 2000 |All 0,2,4,6 fermion SM processes| 250\\250| -80/+30\\+80/-30 |4,737,499\\2,453,865|
|[directory|ftp://ftp-lcd.slac.stanford.edu/ilc/ILC250/Large_Stdhep_SM/]| - | 250 | 2000 |All 0,2,4,6 fermion SM processes| 125\\125 | -80/+30\\+80/-30| 163,155,055 \\ 157,463,964 |
|[directory|ftp://ftp-lcd.slac.stanford.edu/ilc2/ILC250/Run1_Stdhep_Higgs/]| - | 250 | 120 |ffH | 125\\125 | -80/+30\\+80/-30| 39893\\25677|
|[directory|ftp://ftp-lcd.slac.stanford.edu/ilc2/ILC250/Run2_Stdhep_Higgs/]| - | 250 | 120 |ffH | 125\\125 | -80/+30\\+80/-30 | 39893\\25677|
|[directory|ftp://ftp-lcd.slac.stanford.edu/ilc2/ILC250/Run3_Stdhep_Higgs/]| - | 250 | 120 |ffH | 125\\125 | -80/+30\\+80/-30 | 39893\\25677|
|[directory|ftp://ftp-lcd.slac.stanford.edu/ilc2/ILC250/Run4_Stdhep_Higgs/]| - | 250 | 120 |ffH | 125\\125 | -80/+30\\+80/-30 | 39893\\25677|
|[directory|ftp://ftp-lcd.slac.stanford.edu/ilc2/ILC250/ffe2e2_mh120p0/]| - | 250 | 120 |ffH, H--> e2E2 | 125\\125 | -80/+30\\+80/-30 | 61191\\39401|
|[directory|ftp://ftp-lcd.slac.stanford.edu/ilc3/whizdata/ilc_data3/ILC250/e1e1_higgs_recoil/] | [directory|ftp://ftp-lcd.slac.stanford.edu/ilc3/whizdata/ILC250] [index|ftp://ftp-lcd.slac.stanford.edu/ilc3/whizdata/ILC250/doc/integ_index_0250_e1e1_higgs_recoil_01] [logs|ftp://ftp-lcd.slac.stanford.edu/ilc3/whizdata/ILC250/doc/run_output/] | 250 | 2000 |e1E1, 60<Mee<115 GeV, etc. | 125\\125 | -80/+30\\+80/-30 | 1206185\\966087|
|[directory|ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/Xmumu_Xtautau/] | - | 500 | 2000 |e2E2+missing, e3E3+missing | 250\\250 |-80/+30\\+80/-30 | 81,310,104\\80,704,368|
|[directory|ftp://ftp-lcd.slac.stanford.edu/ilc2/ILC500/LOI_desy_tautau/stdhep/]| - | 500 | 2000|e3E3, DESY, correct tau pol.| 250\\250 | -80/+30\\+80/-30 | 1,148,162\\1,010,385|
|[directory|ftp://ftp-lcd.slac.stanford.edu/ilc2/ILC500/LOI_tautau/stdhep/]| - | 500 | 2000|e3E3 | 2000\\2000 |-80/+30\\+80/-30 | 1,443,280\\1,186,634|
|[directory|ftp://ftp-lcd.slac.stanford.edu/ilc2/ILC500/LOI_sixfermion/mtop173.5/stdhep/]| - | 500 | 2000|six fermions from tT | 250\\250 |-80/+30\\+80/-30 | 741,725\\344,362|
|[directory|ftp://ftp-lcd.slac.stanford.edu/ilc2/ILC500/LOI_sixfermion/mtop174.0/stdhep/]| - | 500 | 2000|six fermions from tT | 250\\250 |-80/+30\\+80/-30|757,724\\351,861|
|[directory|ftp://ftp-lcd.slac.stanford.edu/ilc3/whizdata/ilc_data3/ILC500/ffhh_mh120p0/] | [directory|ftp://ftp-lcd.slac.stanford.edu/ilc3/whizdata/ILC500] [index|ftp://ftp-lcd.slac.stanford.edu/ilc3/whizdata/ILC500/doc/integ_index_0500_fhhh_1p00_qcd_01] [logs|ftp://ftp-lcd.slac.stanford.edu/ilc3/whizdata/ILC500/doc/run_output/] | 500 | 120 |ffHH gHHHH=1 | 1000\\1000 | -80/+30\\+80/-30 | 116486\\76540|
The lumi values in this table refer to the event weight normalization, and may not correspond in some instances to the ratio of the number of events to the cross section. Each Derived Stdhep
File directory contains files inv_ab_stdhep_files_XXX_ecmEEE_80L_30R and inv_ab_stdhep_files_XXX_ecmEEE_80R_30L which describe the raw stdhep files used to build the derived files (for example [ftp://ftp-lcd.slac.stanford.edu/ilc/ILC250/Large_Stdhep_SM/inv_ab_stdhep_files_Large_Stdhep_SM_ecm250_80L_30R]).
The fields in the ..._inv_ab_stdhep_files are:
||filename (at SLAC)|| || Begin event || || End event || || Event weight || ||process_id || || 1st initial particle polarization if particle is e\- or e\+; beams/brems flag if photon || || 2nd initial particle polarization if particle is e\- or e\+; beams/brems flag if photon ||
h3. Defining your own derived stdhep files.
You can build your own derived stdhep files by filling out an input card file, such as [ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/StandardModel/aa_bb_example_whizdata.in] or [ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/StandardModel/qqlv_example_whizdata.in] . Comment lines begin with an exclamation point. The fields are:
||_Variable x_|| ||Range of x|| ||_Description/Comment_||
|luminosity| | 0 < x | |Requested luminosity will affect the event weight and in some cases the total number of events read out|
|n_events_max| | 0 < x | |Maximum number of events to be read out, summed over all final states|
|r_read_begin| | 0<= x <= 1| |Point in file where readout begins, in units of the file's length; used to produce independent event samples |
| r_read_end| | 0<= r_read_begin < x <=1 | | Point in file where readout ends, in units of the file's length |
| pol_eminus| | -1 <= x <= 1 | |Electron polarization|
| pol_eplus| |-1 <= x <= 1 | |Positron polarization|
| bremsstr_eminus| | 0<= x <= 1 | |Scale Weizsacker-Williams photon flux from electrons by this number|
| bremsstr_eplus| | 0<= x <= 1 | |Scale Weizsacker-Williams photon flux from positrons by this number|
| beamstr_eminus| | 0<= x <= 1 | |Scale beamstrahlung photon flux from electrons by this number|
| beamstr_eplus| | 0<= x <= 1 | |Scale beamstrahlung photon flux from positrons by this number|
| process| | List of character strings| | List of processes, where a process is specified by an initial state and a final state; CompHEP notation is extended with the symbols q,l,v,f,x|
||_Extended CompHEP Symbol_|| ||Definition|| ||Comment||
|q| |u, d, s, c, b, U, D, S, C, or B| | |
|l| |e1, e2, e3, E1, E2, or E3| | |
|v| |n1, n2, n3, N1, N2, or N3| | |
|f| |q, l, or v| | |
|x| |f, t, A, or H| | |
|e1| |e1 or E1 | | similar definitions hold for all other lower case fermions symbols u,d,s,c,b,e2,e3,n1,n2,n3|
|E1| |E1 | |i.e., the upper case fermion symbols have the same meaning as in CompHEP |
If you want your own derived file please fill in your version of a whizdata.in file and email to [mailto:timb@slac.stanford.edu] . At a minimum we will return a text file containing a list of the stdhep files to be read out. If there is sufficient ftp space we will also produce the derived file. Examples of the readout text files for the whizdata.in sample files mentioned above can be found at [ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/StandardModel/aa_bb_example_inv_ab_stdhep_files] and
[ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/StandardModel/qqlv_example_inv_ab_stdhep_files] .
h2. FAQ
_Whizard 1.40 has no gluon emission by default, leading to potentially incorrect multiplicity distributions._
The WHIZARD version 1.40 that was used to generate this sample indeed did not include gluon emission. However gluon radiation was simulated using PYTHIA's parton showering algorithm. WHIZARD versions 1.50 and higher include gluon emission, and, starting with version 1.91, WHIZARD has its own parton showering code.
_Whizard 1.40 has an incorrect implementation of the CKM matrix. Only diagonal terms of the matrix are present (and = 1!), giving wrong W decays._
Although true for the Whizard version 1.40 that was used to generate this data sample, it is extremely doubtful that this will have any effect on the current analyses. WHIZARD versions 1.51 and higher include the correct CKM matrix, and so future data samples will include the rarer W decays.
_This sample has generator level cuts a la SiD, providing a potential bias when used for ILD._
There are, indeed, some kinematical cuts for processes with divergent cross-sections, which can be seen by looking at the whizard.in file as described above. However, the only kinematic cut that leads to a genuine loss of events is a 4 GeV minimum invariant mass cut on final state fermion-antifermion pairs.
h1. Beam-Beam Background Stdhep Files
Beam-beam backgrounds are extremely large cross-section process such as AA \-\-> e1E1, AA\-\-> e2E2, and AA\-\-> hadrons where the AA center-of-mass energy goes all the way down to threshold. The photons can be either beamstrahlung or Weiszacker-Williams. All Beam-Beam background Stdhep files are unweighted.
||Stdhep File|| Ecm(GeV) ||Process|| Cross-section (fb) ||Nevents ||
|[ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/backgrounds/gghad/stdhep/whizard/w15786_01.stdhep]| 500 |AA\-\->hadrons | 4.61E08 | 241,232 |
|[ftp://ftp-lcd.slac.stanford.edu/ilc/ILC500/backgrounds/ggmumu/stdhep/whizard/w17395_01.stdhep]| 500 |AA\-\->e2E2, pT>115 MeV | 1.36E09 | 433,931 |
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