%CERTIFY%
Hgg exercise 10 TeV
The purpose of this site is to put in common some information to be used in our Hgg exercise at 10 TeV.
Meetings
Mailing list
http://groups.google.com/group/hgg-atlas-france
SVN repository
https://svnweb.cern.ch/cern/wsvn/hggaf
Hfitter
Link to the Hfitter TWiki
Ntuple production
Signal
Irreducible background (Under Construction)
The irreducible background which corresponds to the production of a pair of
photon mainly comprises of three processes: the Born process (qq -->
gamma gamma), the Box process (gg --> gamma gamma) and the
Bremsstrahlung process (qg --> q[-->q gamma] gamma).
To estimate a Next-to-Leading Order normalization of the irreducible
background at LHC energies, different programs and Monte-Carlo
generators are used. The generators allow for a prediction of
experimental effects (work with reconstructed quantities) while the
programs provide a more careful treatment of QCD corrections. The
MC generators and
programs used in most studies (CSC, prospects for exclusion at 10
and 7 TeV centre-of-mass energies) are respectively
Alpgen and Pythia and
Resbos and Diphox.
Alpgen and Pythia samples used for the study of prospects for
Higgs boson exclusion at 10 TeV (
ATL-COM-PHYS-2010-218) are listed in the following.
The specificities of Resbos and Diphox programs and the method to install and use them are described
below. As an example, the steps to reproduce the plots and results
derived in the 10 TeV study are detailed.
Alpgen and Pythia
The rootfiles used to derive Alpgen and Pythia differential cross sections for the analysis at 10
TeV use these different samples:
Data set |
x-sec (pb) |
Filter Eff. (%) |
N events |
Eq. luminosity (pb-1) |
specificities |
mc08.105964.Pythiagamgam15.merge.AOD.e347_s462_s520_r808_r838 |
9.345 E+2 |
12.81 |
99939 |
8.35 E+2 |
born+box |
mc08.106895.AlpgenJimmyGamGamWithAAMassNp0.merge.AOD.e384_s462_s520_r808_r838 |
4.530 |
100 |
99891 |
2.21 E+4 |
born+brem (0 hard parton) |
mc08.106896.AlpgenJimmyGamGamWithAAMassNp1.merge.AOD.e384_s462_s520_r808_r838 |
3.860 |
100 |
85951 |
2.23 E+4 |
born+brem (1 hard parton) |
mc08.106897.AlpgenJimmyGamGamWithAAMassNp2.merge.AOD.e384_s462_s520_r808_r838 |
2.800 |
100 |
99892 |
3.57 E+4 |
born+brem (2 hard partons) |
mc08.106898.AlpgenJimmyGamGamWithAAMassNp3.merge.AOD.e384_s462_s520_r808_r838 |
2.080 |
100 |
99906 |
4.80 E+4 |
born+brem (3 hard partons) |
The rootfiles are produced using the PAU package (Version 96) and can be found at Lyon:
> ls /sps/atlas/h/hggaf/PAU-96/
group09.PhotonAnalysis.mc08.105964.Pythiagamgam15.merge.AOD.e347_s462_s520_r808_r838.NTUP.rel1561.PAU-00-00-96.v0
group09.PhotonAnalysis.mc08.106895.AlpgenJimmyGamGamWithAAMassNp0.merge.AOD.e384_s462_s520_r808_r838.NTUP.rel1561.PAU-00-00-96.v0
group09.PhotonAnalysis.mc08.106896.AlpgenJimmyGamGamWithAAMassNp1.merge.AOD.e384_s462_s520_r808_r838.NTUP.rel1561.PAU-00-00-96.v0
group09.PhotonAnalysis.mc08.106897.AlpgenJimmyGamGamWithAAMassNp2.merge.AOD.e384_s462_s520_r808_r838.NTUP.rel1561.PAU-00-00-96.v0
group09.PhotonAnalysis.mc08.106898.AlpgenJimmyGamGamWithAAMassNp3.merge.AOD.e384_s462_s520_r808_r838.NTUP.rel1561.PAU-00-00-96.v0
The rootfile are then reduced using a macro
reducePAU.C. The header is
reducePAU.h
One should note that for Alpgen, the reduced rootfiles for each exclusive sample (2 photons+ n partons, n=0..3) must be generated before the reweighting (in the purpose of defining the weight) and after reweighting to get the final differential cross sections for the born+brem contribution. The weight defined per bin of 2.5 GeV/c in diphoton transverse momentum and used in the 10
TeV analysis can be found
here .
Resbos
Resbos is a program of resummed NLO Martix Element
(ME) calculation. It produces differential cross sections of the
diphoton production in high energy experiments, such as the Tevatron
and the LHC. It implements the Born and Box processes, and also the Brem process, with the emission of a photon by
a final-state parton. The NLO QCD corrections and the soft gluons
initial-state resummed corrections are included.
To absorb the IR and colinear final-state divergences arising in the
Brem process, the LO one photon fragmentation of a final-state parton
is included. To describe the experimental effects Resbos implements a
pseudo-experimental isolation, requiring that the tranverse energy
deposited in a cone in the (eta,phi) plane around the photon direction
does not exceed a threshold fixed by the user, as well as the cone
size. Typical values are Et_max = 15 GeV and DeltaR = 0.4. A
separation between the two photons is also required (typically
DeltaR_gammagamma = 0.7).
A short description of Resbos
followed by a complete bibliograhy is available on
ResBos page.
Resbos package
The Resbos code is made in fortran. The package can be downloaded
here.
It contains:
- book_ntuple_lhc_public.bat which is the executable. It uses input files and grids. It produces ntuples (in Root or Paw format) and output files with details of the calculation.
- ins/: the directory containing the input files in the subdirectory lhc/. The differential and total resummed cross sections for the born and brem processes are generated simultaneously and separately from the box process. "aa" symbolizes the born+brem contribution and "ag" the box. The program calculates two different parts of the phase space that are the perturbative part, symbolyzed by "ps2" and which occurs at medium to high Pt_gammagamma, and the resummed part, symbolzyed by "w2211" and which provides the smooth shape at low Pt_gammagamma. The parameters in the input files are used in book_ntuple_lhc_public.bat , which is very intuitive.
- grids/: the directory contains the LHC input grids for the irreducible background at 10 TeV energy in the centre-of-mass. The grids for the irreducible background production at other energies at LHC (7, 14 TeV) are available at the link: http://hep.pa.msu.edu/resum/grids/resbos_p/aa/lhc/
- input/: contains the files for the PDFs. By default the NLO PDF cteq6m is used. Other PDFs can be found at the link: http://hep.pa.msu.edu/resum/index.html#AA (one should probably ask for the corresponding grids to the author of the code: Pavel Nadolsky <nadolsky@physics.smu.edu>)
- The principal directory also contains the fortran code resbos.f and a Makefile, needed for the first compilation. A detailed readme and a report of resbos updates can be found in the file resbos.f. Only root ntuples are created with this version of Resbos (For Paw ntuples, you need another version, probably older).
How to install?
1.- Resbos is a 32bit program. Check that you are in 32bit machine. For instance at Lyon (username_at_ccalisl5.in2p3.fr):
> file /usr/bin/file
/usr/bin/file: ELF 64-bit LSB executable, AMD x86-64, version 1 (SYSV), for GNU/Linux 2.6.9, dynamically linked (uses shared libs), for GNU/Linux 2.6.9, stripped
2.- setup root in 32 bit:
> export ROOTSYS=/afs/cern.ch/atlas/software/releases/15.6.8/sw/lcg/app/releases/ROOT/5.22.00d/i686-slc5-gcc43-opt/root
> export PATH=$ROOTSYS/bin:$PATH
> export LD_LIBRARY_PATH=$ROOTSYS/lib:$LD_LIBRARY_PATH
3.- Use the paw and root libraries in 32bit in the
Makefile:
PAWLIBS=-L/afs/cern.ch/sw/lcg/external/cernlib/2005/x86_64-slc5-gcc34-opt/lib -lpacklib_noshift
ROOTDIR=/afs/cern.ch/atlas/software/releases/15.6.8/sw/lcg/app/releases/ROOT/5.22.00d/i686-slc5-gcc43-opt/root
and in the executable:
export ROOTSYS=/afs/cern.ch/atlas/software/releases/15.6.8/sw/lcg/app/releases/ROOT/5.22.00d/i686-slc5-gcc43-opt/root
export PATH=$ROOTSYS/bin:$PATH
export LD_LIBRARY_PATH=$ROOTSYS/lib:$LD_LIBRARY_PATH
4.- Compile:
> make
5.- Run the program:
> ./book_ntuple_lhc_public.bat
It takes generally less than one hour. Two root ntuples are created: one for the born+brem contribution and one for the box contribution.
6.- If you wish to work with a single root ntuple you can merge the two previous ntuples:
> ./treemerge h10 merge_ntuple_lhc10TeV_ct6m.root res321_aa_lhc10TeV_ct6m.root res321_ag_lhc10TeV_ct6m.root
Then you have one root nutple containing a list of kinematic variables per event defined in the Collin-Soper frame :
D_phi, DelR34, M_B, WT00, cos_the_, pT_d1, pT_d2, phi_sta, y_B, y_d1 and y_d2 .
Diphox
Diphox is a fixed order program of ME
calculation almost fully at NLO (the box process is implemented at LO
only), including the fragmentation into a leading photon of one or two
final-state partons. Its treatment of fragmentation is particularly
accurate. Despite the absence of treatment of the soft emission which
may imply discontinuities in the description of physical observables,
Diphox provides meaningful differential cross sections at NLO. It can be used to derive a NLO normalization of the born+brem processes.
Diphox package can be downloaded
here (or in the link
http://lappweb.in2p3.fr/lapth/PHOX_FAMILY/diphox.html). A detail readme can be found in
the same link. The package structure and the method how to install it and run the
program are described there.
In the spirit to make the user's life easier, one can follow the instructions below to install and run Diphox program:
How to Install?
1.- Uncompress the package:
> tar zxvf diphox_1.2.tar.gz
There are 7 subdirectories in diphox_1.2/ whose contains are descibed in detail in the readme. In the working/ directory, the user essentially cares about two files:
parameter.indat which fixes all the parameters for the generation and
param_histo.indat which fixes the kinematic cuts applied at the
level of the histograms and the number of histograms in the ntuple,
their name and binning.
2.- Before doing the Makefile, the user has to download few more files:
- Download this Makefile and replace the one in working/ by this new one. Few modifications are applied with respect to the original version, that basically ensure the use of the good CERN libraries as well as the use of the PDF cteq61. This new set of PDF is not implemented in the Diphox package by default.
- Download the librairy for cteq61 (uncompress it) and a small program used to identify which PDF is used in the parameters (in parameter.indat). Put the program and the sub-directory in pdfs/
> cp -r cteq6.1/ ~/username/diphox_1.2/pdfs/
> cp pftopdg_cteq61.f ~/username/diphox_1.2/pdfs/
3.- Do the makefile:
> make bases
> make
4.- Run the program:
> perl start.pl
This creates the executable runXXX.exe where XXX is an arbitrary name fixed by the user (_pipo in the parameter.indat by default)
> run_pipo.exe
As the calculation takes a long time (few hours-days), you might want to send jobs in bash (for instance using qsub commands)
The output (containing the rootfiles) is by default located in pawres/ subdirectory. There is one output file produced for each contribution: direct, one fragmentation and two fragmentations contributions separetly, respecteiley symbolized by ggd, ggo, ggt followed by the extension choosen by the user (in parameter.indat). Diphox produces paw histograms. To transform them into root files, simply do:
> h2root ggd.dat the_name_you_wish.root (for the direct contribution)
> h2root ggo.dat the_name_you_wish.root (for the one fragmentation contribution)
> h2root ggt.dat the_name_you_wish.root (for the two fragmentation contribution)
NB : For more complicated change in kinematic cuts go to
/src/histo/histo_selection.f and play with the cuts at the end of the code. For instance to mimics the crack region replace:
rapidite = (y1.le.y1max.and.y1.ge.y1min).and.
# (y2.le.y2max.and.y2.ge.y2min)
by
crack1 = 1.37
crack2 = 1.52
y1abs = sqrt(y1**2)
y2abs = sqrt(y2**2)
rapidite = (y1.le.y1max.and.y1.ge.y1min).and.
# (y2.le.y2max.and.y2.ge.y2min).and.
# (y1abs.le.crack1.or.y1abs.ge.crack2).and.
# (y2abs.le.crack1.or.y2abs.ge.crack2)
Application: reproduce Resbos and Diphox root ntuples used to derive a NLO normalization of the irreducible background at 10 TeV
Normalization of the born+brem contribution:
For Resbos that is used in the reweighting procedure, typical
executable file can be found
here. The kinematic cuts are loose with
respect to the final analysis to unbias the final result. A macro is
needed to produce a rootfile from the initial ntuple. Such macro can
be downloaded
here. It generates a rootfile for the born+brem
contribution only that is then used to derive the Pt binned weight.
As explained in the note
ATL-COM-PHYS-2010-218 Resbos cross section is
corrected by Diphox which implements the one and two
photon-fragmentations at NLO while Resbos only mimics the one
photon-fragmentation at LO. It leads to an increase of the total
born+brem cross section of about 22%. Here are the typical
parameter.indat
and
param_histo.indat Diphox files used in the study.
In Diphox, the cuts must be choosen in the parameter.indat and param_histo.indat files initially, before running the program as the ouput is a already rootfile.
Reproduce Figure 9: comparison Resbos/Diphox
The kinematic cuts used are the standard ones:
Pt_leading > 40
GeV/c, Pt_subleading > 25
GeV/c
100 < M_gammagamma < 150
GeV/c2
|eta_leading, eta_subleading| < 2.37 (+ crack region excluded)
One can find the Resbos and Diphox rootfiles at Lyon respectively at the following paths:
>ls /sps/atlas/h/hggaf/FilesDiphox
ggd_AA_10TeV_100m150_crack2.7_pdfNLO_alphaNLO.root
ggd_AG_10TeV_100m150_crack2.7_pdfNLO_alphaNLO.root
ggd_AG_10TeV_100m150_crack2.7_pdfLO_alphaLO.root
ggo_AA_10TeV_100m150_crack2.7_pdfNLO_alphaNLO.root
ggt_AA_10TeV_100m150_crack2.7_pdfNLO_alphaNLO.root
>ls /sps/atlas/h/hggaf/FilesResBos
data_aa_10TeV_ptmin25_ptmax40_100m150_crack2.37_isub12_DRgg0.7_vPavel0.root
data_ag_10TeV_ptmin25_ptmax40_100m150_crack2.37_isub12_DRgg0.7_vPavel0.root
Once you have Resbos and Diphox rootfiles you can easily reproduce the plots in Figure 9 of the Note using this
macro.
There is of course some esthetic changes to perform in order to get exactely the same style (see Fig9a.gif and Fig9b.gif in attachment)....
Fig 9.a
Fig 9.b
|
Reproduce Figure 10: comparison Alpgen/Resbos, Weight definition
The purpose of this twiki page is not to explain how to produce Alpgen
rootfiles. However as these are used to produce the plots of Figure 10
and 13, rootfiles before reweighting can be found at Lyon :
> ls /sps/atlas/h/hggaf/FilesALPGEN/
dataAlpGen2g0j_PAUcuts_ALLStat_FitTestLargerCut_nodependence.root
dataAlpGen2g2j_PAUcuts_ALLStat_FitTestLargerCut_nodependence.root
dataAlpGen2g1j_PAUcuts_ALLStat_FitTestLargerCut_nodependence.root
dataAlpGen2g3j_PAUcuts_ALLStat_FitTestLargerCut_nodependence.root
The reduced rootfiles (after reweighting, as used in Figure 12) can be found at Lyon at:
> ls /sps/atlas/h/hggaf/Reduced_PAU-96/
reduced_106895.AlpgenJimmyGamGamWithAAMassNp0.root
reduced_106897.AlpgenJimmyGamGamWithAAMassNp2.root
reduced_106896.AlpgenJimmyGamGamWithAAMassNp1.root
reduced_106898.AlpgenJimmyGamGamWithAAMassNp3.root
To reproduce the plot of Figure 10, one can use this
macro. In the macro, the result of the fit on the weight is directly given (the user therefore has to repeat the fit procedure for any other study) and used to fill the file
weights_Alpgen_10TeV_wfit_r838_Pavel_largerNodep.txt that is used to produce the reduced ntuples after reweighting.
Fig 10.a
Fig 10.b
|
Normalization of the box contribution:
The normalization of the Box process is relatively simple. It consists of normalizing Pythia cross section to the NLO cross section as generated with Resbos.
Using the Resbos rootfile for the Box contribution that can be found at:
/sps/atlas/h/hggaf/FilesResBos/
as well as Pythia rootfile located at
/sps/atlas/h/hggaf/FilesPythia/, the user can reproduce the plot of Figure 12 of the note using this
macro.
Fig 12
|
Reproduce Figure 13: Plot of Ptgg and Mgg for all irreducible background
Figure 13 of the Note illustrates the distributions of the transverse momentum and the invariant mass of the diphoton system combining the Born+Brem and Box contributions to the irreducible background. These plots are made using the reduced ntuples of Alpgen after reweighting and of Pythia after applying a k-factor translating the NLO QCD corrections brought by Resbos.
These ntuples used can be found at Lyon:
>ls /sps/atlas/h/hggaf/Reduced_PAU-96
...
reduced_105964.Pythiagamgam15.root
reduced_106895.AlpgenJimmyGamGamWithAAMassNp0.root
reduced_106896.AlpgenJimmyGamGamWithAAMassNp1.root
reduced_106897.AlpgenJimmyGamGamWithAAMassNp2.root
reduced_106898.AlpgenJimmyGamGamWithAAMassNp3.root
...
To reproduce these plots, one can use the following
macro.
The rootfiles used in the macro can be found in
/sps/atlas/h/hggaf/FilesALPGEN/ and
/sps/atlas/h/hggaf/FilesPythia/. (These differ from the previous one in term of normalization).
Fig 13.a
Fig 13.b
|
Reducible background
The jets/event numbers are related to jets in the acceptance (|eta|<1.37 || 1.52<|eta|<2.37) whose highest-pt matching particle within a cone of radius 0.4 is a parton (either gluon or a quark).
Data set |
x-sec (pb) |
Filter Eff. |
Jets/event |
g-jets |
q-jets |
mc08.105802.JF17_pythia_jet_filter |
(1.457+/-0.002) E+9 |
0.0709+/-0.0001 |
0.4412+/-0.0003 (pt>20GeV) |
0.3303+/-0.0003 |
0.1108+/-0.0002 |
0.2167+/-0.0007 (pt>25GeV) |
0.1621+/-0.0002 |
0.0546+/-0.0001 |
0.0353+/-0.0001 (pt>40GeV) |
0.0259+/-0.0001 |
0.0095+/-0.0001 |
mc08.105807.JF35_pythia_jet_filter |
(7.517+/-0.009) E+7 |
0.1356+/-0.0005 |
0.5315+/-0.0010 (pt>40GeV) |
0.3856+/-0.0009 |
0.1459+/-0.0005 |
mc08.105807.JF70_pythia_jet_filter |
4.719E+6 |
0.2002+/-0.0006 |
0.5241+/-0.0011 (pt>80GeV) |
0.3583+/-0.0009 |
0.1659+/-0.0006 |
mc08.105830.JF17_herwig_jet_filter |
1.166E+9 |
0.0827+/-0.0002 |
0.4268+/-0.0005 (pt>20GeV) |
0.3323+/-0.0004 |
0.0945+/-0.0002 |
0.2074+/-0.0003 (pt>25GeV) |
0.1597+/-0.0003 |
0.0477+/-0.0002 |
0.0338+/-0.0001 (pt>40GeV) |
0.0250+/-0.0001 |
0.0088+/-0.0001 |
mc08.105831.JF35_herwig_jet_filter |
6.055E+7 |
0.1444+/-0.0003 |
0.4989+/-0.0005 (pt>40GeV) |
0.3687+/-0.0004 |
0.1302+/-0.0003 |
mc08.105831.JF70_herwig_jet_filter |
3.812E+6 |
0.1970+/-0.0003 |
0.4773+/-0.0006 (pt>80GeV) |
0.3248+/-0.0005 |
0.1525+/-0.0003 |
|
mc08.106379.PythiaPhotonJet_AsymJetFilter |
2.892E+5 |
0.0361+/-0.0002 |
0.3269+/-0.0006 (pt>20GeV) |
0.0629+/-0.0003 |
0.2640+/-0.0005 |
mc08.108086.PythiaPhotonJet_JetFilter_Nj2Et17 |
0.0721+/-0.0003 |
0.1718+/-0.0004 (pt>25GeV) |
0.0294+/-0.0002 |
0.1424+/-0.0004 |
mc08.108087.PythiaPhotonJet_Unbinned17 |
0.4292+/-0.0006 |
0.0365+/-0.0002 (pt>40GeV) |
0.0050+/-0.0001 |
0.0315+/-0.0002 |
Jetphox package
The jetphox package can be downloaded at the link
http://lappweb.in2p3.fr/lapth/PHOX_FAMILY/jetphox.html. However several modifications are needed to be able to produce rootfiles for standard ATLAS analyses as performed in the HSG1 group, to estimate semi-reducible background normalization at Next-to-Leading Order with the account for the NLO photon fragmentation of final-state parton. Few modifications in the code (Fortran language), are
applied in a new package that can be downloded here:
- initially there is no cut such as pt_min = min(pt_gamma,pt_jet), pt_max = max(pt_gamma,pt_jet) in jetphox. To have such cut, the user can modify the file jetphox_1.0/src/histo/histo_selection_jet.f. The best way to do it is to choose losse cuts in parameter.indat (typically pt_gamma > 10 GeV, pt_jet > 20 GeV) and in the histo_selection_jet.f file to define asymetric cuts, as proposed in the new package.
- initially there is no mass definition or cut. Similarly the gamma-jet mass and the mass range can be defined in histo_selection_jet.f. The start.pl file in the working/ direcotry also requires few changes. Finally, the mass histograms are defined param_histo.indat. These modifications are done in the new package.
- As in Diphox, the fiducial cut are not applied in the initial version of jetphox but can be defined in the histo_selection_jet.f file. There are aken into account in the new version proposed here.
To install Jetphox package the user can follow the instructions given for Diphox.
Major updates:
--
HeberthTorres - 29-Nov-2009
--
GiovanniMarchiori - 08-Dec-2009
--
BernatPauline - 04-Aug-2010
%RESPONSIBLE% Main.unknown
%REVIEW%
Never reviewed