Private DarkSUSY MC in MG5

Note: The model implementation is now in the model database in FeynRules. Make sure to cite the reference before use in public.

Create a directory and upload the package to the directory

mkdir ~/MadGraph5
cd ~/MadGraph5
#cp /afs/cern.ch/cms/generators/www/MG5_aMC_v2.6.1.tar.gz ./
#v2.4.2 is used in 2017 central MC
cp /afs/cern.ch/cms/generators/www/MG5_aMC_v2.4.2.tar.gz ./
#tar -xzf MG5_aMC_v2.6.1.tar.gz
tar -xzf MG5_aMC_v2.4.2.tar.gz

Get UFO model

Go to the folder MG5_aMC_vXXX/models. Copy the UFO model there and unzip it to folder MSSMD_UFO:

wget --no-check-certificate https://github.com/weishi10141993/DarkSUSY_MC_MG5/raw/master/MSSMDarkSector/MSSMD_UFO.tar.gz
tar xavf MSSMD_UFO.tar.gz

Go to the folder MSSMD_UFO and do:

python write_param_card.py

A param_card.dat will be generated. This will be used later for the decay in madspin_card.dat. You can manually change the mass of dark photon (3000022, MAD, default is 0.25 GeV), lightest neutalino (1000022, Mneu1, default is 10 GeV) and dark neutralino (3000001, MneuD, default is 1 GeV) in this param_card.dat.

Set up ggH processes

Remove the default proc_card.dat in the MG5_aMC_vXXX directory and copy the following proc_card.dat there:

wget https://raw.githubusercontent.com/weishi10141993/DarkSUSY_MC_MG5/master/MSSMDarkSector/proc_card.dat

Run ./bin/mg5_aMC proc_card.dat and a folder called MSSMD will be generated.

Generate and decay particles

cd /MadGraph5/MG5_aMC_vXXX/MSSMD/Cards

Copy the madspin card to the Cards directory:

wget https://raw.githubusercontent.com/weishi10141993/DarkSUSY_MC_MG5/master/MSSMDarkSector/madspin_card.dat

Then go back to MSSMD folder and generate the events:

cd ..
./bin/generate_events

Check the prompt shows madspin = ON and the madspin_card.dat is same as the one you just copied.

Also you have the option to edit run_card.dat to change run settings, such as number of events, center of mass enegry, etc.

After you finish editing and saving the card, the event generation starts. (Note: it takes ~1hr to load the UFO model, so be patient. Current model implementation is built on MSSM model implementation. So it contains a ton of MSSM model parameters. If want to save time, further improvement could be done by slimming the model to only contain relevant particles of the analysis.)

A lhe.gz file will be generated under MG5_aMC_vXXX/MSSMD/Events/run_01_decayed_1 directory. Unzip the file to get the .lhe file:

gunzip -d *.lhe.gz

Change dark photon lifetime

wget https://raw.githubusercontent.com/weishi10141993/DarkSUSY_MC_MG5/master/MSSMDarkSector/replace_lifetime_in_LHE.py

The lifetime can be changed in line 8 (default is 100 mm): ctau_mean_mm = 100

python replace_lifetime_in_LHE.py > DarkSUSY_mH_125_mN1_10_mND_1_mGammaD_0p25_13TeV_cT_100_events80k.lhe

LHE Validation [Optional]

The validation is a simple check of different distributions for the analysis.

wget https://raw.githubusercontent.com/weishi10141993/DarkSUSY_MC_MG5/master/MSSMDarkSector/LHE_read.py
wget https://raw.githubusercontent.com/weishi10141993/DarkSUSY_MC_MG5/master/MSSMDarkSector/tdrStyle.py
python LHE_read.py