SMEFTsim_tutorial_June23

Basic SMEFTsim tutorial for a PhD course.

Prerequisites

you will need:

• Madgraph >=2.6.x
• pyROOT for python2

Tutorial instructions

Setup

download material cloning this repository and move to this folder

https://github.com/IlariaBrivio/SMEFTsim_tutorial_June23.git
cd Material

Running MG and looking at diagrams

launch MadGraph

./MGDIR/bin/mg5_aMC

inside the MadGraph terminal, run

import model ./SMEFTsim_U35_MwScheme_UFO-massless_Hvlvl

SM process:

generate h > e- ve~ mu+ vm SMHLOOP=0 NP=0 NPprop=0
display diagrams
output Hvlvl_SM

pure SMEFT process (quadratics):

generate h > e- ve~ mu+ vm SMHLOOP=0 NP==1 NPprop=0
display diagrams
output Hvlvl_SMEFT

check diagrams operator by operator (without exporting)

generate h > e- ve~ mu+ vm SMHLOOP=0 NP==1 NPcll1==1 NPprop=0
display diagrams
generate h > e- ve~ mu+ vm SMHLOOP=0 NP==1 NPcHl3==1 NPprop=0
display diagrams
generate h > e- ve~ mu+ vm SMHLOOP=0 NP==1 NPcHW==1 NPprop=0
display diagrams
generate h > e- ve~ mu+ vm SMHLOOP=0 NP==1 NPcHbox==1 NPprop=0

SM-SMEFT interference:

generate h > e- ve~ mu+ vm SMHLOOP=0 NP=1 NP^2==1 NPprop=0
output Hvlvl_SMEFT_linear

SM-SMEFT interference, propagator corrections:

generate h > e- ve~ mu+ vm SMHLOOP=0 NP=0 NPprop=2 NPprop^2==2
display diagrams
output Hvlvl_SMEFT_prop

Direct event simulation

• exit MG. in the main shell, copy the predefined cards in the folders just generated

cp param_card_Hvlvl.dat Hvlvl_SM/Cards/param_card.dat
cp param_card_Hvlvl.dat Hvlvl_SMEFT/Cards/param_card.dat
cp param_card_Hvlvl.dat Hvlvl_SMEFT_linear/Cards/param_card.dat
cp param_card_Hvlvl.dat Hvlvl_SMEFT_prop/Cards/param_card.dat

cp run_card_Hvlvl.dat Hvlvl_SM/Cards/run_card.dat
cp run_card_Hvlvl.dat Hvlvl_SMEFT/Cards/run_card.dat
cp run_card_Hvlvl.dat Hvlvl_SMEFT_linear/Cards/run_card.dat
cp run_card_Hvlvl.dat Hvlvl_SMEFT_prop/Cards/run_card.dat

• launch the SM event generation

./Hvlvl_SM/bin/generate_events

when prompted, remove all optional tools (shower, delphes, analysis etc) leave default param and run cards

• launch the generation for quadratic terms. We will check only the operator cHl3

./Hvlvl_SMEFT/bin/generate_events

when prompted, remove all optional tools (shower, delphes, analysis etc) modify param_card setting cHl3=1

• launch the generation for interference terms.

./Hvlvl_SMEFT_linear/bin/generate_events

when prompted, remove all optional tools (shower, delphes, analysis etc) modify param_card setting cHl3=1

• launch the generation for propagator corrections

./Hvlvl_SMEFT_prop/bin/generate_events

when prompted, remove all optional tools (shower, delphes, analysis etc) modify param_card setting cHl3=1

Simulation via reweighting of the SM sample

reweight cards and a script to run them are provided in the material folder. if needed, change the name of the SM directory or run in the launch_reweighting.sh script and then launch it

./launch_reweighting.sh

when prompted, leave all reweight cards unchanged

Event analysis and plotting

run

./make_rootfiles.sh

to run automatically lhe_analyzer.py over all the generated lhe files. This produces a root file for each generation, that contains 4 histograms, corresponding to differential distributions of $m_{e\mu}$, $m_{\mu\nu_\mu}$, $p_T^{l_1}$ (leading lepton), $p_T^\mu$

The make_rootfiles.sh script assumes that the directories are named as in the previous steps, and stores root files in a directory called Root_files. Modify it if needed.

• for the direct generations, check out the histogram shapes from ROOT, eg.

  root
  new TBrowser()
  

• for the reweighted samples, create pdf plots for each distributions by running

  python plot_histos.py Root_files/Hvlvl_SM_run_01.root
  

  modifying the script plot_histos.py it is possible to select which EFT contributions to plot and to adjust the plot ranges.