Morag Williams: MSci Project Wiki

Project Title: Sensitivity to beyond Standard Model physics through Higgs production at CLIC using effective field theories. Supervisor: Aidan Robson.

In Progress.

MADGRAPH Generating Steps

All using MADGRAPH 2.4.3, which requires Python 2.6 or 2.7. Using the Higgs Effective Lagrangian (HEL) Universal FeynRules Output (UFO) model which can be found here: https://feynrules.irmp.ucl.ac.be/wiki/HEL.

1) Start MADGRAPH:

cd MG5_aMC_v2_4_3/bin/

./mg5_aMC

This opens the MADGRAPH5_ aMC @ NLO interface.

2) Import the HEL_UFO model (which needs to have been copied to your models directory):

import model HEL_UFO

3) Generate electron + positron -> Higgs + electron + positron events, with a new physics parameter and QED type stated.

generate e+ e- > h e+ e- QED=4 NP=1

^^ Note: the order of e+ and e- here defines the incoming beam directions; do this ordering for a +ve positron pseudorapidity.

4) Write to output directory of name ee_hee2

output ee_hee2

quit

5) Travel to the new directory /bin/ee_hee2 and change the run card parameters as needed in file Cards/run_card.dat.

6) Start the MadEvent interface and generate events with the run card parameters specified in run_card.dat.

cd /ee_hee2/bin/

./madevent

generate_events

This will open a web page showing the generation progress and main parameters (such as the particle interaction and beam energies), and create an output file unweighted_events.lhe.gz in Events/run_01. A file run_01_tag_1_banner.txt is also created in /Events/run_01 listing all commands used in the MADGRAPH and MadEvent interfaces and all run card parameters used.

ETA Graphs for different EFT parameters

The default value for the coefficients is 0.1.

Graph of the positron pseudorapidity for two values of cHW: the blue line is for cHW=0.05, the red line is cHW=0.1. 10,00 events were used and the cross sections were 1.36828 pb and 1.63987 pb respectively (to 6 significant figures).

pseudorap_ep_comparisoncHW_0.05_0.1.pdf

Graph of the electron pseudorapidity for two values of cHW: blue line is 0.05, the red line is 0.1. 10,00 events were used and the cross sections were 1.36828 pb and 1.63987 pb respectively (to 6 significant figures).

pseudorap_em_comparisoncHW_0.05_0.1.pdf

Graph of the positron pseudorapidity for three values of cWW: the blue line is for cWW=0.05, the red line is cWW=0.1, and the green line is cWW=0.075. 10,00 events were used and the cross sections were 1.31255 pb, 1.46576 pb, and 1.63987 pb respectively (to 6 significant figures).

pseudorap_ep_comparisoncWW_0.05_0.1_0.075.pdf

Graph of the electron pseudorapidity for three values of cWW: the blue line is for cWW=0.05, the green line is cWW=0.075, and the red line is cWW=0.1. 10,00 events were used and the cross sections were 1.31255 pb, 1.46576 pb and 1.63987 pb respectively (to 6 significant figures).

pseudorap_em_comparisoncWW_0.05_0.1_0.075.pdf

-- Morag Williams - 2016-11-07

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