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 effect of varying different Higgs c coupling coefficient values has been investigated. I varied cHW, cWW, and then both simultaneously. The c coefficient values for the SM case are 0. For each comparison there are 3 plots: there is the original unscaled histogram of the pseudorapidity; one scaled to make the y axis d(simga)/d(eta) by using a factor of (crosssection) / (integral under the histogram) on the original histogram; and then one scaled to make the y axis 1/sigma d(simga)/d(eta) by using a factor of 1 / (integral under the histogram) on the original histogram. 100,000 events were generated for each coupling value.

The Standard Model line on each comparison plot had a cross section of 0.028427 pb (to 6 significant figures) and had 99797 entries from the original 100,000 generated. Graphs of the electron pseudorapidity for the SM case.

etacomparison_unscaled_SM_em.pdf: etacomparison_unscaled_SM_em.pdf

etacomparison_scaled_SM_em.pdf: etacomparison_scaled_SM_em.pdf

etacomparison_scaledsigma_SM_em.pdf: etacomparison_scaledsigma_SM_em.pdf

Graphs of the positron pseudorapidity for the SM case.

etacomparison_unscaled_SM_ep.pdf: etacomparison_unscaled_SM_ep.pdf

etacomparison_scaled_SM_ep.pdf: etacomparison_scaled_SM_ep.pdf

etacomparison_scaledsigma_SM_ep.pdf: etacomparison_scaledsigma_SM_ep.pdf

Graphs of the electron pseudorapidity for three values of cHW: 0.1, 0.075, and 0.05. The cross sections were 0.092673, 0.060957, 0.039631 pb respectively (to 6 decimal places). All other coefficients were set at 0.

etacomparison_unscaled_cHW_em.pdf: etacomparison_unscaled_cHW_em.pdf

etacomparison_scaled_cHW_em.pdf: etacomparison_scaled_cHW_em.pdf

etacomparison_scaledsigma_cHW_em.pdf: etacomparison_scaledsigma_cHW_em.pdf

Graph of the positron pseudorapidity for three values of cHW: 0.1, 0.075, and 0.05. The cross sections were 0.092673, 0.060957, 0.039631 pb respectively (to 6 decimal places). All other coefficients were set at 0.

etacomparison_unscaled_cHW_ep.pdf: etacomparison_unscaled_cHW_ep.pdf

etacomparison_scaled_cHW_ep.pdf: etacomparison_scaled_cHW_ep.pdf

etacomparison_scaledsigma_cHW_ep.pdf: etacomparison_scaledsigma_cHW_ep.pdf

Graphs of the electron pseudorapidity for three values of cWW: 0.1, 0.075, and 0.05. The cross sections were 0.110403, 0.070788, 0.044749 pb respectively (to 6 decimal places). All other coefficients were set at 0.

etacomparison_unscaled_cWW_em.pdf: etacomparison_unscaled_cWW_em.pdf

etacomparison_scaled_cWW_em.pdf: etacomparison_scaled_cWW_em.pdf

etacomparison_scaledsigma_cWW_em.pdf: etacomparison_scaledsigma_cWW_em.pdf

Graphs of the positron pseudorapidity for three values of cWW: 0.1, 0.075, and 0.05. The cross sections were 0.110403, 0.070788, 0.044749 pb respectively (to 6 decimal places). All other coefficients were set at 0.

etacomparison_unscaled_cWW_ep.pdf: etacomparison_unscaled_cWW_ep.pdf

etacomparison_scaled_cWW_ep.pdf: etacomparison_scaled_cWW_ep.pdf

etacomparison_scaledsigma_cWW_ep.pdf: etacomparison_scaledsigma_cWW_ep.pdf

Graphs of the electron pseudorapidity for three values of cWW and cHW: both at 0.1, both at 0.075, and both at 0.05. The cross sections were 0.354658, 0.200238, 0.097377 pb respectively (to 6 decimal places). All other coefficients were set at 0.

etacomparison_unscaled_cHWcWW_em.pdf: etacomparison_unscaled_cHWcWW_em.pdf

etacomparison_scaled_cHWcWW_em.pdf: etacomparison_scaled_cHWcWW_em.pdf

etacomparison_scaledsigma_cHWcWW_em.pdf: etacomparison_scaledsigma_cHWcWW_em.pdf

Graphs of the positron pseudorapidity for three values of cWW and cHW: both at 0.1, both at 0.075, and both at 0.05. The cross sections were 0.354658, 0.200238, 0.097377 pb respectively (to 6 decimal places). All other coefficients were set at 0.

etacomparison_unscaled_cHWcWW_ep.pdf: etacomparison_unscaled_cHWcWW_ep.pdf

etacomparison_scaled_cHWcWW_ep.pdf: etacomparison_scaled_cHWcWW_ep.pdf

etacomparison_scaledsigma_cHWcWW_ep.pdf: etacomparison_scaledsigma_cHWcWW_ep.pdf

Analysis Graphs

Pseudorapidity graphs showing the effect of the eta cut (only events with eta_em <2.75 and eta_ep <2.75 used) on different EFT parameters:

• deta_cHW5_etacut.pdf: deta_cHW5_etacut.pdf

• deta_cHW75_etacut.pdf: deta_cHW75_etacut.pdf

• deta_cWW5_etacut.pdf: deta_cWW5_etacut.pdf

• deta_cWW75_etacut.pdf: deta_cWW75_etacut.pdf

• deta_SM_etacut.pdf: deta_SM_etacut.pdf

• deta_bck_etacut.pdf: deta_bck_etacut.pdf

Morag Williams - 2016-11-07

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