• ATLAS publication (June 2022, full Run-2 dataset) Measurement of Higgs boson decay into b-quarks in associated production with a top-quark pair in pp collisions at √s = 13 TeV with the ATLAS detector

• Direct observation of the interaction between the Higgs boson and top quark announced by experiments at CERN: RHUL press release

• CMS publication (13 TeV; 2015+16 data only): Search for ttH production in the H→bb decay channel with leptonic tt decays in proton-proton collisions at 13 TeV

• ATLAS conference note (13 TeV; full Run-2 dataset): Measurement of the Higgs boson decaying to b-quarks produced in association with a top-quark pair in pp collisions at 13 TeV (ATLAS-CONF-2020-058, Oct.2020)

• ATLAS-CONF-2020-058_rel_29_Oct_2020.pdf: ATLAS-CONF-2020-058_rel_29_Oct_2020.pdf

myplots_display_PH4100_v2.2.C 

Editing files (using the emacs or vi editors)

How to connect to the linappserv linux computer cluster from your laptop or from a PC in the Teaching Lab

 run_analysis_PH4100.C
 analysis_ttH_PH4100_v3.0-FOR-STUDENT.C
 analysis_ttH_PH4100.h
 functions/prot_makeCutFlowTables.C
 functions/func_makeCutFlowTables-PH4100mod.C
 functions/prot_identifyProcess_082019Prod.C
 functions/func_identifyProcess_082019Prod.C

-- Pedro Teixeira Dias - 20 Jan 2021

• • eg see here for: pointers

(Information on an older list of simulated samples is still available in this page, just for reference.)

Analysis framework and workflow

The following diagram is a schematic depiction of the basic framework and work flow for the analysis.

The student will be given access to all the required simulated data samples as well as template code files (eg analysis_ttH_PH4100.C and myplots_display_PH4100.C) to start with. The latter will need to be added to by the student, as they develop their own data analysis.

-- Pedro Teixeira Dias - 04 Nov 2019

Physics: important sources of information

• ATLAS publication (13 TeV; 2015+16 data only): Search for the standard model Higgs boson produced in association with top quarks and decaying into a bb pair in pp collisions at 13 TeV with the ATLAS detector

Tools for the project

This is a computer-based project. You will be analysing large simulated samples of events in the ATLAS detector at the LHC. The project requires programming in C++, the use of the ROOT data analysis package and knowledge of basic Linux OS commands. Links to sources of information on these and other topics are given in the sub-topics below.

How to connect to the linappserv computer cluster from your laptop or from a PC in the Teaching Lab

The most up-to-date instructions for this are normally on the web page of the PH4515 Statistical Data Analysis course (taught by Prof. Glen Cowan). The direct link to the instructions is here.

Troubleshooting:

• If connecting at RHUL, it seems that being connected to the CampusNet network (rather than eg eduroam) is important.
• On the Teaching Lab PCs, you may have to download PuTTY if it is not already installed. If that is the case find and download the respective the MS Installer file (*.msi) on the web. After the download is complete the file should auto-install.

Normally it would be expected that students doing this project are taking the PH4515 Statistical Data Analysis course taught by Prof. Glen Cowan.

The Particle Data Group (PDG) website includes a lot of useful information. In particular, the student should use the "Summary Tables" to find out the main decay modes and respective branching ratios for the following particles: top, Higgs, W and Z. The decays of the tau lepton to electrons or muons (as opposed to hadronic decays of the tau lepton) are also of interest for this project.

Links to some useful C++ resources:

• The PH4515 Statistical Data Analysis course includes revision of C++: slides available here.
• The RHUL library has many different books on C++ programming.
• A C++ online reference guide, with tutorials and more: www.cplusplus.com.
• Another C++ online reference guide: cppreference.com.

• The homepage of ROOT at CERN has much useful information, including the User Guide for ROOT 6 in html or as a single pdf file.

• • In this project you will analyse ntuples containing variables defined for each event. In ROOT, ntuples are called "Trees" and the variables are sometimes referred to as the "leafs".
  • See the Chapter "Trees" in the ROOT User Guide for more information, and especially the sub-section "Using TTree::MakeSelector" which describes the TSelector framework that is used in this project.
• Using TLorentz four-vectors: see the Chapter "Physics Vectors", and especially the sub-section that describes four-vectors in ROOT ("TLorentzVectors").

Gnu Emacs editor

handy reference card

Simulated event samples

How to connect to the linappserv computer cluster from your laptop or from a PC in the Teaching Lab

The most up-to-date instructions for this are normally on the web page of the PH4515 Statistical Data Analysis course (taught by Prof. Glen Cowan). The direct link to the instructions is here.

Troubleshooting:

• If connecting at RHUL, it seems that being connected to the CampusNet network (rather than eg eduroam) is important.
• On the Teaching Lab PCs, you may have to download PuTTY if it is not already installed. If that is the case find and download the respective the MS Installer file (*.msi) on the web. After the download is complete the file should auto-install.

• A first look at a signal ntuple: see instructions here.

PH4100 MSci Major Projects - ATLAS ttH (H-bb)

Introduction

This project is based on the analysis of simulated data of proton-proton collisions in the ATLAS particle detector at the Large Hadron Collider (LHC). The objective is to study the production of Higgs particles in association with a pair of top quarks: the so-called ttH process. Specifically the process of interest (the signal) is when the Higgs boson decays to a pair of b quarks: ttH (H-bb). The project will required the detailed analysis of simulated samples of signal events, as well as analysing all the relevant background processes. In particular ,the student will aim to develop event selection procedures to effectively separate the signal from the backgrounds. This will start with the development of a simple cut-based event selection, optimised using relevant metrics. The student can then progress this to using instead an event selection based on eg a Fisher discriminant, or more advanced multivariate methods (such as a Neural Network (NN) or a Boosted Decision Tree (BDT)).

How to connect to the linappserv computer cluster from your laptop or PC in the Teaching Lab

Tools for the project

This is a computer-based project. You will be analysing large simulated samples of events in the ATLAS detector at the LHC. The project requires programming in C++, the use of the ROOT data analysis package and knowledge of basic Linux OS commands. Links to sources of information on these and other topics are given here.

C++ programming language

ROOT data analysis package

• User Guide for ROOT 6
• Using TSelector framework to process ntuples
• Using TLorentz four-vectors

Linux OS

emacs editor

Simulated samples

bla

-- Pedro Teixeira Dias - 21 Oct 2019

Comments

<--/commentPlugin-->