Charged Higgs tb MC samples

Location of ROOT files

The ROOT files can be downloaded using the following link:

https://cernbox.cern.ch/index.php/s/vzD9i7tCfBFJoOy

Password: cms-buap2016

Background samples

TT

SingleT

W+Jets

DY

ZZ

WW

Signal samples

Merge several ROOT files

Reading Nero Files

In this section you can find the instructions for reading Nero files and create your own code to analyze the samples.

Prerequisites

• Linux/Unix operating system
• ROOT is installed in your computer

Instructions

In this tutorial we will create a program that reads the samples, plots different observables and reconstructs the W boson mass by assuming that it decays into a lepton and the corresponding neutrino.

Once you have downloaded the samples, do the following:

• Open a terminal, change to your working directory (i. e. work) where you will place the program and create two new directories:

cd ~/work
mkdir bin
mkdir lib

• Create a new makefile. This file is used to read the code, compile it and then produce an executable. You can download it by clicking here.
• Then, create a new C++ file using your favorite text editor and introduce the following code. Save the file under the name of nero-reader.cpp.
• Compile and run the code by typing in the terminal:

make
./nero-reader

The file histos.root will be produced. The information of all events (there is no selection) is plotted in the histograms.

If you want to apply a selection on the events, you can run the following code. Here only the events with one lepton with pt > 40 GeV and || < 2.5 and MET with pt > 40 GeV are used to fill the histogram of the W mass. In order to run it, change nero-reader : nero-reader.o (line 40) in the makefile by nero-analyzer : nero-analyzer.o. Compile and run it.

Normalization

For the normalization to 1: In this step, the only thing you have to do is to define the scale as 1.0 / (# of events), and introduce it in your plots. The scale will be different for each sample, because each one has different number of events.

For the normalization to the cross section: In this step, you have to define the scale as follows:

• Multiply the corresponding cross section of your samples (signal and background) by the luminosity. You could consider the value of the latter as 19.7 fb^-1 (inverse femtobarns). This will give you the number of events. Be careful because the cross section is given in picobarns, so you should convert either the luminosity to pb^-1 or the cross section to fb.
• Then, divide by the total number of events.

In this way,

where: is the luminosity, is the cross section and N is the total number of events.

Important dates

Links of interest

• XIV Concurso Leamos La Ciencia Para Todos 2015-2016: http://www.lacienciaparatodos.mx/concurso.aspx
• LIX Congreso Nacional de Física 2016: http://cnf.smf.mx/