Calculation of Mass for Leading Jets in an Event

ROOT
1

I am currently doing a project on jet physics from Higgs decays and struggling to learn the necessary programming. As a starting point I have a sample decay with the relevant parameters/cards/etc in place: I need to run this sample and then

At the moment I have a sample with the relevant parameters/cards in place etc. I can run the event and produce an n-tuple from it, but I need calculate the invariant mass of the two leading p_t jets, as well as delta eta and delta phi and print off the results. Could you give some guidance or advice on how I would calculate this as I have literally no idea how to do this.

If this is not the correct forum could someone point me in the right direction: I feel like this is a ROOT issue as there should be something on ROOT to allow me to do this (maybe if there are specific forums for MadGraph5/Pythia/Delphes that would be more helpful).

2

Do you know how to extract the 4-momenta (as TLorentzVectors) of the jets from your NTuple?

Once you’ve done this, you just sort by descending pT, take the first two 4-vectors and calculate the quantities you need.

3

Ah right, no I’ve not done that before. I have a tuple produced as a result of running the toy decay ie. I ran the process and it created a LINUX directory with items in it called ‘Kinematic Test’ (along those lines), one of the items inside is a ROOT file. This file should contain generated histograms for masses of the jets, pseudorapidity, azimuthal angles and other quantities as mentioned. Could you explain how I would extract the jet 4-momenta out the file and then sort them in order?

I think the calculations need to be done via code as my supervisor has asked me to print the results.