Basic objects challenge

Overview

Teaching: 0 min
Exercises: 45 min

Questions

• How should I construct selection criteria for a physics analysis?

Objectives

• Combine trigger, identification, and isolation information into a full selection for a specific physics process.

All of the trigger and physics object information from this lesson is combined when designing the event selection procedure for a physics analysis.

Workshop analysis example: H -> tau tau

Later in the workshopw we will use a search for Higgs bosons as an example analysis. The signal for this search is one Higgs boson that decays to two tau leptons, with one tau lepton decaying hadronically and the other tau lepton decaying to a muon and neutrinos.

Your analysis example

What is a physics process that you might study? Let’s design a possible CMS event selection. If your process includes a particle with multiple possible decay modes, choose one (or a small group of very similar decay modes) as a test case for this challenge.

For the Higgs search and/or your own process of interest, use the information you have gained about triggers and physics objects to sketch out a possible event selection for your analysis.

Signal

Which final state particles would you expect to observe in the detector from your “signal” process?

Based on these particles, consider:

• Which trigger or triggers would be useful to make sure your signal events are represented in the dataset?
• Which objects should you require in each event?
• What kinematic criteria might you requier for each object? (momentum, angular regions, etc)
• What quality criteria might you require for each object? (identification, isolation)
• Are there any correlations between your objects that you might exploit?

Background

Which SM backgrounds could easily mimic your signal, given a few extra physics objects, or a few missing physics objects?

Based on these processes, consider:

• Which background simulations should you include in your study?
• Should you apply any upper or lower limits on the numbers of certain physics objects in your events?
• Are there any objects you should veto from your events?
• What quality criteria might you choose for vetoing objects?

Solutions

In the final session for this lesson we will go over the actual analysis choices for H -> tau tau and discuss approaches for some physics processes you chose for this challenge.

Key Points

• Come back for the solutions session tomorrow!