wiki:CernSummerSchool16
Last modified 16 months ago Last modified on 07/25/16 15:35:48

2016 CERN Summer student workshop

by Hua-Sheng Shao and Marco Zaro

Exercises : discover the Higgs boson at the LHC

The Challenge

Three "black boxes" are given, in the form of event files in the LHC Olympics (LHCO) format and a series of selected figures.

These Black boxes are associated with signal events only. It is asked to pair up the boxes above with the three following new physics models and answer the related questions:

  • Model 1 - Extra neutral gauge boson (Z'): what is its mass and does it have Standard Model couplings to fermions?
  • Model 2 - Heavy scalar (heavy Higgs boson): what is its mass and is it a Standard Model Higgs boson?
  • Model 3 - Extra charged gauge boson (W'): what its mass and does it have Standard Model couplings to fermions?

To solve these exercises, useful extra information can be found below:

  • In the figures, $H_T=\sum ||p_T^{vis}|| + E_T^{miss}$.
  • A Z' boson with Standard Model couplings would decay (more or less democratically) into: jet jet (uu~,cc~,dd~,ss~,bb~), t tbar (tt~), l+l- (e+e-,mu+mu-,ta+ta-), neutrino anti-neutrino (ve ve~,vm vm~,vt vt~). It could also have couplings to the Standard Model W and Z bosons, and in that case would decay in to ZZ and W+W-.
  • A Higgs boson couples to particles with a strength which is proportional to the particle masses. A Standard Model-like heavy Higgs boson would decay in to t tbar (tt~), W+W- and ZZ.
  • A W' boson with Standard Model-like couplings would decay into: jet jet (ud~,cs~), t b (tb~), lepton-neutrino (e+ ve , mu+ vm, ta+ vt). It could also have couplings to the Standard Model W and Z bosons, and in that case would decay in to ZW.

Animations

Slides

Attachments