Fourth Generation Quarks in Generated Data Analysis

Fourth Generation Quarks in Generated Data Analysis

Names: Triton Wolfe, Olathe North High School
Christopher Fenton, Olathe North High School

Research Teacher Mentor: James Deane, Ottawa High School, Ottawa, KS

Research Mentor: Prof. Philip Baringer, University of Kansas, Lawrence, KS

Purpose: The discovery of fourth generation quarks could provide support for supersymmetry which could help explain the low mass of the Higgs boson, the imbalance of matter vs. antimatter, the effects of dark matter, and the origin of mass.

Methods: We learned to use C++ in ROOT for our data analysis, following tutorials provided by fellow students. We had to teach ourselves C++ structure in ROOT functions. We also learned how to use MadGraph to generate Monte Carlo data for specific particle decays. We created cuts for generated t` decays with the module having a mass of 750GeV and 1000GeV. We first generated simulated decays in MadGraph using the commands p p _ t t~, (t _ b w+, w+ _ j j), (t~ _ b~ w-, w- _ j j), and then used the macros of the resulting files creating limits like Particle_Status == 2 (Stable particles), Particle_Pt > 15 to eliminate lower energy events that could not be decays of t`, and abs(Particle_Eta) <= 5 to select for lower Eta values that would indicate higher energy t` decays. Macros with those limitations were created for Number of BJets per event, Number of Jets per event, dR vs. Number of events, Eta vs. Pt, Forward Jets, Ht vs. Number of events, and Pt vs. Number of Jets.

Results: The developed macros were compared to the macros of the t` generated files with masses of 750GeV and 1000GeV, setting specific cut values to apply to the t` generated files. The cuts were then applied to determine what events remained. The remaining events were possible places where a t` particle could have existed. After developing these macros and running analyses on the generated files, we now possess most of the tools and knowledge we need to work on genuine CERN data and search for fourth generation quarks, specifically the t` particle.

Meaning to Larger Project: The search for ultra-heavy fourth-generation particles such as the t` is part of the investigation of the frontiers of particle physics. Developing and testing cut values with Monte Carlo data prepares us to analyze real data and narrow down the candidates for the t` fourth-generation quark.

Future Research: Once we receive data from CERN we will be able to remove the background and see how many events survive our cuts. Data sets that have the most surviving events will then be searched for t` particles.

We appreciate the assistance and guidance of the following students during this project.

  • Eilish Gibson: Undergraduate Student, University of Kansas (KU QuarkNet Alumna)

  • Emily Smith: Undergraduate Student, University of Kansas

  • Erich Schmitz: Graduate Student, University of Kansas