Background Parameterization Uncertainties in the Search for the Doubly Charged Higgs Boson
Session Number
3
Advisor(s)
Dr. Peter Dong, IMSA Compact Muon Solenoid Large Hadron Collider Physics Center (IMSA CMS-LPC)
Location
A131
Discipline
Physical Science
Start Date
15-4-2026 2:15 PM
End Date
15-4-2026 3:00 PM
Abstract
The doubly charged Higgs boson (H++) is a hypothetical particle predicted by some Type II Seesaw Mechanisms, an extension of the Standard Model (SM) that adds a Higgs triplet containing neutral, singly charged, and doubly charged bosons. At the Large Hadron Collider (LHC), the H++ is primarily produced via an s-channel process and identified by its decay into same-sign lepton pairs, a signature rarely produced by SM processes. Searches for the H++ require unbinned likelihood fits of background distributions, which necessitate background parameterization. Because different parameterization functions yield different limits, parameterization choice introduces a source of systematic uncertainty. This study evaluated multiple background parameterization functions, including a power-law model and a semi-Gaussian log power norm, across the ZZ, Drell-Yan, and other background channels, testing varied fit ranges to assess sensitivity. By comparing fit results across functions and ranges, particularly above 1000 GeV mass threshold, this study aimed to quantify a justified parameterization uncertainty that accounts for any variation in the limit that would be caused by the choice of parameterization function.
Background Parameterization Uncertainties in the Search for the Doubly Charged Higgs Boson
A131
The doubly charged Higgs boson (H++) is a hypothetical particle predicted by some Type II Seesaw Mechanisms, an extension of the Standard Model (SM) that adds a Higgs triplet containing neutral, singly charged, and doubly charged bosons. At the Large Hadron Collider (LHC), the H++ is primarily produced via an s-channel process and identified by its decay into same-sign lepton pairs, a signature rarely produced by SM processes. Searches for the H++ require unbinned likelihood fits of background distributions, which necessitate background parameterization. Because different parameterization functions yield different limits, parameterization choice introduces a source of systematic uncertainty. This study evaluated multiple background parameterization functions, including a power-law model and a semi-Gaussian log power norm, across the ZZ, Drell-Yan, and other background channels, testing varied fit ranges to assess sensitivity. By comparing fit results across functions and ranges, particularly above 1000 GeV mass threshold, this study aimed to quantify a justified parameterization uncertainty that accounts for any variation in the limit that would be caused by the choice of parameterization function.