Source-linked AI summary
Discovering baryon-number violating neutralino decays at the LHC
Jonathan M. Butterworth, John R. Ellis, Are R. Raklev, Gavin P. Salam
TL;DR
Baryon-number-violating neutralino decays are difficult to extract because large hadronic activity can overwhelm their signal against QCD backgrounds. The analyses exploit composite jets from boosted neutralinos, using kT and Cambridge/Aachen subjet structure, mass-related merger scales, and cuts designed for three-body decays. With 1 fb−1, significance is well above the 5-σ discovery ‘threshold’ even in the highest-mass SPS1a case studied; the kT analysis reconstructs 3.3% in a 20 GeV window.
Problem
Baryon-number-violating neutralino decays are difficult to extract because large hadronic activity can overwhelm their signal against QCD backgrounds.
Source: p. 1Method
The analyses exploit composite jets from boosted neutralinos, using kT and Cambridge/Aachen subjet structure, mass-related merger scales, and cuts designed for three-body decays.
Source: pp. 1–3Results
With 1 fb−1, significance is well above the 5-σ discovery ‘threshold’ even in the highest-mass SPS1a case studied; the kT analysis reconstructs 3.3% in a 20 GeV window.
Source: pp. 2–3Takeaways & Limitations
The study demonstrates that baryon-number-violating neutralino decays might be observed directly and their mass reconstructed using jet substructure rather than relying on model-dependent leptonic signatures.
Source: pp. 1, 3The background distribution can develop a peak near the neutralino mass, with its position depending on jet radius, jet pT, and substructure cuts; pile-up, detector resolution, and calorimeter granularity also affect discovery and mass measurement.
Source: pp. 2, 4
Abstract
from arXiv · showhide
Recently there has been much interest in the use of single-jet mass and jet substructure to identify boosted particles decaying hadronically at the LHC. We develop these ideas to address the challenging case of a neutralino decaying to three quarks in models with baryonic violation of R-parity. These decays have previously been found to be swamped by QCD backgrounds. We demonstrate for the first time that such a decay might be observed directly at the LHC with high significance, by exploiting characteristics of the scales at which its composite jet breaks up into subjets.