Early (and Later) LHC Search Strategies for Broad Dimuon Resonances

TL;DR

This paper explores search strategies for broad dimuon resonances at the LHC, demonstrating statistical methods to detect them and introducing ellipticity as a new angular measure for model discrimination early in LHC operations.

Contribution

It introduces ellipticity, a novel angular observable, and demonstrates effective statistical techniques for identifying broad resonances in early LHC data.

Findings

Statistical methods can effectively detect broad resonances.

Ellipticity outperforms existing observables in identifying parity violation.

The approach covers previously unexplored parameter space.

Abstract

Resonance searches generally focus on narrow states that would produce a sharp peak rising over background. Early LHC running will, however, be sensitive primarily to broad resonances. In this paper we demonstrate that statistical methods should suffice to find broad resonances and distinguish them from both background and contact interactions over a large range of previously unexplored parameter space. We furthermore introduce an angular measure we call ellipticity, which measures how forward (or backward) the muon is in eta, and allows for discrimination between models with different parity violation early in the LHC running. We contrast this with existing angular observables and demonstrate that ellipticity is superior for discrimination based on parity violation, while others are better at spin determination.