On resonance search in dijet events at the LHC

TL;DR

This paper proposes a new strategy for resonance searches in dijet events at the LHC, emphasizing the use of angular distributions and tailored cuts to distinguish exotic signals like excited bosons from QCD background.

Contribution

It introduces a novel approach that utilizes specific angular distributions and cuts to improve the detection and identification of exotic resonances such as excited bosons.

Findings

Different cuts are needed depending on the resonance type.

Excited bosons can produce a dip in the centrality ratio distribution.

Angular distributions help confirm the resonance nature.

Abstract

New strategy for resonance search in dijet events at the LHC is discussed. The main distribution used for a bump search is the dijet invariant mass distribution with appropriated cuts. The crucial cut, which is applied to maximize signal significance, is on (pseudo)rapidity difference between the two jets. This is due to the exponential growing of the QCD background contribution with this variable. Usually it is assumed that signal from almost all exotic models populates the central dijet rapidity region y_{1,2} ~ 0 and |y_1-y_2| ~ 0. By contrast, the excited bosons do not contribute into this region, but produce an excess of dijet events over the almost flat QCD background in chi = exp|y_1-y_2| away from this region. Therefore, different sets of cuts should be applied for new physics search depending on the searched resonance properties. In order to confirm the bump and reveal the resonance nature various angular distributions should be used in addition. In particular, for the excited bosons the special choice of parameters could lead to a dip in the centrality ratio distribution over the dijet invariant mass instead of a bump, expected in the most exotic models.