Abstract
AbstractLarge classes of new physics theories predict the existence of new scalar states, commonly dubbed sgluons, lying in the adjoint representation of the QCD gauge group. Since these new fields are expected to decay into colored Standard Model particles, and in particular into one or two top quarks, these theories predict a possible enhancement of the hadroproduction rate associated with multitop final states. We therefore investigate multitop events produced at the Large Hadron Collider, running at a center-of-mass energy of 8 TeV, and employ those events to probe the possible existence of color adjoint scalar particles. We first construct a simplified effective field theory motivated byR-symmetric supersymmetric models where sgluon fields decay dominantly into top quarks. We then use this model to analyze the sensitivity of the Large Hadron Collider in both a multilepton plus jets and a single lepton plus jets channel. After having based our event selection strategy on the possible presence of two, three and four top quarks in the final state, we find that sgluon-induced new physics contributions to multitop cross sections as low as 10-100 fb can be excluded at the 95% confidence level, assuming an integrated luminosity of 20 fb−1. Equivalently, sgluon masses of about 500–700 GeV can be reached for several classes of benchmark scenarios.
Highlights
JHEP04(2013)043 so far and the limits on the masses of the first-generation and second-generation squarks as well as those on the mass of the gluino are pushed to a higher and higher scale [5,6,7]
We investigate multitop events produced at the Large Hadron Collider, running at a center-of-mass energy of 8 TeV, and employ those events to probe the possible existence of color adjoint scalar particles
After having based our event selection strategy on the possible presence of two, three and four top quarks in the final state, we find that sgluon-induced new physics contributions to multitop cross sections as low as 10-100 fb can be excluded at the 95% confidence level, assuming an integrated luminosity of 20 fb−1
Summary
In order to investigate sgluon production and decay at the LHC, we construct a simplified model describing sgluon interactions with the Standard Model fields. Assuming O(1) effective interactions, sgluon masses up to about 2 TeV are already excluded by dijet resonance searches [31] To evade this constraint, we choose scenarios where the sgluon field dominantly decays into final states containing at least one top quark or where its couplings to a pair of light quarks or to a pair of gluons are reduced. We choose scenarios where the sgluon field dominantly decays into final states containing at least one top quark or where its couplings to a pair of light quarks or to a pair of gluons are reduced This choice is motivated by R-symmetric supersymmetric theories and by N = 1/N = 2 hybrid supersymmetric models. Signal event samples are normalized according to the NLO results
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