Geolocating the Higgs Boson Candidate at the LHC

Abstract

The latest results from the ATLAS and CMS experiments at the CERN Large Hadron Collider (LHC) unequivocally confirm the existence of a resonance, $X$, with mass near 125 GeV which could be the Higgs boson of the Standard Model. Measuring the properties (quantum numbers and couplings) of this resonance is of paramount importance. Initial analyses by the LHC collaborations disfavor specific alternative benchmark hypotheses, e.g. pure pseudoscalars or gravitons. However, this is just the first step in a long-term program of detailed measurements. We consider the most general set of operators in the decay channels $X \to ZZ$, $WW$, $Zγ$, $γγ$ and derive the constraint implied by the measured rate. This allows us to provide a useful parametrization of the orthogonal independent Higgs coupling degrees of freedom as coordinates on a suitably defined sphere.

Figures (4)

• Figure 1: The principle of geolocating: the change of variables (\ref{['COV']}) inflates (a) the hyper-surface defined by the measurement (\ref{['GammaZZ']}) into (b) a perfect sphere.
• Figure 2: The effective couplings $\kappa_i$ and the signal efficiency after cuts as a function of latitude ($\phi$) and longitude ($\lambda$) for the different flavor 4 lepton channel $X\to ZZ\to 2e2\mu$.
• Figure 3: Unit-normalized $M_{Z_2}$ distributions for four different theory benchmarks $(\kappa_1,\kappa_2,\kappa_3)$.
• Figure 4: Distribution of the best fit values for the Higgs geolocation in 1000 pseudoexperiments with 300 $X\to ZZ\to 2\mu2e$ signal events each, for four different benchmark points.