Search for Higgs bosons decaying into photons at CMS

Matthew Kenzie

doi:10.1016/j.nuclphysbps.2015.09.134

Abstract

We present a new result in the search for Higgs bosons decaying into two photons at the CMS detector using the full LHC Run 1 dataset. The data samples correspond to integrated luminosities of 5.1 fb-1 and 19.7 fb-1 at centre-of-mass energies of 7 TeV and 8 TeV respectively. A clear signal is observed in the diphoton channel at a mass close to 125 GeV with a local significance of 5.7 σ, where 5.2 σ is expected from the standard model Higgs boson. The mass is measured to be 124.70 ± 0.34 GeV = 124.70 ± 0.31(stat) ± 0.15(syst) GeV and the signal strength relative to the standard model prediction is found to be 1.14−0.23+0.26=1.14±0.21(stat)−0.05+0.09(syst)−0.09+0.13(theo). Additional results include measurements of the signal strength modifiers with respect to different production mechanisms.

Highlights

In 2012, the ATLAS and CMS Collaborations announced the observation of a new particle whose properties where consistent with a standard model (SM) Higgs boson with a mass around 125 GeV [1, 2]
We present a new result in the search for Higgs bosons decaying into two photons at the CMS detector using the full LHC Run 1 dataset
A clear signal is observed in the diphoton channel at a mass close to 125 GeV with a local significance of 5.7 σ, where 5.2 σ is expected from the standard model Higgs boson

Summary

Introduction

In 2012, the ATLAS and CMS Collaborations announced the observation of a new particle whose properties where consistent with a SM Higgs boson with a mass around 125 GeV [1, 2]. We report on the search for the Higgs boson decaying into two photons at the CMS dectector. It summarises the work presented in Ref. Given the integrated luminsotity and centre-of-mass energies of the dataset used, around 5 × 105 SM Higgs bosons (with a mass of 125 GeV) can be expected to have been produced at CMS, of which about 1000 decay into two photons. Where L f is the unpenalised likelihood and N f is the number of free parameters in function f It is found in tests made using pseduo-experiments that this value of the corrected likelihood gives consistently good coverage and neglible bias. In all these cases the statistical properties of the method were found to be well behaved

Methods

Results

Conclusion