Abstract

A search for the Standard Model Higgs boson with the ATLAS experiment at the LHC is presented. The pp collisions datasets correspond to an integrated luminosity of up to 4.9fb−1 collected at s=7TeV in 2011, and up to 5.9fb−1 collected at s=8TeV in 2012. Searches for H→γγ, H→ZZ(⁎), H→WW(⁎), H→bb¯ and H→τ+τ− have been performed on the 2011 data, while H→γγ and H→ZZ(⁎)→4l have been updated using both 2011 and 2012 data. The Standard Model Higgs boson has been excluded at 95% confidence level for masses in the range of 110 to 122.6 GeV and 129.7 to 558 GeV. An excess of events has been observed for a Higgs boson mass hypothesis near 126.5 GeV with a local significance of 5.0σ.

Highlights

  • The ATLAS detector [1] was built to observe a wide spectrum of events from proton-proton collisions produced at the Large Hadron Collider (LHC)

  • While the production cross section and branching ratios can be determined for a given Higgs boson mass, mH, the actual value of the Higgs boson mass is not known and the search must be performed over a wide range of Higgs boson masses

  • Exclusion limits are based on the CLs prescription [17] such that a value of μ is regarded as excluded at the 95% confidence level (CL) when CLs is less than 5%

Read more

Summary

Introduction

The ATLAS detector [1] was built to observe a wide spectrum of events from proton-proton (pp) collisions produced at the Large Hadron Collider (LHC). In 2011, the LHC delivered to the ATLAS detector an integrated luminosity of 5.6 fb−1 of pp collisions at a centre-of-mass energy of 7 TeV. Between 4.6 and 4.9 fb−1 (depending on the data quality requirements of the specific channels) were used for 2011 analyses These analyses performed on 2011 data were combined to report the indication of an excess with a mass near 126.5 GeV with a local significance of 2.0 standard deviations (σ) [12]. As of July 2012, the LHC has delivered to the ATLAS detector an integrated luminosity of 6.6 fb−1 at a centre-of-mass energy of 8 TeV. The H → γγ was shown to be relatively insensitive to pile-up, while the H → ZZ(∗) → 4l analysis has been improved to increase pile-up robustness These analyses have been updated with 5.8 and 5.9 fb−1 of the 2012 8 TeV data, respectively.

10 ATLAS 2011
10-1 CLs Limits
Combined Results
Findings
Conclusion
Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.