• Evidence for a new boson in the search for the Standard Model Higgs particle decaying to four leptons at CMS
  • Meneghelli, Marco <1985>

Subject

  • FIS/01 Fisica sperimentale

Description

  • One of the main targets of the CMS experiment is to search for the Standard Model Higgs boson. The 4-lepton channel (from the Higgs decay h->ZZ->4l, l = e,mu) is one of the most promising. The analysis is based on the identification of two opposite-sign, same-flavor lepton pairs: leptons are required to be isolated and to come from the same primary vertex. The Higgs would be statistically revealed by the presence of a resonance peak in the 4-lepton invariant mass distribution. The 4-lepton analysis at CMS is presented, spanning on its most important aspects: lepton identification, variables of isolation, impact parameter, kinematics, event selection, background control and statistical analysis of results. The search leads to an evidence for a signal presence with a statistical significance of more than four standard deviations. The excess of data, with respect to the background-only predictions, indicates the presence of a new boson, with a mass of about 126 GeV/c2 , decaying to two Z bosons, whose characteristics are compatible with the SM Higgs ones.

Date

  • 2013-03-20

Type

  • Doctoral Thesis
  • PeerReviewed

Format

  • application/pdf

Identifier

urn:nbn:it:unibo-10374

Meneghelli, Marco (2013) Evidence for a new boson in the search for the Standard Model Higgs particle decaying to four leptons at CMS, [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Fisica , 25 Ciclo. DOI 10.6092/unibo/amsdottorato/5174.

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