Search for a light pseudoscalar Higgs boson in the dimuon decay channel in pp collisions at sqrt{s} = 7 TeV

Published in Physical Review Letters http://cds.cern.ch/record/1458514?ln=en

What follows is a condensed description with plots for the analysis CMS-HIG-12-004

Abstract

The dimuon invariant mass spectrum is investigated in the mass range between 5.5 GeV and 14 GeV using 1.3 fb^-1 of pp collision data at a center of mass energy of 7 TeV collected by the CMS detector at the LHC to search for a light pseudoscalar Higgs boson. Such a light Higgs boson is predicted in many models, including the Next-to-Minimal Supersymmetric Standard Model (NMSSM) which avoids the m-term problem of the MSSM. A limit on the cross section times branching ratio is set.

Main Results

We perform a search for a narrow, low mass, pseudoscalar a which is produced by and decays via in the mass ranges 5.5-8.8 GeV and 11.5-14 GeV, using a data sample corresponding to 1.3 fb^-1 collected with the CMS detector. Given the good agreement with SM background predictions, we set upper limits on the cross section times branching ratio of in the mass ranges considered. These upper limits are applied in the context of the light pseudoscalar a₁ of the NMSSM to yield upper limits on the NMSSM parameter , which specifies the fraction by which the a₁ overlaps the MSSM doublet Higgs fields at the amplitude level. These limits are superior to those from BaBar for a significant portion of the mass range, and are the only limits available in the mass range.

Figures from the publication. They can/should be used in talks:

• data-semilog-ai.pdf: PRL: Dimuon invariant mass around Upsilon

• UpperLimitPlotNewHybrid_R1_new_crop.pdf: PRL: cross section limit for lower mass range

• UpperLimitPlotNewHybrid_R2_new_crop.pdf: PRL: cross section limit for higher mass range

• ctamaxcmsanalysis_new_crop.pdf: PRL: limit in context of the NMSSM

-- Maxwell Chertok Nov. 21, 2013

Figures from CMS-HIG-12-004

PAS Figure	Image	File	Description
Figure 1a		pdf, png	Feynman diagram for the production mechanism
Figure 1b		pdf, png	Cross section for production at s = 7 TeV for = 1, 2, 3, 10, 30, 50. We plot the cross section including all available higher order corrections as per HIGLU, especially those from resolvable parton final state contributions ()
Figure 2a		pdf, png	Dimuon invariant mass distribution for the central region after the optimization of the cuts for the background reduction. The invariant mass distributions are fitted (red curves) accounting for the three bottomonium resonances and QCD background
Figure 2b		pdf, png	Dimuon invariant mass distribution for the endcap region after the optimization of the cuts for the background reduction. The invariant mass distributions are fitted (red curves) accounting for the three bottomonium resonances and QCD background
Figure 3a		pdf, png	Invariant mass spectrum in the barrel region (y-axis zoom)
Figure 3b		pdf, png	Invariant mass spectrum in the endcap region (y-axis zoom)
Figure 4a		pdf, png	Upper limit for mass range 1
Figure 4b		pdf, png	Upper limit for mass range 2
Figure 5		pdf, png	Upper limit for . For each value in mass range 1 there is a second dotted curve that shows the limits from the BaBar analyses.

-- MarioPelliccioni - 01-Mar-2012