Search for Higgs-like bosons decaying into long-lived exotic particles

The conference note for the preliminary results is available: LHCb-CONF-2012-014.

More detailed information: ANA note 2012-038

Abstract

Several beyond the Standard Model theoretical models predict the existence of Higgs bosons decaying into heavy long-lived particles. We have analyzed the LHCb data collected from pp collisions at √s = 7 TeV in 2010 corresponding to an integrated luminosity of 35.8 pb−1 , to identify secondary vertices which can be associated with the decay of such particles. The candidates are subsequently combined to reconstruct the parent bosons. The approximate sensitivity range of this analysis covers long-lived particle lifetimes from 3 to 25 ps, masses between 30 and 55 GeV/c^2 , and parent Higgs masses of 100125 GeV/c^2 . We do not observe evidence for the production of these long lived states, and set limits on their production times branching ratio.

Figures

pdf and eps version are available in attachment.

Caption Figure
Distribution in x and z, for abs(y) < 1 mm, of the reconstructed LPP candidate vertices. Most candidates are background from interactions with matter. The visible structures reflect the geometry of the VELO detector, with the doublets of silicon sensors appearing as pairs of vertical bands and the RF foil (shielding the sensors from the RF perturbation produced by the beams) as the two wave shapes. The green shaded region represents the fiducial vacuum volume in which candidates are accepted. Fig_1.png
MC distributions compared with data results, shown with unit normalization. From top left to bottom right: number of tracks of the LLP candidate, transverse momentum, invariant mass, pseudo-rapidity, radial r.m.s. error of the vertex, and the distance of flight. Various distributions for the LLP candidates selected in data (back dots with statistical error bars), compared with MC distributions for bbbar background (red solid histograms with statistical error bars), BV48 signal (blue dashed histograms) and HV10 signal (green dotted histogram). Fig_2a.png
  Fig_2b.png
  Fig_2c.png
  Fig_2d.png
  Fig_2e.png
  Fig_2f.png
Distributions for pairs of LLP candidates selected in data (black dots with statistical error bars), compared with MC distributions for bb background (red solid histograms with statistical error bars), BV48 signal (blue dashed histograms) and HV10 signal (green dotted histogram), each normalized to one. From top to bottom and left to right: azimuthal angle difference, pT of the pair and invariant mass of the pair. Fig_3a.png
  Fig_3b.png
  Fig_3c.png
Mass distribution of the Higgs candidates (black data points), together with the result of the fit (red band reflecting the statistical precision of the model, and dotted blue signal component multiplied by 100). Fig_4a.png
  Fig_4b.png

-- TaraShears - 18-Sep-2012

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This topic: LHCb > LHCbQEEPublicResults > PrelimDsiplVert
Topic revision: r2 - 2014-01-17 - KatharinaMueller
 
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