CMS DP-2014/007 H→γγ signal mass shape with the legacy calibrations and cluster corrections

Abstract: Full parameterized signal shape integrated over all event classes in 125 GeV Higgs Monte Carlo at √s = 8 TeV for the MVA analysis. Needed to show the evolution of the H→γγ signal resolution with different ECAL rerecoes

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Full parameterized signal shape integrated over all event classes (“combined”) in 125 GeV Higgs Monte Carlo at √s = 8 TeV for the MVA analysis. The black points are the weighted Monte Carlo events and the blue lines are the corresponding analytic model. Also shown is the effective σ value ( half-the-width of the narrowest interval containing 68.3% of the distribution ) and corresponding interval. The acceptance x efficiency is 49.3% . The energy corrections are computed using a multivariate regression technique trained on prompt photons in Monte Carlo. The input variables are the global η and φ coordinates of the Supercluster, a collection of showershape variables, and a set of local cluster coordinates. The regression is trained using a semi-parametric likelihood technique in order to construct a prediction for the full distribution of ETrue/ERaw. The improvements in the FWHM with respect to previous results are due to the improved calibration of the ECAL detector and to the improved energy corrections derived from an accurate run-dependent Monte Carlo description of the detector that follows the evolving conditions during data taking in 2012, and includes the simulation of out of time pileup over the time windows [-300 ns, +50 ns]

-- EmanueleDiMarco - 07 Apr 2014