Performance of Missing Transverse Momentum Reconstruction Algorithms in Proton-Proton Collisions at √s = 8 TeV with the CMS Detector (CMS-PAS-JME-12-002)

Link to CERN CDS

Abstract

The performance of missing transverse momentum reconstruction algorithms is presented using 8 TeV pp collision data collected with the CMS detector, corresponding to an integrated luminosity up to 12.2 ± 0.5 fb−1. Events with anomalous missing transverse momentum are studied, and the performance of algorithms used to identify and remove those events is presented. The scale and resolution for missing transverse momentum, including the effects of multiple pp interactions in the same, earlier, and later bunch crossings (pileup interactions), are measured using events with an identified Z boson or isolated photon. They are in general well described by the simulation. Advanced missing transverse momentum reconstruction algorithms are also developed specifically to mitigate the effects of large numbers of pileup interactions on missing transverse momentum resolution. Using these advanced algorithms, the dependence of the missing transverse momentum resolution on pileup interactions is reduced significantly.

Approved results from PAS JME-12-002

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Vertex multiplicity distribution for Zmumu candidate events in the 2012 data and MC samples.

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Dilepton invariant mass distributions in events passing the Zmumu (left) and Zee (right) selections.

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qT distributions in events with Zmumu (left), Zee (middle), and photon events (right).

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PF MET distributions for events passing the dijet selection without 2012 cleaning algorithms applied (open markers), with 2012 cleaning algorithms applied including the one based on jet identification requirements (filled markers), and events from MC (filled histograms).

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PF MET distributions in events with Zmumu (left), Zee (middle), and photon events (right).

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PF MET u_para+qT component distributions in events with Zmumu (left), Zee (middle), and photon events (right).

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PF MET u_perp component distributions in events with Zmumu (left), Zee (middle), and photon events (right).

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Response curves for PF MET for events with Z and photon. Results are shown for Zmumu events (full blue circles), Zee events (open red circles), and photon events (full green squares).

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Resolution curves of the parallel recoil component (left) and perpendicular recoil component (right) versus Z/photon qT for PF MET for events with Z and photon. Results are shown for Zmumu events (full blue circles), Zee events (open red circles), and photon events (full green squares).

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Resolution of the PF MET projection along the x-axis (left) and the y-axis (right) as a function of sumET for events with Z and photon. Results are shown for Zmumu events (full blue circles), Zee events (open red circles), and photon events (full green squares).

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Parametrization results of the resolution curves for the components of MET, as functions of sumET.

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Parallel recoil component (left) and perpendicular recoil component (right) resolution curves versus the number of reconstructed vertices for PF MET for events with Z and photon. Results are shown for Zmumu events (full blue circles), Zee events (open red circles), and photon events (full green squares).

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Parametrization results of the resolution curves for the u_para and u_perp components as functions of Nvtx.

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Parallel recoil component (left) and perpendicular recoil component (right) resolution curves for the PF MET and Calo MET algorithms versus the number of reconstructed vertices for Calo MET for Zmumu events.

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No-PU PF MET distributions in events with Zmumu (left) and Zee (right) events.

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MVA PF MET distributions in events with Zmumu (left) and Zee (right) events.

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Response as a function of qT for No-PU PF MET in Zmumu (left) and Zee (right) events.

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Response as a function of qT for MVA PF MET in Zmumu (left) and Zee (right) events.

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Parallel (top) and perpendicular (bottom) resolution as a function of qT for No-PU PF MET in Zmumu (left) and Zee (right) events.

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Parallel (top) and perpendicular (bottom) resolution as a function of qT for MVA PF MET in Zmumu (left) and Zee (right) events.

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Parallel (top) and perpendicular (bottom) resolution as a function of the number of reconstructed vertices for PF MET, No-PU PF MET, and MVA PF MET in Zmumu (left) and Zee (right) events.