A new method to distinguish hadronically decaying boosted Z bosons from W bosons using the ATLAS detector
The distribution of particles inside hadronic jets produced in the decay of boosted W and Z bosons can be used to discriminate such jets from the continuum background. Given that a jet has been identified as likely resulting from the hadronic decay of a boosted W or Z boson, this paper presents a te...
| Main Authors: | , |
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| Format: | Article |
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Springer-Verlag
2018
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| Online Access: | http://hdl.handle.net/1721.1/114240 https://orcid.org/0000-0002-7586-7253 |
| Summary: | The distribution of particles inside hadronic jets produced in the decay of boosted W and Z bosons can be used to discriminate such jets from the continuum background. Given that a jet has been identified as likely resulting from the hadronic decay of a boosted W or Z boson, this paper presents a technique for further differentiating Z bosons from W bosons. The variables used are jet mass, jet charge, and a b-tagging discriminant. A likelihood tagger is constructed from these variables and tested in the simulation of W ′ → WZ for bosons in the transverse momentum range 200 GeV < pT < 400 GeV in √s = 8 TeV pp collisions with the ATLAS detector at the LHC. For Z-boson tagging efficiencies of ϵZ = 90 , 50, and 10 % , one can achieve W + -boson tagging rejection factors (1 / ϵW + ) of 1.7, 8.3 and 1000, respectively. It is not possible to measure these efficiencies in the data due to the lack of a pure sample of high pT , hadronically decaying Z bosons. However, the modelling of the tagger inputs for boosted W bosons is studied in data using a tt¯ -enriched sample of events in 20.3 fb - 1 of data at √s= 8 TeV. The inputs are well modelled within uncertainties, which builds confidence in the expected tagger performance. |
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