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. © 2016, CERN for the benefit of the ATLAS collaboration.
A new method to distinguish hadronically decaying boosted Z bosons from W bosons using the ATLAS detector / Aad, G., Aloisio, A., Alviggi, M., Canale, V., DELLA VOLPE, D., Merola, L., Conventi, F., DELLA PIETRA, M., Giordano, R., Perrella, S., Rossi, E., Cirotto, F., SANCHEZ PINEDA, A.R., Carlino, G., DE ASMUNDIS, R., DI DONATO, C., Doria, A., Iengo, P., Izzo, V., Sekhniaidze, G., et al.. - In: THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6044. - 76:5(2016). [10.1140/epjc/s10052-016-4065-1]
A new method to distinguish hadronically decaying boosted Z bosons from W bosons using the ATLAS detector
ALOISIO, ALBERTO;ALVIGGI, MARIAGRAZIA;CANALE, VINCENZO;DELLA VOLPE, DOMENICO;MEROLA, LEONARDO;CONVENTI, FRANCESCO;DELLA PIETRA, MASSIMO;GIORDANO, RAFFAELE;PERRELLA, SABRINA;ROSSI, ELVIRA;CIROTTO, FRANCESCO;SANCHEZ PINEDA, ARTURO RODOLFO;CARLINO, GIANPAOLO;DE ASMUNDIS, Riccardo;DI DONATO, CAMILLA;IENGO, PAOLO;IZZO, VINCENZO;
2016
Abstract
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. © 2016, CERN for the benefit of the ATLAS collaboration.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
