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Combination of the Searches for Pair -Produced Vectorlike Partners of the Third -Generation Quarks at s =13 TeV with the ATLAS Detector

Research output: Contribution to journalJournal article

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Article number211801
<mark>Journal publication date</mark>20/11/2018
<mark>Journal</mark>Physical review letters
Issue number21
Volume121
Number of pages20
Publication statusPublished
Original languageEnglish

Abstract

A combination of the searches for pair-produced vectorlike partners of the top and bottom quarks in various decay channels (T→Zt/Wb/Ht, B→Zb/Wt/Hb) is performed using 36.1 fb -1 of pp collision data at s=13 TeV with the ATLAS detector at the Large Hadron Collider. The observed data are found to be in good agreement with the standard model background prediction in all individual searches. Therefore, combined 95% confidence -level upper limits are set on the production cross section for a range of vectorlike quark scenarios, significantly improving upon the reach of the individual searches. Model -independent limits are set assuming the vectorlike quarks decay to standard model particles. A singlet T is excluded for masses below 1.31 TeV and a singlet B is excluded for masses below 1.22 TeV. Assuming a weak isospin (T,B) doublet and |VTb|â‰|VtB|, T and B masses below 1.37 TeV are excluded. © 2018 CERN. for the ATLAS Collaboration.

Bibliographic note

Export Date: 13 December 2018 CODEN: PRLTA Correspondence Address: Aaboud, M.; Faculté des Sciences, Université Mohamed Premier and LPTPMMorocco References: Susskind, L., Dynamics of spontaneous symmetry breaking in the Weinberg -Salam theory (1979) Phys. Rev. D, 20, p. 2619; Arkani -Hamed, N., Cohen, A.G., Katz, E., Nelson, A.E., The littlest Higgs J. High Energy Phys., 2002 (7), p. 034; Schmaltz, M., Tucker -Smith, D., Little Higgs theories (2005) Annu. Rev. Nucl. Part. Sci., 55, p. 229; Kaplan, D.B., Georgi, H., Dimopoulos, S., Composite Higgs scalars (1984) Phys. Lett. B, 136 B, p. 187; Agashe, K., Contino, R., Pomarol, A., The minimal composite Higgs model (2005) Nucl. Phys., B719, p. 165; Hill, C.T., Simmons, E.H., Strong dynamics and electroweak symmetry breaking (2003) Phys. Rep., 381, p. 235; Del Aguila, F., Bowick, M.J., The possibility of new fermions with (Equation presented) mass (1983) Nucl. Phys., B224, p. 107; Aguilar -Saavedra, J.A., Identifying top partners at LHC J. High Energy Phys., 2009 (11), p. 030; Aguilar -Saavedra, J.A., Mixing with vector -like quarks: Constraints and expectations (2013) EPJ Web Conf., 60, p. 16012; Aguilar -Saavedra, J.A., Benbrik, R., Heinemeyer, S., Perez -Victoria, M., Handbook of vectorlike quarks: Mixing and single production (2013) Phys. Rev. D, 88, p. 094010; Atre, A., Carena, M., Han, T., Santiago, J., Heavy quarks above the top at the Tevatron (2009) Phys. Rev. D, 79, p. 054018; Atre, A., Azuelos, G., Carena, M., Han, T., Ozcan, E., Santiago, J., Unel, G., Model -independent searches for new quarks at the LHC J. High Energy Phys., 2011 (8), p. 080; Czakon, M., Mitov, A., Top++: A program for the calculation of the top -pair cross -section at hadron colliders (2014) Comput. Phys. Commun., 185, p. 2930; Cabibbo, N., Unitary Symmetry and Leptonic Decays (1963) Phys. Rev. Lett., 10, p. 531; Kobayashi, M., Maskawa, T., (Equation presented) violation in the renormalizable theory of weak interaction (1973) Prog. Theor. Phys., 49, p. 652; Search for pair production of up -type vector -like quarks and for four -topquark events in final states with multiple (Equation presented) -jets with the ATLAS detector J. High Energy Phys., 2018 (7), p. 089. , ATLAS Collaboration; Search for pair production of heavy vector -like quarks decaying to high -(Equation presented) (Equation presented) bosons and (Equation presented) quarks in the lepton -plus -jets final state in (Equation presented) collisions at (Equation presented) with the ATLAS detector J. High Energy Phys., 2017 (10), p. 141. , ATLAS Collaboration; Search for pair production of heavy vector -like quarks decaying into high -(Equation presented) (Equation presented) bosons and top quarks in the lepton -plus -jets final state in (Equation presented) collisions at (Equation presented) with the ATLAS detector J. High Energy Phys., 2018 (8), p. 048. , ATLAS Collaboration; Search for pair production of vector -like top quarks in events with one lepton, jets, and missing transverse momentum in (Equation presented) (Equation presented) collisions with the ATLAS detector J. High Energy Phys., 2017 (8), p. 052. , ATLAS Collaboration; Search for Pair - And Single -production of Vector -like Quarks in Final States with at Least One (Equation Presented) Boson Decaying into a Pair of Electrons or Muons in (Equation Presented) Collision Data Collected with the ATLAS Detector at (Equation Presented), , ATLAS Collaboration; Search for New Phenomena in Events with Same -charge Leptons and (Equation Presented) -jets in (Equation Presented) Collisions at (Equation Presented) with the ATLAS Detector, , ATLAS Collaboration; Search for Pair Production of Heavy Vector -like Quarks Decaying into Hadronic Final States in (Equation Presented) Collisions at (Equation Presented) with the ATLAS Detector, , ATLAS Collaboration; Search for pair production of vector -like (Equation presented) and (Equation presented) quarks in single -lepton final states using boosted jet substructure in proton -proton collisions at (Equation presented) J. High Energy Phys., 2017 (11), p. 085. , CMS Collaboration; Search for pair production of vector -like quarks in the (Equation presented) channel from proton -proton collisions at (Equation presented) (2018) Phys. Lett. B, 779, p. 82. , CMS Collaboration; Search for vector -like (Equation presented) and (Equation presented) quark pairs in final states with leptons at (Equation presented) J. High Energy Phys., 2018 (8), p. 177. , CMS Collaboration; The ATLAS experiment at the CERN Large Hadron Collider (2008) J. Instrum., 3, p. S08003. , ATLAS Collaboration; Jet energy scale measurements and their systematic uncertainties in proton -proton collisions at (Equation presented) with the ATLAS detector (2017) Phys. Rev. D, 96, p. 072002. , ATLAS Collaboration; Electron and photon energy calibration with the ATLAS detector using LHC Run 1 data (2014) Eur. Phys. J. C, 74, p. 3071. , ATLAS Collaboration; Muon reconstruction performance of the ATLAS detector in proton -proton collision data at (Equation presented) (2016) Eur. Phys. J. C, 76, p. 292. , ATLAS Collaboration; Performance of Missing Transverse Momentum Reconstruction with the ATLAS Detector Using Proton -proton Collisions at (Equation Presented), , ATLAS Collaboration; Performance of (Equation presented) -jet identification in the ATLAS experiment (2016) J. Instrum., 11, p. P04008. , ATLAS Collaboration; Optimisation of the ATLAS (Equation Presented) -tagging Performance for the 2016 LHC Run, , https://cds.cern.ch/record/2160731, ATLAS Collaboration; Identification of Boosted, Hadronically -decaying (Equation Presented) and (Equation Presented) Bosons in (Equation Presented) Monte Carlo Simulations for ATLAS, , https://cds.cern.ch/record/2041461, ATLAS Collaboration; Nachman, B., Nef, P., Schwartzman, A., Swiatlowski, M., Wanotayaroj, C., Jets from jets: Re -clustering as a tool for large radius jet reconstruction and grooming at the LHC J. High Energy Phys., 2015 (2), p. 075; Schmidhuber, J., Deep learning in neural networks: An overview (2015) Neural Netw., 61, p. 85; Kondo, K., Dynamical likelihood method for reconstruction of events with missing momentum. I. Method and toy models (1988) J. Phys. Soc. Jpn., 57, p. 4126; Aguilar -Saavedra, J.A., PROTOS - A PROgram for TOp Simulations, , http://jaguilar.web.cern.ch/jaguilar/protos/; Ball, R.D., Bertone, V., Carrazza, S., Deans, C.S., Del Debbio, L., Forte, S., Guffanti, A., Ubiali, M., Parton distributions with LHC data (2013) Nucl. Phys., B867, p. 244; Sjöstrand, T., Mrenna, S., Skands, P.Z., A brief introduction to PYTHIA 8.1 (2008) Comput. Phys. Commun., 178, p. 852; Cacciari, M., Czakon, M., Mangano, M., Mitov, A., Nason, P., Top -pair production at hadron colliders with next -to -next -to -leading logarithmic soft -gluon resummation (2012) Phys. Lett. B, 710, p. 612; Bärnreuther, P., Czakon, M., Mitov, A., Percent -Level -Precision Physics at the Tevatron: Next -to -Next -to -Leading Order QCD Corrections to (Equation presented) (2012) Phys. Rev. Lett., 109, p. 132001; Czakon, M., Mitov, A., NNLO corrections to top -pair production at hadron colliders: The all -fermionic scattering channels J. High Energy Phys., 2012 (12), p. 054; Czakon, M., Mitov, A., NNLO corrections to top pair production at hadron colliders: The quark -gluon reaction J. High Energy Phys., 2013 (1), p. 080; Czakon, M., Fiedler, P., Mitov, A., Total Top -Quark Pair -Production Cross Section at Hadron Colliders Through (Equation presented) (2013) Phys. Rev. Lett., 110, p. 252004; Martin, A.D., Stirling, W.J., Thorne, R.S., Watt, G., Parton distributions for the LHC (2009) Eur. Phys. J. C, 63, p. 189; Martin, A.D., Stirling, W.J., Thorne, R.S., Watt, G., Uncertainties on (Equation presented) in global PDF analyses and implications for predicted hadronic cross sections (2009) Eur. Phys. J. C, 64, p. 653; Junk, T., Confidence level computation for combining searches with small statistics (1999) Nucl. Instrum. Methods Phys. Res., Sect. A, 434, p. 435; Read, A.L., Presentation of search results: The (Equation presented) technique (2002) J. Phys. G, 28, p. 2693; Cowan, G., Cranmer, K., Gross, E., Vitells, O., Asymptotic formulae for likelihood -based tests of new physics (2011) Eur. Phys. J. C, 71, p. 1554; Ballesteros, G., Carmona, A., Chala, M., Exceptional composite dark matter (2017) Eur. Phys. J. C, 77, p. 468; Maguire, E., Heinrich, L., Watt, G., HEPData: A repository for high energy physics data (2017) J. Phys. Conf. Ser., 898, p. 102006; HEPData: Combination of the Searches for Vector -like Partners of the Third Generation Quarks at (Equation Presented) with the ATLAS Detector, , https://www.hepdata.net/record/83541, ATLAS Collaboration; ATLAS Computing Acknowledgements, , https://cds.cern.ch/record/2202407, ATLAS Collaboration