Discovering heavy new physics in boosted Z channels: Z→l+l− vs Z→νν¯

作     者：Mihailo Backović Thomas Flacke Jeong Han Kim Seung J. Lee 

作者机构：Center for Cosmology Particle Physics and Phenomenology—CP3 Universite Catholique de Louvain 2 Chemin du Cyclotron Louvain-la-Neuve Belgium Department of Physics Korea Advanced Institute of Science and Technology 335 Gwahak-ro Yuseong-gu Daejeon 305-701 Korea IBS Center for Theoretical Physics of the Universe 70 Yuseong-daero 1689-gil Yuseong-gu Daejeon Korea School of Physics Korea Institute for Advanced Study 85 Hoegiro Dongdaemun-gu Seoul 130-722 Korea 

出 版 物：《Physical Review D》 (Phys Rev D Part Fields Gravit Cosmol)

年 卷 期：2015年第92卷第1期

页      面：011701(R)-011701(R)页

核心收录：

学科分类：07[理学] 0827[工学-核科学与技术] 0704[理学-天文学] 0702[理学-物理学] 

基　　金：National Research Foundation of Korea (NRF) - Korea government (MEST) [2012R1A2A2A01045722] Basic Science Research Program through the National Research Foundation of Korea (NRF) - ministry of Education, Science and Technology [2013R1A1A1062597] HTCaaS group of KISTI (Korea Institute of Science and Technology Information) Korea-ERC researcher visiting program through the National Research Foundation of Korea (NRF) [2014K2a7B044399, 2014K2a7A1044408] Belgian Federal Science Policy Office through the Inter-university Attraction Pole [P7/37] 

摘      要：We propose a strategy for new physics searches in channels which contain a boosted Z boson and a boosted massive jet in the final state. Our proposal exploits the previously overlooked advantages of boosted Z→νν¯ topologies, where collimated neutrinos result in signals with large missing energy. We illustrate the advantage of this channel in a case study of singly produced TeV scale charge 2/3 fermionic top partners (T′) which decay to tZ final states. A comparison with the di-leptonic channel reveals that, despite the large tt¯ background, signals with missing energy combined with jet substructure techniques offer superior probes of new physics at TeV scales. The effect can be attributed to a factor of ∼3 enhancement in the signal cross section, coming from the branching ratio of Z→νν¯. We exploit the unique event topology of singly produced top partners to suppress the tt¯ background, as well as further improve on the existing proposals to detect T′ in the boosted di-lepton channel. Our conclusions on advantages of Z→νν¯ can be extended to most resonance searches which utilize a boosted Z boson in the final state.