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Invisible Z′ at the CERN LHC

Petriello, Frank J. and Quackenbush, Seth and Zurek, Kathryn M. (2008) Invisible Z′ at the CERN LHC. Physical Review D, 77 (11). Art. No. 115020. ISSN 1550-7998. doi:10.1103/physrevd.77.115020.

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We study the feasibility of observing an invisibly decaying Z′ at the LHC through the process pp→ZZ′→ℓ^+ℓ^−XX^†, where X is any neutral, (quasi-) stable particle, whether a standard model neutrino or a new state. The measurement of the invisible width through this process facilitates both a model-independent measurement of Γ_(Z′→ṽν and potentially detection of light neutral hidden states. Such particles appear in many models, where the Z′ is a messenger to a hidden sector, and also if dark matter is charged under the U(1)′ of the Z′. We find that with as few as 30 fb^(−1) of data the invisibly decaying Z′ can be observed at 5σ over standard model background for a 1 TeV Z′ with reasonable couplings. If the Z′ does not couple to leptons and therefore cannot be observed in the Drell-Yan channel, this process becomes a discovery mode. For reasonable hidden sector couplings, masses up to 2 TeV can be probed at the LHC. If the Z′ does couple to leptons, then the rate for this invisible decay is predicted by on-peak data and the presence of additional hidden states can be searched for. With 100 fb^(−1) of data, the presence of excess decays to hidden states can be excluded at 95% C.L., if they comprise 20–30% of the total invisible cross section.

Item Type:Article
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URLURL TypeDescription Paper
Alternate Title:The Invisible Z' at the LHC
Additional Information:© 2008 American Physical Society. (Received 9 April 2008; published 24 June 2008) The authors are supported by the DOE grant DE-FG02-95ER40896 by the University of Wisconsin Research Committee with funds provided by the Wisconsin Alumni Research Foundation, and by the Alfred P. Sloan Foundation.
Funding AgencyGrant Number
Department of Energy (DOE)DE-FG02-95ER40896
Wisconsin Alumni Research FoundationUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Issue or Number:11
Classification Code:PACS numbers: 12.60.Cn, 12.60.Jv, 14.70.Pw
Record Number:CaltechAUTHORS:20190611-125827506
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:96291
Deposited By: George Porter
Deposited On:12 Jun 2019 18:22
Last Modified:16 Nov 2021 17:19

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