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Higgs boson look-alikes at the LHC

De Rújula, A. and Lykken, Joseph and Pierini, Maurizio and Rogan, Christopher and Spiropulu, Maria (2010) Higgs boson look-alikes at the LHC. Physical Review D, 82 (1). Art. No. 013003. ISSN 2470-0010. doi:10.1103/PhysRevD.82.013003.

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The discovery of a Higgs particle is possible in a variety of search channels at the LHC. However, the true identity of any putative Higgs boson will, at first, remain ambiguous until one has experimentally excluded other possible assignments of quantum numbers and couplings. We quantify the degree to which one can discriminate a standard model Higgs boson from “look-alikes” at, or close to, the moment of discovery at the LHC. We focus on the fully-reconstructible golden decay mode to a pair of Z bosons and a four-lepton final state. Considering both on-shell and off-shell Z’s, we show how to utilize the full decay information from the events, including the distributions and correlations of the five relevant angular variables. We demonstrate how the finite phase space acceptance of any LHC detector sculpts the decay distributions, a feature neglected in previous studies. We use likelihood ratios to discriminate a standard model Higgs from look-alikes with other spins or nonstandard parity, CP, or form factors. For a resonance mass of 200  GeV/c^2, we achieve a median discrimination significance of 3σ with as few as 19 events, and even better discrimination for the off-shell decays of a 145  GeV/c^2 resonance.

Item Type:Article
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Pierini, Maurizio0000-0003-1939-4268
Rogan, Christopher0000-0002-4166-4503
Spiropulu, Maria0000-0001-8172-7081
Additional Information:© 2010 The American Physical Society. Received 2 March 2010; published 14 July 2010. We especially acknowledge insights and inspiration from our late colleagues Andrew Lange and Juan Antonio Rubio. The authors are grateful to Andrew Cohen, Belén Gavela, Keith Ellis, Shelly Glashow, Ken Lane, Ken Lee, Michelangelo Mangano, Chiara Mariotti, Guido Martinelli, Sezen Sekmen, Riccardo Rattazzi, Raman Sundrum, Steven Weinberg, Jan Winter and Mark Wise for useful discussions. J. L. acknowledges the hospitality of the CERN Theory Department and support from the Aspen Center for Physics. Fermilab is operated by the Fermi Research Alliance LLC under Contract No. DEAC02- 07CH11359 with the U.S. Department of Energy. C. R. and M. S. are supported in part by the U.S. Department of Energy under Contact No. DE-FG02-92- ER40701. Note added.—While this manuscript was in preparation we received the preprint [54], reporting on an analysis similar to what we have presented here.
Funding AgencyGrant Number
Aspen Center for PhysicsUNSPECIFIED
U.S. Department of EnergyDE-AC02-07CH11359
U.S. Department of EnergyDE-FG02-92-ER40701
Issue or Number:1
Classification Code:PACS: 14.80.Bn
Record Number:CaltechAUTHORS:20100804-092621396
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:19269
Deposited By: Tony Diaz
Deposited On:04 Aug 2010 17:17
Last Modified:08 Nov 2021 23:50

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