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Forward-backward asymmetry as a discovery tool for Z' bosons at the LHC

Forward-backward asymmetry as a discovery tool for Z' bosons at the LHC
Forward-backward asymmetry as a discovery tool for Z' bosons at the LHC
The Forward-Backward Asymmetry (AFB) in Z? physics is commonly only perceived as the observable which possibly allows one to interpret a Z? signal appearing in the Drell-Yan channel by distinguishing different models of such (heavy) spin-1 bosons. In this paper, we revisit this issue, showing that the absence of any di-lepton rapidity cut, which is commonly used in the literature, can enhance the potential of the observable at the LHC. We moreover examine the ability of AFB in setting bounds on or even discovering a Z? at the Large Hadron Collider (LHC) concluding that it may be a powerful tool for this purpose. We analyse two different scenarios: Z?-bosons with a narrow and wide width, respectively. We find that, in the first case, the significance of the AFB search can be comparable with that of the ‘bump’ search usually adopted by the experimental collaborations; however, in being a ratio of (differential) cross sections, the AFB has the advantage of reducing experimental systematics as well as theoretical errors due to PDF uncertainties. In the second case, the AFB search can outperform the bump search in terms of differential shape, meaning the AFB distribution may be better suited for new broad resonances than the event counting strategy usually adopted in such cases.
127
Accomando, Elena
8ebc75d7-bd92-4f70-a974-7bc15ebf088f
Belyaev, Alexander
6bdb9638-5ff9-4b65-a8f2-34bae3ac34b3
Fiaschi, Juri
a417f04d-05ec-4bff-bdee-ba20ac560fa7
Mimasu, Ken
4df8b481-263e-4185-89b8-32cbd43b7c26
Moretti, Stefano
b57cf0f0-4bc3-4e02-96e3-071255366614
Shepherd-Themistocleous, Claire
a29b4897-1b61-4774-8df7-0f507d905d81
Belyaev, Alexander
6bdb9638-5ff9-4b65-a8f2-34bae3ac34b3
Accomando, Elena
8ebc75d7-bd92-4f70-a974-7bc15ebf088f
Belyaev, Alexander
6bdb9638-5ff9-4b65-a8f2-34bae3ac34b3
Fiaschi, Juri
a417f04d-05ec-4bff-bdee-ba20ac560fa7
Mimasu, Ken
4df8b481-263e-4185-89b8-32cbd43b7c26
Moretti, Stefano
b57cf0f0-4bc3-4e02-96e3-071255366614
Shepherd-Themistocleous, Claire
a29b4897-1b61-4774-8df7-0f507d905d81
Belyaev, Alexander
6bdb9638-5ff9-4b65-a8f2-34bae3ac34b3

Accomando, Elena, Belyaev, Alexander, Fiaschi, Juri, Mimasu, Ken, Moretti, Stefano, Shepherd-Themistocleous, Claire and Belyaev, Alexander (2016) Forward-backward asymmetry as a discovery tool for Z' bosons at the LHC. Journal of High Energy Physics, 2016, 127. (doi:10.1007/JHEP01(2016)127).

Record type: Article

Abstract

The Forward-Backward Asymmetry (AFB) in Z? physics is commonly only perceived as the observable which possibly allows one to interpret a Z? signal appearing in the Drell-Yan channel by distinguishing different models of such (heavy) spin-1 bosons. In this paper, we revisit this issue, showing that the absence of any di-lepton rapidity cut, which is commonly used in the literature, can enhance the potential of the observable at the LHC. We moreover examine the ability of AFB in setting bounds on or even discovering a Z? at the Large Hadron Collider (LHC) concluding that it may be a powerful tool for this purpose. We analyse two different scenarios: Z?-bosons with a narrow and wide width, respectively. We find that, in the first case, the significance of the AFB search can be comparable with that of the ‘bump’ search usually adopted by the experimental collaborations; however, in being a ratio of (differential) cross sections, the AFB has the advantage of reducing experimental systematics as well as theoretical errors due to PDF uncertainties. In the second case, the AFB search can outperform the bump search in terms of differential shape, meaning the AFB distribution may be better suited for new broad resonances than the event counting strategy usually adopted in such cases.

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More information

Accepted/In Press date: 26 November 2015
Published date: 20 January 2016
Additional Information: 27 pages, 17 figures
Organisations: Physics & Astronomy, Theory Group

Identifiers

Local EPrints ID: 402044
URI: http://eprints.soton.ac.uk/id/eprint/402044
PURE UUID: 974b5ab4-1498-46c5-9225-d1825af567c8
ORCID for Alexander Belyaev: ORCID iD orcid.org/0000-0002-1733-4408
ORCID for Alexander Belyaev: ORCID iD orcid.org/0000-0002-1733-4408

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Date deposited: 27 Oct 2016 09:10
Last modified: 17 Dec 2019 01:44

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