Exclusive displaced hadronic signatures in the LHC forward region

Abstract The LHCb detector provides accurate vertex reconstruction and hadronic particle identification, which make the experiment an ideal place to look for light long-lived particles (LLP) decaying into Standard Model (SM) hadrons. In contrast with the typical search strategy relying on energetic...

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Main Authors: Xabier Cid Vidal, Yuhsin Tsai, Jose Zurita
Format: Article
Language:English
Published: SpringerOpen 2020-01-01
Series:Journal of High Energy Physics
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Online Access:https://doi.org/10.1007/JHEP01(2020)115
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author Xabier Cid Vidal
Yuhsin Tsai
Jose Zurita
author_facet Xabier Cid Vidal
Yuhsin Tsai
Jose Zurita
author_sort Xabier Cid Vidal
collection DOAJ
description Abstract The LHCb detector provides accurate vertex reconstruction and hadronic particle identification, which make the experiment an ideal place to look for light long-lived particles (LLP) decaying into Standard Model (SM) hadrons. In contrast with the typical search strategy relying on energetic jets and a high multiplicity of tracks from the LLP decay, LHCb can identify LLPs in exclusive, specific hadronic final states. To illustrate the idea, we study the sensitivity of LHCb to an exotic Higgs decay h → SS, followed by the displaced decay of GeV-scale scalars into charged kaons S → K+K−. We show that the reconstruction of kaon vertices in narrow invariant mass windows can efficiently eliminate the combinatorial backgrounds from B-meson decays. While the same signal is extremely difficult to probe in the existing displaced jet searches at ATLAS/CMS, the LHCb search we propose can probe the branching ratio BR(h → SS) down to 0.1% (0.02%) level with 15 (300) fb−1 of data. We also apply this projected bound to two scenarios with Higgs portal couplings, where the scalar mediator S either couples to a) the SM quarks only, or b) to both quarks and leptons in the minimal flavor violation paradigm. In both scenarios we compare the reach of our proposed search with the expected constraints from ATLAS and CMS on the invisible Higgs width and with the constraints from rare B-decays studies at LHCb. We find that for 1 GeV < mS< 2 GeV and 0.5 mm ≲ cτ ≲ 10 mm our proposed search will be competitive with the ATLAS and CMS projections, while at the same time providing crucial information of the hadronic interactions of S, which can not be obtained from the indirect measurement of the Higgs invisible width.
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spelling doaj-art-17d3cb2701bb4085b0523b530991ef342025-01-26T12:11:27ZengSpringerOpenJournal of High Energy Physics1029-84792020-01-012020111910.1007/JHEP01(2020)115Exclusive displaced hadronic signatures in the LHC forward regionXabier Cid Vidal0Yuhsin Tsai1Jose Zurita2Instituto Galego de Física de Altas Enerxías (IGFAE), Universidade de Santiago de CompostelaMaryland Center for Fundamental Physics, Department of Physics, University of MarylandInstitute for Nuclear Physics (IKP), Karlsruhe Institute of TechnologyAbstract The LHCb detector provides accurate vertex reconstruction and hadronic particle identification, which make the experiment an ideal place to look for light long-lived particles (LLP) decaying into Standard Model (SM) hadrons. In contrast with the typical search strategy relying on energetic jets and a high multiplicity of tracks from the LLP decay, LHCb can identify LLPs in exclusive, specific hadronic final states. To illustrate the idea, we study the sensitivity of LHCb to an exotic Higgs decay h → SS, followed by the displaced decay of GeV-scale scalars into charged kaons S → K+K−. We show that the reconstruction of kaon vertices in narrow invariant mass windows can efficiently eliminate the combinatorial backgrounds from B-meson decays. While the same signal is extremely difficult to probe in the existing displaced jet searches at ATLAS/CMS, the LHCb search we propose can probe the branching ratio BR(h → SS) down to 0.1% (0.02%) level with 15 (300) fb−1 of data. We also apply this projected bound to two scenarios with Higgs portal couplings, where the scalar mediator S either couples to a) the SM quarks only, or b) to both quarks and leptons in the minimal flavor violation paradigm. In both scenarios we compare the reach of our proposed search with the expected constraints from ATLAS and CMS on the invisible Higgs width and with the constraints from rare B-decays studies at LHCb. We find that for 1 GeV < mS< 2 GeV and 0.5 mm ≲ cτ ≲ 10 mm our proposed search will be competitive with the ATLAS and CMS projections, while at the same time providing crucial information of the hadronic interactions of S, which can not be obtained from the indirect measurement of the Higgs invisible width.https://doi.org/10.1007/JHEP01(2020)115Beyond Standard ModelHiggs Physics
spellingShingle Xabier Cid Vidal
Yuhsin Tsai
Jose Zurita
Exclusive displaced hadronic signatures in the LHC forward region
Journal of High Energy Physics
Beyond Standard Model
Higgs Physics
title Exclusive displaced hadronic signatures in the LHC forward region
title_full Exclusive displaced hadronic signatures in the LHC forward region
title_fullStr Exclusive displaced hadronic signatures in the LHC forward region
title_full_unstemmed Exclusive displaced hadronic signatures in the LHC forward region
title_short Exclusive displaced hadronic signatures in the LHC forward region
title_sort exclusive displaced hadronic signatures in the lhc forward region
topic Beyond Standard Model
Higgs Physics
url https://doi.org/10.1007/JHEP01(2020)115
work_keys_str_mv AT xabiercidvidal exclusivedisplacedhadronicsignaturesinthelhcforwardregion
AT yuhsintsai exclusivedisplacedhadronicsignaturesinthelhcforwardregion
AT josezurita exclusivedisplacedhadronicsignaturesinthelhcforwardregion