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Title: Exotic decays of the 125 GeV Higgs boson at future e +e colliders

Abstract

Discovery of unexpected properties of the Higgs boson offers an intriguing opportunity of shedding light on some of the most profound puzzles in particle physics. The Beyond Standard Model (BSM) decays of the Higgs boson could reveal new physics in a direct manner. Future electron-positron lepton colliders operating as Higgs factories, including CEPC, FCC-ee and ILC, with the advantages of a clean collider environment and large statistics, could greatly enhance the sensitivity in searching for these BSM decays. In this work, we perform a general study of Higgs exotic decays at future $e^+e^-$ lepton colliders, focusing on the Higgs decays with hadronic final states and/or missing energy, which are very challenging for the High-Luminosity program of the Large Hadron Collider (HL-LHC). We show that with simple selection cuts, $$O(10^{-3}\sim10^{-5})$$ limits on the Higgs exotic decay branching fractions can be achieved using the leptonic decaying spectator $Z$ boson in the associated production mode $$e^+e^-\rightarrow Z H$$. We further discuss the interplay between the detector performance and Higgs exotic decay, and other possibilities of exotic decays. Finally, our work is a first step in a comprehensive study of Higgs exotic decays at future lepton colliders, which is a key ingredient of Higgs physics that deserves further investigation.

Authors:
ORCiD logo [1];  [2]; ORCiD logo [3]
  1. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
  2. The Univ. of Chicago, Chicago, IL (United States)
  3. Chinese Academy of Sciences (CAS), Beijing (China)
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
OSTI Identifier:
1345611
Report Number(s):
FERMILAB-PUB-16-608-T; arXiv:1612.09284
Journal ID: ISSN 1674-1137; 1507128
Grant/Contract Number:
AC02-07CH11359
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Chinese Physics. C, High Energy Physics and Nuclear Physics
Additional Journal Information:
Journal Volume: 41; Journal Issue: 6; Journal ID: ISSN 1674-1137
Publisher:
IOP Publishing
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Higgs; exotic decay; BSM; lepton collider; Higgs factory

Citation Formats

Liu, Zhen, Wang, Lian -Tao, and Zhang, Hao. Exotic decays of the 125 GeV Higgs boson at future e+e– colliders. United States: N. p., 2017. Web. doi:10.1088/1674-1137/41/6/063102.
Liu, Zhen, Wang, Lian -Tao, & Zhang, Hao. Exotic decays of the 125 GeV Higgs boson at future e+e– colliders. United States. doi:10.1088/1674-1137/41/6/063102.
Liu, Zhen, Wang, Lian -Tao, and Zhang, Hao. Thu . "Exotic decays of the 125 GeV Higgs boson at future e+e– colliders". United States. doi:10.1088/1674-1137/41/6/063102. https://www.osti.gov/servlets/purl/1345611.
@article{osti_1345611,
title = {Exotic decays of the 125 GeV Higgs boson at future e+e– colliders},
author = {Liu, Zhen and Wang, Lian -Tao and Zhang, Hao},
abstractNote = {Discovery of unexpected properties of the Higgs boson offers an intriguing opportunity of shedding light on some of the most profound puzzles in particle physics. The Beyond Standard Model (BSM) decays of the Higgs boson could reveal new physics in a direct manner. Future electron-positron lepton colliders operating as Higgs factories, including CEPC, FCC-ee and ILC, with the advantages of a clean collider environment and large statistics, could greatly enhance the sensitivity in searching for these BSM decays. In this work, we perform a general study of Higgs exotic decays at future $e^+e^-$ lepton colliders, focusing on the Higgs decays with hadronic final states and/or missing energy, which are very challenging for the High-Luminosity program of the Large Hadron Collider (HL-LHC). We show that with simple selection cuts, $O(10^{-3}\sim10^{-5})$ limits on the Higgs exotic decay branching fractions can be achieved using the leptonic decaying spectator $Z$ boson in the associated production mode $e^+e^-\rightarrow Z H$. We further discuss the interplay between the detector performance and Higgs exotic decay, and other possibilities of exotic decays. Finally, our work is a first step in a comprehensive study of Higgs exotic decays at future lepton colliders, which is a key ingredient of Higgs physics that deserves further investigation.},
doi = {10.1088/1674-1137/41/6/063102},
journal = {Chinese Physics. C, High Energy Physics and Nuclear Physics},
number = 6,
volume = 41,
place = {United States},
year = {Thu Jun 01 00:00:00 EDT 2017},
month = {Thu Jun 01 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
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  • We reveal a set of novel decay topologies for the 125 GeV Higgs boson in supersymmetry which are initiated by its decay into a pair of neutralinos, and discuss their collider search strategies. This category of exotic Higgs decays are characterized by the collider signature: visible objects +more » $$\mbox{$${\not\! E}_{\rm T}$}$, with $$\mbox{$${\not\! E}_{\rm T}$}$ dominantly arising from escaping dark matter particles. Their benchmark arises naturally in the Peccei-Quinn symmetry limit of the MSSM singlet-extensions, which is typified by the co-existence of three light particles: singlet-like scalar $$h_1$$ and pseudoscalar $$a_1$$, and singlino-like neutralino $$\chi_1$$, all with masses of $$\lesssim 10$$ GeV, and the generically suppression of the exotic decays of the 125 GeV Higgs boson $$h_2\to h_1 h_1$$, $$a_1a_1$$ and $$\chi_1\chi_1$$, however. As an illustration, we study the decay topology: $$h_2 \to \chi_1 \chi_2$$, where the bino-like $$\chi_2$$ decays to $$h_1 \chi_1$$ or $$a_1 \chi_1$$, and $$h_1/a_1 \to f\bar f$$, with $$f\bar f = \mu^+\mu^-$$, $$b\bar b$$. In the di-muon case ($$m_{h_1/a_1} \sim 1$$ GeV), a statistical sensitivity of $$\frac{S}{\sqrt{B}} > 6 \sigma$$ can be achieved easily at the 8 TeV LHC, assuming $$\frac{\sigma(pp \rightarrow W h_2)}{\sigma(pp \rightarrow W h_{\rm SM})} {\rm Br}(h_2 \to \mu^+\mu^- \chi_1 \chi_1)=0.1$$. In the $$b\bar b$$ case ($$m_{h_1/a_1} \sim 45$$ GeV), 600 fb$$^{-1}$$ data at the 14 TeV LHC can lead to a statistical sensitivity of $$\frac{S}{\sqrt{B}} > 5 \sigma$$, assuming $$\frac{\sigma(pp \rightarrow Z h_2)}{\sigma(pp \rightarrow Z h_{\rm SM})} {\rm Br}(h_2 \to b\bar b \chi_1 \chi_1)=0.5$$. These exotic decays open a new avenue for exploring new physics couplings with the 125 GeV Higgs boson at colliders.« less
  • We perform an extensive survey of nonstandard Higgs decays that are consistent with the 125 GeV Higgs-like resonance. Our aim is to motivate a large set of new experimental analyses on the existing and forthcoming data from the Large Hadron Collider (LHC). The explicit search for exotic Higgs decays presents a largely untapped discovery opportunity for the LHC collaborations, as such decays may be easily missed by other searches. We emphasize that the Higgs is uniquely sensitive to the potential existence of new weakly coupled particles and provide a unified discussion of a large class of both simplified and completemore » models that give rise to characteristic patterns of exotic Higgs decays. We assess the status of exotic Higgs decays after LHC run I. In many cases we are able to set new nontrivial constraints by reinterpreting existing experimental analyses. We point out that improvements are possible with dedicated analyses and perform some preliminary collider studies. As a result, we prioritize the analyses according to their theoretical motivation and their experimental feasibility.« less