scholarly journals Exotic Higgs decays into displaced jets at the LHeC

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Kingman Cheung ◽  
Oliver Fischer ◽  
Zeren Simon Wang ◽  
Jose Zurita

Abstract Profiling the Higgs boson requires the study of its non-standard decay modes. In this work we discuss the prospects of the Large Hadron electron Collider (LHeC) to detect scalar particles with masses ,≳ 10 GeV produced from decays of the Standard Model (SM) Higgs boson. These scalar particles decay mainly to bottom pairs, and in a vast portion of the allowed parameter space they acquire a macroscopic lifetime, hence giving rise to displaced hadronic vertices. The LHeC provides a very clean environment that allows for easy identification of these final states, in contrast to hadronic colliders where the overwhelming backgrounds and high pile-up render such searches incredibly challenging. We find that the LHeC provides a unique window of opportunity to detect scalar particles with masses between 10 and 30 GeV. In the Higgs Portal scenarios we can test the mixing angle squared, sin2α, as low as 10−5–10−7, with the exact value depending on the vacuum expectation value of the new scalar.Our results are also presented in a model-independent fashion in the lifetime-branching ratio and mass-branching ratio planes. We have found that exotic branching ratios of the Higgs boson at the sub-percent level can be probed, for the scalar decay length in the range 10−4 m ≲ cτ ≲ 10−1 m. The expected coverage of the parameter space largely exceeds the published sensitivity of the indirect reach at the high-luminosity Large Hadron Collider via the invisible Higgs branching ratio.

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
Junxing Pan ◽  
Jung-Hsin Chen ◽  
Xiao-Gang He ◽  
Gang Li ◽  
Jhih-Ying Su

AbstractIn this work, we study the potential of searching for triply charged Higgs boson originating from a complex Higgs quadruplet in the final state with at least three same-sign leptons. A detailed collider analysis of the SM backgrounds and signals is performed at a 100 TeV pp collider for the triply charged Higgs boson mass below 1 TeV and the Higgs quadruplet vacuum expectation value $$v_\Delta $$ v Δ ranging from $$1.5\times 10^{-9}~\text {GeV}$$ 1.5 × 10 - 9 GeV to $$1.3~\text {GeV}$$ 1.3 GeV and the mass splitting $$\Delta m$$ Δ m between the nearby states of the Higgs quadruplet satisfying $$|\Delta m|\lesssim 30~\text {GeV}$$ | Δ m | ≲ 30 GeV . About $$100~\text {fb}^{-1}$$ 100 fb - 1 of data are required at most for $$5\sigma $$ 5 σ discovery. We also revisit the sensitivity at the Large Hadron Collider (LHC) and find that $$5\sigma $$ 5 σ discovery of the triply charged Higgs boson below 1 TeV can be reached for a relatively small $$v_\Delta $$ v Δ . For example, if $$v_\Delta =10^{-6}~\text {GeV}$$ v Δ = 10 - 6 GeV and $$\Delta m=0$$ Δ m = 0 , the integrated luminosity of $$330~\text {fb}^{-1}$$ 330 fb - 1 is needed. But for a relatively large $$v_\Delta $$ v Δ , i.e., $$v_\Delta \gtrsim 10^{-3}~\text {GeV}$$ v Δ ≳ 10 - 3 GeV , the triply charged Higgs boson above about 800 GeV cannot be discovered even in the high-luminosity LHC era. For $$\Delta m>0$$ Δ m > 0 , the cascade decays are open and the sensitivity can be improved depending on the value of $$v_\Delta $$ v Δ .


2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Duarte Azevedo ◽  
Pedro Gabriel ◽  
Margarete Mühlleitner ◽  
Kodai Sakurai ◽  
Rui Santos

Abstract The Higgs invisible decay width may soon become a powerful tool to probe extensions of the Standard Model with dark matter candidates at the Large Hadron Collider. In this work, we calculate the next-to-leading order (NLO) electroweak corrections to the 125 GeV Higgs decay width into two dark matter particles. The model is the next-to-minimal 2-Higgs-doublet model (N2HDM) in the dark doublet phase, that is, only one doublet and the singlet acquire vacuum expectation values. We show that the present measurement of the Higgs invisible branching ratio, BR(H → invisible < 0.11), does not lead to constraints on the parameter space of the model at leading order. This is due to the very precise measurements of the Higgs couplings but could change in the near future. Furthermore, if NLO corrections are required not to be unphysically large, no limits on the parameter space can be extracted from the NLO results.


2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Yan Wang ◽  
A. Arhrib ◽  
R. Benbrik ◽  
M. Krab ◽  
B. Manaut ◽  
...  

Abstract We analyse a light charged Higgs boson in the 2-Higgs Doublet Model (2HDM) Type-I, when its mass satisfies the condition MH±< Mt + Mb and the parameter space is consistent with theoretical requirements of self-consistency as well as the latest experimental constraints from Large Hadron Collider (LHC) and other data. Over such a parameter space, wherein the Standard Model (SM)-like state discovered at the LHC in 2012 is the heaviest CP-even state of the 2HDM, it is found that the decay modes of the charged Higgs boson are dominated by H±→ W±(∗)h. Furthermore, the light neutral Higgs boson h dominantly decays into two photons. Under these conditions, we find that the production and decay process pp → H±h → W±(∗)hh → ℓνℓ + 4γ (ℓ = e, μ) is essentially background free. However, since the W±(∗) could be largely off-shell and the h state is very light, so that both the lepton coming from the former and the photons coming from the latter could be rather soft, we perform here a full Monte Carlo (MC) analysis at the detector level demonstrating that such a W± + 4γ signal is very promising, as it would be yielding significant excesses at the LHC with an integrated luminosity of L = 300 fb−1 at both $$ \sqrt{s} $$ s = 13 and 14 TeV.


1997 ◽  
Vol 12 (21) ◽  
pp. 1531-1535 ◽  
Author(s):  
Zhen Yun Fang ◽  
G. López Castro ◽  
J. Pestieau ◽  
J. L. M. Lucio

We assume the stability of the vacuum expectation value of the Higgs boson field under radiative corrections in the context of the standard electroweak theory. We find that this theory behaves as a good effective model already at cutoff energy scales as low as 0.7 TeV. This stability criterion allows us to predict mH=318±13 GeV for the Higgs boson mass.


2018 ◽  
Vol 182 ◽  
pp. 02119
Author(s):  
Liaoshan Shi

In this report, we present the latest ATLAS results on the measurement of the cross sections and couplings of the Higgs boson in the fermionic decay modes, H → μ+μ-, H → τ+τ- and H → bb. The searches are performed with proton-proton collision data delivered by the Large Hadron Collider during Run 1 and the first two years of Run 2 at √s = 7, 8 and 13 TeV.


2019 ◽  
Vol 34 (28) ◽  
pp. 1950230
Author(s):  
Zhaoxia Heng ◽  
Lin Guo ◽  
Pengqiang Sun ◽  
Wei Wei

Charged Higgs boson is a crucial prediction of new physics beyond the SM. In this work, we perform a comprehensive scan over the parameter space of NMSSM considering various experimental constraints including the direct search limits from the 13 TeV LHC, and consider the scenario that the next-to-lightest CP-even Higgs boson is SM-like. We find that the masses of charged Higgs bosons can be as light as 350 GeV, the lightest CP-even Higgs boson [Formula: see text] is predominantly singlet and can be as light as 48 GeV, and the lightest CP-odd Higgs boson [Formula: see text] is also singlet-dominated and can be as light as 82 GeV. The charged Higgs bosons mainly decay to [Formula: see text] or [Formula: see text], but the branching ratio of the exotic decays [Formula: see text] and [Formula: see text] can maximally reach 20% and 11%, respectively, which can be used to distinguish the NMSSM from MSSM. Such a heavy charged Higgs boson is inaccessible at the 13 TeV LHC with a luminosity of 36.1 fb[Formula: see text] and its detection needs higher energy and/or higher luminosity.


2020 ◽  
Vol 80 (10) ◽  
Author(s):  
Nobuhito Maru ◽  
Yoshiki Yatagai

AbstractGrand gauge–Higgs unification of five dimensional SU(6) gauge theory on an orbifold $$S^1/Z_2$$ S 1 / Z 2 with localized gauge kinetic terms is discussed. The Standard model (SM) fermions on one of the boundaries and some massive bulk fermions coupling to the SM fermions on the boundary are introduced, so that they respect an SU(5) symmetry structure. The SM fermion masses including top quark are reproduced by mild tuning the bulk masses and parameters of the localized gauge kinetic terms. Gauge coupling universality is not guaranteed by the presence of the localized gauge kinetic terms and it severely constrains the Higgs vacuum expectation value. Higgs potential analysis shows that the electroweak symmetry breaking occurs by introducing additional bulk fermions in simplified representations. The localized gauge kinetic terms enhance the magnitude of the compactification scale, which helps Higgs boson mass large. Indeed the observed Higgs boson mass 125 GeV is obtained.


1998 ◽  
Vol 13 (10) ◽  
pp. 753-757 ◽  
Author(s):  
ALI AL-NAGHMOUSH ◽  
MURAT ÖZER ◽  
M. O. TAHA

We impose the condition that the eigenvalues of the mass matrix in the shifted Lagrangian density be positive at ϕ=ϕ0, the vacuum expectation value of the scalar field. Using the one-loop effective potential of the standard model, this condition leads to an upper bound on the Higgs boson mass m H :m H <230 GeV, for a top quark mass of 175 GeV.


2013 ◽  
Vol 28 (02) ◽  
pp. 1330004 ◽  
Author(s):  
ALEKSANDR AZATOV ◽  
JAMISON GALLOWAY

In this review, we discuss methods of parsing direct information from collider experiments regarding the Higgs boson and describe simple ways in which experimental likelihoods can be consistently reconstructed and interfaced with model predictions in pertinent parameter spaces. We review prevalent scenarios for extending the electroweak symmetry breaking sector and emphasize their predictions for nonstandard Higgs phenomenology that could be observed in large hadron collider (LHC) data if naturalness is realized in particular ways. Specifically we identify how measurements of Higgs couplings can be used to imply the existence of new physics at particular scales within various contexts. The most dominant production and decay modes of the Higgs-like state observed in the early data sets have proven to be consistent with predictions of the Higgs boson of the Standard Model, though interesting directions in subdominant channels still exist and will require our careful attention in further experimental tests. Slightly anomalous rates in certain channels at the early LHC have spurred effort in model building and spectra analyses of particular theories, and we discuss these developments in some detail. Finally, we highlight some parameter spaces of interest in order to give examples of how the data surrounding the new state can most effectively be used to constrain specific models of weak scale physics.


2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Koichi Hamaguchi ◽  
Shihwen Hor ◽  
Natsumi Nagata

Abstract We construct a supersymmetric flipped SU(5) grand unified model that possesses an R symmetry. This R symmetry forbids dangerous non-renormalizable operators suppressed by a cut-off scale up to sufficiently large mass dimensions so that the SU(5)-breaking Higgs field develops a vacuum expectation value of the order of the unification scale along the F- and D-flat directions, with the help of the supersymmetry-breaking effect. The mass terms of the Higgs fields are also forbidden by the R symmetry, with which the doublet-triplet splitting problem is solved with the missing partner mechanism. The masses of right-handed neutrinos are generated by non-renormalizable operators, which then yield a light neutrino mass spectrum and mixing through the seesaw mechanism that are consistent with neutrino oscillation data. This model predicts one of the color-triplet Higgs multiplets to lie at an intermediate scale, and its mass is found to be constrained by proton decay experiments to be ≳ 5 × 1011 GeV. If it is ≲ 1012 GeV, future proton decay experiments at Hyper-Kamiokande can test our model in the p → π0μ+ and p → K0μ+ decay modes, in contrast to ordinary grand unified models where p → π0e+ or p → $$ {K}^{+}\overline{\nu} $$ K + ν ¯ is the dominant decay mode. This characteristic prediction for the proton decay branches enables us to distinguish our model from other scenarios.


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