scholarly journals Sensitivity to invisible scalar decays at CLIC

2021 ◽  
Vol 136 (2) ◽  
Author(s):  
K. Mekala ◽  
A. F. Zarnecki ◽  
B. Grzadkowski ◽  
M. Iglicki
Keyword(s):  
Higgs Boson ◽  
Cross Section ◽  
Branching Ratio ◽  
Detector Response ◽  
Dark Sector ◽  
Mixing Angle ◽  
Associated Production ◽  
Neutral Scalar ◽  
Invisible Decays ◽  
Higgs Portal

AbstractWe studied the possibility of constraining production of new scalar particles at CLIC running at 380 GeV and 1.5 TeV, assuming the associated production of Higgs-like neutral scalar with $$\mathrm{Z}{}{} $$ Z boson and its invisible decays. The analysis is based on the Whizard event generation and fast simulation of the CLIC detector response with Delphes. We considered $${\mathrm{e}{}{}}^{+} {\mathrm{e}{}{}}^{-} $$ e + e - background processes but also relevant $$\upgamma {}{} \upgamma {}{} $$ γ γ and $$\upgamma {}{} \mathrm{e}{}{} ^{\pm }$$ γ e ± interactions. The approach consisting of a two-step analysis was used to optimise separation between signal and background processes. First, a set of preselection cuts was applied; then, multivariate analysis methods were employed to optimise the significance of observations. We first estimated the expected limits on the invisible decays of the 125 GeV Higgs boson, which were then extended to the cross section limits for production of an additional neutral scalar, assuming its invisible decays, as a function of its mass. Extracted model-independent branching ratio and cross section limits were then interpreted in the framework of the Higgs-portal models to set limits on the mixing angle between the SM-like Higgs boson and the new scalar of the “dark sector”.

Prospects for Observing $t\bar tH$ at Run II: A discovery mode for the Higgs boson?

2001 ◽  
Vol 16 (supp01a) ◽  
pp. 308-310 ◽  
Author(s):  
J. Goldstein ◽  
C. S. Hill ◽  
J. Incandela ◽  
Stephen Parke ◽  
D. Rainwater ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Cross Section ◽  
Top Quark ◽  
Production Cross Section ◽  
Production Cross ◽  
Branching Ratio ◽  
Higgs Bosons ◽  
Standard Model Higgs Boson ◽  
High Luminosity ◽  
Associated Production

The production of a Standard Model Higgs boson in association with a top quark pair at the upcoming high luminosity run (15 fb -1 integreted luminosity) of the Fermilab Tevatron [Formula: see text] is revisited. For Higgs masses below 140 GeV we demonstrate that the production cross section times branching ratio for [Formula: see text] decays yields a significant number of events and that this mode is competitive with and complementary to the searches using [Formula: see text], ZH associated production. For higher mass Higgs bosons the H → W+ W- decays are more difficult but have the potential to provide a few spectacular events.

scholarly journals Higgs boson production cross-section measurements and their EFT interpretation in the $$4\ell $$ decay channel at $$\sqrt{s}=$$13 TeV with the ATLAS detector

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Cross Section ◽  
Decay Channel ◽  
Branching Ratio ◽  
Proton Collision ◽  
Boson Production ◽  
Theory Approach ◽  
Higgs Boson Production ◽  
The Standard Model

AbstractHiggs boson properties are studied in the four-lepton decay channel (where lepton = e, $$\mu $$ μ ) using 139 $$\hbox {fb}^{-1}$$ fb - 1 of proton–proton collision data recorded at $$\sqrt{s}=$$ s = 13 TeV by the ATLAS experiment at the Large Hadron Collider. The inclusive cross-section times branching ratio for $$H\rightarrow ZZ^*$$ H → Z Z ∗ decay is measured to be $$1.34 \pm 0.12$$ 1.34 ± 0.12  pb for a Higgs boson with absolute rapidity below 2.5, in good agreement with the Standard Model prediction of $$1.33 \pm 0.08$$ 1.33 ± 0.08  pb. Cross-sections times branching ratio are measured for the main Higgs boson production modes in several exclusive phase-space regions. The measurements are interpreted in terms of coupling modifiers and of the tensor structure of Higgs boson interactions using an effective field theory approach. Exclusion limits are set on the CP-even and CP-odd ‘beyond the Standard Model’ couplings of the Higgs boson to vector bosons, gluons and top quarks.

scholarly journals ASSOCIATED PRODUCTION OF THE CHARGED HIGGS BOSON AND SINGLE TOP QUARK AT THE LHC

2009 ◽  
Vol 24 (02) ◽  
pp. 143-150 ◽  
Author(s):  
YAO-BEI LIU ◽  
JIE-FEN SHEN
Keyword(s):  
Higgs Boson ◽  
Cross Section ◽  
Top Quark ◽  
Production Cross ◽  
Hadron Collider ◽  
Charged Higgs Boson ◽  
Cern Large Hadron Collider ◽  
Associated Production ◽  
Single Top ◽  
Charged Higgs

The left–right twin Higgs (LRTH) model predicts the existence of the charged Higgs ϕ±. In this paper, we study the production of the charged Higgs boson ϕ- with single top quark via the process bg → tϕ- at the CERN Large Hadron Collider (LHC). The numerical results show that the production cross-section can reach the level of 10 pb in the reasonable parameter space of the LRTH model. We expect that, as long as it is not too heavy, the possible signatures of the heavy charged Higgs boson ϕ-> might be detected via the decay mode [Formula: see text] at the LHC experiments.

scholarly journals Higgs portal to dark matter and $$B\rightarrow K^{(*)}$$ decays

2020 ◽  
Vol 80 (7) ◽  
Author(s):  
Aliaksei Kachanovich ◽  
Ulrich Nierste ◽  
Ivan Nišandžić
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Decay Rates ◽  
Dark Sector ◽  
Mixing Angle ◽  
Decay Modes ◽  
Simultaneous Study ◽  
Belle Ii ◽  
Displaced Vertex ◽  
Higgs Portal

Abstract We consider a Higgs portal model in which the 125-GeV Higgs boson mixes with a light singlet mediator $$h_2$$h2 coupling to particles of a Dark Sector and study potential $$b\rightarrow s h_2$$b→sh2 decays in the Belle II experiment. Multiplying the gauge-dependent off-shell Standard-Model b-s-Higgs vertex with the sine of the Higgs mixing angle does not give the correct b-s-$$h_2$$h2 vertex. We clarify this issue by calculating the b-s-$$h_2$$h2 vertex in an arbitrary $$R_\xi $$Rξ gauge and demonstrate how the $$\xi $$ξ dependence cancels from physical decay rates involving an on-shell or off-shell $$h_2$$h2. Then we revisit the $$b\rightarrow s h_2$$b→sh2 phenomenology and point out that a simultaneous study of $$B\rightarrow K^* h_2$$B→K∗h2 and $$B\rightarrow K h_2$$B→Kh2 helps to discriminate between the Higgs portal and alternative models of the Dark Sector. We further advocate for the use of the $$h_2$$h2 lifetime information contained in displaced-vertex data with $$h_2$$h2 decaying back to Standard-Model particles to better constrain the $$h_2$$h2 mass or to reveal additional $$h_2$$h2 decay modes into long-lived particles.

scholarly journals Searches for MSSM Higgs Bosons with the DELPHI Detector up to $\sqrt{s} = 209~{\rm GeV}$

2001 ◽  
Vol 16 (supp01b) ◽  
pp. 813-815
Author(s):  
◽  
MARCEL STANITZKI
Keyword(s):  
Higgs Boson ◽  
Branching Ratio ◽  
Mass Range ◽  
Higgs Bosons ◽  
Neutral Higgs Boson ◽  
Centre Of Mass ◽  
Confidence Levels ◽  
Delphi Detector ◽  
Delphi Experiment ◽  
Invisible Decays

Searches for hA pair production and hZ production have been performed. Special emphasis has been put on searches, in which the Higgs can decay invisibly into neutralinos. The data collected by the DELPHI experiment at centre-of-mass energies between 191.6 and 201.7 Gev for the year 1999 and between 201.7 and 209.0 Gev for the ongoing data taking in 2000 has been used. These analyses are used, in combination with our results at lower energies, to set 95% confidence levels on the existence of a light neutral Higgs Boson h and a neutral pseudoscalar Higgs Boson A in a mass range of 85-115 GeV/c 2. Combining the searches for visible and invisible Higgs decays allows to obtain 95% confidence levels on the existance of h independent of the branching ratio into invisible decays, if the visible decays are taken to be the SM ones. The MSSM parameter space excluded by these searches has been determined.

scholarly journals The Higgs boson decays with the lepton flavor violation

2018 ◽  
Vol 33 (17) ◽  
pp. 1850103 ◽  
Author(s):  
O. M. Boyarkin ◽  
G. G. Boyarkina ◽  
D. S. Vasileuskaya
Keyword(s):  
Higgs Boson ◽  
Branching Ratio ◽  
Vacuum Expectation ◽  
Theoretical Expression ◽  
Symmetric Model ◽  
Third Order ◽  
Mixing Angle ◽  
Neutrino Sector ◽  
Lepton Flavor ◽  
Decay Widths

Within the left–right symmetric model (LRM), the decays [Formula: see text] where [Formula: see text] is an analog of the Standard Model Higgs boson, are considered. The widths of this decays are found in the third-order of the perturbation theory. Since the main contribution to the decay widths is caused by the diagram with the light and heavy neutrinos in the virtual state, then investigation of this decays could shed light upon the neutrino sector structure. The obtained decay widths critically depend on the charged gauge bosons mixing angle [Formula: see text] and the heavy–light neutrinos mixing angle [Formula: see text]. The LRM predicts the values of these angles as functions of the vacuum expectation values [Formula: see text] and [Formula: see text]. Using the results of the existing experiments, on looking for the additional charged gauge boson [Formula: see text] and on measuring the electroweak [Formula: see text] parameter, gives [Formula: see text] However, even using the upper bounds on [Formula: see text] and [Formula: see text], one does not manage to get the upper experimental bound on the branching ratio [Formula: see text] being equal to [Formula: see text]. The theoretical expression proves to be on two orders of magnitude less than [Formula: see text].

A SEARCH FOR HIGGS DECAYS TO WW* AT DØ

2005 ◽  
Vol 20 (15) ◽  
pp. 3297-3301
Author(s):  
◽  
AMBER JENKINS
Keyword(s):  
Higgs Boson ◽  
Cross Section ◽  
Confidence Level ◽  
Production Cross Section ◽  
Production Cross ◽  
Branching Ratio ◽  
Final States ◽  
Theoretical Predictions ◽  
Integrated Luminosity

A search for the Higgs boson in the channels [Formula: see text] at DØ is described. The data, corresponding to an integrated luminosity of up to 177 pb-1, are compared to theoretical predictions. No excess of events above the expected background is observed in any of the leptonic final states. Limits on the production cross-section times branching ratio, σ × BR(H → WW*), are therefore set at the 95% Confidence Level.

Search for New Particles Decaying into $b \bar{b}$ Associated with W± Bosons at Tevatron

2005 ◽  
Vol 20 (15) ◽  
pp. 3294-3296
Author(s):  
◽  
Yoshio Ishizawa
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Cross Section ◽  
Production Cross ◽  
W Bosons ◽  
Branching Ratio ◽  
Standard Model Higgs Boson ◽  
Upper Limit ◽  
The Standard Model ◽  
New Particles

We present searches for new particles decaying into [Formula: see text] and produced in association with W± bosons in [Formula: see text] collisions at [Formula: see text]. The searches focus on the Standard Model Higgs boson or Technicolor particle decaying into [Formula: see text] using approximately 162 pb-1 of the dataset accumulated by the Collider Detector at Fermilab. The number of events and mass distribution are consistent with the Standard Model expectations and we set a 95% confidence level upper limit on the production cross section times branching ratio as a function of the new particle mass.

Search for New Physics with High Mass Tau Pairs in CDF Run II

2005 ◽  
Vol 20 (15) ◽  
pp. 3287-3289
Author(s):  
Zongru Wan
Keyword(s):  
Higgs Boson ◽  
Cross Section ◽  
Branching Ratio ◽  
New Physics ◽  
Mass Region ◽  
High Mass ◽  
Significant Excess ◽  
Upper Limits ◽  
Tau Pairs ◽  
Low Mass

We present the results of a search for new particles decaying to tau pairs. Hypothetical particles, such as Z′ and MSSM Higgs boson A can potentially produce such pairs. The low-mass region, dominated by Z → ττ, is used as a control. No significant excess events over the estimated backgrounds is observed in the high-mass region, and we set upper limits on the cross section times branching ratio as a function of the Z′ and A mass.

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