63 research outputs found
Trilinear Higgs couplings in the two Higgs doublet model with CP violation
We carry out a detailed analysis of the general two Higgs doublet model with
CP violation. We describe two different parametrizations of this model, and
then study the Higgs boson masses and the trilinear Higgs couplings for these
two parametrizations. Within a rather general model, we find that the trilinear
Higgs couplings have a significant dependence on the details of the model, even
when the lightest Higgs boson mass is taken to be a fixed parameter. We include
radiative corrections in the one-loop effective potential approximation in our
analysis of the Higgs boson masses and the Higgs trilinear couplings. The
one-loop corrections to the trilinear couplings of the two Higgs doublet model
also depend significantly on the details of the model, and can be rather large.
We study quantitatively the trilinear Higgs couplings, and show that these
couplings are typically several times larger than the corresponding Standard
Model trilinear Higgs coupling in some regions of the parameter space. We also
briefly discuss the decoupling limit of the two Higgs doublet model.Comment: 23 pages, 15 figures. v2: References added, version to appear in PR
Constraining the Two-Higgs-Doublet-Model parameter space
We confront the Two-Higgs-Doublet Model with a variety of experimental
constraints as well as theoretical consistency conditions. The most
constraining data are the \bar B\to X_s\gamma decay rate (at low values of
M_{H^\pm}), and \Delta\rho (at both low and high M_{H^\pm}). We also take into
account the B\bar B oscillation rate and R_b, or the width \Gamma(Z\to b\bar b)
(both of which restrict the model at low values of \tan\beta), and the
B^-\to\tau\nu_\tau decay rate, which restricts the model at high \tan\beta and
low M_{H^\pm}. Furthermore, the LEP2 non-discovery of a light, neutral Higgs
boson is considered, as well as the muon anomalous magnetic moment. Since
perturbative unitarity excludes high values of \tan\beta, the model turns out
to be very constrained. We outline the remaining allowed regions in the
\tan\beta-M_{H^\pm} plane for different values of the masses of the two
lightest neutral Higgs bosons, and describe some of their properties.Comment: 17 pages, 17 figure
Neutral Higgs-pair production at Linear Colliders within the general 2HDM: quantum effects and triple Higgs boson self-interactions
The pairwise production of neutral Higgs bosons is analyzed in the context of
the future linear colliders, such as the ILC and CLIC, within the general
Two-Higgs-Doublet Model (2HDM). The corresponding cross-sections are computed
at the one-loop level in full compliance with the current phenomenological
bounds and the stringent theoretical constraints inherent to the consistency of
the model. We uncover regions across the 2HDM parameter space, mainly for low
tan\beta near 1 and moderate values of the relevant lambda_5 parameter, wherein
the radiative corrections to the Higgs-pair production cross sections can
comfortably reach 50% This behavior can be traced back to the enhancement
capabilities of the trilinear Higgs self-interactions -- a trademark feature of
the 2HDM, with no counterpart in the Minimal Supersymmetric Standard Model.
Interestingly enough, the quantum effects are positive for energies around 500
GeV, thereby producing a significant enhancement in the expected number of
events precisely around the fiducial startup energy of the ILC. The Higgs-pair
production rates can be substantial, typically amounting to a few thousand
events per 500 inverse femtobarn of integrated luminosity. In contrast, the
corrections are negative in the highest energy range (1 TeV). We also compare
the exclusive pairwise production of Higgs bosons with the inclusive gauge
boson fusion channels leading to 2H+X finals states, and also with the
exclusive triple Higgs boson production. We find that these multiparticle final
states can be highly complementary in the overall Higgs bosons search strategy.Comment: 42 pages, 23 figures, 10 tables. Accepted in Phys. Rev. D (the
published version is shorter
Probing the scalar-pseudoscalar mixing in the 125 GeV Higgs particle with current data
LHC has found hints for a Higgs particle of 125 GeV. We investigate the
possibility that such a particle is a mixture of scalar and pseudoscalar
states. For definiteness, we concentrate on a two Higgs doublet model with
explicit CP violation and soft Z2 violation. Including all Higgs production
mechanisms, we determine the current constraints obtained by comparing h ->
gamma gamma with h -> V V*, and comment on the information which can be gained
by measurements of h -> b \bar{b}. We find bounds |s_2| < 0.83 at one sigma,
where |s_2|=0 (|s_2|=1) corresponds to a pure scalar (pure pseudoscalar) state.Comment: 12 pages, 4 figure
Monitoring Breast Cancer Response to Neoadjuvant Chemotherapy Using Ultrasound Strain Elastography
© 2019 The Authors Strain elastography was used to monitor response to neoadjuvant chemotherapy (NAC) in 92 patients with biopsy-proven, locally advanced breast cancer. Strain elastography data were collected before, during, and after NAC. Relative changes in tumor strain ratio (SR) were calculated over time, and responder status was classified according to tumor size changes. Statistical analyses determined the significance of changes in SR over time and between response groups. Machine learning techniques, such as a naïve Bayes classifier, were used to evaluate the performance of the SR as a marker for Miller-Payne pathological endpoints. With pathological complete response (pCR) as an endpoint, a significant difference (P < .01) in the SR was observed between response groups as early as 2 weeks into NAC. Naïve Bayes classifiers predicted pCR with a sensitivity of 84%, specificity of 85%, and area under the curve of 81% at the preoperative scan. This study demonstrates that strain elastography may be predictive of NAC response in locally advanced breast cancer as early as 2 weeks into treatment, with high sensitivity and specificity, granting it the potential to be used for active monitoring of tumor response to chemotherapy
Probing the charged Higgs boson at the LHC in the CP-violating type-II 2HDM
We present a phenomenological study of a CP-violating two-Higgs-doublet Model
with type-II Yukawa couplings at the Large Hadron Collider (LHC). In the light
of recent LHC data, we focus on the parameter space that survives the current
and past experimental constraints as well as theoretical bounds on the model.
Once the phenomenological scenario is set, we analyse the scope of the LHC in
exploring this model through the discovery of a charged Higgs boson produced in
association with a W boson, with the former decaying into the lightest neutral
Higgs and a second W state, altogether yielding a b\bar b W^+W^- signature, of
which we exploit the W^+W^- semileptonic decays.Comment: 37 pages, 16 figures; v2 updated treatment of LHC constraint
Real-time and non-invasive measurements of cell mechanical behaviour with optical coherence phase microscopy
There is an unmet need in tissue engineering for non-invasive, label-free monitoring of cell mechanical behaviour in their physiological environment. Here, we describe a novel optical coherence phase microscopy (OCPM) set-up which can map relative cell mechanical behaviour in monolayers and 3D systems non-invasively, and in real-time. 3T3 and MCF-7 cells were investigated, with MCF-7 demonstrating an increased response to hydrostatic stimulus indicating MCF-7 being softer than 3T3, demonstrating the ability to provide qualitative data on cell mechanical behaviour. Quantitative measurements of 6% agarose beads have been taken with commercial Cell Scale Microsquisher® system demonstrating that their mechanical properties are in the same order of magnitude of cells, indicating that this is an appropriate test sample for the novel method desctibed
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