131 research outputs found
Testing Higgs models via the vertex by a recoil method at the International Linear Collider
In general, charged Higgs bosons appear in non-minimal Higgs models.
The vertex is known to be related to the violation of the
global symmetry (custodial symmetry) in the Higgs sector. Its magnitude
strongly depends on the structure of the exotic Higgs models which contain
higher isospin representations such as triplet Higgs bosons. We study
the possibility of measuring the vertex via single charged
Higgs boson production associated with the boson at the International
Linear Collider (ILC) by using the recoil method. The feasibility of the signal
is analyzed assuming the polarized
electron and positron beams and the expected detector performance for the
resolution of the two-jet system at the ILC. The background events can be
reduced to a considerable extent by imposing the kinematic cuts even if we take
into account the initial state radiation. For a relatively light charged Higgs
boson whose mass is in the region of 120-130 GeV , the vertex would be precisely testable especially
when the decay of is lepton specific. The exoticness of the extended
Higgs sector can be explored by using combined information for this vertex and
the rho parameter.Comment: 22 pages, 23 figure
Radiative corrections to electroweak parameters in the Higgs triplet model and implication with the recent Higgs boson searches
We study radiative corrections to the electroweak parameters in the Higgs
model with the Y=1 triplet field, which is introduced in the scenario of
generating neutrino masses based on the so-called type II seesaw mechanism. In
this model, the rho parameter deviates from unity at the tree level.
Consequently, the electroweak sector of the model is described by the four
input parameters such as , , and
. We calculate the one loop contribution to the W boson mass as
well as to the rho parameter in order to clarify the possible mass spectrum of
the extra Higgs bosons under the constraint from the electroweak precision
data. We find that the hierarchical mass spectrum among ,
and (or ) is favored by the precision data especially for the case of
, where , , and
are the doubly-charged, singly-charged, CP-odd and CP-even Higgs bosons
mainly originated from the triplet field. We also discuss phenomenological
consequences of such a mass spectrum with relatively large mass splitting. The
decay rate of the Higgs boson decay into two photons is evaluated under the
constraint from the electroweak precision data, regarding the recent Higgs
boson searches at the CERN LHC.Comment: 17 pages, 23 figures, version published in PRD, title slightly
modifie
Models of Yukawa interaction in the two Higgs doublet model, and their collider phenomenology
Possible models of Yukawa interaction are discussed in the two Higgs doublet
model (THDM) under the discrete symmetry imposed to avoid the flavor changing
neutral current at the leading order. It is known that there are four types of
such models corresponding to the possible different assignment of charges for
the discrete symmetry on quarks and leptons. We first examine decay properties
of Higgs bosons in each type of the models, and summarize constraints on the
models from current experimental data. We then shed light on the differences
among these models in collider phenomenology. In particular, we mainly discuss
so-called the Type-II THDM and the Type-X THDM. The Type-II THDM corresponds to
the model with the same Yukawa interaction as the minimal supersymmetric
standard model (MSSM). On the other hand, in the Type-X THDM, additional Higgs
bosons can predominantly decay into leptons. This scenario may be interesting
because of the motivation for a light charged Higgs boson scenario such as in
the TeV scale model of neutrino, dark matter and baryogenesis. We study how we
can distinguish the Type-X THDM from the MSSM at the Large Hadron Collider and
the International Linear Collider.Comment: 33 pages, 41 eps files, version accepted for publication in Physical
Review
The antecedents of biliary cancer: a primary care case–control study in the United Kingdom
In a case–control study using a large UK primary care database, we found that non-steroidal anti-inflammatory drugs had no protective effect against biliary carcinomas (cholangiocarcinoma and gall bladder cancer). Increased risks were observed for cigarette smoking, diabetes, gallstone disease and obesity
Decoupling property of the supersymmetric Higgs sector with four doublets
In supersymmetric standard models with multi Higgs doublet fields,
selfcoupling constants in the Higgs potential come only from the D-terms at the
tree level. We investigate the decoupling property of additional two heavier
Higgs doublet fields in the supersymmetric standard model with four Higgs
doublets. In particular, we study how they can modify the predictions on the
quantities well predicted in the minimal supersymmetric standard model (MSSM),
when the extra doublet fields are rather heavy to be measured at collider
experiments. The B-term mixing between these extra heavy Higgs bosons and the
relatively light MSSM-like Higgs bosons can significantly change the
predictions in the MSSM such as on the masses of MSSM-like Higgs bosons as well
as the mixing angle for the two light CP-even scalar states. We first give
formulae for deviations in the observables of the MSSM in the decoupling region
for the extra two doublet fields. We then examine possible deviations in the
Higgs sector numerically, and discuss their phenomenological implications.Comment: 26 pages, 24 figures, text sligtly modified,version to appear in
Journal of High Energy Physic
A Novel Adaptive Method for the Analysis of Next-Generation Sequencing Data to Detect Complex Trait Associations with Rare Variants Due to Gene Main Effects and Interactions
There is solid evidence that rare variants contribute to complex disease etiology. Next-generation sequencing technologies make it possible to uncover rare variants within candidate genes, exomes, and genomes. Working in a novel framework, the kernel-based adaptive cluster (KBAC) was developed to perform powerful gene/locus based rare variant association testing. The KBAC combines variant classification and association testing in a coherent framework. Covariates can also be incorporated in the analysis to control for potential confounders including age, sex, and population substructure. To evaluate the power of KBAC: 1) variant data was simulated using rigorous population genetic models for both Europeans and Africans, with parameters estimated from sequence data, and 2) phenotypes were generated using models motivated by complex diseases including breast cancer and Hirschsprung's disease. It is demonstrated that the KBAC has superior power compared to other rare variant analysis methods, such as the combined multivariate and collapsing and weight sum statistic. In the presence of variant misclassification and gene interaction, association testing using KBAC is particularly advantageous. The KBAC method was also applied to test for associations, using sequence data from the Dallas Heart Study, between energy metabolism traits and rare variants in ANGPTL 3,4,5 and 6 genes. A number of novel associations were identified, including the associations of high density lipoprotein and very low density lipoprotein with ANGPTL4. The KBAC method is implemented in a user-friendly R package
- …