Can the 750-GeV diphoton resonance be the singlet Higgs boson of custodial Higgs triplet model?

The observation of diphoton excess around the mass of 750 GeV in LHC Run-II motivates us to consider whether the singlet Higgs boson in the custodial Higgs triplet model can serve as a good candidate because an earlier study of comprehensive parameter scan shows that it can have the right mass in the viable mass spectra. By assuming the singlet Higgs mass at 750 GeV, its total width less than 50 GeV and imposing constraints from the LHC 8-TeV data, we identify an approximately linear region on the $(v_\Delta, \alpha)$ plane along which the exotic Higgs boson masses satisfy a specific hierarchy and have lower possible spectra, where $v_\Delta$ denotes the triplet vacuum expectation value and $\alpha$ is the mixing angle between the singlet Higgs boson and the standard model-like Higgs boson. Although the diphoton decay rate can be enhanced by charged Higgs bosons running in the loop in this region, it is mostly orders of magnitude smaller than that required for the observed production rate, except for the small $v_\Delta$ region when the diphoton fusion production mechanism becomes dominant. Nonetheless, this part of parameter space suffers from the problems of breakdown of perturbativity and large uncertainties in the photon parton distribution function of proton.Comment: 14 pages, 2 figures, and 2 tables; bugs in numerical calculations fixed, and discussions and conclusions changed; typo corrected; 16 pages, expanded with more detailed discussions, updated figures and tables, version to appear in the journa

The effects of social skills training on the prevention of perceived stress, depression, and social anxiety of Taiwanese graduate students in the United States

The purpose of this study was to determine the effects of an Banduraian-based group social skills training in the prevention of stress, depression, and social anxiety of Taiwanese graduate students in the U.S.;The subjects of this study were 60 Taiwanese students recruited at four seminars sponsored by the Taiwan Ministry of Education, which aimed to prepare students for future overseas study. Thirty subjects were randomly assigned to the experimental condition and were trained with social skills before they left for U.S. The other thirty subjects were assigned to the control group without any treatment.;It was hypothesized that: (1) There would be a significant difference at the.05 level in subjects receiving pre-arrival social skills training as contrast with subjects receiving no treatment in their level of stress, depression, and social anxiety at the posttest (1 week after treatment); (2) There would be a significant difference at the.05 level in subjects receiving pre-arrival social skills training as contrast with subjects receiving no treatment in their level of stress, depression, and social anxiety at the follow-up (1 to 2 month after subjects\u27 arrival in U.S.).;The results indicated that participation in an Banduraian-based group skills training course for Taiwanese graduate students did not have short term effects on their perceived stress, depression, and social anxiety. However, results demonstrated a general trend toward more positive outcomes. Although there was also no evidence for the effectiveness of social skills training in the prevention of future perceived depression and social anxiety, the analysis of followup data revealed that the effects of social skills training on prevention of perceived stress for Taiwanese graduate students was supported

Radiative corrections to Higgs couplings with weak gauge bosons in custodial multi-Higgs models

We calculate 1-loop radiative corrections to the $hZZ$ and $hWW$ couplings in models with next--to--simplest Higgs sectors satisfying the electroweak $\rho$ parameter equal to 1 at tree level: the Higgs singlet model, the two-Higgs doublet models, and the Georgi-Machacek model. Under theoretical and current experimental constraints, the three models have different correlations between the deviations in the $hZZ$ and $hWW$ couplings from the standard model predictions. In particular, we find for each model predictions with no overlap with the other two models.Comment: 5 pages, 1 figur

Modeling Time-dependent Responses of Piezoelectric Fiber Composite

The existence of polymer constituent in piezoelectric fiber composites (PFCs) could lead to significant viscoelastic behaviors, affecting overall performance of PFCs. High mechanical and electrical stimuli often generate significant amount of heat, increasing temperatures of the PFCs. At elevated temperatures, most materials, especially polymers show pronounced time-dependent behaviors. Predicting time-dependent responses of the PFCs becomes important to improve reliability in using PFCs. We study overall performance of PFCs having unidirectional piezoceramic fibers, such as PZT fibers, dispersed in viscoelastic polymer matrix. Two types of PFCs are studied, which are active fiber composites (AFCs) and macro fiber composites (MFCs). AFCs and MFCs consist of unidirectional PZT fibers dispersed in epoxy placed between two interdigitated electrode and kapton layers. The AFCs have a circular fiber cross-section while the MFCs have a square fiber cross-section. Finite element (FE) models of representative volume elements (RVEs) of active PFCs, having square and circular fiber cross-sections, are generated for composites with 20, 40, and 60 percent fiber contents. Two FE micromechanical models having one fiber embedded in epoxy matrix and five fibers placed in epoxy matrix are considered. A continuum 3D piezoelectric element in ABAQUS FE is used. A general time-integral function is applied for the mechanical, electrical, and piezoelectric properties in order to incorporate the time-dependent effect and histories of loadings. The effective properties of PZT-5A/epoxy and PZT-7A/LaRC-SI piezocomposites determined from the FE micromechanical models are compared to available experimental data and analytical solutions in the literature. Furthermore, the effect of viscoelastic behaviors of the LaRC-SI matrix at an elevated temperature on the overall electro-mechanical and piezoelectric constants are examined

New Insights on 30 Dor B Revealed by High-Quality Multi-wavelength Observations

The supernova remnant (SNR) 30 Dor B is associated with the \ion{H}{2} region ionized by the OB association LH99. The complex interstellar environment has made it difficult to study the physical structure of this SNR. We have used Hubble Space Telescope H$\alpha$ images to identify SNR shocks and deep Chandra X-ray observations to detect faint diffuse emission. We find that 30 Dor B hosts three zones with very different X-ray surface brightnesses and nebular kinematics that are characteristic of SNRs in different interstellar environments and/or evolutionary stages. The ASKAP 888 MHz map of 30 Dor B shows counterparts to all X-ray emission features except the faint halo. The ASKAP 888 MHz and 1420 MHz observations are used to produce a spectral index map, but its interpretation is complicated by the background thermal emission and the pulsar PSR J0537$-$6910's flat spectral index. The stellar population in the vicinity of 30 Dor B indicates a continuous star formation in the past 8--10 Myr. The observed very massive stars in LH99 cannot be coeval with the progenitor of 30 Dor B's pulsar. Adopting the pulsar's spin-down timescale, 5000 yr, as the age of the SNR, the X-ray shell would be expanding at $\sim$4000 km\,s$^{-1}$ and the post-shock temperature would be 1--2 orders of magnitude higher than that indicated by the X-ray spectra. Thus, the bright central region of 30 Dor B and the X-ray shell requires two separate SN events, and the faint diffuse X-ray halo perhaps other older SN events