Hidden-Sector Higgs Bosons at High-Energy Electron-Positron Colliders

The possibility of a scalar messenger that can couple the Standard Model (SM) to a hidden sector has been discussed in a variety of contexts in the literature in recent years. We consider the case that a new scalar singlet charged under an exotic spontaneously broken Abelian gauge symmetry mixes weakly with the SM Higgs resulting in two scalar mass states, one of which has heavily suppressed couplings to the SM particles. Previous phenomenological studies have focussed on potential signatures for such a model at the Large Hadron Collider (LHC). However, there are interesting regions of the parameter space in which the heavier Higgs state would be out of reach for LHC searches if its mass is greater than 1 TeV. We therefore investigate the discovery potential for such a particle at a 3 TeV electron-positron collider, which is motivated by the recent developments of the Compact Linear Collider (CLIC). We find that such an experiment could substantially extend our discovery reach for a heavy, weakly coupled Higgs boson, and we discuss three possible search channels.Comment: 14 pages, 8 Figures. Published as an LCD Not

A 3D radiative transfer framework IX. Time dependence

Context. Time-dependent, 3D radiation transfer calculations are important for the modeling of a variety of objects, from supernovae and novae to simulations of stellar variability and activity. Furthermore, time-dependent calculations can be used to obtain a 3D radiative equilibrium model structure via relaxation in time. Aims. We extend our 3D radiative transfer framework to include direct time dependence of the radiation field; i.e., the $\partial I/ \partial t$ terms are fully considered in the solution of radiative transfer problems. Methods. We build on the framework that we have described in previous papers in this series and develop a subvoxel method for the $\partial I/\partial t$ terms. Results. We test the implementation by comparing the 3D results to our well tested 1D time dependent radiative transfer code in spherical symmetry. A simple 3D test model is also presented. Conclusions. The 3D time dependent radiative transfer method is now included in our 3D RT framework and in PHOENIX/3D.Comment: A&A in press, 7 pages, 14 figure

Anxiety and Posttraumatic Stress Disorder in the Context of Human Brain Evolution:A Role for Theory in DSM-V?

The “hypervigilance, escape, struggle, tonic immobility”\ud evolutionarily hardwired acute peritraumatic response\ud sequence is important for clinicians to understand. Our\ud commentary supplements the useful article on human\ud tonic immobility (TI) by Marx, Forsyth, Gallup, Fusé and Lexington (2008). A hallmark sign of TI is peritraumatic\ud tachycardia, which others have documented as a\ud major risk factor for subsequent posttraumatic stress\ud disorder (PTSD). TI is evolutionarily highly conserved\ud (uniform across species) and underscores the need for\ud DSM-V planners to consider the inclusion of evolution\ud theory in the reconceptualization of anxiety and PTSD.\ud We discuss the relevance of evolution theory to the\ud DSM-V reconceptualization of acute dissociativeconversion\ud symptoms and of epidemic sociogenic disorder(epidemic “hysteria”). Both are especially in need of attention in light of the increasing threat of terrorism\ud against civilians. We provide other pertinent examples.\ud Finally, evolution theory is not ideology driven (and\ud makes testable predictions regarding etiology in “both\ud directions”). For instance, it predicted the unexpected\ud finding that some disorders conceptualized in DSM-IV-TR as innate phobias are conditioned responses and thus better conceptualized as mild forms of PTSD. Evolution\ud theory may offer a conceptual framework in\ud DSM-V both for treatment and for research on psychopathology.\u

Predicted and measured strain responses of isotropic panels to base excitation

The accuracy of classical linear theory for predicting acceleration and strain for cantilevered and Clamped-Free-Clamped-Free (C-F-C-F) panels excited through the base is studied. Aluminum, steel and titanium plates of various dimensions and thicknessess were vibration tested, using a broadband random signal applied through a shaker mounting fixture. The strains were measured at 9 locations on the cantilevered panels and at 5 locations on the C-F-C-F panels. Predictions were based on the Ritz method. The measured accelerations of the base were input to the analysis for the forcing function. Comparisons between predicted and measured strain acceleration spectra were within an average error of 20 percent for both the cantilevered and C-F-C-F panels

Renormalisation of supersymmetric gauge theory in the uneliminated component formalism

We show that the renormalisation of the N=1 supersymmetric gauge theory when working in the component formalism, without eliminating auxiliary fields and using a standard covariant gauge, requires a non-linear renormalisation of the auxiliary fields.Comment: 9 pages, including 4 figures. Plain TeX. Uses Harvmac and epsf; reference added and minor changes to Introductio

Lateral-directional stability and control characteristics of the Quiet Short-Haul Research Aircraft (QSRA)

The results are presented of flight experiments to determine the lateral-directional stability and control characteristics of the Quiet Short-Haul Research Aircraft (QSRA), an experimental aircraft designed to furnish information on various aerodynamic characteristics of a transport type of airplane that makes use of the upper-surface blown (USB) flap technology to achieve short takeoff and landing (STOL) performance. The flight program designed to acquire the data consisted of maneuvers produced by rudder and control-wheel inputs with the airplane in several configurations that had been proposed for landing approach and takeoff operation. The normal stability augmentation system was not engaged during these maneuvers. Time-history records from the maneuvers were analyzed with a parameter estimation procedure to extract lateral-directional stability and control derivatives. For one aircraft configuration in which the USB flaps were deflected 50 deg, several maneuvers were performed to determine the effects of varying the average angle of attack, varying the thrust coefficient, and setting the airplane's upper surface spoilers at a 13 deg symmetrical bias angle . The effects on the lateral characteristics of deflecting the spoilers were rather small and generally favorable. The data indicate that for one test, conducted at low thrust (a thrust coefficient of 0.38), compared with results from tests at thrust coefficients of 0.77 and larger, there was a significant decrease in the lateral control effectiveness, in the yaw damping and in the directional derivative. The directional derivative was also decreased (by about 30 percent) when the average angle of attack of the test was increased from 3 to 16 deg

Near-infrared light curves of type Ia supernovae

Aims. With our time-dependent model atmosphere code PHOENIX, our goal is to simulate light curves and spectra of hydrodynamical models of all types of supernovae. In this work, we simulate near-infrared light curves of SNe Ia and confirm the cause of the secondary maximum. Methods. We apply a simple energy solver to compute the evolution of an SN Ia envelope during the free expansion phase. Included in the solver are energy changes due to expansion, the energy deposition of {\gamma}-rays and interaction of radiation with the material. Results. We computed theoretical light curves of several SN Ia hydrodynamical models in the I, J, H, and K bands and compared them to the observed SN Ia light curves of SN 1999ee and SN 2002bo. By changing a line scattering parameter in time, we obtained quite reasonable fits to the observed near-infrared light curves. This is a strong hint that detailed NLTE effects in IR lines have to be modeled, which will be a future focus of our work. Conclusions. We found that IR line scattering is very important for the near-infrared SN Ia light curve modeling. In addition, the recombination of Fe III to Fe II and of Co III to Co II is responsible for the secondary maximum in the near-infrared bands. For future work the consideration of NLTE for all lines (including the IR subordinate lines) will be crucial.Comment: 5 pages, 12 figures, A&A in pres

A simple model to estimate atmospheric concentrations of aerosol chemical species based on snow core chemistry at Summit, Greenland

A simple model is presented to estimate atmospheric concentrations of chemical species that exist primarily as aerosols based on snow core/ice core chemistry at Summit, Greenland. The model considers the processes of snow, fog, and dry deposition. The deposition parameters for each of the processes are estimated for SO42− and Ca2+ and are based on experiments conducted during the 1993 and 1994 summer field seasons. The seasonal mean atmospheric concentrations are estimated based on the deposition parameters and snow cores obtained during the field seasons. The ratios of the estimated seasonal mean airborne concentration divided by the measured mean concentration ( ) for SO42− over the 1993 and 1994 field seasons are 0.85 and 0.95, respectively. The ratios for Ca2+ are 0.45 and 0.90 for the 1993 and 1994 field seasons. The uncertainties in the estimated atmospheric concentrations range from 30% to 40% and are due to variability in the input parameters. The model estimates the seasonal mean atmospheric SO42− and Ca2+ concentrations to within 15% and 55%, respectively. Although the model is not directly applied to ice cores, the application of the model to ice core chemical signals is briefly discussed