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

Test instrumentation evaluates electrostatic hazards in fluid system

RJ-1 fuel surface potential is measured with a probe to determine the degree of hazard originating from static electricity buildup in the hydraulic fluid. The probe is mounted in contact with the fluid surface and connected to an electrostatic voltmeter

Some Applications of Detailed Wind Profile Data to Launch Vehicle Response Problems

The response of a launch vehicle to a number of detailed wind profiles has been determined. The wind profiles were measured by two techniques which are briefly described. One of these techniques uses an angle-of-attack sensor in conjunction with guidance data to measure the wind profile traversed by some particular launch vehicle. The other wind-measuring technique is a photographic triangulation method, whereby two cameras take simultaneous pictures of a vertical trail of smoke left by a launch vehicle or sounding rocket. The response of a vehicle flying these detailed profiles is compared with the response of the same vehicle flying through balloon-measured profiles. The response to the detailed wind profiles, relative t o the balloon-measured profiles, is characterized by the large excitation of the rigid pitch and elastic bending modes. This is found to cause higher loads on the launch vehicle structure. Established design criteria which utilize balloon measured wind profiles have arbitrarily accounted-for this increased load by adding a load due to some type of discrete gust

The Dependency of Penetration on the Momentum Per Unit Area of the Impacting Projectile and the Resistance of Materials to Penetration

The results of this investigation indicate that the penetration of projectiles into quasi-infinite targets can be correlated as a function of the maximum momentum per unit area possessed by the projectiles. The penetration of projectiles into aluminum, copper, and steel targets was found to be a linear function while the penetration into lead targets was a nonlinear function of the momentum per unit area of the impacting projectiles. Penetration varied inversely as the projectile density and the elastic modulus of the target material for a given projectile momentum per unit area. Crater volumes were found to be a linear function of the kinetic energy of the projectile, the greater volumes being obtained in the target materials which had the lowest yield strength and the lowest speed of sound

Complexation of Secondary Amides to Chromium(III): the X-Ray Structure of a Molecule with Two Modes of Monodentate Organic Amide Co-ordination

The X-ray crystal structure of the dimer [Cr{H(chba-Et)}(py)_2]_(2)·2py [H_(4)(chba-Et)= 1,2-bis(3,5-dichloro-2-hydroxybenzamido) ethane, py = pyridine] establishes, for the first time, the existence of N-co-ordination of an organic amide to Cr^III, the N-atom and carbonyl O-atom of two separate amide groups being co-ordinated to each Cr^III centre [Cr–N 2.030(6) and Cr–O 1.976(5)Å]; the potentially tetra-anionic chelating ligand leads to a variety of co-ordination modes

Reflection high-energy electron diffraction studies of the growth of lnAs/Ga_(1-x)In_xSb strained-layer superlattices

We have used reflection high‐energy electron diffraction to study the surface periodicity of the growth front of InAs/GaInSb strained‐layer superlattices (SLSs). We found that the apparent surface lattice spacing reproducibly changed during layers which subsequent x‐ray measurements indicated were coherently strained. Abrupt changes in the measured streak spacings were found to be correlated to changes in the growth flux. The profile of the dynamic streak spacing was found to be reproducible when comparing consecutive periods of a SLSs or different SLSs employing the same shuttering scheme at the InAs/GaInSb interface. Finally, when the interface shuttering scheme was changed, it was found that the dynamic streak separation profile also changed. Large changes in the shuttering scheme led to dramatic differences in the streak separation profile, and small changes in the shuttering scheme led to minor changes in the profile. In both cases, the differences in the surface periodicity profile occurred during the parts of the growth where the incident fluxes differed

Type II superlattices for infrared detectors and devices

Superlattices consisting of combinations of III-V semiconductors with type II band alignments are of interest for infrared applications because their energy gaps can be made smaller than those of any 'natural' III-V compounds. Specifically, it has been demonstrated that both InSb/InAsxSb1-x superlattices and Ga1-xInxSb/InAs superlattices can possess energy gaps in the 8-14 mu m range. The efforts have focused on the Ga1-xInxSb/InAs system because of its extreme broken gap band alignment, which results in narrow energy gaps for very short superlattice periods. The authors report the use of in situ chemical doping of Ga1-xInxSb/InAs superlattices to fabricate p-n photodiodes. These diodes display a clear photovoltaic response with a threshold near 12 mu m. They have also attained outstanding structural quality in Ga1-xInxSb/InAs superlattices grown on radiatively heated GaSb substrates. Cross-sectional transmission electron microscope images of these superlattices display no dislocations, while high resolution X-ray diffraction scans reveal sharp high-order superlattice satellites and strong Pendellosung fringes

Does the bracket-ligature combination affect the amount of orthodontic space closure over three months? A randomized controlled trial

OBJECTIVE: To investigate the effect of bracket-ligature combination on the amount of orthodontic space closure over three months. DESIGN: Randomized clinical trial with three parallel groups. SETTING: A hospital orthodontic department (Chesterfield Royal Hospital, UK). PARTICIPANTS: Forty-five patients requiring upper first premolar extractions. METHODS: Informed consent was obtained and participants were randomly allocated into one of three groups: (1) conventional pre-adjusted edgewise brackets and elastomeric ligatures; (2) conventional pre-adjusted edgewise brackets and Super Slick((R)) low friction elastomeric ligatures; (3) Damon 3MX((R)) passive self-ligating brackets. Space closure was undertaken on 0.019x0.025-inch stainless steel archwires with nickel-titanium coil springs. Participants were recalled at four weekly intervals. Upper alginate impressions were taken at each visit (maximum three). The primary outcome measure was the mean amount of space closure in a 3-month period. RESULTS: A one-way ANOVA was undertaken [dependent variable: mean space closure (mm); independent variable: group allocation]. The amount of space closure was very similar between the three groups (1 mm per 28 days); however, there was a wide variation in the rate of space closure between individuals. The differences in the amount of space closure over three months between the three groups was very small and non-significant (P = 0.718). CONCLUSION: The hypothesis that reducing friction by modifying the bracket/ligature interface increases the rate of space closure was not supported. The major determinant of orthodontic tooth movement is probably the individual patient response

Long distance quantum teleportation in a quantum relay configuration

A long distance quantum teleportation experiment with a fiber-delayed Bell State Measurement (BSM) is reported. The source creating the qubits to be teleported and the source creating the necessary entangled state are connected to the beam splitter realizing the BSM by two 2 km long optical fibers. In addition, the teleported qubits are analyzed after 2,2 km of optical fiber, in another lab separated by 55 m. Time bin qubits carried by photons at 1310 nm are teleported onto photons at 1550 nm. The fidelity is of 77%, above the maximal value obtainable without entanglement. This is the first realization of an elementary quantum relay over significant distances, which will allow an increase in the range of quantum communication and quantum key distribution.Comment: 4 pages, submitte

Theoretical X-Ray Absorption Debye-Waller Factors

An approach is presented for theoretical calculations of the Debye-Waller factors in x-ray absorption spectra. These factors are represented in terms of the cumulant expansion up to third order. They account respectively for the net thermal expansion $\sigma^{(1)}(T)$, the mean-square relative displacements $\sigma^2(T)$, and the asymmetry of the pair distribution function $\sigma^{(3)}(T)$. Similarly, we obtain Debye-Waller factors for x-ray and neutron scattering in terms of the mean-square vibrational amplitudes $u^2(T)$. Our method is based on density functional theory calculations of the dynamical matrix, together with an efficient Lanczos algorithm for projected phonon spectra within the quasi-harmonic approximation. Due to anharmonicity in the interatomic forces, the results are highly sensitive to variations in the equilibrium lattice constants, and hence to the choice of exchange-correlation potential. In order to treat this sensitivity, we introduce two prescriptions: one based on the local density approximation, and a second based on a modified generalized gradient approximation. Illustrative results for the leading cumulants are presented for several materials and compared with experiment and with correlated Einstein and Debye models. We also obtain Born-von Karman parameters and corrections due to perpendicular vibrations.Comment: 11 pages, 8 figure