848 research outputs found
A strong electroweak phase transition in the 2HDM after LHC8
The nature of the electroweak phase transition in two-Higgs-doublet models is revisited in light of the recent LHC results. A scan over an extensive region of their parameter space is performed, showing that a strongly first-order phase transition favours a light neutral scalar with SM-like properties, together with a heavy pseudo-scalar (m_A^0 > 400 GeV) and a mass hierarchy in the scalar sector, m_H^+ gamma gamma decay channel and find that an enhancement in the branching ratio is allowed, and in some cases even preferred, when a strongly first-order phase transition is required
Acoustic characteristics of externally blown flap systems with mixer nozzles
Noise tests were conducted on a large scale, cold flow model of an engine-under-the-wing externally blown flap lift augmentation system employing a mixer nozzle. The mixer nozzle was used to reduce the flap impingement velocity and, consequently, try to attenuate the additional noise caused by the interaction between the jet exhaust and the wing flap. Results from the mixer nozzle tests are summarized and compared with the results for a conical nozzle. The comparison showed that with the mixer nozzle, less noise was generated when the trailing flap was in a typical landing setting (e.g., 60 deg). However, for a takeoff flap setting (20 deg), there was little or no difference in the acoustic characteristics when either the mixer or conical nozzle was used
Interim prediction method for externally blown flap noise
An interim procedure for predicting externally blown flap (EBF) noise spectra anywhere below a powered lift aircraft is presented. Both engine-under-the-wing and engine-over-the-wing EBF systems are included. The method uses data correlations for the overall sound pressure level based on nozzle exit area and exhaust velocity along with OASPL directivity curves and normalized one-third-octave spectra. Aircraft motion effects are included by taking into account the relative motion of the source with respect to the observer and the relative velocity effects on source strength
Echoes of the electroweak phase transition: discovering a second Higgs doublet through A0 → ZH0
The existence of a second Higgs doublet in nature could lead to a cosmological first-order electroweak
phase transition and explain the origin of the matter-antimatter asymmetry in the Universe. We obtain the
spectrum and properties of the new scalars H0, A0, and H� that signal such a phase transition and show that
the observation of the decay A0 → ZH0 at LHC would be a “smoking gun” signature of these scenarios. We
analyze the LHC search prospects for this decay in the llbb¯ and llWþW− final states, arguing that current
data may be sensitive to this signature in the former channel as well as there being great potential for a
discovery in either channel at the very early stages of the 14 TeV run
Computersimulation zur Verifizierung und Präsentation eines automatisch gesteuerten Mamma-Biopsiesystems
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Die computerunterstützte Simulations- und Animationstechnik ist ein allgemein anerkanntes Hilfsmittel bei der Planung und Realisierung von technischen Systemen. Der Schwerpunkt des Simulations- und Animationseinsatzes lag ursprünglich nur auf der Planungsabsicherung. Zunehmend wird die Simulation und Animation durchgängig in allen Phasen des Planungs- und Realisierungsprozesses genutzt. In einem Forschungsprojekt wurde eine neuartige automatisch gesteuerte Einrichtung zur präzisen Navigation medizinischer Instrumente innerhalb von MRTomographen, insbesondere zur histologischen Sicherung von Kleintumoren, entwickelt. Die gesamte Einrichtung läßt sich gemeinsam mit einem Patienten im Untersuchungsbereich eines MR-Tomographen positionieren. Mittels einer SD-Simulation wie auch Animation konnte eine Überprüfung und Optimierung des komplexen Gesamtsystems, d.h. der einzelnen Systemkomponenten und deren kinematischen Bewegungsabläufe erfolgen. Desweiteren wurde damit eine Grundlage für die Erstellung einer Präsentationsvorlage realisiert, um der Öffentlichkeit die einzelnen Ablaufvorgänge einfach und plausibel darzustellen und zukünftige Anwender in dieses System schnell einzuweisen
Spectroscopic diagnostics of lead stratification in hot subdwarf atmospheres
Heavy metal subdwarfs are a class of hot subdwarfs with very high abundances
of heavy elements, typically around 10 000 times solar. They include stars
which are strongly enhanced in either lead or zirconium, as well as other
elements. Vertical stratification of the enhanced elements, where the element
is concentrated in a thin layer of the atmosphere, has been proposed as a
mechanism to explain the apparent high abundances. This paper explores the
effects of the vertical stratification of lead on theoretical spectra of hot
subdwarfs. The concentration of lead in different regions of the model
atmosphere is found to affect individual lines in a broadly
wavelength-dependent manner, with the potential for lines to display modified
profiles depending on the location of lead enhancement in the atmosphere. This
wavelength dependence highlights the importance of observations in both the
optical and the UV for determining whether stratification is present in real
stars.Comment: 11 pages, 11 figures, accepted for publication in MNRA
Investigating the Portrayal and Influence of Sustainability Claims in an Environmental Advertising Context
The ability of consumer judges to identify sustainable messages in environmental advertising and the effect of these messages is explored. A content analysis provides insight into these judges’ perceptions of the depth of environmental advertising messages. An experiment investigates the influence of sustainable messages and includes collection of cognitive response data to evaluate the cognitive dimension of sustainability messages. Content analysis results suggest that sustainability messages may influence how environmental advertisements are perceived. These findings are supported by the cognitive response data, which shows cognitive differences across advertisements, and the experimental manipulation that suggests sustainable ads may be more involving to consumers
Hierarchical versus degenerate 2HDM: the LHC run 1 legacy at the onset of run 2
Current discussions of the allowed two-Higgs-doublet model parameter space after LHC run 1 and the prospects for run 2 are commonly phrased in the context of a quasidegenerate spectrum for the new scalars. Here, we discuss the generic situation of a two-Higgs-doublet model with a nondegenerate spectrum for the new scalars. This is highly motivated from a cosmological perspective since it naturally leads to a strongly first-order electroweak phase transition that could explain the matter-antimatter asymmetry in the Universe. While constraints from measurements of Higgs signal strengths do not change, those from searches of new scalar states get modified dramatically once a nondegenerate spectrum is considered
Telecommunications systems design techniques handbook
Handbook presents design and analysis of tracking, telemetry, and command functions utilized in these systems with particular emphasis on deep-space telecommunications. Antenna requirements are also discussed. Handbook provides number of tables outlining various performance criteria. Block diagrams and performance charts are also presented
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