2,513 research outputs found
Exotic coloured fermions and lepton number violation at the LHC
Majorana neutrino mass models with a scale of lepton number violation (LNV)
of order TeV potentially lead to signals at the LHC. Here, we consider an
extension of the standard model with a coloured octet fermion and a scalar
leptoquark. This model generates neutrino masses at 2-loop order. We make a
detailed MonteCarlo study of the LNV signal at the LHC in this model, including
a simulation of standard model backgrounds. Our forecast predicts that the LHC
with 300/fb should be able to probe this model up to colour octet fermion
masses in the range of (2.6-2.7) TeV, depending on the lepton flavour of the
final state.Comment: 14 pages, 2 figure
A macro-realism inequality for opto-electro-mechanical systems
We show how to apply the Leggett-Garg inequality to opto-electro-mechanical
systems near their quantum ground state. We find that by using a dichotomic
quantum non-demolition measurement (via, e.g., an additional circuit-QED
measurement device) either on the cavity or on the nanomechanical system
itself, the Leggett-Garg inequality is violated. We argue that only
measurements on the mechanical system itself give a truly unambigous violation
of the Leggett-Garg inequality for the mechanical system. In this case, a
violation of the Leggett-Garg inequality indicates physics beyond that of
"macroscopic realism" is occurring in the mechanical system. Finally, we
discuss the difficulties in using unbound non-dichotomic observables with the
Leggett-Garg inequality.Comment: 9 pages, 2 figures. Added additional figure (2b), and associated
conten
Precision measurements of large scale structure with future type Ia supernova surveys
Type Ia supernovae are currently the best known standard candles at
cosmological distances. In addition to providing a powerful probe of dark
energy they are an ideal source of information about the peculiar velocity
field of the local universe. Even with the very small number of supernovae
presently available it has been possible to measure the dipole and quadrupole
of the local velocity field out to z~0.025. With future continuous all-sky
surveys like the LSST project the luminosity distances of tens of thousands of
nearby supernovae will be measured accurately. This will allow for a
determination of the local velocity structure of the universe as a function of
redshift with unprecedented accuracy, provided the redshifts of the host
galaxies are known. Using catalogues of mock surveys we estimate that future
low redshift supernova surveys will be able to probe sigma-8 to a precision of
roughly 5% at 95% C.L. This is comparable to the precision in future galaxy and
weak lensing surveys and with a relatively modest observational effort it will
provide a crucial cross-check on future measurements of the matter power
spectrum.Comment: 18 pages, 9 figures, submitted to JCA
Development of PARcific Approach: Participatory Action Research Methodology for Collectivist Health Research.
This article explores the evolution of a novel approach designed to advance qualitative methods in cross-cultural health research. This methodology was developed by synthesising several research methods and involved in-depth stakeholder consultation with participants of a Pacific-based nursing and midwifery health leadership program. Many of these participants played a crucial role in creating, exploring and evaluating several research methods and implementing and evaluating this co-designed research methodology. Starting with a Participatory Action Research framework, the research methodology evolved as it was informed by the local Pacific methodologies (in particular Talanoa and Kakala frameworks), where researchers, co-researchers and participants alike, working from within their own collectivist/individualist paradigms, negotiated cultural differences. Finally, a methodological framework of 'best practice' for future health research methods was developed for use with capacity building research. The new methodology could provide a foundation for future co-designed cross-cultural research in collectivist cultures
Precision Pointing of IBEX-Lo Observations
Post-launch boresight of the IBEX-Lo instrument onboard the Interstellar
Boundary Explorer (IBEX) is determined based on IBEX-Lo Star Sensor
observations. Accurate information on the boresight of the neutral gas camera
is essential for precise determination of interstellar gas flow parameters.
Utilizing spin-phase information from the spacecraft attitude control system
(ACS), positions of stars observed by the Star Sensor during two years of IBEX
measurements were analyzed and compared with positions obtained from a star
catalog. No statistically significant differences were observed beyond those
expected from the pre-launch uncertainty in the Star Sensor mounting. Based on
the star observations and their positions in the spacecraft reference system,
pointing of the IBEX satellite spin axis was determined and compared with the
pointing obtained from the ACS. Again, no statistically significant deviations
were observed. We conclude that no systematic correction for boresight geometry
is needed in the analysis of IBEX-Lo observations to determine neutral
interstellar gas flow properties. A stack-up of uncertainties in attitude
knowledge shows that the instantaneous IBEX-Lo pointing is determined to within
\sim 0.1\degr in both spin angle and elevation using either the Star Sensor
or the ACS. Further, the Star Sensor can be used to independently determine the
spacecraft spin axis. Thus, Star Sensor data can be used reliably to correct
the spin phase when the Star Tracker (used by the ACS) is disabled by bright
objects in its field-of-view. The Star Sensor can also determine the spin axis
during most orbits and thus provides redundancy for the Star Tracker.Comment: 22 pages, 18 figure
Planar Superconducting Resonators with Internal Quality Factors above One Million
We describe the fabrication and measurement of microwave coplanar waveguide
resonators with internal quality factors above 10 million at high microwave
powers and over 1 million at low powers, with the best low power results
approaching 2 million, corresponding to ~1 photon in the resonator. These
quality factors are achieved by controllably producing very smooth and clean
interfaces between the resonators' aluminum metallization and the underlying
single crystal sapphire substrate. Additionally, we describe a method for
analyzing the resonator microwave response, with which we can directly
determine the internal quality factor and frequency of a resonator embedded in
an imperfect measurement circuit.Comment: 4 pages, 3 figures, 1 tabl
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