5,788 research outputs found
Discovery Potential for New Phenomena
We examine the ability of future facilities to discover and interpret
non-supersymmetric new phenomena. We first explore explicit manifestations of
new physics, including extended gauge sectors, leptoquarks, exotic fermions,
and technicolor models. We then take a more general approach where new physics
only reveals itself through the existence of effective interactions at lower
energy scales. [Summary Report of the New Phenomena Working Group. To appear in
the Proceedings of the 1996 DPF/DPB Summer Study on New Directions for High
Energy Physics - Snowmass96, Snowmass, CO, 25 June - 12 July 1996.]Comment: 18 pages, LaTex2
On the population of remnant FRII radio galaxies and implications for radio source dynamics
The purpose of this work is two-fold: (1) to quantify the occurrence of
ultra-steep spectrum remnant FRII radio galaxies in a 74 MHz flux limited
sample, and (2) perform Monte-Carlo simulations of the population of active and
remnant FRII radio galaxies to confront models of remnant lobe evolution, and
provide guidance for further investigation of remnant radio galaxies. We find
that fewer than 2 of FRII radio galaxies with S Jy are
candidate ultra-steep spectrum remnants, where we define ultra-steep spectrum
as . Our Monte-Carlo simulations
demonstrate that models involving Sedov-like expansion in the remnant phase,
resulting in rapid adiabatic energy losses, are consistent with this upper
limit, and predict the existence of nearly twice as many remnants with normal
(not ultra-steep) spectra in the observed frequency range as there are
ultra-steep spectrum remnants. This model also predicts an ultra-steep remnant
fraction approaching 10 at redshifts . Importantly, this model
implies the lobes remain over-pressured with respect to the ambient medium well
after their active lifetime, in contrast with existing observational evidence
that many FRII radio galaxy lobes reach pressure equilibrium with the external
medium whilst still in the active phase. The predicted age distribution of
remnants is a steeply decreasing function of age. In other words young remnants
are expected to be much more common than old remnants in flux limited samples.
For this reason, incorporating higher frequency data GHz will be of
great benefit to future studies of the remnant population.Comment: 19 pages, 8 figures, 4 table
Properties of the Charmed P-wave Mesons
Two broad charmed mesons, the D_0^* and D_1', have recently been observed. We
examine the quark model predictions for the D_0^* and D_1' properties and
discuss experimental measurements that can shed light on them. We find that
these states are well described as the broad, j=1/2 non-strange charmed P-wave
mesons. Understanding the D_0^* and D_1' states can provide important insights
into the D_{sJ}^*(2317), D_{sJ}(2460) states whose unexpected properties have
led to renewed interest in hadron spectroscopy.Comment: 7 pages. Some additional discussion and reference
Magnetoplasmons in layered graphene structures
We calculate the dispersion equations for magnetoplasmons in a single layer,
a pair of parallel layers, a graphite bilayer and a superlattice of graphene
layers in a perpendicular magnetic field. We demonstrate the feasibility of a
drift-induced instability of magnetoplasmons. The magnetoplasmon instability in
a superlattice is enhanced compared to a single graphene layer. The energies of
the unstable magnetoplasmons could be in the terahertz (THz) part of the
electromagnetic spectrum. The enhanced instability makes superlattice graphene
a potential source of THz radiation.Comment: 5 pages, 4 figure
Development of the health and economic consequences of smoking interactive model
Objective-To describe the health and economic consequences of smoking model, a user friendly, web based tool, designed to estimate the health and economic outcomes associated with smoking and the benefits of smoking cessation. Results-An overview of the development of the model equations and user interface is given, and data from the UK are presented as an example of the model outputs. These results show that a typical smoking cessation strategy costs approximately pound 1200 per life year saved and pound 22 000 per death averted. Conclusions-The model successfully captures the complexity required to model smoking behaviour and associated mortality, morbidity, and health care costs. Furthermore, the interface provides the results in a simple and flexible way so as to be useful to a variety of audiences and to simulate a variety of smoking cessation methods
Nurse telephone triage for same day appointments in general practice: multiple interrupted time series trial of effect on workload and costs
OBJECTIVE: To compare the workloads of general practitioners and nurses and costs of patient care for nurse telephone triage and standard management of requests for same day appointments in routine primary care. DESIGN: Multiple interrupted time series using sequential introduction of experimental triage system in different sites with repeated measures taken one week in every month for 12 months. SETTING: Three primary care sites in York. Participants: 4685 patients: 1233 in standard management, 3452 in the triage system. All patients requesting same day appointments during study weeks were included in the trial. MAIN OUTCOME MEASURES: Type of consultation (telephone, appointment, or visit), time taken for consultation, presenting complaints, use of services during the month after same day contact, and costs of drugs and same day, follow up, and emergency care. RESULTS: The triage system reduced appointments with general practitioner by 29-44%. Compared with standard management, the triage system had a relative risk (95% confidence interval) of 0.85 (0.72 to 1.00) for home visits, 2.41 (2.08 to 2.80) for telephone care, and 3.79 (3.21 to 4.48) for nurse care. Mean overall time in the triage system was 1.70 minutes longer, but mean general practitioner time was reduced by 2.45 minutes. Routine appointments and nursing time increased, as did out of hours and accident and emergency attendance. Costs did not differ significantly between standard management and triage: mean difference ÂŁ1.48 more per patient for triage (95% confidence interval -0.19 to 3.15). CONCLUSIONS: Triage reduced the number of same day appointments with general practitioners but resulted in busier routine surgeries, increased nursing time, and a small but significant increase in out of hours and accident and emergency attendance. Consequently, triage does not reduce overall costs per patient for managing same day appointments
Discovery Potential for New Phenomena
We examine the ability of future facilities to discover and interpret non-supersymmetric new phenomena. We first explore explicit manifestations of new physics, including extended gauge sectors, leptoquarks, exotic fermions, and technicolor models. We then take a more general approach where new physics only reveals itself through the existence of effective interactions at lower energy scales. [Summary Report of the New Phenomena Working Group. To appear in the Proceedings of the 1996 DPF/DPB Summer Study on New Directions for High Energy Physics - Snowmass96, Snowmass, CO, 25 June - 12 July 1996.
Bose-Einstein condensation and Superfluidity of magnetoexcitons in Graphene
We propose experiments to observe Bose-Einstein condensation (BEC) and
superfluidity of quasi-two-dimensional (2D) spatially indirect magnetoexcitons
in bilayer graphene. The magnetic field is assumed strong. The energy
spectrum of collective excitations, the sound spectrum as well as the effective
magnetic mass of magnetoexcitons are presented in the strong magnetic field
regime. The superfluid density and the temperature of the
Kosterlitz-Thouless phase transition are shown to be increasing functions
of the excitonic density but decreasing functions of and the interlayer
separation . Numerical results are presented from these calculations.Comment: 5 pages, 1 figur
The charmonium and bottomonium mass spectroscopy with a simple approximaton of the kinetic term
In this paper we propose a particular description of meson spectroscopy, with
emphasis in heavy bound states like charmonia and bottomonia, after working on
the main aspects of the construction of an effective potential model. We use
the prerogatives from ``soft QCD'' to determine the effective potential terms,
establishing the asymptotic Coulomb term from one gluon exchange approximation.
At the same time, a linear confinement term is introduced in agreement with QCD
and phenomenological prescription. The main aspect of this work is the
simplification in the calculation, consequence of a precise and simplified
description of the kinetic term of the Hamiltonian. With this proposition we
perform the calculations of mass spectroscopy for charmonium and bottomonium
mesons and we discuss the real physical possibilities of developing a
generalized potential model, its possible advantages relative to experimental
parameterization and complexity in numerical calculations
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