Discovery of Two New Class II Methanol Maser Transitions in G345.01+1.79

We have used the Swedish ESO Submillimetre Telescope (SEST) to search for new class II methanol maser transitions towards the southern source G345.01+1.79. Over a period of 5 days we observed 11 known or predicted class II methanol maser transitions. Emission with the narrow line width and characteristic velocity of class II methanol masers (in this source) was detected in 8 of these transitions, two of which have not previously been reported as masers. The new class II methanol maser transitions are the 13(-3)-12(-4)E transition at 104.1 GHz and the 5(1)-4(2)E transition at 216.9 GHz. Both of these are from transition series for which there are no previous known class II methanol maser transitions. This takes the total number of known class II methanol maser series to 10, and the total number of transitions (or transition groups) to 18. The observed 104.1 GHz maser suggests the presence of two or more regions of masing gas with similar line of sight velocities, but quite different physical conditions. Although these newly discovered transitions are likely to be relatively rare, where they are observed combined studies using the Australia Telescope Compact Array and the Atacama Large Millimeter Array offer the prospect to be able to undertake multi-transition methanol maser studies with unprecedented detail.Comment: 8 pages, 3 figures, accepted for publication in ApJ Letter

Discovery and Identification of W' Bosons at e+e- Colliders

We report on studies of the sensitivity to extra gauge bosons of the reactions e^+ e^- -> nu nubar gamma and e gamma -> nu q + X to extract discovery limits for W' 's. The discovery potential for a W' is, for some models, comparable to that of the LHC. These processes may be also useful for determining W' and Z' couplings to fermions which would complement measurements made at the Large Hadron Collider.Comment: 3 pages, 2 postscript figures, Presented at the DPF2000 Conference, August 9-12, 2000, The Ohio State University, Columbus, Ohi

Properties of the Strange Axial Mesons in the Relativized Quark Model

We studied properties of the strange axial mesons in the relativized quark model. We calculated the $K_1$ decay constant in the quark model and showed how it can be used to extract the $K_1 (^3P_1) - K_1 (^1P_1)$ mixing angle ($\theta_K$) from the weak decay $\tau \to K_1 \nu_\tau$. The ratio $BR(\tau \to \nu_\tau K_1 (1270))/BR(\tau\to \nu_\tau K_1(1400))$ is the most sensitive measurement and also the most reliable since the largest of the theoretical uncertainties factor out. However the current bounds extracted from the TPC/Two-Gamma collaboration measurements are rather weak: we typically obtain $-30^o \lesssim \theta_K \lesssim 50^o$ at 68\% C.L. We also calculated the strong OZI-allowed decays in the pseudoscalar emission model and the flux-tube breaking model and extracted a $^3P_1 - ^1P_1$ mixing angle of $\theta_K \simeq 45^o$. Our analysis also indicates that the heavy quark limit does not give a good description of the strange mesons.Comment: Revised version to be published in Phys. Rev. D. Minor changes. Latex file uses revtex version 3 and epsfig, 4 postcript figures are attached. The full postcript version with embedded figures is available at ftp://ftp.physics.carleton.ca/pub/theory/godfrey/ocipc9512.ps.

Prospects for detection of Υ(1D)→Υ(1S)ππ\Upsilon(1D) \to \Upsilon(1S) \pi \pi via Υ(3S)→Υ(1D)+X\Upsilon(3S) \to \Upsilon(1D) + X

At least one state in the first family of D-wave $b \bar b$ quarkonium levels has been discovered near the predicted mass of 10.16 GeV/$c^2$. This state is probably the one with J=2. This state and the ones with J=1 and J=3 may contribute a detectable amount to the decay $\Upsilon(1D) \to \Upsilon(1S) \pi \pi$, depending on the partial widths for these decays for which predictions vary considerably. The prospects for detection of the chain $\Upsilon(3S) \to \Upsilon(1D) + X \to \Upsilon \pi \pi + X$ are discussed.Comment: 4 pages, LaTeX, 1 figure, to be published in Phys. Rev. D, comment added after Eq. (2

Systems thinking, systems design and learning power in engineering education

Educating Engineers in systems thinking and systems design require an approach to teaching and learning in which the purpose is to achieve competence rather than to acquire specialised subject knowledge, abstracted from its socio-technical context. Such an approach is structured by context-driven enquiry, supported by learning power, positioned at the interface of knowledge generation and use, and grounded in a commitment to sustainable development. Rather than beginning with pre-defined abstract subject knowledge, the students begin with an engineering problem in a particular territory or a place, and develop a systems architecture, a holistic way of defining that territory, which facilitates synergy as well as analysing performance. In order to do this, students need to be able to uncover the different knowledge systems through which their territory can be perceived and known, and explore the different parameters and measurements which can be applied to them. Such 'systems architecting' cannot be achieved through rote learning or the cognitive application of pre-defined knowledge, since by definition the solution to the problem to be solved cannot be known in advance. Rather it depends on the ability to learn, and to progress through an open-ended, formative, dynamic learning process. It is framed by a selected purpose, fuelled by learning power (including creativity, meaning making, curiosity and resilience) and cogenerated through knowledge structuring processes. It begins with experience and observation and concludes with a product which is a unique application of knowledge for a particular engineering purpose. One of the challenges of technology enhanced learning is how to integrate learning design in an architectural framework which leverages mobile, social and 'big' data to enhance the processes and social relationships of learning, rather than simply providing information or evaluating outcomes. The approach presented in this paper outlines what can be understood as 'learning design principles' which support the development of semantic web applications, through the application of learning power and knowledge structuring processes. A pilot study demonstrates that students who successfully undertook an assignment requiring the development of a systems architecture increased in the strategic awareness-a key dimension of learning power. This small pilot study makes a contribution to the debate about the education of Chartered Engineers characterised "by their ability to develop appropriate solutions to engineering problems, using new or existing technologies, through innovation, creativity and change" (UK Engineering Council)

Spin and model identification of Z' bosons at the LHC

Heavy resonances appearing in the clean Drell-Yan channel may be the first new physics to be observed at the proton-proton CERN LHC. If a new resonance is discovered at the LHC as a peak in the dilepton invariant mass distribution, the characterization of its spin and couplings will proceed via measuring production rates and angular distributions of the decay products. We discuss the discrimination of the spin-1 of Z' representative models (Z'_{SSM}, Z'_{psi}, Z'_{eta}, Z'_{chi}, Z'_{LR}, and Z'_{ALR}) against the Randall-Sundrum graviton resonance (spin-2) and a spin-0 resonance (sneutrino) with the same mass and producing the same number of events under the observed peak. To assess the range of the Z' mass where the spin determination can be performed to a given confidence level, we focus on the angular distributions of the Drell-Yan leptons, in particular we use as a basic observable an angular-integrated center-edge asymmetry, A_{CE}. The spin of a heavy Z' gauge boson can be established with A_{CE} up to M_{Z'} \simeq 3.0 TeV, for an integrated luminosity of 100 fb^{-1}, or minimal number of events around 110. We also examine the distinguishability of the considered Z' models from one another, once the spin-1 has been established, using the total dilepton production cross section. With some assumption, one might be able to distinguish among these Z' models at 95% C.L. up to M_{Z'} \simeq 2.1 TeV.Comment: 18 pages, 6 figure

Historical Criminology and the Explanatory Power of the Past

To what extent can the past ‘explain’ the present? This deceptively simple question lies at the heart of historical criminology (research which incorporates historical primary sources while addressing present-day debates and practices in the criminal justice field). This article seeks first to categorise the ways in which criminologists have used historical data thus far, arguing that it is most commonly deployed to ‘problematize’ the contemporary rather than to ‘explain’ it. The article then interrogates the reticence of criminologists to attribute explicative power in relation to the present to historical data. Finally, it proposes the adoption of long time-frame historical research methods, outlining three advantages which would accrue from this: the identification and analysis of historical continuities; a more nuanced, shared understanding of micro/macro change over time in relation to criminal justice; and a method for identifying and analysing instances of historical recurrence, particularly in perceptions and discourses around crime and justice

Multi-transition study and new detections of class II methanol masers

We have used the ATNF Mopra antenna and the SEST antenna to search in the directions of several class II methanol maser sources for emission from six methanol transitions in the frequency range 85-115 GHz. The transitions were selected from excitation studies as potential maser candidates. Methanol emission at one or more frequencies was detected from five of the maser sources, as well as from Orion KL. Although the lines are weak, we find evidence of maser origin for three new lines in G345.01+1.79, and possibly one new line in G9.62+0.20. The observations, together with published maser observations at other frequencies, are compared with methanol maser modelling for G345.01+1.79 and NGC6334F. We find that the majority of observations in both sources are consistent with a warm dust (175 K) pumping model at hydrogen density ~10^6 cm^-3 and methanol column density ~5 x 10^17 cm^-2. The substantial differences between the maser spectra in the two sources can be attributed to the geometry of the maser region.Comment: 13 pages, 6 figures, Accepted for publication in MNRA

A Deep \u3cem\u3eChandra\u3c/em\u3e ACIS Survey of M83

We have obtained a series of deep X-ray images of the nearby galaxy M83 using Chandra, with a total exposure of 729 ks. Combining the new data with earlier archival observations totaling 61 ks, we find 378 point sources within the D25 contour of the galaxy. We find 80 more sources, mostly background active galactic nuclei (AGNs), outside of the D25 contour. Of the X-ray sources, 47 have been detected in a new radio survey of M83 obtained using the Australia Telescope Compact Array. Of the X-ray sources, at least 87 seem likely to be supernova remnants (SNRs), based on a combination of their properties in X-rays and at other wavelengths. We attempt to classify the point source population of M83 through a combination of spectral and temporal analysis. As part of this effort, we carry out an initial spectral analysis of the 29 brightest X-ray sources. The soft X-ray sources in the disk, many of which are SNRs, are associated with the spiral arms, while the harder X-ray sources, mostly X-ray binaries (XRBs), do not appear to be. After eliminating AGNs, foreground stars, and identified SNRs from the sample, we construct the cumulative luminosity function (CLF) of XRBs brighter than 8 × 1035 erg s–1. Despite M83\u27s relatively high star formation rate, the CLF indicates that most of the XRBs in the disk are low mass XRBs