Soft x-ray spectroscopy is an experimental technique that provides a unique perspective on many
important material properties. When combined with first principles electronic structure calculations, everything from the bulk band gap, to site-specific charge densities can be determined and understood. This talk will look at the application of these techniques to several technologically important nitrides and oxides, and emphasize how they can provide information on the structure-property relationships that are key to engineering new materials
There is intense activity in the search of glueballs, light hybrids and multiquark states, either as supernumerary states with ordinary quantum numbers JPC, or as genuine exotics with JPC that cannot be matched by ordinary quantum numbers. In particular, evidence has been found for 1-+ states between 1 and 2 GeV by VES at Serpukhov, by E852 at Brookhaven, and by COMPASS at CERN, and the search continues at JLab by GLUEX. The structure of these states are still ambiguous. Four-quark states and hybrid states are the most possible explanations. To study these non-qq resonances beyond the conventional quark model, the Wilson coefficients of dimension-8 condensate contribution to the current-current correlator of 1−+ light hybrid current gq(x)γνiGμν(x)q(x) are calculated. With inclusion of these higher-power corrections and updating the input parameters, the mass of the 1−+ light hybrid meson are re-analyzed from Monte-Carlo based QCD sum rules. In this talk, the basic idea of the quark model and QCD sum rules will be briefly reviewed and then the results of calculation and numerical analysis will be presented.
Abstract: The majority of matter in the universe is nonluminous and of unknown composition. It has been dubbed ‘dark matter’ for these reasons. The dark matter problem is one of the most pressing problems in both particle physics and astrophysics. This talk will provide an overview of the study of dark matter from a particle physics perspective. The evidence for the existence of dark matter will be reviewed, and the motivations for particle models of dark matter will be discussed. The talk will conclude with a description of experimental and observational searches for dark matter, including nuclear recoil searches, cosmic ray signals, and production in particle colliders.
Abstract: Ion heating by friction with neutral particles is known to have a significant impact on the F-region ion temperature in the presence of large electric fields, particularly when the ions become supersonic relative to the neutral background population with which they collide. However, what has not been fully characterized is the impact this heating has on ion temperature anisotropy, as well as the influence of these non-Maxwellian velocity distributions on the shape and interpretation of incoherent radar spectra. To study this, reconstructions of incoherent radar spectra made from Monte-Carlo simulations of velocity distributions are being analyzed along-side radar campaigns capable of giving insight into such things as the collision cross-section of different collisions (such as the resonant charge exchange of O+ ions with O). For this research, an experiment was devised to scrutinize the plasma along the magnetic meridian so as to extract electric field and ion temperature information at altitudes where frictional heating plays an important role. The results of this work indicate that, as expected, the line-of-sight component of the plasma drift extracted from different altitudes is consistent throughout the ionosphere above 150 km. However, owing to competition with processes such as heat exchange with electrons, neutral atmospheric uncertainties, and heat conduction from above, extracting information about the effect of frictional heating is difficult unless the electric field is very strong. Here, the first electric field and ion temperature results from these special magnetic meridian scanning modes will be shown.
Title: Space Weather: Finding Field-Aligned Currents during Substorms
Abstract: Near-Earth space is a region whose dynamics are best described by plasmas and the currents they form. To understand the chain of events that leads to space weather phenomena, the connections of the solar wind to the magnetosphere to the ionosphere by such currents need to be understood. In particular, during substorms currents are formed between the magnetosphere and the ionosphere, and a view of incoming and outgoing currents would illustrate the structure of what is called the substorm current wedge. Two scientific tools are considered to do just that in this presentation: the magnetometers aboard the Iridium satellite constellation in the AMPERE project and the radar network SuperDARN. A comparison between AMPERE and SuperDARN methods will be given, as well as the results for a superposed epoch analysis for AMPERE (SuperDARN results up-and-coming).
Our first speaker for the PEGASUS summer student seminar series is Devon Huyghebaert, whose research utilizes the ICEBEAR radar system. Please join us this Tuesday at 3:00 pm in the lounge for cookies and refreshments beforehand.
Title: The ICEBEAR Radar – Hardware and Capabilities
Abstract: Ionospheric radars will be discussed, with a focus on E-region radars and the new ICEBEAR radar.
The talk will delve into the workings of radar systems and signal processing, culminating with an introduction to the ICEBEAR radar. How are radio waves affected by plasma? What can we learn by probing a plasma hundreds of kilometers away using radio waves? What hardware is required in an advanced digital radio/radar system to transmit and receive radio signals? What does ICEBEAR stand for? These all important questions will be answered at the seminar.
There are a number of useful reference management seminars being offered through the University of Saskatchewan Library; take a look at their offerings for the remainder of the Fall 2015 semester. If you haven’t yet developed a system to manage your references, it’s a good opportunity to investigate different tools to make writing papers and citing references as easy as possible. Some upcoming workshops are listed below.
Nov. 3, 12:00 – 1:00, Murray Library, Rm. 145
Instructor: Carolyn Doi
Zotero is a freely available, open source program which allows you to easily save, organize, and cite all of your references. It is available as an extension in Mozilla Firefox or a standalone program. This session offers attendees an introduction to Zotero and how it may be used for library research.
Comprehensive Lit Review – Part B
Nov. 4, 3:30 – 4:30, Murray Library, Rm. 161
Instructor: Li Zhang
This session will describe the reasons for doing a comprehensive literature review, and will focus on designing a search strategy for databases with subject headings such as Medline, ERIC, and PsycINFO. We will briefly cover saving your search, and writing up your literature review.
Nov. 17, 12:00 – 1:00, Murray Library, Rm. 145
Instructor: Carolyn Doi
Mendeley is a free reference manager and academic social network that can help you organize your research, collaborate with others online, and discover the latest research. Automatically generate bibliographies, collaborate easily with other researchers online, easily import papers from other research software, find relevant papers based on what you’re reading, access your papers from anywhere online, read papers on the go with the iPhone app. This session offers attendees an introduction to Mendeley and how it may be used for library research.