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Nuclear Particle Physics
I presently have research interests in all experimental Halls at Jefferson National Labs

Of Particular Interest

I have particular interest in spin degrees of freedom in charged beam nucleon/nucleus interactions to extract new information about quark and gluon interactions. I also have interests in photoproduction hadronic spectroscopy and have a keen interest in the developed signal recognition and extraction algorithms. It seems likely that the next phase of evolution in nuclear physics analysis will entail the use of increasingly sophisticated pattern recognition algorithms used to extract small signals from complex background. Recently, I have worked on U-Spin symmetry tests of the strange sector Electromagnetic Decays with the use of photoproduction data from Hall B. I have a general interest in Spin Structure physics and the instrumentation of solid polarized targets. I have interests in using Artificial Neural Networks in application to detector calibration, reconstruction, and the reduction of dilution in polarized experiments. All applications of Neural Networks and Multivariate Analysis and learning and recursion algorithms have vast implications for hardware and software in nuclear physics. I also have interests in Quantum Groups. The first research project I work on was in DSG Double Special Gravitation in which hopf algebra is used to develop group like structure after a deformation is made to the standard Lorentz group.

Real Media Video

Mystery of Space

The discovery in 1998 that the Universe is actually speeding up its expansion was a total shock to astronomers. It just seems so counter-intuitive, so against common sense. But the evidence has become convincing. The evidence came from studying distant type Ia supernovae. This type of supernova results from a white dwarf star in binary system. Matter transfers from the normal star to the white dwarf until the white dwarf attains a critical mass (the Chandrasekhar limit) and undergoes a thermonuclear explosion. Because all white dwarfs acheive the same mass before exploding, they all achieve the same luminosity and can be used by astronomers as "standard candles." Thus by observing their apparent brightness, astronomers can determine their distance using the 1/r2 law. By knowing the distance to the supernova, we know how long ago it occurred. In addition, the light from the supernova has been red-shifted by the expansion of the unviverse. By measuring this redshift from the spectrum of the supernova, astronomers can determine how much the universe has expanded since the explosion. By studying many supernovae at different distances, astronomers can piece together a history of the expansion of the universe. In the 1990's two teams of astronomers, the Supernova Cosmology Project and the High-Z Supernova Search, were looking for distant type Ia supernovae in order to measure the expansion rate of the universe with time. They expected that the expansion would be slowing, which would be indicated by the supernovae being brighter than their redshifts would indicate. Instead, they found the supernovae to be fainter than expected. Hence, the expansion of the universe was accelerating! In addition, measurements of the cosmic microwave background indicate that the universe has a flat geometry on large scales. Because there is not enough matter in the universe - either ordinary or dark matter - to produce this flatness, the difference must be attributed to a "dark energy". This same dark energy causes the acceleration of the expansion of the universe. In addition, the effect of dark energy seems to vary, with the expansion of the Universe slowing down and speeding up over different times. Astronomers know dark matter is there by its gravitational effect on the matter that we see and there are ideas about the kinds of particles it must be made of. By contrast, dark energy remains a complete mystery. The name "dark energy" refers to the fact that some kind of "stuff" must fill the vast reaches of mostly empty space in the Universe in order to be able to make space accelerate in its expansion. In this sense, it is a "field" just like an electric field or a magnetic field, both of which are produced by electromagnetic energy. But this analogy can only be taken so far because we can readily observe electromagnetic energy via the particle that carries it, the photon. Some astronomers identify dark energy with Einstein's Cosmological Constant. Einstein introduced this constant into his general relativity when he saw that his theory was predicting an expanding universe, which was contrary to the evidence for a static universe that he and other physicists had in the early 20th century. This constant balanced the expansion and made the universe static. With Edwin Hubble's discovery of the expansion of the Universe, Einstein dismissed his constant. It later became identified with what quantum theory calls the energy of the vacuum.



Mystery of Quarks
(Real Media, 9.5 Mb)

Contact

Dustin Keller
dustin@jlab.org
382 McCormick Rd
Charlottesville,  VA 22904
tel 434-924-9955
fax 757-269-7363

 

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