University of Tennessee-Knoxville
SPS Award for Outstanding Undergraduate Research
Neutron-mirror neutron oscillations in a residual gas environment
Louis Varriano is in his second year in the Physics Department at the University of Tennessee, Knoxville. He currently serves as the President of the Society of Physics Students chapter at UTK and has worked to expand the membership and involvement of the chapter, as well as the number of physics students who actively participate in research. Through his efforts, the Society of Physics Students at UTK has partnered with other on-campus organizations to spearhead a monthly science-outreach program at a local elementary school for children in the community. The chapter also hosts public demonstrations in the downtown district for outreach and donations and has also performed demonstrations on behalf of the university and other charitable groups. Louis also leads a STEM education pilot program for the Boy Scouts of America at an area elementary school, along with several other SPS members. Louis has also worked to increase the amount of funding that his department provides for physics undergraduates and SPS activities. In addition to his interest in physics outreach, Louis works with a faculty member on theoretical dark matter research under a mirror matter hypothesis. He has presented his work on several occasions, including at the meeting of the Southeastern Section of the American Physical Society in 2014. Louis also has a keen interest in science and energy policy and plans to attend graduate school to further this interest.
Both mirror matter, a candidate for dark matter, and ordinary matter can have similar properties and self-interactions but will interact only gravitationally with each other, in accordance with observational evidence of dark matter. Although mirror matter does not couple to ordinary matter by Standard Model interactions, some additional interactions might exist, providing small mixing of ordinary matter neutral states, like the neutron, with mirror components. Three separate experiments have been performed in the last decade to detect the possibility of neutronmirror neutron oscillations. In the analysis of the data of these experiments, the effect of the presence of residual gas (due to an imperfect vacuum) was not considered. This work provides a formalism for understanding the interaction of the residual gas in an experiment with ultracold neutrons. This residual gas effect that was previously considered as negligible has an impact on the probability of neutron to mirror neutron transformation. This formalism is used to evaluate the three previous experiments and provide a small correction to these experiments. The density matrix formalism also provides a framework for the future mirror matter search experiments and can be used to evaluate experiments for effects from the presence of mirror matter and from a mirror magnetic field, which have not been considered before. Furthermore, the formalism is applied to neutron-antineutron oscillations for potential future experiments. This work was conducted in conjunction with Boris Kerbikov (ITEP, Moscow) and Yuri Kamyshkov (University of Tennessee, Knoxville).