Date Thesis Awarded
Honors Thesis -- Open Access
Bachelors of Science (BS)
Several important lines of evidence point to the existence of dark matter, but it has not yet been experimentally detected. There are several proposed candidates for what dark matter is like, the most popular being weakly interacting massive particles (WIMPs). It has been well-established in the literature that WIMPs would be captured by the Sun after scattering off of atomic nuclei to a velocity lower than the escape velocity. Over time, many WIMPs would be captured and begin to annihilate in the solar core; this would result in the production of kaons that decay at rest into monoenergetic 236 MeV neutrinos. Several studies of detection of these neutrinos at DUNE have been carried out without any successful discoveries. It has been shown that if the WIMP mass is below 4 GeV, then they will scatter back to velocities above the escape velocity and evaporate prior to annihilation; this suppresses the neutrino signal. Since Jupiter has a cooler core, WIMPs with masses in the 1-4 GeV range will not evaporate and can thus annihilate into monoenergetic neutrinos. This makes Jupiter a promising candidate source for the monoenergetic neutrinos one would expect from WIMP annihilations. Additionally, one could move a detector much closer to Jupiter than to the Sun, thereby increasing the total flux of neutrinos received per second, allowing for a deeper probing of the WIMP mass spectrum. In order to make the comparison to the Sun, I assume a simplified model of both the jovian and solar interiors and compute the rates at which WIMPs are captured, evaporate, and annihilate into neutrinos using a custom-written Fortran program. Finally, I calculate the flux of these neutrinos near the surface of Jupiter and find that it is comparable to the flux at DUNE for masses above 4 GeV and substantially greater in the 1-4 GeV range. Of course, detecting these neutrinos would require a neutrino detector near Jupiter. Obviously, it will be many decades before such a detector can be built, but should direct detection experiments find a WIMP with a mass in the 1-4 GeV range, it may be one of the few ways to learn about the annihilation process. A liquid hydrogen time projection chamber might be able to get precise directional information and energy of these neutrinos (and hydrogen is plentiful in the vicinity of Jupiter). I speculate that such a detector could be placed on the far side of one of Jupiter’s tidally locked inner moons; the moon itself would provide substantial background shielding and the surface would allow easier deployment of solar panels for power generation. I provide a quick summary of each of the four moons and evaluate their viability as a detector location based on factors such as their proximity to Jupiter, their surface activity, and their geographic features.
French, George, "Monoenergetic neutrinos from WIMP annihilations in Jupiter" (2023). Undergraduate Honors Theses. William & Mary. Paper 1969.