2021 Fiscal Year Research-status Report
Uncovering the Local Dark Matter Density in Axion Dark Matter Scenarios
| Project/Area Number |
21K20366
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| Research Institution | The University of Tokyo |
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Principal Investigator |
Eby Joshua 東京大学, カブリ数物連携宇宙研究機構, 特任研究員 (50902095)
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| Project Period (FY) |
2021-08-30 – 2023-03-31
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| Keywords | Axions / Dark Matter / Local density / Axion stars / Bound axion halos |
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| Outline of Annual Research Achievements |
This research direction has led to several very exciting research works, including some still in progress. One main thrust of research has been to determine whether axions can become trapped to the sun, either through adiabatic contraction or some other process. This work is ongoing, but several promising avenues have been identified and it is likely that this work will be completed in the very near future.
Another goal is to develop new proposals to experimentally uncover the local density of dark matter. To this end, I have proposed a new space-based experimental mission using atomic clock technology, which can potentially be uniquely sensitive to axion-like particles. One especially exciting about this proposal is that atomic clocks in space have been proposed for very different reasons, and we have shown that with relatively minimal modification, these missions can probe unique parameter space for bound solar axion halos with radii smaller than the orbital radius of the Earth.
I have also identified a new source of constraint on axions bound to the sun, namely, the presence of such bound axions would disturb asteroid orbits in a way that is potentially observable. I am now working to determine the resulting constraints using real asteroid data, and it may be competitive with or even surpass previous limits. Finally, I have recently identified a possible method to calculate the fraction of DM axions that could be bound in axion stars, an important factor in my ongoing proposal.
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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
The covid-19 pandemic has led to some disruption with international collaborations over the last several months, leading to somewhat slower progress on the project related to formation of bound axion states in the solar system. This project is primarily conducted with scientists in Israel and Germany, and the inability of the collaboration to meet regularly has decreased the rate of progress. Still, we are advancing the project and will hopefully complete it in the next few months.
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| Strategy for Future Research Activity |
I will visit my colleagues in Germany and Israel over the next few months, in an attempt to finalize this important project together with them, related to bound axion states in the solar system. Furthermore, I will complete the analysis of asteroid constraints on the local dark matter density, and I also hope to estimate the fraction of DM bound in axion stars (both are ongoing, and several recent theoretical insights make these projects much more tractable). With these results in hand, a large range of questions related to the local density of dark matter axions will be answered, in accordance with my original proposal.
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| Causes of Carryover |
The remaining funds have been carried over to assist with expenses related to an international trip, to visit collaborators in Germany and Israel with whom a key project is ongoing. The funds were not used in FY2021 because the trip was postponed, due to the ongoing covid-19 pandemic.
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Research Products
(5 results)
