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Nature 581, 32-33 (2020)



  1. Hori, M., Aghai-Khozani, H., Sótér, A., Dax, A. & Barna, D. Nature 581, 37–41 (2020).

    Article  Google Scholar 

  2. Pohl, R. et al. Nature 466, 213–216 (2010).

    Article  PubMed  Google Scholar 

  3. Bezginov, N. et al. Science 365, 1007–1012 (2019).

    Article  PubMed  Google Scholar 

  4. Xiong, W. et al. Nature 575, 147–150 (2019).

    Article  PubMed  Google Scholar 

  5. McGrew, W. F. et al. Nature 564, 87–90 (2018).

    Article  PubMed  Google Scholar 

  6. Ahmadi, M. et al. Nature 557, 71–75 (2018).

    Article  PubMed  Google Scholar 

  7. Lattes, C. M. G., Muirhead, H., Occhialini, G. P. S. & Powell, C. F. Nature 159, 694–697 (1947).

    Article  Google Scholar 

  8. Yukawa, H. Proc. Phys. Math. Soc. Japan 17, 48–57 (1935).

    Google Scholar 

  9. Hori, M. et al. Science 354, 610–614 (2016).

    Article  PubMed  Google Scholar 

Download references


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