##### Scientists:

** Tsung-Dao Lee (李政道) and Chen-Ning Yang (杨振宁)** shared the 1957 Nobel Prize on their parity violation work [T. D. Lee and C. N. Yang, Phys. Rev. 104, 254 (1956)], which also opened the door to the studies of mirror symmetry.

**Edward W. Kolb** is a great cosmologist and his early work on mirror matter has fully turned my attention to mirror matter theory. The beautiful picture about mirror-matter in the early Universe is strikingly presented in his Nature paper [E. W. Kolb, D. Seckel, and M. S. Turner, Nature 314, 415 (1985)]; I leaned a lot from his classic textbook “the early universe” with M.S. Turner.

**Zurab Berezhiani** is probably the most active and persistent theorist on studies of mirror matter theory. I have been intrigued by many of his works. In particular, his n-n’ oscillation work [Z. Berezhiani and L. Bento, Phys. Rev. Lett. 96, 081801 (2006)] was the first to point me to the connection between n-n’ oscillations and the neutron lifetime anomaly. And their following work on the same model applied to ultrahigh energy cosmic rays [Z. Berezhiani and L. Bento, Phys. Lett. B 635, 253 (2006)] directly motivated my similar work on cosmic rays, which can provide an estimate on the cosmological parameter T’/T of the new model M^{3} and SM^{3}.

**Steven Weinberg**, who won the 1979 Nobel prize for his contribution to the establishment of the Standard Model, is truly a master in physics. I benefit a lot from many insights related to symmetry breaking, mass relations, renormalization, etc., in his classic textbooks “the quantum theory of fields” and “gravitation and cosmology” where I first learned the thermal history of the early universe [Note: the actual work should be acknowledged and credited to Jim Peebles who won the 2019 Nobel prize]. I also found his paper on the limits of particle spins in quantum field theory is illuminating [Weinberg and Witten, Phys. Lett. B 96, 59 (1980)].

**Yoichiro Nambu (南部陽一郎)** won the 2008 Nobel prize and had many ingenious ideas that have greatly shaped my research. The mechanism on spontaneous symmetry breaking [Y. Nambu and G. Jona-Lasinio, Phys. Rev. 122, 345 (1961)], quasi-Supersymmetry and quark condensation [Y. Nambu, in New Theories in Physics (World Scientific, Singapore, Kazimierz, Poland, 1988) pp. 1-10; in New Trends in Strong Coupling Gauge Theories (World Scientific, Singapore, Nagoya, Japan, 1988) pp. 3-11], are among the most insightful.

**Gerard ‘t Hooft and Frans R. Klinkhamer** on their topological studies of quantum field theory (QFT). The first topological solution in QFT: instanton and U(1) problem [G. ‘t Hooft, Phys. Rev. Lett. 37, 8 (1976); Phys. Rev. D 14, 3432 (1976)]. Sphalerons under different gauge symmetry breakings: electroweak sphaleron [F. R. Klinkhamer and N. S. Manton, Phys. Rev. D 30, 2212 (1984)]; SU(3) sphaleron [F. R. Klinkhamer and P. Nagel, Phys. Rev. D 96, 016006 (2017)].

##### Experiments and Observations:

**W. Mampe, P. Ageron, C. Bates, J. M. Pendlebury, and A. Steyerl, Phys. Rev. Lett. 63, 593, (1989)** : An early “bottle” experiment, although using a material trap, is one of the most beautiful experiments in the history. A very clever way to obtain the true beta decay rate as measured in the “beam” approach. Unfortunately, its unique contribution in neutron lifetime studies has been ignored in the compilation by Particle Data Group.

**Best “beam” neutron lifetime measurements**: J. S. Nico, M. S. Dewey, D. M. Gilliam, F. E. Wietfeldt, X. Fei, W. M. Snow, G. L. Greene, J. Pauwels, R. Eykens, A. Lamberty, J. V. Gestel, and R. D. Scott, Phys. Rev. C 71, 055502 (2005); A. T. Yue, M. S. Dewey, D. M. Gilliam, G. L. Greene, A. B. Laptev, J. S. Nico, W. M. Snow, and F. E. Wietfeldt, Phys. Rev. Lett. 111, 222501 (2013).

**Best “bottle” measurement using a magnetic trap**: R. W. Pattie, N. B. Callahan, C. Cude-Woods, E. R. Adamek, L. J. Broussard, S. M. Clayton, S. A. Currie, E. B. Dees, X. Ding, E. M. Engel, and others, Science 360, 627 (2018). The difference between this measurement and “beam” values gives the so-called neutron lifetime anomaly at 4-sigma level.

**Other magnetic “bottle” measurements**: K. K. H. Leung, P. Geltenbort, S. Ivanov, F. Rosenau, O. Zimmer, Phys. Rev. C 94 (4) (2016) 045502 (2016); V. F. Ezhov, A. Z. Andreev, G. Ban, B. A. Bazarov, P. Geltenbort, A. G. Glushkov, V. A. Knyazkov, N. A. Kovrizhnykh, G. B. Krygin, O. Naviliat-Cuncic, V. L. Ryabov, JETP Lett. 107, 671 (2018); S. N. Dzhosyuk, A. Copete, J. M. Doyle, L. Yang, K. J. Coakley, R. Golub, E. Korobkina, T. Kreft, S. K. Lamoreaux,

A. K. Thompson, G. L. Yang, P. R. Huffman, J. Res. Natl. Inst. Stand. Technol. 110, 339 (2005). Loss of neutrons (most likely due to n-n’ oscillations) were shown.

**Non-measured branching fraction of neutral kaon invisible decays**: S. N. Gninenko, Phys. Rev. D 91, 015004 (2015). Very surprisingly, such an important branching fraction has not been measured so far, even though a large value of ~10^{-4} is predicted in the new model.

**Ultrahigh energy cosmic rays**: Pierre Auger Collaboration, Phys. Rev. Lett. 101 (6) (2008) 061101, Astrophys. J. 862 (2) (2018) 91; High Resolution Fly’s Eye Collaboration, Phys. Rev. Lett. 100 (10) (2008) 101101. The observations can be naturally explained under the new mirror matter theory.

**CKM matrix element measurements**: M. Moulson, arXiv:1704.04104; B. Märkisch, H. Mest, H. Saul, X. Wang, H. Abele, D. Dubbers, M. Klopf, A. Petoukhov, C. Roick, T. Soldner, D. Werder, Phys. Rev. Lett. 122 (24) (2019) 242501. Too many including lattice calculations to list all here.

**Astronomical observations**: S. J. Smartt, Progenitors of Core-Collapse Supernovae, Annu. Rev. Astron. Astrophys. 47, 63 (2009); T. Faran, D. Poznanski, A. V. Filippenko, R. Chornock, R. J. Foley, M. Ganeshalingam, D. C. Leonard, W. Li, M. Modjaz, F. J. D. Serduke, J. M. Silverman, A sample of Type II-L supernovae, Mon. Not. R. Astron. Soc. 445, 554 (2014); T. C. Beers, N. Christlieb, The discovery and analysis of very metalpoor stars in the galaxy, Annu. Rev. Astron. Astrophys. 43, 531 (2005); D. Carollo, K. Freeman, T. C. Beers, V. M. Placco, J. Tumlinson, S. L. Martell, Carbon-enhanced metal-poor stars: CEMP-s and CEMP-no subclasses in the halo system of the milky way, Astrophys. J. 788, 180 (2014). Too many to list all here.

##### Other Key Theoretical Ideas:

**Inflation using mirror matter theory**: H. M. Hodges, Phys. Rev. D 47, 456 (1993). This work demonstrates how a reasonable temperature ratio of T’/T (e.g., 1/3) could be obtained.

**Neutron dark decays**: B. Fornal and B. Grinstein, Phys. Rev. Lett. 120, 191801 (2018). n-n’ oscillations is just a topological manifestation of such decays.

**Strongly self-interacting dark matter**: D. N. Spergel and P. J. Steinhardt, Phys. Rev. Lett. 84, 3760 (2000). This almost screams out for mirror matter.

**Witten-Veneziano relation for \(\eta’\) meson mass**: E. Witten, Nucl. Phys. B 156, 269 (1979); G. Veneziano, Nucl. Phys. B 159, 213 (1979). We need strange quark condensation here.

**Top quark condensation**: W. A. Bardeen, C. T. Hill, and M. Lindner, Phys. Rev. D 41, 1647 (1990). A complete description of top quark condensation based on Nambu’s idea.

**Higgs mechanism and quark condensation**: Tohru Eguchi, New approach to collective phenomena in superconductivity models, Phys. Rev. D 14, 2755-2763 (1976); Anna Hasenfratz, Peter Hasenfratz, Karl Jansen, Julius Kuti, and Yue Shen, The equivalence of the top quark condensate and the elementary Higgs field, Nucl. Phys. B 365, 79-97 (1991).

**“Matter” effect in neutrino oscillations**: C. Giunti, C. W. Kim, Fundamentals of Neutrino Physics and Astrophysics, Oxford University Press, 2007. [original ideas should be credited to L. Wolfenstein, Phys. Rev. D 17, 2369 (1978) and S. P. Mikheev and A. Y. Smirnov, Sov. J. Nucl. Phys. 42, 913 (1985)]. The whole description can be borrowed for the medium effect in n-n’ oscillations.

**CP violation and strong CP problem**: I. I. Bigi and A. I. Sanda, CP Violation, 2nd ed. (Cambridge University Press, 2009).

**Review articles on mirror matter theory**: R. Foot, Int. J. Mod. Phys. D 13, 2161 (2004); Z. Berezhiani, Int. J. Mod. Phys. A 19, 3775 (2004).

**Twin Higgs models**: Z. Chacko, H.-S. Goh, and R. Harnik, Phys. Rev. Lett. 96, 231802 (2006). Stability of Higgs mass is protected by the mirror symmetry.

**Better radiative corrections on Vud**: C.-Y. Seng, M. Gorchtein, H. H. Patel, M. J. Ramsey-Musolf, Phys. Rev. Lett. 121 (24) (2018) 241804. Combined with meson decay data, this indicates that Vud from the nuclear 0+->0+ decays may be overestimated.

**“High- and low-frequency events” and r-process nuclei**: Y. Z. Qian, Prog. Part. Nucl. Phys. 50, 153 (2003). This tells us that supernova explosions can be categorized into two distinct types of events.

**3-alpha process and 12C formation**: F. Hoyle, Astrophys. J. Suppl. Ser.

1, 121 (1954). This also indicates that the proposed 12C(a,g) and fusion reactions are not feasible for the formation of intermediate nuclei up to iron when modern data are considered.

**Nucleosynthesis and evolution of stars**: E. M. Burbidge, G. R. Burbidge, W. A. Fowler, and F. Hoyle, Rev. Mod. Phys. 29, 547 (1957); Bernard E. J. Pagel, nucleosynthesis and chemical evolution of galaxies, Cambridge University Press, 1997; C. E. Rolfs, W. S. Rodney, Cauldrons in the Cosmos: Nuclear Astrophysics, University of Chicago Press, 1988.