New Opportunities for Fundamental Physics Research with Radioactive Molecules
Virtual Meeting

June 28 - July 2, 2021


Overview


Scientific Scope of the Meeting

One of the major open questions of modern science is related to the origin of the matter-antimatter asymmetry in the universe. This asymmetry cannot be explained in the Standard Model as it requires additional sources of CP violation. The existence of a non-zero EDM violates both time-reversal (T) and parity (P) invariance, which is equivalent to CP violation due to the CPT invariance of quantum field theories. EDM measurements of both leptons and hadrons can provide direct answers to the origin of the matter-antimatter asymmetry in the universe, and can be used to provide support or disprove different extensions of the Standard Model of particle physics [Saf18,Chu19].

Molecular systems have proven to be exceptional laboratories to perform EDM measurements. Measurements in molecules have provided the most stringent limit to the electron EDM to date [And18], and are constraining the existence of new physics beyond the Standard Model that includes CP violation at the TeV scale. Thus, molecule CP violation searches offer complementary and cost-effective probes to ongoing searches at high-energy colliders.

As the strength of symmetry-violating effects in molecules scales with the atomic number, nuclear spin and nuclear deformation, molecules containing heavy, radioactive nuclei are predicted to provide enhanced sensitivity in these studies [Aue96,Isa10,Fla14,Fla19]. These radioactive molecules can be used not only to enhance the sensitivity to electron EDM searches but could provide unique laboratories to explore known aspects of the fundamental forces of nature via their extreme sensitivity to hadronic CP violation. Combined with molecular enhancements, these radioactive molecules can have sensitivity larger than state-of-the-art experiments by many orders of magnitude. Radioactive molecules can be tailor made to contain radioisotopes with different nuclear spins, allowing a comprehensive study of nuclear-spin-dependent parity violation interactions in addition to offering complementary probes to hadronic EDM searches [Isa16,Alt18]. Moreover, radioactive isotopes offer enhanced sensitivity to symmetry-violating nuclear moments such as the Schiff moment, magnetic quadrupole moment, and anapole moment [Aue96,Gaf13,Fla14,Fla19].

Radioactive molecules therefore offer a new and unique laboratory in fundamental physics research. However, experimental measurements of such radioactive systems are scarce [Gar20], and quantum chemistry calculations often constitute the only source of available information. As radioactive species are produced in low quantities (typically less than nano-grams), their study requires extremely sensitive experimental techniques. Current techniques developed for stable molecules are not directly applicable to radioactive species. The main goal of this meeting will be to combine expertise from different fields of research to establish a future interdisciplinary collaboration that could overcome the technological and theoretical challenges that have complicated the study of radioactive molecules.

In addition, ongoing developments in different radioactive beam facilities such as FRIB (United States), TRIUMF (Canada), and ISOLDE-CERN (Switzerland) will allow extraordinary access to large quantities of radioactive molecules containing isotopes at the extremes of the nuclear chart. Current programs such as the harvesting initiative at FRIB would allow access to large quantities of long-lived isotopes to be used in “table top” experiments. This meeting aims to combine these advances with world-leading expertise in the use of atoms and molecules for fundamental physics research. Recognized experts from different fields will be invited to discuss the current experimental and theoretical progress towards future opportunities in the study of radioactive molecules for fundamental physics research. This is expected to stimulate new collaborations that will take advantage of five major experimental and theoretical developments in both nuclear science and molecular physics:

  1. Recent developments in the production of radioactive molecules
  2. Ultra-sensitive atomic and molecular spectroscopy techniques
  3. Theoretical nuclear physics
  4. Fundamental physics research with molecular systems
  5. Theoretical quantum chemistry

[Alt18] Altunas et al. Phys. Rev. Lett. 120, 142501 (2018).
[And18] Andreev et al. Nature 562, 355 (2018).
[Aue96] N. Auerbach et a. Phys. Rev. Lett.76, 4316 (1996).
[Chu19] Chupp et al. Rev. Mod. Phys. 91, 015001 (2019)
[Fla14] Flambaum et al. Phys. Rev. Lett. 113, 103003 (2014).
[Fla19] V.V. Flambaum et al. Phys. Rev. C 99 035501 (2019).
[Gaf13] L. Gaffney et al. Nature 497, 199 (2013).
[Gar20] Garcia Ruiz et al. Nature 581, 396 (2020).
[Isa10] Isaev et al. Phys. Rev. A 82, 052521 (2010).
[Isa16] Isaev et al. Phys. Rev. Lett. 116, 063006 (2016).
[Saf18] Safronova et al. Rev. Mod. Phys.90, 025008 (2018).