Jun 13 – 17, 2022
Berkeley, CA
US/Pacific timezone

Precision spectroscopy studies of radioactive molecules for fundamental physics

Jun 17, 2022, 9:30 AM
Berkeley, CA

Berkeley, CA

Lawrence Berkeley National Laboratory
Oral Oral Presentations NS2022 Plenary


Silviu-Marian Udrescu (Massachusetts Institute of Technology)


Precision molecular experiments provide a unique tool for the measurement of electroweak nuclear properties and searches for physics beyond the Standard Model (SM). Compared to atoms, certain molecules can offer more than eleven orders of magnitude enhanced sensitivity to violations of fundamental symmetries, enabling precision tests of the SM and the possibility to probe energy scales beyond hundreds of TeV. Containing octupole-deformed nuclei, radium monofluoride (RaF) molecules are expected to be highly sensitive to the parity-violating nuclear anapole moment as well as to the parity- and time-reversal violating nuclear Schiff and magnetic quadrupole moments [Phys. Rev. A 82, 052521 (2010); J. Chem. Phys. 152, 044101 (2020)]. In this talk, I will present the latest results obtained from a series of laser spectroscopy experiments performed on short-lived RaF molecules at the ISOLDE facility at CERN. Using a collinear resonant ionization setup, the rotational and hyperfine structure of $^{226}$RaF and $^{225}$RaF were measured with high precision. This allowed us to establish a laser cooling scheme for these molecules, and to extract the value of the nuclear magnetic moment of the $^{225}$Ra nucleus. Our new results exhibit high sensitivity to the distribution of the nuclear magnetization in the $^{225}$Ra nucleus and represent an increase in precision of at least 3 orders of magnitude compared to our previous studies [Nature 581, 396 (2020); Phys. Rev. Lett. 127, 033001 (2021)]. They are the first of their kind performed on radioactive, short-lived molecules, opening the way for future precision studies of electroweak nuclear properties and new physics searches in these systems.

Primary authors

Silviu-Marian Udrescu (Massachusetts Institute of Technology) Shane Wilkins (Massachusetts Institute of Technology) Breier Alex (University of Kassel) Michail Athanasakis-Kaklamanakis (KU Leuven, CERN) Mia Au (CERN) Ivana Belosevic (TRIUMF) Robert Berger (Philipps – Universität Marburg) Bram van den Borne (KU Leuven) Alex Brinson (Massachusetts Institute of Technology ) Katerina Chrysalidis (CERN) Thomas Cocolios (KU Leuven) Anais Dorne (KU Leuven) Kieran Flanagan (7 - Photon Science Institute, The University of Manchester, CERN) Serge Franchoo (Irène Joliot-Curie Lab) Ronald Fernando Garcia Ruiz (Massachusetts Institute of Technology) Konstantin Gaul (Philipps – Universität Marburg) Geldhof Sarina (KU Leuven) Thomas Giesen (University of Kassel) Ruben de Groote (KU Leuven) Timur Isaev (Moscow State University) Agota Koszorús (KU Leuven) Sonja Kujanpaa (University of Jyväskylä) Louis Lalanne (KU Leuven) Gerda Neyens (KU Leuven, CERN) Miranda Nichols (University of Gothenburg) Holly Perrett (The University of Manchester) J. Reilly (The University of Manchester) Sebastian Rothe (CERN) Adam Vernon (Massachusetts Institute of Technology) Julius Wessolek (The University of Manchester) X.F. Yang (Peking University) Carsten Zulch (Philipps – Universität Marburg)

Presentation materials