The Th nuclear clock: challenges and opportunities

Thursday 15 Jan 2026, 15:30 → 18:30 Europe/Zurich

This DRD5 WP1 online workshop will focus on the theoretical and experimental needs to move forward with the nuclear transition in Thorium as a sensor of beyond the Standard Model (BSM) physics. We would like to highlight the progress and challenges towards a nuclear clock and towards quantifying and enhancing the sensitivity to New Physics. Our goal is to stimulate a fruitful discussion to identify aspects where the experiments will profit from improved theory predictions/modeling and the theory implications will be refined by more precise experimental input.

For more information on DRD5 activities, see https://drd5.web.cern.ch/. This workshop, organized by Dave Hume (NIST) and Elina Fuchs (DESY & Hannover), is part of Work Package 1.

THE MEETING WILL TAKE PLACE ONLINE VIA ZOOM.

15:30 → 16:00 Opening talk: New Physics motivation for the nuclear clock and challenge to determine the K-factor

Speaker: Gilad Perez (Weizmann Institute)

CERN virtual_GiladPerez.pdf

16:00 → 16:20 First laser-excitation of the Th nucleus and further developments of Th spectroscopy at PTB

Speaker: Dr Ekkehard Peik (PTB)

Peik_Thorium PTB DRD5 workshop.pdf

16:20 → 16:40 Frequency reproducibility of solid-state Th-229 nuclear clocks at high precision

Speaker: Jun Ye

16:40 → 17:00 Th spectroscopy in a trapped-ion system, electron bridge technique and dynamical decoupling

Speaker: David Leibrandt (UCLA)

17:00 → 17:20 Nuclear theory for Th and the K-factor calculation

Speaker: Marianna Safronova (University of Delaware)

Kfactor_NuclearTheory_Safronova_2026Thclock.pdf

17:20 → 17:40 Theoretical perspective on Th-229 39+

Speaker: Karol Koziol

KKoziol_229Th39+.pdf

17:40 → 18:00 Implications of the Th lineshape on Ultralight Dark Matter

Speaker: Fiona Kirk (Weizmann Institute of Science)

presentation_DRD5W1workshop.pdf

18:00 → 18:30 Discussion time

Speakers: David Hume (NIST), Elina Fuchs (DESY and Leibniz University Hannover)