- New DIFT Colloquium “Buckets versus pipes: the neutron lifetime puzzle” by Benjamin Grinstein
On Wednesday , May 13, the Institute for Theoretical Physics (IFT) and the Department of Theoretical Physics at the Universidad Autónoma de Madrid (UAM) held a new edition of the DIFT Colloquium, which took place in the CFTMAT Auditorium from 3:30 to 5:00 p.m. The lecture, titled “Buckets versus pipes: the neutron lifetime puzzle”, was delivered by Benjamin Grinstein, a renowned physicist from The University of California, San Diego, USA.
A precise knowledge of the neutron lifetime is important because it serves as a fundamental input for Big Bang Nucleosynthesis (BBN) models, which predict the primordial abundances of light elements. It also enters in the determination of the Cabibbo mixing angle, crucial in testing the validity of the CKM theory of quark flavor, in understanding reactor neutrino detection rates and the behavior of matter in extreme environments like neutron stars. Precise experiments give very precise results, but the values determined differ by over 1% with high statistical significance depending on the technology used for the experiment. In this talk I will review this so-called “neutron lifetime puzzle” and some of the proposed solutions.
This lecture is part of the DIFT Colloquia 2026, organized by the Department of Theoretical Physics at the Universidad Autónoma de Madrid and the Instituto de Física Teórica (IFT UAM-CSIC). Held in Madrid on May 13, 2026.