Experimental Search for Neutron to Mirror Neutron Oscillations as an Explanation of the Neutron Lifetime Anomaly
L. J. Broussard, J. Barrow, Lisa DeBeer‐Schmitt, Taylor Dennis, M. R. Fitzsimmons, Matthew Frost, C. E. Gilbert, Francisco M. González, L. Heilbronn, Erik B. Iverson, A.H. Johnston, Y. Kamyshkov, Michelle A. Kline, P. Lewiz, C. Matteson, James Ternullo, L. Varriano, Shaun Vavra
Abstract
An unexplained >4σ discrepancy persists between "beam" and "bottle" measurements of the neutron lifetime. A new model proposed that conversions of neutrons n into mirror neutrons n^{'}, part of a dark mirror sector, can increase the apparent neutron lifetime by 1% via a small mass splitting Δm between n and n^{'} inside the 4.6 T magnetic field of the National Institute of Standards and Technology Beam Lifetime experiment. A search for neutron conversions in a 6.6 T magnetic field was performed at the Spallation Neutron Source which excludes this explanation for the neutron lifetime discrepancy.