Year: 2002
Type: article
Abstract: We have searched for neutron-antineutron oscillations using the 5.56 fiducial kiloton-year exposure of the Soudan 2 iron tracking calorimeter. We require candidate $n\mathrm{n\ifmmode \bar{}\else \={}\fi{}}$ occurrences to have $>~4$ prongs (tracks and showers) and to have kinematics compatible with $\mathrm{n\ifmmode \bar{}\else \={}\fi{}}N$ annihilation within a nucleus. We observe five candidate events, with an estimated background from atmospheric neutrino and cosmic ray induced events of $4.5\ifmmode\pm\else\textpm\fi{}1.2$ events. Previous experiments with smaller exposures observed no candidates, with estimated background rates similar to this experiment. We set a lifetime lower limit at 90% C.L. for the $n\mathrm{n\ifmmode \bar{}\else \={}\fi{}}$ oscillation time in iron: ${T}_{A}(\mathrm{Fe})>7.2\ifmmode\times\else\texttimes\fi{}{10}^{31} \mathrm{yr}.$ The corresponding lower limit for oscillation of free neutrons is ${\ensuremath{\tau}}_{n\mathrm{n\ifmmode \bar{}\else \={}\fi{}}}>1.3\ifmmode\times\else\texttimes\fi{}{10}^{8} \mathrm{sec}.$
Authors: J. Chung, W. W. M. Allison, G. J. Alner, D. S. Ayres, W. L. Barrett, P. M. Border, J. H. Cobb, H. Courant, D. M. Demuth, T. H. Fields, H. R. Gallagher, M. C. Goodman, R. Gran, T. Joffe-Minor, T. Kafka, S. M. S. Kasahara, P. J. Litchfield, W. A. Mann, M. L. Marshak, R. H. Milburn, W. H. Miller, L. Mualem, A. Napier, W. P. Oliver, G. F. Pearce, E. A. Peterson, D. A. Petyt, K. Ruddick, M. Sanchez, J. Schneps, A. Sousa, B. Speakman, J. L. Thron, S. P. Wakely, N. West
Language: English
Topic: Neutrino Physics Research
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2161573005