LIMIT ON ${{\boldsymbol n}}{{\overline{\boldsymbol n}}}$ OSCILLATIONS

Mean Time for ${{\boldsymbol n}}{{\overline{\boldsymbol n}}}$ Transition in Vacuum INSPIRE search

A test of $\Delta $B=2 baryon number nonconservation. MOHAPATRA 1980 and MOHAPATRA 1989 discuss the theoretical motivations for looking for ${{\mathit n}}{{\overline{\mathit n}}}$ oscillations. DOVER 1983 and DOVER 1985 give phenomenological analyses. The best limits come from looking for the decay of neutrons bound in nuclei. However, these analyses require model-dependent corrections for nuclear effects. See KABIR 1983 , DOVER 1989 , ALBERICO 1991 , and GAL 2000 for discussions. Direct searches for ${{\mathit n}}$ $\rightarrow$ ${{\overline{\mathit n}}}$ transitions using reactor neutrons are cleaner but give somewhat poorer limits. We include limits for both free and bound neutrons in the Summary Table. See MOHAPATRA 2009 and PHILLIPS 2016 for recent reviews.

VALUE (s) CL% DOCUMENT ID TECN  COMMENT
$\bf{>2.7 \times 10^{8}}$ 90
ABE
2015C
 CNTR ${{\mathit n}}$ bound in oxygen
$\bf{>8.6 \times 10^{7}}$ 90
BALDO-CEOLIN
1994
CNTR Reactor (free) neutrons
• • • We do not use the following data for averages, fits, limits, etc. • • •
$>1.37 \times 10^{8}$ 90 1
AHARMIM
2017
SNO ${{\mathit n}}$ bound in deuteron
$>1.3 \times 10^{8}$ 90
CHUNG
2002B
 SOU2 ${{\mathit n}}$ bound in iron
$>1 \times 10^{7}$ 90
BALDO-CEOLIN
1990
CNTR See BALDO-CEOLIN 1994
$>1.2 \times 10^{8}$ 90
BERGER
1990
FREJ ${{\mathit n}}$ bound in iron
$>4.9 \times 10^{5}$ 90
BRESSI
1990
CNTR Reactor neutrons
$>4.7 \times 10^{5}$ 90
BRESSI
1989
CNTR See BRESSI 1990
$>1.2 \times 10^{8}$ 90
TAKITA
1986
CNTR ${{\mathit n}}$ bound in oxygen
$>1 \times 10^{6}$ 90
FIDECARO
1985
CNTR Reactor neutrons
$>8.8 \times 10^{7}$ 90
PARK
1985B
 CNTR
$>3 \times 10^{7}$
BATTISTONI
1984
NUSX
$> 0.27 - 1.1 \times 10^{8}$
JONES
1984
CNTR
$>2 \times 10^{7}$
CHERRY
1983
CNTR
1  The AHARMIM 2017 value is an unbounded limit (it does not assume a positive lifetime). The bounded limit is $1.23 \times 10^{8}$ sec.
  References:
AHARMIM 2017
PR D96 092005 Search for Neutron-Antineutron Oscillations at the Sudbury Neutrino Observatory
ABE 2015C
PR D91 072006 The Search for ${{\mathit n}}−{{\overline{\mathit n}}}$ Oscillation in Super-Kamiokande I
CHUNG 2002B
PR D66 032004 Search for Neutron Antineutron Oscillations using Multiprong Events in Soudan-2
BALDO-CEOLIN 1994
ZPHY C63 409 A New Experimental Limit on Neutron Antineutron Oscillations
BALDO-CEOLIN 1990
PL B236 95 A New Experimental Limit on Neutron-Antineutron Transitions
BERGER 1990
PL B240 237 Search for Neutron-Antineutron Oscillations in the FREJUS Detector
BRESSI 1990
NC 103A 731 Final Results of a Search for Free Neutron Anti-Neutron Oscillations
BRESSI 1989
ZPHY C43 175 Search for Free Neutron-Antineutron Oscillations
TAKITA 1986
PR D34 902 Search for Neutron Antineutron Oscillation in ${}^{16}\mathrm {O}$ Nuclei
FIDECARO 1985
PL 156B 122 Experimental Search for Neutron Antineutron Transitions with Free Neutrons
PARK 1985B
NP B252 261 Experimental Limits on Monopole Catalysis, ${{\mathit N}}{{\overline{\mathit N}}}$ Oscillations, and Nucleon Lifetime
BATTISTONI 1984
PL 133B 454 Nucleon Stability, Magnetic Monopoles and Atmospheric Neutrinos in the Mont-Blanc Experiment
JONES 1984
PRL 52 720 Search for ${{\mathit n}}{{\overline{\mathit n}}}$ Oscillation in Oxygen
CHERRY 1983
PRL 50 1354 Experimental Test of Baryon Conservation: a New Limit on Neutron Antineutron Oscillations in Oxygen