# LIMIT ON ${{\boldsymbol n}}{{\boldsymbol n}^{\,'}}$ OSCILLATIONS INSPIRE search

Lee and Yang (LEE 1956 ) proposed the existence of mirror world in an attempt to restore global parity symmetry. See BEREZHIANI 2006 for a recent discussion.
VALUE (s) CL% DOCUMENT ID TECN  COMMENT
$\bf{> 414}$ 90
 2008
CNTR UCN, B field on $\&$ off
• • • We do not use the following data for averages, fits, limits, etc. • • •
$> 12$ 95 1
 2009 A
CNTR UCN, scan 0${}\leq{}B{}\leq{}$12.5 $\mu$T
$> 103$ 95
 2007
CNTR UCN, B field on $\&$ off
1  Losses of neutrons due to oscillations to mirror neutrons would be maximal when the magnetic fields ${{\mathit B}}$ and ${{\mathit B}^{\,'}}$ in the two worlds were equal. Hence the scan over ${{\mathit B}}$ by ALTAREV 2009A: the limit applies for any ${{\mathit B}^{\,'}}$ over the given range. At ${{\mathit B}^{\,'}}$ = 0, the limit is 141 s (95$\%$ CL).
References:
 ALTAREV 2009A
PR D80 032003 Neutron to Mirror-Neutron Oscillations in the Presence of Mirror Magnetic Fields
 SEREBROV 2008
PL B663 181 Experimental Search for Neutron$−$Mirror Neutron Oscillations using Storage of Ultracold Neutrons
 BAN 2007
PRL 99 161603 Direct Experimental Limit on Neutron$−$Mirror-Neutron Oscillations
 BEREZHIANI 2006
PRL 96 081801 Neutron$−$Mirror-Neutron Oscillations: How Fast Might They Be?
 LEE 1956
PR 104 254 Question of Parity Conservation in Weak Interactions