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LIMIT ON ${{\mathit n}}{{\mathit n}^{\,'}}$ OSCILLATIONS

INSPIRE   PDGID:

S017NOS

Lee and Yang (LEE 1956) proposed the existence of mirror world in an attempt to restore global parity symmetry. A possible candidate for dark matter. Limits depend on assumptions about fields ${{\mathit B}}$ and ${{\mathit B}^{\,'}}$. See the papers for details. See BEREZHIANI 2018 for a recent discussion.

VALUE (s) CL% DOCUMENT ID TECN  COMMENT $\bf{> 448}$ 90 SEREBROV 2009 A CNTR Assumes ${{\mathit B}^{\,'}}$ $<$ 100 nT • • We do not use the following data for averages, fits, limits, etc. • • $>1$ 95 1 BAN 2023 CNTR UCN, scan of ${{\mathit B}}$ field 2 ALMAZAN 2022 CNTR STEREO, hidden neutron search $\vert{}{\mathit m}_{{{\mathit n}}}–{\mathit m}_{{{\mathit n}^{\,'}}}\vert{}{}\geq{}$ 0. $> 9$ 95 3 ABEL 2021 CNTR UCN, scan of ${{\mathit B}}$ field $>17$ 95 4 BEREZHIANI 2018 CNTR UCN, scan of ${{\mathit B}}$ field $> 12$ 95 5 ALTAREV 2009 A CNTR UCN, scan 0${}\leq{}{{\mathit B}}{}\leq{}$12.5 $\mu $T $> 414$ 90 SEREBROV 2008 CNTR UCN, ${{\mathit B}}$ field on $\&$ off $> 103$ 95 BAN 2007 CNTR UCN, ${{\mathit B}}$ field on $\&$ off 1  BAN 2023 determine limits on the oscillation time for the $\vert \delta $m(nn')$\vert $ range of $2 - 59$ peV. The quoted value is ${\mathit \tau}_{\mathrm {nn'}}/\sqrt {cos (\beta ) }$ $>$ 1 sec. for ${{\mathit B}}$ in $30 - 1143$ $\mu $T, for the case $\beta $ = 0. 2  ALMAZAN 2022 reports an experimental constraint on the probability for neutron conversion into a hidden neutron, $\mathit p$ $<$ $3.1 \times 10^{-11}$ at 95$\%$ CL, which may be used to set a limit on the ${{\mathit n}}{{\mathit n}^{\,'}}$ oscillation time. 3  ABEL 2021 determine several limits on the oscillation time as a function of the mirror magnetic field ${{\mathit B}^{\,'}}$, and of the fixed angle, $\beta $, between the applied magnetic field and ${{\mathit B}^{\,'}}$. The latter is assumed to be bound to Earth. Two values are quoted from two analysis methods: (i) ${\mathit \tau}_{\mathrm {nn'}}/\sqrt {cos (\beta ) }$ $>$ 9 sec for ${{\mathit B}^{\,'}}$ in $5 - 25.4$ $\mu $T, and (ii) for any angle $\beta $, ${\mathit \tau}_{\mathrm {nn'}}$ $>$ 6 sec for ${{\mathit B}^{\,'}}$ in $0.4 - 25.7$ $\mu $T. The authors also quote a limit of 352 sec for the case ${{\mathit B}^{\,'}}$ = 0 T. 4  The ${{\mathit B}}$ field was set to (0.09, 0.12, 0.21) G. Limits on oscillation time are valid for any mirror field ${{\mathit B}^{\,'}}$ in ($0.08 - 0.17$) G, and for aligned fields ${{\mathit B}}$ and ${{\mathit B}^{\,'}}$. For larger values of ${{\mathit B}^{\,'}}$, the limits are significantly reduced. 5  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