Limits on lifetimes for $\mathit bound$ neutrons are given in the section``p PARTIAL MEAN LIVES.”

We average eight of the best nine measurements, those made with ultracold neutrons (UCN's). If we include the one in-beam measurement with a comparable error (YUE 2013), we get $878.6$ $\pm0.6$ s, where the scale factor is now 2.2.

For a recent discussion of the long-standing disagreement between in-beam and UCN results, see CZARNECKI 2018 (Physical Review Letters 120 202002 (2018)). For a full review of all matters concerning the neutron lifetime until about 2010, see WIETFELDT 2011, F.E. Wietfeldt and G.L. Greene, “The neutron lifetime,” Reviews of Modern Physics 83 1173 (2011).

VALUE (s) DOCUMENT ID TECN  COMMENT $\bf{ 878.4 \pm0.5}$ OUR AVERAGE  Error includes scale factor of 1.8.  See the ideogram below. $877.75$ $\pm0.28$ ${}^{+0.22}_{-0.16}$ GONZALEZ 2021 CNTR UCN asym. magnetic trap $878.3$ $\pm1.6$ $\pm1.0$ EZHOV 2018 CNTR UCN magneto-gravit. trap $877.7$ $\pm0.7$ ${}^{+0.4}_{-0.2}$ 1 PATTIE 2018 CNTR UCN asym. magnetic trap $881.5$ $\pm0.7$ $\pm0.6$ SEREBROV 2018 CNTR UCN gravitational trap $880.2$ $\pm1.2$ 2 ARZUMANOV 2015 CNTR UCN double bottle $882.5$ $\pm1.4$ $\pm1.5$ 3 STEYERL 2012 CNTR UCN material bottle $880.7$ $\pm1.3$ $\pm1.2$ PICHLMAIER 2010 CNTR UCN material bottle $878.5$ $\pm0.7$ $\pm0.3$ SEREBROV 2005 CNTR UCN gravitational trap • • We do not use the following data for averages, fits, limits, etc. • • $887$ $\pm14$ ${}^{+7}_{-3}$ 4 WILSON 2021 CNTR space-based ${{\mathit n}}$ rate $887.7$ $\pm1.2$ $\pm1.9$ 5 YUE 2013 CNTR In-beam ${{\mathit n}}$, trapped ${{\mathit p}}$ $881.6$ $\pm0.8$ $\pm1.9$ 6 ARZUMANOV 2012 CNTR See ARZUMANOV 2015 $886.3$ $\pm1.2$ $\pm3.2$ NICO 2005 CNTR See YUE 2013 $886.8$ $\pm1.2$ $\pm3.2$ DEWEY 2003 CNTR See NICO 2005 $885.4$ $\pm0.9$ $\pm0.4$ ARZUMANOV 2000 CNTR See ARZUMANOV 2012 $889.2$ $\pm3.0$ $\pm3.8$ BYRNE 1996 CNTR Penning trap $882.6$ $\pm2.7$ 7 MAMPE 1993 CNTR UCN material bottle $888.4$ $\pm3.1$ $\pm1.1$ 8 NESVIZHEVSKII 1992 CNTR UCN material bottle $888.4$ $\pm2.9$ ALFIMENKOV 1990 CNTR See NESVIZHEVSKII 1992 $893.6$ $\pm3.8$ $\pm3.7$ BYRNE 1990 CNTR See BYRNE 1996 $878$ $\pm27$ $\pm14$ KOSSAKOWSKI 1989 TPC Pulsed beam $887.6$ $\pm3.0$ MAMPE 1989 CNTR See STEYERL 2012 $877$ $\pm10$ PAUL 1989 CNTR Magnetic storage ring $876$ $\pm10$ $\pm19$ LAST 1988 SPEC Pulsed beam $891$ $\pm9$ SPIVAK 1988 CNTR Beam $903$ $\pm13$ KOSVINTSEV 1986 CNTR UCN material bottle $937$ $\pm18$ 9 BYRNE 1980 CNTR $875$ $\pm95$ KOSVINTSEV 1980 CNTR $881$ $\pm8$ BONDARENKO 1978 CNTR See SPIVAK 1988 $918$ $\pm14$ CHRISTENSEN 1972 CNTR 1  PATTIE 2018 uses a new technique, with a semi-toroidal magneto-gravitational asymmetric trap and a novel in situ ${{\mathit n}}$-detector. 2  ARZUMANOV 2015 is a reanalysis of their $2008 - 2010$ dataset, with improved systematic corrections of of ARZUMANOV 2000 and ARZUMANOV 2012. 3  STEYERL 2012 is a detailed reanalysis of neutron storage loss corrections to the raw data of MAMPE 1989, and it replaces that value. 4  WILSON 2021 extract the value from the flux of ${{\mathit n}}$ escaping the moon using data from the Lunar Prospector Neutron Spectrometer. 5  YUE 2013 differs from NICO 2005 in that a different and better method was used to measure the neutron density in the fiducial volume. This shifted the lifetime by +1.4 seconds and reduced the previously largest source of systematic uncertainty by a factor of five. 6  ARZUMANOV 2012 reanalyzes its systematic corrections in ARZUMANOV 2000 and obtains this corrected value. 7  IGNATOVICH 1995 calls into question some of the corrections and averaging procedures used by MAMPE 1993. The response, BONDARENKO 1996, denies the validity of the criticisms. 8  The NESVIZHEVSKII 1992 measurement has been withdrawn by A. Serebrov. 9  The BYRNE 1980 measurement has been withdrawn (J.$~$Byrne, private communication, 1990).

neutron mean life (s)

References