2015: Revised experimental upper limit on the electric dipole moment of the neutron

Phys. Rev. D 92, – (2015)

Pendlebury JM, Afach S, Ayres NJ, Baker CA, Ban G, Bison G, Bodek K, Burghoff M, Geltenbort P, Green K, Griffith WC, van der Grinten M, Grujic ZD, Harris PG, Hélaine V, Iaydjiev P, Ivanov SN, Kasprzak M, Kermaidic Y, Kirch K, Koch HC, Komposch S, Kozela A, Krempel J, Lauss B, Lefort T, Lemière Y, May DJR, Musgrave M, Naviliat-Cuncic O, Piegsa FM, Pignol G, Prashanth PN, Quéméner G, Rawlik M, Rebreyend D, Richardson JD, Ries D, Roccia S, Rozpedzik D, Schnabel A, Schmidt-Wellenburg P, Severijns N, Shiers D, Thorne JA, Weis A, Winston OJ, Wursten E, Zejma J, Zsigmond G, et al.




We present for the first time a detailed and comprehensive analysis of the experimental results that set the current world sensitivity limit on the magnitude of the electric dipole moment (EDM) of the neutron. We have extended and enhanced our earlier analysis to include recent developments in the understanding of the effects of gravity in depolarizing ultracold neutrons; an improved calculation of the spectrum of the neutrons; and conservative estimates of other possible systematic errors, which are also shown to be consistent with more recent measurements undertaken with the apparatus. We obtain a net result of dn=−0.21±1.82×10−26  e cm, which may be interpreted as a slightly revised upper limit on the magnitude of the EDM of 3.0×10−26  e cm (90% C.L.) or 3.6×10−26  e cm (95% C.L.).