A new upper limit on the electric dipole moment of the neutron

The neutron Electric Dipole Moment experiment at the Paul Scherrer Institute

“…In order to reduce these problems, a new spin analyzing system has been designed using GEANT4-UCN [5] simulations to simultaneously detect the two neutron spin states. Such a technique had originally been pioneered in early EDM experiments at LNPI [6]. …”

Quark mass uncertainties revive Kim–Shifman–Vainshtein–Zakharov axion dark matter

“…Indeed, the experimental fact that there is not a meson with mass < √ 3m π which can be identified as the Nambu-Goldstone (NG) boson of a spontaneously broken U (1) A global symmetry of the strong interaction implies that there is no axial symmetry, and therefore we must take the presence of the θ term seriously [2]. Experiments limit θ < ∼ 10 −10 [3][4] [5], in contrast to naive expectations that θ should be O(1). The mystery deepens when one considers that the physical observable is not θ itself, butθ = θ−arg det M where M is the quark mass matrix.…”

Electric dipole moment of the neutron in gauge theory

“…то дипольный момент есть D^f D (0), (2> и для мюона, электрона, протона, Л-гиперона и нейтрона имеются следую-щие ограничения: Яд < (0,8 ±4,3)-Ю- 19 е-ем 7 , D e < 3-Ю- 24 е-см 8 , D p < 2-Ю- 20 е-см 9 , D A = (-3,0 ± 7,4).Ю-17 е-см 10 , Z) n <6-10" 25 е-см 11 .…”