The search for the neutron electric dipole moment at the Paul Scherrer Institute

C.A. Baker , G. Ban (1) , K. Bodek , M. Burghoff , Z. Chowdhuri (2) , M. Daum (2) , M. Fertl (2) , B. Franke (2) , P. Geltenbort (3) , K. Green , M.G.D. van Der Grinten , E. Gutsmiedl , P.G. Harris , R. Henneck (2) , P. Iaydjiev , S.N. Ivanov , N. Khomutov (3) , M. Kasprzak , K. Kirch (2) , S. Kistryn , S. Knappe-Gr̈uneberg , A. Knecht (2) , P. Knowles , A. Kozela , B. Lauss (2) , T. Lefort (1) , Y. Lemière (1) , O. Naviliat-Cuncic (1) , J.M. Pendlebury (3) , E. Pierre (1, 2) , F.M. Piegsa , G. Pignol (4) , G. Quéméner (1) , S. Roccia , P. Schmidt-Wellenburg (2) , D. Shiers , K.F. Smith , A. Schnabel , L. Trahms , A. Weis , J. Zejma , J. Zenner (2) , G. Zsigmond (2)

1 LPCC - Laboratoire de physique corpusculaire de Caen
2 PSI - Paul Scherrer Institute
3 ILL - Institut Laue-Langevin
4 LPSC - Laboratoire de Physique Subatomique et de Cosmologie

The measurement of the neutron electric dipole moment (nEDM) constrains the contribution of CP-violating terms within both the Standard Model and its extensions. The experiment uses ultracold neutrons (UCN) stored in vacuum at room temperature. This technique provided the last (and best) limit by the RAL/Sussex/ILL collaboration in 2006: dn < 2:9 × 10-26 e cm (90% C.L.). We aim to improve the experimental sensitivity by a factor of 5 within 2-3 years, using an upgrade of the same apparatus. We will take advantage of the increased ultracold neutron density at the Paul Scherrer Institute (PSI) and of a new concept including both, external magnetometers and a cohabiting magnetometer. In parallel, a next generation apparatus with two UCN storage chambers and an elaborate magnetic field control is being designed aiming to achieve another order of magnitude increase in sensitivity, allowing us to put a limit as tight as dn < 5 × 10-28 e cm (95% C.L.), if not establishing a finite value.

Mots clés: Neutron electric dipole moment; Magnetometry; Ultracold neutrons

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

C.A. Baker, G. Ban, K. Bodek, M. Burghoff, Z. Chowdhuri, et al.. The search for the neutron electric dipole moment at the Paul Scherrer Institute. 2nd International Workshop on the Physics of fundamental Symmetries and Interactions - PSI2010, 2010, Villigen, Switzerland. pp.159-167, ⟨10.1016/j.phpro.2011.06.032⟩. ⟨in2p3-00642009⟩