Additional results from the first dedicated search for neutron mirror neutron oscillations

The existence of a mirror world holding a copy of our ordinary particle spectrum could lead to oscillations between the neutron(n) and its mirror partner(n'). Such oscillations could manifest themselves in storage experiments with ultracold neutrons whose storage lifetime would depend on the applied magnetic field. Here, extended details and measurements from the first dedicated experimental search for nn' oscillations published in[G.Ban,K.Bodek,M.Daum,R.Henneck,S.Heule,M.Kasprzak, N. Khomutov,K.Kirch,S.Kistryn,A.Knecht,P.Knowles,M.Ku´ zniak,T.Lefort,A.Mtchedlishvili,O.Naviliat-Cuncic,C.Plonka,G.Quemener,M.Rebetez,D.Rebreyend,S.Roccia,G.Rogel,M.Tur,A.Weis,J.Zejma,G.Zsigmond, Direct experimental limit on neutron mirror–neutron oscillations, Phys.Rev.Lett. 99 (2007)161603]will be presented, focussing on a possible dependence of the UCN counts on the magnetic field and its direction. However, at present no significant change in the averaged UCN counts with respect to the applied magnetic field has been found.status: publishe

Towards a new measurement of the neutron electric dipole moment

The effort towards a new measurement of the neutron electric dipole moment (nEDM) at the Paul Scherrer Institute’s (PSI) new high intensity source of ultracold neutrons (UCN) is described. The experimental technique relies on Ramsey’s method of separated oscillatory fields, using UCN in vacuum with the apparatus at ambient temperature. In the first phase, R&D towards the upgrade of the RAL/ Sussex/ILL apparatus is being performed at the Institut Laue-Langevin (ILL). In the second phase the apparatus, moved from ILL to PSI, will allow an improvement in experimental sensitivity by a factor of 5. In the third phase, a new spectrometer should gain an other order of magnitude in sensitivity. The improvements will be mainly due to (1) much higher UCN intensity, (2) improved magnetometry and magnetic field control, and (3) a double chamber configuration with opposite electric field directions.status: publishe