An experimental search for an electric dipole moment (EDM) of the neutron has been carried out at the Institut Laue-Langevin, Grenoble. Spurious signals from magnetic-field fluctuations were reduced to insignificance by the use of a cohabiting atomic-mercury magnetometer. Systematic uncertainties, including geometric-phase-induced false EDMs, have been carefully studied. The results may be interpreted as an upper limit on the neutron EDM of |d(n)|< 2.9 x 10(-26)e cm (90% C.L.).

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 d n ¼ −0.21 AE 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.).

No abstract

We present the result of an experiment to measure the electric dipole moment (EDM) of the neutron at the Paul Scherrer Institute using Ramsey's method of separated oscillating magnetic fields with ultracold neutrons. Our measurement stands in the long history of EDM experiments probing physics violating timereversal invariance. The salient features of this experiment were the use of a 199 Hg comagnetometer and an array of optically pumped cesium vapor magnetometers to cancel and correct for magnetic-field changes. The statistical analysis was performed on blinded datasets by two separate groups, while the estimation of systematic effects profited from an unprecedented knowledge of the magnetic field. The measured value of the neutron EDM is d n ¼ ð0.0 AE 1.1 stat AE 0.2 sys Þ × 10 −26 e:cm.

A combined fit is presented to data onpp annihilation in flight to final states ηπ 0 π 0 , π 0 π 0 , ηη, ηη and π − π + . The emphasis lies in improving an earlier study of ηπ 0 π 0 by fitting data at ninep momenta simultaneously and with parameters consistent with the two-body channels. There is evidence for all of the I = 0, C = +1qq states expected in this mass range. New resonances are reported with masses and widths (M, Γ) as follows: J PC = 4 −+ (2328 ± 38, Γ = 240 ± 90) MeV, 1 ++ (1971 ± 15, 240 ± 45) MeV, 0 −+ (2285 ± 20, 325 ± 30) MeV, and 0 −+ (2010 +35 −60 , 270 ± 60) MeV. Errors on the masses and widths of other resonances are also reduced substantially. All states lie close to parallel straight line trajectories of excitation number v. mass squared.

Article (Published Version) http://sro.sussex.ac.uk Alterev, I, Harris, Philip, Shiers, David and et al, (2009) Neutron to mirror-neutron oscillations in the presence of mirror magnetic fields. Physical Review D, 80 (3). 032003. ISSN 1550-7998 This version is available from Sussex Research Online: http://sro.sussex.ac.uk/16039/ This document is made available in accordance with publisher policies and may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the URL above for details on accessing the published version. Copyright and reuse:Sussex Research Online is a digital repository of the research output of the University.Copyright and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable, the material made available in SRO has been checked for eligibility before being made available.Copies of full text items generally can be reproduced, displayed or performed and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way.Neutron to mirror-neutron oscillations in the presence of mirror magnetic fields We performed ultracold neutron storage measurements to search for additional losses due to neutron (n) to mirror-neutron (n 0 ) oscillations as a function of an applied magnetic field B. In the presence of a mirror magnetic field B 0 , ultracold neutron losses would be maximal for B % B 0 . We did not observe any indication for nn 0 oscillations and placed a lower limit on the oscillation time of nn 0 > 12:0sat 95% C.L. for any B 0 between 0 and 12:5 T.

No abstract

A description is presented of apparatus used to carry out an experimental search for an electric dipole moment of the neutron, at the Institut Laue-Langevin (ILL), Grenoble. The experiment incorporated a cohabiting atomic-mercury magnetometer in order to reduce spurious signals from magnetic field fluctuations. The result has been published in an earlier letter [1]; here, the methods and equipment used are discussed in detail.in detail in the K 0 system [12] and, more recently, in the B system [13,14]; see, for example, [15] and references therein.The origins of CP violation are still unknown. In the kaon system it is dominated by indirect (∆S = 2) contributions due to mixing. It has been observed [16,17] in direct quark interactions (∆S = 1). Contributions from "superweak" ∆S = 2 interactions specific to the kaon systems have been ruled out.Many alternative theories exist (see, for example, contributions in [18]), but the data from the K 0 and b systems alone are insufficient to distinguish between them. These theories also predict non-zero values for the EDM of the neutron, but the predictions differ, one from another, by many orders of magnitude [19]. The major difference between the theories is that in some, and in particular in the standard SU(2) × U(1) model of electroweak interactions, the contributions to the EDM appear only in second order in the weak interaction coupling coefficient, whereas in others the contributions are of first order in the weak interaction. Detection of the latter larger size of EDM would be evidence for new physics beyond the standard model [20]. The small size of the neutron EDM, as indicated by the measured values displayed in Fig. 1 [1, 21-37], has already eliminated many theories, and is pressing heavily upon the expectations from extensions to the Standard Model through to supersymmetric interactions. B. Implications of non-zero EDM measurementsEDMs are being sought in various systems: the free neutron, the mercury atom [38], and the electron (via the thallium atom [39] and, more recently, the YbF [40] and PbO molecules [41]), in addition to a proposal to study deuterium [42]. The fundamental mechanisms underlying sources of EDMs are different in each system, and the arXiv:1305.7336v2 [physics.ins-det]