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.).

We report the results of a new experimental search for a permanent electric dipole moment of 199 Hg utilizing a stack of four vapor cells. We find d( 199 Hg) = (0.49±1.29stat ±0.76syst)×10 −29 e cm, and interpret this as a new upper bound, |d( 199 Hg)| < 3.1×10 −29 e cm (95% C.L.). This result improves our previous 199 Hg limit by a factor of 7, and can be used to set new constraints on CP violation in physics beyond the standard model. PACS numbers: 11.30.Er,32.10.Dk,32.80.Xx,24.80.+y The existence of a finite permanent electric dipole moment (EDM) of a particle or atom would violate time reversal symmetry (T ), and would also imply violation of the combined charge conjugation and parity symmetry (CP ) through the CP T theorem [1,2,3]. EDMs are suppressed in the standard model of particle physics (SM), lying many orders of magnitude below current experimental sensitivity. However, it is thought that additional sources of CP violation are needed to account for baryogenesis [4,5], and many theories beyond the SM, such as supersymmetry [6,7], naturally predict EDMs within experimental reach.Experimental searches for EDMs have so far yielded null results. The most precise and significant limits have been set on the EDM of the neutron [8], the electron [9], and the 199 Hg atom [10], leading to tight constraints on supersymmetric extensions of the SM [7]. Here we report the first result of a new mercury experiment, |d( 199 Hg)| < 3.1×10−29 e cm (95% C.L.), which improves our previous limit [10] by a factor of 7 and provides a yet more exacting probe of possible new sources of CP violation.199 Hg has a 1 S 0 electronic ground state and nuclear spin 1/2. An EDM of the ground state atom would point along the nuclear spin axis and arise mainly from CP violation in the nucleus. We measure the nuclear Larmor frequency ν given by hν = |2µB ± 2dE|, where µ and d are the 199 Hg magnetic and electric dipole moments, and B and E are the magnitudes of external magnetic and electric fields aligned parallel (+) or antiparallel (−) with each other. The signature for d = 0 is thus a shift in Larmor frequency when E is reversed relative to B.As shown in Fig. 1, our new apparatus uses a stack of four spin-polarized Hg vapor cells in a common B-field. The middle two cells have oppositely directed E-fields, resulting in EDM-sensitive Larmor shifts of opposite sign; the outer two cells, enclosed by the high voltage (HV) electrodes and thus placed at E = 0, are free of EDM effects and serve to cancel B-field gradient noise and provide checks for spurious HV-correlated B-field shifts.The vapor cells are constructed from high purity fused silica and contain isotopically enriched 199 Hg (92 %) at a density of 4 × 10 13 cm −3 , a paraffin wall coating, and 475 Torr of CO buffer gas. CO efficiently quenches excited state 199 Hg and thus reduces degradation of the wall coating [11]. Spin coherence times T 2 are 100 to 200 sec. A conductive SnO coating on the cell end-caps provides electric field plates separated by 11 mm. The average leakage...

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.

We present the first results of a new search for a permanent electric dipole moment of the 199Hg atom using a UV laser. Our measurements give d(199Hg) = -(1.06+/-0.49+/-0.40)x10(-28)e cm. We interpret the result as an upper limit absolute value [d(199Hg)]<2.1x10(-28)e cm (95% C.L.), which sets new constraints on theta bar;(QCD), chromo-EDMs of the quarks, and CP violation in supersymmetric models.

We analyzed organophosphorus pesticide exposure in 218 farm worker households in agricultural communities in Washington State to investigate the take-home pathway of pesticide exposure and to establish baseline exposure levels for a community intervention project. House dust samples (n = 156) were collected from within the homes, and vehicle dust samples (n = 190) were collected from the vehicles used by the farm workers to commute to and from work. Urine samples were obtained from a farm worker (n = 213) and a young child (n = 211) in each household. Dust samples were analyzed for six pesticides, and urine samples were analyzed for five dialkylphosphate (DAP) metabolites. Azinphosmethyl was detected in higher concentrations (p < 0.0001) than the other pesticides: geometric mean concentrations of azinphosmethyl were 0.53 micro g/g in house dust and 0.75 micro g/g in vehicle dust. Dimethyl DAP metabolite concentrations were higher than diethyl DAP metabolite concentrations in both child and adult urine (p < 0.0001). Geometric mean dimethyl DAP concentrations were 0.13 micro mol/L in adult urine and 0.09 micro mol/L in child urine. Creatinine-adjusted geometric mean dimethyl DAP concentrations were 0.09 micro mol/g in adult urine and 0.14 micro mol/g in child urine. Azinphosmethyl concentrations in house dust and vehicle dust from the same household were significantly associated (r2 = 0.41, p < 0.0001). Dimethyl DAP levels in child and adult urine from the same household were also significantly associated (r2 = 0.18, p < 0.0001), and this association remained when the values were creatinine adjusted. The results of this work support the hypothesis that the take-home exposure pathway contributes to residential pesticide contamination in agricultural homes where young children are present.