Prospects for measuring the electric dipole moment of the electron using electrically trapped polar molecules

Heavy polar molecules can be used to measure the electric dipole moment of the electron, which is a sensitive probe of physics beyond the Standard Model. The value is determined by measuring the precession of the molecule's spin in a plane perpendicular to an applied electric field. The longer this precession evolves coherently, the higher the precision of the measurement. For molecules in a trap, this coherence time could be very long indeed. We evaluate the sensitivity of an experiment where neutral molecules are trapped electrically, and compare this to an equivalent measurement in a molecular beam. We consider the use of a Stark decelerator to load the trap from a supersonic source, and calculate the deceleration efficiency for YbF molecules in both strong-field seeking and weak-field seeking states. With a 1s holding time in the trap, the statistical sensitivity could be ten times higher than it is in the beam experiment, and this could improve by a further factor of five if the trap can be loaded from a source of larger emittance. We study some effects due to field inhomogeneity in the trap and find that rotation of the electric field direction, leading to an inhomogeneous geometric phase shift, is the primary obstacle to a sensitive trap-based measurement.Comment: 22 pages, 7 figures, prepared for Faraday Discussion 14

Pulsed beams as field probes for precision measurement

We describe a technique for mapping the spatial variation of static electric, static magnetic, and rf magnetic fields using a pulsed atomic or molecular beam. The method is demonstrated using a beam designed to measure the electric dipole moment of the electron. We present maps of the interaction region, showing sensitivity to (i) electric field variation of 1.5 V/cm at 3.3 kV/cm with a spatial resolution of 15 mm; (ii) magnetic field variation of 5 nT with 25 mm resolution; (iii) radio-frequency magnetic field amplitude with 15 mm resolution. This new diagnostic technique is very powerful in the context of high-precision atomic and molecular physics experiments, where pulsed beams have not hitherto found widespread application.Comment: 6 pages, 12 figures. Figures heavily compressed to comply with arxiv's antediluvian file-size polic

Population-based patient care study for breast cancer

Background: Different approaches for an effective quality management are funded by the Ministry of Health to verify, to assess and, if necessary to optimize the quality of health care using the tracer diagnoses of breast, rectal, and lung cancer in eight regions in Germany. The conception of these observational studies and initial findings are shown here, using breast cancer in the region of Munich (population 2.4 million) as an example. Patients and Methods: The study started on April 1, 1996. The recruitment phase for all primary boast cancer patients in this region is planned for 2 years with a 3-5-year follow-up. Established documentation sheets are used to document basic medical information of each patient, along with the original reports (pathology: radiotherapy, doctors' reports, etc.), follow-up reports and quality of life questionnaires (QLQ, including the EORTC QLQ C30). Results: In 1996, the Munich region has a crude incidence of 125/100,000 women (world standard 71.5). After almost complete documentation the incidence is 10-15% higher. In the period from April 1 1996 to June 30, 1997 1,360 patients have been recruited into the study. 79% of the patients were 50 years of age or older. pT stages are distributed as follows: pTIS 5%, pT1 54%, pT2 32%, pT3 4%, pT4 6%. 4.5% had primary metastases. Breast-conserving therapy (BCT) was performed in 57% of patients. Five of the 46 departments involved recruited more than 50 patients each within these 14 months. These larger departments treat 59% of all patients. The proportion of older patients and pT4 stages is significantly higher in the smaller departments. BCT is performed significantly more often in the larger departments. First results of quality of life show dependencies on age, but no differences between mastectomy and BCT 3 months after operation. Not only the addressed patients (response rate to QLQ over 80%) but also almost all hospitals and many physicians are milling to support and to partake in quality assurance. 35 hospitals, 46 surgical departments. 80 heads of department and surgically: active general practioners, 330 general practioners. 7 radiotherapy departments, and 13 pathology departments have so far documented for this study. Conclusions: An effective quality management in oncology needs a modern cancer registry which uses documentation sheets as well as original reports and organizes the complicated infrastructure for an interdisciplinary cooperation. To be able to evaluate the health care reality it is necessary to carry out a data analysis and assess each individual case. A feedback of the results have to be available for each physician and each department. The cost of this information management is approximately 0.3% of the health care cost for this group of patients

A robust floating nanoammeter

A circuit capable of measuring nanoampere currents while floating at voltages up to at least 25kV is described. The circuit relays its output to ground potential via an optical fiber. We particularly emphasize the design and construction techniques which allow robust operation in the presence of high voltage spikes and discharges.Comment: 5 pages, 2 figure

Probing the electron EDM with cold molecules

We present progress towards a new measurement of the electron electric dipole moment using a cold supersonic beam of YbF molecules. Data are currently being taken with a sensitivity of $10^{-27}\textrm{e.cm}/\sqrt{\textrm{day}}$. We therefore expect to make an improvement over the Tl experiment of Commins' group, which currently gives the most precise result. We discuss the systematic and statistical errors and comment on the future prospect of making a measurement at the level of $10^{-29}\textrm{e.cm}/\sqrt{\textrm{day}}$.Comment: 8 pages, 6 figures, proceedings of ICAP 200

Prospects for the measurement of the electron electric dipole moment using YbF

We discuss an experiment underway at Imperial College London to measure the permanent electric dipole moment (EDM) of the electron using a molecular beam of YbF. We describe the measurement method, which uses a combination of laser and radiofrequency resonance techniques to detect the spin precession of the YbF molecule in a strong electric field. We pay particular attention to the analysis scheme and explore some of the possible systematic effects which might mimic the EDM signal. Finally, we describe technical improvements which should increase the sensitivity by more than an order of magnitude over the current experimental limit.Comment: 6 pages, 2 figure