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Title: Neutron Electric Dipole Moment

Authors:
ORCiD logo [1]
  1. Los Alamos National Laboratory
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC). High Energy Physics (HEP) (SC-25)
OSTI Identifier:
1378912
Report Number(s):
LA-UR-17-27868
DOE Contract Number:
AC52-06NA25396
Resource Type:
Conference
Resource Relation:
Conference: Lattice QCD ; 2017-08-28 - 2017-08-28 ; Santa Fe, New Mexico, United States
Country of Publication:
United States
Language:
English
Subject:
Atomic and Nuclear Physics

Citation Formats

Bhattacharya, Tanmoy. Neutron Electric Dipole Moment. United States: N. p., 2017. Web.
Bhattacharya, Tanmoy. Neutron Electric Dipole Moment. United States.
Bhattacharya, Tanmoy. 2017. "Neutron Electric Dipole Moment". United States. doi:. https://www.osti.gov/servlets/purl/1378912.
@article{osti_1378912,
title = {Neutron Electric Dipole Moment},
author = {Bhattacharya, Tanmoy},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month = 8
}

Conference:
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  • The use of an ultracold neutron interferometer incorporating an electrostatic accelerator having a strong electric field gradient to accelerate neutrons by their possible electric dipole moment is proposed as a method of measuring the neutron electric dipole moment. The method appears to have the possibility of extending the sensitivity of the measurement by several orders of magnitude, perhaps to 10{sup -30} e-cm. 9 refs., 3 figs.
  • There are many different theories of CP violation, all of which can fit the experimental information available from K decays. There have been many attempts to compute the neutron electric dipole moment in these theories, which have all concentrated on one particular mechanism for the generation of the neutron edm. Here we consider both quark level and hadronic level processors, and argue that there is no double counting in simply adding these terms. We then survey the results obtained in the standard model, in the Weinberg Model and in the Left Right symmetric model. The present upper bound is 2.6more » x 10/sup -25/ e cm, we show that the Weinberg Model would give a dipole moment greater than 1 x 10/sup -25/ e cm, and the L-R symmetric model gives a value in the range 1.9 x 10/sup -26/ e cm to 1.9 x 10/sup -27/ e cm - the range being fixed by the recently observed value of epsilon'/epsilon = (3.3 +- 1.1) x 10/sup -3/. The standard model gives much smaller values - of the order 10/sup -32/ e cm. (AIP)« less
  • We gave an overview of various mechanism for CP violation paying special attention to their prediction of the neutron electric dipole moment. The implication of the recent developments associated with the color electric dipole moment of gluon in various models of CP-violation are then critically assessed. 25 refs.
  • A new experiment has been proposed at Los Alamos National Laboratory to measure the neutron electric dipole moment (EDM) to 4{times}10{sup {minus}28} ecm, a factor of 250 times better than the current experimental limit. Such a measure of the neutron EDM would challenge the theories of supersymmetry and time reversal violation as the origin of the observed cosmological asymmetry in the ratio of baryons to antibaryons. One possible design for this new experiment includes the use of LTC SQUIDs coupled to large ({approximately}100 cm{sup 2}) pick-up coils to measure the precision frequency of the spin-polarized {sup 3}He atoms that actmore » as polarizer, spin analyzer, detector, and magnetometer for the ultra-cold neutrons used in the experiment. The method of directly measuring the {sup 3}He precession signal eliminates the need for very uniform magnetic fields (a major source of systematic error in these types of experiments). It is estimated that a flux of {approximately}2{times}10{sup {minus}16} Tm{sup 2} (0.1 {Phi}{sub 0}) will be coupled into the pick-up coils. To achieve the required signal-to-noise ratio one must have a flux resolution of d{Phi}{sub SQ} = 2{times}10{sup {minus}6}{Phi}{sub 0}/{radical}Hz at 10 Hz. While this is close to the sensitivity available in commercial devices, the effects of coupling to such a large pick-up coil and flux noise from other sources in the experiment still need to be understood. To determine the feasibility of using SQUIDs in such an application the authors designed and built a superconducting test cell, which simulates major features of the proposed EDM experiment, and they developed a two-SQUID readout system that will reduce SQUID noise in the experiment. They present an overview of the EDM experiment with SQUIDs, estimations of required SQUID parameters and experimental considerations. The authors also present the measured performance of a single magnetometer in the test cell as well as the performance of the two SQUID readout technique.« less
  • A new experiment has been proposed at Los Alamos National Laboratory to measure the neutron electric dipole moment (EDM) to 4x10{sup {minus}28} ecm, a factor of 250 times better than the current experimental limit. Such a measure of the neutron EDM would challenge the theories of supersymmetry and time reversal violation as the origin of the observed cosmological asymmetry in the ratio of baryons to antibaryons. One possible design for this new experiment includes the use of LTC SQUIDs coupled to large ({approximately}100 cm{sup 2}) pick-up coils to measure the precession frequency of the spin-polarized {sup 3}He atoms that actmore » as polarizer, spin analyzer, detector, and magnetometer for the ultra-cold neutrons used in the experiment. The method of directly measuring the {sup 3}He precession signal eliminates the need for very uniform magnetic fields (a major source of systematic error in these types of experiments). It is estimated that a flux of {approximately}2x10{sup {minus}16} Tm{sup 2} (0.1 F{sub 0}) will be coupled into the pick-up coils. To achieve the required signal-to-noise ratio one must have a flux resolution of d F{sub SQ}=2x10{sup {minus}6} F{sub 0}/{radical}Hz at 10 Hz. While this is close to the sensitivity available in commercial devices, the effects of coupling to such a large pick-up coil and flux noise from other sources in the experiment still need to be understood. To determine the feasibility of using SQUIDs in such an application we designed and built a superconducting test cell, which simulates major features of the proposed EDM experiment, and we developed a two-SQUID readout system that will reduce SQUID noise in the experiment. We present an overview of the EDM experiment with SQUIDs, estimations of required SQUID parameters and experimental considerations. We also present the measured performance of a single magnetometer in the test cell as well as the performance of the two SQUID readout technique« less