Abstract
We report the first observation of the parity-violating gamma-ray asymmetry Aγnp in neutron-proton capture using polarized cold neutrons incident on a liquid parahydrogen target at the Spallation Neutron Source at Oak Ridge National Laboratory. Aγnp isolates the ΔI=1, S31→P31 component of the weak nucleon-nucleon interaction, which is dominated by pion exchange and can be directly related to a single coupling constant in either the DDH meson exchange model or pionless effective field theory. We measured Aγnp=[-3.0±1.4(stat)±0.2(syst)]×10-8, which implies a DDH weak πNN coupling of hπ1=[2.6±1.2(stat)±0.2(syst)]×10-7 and a pionless EFT constant of CS31→P31/C0=[-7.4±3.5(stat)±0.5(syst)]×10-11 MeV-1. We describe the experiment, data analysis, systematic uncertainties, and implications of the result.
| Original language | English |
|---|---|
| Article number | 242002 |
| Journal | Physical Review Letters |
| Volume | 121 |
| Issue number | 24 |
| DOIs | |
| State | Published - Dec 13 2018 |
Bibliographical note
Publisher Copyright:© 2018 American Physical Society.
Funding
We gratefully acknowledge the support of the U.S. Department of Energy Office of Nuclear Physics through Grants No. DE-AC52-06NA25396, No. DE-FG02-03ER41258, No. DE-SC0014622, No. DE-AC-02-06CH11357, No. DE-AC05-00OR22725, and No. DE-SC0008107, the U.S. National Science Foundation through Grants No. PHY-1306547, No. PHY-1306942, No. PHY-1614545, No. PHY-0855584, No. PHY-0855610, No. PHY-1205833, No. PHY-1506021, No. PHY-1205393, and No. PHY-0855694, PAPIIT-UNAM Grants No. IN110410, No. IN11193, and No. IG1011016, CONACYT Grant No. 080444, the Natural Sciences and Engineering Research Council of Canada (NSERC) Grants No. SAPPJ/341298 and No. SAPEQ/375650, and the Canadian Foundation for Innovation (CFI). This research used resources of the Spallation Neutron Source of Oak Ridge National Laboratory, a DOE Office of Science User Facility. J.\u2009F., R.\u2009C.\u2009G., J.\u2009M., W.\u2009M.\u2009S., and Z.\u2009T. acknowledge support from the Indiana University Center for Spacetime Symmetries. S.\u2009S. acknowledges support from the German Academic Exchange Service (DAAD).
| Funders | Funder number |
|---|---|
| Deutscher Akademischer Austauschdienst France | |
| Canada Foundation for Innovation | |
| Indiana University Center for Spacetime Symmetries | |
| Natural Sciences and Engineering Research Council of Canada | SAPPJ/341298, SAPEQ/375650 |
| Natural Sciences and Engineering Research Council of Canada | |
| U.S. Department of Energy Office of Nuclear Physics | DE-AC05-00OR22725, DE-AC52-06NA25396, DE-FG02-03ER41258, DE-SC0008107, DE-AC-02-06CH11357, DE-SC0014622 |
| Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica | 080444 |
| Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica | |
| U.S. Department of Energy Chinese Academy of Sciences Guangzhou Municipal Science and Technology Project Oak Ridge National Laboratory Extreme Science and Engineering Discovery Environment National Science Foundation National Energy Research Scientific Computing Center National Natural Science Foundation of China | PHY-0855584, PHY-0855694, IG1011016, PHY-1614545, 1812367, 1306547, PHY-1205833, PHY-1506021, 1205393, IN110410, IN11193, 1614545, PHY-1306547, 1205833, 0855610, PHY-1306942, 0855694, 0855584, 1306942, PHY-1205393, PHY-0855610 |
| U.S. Department of Energy Chinese Academy of Sciences Guangzhou Municipal Science and Technology Project Oak Ridge National Laboratory Extreme Science and Engineering Discovery Environment National Science Foundation National Energy Research Scientific Computing Center National Natural Science Foundation of China |
ASJC Scopus subject areas
- General Physics and Astronomy