Editing Neutron (section)

=== Electric dipole moment ===
{{Main|Neutron electric dipole moment}}

The Standard Model of particle physics predicts a tiny separation of positive and negative charge within the neutron leading to a permanent [[electric dipole moment]].<ref name="sussex">
{{cite press release
 |date= 20 February 2006
 |title= Pear-shaped particles probe big-bang mystery
 |url= http://www.sussex.ac.uk/press_office/media/media537.shtml
 |publisher= [[University of Sussex]]
 |access-date= 2009-12-14
 |archive-date= 2011-06-07
 |archive-url= https://web.archive.org/web/20110607140456/http://www.sussex.ac.uk/press_office/media/media537.shtml
 |url-status= live
}}</ref> But the predicted value is well below the current sensitivity of experiments. From several [[list of unsolved problems in physics#High-energy physics/particle physics|unsolved puzzles in particle physics]], it is clear that the Standard Model is not the final and full description of all particles and their interactions. New theories going [[beyond the Standard Model]] generally lead to much larger predictions for the electric dipole moment of the neutron. Currently, there are at least four experiments trying to measure for the first time a finite neutron electric dipole moment, including:
* [[Cryogenic neutron EDM experiment]] being set up at the [[Institut Laue–Langevin]]<ref>[http://hepwww.rl.ac.uk/EDM/index_files/CryoEDM.htm A cryogenic experiment to search for the EDM of the neutron] {{Webarchive|url=https://web.archive.org/web/20120216171059/http://hepwww.rl.ac.uk/EDM/index_files/CryoEDM.htm |date=2012-02-16 }}. Hepwww.rl.ac.uk. Retrieved on 2012-08-16.</ref>
* n2EDM experiment under construction at the UCN source at the [[Paul Scherrer Institute]]<ref>[http://nedm.web.psi.ch/ Search for the neutron electric dipole moment at PSI: The n2EDM Project of the nEDM collaboration] {{Webarchive|url=https://web.archive.org/web/20150925151115/http://nedm.web.psi.ch/ |date=2015-09-25 }}. Nedm.web.psi.ch (2001-09-12). Retrieved on 2012-08-16.</ref>
* nEDM experiment being envisaged at the [[Spallation Neutron Source]]<ref>[http://www.phy.ornl.gov/nedm/ US nEDM ORNL experiment public page] {{Webarchive|url=https://web.archive.org/web/20170430055915/http://www.phy.ornl.gov/nedm |date=2017-04-30 }}. Retrieved on 2017-02-08.</ref><ref>[http://p25ext.lanl.gov/edm/edm.html SNS Neutron EDM Experiment] {{Webarchive|url=https://web.archive.org/web/20110210021529/http://p25ext.lanl.gov/edm/edm.html |date=2011-02-10 }}. P25ext.lanl.gov. Retrieved on 2012-08-16.</ref>
* nEDM experiment being built at the [[Institut Laue–Langevin]]<ref>{{cite journal | last=A.P. Serebrov | display-authors=et al.| title=New Measurements of the Neutron Electric Dipole Moment with the Petersburg Nuclear Physics Institute Double-Chamber Electric Dipole Moment Spectrometer | journal=Physics of Particles and Nuclei Letters | volume=12 | year=2015 | doi=10.1134/S1547477115020193 | pages=286-296}}</ref>