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Measurement of (intrinsic) electric quadrupole moment of neutron?

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While there are amazing experimental boundaries for electric dipole moment of electron and neutron, for electric quadrupole moments I could only find for large nuclei.

It seems especially interesting for neutron - three charged quarks would give electric quadrupole, neutron is believed to have positive core/negative shell (e.g. https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.7.144 , http://www.actaphys.uj.edu.pl/fulltext?series=Reg&vol=30&page=119 , http://www.phys.utk.edu/neutron-summer-school/lectures/greene.pdf ), what being toward spin direction would again give electric quadrupole.

Could it be measured in some near future? What approaches could be used?

Update: While spin 1/2 particles should have zero electric quadrupole moment, for example https://journals.aps.org/prc/abstract/10.1103/PhysRevC.63.015202 states: "all models give a positive intrinsic quadrupole moment for the proton (...) Due to angular momentum selection rules, a spin J=1/2 nucleus, such as the nucleon, does not have a spectroscopic quadrupole moment; however, it may have an intrinsic quadrupole moment" - hence the question can be viewed as regarding such intrinsic electric quadrupole moment of neutron.

Visualization of the difference from https://slideplayer.com/slide/4813696/

This post imported from StackExchange Physics at 2025-04-19 17:26 (UTC), posted by SE-user Jarek Duda

asked Apr 14 in Experimental Physics by Jarek Duda (15 points) [ revision history ]
edited Apr 19 by Dilaton

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The ref you mention contrasts spectroscopic to intrinsic...

This post imported from StackExchange Physics at 2025-04-19 17:26 (UTC), posted by SE-user Cosmas Zachos

commented Apr 15 by Cosmas Zachos (370 points) [ no revision ]

@CosmasZachos yes I have noticed: "Due to angular momentum selection rules, a spin J=1/2 nucleus, such as the nucleon, does not have a spectroscopic quadrupole moment; however, it may have an intrinsic quadrupole moment" - so my question should be about intrinsic electric quadrupole moment of neutron, which probably is also nonzero (?)

This post imported from StackExchange Physics at 2025-04-19 17:26 (UTC), posted by SE-user Jarek Duda

commented Apr 15 by Jarek Duda (15 points) [ no revision ]

That should make it clearer, dismissing the spectroscopic one and said comment right from the start in the question....

This post imported from StackExchange Physics at 2025-04-19 17:26 (UTC), posted by SE-user Cosmas Zachos

commented Apr 15 by Cosmas Zachos (370 points) [ no revision ]

@CosmasZachos, you are right - I have updated the question

This post imported from StackExchange Physics at 2025-04-19 17:26 (UTC), posted by SE-user Jarek Duda

commented Apr 15 by Jarek Duda (15 points) [ no revision ]

Why indeed does a bound dud system not display quadrupole moment of the same manner?

I guess because there are charged gluons and virtual quarks involved into dud system.

commented Apr 20 by Vladimir Kalitvianski (102 points) [ no revision ]

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Also deuteron has strong electric quadruple moment ( en.wikipedia.org/wiki/… ). E.g. en.wikipedia.org/wiki/Proton_spin_crisis suggests we should be careful about spin-based arguments for baryons. Neutron quadrupole moment should be measured experimentally - but how difficult would it be?

This post imported from StackExchange Physics at 2025-04-19 17:26 (UTC), posted by SE-user Jarek Duda

commented Apr 14 by Jarek Duda (15 points) [ no revision ]

Review this, this, this, this, etc... It's a cottage industry.

This post imported from StackExchange Physics at 2025-04-19 17:26 (UTC), posted by SE-user Cosmas Zachos

commented Apr 14 by Cosmas Zachos (370 points) [ no revision ]

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