Difference between revisions
strong-cp
Status and infobox
- status:
—→ open - kind:
—→ problem - year:
—→ 1977 - statement:
—→ Why does the strong force appear to respect CP symmetry when the theory allows it to be broken?
Relations
- + related to dark-matter: The original curation links this problem to What dark matter is; the argument for the link has not been written yet.
Source +19 −0
+---
+title: The strong CP problem
+kind: problem
+status: open
+year: 1977
+statement: Why does the strong force appear to respect CP symmetry when the theory allows it to be broken?
+space: standard-model
+---
+Quantum chromodynamics has a parameter θ that could take any value, and the neutron's electric dipole moment bounds it below about 10^-10. The Peccei–Quinn mechanism explains the small value with a new particle, the axion, which is also a dark matter candidate. Axion searches are running now.
+
+## Related problems
+
+- The original curation links this problem to [[related::Problem:dark-matter|What dark matter is]]; the argument for the link has not been written yet.
+
+## Sources
+
+- [Wikipedia: Strong CP problem](https://en.wikipedia.org/wiki/Strong_CP_problem)
+
+[[Space:standard-model|The Standard Model's loose ends]] · [[Continent:physics|Physics]]
Revision 85 as rendered
Quantum chromodynamics has a parameter θ that could take any value, and the neutron's electric dipole moment bounds it below about 10^-10. The Peccei–Quinn mechanism explains the small value with a new particle, the axion, which is also a dark matter candidate. Axion searches are running now.
Related problems
- The original curation links this problem to What dark matter is; the argument for the link has not been written yet.