Precision measurement of the mass difference between light nuclei and anti-nuclei.
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Precision measurement of the ...
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Abstract
The measurement of the mass differences for systems bound by the strong force has reached a very high precision with protons and anti-protons. The extension of such measurement from (anti-)baryons to (anti-)nuclei allows one to probe any difference in the interactions between nucleons and anti-nucleons encoded in the (anti-)nuclei masses. This force is a remnant of the underlying strong interaction among quarks and gluons and can be described by effective theories, but cannot yet be directly derived from quantum chromodynamics. Here we report a measurement of the difference between the ratios of the mass and charge of deuterons (d) and anti-deuterons (d-bar ), and 3He and nuclei carried out with the ALICE (A Large Ion Collider Experiment)4 detector in Pb–Pb collisions at a centre-of-mass energy per nucleon pair of 2.76 TeV. Our direct measurement of the mass-over-charge differences confirms CPT invariance to an unprecedented precision in the sector of light nuclei. This fundamental symmetry of nature, which exchanges particles with anti-particles, implies that all physics laws are the same under the simultaneous reversal of charge(s) (charge conjugation C), reflection of spatial coordinates (parity transformation P) and time inversion (T).Citation
ALICE Collaboration (2015) 'Precision measurement of the mass difference between light nuclei and anti-nucle', Nature Physics, 11 (10):811Publisher
Springer NatureJournal
Nature PhysicsDOI
10.1038/nphys3432Additional Links
http://www.nature.com/articles/nphys3432Type
ArticleLanguage
enISSN
17452473EISSN
17452481ae974a485f413a2113503eed53cd6c53
10.1038/nphys3432