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Precision measurement of the mass difference between light nuclei and anti-nuclei

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 and anti-deuterons, and $^{3}{\rm He}$ and $^3\overline{\rm He}$ nuclei carried out with the ALICE (A Large Ion Collider Experiment) 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 confirm 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).
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Contributor : Sylvie Flores <>
Submitted on : Tuesday, October 13, 2015 - 3:02:51 PM
Last modification on : Friday, September 10, 2021 - 1:50:15 PM

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J. Adam, Laurent Aphecetche, A. Baldisseri, Guillaume Batigne, I. Belikov, et al.. Precision measurement of the mass difference between light nuclei and anti-nuclei. Nature Physics, Nature Publishing Group, 2015, 11, pp.811-814. ⟨10.1038/nphys3432⟩. ⟨in2p3-01215032⟩



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