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

Adam, J. and Antičić, Tome and Erhardt, Filip and Gotovac, S. and Planinić, Mirko and Poljak, Nikola and Simatović, Goran and Utrobičić, Antonija and Vicković, Linda and Zyzak, M. (ALICE Collaboration) (2015) Precision measurement of the mass difference between light nuclei and anti-nuclei. Nature Physics, 11. pp. 811-814. ISSN 1745-2481

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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(1,2). 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(3), 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) over bar), and He-3 and (3)(He) over bar 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(5,6). 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).

Item Type: Article
Keywords: spectroscopy, antihydrogen, antiproton, electron
Date: 2015
Subjects: NATURAL SCIENCES > Physics
Additional Information: © 2015 Macmillan Publishers Limited. This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Received 02 March 2015. Accepted 09 June 2015. Published online 17 August 2015.
Divisions: Faculty of Science > Department of Physics
Publisher: Macmillan Publishers Limited
Depositing User: Gordana Stubičan Ladešić
Date Deposited: 10 Mar 2018 16:24
Last Modified: 10 Mar 2018 16:24
URI: http://digre.pmf.unizg.hr/id/eprint/5779

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