@article{2f95f2e3843d4eafa231fe5cdf444d66,
title = "Measurement of the Mass Difference between Neutral Charm-Meson Eigenstates",
abstract = "We report a measurement of the mass difference between neutral charm-meson eigenstates using a novel approach that enhances sensitivity to this parameter. We use 2.3×106 D0→KS0π+π- decays reconstructed in proton-proton collisions collected by the LHCb experiment in 2011 and 2012. Allowing for CP violation in mixing and in the interference between mixing and decay, we measure the CP-averaged normalized mass difference xCP=[2.7±1.6(stat)±0.4(syst)]×10-3 and the CP-violating parameter Δx=[-0.53±0.70(stat)±0.22(syst)]×10-3. The results are consistent with CP symmetry. These determinations are the most precise from a single experiment and, combined with current world-average results, yield the first evidence that the masses of the neutral charm-meson eigenstates differ.",
author = "\{(LHCb Collaboration)\} and R. Aaij and \{Abell{\'a}n Beteta\}, C. and B. Adeva and M. Adinolfi and Aidala, \{C. A.\} and Z. Ajaltouni and S. Akar and P. Albicocco and J. Albrecht and F. Alessio and M. Alexander and \{Alfonso Albero\}, A. and G. Alkhazov and \{Alvarez Cartelle\}, P. and Alves, \{A. A.\} and S. Amato and Y. Amhis and L. An and L. Anderlini and G. Andreassi and M. Andreotti and Andrews, \{J. E.\} and F. Archilli and \{Arnau Romeu\}, J. and A. Artamonov and M. Artuso and K. Arzymatov and E. Aslanides and M. Atzeni and B. Audurier and S. Bachmann and Back, \{J. J.\} and S. Baker and V. Balagura and W. Baldini and A. Baranov and Barlow, \{R. J.\} and Barrand, \{G. C.\} and S. Barsuk and W. Barter and M. Bartolini and F. Baryshnikov and V. Batozskaya and B. Batsukh and A. Battig and V. Battista and A. Bay and F. Bedeschi and \{Calvo Gomez\}, M. and X. Vilasis-Cardona",
note = "Funding Information: We express our gratitude to our colleagues in the CERN accelerator departments for the excellent performance of the LHC. We thank the technical and administrative staff at the LHCb institutes. We acknowledge support from CERN and from the national agencies: CAPES, CNPq, FAPERJ and FINEP (Brazil); MOST and NSFC (China); CNRS/IN2P3 (France); BMBF, DFG, and MPG (Germany); INFN (Italy); NWO (Netherlands); MNiSW and NCN (Poland); MEN/IFA (Romania); MSHE (Russia); MinECo (Spain); SNSF and SER (Switzerland); NASU (Ukraine); STFC (United Kingdom); NSF (USA). We acknowledge the computing resources that are provided by CERN, IN2P3 (France), KIT and DESY (Germany), INFN (Italy), SURF (Netherlands), PIC (Spain), GridPP (United Kingdom), RRCKI and Yandex LLC (Russia), CSCS (Switzerland), IFIN-HH (Romania), CBPF (Brazil), PL-GRID (Poland), and OSC (USA). We are indebted to the communities behind the multiple open-source software packages on which we depend. Individual groups or members have received support from the AvH Foundation (Germany); EPLANET, Marie Sk{\l}odowska-Curie Actions, and ERC (European Union); ANR, Labex P2IO, OCEVU, and R{\'e}gion Auvergne-Rh{\^o}ne-Alpes (France); the Key Research Program of Frontier Sciences of CAS, CAS PIFI, and the Thousand Talents Program (China); RFBR, RSF, and Yandex, LLC (Russia); GVA, XuntaGal, and GENCAT (Spain); the Royal Society and the Leverhulme Trust (United Kingdom); and Laboratory Directed Research and Development program of LANL (USA). Publisher Copyright: {\textcopyright} 2019 CERN. for the LHCb Collaboration. Published by the American Physical Society under the terms of the »https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP.",
year = "2019",
month = jun,
day = "14",
doi = "10.1103/PhysRevLett.122.231802",
language = "English",
volume = "122",
journal = "Physical Review Letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "23",
}