Measurement of the Mass Difference between Neutral Charm-Meson Eigenstates

(LHCb Collaboration)

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


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.

Original languageEnglish (US)
Article number231802
JournalPhysical Review Letters
Issue number23
StatePublished - Jun 14 2019

ASJC Scopus subject areas

  • General Physics and Astronomy


Dive into the research topics of 'Measurement of the Mass Difference between Neutral Charm-Meson Eigenstates'. Together they form a unique fingerprint.

Cite this