Observation of the Mass Difference between Neutral Charm-Meson Eigenstates.
Phys Rev Lett
; 127(11): 111801, 2021 Sep 10.
Article
in En
| MEDLINE
| ID: mdl-34558945
ABSTRACT
A measurement of mixing and CP violation in neutral charm mesons is performed using data reconstructed in proton-proton collisions collected by the LHCb experiment from 2016 to 2018, corresponding to an integrated luminosity of 5.4 fb^{-1}. A total of 30.6 million D^{0}âK_{S}^{0}π^{+}π^{-} decays are analyzed using a method optimized for the measurement of the mass difference between neutral charm-meson eigenstates. Allowing for CP violation in mixing and in the interference between mixing and decay, the mass and decay-width differences are measured to be x_{CP}=[3.97±0.46(stat)±0.29(syst)]×10^{-3} and y_{CP}=[4.59±1.20(stat)±0.85(syst)]×10^{-3}, respectively. The CP-violating parameters are measured as Δx=[-0.27±0.18(stat)±0.01(syst)]×10^{-3} and Δy=[0.20±0.36(stat)±0.13(syst)]×10^{-3}. This is the first observation of a nonzero mass difference in the D^{0} meson system, with a significance exceeding seven standard deviations. The data are consistent with CP symmetry and improve existing constraints on the associated parameters.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Phys Rev Lett
Year:
2021
Document type:
Article
Affiliation country:
Netherlands
Publication country:
EEUU
/
ESTADOS UNIDOS
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ESTADOS UNIDOS DA AMERICA
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EUA
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UNITED STATES
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UNITED STATES OF AMERICA
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US
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USA