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The charm of asymmetries or the asymmetries in charm (entangled edition)

The charm of asymmetries or the asymmetries in charm (entangled edition)


The study of difference between matter and antimatter (CP violation) is one of the most exciting fields at the frontier of fundamental physics research. It is driven by the question of what happened to the antimatter after the Big Bang. The mesons, particles that contain both matter and antimatter quarks are ideal laboratories for the discovery of CP violation. This proposal aims at looking for CP violation in decays of mesons containing one charm (or anti-)quark, the only type of mesons where CP violation has not yet been observed.

One of the objectives is to carry out a measurement of the matter-antimatter mixing and CP violation parameters in the most sensitive charm decay mode (D0->Kspipi) using the unprecedented charm data sample collected by the LHCb experiment at CERN. To achieve maximal precision of both measurements, external input from the unique Chinese flavour factory, BESIII, is crucial. Key attributes of the decays of the D meson, the strong phases and their variation across the phase space, require the use of quantum-entangled states that are accessible at BESIII. Usually, these quantities are measured in regions of the phase space, the definition of which is inspired by a model. Wrong definition of these regions would lead to dilution of the sensitivity of these measurements. We propose to measure these quantities at every point of the phase space to maximise the precision.

The second objective is to look for CP violation in the charm D0->(anti-)K*0KS decays with LHCb data ignoring time-dependent effects arising from matter-antimatter mixing. The three-body final state after an instant decay of the exited K*0 meson, K pi KS, will be studied using novel model-dependent and model independent methods, the former has been pioneered by the Manchester LHCb group, and the latter has not yet been tested. Currently, these decays have been highlighted by theorists as the most likely discovery channel for time-integrated CP violation in the charm system.
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Oxford Road
M13 9pl Manchester

United Kingdom

Activity type

Higher or Secondary Education Establishments

EU Contribution

€ 212 933,76

Project information

Grant agreement ID: 843363


Grant agreement signed

  • Start date

    15 August 2019

  • End date

    14 August 2021

Funded under:


  • Overall budget:

    € 212 933,76

  • EU contribution

    € 212 933,76

Coordinated by:


United Kingdom