Measurement of CP Violation in B^{0}→D^{+}D^{-} Decays

Area of Science:

• Particle Physics
• High-Energy Physics
• Quantum Mechanics

Background:

• CP violation is a fundamental asymmetry in particle physics.
• Understanding CP violation is crucial for explaining the matter-antimatter asymmetry in the universe.
• The B0→D+D- decay channel provides a sensitive probe for CP violation studies.

Purpose of the Study:

• To measure CP violation observables S and C in the B0→D+D- decay.
• To search for direct CP violation and CP violation in the interference between mixing and decay.
• To constrain higher-order Standard Model corrections.

Main Methods:

• Analysis of proton-proton collision data collected by the LHCb experiment at 7 and 8 TeV.
• Utilizing a flavor-tagged, decay-time-dependent analysis.
• Statistical analysis of a large dataset corresponding to an integrated luminosity of 3 fb⁻¹.

Main Results:

• Measured CP violation observable S = -0.54 ± 0.17.
• Measured direct CP violation observable C = 0.26 ± 0.18.
• Evidence for CP violation established at 4.0 standard deviations.
• Constrained the phase shift from higher-order Standard Model corrections to Δϕ = -0.16 ± 0.19 rad.

Conclusions:

• The study provides significant evidence for CP violation in the B0→D+D- decay.
• The results contribute to a more precise understanding of CP violation within the Standard Model.
• The findings offer insights into the subtle differences between matter and antimatter.