Observation of D0-D0 mixing in e+e- collisions

Area of Science:

• Particle Physics
• High-Energy Physics
• Quantum Mechanics

Background:

• D(0) meson decays are crucial for testing the Standard Model.
• Understanding flavor oscillations, like D(0)-D(0) mixing, is key to probing New Physics.

Purpose of the Study:

• To investigate and quantify D(0)-D(0) mixing in the decay channel D(0) → K+π-.
• To measure the mixing parameters and the ratio of doubly Cabibbo-suppressed to Cabibbo-favored decay rates.

Main Methods:

• Analysis of a large dataset (976 fb(-1)) collected by the Belle detector at the KEKB e+e- collider.
• Precise measurement of decay rates and oscillation parameters.

Main Results:

• Observed significant evidence for D(0)-D(0) mixing, excluding the no-mixing hypothesis at 5.1 standard deviations.
• Measured mixing parameters x'(2) = (0.09 ± 0.22) × 10(-3) and y'=(4.6 ± 3.4) × 10(-3).
• Determined the ratio R(D) = (3.53 ± 0.13) × 10(-3).

Conclusions:

• The observation of D(0)-D(0) mixing is a robust finding.
• These precise measurements provide stringent constraints on theoretical models and may hint at physics beyond the Standard Model.