We present the first general analysis of New Physics contributions to the D0-D̅ 0 lifetime difference (equivalently ΔΓD). We argue that New Physics (NP) contributions to |ΔC|=1 processes can dominate the lifetime difference in the flavor SU(3) limit. We provide several specific examples of models that produce sizable effects in ΔΓD for realistic values of light quark masses, even if such NP contributions are undetectable in the current round of D0 decay experiments. This makes ΔΓD a viable observable for studies of indirect effects of New Physics.
PHYSICAL REVIEW LETTERS