Fourth-generation signatures in D 0-;D¯ 0 mixing and rare D decays
Abstract
We study the effects of a fourth generation on D 0-D¯ 0 mixing and the rare decays D 0→ μ+μ-, D→ℓ +ℓ -X (where X is nonstrange), D→ πℓ +ℓ - and D→ ϱγ (or ωγ). D 0-D¯ 0 mixing can be as large as the experimental limit of 0.5%. The fourth generation can enhance the branching ratios for the rare decays by several orders of magnitude: it can be as large as 10 -9 for the decays D 0→ μ+μ-, D→ℓ +ℓ -X and D→ πℓ +ℓ -. The long-distance contribution to the radiative decays is estimated to be ∼ 10 -8 and is shown to be dominant in the three-generation model. The fourth generation can bring this branching ratio up to ∼ 10 -6.
- Publication:
-
Physics Letters B
- Pub Date:
- May 1988
- DOI:
- 10.1016/0370-2693(88)90994-X
- Bibcode:
- 1988PhLB..205..540B