$\Upsilon$ decay to two-charm quark jets as a Probe of the Color Octet Mechanism

Understand

We calculate the decay rate of bottomonium to two-charm quark jets $\Upsilon \to c \bar c$ at the tree level and one-loop level including color-singlet and color-octet $b \bar b$ annihilations.

• We find that the short distance coefficient of the color-octet piece is much larger than the color-singlet piece, and that the QCD correction will change the endpoint behavior of the charm quark jet.
• The color-singlet piece is strongly affected by the one-loop QCD correction.
• In contrast, the QCD correction to the color-octet piece is weak.