A Possible Arena for Searching New Physics - the $\Gamma (D^0\to {\rho }^0\gamma )/\Gamma (D^0\to \omega \gamma )$ Ratio

Abstract

We propose to investigate flavour changing neutral currents in the $c\to u\gamma$ transition through the measurement of the difference between $\Gamma (D^0\to {\rho }^0\gamma )$ and $\Gamma (D^0\to \omega \gamma )$. This is based on the observation that $D^0\to (d\bar{d})\gamma$ is due to long distance physics while $D^0\to (u\bar{u})\gamma$ arises from the $c\to u\gamma$ transition. The effect of $\rho -\omega$ mixing is included. A difference in the decay widths of more than about 30% would be indicative of new physics.

Comments: 7 pages, 1 figure included