Reconstructing $D$ mesons

Learning goals

• Relativistic kinematics.
• Mesons.

To prepare for this activity, you should already have looked at the activity on reconstructing particles from their decay products.

After you are familiar with those activities, use the download more data notebook and grab the Monte Carlo file that simulates the following decay:

Also grab the CLEO data file.

Your challenge is to reconstruct the $D^+$ meson in the Monte Carlo and then go to the data and see if you can find the $D^+$ in the same decay mode. Things to think about:

• Make sure you deal with all possible $K\pi\pi$ combinations.
• How much background is there under the peak in the data? How might you eliminate it? Can you eliminate all of it?
• Is there "structure" in the $K\pi$ systems? That is, when you plot the invariant mass of the $K\pi$ system, do you see any peaks?
• Can you find the other decay modes in the data that you have MC for?

Have fun and good luck!