D meson

Good news: there is a theory to describe the strong interaction, the interactions that bind the constituents of protons and neutrons together and create the strong force. Bad news: Calculations using the theory can be made in only a limited selection of natural phenomena.

Never alone

Scientists have tuned models to describe the average properties of the mesons created in the fragmentation process, CDF watched what happens to the end of the string that remains immediately after the part connected to the heavy quark is broken.