is a Standard Model particle with (u, d, b) quark content. What are the electric charge, baryon number and lepton number of this particle? Is this the only particle expected to exist with this quark content? Justify your answer
I know that the overall charge is 0, baryon number is 1. But what is the lepton number? ( The answer is 0) . Why is it 0? Why is it not the only expected particle with this quark content?