What Factors Affect the Lifetime of B+ and Bc Mesons?

[ghetom]

I'm trying to understand why the B_c meson (anti b and c) has a lifetime of 0.46 picoseconds whilst the B_s, B⁺ and B^- have lifetimes of ~1.6 picoseconds. Is this a density of states thing? or to do with the CKM elements?

Thanks for any help.

 

[Bill_K]

It seems to be at least partly due to more available decay channels for the Bc. They say the decay is dominated by decays of the charm quark (70 percent). And in addition to all the other things that quarks can do, the charm quark can decay to a strange. Which is a channel that would not be available in a meson that had strange to begin with.

 

[Vanadium 50]

One way to look at this is that there are three ways a Bc can decay (the b can decay, the c can decay, or the two can annihilate) vs. only one for the B0. The fact that the lifetime is a factor of three shorter is coincidence.