Hadron Colliders

The high energy hadron machines, Tevatron and HERA (in fixed target mode with a wire target inserted into the proton beam halo), are already producing large numbers of B mesons. The LHC will produce even greater numbers. At the Tevatron the $b\bar b$ production rate is ${\cal O}(10^4){\rm\ Hz}$ and at LHC it will be ${\cal O}(10^5){\rm\ Hz}$compared to the $\simeq 4{\rm\ Hz}$ at SLAC and KEK. The problem in this approach is achieving high enough reconstruction and tagging efficiencies in order to extract a sufficient number of B's to measure CP violation. The LHC has an additional benefit over the Tevatron and HERA because with the increasing centre of mass energy the ratio of the $b\bar b$ cross section over the total inelastic cross section also increases. All the hadron machines also have the advantage that they can study B_s mesons.