Heavy flavours production

S. Frixione, P. Nason, B.R. Webber, Matching NLO QCD and parton showers in heavy flavour production. JHEP 0308, 007 (2003)... 

The subject of heavy flavours has e3q>anded tremendously in recent years stretching from the static properties (mainly spectroscopy, i.e. energy levels, lifetimes, branching ratios, decays, mixing etc.) of hadrons with one or more heavy quarks, e.g. bottom or charm, to more dynamical properties (like fragmentation, structure functions, jets etc.) and on to more exotic topics, e.g. production and decay of as yet undiscovered flavours like top, or speculations on a fourth generation or imphcations on Higgs or on non-standard effects and so on. 

We note that if the electromagnetic and strong interactions conserve flavour, then we should expect associated production of heavy flavours, i.e. that production always occurs with pairs of particles of opposite charm or bottom (this is, of course, not the case for production in neutrino interactions via weak forces). Further, the decay of a heavy particle should be generated by the weak interactions, implying very narrow widths and effects of parity non conservation. 

The production of heavy flavours is a classical process in QCD and is linked with jet physics (Chapters 24, 25). Here, we limit ourselves to a few qualitative considerations. 

Fig. 13.19. Cross-section for bottom production (from Ellis and Keman, 1990). 13.5 Heavy flavours at LEP...

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The taste of freshly consumed mandarins is very juicy, sweet fresh with the characteristic heavy aromatic aldehydic flavour. The processed juice is not stable. Its flavour turns into an unpleasant phenolic skunky off flavour. The peel oil keeps its original aromatic sweet odour and is often used to modify orange flavourings into sweeter, more aromatic products. 

Because NC interactions do not change the quark flavour, the only way to produce heavy quarks in the final state is for the vector boson to interact with the heavy quark itself. As mentioned earlier it is sensible to assume that there is no primitive cor b content to a nucleon so that the process relies on QQ production by gluons, as illustrated in Fig. 16.10. 

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