Quark fusion

In one of his conjectures [23], de Broglie described the photon as resulting from the fusion of two spin- /2 particles, an electron and a positron (whose spins would add and charges cancel) or a neutrino and its antineutrino. Although de Broglie managed to derive Maxwell s equations from this model, his idea was not retained in further developments of quantum electrodynamics. But it was somehow revived in the standard model of quantum chromodynamics, where it is assumed that the strong interaction between quarks constitutive of nucleons is mediated by massless... 

The leading-order (LO) process for the production of a heavy quark Q with mass mq in hadronic collisions is flavor creation, i.e. quark-antiquark annihilation and gluon-gluon fusion... 

Fig. 3.6 Reading order diagrams for heavy-quark pair production (a) quark-antiquark annihilation (b)-(d) gluon-gluon fusion gg -> QQ...

We have seen in this section, that there occurred a short phase in the early universe when density and temperature was high enough for the fusion of hydrogen into heavier elements up to lithium and boron. Hydrogen (protons) was present since protons were formed form quark particles. Neutral hydrogen since the recombination age. However, the second constiment of water molecules, oxygen, was not formed dming these phases. In the next section we will describe the evolution of stars and see how elements heavier than lithium can be synthesized by thermonuclear fusion reactions inside stars. 

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