Structure of Nuclei and Nucleons

Abstract

In concluding this discussion it may be appropriate to return to the theme introduced earlier and raise the question once again of the deeper, and possibly philosophical, meaning of the term "elementary" particle. As we have seen, the proton and neutron, which were once thought to be elementary particles, are now seen to be highly complex bodies. It is almost certain that physicists will subsequently investigate the constituent parts of the proton and neutron-the mesons of one sort or another. What will happen from that point on? One can only guess at future problems and future progress, but my personal conviction is that the search for ever-smaller and ever-more-fundamental particles will go on as long as man retains the curiosity he has always demonstrated (29).

Ponderomotive snowplow electron acceleration with high energy tilted ultrafast laser pulses

“…or in terms of the normalized vector potential, a cap = √ 2|β pf |γ pf . In the simple non-relativistic limit, the capture threshold for the ponderomotive potential is simply equal to the classical kinetic energy 1 2 m e v 2 pf ; relativistically, the capture potential rises to infinity as v pf → c, the relativistic capture potential goes to infinity, showing that v pf must be less than c. In this moving frame, when the capture condition is satisfied, the electron 'reflects' from the potential and leaves with a momentum of the opposite sign. Transforming back to the lab frame, we find that for this onedimensional model, the maximum kinetic energy that a particle initially at rest can reach is E out = 4U cap p = m e c 2 a 2 cap .…”

“…Particle accelerators have led to some of the most important discoveries in fundamental physics [1][2][3][4][5][6] and practical applications [7][8][9][10]. The cost and physical scale of particle accelerators has motivated research into laser-based alternatives, focusing on accelerating low-mass electrons.…”

Towards a Muon Collider

“…Among the most relevant discoveries that did not proceed through the resonant production of new particles, there is the one of the inner structure of nucleons. This discovery could be achieved [62] only when the transferred energy in electron scattering could reach a significant fraction of the proton compositeness scale Λ qcd = 1/r p = 300 MeV. Proton-compositeness effects became sizeable enough to be detected at that energy, precisely because of the quadratic enhancement mechanism we described above.…”