14 - RHIC and LHC

Summary

The road to RHIC

The roads to RHIC and the LHC are highly intertwined. The great experimental discoveries of the late 1960s and early 1970s – DIS in e–p, hard scattering in p–p collisions, J/Ψ – inspired a surge of proposals for new accelerators to study the new phenomena. Of key importance in this development were the two major theoretical discoveries: QCD in 1973 as the theory of the strong interactions; and the unification of electromagnetic and weak interactions by the Glashow-Weinberg-Salam model [95-97] a few years earlier. The Glashow-Weinberg-Salam model [100] added two new neutral particles to the unified “electroweak” interaction:

1. (i) a vector boson, Z⁰, as the carrier of a neutral current weak interaction, which predicted such previously unobserved reactions as v_µ + N → v_µ + hadrons, with no final state µ, via the exchange of a Z⁰;

2. (ii) a neutral scalar “Higgs” boson which “spontaneously” broke the electroweak symmetry of the gauge theory Lagrangian and gave mass to the Z⁰ and W± bosons while keeping the photon massless.

Brookhaven (BNL) was first in the accelerator competition [657,658]. In 1971, convinced by the success of the proton–proton collider concept at the CERN-ISR, BNL proposed a 200 x 200 GeV (later 400 x 400 GeV) p–p collider with a high luminosity of L = 10³³ cm^-2 s^-1 using superconducting magnets, the Intersecting Storage Accelerator, or ISABELLE.