ananyo (2519492) writes Scientists at the Institute of High Energy Physics (IHEP) in Beijing, working with international collaborators, are planning to build a "Higgs factory" by 2028 — a 52-kilometer underground ring that would smash together electrons and positrons. Collisions of these fundamental particles would allow the Higgs boson to be studied with greater precision than at the much smaller (27 km) Large Hadron Collider at CERN, Europe's particle-physics laboratory near Geneva, Switzerland. Physicists say that the proposed US$3-billion machine is within technological grasp and is considered conservative in scope and cost. But China hopes that it would also be a stepping stone to a next-generation collider — a super proton-proton collider — in the same tunnel. The machine would be a big leap for China. The country's biggest current collider is just 240 meters in circumference.