Collisions at LHC Proton-Proton Protons/bunch 1011 Beam energy 7 TeV(7x1012 ev) Luminosity 1034cm2s1 Bunch Event rate in ATLAS Proton N=LX o(pp) 109 interactions/s Mostly soft( lOw Pr)events Parton Interesting hard (high-pt)events are rare (quark, gluon) Higgs Particle ggs Selection of 1 in 10000,000,000,000 SUSY 童国梁,桂林,2006.10.28-11.1 会员代表大公少 very powerful detectors needed童国梁,桂林,2006.10.28-11.1 高能物理学会第七届全国 会员代表大会暨学术年会 5 Event rate in ATLAS : N = L x s (pp)  109 interactions/s Mostly soft ( low pT ) events Interesting hard (high-pT ) events are rare → very powerful detectors needed