The dawn of the particle physics: Start of the LHC-ATLAS experiment

What is the mechanism in creating the mass of the elementally particles? What is the origin of the dark matter which fills the universe? Is there a hidden space-time dimensions other than our ordinary 3+1? These fundamental questions that have been unanswered over the decades are finally ready to be solved with the TeV energy scale proton–proton collider, LHC (large hadron collider), with the large multi-purpose detector called ATLAS (A Toroidal LHC Apparatus). The LHC finally restarted its operation at November 2009, after a long shutdown period following the incident in 2008. This article aims to address the basic intrinsic issues of the contemporary high energy particle physics, and will illustrate how ATLAS can shed a light on them. Generic explanations on LHC and ATLAS, and also on how the Japanese group is taking part in the large international collaboration are addressed.