Search

Abstract: We study the production cross section of the t-channel single top quark at the LHC in the noncommutative space–time. It is shown that the deviation of the t-channel single top cross section from the Standard Model value because of noncommutativity is significant when . Using the present experimental precision in measurement of the t-channel cross section, we apply upper limit on the noncommutative parameter. When a single top quark decays, there is a significant amount of angular correlation, in the top quark rest frame between the top spin direction and the direction of the charged lepton momentum from its decay. We study the effect of noncommutativity on the spin correlation and we find that depending on the noncommutative scale, the angular correlation can enhance considerably. Then, we provide limits on the noncommutative scale for various possible relative uncertainties on the spin correlation measurement. [Copyright &y& Elsevier]

Abstract: 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. [ABSTRACT FROM AUTHOR]