In the early universe matter and antimatter were created in unequal amounts, leaving a universe that is predominately composed of matter. The reason for this matter-antimatter asymmetry is an open question that is intimately tied to CP symmetry (Sakharov, 1967).
The KOTO experiment at J-PARC aims to study CP-symmetry breaking in kaon decays. In particular, KOTO searches for the rare decay, KL → π⁰νν, which is sometimes called the "Golden Mode". The mode is CP-violating, with a theoretical branching ratio highly suppressed in the Standard Model at (2.94 ± 0.15)×10−¹¹. With a small theoretical uncertainty, this search is highly sensitive to new physics. During the analysis of 2021 data, no events were observed in the signal region, which allowed KOTO to set the best upper limit on BR(KL → π⁰νν) to date at < 2.01 × 10−⁹ (90% CL). This presentation will introduce the KOTO experimental project, describe the analysis of KL → π⁰νν, include details on secondary physics searches for dark matter, and introduce the next stage of the experiment project called KOTO-II.
Joseph Redeker, Postdoctoral Researcher, University of Chicago
Host: Susan Dittmer
Joan West
(847) 491-3645
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