Extra dimensions and Seesaw Neutrinos at the International Linear Collider

Tomoyuki Saito, Masaki Asano, Keisuke Fujii, Naoyuki Haba, Shigeki Matsumoto, Takehiro Nabeshima, Yosuke Takubo, Hitoshi Yamamoto, Koichi Yoshioka

Published 2010-08-13, updated 2010-11-27Version 2

We study the capability of the international linear collider (ILC) to probe extra dimensions via the seesaw mechanism. In the scenario we study, heavy Kaluza-Klein neutrinos generate tiny neutrino masses and, at the same time, have sizable couplings to the standard-model particles. Consequently, a Kaluza-Klein tower of heavy neutrinos (N) can be produced and studied at the ILC through the process: e+e- -> vN followed by N -> Wl decay. We show that the single lepton plus two-jets final states with large missing energy from this signal process will provide a good opportunity to measure the masses and cross sections of Kaluza-Klein neutrinos up to the third level. Furthermore, the neutrino oscillation parameters can be extracted from the flavor dependence of the lowest-mode signals, which give us information about the origin of low-energy neutrino masses.