title: Light composite scalar in twelve-flavor QCD on the lattice.
abstract: On the basis of lattice simulations using highly improved staggered quarks for twelve-flavor QCD with several bare fermion masses, we observe a flavor-singlet scalar state lighter than the pion in the correlators of fermionic interpolating operators. The same state is also investigated using correlators of gluonic interpolating operators. Combined with our previous study that showed twelve-flavor QCD to be consistent with being in the conformal window, we infer that the lightness of the scalar state is due to infrared conformality. This result shed some light on the possibility of a light composite Higgs boson ("technidilaton") in walking technicolor theories.
authors.affiliation: Kobayashi-Maskawa Institute for the Origin of Particles and the Universe (KMI), Nagoya University, Nagoya 464-8602, Japan.
authors.forename: Yasumichi
authors.initials: Y
authors.lastname: Aoki
authors.forename: Tatsumi
authors.initials: T
authors.lastname: Aoyama
authors.forename: Masafumi
authors.initials: M
authors.lastname: Kurachi
authors.forename: Toshihide
authors.initials: T
authors.lastname: Maskawa
authors.forename: Kei-ichi
authors.initials: K
authors.lastname: Nagai
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohki
authors.forename: Enrico
authors.initials: E
authors.lastname: Rinaldi
authors.forename: Akihiro
authors.initials: A
authors.lastname: Shibata
authors.forename: Koichi
authors.initials: K
authors.lastname: Yamawaki
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamazaki