• Prospects for triple gauge coupling measurements at future lepton colliders and the 14 TeV LHC

    分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-06-24

    摘要: The W W production is the primary channel to directly probe the triple gauge couplings. We first analyze the e (+) e (-) -> W (+) W (-) process at the future lepton collider, China's proposed Circular Electron-Positron Collider (CEPC). We use the five kinematical angles in this process to constrain the anomalous triple gauge couplings and relevant dimension six operators at the CEPC up to the order of magnitude of 10(-4). The most sensible information is obtained from the distributions of the production scattering angle and the decay azimuthal angles. We also estimate constraints at the 14 TeV LHC, with both 300 fb(-1) and 3000 fb(-1) integrated luminosity from the leading lepton p (T) and azimuthal angle difference Delta I center dot (ll) distributions in the di-lepton channel. The constrain is somewhat weaker, up to the order of magnitude of 10(-3). The limits on the triple gauge couplings are complementary to those on the electroweak precision observables and Higgs couplings. Our results show that the gap between sensitivities of the electroweak and triple gauge boson precision can be significantly decreased to less than one order of magnitude at the 14 TeV LHC, and that both the two sensitivities can be further improved at the CEPC.

  • Hidden confining world on the 750 GeV diphoton excess

    分类: 物理学 >> 基本粒子与场物理学 提交时间: 2016-06-24

    摘要: We explain the recent diphoton excesses around 750 GeV by both ATLAS and CMS as a singlet scalar Phi which couples to SM gluon and neutral gauge bosons only through higher-dimensional operators. A natural explanation is that Phi is a pseudo-Nambu-Goldstone boson (pNGB) which receives parity violation through anomaly if there exists a hidden strong dynamics. The singlet and other light pNGBs will decay into two SM gauge bosons and even serves as the metastable colored states which can be probed in the future. By accurately measuring their relative decay and the total production rate in the future, we will learn the underlying strong dynamics parameter. The lightest baryon in this confining theory could serve as a viable dark matter candidate.