Model independent constraints on charges of new particles

Abstract

Any particle that is charged under SU (3) C and U (1) EM can mediate the gg → γγ process through loops. Near the threshold for the new particle pair production, gauge boson exchanges necessitate the resummation of ladder diagrams. We discuss the leading log order matching of the one-loop result with non-relativistic effective theory resummed result. We show how the diphoton invariant mass spectrum varies depending on decay width, color representation and electric charge of the new particle. The exclusion limits on the product of SU (3) C and U (1) EM charges of the new scalar or fermion particle are obtained from current LHC data. *

Radiative electroweak symmetry breaking models

“…In doing so, we can extend the model to be valid up to the Planck scale. Two loop computation confirms the validity of the computation [5]. Now the Higgs potential has non-analytic form…”

“…This prediction on Higgs self couplings is changed if the higher derivatives of the beta function are taken into account. Nevertheless, still significant enhancement of Higgs cubic coupling with respect to the SM prediction is expected, ranging from 20% (perturbative all the way to the Planck scale) to 80% (perturbative to 10 TeV) [5]. Though much dramatic deviation is predicted for Higgs quartic coupling, it looks extremely difficult to measure it experimentally and we focus on Higgs cubic coupling here.…”

“…Available online at www.sciencedirect.com In this Letter, the case with new mixed quartic coupling is considered [5]. Coleman-Weinberg mechanism sets the coefficient of the Higgs quadratic term to be zero at the origin of the potential, m 2 = 0.…”

“…More precise formulation can be found in [5]. The physical Higgs mass in the vacuum for the Higgs field in the unitary gauge…”

Heavy fermion bound states for diphoton excess at 750 GeV — collider and cosmological constraints

“…The other one is from excited 1 S0 bound states and those give another ∼ 50% enhancement [37]. Contribution from continuum states above the threshold is negligible when YX 2 [38].…”