2002/12/31 by Thomas Appelquist, Bogdan A. Dobrescu, Adam R. Hopper · 14 citations
Physics and Astronomy · #Boson #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Electron #Electroweak interaction #Fermion #Gauge (firearms) #Gauge boson #Gauge theory #Hypercharge #Large Hadron Collider #Lepton #Nuclear physics #Particle physics #Particle physics theoretical and experimental studies #Physics #Quark #Standard Model (mathematical formulation) #Tevatron #hep-ex #hep-ph
paper · pdf · doi:10.1103/physrevd.68.035012
published as Phys.Rev. D68 (2003) 035012 · 26 pages, 2 figures. A comparison with the LEP bounds on sneutrino resonances is included
arxiv created 2003/07/17 · openalex publication_date 2003/08/22 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study theoretical and experimental constraints on electroweak theories including a new color-singlet and electrically neutral gauge boson. We first note that the electric charges of the observed fermions imply that any such Z^\ensuremath' boson may be described by a gauge theory in which the Abelian gauge groups are the usual hypercharge along with another U(1) component in a kinetic-diagonal basis. Assuming that the observed quarks and leptons have generation-independent U(1) charges, and that no new fermions couple to the standard model gauge bosons, we find that their U(1) charges form a two-parameter family consistent with anomaly cancellation and viable fermion masses, provided there are at least three right-handed neutrinos. We then derive bounds on the Z^\ensuremath' mass and couplings imposed by direct production and Z-pole measurements. For generic charge assignments and a gauge coupling of electromagnetic strength, the strongest lower bound on the Z^\ensuremath' mass comes from Z-pole measurements, and is of the order of 1 TeV. If the new U(1) charges are proportional to B\ensuremath-L, however, there is no tree-level mixing between the Z and Z^\ensuremath', and the best bounds come from the absence of direct production at CERN LEP II and the Fermilab Tevatron. If the U(1) gauge coupling is one or two orders of magnitude below the electromagnetic one, these bounds are satisfied for most values of the Z^\ensuremath' mass.