#Boson x dark x boson update

Through the efforts of Presidents George H.W. In the years immediately after the Cold War ended in 1991, Russian scientists turned increasingly to Europe and the United States to remain involved in frontier research. Now it appears to be coming to at least a pause, if not an end. The past two decades may have been the apex of this cooperation. One of the many unfortunate consequences of Russia’s invasion of Ukraine is the collateral damage to international scientific cooperation. A consequence of our analysis is that the usual tree-level description with only three physical parameters (i.e., two gauge couplings and one gauge boson mixing angle) is not in general a justified zero order limit of the treatment including radiative corrections.ORCAS ISLAND, Wash. The spontaneous breaking of the gauge symmetry induces further mixing between the two gauge bosons and introduces a fourth independent physical parameter. Moreover, gab = 0 to all orders seems to require an exact symmetry. We establish the (one-loop) conditions on the matter content for gab = 0 (a value usually assumed in the literature) and we show that in the minimal extensions of the Standard Model with an extra U(1) symmetry the choice gab = 0 is not stable under radiative corrections induced by the standard Higgs fields.

We show that the quantum corrections to the 2N gauge charges, with N = number of fermions + number of scalars, can be absorbed in the redefinition of three independent gauge couplings (ga, gb, and gab). We analyze the structure of models with unbroken and spontaneously broken U(1)a × U(1)b gauge symmetry. This will make the FCC-ee a unique precision instrument to study the heaviest known particles (Z, W and H bosons and the top quark), offering great direct and indirect sensitivity to new physics. Combining concepts from past and present lepton colliders and adding a few novel elements, the FCC-ee design promises outstandingly high luminosity. Most of the FCC-ee infrastructure could be reused for FCC-hh.

FCC-ee can be built with today’s technology. After summarizing the physics discovery opportunities, it presents the accelerator design, performance reach, a staged operation scenario, the underlying technologies, civil engineering, technical infrastructure, and an implementation plan. This document constitutes the second volume of the FCC Conceptual Design Report, devoted to the electron-positron collider FCC-ee. The FCC study also investigates an LHC energy upgrade, using FCC-hh technology. The scientific capabilities of the integrated FCC programme would serve the worldwide community throughout the 21st century. This study covers a highest-luminosity high-energy lepton collider (FCC-ee) and an energy-frontier hadron collider (FCC-hh), which could, successively, be installed in the same 100 km tunnel.

#Boson x dark x boson update

In response to the 2013 Update of the European Strategy for Particle Physics, the Future Circular Collider (FCC) study was launched, as an international collaboration hosted by CERN.