Status and prospects of precision analyses withe+e−→W+W−

Abstract

e + e − → W + W − is an integral part of the global precision analysis program which is becoming more relevant after the discovery of the Higgs boson. We analyze the current situation of precision calculations of inclusive e + e − → W + W − observables, and study the prospects of incorporating them into the framework of global precision electroweak analyses in light of per-mil-level cross section measurements at proposed future facilities. We present expansion formulas for the observables, making the dependence on the inputs clear. Also, the calculation of new physics effects is demonstrated in the effective field theory framework for universal theories. We go beyond the triple-gauge-couplings parametrization, and illustrate the complementarity of e + e − → W + W − and other precision data at the observables level.

Effective theories of universal theories

“…Thus, in this case the barred fields do not correspond to the physical particles, and the anomalous TGC parameters defined here are not equivalent to the usually used ones defined for the physical particles. However, the barred parameters ∆ḡ Z 1 , ∆κ γ ,λ γ are more convenient for universal theories, since they can be used in parallel with the oblique parametersŜ,T , W, Y ; see [68] for a demonstration in e + e − → W + W − . We will work out the relations between ∆ḡ Z 1 , ∆κ γ ,λ γ and the anomalous TGC parameters in the Higgs basis, which agree with the usually adopted definitions, in section 4 [see (4.14c) and table 8].…”

“…As we have seen in section 4.1, the relevant Higgs basis couplings are correlated. The measurements of the TGCs are currently dominated by e + e − → W + W − at LEP2, for which an EFT calculation in the case of universal theories has been presented in [68]. On the other hand, measurement of the spectrum of h → Z + − , a very clean decay channel, will be sensitive to an overlapping set of SMEFT parameters.…”

“…The same parameters enter the e + e − → W + W − observables in the same limit ∆ 1,2,3 → 0. For example, translating the results in [68] into the parameterizations in this paper, we find that, at √ s = 200 GeV, the unpolarized cross section is shifted bȳ δ NP σ = −0.0374∆ḡ Therefore, the anomalous TGC parameters ∆ḡ Z 1 , ∆κ γ extracted from e + e − → W + W − observables are related to h → Z + − , when the precision electroweak constraints in the from of oblique parameters ∆ 1,2,3 → 0 are imposed. The latter can be done consistently when we restrict ourselves to the 16-dimensional subspace of the SMEFT parameter space that characterizes universal theories.…”

Sensitivities of prospective future e + e − colliders to decoupled new physics

“…For triple-gauge couplings (TGCs) we use the e + e − → W + W − cross-section rescalings at √ s = 200 and 500 GeV calculated in [62]. 7 Using the integration-by-parts identity…”

Degree Dispersion Increases the Rate of Rare Events in Population Networks

“…As a result, stochasticity can turn deterministically stable attractors into metastable states [1]. Examples of such extreme, rare events, which may be of key practical importance include population extinction [2][3][4][5][6], switching in gene regulatory networks [7][8][9][10], the arrival of biomolecules at small cellular receptors [11], and power-grid destabilization [12][13][14].…”