Related papers: Two-loop mass splittings in electroweak multiplets…
New heavy particles in an SU(2)_L multiplet, sometimes introduced in extensions of the standard model, have highly degenerate tree-level mass M if their couplings to the Higgs bosons are very small or forbidden. However, loop corrections…
An electroweak multiplet stable due to a new global symmetry is a simple and well-motivated candidate for thermal dark matter. We study how direct searches at a future linear collider, such as the proposed CLIC, can constrain scalar and…
A review is given on the quantum correction $\Delta r$ in the $W$--$Z$ mass correlation at the electroweak two-loop level, as derived from the calculation of the muon lifetime in the Standard Model. Exact results for $\Delta r$ and the…
The radiatively-induced mass splitting between components of an electroweak multiplet is typically of order 100 MeV. This is sufficient to endow the charged components with macroscopically-observable lifetimes, and ensure an…
Electroweak loop corrections to the matrix elements for the spin-independent scattering of cold dark matter particles on nuclei are generally small, typically below the uncertainty in the local density of cold dark matter. However, as shown…
New physics could be explored through loop effects by the precision measurements at the Circular Electron Positron Collider due to its clean collision environment and high luminosity. In this work, we focus on two dark matter models that…
Recently exact results for the complete fermionic two-loop contributions to the prediction for the W-boson mass from muon decay in the electroweak Standard Model have been published [hep-ph/0007091]. This paper illustrates the techniques…
The leading electroweak MSSM two-loop corrections to the electroweak precision observables are calculated. They are obtained by evaluating the two-loop O(\alpha_t^2), O(\alpha_t \alpha_b), O(\alpha_b^2) contributions to the quantity…
The leading electroweak MSSM two-loop corrections to the $\rho$-parameter are calculated. They are obtained by evaluating the two-loop self-energies of the Z and the W boson at O(Gf^2 m_t^4) in the limit of heavy scalar quarks. A very…
We study scenarios where Dark Matter is a weakly interacting particle (WIMP) embedded in an ElectroWeak multiplet. In particular, we consider real SU(2) representations with zero hypercharge, that automatically avoid direct detection…
We consider a dark matter (DM) model that arises from the interplay of two simplified dark matter models, namely the doublet-triplet fermion model and the doublet-triplet scalar model. Despite being excellent exponents of the WIMP paradigm,…
Electroweak precision observables allow stringent tests of the Standard Model at the quantum level and imply interesting bounds on the mass of the Higgs boson through higher-order loop effects. Very significant constraints come especially…
We investigate the effect of fermionic electroweak multiplet dark matter models on the stability of the electroweak vacuum using two-loop renormalization group equations (RGEs) and one-loop matching conditions. Such a treatment is crucial…
A large class of viable dark matter models contain a WIMP candidate that is a component of a new electroweak multiplet whose mass $M$ is large compared to the electroweak scale $m_W$. A generic amplitude-level cancellation in such models…
We study the asymptotic behaviour of two-loop electroweak corrections at energies Q >> M_W, where logarithms of the type ln(Q/M_W) become dominant. The calculation of the leading and next-to-leading logarithmic terms for massless and…
The recent result of the higgs search at the LHC experiment has lead to more attention to the supersymmetric standard models with heavy sfermions. Among them, the models with the almost pure wino being the lightest supersymmetric particle…
Measurements of electroweak precision observables at future electron-positron colliders, such as the CEPC, FCC-ee, and ILC, will be sensitive to physics at multi-TeV scales. To achieve this sensitivity, precise predictions for the Standard…
The dominant electroweak two-loop corrections to the precision observables M_W and s_w^eff are calculated in the MSSM. They are obtained by evaluating the two-loop Yukawa contributions of O(alpha_t^2), O(alpha_t alpha_b), O(alpha_b^2) to…
We discuss the non-perturbative effects on the annihilation cross section of an Electro-Weak Dark Matter (EWDM) particle belonging to an electroweak multiplet when the splittings between the masses of the DM component and the other charged…
We derive logarithmically enhanced two-loop virtual electroweak corrections for arbitrary fermion-scattering processes at the TeV scale. This extends results previously obtained for massless fermion scattering to processes that involve also…