Related papers: Multiparticle Higgs and Vector Boson Amplitudes at…
We study Higgs boson pair production processes at future hadron and lepton colliders including the photon collision option in several new physics models; i.e., the two-Higgs-doublet model, the scalar leptoquark model, the sequential fourth…
Calculations of high-energy processes involving the production of a large number of particles in weakly-coupled quantum field theories have previously signaled the need for novel non-perturbative behavior or even new physical phenomena. In…
Measuring the Higgs couplings accurately at colliders is one of the best routes for finding physics Beyond the Standard Model (BSM). If the measured couplings deviate from the SM predictions, then this would give rise to energy-growing…
We perform a comprehensive study of on-shell recursion relations for Born amplitudes in spontaneously broken gauge theories and identify the minimal shifts required to construct amplitudes with a given particle content and spin quantum…
Vector boson scattering is a well known probe of electroweak symmetry breaking. Here we study a related process of two electroweak vector bosons scattering into a vector boson and a Higgs boson ($VV \rightarrow Vh, V=W,Z$). This process…
Using methods from effective field theory, we have recently developed a novel, systematic framework for the calculation of the cross sections for electroweak gauge-boson production at small and very small transverse momentum q_T, in which…
A recent calculation of the multi-Higgs boson production in scalar theories with spontaneous symmetry breaking has demonstrated the fast growth of the cross section with the Higgs multiplicity at sufficiently large energies, called…
We argue that in models with several high scales; e.g. in composite Higgs models or in gauge extensions of the Standard Model (SM), vector-like leptons can be likely produced in a relatively large $\sqrt{s}$ region of the phase space.…
Threshold amplitudes are considered for multi-particle production in $\phi^k$ and $O(N) ~\phi^4$ theories. It is found that the disappearance of tree-level threshold amplitudes of $2$ on-shell particles producing a large number of particles…
In this report we review recent developments in perturbation theory methods for gauge theories. We present techniques and results that are useful in the calculation of cross sections for processes with many final state partons which have…
The precise measurement of the Higgs boson properties requires a robust framework to parametrize possible deviations from Standard Model (SM) predictions in the most model-independent way possible. The Effective Field Theory (EFT) framework…
The ultraviolet completion is the Standard Model (SM) gauge-symmetric four-fermion couplings at the high-energy cutoff. Composite particles appear in the gauge symmetric phase in contrast with SM particles in the spontaneous…
Throughout this thesis, we investigate how effective field theories, combined with unitarization techniques, can be used to explore physics beyond the Standard Model, with particular emphasis on the dynamical origin of electroweak symmetry…
We explore new physics scenarios which are optimally probed through precision Higgs measurements rather than direct collider searches. Such theories consist of additional electroweak charged or singlet states which couple directly to or mix…
We consider one-loop amplitudes of a Higgs boson coupled to gluons in the limit of a large top quark mass. We treat the Higgs as the real part of a complex field phi that couples to the self-dual field strengths and compute the one-loop…
For realistic values of the Higgs boson mass the high temperature electroweak phase transition cannot be described perturbatively. The symmetric phase is governed by a strongly interacting $SU(2)$ gauge theory. Typical masses of excitations…
In the framework of quantum gravity propagating in large extra dimensions, the effects of virtual Kaluza-Klein graviton and graviscalar interference with Higgs boson production amplitudes are computed at linear colliders and Higgs…
Exploiting the fact that $W$ pair production in high-energy $\gamma \gamma$ collisions is very large, we use this process to trigger Higgs, $Z$ or photon radiation. We find that there are sizeable rising cross-sections for triple bosons…
We enumerate the micro-states in Higgs theories, addressing (i) the number of vacuum states and (ii) the appropriate measure in the quantum path integral. To address (i) we explicitly construct the set of ground state wave-functionals in…
A non-standard symmetry breaking sector may lead to derivative couplings of the Higgs boson and thereby to anomalous interactions with the electroweak gauge bosons. In the framework of gauge-invariant effective Lagrangians the resulting…