Related papers: Z decays into light gluinos: a calculation based o…
A search for the decay of the Higgs boson to a $Z$ boson and a light, pseudoscalar particle, $a$, decaying respectively to two leptons and to two photons is reported. The search uses the full LHC Run 2 proton-proton collision data at…
We propose a decomposition of the S-matrix into individually gauge invariant sub-amplitudes, which are kinematically akin to propagators, vertices, boxes, etc. This decompsition is obtained by considering limits of the S-matrix when some or…
Depending on their masses, Supersymmetric particles can affect various measurements in Z decay. Among these are the total width (or consequent extracted value of $\alpha_s$), enhancement or suppression of various flavors, and left-right and…
The amplitude for scalar Higgs boson production in a fusion of two off-shell gluons is calculated including finite (not infinite) masses of quarks in the triangle loop. In comparison to the effective Lagrangian approach, we have found a new…
A search is performed for a new resonance decaying into a lighter resonance and a Z boson. Two channels are studied, targeting the decay of the lighter resonance into either a pair of oppositely charged tau leptons or a b b-bar pair. The Z…
The decay of the Standard Model Higgs boson in the intermediate-mass range into gluons is considered where special emphasis is put on the influence of the leading electroweak corrections proportional to G_F m_t^2. An effective Lagrangian…
In an extension of the Standard Model with one extra dimension and N=1 supersymmetry compactified on R^1/(Z_2 x Z'_2), we compute the Higgs boson decay width into two gluons, relevant to Higgs production in hadronic collisions. At one loop,…
Results are presented from a search for a narrow, spin-2 resonance decaying into a pair of Z bosons, with one Z-boson decaying into leptons (e+e- or mu+mu-) and the other into jets. An example of such a resonance is the Kaluza--Klein…
The amplitude for Higgs decay to two photons is calculated in renormalizable and unitary gauges using dimensional regularization at intermediate steps. The result is finite, gauge independent, and in agreement with previously published…
We revisit the one-loop calculation of the annihilation of a pair of the lightest neutralinos into a pair of photons, a pair of gluons and also a Z photon final state. For the latter we have identified a new contribution that may not always…
We apply the solution to the recursion relation for the double-off-shell quark current to the problem of computing one loop amplitudes with an arbitrary number of gluons. We are able to compute amplitudes for photon-gluon scattering,…
We provide two two-loop amplitudes relevant for precision Higgs physics. The first is the two-loop amplitude for Higgs boson production through gluon fusion with exact dependence on the top quark mass up to squared order in the dimensional…
Within the Minimal Supersymmetric Standard Model we study the three body decay of the lighter top squark into a b-quark, a W-boson and the lightest neutralino and compare this decay with the flavour changing two body decay of the lighter…
The presence of a light b-squark (with mass about 4 GeV) and gluino (with mass about 15 GeV) might explain the observed excess in b-quark production at the Tevatron. Though provocative, this model is not excluded by present data. The light…
Implications of a 2 - 5.5 GeV sbottom and 12 - 16 GeV gluino masses for rare B decay phenomenology are discussed. An effective Hamiltonian is constructed in which the gluinos are integrated out and a \tilde{b} squark remains among the light…
The one-loop calculation of the amplitude for the Higgs decay H-->\gamma\gamma\ due to virtual W's in the unitary gauge is presented. As the Higgs does not directly couple to the massless photons, the one-loop amplitude is finite. The…
The muon g-2 discrepancy between theory and experiment may be explained by a light vector boson Z_d that couples to the electromagnetic current via kinetic mixing with the photon. We illustrate how the existing electron g-2, pion Dalitz…
In this thesis we present an introduction to Soft-Collinear Effective Theory, which can be used to prove (or disprove) factorization theorems to all orders in the strong coupling constant for some B decays into light and energetic…
The Bc -> J/psi(Bs,Bs*)+ n pi decay amplitudes are calculated in the frame work of factorization model, which allows to represent this processes as Bc decay into J/psi Bs+W* followed by the virtual W*-boson decay into the final set of pi…
The exclusive decays of the Higgs boson to $B_c B_c$ and $B_c^\ast B_c^\ast$ pairs are studied. The hard parts of the decay amplitudes are estimated within the perturbative Standard Model up to one-loop corrections. The soft fusion of heavy…