Search results for " Standard Model"
showing 10 items of 645 documents
Neutrino oscillation phenomenology in the standard model and beyond
2020
Over the last 20 years measurements of neutrino oscillation parameters have become very precise. In the standard neutrino oscillation picture most of the parameters are measured at the percent level. In this thesis we study neutrino oscillations in the standard picture and beyond. We analyze data from all types of neutrino oscillation experiments to obtain a global picture of neutrino oscillations. The remaining unknowns in the standard picture are the value of the CP-violating phase $\delta$, the octant of the atmospheric angle $\theta_{23}$ and the neutrino mass ordering. We discuss the current status of these unknowns and also comment on how well future experiments will do in measuring t…
Precision tests of QED and non-standard models by searching photon-photon scattering in vacuum with high power lasers
2009
We study how to search for photon-photon scattering in vacuum at present petawatt laser facilities such as HERCULES, and test Quantum Electrodynamics and non-standard models like Born-Infeld theory or scenarios involving minicharged particles or axion-like bosons. First, we compute the phase shift that is produced when an ultra-intense laser beam crosses a low power beam, in the case of arbitrary polarisations. This result is then used in order to design a complete test of all the parameters appearing in the low energy effective photonic Lagrangian. In fact, we propose a set of experiments that can be performed at HERCULES, eventually allowing either to detect photon-photon scattering as du…
Search for new particles in two-jet final states in 7 TeV proton-proton collisions with the ATLAS detector at the LHC
2010
19 páginas, 2 figuras, 1 tabla.-- et al.(ATLAS Collaboration).
Supersymmetry parameter analysis: SPA convention and project.
2005
18 páginas, 6 figuras, 12 tablas.-- et al.
Low-energy symmetries of QCD and the structure of the nucleon
2015
Abstract We present some updated results regarding the scalar and electromagnetic structure of the nucleon obtained by the relativistic formulation of chiral effective field theory with baryons. We compare them with previous determinations available in the literature, and show their relevance for searches of physics beyond the standard model in the low energy frontier.
Low energy structure of the nucleon from chiral effective field theory
2014
We present some updated results regarding the scalar and electromagnetic structure of the nucleon obtained by the relativistic formulation of chiral effective field theory with baryons. We compare them with previous determinations available in the literature, and show their relevance for searches of physics beyond the standard model in the low energy frontier. An accurate knowledge of the structure of the nucleon is important to improve our understanding of the funda- mental interactions and provide theoretical estimations of some important quantities with a small uncertainty. This is specially relevant for experiential searches of physics be- yond the standard model in the low energy front…
From Type II string theory towards BSM/dark sector physics
2016
Four-dimensional compactifications of string theory provide a controlled set of possible gauge representations accounting for BSM particles and dark sector components. In this review, constraints from perturbative Type II string compactifications in the geometric regime are discussed in detail and then compared to results from heterotic string compactifications and non-perturbative/non-geometric corners. As a prominent example, an open string realization of the QCD axion is presented. The status of deriving the associated low-energy effective action in four dimensions is discussed and open avenues of major phenomenological importance are highlighted. As examples, a mechanism of closed strin…
Explaining 750 GeV diphoton excess from top/bottom partner cascade decay in two-Higgs-doublet model extension
2016
In this paper, we interpret the 750 GeV diphoton excess in the Zee-Babu extension of the two-Higgs-doublet model by introducing a top partner ($T$)/bottom partner ($B$). In the alignment limit, the 750 GeV resonance is identified as the heavy CP-even Higgs boson ($H$), which can be sizably produced via the QCD process $pp \to T\bar{T}$ or $pp \to B\bar{B}$ followed by the decay $T\to Ht$ or $B \to Hb$. The diphoton decay rate of $H$ is greatly enhanced by the charged singlet scalars predicted in the Zee-Babu extension and the total width of $H$ can be as large as 7 GeV. Under the current LHC constraints, we scan the parameter space and find that such an extension can account for the observe…
The decay
2010
In this paper the potential for the discovery of new physics in the exclusive decay B ¯ d → K ¯ ⁎ 0 μ + μ − is discussed. Attention is paid to constructing observables which are protected from uncertainties in QCD form factors and at the same time observe the symmetries of the angular distribution. We discuss the sensitivity to new physics in the observables including the effect of CP-violating phases.
Tau lepton physics: theory overview
1996
20 páginas, 5 figuras, 11 tablas.-- Comunicación presentada en la 4ª International Workshop on Tau Lepton Physics (TAU96), Colorado, September 1996.-- arXiv:hep-ph/9612308v1