10,139 research outputs found
Top quark FCNC couplings at future circular hadron electron colliders
A study of single top quark production via flavor changing neutral current
interactions at vertices is performed at future circular hadron
electron collider. The signal cross sections for the processes and in the collision of electron
beam with energy 60 GeV and proton beam with energy 50 TeV are
calculated. In the analysis, the invariant mass distributions of three jets
reconstructing top quark mass, requiring one b-tagged jet and other two jets
reconstructing the mass are used to count signal and background events
after all selection cuts. The upper limits on the anomalous flavor changing
neutral current couplings are found to be 0.01 at
future circular hadron electron collider for fb with the
fast simulation of detector effects. Signal significance depending on the
couplings is analyzed and an enhanced sensitivity is found to the
branching ratio BR() at the future circular hadron electron
collider when compared to the current experimental results.Comment: 11 pages, 4 Figures, 4 Tables, to appear in Phys. Rev.
Anomalous resonant production of the fourth family up type quarks at the LHC
Considering the present limits on the masses of fourth family quarks from the
Tevatron experiments, the fourth family quarks are expected to have mass larger
than the top quark. Due to their expected large mass they could have different
dynamics than the quarks of three families of the Standard Model. The resonant
production of the fourth family up type quark t' has been studied via anomalous
production subprocess gq_i-->t' (where q_i=u,c) at the LHC with the center of
mass energy 10 TeV and 14 TeV. The signatures of such process are discussed
within the SM decay modes. The sensitivity to anomalous coupling
\kappa/\Lambda=0.1 TeV^(-1) can be reached at \sqrt{s}=10 TeV and L_int=100
pb^(-1).Comment: 14 pages, 13 figures, 7 table
Probing Charged Higgs Boson Couplings at the FCC-hh Collider
Many of the new physics models predicts a light Higgs boson similar to the
Higgs boson of the Standard Model (SM) and also extra scalar bosons. Beyond the
search channels for a SM Higgs boson, the future collider experiments will
explore additional channels that are specific to extended Higgs sectors. We
study the charged Higgs boson production within the framework of two Higgs
doublet models (THDM) in the proton-proton collisions at the FCC-hh collider.
With an integrated luminosity of 500 fb at very high energy frontier, we
obtain a significant coverage of the parameter space and distinguish the
charged Higgs-top-bottom interaction within the THDM or other new physics
models with charged Higgs boson mass up to 1 TeV.Comment: 22 pages, 26 figures, 6 table
Quantum Electrodynamic Theory of Few-Electron Highly Charged Ions
In this thesis, quantum electrodynamic (QED) effects in few-electron highly charged ions are investigated. The interaction of the electron with the nucleus is taken into account in a nonperturbative manner. A versatile approach to accurately calculate self-energy corrections combining finite basis sets with analytical methods is presented. The approach is applicable to many-electron ions using the screening-potential approximation. The method is applied to calculate self-energy corrections to the energy level of the electron in the 4d3/2 state of 131Xe17+ and to the excitation energy of the 4d -> 4f excitation in 187Re29+. QED corrections to the g factor of lithiumlike and boronlike ions in a wide range of nuclear charges are presented. Many-electron contributions as well as radiative effects on the one-loop level are calculated. Contributions resulting from the interelectronic interaction, derived in a QED framework, and most of the terms of the vacuum polarization effect are evaluated to all orders in the nuclear coupling strength Zα. Uncertainties resulting from nuclear size effects, numerical calculations, and uncalculated effects are discussed. Finally, a new approach to determine the fine-structure constant α using a weighted difference of the bound electron g factor and energy in hydrogenlike systems is put forward. It is shown that nuclear structural effects are sufficiently well suppressed while sensitivity to α is enhanced in this weighted difference, as compared to the g factor
Access to improve the muon mass and magnetic moment anomaly via the bound-muon factor
A theoretical description of the factor of a muon bound in a nuclear
potential is presented. One-loop self-energy and multi-loop vacuum polarization
corrections are calculated, taking into account the interaction with the
binding potential exactly. Nuclear effects on the bound-muon factor are
also evaluated. We put forward the measurement of the bound-muon factor via
the continuous Stern-Gerlach effect as an independent means to determine the
free muons magnetic moment anomaly and mass. The scheme presented enables to
increase the accuracy of the mass by more than an order of magnitude
Hadronic vacuum polarization correction to atomic energy levels
The shift of atomic energy levels due to hadronic vacuum polarization is evaluated in a semiempirical way for hydrogenlike ions and for muonic hydrogen. A parametric hadronic polarization function obtained from experimental crosssections of e- e+ annihilation into hadrons is applied to derive an effective relativistic Uehling potential. The energy corrections originating from hadronic vacuum polarization are calculated for low-lying levels using analytical Dirac-Coulomb wave functions, as well as bound wave functions accounting for the finite nuclear size. Closed formulas for the hadronic Uehling potential of an extended nucleus as well as for the relativistic energy shift in case of a point-like nucleus are derived. These results are compared to existing analytic formulas from non-relativistic theory
Genetics of rust resistance in the Australian wheat germplasm
The aim of this naturalistic study was to identify pretreatment predictors of response to cognitive behaviour therapy in treatment-seeking patients with binge eating disorder (BED; N=304). Furthermore, we examined end-of-treatment factors that predict treatment outcome 6months later (N=190). We assessed eating disorder psychopathology, general psychopathology, personality characteristics and demographic variables using self-report questionnaires. Treatment outcome was measured using the bulimia subscale of the Eating Disorder Inventory 1. Predictors were determined using hierarchical linear regression analyses. Several variables significantly predicted outcome, four of which were found to be both baseline predictors of treatment outcome and end-of-treatment predictors of follow-up: Higher levels of drive for thinness, higher levels of interoceptive awareness, lower levels of binge eating pathology and, in women, lower levels of body dissatisfaction predicted better outcome in the short and longer term. Based on these results, several suggestions are made to improve treatment outcome for BED patients
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