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Search Results: 1 - 10 of 31173 matches for " Martin Jung "
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A robust limit for the electric dipole moment of the electron
Jung, Martin
High Energy Physics - Phenomenology , 2013,
Abstract: Electric dipole moments constitute a competitive method to search for new physics, being particularly sensitive to new CP-violating phases. Given the experimental and theoretical progress in this field and more generally in particle physics, the necessity for more reliable bounds than the ones usually employed emerges. We therefore propose an improved extraction of the electric dipole moment of the electron and the relevant coefficient of the electron-nucleon coupling, taking into account theoretical uncertainties and possible cancellations, to be used in model-dependent analyses. Specifically, we obtain at 95% C.L. |d_e|<=0.14 10^{-26}e cm with present data, which is very similar to the bound typically quoted from the YbF molecule, but obtained in a more conservative manner. We examine furthermore in detail the prospects for improvements and derive upper limits for the dipole moments of several paramagnetic systems presently under investigation, i.e. Cesium, Rubidium and Francium.
LecoS - A QGIS plugin for automated landscape ecology analysis
Martin Jung
PeerJ , 2015, DOI: 10.7287/peerj.preprints.116v2
Abstract: The quantification of landscape structures is an important part in many ecological analysis dealing with GIS derived satellite data. This paper introduces a new free and open-source tool for conducting landscape ecology analysis. LecoS is able to compute a variety of basic and advanced landscape metrics in an automatized way by iterating through an optional provided vector layer. It is integrated into the QGIS processing framework and can thus be used as a stand-alone tool or within bigger complex models. Finally a potential case-study is demonstrated, which tries to quantify pollinators responses on landscape derived metrics at various scales.
The Electron EDM and EDMs in Two-Higgs-Doublet Models
Martin Jung
Physics , 2014,
Abstract: Electric dipole moments constitute highly sensitive probes for CP-violating effects beyond the Standard Model. The upper limits obtained in various precision experiments can therefore be used to strongly restrict new physics models. However, relating the experimental information to parameters of a specific model is complicated by the presence of various sources for EDMs as well as large theory uncertainties in some of the relevant matrix elements. In this article, we address both issues for the EDMs of heavy paramagnetic systems, where it is possible to include subleading contributions, thereby model-independently extracting the electron EDM. We furthermore use expressions for the presently phenomenologically relevant EDMs with conservative estimates for the theoretical uncertainties to place constraints on CP-violating phases in the context of Two-Higgs-Doublet models.
Determining weak phases from B->J/Psi P decays
Martin Jung
Physics , 2012, DOI: 10.1103/PhysRevD.86.053008
Abstract: The decay B -> J/Psi K_S remains the most important source of information for the B_d mixing phase, determined by the CKM angle beta in the standard model. When aiming at a precision appropriate for present and coming high luminosity colliders, the corresponding hadronic matrix elements are a major obstacle, as their precise calculation is still not feasible with existing methods. Flavour symmetries offer a possibility to extract them from data, however again with limited precision. In this article, we propose a framework to take subleading contributions in B_{u,d,s} -> J/Psi P decays into account, P=(pi,K,(eta_8)), using an SU(3) analysis, together with the leading corrections to the symmetry limit. This allows for a model-independent extraction of the B_d mixing phase adequate for coming high precision data, and additionally yields information on possible New Physics contributions in these modes. We find the penguin-induced correction to be small, |Delta S|<~0.01, a limit which can be improved with coming data on CP asymmetries and branching ratios. Finally, the sensitivity on the CKM angle gamma from these modes is critically examined, yielding a less optimistic picture than previously envisaged.
A robust limit for the electric dipole moment of the electron
Martin Jung
Physics , 2013, DOI: 10.1007/JHEP05(2013)168
Abstract: Electric dipole moments constitute a competitive method to search for new physics, being particularly sensitive to new CP-violating phases. Given the experimental and theoretical progress in this field and more generally in particle physics, the necessity for more reliable bounds than the ones usually employed emerges. We therefore propose an improved extraction of the electric dipole moment of the electron and the relevant coefficient of the electron-nucleon coupling, taking into account theoretical uncertainties and possible cancellations, to be used in model-dependent analyses. Specifically, we obtain at 95% C.L. |d_e|<=0.14 10^{-26}e cm with present data, which is very similar to the bound typically quoted from the YbF molecule, but obtained in a more conservative manner. We examine furthermore in detail the prospects for improvements and derive upper limits for the dipole moments of several paramagnetic systems presently under investigation, i.e. Cesium, Rubidium and Francium.
Branching ratio measurements and isospin violation in B-meson decays
Martin Jung
Physics , 2015, DOI: 10.1016/j.physletb.2015.12.024
Abstract: The approximate symmetry of the strong interactions under isospin transformations is among the most precise tools available to control hadronic matrix elements. It is crucial in extracting fundamental parameters, but also provides avenues for the search of phenomena beyond the Standard Model. The precision of the resulting predictions requires special care when determining the quantities they are to be tested with. Specifically, in the extraction of branching ratios often isospin symmetry is assumed at one point or another implicitly, implying a significant bias for precision analyses. We extract a bias-free value for the production asymmetry between charged and neutral $B$ meson pairs at $B$ factories and discuss its consequences for the determination of branching fractions generally, and isospin-violating observables like the rate asymmetries in B -> J/psi K or B -> K* gamma decays specifically.
Recent topics in CP violation
Martin Jung
Physics , 2012,
Abstract: Recent topics regarding CP violation in heavy meson systems are discussed. As an introduction, the status of the Unitarity Triangle fit and CP violation in B meson mixing are briefly reviewed. Two topics are covered in more detail: Penguin pollution in the "golden mode" B_d to J/psi K has gained importance due to the apparent smallness of new physics effects, together with the outstanding precision expected from present and future collider experiments. A very recent analysis is presented, which yields a stronger bound for the maximal influence of penguin contributions than previous analyses and shows the corresponding uncertainty to be reducible with coming data. Direct CP violation in hadronic charm decays received a lot of attention lately, due to a measurement by the LHCb collaboration yielding an unexpectedly large result. While this value is certainly not generically predicted in the Standard Model, it might be possible to accommodate it nevertheless. Therefore a method is discussed to use flavour symmetries to distinguish between this possibility and new physics.
Standard Model Predictions and New Physics Sensitivity in B->DD Decays
Martin Jung,Stefan Schacht
Physics , 2014, DOI: 10.1103/PhysRevD.91.034027
Abstract: An extensive model-independent analysis of B->DD decays is carried out employing SU(3) flavour symmetry, including symmetry-breaking corrections. Several theoretically clean observables are identified which allow for testing the Standard Model. These include the known time-dependent CP asymmetries, the penguin pollution of which can be controlled in this framework, but notably also quasi-isospin relations which are experimentally well accessible and unaffected by symmetry-breaking corrections. Theoretical assumptions can be kept to a minimum and controlled by additional sum rules. Available data are used in global fits to predict the branching ratio for the B0->DsDs decay as well as several CP asymmetries which have not been measured so far, and future prospects are analyzed.
Electric Dipole Moments in Two-Higgs-Doublet Models
Martin Jung,Antonio Pich
Physics , 2013, DOI: 10.1007/JHEP04(2014)076
Abstract: Electric dipole moments are extremely sensitive probes for additional sources of CP violation in new physics models. Specifically, they have been argued in the past to exclude new CP-violating phases in two-Higgs-doublet models. Since recently models including such phases have been discussed widely, we revisit the available constraints in the presence of mechanisms which are typically invoked to evade flavour-changing neutral currents. To that aim, we start by assessing the necessary calculations on the hadronic, nuclear and atomic/molecular level, deriving expressions with conservative error estimates. Their phenomenological analysis in the context of two-Higgs-doublet models yields strong constraints, in some cases weakened by a cancellation mechanism among contributions from neutral scalars. While the corresponding parameter combinations do not yet have to be unnaturally small, the constraints are likely to preclude large effects in other CP-violating observables. Nevertheless, the generically expected contributions to electric dipole moments in this class of models lie within the projected sensitivity of the next-generation experiments.
Covalent Anchoring of Chloroperoxidase and Glucose Oxidase on the Mesoporous Molecular Sieve SBA-15
Dirk Jung,Carsten Streb,Martin Hartmann
International Journal of Molecular Sciences , 2010, DOI: 10.3390/ijms11020762
Abstract: Functionalization of porous solids plays an important role in many areas, including heterogeneous catalysis and enzyme immobilization. In this study, large-pore ordered mesoporous SBA-15 molecular sieves were synthesized with tetraethyl orthosilicate (TEOS) in the presence of the non-ionic triblock co-polymer Pluronic P123 under acidic conditions. These materials were grafted with 3 aminopropyltrimethoxysilane (ATS), 3-glycidoxypropyltrimethoxysilane (GTS) and with 3 aminopropyltrimethoxysilane and glutaraldehyde (GA-ATS) in order to provide covalent anchoring points for enzymes. The samples were characterized by nitrogen adsorption, powder X-ray diffraction, solid-state NMR spectroscopy, elemental analysis, diffuse reflectance fourier transform infrared spectroscopy and diffuse reflectance UV/Vis spectroscopy. The obtained grafted materials were then used for the immobilization of chloroperoxidase (CPO) and glucose oxidase (GOx) and the resulting biocatalysts were tested in the oxidation of indole. It is found that enzymes anchored to the mesoporous host by the organic moieties can be stored for weeks without losing their activity. Furthermore, the covalently linked enzymes are shown to be less prone to leaching than the physically adsorbed enzymes, as tested in a fixed-bed reactor under continuous operation conditions.
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