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Rudolph, O.

Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)1994

Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)1994

AbstractAbstract

[en] In the theory of quantum chaos one studies the semiclassical behaviour of quantum mechanical systems whose corresponding classical counterparts exhibit chaos. These systems are sometimes considered as model systems in the theory of quantum chaos since they are well understood from a mathematical point of view. In this work we study the multifractal formalism for the geodesic flow on surfaces with constant negative curvature. The multifractal analysis of measures has been developed in order to characterize the scaling behaviour of measures on attractors of classical chaotic dynamical systems globally. In order to relate the multifractal formalism with quantities usually considered in the study of the geodesic flow on Riemann surfaces with constant negative curvature, it is necessary to establish the assertions of the multifractal formalism in a mathematically rigorous way. This is achieved with the help of the thermodynamic formalism for hyperbolic dynamical systems developed by Ruelle, Bowen and others. (orig.)

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Jul 1994; 110 p; ISSN 0418-9833;

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ANOMALOUS DIMENSION, BOUNDARY CONDITIONS, CLASSICAL MECHANICS, ENTROPY, ERGODIC HYPOTHESIS, FRACTALS, GEODESICS, HAUSDORFF SPACE, MEASURE THEORY, METRICS, QUANTUM MECHANICS, RIEMANN SPACE, SCALING LAWS, SCHROEDINGER EQUATION, SEMICLASSICAL APPROXIMATION, SERIES EXPANSION, STOCHASTIC PROCESSES, THERMAL EQUILIBRIUM, THERMODYNAMICS, TOPOLOGICAL MAPPING, TOPOLOGY, TRANSFER MATRIX METHOD

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Zhang, P.; Baboi, N.; Lorbeer, B.; Wamsat, T.; Eddy, N.; Fellenz, B.; Wendt, M.; Jones, R.M.

Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)2012

Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)2012

AbstractAbstract

[en] Beam-excited higher order modes (HOM) in accelerating cavities contain transverse beam position information. Previous studies have narrowed down three modal options for beam position diagnostics in the third harmonic 3.9 GHz cavities at FLASH. Localized modes in the beam pipes at approximately 4.1 GHz and in the fifth cavity dipole band at approximately 9 GHz were found, that can provide a local measurement of the beam position. In contrast, propagating modes in the first and second dipole bands between 4.2 and 5.5 GHz can reach a better resolution. All the options were assessed with a specially designed test electronics built by Fermilab. The aim is to de ne a mode or spectral region suitable for the HOM electronics. Two data analysis techniques are used and compared in extracting beam position information from the dipole HOMs: direct linear regression and singular value decomposition. Current experiments suggest a resolution of 50 m accuracy in predicting local beam position using modes in the fifth dipole band, and a global resolution of 20 m over the complete module. Based on these results we decided to build a HOM electronics for the second dipole band and the fifth dipole band, so that we will have both high resolution measurements for the whole module, and localized measurements for individual cavity. The prototype electronics is being built by Fermilab and planned to be tested in FLASH by the end of 2012.

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Aug 2012; 57 p; ISSN 0418-9833;

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Berggren, M.; Cakir, A.; Krueger, D.; List, J.; Lobanov, A.; Melzer-Pellmann, I.A.

Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)2013

Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)2013

AbstractAbstract

[en] Simplified models have become a widely used and important tool to cover the more diverse phenomenology beyond constrained SUSY models. However, they come with a substantial number of caveats themselves, and great care needs to be taken when drawing conclusions from limits based on the simplified approach. To illustrate this issue with a concrete example, we examine the applicability of simplified model results to a series of full SUSY model points which all feature a small τ -LSP mass difference, and are compatible with electroweak and flavor precision observables as well as current LHC results. Various channels have been studied using the Snowmass Combined LHC detector implementation in the Delphes simulation package, as well as the Letter of Intent or Technical Design Report simulations of the ILD detector concept at the ILC. We investigated both the LHC and ILC capabilities for discovery, separation and identification of all parts of the spectrum. While parts of the spectrum would be discovered at the LHC, there is substantial room for further discoveries and property determination at the ILC.

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Jul 2013; 27 p; ISSN 0418-9833;

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ANNIHILATION, ANTILEPTONS, CERN LHC, EFFECTIVE MASS, ELECTRON-POSITRON INTERACTIONS, HADRONS, INCLUSIVE INTERACTIONS, INTEGRAL CROSS SECTIONS, JET MODEL, MASS SPECTRA, MULTIPLE PRODUCTION, NONLUMINOUS MATTER, PAIR PRODUCTION, PARTICLE DISCRIMINATION, PROTON-PROTON INTERACTIONS, REST MASS, SPARTICLES, SUPERSYMMETRY, TEV RANGE 01-10, TEV RANGE 10-100

ACCELERATORS, ANTIMATTER, ANTIPARTICLES, BARYON-BARYON INTERACTIONS, CROSS SECTIONS, CYCLIC ACCELERATORS, ELEMENTARY PARTICLES, ENERGY RANGE, FERMIONS, HADRON-HADRON INTERACTIONS, INTERACTIONS, LEPTON-LEPTON INTERACTIONS, LEPTONS, MASS, MATHEMATICAL MODELS, MATTER, NUCLEON-NUCLEON INTERACTIONS, PARTICLE IDENTIFICATION, PARTICLE INTERACTIONS, PARTICLE MODELS, PARTICLE PRODUCTION, POSTULATED PARTICLES, PROTON-NUCLEON INTERACTIONS, SPECTRA, STORAGE RINGS, SYMMETRY, SYNCHROTRONS, TEV RANGE

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Alekhin, S.; Bluemlein, J.; Moch, S.

Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)2015

Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)2015

AbstractAbstract

[en] We present an improved determination of the up- and down-quark distributions in the proton using recent data on charged lepton asymmetries from W"± gauge-boson production at the LHC and Tevatron. The analysis is performed in the framework of a global fit of parton distribution functions. The fit results are consistent with a non-zero iso-spin asymmetry of the sea, x(anti d- anti u), at small values of Bjorken x∝10"-"4 indicating a delayed onset of the Regge asymptotics of a vanishing (anti d- anti u)-asymmetry at small-x. We compare with up- and down-quark distributions available in the literature and provide accurate predictions for the production of single top-quarks at the LHC, a process which can serve as a standard candle for the light quark flavor content of the proton.

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Aug 2015; 22 p; ISSN 0418-9833;

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BARYON-BARYON INTERACTIONS, BARYONS, BOSONS, COMPOSITE MODELS, ELEMENTARY PARTICLES, ENERGY RANGE, FERMIONS, FUNCTIONS, HADRON-HADRON INTERACTIONS, HADRONS, INTERACTIONS, INTERMEDIATE BOSONS, INTERMEDIATE VECTOR BOSONS, MATHEMATICAL MODELS, NUCLEON-ANTINUCLEON INTERACTIONS, NUCLEON-NUCLEON INTERACTIONS, NUCLEONS, PARTICLE INTERACTIONS, PARTICLE MODELS, PARTICLE PROPERTIES, POSTULATED PARTICLES, PROTON-NUCLEON INTERACTIONS, QUARK MODEL, QUARKS, TEV RANGE, TOP PARTICLES

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Baranov, S.P.; Zotov, N.P.

Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)2015

Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)2015

AbstractAbstract

[en] In the framework of k_t-factorization approach, the production and polarization of prompt ψ(2S) mesons in pp collisions at the LHC energies is studied. Our consideration is based on the non-relativistic QCD formalism for bound states and off-shell amplitudes for hard partonic subprocesses. The transverse momentum dependent (unintegrated) gluon densities in a proton were derived from Ciafaloni-Catani-Fiorani-Marchesini evolution equation or, alternatively, were chosen in accordance with Kimber-Martin-Ryskin prescription. The non-perturbative color-octet matrix elements were first deduced from the fits to the latest CMS data on ψ(2S) transverse momentum distributions and then applied to describe the ATLAS and LHCb data on ψ(2S) production and polarization at √(s)=7 TeV. We perform the estimation of polarization parameters λ_θ, λ_φ and λ_θ_φ which determine ψ(2S) spin density matrix and demonstrate that taking into account the off-shellness of initial gluons in the color-octet contributions leads to unpolarized ψ(2S) production at high transverse momenta, that is in qualitative agreement with the LHC data.

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Sep 2015; 19 p; ISSN 0418-9833;

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Numerical Data

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DENSITY MATRIX, DIFFERENTIAL CROSS SECTIONS, FACTORIZATION, GLUON-GLUON INTERACTIONS, INCLUSIVE INTERACTIONS, MATRIX ELEMENTS, PARTICLE PRODUCTION, PARTICLE STRUCTURE, POLARIZATION-ASYMMETRY RATIO, POLARIZED PRODUCTS, PROTON-PROTON INTERACTIONS, PROTONS, PSI-3685 MESONS, QUANTUM CHROMODYNAMICS, SCATTERING AMPLITUDES, SPIN ORIENTATION, TEV RANGE 01-10, THEORETICAL DATA, TRANSVERSE MOMENTUM

AMPLITUDES, BARYON-BARYON INTERACTIONS, BARYONS, BOSONS, CHARMONIUM, CROSS SECTIONS, DATA, DIMENSIONLESS NUMBERS, ELEMENTARY PARTICLES, ENERGY RANGE, FERMIONS, FIELD THEORIES, HADRON-HADRON INTERACTIONS, HADRONS, INFORMATION, INTERACTIONS, LINEAR MOMENTUM, MATRICES, MESONS, NUCLEON-NUCLEON INTERACTIONS, NUCLEONS, NUMERICAL DATA, ORIENTATION, PARTICLE INTERACTIONS, PROTON-NUCLEON INTERACTIONS, QUANTUM FIELD THEORY, QUARKONIUM, TEV RANGE, VECTOR MESONS

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Reuter, J.; Chokoufe Nejad, B.

Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)2016

Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)2016

AbstractAbstract

[en] State-of-the-art algorithms generate scattering amplitudes for high-energy physics at leading order for high-multiplicity processes as compiled code (in Fortran, C or C++). For complicated processes the size of these libraries can become tremendous (many GiB). We show that amplitudes can be translated to byte-code instructions, which even reduce the size by one order of magnitude. The byte-code is interpreted by a Virtual Machine with runtimes comparable to compiled code and a better scaling with additional legs. We study the properties of this algorithm, as an extension of the Optimizing Matrix Element Generator (O'Mega). The bytecode matrix elements are available as alternative input for the event generator WHIZARD. The bytecode interpreter can be implemented very compactly, which will help with a future implementation on massively parallel GPUs.

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Feb 2016; 6 p; ISSN 0418-9833;

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ALGORITHMS, ANNIHILATION, ANTIQUARKS, COMPUTER CALCULATIONS, COMPUTERIZED SIMULATION, DRELL MODEL, ELECTRON-POSITRON INTERACTIONS, ELECTRONS, FORTRAN, GLUON-GLUON INTERACTIONS, GLUONS, MATRIX ELEMENTS, MULTIPLE PRODUCTION, OPTIMIZATION, PAIR PRODUCTION, PARALLEL PROCESSING, POSITRONS, QUARK-ANTIQUARK INTERACTIONS, SCATTERING AMPLITUDES, W CODES

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McDonough, Evan; Scalisi, Marco

Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)2016

Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)2016

AbstractAbstract

[en] We develop a new class of supergravity cosmological models where inflation is induced by terms in the Kaehler potential which mix a nilpotent superfield S with a chiral sector Φ. As the new terms are non-(anti)holomorphic, and hence cannot be removed by a Kaehler transformation, these models are intrinsically Kaehler potential driven. Such terms could arise for example due to a backreaction of an anti-D3 brane on the string theory bulk geometry. We show that this mechanism is very general and allows for a unified description of inflation and dark energy, with controllable SUSY breaking at the vacuum. When the internal geometry of the bulk field is hyperbolic, we prove that small perturbative Kaehler corrections naturally lead to α-attractor behaviour, with inflationary predictions in excellent agreement with the latest Planck data.

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Sep 2016; 10 p; ISSN 0418-9833;

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Bargheer, Till

Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)2016

Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)2016

AbstractAbstract

[en] We review the systematics of Mandelstam cut contributions to planar scattering amplitudes in the multi-Regge limit. Isolating the relevant cut terms, we explain how the BFKL expansion can be used to construct the perturbative n-point multi-Regge limit amplitude in certain kinematic regions from a finite number of basic building blocks. At three loops and at leading logarithmic order, two building blocks are required. These are extracted from the known three-loop six-point and seven-point symbols for general kinematics. The subleading and sub-subleading terms require two and one further building block, respectively. The latter could either be reconstructed from further perturbative data, or from BFKL integrals involving yet-unknown corrections to the central emission block, on whose construction we also briefly comment.

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Jul 2016; 21 p; ISSN 0418-9833;

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Gonzalez, Ivan; Kniehl, Bernd A.; Kondrashuk, Igor; Notte-Cuello, Eduardo A.; Parra-Ferrada, Ivan; Rojas-Medar, Marko A.

Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)2016

Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)2016

AbstractAbstract

[en] In this paper we proceed to study properties of Mellin-Barnes (MB) transforms of Usyukina-Davydychev (UD) functions. In our previous papers [Nuclear Physics B 870 (2013) 243], [Nuclear Physics B 876 (2013) 322] we showed that multi-fold Mellin-Barnes (MB) transforms of Usyukina-Davydychev (UD) functions may be reduced to two-fold MB transforms and that the higher-order UD functions were obtained in terms of a differential operator by applying it to a slightly modified first UD function. The result is valid in d=4 dimensions and its analog in d=4-2ε dimensions exits too [Theoretical and Mathematical Physics 177 (2013) 1515]. In [Nuclear Physics B 870 (2013) 243] the chain of recurrent relations for analytically regularized UD functions was obtained implicitly by comparing the left hand side and the right hand side of the diagrammatic relations between the diagrams with different loop orders. In turn, these diagrammatic relations were obtained due to the method of loop reductions for the triangle ladder diagrams proposed in 1983 by Belokurov and Usyukina. Here we reproduce these recurrent relations by calculating explicitly via Barnes lemmas the contour integrals produced by the left hand sides of the diagrammatic relations. In such a way we explicitly calculate a family of multi-fold contour integrals of certain ratios of Euler gamma functions. We make a conjecture that similar results for the contour integrals are valid for a wider family of smooth functions which includes the MB transforms of UD functions.

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Dec 2016; 8 p; ISSN 0418-9833;

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Huetten, M.; Deutsches Elektronen-Synchrotron; Univ. Grenoble-Alpes, CNRS/IN2P3; Combet, C.; Maurin, D.

Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)2017

Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)2017

AbstractAbstract

[en] Recent high-energy data from Fermi-LAT on the diffuse γ-ray background have been used to set among the best constraints on annihilating TeV cold dark matter candidates. In order to assess the robustness of these limits, we revisit and update the calculation of the isotropic extragalactic γ-ray intensity from dark matter annihilation. The emission from halos with masses≥10

^{10}M_{s}un provides a robust lower bound on the predicted intensity. The intensity including smaller halos whose properties are extrapolated from their higher mass counterparts is typically 5 times higher, and boost from subhalos yields an additional factor ∝1.5. We also rank the uncertainties from all ingredients and provide a detailed error budget for them. Overall, our fiducial intensity is a factor 5 lower than the one derived by the Fermi-LAT collaboration in their latest analysis. This indicates that the limits set on extragalactic dark matter annihilations could be relaxed by the same factor. We also calculate the expected intensity for self-interacting dark matter in massive halos and find the emission reduced by a factor 3 compared to the collisionless counterpart. The next release of the CLUMPY code will provide all the tools necessary to reproduce and ease future improvements of this prediction.Primary Subject

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Nov 2017; 34 p; ISSN 0418-9833;

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ABSORPTION, ANNIHILATION, COSMIC PHOTONS, COSMIC RAY PROPAGATION, COSMIC X-RAY SOURCES, ENERGY SPECTRA, EXTRAPOLATION, GAMMA SPECTRA, GEV RANGE 01-10, GEV RANGE 10-100, INTERGALACTIC SPACE, MEV RANGE 100-1000, NONLUMINOUS MATTER, PHOTON EMISSION, POSTULATED PARTICLES, REACTION KINETICS, RED SHIFT, REST MASS

BOSONS, COSMIC RADIATION, COSMIC RAY SOURCES, ELEMENTARY PARTICLES, EMISSION, ENERGY RANGE, GEV RANGE, INTERACTIONS, IONIZING RADIATIONS, KINETICS, MASS, MASSLESS PARTICLES, MATHEMATICAL SOLUTIONS, MATTER, MEV RANGE, NUMERICAL SOLUTION, PARTICLE INTERACTIONS, PHOTONS, RADIATIONS, SORPTION, SPACE, SPECTRA

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