Results for "Jens Kling"
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Heavy Neutral Leptons at FASERJan 26 2018We study the prospects for discovering heavy neutral leptons at ForwArd Search ExpeRiment, or FASER, the newly proposed detector at the LHC. Previous studies showed that a relatively small detector with ~10 m length and ~1 m cross sectional area can probe ... More Constraining Type II 2HDM in Light of LHC Higgs SearchesApr 30 2013Mar 14 2014We study the implication of the LHC Higgs search results on the Type II Two Higgs-Doublet Model. In particular, we explore the scenarios in which the observed 126 GeV Higgs signal is interpreted as either the light CP-even Higgs $h^0$ or the heavy CP-even ... More Superstring BRST CohomologyApr 11 2001Jul 12 2001We first derive all world-sheet action functionals for NSR superstring models with (1,1) supersymmetry and any number of abelian gauge fields, for gauge transformations of the standard form. Then we prove for these models that the BRST cohomology groups ... More SU(2) WZW D-branes and quantized worldvolume U(1) flux on S^2May 16 2000May 22 2000We discuss possible D-brane configurations on SU(2) group manifolds in the sigma model approach. When we turn the boundary conditions of the spacetime fields into the boundary gluing conditions of chiral currents, we find that for all D-branes except ... More M-brane singularity formationDec 09 2008We derive self-similar string solutions in a graph representation, near the point of singularity formation, which can be shown to extend to point-like singularities on M-branes, as well as to the radially symmetric case. Fermat Potentials for Non-Perturbative Gravitational LensingMay 03 2002The images of many distant galaxies are displaced, distorted and often multiplied by the presence of foreground massive galaxies near the line of sight; the foreground galaxies act as gravitational lenses. Commonly, the lens equation, which relates the ... More Chromatic weight systems and the corresponding knot invariantsJan 13 1997This paper contains a proof that chromatic weight systems, introduced by Chmutov, Duzhin and Lando, can be expressed in terms of weight systems associated with direct sums of the Lie algebras gl_n and so_n. As a consequence the Vassiliev invariants of ... More Anomaly Cancellation in Six DimensionsApr 22 1993I show that anomaly cancellation conditions are sufficient to determine the two most important topological numbers relevant for Calabi-Yau compactification to six dimensions. This reflects the fact that K3 is the only non-trivial CY manifold in two complex ... More Breakdown of Duality in (0,2) Superstring ModelsJun 16 1993After pointing out the role of the compactification lattice for spectrum calculations in orbifold models, I discuss modular discrete symmetry groups for $Z_N$ or\-bi\-folds. I consider the $Z_7$ orbifold as a nontrivial example of a (2,2) model and give ... More Block-diagonalisation of matrices and operatorsOct 14 2008In this short note we deal with a constructive scheme to decompose a continuous family of matrices $A(\rho)$ asymptotically as $\rho\to0$ into blocks corresponding to groups of eigenvalues of the limit matrix A(0). We also discuss the extension of the ... More Selberg's trace formula: an introductionJul 16 2004Feb 13 2008These lecture notes provide a basic introduction to Selberg's trace formula. We discuss the simplest possible case: the spectrum of the Laplacian on a compact Riemannian surface of constant negative curvature. (To appear in Springer LNP.) Quantum LeaksMar 28 2005We show that eigenfunctions of the Laplacian on certain non-compact domains with finite area may localize at infinity--provided there is no extreme level clustering--and thus rule out quantum unique ergodicity for such systems. The construction is elementary ... More U(1) invariant Membranes and SingularitiesMay 30 2008A formulation of U(1) - symmetric classical membrane motions (preserving one rotational symmetry) is given, and reductions to systems of ODE's, as well as some ideas concerning singularities and integrability. M-brane dynamical symmetry and quantizationJan 22 2011The recently discovered dynamical symmetry for relativistic extended objects is derived from first principles, and analogues commutators are obtained for the corresponding formal quantum expressions Dynamics of nanojetsJan 02 2002We study the breakup of a liquid jet a few nanometers in diameter, based on a stochastic differential equation derived recently by Moseler and Landman [Science {\bf 289}, 1165 (2000)]. In agreement with their simulations, we confirm that noise qualitatively ... More Hydrodynamic theory of de-wettingDec 24 2003A prototypical problem in the study of wetting phenomena is that of a solid plunging into or being withdrawn from a liquid bath. In the latter, de-wetting case, a critical speed exists above which a stationary contact line is no longer sustainable and ... More Which spectral distortions does $Λ$CDM actually predict?Mar 08 2016May 20 2016Ever refined cosmological measurements have established the $\Lambda$CDM concordance model, with the key cosmological parameters being determined to percent-level precision today. This allows us to make explicit predictions for the spectral distortions ... More Tropical multiplier sequencesMay 23 2015We prove that the diagonal operator defined by a positive sequence preserves tropical and central indices if and only if the sequence is log-concave. In particular we obtain an elementary proof of that such an operator preserves the set of sign-independently ... More Designs and codes in affine geometryMay 12 2016May 23 2016Classical designs and their (projective) q-analogs can both be viewed as designs in matroids, using the matroid of all subsets of a set and the matroid of linearly independent subsets of a vector space, respectively. Another natural matroid is given by ... More On harmonic and asymptotically harmonic homogeneous spacesSep 20 2004Oct 04 2005We classify noncompact homogeneous spaces which are Einstein and asymptotically harmonic. This completes the classification of Riemannian harmonic spaces in the homogeneous case: Any simply connected homogeneous harmonic space is flat, or rank-one symmetric, ... More On modular semifinite index theoryNov 28 2011We propose a definition of a modular spectral triple which covers existing examples arising from KMS-states, Podles sphere and quantum SU(2). The definition also incorporates the notion of twisted commutators appearing in recent work of Connes and Moscovici. ... More Invariant Differential PairingsMar 29 2007Apr 12 2008In this paper the notion of an M-th order invariant bilinear differential pairing is introduced and a formal definition is given. If the manifold has an AHS structure, then various first order pairings are constructed. This yields a classification of ... More Pair correlation densities of inhomogeneous quadratic formsOct 14 2002Apr 20 2004Under explicit diophantine conditions on $(\alpha,\beta)\in\RR^2$, we prove that the local two-point correlations of the sequence given by the values $(m-\alpha)^2+\break (n-\beta)^2$, with $(m,n)\in\ZZ^2$, are those of a Poisson process. This partly ... More Fit to Electroweak Precision DataJun 12 2006A brief review of electroweak precision data from LEP, SLC, the Tevatron, and low energies is presented. The global fit to all data including the most recent results on the masses of the top quark and the W boson reinforces the preference for a relatively ... More The Probability Density of the Higgs Boson MassOct 15 2000Jan 11 2001The LEP Collaborations have reported a small excess of events in their combined Higgs boson analysis at center of mass energies up to about 208 GeV. In this communication, I present the result of a calculation of the probability distribution function ... More Alpha_s with GAPPFeb 27 2011Details are provided how GAPP evaluates the strong coupling constant from Z and tau decays and the corresponding uncertainties. Radiative Corrections and Z'Sep 29 2009Radiative corrections to parity violating deep inelastic electron scattering are reviewed including a discussion of the renormalization group evolution of the weak mixing angle. Recently obtained results on hypothetical Z' bosons - for which parity violating ... More Electroweak Precision Data and New Gauge BosonsJul 05 2009I review constraints on the Standard Model (SM) Higgs boson from high energy electroweak (EW) precision data. The same data set also strongly limits various mixing effects of hypothetical extra neutral gauge bosons (Z') with the ordinary Z. I also discuss ... More Electroweak Radiative Corrections to Semileptonic Tau DecaysNov 22 2002Nov 25 2002I present an update on the electroweak radiative correction factor to semileptonic tau decays, including a next-to-leading order resummation of large logarithms. My result differs both qualitatively and quantitatively from the one recently obtained by ... More Chiral Models of Weak Scale SupersymmetryJun 05 2000I discuss supersymmetric extensions of the Standard Model containing an extra U(1)' gauge symmetry which provide a solution to the mu-problem and at the same time protect the proton from decaying via dimension 4 operators. Moreover, all fields are protected ... More Asymmetric Orbifolds and Higher Level ModelsFeb 07 1996Nov 29 1996I introduce a class of string constructions based on asymmetric orbifolds leading to level two models. In particular, I derive in detail various models with gauge groups $E_6$ and SO(10), including a four generation $E_6$ model with two adjoint representations. ... More The SLD Asymmetry in View of the LEP ResultsJun 30 1994LEP determines $\sin^2 \theta_{\rm eff}$, by combining the various asymmetry measurements to be $0.2321 \pm 0.0005$. On the other hand, the left-right asymmetry as measured at SLC corresponds to \seff = $0.2292 \pm 0.0010$. I will discuss the possibilities ... More Surface Motions and Fluid DynamicsMay 02 1994Jul 20 1994A certain class of surface motions, including those of a relativistic membrane minimizing the 3-dimensional volume swept out in Minkowski-space, is shown to be equivalent to 3-dimensional steady-state irrotational inviscid isentropic gas-dynamics. The ... More Autotools for writing portable softwareOct 20 2002Nov 01 2002Most of the scientific software is developed in the same manner: It starts at a lab and the scientist says "This part of software is only for my private use". But the software grows and grows, and it comes the time, that other scientists want to use it, ... More Instability of a moving contact lineJan 18 2005We study a solid plate plunging into or being withdrawn from a liquid bath, to highlight the fundamental difference between the local behavior of an advancing or a receding contact line, respectively. It is assumed that the liquid partially wets the solid, ... More Recursive Sorting in LatticesMay 31 2013The direct application of the definition of sorting in lattices is impractical because it leads to an algorithm with exponential complexity. In this paper we present for distributive lattices a recursive formulation to compute the sort of a sequence. ... More Reassembling trees for the traveling salesmanFeb 12 2015Jan 05 2016Many recent approximation algorithms for different variants of the traveling salesman problem (asymmetric TSP, graph TSP, s-t-path TSP) exploit the well-known fact that a solution of the natural linear programming relaxation can be written as convex combination ... More Kinetic limits of dynamical systemsAug 06 2014Since the pioneering work of Maxwell and Boltzmann in the 1860s and 1870s, a major challenge in mathematical physics has been the derivation of macroscopic evolution equations from the fundamental microscopic laws of classical or quantum mechanics. Macroscopic ... More The supernova/gamma-ray burst/jet connectionApr 29 2013The observed association between supernovae and gamma-ray bursts represents a cornerstone in our understanding of the nature of gamma-ray bursts. The collapsar model provides a theoretical framework for this connection. A key element is the launch of ... More Weighing in on the HiggsJan 03 2012Sep 13 2012Assuming the validity of the Standard Model, or more generally that possible physics beyond it would have only small effects on production cross sections, branching ratios and electroweak radiative corrections, I determine the mass of the Higgs boson ... More Dipolar-broadening of I=1/2-NMR spectra of solidsJan 11 1995Jan 13 1995The equations of motion of dipolar-coupled spins of I=1/2 placed on a rigid lattice are solved approximately in the high-temperature and high-field limit. The NMR-spectra predicted by this theory are in close agreement with both the theoretical spectral ... More Limitations of Skeptical Default ReasoningFeb 06 2013Poole has shown that nonmonotonic logics do not handle the lottery paradox correctly. In this paper we will show that Pollock's theory of defeasible reasoning fails for the same reason: defeasible reasoning is incompatible with the skeptical notion of ... More Horospheres and Farey fractionsMar 24 2010Mar 30 2010We embed multidimensional Farey fractions in large horospheres and explain under which conditions they become uniformly distributed in the ambient homogeneous space. This question has recently been investigated in the case of SL(d,Z) to prove the asymptotic ... More Modified scattering for a wave equation with weak dissipationSep 10 2005We consider the Cauchy problem for the weakly dissipative wave equation $$ \square u+\frac\mu{1+t} u_t=0 $$ with parameter $\mu\ge2$. Based on the explicit representations of solutions provided in [Math. Meth. Appl. Sci. 2004; {\bf 27}:101-124] sharp ... More Pair correlation densities of inhomogeneous quadratic forms IIOct 14 2002Denote by $\| \cdot \|$ the euclidean norm in $\RR^k$. We prove that the local pair correlation density of the sequence $\| \vecm -\vecalf \|^k$, $\vecm\in\ZZ^k$, is that of a Poisson process, under diophantine conditions on the fixed vector $\vecalf\in\RR^k$: ... More On Vassiliev Invariants not Coming from Semisimple Lie AlgebrasJun 04 1997Feb 05 2000We prove a refinement of Vogel's statement that the Vassiliev invariants of knots coming from semisimple Lie algebras do not generate all Vassiliev invariants. This refinement takes into account the second grading on Vassiliev invariants induced by cabling ... More Electroweak Standard Model and Precision TestsDec 18 2002Dec 29 2002I give an introduction and overview of recent developments in high precision tests of the Standard Model. This includes a summary of Z-pole measurements, a brief account of the NuTeV result on neutrino-nucleon scattering, the anomalous magnetic moment ... More The Mass of the Higgs Boson in the Standard Electroweak ModelFeb 05 2010Mar 16 2010An updated global analysis within the Standard Model (SM) of all relevant electroweak precision and Higgs boson search data is presented with special emphasis on the implications for the Higgs boson mass, M_H. Included are, in particular, the most recent ... More Spin beyond Standard Model: TheoryJan 29 2009Mar 11 2009I use spin as a guide through the labyrinth of possibilities and ideas that go beyond the established understanding of the fundamental interactions. Electroweak Theory for the Tevatron, LHC, and ILCSep 13 2008Oct 13 2008Future high precision electroweak measurements require understanding of Standard Model expectations to multi-loop accuracy, both, for the predictions of production cross-sections of signal and background, as well as for pseudo-observables. I review recent ... More Precision Electroweak PhysicsApr 04 2006The status in electroweak precision physics is reviewed. I present a brief summary of the latest data, global fit results, a few implications for new physics, and an outlook. Determinations of alpha(M_Z): Comparison and ProspectsOct 31 2001I review and compare various techniques to obtain the value of the QED coupling, alpha, at the Z pole. GigaZ precisions would require a much more accurate determination than available today. A combination of the virtues of current methods may help to ... More A calculation of the multiplicative characterMar 20 2009We give a formula, in terms of products of commutators, for the application of the odd multiplicative character to higher Loday symbols. On our way we construct a product on the relative K-groups and investigate the multiplicative properties of the relative ... More Quantum Group Generators in Conformal Field TheoryMar 12 1997These are notes of a seminar given at the 30th International Symposium on the Theory of Elementary Particles, Berlin-Buckow, August 1996. The material is derived from collaborations with E. Cremmer and J.-L. Gervais, and C. Klimcik, and is partially new. ... More Distribution modulo one and Ratner's theoremJun 09 2006Measure rigidity is a branch of ergodic theory that has recently contributed to the solution of some fundamental problems in number theory and mathematical physics. Examples are proofs of quantitative versions of the Oppenheim conjecture, related questions ... More Membranes and Matrix ModelsJun 20 2002Section I contains introductory remarks about surface motions. Section II gives a detailed derivation of $H=-\Delta-Tr\sum_{i<j}[X_i,X_j]^2$ as describing a quantized discrete analogue of relativistically invariant membrane dynamics. Section III concerns ... More Canonical 3+1 Description of Relativistic MembranesJul 18 1994Jul 20 1994$M$-dimensional extended objects $\Sigma$ can be described by projecting a Diff $\Sigma$ invariant Hamiltonian of time-independent Hamiltonian density {\cal H} onto the Diff $\Sigma$- singlet sector, which after Hamiltonian reduction, using {\cal H} itself ... More openDaVE - a data visualisation and transformation frameworkOct 20 2002At present each neutron scattering facility has its own set of data treatment software, normally based on a proprietary data format. The travelling scientist is either forced to continually learn new software or to write conversion routines for his own ... More Contact line motion for partially wetting fluidsOct 07 2005We study the flow close to an advancing contact line in the limit of small capillary number. To take into account wetting effects, both long and short-ranged contributions to the disjoining pressure are taken into account. In front of the contact line, ... More A brief history of drop formationMar 09 2004Surface-tension-related phenomena have fascinated researchers for a long time, and the mathematical description pioneered by Young and Laplace opened the door to their systematic study. The time scale on which surface-tension-driven motion takes place ... More Joint torsion of several commuting operatorsNov 01 2010Nov 28 2010We introduce the notion of joint torsion for several commuting operators satisfying a Fredholm condition. This new secondary invariant takes values in the group of invertibles of a field. It is constructed by comparing determinants associated with different ... More Methods for Higgs boson production at N$^3$LOOct 08 2015Oct 09 2015We discuss methods for the calculation of the total partonic Higgs boson production cross section via gluon fusion and the result for the contribution that stems from two quarks of different flavor in the initial state. Our calculation is exact in the ... More