Results for "Joachim Kopp"

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Flavor Violation in the Scalar SectorMay 10 2016In many extensions of the Standard Model, the alignment in flavor space of the fermion mass matrices and the Yukawa coupling matrices can be broken. The physical scalar boson $h(125)$ could then have flavor changing couplings. In this talk, we summarize ... More
Constraints on dark matter annihilation from AMS-02 resultsApr 03 2013Oct 30 2013We use recently released data on the positron-to-electron ratio in cosmic rays from the AMS-02 experiment to constrain dark matter annihilation in the Milky Way. Due to the yet unexplained positron excess, limits are generally weaker than those obtained ... More
Production of keV Sterile Neutrinos in Supernovae: New Constraints and Gamma Ray ObservablesMay 02 2016Mar 03 2019We study the production of sterile neutrinos in supernovae, focusing in particular on the keV--MeV mass range, which is the most interesting range if sterile neutrinos are to account for the dark matter in the Universe. Focusing on the simplest scenario ... More
Decoherence by wave packet separation and collective neutrino oscillationsMay 28 2014Mar 01 2017In dense neutrino backgrounds present in supernovae and in the early Universe, neutrino oscillations may exhibit complex collective phenomena, such as synchronized oscillations, bipolar oscillations and spectral splits and swaps. In this Letter we consider ... More
New signals in dark matter detectorsOct 09 2012We investigate the scattering of solar neutrinos on electrons and nuclei in dark matter direct detection experiments. The rates of these processes are small in the Standard Model, but can be enhanced by several orders of magnitude if the neutrino sector ... More
Collider limits on dark matterMay 17 2011Dark matter pair production at high energy colliders may leave observable signatures in the energy and momentum spectra of the objects recoiling against the dark matter. We discuss signatures of Dark Matter in the jets + missing energy and photon + missing ... More
Mossbauer neutrinos in quantum mechanics and quantum field theoryApr 28 2009Jun 12 2009We demonstrate the correspondence between quantum mechanical and quantum field theoretical descriptions of Mossbauer neutrino oscillations. First, we compute the combined rate $\Gamma$ of Mossbauer neutrino emission, propagation, and detection in quantum ... More
New Signatures of Flavor Violating Higgs CouplingsJan 11 2016Jul 25 2016We explore several novel LHC signatures arising from quark or lepton flavor violating couplings in the Higgs sector, and we constrain such couplings using LHC data. Since the largest signals are possible in channels involving top quarks or tau leptons, ... More
Lepton Jets from Radiating Dark MatterMay 27 2015Jul 13 2015The idea that dark matter forms part of a larger dark sector is very intriguing, given the high degree of complexity of the visible sector. In this paper, we discuss lepton jets as a promising signature of an extended dark sector. As a simple toy model, ... More
Sterile Neutrino Oscillations: The Global PictureMar 12 2013Mar 27 2014Neutrino oscillations involving eV-scale neutrino mass states are investigated in the context of global neutrino oscillation data including short and long-baseline accelerator, reactor, and radioactive source experiments, as well as atmospheric and solar ... More
From gamma ray line signals of dark matter to the LHCJan 08 2013Aug 18 2013We explore the relationship between astrophysical gamma-ray signals and LHC signatures for a class of phenomenologically successful secluded dark matter models, motivated by recent evidence for a ~130 GeV gamma-ray line. We consider in detail scenarios ... More
Efficient numerical diagonalization of hermitian 3x3 matricesOct 24 2006Jul 04 2008A very common problem in science is the numerical diagonalization of symmetric or hermitian 3x3 matrices. Since standard "black box" packages may be too inefficient if the number of matrices is large, we study several alternatives. We consider optimized ... More
LEP Shines Light on Dark MatterMar 01 2011Dark matter pair production at high energy colliders may leave observable signatures in the energy and momentum spectra of the objects recoiling against the dark matter. We use LEP data on mono-photon events with large missing energy to constrain the ... More
Two experiments for the price of one? -- The role of the second oscillation maximum in long baseline neutrino experimentsOct 18 2010May 09 2011We investigate the quantitative impact that data from the second oscillation maximum has on the performance of wide band beam neutrino oscillation experiments. We present results for the physics sensitivities to standard three flavor oscillation, as well ... More
Testing the wave packet approach to neutrino oscillations in future experimentsMay 21 2010Nov 25 2010When neutrinos propagate over long distances, the mass eigenstate components of a flavor eigenstate will become spatially separated due to their different group velocities. This can happen over terrestrial distance scales if the neutrino energy is of ... More
A ménage à trois of eV-scale sterile neutrinos, cosmology, and structure formationOct 23 2013Jun 13 2014We show that sterile neutrinos with masses ~1 eV or larger, as motivated by several short-baseline oscillation anomalies, can be consistent with cosmological constraints if they are charged under a hidden sector force mediated by a light boson. In this ... More
Ultra-low Q values for neutrino mass measurementsNov 17 2009Apr 21 2010We investigate weak nuclear decays with extremely small kinetic energy release (Q value) and thus extremely good sensitivity to the absolute neutrino mass scale. In particular, we consider decays into excited daughter states, and we show that partial ... More
Detecting atmospheric neutrino oscillations in the ATLAS detector at CERNMay 17 2007Nov 16 2007We discuss the possibility to study oscillations of atmospheric neutrinos in the ATLAS experiment at CERN. Due to the large total detector mass, a significant number of events is expected, and during the shutdown phases of the LHC, reconstruction of these ... More
Flavor and CP violation in Higgs decaysJun 20 2014Flavor violating interactions of the Higgs boson are a generic feature of models with extended electroweak symmetry breaking sectors. Here, we investigate CP violation in these interactions, which can arise from interference of tree-level and 1-loop diagrams. ... More
The Not-So-Sterile 4th Neutrino: Constraints on New Gauge Interactions from Neutrino Oscillation ExperimentsAug 01 2014Sterile neutrino models with new gauge interactions in the sterile sector are phenomenologically interesting since they can lead to novel effects in neutrino oscillation experiments, in cosmology and in dark matter detectors, possibly even explaining ... More
The Vev Flip-Flop: Dark Matter Decay between Weak Scale Phase TransitionsAug 26 2016Oct 25 2016We propose a new alternative to the Weakly Interacting Massive Particle (WIMP) paradigm for dark matter. Rather than being determined by thermal freeze-out, the dark matter abundance in this scenario is set by dark matter decay, which is allowed for a ... More
The Vev Flip-Flop: Dark Matter Decay between Weak Scale Phase TransitionsAug 26 2016We propose a new alternative to the Weakly Interacting Massive Particle (WIMP) paradigm for dark matter. Rather than being determined by thermal freeze-out, the dark matter abundance in this scenario is set by dark matter decay, which is allowed for a ... More
Sterile neutrinos and indirect dark matter searches in IceCubeFeb 15 2012Jul 06 2012If light sterile neutrinos exist and mix with the active neutrino flavors, this mixing will affect the propagation of high-energy neutrinos from dark matter annihilation in the Sun. In particular, new Mikheyev-Smirnov-Wolfenstein resonances can occur, ... More
Neutrino oscillations: Quantum mechanics vs. quantum field theoryJan 27 2010Nov 20 2012A consistent description of neutrino oscillations requires either the quantum-mechanical (QM) wave packet approach or a quantum field theoretic (QFT) treatment. We compare these two approaches to neutrino oscillations and discuss the correspondence between ... More
The Vev Flip-Flop: Dark Matter Decay between Weak Scale Phase TransitionsAug 26 2016Mar 06 2017We propose a new alternative to the Weakly Interacting Massive Particle (WIMP) paradigm for dark matter. Rather than being determined by thermal freeze-out, the dark matter abundance in this scenario is set by dark matter decay, which is allowed for a ... More
Production of keV Sterile Neutrinos in Supernovae: New Constraints and Gamma Ray ObservablesMay 02 2016We study the production of sterile neutrinos in supernovae, focusing in particular on the keV--MeV mass range, which is the most interesting range if sterile neutrinos are to account for the dark matter in the Universe. We argue that in this mass range, ... More
Sterile Neutrinos with Secret Interactions - Lasting Friendship with CosmologyMay 11 2015Sterile neutrinos with mass ~1 eV and order 10% mixing with active neutrinos have been proposed as a solution to anomalies in neutrino oscillation data, but are tightly constrained by cosmological limits. It was recently shown that these constraints are ... More
Boosted Dark Matter in IceCube and at the Galactic CenterMar 09 2015May 21 2015We show that the event excess observed by the IceCube collaboration at TeV--PeV energies, usually interpreted as evidence for astrophysical neutrinos, can be explained alternatively by the scattering of highly boosted dark matter particles. Specifically, ... More
Sterile Neutrinos and Flavor Ratios in IceCubeNov 14 2016Jan 17 2017The flavor composition of astrophysical neutrinos observed in neutrino telescopes is a powerful discriminator between different astrophysical neutrino production mechanisms and can also teach us about the particle physics properties of neutrinos. In this ... More
Neutrino factory optimization for non-standard interactionsApr 15 2008We study the optimization of a neutrino factory with respect to non-standard neutral current neutrino interactions, and compare the results to those obtained without non-standard interactions. We discuss the muon energy, baselines, and oscillation channels ... More
Decoherence by wave packet separation and collective neutrino oscillationsMay 28 2014In dense neutrino backgrounds present in supernovae and in the early Universe, neutrino oscillations may exhibit complex collective phenomena, such as synchronized oscillations, bipolar oscillations and spectral splits and swaps. In this Letter we consider ... More
Light Dark Matter in the light of CRESST-IIOct 12 2011Recently the CRESST collaboration has published the long anticipated results of their direct Dark Matter (DM) detection experiment with a CaWO_4 target. The number of observed events exceeds known backgrounds at more than 4 sigma significance, and this ... More
Discovery reach for non-standard interactions in a neutrino factoryFeb 26 2007Jul 08 2007We study the discovery reach for Non-Standard Interactions (NSIs) in a neutrino factory experiment. After giving a theoretical, but model-independent, overview of the most relevant classes of NSIs, we present detailed numerical results for some of them. ... More
Sterile Neutrinos and Flavor Ratios in IceCubeNov 14 2016The flavor composition of astrophysical neutrinos observed in neutrino telescopes is a powerful discriminator between different astrophysical neutrino production mechanisms and can also teach us about the particle physics properties of neutrinos. In this ... More
Disentangling Flavor Violation in the Top-Higgs Sector at the LHCApr 04 2014Jul 16 2014We study the LHC phenomenology of flavor changing Yukawa couplings between top quark, Higgs boson, and either an up or charm quark. Such $tuh$ or $tch$ couplings arise for instance in models in which Higgs sector is extended by the existence of additional ... More
Neutrino Anarchy and Renormalization Group EvolutionNov 19 2015May 25 2016The observed pattern of neutrino mixing angles is in good agreement with the hypothesis of neutrino anarchy, which posits that Nature has chosen the entries of the leptonic mixing matrix at random. In this paper we investigate how stable this conclusion ... More
Are there sterile neutrinos at the eV scale?Mar 23 2011Mar 25 2011New predictions for the anti-neutrino flux emitted by nuclear reactors suggest that reactor experiments may have measured a deficit in the anti-neutrino flux, which can be interpreted in terms of oscillations between the known active neutrinos and new ... More
Global interpretation of direct Dark Matter searches after CDMS-II resultsDec 22 2009Mar 02 2010We perform a global fit to data from Dark Matter (DM) direct detection experiments, including the recent CDMS-II results. We discuss possible interpretations of the DAMA annual modulation signal in terms of spin-independent and spin-dependent DM-nucleus ... More
Comment on 'Time-energy uncertainty relations for neutrino oscillations and the Mossbauer neutrino experiment'Mar 10 2008May 01 2009We discuss the implications of the time-energy uncertainty relation to recoillessly emitted and captured neutrinos (Mossbauer neutrinos) and show that it does not preclude oscillations of these neutrinos, contrary to a recent claim (J. Phys. G35 (2008) ... More
Collective neutrino oscillations and neutrino wave packetsFeb 27 2017Sep 20 2017Effects of decoherence by wave packet separation on collective neutrino oscillations in dense neutrino gases are considered. We estimate the length of the wave packets of neutrinos produced in core collapse supernovae and the expected neutrino coherence ... More
Dark Gamma Ray BurstsJul 14 2016Apr 02 2017Many theories of dark matter (DM) predict that DM particles can be captured by stars via scattering on ordinary matter. They subsequently condense into a DM core close to the center of the star and eventually annihilate. In this work, we trace DM capture ... More
Antineutrino monitoring of spent nuclear fuelJun 20 2016Dec 22 2017Military and civilian applications of nuclear energy have left a significant amount of spent nuclear fuel over the past 70 years. Currently, in many countries world wide, the use of nuclear energy is on the rise. Therefore, the management of highly radioactive ... More
Photons, Photon Jets and Dark Photons at 750 GeV and BeyondFeb 15 2016Jun 13 2016In new physics searches involving photons at the LHC, one challenge is to distinguish scenarios with isolated photons from models leading to "photon jets". For instance, in the context of the 750 GeV diphoton excess, it was pointed out that a true diphoton ... More
Flavor Violating Higgs DecaysSep 06 2012Aug 14 2015We study a class of nonstandard interactions of the newly discovered 125 GeV Higgs-like resonance that are especially interesting probes of new physics: flavor violating Higgs couplings to leptons and quarks. These interaction can arise in many frameworks ... More
Antineutrino monitoring of spent nuclear fuelJun 20 2016Military and civilian applications of nuclear energy have left a significant amount of spent nuclear fuel over the past 70 years. Currently, in many countries world wide, the use of nuclear energy is on the rise. Therefore, the management of highly radioactive ... More
Dark Gamma Ray BurstsJul 14 2016Many theories of dark matter (DM) predict that DM particles can be captured by stars via scattering on ordinary matter. They subsequently condense into a DM core close to the center of the star and eventually annihilate. In this work, we trace DM capture ... More
Self-Calibration of Neutrino Detectors using characteristic BackgroundsMar 06 2007We introduce the possibility to use characteristic natural neutrino backgrounds, such as Geoneutrinos (\bar{\nu}_e) or solar neutrinos (\nu_e), with known spectral shape for the energy calibration of future neutrino detectors, e.g. Large Liquid Scintillator ... More
Oscillations of Mossbauer neutrinosFeb 18 2008May 02 2008We calculate the probability of recoilless emission and detection of neutrinos (Mossbauer effect with neutrinos) taking into account the boundedness of the parent and daughter nuclei in the neutrino source and detector as well as the leptonic mixing. ... More
Loopy Constraints on Leptophilic Dark Matter and Internal BremsstrahlungJan 24 2014Apr 25 2014A sharp and spatially extended peak in an astrophysical gamma ray spectrum would provide very strong evidence for the existence of dark matter (DM), given that there are no known astrophysical processes that could mimic such a signal. From the particle ... More
Systematic uncertainties in long-baseline neutrino oscillations for large $θ_{13}$Sep 26 2012We study the physics potential of future long-baseline neutrino oscillation experiments at large $\theta_{13}$, focusing especially on systematic uncertainties. We discuss superbeams, \bbeams, and neutrino factories, and for the first time compare these ... More
Impact of non-standard neutrino interactions on future oscillation experimentsOct 09 2007We study the performance of reactor and superbeam neutrino experiments in the presence of non-standard interactions (NSI). We find that for some non-standard terms, reactor and superbeam experiments would yield conflicting result in the theta-13 determination, ... More
Interpretation of MINOS data in terms of non-standard neutrino interactionsAug 31 2010The MINOS experiment at Fermilab has recently reported a tension between the oscillation results for neutrinos and anti-neutrinos. We show that this tension, if it persists, can be understood in the framework of non-standard neutrino interactions (NSI). ... More
Femtolensing by Dark Matter RevisitedJul 30 2018Nov 30 2018Femtolensing of gamma ray bursts (GRBs) has been put forward as an exciting possibility to probe exotic astrophysical objects with masses below $10^{-13}$ solar masses such as small primordial black holes or ultra-compact dark matter minihalos, made up ... More
Return of the X-rays: A New Hope for Fermionic Dark Matter at the keV ScaleOct 05 2017Feb 06 2018A long time ago (in 2014), in galaxies and galaxy clusters far, far away, several groups have reported hints for a yet unidentified line in astrophysical X-ray signals at an energy of 3.5\,keV. While it is not unlikely that this line is simply a reflection ... More
Dynamic Freeze-In: Impact of Thermal Masses and Cosmological Phase Transitions on Dark Matter ProductionDec 11 2017Mar 12 2018The cosmological abundance of dark matter can be significantly influenced by the temperature dependence of particle masses and vacuum expectation values. We illustrate this point in three simple freeze-in models. The first one, which we call kinematically ... More
Dark, Cold, and Noisy: Constraining Secluded Hidden Sectors with Gravitational WavesNov 27 2018We explore gravitational wave signals arising from first-order phase transitions occurring in a secluded hidden sector, allowing for the possibility that the hidden sector may have a different temperature than the Standard Model sector. We present the ... More
Random-Matrix Theory: Distribution of Mesoscopic Supercurrents through a Chaotic CavitySep 27 2001We investigate the distribution of the supercurrent through a chaotic quantum dot which is strongly coupled to two superconductors when the Thouless energy is large compared to the superconducting energy gap. The distribution function of the critical ... More
Is there a hot spot of sea-level rise acceleration along the mid-Atlantic United States? A Gaussian process decomposition of tide gauge recordsApr 19 2013Jul 17 2013To test a hypothesized faster-than-global sea-level acceleration along the mid-Atlantic United States, I construct a Gaussian process model that decomposes tide gauge data into short-term variability and longer-term trends, and into globally-coherent, ... More
Non-standard neutrino interactions in reactor and superbeam experimentsAug 01 2007Jan 29 2008The formalism of non-standard four-fermion interactions provides a convenient, model-independent way of parameterizing a wide class of ``new physics'' scenarios. In this article, we study the performance of reactor and superbeam neutrino experiments in ... More
Cuckoo's Eggs in Neutron Stars: Can LIGO Hear Chirps from the Dark Sector?Jul 06 2018Dec 07 2018We explore in detail the possibility that gravitational wave signals from binary inspirals are affected by a new force that couples only to dark matter particles. We discuss the impact of both the new force acting between the binary partners as well as ... More
Sterile Neutrinos with Secret Interactions -- Cosmological Discord?Jun 27 2018Several long-standing anomalies from short-baseline neutrino oscillation experiments -- most recently corroborated by new data from MiniBooNE -- have led to the hypothesis that extra, 'sterile', neutrino species might exist. Models of this type face severe ... More
A CoGeNT Modulation AnalysisJul 04 2011Mar 09 2012We analyze the recently released CoGeNT data with a focus on their time-dependent properties. Using various statistical techniques, we confirm the presence of modulation in the data, and find a significant component at high (E_{ee} > 1.5$ keVee) energies. ... More
Leptophilic Dark Matter in Direct Detection Experiments and in the SunNov 05 2010Dark matter interacting predominantly with leptons instead of nuclear matter has received a lot of interest recently. In this talk, we investigate the signals expected from such 'leptophilic Dark Matter' in direct detection experiments and in experiments ... More
On a theory of neutrino oscillations with entanglementJun 11 2010Nov 03 2010We show that, despite appearances, a theoretical approach to neutrino oscillation in which the neutrino and its interaction partners are entangled yields the standard result for the neutrino oscillation wavelength. We also shed some light on the question ... More
The GSI anomalyAug 18 2008Recently, an experiment at GSI Darmstadt has observed oscillating decay rates of heavy ions. Several controversial attempts have been made to explain this effect in terms of neutrino mixing. We briefly describe the experimental results, give an overview ... More
Missing Energy Signatures of Dark Matter at the LHCSep 20 2011Jun 09 2014We use ATLAS and CMS searches in the mono-jet + missing energy and mono-photon + missing energy final state to set limits on the couplings of dark matter to quarks and gluons. Working in an effective field theory framework we compare several existing ... More
Stellar Wakes from Dark Matter SubhalosNov 09 2017We propose a novel method utilizing stellar kinematic data to detect low-mass substructure in the Milky Way's dark matter halo. By probing characteristic wakes that a passing dark matter subhalo leaves in the phase space distribution of ambient halo stars, ... More
Light Z' Bosons at the TevatronMar 30 2011Oct 13 2011New gauge bosons with Standard Model-like couplings to leptons are constrained by collider searches to be heavier than approximately ~1 TeV. A Z' boson with suppressed couplings to leptons, however, could be much lighter and possess substantial couplings ... More
On the Consistency of Perturbativity and Gauge Coupling UnificationSep 14 2009We investigate constraints that the requirements of perturbativity and gauge coupling unification impose on extensions of the Standard Model and of the MSSM. In particular, we discuss the renormalization group running in several SUSY left-right symmetric ... More
Reactor Neutrino Experiments with a Large Liquid Scintillator DetectorJun 13 2006Jan 19 2007We discuss several new ideas for reactor neutrino oscillation experiments with a Large Liquid Scintillator Detector. We consider two different scenarios for a measurement of the small mixing angle $\theta_{13}$ with a mobile $\bar{\nu}_e$ source: a nuclear-powered ... More
Exploring nu signals in dark matter detectorsFeb 27 2012Aug 03 2015We investigate standard and non-standard solar neutrino signals in direct dark matter detection experiments. It is well known that even without new physics, scattering of solar neutrinos on nuclei or electrons is an irreducible background for direct dark ... More
DAMA/LIBRA and leptonically interacting Dark MatterJul 20 2009Oct 02 2009We consider the hypothesis that Dark Matter (DM) has tree-level interactions only with leptons. Such a framework, where DM recoils against electrons bound in atoms, has been proposed as an explanation for the annually modulated scintillation signal in ... More
New features in the simulation of neutrino oscillation experiments with GLoBES 3.0Jan 22 2007Aug 28 2007We present Version 3.0 of the GLoBES (``General Long Baseline Experiment Simulator'') software, which is a simulation tool for short- and long-baseline neutrino oscillation experiments. As a new feature, GLoBES 3.0 allows for user-defined systematical ... More
Symmetry Restored in Dibosons at the LHC?Jun 30 2015Nov 12 2015A number of LHC resonance search channels display an excess in the invariant mass region of 1.8 - 2.0 TeV. Among them is a $3.4\,\sigma$ excess in the fully hadronic decay of a pair of Standard Model electroweak gauge bosons, in addition to potential ... More
GPU-accelerated simulation of colloidal suspensions with direct hydrodynamic interactionsMay 29 2012Solvent-mediated hydrodynamic interactions between colloidal particles can significantly alter their dynamics. We discuss the implementation of Stokesian dynamics in leading approximation for streaming processors as provided by the compute unified device ... More
Fractal Weyl laws for quantum decay in generic dynamical systemsJun 29 2009Weyl's law approximates the number of states in a quantum system by partitioning the energetically accessible phase-space volume into Planck cells. Here we show that typical resonances in generic open quantum systems follow a modified, fractal Weyl law, ... More
Criticality in correlated quantum matterMar 11 2005Sep 30 2005At quantum critical points (QCP) \cite{Pfeuty:1971,Young:1975,Hertz:1976,Chakravarty:1989,Millis:1993,Chubukov:1 994,Coleman:2005} there are quantum fluctuations on all length scales, from microscopic to macroscopic lengths, which, remarkably, can be ... More
Magnetically ordered state at correlated oxide interfaces: the role of random oxygen defectsMay 09 2012Using an effective one-band Hubbard model with disorder, we consider magnetic states of the correlated oxide interfaces, where effective hole self-doping and a magnetially ordered state emerge due to electronic and ionic reconstructions. By employing ... More
Exact results with the Kotliar-Ruckenstein slave-boson representationMay 02 2012Radial slave boson representations have the particular advantage that the expectation values of their respective fields are finite even without the formal introduction of spurious Bose condensates for each of the bosonic fields. The expectation values ... More
Structural relaxation and metal-insulator transition at the interface between SrTiO3 and LaAlO3Jan 29 2009Feb 27 2010The electronic structure of interfaces between LaAlO$_3$ and SrTiO$_3$ is studied using local spin density approximation (LSDA) with intra-atomic Coulomb repulsion (LSDA+U). We find that the nature of the interface metallic states is strongly affected ... More
Interface controlled electronic charge inhomogeneities in correlated heterostructuresMar 23 2006Sep 17 2006For heterostructures of ultrathin, strongly correlated copper-oxide films and dielectric perovskite layers, we predict inhomogeneous electronic interface states. Our study is based on an extended Hubbard model for the cuprate film. The interface is implemented ... More
Radiation-condensation instability in a four-fluid dusty plasmaMay 18 2007In this work linear stability analysis of a four-fluid optically thin plasma consisting of electrons, ions, neutral atoms, and charged dust particles is performed with respect to the radiation-condensation (RC) instability. The energy budget of the plasma ... More
Impeded Dark MatterSep 07 2016Sep 11 2016We consider a new class of thermal dark matter models, dubbed "Impeded Dark Matter", in which the mass splitting between the dark matter particles and their annihilation products is tiny. Compared to the previously proposed Forbidden Dark Matter scenario, ... More
Fuzzy Dark Matter and Non-Standard Neutrino InteractionsMay 26 2017Feb 02 2018We discuss novel ways in which neutrino oscillation experiments can probe dark matter. In particular, we focus on interactions between neutrinos and ultra-light ("fuzzy") dark matter particles with masses of order $10^{-22}$ eV. It has been shown previously ... More
Sterile Neutrinos or Flux Uncertainties? - Status of the Reactor Anti-Neutrino AnomalySep 13 2017Nov 22 2017The $\sim 3\sigma$ discrepancy between the predicted and observed reactor anti-neutrino flux, known as the reactor anti-neutrino anomaly, continues to intrigue. The recent discovery of an unexpected bump in the reactor anti-neutrino spectrum, as well ... More
What the Tevatron Found?Jul 28 2011Oct 13 2011The CDF collaboration has reported a 4.1\sigma\ excess in their lepton, missing energy, and dijets channel. This excess, which takes the form of an approximately Gaussian peak centered at a dijet invariant mass of 147 GeV, has provoked a great deal of ... More
Impeded Dark MatterSep 07 2016Dec 14 2016We consider dark matter models in which the mass splitting between the dark matter particles and their annihilation products is tiny. Compared to the previously proposed Forbidden Dark Matter scenario, the mass splittings we consider are much smaller, ... More
Power laws in surface physics: The deep, the shallow and the usefulMar 10 2004The growth and dynamics of solid surfaces displays a multitude of power law relationships, which are often associated with geometric self-similarity. In many cases the mechanisms behind these power laws are comparatively trivial, and require little more ... More
New mechanism for impurity-induced step bunchingFeb 28 2002Jul 25 2002Codeposition of impurities during the growth of a vicinal surface leads to an impurity concentration gradient on the terraces, which induces corresponding gradients in the mobility and the chemical potential of the adatoms. Here it is shown that the two ... More
Records in a changing worldFeb 06 2007In the context of this paper, a record is an entry in a sequence of random variables (RV's) that is larger or smaller than all previous entries. After a brief review of the classic theory of records, which is largely restricted to sequences of independent ... More
Sequence-specific size, structure, and stability of tight protein knotsSep 04 2008Approximately 1% of the known protein structures display knotted configurations in their native fold but their function is not understood. It has been speculated that the entanglement may inhibit mechanical protein unfolding or transport, e.g., as in ... More
Bivariant $K$-theory and the Weyl algebraJan 22 2004Jul 19 2004We introduce a new version $kk^{\rm alg}$ of bivariant $K$-theory that is defined on the category of all locally convex algebras. A motivating example is the Weyl algebra $W$, i.e. the algebra generated by two elements satisfying the Heisenberg commutation ... More
Evolutionary Model of the Personal Income DistributionMar 29 2012The aim of this work is to establish the personal income distribution from the elementary constituents of a free market; products of a representative good and agents forming the economic network. The economy is treated as a self-organized system. Based ... More
Graphs, hypergraphs, and properadsJul 14 2014Apr 03 2015A categorical formalism for directed graphs is introduced, featuring natural notions of morphisms and subgraphs, and leading to two elementary descriptions of the free-properad monad, first in terms of presheaves on elementary graphs, second in terms ... More
VSPs of cubic fourfolds and the Gorenstein locus of the Hilbert scheme of 14 points on A^6Nov 14 2016Apr 27 2018This paper is concerned with the geometry of the Gorenstein locus of the Hilbert scheme of $14$ points on $\mathbb{A}^6$. This scheme has two components: the smoothable one and an exceptional one. We prove that the latter is smooth and identify the intersection ... More
On pairs of interacting electrons in a quantum wireJan 02 2018In this paper we consider pairs of interacting electrons moving in a simple quantum wire, namely the half-line. In particular, we extend the results obtained in [arXiv:1708.03753] by allowing for contact interactions of the Lieb-Liniger type between the ... More
On the impact of surface defects on a condensate of electron pairs in a quantum wireDec 20 2017Jun 18 2018In this paper we are interested in understanding the impact of surface defects on a condensate of electron pairs in a quantum wire. Based on previous results we establish a simple mathematical model in order to account for such surface effects. For a ... More
Free Choice Petri Nets without frozen tokens and Bipolar Synchronization SystemsSep 17 2006Sep 10 2007Bipolar synchronization systems (BP-systems) constitute a class of coloured Petri nets, well suited for modeling the control flow of discrete, dynamical systems. Every BP-system has an underlying ordinary Petri net, which is a T-system. Moreover, it has ... More
Comment on "Dynamic Scaling of Non-Euclidean Interfaces" [arXiv:0804.1898]Oct 27 2008Feb 23 2009This is the revised version of a Comment on a paper by C. Escudero (Phys. Rev. Lett. 100, 116101, 2008; arXiv:0804.1898).
Lonely adatoms in spaceFeb 14 2003There is a close relation between the problems of second layer nucleation in epitaxial crystal growth and chemical surface reactions, such as hydrogen recombination, on interstellar dust grains. In both cases standard rate equation analysis has been found ... More