TY  - JOUR
A1  - Hirsch, Martin
A1  - Krauss, Manuel E.
A1  - Opferkuch, Toby
A1  - Porod, Werner
A1  - Staub, Florian
T1  - A constrained supersymmetric left-right model
JF  - JOURNAL OF HIGH ENERGY PHYSICS
N2  - We present a supersymmetric left-right model which predicts gauge coupling unification close to the string scale and extra vector bosons at the TeV scale. The subtleties in constructing a model which is in agreement with the measured quark masses and mixing for such a low left-right breaking scale are discussed. It is shown that in the constrained version of this model radiative breaking of the gauge symmetries is possible and a SM-like Higgs is obtained. Additional CP-even scalars of a similar mass or even much lighter are possible. The expected mass hierarchies for the supersymmetric states differ clearly from those of the constrained MSSM. In particular, the lightest down-type squark, which is a mixture of the sbottom and extra vector-like states, is always lighter than the stop. We also comment on the model’s capability to explain current anomalies observed at the LHC.
KW  - supersymmetry
KW  - phenomenology
KW  - LHC
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-168016
VL  - 03
IS  - 009
ER  - 
TY  - THES
A1  - Schulz, Robert Frank
T1  - A radio view of high-energy emitting AGNs
T1  - Eine radioastronomische Betrachtung von hochenergetisch emittierenden AGNs
N2  - The most energetic versions of active galactic nuclei (AGNs) feature two highly-relativistic plasma outflows, so-called jets, that are created in the vicinity of the central supermassive black hole and evolve in opposite directions. In blazars, which dominate the extragalactic gamma-ray sky, the jets are aligned close to the observer's line of sight leading to strong relativistic beaming effects of the jet emission. Radio observations especially using very long baseline interferometry (VLBI) provide the best way to gain direct information on the intrinsic properties of jets down to sub-parsec scales, close to their formation region.
In this thesis, I focus on the properties of three AGNs, IC 310, PKS 2004-447, and 3C 111 that belong to the small non-blazar population of gamma-ray-loud AGNs. In these kinds of AGNs, the jets are less strongly aligned with respect to the observer than in blazars. I study them in detail with a variety of radio astronomical instruments with respect to their high-energy emission and in the context of the large samples in the monitoring programmes MOJAVE and TANAMI. My analysis of radio interferometric observations and flux density monitoring data reveal very different characteristics of the jet emission in these sources. The work presented in this thesis illustrates the diversity of the radio properties of gamma-ray-loud AGNs that do not belong to the dominating class of blazars.
N2  - Die energetischsten Versionen von aktiven Galaxienkernen (AGNs) weisen zwei hoch-relativistische Plasmaausflüsse, sogenannte Jets auf, welche in der Nähe des zentralen supermassiven schwarzen Lochs entstehen und sich in entgegengesetzte Richtungen ausbreiten. In Blazaren, die die extragalaktische Gamma-Strahlung dominieren, sind diese Jets nahe zur Sichtlinie des Beobachters orientiert, das zu starkem relativistischen Beaming der Jetemission führt. Radiobeobachtungen vor allem mit Very Long Baseline Interferometry (VLBI) bieten die beste Möglichkeit direkt Informationen über die intrinsischen Eigenschaften von Jets in der Nähe ihrer Entstehungsregion auf sub-parsec Skalen zu sammeln.
Der Fokus dieser Dissertation liegt auf den Eigenschaften von drei AGNs, IC 310, PKS 2004-447, and 3C 111, die zur kleinen Population von gamma-lauten AGNs abseits von Blazaren gehören. Diese Jets weisen einen etwas größeren Winkel zur Sichtlinie des Beobachters auf als Blazare. Ich untersuche diese AGNs im Detail mit Hilfe verschiedener radioastronomischer Instrumente in Bezug auf deren hochenergetischer Emission und im Vergleich der großen Samples der Langzeitbeobachtungsprogramme MOJAVE und TANAMI. Meine Analyse von Radiointerferometrie-Beobachtungen und Flussdichte-Messungen zeigen sehr unterschiedliche Eigenschaften der Jets. Damit verdeutlicht diese Arbeit anschaulich die vielfältigen Radioeigenschaften von gamma-lauten AGNs, die nicht zur dominierenden Klasse von Blazaren gehören.
KW  - Aktiver galaktischer Kern
KW  - Radioastronomie
KW  - Very long baseline interferometry
KW  - High-energy emission
KW  - Astrophysical Jet
KW  - Active galactic nucleus
KW  - Radio astronomy
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-137358
ER  - 
TY  - JOUR
A1  - Adrián-Martínez, S.
A1  - Albert, A.
A1  - André, M.
A1  - Anton, G.
A1  - Ardid, M.
A1  - Aubert, J.-J.
A1  - Avgitas, T.
A1  - Baret, B.
A1  - Barrios-Martí, J.
A1  - Basa, S.
A1  - Bertin, V.
A1  - Biagi, S.
A1  - Bormuth, R.
A1  - Bou-Cabo, M.
A1  - Bouwhuis, M.C.
A1  - Bruijn, R.
A1  - Brunner, J.
A1  - Busto, J.
A1  - Capone, A.
A1  - Caramete, L.
A1  - Carr, J.
A1  - Celli, S.
A1  - Chiarusi, T.
A1  - Circella, M.
A1  - Coleiro, A.
A1  - Coniglione, R.
A1  - Costantini, H.
A1  - Coyle, P.
A1  - Creusot, A.
A1  - Deschamps, A.
A1  - De Bonis, G.
A1  - Distefano, C.
A1  - Donzaud, C.
A1  - Dornic, D.
A1  - Drouhin, D.
A1  - Eberl, T.
A1  - El Bojaddaini, I.
A1  - Elsässer, D.
A1  - Enzenhöfer, A.
A1  - Fehn, K.
A1  - Felis, I.
A1  - Fusco, L.A.
A1  - Galatà, S.
A1  - Gay, P.
A1  - Geißelsöder, S.
A1  - Geyer, K.
A1  - Giordano, V.
A1  - Gleixner, A.
A1  - Glotin, H.
A1  - Gracia-Ruiz, R.
A1  - Graf, K.
A1  - Hallmann, S.
A1  - van Haren, H.
A1  - Heijboer, A.J.
A1  - Hello, Y.
A1  - Hernández-Rey, J.-J.
A1  - Hößl, J.
A1  - Hofestädt, J.
A1  - Hugon, C.
A1  - Illuminati, G.
A1  - James, C.W.
A1  - de Jong, M.
A1  - Kadler, M.
A1  - Kalekin, O.
A1  - Katz, U.
A1  - Kießling, D.
A1  - Kouchner, A.
A1  - Kreter, M.
A1  - Kreykenbohm, I.
A1  - Kulikovskiy, V.
A1  - Lachaud, C.
A1  - Lahmann, R.
A1  - Lefèvre, D.
A1  - Leonora, E.
A1  - Loucatos, S.
A1  - Marcelin, M.
A1  - Margiotta, A.
A1  - Marinelli, A.
A1  - Martínez-Mora, J.A.
A1  - Mathieu, A.
A1  - Michael, T.
A1  - Migliozzi, P.
A1  - Moussa, A.
A1  - Mueller, C.
A1  - Nezri, E.
A1  - Păvălaș, G.E.
A1  - Pellegrino, C.
A1  - Perrina, C.
A1  - Piattelli, P.
A1  - Popa, V.
A1  - Pradier, T.
A1  - Racca, C.
A1  - Riccobene, G.
A1  - Roensch, K.
A1  - Saldaña, M.
A1  - Samtleben, D.F.E.
A1  - Sanguineti, M.
A1  - Sapienza, P.
A1  - Schnabel, J.
A1  - Schüssler, F.
A1  - Seitz, T.
A1  - Sieger, C.
A1  - Spurio, M.
A1  - Stolarczyk, Th.
A1  - Sánchez-Losa, A.
A1  - Taiuti, M.
A1  - Trovato, A.
A1  - Tselengidou, M.
A1  - Turpin, D.
A1  - Tönnis, C.
A1  - Vallage, B.
A1  - Vallée, C.
A1  - Van Elewyck, V.
A1  - Vivolo, D.
A1  - Wagner, S.
A1  - Wilms, J.
A1  - Zornoza, J.D.
A1  - Zúñiga, J.
T1  - A search for Secluded Dark Matter in the Sun with the ANTARES neutrino telescope
JF  - Journal of Cosmology and Astroparticle Physics
N2  - A search for Secluded Dark Matter annihilation in the Sun using 2007-2012 data of the ANTARES neutrino telescope is presented. Three different cases are considered: a) detection of dimuons that result from the decay of the mediator, or neutrino detection from: b) mediator that decays into a dimuon and, in turn, into neutrinos, and c) mediator that decays directly into neutrinos. As no significant excess over background is observed, constraints are derived on the dark matter mass and the lifetime of the mediator.
KW  - dark matter experiments
KW  - neutrino detectors
KW  - dark matter detectors
KW  - neutrino astronomy
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-189035
VL  - 2016
IS  - 5
ER  - 
TY  - JOUR
A1  - Kernreiter, T.
A1  - Governale, M.
A1  - Zülicke, U.
A1  - Hankiewicz, E. M.
T1  - Anomalous Spin Response and Virtual-Carrier-Mediated Magnetism in a Topological Insulator
JF  - Physical Review X
N2  - We present a comprehensive theoretical study of the static spin response in HgTe quantum wells, revealing distinctive behavior for the topologically nontrivial inverted structure. Most strikingly, the q=0 (long-wavelength) spin susceptibility of the undoped topological-insulator system is constant and equal to the value found for the gapless Dirac-like structure, whereas the same quantity shows the typical decrease with increasing band gap in the normal-insulator regime. We discuss ramifications for the ordering of localized magnetic moments present in the quantum well, both in the insulating and electron-doped situations. The spin response of edge states is also considered, and we extract effective Landé g factors for the bulk and edge electrons. The variety of counterintuitive spin-response properties revealed in our study arises from the system’s versatility in accessing situations where the charge-carrier dynamics can be governed by ordinary Schrödinger-type physics; it mimics the behavior of chiral Dirac fermions or reflects the material’s symmetry-protected topological order.
KW  - spin response
KW  - magnetism
KW  - nanophysics
KW  - topological insulators
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-166582
VL  - 6
IS  - 021010
ER  - 
TY  - JOUR
A1  - Hsu, Pin-Jui
A1  - Kügel, Jens
A1  - Kemmer, Jeannette
A1  - Toldin, Francesco Parisen
A1  - Mauerer, Tobias
A1  - Vogt, Matthias
A1  - Assaad, Fakher
A1  - Bode, Matthias
T1  - Coexistence of charge and ferromagnetic order in fcc Fe
JF  - Nature Communications
N2  - Phase coexistence phenomena have been intensively studied in strongly correlated materials where several ordered states simultaneously occur or compete. Material properties critically depend on external parameters and boundary conditions, where tiny changes result in qualitatively different ground states. However, up to date, phase coexistence phenomena have exclusively been reported for complex compounds composed of multiple elements. Here we show that charge- and magnetically ordered states coexist in double-layer Fe/Rh(001). Scanning tunnelling microscopy and spectroscopy measurements reveal periodic charge-order stripes below a temperature of 130 K. Close to liquid helium temperature, they are superimposed by ferromagnetic domains as observed by spin-polarized scanning tunnelling microscopy. Temperature-dependent measurements reveal a pronounced cross-talk between charge and spin order at the ferromagnetic ordering temperature about 70 K, which is successfully modelled within an effective Ginzburg–Landau ansatz including sixth-order terms. Our results show that subtle balance between structural modifications can lead to competing ordering phenomena.
KW  - ferromagnetism
KW  - phase transitions and critical phenomena
KW  - coexistence
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-173969
VL  - 7
ER  - 
TY  - JOUR
A1  - Adrián-Martínez, S.
A1  - Albert, A.
A1  - André, M.
A1  - Anghinolfi, M.
A1  - Anton, G.
A1  - Ardid, M.
A1  - Aubert, J.-J.
A1  - Avgitas, T.
A1  - Baret, B.
A1  - Barrios-Martí, J.
A1  - Basa, S.
A1  - Bertin, V.
A1  - Biagi, S.
A1  - Bormuth, R.
A1  - Bouwhuis, M.C.
A1  - Bruijn, R.
A1  - Brunner, J.
A1  - Busto, J.
A1  - Capone, A.
A1  - Caramete, L.
A1  - Carr, J.
A1  - Celli, S.
A1  - Chiarusi, T.
A1  - Circella, M.
A1  - Coleiro, A.
A1  - Coniglione, R.
A1  - Constantini, H.
A1  - Coyle, P.
A1  - Creusot, A.
A1  - Deschamps, A.
A1  - De Bonis, G.
A1  - Distefano, C.
A1  - Donzaud, C.
A1  - Dornic, D.
A1  - Drouhin, D.
A1  - Eberl, T.
A1  - El Bojaddaini, I.
A1  - Elsässer, D.
A1  - Enzenhöfer, A.
A1  - Fehn, K.
A1  - Felis, I.
A1  - Fusco, L.A.
A1  - Galatà, S.
A1  - Gay, P.
A1  - Geißelsöder, S.
A1  - Geyer, K.
A1  - Giordano, V.
A1  - Gleixner, A.
A1  - Glotin, H.
A1  - Gracia-Ruiz, R.
A1  - Graf, K.
A1  - Hallmann, S.
A1  - van Haren, H.
A1  - Heijboer, A.J.
A1  - Hello, Y.
A1  - Hernández-Rey, J.J.
A1  - Hößl, J.
A1  - Hofestädt, J.
A1  - Hugon, C.
A1  - Illuminati, G.
A1  - James, C.W.
A1  - de Jong, M.
A1  - Kadler, M.
A1  - Kalekin, O.
A1  - Katz, U.
A1  - Kießling, D.
A1  - Kouchner, A.
A1  - Kreter, M.
A1  - Kreykenbohm, I.
A1  - Kulikovskiy, V.
A1  - Lachaud, C.
A1  - Lahmann, R.
A1  - Lefèvre, D.
A1  - Leonora, E.
A1  - Loucatos, S.
A1  - Marcelin, M.
A1  - Margiotta, A.
A1  - Marinelli, A.
A1  - Martínez-Mora, J.A.
A1  - Mathieu, A.
A1  - Michael, T.
A1  - Migliozzi, P.
A1  - Moussa, A.
A1  - Mueller, C.
A1  - Nezri, E.
A1  - Pavalas, G.E.
A1  - Pellegrino, C.
A1  - Perrina, C.
A1  - Piattelli, P.
A1  - Popa, V.
A1  - Pradier, T.
A1  - Racca, C.
A1  - Riccobene, G.
A1  - Roensch, K.
A1  - Saldaña, M.
A1  - Samtleben, D.F.E.
A1  - Sánchez-Losa, A.
A1  - Sanguineti, M.
A1  - Sapienza, P.
A1  - Schnabel, J.
A1  - Schüssler, F.
A1  - Seitz, T.
A1  - Sieger, C.
A1  - Spurio, M.
A1  - Stolarczyk, Th.
A1  - Taiuti, M.
A1  - Trovato, A.
A1  - Tselengidou, M.
A1  - Turpin, D.
A1  - Tönnis, C.
A1  - Vallage, B.
A1  - Vallée, C.
A1  - Van Elewyck, V.
A1  - Visser, E.
A1  - Vivolo, D.
A1  - Wagner, S.
A1  - Wilms, J.
A1  - Zornoza, J.D.
A1  - Zúñiga, J.
T1  - Constraints on the neutrino emission from the Galactic Ridge with the ANTARES telescope
JF  - Physics Letters B
N2  - A highly significant excess of high-energy astrophysical neutrinos has been reported by the IceCube Collaboration. Some features of the energy and declination distributions of IceCube events hint at a North/South asymmetry of the neutrino flux. This could be due to the presence of the bulk of our Galaxy in the Southern hemisphere. The ANTARES neutrino telescope, located in the Mediterranean Sea, has been taking data since 2007. It offers the best sensitivity to muon neutrinos produced by galactic cosmic ray interactions in this region of the sky. In this letter a search for an extended neutrino flux from the Galactic Ridge region is presented. Different models of neutrino production by cosmic ray propagation are tested. No excess of events is observed and upper limits for different neutrino flux spectral indices Γ are set. For Γ=2.4 the 90% confidence level flux upper limit at 100 TeV for one neutrino flavour corresponds to Φ\(^{1f}_{0}\) (100 TeV) = 2.0 · 10\(^{−17}\) GeV\(^{−1}\) cm\(^{−2}\)s\(^{−1}\)sr\(^{−1}\). Under this assumption, at most two events of the IceCube cosmic candidates can originate from the Galactic Ridge. A simple power-law extrapolation of the Fermi-LAT flux to account for IceCube High Energy Starting Events is excluded at 90% confidence level.
KW  - neutrino emission
KW  - Galactic Ridge
KW  - ANTARES telescope
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-166608
VL  - 760
ER  - 
TY  - JOUR
A1  - Denner, Ansgar
A1  - Jenniches, Laura
A1  - Lang, Jean-Nicolas
A1  - Sturm, Christian
T1  - Gauge-independent (MS)over-bar renormalization in the 2HDM
JF  - Journal of High Energy Physics
N2  - We present a consistent renormalization scheme for the CP-conserving Two-Higgs-Doublet Model based on (MS)over-bar renormalization of the mixing angles and the soft-Z 2-symmetry-breaking scale M sb in the Higgs sector. This scheme requires to treat tadpoles fully consistently in all steps of the calculation in order to provide gauge-independent S-matrix elements. We show how bare physical parameters have to be defined and verify the gauge independence of physical quantities by explicit calculations in a general R ξ -gauge. The procedure is straightforward and applicable to other models with extended Higgs sectors. In contrast to the proposed scheme, the (MS)over-bar renormalization of the mixing angles combined with popular on-shell renormalization schemes gives rise to gauge-dependent results already at the one-loop level. We present explicit results for electroweak NLO corrections to selected processes in the appropriately renormalized Two-Higgs-Doublet Model and in particular discuss their scale dependence.
KW  - NLO Computations
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-166402
VL  - 09
IS  - 115
ER  - 
TY  - JOUR
A1  - Bechtle, Philip
A1  - Camargo-Molina, José Eliel
A1  - Desch, Klaus
A1  - Dreiner, Herbert K.
A1  - Hamer, Matthias
A1  - Krämer, Michael
A1  - O'Leary, Ben
A1  - Porod, Werner
A1  - Sarrazin, Björn
A1  - Stefaniak, Tim
A1  - Uhlenbrock, Mathias
A1  - Wienemann, Peter
T1  - Killing the cMSSM softly
JF  - The European Physical Journal C
N2  - We investigate the constrained Minimal Supersymmetric Standard Model (cMSSM) in the light of constraining experimental and observational data from precision measurements, astrophysics, direct supersymmetry searches at the LHC and measurements of the properties of the Higgs boson, by means of a global fit using the program Fittino. As in previous studies, we find rather poor agreement of the best fit point with the global data. We also investigate the stability of the electro-weak vacuum in the preferred region of parameter space around the best fit point. We find that the vacuum is metastable, with a lifetime significantly longer than the age of the Universe. For the first time in a global fit of supersymmetry, we employ a consistent methodology to evaluate the goodness-of-fit of the cMSSM in a frequentist approach by deriving p values from large sets of toy experiments. We analyse analytically and quantitatively the impact of the choice of the observable set on the p value, and in particular its dilution when confronting the model with a large number of barely constraining measurements. Finally, for the preferred sets of observables, we obtain p values for the cMSSM below 10 %, i.e. we exclude the cMSSM as a model at the 90 % confidence level.
KW  - Dark Matter
KW  - Higgs Boson
KW  - Higgs Mass
KW  - Supersymmetry Breaking
KW  - Light Supersymmetric Particle
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-165045
VL  - 76
IS  - 96
ER  - 
TY  - JOUR
A1  - Adrián-Martínez, S.
A1  - Ageron, M.
A1  - Aharonian, F.
A1  - Aiello, S.
A1  - Albert, A.
A1  - Ameli, F.
A1  - Annasontzis, E.
A1  - Andre, M.
A1  - Androulakis, G.
A1  - Anghinolfi, M.
A1  - Anton, G.
A1  - Ardid, M.
A1  - Avgitas, T.
A1  - Barbarino, G.
A1  - Baret, B.
A1  - Barrios-Martí, J.
A1  - Belhorma, B.
A1  - Belias, A.
A1  - Berbee, A.
A1  - van den Berg, A.
A1  - Bertin, V.
A1  - Beurthey, S.
A1  - van Beeveren, V.
A1  - Beverini, N.
A1  - Biagi, S.
A1  - Biagioni, A.
A1  - Billault, M.
A1  - Bondì, M.
A1  - Bormuth, R.
A1  - Bouhadef, B.
A1  - Bourlis, G.
A1  - Bourret, S.
A1  - Boutonnet, C.
A1  - Bouwhuis, M.
A1  - Bozza, C.
A1  - Bruijn, R.
A1  - Brunner, J.
A1  - Buis, E.
A1  - Busto, J.
A1  - Cacopardo, G.
A1  - Caillat, L.
A1  - Calmai, M.
A1  - Calvo, D.
A1  - Capone, A.
A1  - Caramete, L.
A1  - Cecchini, S.
A1  - Celli, S.
A1  - Champion, C.
A1  - Cherkaoui El Moursli, R.
A1  - Cherubini, S.
A1  - Chiarusi, T.
A1  - Circella, M.
A1  - Classen, L.
A1  - Cocimano, R.
A1  - Coelho, J. A. B.
A1  - Coleiro, A.
A1  - Colonges, S.
A1  - Coniglione, R.
A1  - Cordelli, M.
A1  - Cosquer, A.
A1  - Coyle, P.
A1  - Creusot, A.
A1  - Cuttone, G.
A1  - D'Amico, A.
A1  - De Bonis, G.
A1  - De Rosa, G.
A1  - De Sio, C.
A1  - Di Capua, F.
A1  - Di Palma, I.
A1  - Díaz García, A. F.
A1  - Distefano, C.
A1  - Donzaud, C.
A1  - Dornic, D.
A1  - Dorosti-Hasankiadeh, Q.
A1  - Drakopoulou, E.
A1  - Drouhin, D.
A1  - Drury, L.
A1  - Durocher, M.
A1  - Eberl, T.
A1  - Eichie, S.
A1  - van Eijk, D.
A1  - El Bojaddaini, I.
A1  - El Khayati, N.
A1  - Elsaesser, D.
A1  - Enzenhöfer, A.
A1  - Fassi, F.
A1  - Favali, P.
A1  - Fermani, P.
A1  - Ferrara, G.
A1  - Filippidis, C.
A1  - Frascadore, G.
A1  - Fusco, L. A.
A1  - Gal, T.
A1  - Galatà, S.
A1  - Garufi, F.
A1  - Gay, P.
A1  - Gebyehu, M.
A1  - Giordano, V.
A1  - Gizani, N.
A1  - Gracia, R.
A1  - Graf, K.
A1  - Grégoire, T.
A1  - Grella, G.
A1  - Habel, R.
A1  - Hallmann, S.
A1  - van Haren, H.
A1  - Harissopulos, S.
A1  - Heid, T.
A1  - Heijboer, A.
A1  - Heine, E.
A1  - Henry, S.
A1  - Hernández-Rey, J. J.
A1  - Hevinga, M.
A1  - Hofestädt, J.
A1  - Hugon, C. M. F.
A1  - Illuminati, G.
A1  - James, C. W.
A1  - Jansweijer, P.
A1  - Jongen, M.
A1  - de Jong, M.
A1  - Kadler, M.
A1  - Kalekin, O.
A1  - Kappes, A.
A1  - Katz, U. F.
A1  - Keller, P.
A1  - Kieft, G.
A1  - Kießling, D.
A1  - Koffeman, E. N.
A1  - Kooijman, P.
A1  - Kouchner, A.
A1  - Kulikovskiy, V.
A1  - Lahmann, R.
A1  - Lamare, P.
A1  - Leisos, A.
A1  - Leonora, E.
A1  - Lindsey Clark, M.
A1  - Liolios, A.
A1  - Llorenz Alvarez, C. D.
A1  - Lo Presti, D.
A1  - Löhner, H.
A1  - Lonardo, A.
A1  - Lotze, M.
A1  - Loucatos, S.
A1  - Maccioni, E.
A1  - Mannheim, K.
A1  - Margiotta, A.
A1  - Marinelli, A.
A1  - Mariş, O.
A1  - Markou, C.
A1  - Martínez-Mora, J. A.
A1  - Martini, A.
A1  - Mele, R.
A1  - Melis, K. W.
A1  - Michael, T.
A1  - Migliozzi, P.
A1  - Migneco, E.
A1  - Mijakowski, P.
A1  - Miraglia, A.
A1  - Mollo, C. M.
A1  - Mongelli, M.
A1  - Morganti, M.
A1  - Moussa, A.
A1  - Musico, P.
A1  - Musumeci, M.
A1  - Navas, S.
A1  - Nicoleau, C. A.
A1  - Olcina, I.
A1  - Olivetto, C.
A1  - Orlando, A.
A1  - Papaikonomou, A.
A1  - Papaleo, R.
A1  - Păvălaş, G. E.
A1  - Peek, H.
A1  - Pellegrino, C.
A1  - Perrina, C.
A1  - Pfutzner, M.
A1  - Piattelli, P.
A1  - Pikounis, K.
A1  - Poma, G. E.
A1  - Popa, V.
A1  - Pradier, T.
A1  - Pratolongo, F.
A1  - Pühlhofer, G.
A1  - Pulvirenti, S.
A1  - Quinn, L.
A1  - Racca, C.
A1  - Raffaelli, F.
A1  - Randazzo, N.
A1  - Rapidis, P.
A1  - Razis, P.
A1  - Real, D.
A1  - Resvanis, L.
A1  - Reubelt, J.
A1  - Riccobene, G.
A1  - Rossi, C.
A1  - Rovelli, A.
A1  - Saldaña, M.
A1  - Salvadori, I.
A1  - Samtleben, D. F. E.
A1  - Sánchez García, A.
A1  - Sánchez Losa, A.
A1  - Sanguineti, M.
A1  - Santangelo, A.
A1  - Santonocito, D.
A1  - Sapienza, P.
A1  - Schimmel, F.
A1  - Schmelling, J.
A1  - Sciacca, V.
A1  - Sedita, M.
A1  - Seitz, T.
A1  - Sgura, I.
A1  - Simeone, F.
A1  - Siotis, I.
A1  - Sipala, V.
A1  - Spisso, B.
A1  - Spurio, M.
A1  - Stavropoulos, G.
A1  - Steijger, J.
A1  - Stellacci, S. M.
A1  - Stransky, D.
A1  - Taiuti, M.
A1  - Tayalati, Y.
A1  - Tézier, D.
A1  - Theraube, S.
A1  - Thompson, L.
A1  - Timmer, P.
A1  - Tönnis, C.
A1  - Trasatti, L.
A1  - Trovato, A.
A1  - Tsirigotis, A.
A1  - Tzamarias, S.
A1  - Tzamariudaki, E.
A1  - Vallage, B.
A1  - Van Elewyk, V.
A1  - Vermeulen, J.
A1  - Vicini, P.
A1  - Viola, S.
A1  - Vivolo, D.
A1  - Volkert, M.
A1  - Voulgaris, G.
A1  - Wiggers, L.
A1  - Wilms, J.
A1  - de Wolf, E.
A1  - Zachariadou, K.
A1  - Zornoza, J. D.
A1  - Zúñiga, J.
T1  - Letter of intent for KM3NeT 2.0
JF  - Journal of Physics G-Nuclear and Particle Physics
N2  - The main objectives of the KM3NeT Collaboration are (i) the discovery and subsequent observation of high-energy neutrino sources in the Universe and (ii) the determination of the mass hierarchy of neutrinos. These objectives are strongly motivated by two recent important discoveries, namely: (1) the high-energy astrophysical neutrino signal reported by IceCube and (2) the sizable contribution of electron neutrinos to the third neutrino mass eigenstate as reported by Daya Bay, Reno and others. To meet these objectives, the KM3NeT Collaboration plans to build a new Research Infrastructure consisting of a network of deep-sea neutrino telescopes in the Mediterranean Sea. A phased and distributed implementation is pursued which maximises the access to regional funds, the availability of human resources and the synergistic opportunities for the Earth and sea sciences community. Three suitable deep-sea sites are selected, namely off-shore Toulon (France), Capo Passero (Sicily, Italy) and Pylos (Peloponnese, Greece). The infrastructure will consist of three so-called building blocks. A building block comprises 115 strings, each string comprises 18 optical modules and each optical module comprises 31 photo-multiplier tubes. Each building block thus constitutes a three-dimensional array of photo sensors that can be used to detect the Cherenkov light produced by relativistic particles emerging from neutrino interactions. Two building blocks will be sparsely configured to fully explore the IceCube signal with similar instrumented volume, different methodology, improved resolution and
KW  - neutrino astronomy
KW  - eutrino physics
KW  - deep sea neutrino telescope
KW  - neutrino mass hierarchy
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-188050
VL  - 43
IS  - 8
ER  - 
TY  - JOUR
A1  - Adrián-Martínez, S.
A1  - Albert, A.
A1  - André, M.
A1  - Anton, G.
A1  - Ardid, M.
A1  - Aubert, J.-J.
A1  - Avgitas, T.
A1  - Baret, B.
A1  - Barrios-Martí, J.
A1  - Basa, S.
A1  - Bertin, V.
A1  - Biagi, S.
A1  - Bormuth, R.
A1  - Bouwhuis, M.C.
A1  - Bruijn, R.
A1  - Brunner, J.
A1  - Busto, J.
A1  - Capone, A.
A1  - Caramete, L.
A1  - Carr, J.
A1  - Celli, S.
A1  - Chiarusi, T.
A1  - Circella, M.
A1  - Coleiro, A.
A1  - Coniglione, R.
A1  - Costantini, H.
A1  - Coyle, P.
A1  - Creusot, A.
A1  - Deschamps, A.
A1  - De Bonis, G.
A1  - Distefano, C.
A1  - Donzaud, C.
A1  - Dornic, D.
A1  - Drouhin, D.
A1  - Eberl, T.
A1  - El Bojaddaini, I.
A1  - Elsässer, D.
A1  - Enzenhöfer, A.
A1  - Fehn, K.
A1  - Felis, I.
A1  - Fusco, L.A.
A1  - Galatà, S.
A1  - Gay, P.
A1  - Geißelsöder, S.
A1  - Geyer, K.
A1  - Giordano, V.
A1  - Gleixner, A.
A1  - Glotin, H.
A1  - Gracia-Ruiz, R.
A1  - Graf, K.
A1  - Hallmann, S.
A1  - van Haren, H.
A1  - Heijboer, A.J.
A1  - Hello, Y.
A1  - Hernández-Rey, J.J.
A1  - Hößl, J.
A1  - Hofestädt, J.
A1  - Hugon, C.
A1  - Illuminati, G.
A1  - James, C.W.
A1  - de Jong, M.
A1  - Jongen, M.
A1  - Kadler, M.
A1  - Kalekin, O.
A1  - Katz, U.
A1  - Kießling, D.
A1  - Kouchner, A.
A1  - Kreter, M.
A1  - Kreykenbohm, I.
A1  - Kulikovskiy, V.
A1  - Lachaud, C.
A1  - Lahmann, R.
A1  - Lefèvre, D.
A1  - Leonora, E.
A1  - Loucatos, S.
A1  - Marcelin, M.
A1  - Margiotta, A.
A1  - Marinelli, A.
A1  - Martínez-Mora, J.A.
A1  - Mathieu, A.
A1  - Melis, K.
A1  - Michael, T.
A1  - Migliozzi, P.
A1  - Moussa, A.
A1  - Mueller, C.
A1  - Nezri, E.
A1  - Pavalas, G.E.
A1  - Pellegrino, C.
A1  - Perrina, C.
A1  - Piattelli, P.
A1  - Popa, V.
A1  - Pradier, T.
A1  - Racca, C.
A1  - Riccobene, G.
A1  - Roensch, K.
A1  - Saldaña, M.
A1  - Samtleben, D.F.E.
A1  - Sánchez-Losa, A.
A1  - Sanguineti, M.
A1  - Sapienza, P.
A1  - Schnabel, J.
A1  - Schüssler, F.
A1  - Seitz, T.
A1  - Sieger, C.
A1  - Spurio, M.
A1  - Stolarczyk, Th.
A1  - Taiuti, M.
A1  - Tönnis, C.
A1  - Trovato, A.
A1  - Tselengidou, M.
A1  - Turpin, D.
A1  - Vallage, B.
A1  - Vallée, C.
A1  - Van Elewyck, V.
A1  - Vivolo, D.
A1  - Wagner, S.
A1  - Wilms, J.
A1  - Zornoza, J.D.
A1  - Zúñiga, J.
T1  - Limits on dark matter annihilation in the sun using the ANTARES neutrino telescope
JF  - Physics Letters B
N2  - A search for muon neutrinos originating from dark matter annihilations in the Sun is performed using the data recorded by the ANTARES neutrino telescope from 2007 to 2012. In order to obtain the best possible sensitivities to dark matter signals, an optimisation of the event selection criteria is performed taking into account the background of atmospheric muons, atmospheric neutrinos and the energy spectra of the expected neutrino signals. No significant excess over the background is observed and 90% C.L. upper limits on the neutrino flux, the spin-dependent and spin-independent WIMP-nucleon cross-sections are derived for WIMP masses ranging from 50 GeV to 5 TeV for the annihilation channels WIMP + WIMP→ b\(\overline{b}\), W\(^{+}\)W\(^{−}\) and τ\(^{+}\)τ\(^{−}\).
KW  - dark matter
KW  - WIMP
KW  - neutralino
KW  - indirect detection
KW  - neutrino telescope
KW  - sun
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-166642
VL  - 759
ER  - 
TY  - THES
A1  - Trüstedt, Jonas Elias
T1  - Long-wavelength radio observations of blazars with the Low-Frequency Array (LOFAR)
T1  - Beobachtungen von Blazaren bei langen Radio-Wellenlängen mit dem Low-Frequency Array (LOFAR)
N2  - Aktive Galaxienkerne (AGN) gehören zu den hellsten Objekten in unserem Universum. Diese Galaxien werden als aktiv bezeichnet, da ihre Zentralregion heller ist als alle Sterne in einer Galaxie zusammen beitragen könnten. Das Zentrum besteht aus einem supermassiven schwarzen Loch, das von einer Akkretionsscheibe und weiter außerhalb von einem Torus aus Staub umgeben ist. Diese AGN können über das ganze elektromagnetische Spektrum verteilt gefunden werden, von Radiowellen über Wellenlängen im optischen und Röntgenbereich bis hin zur $\gamma$-Strahlung. Allerdings sind nicht alle Objekte bei jeder Wellenlänge detektierbar. In dieser Arbeit werden überwiegend Blazare bei niedrigen Radiofrequenzen untersucht. Blazare gehören zu den radio-lauten AGN, welche üblicherweise stark kollimierte Jets senkrecht zur Akkretionsscheibe aussenden. Bei Blazaren sind diese Jets in die Richtung des Beobachters gerichtet und ihre Emissionen sind stark variabel. \\
AGN werden anhand ihres Erscheinungsbildes verschiedenen Untergruppen zugeordnet. Diese Untergruppen werden in einem vereinheitlichen AGN Modell zusammengeführt, welches besagt, dass diese Objekte sich nur in ihrer Luminosität und ihrem Winkel zur Sichtlinie unterscheiden. Blazare sind diejenigen Objekte, deren Jets in unsere Sichtrichtung zeigen, während die Objekte deren Jets eher senkrecht zur Sichtlinie orientiert sind als Radiogalaxien bezeichnet werden. Daraus folgt, dass Blazare die Gegenstücke zu Radiogalaxien mit einem anderen Winkel zur Sichtlinie sind. Diese Beziehung soll unter anderem in dieser Arbeit untersucht werden. \\
Nach ihrer Entdeckung in den 1940er Jahren wurden die aktiven Galaxien bei allen zugänglichen Wellenlängen untersucht. Durch die Entwicklung von Interferometern aus Radioteleskopen, welche eine erhöhte Auflösung bieten, konnten die Beobachtungen stark verbessert werden. In den letzten 20 Jahren wurden viele AGN regelmäßig beobachtet. Dies erfolgte unter anderem durch Programme wie dem MOJAVE Programm, welches 274 AGNs regelmäßig mithilfe der Technik der ``Very Long Baseline Interferometry" (VLBI) beobachtet. Durch diese Beobachtungen konnten Informationen zur Struktur und Entwicklung der AGN und Jets gesammelt werden. Allerdings sind die Prozesse zur Bildung von Jets und deren Kollimation noch nicht vollständig bekannt. Durch relativistische Effekte ist es schwierig die eigentlichen Größen der Jets anstelle der scheinbaren zu messen. Um die intrinsische Energie von Jets zu messen, sollen die ausgedehnten Emissionsregionen untersucht werden, in denen die Jets enden und mit dem Intergalaktischen Medium interagieren. Beobachtungen bei niedrigen Radiofrequenzen sind empfindlicher um solche ausgedehnte, diffuse Emissionsregionen zu detektieren. \\
Seit Dezember 2012 ist ein neues Radioteleskop für niedrige Frequenzen in Betrieb, dessen Stationen aus Dipolantennen besteht. Die meisten dieser Stationen sind in den Niederlanden verteilt (38 Stationen) und werden durch 12 internationale Stationen in Deutschland, Frankreich, Schweden, Polen und England ergänzt. Dieses Instrument trägt den Namen ``Low Frequency Array'' (LOFAR). LOFAR bietet die Möglichkeit bei Frequenzen von 30--250 MHz bei einer höheren Auflösung als bisherige Radioteleskope zu beobachten (Winkelauflösungen unter 1 arcsec für das gesamte Netzwerk aus Teleskopen). \\
Diese Arbeit behandelt die Ergebnisse von Blazaruntersuchungen mithilfe von LOFAR-Beobachtungen. Dafür wurden AGNs aus dem MOJAVE Programm verwendet um von den bisherigen Multiwellenlängen-Beobachtungen und Untersuchungen der Kinematik zu profitieren. Das ``Multifrequency Snapshot Sky Survey'' (MSSS) Projekt hat den gesamten Nordhimmel mit kurzen Beobachtungen abgerastert. Aus dem daraus resultierenden vorläufigen Katalog wurden die Flussdichten und Spektralindizes für MOJAVE-Blazare untersucht. In den kurzen Beobachtungen von MSSS sind nur die Stationen in den Niederlanden verwendet worden, wodurch Auflösung und Sensitivität begrenzt sind. Für die Erstellung des vorläufigen Kataloges wurde die Auflösung auf $\sim$120 arcsec beschränkt. Ein weiterer Vorteil der MOJAVE Objekte ist die regelmäßige Beobachtung der AGN mit dem ``Owens Vally Radio Observatory'' zur Erstellung von Lichtkurven bei 15 GHz. Dadurch ist es möglich nahezu zeitgleiche Flussdichtemessungen bei 15 GHz zu den entsprechenden MSSS-Beobachtungen zu bekommen. Da diese Beobachtungen zu ähnlichen Zeitpunkten durchgeführt wurden sind diese Flussdichten weniger von der Variabilität der Blazare beeinflusst. Die Spektralindizes berechnet aus den Flussdichten von MSSS und OVRO können verwendet werden um den Anteil an ausgedehnter Emission der AGNs abzuschätzen. \\
Im Vergleich der Flussdichten aus dem MSSS Katalog mit den Beobachtungen von OVRO fällt auf, dass die Flussdichten bei niedrigen Frequenzen tendenziell höher sind, was durch den höheren Anteil an ausgedehnter Struktur zu erwarten ist. Die Spektralindexverteilung zwischen MSSS und OVRO zeigt ihren höchsten Wert bei $\sim-0.2$. In der Verteilung existieren Objekte mit steilerem Spektralindex durch den höheren Anteil von ausgedehnter Emission in der Gesamtflussdichte, doch über die Hälfte der untersuchten Objekte besitzt flache Spektralindizes. Die flachen Spektralindizes bedeuten, dass die Emissionen dieser Objekte größtenteils von relativistischen Effekten beeinflusst sind, die schon aus Beobachtungen bei GHz-Frequenzen bekannt sind. \\
Durch neue Auswertung der MSSS Beobachtungsdaten konnten Bilder bei einer verbesserten Auflösung von $\sim$20--30 arcsec erstellt werden, wodurch bei einigen Blazaren ausgedehnte Struktur detektiert werden konnte. Diese höher aufgelösten Bilder sind allerdings nicht komplett kalibriert und können somit nur für strukturelle Informationen verwendet werden. Die Überarbeitung der Beobachtungsdaten konnte für 93 Objekte für ein Frequenzband durchgeführt werden. Für 45 der 93 Objekte konnten sogar alle vorhandenen Frequenzbänder überarbeitet werden und dadurch gemittelte Bilder erstellt werden. Diese Bilder werden in dieser Arbeit vorgestellt. Die resultierenden Bilder mit verbesserter Auflösung wurden verwendet um Objekte auszuwählen, die mit allen LOFAR-Stationen beobachtet und auf ausgedehnte Struktur untersucht werden können. \\
Im zweiten Teil der Arbeit werden die Ergebnisse von internationalen LOFAR Beobachtungen von vier Blazaren präsentiert. Da sich die Auswertung und Kalibration von internationalen LOFAR Beobachtungen noch in der Entwicklung befindet, wurde ein Schwerpunkt auf die Kalibration und deren Beschreibung gelegt. Die Kalibration kann zwar noch verbessert werden, aber die Bilder aus der angewandten Kalibration erreichen eine Auflösung von unter 1 arcsec. Die Struktur der untersuchten vier Blazare entspricht den Erwartungen für Radiogalaxien unter einem anderen Sichtwinkel. Durch die gemessenen Flussdichten der ausgedehnten Struktur aus den Helligkeitsverteilungen konnte die Luminosität der ausgedehnten Emissionen berechnet werden. Im Vergleich mit den Luminositäten, die von Radiogalaxien bekannt sind, entsprechen auch diese Werte den Erwartungen des vereinheitlichten AGN Modells. \\
Durch die in dieser Arbeit vorgestellte Kalibration können noch mehr Blazare mit LOFAR inklusive den internationalen Stationen beobachtet werden und somit Bilder der Struktur bei ähnlicher Auflösung erstellt werden. Durch eine erhöhte Anzahl von untersuchten Blazaren könnten anschließend auch statistisch signifikante Ergebnisse erzielt werden.\\
N2  - Active galactic nuclei (AGNs) are among the brightest sources in our universe. These galaxies are considered active because their central region is brighter than the luminosities of all stars in a galxies can provide. In their center is a supermassive black hole (SMBH) surrounded by an accretion disk and further out a dusty torus. AGN can be found with emission over the whole electromagnetic spectrum, starting at radio frequencies over optical and X-ray emission up to the $\gamma$-rays. Not all of these sources are detected in each frequency regime. In this work mainly blazars are examined at low radio frequencies. Blazars are a subclass of radio-loud AGN. These radio-loud sources usually exhibit highly collimated jets perpendicular to the accretion disk. For blazars these jets are pointed in the direction of the observer and their emission is highly variable. \\
AGN are classified in different subclasses based on their morphology. These different subclasses are combined in the AGN unification model, which explains the different morphologies by having sources only varying in their luminosities and their angle to the line of sight to the observer. Blazars are these targets, where the jet is pointing towards the observer, while the AGN observed edge on are called radio galaxies. This means that blazars should be the counterparts to radio galaxies seen from a different angle. Testing this is one of the goals in this work. \\
After the discovery of AGN in the 1940s these objects have been studied at all wavelengths. With the development of interferometry with radio telescopes the angular resolution for radio observations could be improved. In the last 20 years many AGN are regularly monitored. One of these monitoring programs is the MOJAVE program, monitoring 274 AGNs with using the Very Long Baseline Interferometry (VLBI) technique. The monitoring provides information on the evolution and structure of AGN and their jets. However, the mechanisms of the jet formation and their collimation are not fully understood. Due to relativistic effects it is difficult to obtain intrinsic instead of apparent parameters of these jets. One approach to get closer to the intrinsic jet power is by observing the regions, in which the jets end and interact with the intergalactic medium. Observations at lower radio frequencies are more sensitive for extended diffuse emission. \\
Since December 2012 a new radio telescope for low frequencies is observing. It is a telescope with stations consisting of dipole antennas. The major part of the array located in the Netherlands (38 stations) with 12 additional international stations in Germany, France, Sweden, Poland and the United Kingdom. This instrument is called the Low Frequency Array (LOFAR). LOFAR offers the possibility to observe at frequencies between 30--250 MHz in combination with angular resolution (below 1 arcsec for the full array), which was not available with previous telescopes. \\
In this work results of blazar studies with LOFAR observations are presented. To take advantage of a large database with multi-wavelength observations and kinematic studies the MOJAVE 1.5 Jy flux limited sample was chosen. Based on the preliminary results of the LOFAR Multifrequency Snapshot Sky Survey (MSSS) the flux densities and spectral indices of blazars of the MOJAVE sample are examined. 125 counterparts of MOJAVE blazars were found in the MSSS catalog. Since the MSSS observations only contain the stations in the Netherlands and observes in snapshots, the angular resolution and the sensitivity is limited. The first MSSS catalog was produced with an angular resolution of $\sim$120 arcsec and a sensitivity of $\sim$50--100 mJy. Another advantage of the MOJAVE sample is the monitoring of these sources with the Owens Valley Radio Observatory (OVRO) at 15 GHz to produce radio lightcurves. With these observations it is possible to get quasi-simultaneous flux densities at 15 GHz for the corresponding MSSS observations. By having quasi-simultaneous observations the variability of the blazars affects the flux densities less than with the use of archival data. The spectral indices obtained by the combination of MSSS and OVRO flux densities can be used to estimate the contribution of the diffuse extended emission for these AGNs. \\
Comparing the MSSS catalog with the OVRO data points, the flux densities have a tendency to be higher at low frequencies. This is expected due to the higher contribution of extended emission. The broadband spectral index distribution shows a peak at $\sim-0.2$. While some sources seem to have steeper spectral indices meaning that extended emission contributes a large fraction of the total flux density, more than the half of the sample shows flat spectral indices. The flat spectral indices show that the total flux densities of these sources are dominated by their relativistic beamed emission regions, which is the same for the observations at GHz frequencies. \\
To obtain more detailed images of these sources the MSSS measurement sets including sources of the sample were reprocessed to improve the angular resolution to $\sim$30 arcsec. The higher angular resolution reveals extended diffuse emission of several blazars. Since the reimaging results were not fully calibrated only the morphology at this resolution could be examined. However, with the short snapshot observations the images obtained with this strategy are affected from artifacts. The reimaging could be successfully performed for 93 sources in one frequency band. For 45 of these sources all availabe frequency bands could be reprocessed and used to created averaged images. These images are presented in this work. As a results of the reimaging process a pilot sample was defined to observe targets with diffuse extended emission using the whole LOFAR array including the international stations. \\
The second part of this work presents the results of a pilot sample consisting of four blazars observed with the LOFAR international array. Since the calibration of this kind of LOFAR observation is still in development, the main focus was the description of the used calibration strategy. The calibration strategies still has some limitation but resulted in images with angular resolutions of less than 1 arcsec. The morphology of all four blazars show features confirming the expectations of their counterpart radio galaxies. With the flux densities of the extended emission found in these brightness distributions the extended radio luminosities are calculated. Comparing these to the radio galaxy classifications also confirm the expectations from the unification model. \\
By extending the sample of observed blazars with LOFAR international in future the calibration strategy can be used to create similar high resolution images. A larger sample can be used to test the unification model with statistical significant results. \\
KW  - Blazar
KW  - Radioastronomie
KW  - Blazars
KW  - Active Galaxies
KW  - Radio Interferometry
KW  - Radio astronomy
KW  - LOFAR
KW  - Aktive Galaxie
KW  - Radioteleskop
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-144406
ER  - 
TY  - THES
A1  - Bolaños-Rosales, Alejandro
T1  - Low Mach Number Simulations of Convective Boundary Mixing in Classical Novae
T1  - Simulationen der konvektiven Mischung in Klassischen Novae im Strömungsbereich kleiner Machzahlen
N2  - Classical novae are thermonuclear explosions occurring on the surface of white dwarfs.
When co-existing in a binary system with a main sequence or more evolved star, mass
accretion from the companion star to the white dwarf can take place if the companion
overflows its Roche lobe. The envelope of hydrogen-rich matter which builds on
top of the white dwarf eventually ignites under degenerate conditions, leading to
a thermonuclear runaway and an explosion in the order of 1046 erg, while leaving
the white dwarf intact. Spectral analyses from the debris indicate an abundance of
isotopes that are tracers of nuclear burning via the hot CNO cycle, which in turn
reveal some sort of mixing between the envelope and the white dwarf underneath.
The exact mechanism is still a matter of debate.
The convection and deflagration in novae develop in the low Mach number regime.
We used the Seven League Hydro code (SLH ), which employs numerical schemes
designed to correctly simulate low Mach number flows, to perform two and three-
dimensional simulations of classical novae. Based on a spherically-symmetric model
created with aid of a stellar evolution code, we developed our own nova model and
tested it on a variety of numerical grids and boundary conditions for validation. We
focused on the evolution of temperature, density and nuclear energy generation rate at
the layers between white dwarf and envelope, where most of the energy is generated,
to understand the structure of the transition region, and its effect on the nuclear
burning. We analyzed the resulting dredge-up efficiency stemming from the convective
motions in the envelope. Our models yield similar results to the literature, but seem
to depend very strongly on the numerical resolution. We followed the evolution of
the nuclear species involved in the CNO cycle and concluded that the thermonuclear
reactions primarily taking place are those of the cold and not the hot CNO cycle.
The reason behind this could be that under the conditions generally assumed for
multi-dimensional simulations, the envelope is in fact not degenerate. We performed
initial tests for 3D simulations and realized that alternative boundary conditions are
needed.
N2  - Klassische Novae sind thermonukleare Explosionen an der Oberfläche von Weißen
Zwergen. Wenn ein solcher sich in einem Doppelsternsystem zusammen mit einem
Hauptreihenstern oder einem späteren Stern befindet, kann Akkretion vom Begleiter
zum Weißen Zwerg stattfinden, falls der Begleitstern seine Roche-Grenze überschre-
itet. Die wasserstoffreiche Hülle, die sich auf der Oberfläche des Sterns bildet, zündet
aufgrund des enormen Gravitationsdrucks in einer Deflagration. Aufgrund der Entar-
tung des Gases führt das nukleare Brennen zu einem thermonuklearen Durchgehen
(engl. runaway)und schließlich zu einer Explosion mit Energien in der Größenord-
nung von 1046 erg. Der Weiße Zwerg bleibt dabei unberührt. Spektralanalysen der
ausgestoßenen Gase deuten auf Isotope hin, die am heißen CNO-Zyklus beteiligt
sind. Dies legt nahe, dass vor oder während der Brennphase eine Durchmischung von
Materie zwischen der akkretierten Hülle und dem Weißen Zwerg stattfinden muss.
Die Konvektion und Deflagration entwickeln sich im Strömungsbereich kleiner
Machzahlen. Wir benutzten den Seven League Hydro code (SLH ), welcher ëber
numerische Verfahren verfügt, die auf einen weiten Bereich von Machzahlen anwend-
bar sind. Daraus errechneten wir Simulationen von Klassischen Novae in zwei und
drei Dimensionen. Basierend auf einem sphärisch-symmetrischen Modell, das wir mit
einem Sternentwicklungscode erstellten, entwickelten wir ein eigenes Nova-Modell.
Wir testeten dies in Kombination mit eienr Reihe von Gittern und Randbedingun-
gen. Anschließend analysierten wir im Detail das Verhalten von Temperatur, Dichte
und nuklearer Energieerzeugungsrate in den Schichten zwischen Weißem Zwerg und
Wasserstoffhülle, wo die Kernfusion hauptsächlich stattfindet, um die Struktur der
Brennzone und deren Einfluss auf die Nukleosynthese zu verstehen. Wir analysierten
die Effizienz der Konvektion, welche Elemente aus dem Weißen Zwerg nach oben in
die Hülle transportiert. Die Ergebnisse entsprechen denen der Literatur, dennoch
hängen sie stark von der numerischen Auflösung ab. Wir untersuchten die Isotopen-
häufigkeit der im CNO-Zyklus beteiligten Elemente, und schloßen hieraus, dass das
Brennen durch den weniger energetischen “kalten” CNO-Zyklus verläuft. Dies kann
darauf zurückgeführt werden, dass unter den Bedingungen, die die Mehrzahl der multi-
dimensionalen Modelle aus der Fachliteratur mit sich bringen, die Wasserstoffhülle
tatsächlich nicht entartet ist. Abschließend simulierten wir testweise 3D-Modelle, aber
neue Randbedingungen sind nötig, um mit den Berechnungen fortfahren zu können.
KW  - Nova
KW  - Weißer Zwerg
KW  - classical novae
KW  - convection
KW  - numerical hydrodynamics
KW  - nuclear reactions
KW  - stellar evolution
KW  - simulation
KW  - low Mach number flows
KW  - numerische Hydrodynamik
KW  - thermonukelare Reaktionen
KW  - Sternentwicklung
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-132863
ER  - 
TY  - JOUR
A1  - Biedermann, B.
A1  - Billoni, M.
A1  - Denner, A.
A1  - Dittmaier, S.
A1  - Hofer, L.
A1  - Jäger, B.
A1  - Salfelder, L.
T1  - Next-to-leading-order electroweak corrections to pp -> W\(^{+}\)W\(^{-}\) -> 4 leptons at the LHC
JF  - JOURNAL OF HIGH ENERGY PHYSICS
N2  - We present results of the first calculation of next-to-leading-order electroweak corrections to W-boson pair production at the LHC that fully takes into account leptonic W-boson decays and off-shell effects. Employing realistic event selections, we discuss the corrections in situations that are typical for the study of W-boson pairs as a signal process or of Higgs-boson decays H → WW∗, to which W-boson pair production represents an irreducible background. In particular, we compare the full off-shell results, obtained treating the W-boson resonances in the complex-mass scheme, to previous results in the so-called double-pole approximation, which is based on an expansion of the loop amplitudes about the W resonance poles. At small and intermediate scales, i.e. in particular in angular and rapidity distributions, the two approaches show the expected agreement at the level of fractions of a percent, but larger differences appear in the TeV range. For transverse-momentum distributions, the differences can even exceed the 10% level in the TeV range where “background diagrams” with one instead of two resonant W bosons gain in importance because of recoil effects.
KW  - NLO Computations
KW  - W-boson
KW  - LHC
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-167790
VL  - 06
IS  - 065
ER  - 
TY  - JOUR
A1  - Denner, Ansgar
A1  - Pellen, Mathieu
T1  - NLO electroweak corrections to off-shell top-antitop production with leptonic decays at the LHC
JF  - Journal of High Energy Phsyics
N2  - For the first time the next-to-leading-order electroweak corrections to the full off-shell production of two top quarks that decay leptonically are presented. This calculation includes all off-shell, non-resonant, and interference effects for the 6-particle phase space. While the electroweak corrections are below one per cent for the integrated cross section, they reach up to 15% in the high-transverse-momentum region of distributions. To support the results of the complete one-loop calculation, we have in addition evaluated the electroweak corrections in two different pole approximations, one requiring two on-shell top quarks and one featuring two on-shell W bosons. While the former deviates by up to 10% from the full calculation for certain distributions, the latter provides a very good description for most observables. The increased centre-of-mass energy of the LHC makes the inclusion of electroweak corrections extremely relevant as they are particularly large in the Sudakov regime where new physics is expected to be probed.
KW  - NLO Computations
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-166415
VL  - 08
IS  - 155
ER  - 
TY  - JOUR
A1  - Denner, Ansgar
A1  - Dittmaier, Stefan
A1  - Hecht, Markus
A1  - Pasold, Christian
T1  - NLO QCD and electroweak corrections to Z + γ production with leptonic Z-boson decays
JF  - JOURNAL OF HIGH ENERGY PHYSICS
N2  - The next-to-leading-order electroweak corrections to pp→l\(^{+}\)l\(^{-}\)/ν¯¯¯ν+γ+X production, including all off-shell effects of intermediate Z bosons in the complex-mass scheme, are calculated for LHC energies, revealing the typically expected large corrections of tens of percent in the TeV range. Contributions from quark-photon and photon-photon initial states are taken into account as well, but their impact is found to be moderate or small. Moreover, the known next-to-leading-order QCD corrections are reproduced. In order to separate hard photons from jets, both a quark-to-photon fragmentation function á la Glover/Morgan and Frixione’s cone isolation are employed. The calculation is available in the form of Monte Carlo programs allowing for the evaluation of arbitrary differential cross sections. Predictions for integrated cross sections are presented for the LHC at 7 TeV, 8 TeV, and 14 TeV, and differential distributions are discussed at 14 TeV for bare muons and dressed leptons. Finally, we consider the impact of anomalous ZZγ and Zγγ couplings.
KW  - NLO computations
KW  - hadronic colliders
KW  - LHC
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-168766
VL  - 02
IS  - 057
ER  - 
TY  - JOUR
A1  - Rahman, SK. Shaid-Ur
A1  - Klein, Thorsten
A1  - Klembt, Sebastian
A1  - Gutowski, Jürgen
A1  - Hommel, Detlef
A1  - Sebald, Kathrin
T1  - Observation of a hybrid state of Tamm plasmons and microcavity exciton polaritons
JF  - Scientific Reports
N2  - We present evidence for the existence of a hybrid state of Tamm plasmons and microcavity exciton polaritons in a II-VI material based microcavity sample covered with an Ag metal layer. The bare cavity mode shows a characteristic anticrossing with the Tamm-plasmon mode, when microreflectivity measurements are performed for different detunings between the Tamm plasmon and the cavity mode. When the Tamm-plasmon mode is in resonance with the cavity polariton four hybrid eigenstates are observed due to the coupling of the cavity-photon mode, the Tamm-plasmon mode, and the heavy- and light-hole excitons. If the bare Tamm-plasmon mode is tuned, these resonances will exhibit three anticrossings. Experimental results are in good agreement with calculations based on the transfer matrix method as well as on the coupled-oscillators model. The lowest hybrid eigenstate is observed to be red shifted by about 13 meV with respect to the lower cavity polariton state when the Tamm plasmon is resonantly coupled with the cavity polariton. This spectral shift which is caused by the metal layer can be used to create a trapping potential channel for the polaritons. Such channels can guide the polariton propagation similar to one-dimensional polariton wires.
KW  - Tamm plasmons
KW  - microcavity exciton polaritons
KW  - hybrid state
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-167617
VL  - 6
IS  - 34392
ER  - 
TY  - THES
A1  - Pasold, Christian
T1  - QCD and electroweak NLO corrections to W + Photon and Z + Photon production including leptonic decays
T1  - QCD und elektroschwache NLO Korrekturen zu W + Photon und Z + Photon Produktion inklusive leptonischer Zerfälle
N2  - At a hadron collider as the LHC or the Tevatron the production of a photon in association with a leptonically decaying vector boson represents an important class of processes. These processes stand out due to a very clean signal of a photon and two leptons. Furthermore they 
provide direct access to the photon–vector-boson couplings and thus an easy opportunity to test the 
gauge sector of the Standard Model. Within the scope of this work we present a full calculation of the next-to-leading-order corrections which include the O (αs) corrections of the strong interaction as well as the electroweak corrections of O (α) including all photon-induced contributions. For the creation of matrix elements we use methods based on Feynman diagrams. The IR singularities are treated with the dipole subtraction technique. In order to separate photons from jets, a quark-to-photon fragmentation function ´a la Glover / Morgan or Frixione’s cone isolation is employed. Moreover, two different scenarios for charged leptons in the fi state were considered. The fi  scenario for dressed leptons assumes that a charged lepton and a photon will be recombined if they are collinear. In the second scenario for bare muons it is assumed that leptons and photon can be separated in a detector also if they are collinear.
For our calculation we implemented all corrections into a fl Monte Carlo program. Be- sides the computation of the total cross section this program is also able to generate diff tial distributions of several experimentally motivated observables. Apart from the expected large electroweak corrections in the high transverse-momentum regions and sizeable corrections in the resonance regions of the transverse or the invariant masses we found photon-induced corrections up to several 10% for high transverse momenta. Within run I at the LHC for 7/8 TeV the experimental accuracy for Vγ production was roughly 10%. Due to the higher luminosity at run II this accuracy 
will be reduced to the level of a few percent so that corrections of the same order within the theoretical predictions might become relevant. In this work we present results for the total cross section at the LHC for 7, 8 and 14 TeV and the corresponding distributions
for 14 TeV.
N2  - An einem Hadron Beschleuniger wie dem LHC oder dem Tevatron spielt die Prozessklasse der Produktion eines Photons in Kombination mit einem leptonisch zerfallenden massiven Eichbosons eine wichtige Rolle. Die Gründe für die große Bedeutung sind zum einen die klare Signatur aus einem Photon und zwei Leptonen als auch der direkte Zugang zu den Kopplungen des Photons an die massiven Eichbosonen und damit die Möglichkeit den Eichsektor des Standard-Modells der Elementarteilchenphysik zu testen.
Um die Präzision der theoretischen Vorhersagen weiter zu erhöhen wurde im Rahmen dieser Arbeit eine vollständige Berechnung der Korrekturen in nächstführender Ordnung durchgeführt. 
Diese umfassen alle Korrekturen der starken Wechselwirkung von O (αs) sowie die elektroschwachen 
Korrekturen von O (α) inklusive aller photon-induzierten Beiträge. Zur Erzeugung von Matrixelementen wurde dabei auf Feynman-Diagramm basierte Methoden zurückgegriffen. Für die Behandlung der IR-Divergenzen wurde die Dipolesubtraktion verwendet wobei die Separation von kollinearen Photon–Jet-Konfigurationen mithilfe der Quark-Photon-Fragmentationsfunktion a´ la Glover / Morgan oder des Frixione-Kriteriums erfolgte. Außerdem wurden zwei experimentell motivierte Szenarien für die Behandlung von geladenen Leptonen im Endzustand berücksichtigt. In einem Fall werden kollineare Photon–Lepton-Paare zu einem Quasiteilchen zusammengefasst. Dieses Szenario entspricht der experimentellen Behandlung von Elektronen, die im Falle eines kollinearen Photons im elektromagnetischen Kalorimeter nicht von diesem getrennt werden können. Im zweiten Szenario werden Myonen und Photonen als experimentell separierbar angenommen, sodass Myon und Photon getrennt von einander im Detektor rekonstruiert werden können. Für die Berechnung der Korrekturen wurden alle Beiträge in einem fl Monte Carlo Programm 
implementiert, das neben der Berechnung des totalen Wirkungsquerschnittes auch die Erzeugung von 
Histogrammen für verschiedenste experimentell motivierte Observablen ermöglicht. Neben den typischen großen elektroschwachen Korrekturen bei hohen Transversalimpulsen sowie in Bereichen der Resonanzregion von transversaler beziehungsweise invarianter Masse zeigt sich, dass auch die photon-induzierten Korrekturen in der Größenordnung von einigen 10% bei hohen Transversalimpulsen beitragen. Die experimentelle Genauigkeit für Vγ Produktion in Run I mit 7/8 TeV am LHC lag bei etwa 10%. Aufgrund der gesteigerten Luminosität in Run II wird diese Genauigkeit noch weiter verbessert werden, sodass Korrekturen von ∼ 5% innerhalb der theoretischen Vorhersagen nicht mehr vernachlässigt werden können.
In dieser Arbeit zeigen wir Ergebnisse für den totalen Wirkungsquerschnitt am LHC für 7, 8 und 14 TeV sowie die dazugehörigen Verteilungen für 14 TeV.
KW  - Quantenchromodynamik
KW  - particle physics
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-137456
ER  - 
TY  - THES
A1  - Fuchs, Moritz Jakob
T1  - Spin dynamics in the central spin model: Application to graphene quantum dots
T1  - Spin-Dynamik im zentralen Spin-Modell: Anwendung auf Graphen-Quantenpunkte
N2  - Due to their potential application for quantum computation, quantum dots have attracted a lot of interest in recent years. In these devices single electrons can be captured, whose spin can be used to define a quantum bit (qubit). However, the information stored in these quantum bits is fragile due to the interaction of the electron spin with its environment. While many of the resulting problems have already been solved, even on the experimental side, the hyperfine interaction between the nuclear spins of the host material and the electron spin in their center remains as one of the major obstacles. As a consequence, the reduction of the number of nuclear spins is a promising way to minimize this effect. However, most quantum dots have a fixed number of nuclear spins due to the presence of group III and V elements of the periodic table in the host material. In contrast, group IV elements such as carbon allow for a variable size of the nuclear spin environment through isotopic purification. Motivated by this possibility, we theoretically investigate the physics of the central spin model in carbon based quantum dots. In particular, we focus on the consequences of a variable number of nuclear spins on the decoherence of the electron spin in graphene quantum dots.  

Since our models are, in many aspects, based upon actual experimental setups, we provide an overview of the most important achievements of spin qubits in quantum dots in the first part of this Thesis. To this end, we discuss the spin interactions in semiconductors on a rather general ground. Subsequently, we elaborate on their effect in GaAs and graphene, which can be considered as prototype materials. Moreover, we also explain how the central spin model can be described in terms of open and closed quantum systems and which theoretical tools are suited to analyze such models. 

Based on these prerequisites, we then investigate the physics of the electron spin using analytical and numerical methods. We find an intriguing thermal flip of the electron spin using standard statistical physics. Subsequently, we analyze the dynamics of the electron spin under influence of a variable number of nuclear spins. The limit of a large nuclear spin environment is investigated using the Nakajima-Zwanzig quantum master equation, which reveals a decoherence of the electron spin with a power-law decay on short timescales. Interestingly, we find a dependence of the details of this decay on the orientation of an external magnetic field with respect to the graphene plane. By restricting to a small number of nuclear spins, we are able to analyze the dynamics of the electron spin by exact diagonalization, which provides us with more insight into the microscopic details of the decoherence. In particular, we find a fast initial decay of the electron spin, which asymptotically reaches a regime governed by small fluctuations around a finite long-time average value. Finally, we analytically predict upper bounds on the size of these fluctuations in the framework of quantum thermodynamics.
N2  - Auf Grund ihres Potentials hinsichtlich der Realisierung eines Quantencomputers wurde Quantenpunkten im Laufe der letzten Jahre große Aufmerksamkeit zuteil. In diesen Halbleiterstrukturen können einzelne Elektronen kontrolliert eingeschlossen werden, deren Spin wiederum als Basis eines Quantenbits zu Speicherung von Informationen verwendet werden kann. Allerdings unterliegt das Elektron vielvältigen Wechselwirkungen mit seiner Umgebung, was oftmals zu einem sehr schnellen Verlust dieser Information führt. Eine der wichtigsten Ursachen stellt dabei die Hyperfeinwechselwirkung der Kernspins der Halbleiteratome mit dem Elektronspin  dar. 
Eine vielversprechende Möglichkeit diesen Effekt zu minimieren besteht daher in der Verringerung der Anzahl an Kernspins durch Anreicherung spinfreier Isotope. Diese Strategie kann auf Bauteile, bestehend aus Elementen der IV. Gruppe des Periodensystems wie beispielsweise Kohlenstoff, angewendet werden.
Ausgehend von dieser Möglichkeit, wird in der vorliegenden Arbeit das Verhalten des Elektronspins in (kohlenstoffbasierten) Graphenquantenpunkten im Rahmen des zentralen Spinmodells analysiert. Besonderes Augenmerk wird dabei auf die Abhängigkeit der Dekohärenzphänomene von der Kernspinzahl gelegt.

Da sich die Modelle, auf denen diese Untersuchung basiert, an experimentellen Gegebenheiten orientieren, wird zunächst ein überblick über die wichtigsten experimentellen Errungenschaften präsentiert. Neben einer allgemeinen Behandlung der Spinwechselwirkungen in Halbleitern wird dabei auch speziell auf die Eigenschaften von GaAs- und Graphenquantenpunkten eingegangen, die beide als Musterbeispiele angesehen werden können. Des Weiteren wird erläutert, wie sich das zentrale Spinmodell als offenes bzw. geschlossenes Quantensystem beschreiben lässt und mit welchen theoretischen Methoden sich diese untersuchen lassen.

Aufbauend auf diesen Erkenntnissen, wird dann das Verhalten des Elektronspins mit Hilfe analytischer und numerischer Methoden erforscht. Im Rahmen der statistischen Physik findet sich ein thermisch induzierter Wechsel der Spinorientierung. überdies wird die Zeitentwicklung des Elektronspins für unterschiedliche Kernspinzahlen analysiert. Der Limes großer Kernspinzahlen wird mit Hilfe der Nakajima-Zwanzig Mastergleichung untersucht, wobei sich für den zeitlichen Verlauf der Dekohärenz des Elektronspins ein Potenzgesetz findet. Die Details dieses Potenzgesetzes hängen dabei von der Orientierung eines äußeren Magnetfeldes ab. Eine Beschränkung auf sehr kleine Spinsysteme  ermöglicht die Anwendung von exakter Diagonalisierung, welche zusätzliche Erkenntnisse über die mikroskopischen Vorgänge, die zu Dekohärenz führen, liefert. Insbesondere ist ein schneller übergang zu einem quasi-statischen Verhalten beobachtbar, das durch kleine Fluktuationen um 
einen Langzeitmittelwert gekennzeichnet ist. Für diese Fluktuationen konnten im Rahmen der Quantenthermodynamik zusätzlich analytische Obergrenzen gefunden werden.
KW  - Elektronenspin
KW  - Quantenpunkt
KW  - Graphen
KW  - Quantum dot
KW  - Spin
KW  - Central spin
KW  - Graphene
KW  - Solid state physics
KW  - Festkörperphysik
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-136079
ER  - 
TY  - JOUR
A1  - Kümmel, Reiner
T1  - The Impact of Entropy Production and Emission Mitigation on Economic Growth
JF  - Entropy
N2  - Entropy production in industrial economies involves heat currents, driven by gradients of temperature, and particle currents, driven by specific external forces and gradients of temperature and chemical potentials. Pollution functions are constructed for the associated emissions. They reduce the output elasticities of the production factors capital, labor, and energy in the growth equation of the capital-labor-energy-creativity model, when the emissions approach their critical limits. These are drawn by, e.g., health hazards or threats to ecological and climate stability. By definition, the limits oblige the economic actors to dedicate shares of the available production factors to emission mitigation, or to adjustments to the emission-induced changes in the biosphere. Since these shares are missing for the production of the quantity of goods and services that would be available to consumers and investors without emission mitigation, the “conventional” output of the economy shrinks. The resulting losses of conventional output are estimated for two classes of scenarios: (1) energy conservation; and (2) nuclear exit and subsidies to photovoltaics. The data of the scenarios refer to Germany in the 1980s and after 11 March 2011. For the energy-conservation scenarios, a method of computing the reduction of output elasticities by emission abatement is proposed.
KW  - economic growth
KW  - entropy production
KW  - emissions
KW  - critical limits
KW  - pollution functions
KW  - output elasticities
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-163185
VL  - 18
IS  - 3
ER  - 
TY  - JOUR
T1  - The prototype detection unit of the KM3NeT detector
JF  - The European Physical Journal C
N2  - A prototype detection unit of the KM3NeT deep-sea neutrino telescope has been installed at 3500m depth 80 km offshore the Italian coast. KM3NeT in its final configuration will contain several hundreds of detection units. Each detection unit is a mechanical structure anchored to the sea floor, held vertical by a submerged buoy and supporting optical modules for the detection of Cherenkov light emitted by charged secondary particles emerging from neutrino interactions. This prototype string implements three optical modules with 31 photomultiplier tubes each. These optical modules were developed by the KM3NeT Collaboration to enhance the detection capability of neutrino interactions. The prototype detection unit was operated since its deployment in May 2014 until its decommissioning in July 2015. Reconstruction of the particle trajectories from the data requires a nanosecond accuracy in the time calibration. A procedure for relative time calibration of the photomultiplier tubes contained in each optical module is described. This procedure is based on the measured coincidences produced in the sea by the 40K background light and can easily be expanded to a detector with several thousands of optical modules. The time offsets between the different optical modules are obtained using LED nanobeacons mounted inside them. A set of data corresponding to 600 h of livetime was analysed. The results show good agreement with Monte Carlo simulations of the expected optical background and the signal from atmospheric muons. An almost background-free sample of muons was selected by filtering the time correlated signals on all the three optical modules. The zenith angle of the selected muons was reconstructed with a precision of about 3∘.
KW  - Zenith Angle
KW  - Remotely Operate Vehicle
KW  - Combinatorial Background
KW  - Time Calibration
KW  - Neutrino Telescope
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-165159
VL  - 76
IS  - 54
ER  -