Supernova-Detektion mit dem IceCube-Neutrinoteleskop

IceCube, ein Neutrinoteleskop, welches zur Zeit am Südpol aufgebaut und voraussichtlich 2011 fertiggestellt sein wird, kann galaktische Kernkollaps-Supernovae mit hoher Signifikanz und unübertroffener statistischer Genauigkeit der Neutrinolichtkurve detektieren. Derartige Supernovae werden begleitet von einem massiven Ausbruch niederenergetischer Neutrinos aller Flavour. Beim Durchfliegen des Detektormediums Eis entstehen Positronen und Elektronen, welche wiederum lokale Tscherenkowlichtschauer produzieren, die in ihrer Summe das gesamte Eis erleuchten. Ein Nachweis ist somit, trotz der Optimierung IceCubes auf hochenergetische Teilchenspuren, über eine kollektive Rauschratenerhöhung aller optischen Module möglich. Die vorwiegende Reaktion ist der inverse Betazerfall der Antielektronneutrinos, welcher über 90,% des gesamten Signals ausmacht.rnrnDiese Arbeit beschreibt die Implementierung und Funktionsweise der Supernova-Datennahme-Software sowie der Echtzeitanalyse, mit welcher die oben genannte Nachweismethode seit August 2007 realisiert ist. Die Messdaten der ersten zwei Jahre wurden ausgewertet und belegen ein extrem stabiles Verhalten des Detektors insgesamt sowie fast aller Lichtsensoren, die eine gemittelte Ausfallquote von lediglich 0,3,% aufweisen. Eine Simulation der Detektorantwort nach zwei unterschiedlichen Supernova-Modellen ergibt eine Sichtweite IceCubes, die im besten Falle bis zur 51,kpc entfernten Großen Magellanschen Wolke reicht. Leider ist der Detektor nicht in der Lage, die Deleptonisierungsspitze aufzulösen, denn Oszillationen der Neutrinoflavour innerhalb des Sterns modifizieren die Neutrinospektren ungünstig. Jedoch können modellunabhängig anhand des frühesten Signalanstiegs die inverse Massenhierarchie sowie $sin^2 2theta_{13} > 10^{-3}$ etabliert werden, falls die Entfernung zur Supernova $leq$,6,kpc beträgt. Gleiches kann durch Auswertung eines möglichen Einflusses der Erdmaterie auf die Neutrinooszillation mit Hilfe der Messung eines zweiten Neutrinodetektors erreicht werden.

Differential effect of p47phox and gp91phox deficiency on the course of Pneumococcal Meningitis.

Bacterial meningitis is a severe inflammatory disease of the central nervous system and is characterized by massive infiltration of granulocytes into the cerebrospinal fluid (CSF). To assess the role of NADPH oxidase-derived reactive oxygen species (ROS) in pneumococcal meningitis, mice deficient in either the gp91 subunit (essential for functioning of the phagocyte enzyme) or the p47 subunit (essential for functioning of homologous enzymes in nonphagocytic cells) were intracisternally infected with live Streptococcus pneumoniae, and defined disease parameters were measured during the acute stage of infection. While none of the parameters measured (including CSF bacterial titers) were significantly different in gp91(-/-) and wild-type mice, the infection in p47(-/-) mice was associated with significantly increased inflammation of the subarachnoid and ventricular space, disruption of the blood-brain barrier, and the presence of interleukin-1 beta, tumor necrosis factor alpha, and matrix metalloproteinase 9 in the cortex. These changes were associated with approximately 10-fold-higher CSF bacterial titers in p47(-/-) mice than in wild-type mice (P < 0.001). In contrast to infection with live bacteria, the inflammatory response, including CSF leukocytosis, was significantly attenuated in p47(-/-) mice (but not gp91(-/-) mice) challenged with a fixed number of heat-inactivated pneumococci. Impairment of the host defense appeared to be responsible for the higher bacterial titers in p47(-/-) mice. Therefore, these results indicate that ROS generated by a gp91-independent NADPH oxidase(s) are important for establishing an adequate inflammatory response to pneumococcal CSF infection.

Next-to-Minimal SOFTSUSY

We describe an extension to the SOFTSUSY program that provides for the calculation of the sparticle spectrum in the Next-to-Minimal Supersymmetric Standard Model (NMSSM), where a chiral superfield that is a singlet of the Standard Model gauge group is added to the Minimal Supersymmetric Standard Model (MSSM) fields. Often, a Z3 symmetry is imposed upon the model. SOFTSUSY can calculate the spectrum in this case as well as the case where general Z3 violating (denoted as ) terms are added to the soft supersymmetry breaking terms and the superpotential. The user provides a theoretical boundary condition for the couplings and mass terms of the singlet. Radiative electroweak symmetry breaking data along with electroweak and CKM matrix data are used as weak-scale boundary conditions. The renormalisation group equations are solved numerically between the weak scale and a high energy scale using a nested iterative algorithm. This paper serves as a manual to the NMSSM mode of the program, detailing the approximations and conventions used.

Neutrino physics with multi-ton scale liquid xenon detectors

We study the sensitivity of large-scale xenon detectors to low-energy solar neutrinos, to coherent neutrino-nucleus scattering and to neutrinoless double beta decay. As a concrete example, we consider the xenon part of the proposed DARWIN (Dark Matter WIMP Search with Noble Liquids) experiment. We perform detailed Monte Carlo simulations of the expected backgrounds, considering realistic energy resolutions and thresholds in the detector. In a low-energy window of 2–30 keV, where the sensitivity to solar pp and 7Be-neutrinos is highest, an integrated pp-neutrino rate of 5900 events can be reached in a fiducial mass of 14 tons of natural xenon, after 5 years of data. The pp-neutrino flux could thus be measured with a statistical uncertainty around 1%, reaching the precision of solar model predictions. These low-energy solar neutrinos will be the limiting background to the dark matter search channel for WIMP-nucleon cross sections below ~2X 10-48 cm2 and WIMP masses around 50 GeV c 2, for an assumed 99.5% rejection of electronic recoils due to elastic neutrino-electron scatters. Nuclear recoils from coherent scattering of solar neutrinos will limit the sensitivity to WIMP masses below ~6 GeV c-2 to cross sections above ~4X10-45cm2. DARWIN could reach a competitive half-life sensitivity of 5.6X1026 y to the neutrinoless double beta decay of 136Xe after 5 years of data, using 6 tons of natural xenon in the central detector region.

Decomposition studies of group 6 hexacarbonyl complexes. Part 1: Production and decomposition of Mo(CO)6 and W(CO)6

Chemical studies of superheavy elements require fast and efficient techniques, due to short half-lives and low production rates of the investigated nuclides. Here, we advocate for using a tubular flow reactor for assessing the thermal stability of the Sg carbonyl complex – Sg(CO)6. The experimental setup was tested with Mo and W carbonyl complexes, as their properties are established and supported by theoretical predictions. The suggested approach proved to be effective in discriminating between the thermal stabilities of Mo(CO)6 and W(CO)6. Therefore, an experimental verification of the predicted Sg–CO bond dissociation energy seems to be feasible by applying this technique. By investigating the effect of 104,105Mo beta-decay on the formation of 104,105Tc carbonyl complex, we estimated the lower reaction time limit for the metal carbonyl synthesis in the gas phase to be more than 100 ms. We examined further the influence of the wall material of the recoil chamber, the carrier gas composition, the gas flow rate, and the pressure on the production yield of 104Mo(CO)6, so that the future stability tests with Sg(CO)6 can be optimized accordingly.

Weak strangeness changing semi-leptonic process

We have obtained total and differential cross sections for the strangeness changing charged current weak reaction ν L + p → Λ(Σ0) + L+ using standard dipole form factors, where L stands for an electron, muon, or tau lepton, and L + stands for an positron, anti-muon or anti-tau lepton. We calculated these reactions from near threshold few hundred MeV to 8 GeV of incoming neutrino energy and obtained the contributions of the various form factors to the total and differential cross sections. We did this in support of possible experiments which might be carried out by the MINERνA collaboration at Fermilab. The calculation is phenomenologically based and makes use of SU(3) relations to obtain the standard vector current form factors and data from Λ beta decay to obtain the axial current form factor. We also made estimates for the contributions of the pseudoscalar form factor and for the F E and FS form factors to the total and differential cross sections. We discuss our results and consider under what circumstances we might extract the various form factors. In particular we wish to test the SU(3) assumptions made in determining all the form factors over a range of q2 values. Recently new form factors were obtained from recoil proton measurements in electron-proton electromagnetic scattering at Jefferson Lab. We thus calculated the contributions of the individual form factors to the total and differential cross sections for this new set of form factors. We found that the differential and total cross sections for Λ production change only slightly between the two sets of form factors but that the differential and total cross sections change substantially for Σ 0 production. We discuss the possibility of distinguishing between the two cases for the experiments planned by the MINERνA Collaboration. We also undertook the calculation for the inverse reaction e − + p → Λ + νe for a polarized outgoing Λ which might be performed at Jefferson Lab, and provided additional analysis of the contributions of the individual form factors to the differential cross sections for this case. ^

Analysis of Cosmogenic Impurities in Tellurium and Development of Tellurium Loading for the SNO+ Experiment

For the SNO+ neutrinoless double beta decay search, various backgrounds, ranging from impurities present naturally to those produced cosmogenically, must be understood and reduced. Cosmogenic backgrounds are particularly difficult to reduce as they are continually regenerated while exposed to high energy cosmic rays. To reduce these cosmogenics as much as possible the tellurium used for the neutrinoless double beta decay search will be purified underground. An analysis of the purification factors achievable for insoluble cosmogenic impurities found a reduction factor of $>$20.4 at 50\% C.L.. During the purification process the tellurium will come into contact with ultra pure water and nitric acid. These liquids both carry some cosmogenic impurities with them that could be potentially transferred to the tellurium. A conservative limit is set at $<$18 events in the SNO+ region of interest (ROI) per year as a result of contaminants from these liquids. In addition to cosmogenics brought underground, muons can produce radioactive isotopes while the tellurium is stored underground. A study on the rate at which muons produce these backgrounds finds an additional 1 event per year. In order to load the tellurium into the detector, it will be combined with 1,2-butanediol to form an organometallic complex. The complex was found to have minimal effect on the SNO+ acrylic vessel for 154 years.

Time-resolved fluorescence observation of di-tyrosine formation in horseradish peroxidase upon ultrasound treatment leading to enzyme inactivation

The application of ultrasound to a solution can induce cavitional phenomena and generate high localised temperatures and pressures. These are dependent of the frequency used and have enabled ultrasound application in areas such as synthetic, green and food chemistry. High frequency (100 kHz to 1 MHz) in particular is promising in food chemistry as a means to inactivate enzymes, replacing the need to use periods of high temperature. A plant enzyme, horseradish peroxidase, was studied using time-resolved fluorescence techniques as a means to assess the effect of high frequency (378 kHz and 583 kHz) ultrasound treatment at equivalent acoustic powers. This uncovered the fluorescence emission from a newly formed species, attributed to the formation of di-tyrosine within the horseradish peroxidase structure caused by auto-oxidation, and linked to enzyme inactivation.

Evaluation of Th and U contamination in the CUORE experiment using a delayed coincidence analysis

The discovery of the neutrino mass is a direct evidence of new physics. Several questions arise from this observation, regarding the mechanism originating the neutrino masses and their hierarchy, the violation of lepton number conservation and the generation of the baryon asymmetry. These questions can be addressed by the experimental search for neutrinoless double beta (0\nu\beta\beta) decay, a nuclear decay consisting of two simultaneous beta emissions without the emission of two antineutrinos. 0\nu\beta\beta decay is possible only if neutrinos are identical to antineutrinos, namely if they are Majorana particles. Several experiments are searching for 0\nu\beta\beta decay. Among these, CUORE is employing 130Te embedded in TeO_2 bolometric crystals. It needs to have an accurate understanding of the background contribution in the energy region around the Q-value of 130Te. One of the main contributions is given by particles from the decay chains of contaminating nuclei (232Th, 235-238U) present in the active crystals or in the support structure. This thesis uses the 1 ton yr CUORE data to study these contamination by looking for events belonging to sub-chains of the Th and U decay chains and reconstructing their energy and time difference distributions in a delayed coincidence analysis. These results in combination with studies on the simulated data are then used to evaluate the contaminations. This is the first time this analysis is applied to the CUORE data and this thesis highlights the feasibility of it while providing a starting point for further studies. A part of the obtained results agrees with ones from previous analysis, demonstrating that delayed coincidence searches might improve the understanding of the CUORE experiment background. This kind of delayed coincidence analysis can also be reused in the future once the, CUORE upgrade, CUPID data will be ready to be analyzed, with the aim of improving the sensitivity to the 0\nu\beta\beta decay of 100Mo.

Fermion masses, leptogenesis and gravitational waves in SO(10)

Grand Unification Theories (GUTs) predict the unification of three of the fundamental forces and are a possible extension of the Standard Model, some of them predict neutrino mass and baryon asymmetry. We consider a minimal non-supersymmetric $SO(10)$ GUT model that can reproduce the observed fermionic masses and mixing parameters of the Standard Model. We calculate the scales of spontaneous symmetry breaking from the GUT to the Standard Model gauge group using two-loop renormalisation group equations. This procedure determines the proton decay rate and the scale of $U(1)_{B-L}$ breaking, which generates cosmic strings, and the right-handed neutrino mass scales. Consequently, the regions of parameter space where thermal leptogenesis is viable are identified and correlated with the fermion masses and mixing, the neutrinoless double beta decay rate, the proton decay rate, and the gravitational wave signal resulting from the network of cosmic strings. We demonstrate that this framework, which can explain the Standard Model fermion masses and mixing and the observed baryon asymmetry, will be highly constrained by the next generation of gravitational wave detectors and neutrino oscillation experiments which will also constrain the proton lifetime

Constraining the absolute neutrino mass scale and Majorana CP violating phases by future 0νββ decay experiments

Assuming that neutrinos are Majorana particles, in a three-generation framework, current and future neutrino oscillation experiments can determine six out of the nine parameters which fully describe the structure of the neutrino mass matrix. We try to clarify the interplay among the remaining parameters, the absolute neutrino mass scale and two CP violating Majorana phases, and how they can be accessed by future neutrinoless double beta (0vυββ) decay experiments, for the normal as well as for the inverted order of the neutrino mass spectrum. Assuming the oscillation parameters to be in the range presently allowed by atmospheric, solar, reactor, and accelerator neutrino experiments, we quantitatively estimate the bounds on m 0, the lightest neutrino mass, that can be inferred if the next generation 0υββ decay experiments can probe the effective Majorana mass (m ee) down to ∼1 meV. In this context we conclude that in the case that neutrinos are Majorana particles, (a) if m 0≳300 meV, i.e., within the range directly attainable by future laboratory experiments as well as astrophysical observations, then m ee≳30 meV must be observed, (b) if m 0 ≤ 300 meV, results from future 0υββ decay experiments combined with stringent bounds on the neutrino oscillation parameters, especially the solar ones, will place much stronger limits on the allowed values of m 0 than these direct experiments. For instance, if a positive signal is observed around m ee = 10 meV, we estimate 3≲m 0/meV≲65 at 95% C.L.; on the other hand, if no signal is observed down to m ee = 10 meV, then m 0≲55 meV at 95% C.L.

Polymer matrix sensitizing effect on photoluminescence properties of Eu(3+)-beta-diketonate complex doped into poly-beta-hydroxybutyrate (PHB) in film form

In this work is reported the sensitization effect by polymer matrices on the photoluminescence properties of diaquatris(thenoyltrifluoroacetonate)europium(III), [Eu(tta)(3)(H(2)O)(2)], doped into poly-beta-hydroxybutyrate (PHB) with doping percentage at 1, 3, 5, 7 and 10% (mass) in film form. TGA results indicated that the Eu(3+) complex precursor was immobilized in the polymer matrix by the interaction between the Eu(3+) complex and the oxygen atoms of the PHB polymer when the rare earth complex was incorporated in the polymeric host. The thermal behaviour of these luminescent systems is similar to that of the undoped polymer, however, the T(onset) temperature of decomposition decreases with increase of the complex doping concentration. The emission spectra of the Eu(3+) complex doped PHB films recorded at 298 K exhibited the five characteristic bands arising from the (5)D(0) -> (7)F(J) intraconfigurational transitions (J = 0-4). The fact that the quantum efficiencies eta of the doped film increased significantly revealed that the polymer matrix acts as an efficient co-sensitizer for Eu(3+) luminescent centres and therefore enhances the quantum efficiency of the emitter (5)D(0) level. The luminescence intensity decreases, however, with increasing precursor concentration in the doped polymer to greater than 5% where a saturation effect is observed at this specific doping percentage, indicating that changes in the polymeric matrix improve the absorption property of the film, consequently quenching the luminescent effect.

Decay chain differential equations: Solution through matrix algebra

A matricial method to solve the decay chain differential equations system is presented. The quantity of each nuclide in the chain at a time t may be evaluated by analytical expressions obtained in a simple way using recurrence relations. This method may be applied to problems of radioactive buildup and decay and can be easily implemented computationally. (C) 2009 Elsevier B.V. All rights reserved.

WNT-5A, but not matrix metalloproteinase 3 or beta-catenin protein, expression is related to early stages of lip carcinogenesis

Background: Oncogenic Wnt/beta-catenin signaling occurs in numerous types of cancers, but little is known about the role of the Wnt protein family member, WNT-5A, in lip carcinogenesis. The aim of this study was to investigate WNT-5A, beta-catenin, and matrix metalloproteinase (MMP)-3 protein expression in actinic cheilitis (AC), and lip squamous cell carcinoma (LSCC). Methods: Twenty-one cases of AC, and fifty-one cases of LSCC were analyzed, with normal lip mucosa used as a control. Qualitative and semi-quantitative analyses of WNT-5A, beta-catenin, and MMP-3 immunostaining pattern and cellular distribution were performed. Results: WNT-5A was observed in more than 50% of the cells, scattered in all layers of AC, in contrast to the absence of immunostaining in normal lip mucosa. AC presented a higher level of WNT-5A expression than LSCC (P = 0.0289, Fisher test), while MMP-3 immunoexpression was statistically more significant in LSCC than in AC (P = 0.0285, Fisher test). Immunolabeling of beta-catenin protein was differentially distributed between samples; the majority of AC cases (61.90%) demonstrated a membranous-cytoplasmic pattern, while a considerable number of LSCC cases (29.41%) revealed a cytoplasmic pattern, instead of the usual membranous pattern. Conclusions: The present results suggest that WNT-5A may be an important marker during initial events of AC malignant transformation, in which non-canonical and canonical Wnt/beta-catenin signaling pathways could be involved. Additionally, WNT-5A might recruit other events in LSCC, such as MMP-3 protein synthesis, as its presence is increased in established malignant processes without beta-catenin dependency.

Calculation of product state distributions from resonance decay via Lanczos subspace filter diagonalization: Application to HO2

Resonance phenomena associated with the unimolecular dissociation of HO2 have been investigated quantum-mechanically by the Lanczos homogeneous filter diagonalization (LHFD) method. The calculated resonance energies, rates (widths), and product state distributions are compared to results from an autocorrelation function-based filter diagonalization (ACFFD) method. For calculating resonance wave functions via ACFFD, an analytical expression for the expansion coefficients of the modified Chebyshev polynomials is introduced. Both dissociation rates and product state distributions of O-2 show strong fluctuations, indicating the dissociation of HO2 is essentially irregular. (C) 2001 American Institute of Physics.