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[en] The human identification process represents one of the most relevant aspects of the forensic sciences field. Few studies related to sex dimorphism have evaluated the accuracy of linear measurements of frontal and maxillary sinuses on multislice computed tomography (MCT). This investigation aimed to: (1) evaluate parameters of accuracy in sex estimation of maxillary and frontal sinuses on MCT of Brazilian adult individuals; (2) develop and cross-validate a new formula for discriminating males and females. Two-phase cross-sectional research was conducted with a statistically estimated sample of 140 MCTs: phase 1) development of a formula based on both sinuses (50 males and 50 females); phase 2) validation study (20 males and 20 females). Frontal and maxillary sinuses linear measurements (height, width, and diameter) were assessed using the RadiAnt DICOM software. Based on a multivariate statistical approach, a new formula combining both paranasal sinuses was developed and further validated. Receiver operating characteristic (ROC) curves, the area under the curve (AUC), sensitivity, specificity, positive and negative predictive values, accuracy, and likelihood ratio were obtained. Also, the influence of age was evaluated by subgroup statistical analysis. Men showed higher mean values of width, height, and diameter of the studied paranasal sinuses (p<0.05). The maxillary sinuses were a better predictor of sex estimation than frontal sinus (accuracy between 61-74% and 58-69%, respectively). The highest accuracy was found with the distance between the right and left maxillary sinuses (74%).The formula for sex estimation showed a sensitivity of 80%, specificity of 95.5%, and an accuracy of 87.5%. In individuals aged > 30 years, there was a 63.1% reduction in predictive values for sex estimation. Frontal and maxillary sinuses measurements were adequate predictors for sexual dimorphism in a Brazilian sample. Both paranasal sinuses showed a better estimation of males, and the most significant accuracy occurred with maxillary sinuses. High precision was found with the distance between the right and left maxillary sinuses. The multivariate statistics-based formula provided a better precision in discriminating males and females. (author)
[en] In this work, a search for heavy pseudoscalar and scalar (A/H) Higgs bosons decaying to top-anti-top quark pairs (t) and a measurement of top quark polarization and t spin correlation are presented, performed using 35.9 /fb of data recorded by the CMS experiment in 2016. The dileptonic t final state is investigated in both analyses. The A/H Higgs boson search exploits the 2-dimensional spectrum of t invariant mass and an angular observable sensitive to both the spin and parity of the t system. The search probes mass and relative decay width ranges of 400 - 750 GeV and 0.5% - 50%, respectively. An excess consistent with the A(400 GeV, 5%) signal hypothesis is observed with a local significance of 4 in the dileptonic channel and 3.7 in the combination of dileptonic and semileptonic channels. The global significance of such an excess is found to be 2. Exclusion regions on the coupling modifier of the A/H to top quarks are derived. These results are converted into exclusion regions in the context of a supersymmetric model, the hMSSM, and are given in the parameter space m-tan . In the spin correlation measurement, the distributions of all independent observables that are directly sensitive to the elements of top quark polarization vector and t spin density matrix are measured, unfolded to the level of generated partons, and extrapolated to the full phase space. In addition, the distributions of two angles between the charged leptons in the laboratory frame, which are, however, only indirectly sensitive to the t spin correlations but can be extracted with excellent experimental resolution, are measured. An overall good agreement with the standard model is observed. However, there is some tension between the data and predictions in the distribution of the azimuthal gap between the charged leptons in the laboratory frame. The measurements are used to constrain anomalous contributions within an Effective Field Theory framework.
[en] In this thesis, the first experimental determination of the running of the top quarkmass is presented. The running is extracted from a measurement of the differentialtop quark-antiquark () production cross section as a function of the invariant mass of the system, m. The analysis is performed using proton-proton collision data recorded by the CMS detector at the CERN LHC in 2016, corresponding to an integrated luminosity of 35.9 fb. Candidate events are selected in the final state with an electron and a muon of opposite charge, and the differential cross section dσ/dm is determined at the parton level by means of a maximum-likelihood fit to multidifferential final-state distributions. The value of the top quark mass in the modified minimal subtraction () renormalization scheme, m(μ), is determined as a function of the scale μ=m by comparing the measured dσ/dm to theoretical predictions at next-to-leading order, and the resulting scale dependence is interpreted as the running of the top quark mass. The observed running is found to be compatible with the one-loop solution of the corresponding renormalization group equation, up to a scale of the order of 1 TeV.
[en] The thorium isotope Th has the isomeric state with the lowest nuclear excitation known and is thereby a good candidate for investigating the stability of universal constants and a new generation of time-standards. In the framework of this thesis the uncertainty of the experimental value of the isomeric energy has been further improved to reduce the wavelength range that needs to be scanned in a laserdriven excitation and to speed up the lengthy search due to the small linewidth. A high-resolution microcalorimeter-array of maXs30-type based on metallic magnetic calorimeters (MMC) has been designed, fabricated in the cleanroom and used to measure the gamma-spectrum of Th. An MMC consists of a particle absorber and a paramagnetic sensor. A change of temperature caused by an absorbed photon is converted to a change of magnetization by the paramagnetic material and read out by a SQUID. This detector shows excellent linearity and energy resolutions of 7.9 eV (FWHM) at small energies and 9.8 eV at 60 keV, corresponding to a resolving power above 6000. The gamma-spectrum of excited Th is produced by the -decay of a chemically purified U-source. On three different ways the isomeric energy could be extracted consistently from the spectrum resulting in E = (8.09 0.13 (stat) (syst)) eV.
[en] Mixed convection occurs in a Passive Cooling System (PCS), Small Modular Reactors (SMR), Very High Temperature Gas-cooled Reactor (VHTGR) and Super-Critical Water Reactor (SCWR) due to buoyancy influence. This can lead to local impairment of the cooling performance and affect the heat transfer performance. Mixed convection is the flow phenomenon that occurs when the flow is driven by both forced convection and natural convection in similar magnitudes. Depending on the direction of forced convection, it is divided into buoyancy-aided flow and buoyancy-opposed flow. In laminar mixed convection, buoyancy-aided flow shows enhanced heat transfer compared to the pure forced convection due to the velocity increase by the addition of buoyancy force. However, in turbulent mixed convection, for small buoyance, buoyancy-aided flow shows impaired heat transfer compared with that of forced convection under the same flow condition. This is caused by the reduction of the turbulence production by decreased turbulent shear stress near the heated wall. When buoyance increases, the mixed convection heat transfer recovers and then enhances compared with the forced convection of similar flow condition. The behavior of mixed convection heat transfer is non-monotonous, depending on the forced flow direction, the flow conditions, and the geometry of the system. The existing correlations for turbulent mixed convection heat transfer are not applicable to other systems as they have been developed to fit their specific systems. Therefore, it is necessary to develop a more generalized heat transfer correlation considering the height of the system through the phenomenological analysis of turbulent mixed convection. In this study, the buoyancy-aided turbulent mixed convection experiments were performed on the circular heating and non-circular heating conditions. To achieve high buoyancy, mass transfer experiments utilizing the copper sulfate-sulfuric acid electroplating system, were performed replacing heat transfer ones based on the analogy concept. The local average heat transfers were measured varying the axial position (χ), the total height of the heated wall (H), the hydraulic diameter (D) and the flow rate (ν). In order to compare the mixed convection heat transfer with that of the forced convection including the thermal entry effect, the forced convection experiments were performed and the modified turbulent forced convection correlation was developed based on the correlation of Gnelinski and Petukhov et al. The local heat transfer of the mixed flow were lower than that of the forced convection and behaved non-monotonously along the axial position due to the buoyancy influences. This is the result of the interaction between the natural convection flow development near the wall and forced convection in the core region of the channel. As the total height of the heated wall increases, the local heat transfer decreases due to the influence of the system buoyancy. The local heat transfer was increasingly impaired with the decreased hydraulic diameter. Because the magnitude of the buoyancy influence increases as the heated perimeter increases with respect to the flow surface area. The double dip behavior was observed: one from deteriorated regime and the other one from transition flow regime. The Particle Image Velocimetry (PIV) measurements of the velocity and turbulent shear stress backed up these observations. Non-monotonous behaviors of the mixed convection along x/D were discussed. We observed that the thickness of the viscous sublayer increased and distorted velocity profile with the buoyancy effect. We concluded that the mixed convection heat transfer is affected by the magnitude of turbulent shear stress at the edge of the viscous sublayer and buffer layer. The buoyancy coefficient was derived through the scale analysis and through the comparisons of the results of the existing studies and the current experiments. The turbulent mixed convection heat transfer correlations were developed for both non-circular heating and circular heating conditions by considering the buoyant flow development (χ/D), heated perimeter to flow surface area (D/H), system buoyancy ((H-χ)/D). These correlations were compared with the experimental results of other studies and are more general, which expand the applicability of the correlations to other systems with different heating length and can contribute to enhancement of the fundamental understanding of the mixed convection phenomena and detailed analysis on the cooling performance analysis and safety system design
[en] Natural essential oils are complex mixtures containing several compounds of structural similarity. They are well known for their wide range of applications in different areas, from medicine to cosmetics. One of the conventional methods for their quantitative analysis is gas chromatography (GC). Despite the numerous advantages of GC as an analytical tool, some aspects such as structure determination cannot be addressed with it. Another technique which is applicable to the volatile essential oil components is rotational spectroscopy. It is a powerful method for the structure determination not only of the respective compounds, but also of their different isomers and conformers. Rotational spectroscopy thus complements the information obtained with GC, which is necessary for a comprehensive study on the molecular systems of interest. In the first part of this thesis, some of the main constituents of peppermint and thyme oils were analyzed with rotational spectroscopy. Structure determination of several oil components including menthol, thymol, linalool, and pulegone was performed. The internal dynamics of trans-thymol-B, linalool, pulegone, and menthyl acetate, resulting from the internal rotation of their methyl groups were studied. The conformational landscape of menthyl acetate was characterized both experimentally and computationally. All these key points help to better understand the functionality of the chemical substances discussed here, and their mode of interaction in our body. Additionally, a semi-quantitative analysis of thyme oil was performed. The results were compared to the GC study for benchmarking purposes, showing a good agreement. Many of the essential oil constituents are chiral. Chirality is of utmost importance in the biological context. There is a high demand for reliable methods for a detailed characterization of chiral molecules. Recent developments in rotational spectroscopy have enabled the exploration of molecules in a chirality-sensitive way by applying the microwave three-wave mixing (M3WM) technique. The M3WM makes use of the advantages of rotational spectroscopy such as conformer selectivity and mixture compatibility. It was successfully applied in the scope of this thesis to differentiate between the enantiomers of some essential oil constituents. The M3WM was recently extended to allow coherent population transfer (CPT) of the enantiomers to rotational states of choice. This approach is discussed in the second part of the present work. It may pave the way for enantioseparation in future experiments. Finally, M3WM and CPT were combined in the experiment to manipulate the chiral conformers of a molecule, which has no stereogenic center (cyclohexylmethanol). Such a procedure significantly widens the range of molecular systems available for chiral analysis with rotational spectroscopy.
[en] In this thesis measurements of the t pair production at the very high transverse momentum are presented. When a top quark is produced with very high momentum the decay products are collimated in the direction of the quark, and they can be clustered within a single large cone size jet. The decay products of top quarks with transverse momentum larger than 400 GeV are likely having this boosted configuration. A definition of a particle-level top jet is developed which is independent of the partonic configuration. The measurements are performed with proton-proton collision data collected by the CMS experiment at the LHC, at the center of mass energy of = 13 TeV and they are presented differentially in the transverse momentum of the top jets and differentially in the azimuthal angle between the two top-jets. The results are compared to theory predictions provided from different Monte Carlo event generators: i.e POWHEG+PYTHIA8, POWHEG+HERWIGpp and aMC@NLO+PYTHIA8.
[en] The Standard Model of particle physics is a very successful theory, but it leaves some open questions. Especially the topic of dark matter is a very active field of research and the discovery of dark matter candidates might be accessible to modern collider experiments. Answering open questions of the Standard Model is one of the greater goals of this work. The dark matter candidates might interact with the recently discovered Higgs boson and would appear invisible to a particle detector. This motivates a search for invisible decays of the Higgs boson produced in vector-boson fusion. The search is looking for a pair of wellseparated, highly energetic jets and missing transverse energy in the final state. The analysisuses 36.1 fb of proton–proton collision data recorded at a centre-of-mass energy of 13 TeV in 2015 and 2016 with the ATLAS experiment at the LHC. The main backgrounds are leptonically decaying vector bosons. These backgrounds are constrained in dedicated data control regions. The multijet background is small, since it can only result from mismeasurements of the jet transverse momentum, but it is challenging to quantify. The jet response is a measure for the mismeasurement of jet transverse momenta. To study how well it is simulated in areas of extreme mismeasurements the non-Gaussian tails of these distributions are quantified in a comparison between data and simulation. This is achieved by modelling the Gaussian core with fits. In order to see the effect in data the momentum balance of jet pairs is considered by using an extrapolation to pure dijet events. The effort is undertaken with a new jet definition, particle flow jets, as well as topocluster jets. For both of them simulation and data are in good agreement. This leads to systematic uncertainties small enough to have a negligible impact on the analysis. The systematic uncertainty resulting from the jet energy resolution is one of the main limitations to the sensitivity of the search. This is addressed with the global sequential calibration (GSC), a simulation-driven method that removes the dependencies of jet momenta on a selection of detector variables in order to improve the jet resolution. The calibration leads to a jet resolution improvement of up to 20%. The GSC is fully derived for particle flow jets for the first time, allowing performance comparisons between different kinds of jet reconstruction algorithms. The search is able to derive a new observed (expected) limit on the Higgs to invisible branching fraction of 0.37 (0.28) at 95% confidence level. The results are also interpreted considering a Higgs portal model, treating the invisible decay products as dark matter candidates. The resulting limits on the cross-section for the DM candidate to interact with an atomic nucleus is between 10 cm and 10 cm at 90% confidence level depending on the DM mass and spin..
[en] The inference of massive neutrino states through the observation of flavor oscillations boosted the importance of direct and indirect mass searches, including the search for the hypothesized neutrinoless double beta decay (0νββ-decay). Nowadays, the search for this ultra-rare nuclear transition is one of the most active research fields at the intersection of nuclear, particle and astroparticle physics. Its main and evident feature is the explicit violation of the total lepton number, which is an accidentally conserved quantity in the Standard Model of particle physics, and would prove the Majorana nature of neutrinos. This, in turn, would support the theoretical explanation of the origin of the observed baryon asymmetry in the universe through the process of leptogenisis and could shed light on the role of neutrinos in the early universe’s structure formation. For the theoretical description of the 0νββ-decay, nuclear structure effects play an important role as they may affect considerably the decay rate. These nuclear effects are summarized as the nuclear matrix elements (NMEs), containing information about the initial and final states of the involved atomic nuclei and the decay mechanism. Under the assumption of light Majorana neutrino exchange, the inverse half-life is proportional to the effective Majorana neutrino mass, a kinematic phase-space factor, the involved NMEs and the fourth power of the weak axial-vector coupling g. The search for the 0νββ-decay is driven by experiments and an accurate description of the nuclear structure effects is essential to estimate the required sensitivity to cover a certain mass range. In order to match theoretical calculations and the results of β-decay and ββ-decay studies, there is a scientific discussion regarding quenching effects of g in nuclear media. Different methods are being investigated to determine an effective g at the energy scale of nuclear transitions. One of those recently proposed methods exploits the dependency of the spectrum-shape of highly forbidden β-decays on g. An ideal candidate for such an investigation is the fourfold forbidden non-unique β-decay of Cd, which is the most prominent signal in the current stage of the COBRA experiment searching for 0νββ-decays with cadmium zinc telluride (CZT) solid state detectors. The detector material CZT acts as a semiconductor at room temperature and contains intrinsically several candidates for rare nuclear transitions. The experiment is located at the LNGS underground facility in Italy, which is shielded against cosmic rays by a mean rock coverage of about 1400 m. In the present demonstrator phase, it consists of 64 coplanar grid (CPG) detectors that are arranged in four layers of 4 4 crystals. In the scope of this thesis, conventional and novel prototype CPG-CZT detectors, which are the basis for an anticipated large-scale experiment, are characterized by evaluating homogeneous and localized γ-ray irradiation measurements. Moreover, a novel pulse-shape discrimination (PSD) technique is established, optimized and applied in the analysis of the physics data obtained with the demonstrator array. The PSD optimization is complemented by dedicated laboratory measurements with the aim to create a pulseshape library of signal-like single-site events and high-energy cosmic muon interactions for which an analytic reconstruction model has been developed. For the first time, the COBRA demonstrator’s full exposure from Sept.'11 to Nov.'19 is analyzed, including a detailed background characterization as well as an automatized data partitioning to identify periods with increased backgrounds. The main subject is the study of the Cd β-decay’s spectrum-shape to address the quenching of g in lowmomentum exchange nuclear processes. The analysis of the experimental data is carried out in the context of three nuclear frameworks and confirms the idea of a significantly quenched g. Furthermore, the data are analyzed with respect to the 2νββ-decay of Cd and the long-lived α-decay of Pt as a localized contaminant in the CZT detectors’ electrode metalization. Finally, the prospects of a search for excited state transitions of the ββ-nuclides Cd and Te are studied with elaborate Monte-Carlo simulations. The analysis section is concluded with an estimate of the achievable 0νββ-decay half-life sensitivity for multiple ββ-nuclides given the full exposure of the COBRA demonstrator and the recently achieved upgrade to the COBRA eXtended DEMonstrator (XDEM).
[en] In this work the calculation of the resonance’s decay parameters with N = 2 + 1 + 1 flavour lattice QCD is presented. The calculation is performed based on gauge configuration ensembles produced by the ETM collaboration which were generated with three different lattice spacing values and pion masses ranging from 230 MeV to 500 MeV. The calculation of resonance parameters with Lattice QCD requires correlation functions of all relevant decay channels in multiple moving reference frames. In this work operators resembling a meson as well as a -system are used. The boost to moving frames breaks rotational symmetry and thereby causes a level splitting. Operators which transform like basis states of the reduced symmetry groups’ irreducible representations are constructed to determine each energy level individually. Aided by the stochastic Laplacian Heaviside method correlation functions are calculated for all lattice momenta up to (0, 0, 2) and all irreducible representations that emerge. From these correlation functions energy levels are determined under consideration of systematic error sources. Most notably the effect of thermal pollutions and bias from fit range selection are taken into account. By applying the Lüscher method the energy spectra are translated into phase shift curves on each ensemble separately. From a Breit-Wigner fit to the phase shift curves the meson mass and width on all ensembles are determined. The results are fed into a combined fit of mass and width and extrapolated to the chiral and continuum limit. The main result of this thesis are the continuum extrapolated values of M and at the physical point which were determined to M = 769(19) MeV, = 129(7) MeV. Lattice artefacts could not be resolved within the statistical uncertainties of this work. While the -meson massis in very good agreement with experiment the corresponding decay width differs by about two standard deviations from its experimental counterpart. The results of this thesis were pre-published in .