1. Gauge group topology of 8D Chaudhuri-Hockney-Lykken vacuaMirjam Cvetič, Markus Dierigl, Ling Lin, Hao Y. Zhang, 2021, original scientific article Abstract: Compactifications of the Chaudhuri-Hockney-Lykken (CHL) string to eight dimensions can be characterized by embeddings of root lattices into the rank 12 momentum lattice ΛM, the so-called Mikhailov lattice. Based on these data, we devise a method to determine the global gauge group structure including all Uð1Þ factors. The key observation is that, while the physical states correspond to vectors in the momentum lattice, the gauge group topology is encoded in its dual. Interpreting a nontrivial π1ðGÞ ≡ Z for the non-Abelian gauge group G as having gauged a Z 1-form symmetry, we also prove that all CHL gauge groups are free of a certain anomaly [1] that would obstruct this gauging. We verify this by explicitly computing Z for all 8D CHL vacua with rankðGÞ ¼ 10. Since our method applies also to T2 compactifications of heterotic strings, we further establish a map that determines any CHL gauge group topology from that of a “parent” heterotic model. Keywords: astrophysics, compactification, string dualities, string and branes, discrete symmetries, symmetries, gauge symmetries Published in DKUM: 13.10.2023; Views: 402; Downloads: 19 Full text (356,95 KB) This document has many files! More... |
2. Search for ▫$Z^\prime \to \mu^+ \mu^-$▫ in the ▫$L_\mu - L_\tau$▫ gauge-symmetric model at BelleT. Czank, Karol Adamczyk, Jyoti Prakash Biswal, Marko Bračko, Boštjan Golob, Samo Korpar, Peter Križan, Manca Mrvar, Rok Pestotnik, Tomaž Podobnik, Samo Stanič, Marko Starič, Luka Šantelj, 2022, original scientific article Abstract: We search for a new gauge boson Z′ that couples only to heavy leptons and their corresponding neutrinos in the process e+e−→Z′(→μ+μ−)μ+μ−, using a 643 fb−1 data sample collected by the Belle experiment at or near the Υ(1S,2S,3S,4S,5S) resonances at the KEKB collider. While previous searches for Z′ performed a data-based estimation of the initial state radiation effect, our search for the Z′ is the first to include effects due to initial state radiation in the signal simulated samples that were used in estimating the detection efficiency. No signal is observed in the Z′ mass range of 0.212–10 GeV/c2, and we set an upper limit on the coupling strength, g′, constraining the possible Z′ contribution to the anomalous magnetic dipole moment of the muon. Keywords: Extensions of gauge sector, leptonic, semileptonic & radiative decays Published in DKUM: 25.09.2023; Views: 455; Downloads: 26 Full text (725,14 KB) This document has many files! More... |
3. Flavor symmetries and automatic enhancement in the 6D supergravity swamplandMirjam Cvetič, Ling Lin, Andrew P. Turner, 2022, original scientific article Abstract: We argue for the quantum-gravitational inconsistency of certain 6D N ¼ ð1; 0Þ supergravity theories, whose anomaly-free gauge algebra g and hypermultiplet spectrum M were observed by Raghuram et al. [J. High Energy Phys. 07 (2021) 048] to be realizable only as part of a larger gauge sector ðg0 ⊃ g; M0 ⊃ MÞ in F-theory. To detach any reference to a string theoretic method of construction, we utilize flavor symmetries to provide compelling reasons why the vast majority of such ðg; MÞ theories are not compatible with quantum gravity constraints, and how the “automatic enhancement” to ðg0 ; M0 Þ remedies this. In the first class of models, with g0 ¼ g ⊕ h, we show that there exists an unbroken flavor symmetry h acting on the matter M, which, if ungauged, would violate the no-global-symmetries hypothesis. This argument also applies to 1-form center symmetries, which govern the gauge group topology and massive states in representations different from those of massless states. In a second class, we find that g is incompatible with the flavor symmetry of certain supersymmetric strings that must exist by the completeness hypothesis. Keywords: supergravity theories, supersymmetric strings, quantum gravity constraints, Gauge theories, Higher-dimensional field theories, strings & branes, supergravity, symmetries Published in DKUM: 25.09.2023; Views: 258; Downloads: 8 Full text (317,88 KB) This document has many files! More... |
4. All eight- and nine-dimensional string vacua from junctionsMirjam Cvetič, Markus Dierigl, Ling Lin, Hao Y. Zhang, 2022, original scientific article Abstract: String and 5-brane junctions are shown to succinctly classify all known 8D N ¼ 1 string vacua. This requires an extension of the description for ordinary ½p; q-7-branes to consistently include O7þ planes, which then naturally encodes the dynamics of spn gauge algebras, including their p-form center symmetries. Central to this analysis are loop junctions, i.e., strings/5-branes which encircle stacks of 7-branes and O7þs. Loop junctions further signal the appearance of affine symmetries of emergent 9D descriptions at the 8D moduli space’s boundaries. Such limits reproduce all 9D string vacua, including the two disconnected rank (1,1) moduli components. Keywords: 9D string vacua, 8D string vacua, anomalies, M-theory, Non-Abelian gauge theories, quantum gravity, string dualities, strings & branes, supergravity, Gauge symmetries Published in DKUM: 22.09.2023; Views: 286; Downloads: 21 Full text (1,09 MB) This document has many files! More... |
5. Processing of signals produced by strain gauges in testing measurements of the bridgesBoštjan Kovačič, Rok Kamnik, Andrej Štrukelj, Nikolai Ivanovich Vatin, 2015, published scientific conference contribution Abstract: Practical example of signal processing from strain gauge, inductive transducer and total station measurements are used to illustrate the features of the bridge load testing measurements. FFT provides accurate representation of physical behavior for static and dynamic signals obtained when loading the bridge. As a reference measurement the signal from inductive transducer was taken. A static part of the load test was also geodetically measured and theoretically calculated. The results are comparable. Keywords: bridges, measurements, strain gauge, load test, deformation, strain, signal processing Published in DKUM: 12.07.2023; Views: 445; Downloads: 24 Full text (500,43 KB) This document has many files! More... |
6. The different methods of displacement monitoring at loading tests of bridges or different structuresBoštjan Kovačič, Rok Kamnik, Andrii Bieliatynskyi, 2016, published scientific conference contribution Abstract: By measuring the displacements and deformations at different structures we deal in the Faculty of Civil Engineering, transportation Engineering and Architecture in University of Maribor for about 20 years. At that time we measured over 600 structures. Most loading tests of bridges and Viaducts were made. The measurements of movements needed to be as precise and accurate as possible. To do that laboratory test of instruments were made to see which instrument gives us reliable results. Displacements can be determined by geodetic and physical methods, depends of the construction. The use of geodetic methods are still preferable. In the paper the measurements with the total station, the level and rotation level, photogrammetry and solutions on the field by physical methods with inductive transducers are presented. We need to measure displacements as quick as possible but efficiently because we can not repeat the measurements under the same conditions. Also the surveying on the bridge and in the lab with the comparison of methods is presented under the different hard terrain conditions - water beneath the construction, big height of the structure, unapproachability, large span structures. Keywords: bridges, measurements, strain gauge, load test, deformation, strain, signal processing Published in DKUM: 02.08.2017; Views: 1262; Downloads: 334 Full text (3,15 MB) This document has many files! More... |
7. Black hole thermodynamics from a variational principle: asymptotically conical backgroundsSong-ok An, Mirjam Cvetič, Ioannis Papadimitriou, 2016, original scientific article Abstract: The variational problem of gravity theories is directly related to black hole thermodynamics. For asymptotically locally AdS backgrounds it is known that holographic renormalization results in a variational principle in terms of equivalence classes of boundary data under the local asymptotic symmetries of the theory, which automatically leads to finite conserved charges satisfying the first law of thermodynamics. We show that this connection holds well beyond asymptotically AdS black holes. In particular, we formulate the variational problem for N = 2 STU supergravity in four dimensions with boundary conditions corresponding to those obeyed by the so called 'subtracted geometries'. We show that such boundary conditions can be imposed covariantly in terms of a set of asymptotic second class constraints, and we derive the appropriate boundary terms that render the variational problem well posed in two different duality frames of the STU model. This allows us to define finite conserved charges associated with any asymptotic Killing vector and to demonstrate that these charges satisfy the Smarr formula and the first law of thermodynamics. Moreover, by uplifting the theory to five dimensions and then reducing on a 2-sphere, we provide a precise map between the thermodynamic observables of the subtracted geometries and those of the BTZ black hole. Surface terms play a crucial role in this identification. Keywords: M-Theory, Black Holes, String Theory, Gauge-gravity correspondence Published in DKUM: 27.06.2017; Views: 2851; Downloads: 388 Full text (834,82 KB) This document has many files! More... |
8. General U(1) x U(1) F-theory compactifications and beyond: geometry of unHiggsings and novel matter structureMirjam Cvetič, Denis Klevers, Hernan Piragua, Washington Taylor, 2015, original scientific article Abstract: We construct the general form of an F-theory compactification with two U(1) factors based on a general elliptically fibered Calabi-Yau manifold with Mordell-Weil group of rank two. This construction produces broad classes of models with diverse matter spectra, including many that are not realized in earlier F-theory constructions with U(1) x U(1) gauge symmetry. Generic U(1) x U(1) models can be related to a Higgsed non-Abelian model with gauge group SU(2) x SU(2) x SU(3), SU(2)(3) x SU(3), or a subgroup thereof. The nonlocal horizontal divisors of the Mordell-Weil group are replaced with local vertical divisors associated with the Cartan generators of non-Abelian gauge groups from Kodaira singularities. We give a global resolution of codimension two singularities of the Abelian model; we identify the full anomaly free matter content, and match it to the unHiggsed non-Abelian model. The non-Abelian Weierstrass model exhibits a new algebraic description of the singularities in the fibration that results in the first explicit construction of matter in the symmetric representation of SU(3). This matter is realized on double point singularities of the discriminant locus. The construction suggests a generalization to U(1)(k) factors with k > 2, which can be studied by Higgsing theories with larger non-Abelian gauge groups. Keywords: F-theory, differential geometry, algebraic geometry, gauge symmetry Published in DKUM: 14.06.2017; Views: 1274; Downloads: 397 Full text (1,36 MB) This document has many files! More... |
9. Vertical displacements measuring methods during bridge load testsBoštjan Kovačič, Ante Marendić, Rok Kamnik, Mikhail Volkov, Vera Roy, 2016, published scientific conference contribution Abstract: This article introduces the use of the GNSS method for the load testings of bridge structures. We know that there area lot of methods by which you can determine vertical displacement. However, as new bridge constructions are constructed over almost impossible and inaccessible gorges and valleys, the classic measurements method do not allow us to determine vertical displacement so reliably any more or they are very time-consuming. The GNSS method is well known but there are difficulties when determining the altitude component of this method, which is rather questionable. For this purpose, the methods were tested as practical examples in which some difficulties were encountered, so subsequently another test recording was performed of altitude changes using this method. Keywords: bridges, measurements, strain gauge, load test, deformation, strain, signal processing Published in DKUM: 29.08.2016; Views: 2014; Downloads: 439 Full text (1,55 MB) This document has many files! More... |
10. Thread gauge calibration for industrial applicationsTadeja Primožič Merkač, Bojan Ačko, 2010, original scientific article Abstract: There are two most commonly used methods for calibration of thread rings, with different measuring uncertainty. The method of mechanical sensing with two balls is mostly used on one-axial measuring machines and on coordinate measuring machines. However, the method of calculating the core diameter of the thread ring combined with the technique of adaptation (in accordance with the method of the smallest squares) is used on the profile scanner. The required tolerances, which are very narrow for adjustable and laboratory thread ring, so the measuring uncertainty may be too high when using the method of mechanical sensing with two balls, and the low quality of some control rings, are the decisive factors for choosing an appropriate method in the industry. This also depends on the laboratoryćs capability of executing a specific method. The measurements of the core diameter of thread rings, which are the main topic of this article, were included into an international inter-comparison in which the main subject was the same thread ring as the one mentioned in this article. Keywords: thread ring gauge, calibration, pitch diameter, measurement uncertainty, dimensional measurements Published in DKUM: 31.05.2012; Views: 2381; Downloads: 41 Link to full text |