Foucault\u27s Pendulum, a Classical Analog for the Electron Spin State

Spin has long been regarded as a fundamentally quantum phenomena that is incapable of being described classically. To bridge the gap and show that aspects of spin\u27s quantum nature can be described classically, this work uses a classical Lagrangian based on the coupled oscillations of Foucault\u27s pendulum as an analog for the electron spin state in an external magnetic field. With this analog it is possible to demonstrate that Foucault\u27s pendulum not only serves as a basis for explaining geometric phase, but is also a basis for reproducing a broad range of behavior from Zeeman-like frequency splitting to precession of the spin state. By demonstrating that unmeasured electron spin states can be fully described in classical terms, this research opens the door to using the tools of classical physics to examine an inherently quantum phenomenon

Chances of Airborne SAR in the Investigation of Buried Archaeological Sites in Moist Soil in Bavaria

In the last few years, the use of Synthetic-Aperture-Radar (SAR) has become quite widespread owing to a dramatic improvement of the resolution of the corresponding sensors. After the first tests at sites in Syria (Linck, 2013; Linck et al., 2013), several further works have been published in recent years (e.g. Chen et al., 2016; Stewart et al., 2016; Lasaponara & Masini, 2019; Tapete & Cigna, 2019). All of these previous studies have two things in common: they are mainly investigating sites in desert and/or arid region and they are using satellite SAR data. With the use of Airborne SAR data, the resolution can be further improved due to the lower flight altitude, especially by applying a circular flight. Within this project, the chances of detecting buried archaeological remains in humid regions of Bavaria shall be investigated. All results are in-situ checked by previous GPR surveys of the Bavarian State Department of Monuments and Sites (BLfD)

Asymmetric introgression reveals the genetic architecture of a plumage trait

Genome-wide variation in introgression rates across hybrid zones offers a powerful opportunity for studying population differentiation. One poorly understood pattern of introgression is the geographic displacement of a trait implicated in lineage divergence from genome-wide population boundaries. While difficult to interpret, this pattern can facilitate the dissection of trait genetic architecture because traits become uncoupled from their ancestral genomic background. We studied an example of trait displacement generated by the introgression of head plumage coloration from personata to alba subspecies of the white wagtail. A previous study of their hybrid zone in Siberia revealed that the geographic transition in this sexual signal that mediates assortative mating was offset from other traits and genetic markers. Here we show that head plumage is associated with two small genetic regions. Despite having a simple genetic architecture, head plumage inheritance is consistent with partial dominance and epistasis, which could contribute to its asymmetric introgression. Hybrid zones are windows into the evolutionary process. Semenov et al. find that the head plumage differences between white wagtail subspecies have a simple genetic basis involving two small genetic regions, in which partially dominant and epistatic interactions help to explain how this sexual signal has become decoupled from other plumage traits

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Electroweak Production of Two Opposite-Sign W Bosons using the ATLAS Detector

Two studies involving the production of two opposite-sign W-bosons are performed using proton-proton collisions at $\sqrt{s} = 13$ TeV recorded by the ATLAS experiment at the Large Hadron Collider (LHC). For the first study, the two W-bosons are produced in association with no jets as a result of interactions between quarks and gluons. Once produced, the W-boson pair decays leptonically ($W^{+}W^{-} \rightarrow e^{+} \mu^{-} \nu_{e} \bar{\nu}_{\mu}$ or $W^{+}W^{-} \rightarrow \mu^{+} e^{-} \nu_{\mu} \bar{\nu}_{e}$). Measurements of the fiducial and differential cross sections are performed for this set of processes using data collected in 2015--2016 at a total integrated luminosity of $\mathscr{L} = 36.1$ $fb^{-1}$. The differential cross section is measured as a function of six observables. The measured fiducial and differential cross sections for this set of processes are compared with several theoretical predictions and several past measurements involving this process. Building on the results of the first study, the second study focuses on the electroweak production of two W-bosons in association with at least two jets. Once produced, the W-boson pair decays leptonically ($W^{+}W^{-} \rightarrow e^{+}e^{-} \nu_{e}\bar{\nu}_{e}$, $W^{+}W^{-} \rightarrow \mu^{+} \mu^{-} \nu_{\mu}\bar{\nu}_{\mu}$, $W^{+}W^{-} \rightarrow e^{+} \mu^{-} \nu_{e}\bar{\nu}_{\mu}$ or $W^{+}W^{-} \rightarrow \mu^{+} e^{-} \nu_{\mu}\bar{\nu}_{e}$). This study uses discovery significance and a set of optimized and trained neural networks to determine the viability of performing a cross section measurement for this process using the full Run 2 (2015--2018) dataset collected by ATLA

Electroweak Precision Measurements with the ATLAS Detector

As part of its ongoing exploration into the nature of the particles produced in high energy proton-proton collisions, the ATLAS detector has been used to perform a number of new precision electroweak measurements. In this talk the recent measurements of the W-boson mass, the Drell-Yan triple-differential cross-section and the polarisation of tau leptons in Z/γ* → ττ decays will be discussed

Observation and Measurements of Vector-Boson Pair Production with ATLAS

Observation and measurements of vector-boson pair production with ATLAS Measurements of electroweak boson pair scattering and inclusive production at the LHC constitute a stringent test of the electroweak sector and provide model-independent means to search for new physics at the TeV scale. They allow to test the gauge structure of the Standard Model. In this talk, we present recent results on vector-boson scattering from the ATLAS experiment using proton-proton collisions at √s=13 TeV. This includes the observation of WZ and same-sign-WW production via vector-boson scattering along with a measurement of VV production in semileptonic final states. If available, a measurement of