Standard Model physics at the LHC

In this contribution to the volume "From My Vast Repertoire -- The Legacy of Guido Altarelli" I discuss selected topics of Standard Model (SM) physics at the LHC and their connection to the work of Guido Altarelli. An overarching connection is given by Guido's fundamental contributions to our understanding of the strong force, parton distribution functions and their evolution, and techniques to calculate theoretical predictions through perturbative Quantum Chromodynamics. The increasingly precise LHC measurements of diverse processes can be confronted with SM predictions relying on these foundations to test the SM and contribute to the knowledge of the proton structure. The LHC experiments have also started to perform precise measurements of SM parameters, such as the mass of the W boson, and have measured a variety of processes sensitive to interactions of multiple electroweak bosons. The discovery of the Higgs boson in 2012 and the measurements of its properties are crucial to establish the nature of the mechanism of electroweak symmetry breaking and the status of these studies is summarised.Comment: Contribution to the volume "From my Vast Repertoire - the Legacy of Guido Altarelli" : 24 pages, 13 figure

Improving the representation of Arctic clouds in atmospheric models across scales using observations

With a nearly twice as strongly pronounced temperature increase compared to that of the Northern Hemisphere, the Arctic is especially susceptible to global climate change. The effect of clouds on the Arctic warming is especially uncertain, which is caused by misrepresented cloud microphysical processes in atmospheric models. This thesis aims at employing a scale- and definition-aware comparison of models and observations and will propose changes how to better parameterize Arctic clouds in atmospheric models. In the first part of this thesis, ECHAM6, which is the atmospheric component of the MPI-ESM global climate model, is compared to spaceborne lidar observations of clouds from the CALIPSO satellite. This comparison shows that ECHAM6 overestimates Arctic low-level, liquid containing clouds over snow- and ice-covered surfaces, which consequently leads to an overestimated amount of radiative energy received by the surface. Using sensitivity studies, it is shown that the probable cause of the model biases in cloud amount and phase is related to misrepresented cloud microphysical parameterization (i.e., parameterization of the Wegener-Bergeron-Findeisen process and of the cloud cover scheme) in ECHAM6. By revising those processes, a better representation of cloud amount and cloud phase is achieved, which helps to more accurately simulated the amount of radiative energy received by the Arctic in ECHAM6. The second part of this thesis will focus on a comparison of kilometer-scale simulation with the ICON model to aircraft observations from the ACLOUD campaign that took place in May/June 2017 over the sea ice-covered Arctic Ocean north of Svalbard, Norway. By comparing measurements of solar and terrestrial surface irradiances during ACLOUD flights to the respective quantities in ICON, it is shown that the model systematically overestimates the transmissivity of the mostly liquid clouds during the campaign. This model bias is traced back to the way cloud condensation nuclei get activated into cloud droplets in the two-moment, bulk microphysical scheme used. By parameterizing subgrid-scale vertical motion as a function of turbulent kinetic energy, a more realistic CCN activation into cloud droplets is achieved. This consequently results in an improved representation of cloud optical properties in the ICON simulations. Furthermore, the results of two studies to which contributions have been made during the Ph.D. will be summarized. In Petersik et al. 2018, the impact of subgrid-scale variability in clear-sky relative humidity on hygroscopic growth of aerosols in the aerosol-climate model ECHAM6-HAM2 has been explored. It was shown that the revised parameterization of hygroscopic growth of aerosols resulted in a stronger swelling of aerosol particles, which consequently causes an increased backscattering of solar radiation. In the study of Costa-Suros et al. 2019, it is explored whether it is possible to detect and attribute aerosol-cloud interactions in large-eddy simulation over Germany. It was shown that an increase in cloud droplet number concentration could be attributed to an increased aerosol load, while such an attribution was not possible for other cloud micro- and macrophysical variables

Electroweak Measurements with the ATLAS and CMS Experiments

Highlights of ATLAS and CMS measurements involving the production of heavy electroweak gauge bosons, W and Z, at the LHC are presented. Cross sections of single W and Z bosons are studied with very high precision and differential in various kinematic variables. The rapidity differential measurements are shown to have a so far unique impact on our knowledge of proton structure with regards to the strange quark density. The production in association with one or more light or heavy flavour jets is studied. Furthermore measurements of {\tau} final states, W polarisation and the weak mixing angle sin2{\theta}W are presented. Various di-boson measurements are presented and measurements are in general found to be well described by the Standard Model predictions. These measurements test the non-Abelian gauge structure and limits on anomalous triple gauge couplings are derived, which are of impact comparable to the corresponding LEP and Tevatron results.Comment: 8 pages, 12 figures. To appear in the proceedings of the 47th Recontres de Moriond, EW session, 201

Publication of Atmospheric Model Data using the ATMODAT Standard

Scientific data should be published in a way so that other scientists can benefit from these data, enabling further research. The FAIR Data Principles are defining the basic prerequisite for a good data publication: data should be Findable, Accessible, Interoperable, and Reusable. Increasingly, research communities are developing discipline-specific data publication standards under consideration of the FAIR Data Principles. A very comprehensive yet strict data standard has been developed for the climate model output within the Climate Model Intercomparison Project (CMIP), which largely builds upon the Climate and Forecast Metadata Conventions (CF conventions). There are, however, many areas of atmospheric modelling where data cannot be standardised according to the CMIP data standard because, e.g., the data contain specific variables which are not covered by the CMIP standard. Furthermore, fulfilling the strict CMIP data standard for smaller Model Intercomparison Projects (MIPs) requires much effort (in time and manpower) and hence the outcome of these MIPs often remains non-standardised. For innovative model diagnostics, preexisting standards are also not flexible enough. For that reason, the ATMODAT standard, a quality guideline for atmospheric model data, was created. The ATMODAT standard defines a set of requirements that aim at ensuring the high reusability of atmospheric model data publications. The requirements include the use of the netCDF file format, the application of the CF conventions, rich and standardised file metadata, and the publication of the data with a DataCite DOI. Additionally, a tool for checking the conformity of data and metadata to this standard, the atmodat data checker, was developed and is available on GitHub under an open licence. By using the more flexible ATMODAT standard, the publication of standardised datasets is simplified for smaller MIPs. This standardisation process is presented as an example using the data of an aerosol-climate model from the AeroCOM MIP. Furthermore, the landing pages of ATMODAT-compliant data publications can be highlighted with the EASYDAB logo. EASYDAB (Earth System Data Branding) is a newly developed quality label for carefully curated and highly standardised data publications. The ATMODAT data standardisation can easily be transferred to data from other disciplines and contribute to their improved reusability

a simple robust scaleinvariant text feature detector

In this paper we present SITT, a simple robust scaleinvariant text feature detector for document mosaicing. Digital image stitching has been studied for several decades. SIFT-Features in combination with RANSAC algorithm are established to produce good panoramas. The main problem of realtime text document stitching is the size of the feature set created by SIFT-Features. We introduce SITT-Features to solve this problem. Our experiments denote that for document images SITT-Features produce faster good results than SIFT-Features

Timeliness of notification systems for infectious diseases: A systematic literature review.

Timely notification of infectious diseases is crucial for prompt response by public health services. Adequate notification systems facilitate timely notification. A systematic literature review was performed to assess outcomes of studies on notification timeliness and to determine which aspects of notification systems are associated with timely notification

Organic Food Claims in Europe

Better regulatory guidelines, improved testing methods, and additional research into product quality criteria are needed to further develop the European organic food market