A group of Early-Career Researchers (ECRs) has been given a mandate from the European Committee for Future Accelerators (ECFA) to debate the topics of the current European Strategy Update (ESU) for ...Particle Physics and to summarise the outcome in a brief document 1. A full-day debate with 180 delegates was held at CERN, followed by a survey collecting quantitative input. During the debate, the ECRs discussed future colliders in terms of the physics prospects, their implications for accelerator and detector technology as well as computing and software. The discussion was organised into several topic areas. From these areas two common themes were particularly highlighted by the ECRs: sociological and human aspects; and issues of the environmental impact and sustainability of our research.
The Compact Linear Collider (CLIC) is a proposed future high-luminosity linear electron-positron collider operating at three energy stages, with nominal centre-of-mass energies: 380 GeV, 1.5 TeV, and ...3 TeV. Its aim is to explore the energy frontier, providing sensitivity to physics beyond the Standard Model (BSM) and precision measurements of Standard Model processes with an emphasis on Higgs boson and top-quark physics. The opportunities for top-quark physics at CLIC are discussed in this paper. The initial stage of operation focuses on top-quark pair production measurements, as well as the search for rare flavour-changing neutral current (FCNC) top-quark decays. It also includes a top-quark pair production threshold scan around 350 GeV which provides a precise measurement of the top-quark mass in a well-defined theoretical framework. At the higher-energy stages, studies are made of top-quark pairs produced in association with other particles. A study of ttH production including the extraction of the top Yukawa coupling is presented as well as a study of vector boson fusion (VBF) production, which gives direct access to high-energy electroweak interactions. Operation above 1 TeV leads to more highly collimated jet environments where dedicated methods are used to analyse the jet constituents. These techniques enable studies of the top-quark pair production, and hence the sensitivity to BSM physics, to be extended to higher energies. This paper also includes phenomenological interpretations that may be performed using the results from the extensive top-quark physics programme at CLIC.
Detector Technologies for CLIC Abusleme Hoffman, A C; Parès, G; Fritzsch, T ...
arXiv.org,
05/2019
Paper, Journal Article
Odprti dostop
The Compact Linear Collider (CLIC) is a high-energy high-luminosity linear electron-positron collider under development. It is foreseen to be built and operated in three stages, at centre-of-mass ...energies of 380 GeV, 1.5 TeV and 3 TeV, respectively. It offers a rich physics program including direct searches as well as the probing of new physics through a broad set of precision measurements of Standard Model processes, particularly in the Higgs-boson and top-quark sectors. The precision required for such measurements and the specific conditions imposed by the beam dimensions and time structure put strict requirements on the detector design and technology. This includes low-mass vertexing and tracking systems with small cells, highly granular imaging calorimeters, as well as a precise hit-time resolution and power-pulsed operation for all subsystems. A conceptual design for the CLIC detector system was published in 2012. Since then, ambitious R&D programmes for silicon vertex and tracking detectors, as well as for calorimeters have been pursued within the CLICdp, CALICE and FCAL collaborations, addressing the challenging detector requirements with innovative technologies. This report introduces the experimental environment and detector requirements at CLIC and reviews the current status and future plans for detector technology R&D.
Test beam measurements at the test beam facilities of DESY have been conducted to characterise the performance of the EUDET-type beam telescopes originally developed within the EUDET project. The ...beam telescopes are equipped with six sensor planes using MIMOSA26 monolithic active pixel devices. A programmable Trigger Logic Unit provides trigger logic and time stamp information on particle passage. Both data acquisition framework and offline reconstruction software packages are available. User devices are easily integrable into the data acquisition framework via predefined interfaces. The biased residual distribution is studied as a function of the beam energy, plane spacing and sensor threshold. Its standard deviation at the two centre pixel planes using all six planes for tracking in a 6\,GeV electron/positron-beam is measured to be \((2.88\,\pm\,0.08)\,\upmu\meter\).Iterative track fits using the formalism of General Broken Lines are performed to estimate the intrinsic resolution of the individual pixel planes. The mean intrinsic resolution over the six sensors used is found to be \((3.24\,\pm\,0.09)\,\upmu\meter\).With a 5\,GeV electron/positron beam, the track resolution halfway between the two inner pixel planes using an equidistant plane spacing of 20\,mm is estimated to \((1.83\,\pm\,0.03)\,\upmu\meter\) assuming the measured intrinsic resolution. Towards lower beam energies the track resolution deteriorates due to increasing multiple scattering. Threshold studies show an optimal working point of the MIMOSA26 sensors at a sensor threshold of between five and six times their RMS noise. Measurements at different plane spacings are used to calibrate the amount of multiple scattering in the material traversed and allow for corrections to the predicted angular scattering for electron beams.
The
Academic Freedom Index
is the first conceptually thorough assessment of academic freedom worldwide and a times series dataset going back to 1900. While some previous datasets exist, they are ...geographically limited and methodologically or conceptually insufficient to offer a comprehensive picture of the levels of academic freedom across time and space. This paper introduces the new expert-coded dataset that includes the overall
Academic Freedom Index
alongside several specific indicators, to which more than 2050 country experts around the world have contributed and which is freely available as part of V-Dem’s time-series data releases. The paper discusses its advantages compared to other types of data on academic freedom, details the conceptualization of the new indicators, and offers a content and convergent validation of the results. The dataset provides ample opportunities for scholars to conduct in-depth research on academic freedom and its infringements, and for policymakers and advocates to monitor and analyze patterns and trends of academic freedom around the world.
This book provides empirically grounded insights into the causes, trajectories, and effects of a severe decline in university autonomy and the relationship to other dimensions of academic freedom by ...comparing in-depth country studies and evidence from a new global timeseries dataset. Drawing attention to ongoing discussions on standards for monitoring and assessment of academic freedom at regional and international organizations, this book identifies a need for clearer standards on academic freedom and a human rights-based definition of university autonomy. Further, the book calls for accompanying international oversight and the inclusion of criteria related to academic freedom in international university rankings. Five expert-authored case studies on academic freedom from diverse nations (Bangladesh, Mozambique, India, Poland, and Turkey) are included in the volume. Drawing on both qualitative and quantitative evidence, the book offers a unique and timely contribution to the field and will be of great interest to scholars, researchers, and students in the fields of higher education, human rights, political science and public policy.
Material deprivation in the EU Israel, Sabine; Spannagel, Dorothee
Acta sociologica,
05/2019, Letnik:
62, Številka:
2
Journal Article
Recenzirano
The central aim of this paper is identifying the existing political leeway for the reduction of deprivation levels in Europe. The links between household and individual characteristics and risks of ...material deprivation have been abundantly researched, but what are the political institutions that modify and possibly buffer these odds? Welfare state differences have been portrayed in depth but their association with social outcomes such as deprivation is less clear. By identifying the impact of decommodification and defamilisation policies on deprivation exposure, we seek to fill this gap. Our results, based on European Union Statistics on Income and Living Conditions 2012 to 2013 cross-sectional micro data, reveal that social programmes that cover large segments of the population and follow a needs-based approach are linked to lower odds of being materially deprived. A significant number of European cross-country differences in deprivation rates can thus be traced back to varying levels of social assistance, as well as to differences in the provision of public healthcare. Defamilisation policies are, despite increased risks for (single parent) families, not yet addressing the problem of low living standards successfully. An extension of childcare services, however, seems promising for lowering deprivation among families, particularly in countries with high levels of involuntary part-time work.
Abstract
Ice multiplication processes are known to be responsible for the higher concentration of ice particles versus ice nucleating particles in clouds, but the exact secondary ice formation ...mechanisms remain to be quantified. Recent in-cloud observations and modeling studies have suggested the importance of secondary ice production upon shattering of freezing drizzle droplets. In one of our previous studies, four categories of secondary ice formation during freezing of supercooled droplets have been identified: breakup, cracking, jetting, and bubble bursts. In this work, we extend the study to include pure water and an aqueous solution of analog sea salt drizzle droplets moving at terminal velocity with respect to the surrounding cold humid air. We observe an enhancement in the droplet shattering probability as compared to the stagnant air conditions used in the previous study. Under free-fall conditions, bubble bursts are the most common secondary ice production mode in sea salt drizzle droplets, while droplet fragmentation controls the secondary ice production in pure water droplets.
