Programm für das Wintersemester 2019/2020
Mittwochs, 13:00 Uhr s.t.
Kaffee und Tee ab 14:00 UhrOrt: Institut für Physik, Lorentz-Raum 05-127, Staudingerweg 7
|30.10.19||Verena Spatz, TU Darmstadt|
Physics Education It is a widely held view that in the field of physics education the implementation of scientific findings into instruction practice should be a critical issue, however the record of research results on genuine classroom activities is generally poor. In the seminar, a project will be presented, that aims at closing this research-practice gap. In the project, novel teaching units on the introduction to Newtonian mechanics were developed and evaluated, based on empirical studies concerning common pre-instruction ideas, which students bring along into school. Some of these ideas are appropriate, whereas many are inappropriate to build upon in physics lessons. A very popular erroneous idea about motion is that a force is needed to keep an object moving at constant velocity. This novices concept has to be changed into an experts concept, that a force is needed only to change the velocity of an object. As illustrated in this example, teaching and learning physics often requires conceptual change. Considering this, the content area itself had to be restructured and teaching materials had to be prepared to meet students learning needs. An accompanying quasi-experimental field study with grade seven classes showed a significant improvement of students conceptual understanding.
|06.11.19||Karin Schönning, Upsala University|
Many challenges in modern physics manifest themselves in the proton. Despite being known for a century, it is to this day difficult to describe properties like its mass, spin, structure, size and abundance from first principles. One strategy when you have a system you dont fully understand, is to make a small change to the system and see how it reacts. In the case of the proton, we can replace one of the light quarks with a heavier one and thereby obtain a hyperon. Hyperons have the advantage over protons and neutrons that their spin is traceable through their weak, parity violating and thereby self-analysing decay. In this talk, I will outline how various aspects of hyperons can shed light on two of the puzzles related to the proton: the structure and the abundance. In particular, I will discuss how two recent measurement by the BESIII collaboration exploit the unique properties of hyperons and pave the way for a new generation of hyperon physics experiments.
|13.11.19||Alejandro Kievsky, INFN Pisa|
The short-range interaction between particles many times shows a strong repulsion that strongly correlated the many-body system. In the particular case of a two-body shallow state, very extended compared to the range of the interaction, the three-body system has universal behavior. There is an infinite number of states geometrically accumulated at E=0. This is the Efimov effect predicted by V. Efimov in 1970 and experimentally verified more than 25 years later. I will discuss how universal behavior emerges in strongly correlated systems as liquid drops or light nuclear systems and how this behavior propagates as the number of particle increases.
|20.11.19||Christian Weinheimer, Universität Münster|
Since the discovery of neutrino oscillation we know that neutrinos have non-zero masses, but we do not know the absolute neutrino mass scale, which is as important for cosmology as for particle physics. The direct search for a non-zero neutrino mass from endpoint spectra of weak decays is complementary to the search for neutrinoless double beta-decay and analyses of cosmological data. Today the most stringent direct limits on the neutrino mass originate from investigations of the electron energy spectra of tritium beta-decay. The next generation experiment KATRIN, the Karlsruhe Tritium Neutrino experiment, is improving the sensitivity from the tritium beta decay experiments at Mainz and Troitsk of 2 eV/c^2 by one order of magnitude probing the region relevant for structure formation in the universe. KATRIN uses a strong windowless gaseous molecular tritium source combined with a huge MAC-E-Filter as electron spectrometer. To achieve the sensitivity, KATRIN has been putting many technologies at their limits. The full 70m long setup has been successfully commissioned. From early 2019 on KATRIN is taking high statistics tritium data hunting for the neutrino mass. In this talk an introduction into the necessity to determine the neutrino mass and the status in the field will be given, followed by a detailed presentation of KATRIN and its results from the first KATRIN science run. The new results are already bringing KATRIN into the lead position of the field. In the outlook the perspectives of KATRIN for the coming years and new technologies in the field to potentially improve further the sensitivity on the neutrino mass will be presented.
|27.11.19||Javier Menéndez, Universitad de Barcelona|
The rare decay of atomic nuclei known as neutrinoless double-beta Decay is a unique process. Here, a nucleus decays by turning two neutrons into two protons, emitting two electrons without the usual balance of antineutrinos. Therefore, two particles---two electrons---are effectively created. Neutrinoless double-beta decay is the most promising attempt to test lepton number conservation in the laboratory. The observation of neutrinoless double-beta decay would proof that neutrinos are its own antiparticle, can clarify the origin of the prevalence of matter over antimatter in the universe, and determine the absolute neutrino mass. In spite of formidable experimental efforts, neutrinoless double-beta decay remains elusive, with half-live limits set over 10^25 years in some nuclei. The decay rate depends critically on the nuclear structure of the initial and final nuclei. This is encoded in the nuclear matrix element, which is key to anticipate the reach of experiments and to fully extract all physics information from a future measurement. In this PRISMA+ colloquium I will summarize the status of double-beta decay searches, and highlight recent efforts to obtain reliable nuclear matrix elements from first principles.
|11.12.19||Torben Ferber, DESY Hamburg|
Belle II in Japan is a flagship experiment at the intensity frontier that started data taking this year after massive upgrades of the accelerator and the detector. In this talk I will report on the performance of the Belle II detector and first rediscoveries with the 2019 dataset. In the second part of the talk I will give an overview about the planned Belle II physics program for the next year with a focus on searches for Dark Sectors and Long-Lived Particles.
|18.12.19||Felix Kahlhoefer, RWTH Aachen|
Light dark matter
|08.01.20||Cristina Lazzeroni, University Birmingham, UK|
NA62 results on the K+ ➞ π+νν̄ decay
|15.01.20||Christian Fischer, Universität Gießen|
Baryon spectra from QCD
|22.01.20||Assumpta Parreno, Universitad de Barcelona|
Lattice QCD calculations of/on light (hyper) nuclear systems
|29.01.20||Jonathan Butterworth, UCL London|
New physics and model independent measurements at the LHC
|Prof. Dr. Stefan Tapprogge|
Institut für Physik, ETAP