Inflationary cosmology’s account for the emergence of the seeds of structure in the universe out of primordial quantum fluctuations is empirically successful as far as the so called scalar modes is concerned, but the situation is no so clear regarding the tensor modes. On the other hand, the usual account has some serious conceptual problems, connected to the quantum macro-objectification question ( usually known as the measurement problem in quantum theory). In the search for an approach to resolve the latter, we find substantially modified predictions (with respect to the standard ones) for one of the observables, specifically the estimates for the amplitude and shape of the spectrum of primordial gravity waves. This is an interesting example, where considerations that might have been initially thought to be “just of philosophical interest” actually led to novel and (so far better) predictions for empirical facts.
Keywords: quantum theory, cosmology, inflation, evolution of the universe
The origin of the astrophysical neutrino signal detected by IceCube is still mysterious. Several extragalactic sources have been proposed as possible accelerators of the high energy protons (or nuclei) whose interaction with gas or radiation is expected to trigger the neutrino emission. The detection of the well reconstructed event IC-170922A on September 2017, potentially associated with the BL Lac TXS 0506+056 is drastically changing the scenario. I will discuss the interpretation of this event in the framework of the blazar models and the consequences for our knowledge of the jet physics.
Fabrizio Tavecchio is a well-known phenomenologist in astrophysics working in the National Astronomical Observatory of Brera in Italy especially in the interpretation of high-energy observations (very high-energy gamma-ray, high-energy neutrinos) specialized in AGN sources.
In preparation for a Lepton Collider in the multi-TeV range which will possibly be required for precision physics beyond the standard model if and when identified, novel acceleration techniques are being developed with attractive performance. After a review of the technology options being considered for an affordable e+/- linear collider at the energy frontier, the presentation will focus on Muon-based facilities which offer a unique potential to enable capabilities at both the Intensity Frontier with Neutrino Factories and the Energy Frontier with Muon Colliders ranging from Higgs to multi-TeV energies. By comparison with other technologies, through objectives Figures of Merit, a Muon Collider, is demonstrated to be the most promising option in the multi-TeV energy range. Muon based facilities rely on novel technologies with challenging parameters and critical issues from which the status and future plans of the R&D to demonstrate their feasibility is presented.
Keywords/Mots clés: Future Collider/Collisionneur Futur, Muon Collider/Collisionneur de muons, Accelerator/Accélérateur R&D, Neutrino Beam/Faisceau de Neutrinos, CERN
5 last Seminars
The recent discovery of high-energy astrophysical neutrinos has opened a new window to the Universe. Identifying the sources of those neutrinos is the most pressing question in the new field of neutrino astronomy. Combining neutrino data with electromagnetic measurements in a multi-messenger approach increases the sensitivity to identify the neutrino sources and helps to solve long-standing problems in astrophysics such as the origin of cosmic rays.
A first compelling candidate was identified on September 22, 2017, when the IceCube Neutrino Observatory observed an extremely high-energy neutrino, IceCube-170922, in spatial and temporal coincidence with a gamma-ray flaring blazar, TXS 0506+056, monitored by the Fermi Large Area Telescope. The coincidence triggered a large follow-up campaign in a broad wavelength band.
In this talk I will review the recent progress in multi-messenger astronomy using neutrino data with a focus on the candidate source, TXS 0506+056.
Anna Franckowiak is researcher in DESY in the IceCube collaboration specialized on the multi-messenger astronomy. She is involved since a long time in the electromagnetic follow-up of the high-energy neutrinos. She had also a leading role in the neutrino association with TXS 0506+056.
Gaia is an ESA astrometric mission launched end of 2013 for a nominal mission of five years. It is providing unprecedented astrometry (parallaxes and proper motions) and spectrophotometry for more than 1 billion sources brighter than G=20.7 mag.
It also provides spectrocopy for the brightest onces. By providing 3D spatial and velocity distributions of the stars combined with their astrophysical properties, Gaia is revolutionizing our knowledge of the Milky Way formation history and of stellar evolution. But it is also observing solar system objects, local group resolved stars, unresolved galaxies, quasars, it is alerting on photometric transients and will allow to perform relativistic tests.
I will present the content of the second Gaia data release together with a few of the many examples of its scientific exploitation, from survey calibration to dark matter constraints.
Keywords/Mots clés: CPPM, ATLAS Upgrade/Amélioration d'ATLAS, C3F8, Tracker cooling/Refroidissement du trajectographe
The IceCube Neutrino Observatory is a cubic-kilometer Cherenkov neutrino detector deployed in the glacial ice at the geographic South Pole. DeepCore, its denser sub-array, lowers the energy threshold for neutrino detection to less than 10 GeV. In recent years, IceCube became one of the leading instruments measuring the neutrino mixing parameters in the atmospheric sector. In addition, its data are used to search for new physics beyond the standard three-neutrino mixing. This talk discusses the most recent neutrino oscillation results from IceCube and future of in-ice measurements of fundamental neutrino properties.
The Belle II experiment at the SuperKEKB accelerator, a super flavour factory project in KEK in Japan, has started its operation in April this year. In the seminar we will review the motivation for precision studies in flavour physics as a promising new window for New Physics, describe the accelerator and the detector, and discuss the present status, immediate plans and prospects of the project.
Keywords/Mots clés: B-Physics/Physique du B, KEK, CP Violation in B mesons/Violation de CP dans les mésons beaux, Low energy & high luminosity e+e- collider/Collisionneur e+e- de basse énergie & de haute luminosité