Events - Page 16

Time and place: Jan. 27, 2016 1:05 PM, Ø467

Andrzej Hryczuk, FI

The thermal relic abundance of the dark matter is now determined observationally to a per cent level accuracy. It is also an increasingly useful tool to exclude, constrain or motivate models beyond the Standard Model of particle physics. It comes then with no surprise that in the recent years a considerable effort has been made to revise and improve some of the aspects of thermal relic density calculations. In this talk I will concentrate on the important physics concepts used in such calculations, highlighting some less commonly discussed details. Towards the end I will show some recent results, serving as examples of the relevance of the effects studied.

(The slides are now available)

Time and place: Jan. 22, 2016 3:15 PM4:00 PM, Seminar room (FV414)

Viktoriya Yarushina (IFE) will give a talk on "Fluid flow in shales from experimental and theoretical perspective"

Time and place: Jan. 20, 2016 1:05 PM, Ø467

Chad Finley, Oskar Klein Centre (Stockholm)

The IceCube Neutrino Observatory lies two kilometers deep within the ice at the South Pole, Antarctica.  With one cubic kilometer of instrumented volume, IceCube enables the study of a wide range of phenomena: neutrino astronomy, dark matter searches, neutrino oscillations, and cosmic ray physics.  Recently IceCube has announced the long-awaited discovery of high energy neutrinos from deep space.  These neutrino energies are approximately 100 million times greater than the energies of neutrinos previously observed from the sun and supernovae. I will review IceCube's latest results with particular attention to this new flux. I will also discuss what we hope to measure in the near future with IceCube and the next generation of neutrino telescopes.

(The Slides are now available)

Time and place: Jan. 8, 2016 3:15 PM4:00 PM, Seminar room (FV414)

Yuri Galperin (Professor emeritus, Condensed matter physics, AMKS, UiO) will give a seminar in order to help us on (tentative plan) 1. How to write a referee report on a submission? 2. How to respond to referee's remarks (sometimes stupid)? 3. How to evaluate a grant application?

Time and place: Dec. 11, 2015 2:15 PM3:00 PM, FV414

Thi Thuy Luu (UiO, PGP) will talk about HBV (Buskerud and Vestfold University CollegeTønsberg, Norway) lab facilities. She will also talk about her PhD work that she did there about "Solid liquid interdiffusion (SLID) wafer-level bonding for MEMS packaging".

 

.

Time and place: Dec. 4, 2015 4:15 PM5:00 PM, Seminar room (FV414)

This wine seminar reports on a field expedition/worskhop in the northern Patagonian Andes that involved 8 PGP people. The menu of the presentation is: volcanoes, amazing geology, stunning landscape, condors, gauchos and… Asado!!!   The presenters are, so far and not in order: - Olivier - Maya (to confirm) - Alban - Frank - Håvard.

Time and place: Dec. 2, 2015 1:05 PM, Ø467

Stefan Hofmann, LMU Munich

A relativistic framework for describing black-hole interiors as bound states of a large number of quantum constituents will be presented. The macroscopic and microscopic description can be linked via a simple scaling law relating the black-hole mass to the number of black-hole constituents.

(The slides will be available after the talk).

Time and place: Dec. 1, 2015 10:15 AM4:00 PM, Auditorium 2, Helga Engs hus

Trial lecture: Directional Solidification of Metallic Alloys: From Dendrites and Seaweeds, to Casts and Turbine Plates (10:15)

Dissertation: Non-equilibrium pattern formation in reactive channel flow (13:15)

Time and place: Nov. 27, 2015 3:15 PM4:00 PM, Seminar room (FV414)

Felix Ritort (Facultat de Física, Universitat de Barcelona, Spain and Ciber-BBN of Biomaterials and Nanomedicine, ISCIII, Madrid, Spain) will talk about his research on statisical physics tools applied to single molecule experiments in biophysics.

Time and place: Nov. 25, 2015 1:05 PM, Ø467

Piero Ullio, SISSA (Trieste)

The dark matter puzzle is one of deepest and longest-standing problems in Science. While there is overwhelming evidence that dark matter is the building block of all structures in the Universe, its nature remains unknown.

There are several theoretical frameworks predicting that dark matter halos - including the halo of our own galaxy - are made of particles which can annihilate in pairs or decay into ordinary Standard Model states, giving rise to exotic astrophysical signals.

The focus in recent years has been in particular on the search for exotic components with gamma- and cosmic-ray observatories, with a dramatic improvement in quality and coverage of the available data. 

Unfortunately, for none of the originally proposed targets a dark matter signal stands clearly above backgrounds from standard astrophysical sources: it is then apparent that to keep exploiting these channels as efficient tools to either discover dark matter or set constraints on dark matter candidates, a closer addressing of signals and backgrounds are needed. 

We illustrate this point for two targets, the Galactic center and dwarfs satellites which most recently have been highlighted, respectively, as most promising for a tentative detection and most constraining on particle dark matter models.

Time and place: Nov. 18, 2015 1:05 PM, Ø467

Björn Herrmann, LAPTh (Annecy)

A powerful tool to constrain a new physics model is to predict the relic density of dark matter and compare it to the recent limits published by Planck in order to identify (dis)favoured regions of parameter space. After reviewing the standard calculation of the dark matter relic density in the freeze-out picture, I will discuss several uncertainties entering this calculation. Focusing then on the particle physics aspects, I will consider the case of the Minimal Supersymmetric Standard Model and present the project DM@NLO, which aims at improving the preciction of the neutralino relic density by including radiative corrections to the (co)annihilation cross-section of the dark matter candidate. In particular, I will show that the impact of these corrections can be numerically larger than the current experimental uncertainty on cosmological data.

(The slides are now available).

Time and place: Nov. 13, 2015 3:15 PM4:00 PM, Seminar room (FV414)

Bjarte Aarseth (The viking ship museum, Museum of Cultural History, UiO) will present us his work on 3D scanning and digital visualisation of Vikingship and Norwegian icons.

Time and place: Nov. 11, 2015 1:05 PM, Ø467

Joachim Kopp, University of Mainz

We consider two scenarios in which the first experimental hint for the particle physics nature of dark matter (DM) comes from highly boosted DM particles. The first scenario interprets the high energy events observed in IceCube as a signal of PeV DM decaying to a much lighter state, which in turn is detected in IceCube. The model explains the event rate and spectrum observed in IceCube, it shows a preference for shower-like events at the highest energies, and it features a small dip in the spectrum at few hundred TeV.  The second scenario is a very generic dark photon model. We point out that DM production at the LHC can be accompanied by final state radiation in the form of "dark photons", which decay back to SM particles.  We discuss this process analytically and numerically in analogy to collinear particle showers in QED and QCD. The smoking gun signal of this "radiating DM" scenario are collimated jets or lepton jets with unusual properties.

(The slides are now available.)

Time and place: Nov. 6, 2015 2:35 PM6:00 PM, Seminar room (FV414)

Are you also curious to know what research is brewing on the other side of the hall in PGP-AMKS group? Please join us to listen to short talks by our new colleagues, and to look at some posters!

Time and place: Nov. 5, 2015 12:15 PM1:00 PM, Seminar room (FV414)

Fei Liu (Physics of Complex Fluids, Dept. Science and Technology University of Twente, The Netherlands) has applied for a PostDoc funded by an ERC (Bjørn Jamtveit) to work at PGP on measuring surface forces between minerals and fluids using AFM and SFA.  

Time and place: Nov. 4, 2015 1:05 PM, Ø467

Bryan Webber, University of Cambridge

Tests of the Standard Model and searches for new phenomena at the Large Hadron Collider depend heavily on computer simulations of signal and background processes.  Monte Carlo event generators aim to simulate the final states of high-energy collisions in full detail, down to the level of individual stable particles.   The talk will review the physics behind these programs, their main ingredients and theoretical status, with emphasis on recent work to improve their precision.  Comparisons with the latest LHC data will illustrate these developments, and the places where further improvements are needed.

(The Slides are now available)

Time and place: Oct. 28, 2015 12:15 PM1:00 PM, PGP seminar room (V414, Physics building)

Sam Poppe, PhD student at the Vrije Universiteit Brussel, will present his work on "X-raying an unusual patient : imaging analogue experiments of volcanic intrusions using X-ray Computed Tomography".

Time and place: Oct. 23, 2015 3:15 PM4:00 PM, Seminar room (FV414)

Andreas Carlson (Dept of Mathematics, UiO) will present us his work.

Time and place: Oct. 21, 2015 1:05 PM, Ø467

Gabrijela Zaharijas, University of Nova Gorica

The Isotropic Gamma-ray Background (IGRB) up to 820 GeV has been recently measured by the Fermi LAT using 50 months of data. Understanding the origin of this IGRB is a crucial task that requires to identify and model possible contributions in detail. Dark matter annihilation signals integrated over all cosmic epochs have been proposed to account for a portion of the measured IGRB intensity. I will discuss the theoretical predictions for the clustering of dark matter signal and refined predictions for the contribution of the unresolved astrophysical source populations to the IGRB. We use these ingredients to set the limits on the dark matter annihilation cross section which turn out to be comparable to the ones set by the observation of dwarf spheroidal galaxies and Milky Way halo for sub-TeV dark matter masses, while they improve upon them at the high mass end due to the significant energy extension of the isotropic measurement. In addition I will  compare these finding with complementary techniques which probe the cosmological dark matter annihilations, as those of the small scale angular anisotropies and gamma ray cross correlations with galaxy catalogs.

(Slides are now available)

Time and place: Oct. 16, 2015 2:15 PM3:15 PM, Seminar room (FV414)

Erik Fooladi (Høgskulen i Volda) will talk about food, gastronomy and sciences.

* Note that the seminar will exceptionnaly be at 14:15! *

 

Time and place: Oct. 14, 2015 1:05 PM, Ø467

David Mota, ITA

Several extensions of the standard cosmological model include scalar fields as new degrees of freedom in the underlying gravitational theory. A particular class of these scalar field theories include screening mechanisms intended to hide the scalar field below observational limits in the solar system, but not on galactic scales, where data still gives freedom to find possible signatures of their presence.  I describe how one can use structure formation to study screening mechanisms in extensions to General Relativity. In particular, I will present observable signatures of modified gravity in the nonlinear matter power spectrum, on the halo mass function and other properties of galaxy clusters. Those would help us to discriminate between models with and without scalar fields and even between different screening mechanisms.

(The slides are now available)

Time and place: Oct. 2, 2015 9:00 AMOct. 3, 2015 1:00 PM, Helga Engh, aud. 2
Time and place: Sep. 24, 2015 5:30 PM, The Norwegian Academy of Science and Letters

Dr. Terry Onsager, National Oceanic and Atmospheric Administration, USA/Space Weather Prediction Center, USA.

Time and place: Sep. 18, 2015 3:15 PM4:00 PM, Seminar room (FV414)

 David Fonseca Mota from the Institute of Theoretical Astrophysics at UiO will present us his work. He comes for the second time in our group, and he will present us the second part of his talk (see the complete summary under).

Time and place: Sep. 16, 2015 1:05 PM, Ø467

Kåre Olaussen, NTNU Trondheim

After 100 years people are still trying to modify (or mutilate) the Einstein General Theory of Relativity. I will first give a general overview of various possibilities, as I learned at a workshop this summer.

Next I will discuss in more detail the possibility of a non-minimal coupling of Einstein gravity to scalar fields, and some modest computations I have done with a master student on that model (in the Robertson-Walker geometry).

The presentation will mainly be aimed at an audience with limited experience with general relativity.

(Slides will be available after the talk).