HIP NEWS April 11th 2016
DEPARTMENT OF PHYSICS / HIP JOINT COLLOQUIA / SEMINARS
Tuesday 12 April 2016 at 10.15 in A315
Louis Lyons (Imperial College)
Statistical Issues in Searches for New Physics
Abstract: Given the cost, both financial and even more importantly in terms of human effort, in building High Energy Physics accelerators and detectors and running them, it is important to use good statistical techniques in analysing data. This talk covers some of the statistical issues that arise in searches for New Physics. They include topics such as: Blind Analysis. How should we deal with the `Look Elsewhere Effect’? Should we insist on the 5 sigma criterion for discovery claims? Significance P(A|B) is not the same as P(B|A). The meaning of p-values. What is Wilks’ Theorem and when does it not apply? Dealing with systematics such as background parametrisation. Coverage: What is it and does my method have the correct coverage? Upper Limits. The use of p_0 vs p_1 plots. Higgs search: Discovery and Spin.
Thursday 14 April 2016 at 10.15 in A315: Guy Moore (Darmstadt)
Relating the Axion Mass and Dark Matter Density
Abstract: QCD appears to allow for large parity and time-reversal violating effects, which are in fact unmeasurably small. The simplest dynamical model to explain this predicts a new particle, the Axion, which is also an excellent dark matter candidate. Under reasonable assumptions it should be possible to predict the relation between the axion’s mass and its dark matter abundance. I will discuss the interesting physics we need to make this prediction concrete — axionic string networks and topological susceptibility.
Wednesday 13 April 2016 at 14.15 in A315
Matti Herranen (Jyväskylä)
Nonequilibrium QFT approach to leptogenesis
Abstract: he observed baryon asymmetry of the Universe may have been produced dynamically in the very early Universe by a baryogenesis via leptogenesis process from the CP- and lepton number violating decays of heavy right-handed neutrinos. For reliable calculations of the baryon asymmetry generated in leptogenesis first principle methods of nonequilibrium quantum field theory are required.
We construct a transport theory of leptogenesis based on the Schwinger-Keldysh or Closed Time Path (CTP) formalism of nonequilibrium QFT. The resulting kinetic equations incorporate finite density medium effects and quantum coherence effects and therefore provide a generalization to standard (quantum) Boltzmann equations. We find that the finite density corrections from loop integrals typically lead to an enhancement of the asymmetry. In the resonant regime with nearly degenerate right-handed neutrino masses, our results confirm the well-known resonant enhancement of CP-violation, however, novel effects from the flavour oscillations can be important in the dynamics.
Wednesday 13 April 2016, Upcoming events for international staff
Sign up in http://www.helsinki.fi/trainingcalendar ( Staff Training Calendar HENKKA) or via https://elomake.helsinki.fi/lomakkeet/48601/lomake.html
Last sign-up date: 17.04.2016: Completing Your Tax Return Form – Veroilmoitus in English
Sign up in http://www.helsinki.fi/trainingcalendar ( Staff Training Calendar HENKKA)
L. Boldizsar 13.4. – 26.4. (EB)
M. Herranen 12.4. – 13.4. (FM)
A. Meroni 18.4. – 20.4. (AV)
G. Moore 13.4. – 15.4. (AV)
D. Varga 13.4. – 15.4. (EB)
M. Vargyas 11.4. – 15.4. (EB)