Friday, 30 May 2014

Planck 2014 Liveblog: Day Five Session 3

We return after lunch for another session of leptonic physics.

2:30 pm: Leptonic CP violation and see-saw, Alexei Smirnov

Lepton CP phases are unmeasured parameters that we know exist.  Chance to make predictions!

How to measure CP phase?  Accelerators/long baseline experiments, new and planned experiments, results by 2020s.  Atmospheric neutrino measurements, perhaps 10 years.

PINGU, not a naughty penguin but an upgrade for IceCube.  Energy threshold down to few GeV.  Long-term goal at IceCube is MICA, with 0.01 GeV threshold and megaton acceptance.

Look for CP phases in eμ and μμ neutrino oscillations.  Shift in probabilities as function of energy.  Highly sensitive in GeV-energy scale.  Systematics will be a serious problem.  Even at SuperPINGU, 10% systematics can reduce significance of measuring δ from 5 to 3.

Predictions: from quark-lepton similarity.  Motivated by e.g. GUTs.  Leads to small δ, but problem is why?  LH and RH rotations both relevant for neutrinos.

CPV can also be related to see-saw, and possibly enhanced by it.

3:00 pm: Leptogenesis, inflation and the maximal temperature of the universe, Wilfried Buchmuller

Leptogenesis + SUSY makes MSSM neutralino inconsistent.  What of gravitino?  Can work, but reheating temperature for gravitino production then very close to minimal temperature needed for thermal LG.  Why is this?  Could it be because reheating comes from decay of heavy neutrino?

Model: SUSY B-L SU(5)-like structure.  Decays of B-L gauge bosons, Higgs leads to plateau in temperature of Universe dominated by neutrino properties.  Leads to a matter to radiation dominated period.  Importance of neutrino parameters makes model predictive, and testable at LHC.

Testing of this early phase of the universe: gravitational waves.  (Pretty much everything else is impossible.)  Spectrum can be used to predict LG temperature.  Same as inflation, but different normalisation.

3:30 pm: F-term axion monodromy inflation, Fernando Marchesano Buznego

String-theory motivated inflation.  How to have a natural inflation consistent with BICEP.

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