Low-l CMB from string-scale SUSY breaking?

作者：Sagnotti A^*

来源：Modern Physics Letters A, 2017, 32(1): 1730001.

DOI：10.1142/S0217732317300014

Models of inflation are instructive playgrounds for supersymmetry (SUSY) breaking in Supergravity and String Theory. In particular, combinations of branes and orientifolds that are not mutually BPS can lead to brane SUSY breaking, a phenomenon where nonlinear realizations are accompanied, in tachyon-free vacua, by the emergence of steep exponential potentials. When combined with milder terms, these exponentials can lead to slow-roll after a fast ascent and a turning point. This leaves behind distinctive patterns of scalar perturbations, where pre-inflationary peaks can lie well apart from an almost scale invariant profile. I review recent attempts to connect these power spectra to the low-l cosmic microwave background (CMB), and a corresponding one-parameter extension of Lambda cold dark matter (Lambda CDM) with a low-frequency cut Delta. A detailed likelihood analysis led to Delta = (0.351 +/- 0.114) x 10(-3) Mpc(-1), at 99.4% confidence level, in an extended Galactic mask with f(sky) = 39%, to be compared with a nearby value at 88.5% in the standard Planck 2015 mask with f(sky) = 94%. In these scenarios, one would be confronted, in the CMB, with relics of an epoch of deceleration that preceded the onset of slow-roll.

• 出版日期2017-1-10