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Superstring theory is the unique candidate for the complete unified theory of Nature (the Ultimate Theory) at present. However, we have not succeeded in predicting the values of the fundamental parameters of low energy physics or in deriving a consistent inflationary universe model from superstring theory, because we do not know the compactification and stabilisation mechanism. One promising approach to elucidate this compactification mechanism is to explore both theoretically and experimentally various characteristic phenomena in laboratories and cosmophysics provoked by hidden sector particles and fields that are inevitably produced by compactification.

  From this perspective, in this workshop, we overview promising hidden sector particle/field phenomena and on-going and future experiments/observations to probe them and discuss their potential implications to the theoretical challenge to construct compactification of string theory that are consistent both with particle experiments and cosmophysical observations. The workshop will consist of invited review talks and contributed talks. Talks on new theoretical and experimental proposals are welcome.


Topics to be discussed

  • Moduli stabilisation vs inflation in string compactification
  • String phenomenology and hidden sector particles/fields
  • Axions, relaxions and moduli cosmology
  • Black holes with invisible hairs/clouds and GW emissions
  • Laboratory experiments to detect hidden sector particles
  • Future CMB anisotropy/spectroscopy observation experiments
  • 21cm/radio observations, pulsar timing observations
  • Hidden sector search and fundamental sciences by gravitational waves

Invited Speakers

  • Asimina Arvanitaki (Perimeter Inst)
  • Carlos A. R. Herdeiro (U Aveiro)
  • Ralph Blumenhagen (MPIfP)
  • Joseph Conlon (Oxford U)
  • Jens Chluba (U of Manchester)
  • Yoshizumi Inoue (U Tokyo)
  • Jonah Kanner ( Caltech)
  • David J. E. Marsh (King’s College London)
  • Yuto Minami (KEK)
  • Natsumi Nagata (U Tokyo)
  • Andreas Ringwald (DESY)
  • Takahiro Tanaka (Kyoto U)
  • Hirotaka Yoshino (Osaka City U)

As of Nov. 11, 2016


Tetsutaro Higaki (Keio U)
Kunihito Ioka (YITP)
Masahiro Kawasaki (ICRR, U Tokyo)
Tatsuo Kobayashi (Hokkaido U)
Hideo Kodama (YITP, Chair)
Kazunori Kohri (KEK)
Shun'ya Mizoguchi (KEK)
Kazunori Nakayama (U Tokyo)
Jiro Soda (Kobe U)
Fuminobu Takahashi (Tohoku U)
Jun'ichi Yokoyama (RESCEU, U Tokyo)
Hirotaka Yoshino (KEK)

LOC & Contact

Hideo Kodama (Chair)
Kunihito Ioka

Contact address:
Secretary: Ms. Kuniko Tsuruhara
Yukawa Institute for Theoretical Physics, Kyoto University
Oiwakecho, Kitashirakawa, Sakyoku, Kyoto 606-8502, Japan


    This workshop is supported by the Yukawa Institute for Theoretical Physics and the JSPS Grant-in-Aid for Scientific Research (A) 26247042
    "Quest for the Ultimate Theory in terms of rich cosmophysical phenomena caused by fields and particles in the hidden sector".

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