Physics – High Energy Physics – High Energy Physics - Phenomenology
Scientific paper
2007-05-23
JCAP 0708:019,2007
Physics
High Energy Physics
High Energy Physics - Phenomenology
31 pages, 2 figures; v2. refs added
Scientific paper
10.1088/1475-7516/2007/08/019
We study the spectrum, couplings and cosmological and astrophysical implications of the moduli fields for the class of Calabi-Yau IIB string compactifications for which moduli stabilisation leads to an exponentially large volume V ~ 10^{15} l_s^6 and an intermediate string scale m_s ~ 10^{11}GeV, with TeV-scale observable supersymmetry breaking. All K\"ahler moduli except for the overall volume are heavier than the susy breaking scale, with m ~ ln(M_P/m_{3/2}) m_{3/2} ~ (\ln(M_P/m_{3/2}))^2 m_{susy} ~ 500 TeV and, contrary to standard expectations, have matter couplings suppressed only by the string scale rather than the Planck scale. These decay to matter early in the history of the universe, with a reheat temperature T ~ 10^7 GeV, and are free from the cosmological moduli problem (CMP). The heavy moduli have a branching ratio to gravitino pairs of 10^{-30} and do not suffer from the gravitino overproduction problem. The overall volume modulus is a distinctive feature of these models and is an M_{planck}-coupled scalar of mass m ~ 1 MeV and subject to the CMP. A period of thermal inflation can help relax this problem. This field has a lifetime ~ 10^{24}s and can contribute to dark matter. It may be detected through its decays to 2\gamma or e^+e^-. If accessible the e^+e^- decay mode dominates, with Br(\chi \to 2 \gamma) suppressed by a factor (ln(M_P/m_{3/2}))^2. We consider the potential for detection of this field through different astrophysical sources and find that the observed gamma-ray background constrains \Omega_{\chi} <~ 10^{-4}. The decays of this field may generate the 511 keV emission line from the galactic centre observed by INTEGRAL/SPI.
Conlon Joseph P.
Quevedo Fernando
No associations
LandOfFree
Astrophysical and Cosmological Implications of Large Volume String Compactifications does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Astrophysical and Cosmological Implications of Large Volume String Compactifications, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Astrophysical and Cosmological Implications of Large Volume String Compactifications will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-605806