49,044 research outputs found
Suppression of long-wavelength CMB spectrum from the no-boundary initial condition
The lack of correlations at the long-wavelength scales of the cosmic
microwave background spectrum is a long-standing puzzle and it persists in the
latest Planck data. By considering the Hartle-Hawking no-boundary wave function
as the initial condition of the inflationary universe, we propose that the
power suppression can be the consequence of a massive inflaton, whose initial
vacuum is the Euclidean instanton in a compact manifold. We calculate the
primordial power spectrum of the perturbations, and find that as long as the
scalar field is moderately massive, the power spectrum is suppressed at the
long-wavelength scales.Comment: 9 pages, 7 figures; journal versio
Dark information of black hole radiation raised by dark energy
The "lost" information of black hole through the Hawking radiation was
discovered being stored in the correlation among the non-thermally radiated
particles [Phys. Rev. Lett 85, 5042 (2000), Phys. Lett. B 675, 1 (2009)]. This
correlation information, which has not yet been proved locally observable in
principle, is named by dark information. In this paper, we systematically study
the influences of dark energy on black hole radiation, especially on the dark
information. Calculating the radiation spectrum in the existence of dark energy
by the approach of canonical typicality, which is reconfirmed by the quantum
tunneling method, we find that the dark energy will effectively lower the
Hawking temperature, and thus makes the black hole has longer life time. It is
also discovered that the non-thermal effect of the black hole radiation is
enhanced by dark energy so that the dark information of the radiation is
increased. Our observation shows that, besides the mechanical effect (e.g.,
gravitational lensing effect), the dark energy rises the the stored dark
information, which could be probed by a non-local coincidence measurement
similar to the coincidence counting of the Hanbury-Brown -Twiss experiment in
quantum optics.Comment: 21 pages, 3 figures, complete journal-info of Ref.[4] is added,
comments are welcome ([email protected]
QCD corrections to single slepton production at hadron colliders
We evaluate the cross section for single slepton production at hadron
colliders in supersymmetric theories with R-parity violating interactions to
the next-to-leading order in QCD. We obtain fully differential cross section by
using the phase space slicing method. We also perform soft-gluon resummation to
all order in of leading logarithm to obtain a complete transverse
momentum spectrum of the slepton. We find that the full transverse momentum
spectrum is peaked at a few GeV, consistent with the early results for
Drell-Yan production of lepton pairs. We also consider the contribution from
gluon fusion via quark-triangle loop diagrams dominated by the -quark loop.
The cross section of this process is significantly smaller than that of the
tree-level process induced by the initial annihilation.Comment: one new reference is adde
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