4,424 research outputs found
Is the Dark Disc contribution to Dark Matter Signals important ?
Recent N-body simulations indicate that a thick disc of dark matter,
co-rotating with the stellar disc, forms in a galactic halo after a merger at a
redshift . The existence of such a dark disc component in the Milky Way
could affect dramatically dark matter signals in direct and indirect detection.
In this letter, we discuss the possible signal enhancement in connection with
the characteristics of the local velocity distributions. We argue that the
enhancement is rather mild, but some subtle effects may arise. In particular,
the annual modulation observed by DAMA becomes less constrained by other direct
detection experiments
Binary mixture of hard disks as a model glass former: Caging and uncaging
I have proposed a measure for the cage effect in glass forming systems. A
binary mixture of hard disks is numerically studied as a model glass former. A
network is constructed on the basis of the colliding pairs of disks. A rigidity
matrix is formed from the isostatic (rigid) sub--network, corresponding to a
cage. The determinant of the matrix changes its sign when an uncaging event
occurs. Time evolution of the number of the uncaging events is determined
numerically. I have found that there is a gap in the uncaging timescales
between the cages involving different numbers of disks. Caging of one disk by
two neighboring disks sustains for a longer time as compared with other cages
involving more than one disk. This gap causes two--step relaxation of this
system
A Dual Geometry of the Hadron in Dense Matter
We identify the dual geometry of the hadron phase of dense nuclear matter and
investigate the confinement/deconfinement phase transition. We suggest that the
low temperature phase of the RN black hole with the full backreaction of the
bulk gauge field is described by the zero mass limit of the RN black hole with
hard wall. We calculated the density dependence of critical temperature and
found that the phase diagram closes. We also study the density dependence of
the rho meson mass.Comment: 16 pages, 4 figures, typos corrected, references adde
Photo-emission rate of sQGP at finite density
We calculate the thermal spectral function of SYM plasma with finite density
using holographic technique. We take the RN-AdS black hole as the dual gravity
theory. In the presence of charge, vector modes of gravitational and
electromagnetic perturbation are coupled with each other. By introducing master
variables for these modes, we solve the coupled system and calculate spectral
function. We also calculated photoemission rate of SYM plasma from spectral
function for light like momentum, AC conductivity and their density dependence.
The suppression of the conductivity in high density is noticed, which might be
yet another mechanism for the Jet quenching phenomena in RHIC experiment.Comment: 27 pages, 10 figure
Resolving the personalization-privacy dilemma: theory and implications of a privacy-preserving contract
Working papers seriesPersonalization is an integral part of e-commerce strategy today. A unique feature of personalization is that it requires users to provide a certain amount of personal information to the service provider, thus giving rise to an interesting dilemma in that consumers cannot enjoy more personalized services without sacrificing more privacy. In this paper, we propose a mechanism that allows an online personalization vendor to provide proper incentives for consumers to share information, while protecting their privacy at the same time. The proposed solution not only enables consumers and the firm to engage in an otherwise unviable market, but it also allows the firm to implement an incentive-compatible menu that serves all consumers regardless of their privacy sensitivity. Further, we demonstrate that a minimum privacy-preservation policy is an effective device for protecting consumers’ online privacy, and that it outperforms restricting vendors’ ability in collecting customer information.
Our proposed mechanism is of theoretical and practical importance: By transforming the compensation schedule (privacy preservation) into a set-compliment device to the production variable, our approach offers an alternative to the reliance on external transfer, thus eradicating a major constraint confronted by traditional mechanism design. Practically, our research proposes a realistic, easily-implementable solution to the fervent calls for endowing consumers with greater control over their online privacy. Further, it offers important policy guidelines to the regulator on not only what devices can be applied in governing the information practice of online vendors, but also exactly how social-efficiency can be enhanced.preprin
Probing Majorana neutrinos in rare K and D, D_s, B, B_c meson decays
We study lepton number violating decays of charged K, D, D_s, B and B_c
mesons of the form M^+\to {M'}^-\ell^+\ell^+, induced by the existence of
Majorana neutrinos. These processes provide information complementary to
neutrinoless double nuclear beta decays, and are sensitive to neutrino masses
and lepton mixing. We explore neutrino mass ranges m_N from below 1 eV to
several hundred GeV. We find that in many cases the branching ratios are
prohibitively small, however in the intermediate range m_\pi < m_N < m_{B_c},
in specific channels and for specific neutrino masses, the branching ratios can
be at the reach of high luminosity experiments like those at the LHC-b and
future Super flavor-factories, and can provide bounds on the lepton mixing
parameters.Comment: 25 page
The Fiscal Multiplier in a Liquidity Constrained New Keynesian Economy
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.We study the effects of fiscal policy on the macroeconomy using a liquidity constrained New Keynesian model in which government bonds are liquid and private financial assets are only partially liquid. We find that the fiscal multipliers in this economic environment are large enough for fiscal policy to be highly effective. In this model, a bond-financed fiscal expansion can stimulate output since higher public borrowing improves liquidity by increasing the proportion of liquid assets in private-sector wealth
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