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 $z<2$. 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