Strange quark suppression from a simultaneous Monte Carlo analysis of parton distributions and fragmentation functions

We perform the first simultaneous extraction of unpolarized parton distributions and fragmentation functions from a Monte Carlo analysis of inclusive and semi-inclusive deep-inelastic scattering, Drell-Yan lepton-pair production, and single-inclusive $e^+ e^-$ annihilation data. We use data resampling techniques to thoroughly explore the Bayesian posterior distribution of the extracted functions, and use $k$-means clustering on the parameter samples to identify the configurations that give the best description across all reactions. Inclusion of the semi-inclusive data reveals a strong suppression of the strange quark distribution at parton momentum fractions $x \gtrsim 0.01$, in contrast with the ATLAS observation of enhanced strangeness in $W^\pm$ and $Z$ production at the LHC. Our study reveals significant correlations between the strange quark density and the strange $\to$ kaon fragmentation function needed to simultaneously describe semi-inclusive $K^\pm$ production data from COMPASS and inclusive $K^\pm$ spectra in $e^+ e^-$ annihilation from ALEPH and SLD, as well as between the strange and light antiquark densities in the proton.Comment: 6 pages, 4 figures; version to appear in Phys. Rev.

Towards a Comprehensive Fueling-Controlled Theory on the Growth of Massive Black Holes and Host Spheroids

We study the relation between nuclear massive black holes and their host spheroid gravitational potential. Using AMR numerical simulations, we analyze how gas is transported in the nuclear (central kpc) regions of galaxies. We study the gas fueling onto the inner accretion disk (sub-pc scale) and the star formation in a massive nuclear disk like those generally found in proto-spheroids (ULIRGs, SCUBA Galaxies). These sub-pc resolution simulation of gas fueling that is mainly depleted by star formation naturally satisfy the `M_BH - $M_virial' relation, with a scatter considerably less than the observed one. We found a generalized version of Kennicutt-Schmidt Law for starbursts is satisfied, in which the total gas depletion rate (dot{M}_gas = dot{M}_BH + dot{M}_SF) is the one that scales as M_gas/t_orbital. We also found that the `M_BH - sigma' relation is a byproduct of the `M_BH - M_virial' relation in the fueling controlled scenario.Comment: 12 pages, figures, submited to ApJ, email: [email protected]

Ab-initio molecular dynamics simulation of hydrogen diffusion in α\alpha-iron

First-principles atomistic molecular dynamics simulation in the micro-canonical and canonical ensembles has been used to study the diffusion of interstitial hydrogen in $\alpha$-iron. Hydrogen to Iron ratios between $\theta=1/16 and 1/2 have been considered by locating interstitial hydrogen atoms at random positions in a$2 \times 2 \times 2$ supercell. We find that the average optimum absorption site and the barrier for diffusion depend on the concentration of interestitials. Iron Debye temperature decreases monotonically for increasing concentration of interstitial hydrogen, proving that iron-iron interatomic potential is significantly weakened in the presence of a large number of diffusing hydrogen atoms

Health benefits and uncertainty: an experimental analysis of the effects of risk presentation on auction bids for a healthful product

Experimental subjects receive a different presentation of a food product's potential health risk reductions if eaten regularly. They are then asked to bid for the product. Results suggest that the bids vary across the groups that receive differing risk information.

Health Benefits and Uncertainty: An Experimental Analysis of the Effects of Risk Presentation on Auction Bids for a Healthful Product

Experimental subjects receive a different presentation of a food product's potential health risk reductions if people habitually eat it, and then asked to bid for the product. Results suggest that the bids vary across the groups that receive differing risk information.Health risks, experimental economics, auctions, uncertainty, Risk and Uncertainty, D81, I12,

The Effect of Risk Presentation on Product Valuation: An Experimental Analysis

We examine how people might evaluate a product with novel attribute, given various kinds of risk information. Using a product with healthful benefits, we assess subjects' willingness to pay given various kinds of health risk information conveying reduced health risks, life tradeoffs, and ambiguity. Four treatments in separate non-hypothetical experimental auctions are used to elicit willingness to pay values. Results suggest that willingness to pay vary across the groups that receive differing risk information. Specifically, willingness to pay was higher for the group that was given clear risk information and questions related to life tradeoffs than for the group given ambiguous risk information. Willingness to pay was lowest for the group that was given no risk information at all.Risk and Uncertainty,