Common and private property to exhaustible resources: theoretical implications for economic growth

We develop two models of economic growth with exhaustible natural resources and consumers heterogeneous in time preferences. The first model assumes private ownership of natural resources. In the second model, natural resources are commonly owned and the resource extraction rate is chosen by voting. We show that if discount factors are given exogenously, the long-run rate of growth under private property is higher than or equal to that under common property. If the discount factors are formed endogenously, under some circumstances common property can result in a higher rate of growth than private property.natural resources, economic growth, voting, private property, common property

Relative rates of B meson decays into psi(2S) and J/psi mesons

We report on a study of the relative rates of B meson decays into psi(2S) and J/psi mesons using 1.3 fb^-1 of pbar p collisions at sqrt(s) = 1.96 TeV recorded by the D0 detector operating at the Fermilab Tevatron Collider. We observe the channels B^0_s -> psi(2S)phi, B^0_s -> J/psi phi, B^+/- -> psi(2S) K^+/-, and B^+/- -> J/psi K^+/- and we measure the relative branching fractions for these channels to be B(B^0_s -> psi(2S)phi)/B(B^0_s -> J/psi phi) = 0.55 +/- 0.11 (stat) +/- 0.07 (syst) +/- 0.06 (B), B(B^+/- -> psi(2S) K^+/-)/B(B^+/- -> J/psi K^+/-) = 0.65 +/- 0.04 (stat) +/- 0.03 (syst) +/- 0.07 (B) where the final error corresponds to the uncertainty in the J/psi and psi(2S) branching ratio into two muons

Measurement of the inclusive jet cross section in ppˉp \bar{p} collisions at s=1.96TeV\sqrt{s}=1.96 {\rm TeV}

We report on a measurement of the inclusive jet cross section in $p \bar{p}$ collisions at a center-of-mass energy $\sqrt s=$1.96 TeV using data collected by the D0 experiment at the Fermilab Tevatron Collider corresponding to an integrated luminosity of 0.70 fb$^{-1}$. The data cover jet transverse momenta from 50 GeV to 600 GeV and jet rapidities in the range -2.4 to 2.4. Detailed studies of correlations between systematic uncertainties in transverse momentum and rapidity are presented, and the cross section measurements are found to be in good agreement with next-to-leading order QCD calculations

Search for Large extra spatial dimensions in the dielectron and diphoton channels in ppˉ\bm{p\bar{p}} collisions at s=\bm{\sqrt{s}=}1.96 TeV

We report on a search for large extra spatial dimensions in the dielectron and diphoton channels using a data sample of 1.05 \invfb of \ppb collisions at a center-of-mass energy of 1.96 TeV collected by the D0 detector at the Fermilab Tevatron Collider. The invariant mass spectrum of the data agrees well with the prediction of the standard model. We find 95% C.L. lower limits on the effective Planck scale between 2.1 and 1.3 TeV for 2 to 7 extra dimensions

Quantum gravity and the standard model

We show that a class of background independent models of quantum spacetime have local excitations that can be mapped to the first generation fermions of the standard model of particle physics. These states propagate coherently as they can be shown to be noiseless subsystems of the microscopic quantum dynamics. These are identified in terms of certain patterns of braiding of graphs, thus giving a quantum gravitational foundation for the topological preon model proposed by one of us. These results apply to a large class of theories in which the Hilbert space has a basis of states given by ribbon graphs embedded in a three-dimensional manifold up to diffeomorphisms, and the dynamics is given by local moves on the graphs, such as arise in the representation theory of quantum groups. For such models, matter appears to be already included in the microscopic kinematics and dynamics.Comment: 12 pages, 21 figures, improved presentation, results unchange

Tvrda ekskluzivna elektrotvorba rezonantnih i nerezonantnih parova piona u HERMESu

A selection of recent HERMES results is presented on the hard exclusive electroproduction of resonant and non-resonant π +π − pairs. The ratio of ρ 0 electroproduction cross sections per nucleon on 14N as compared to that on 1H, known as the nuclear transparency, was found to increase (decrease) with increasing coherence length for coherent (incoherent) ρ 0 electroproduction. For a fixed coherence length, a rise of the nuclear transparency with Q2 is observed for both coherent and incoherent ρ 0 production, which is in agreement with theoretical calculations that include the effect of color transparency. The first-order intensity density for exclusive electroproduction of π +π − pairs has been studied as a function of the invariant mass Mππ in the range 0.3 < Mπ+π− < 1.5 GeV. The derived quantities show a dependence of the π +π − invariant mass, which can be understood as due to the interference between pion pairs in relative P-wave (isovector channel) and S,D-waves (isoscalar channel) states.Predstavljamo odabir ishoda nedavnih mjerenja tvrde ekskluzivne elektrotvorbe rezonantnih i nerezonantnih parova π +π −. Nalazimo da omjer udarnih presjeka elektrotvorbe ρ 0 po nukleonu u 14N i 1H, poznat kao nuklearna prozirnost, raste (opada) s povećanjem koherentne duljine za koherentnu (nekoherentnu) elektrotvorbu. Za određenu koherentnu duljinu, opaža se porast sa Q2 za koherentnu kao i za nekoherentnu tvorbu ρ 0 , što je u skladu s teorijskim računima koji uključuju učinke prozirnosti boje. Proučavali smo gustoću intenziteta za ekskluzivnu elektrotvorbu parova π +π − u prvom redu, kao funkciju invarijantne mase Mππ u području 0.3 < Mπ+π− < 1.5 GeV. Izvedene veličine pokazuju ovisnost invarijantne mase π +π −, što se može shvatiti posljedicom interferencije među pionskim parovima u relativnim P-valnim (izovektorski kanal) i S,D-valnim stanjima (izoskalarni kanal)

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Measurement of the production of a W boson in association with a charm quark in pp collisions at √s = 7 TeV with the ATLAS detector

The production of a W boson in association with a single charm quark is studied using 4.6 fb−1 of pp collision data at s√ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26−0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W + +c¯¯)/σ(W − + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s−s¯¯¯ quark asymmetry