123,333 research outputs found

    Phenomenological Analysis of pppp and pˉp\bar{p}p Elastic Scattering Data in the Impact Parameter Space

    Full text link
    We use an almost model-independent analytical parameterization for pppp and pˉp\bar{p}p elastic scattering data to analyze the eikonal, profile, and inelastic overlap functions in the impact parameter space. Error propagation in the fit parameters allows estimations of uncertainty regions, improving the geometrical description of the hadron-hadron interaction. Several predictions are shown and, in particular, the prediction for pppp inelastic overlap function at s=14\sqrt{s}=14 TeV shows the saturation of the Froissart-Martin bound at LHC energies.Comment: 15 pages, 16 figure

    The origin of biological macromolecules on the earth. The hypothesis of inorganic template

    Get PDF
    Studies about the origin of life are reviewed. The nonrandom organization of organelles is discussed from a structural and functional point of view. After postulating that the origin of biomacromolecules was not a random event, the paper develops the hypothesis that polypeptides and polynucleotides were formed on an inorganic template. Only information-containing structures can pass natural selection and develop through evolution

    Gamma-Ray Burst Afterglows: Effects of Radiative Corrections and Nonuniformity of the Surrounding Medium

    Get PDF
    The afterglow of a gamma-ray burst (GRB) is commonly thought to be due to continuous deceleration of a relativistically expanding fireball in the surrounding medium. Assuming that the expansion of the fireball is adiabatic and that the density of the medium is a power-law function of shock radius, viz., nextRkn_{ext}\propto R^{-k}, we analytically study the effects of the first-order radiative correction and the nonuniformity of the medium on a GRB afterglow. We first derive a new relation among the observed time, the shock radius and the fireball's Lorentz factor: t=R/4(4k)γ2ct_\oplus=R/4(4-k)\gamma^2c, and also derive a new relation among the comoving time, the shock radius and the fireball's Lorentz factor: tco=2R/(5k)γct_{co}=2R/(5-k)\gamma c. We next study the evolution of the fireball by using the analytic solution of Blandford and McKee (1976). The radiation losses may not significantly influence this evolution. We further derive new scaling laws both between the X-ray flux and observed time and between the optical flux and observed time. We use these scaling laws to discuss the afterglows of GRB 970228 and GRB 970616, and find that if the spectral index of the electron distribution is p=2.5p=2.5, implied from the spectra of GRBs, the X-ray afterglow of GRB970616 is well fitted by assuming k=2k=2.Comment: 17 pages, no figures, Latex file, MNRAS in pres
    corecore