18,639 research outputs found

    Result on the Mobius Function over Shifted Primes

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    This article provides new asymptotic results for the summatory Mobius function ∑p≀xÎŒ(p+a)=O(x(log⁥x)−c)\sum_{p \leq x} \mu(p+a) =O \left (x(\log x)^{-c} \right ) and the summatory Liouville function ∑p≀xλ(p+a)=O(x(log⁥x)−c)\sum_{p \leq x} \lambda(p+a) =O \left (x(\log x)^{-c} \right ) over the shifted primes, where a≠0a\ne0 is a fixed parameter, and c>1c>1 is an arbitrary constant. These results improve the current estimates ∑p≀xÎŒ(p+a)=(1−ή)π(x)\sum_{p \leq x} \mu(p+a)=(1-\delta)\pi(x), and ∑p≀xλ(p+a)=(1−ή)π(x)\sum_{p \leq x} \lambda(p+a)=(1-\delta)\pi(x) for ÎŽ>0\delta>0, respectively. Furthermore, a conditional proof for the autocorrelation function ∑p≀xÎŒ(p+a)ÎŒ(p+b)=O(x(log⁥x)−c)\sum_{p \leq x} \mu(p+a)\mu(p+b) =O \left (x(\log x)^{-c} \right ), and an unconditional proof for the autocorrelation function ∑p≀xλ(p+a)λ(p+b)=O(x(log⁥x)−c)\sum_{p \leq x} \lambda(p+a)\lambda(p+b) =O \left (x(\log x)^{-c} \right ) over the shifted primes, where a≠ba\ne b, are also included.Comment: Fifty Three Pages. Keywords: Shifted prime; Arithmetic function; Mobius function; Liouville function; vonMangoldt function; Correlation; Autocorrelation; Chowla conjecture; Sarnak conjectur

    QCD Physics with ZEUS and H1 at HERA

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    A review is presented of recent results in QCD from the H1 and ZEUS experiments at HERA, emphasizing the use of higher order calculations to describe the data.Comment: 12 pages, 15 figures, invited review paper for Mod. Phys. Lett

    High-E_T dijet photoproduction at HERA

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    The cross section for high-E_T dijet production in photoproduction has been measured with the ZEUS detector at HERA using an integrated luminosity of 81.8 pb-1. The events were required to have a virtuality of the incoming photon, Q^2, of less than 1 GeV^2 and a photon-proton centre-of-mass energy in the range 142 < W < 293 GeV. Events were selected if at least two jets satisfied the transverse-energy requirements of E_T(jet1) > 20 GeV and E_T(jet2) > 15 GeV and pseudorapidity requirements of -1 < eta(jet1,2) < 3, with at least one of the jets satisfying -1 < eta(jet) < 2.5. The measurements show sensitivity to the parton distributions in the photon and proton and effects beyond next-to-leading order in QCD. Hence these data can be used to constrain further the parton densities in the proton and photon.Comment: 36 pages, 13 figures, 20 tables, including minor revisions from referees. Accepted by Phys. Rev.

    A probability-conserving cross-section biasing mechanism for variance reduction in Monte Carlo particle transport calculations

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    In Monte Carlo particle transport codes, it is often important to adjust reaction cross sections to reduce the variance of calculations of relatively rare events, in a technique known as non-analogous Monte Carlo. We present the theory and sample code for a Geant4 process which allows the cross section of a G4VDiscreteProcess to be scaled, while adjusting track weights so as to mitigate the effects of altered primary beam depletion induced by the cross section change. This makes it possible to increase the cross section of nuclear reactions by factors exceeding 10^4 (in appropriate cases), without distorting the results of energy deposition calculations or coincidence rates. The procedure is also valid for bias factors less than unity, which is useful, for example, in problems that involve computation of particle penetration deep into a target, such as occurs in atmospheric showers or in shielding
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