1,676 research outputs found

    Deconfinement transition and string tensions in SU(4) Yang-Mills Theory

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    We present results from numerical lattice calculations of SU(4) Yang-Mills theory. This work has two goals: to determine the order of the finite temperature deconfinement transition on an Nt=6N_t = 6 lattice and to study the string tensions between static charges in the irreducible representations of SU(4). Motivated by Pisarski and Tytgat's argument that a second-order SU(∞\infty) deconfinement transition would explain some features of the SU(3) and QCD transitions, we confirm older results on a coarser, Nt=4N_t = 4, lattice. We see a clear two-phase coexistence signal, characteristic of a first-order transition, at 8/g2=10.798/g^2 = 10.79 on a 6×2036\times 20^3 lattice, on which we also compute a latent heat of Δϵ≈0.6ϵSB\Delta\epsilon\approx 0.6 \epsilon_{SB}. Computing Polyakov loop correlation functions we calculate the string tension at finite temperature in the confined phase between fundamental charges, σ1\sigma_1, between diquark charges, σ2\sigma_2, and between adjoint charges σ4\sigma_4. We find that 1<σ2/σ1<21 < \sigma_2/\sigma_1 < 2, and our result for the adjoint string tension σ4\sigma_4 is consistent with string breaking.Comment: 10 pages with included figures. For version 2: New calculation and discussion of latent heat added; 2 new figures and 1 new table. Typo in abstract corrected for v3. To appear in Physical Review

    Particle Production on Half S-brane

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    In this paper we will study quantum field theory of fluctuation modes around the rolling tachyon solution on non-BPS D-brane effective action. The goal of this paper is to study particle production during the decay of non-BPS D-brane and explore possible relation with minisuperspace calculation. We find that the number of particles produced on half S-brane exponentially grows for large time which suggests that linearised approximation breaks down and also that backreaction of fluctuation field on classical solution should be taken into account.Comment: 24 pages,v1.references adde

    The all-particle spectrum of primary cosmic rays in the wide energy range from 10^14 eV to 10^17 eV observed with the Tibet-III air-shower array

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    We present an updated all-particle energy spectrum of primary cosmic rays in a wide range from 10^14 eV to 10^17 eV using 5.5 times 10^7 events collected in the period from 2000 November through 2004 October by the Tibet-III air-shower array located at 4300 m above sea level (atmospheric depth of 606 g/cm^2). The size spectrum exhibits a sharp knee at a corresponding primary energy around 4 PeV. This work uses increased statistics and new simulation calculations for the analysis. We performed extensive Monte Carlo calculations and discuss the model dependences involved in the final result assuming interaction models of QGSJET01c and SIBYLL2.1 and primary composition models of heavy dominant (HD) and proton dominant (PD) ones. Pure proton and pure iron primary models are also examined as extreme cases. The detector simulation was also made to improve the accuracy of determining the size of the air showers and the energy of the primary particle. We confirmed that the all-particle energy spectra obtained under various plausible model parameters are not significantly different from each other as expected from the characteristics of the experiment at the high altitude, where the air showers of the primary energy around the knee reaches near maximum development and their features are dominated by electromagnetic components leading to the weak dependence on the interaction model or the primary mass. This is the highest-statistical and the best systematics-controlled measurement covering the widest energy range around the knee energy region.Comment: 19 pages, 20 figures, accepted by Ap
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