1,778 research outputs found

    Formation spectra of light kaonic nuclei by in-flight (Kˉ,N{\bar K},N) reactions with chiral unitary amplitude

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    We study theoretically the in-flight (K,NK^-,N) reactions for the formation of light kaonic nuclear systems to get deeper physical insights on the expected spectra, and to investigate the experimental feasibility of the reaction at new facilities like J-PARC. We show the expected spectra for the formation of the Kpp,KpnK^-pp, K^-pn, KnnK^-nn and KK^--11^{11}B systems which are accessible by the (K,NK^-,N) experiments. By considering the conversion part of the Green's function, we can show the missing mass spectra of the (K,NK^-,N) reactions coincidence with the particle emissions due to Kˉ{\bar K} absorption in KˉNπY{\bar K}N\to \pi Y processes. To calculate the cross sections, we use the so-called TρT\rho approximation to evaluate the optical potential. As for the amplitude TT, we adopt the chiral unitary amplitude of KˉN{\bar K}N channel in vacuum for simplicity, and we also check the medium effects by applying the chiral amplitude at finite density. The effects of the p-wave optical potential of Σ\Sigma(1385) channel and the contribution from Kˉ0{\bar K^0} mixing in 3^3He(K,nK^-,n) reaction are also evaluated numerically. To understand the meanings of the spectrum shape, we also study the behavior of the poles of kaon Green's function in nuclear matter. We conclude that 3^3He(K,nK^-,n) and 3^3He(K,pK^-,p) reactions coincident with the πΣ\pi\Sigma emission due to Kˉ{\bar K} absorption may show the certain structure in the bound region spectra indicating the existence of the unstable kaonic nuclear bound states. As for the 12^{12}C(K,pK^-,p) spectra with the πΣ\pi\Sigma emission, we may also observe the structure in the bound region, however, we need to evaluate the medium effects carefully for larger nuclei.Comment: 14 pages, 12 figure

    Operational Semantics of Process Monitors

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    CSPe is a specification language for runtime monitors that can directly express concurrency in a bottom-up manner that composes the system from simpler, interacting components. It includes constructs to explicitly flag failures to the monitor, which unlike deadlocks and livelocks in conventional process algebras, propagate globally and aborts the whole system's execution. Although CSPe has a trace semantics along with an implementation demonstrating acceptable performance, it lacks an operational semantics. An operational semantics is not only more accessible than trace semantics but also indispensable for ensuring the correctness of the implementation. Furthermore, a process algebra like CSPe admits multiple denotational semantics appropriate for different purposes, and an operational semantics is the basis for justifying such semantics' integrity and relevance. In this paper, we develop an SOS-style operational semantics for CSPe, which properly accounts for explicit failures and will serve as a basis for further study of its properties, its optimization, and its use in runtime verification

    Interfacial adsorption phenomena of the three-dimensional three-state Potts model

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    We study the interfacial adsorption phenomena of the three-state ferromagnetic Potts model on the simple cubic lattice by the Monte Carlo method. Finite-size scaling analyses of the net-adsorption yield the evidence of the phase transition being of first-order and kBTC/J=1.8166(2)k_{\rm B} T_{\rm C} / J = 1.8166 (2).Comment: 14 page

    The high-lying 6^6Li levels at excitation energy around 21 MeV

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    The 3^3H+3^3He cluster structure in 6^6Li was investigated by the 3^3H(α\alpha,3^3H 3^3He)n kinematically complete experiment at the incident energy EαE_\alpha = 67.2 MeV. We have observed two resonances at ExE_x^* = 21.30 and 21.90 MeV which are consistent with the 3^3He(3^3H, γ\gamma)6^6Li analysis in the Ajzenberg-Selove compilation. Our data are compared with the previous experimental data and the RGM and CSRGM calculations.Comment: 12 pages, 6 figures. Accepted for publication in J. Phys. Soc. Jp

    Numerical Latent Heat Observation of the q=5 Potts Model

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    Site energy of the five-state ferromagnetic Potts model is numerically calculated at the first-order transition temperature using corner transfer matrix renormalization group (CTMRG) method. The calculated energy of the disordered phase U+U^{+} is clearly different from that of the ordered phase UU^{-}. The obtained latent heat L=UU+L = U^{-} - U^{+} is 0.027, which quantitatively agrees with the exact solution.Comment: 2 pages, Latex(JPSJ style files are included), 2 ps figures, submitted to J. Phys. Soc. Jpn.(short note

    The envelope of IRC+10216 reflecting the galactic light: UBV surface brightness photometry and interpretation

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    We present and analyse new optical images of the dust envelope surrounding the high mass-loss carbon star IRC+10216. This envelope is seen due to external illumination by galactic light. Intensity profiles and colors of the nebula were obtained in the UBV bandpasses. The data are compared with the results of a radiative transfer model calculating multiple scattering of interstellar field photons by dust grains with a single radius. The data show that the observed radial shape of the nebula, especially its half maximum radius, does not depend on wavelength (within experimental errors), suggesting that grains scatter in the grey regime, etc, etc (this abstract has been shortened)Comment: accepted by A

    Constraints on the SU(3) Electroweak Model

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    We consider a recent proposal by Dimopoulos and Kaplan to embed the electroweak SU(2)_L X U(1)_Y into a larger group SU(3)_W X SU(2) X U(1) at a scale above a TeV. This idea is motivated by the prediction for the weak mixing angle sin^2 theta_W = 1/4, which naturally appears in these models so long as the gauge couplings of the high energy SU(2) and U(1) groups are moderately large. The extended gauge dynamics results in new effective operators that contribute to four-fermion interactions and Z pole observables. We calculate the corrections to these electroweak precision observables and carry out a global fit of the new physics to the data. For SU(2) and U(1) gauge couplings larger than 1, we find that the 95% C.L. lower bound on the matching (heavy gauge boson mass) scale is 11 TeV. We comment on the fine-tuning of the high energy gauge couplings needed to allow matching scales above our bounds. The remnants of SU(3)_W breaking include multi-TeV SU(2)_L doublets with electric charge (+-2,+-1). The lightest charged gauge boson is stable, leading to cosmological difficulties.Comment: 17 pages, LaTeX, 4 figures embedded, uses JHEP.cl

    Boundary and Bulk Phase Transitions in the Two Dimensional Q > 4 State Potts Model

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    The surface and bulk properties of the two-dimensional Q > 4 state Potts model in the vicinity of the first order bulk transition point have been studied by exact calculations and by density matrix renormalization group techniques. For the surface transition the complete analytical solution of the problem is presented in the QQ \to \infty limit, including the critical and tricritical exponents, magnetization profiles and scaling functions. According to the accurate numerical results the universality class of the surface transition is independent of the value of Q > 4. For the bulk transition we have numerically calculated the latent heat and the magnetization discontinuity and we have shown that the correlation lengths in the ordered and in the disordered phases are identical at the transition point.Comment: 11 pages, RevTeX, 6 PostScript figures included. Manuscript substantially extended, details on the analytical and numerical calculations added. To appear in Phys. Rev.

    ESO Imaging Survey. The Stellar Catalogue in the Chandra Deep Field South

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    (abridged) Stellar catalogues in five passbands (UBVRI) over an area of approximately 0.3 deg^2, comprising about 1200 objects, and in seven passbands (UBVRIJK) over approximately 0.1 deg^2, comprising about 400 objects, in the direction of the Chandra Deep Field South are presented. The 90% completeness level of the number counts is reached at approximately U = 23.8, B = 24.0, V = 23.5, R = 23.0, I = 21.0, J = 20.5, K = 19.0. A scheme is presented to select point sources from these catalogues, by combining the SExtractor parameter CLASS_STAR from all available passbands. Probable QSOs and unresolved galaxies are identified by using the previously developed \chi^2-technique (Hatziminaoglou et al 2002), that fits the overall spectral energy distributions to template spectra and determines the best fitting template. The observed number counts, colour-magnitude diagrams, colour-colour diagrams and colour distributions are presented and, to judge the quality of the data, compared to simulations based on the predictions of a Galactic Model convolved with the estimated completeness functions and the error model used to describe the photometric errors of the data. The resulting stellar catalogues and the objects identified as likely QSOs and unresolved galaxies with coordinates, observed magnitudes with errors and assigned spectral types by the χ2\chi^2-technique are presented and are publicly available.Comment: Paper as it will appear in print. Complete figures and tables can be obtained from: http://www.eso.org/science/eis/eis_pub/eis_pub.html. Astronomy & Astrophysics, accepted for publicatio

    Universal Short-Time Dynamics in the Kosterlitz-Thouless Phase

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    We study the short-time dynamics of systems that develop ``quasi long-range order'' after a quench to the Kosterlitz-Thouless phase. With the working hypothesis that the ``universal short-time behavior'', previously found in Ising-like systems, also occurs in the Kosterlitz-Thouless phase, we explore the scaling behavior of thermodynamic variables during the relaxational process following the quench. As a concrete example, we investigate the two-dimensional 66-state clock model by Monte Carlo simulation. The exponents governing the magnetization, the second moment, and the autocorrelation function are calculated. From them, by means of scaling relations, estimates for the equilibrium exponents zz and η\eta are derived. In particular, our estimates for the temperature-dependent anomalous dimension η\eta that governs the static correlation function are consistent with existing analytical and numerical results and, thus, confirm our working hypothesis.Comment: 16 pages, 9 postscript figures, REVTEX 3.0, submitted to Phys. Rev.
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