4,682 research outputs found

    d-Au and p-p collisions at RHIC and the multichain Monte Carlo Dpmjet-III

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    In this paper we compare systematically the two-component Dual Parton Model (DPM) event generator Dpmjet-III to d-Au and p-p data from RHIC. In this process we are able to improve the model. The need for fusion of chains and a recalibration of the model to obtain collision scaling in h-A and d-A collisions was found already in previous comparisons. Here, comparing to transverse momentum distributions of identified charged hadrons we find also the need to modify the transverse momentum distributions in the decay of hadronic strings, the basic building blocks of the model on soft hadronic collisions.Comment: 8 pages, 13 figures, Based on a contribution to a workshop "QCD at Cosmic Energies, Erice, Italie, Aug.29 to Sept.5 200

    The Functional Transformation Buildings in The Old City Semarang Based on The Urban Sustainable-Conservation Concepts

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    Conservation and Sustainability are inspiring the region of the Old City in Semarang. As the meanings of both words, the aim of conservation and sustainability in this region is addressed to secure long-term harmony between man and nature, to achieve continuous enhancement in the environment, and to increase the quality of life for humans and other life forms. Several buildings in the Old City Semarang show sustainability in how they interacts with people and public activities. The buildings change into public facilities that serves people in daily public activities. The transformations of their functions are very closed to society. This paper discusses cases on term how the buildings secure their conservation and sustainability by statistical methods and descriptive analyses. Respondents had been taken from customers who visited to the buildings. The results show that certain buildings have a better maintenance than others as public facilities. Moreover, the greater the interaction of buildings and public activities, the better the maintenances have been represented by the building

    Partial wave analysis of J/psi to p pbar pi0

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    Using a sample of 58 million J/ψJ/\psi events collected with the BESII detector at the BEPC, more than 100,000 J/ψ→ppˉπ0J/\psi \to p\bar p \pi^0 events are selected, and a detailed partial wave analysis is performed. The branching fraction is determined to be Br(J/ψ→ppˉπ0)=(1.33±0.02±0.11)×10−3Br(J/\psi \to p \bar p \pi^0)=(1.33 \pm 0.02 \pm 0.11) \times 10^{-3}. A long-sought `missing' N∗N^*, first observed in J/ψ→pnˉπ−J/\psi \to p \bar n \pi^-, is observed in this decay too, with mass and width of 2040−4+3±252040_{-4}^{+3}\pm 25 MeV/c2^2 and 230−8+8±52230_{-8}^{+8}\pm 52 MeV/c2^2, respectively. Its spin-parity favors 3/2+{3/2}^+. The masses, widths, and spin-parities of other N∗N^* states are obtained as well.Comment: Add one author nam

    High-energy emission from jet-cloud interactions in AGNs

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    Active galactic nuclei present continuum and line emission. The emission lines are originated by gas located close to the central super-massive black hole. Some of these lines are broad, and would be produced in a small region called broad-line region. This region could be formed by clouds surrounding the central black hole. In this work, we study the interaction of such clouds with the base of the jets in active galactic nuclei, and we compute the produced high-energy emission. We focus on sources with low luminosities in the inner jet regions, to avoid strong gamma-ray absorption. We find that the resulting high-energy radiation may be significant in Centaurus A. Also, this phenomenon might be behind the variable gamma-ray emission detected in M87, if very large dark clouds are present. The detection of jet-cloud interactions in active galactic nuclei would give information on the properties of the jet base and the very central regions.Comment: 6 pages, 3 figures. To appear in the proceeding of the conference: "High Energy Phenomena in Relativistic Outflows (HEPRO) II", held in Buenos Aires, Argentina, October 26-30 2009

    Ξ−\Xi^{-} and Ξˉ+\bar{\Xi}^{+} baryon production in Au+Au collisions at sNN=130\sqrt{s_{NN}}=130 GeV

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    We report preliminary results on the centrality dependence of the Ξ−\Xi^{-} and Ξˉ+\bar{\Xi}^{+} production at mid-rapidity in sNN=130\sqrt{s_{NN}}=130 GeV Au+Au collisions from the STAR experiment. For the most central data the obtained yields suggest a saturation of strangeness production per produced hadron. The calculated inverse slope parameter may indicate an earlier freeze-out of these particles.Comment: 4 pages, 3 figures, 1 table, Contribution to Quark Matter 2002, Nantes, France, July 200

    New experimental limit on Pauli Exclusion Principle violation by electrons (the VIP experiment)

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    The Pauli Exclusion Principle is one of the basic principles of modern physics and is at the very basis of our understanding of matter: thus it is fundamental importance to test the limits of its validity. Here we present the VIP (Violation of the Pauli Exclusion Principle) experiment, where we search for anomalous X-rays emitted by copper atoms in a conductor: any detection of these anomalous X-rays would mark a Pauli-forbidden transition. ] VIP is currently taking data at the Gran Sasso underground laboratories, and its scientific goal is to improve by at least four orders of magnitude the previous limit on the probability of Pauli violating transitions, bringing it into the 10**-29 - 10**-30 region. First experimental results, together with future plans, are presented.Comment: To appear in proceedings of the XLVI International Winter Meeting on Nuclear Physics, Bormio, Italy, January 20-26, 200

    New experimental limit on Pauli Exclusion Principle violation by electrons (the VIP experiment)

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    The Pauli exclusion principle (PEP) represents one of the basic principles of modern physics and, even if there are no compelling reasons to doubt its validity, it still spurs a lively debate, because an intuitive, elementary explanation is still missing, and because of its unique stand among the basic symmetries of physics. A new limit on the probability that PEP is violated by electrons was estabilished by the VIP (VIolation of the Pauli exclusion principle) Collaboration, using the method of searching for PEP forbidden atomic transitions in copper. The preliminary value, {1/2}\beta^{2} \textless 4.5\times 10^{-28}, represents an improvement of about two orders of magnitude of the previous limit. The goal of VIP is to push this limit at the level of 10−3010^{-30}.Comment: submitted to Journal of Physics: Conference Series, by the Institute of Physic

    Ultra High Energy Tau Neutrinos and Fluorescence Detectors: A Phenomenological Approach

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    We investigate the possibility of detecting ultra-high energy cosmic tau-neutrinos by means of a process involving a double extensive air shower, the so-called Double-Bang Phenomenon. In this process a primary tau-neutrino interacts with an atmospheric quark creating a hadronic extensive air shower that contains a tau which subsequently decays creating a second extensive air shower. The number of these events strongly depends on the cross section and on the flux of ultra-high energy tau-neutrinos arriving at the Earth's atmosphere. We estimate the potential of optical detectors to observe Double-Bang events induced by tau-neutrinos with energies of about 1 EeV whose detection may confirm the maximal mixing observed in the atmospheric neutrinos also for ultra-high energy neutrinos, and give information on the neutrino flux and cross-section. For neutrino-nucleon Standard Model extrapolated cross-section and thick source model of flux (MPR), we estimate an event rate of 0.48/yr for an observatory with two fluorescence detectors with 90% efficiency in the neutrino energy range 0.5 < E_nu < 5 EeV.Comment: 17 pages, 6 eps figures, revtex 4, new calculation for the interaction probability end efficienc
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