1,540 research outputs found

    The Markov Chain Interest Rate Scenario Generator Revisited

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    This paper furthers the development of the Markov chain interest rate generator. Though the basic technique remains essentially unchanged, there are still many significant changes to the model. For example: (i) the long (key) rates are now are generated by a mean reversionary process; (ii) the number of shapes is increased from seven to 11; (iii) the limitation of changing by only two shape codes per year is removed; and (iv) the random walk matrix that determines the shapes is revised to be more realistic. An algorithm is developed to determine the shape code of the original yield curve, thus eliminating an input and assuring consistency. Flexibility in the choice of the key rate is introduced. Implications of the choice of the key rate are discussed

    System size and beam energy dependence of azimuthal anisotropy from PHENIX

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    We present azimuthal anisotropy measurements in Au+Au and Cu+Cu collisions at sNN\sqrt{s_{NN}} = 62.4 and 200 GeV. Comparison between reaction plane and cumulant v2v_2 measurements in Au+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV show that non-flow contributions, originating mainly from jets, influence the extracted v2v_2 for pTp_T ≳\gtrsim 3.5 GeV/c. Number of constituent quark (NCQ) scaling of v2v_2, when studied as a function of transverse kinetic energy KETKE_T, is seen to hold for Au+Au collisions at sNN\sqrt{s_{NN}} = 62.4 and 200 GeV and for Cu+Cu collisions at sNN\sqrt{s_{NN}} = 200 GeV for KETKE_{T} ≲\lesssim 1 GeV/c. Differential hexadecupole flow v4v_4 seems to exhibit scaling with integral v2v_2 for centrality ≤\le 40% as has been observed for differential v2v_2.Comment: 4 pages, 3 figures, Proceedings of the QM2008 Conference, Jaipur, India February 4-10 200

    Measurement of charm and bottom production in p+p collisions at s\sqrt{s} = 200 GeV at RHIC-PHENIX

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    RHIC-PHENIX has observed a large suppression pattern and azimuthal anisotropy of non-photonic electron at mid-rapidity (∣η∣<0.35\mid\eta\mid<0.35) in Au+Au collisions at sNN=200\sqrt{s_{NN}} = 200 GeV. To understand these results and the interaction of heavy quarks in the hot and dense medium, experimental determination of production ratio of charm over bottom is one of the most important topics, since the behavior of bottom may differ from charm in the medium. We measured the ratio of charm over bottom and total cross section of bottom via partial reconstruction of D0^0→\toe+^+ K−^- νe\nu_e decay in p+p collisions at s=200\sqrt{s} = 200 GeV. Total cross sections of charm and bottom were also measured via di-electron continuum in p+p collisions at s=200\sqrt{s} = 200 GeV.Comment: 4pages, 4figures,coferenc

    Measurements of Cold Nuclear Matter Effects on J/psi in the PHENIX Experiment via Deuteron-Gold Collisions

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    A new calculation of R_{dAu} has been performed using the 2003 d+Au data and the higher-statistics 2005 p+p data. These nuclear modification factors are compared to calculations using nuclear-modified PDFs and a J/psi breakup cross section is extracted. These values are then used to project the cold nuclear matter effects in Au+Au collisions. Additionally, a more data-driven projection is performed.Comment: 4 pages, 6 figures, proceedings for Quark Matter 200

    Measurements of heavy quark production via single leptons at PHENIX

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    The measurement of single leptons from the semi-leptonic decay of heavy-flavor hadrons has long been a means for studying heavy-quark production. PHENIX has measured single muons in pp collisions at forward rapidity and single electrons in both pp and AuAu collisions at mid-rapidity at sqrt(s_NN)=200 GeV. The most recent PHENIX single lepton results are presented in the context of state-of-the-art pQCD calculations. An updated azimuthal anisotropy, v2(pT), measurement for heavy-flavor single electrons in AuAu collisions is also presented.Comment: 4 pages, 4 figures, presented at the 19th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions, "Quark Matter 2008", Jaipur, India, February 4-10, 200

    Real-life C-RAN deployment considerations

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    Experimental Evaluation of Empirical NB-IoT Propagation Modelling in a Deep-Indoor Scenario

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    Path-loss modelling in deep-indoor scenarios is a difficult task. On one hand, the theoretical formulae solely dependent on transmitter-receiver distance are too simple; on the other hand, discovering all significant factors affecting the loss of signal power in a given situation may often be infeasible. In this paper, we experimentally investigate the influence of deep-indoor features such as indoor depth, indoor distance and distance to the closest tunnel corridor and the effect on received power using NB-IoT. We describe a measurement campaign performed in a system of long underground tunnels, and we analyse linear regression models involving the engineered features. We show that the current empirical models for NB-IoT signal attenuation are inaccurate in a deep-indoor scenario. We observe that 1) indoor distance and penetration depth do not explain the signal attenuation well and increase the error of the prediction by 2-12 dB using existing models, and 2) a promising feature of average distance to the nearest corridor is identified.Comment: 6 pages, 6 figures, submitted to Globecom2020 conference, Selected Areas in Communications Symposium, Track on Internet of Things and Smart Connected Communitie

    A Search for a Sub-Earth Sized Companion to GJ 436 and a Novel Method to Calibrate Warm Spitzer IRAC Observations

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    We discovered evidence for a possible additional 0.75 R_Earth transiting planet in the NASA EPOXI observations of the known M dwarf exoplanetary system GJ 436. Based on an ephemeris determined from the EPOXI data, we predicted a transit event in an extant Spitzer Space Telescope 8 micron data set of this star. Our subsequent analysis of those Spitzer data confirmed the signal of the predicted depth and at the predicted time, but we found that the transit depth was dependent on the aperture used to perform the photometry. Based on these suggestive findings, we gathered new Warm Spitzer Observations of GJ 436 at 4.5 microns spanning a time of transit predicted from the EPOXI and Spitzer 8 micron candidate events. The 4.5 micron data permit us to rule out a transit at high confidence, and we conclude that the earlier candidate transit signals resulted from correlated noise in the EPOXI and Spitzer 8 micron observations. In the course of this investigation, we developed a novel method for correcting the intrapixel sensitivity variations of the 3.6 and 4.5 micron channels of the Infrared Array Camera (IRAC) instrument. We demonstrate the sensitivity of Warm Spitzer observations of M dwarfs to confirm sub-Earth sized planets. Our analysis will inform similar work that will be undertaken to use Warm Spitzer observations to confirm rocky planets discovered by the Kepler mission.Comment: 22 pages, 8 figures, accepted for publication in PAS
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