11,459 research outputs found

    The Higgs mass in the MSSM infrared fixed point scenario

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    In the infrared fixed point (IFP) scenario of the minimal supersymmetric model (MSSM), the top-quark mass and other physical quantities of the low-energy theory are insensitive to the values of the parameters of the theory at some high energy scale. In this framework we evaluate the light CP-even Higgs mass, mhm_h, taking into account some important effects that had not been previously considered. In particular, the supersymmetric correction to the relation between the running and the physical top-quark masses lowers the value of tanβ\tan\beta, thereby implying a lower predicted value of mhm_h. Assuming a supersymmetric threshold of MS1M_S\leq 1 TeV and Mt=175M_t=175 GeV, we find an upper bound of mh97±2m_h\le 97\pm 2 GeV; the most plausible value of mhm_h lies somewhat below the upper bound. This places the Higgs boson in the IFP scenario well within the reach of the LEP-2 Higgs search.Comment: 18 pages, LaTeX, 5 ps figures, uses psfig.sty. Final version, some comments and a figure added, references correcte

    Gauge boson fusion as a probe of inverted hierarchies in supersymmetry

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    Supersymmetric scenarios with inverted mass hierarchy can be hard to observe at a hadron collider, particularly for the non-strongly interacting sector. We show how the production of stau-pairs via gauge boson fusion, along with hard jets in the high rapidity region, can be instrumental in uncovering the signatures of such scenarios. We demonstrate this both in a model-independent way and with reference to some specific, well-motivated models.Comment: RevTeX4, 4 pages, 2 figures. Final version to appear in Phys.Rev.D Changes in context, figures modified. References added. Conclusions unchange

    Assessing How Bankruptcy Prediction Models Are Evaluated

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    Since bankruptcy prediction became a popular research topic in the mid-1960s the model used for evaluating the research has remained largely unchanged.  A matched-pair sample design combined with a dichotomous classification test has been the standard.  This is quite useful from an academic perspective, but totally useless for any practical application.  When evaluating the paired-sample, the assumption is that random chance will correctly classify 50% of the companies as bankrupt or not, and any model that exceeds this is doing better than chance.  In the real world, of the 10,000 companies that trade on exchanges, only 600 will go bankrupt - this is a 6% failure rate, so any model should do better than 94% accuracy, not 50%.  Some companies might be eligible for bankruptcy, but choose not to file.  They might instead threaten to file, and negotiate concessions from creditors.  If this company was classified as bankrupt, would that be a correct or incorrect prediction?  The classic evaluation model would classify that as a miss, but is it really?  This paper addresses the shortcomings of bankruptcy prediction evaluation models and suggests that bankruptcy is better represented as a continuum, rather than a dichotomous situation

    Relativistic Quantum Thermodynamics of Ideal Gases in 2 Dimensions

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    In this work we study the behavior of relativistic ideal Bose and Fermi gases in two space dimensions. Making use of polylogarithm functions we derive a closed and unified expression for their densities. It is shown that both type of gases are essentially inequivalent, and only in the non-relativistic limit the spinless and equal mass Bose and Fermi gases are equivalent as known in the literature.Comment: 6 pages, 1 figur

    THE IDENTIFICATION OF THE DISCRETE-TIME HAMMERSTEIN MODEL

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    Space shuttle electromagnetic environment experiment. Phase A: Definition study

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    Methods for carrying out measurements of earth electromagnetic environment using the space shuttle as a measurement system platform are herein reported. The goal is to provide means for mapping intentional and nonintentional emitters on earth in the frequency range 0.4 to 40 GHz. A survey was made of known emitters using available data from national and international regulatory agencies, and from industry sources. The spatial distribution of sources, power levels, frequencies, degree of frequency re-use, etc., found in the survey, are here presented. A concept is developed for scanning the earth using a directive antenna whose beam is made to rotate at a fixed angle relative to the nadir; the illuminated area swept by the beam is of the form of cycloidal annulus over a sphere. During the beam's sojourn over a point, the receiver sweeps in frequency over ranges in the order of octave width using sweeping filter bandwidths sufficient to give stable readings
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