408 research outputs found

    Search for Narrow-Width ttbar Resonances in ppbar Collisions at center of mass energy = 1.8 TeV

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    We present a preliminary result on a search for narrow-width resonances that decay into ttbar pairs using 130 pb^{-1} of lepton plus jets data in ppbar collisions at center of mass energy = 1.8 TeV. No significant deviation from Standard Model prediction is observed. 95% C.L. upper limits on the production cross section of the narrow-width resonance times its branching fraction to ttbar are presented for different resonance masses, M_X. We also exclude the existence of a leptophobic topcolor particle, X, with M_X < 560 GeV/c^2 for a width \Gamma_X = 0.012 M_X.Comment: 3 pages, 1 figure; Submitted for proceedings of 5th International Conference on Quark Confinement and Hadron spectrum, held in Italy, from 11-14 Sep., 200

    Brane-Production and the Neutrino-Nucleon cross section at Ultra High Energies in Low Scale Gravity Models

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    The origin of the ultra high energy cosmic ray (UHECR) showers has remained as a mystery among particle physicists and astrophysicists. In low scale gravity models, where the neutrino-nucleon cross section rises to typical hadronic values at energies above 102010^{20} eV, the neutrino becomes a candidate for the primary that initiates these showers. We calculate the neutrino-nucleon cross section at ultra high energies by assuming that it is dominated by the production of p-branes. We show, using a generalized Randall-Sundrum model, that the neutrino-nucleon cross-section at neutrino energies of 101110^{11} GeV is of the order of 100 mb, which is required for explaining UHECR events. Similar result also follows in other models such as the Lykken-Randall model.Comment: 13 pages, 2 figures, significantly revised version, no change in conclusion

    Comparative study of nifepidine and isoxsuprine in suppression of preterm labour

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    Background: A prospective study was conducted to compare the efficacy of nifedipine against isoxsuprine in preventing preterm labour and also to evaluate maternal side effects and neonatal outcome.Methods: This was a randomized prospective comparative study done at MGM hospital and research center, Patna, Bihar between 15/03/2014 to 15/02/2016. 75 antenatal women with gestational age between 28 to 36 weeks were selected who fulfilled the inclusion criteria for the study, were given nifedipine and were monitored throughout the course of treatment.Results: Groups were compared with mean prolongation of delivery, side effects, neonatal outcome, parity, cervical effacements. Nifedipine was twice more effective than isoxsuprine hydrochloride as a uterine tocolytic agent while side effects were comparable with fewer side effects in nifedipine group. Neonatal outcome was better with nifedipine in comparison to isoxsuprine.Conclusions: There is a high incidence of preterm labour in India. The present study found that nifedipine has better tocolytic efficacy, less side effects and better tolerability as compared to isoxsuprine.

    Functionalized Carbon Nanotube and MnO2 Nanoflower Hybrid as an Electrode Material for Supercapacitor Application

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    Functionalized carbon nanotube (FCNT) and Manganese Oxide (MnO2) nanoflower hybrid material was synthesized using hydrothermal technique as a promising electrode material for supercapacitor applications. The morphological investigation revealed the formation of ‘nanoflower’ like structure of MnO2 connected with FCNT, thus paving an easy path for the conduction of electrons during the electrochemical mechanism. A significant improvement in capacitance properties was observed in the hybrid material, in which carbon nanotube acts as a conducting cylindrical path, while the major role of MnO2 was to store the charge, acting as an electrolyte reservoir leading to an overall improved electrochemical performance. The full cell electrochemical analysis of FCNT-MnO2 hybrid using 3 M potassium hydroxide (KOH) electrolyte indicated a specific capacitance of 359.53 F g−1, specific energy of 49.93 Wh kg−1 and maximum specific power of 898.84 W kg−1 at 5 mV s−1. The results show promise for the future of supercapacitor development based on hybrid electrode materials, where high specific energy can be achieved along with high specific power and long cycle life

    Cross Sections for Leptophobic Topcolor Z' decaying to top-antitop

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    We present numerical calculations of the production cross section of a heavy Z' resonance in hadron-hadron collisions with subsequent decay into top-antitop pairs. In particular, we consider the leptophobic topcolor Z' discussed under Model IV of hep-ph/9911288 which has predicted cross sections large enough to be experimentally accessible at the Fermilab Tevatron and the Large Hadron Collider at CERN. This article presents an updated calculation valid for the Tevatron and all proposed LHC collision energies. Cross sections are presented for various Z' widths, in p-pbar collisions at \sqrt{s}=2 TeV, and in p-p collisions at \sqrt{s}=7, 8, 10 and 14 TeV.Comment: 6 pages, 5 figures (Submitted to PRD); The European Physical Journal C, Volume 72, Issue

    Reference priors for high energy physics

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    Bayesian inferences in high energy physics often use uniform prior distributions for parameters about which little or no information is available before data are collected. The resulting posterior distributions are therefore sensitive to the choice of parametrization for the problem and may even be improper if this choice is not carefully considered. Here we describe an extensively tested methodology, known as reference analysis, which allows one to construct parametrization-invariant priors that embody the notion of minimal informativeness in a mathematically well-defined sense. We apply this methodology to general cross section measurements and show that it yields sensible results. A recent measurement of the single top quark cross section illustrates the relevant techniques in a realistic situation
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