3,892 research outputs found

    Threshold resummation for high-transverse-momentum Higgs production at the LHC

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    We study the resummation of large logarithmic QCD corrections for the process pp ->H+ X when the Higgs boson H is produced at high transverse momentum. The corrections arise near the threshold for partonic reaction and originate from soft gluon emission. We perform the all-order resummation at next-to-leading logarithmic accuracy and match the resummed result with the next-to-leading order perturbative predictions. The effect of resummation on the Higgs transverse momentum distribution at the LHC is discussed.Comment: 19 pages, 3 figure

    The Road Towards the ILC: Higgs, Top/QCD, Loops

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    The International Linear e+e- Collider (ILC) could go into operation in the second half of the upcoming decade. Experimental analyses and theory calculations for the physics at the ILC are currently performed. We review recent progress, as presented at the LCWS06 in Bangalore, India, in the fields of Higgs boson physics and top/QCD. Also the area of loop calculations, necessary to achieve the required theory precision, is included.Comment: 7 pages, 1 figure. Plenary talk given at the LCWS06 March 2006, Bangalore, India. Top part slightly enlarged, references adde

    Phase transition and anomalous electronic behavior in layered dichalcogenide CuS (covellite) probed by NQR

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    Nuclear quadrupole resonance (NQR) on copper nuclei has been applied for studies of the electronic properties of quasi-two-dimensional low-temperature superconductor CuS (covellite) in the temperature region between 1.47 and 290 K. Two NQR signals corresponding to two non-equivalent sites of copper in the structure, Cu(1) and Cu(2), has been found. The temperature dependences of copper quadrupole frequencies, line-widths and spin-lattice relaxation rates, which so far had never been investigated so precisely for this material, altogether demonstrate the structural phase transition near 55 K, which accompanies transformations of electronic spectrum not typical for simple metals. The analysis of NQR results and their comparison with literature data show that the valence of copper ions at both sites is intermediate in character between monovalent and divalent states with the dominant of the former. It has been found that there is a strong hybridization of Cu(1) and Cu(2) conduction bands at low temperatures, indicating that the charge delocalization between these ions takes place even in 2D regime. Based on our data, the occurrence of energy gap, charge fluctuations and charge-density waves, as well as the nature of phase transition in CuS are discussed. It is concluded that some physical properties of CuS are similar to those of high-temperature superconductors (HTSC) in normal state.Comment: to be publishe

    Ion metal synthesis in viscous organic matter

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    The viscosity of the irradiated target as new parameter was introduced in ion implantation physics of organic matter. It was experimentally shown that using this parameter one enables to monitor the process of ion synthesis of thin granular impurity films. As an example, the results of high-dose implantation of Co+ and Ag+ ions in viscous epoxy experimenting stages of cure (polymerization) process are presented. It was established by TEM that the mean size, size distributions, form and crystalline structure of the synthesized metal particles depend on both ion beam parameters and viscosity of the epoxy target. The mechanisms of homogeneous nucleation and diffusive growth of metal particles in the low-viscosity epoxy in contrast to heterogeneous nucleation in solid polymers are discussed. The threshold implantation dose that is necessary for the formation of stable metal phase nucleation in a viscous medium was calculated by using the diffusion equation with a continuous Gauss-like source for the implanting impurity. It is shown that the specificity of epoxy polymerization influences the growth and crystalline structure of metal particles at intermediate stages of the epoxy cure process. The preliminary investigation of magnetic, optical and electrical properties of synthesized films is described as well

    Educational laboratorial facility for researching the technology of plasma gasification of production and consumption wastes including medical wastes

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    © Published under licence by IOP Publishing Ltd. The article deals with the problems of waste management methods, which do not cope with the task of ecological utilization of solid waste. Based on the analysis of literature data, the following is presented: the morphological composition of solid waste, the block diagram of a laboratory waste gasification plant. And also a set of equipment characteristics for the modernization of a laboratory installation of plasma gasification

    Forward Jets and Energy Flow in Hadronic Collisions

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    We observe that at the Large Hadron Collider, using forward + central detectors, it becomes possible for the first time to carry out calorimetric measurements of the transverse energy flow due to "minijets" accompanying production of two jets separated by a large rapidity interval. We present parton-shower calculations of energy flow observables in a high-energy factorized Monte Carlo framework, designed to take into account QCD logarithmic corrections both in the large rapidity interval and in the hard transverse momentum. Considering events with a forward and a central jet, we examine the energy flow in the interjet region and in the region away from the jets. We discuss the role of these observables to analyze multiple parton collision effects.Comment: 9 pages, 5 figures. Version2: added results on azimuthal distributions and more discussion of energy flow definition using jet clusterin

    Giant QCD K-factors beyond NLO

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    Hadronic observables in Z+jet events can be subject to large NLO corrections at TeV scales, with K-factors that even reach values of order 50 in some cases. We develop a method, LoopSim, by which approximate NNLO predictions can be obtained for such observables, supplementing NLO Z+jet and NLO Z+2-jet results with a unitarity-based approximation for missing higher loop terms. We first test the method against known NNLO results for Drell-Yan lepton pt spectra. We then show our approximate NNLO results for the Z+jet observables. Finally we examine whether the LoopSim method can provide useful information even in cases without giant K-factors, with results for observables in dijet events that can be compared to early LHC data.Comment: 38 pages, 13 figures; v2 includes additional reference

    Sparticle mass spectra from SU(5) SUSY GUT models with bτb-\tau Yukawa coupling unification

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    Supersymmetric grand unified models based on the gauge group SU(5) often require in addition to gauge coupling unification, the unification of b-quark and τ\tau-lepton Yukawa couplings. We examine SU(5) SUSY GUT parameter space under the condition of bτb-\tau Yukawa coupling unification using 2-loop MSSM RGEs including full 1-loop threshold effects. The Yukawa-unified solutions break down into two classes. Solutions with low tan\beta ~3-11 are characterized by gluino mass ~1-4 TeV and squark mass ~1-5 TeV. Many of these solutions would be beyond LHC reach, although they contain a light Higgs scalar with mass <123 GeV and so may be excluded should the LHC Higgs hint persist. The second class of solutions occurs at large tan\beta ~35-60, and are a subset of tbτt-b-\tau unified solutions. Constraining only bτb-\tau unification to ~5% favors a rather light gluino with mass ~0.5-2 TeV, which should ultimately be accessible to LHC searches. While our bτb-\tau unified solutions can be consistent with a picture of neutralino-only cold dark matter, invoking additional moduli or Peccei-Quinn superfields can allow for all of our Yukawa-unified solutions to be consistent with the measured dark matter abundance.Comment: 19 pages, 5 figures, 1 table, PDFLate

    Signatures of the Light Down-Squark Scenario at the Upgraded Tevatron

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    In scenarios with relatively light down squarks, motivated, e.g., by SO(10) D terms, jets + missing ETE_T signals can be observed at the luminosity upgraded Tevatron even if the squarks are much heavier than the gluinos and the common gaugino mass (M1/2M_{{1/2}}) at MGM_G lies above the LEP allowed lower bound. In the conventional mSUGRA model with heavy squarks practically no signal is expected in this channel. The possiblity of distinguishing between various SUGRA motivated scenarios by exploiting the missing ETE_T and jet pTp_T distributions, opposite sign dileptons + jets + missing ETE_T events and clean trilepton signals have been discussed.Comment: 14 pages, 3 ps figure

    Non-invasive topical drug delivery to spinal cord with carboxyl-modified trifunctional copolymer of ethylene oxide and propylene oxide

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    © 2015 Elsevier B.V. In this study the effect of oxidative modification on micellar and drug delivery properties of copolymers of ethylene oxide (EO) and propylene oxide (PO) was investigated. Carboxylated trifunctional copolymers were synthesized in the reaction with chromium(VI) oxide. We found that carboxylation significantly improved the uniformity and stability of polymeric micelles by inhibiting the microphase transition. The cytotoxicity of copolymers was studied in relation to their aggregative state on two cell types (cancer line vs. primary fibroblasts). The accumulation of rhodamine 123 in neuroblastoma SH-SY5Y cells was dramatically increased in the presence of the oxidized block copolymer with the number of PO and EO units of 83.5 and 24.2, respectively. The copolymer was also tested as an enhancer for topical drug delivery to the spinal cord when applied subdurally. The oxidized copolymer facilitated the penetration of rhodamine 123 across spinal cord tissues and increased its intraspinal accumulation. These results show the potential of using oxidized EO/PO based polymers for non-invasive delivery of protective drugs after spinal cord injury
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