383 research outputs found

    Matter wave solitons at finite temperatures

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    We consider the dynamics of a dark soliton in an elongated harmonically trapped Bose-Einstein condensate. A central question concerns the behavior at finite temperatures, where dissipation arises due to the presence of a thermal cloud. We study this problem using coupled Gross-Pitaevskii and NN-body simulations, which include the mean field coupling between the condensate and thermal cloud. We find that the soliton decays relatively quickly even at very low temperatures, with the decay rate increasing with rising temperature.Comment: 6 pages, 2 figures, submitted to the Proceedings of QFS '0

    Doping effect on the anomalous behavior of the Hall effect in electron-doped superconductor Nd2x_{2-x}Cex_xCuO4+δ_{4+\delta}

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    Transport properties of Nd2x_{2-x}Cex_xCuO4+δ_{4+\delta} single crystal films are investigated in magnetic fields BB up to 9T at TT=(0.4-4.2)K. An analysis of normal state (at B>Bc2B>B_{c2}) Hall coefficient RHR_Hn^n dependence on Ce doping takes us to a conclusion about the existence both of electron-like and hole-like contributions to transport in nominally electron-doped system. In accordance with RHR_Hn^n(x) analysis an anomalous sign reversal of Hall effect in mixed state at B<Bc2B<B_{c2} may be ascribed to a flux-flow regime for two types of carriers with opposite charges.Comment: 14 pages, 5 figure

    The controlled teleportation of an arbitrary two-atom entangled state in driven cavity QED

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    In this paper, we propose a scheme for the controlled teleportation of an arbitrary two-atom entangled state ϕ>12=agg>12+bge>12+ceg>12+dee>12|\phi>_{12}=a|gg>_{12}+b|ge>_{12}+c|eg>_{12}+d|ee>_{12} in driven cavity QED. An arbitrary two-atom entangled state can be teleported perfectly with the help of the cooperation of the third side by constructing a three-atom GHZ entangled state as the controlled channel. This scheme does not involve apparent (or direct) Bell-state measurement and is insensitive to the cavity decay and the thermal field. The probability of the success in our scheme is 1.0.Comment: 10 page

    Charged Higgs Boson Production in Bottom-Gluon Fusion

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    We compute the complete next-to-leading order SUSY-QCD corrections for the associated production of a charged Higgs boson with a top quark via bottom-gluon fusion. We investigate the applicability of the bottom parton description in detail. The higher order corrections can be split into real and virtual corrections for a general two Higgs doublet model and into additional massive supersymmetric loop contributions. We find that the perturbative behavior is well under control. The supersymmetric contributions consist of the universal bottom Yukawa coupling corrections and non-factorizable diagrams. Over most of the relevant supersymmetric parameter space the Yukawa coupling corrections are sizeable, while the remaining supersymmetric loop contributions are negligible.Comment: 18 pages, v2: some discussions added, v3: published versio

    Supersymmetric Electroweak Corrections to Charged Higgs Boson Production in Association with a Top Quark at Hadron Colliders

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    We calculate the O(αewmt(b)2/mW2)O(\alpha_{ew}m_{t(b)}^{2}/m_{W}^{2}) and O(αewmt(b)4/mW4)O(\alpha_{ew} m_{t(b)}^4/m_W^4) supersymmetric electroweak corrections to the cross section for the charged Higgs boson production in association with a top quark at the Tevatron and the LHC. These corrections arise from the quantum effects which are induced by potentially large Yukawa couplings from the Higgs sector and the chargino-top(bottom)-sbottom(stop) couplings, neutralino-top(bottom)-stop(sbottom) couplings and charged Higgs-stop-sbottom couplings. They can decrease or increase the cross section depending on tanβ\tan\beta but are not very sensitive to the mass of the charged Higgs boson for high tanβ\tan\beta. At low tanβ(=2)\tan\beta(=2) the corrections decrease the total cross sections significantly, which exceed -12% for mH±m_{H^{\pm}} below 300GeV300GeV at both the Tevatron and the LHC, but for mH±>300GeVm_{H^{\pm}}>300GeV the corrections can become very small at the LHC. For high tanβ(=10,30)\tan\beta(=10,30) these corrections can decrease or increase the total cross sections, and the magnitude of the corrections are at most a few percent at both the Tevatron and the LHC.Comment: 28 pages including 4 eps figure

    Development of a 96-well plate sample preparation method for integratedN- andO-glycomics using porous graphitized carbon liquid chromatography-mass spectrometry

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    Changes in glycosylation signatures of cells have been associated with pathological processes in cancer as well as infectious and autoimmune diseases. The current protocols for comprehensive analysis ofN-glycomics andO-glycomics derived from cells and tissues often require a large amount of biological material. They also only allow the processing of very limited numbers of samples at a time. Here we established a workflow for sequential release ofN-glycans andO-glycans based on PVDF membrane immobilization in 96-well format from 5 x 10(5)cells. Released glycans are reduced, desalted, purified, and reconstituted, all in 96-well format plates, without additional staining or derivatization. Glycans are then analyzed with porous graphitized carbon nano-liquid chromatography coupled to tandem mass spectrometry using negative-mode electrospray ionization, enabling the chromatographic resolution and structural elucidation of glycan species including many compositional isomers. The approach was demonstrated using glycoprotein standards and further applied to analyze the glycosylation of the murine mammary gland NMuMG cell line. The developed protocol allows the analysis ofN- andO-glycans from relatively large numbers of samples in a less time consuming way with high repeatability. Inter- and intraday repeatability of the fetuinN-glycan analysis showed two median intraday coefficients of variations (CVs) of 7.6% and 8.0%, and a median interday CV of 9.8%. Median CVs of 7.9% and 8.7% for the main peaks ofN- andO-glycans released from the NMuMG cell line indicate a very good repeatability. The method is applicable to purified glycoproteins as well as to biofluids and cell- or tissue-based samples.Cancer Signaling networks and Molecular Therapeutic

    Higgs-Boson Production Induced by Bottom Quarks

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    Bottom quark-induced processes are responsible for a large fraction of the LHC discovery potential, in particular for supersymmetric Higgs bosons. Recently, the discrepancy between exclusive and inclusive Higgs boson production rates has been linked to the choice of an appropriate bottom factorization scale. We investigate the process kinematics at hadron colliders and show that it leads to a considerable decrease in the bottom factorization scale. This effect is the missing piece needed to understand the corresponding higher order results. Our results hold generally for charged and for neutral Higgs boson production at the LHC as well as at the Tevatron. The situation is different for single top quark production, where we find no sizeable suppression of the factorization scale. Turning the argument around, we can specify how large the collinear logarithms are, which can be resummed using the bottom parton picture.Comment: 18 page

    Prospects for heavy supersymmetric charged Higgs boson searches at hadron colliders

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    We investigate the production of a heavy charged Higgs boson at hadron colliders within the context of the MSSM. A detailed study is performed for all important production modes and basic background processes for the t\bar{t}b\bar{b} signature. In our analysis we include effects of initial and final state showering, hadronization, and principal detector effects. For the signal production rate we include the leading SUSY quantum effects at high \tan\beta>~ mt/mb. Based on the obtained efficiencies for the signal and background we estimate the discovery and exclusion mass limits of the charged Higgs boson at high values of \tan\beta. At the upgraded Tevatron the discovery of a heavy charged Higgs boson (MH^+ >~ 200 GeV) is impossible for the tree-level cross-section values. However, if QCD and SUSY effects happen to reinforce mutually, there are indeed regions of the MSSM parameter space which could provide 3\sigma evidence and, at best, 5\sigma charged Higgs boson discovery at the Tevatron for masses M_H^+<~ 300 GeV and M_H^+<~ 250 GeV, respectively, even assuming squark and gluino masses in the (500-1000) GeV range. On the other hand, at the LHC one can discover a H^+ as heavy as 1 TeV at the canonical confidence level of 5\sigma; or else exclude its existence at 95% C.L. up to masses ~ 1.5 TeV. Again the presence of SUSY quantum effects can be very important here as they may shift the LHC limits by a few hundred GeV.Comment: Latex2e, 44 pages, 15 figures, 6 tables, uses JHEP3.sty, axodraw.sty. Comments added. Discussion on QCD factors clarified. Added discussion on uncertainties. Change of presentation of Tables 4 and 5 and Fig.6. Results and conclusions unchanged. Version accepted in JHE

    Longitudinal double-spin asymmetry and cross section for inclusive neutral pion production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV

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    We report a measurement of the longitudinal double-spin asymmetry A_LL and the differential cross section for inclusive Pi0 production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV. The cross section was measured over a transverse momentum range of 1 < p_T < 17 GeV/c and found to be in good agreement with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry was measured in the range of 3.7 < p_T < 11 GeV/c and excludes a maximal positive gluon polarization in the proton. The mean transverse momentum fraction of Pi0's in their parent jets was found to be around 0.7 for electromagnetically triggered events.Comment: 6 pages, 3 figures, submitted to Phys. Rev. D (RC

    High pTp_{T} non-photonic electron production in pp+pp collisions at s\sqrt{s} = 200 GeV

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    We present the measurement of non-photonic electron production at high transverse momentum (pT>p_T > 2.5 GeV/cc) in pp + pp collisions at s\sqrt{s} = 200 GeV using data recorded during 2005 and 2008 by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The measured cross-sections from the two runs are consistent with each other despite a large difference in photonic background levels due to different detector configurations. We compare the measured non-photonic electron cross-sections with previously published RHIC data and pQCD calculations. Using the relative contributions of B and D mesons to non-photonic electrons, we determine the integrated cross sections of electrons (e++e2\frac{e^++e^-}{2}) at 3 GeV/c<pT< c < p_T <~10 GeV/cc from bottom and charm meson decays to be dσ(Be)+(BDe)dyeye=0{d\sigma_{(B\to e)+(B\to D \to e)} \over dy_e}|_{y_e=0} = 4.0±0.5\pm0.5({\rm stat.})±1.1\pm1.1({\rm syst.}) nb and dσDedyeye=0{d\sigma_{D\to e} \over dy_e}|_{y_e=0} = 6.2±0.7\pm0.7({\rm stat.})±1.5\pm1.5({\rm syst.}) nb, respectively.Comment: 17 pages, 17 figure
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