4,837 research outputs found

    Performance of the MIND detector at a Neutrino Factory using realistic muon reconstruction

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    A Neutrino Factory producing an intense beam composed of nu_e(nubar_e) and nubar_mu(nu_mu) from muon decays has been shown to have the greatest sensitivity to the two currently unmeasured neutrino mixing parameters, theta_13 and delta_CP . Using the `wrong-sign muon' signal to measure nu_e to nu_mu(nubar_e to nubar_mu) oscillations in a 50 ktonne Magnetised Iron Neutrino Detector (MIND) sensitivity to delta_CP could be maintained down to small values of theta_13. However, the detector efficiencies used in previous studies were calculated assuming perfect pattern recognition. In this paper, MIND is re-assessed taking into account, for the first time, a realistic pattern recognition for the muon candidate. Reoptimisation of the analysis utilises a combination of methods, including a multivariate analysis similar to the one used in MINOS, to maintain high efficiency while suppressing backgrounds, ensuring that the signal selection efficiency and the background levels are comparable or better than the ones in previous analyses

    Associated Charm Production in Neutrino-Nucleus Interactions

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    In this paper a search for associated charm production both in neutral and charged current ν\nu-nucleus interactions is presented. The improvement of automatic scanning systems in the {CHORUS} experiment allows an efficient search to be performed in emulsion for short-lived particles. Hence a search for rare processes, like the associated charm production, becomes possible through the observation of the double charm-decay topology with a very low background. About 130,000 ν\nu interactions located in the emulsion target have been analysed. Three events with two charm decays have been observed in the neutral-current sample with an estimated background of 0.18±\pm0.05. The relative rate of the associated charm cross-section in deep inelastic ν\nu interactions, σ(ccˉν)/σNCDIS=(3.622.42+2.95(stat)±0.54(syst))×103\sigma(c\bar{c}\nu)/\sigma_\mathrm{NC}^\mathrm{DIS}= (3.62^{+2.95}_{-2.42}({stat})\pm 0.54({syst}))\times 10^{-3} has been measured. One event with two charm decays has been observed in charged-current νμ\nu_\mu interactions with an estimated background of 0.18±\pm0.06 and the upper limit on associated charm production in charged-current interactions at 90% C.L. has been found to be σ(ccˉμ)/σCC<9.69×104\sigma (c\bar{c} \mu^-)/\sigma_\mathrm{CC} < 9.69 \times 10^{-4}.Comment: 10 pages, 4 figure

    Degradation and phase noise of InAlN/AlN/GaN heterojunction field effect transistors: Implications for hot electron/phonon effects

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    In15.7%Al84.3%N/AlN/GaN heterojunctionfield effect transistors have been electrically stressed under four different bias conditions: on-state-low-field stress, reverse-gate-bias stress, off-state-high-field stress, and on-state-high-field stress, in an effort to elaborate on hot electron/phonon and thermal effects. DC current and phase noise have been measured before and after the stress. The possible locations of the failures as well as their influence on the electrical properties have been identified. The reverse-gate-bias stress causes trap generation around the gate area near the surface which has indirect influence on the channel. The off-state-high-field stress and the on-state-high-field stress induce deterioration of the channel, reduce drain current and increase phase noise. The channel degradation is ascribed to the hot-electron and hot-phonon effects

    RAPD analysis of seized marijuana ( Cannabis sativa L.) in Turkey

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    Cannabis sativa L. is a multiple-use plant. However, its cultivation is strictly controlled due to its psychoactive nature and usage in producing drugs such as marijuana, and hashish. In this study, psychoactive type Cannabis samples, which were seized from 29 different locations of Turkey, were used. Interests were to identify the genetic relatedness of the seized samples and to partition molecular variance between and within populations. Randomly Amplified Polymorphic DNAs were employed for analysis based on single plant material and bulked samples of them. Data were analysed via cluster and principal coordinate analyses (PCoA). Analysis of molecular variance (AMOVA) was performed to obtain variations between and within populations. Cannabis accessions were basically separated into two main groups by PCoA and cluster analyses according to geographical regions. One of them was made up of Cannabis plants, which were seized from mostly western part of Turkey (group 1). The other one was made up of Cannabis plants that were seized from mostly eastern part of Turkey (group 2). It is found that 20.23% of the genetic variation is due to differences between accessions groups while 79.77% of the genetic variation is due to between accessions within accessions groups. Compared to group 1, group 2 showed more variation

    Physics with charm particles produced in neutrino interactions. A historical recollection

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    Results obtained in neutrino unteractions on charm particles are presented

    Leading order analysis of neutrino induced dimuon events in the CHORUS experiment

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    We present a leading order QCD analysis of a sample of neutrino induced charged-current events with two muons in the final state originating in the lead-scintillating fibre calorimeter of the CHORUS detector. The results are based on a sample of 8910 neutrino and 430 antineutrino induced opposite-sign dimuon events collected during the exposure of the detector to the CERN Wide Band Neutrino Beam between 1995 and 1998. % with Eμ1,Eμ2>5E_{\mu 1},E_{\mu 2} > 5 GeV and Q2>3Q^2 > 3 GeV2^2 collected %between 1995 and 1998. The analysis yields a value of the charm quark mass of \mc = (1.26\pm 0.16 \pm 0.09) \GeVcc and a value of the ratio of the strange to non-strange sea in the nucleon of κ=0.33±0.05±0.05\kappa = 0.33 \pm 0.05 \pm 0.05, improving the results obtained in similar analyses by previous experiments.Comment: Submitted to Nuclear Physics

    Testing Deconfinement at High Isospin Density

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    We study the transition from hadronic matter to a mixed phase of quarks and hadrons at high baryon and isospin densities reached in heavy ion collisions. We focus our attention on the role played by the nucleon symmetry energy at high density.In this respect the inclusion of a scalar isovector meson, the \delta-coupling, in the Hadron Lagrangian appears rather important. We study in detail the formation of a drop of quark matter in the mixed phase, and we discuss the effects on the quark drop nucleation probability of the finite size and finite time duration of the high density region. We find that, if the parameters of quark models are fixed so that the existence of quark stars is allowed, then the density at which a mixed phase starts forming drops dramatically in the range Z/A \sim 0.3--0.4. This opens the possibility to verify the Witten-Bodmer hypothesis on absolute stability of quark matter using ground-based experiments in which neutron-rich nuclei are employed. These experiments can also provide rather stringent constraints on the Equation of State (EoS) to be used for describing the pre-Supernova gravitational collapse. Consistent simulations of neutron rich heavy ion collisions are performed in order to show that even at relatively low energies, in the few AGeV range, the system can enter such unstable mixed phase. Some precursor observables are suggested, in particular a ``neutron trapping'' effect.Comment: 32 pages, 14 figures, elsart late

    Inter simple sequence repeats separate efficiently hemp from marijuana ( Cannabis sativa L.)

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    Cannabis sativa L. is a multiple-use plant that provides raw material for the production of seed oil, natural fiber for textiles, automotive and pulp industries. It has also been used in insulating boards, ropes, varnishes, animal feed, and as medicinal agents. Cannabis has potential to be used for phytoremediation: however, its cultivation is strictly controlled due to its psychoactive nature and usage in producing drugs such as marijuana, and hashish. In this study, psychoactive type Cannabis samples, which were seized from 23 different locations of Turkey, and nine hemp type Cannabis accessions, as well as an unknown accession were used. Our interest was to identify the genetic relatedness of the seized samples and to separate drug and hemp type plants. Inter Simple Sequence Repeats (ISSRs) were employed for analysis based on single plant material (SET1) and bulked samples of them (SET2). Data was analysed via cluster analysis and principal coordinate analysis (PCoA). PCoA analyses, by using SET1 and SET2, were able to efficiently discriminate the seized samples from the fiber type accessions. However, separation of the plants was not clear via unweighted pair-group method using arithmetic average (UPGMA) dendogram in SET1, while they were clearly separated in SET2. Hemp type accessions showed high levels of variation compared to drug type Cannabis both in SET1 and SET2

    Polarization phenomena in open charm photoproduction processes

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    We analyze polarization effects in associative photoproduction of pseudoscalar (Dˉ\bar{D}) charmed mesons in exclusive processes γ+NYc+Dˉ\gamma+ N\to Y_c +\bar{D}, Yc=Λc+Y_c=\Lambda_c^+, Σc\Sigma_c. Circularly polarized photons induce nonzero polarization of the YcY_c-hyperon with xx- and zz-components (in the reaction plane) and non vanishing asymmetries Ax{\cal A}_x and Az{\cal A}_z for polarized nucleon target. These polarization observables can be predicted in model-independent way for exclusive Dˉ\bar{D}-production processes in collinear kinematics. The T-even YcY_c-polarization and asymmetries for non-collinear kinematics can be calculated in framework of an effective Lagrangian approach. The depolarization coefficients DabD_{ab}, characterizing the dependence of the YcY_c-polarization on the nucleon polarization are also calculated.Comment: 36 pages 13 figure

    Comparison of large-angle production of charged pions with incident protons on cylindrical long and short targets

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    The HARP collaboration has presented measurements of the double-differential pi+/pi- production cross-section in the range of momentum 100 MeV/c <= p 800 MeV/c and angle 0.35 rad <= theta <= 2.15 rad with proton beams hitting thin nuclear targets. In many applications the extrapolation to long targets is necessary. In this paper the analysis of data taken with long (one interaction length) solid cylindrical targets made of carbon, tantalum and lead is presented. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN PS. The secondary pions were produced by beams of protons with momenta 5 GeV/c, 8 GeV/c and 12 GeV/c. The tracking and identification of the produced particles were performed using a small-radius cylindrical time projection chamber (TPC) placed inside a solenoidal magnet. Incident protons were identified by an elaborate system of beam detectors. Results are obtained for the double-differential yields per target nucleon d2 sigma / dp dtheta. The measurements are compared with predictions of the MARS and GEANT4 Monte Carlo simulations.Comment: 43 pages, 20 figure
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