177 research outputs found

    Do Search for Dibaryonic De - Excitations in Relativistic Nuclear Reactions

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    Some odd characteristics are observed in the single particle distributions obtained from He+Li He + Li interactions at 4.5AGeV/c 4.5 AGeV/c momenta which are explained as the manifestation of a new mechanism of strangeness production via dibaryonic de-excitations. A signature of the formation of hadronic and baryonic clusters is also reported. The di-pionic signals of the dibaryonic orbital de-excitations are analyzed in the frame of the MIT - bag Model and a Monte Carlo simulation.The role played by the dibaryonic resonances in relativistic nuclear collisions could be a significant one. Key words: Relativistic nuclear interactions negative pions, negative kaons, di-pions , streamer chamber, dibaryons, MIT - bag model PACS codes: 25.75.+r,14.40.Aq,14.20.Pt,12.40.AsComment: 17 pages,LATEX, preprint ICTP -243 1993,figures available by reques

    The LUX Experiment

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    We present the status and prospects of the LUX experiment, which employs approximately 300 kg of two-phase xenon to search for WIMP dark matter interactions. The LUX detector was commissioned at the surface laboratory of the Sanford Underground Research Facility in Lead, SD, between December 2011 and February 2012 and the detector has been operating underground since January, 2013. These proceedings review the results of the commissioning run as well as the status of underground data-taking through the summer of 2013.Peer Reviewe

    Radiogenic and Muon-Induced Backgrounds in the LUX Dark Matter Detector

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    The Large Underground Xenon (LUX) dark matter experiment aims to detect rare low-energy interactions from Weakly Interacting Massive Particles (WIMPs). The radiogenic backgrounds in the LUX detector have been measured and compared with Monte Carlo simulation. Measurements of LUX high-energy data have provided direct constraints on all background sources contributing to the background model. The expected background rate from the background model for the 85.3 day WIMP search run is (2.6±0.2stat±0.4sys)×103(2.6\pm0.2_{\textrm{stat}}\pm0.4_{\textrm{sys}})\times10^{-3}~events~keVee1_{ee}^{-1}~kg1^{-1}~day1^{-1} in a 118~kg fiducial volume. The observed background rate is (3.6±0.4stat)×103(3.6\pm0.4_{\textrm{stat}})\times10^{-3}~events~keVee1_{ee}^{-1}~kg1^{-1}~day1^{-1}, consistent with model projections. The expectation for the radiogenic background in a subsequent one-year run is presented.Peer Reviewe

    Radon-related Backgrounds in the LUX Dark Matter Search

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    The LUX detector is currently in operation at the Davis Campus at the 4850’ level of the Sanford Underground Research Facility (SURF) in Lead, SD to directly search for WIMP dark matter. Knowing the type and rate of backgrounds is critical in a rare, low energy event search, and LUX was designed, constructed, and deployed to mitigate backgrounds, both internal and external. An important internal background are decays of radon and its daughters. These consist of alpha decays, which are easily tagged and are a tracer of certain backgrounds, and beta decays, some of which are not as readily tagged and present a background for the WIMP search. We report on studies of alpha decay and discuss implications for the WIMP search.Peer Reviewe

    NN final-state interaction in two-nucleon knockout from 16O^{16}O

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    The influence of the mutual interaction between the two outgoing nucleons (NN-FSI) in electro- and photoinduced two-nucleon knockout from 16O^{16}O has been investigated perturbatively. It turns out that the effect of NN-FSI depends on the kinematics and on the type of reaction considered. The effect is generally larger in pp- than in pn-knockout and in electron induced than in photoinduced reactions. In superparallel kinematics NN-FSI leads in the (e,epp)(e,e'pp) channel to a strong increase of the cross section, that is mainly due to a strong enhancement of the Δ\Delta-current contribution. In pn-emission, however, this effect is partially cancelled by a destructive interference with the seagull current. For photoreactions NN-FSI is considerably reduced in superparallel kinematics and can be practically negligible in specific kinematics.Comment: 16 pages, 9 figure

    A description of the ratio between electric and magnetic proton form factors by using space-like, time-like data and dispersion relations

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    We use the available information on the ratio between the electric and magnetic proton form factors coming from recently published space-like data and from the few available time-like data. We apply a dispersive procedure on these data to evaluate the behaviour of this ratio, as a complex function, for all values of q^2.Comment: 12 pages, 7 Encapsulated Postscript figures, uses epsfig, rotating, exscale, amsmath, cite, latexsym, graphics, color packages, added reference

    Application of several pretreatment technologies to a wastewater effluent of a petrochemical industry finally treated with reverse osmosis

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    [EN] This work studies the adequacy of different reverse osmosis (RO) pretreatments applied to different petrochemical wastewater effluents. Three effluents from a caprolactam factory were analysed: ion-exchange resin washing effluent (RWE), batch reactor washing effluent and factory outlet effluent. Coagulation–flocculation, microfiltration (MF) and ultrafiltration (UF) were tested as RO pretreatments. Various inorganic coagulants (Aluminium Chloride, Iron (III) Chloride, Aluminium Sulphate and polyaluminium chloride), commercial coagulants (Nophos and ACO) and commercial flocculants (polyacrylamide, CH-30 and active polyfloc) were tested at different dosages and stirring speeds. The highest removal of suspended solids (SS) and the lowest turbidity were obtained for the ion-exchange RWE. Two combinations of coagulants and flocculants were chosen as the most suitable conditions for the coagulation–flocculation process. The ion-exchange RWE was further treated with a combination of MF followed by UF. SS were completely removed and turbidity decreased to 0.136 NTU. The silt density index at 15 min was reduced to 6.41.The authors of this work wish to gratefully acknowledge the financial support from the Generalitat Valenciana through the programme “Ayudas para la realizacio´n de proyectos I+D para grupos de investigacio´n emergentes GV/2013”.Vincent Vela, MC.; Alvarez Blanco, S.; Lora García, J.; Carbonell Alcaina, C.; Sáez Muñoz, M. (2014). Application of several pretreatment technologies to a wastewater effluent of a petrochemical industry finally treated with reverse osmosis. Desalination and Water Treatment. 1-9. doi:10.1080/19443994.2014.939866S19Benito-Alcázar, C., Vincent-Vela, M. C., Gozálvez-Zafrilla, J. M., & Lora-García, J. (2010). Study of different pretreatments for reverse osmosis reclamation of a petrochemical secondary effluent. Journal of Hazardous Materials, 178(1-3), 883-889. doi:10.1016/j.jhazmat.2010.02.020Madaeni, S. S., & Eslamifard, M. R. (2010). Recycle unit wastewater treatment in petrochemical complex using reverse osmosis process. Journal of Hazardous Materials, 174(1-3), 404-409. doi:10.1016/j.jhazmat.2009.09.067Kim, H.-C., & Dempsey, B. A. (2008). Effects of wastewater effluent organic materials on fouling in ultrafiltration. Water Research, 42(13), 3379-3384. doi:10.1016/j.watres.2008.04.021Karabacakoğlu, B., Tezakıl, F., & Güvenç, A. (2014). Removal of hardness by electrodialysis using homogeneous and heterogeneous ion exchange membranes. Desalination and Water Treatment, 54(1), 8-14. doi:10.1080/19443994.2014.880159Gare, S. (2002). RO systems: the importance of pre-treatment. Filtration & Separation, 39(1), 22-27. doi:10.1016/s0015-1882(02)80047-7Garg, A., Mishra, I. M., & Chand, S. (2010). Effectiveness of coagulation and acid precipitation processes for the pre-treatment of diluted black liquor. Journal of Hazardous Materials, 180(1-3), 158-164. doi:10.1016/j.jhazmat.2010.04.008Verma, S., Prasad, B., & Mishra, I. M. (2010). Pretreatment of petrochemical wastewater by coagulation and flocculation and the sludge characteristics. Journal of Hazardous Materials, 178(1-3), 1055-1064. doi:10.1016/j.jhazmat.2010.02.047Garrote, J. (1995). Treatment of tannery effluents by a two step coagulation/flocculation process. Water Research, 29(11), 2605-2608. doi:10.1016/0043-1354(94)00312-uSanto, C. E., Vilar, V. J. P., Botelho, C. M. S., Bhatnagar, A., Kumar, E., & Boaventura, R. A. R. (2012). Optimization of coagulation–flocculation and flotation parameters for the treatment of a petroleum refinery effluent from a Portuguese plant. Chemical Engineering Journal, 183, 117-123. doi:10.1016/j.cej.2011.12.041Wang, J.-P., Chen, Y.-Z., Wang, Y., Yuan, S.-J., & Yu, H.-Q. (2011). Optimization of the coagulation-flocculation process for pulp mill wastewater treatment using a combination of uniform design and response surface methodology. Water Research, 45(17), 5633-5640. doi:10.1016/j.watres.2011.08.023Rossini, M., Garrido, J. G., & Galluzzo, M. (1999). Optimization of the coagulation–flocculation treatment: influence of rapid mix parameters. Water Research, 33(8), 1817-1826. doi:10.1016/s0043-1354(98)00367-4Guida, M., Mattei, M., Della Rocca, C., Melluso, G., & Meriç, S. (2007). Optimization of alum-coagulation/flocculation for COD and TSS removal from five municipal wastewater. Desalination, 211(1-3), 113-127. doi:10.1016/j.desal.2006.02.086HABERKAMP, J., RUHL, A., ERNST, M., & JEKEL, M. (2007). Impact of coagulation and adsorption on DOC fractions of secondary effluent and resulting fouling behaviour in ultrafiltration. Water Research, 41(17), 3794-3802. doi:10.1016/j.watres.2007.05.029Petrov, S., & Stoichev, P. (2002). Reagent ultrafiltration purification of water contaminated with reactive dyes. Filtration & Separation, 39(8), 35-34. doi:10.1016/s0015-1882(02)80229-4Shon, H. K., Vigneswaran, S., Ngo, H. H., & Ben Aim, R. (2005). Is semi-flocculation effective as pretreatment to ultrafiltration in wastewater treatment? Water Research, 39(1), 147-153. doi:10.1016/j.watres.2004.09.003Hatt, J. W., Germain, E., & Judd, S. J. (2011). Precoagulation-microfiltration for wastewater reuse. Water Research, 45(19), 6471-6478. doi:10.1016/j.watres.2011.09.039Dryden Aqua Ltd, Edinburgh, 2013. Available from: www.DrydenAqua.com (April 6, 2013).Sincero, A. P., & Sincero, G. A. (2002). Physical-Chemical Treatment of Water and Wastewater. doi:10.1201/978142003190

    Elliptic flow of charged particles in Pb-Pb collisions at 2.76 TeV

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    We report the first measurement of charged particle elliptic flow in Pb-Pb collisions at 2.76 TeV with the ALICE detector at the CERN Large Hadron Collider. The measurement is performed in the central pseudorapidity region (|η\eta|<0.8) and transverse momentum range 0.2< pTp_{\rm T}< 5.0 GeV/cc. The elliptic flow signal v2_2, measured using the 4-particle correlation method, averaged over transverse momentum and pseudorapidity is 0.087 ±\pm 0.002 (stat) ±\pm 0.004 (syst) in the 40-50% centrality class. The differential elliptic flow v2(pT)_2(p_{\rm T}) reaches a maximum of 0.2 near pTp_{\rm T} = 3 GeV/cc. Compared to RHIC Au-Au collisions at 200 GeV, the elliptic flow increases by about 30%. Some hydrodynamic model predictions which include viscous corrections are in agreement with the observed increase.Comment: 10 pages, 4 captioned figures, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/389
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