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Sample records for zeus micro vertex

  1. The design and performance of the ZEUS micro vertex detector

    International Nuclear Information System (INIS)

    Polini, A.; Brock, I.; Goers, S.

    2007-08-01

    In order to extend the tracking acceptance, to improve the primary and secondary vertex reconstruction and thus enhancing the tagging capabilities for short lived particles, the ZEUS experiment at the HERA Collider at DESY installed a silicon strip vertex detector. The barrel part of the detector is a 63 cm long cylinder with silicon sensors arranged around an elliptical beampipe. The forward part consists of four circular shaped disks. In total just over 200k channels are read out using 2.9 m 2 of silicon. In this report a detailed overview of the design and construction of the detector is given and the performance of the completed system is reviewed. (orig.)

  2. The design and performance of the ZEUS micro vertex detector

    Energy Technology Data Exchange (ETDEWEB)

    Polini, A. [Bologna Univ. (Italy)]|[INFN Bologna (Italy); Brock, I.; Goers, S. [Bonn Univ. (DE). Physikalisches Institut] (and others)

    2007-08-15

    In order to extend the tracking acceptance, to improve the primary and secondary vertex reconstruction and thus enhancing the tagging capabilities for short lived particles, the ZEUS experiment at the HERA Collider at DESY installed a silicon strip vertex detector. The barrel part of the detector is a 63 cm long cylinder with silicon sensors arranged around an elliptical beampipe. The forward part consists of four circular shaped disks. In total just over 200k channels are read out using 2.9 m{sup 2} of silicon. In this report a detailed overview of the design and construction of the detector is given and the performance of the completed system is reviewed. (orig.)

  3. Design and Tests of the Silicon Sensors for the ZEUS Micro Vertex Detector

    OpenAIRE

    Dannheim, D.; Koetz, U.; Coldewey, C.; Fretwurst, E.; Garfagnini, A.; Klanner, R.; Martens, J.; Koffeman, E.; Tiecke, H.; Carlin, R.

    2002-01-01

    To fully exploit the HERA-II upgrade,the ZEUS experiment has installed a Micro Vertex Detector (MVD) using n-type, single-sided, silicon micro-strip sensors with capacitive charge division. The sensors have a readout pitch of 120 micrometers, with five intermediate strips (20 micrometer strip pitch). The designs of the silicon sensors and of the test structures used to verify the technological parameters, are presented. Results on the electrical measurements are discussed. A total of 1123 sen...

  4. Design and tests of the silicon sensors for the ZEUS micro vertex detector

    International Nuclear Information System (INIS)

    Dannheim, D.; Koetz, U.; Coldewey, C.; Fretwurst, E.; Garfagnini, A.; Klanner, R.; Martens, J.; Koffeman, E.; Tiecke, H.; Carlin, R.

    2003-01-01

    To fully exploit the HERA-II upgrade, the ZEUS experiment has installed a Micro Vertex Detector (MVD) using n-type, single-sided, silicon μ-strip sensors with capacitive charge division. The sensors have a readout pitch of 120 μm, with five intermediate strips (20 μm strip pitch). The designs of the silicon sensors and of the test structures used to verify the technological parameters, are presented. Results on the electrical measurements are discussed. A total of 1123 sensors with three different geometries have been produced by Hamamatsu Photonics K.K. Irradiation tests with reactor neutrons and 60 Co photons have been performed for a small sample of sensors. The results on neutron irradiation (with a fluence of 1x10 13 1 MeV equivalent neutrons/cm 2 ) are well described by empirical formulae for bulk damage. The 60 Co photons (with doses up to 2.9 kGy) show the presence of generation currents in the SiO 2 -Si interface, a large shift of the flatband voltage and a decrease of the hole mobility

  5. Search for decaying neutralions at HERA and clustering optimisation for the ZEUS micro vertex detector

    International Nuclear Information System (INIS)

    Blohm, Christian

    2010-03-01

    A search for gravitinos produced in supersymmetric events in electron proton collision has been performed with data recorded with the ZEUS detector at HERA in the years 2003 to 2007. In R-parity violating supersymmetric models a neutralino can be produced by t-channel exchange of a selectron between the incoming electron and a quark of the proton. In the Gauge Mediated Supersymmetry Breaking model (GMSB), where the gravitino is the lightest supersymmetric particle, the neutralino in large regions of the parameter space dominantly decays into a gravitino and a photon, leading to events with an isolated high energetic photon and large missing transverse momentum. To separate signal and background, a multi-variate discriminant method was used. No evidence for supersymmetry was found, and limits were derived for the R-parity violating coupling strength and the messes of the selectron and the lightest neutralino. Moreover, the cluster position reconstruction system of the ZEUS experiment was improved by modifying and implementing an algorithm which uses estimated track angle and impact position from the pattern recognition phase of the tracking system to yield a better position resolution. (orig.)

  6. The ZEUS vertex detector: Design and prototype

    International Nuclear Information System (INIS)

    Alvisi, C.; Anzivino, G.; Arzarello, F.; Barbagli, G.; Bari, G.; Basile, M.; Bellagamba, L.; Boscherini, D.; Bruni, G.; Bruni, P.; Camerini, U.; Cara Romeo, G.; Castellini, G.; Chiarini, M.; Cifarelli, L.; Cindolo, F.; Ciralli, F.; Contin, A.; Costa, M.; D'Auria, S.; Del Papa, C.; De Pasquale, S.; Fiori, F.; Forte, A.; Frasconi, F.; Giusti, P.; Iacobucci, G.; Laurenti, G.; Lisowski, B.; Maccarrone, G.; Margotti, A.; Massam, T.; Nania, R.; O'Shea, V.; Palmonari, F.; Pelfer, P.; Pilastrini, R.; Qian, S.; Sartorelli, G.; Schioppa, M.; Susinno, G.; Timellini, R.; Zichichi, A.; Bologna Univ.; Cosenza Univ.; Florence Univ.; Istituto Nazionale di Fisica Nucleare, Bologna; Istituto Nazionale di Fisica Nucleare, Florence; Istituto Nazionale di Fisica Nucleare, Frascati; Consiglio Nazionale delle Ricerche, Florence

    1991-01-01

    A gas vertex detector, operated with dimethylether (DME) at atmospheric pressure, is presently being built for the ZEUS experiment at HERA. Its main design features, together with the performances of a prototype measured at various operating voltages, particle rates and geometrical conditions on a CERN Proton Synchrotron test beam, are presented. A spatial resolution down to 35 μm and an average wire efficiency of 96% have been achieved, for a 3 mm gas gap relative to each sense wire. (orig.)

  7. Status of the CBM micro vertex detector

    Energy Technology Data Exchange (ETDEWEB)

    Koziel, Michal [Goethe-Universitaet Frankfurt (Germany); Collaboration: CBM-MVD-Collaboration

    2015-07-01

    The fixed-target experiment CBM at FAIR will explore the phase diagram of strongly interacting matter in the regime of highest net baryon densities with numerous probes, among them open charm. For the reconstruction of open charm hadrons with the CBM experiment a Micro Vertex Detector (MVD) with an excellent spatial resolution of the secondary decay vertex is required. Hence, a material budget of a few 0.1% X0 is mandatory for the individual detector stations positioned downstream in close vicinity to the target. To reduce multiple scattering, the MVD operates in vacuum, which poses challenging requirements on both, the power dissipation of the sensors and the integration concept. Here one should mention the selection of high-performance materials providing the mechanical support and cooling for the 0.05 mm thin sensors, establishing the sensor quality assessment procedures as well as defining the sensor integration. In addition, a substantial progress with respect to sensor development will be reported, mainly to the studies on their radiation hardness. Also, the 2nd generation of the sensor control and read-out based on TRBv3 standard has been commissioned. In this contribution we highlight several activities that have been successfully accomplished, which enable us to define the start version of the CBM MVD.

  8. Measurement of beauty and charm photoproduction using inclusive secondary vertexing with the ZEUS detector at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Schoenberg, Verena Ellen

    2010-04-15

    Photoproduction of heavy quarks in events with two jets has been measured with the ZEUS detector at HERA using data recorded in the years 2006-2007 corresponding to an integrated luminosity of 128 pb{sup -1}. The beauty and charm content was extracted using the decay-length significance of the b and c hadrons and the invariant mass of the decay vertices. Differential cross sections as a function of P{sup Jet}{sub T} and {eta}{sup Jet} were compared with the PYTHIA leading order plus parton shower Monte Carlo and QCD predictions calculated at next-to-leading order. In order to study the theoretical description of higher-order effects correlations between the two highest energy jets were also investigated. (orig.)

  9. Measurement of beauty and charm photoproduction using inclusive secondary vertexing with the ZEUS detector at HERA

    International Nuclear Information System (INIS)

    Schoenberg, Verena Ellen

    2010-04-01

    Photoproduction of heavy quarks in events with two jets has been measured with the ZEUS detector at HERA using data recorded in the years 2006-2007 corresponding to an integrated luminosity of 128 pb -1 . The beauty and charm content was extracted using the decay-length significance of the b and c hadrons and the invariant mass of the decay vertices. Differential cross sections as a function of P Jet T and η Jet were compared with the PYTHIA leading order plus parton shower Monte Carlo and QCD predictions calculated at next-to-leading order. In order to study the theoretical description of higher-order effects correlations between the two highest energy jets were also investigated. (orig.)

  10. Technical Design Report for the: PANDA Micro Vertex Detector

    CERN Document Server

    Erni, W; Krusche, B; Steinacher, M; Heng, Y; Liu, Z; Liu, H; Shen, X; Wang, Q; Xu, H; Albrecht, M; Becker, J; Eickel, K; Feldbauer, F; Fink, M; Friedel, P; Heinsius, F H; Held, T; Koch, H; Kopf, B; Leyhe, M; Motzko, C; Pelizäus, M; Pychy, J; Roth, B; Schröder, T; Schulze, J; Steinke, M; Trifterer, T; Wiedner, U; Zhong, J; Beck, R; Becker, M; Bianco, S; Brinkmann, K -Th; Hammann, C; Hinterberger, F; Jäkel, R; Kaiser, D; Kliemt, R; Koop, K; Schmidt, C; Schnell, R; Thoma, U; Vlasov, P; Wendel, C; Winnebeck, A; Würschig, Th; Zaunick, H -G; Bianconi, A; Bragadireanu, M; Caprini, M; Ciubancan, M; Pantea, D; Tarta, P -D; De Napoli, M; Giacoppo, F; Rapisarda, E; Sfienti, C; Fiutowski, T; Idzik, N; Mindur, B; Przyborowski, D; Swientek, K; Bialkowski, E; Budzanowski, A; Czech, B; Kliczewski, S; Kozela, A; Kulessa, P; Lebiedowicz, P; Malgorzata, K; Pysz, K; Schäfer, W; Siudak, R; Szczurek, A; Brandys, P; Czyzewski, T; Czyzycki, W; Domagala, M; Hawryluk, M; Filo, G; Kwiatkowski, D; Lisowski, E; Lisowski, F; Bardan, W; Gil, D; Kamys, B; Kistryn, St; Korcyl, K; Krzemieñ, W; Magiera, A; Moskal, P; Rudy, Z; Salabura, P; Smyrski, J; Wroñska, A; Al-Turany, M; Arora, R; Augustin, I; Deppe, H; Dutta, D; Flemming, H; Götzen, K; Hohler, G; Karabowicz, R; Lehmann, D; Lewandowski, B; Lühning, J; Maas, F; Orth, H; Peters, K; Saito, T; Schepers, G; Schmidt, C J; Schmitt, L; Schwarz, C; Schwiening, J; Voss, B; Wieczorek, P; Wilms, A; Abazov, V M; Alexeev, G D; Arefiev, V A; Astakhov, V I; Barabanov, M Yu; Batyunya, B V; Davydov, Yu I; Dodokhov, V Kh; Efremov, A A; Fedunov, A G; Feshchenko, A A; Galoyan, A S; Grigoryan, S; Karmokov, A; Koshurnikov, E K; Lobanov, V I; Lobanov, Yu Yu; Makarov, A F; Malinina, L V; Malyshev, V L; Mustafaev, G A; Olshevski, A G; Pasyuk, M A; Perevalova, E A; Piskun, A A; Pocheptsov, T A; Pontecorvo, G; Rodionov, V K; Rogov, Yu N; Salmin, R A; Samartsev, A G; Sapozhnikov, M G; Shabratova, G S; Skachkova, A N; Skachkov, N B; Strokovsky, E A; Suleimanov, M K; Teshev, R Sh; Tokmenin, V V; Uzhinsky, V V; Vodopyanov, A S; Zaporozhets, S A; Zhuravlev, N I; Zorin, A G; Branford, D; Glazier, D; Watts, D; Woods, P; Britting, A; Eyrich, W; Lehmann, A; Uhlig, F; Dobbs, S; Metreveli, Z; Seth, K; Tann, B; Tomaradze, A; Bettoni, D; Carassiti, V; Dalpiaz, P; Drago, A; Fioravanti, E; Garzia, I; Negrini, M; Savriè, M; Stancari, G; Dulach, B; Gianotti, P; Guaraldo, C; Lucherini, V; Pace, E; Bersani, A; Macri, M; Marinelli, M; Parodi, R F; Dormenev, V; Drexler, P; Düren, M; Eisner, T; Foehl, K; Hayrapetyan, A; Koch, P; Krïoch, B; Kühn, W; Lange, S; Liang, Y; Liu, M; Merle, O; Metag, V; Moritz, M; Nanova, M; Novotny, R; Spruck, B; Stenzel, H; Strackbein, C; Thiel, M; Wang, Q; Clarkson, T; Euan, C; Hill, G; Hoek, M; Ireland, D; Kaiser, R; Keri, T; Lehmann, I; Livingston, K; Lumsden, P; MacGregor, D; McKinnon, B; Montgomery, R; Murray, M; Protopopescu, D; Rosner, G; Seitz, B; Yang, G; Babai, M; Biegun, A K; Glazenborg-Kluttig, A; Guliyev, E; Jothi, V S; Kavatsyuk, M; Lemmens, P; Löhner, H; Messchendorp, J; Poelman, T; Smit, H; van der Weele, J C; Sohlbach, H; Büscher, M; Dosdall, R; Dzhygadlo, R; Esch, S; Gillitzer, A; Goldenbaum, F; Grunwald, D; Jha, V; Kemmerling, G; Kleines, H; Lehrach, A; Maier, R; Mertens, M; Ohm, H; Pohl, D L; Prasuhn, D; Randriamalala, T; Ritman, J; Roeder, M; Sterzenbach, G; Stockmanns, T; Wintz, P; Wüstner, P; Xu, H; Kisiel, J; Li, S; Li, Z; Sun, Z; Xu, H; Fissum, K; Hansen, K; Isaksson, L; Lundin, M; Schröder, B; Achenbach, P; Denig, A; Distler, M; Fritsch, M; Kangh, D; Karavdina, A; Lauth, W; Michel, M; Espi, M C Mora; Pochodzalla, J; Sanchez, S; Sanchez-Lorente, A; Sfienti, C; Weber, T; Dormenev, V I; Fedorov, A A; Korzhik, M V; Missevitch, O V; Boukharov, A; Malyshev, O; Marishev, I; Semenov, A; Varma, R; Höppner, C; Ketzer, B; Konorov, I; Mann, A; Neubert, S; Paul, S; Vandenbroucke, M; Zhang, Q; Khoukaz, A; Rausmann, T; Täschner, A; Wessels, J; Baldin, E; Kotov, K; Peleganchuk, S; Tikhonov, Yu; Hennino, T; Imre, M; Kunne, R; Galliard, C Le; Normand, J P Le; Marchand, D; Maroni, A; Ong, S; Pouthas, J; Ramstein, B; Rosier, P; Sudol, M; Theneau, C; Tomasi-Gustafsson, E; Van de Wiele, J; Zerguerras, T; Boca, G; Braghieri, A; Costanza, S; Fontana, A; Genova, P; Lavezzi, L; Montagna, P; Rotondi, A; Buda, V; Abramov, V V; Davidenko, A M; Derevschikov, A A; Goncharenko, Y M; Grishin, V N; Kachanov, V A; Konstantinov, D A; Kormilitsin, V A; Matulenko, Y A; Melnik, Y M; Meschanin, A P; Minaev, N G; Mochalov, V V; Morozov, D A; Nogach, L V; Nurushev, S B; Ryazantsev, A V; Semenov, P A; Soloviev, L F; Uzunian, A V; Vasiliev, A N; Yakutin, A E; Belostotski, S; Gavrilov, G; Itzotov, A; Kisselev, A; Kravchenko, P; Manaenkov, S; Miklukho, O; Naryshkin, Y; Veretennikov, D; Vikhrov, V; Zhadanov, A; Bäck, T; Cederwall, B; Bargholtz, C; Gerén, L; Tegnér, P E; Thørngren, P; von Würtemberg, K M; Fava, L; Alberto, D; Amoroso, A; Bussa, M P; Busso, L; De Mori, F; Destefanis, M; Ferrero, L; Greco, M; Kugathasan, T; Maggiora, M; Marcello, S; Sosio, S; Spataro, S; Calvo, D; Coli, S; De Remigis, P; Filippi, A; Giraudo, G; Lusso, S; Mazza, G; Mignone, M; Rivetti, A; Wheadon, R; Zotti, L; Morra, O; Iazzi, F; Lavagno, A; Quarati, P; Szymanska, K; Birsa, R; Bradamante, F; Bressan, A; Martin, A; Clement, H; Galnander, B; Calén, H; Fransson, K; Johansson, T; Kupsc, A; Marciniewski, P; Thomé, E; Wolke, M; Zlomanczuk, J; Díaz, J; Ortiz, A; Buda, P; Dmowski, K; Korzeniewski, R; Przemyslaw, D; Slowinski, B; Borsuk, S; Chlopik, A; Guzik, Z; Kopec, J; Kozlowski, T; Melnychuk, D; Plominski, M; Szewinski, J; Traczyk, K; Zwieglinski, B; Bühler, P; Gruber, A; Kienle, P; Marton, J; Widmann, E; Zmeskal, J

    2012-01-01

    This document illustrates the technical layout and the expected performance of the Micro Vertex Detector (MVD) of the PANDA experiment. The MVD will detect charged particles as close as possible to the interaction zone. Design criteria and the optimisation process as well as the technical solutions chosen are discussed and the results of this process are subjected to extensive Monte Carlo physics studies. The route towards realisation of the detector is outlined.

  11. Optimising of design parameters of the TESLA vertex detector and search for events with isolated leptons and large missing transverse momentum with the ZEUS-experiment (HERA II)

    Energy Technology Data Exchange (ETDEWEB)

    Adler, V.

    2006-06-15

    In this thesis, a search for events with isolated leptons and large missing transverse momentum at HERA is presented. Data with an integrated luminosity of 40.76 pb{sup -1} of e{sup +}p-collisions collected with the ZEUS detector at a CMS energy of 318 GeV during the HERA II running period in the years 2003 and 2004 were used. Some extensions of the SM contain FCNC processes at tree level, which could lead to a significantly enhanced rate of singly produced t-quarks at HERA (e{sup {+-}}p {yields} e{sup {+-}}tX). The signature of interest originates from the decay t {yields} bW{sup +} with a subsequent leptonic decay of the W-boson (W{sup +} {yields} e{sup +}{nu}{sub e}, {mu}{sup +}{nu}{sub {mu}}, {tau}{sup +}{nu}{sub {tau}}). After the final selection, one event was found in data in the combined e- and {mu}-channels, where 1.27{+-}0.15 were expected from SM predictions. The selection efficiency in these channels was 13.4{sup +1.8}{sub -0.8}% for a t-quark mass of 175 GeV. In combination with independent searches in HERA I data in both, the leptonic and hadronic channel, limits on the FCNC couplings through photon and Z-boson exchange were derived. The NLO limit {kappa}{sub tu{gamma}}<0.160{sup +0.014}{sub -0.012} at 95% CL for a t-quark mass of 175 GeV is the most stringent so far. Together with the most stingent limit on v{sub tuz} of 0.37, an upper cross section limit of {sigma}{sub single} {sub t}<0.186{sup +0.029}{sub -0.012} pb was obtained.Also a limit on the cross section of single W-boson production of {sigma}{sub single} {sub W}<1.54{sup +0.67}{sub -0.41} pb was obtained at 95% CL. In this thesis, also a simulation study to optimise design parameters of a MAPS based vertex detector for a future ILC is presented. The study was based on the TESLA TDR. In order to evaluate the effect of different design options for the vertex detector on the physics performance of the whole detector, the reconstruction of the t-quark mass from the signal process e{sup +}e

  12. Optimising of design parameters of the TESLA vertex detector and search for events with isolated leptons and large missing transverse momentum with the ZEUS-experiment (HERA II)

    International Nuclear Information System (INIS)

    Adler, V.

    2006-06-01

    In this thesis, a search for events with isolated leptons and large missing transverse momentum at HERA is presented. Data with an integrated luminosity of 40.76 pb -1 of e + p-collisions collected with the ZEUS detector at a CMS energy of 318 GeV during the HERA II running period in the years 2003 and 2004 were used. Some extensions of the SM contain FCNC processes at tree level, which could lead to a significantly enhanced rate of singly produced t-quarks at HERA (e ± p → e ± tX). The signature of interest originates from the decay t → bW + with a subsequent leptonic decay of the W-boson (W + → e + ν e , μ + ν μ , τ + ν τ ). After the final selection, one event was found in data in the combined e- and μ-channels, where 1.27±0.15 were expected from SM predictions. The selection efficiency in these channels was 13.4 +1.8 -0.8 % for a t-quark mass of 175 GeV. In combination with independent searches in HERA I data in both, the leptonic and hadronic channel, limits on the FCNC couplings through photon and Z-boson exchange were derived. The NLO limit κ tuγ +0.014 -0.012 at 95% CL for a t-quark mass of 175 GeV is the most stringent so far. Together with the most stingent limit on v tuz of 0.37, an upper cross section limit of σ single t +0.029 -0.012 pb was obtained.Also a limit on the cross section of single W-boson production of σ single W +0.67 -0.41 pb was obtained at 95% CL. In this thesis, also a simulation study to optimise design parameters of a MAPS based vertex detector for a future ILC is presented. The study was based on the TESLA TDR. In order to evaluate the effect of different design options for the vertex detector on the physics performance of the whole detector, the reconstruction of the t-quark mass from the signal process e + e - →t anti t in the all-hadronic decay channel was used. The fast simulation program SGV was equipped with a neural-network based heavy-flavour tagging, where the b-tagging achieved a purity of 86% at an

  13. The micro vertex detector for the anti PANDA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Esch, Simone [Forschungszentrum Juelich (Germany); Collaboration: PANDA-Collaboration

    2015-07-01

    The anti PANDA detector is one of the main experiments at the upcoming Facility for Antiproton and Ion Research (FAIR), which is under construction in Darmstadt, Germany. The fixed-target experiment will explore anti pp annihilations with intense, phase space-cooled beams with momenta between 1.5 and 15 GeV/c. One aim of the detector is to perform high precision measurements of particles like excited charmonium and D mesons. Essential for background suppression is the tagging of D mesons by measuring their decay point. Therefore, a Micro Vertex Detector (MVD) is planned at anti PANDA as the innermost tracking detector. The MVD aims to reconstruct vertices with a resolution better than 100 μm to cope with the decay length of the D{sup ±} mesons (cτ=315 μm) produced with a mean βγ=2. The detector consists of silicon pixel and double-sided silicon strip detectors, arranged in four barrel layers and six disk layers. An overview of the MVD is given in this talk. Recent developments like laboratory and testbeam results of the current pixel front-end ASIC prototype ToPix 4 are shown. The concept of the newly developed strip front-end ASIC PASTA is presented.

  14. Silicon micro-vertex detector for Belle II

    International Nuclear Information System (INIS)

    Mohanty, Gagan

    2013-01-01

    The Belle experiment at the KEK B-factory is Japan provided the landmark experimental confirmation of CP violation mechanism within the standard model that led to the physics Nobel prize in 2008. In its second phase, called Belle II, it would seek for the holy-grail of new physics using rare decays of B and D mesons and tau leptons as a probe, in complimentary to the direct searches carried out with the LHC experiments. An important component of this upgrade is to replace the innermost subdetector, namely the silicon micro-vertex detector (SVD). The new SVD will, like the old one, consist of four layers of double-sided silicon strip detector, but made from 6âĂİ wafers and located at higher radii as a novel, two-layer DEPFET pixel detector will be inserted very dose to the beam- pipe. Starting with the physics motivation, we discuss the design concept, fabrication and the Indian contributions toward the Belle II SVD. (author)

  15. Simulations with the PANDA micro-vertex-detector

    International Nuclear Information System (INIS)

    Kliemt, Ralf

    2013-01-01

    The PANDA experiment will be built at the upcoming FAIR facility at GSI in Darmstadt, featuring antiproton-proton reactions hadron physics in a medium energy range. Charm physics will play an important role and therefore secondary decays relatively close to the interaction zone as well. The MVD will be the detector closest to these and will provide high-quality vertex position measurements. Alongside the detector layout and hardware development a detailed detector simulation and reconstruction software is required. This work contains the detailed description and the performance studies of the software developed for the MVD. Furthermore, vertexing tools are introduced and their performance is studied for the MVD.

  16. Simulations with the PANDA micro-vertex-detector

    Energy Technology Data Exchange (ETDEWEB)

    Kliemt, Ralf

    2013-07-17

    The PANDA experiment will be built at the upcoming FAIR facility at GSI in Darmstadt, featuring antiproton-proton reactions hadron physics in a medium energy range. Charm physics will play an important role and therefore secondary decays relatively close to the interaction zone as well. The MVD will be the detector closest to these and will provide high-quality vertex position measurements. Alongside the detector layout and hardware development a detailed detector simulation and reconstruction software is required. This work contains the detailed description and the performance studies of the software developed for the MVD. Furthermore, vertexing tools are introduced and their performance is studied for the MVD.

  17. Development of new assembly techniques for a silicon micro-vertex detector unit using the flip-chip bonding method

    International Nuclear Information System (INIS)

    Saitoh, Y.; Takeuchi, H.; Mandai, M.; Kanazawa, H.; Yamanaka, J.; Miyahara, S.; Kamiya, M.; Fujita, Y.; Higashi, Y.; Ikeda, H.; Ikeda, M.; Koike, S.; Matsuda, T.; Ozaki, H.; Tanaka, M.; Tsuboyama, T.; Avrillon, S.; Okuno, S.; Haba, J.; Hanai, H.; Mori, S.; Yusa, K.; Fukunaga, C.

    1994-01-01

    Full-size models of a detector unit for a silicon micro-vertex detector were built for the KEK B factory. The Flip-Chip Bonding (FCB) method using a new type anisotropic conductive film was examined. The structure using the FCB method successfully provides a new architecture for the silicon micro-vertex detector unit. (orig.)

  18. The Micro-Vertex-Detector for the P-bar ANDA experiment

    International Nuclear Information System (INIS)

    Zotti, Laura

    2013-01-01

    P-bar ANDA is a fixed target experiment that will be carried out at the future FAIR facility. P-bar ANDA will provide an excellent tool to address fundamental question in the field of hadronic physics, with a physic program that extends from the investigation of QCD (providing insight in the mechanisms of mass generation and confinement) to the test of fundamental symmetries. The Micro-Vertex-Detector located in the innermost part of the central tracking system will be composed by hybrid pixel and double-sided micro-strip silicon detectors. The Micro-Vertex-Detector will play an important role for the P-bar ANDA physics goals. The possibility to reconstruct the secondary vertices and the applicability of a precise D meson tagging is essential for the spectroscopy in the open charm sector and the charmonium mass region. To this aim the Micro-Vertex-Detector features a spatial resolution better than 100μm, a time resolution better than 20ns, a limited material budget, and a high data rate capability in a triggerless environment. An overview of the Micro-Vertex-Detector related to the physics goals will be presented.

  19. The study of D{sup {+-}} and D{sup 0} meson production in deep inelastic scattering at HERA II with the ZEUS detector

    Energy Technology Data Exchange (ETDEWEB)

    Nicholass, Daniel

    2008-12-15

    Installed in 2000/2001, the ZEUS micro vertex detector provided the capability to reconstruct secondary vertices displaced from the primary by distances of the order 100 {mu}m. In order to be useful for tagging heavy flavour mesons the micro vertex detector was aligned with a combination of tracks from cosmic events and ep events in the HERA collider. This thesis presents measurements of D{sup {+-}} and D{sup 0} meson production obtained with the ZEUS detector at HERA using an integrated luminosity of 133.6 pb{sup -1}. The measurements cover the kinematic range 5 < Q{sup 2} < 1000 GeV{sup 2}, 0.02 < y < 0.7, 1.5 < p{sub T}{sup D} < 15 GeV and vertical stroke {eta}{sup D} vertical stroke < 1.6. Combinatorial background to the D meson signals is reduced by using the ZEUS micro vertex detector to reconstruct displaced secondary vertices. Production cross sections are compared with the predictions of next-to-leading order QCD which is found to describe the data well. Measurements are extrapolated to the full kinematic phase space in order to obtain the open charm contribution, F{sub 2}{sup c} {sup anti} {sup c}, to the proton structure function, F{sub 2}. (orig.)

  20. The ZEUS central tracking detector. Der zentrale Spuren-Detektor von ZEUS

    Energy Technology Data Exchange (ETDEWEB)

    Saxon, D H

    1989-12-01

    The Central Tracking Detector (CTD) of ZEUS covers a wide angular range, whilst the Forward Detector - comprising the Forward Tracking Detector (FTD) and electron identification by transition radiation - concentrates on the important forward cone. The RTD (Rear Tracking Detector) provides accurate angle measurement of the recoil electron and the vertex detector (VXD) aims to find particles from heavy flavour decay. To measure momentum accurately the CTD sits in a high magnetic field (B=1,8 T) within the ZEUS calorimeter. (orig./HSI).

  1. A MAPS Based Micro-Vertex Detector for the STAR Experiment

    Science.gov (United States)

    Schambach, Joachim; Anderssen, Eric; Contin, Giacomo; Greiner, Leo; Silber, Joe; Stezelberger, Thorsten; Sun, Xiangming; Szelezniak, Michal; Videbaek, Flemming; Vu, Chinh; Wieman, Howard; Woodmansee, Sam

    For the 2014 heavy ion run of RHIC a new micro-vertex detector called the Heavy Flavor Tracker (HFT) was installed in the STAR experiment. The HFT consists of three detector subsystems with various silicon technologies arranged in 4 approximately concentric cylinders close to the STAR interaction point designed to improve the STAR detector's vertex resolution and extend its measurement capabilities in the heavy flavor domain. The two innermost HFT layers are placed at radii of 2.8 cm and 8 cm from the beam line. These layers are constructed with 400 high resolution sensors based on CMOS Monolithic Active Pixel Sensor (MAPS) technology arranged in 10-sensor ladders mounted on 10 thin carbon fiber sectors to cover a total silicon area of 0.16 m2. Each sensor of this PiXeL ("PXL") sub-detector combines a pixel array of 928 rows and 960 columns with a 20.7 μm pixel pitch together with front-end electronics and zero-suppression circuitry in one silicon die providing a sensitive area of ˜3.8 cm2. This sensor architecture features 185.6 μs readout time and 170 mW/cm2 power dissipation. This low power dissipation allows the PXL detector to be air-cooled, and with the sensors thinned down to 50 μm results in a global material budget of only 0.4% radiation length per layer. A novel mechanical approach to detector insertion allows us to effectively install and integrate the PXL sub-detector within a 12 hour period during an on-going multi-month data taking period. The detector requirements, architecture and design, as well as the performance after installation, are presented in this paper.

  2. Development of carbon fiber staves for the strip part of the PANDA micro vertex detector

    Energy Technology Data Exchange (ETDEWEB)

    Quagli, Tommaso; Brinkmann, Kai-Thomas [II. Physikalisches Institut, Justus-Liebig Universitaet Giessen (Germany); Fracassi, Vincenzo; Grunwald, Dirk; Rosenthal, Eberhard [ZEA-1, Forschungszentrum Juelich GmbH, Juelich (Germany); Collaboration: PANDA-Collaboration

    2015-07-01

    PANDA is a key experiment of the future FAIR facility, under construction in Darmstadt, Germany. It will study the collisions between an antiproton beam and a fixed proton or nuclear target. The Micro Vertex Detector (MVD) is the innermost detector of the apparatus and is composed of four concentric barrels and six forward disks, instrumented with silicon hybrid pixel detectors and double-sided silicon microstrip detectors; its main task is the identification of primary and secondary vertices. The central requirements include high spatial and time resolution, trigger-less readout with high rate capability, good radiation tolerance and low material budget. Because of the compact layout of the system, its integration poses significant challenges. The detectors in the strip barrels will be supported by a composite structure of carbon fiber and carbon foam; a water-based cooling system embedded in the mechanical supports will be used to remove the excess heat from the readout electronics. In this contribution the design of the barrel stave and the ongoing development of some hardware components related to its integration will be presented.

  3. A readout system for the micro-vertex-detector demonstrator for the CBM experiment at FAIR

    Energy Technology Data Exchange (ETDEWEB)

    Schrader, Christoph

    2011-06-09

    The Compressed Baryonic Matter Experiment (CBM) is a fixed target heavy ion experiment currently in preparation at the future FAIR accelerator complex in Darmstadt. The CBM experiment focuses on the measurements of diagnostic probes of the early and dense phase of the fireball at beam energies from 8 up to 45 AGeV. As observables, rare hadronic, leptonic and photonic probes are used, including open charm. Open charm will be identified by reconstructing the secondary decay vertex of the corresponding short lived particles. As the central component for track reconstruction, a detector system based on silicon semiconductor detectors is planned. The first three stations of the Silicon Tracking System (STS) make up the so-called Micro-Vertex-Detector (MVD) operating in moderate vacuum. Because of the well-balanced compromise between an excellent spatial resolution (few {mu}m), low material budget ({proportional_to}50 {mu}m Si), adequate radiation tolerance and readout speed, Monolithic Active Pixel Sensors (MAPS) based on CMOS technology are more suited than any other technology for the reconstruction of the secondary vertex in CBM. A new detector concept has to be developed. Two MVD-Demonstrator modules have been successfully tested with 120 GeV pions at the CERN-SPS. The main topic of this thesis is the development of a control and readout concept of several MVD-Demonstrator modules with a common data acquisition system. In order to achieve the required results a front-end electronics device has been developed which is capable of reading the analogue signals of two sensors on a ex-print cable. The high data rate of the MAPS sensors (1.2 Gbit per second and sensor by 50 MHz and 12 bit ADC resolution) requires a readout system which processes the data on-line in a pipeline to avoid dead times. In order to implement the pipeline processing an FPGA is used, which is located on an additional hardware platform. In order to integrate the MVD-Demonstrator readout board in the

  4. A readout system for the micro-vertex-detector demonstrator for the CBM experiment at FAIR

    International Nuclear Information System (INIS)

    Schrader, Christoph

    2011-01-01

    The Compressed Baryonic Matter Experiment (CBM) is a fixed target heavy ion experiment currently in preparation at the future FAIR accelerator complex in Darmstadt. The CBM experiment focuses on the measurements of diagnostic probes of the early and dense phase of the fireball at beam energies from 8 up to 45 AGeV. As observables, rare hadronic, leptonic and photonic probes are used, including open charm. Open charm will be identified by reconstructing the secondary decay vertex of the corresponding short lived particles. As the central component for track reconstruction, a detector system based on silicon semiconductor detectors is planned. The first three stations of the Silicon Tracking System (STS) make up the so-called Micro-Vertex-Detector (MVD) operating in moderate vacuum. Because of the well-balanced compromise between an excellent spatial resolution (few μm), low material budget (∝50 μm Si), adequate radiation tolerance and readout speed, Monolithic Active Pixel Sensors (MAPS) based on CMOS technology are more suited than any other technology for the reconstruction of the secondary vertex in CBM. A new detector concept has to be developed. Two MVD-Demonstrator modules have been successfully tested with 120 GeV pions at the CERN-SPS. The main topic of this thesis is the development of a control and readout concept of several MVD-Demonstrator modules with a common data acquisition system. In order to achieve the required results a front-end electronics device has been developed which is capable of reading the analogue signals of two sensors on a ex-print cable. The high data rate of the MAPS sensors (1.2 Gbit per second and sensor by 50 MHz and 12 bit ADC resolution) requires a readout system which processes the data on-line in a pipeline to avoid dead times. In order to implement the pipeline processing an FPGA is used, which is located on an additional hardware platform. In order to integrate the MVD-Demonstrator readout board in the HADES data

  5. Vertex detectors

    International Nuclear Information System (INIS)

    Lueth, V.

    1992-07-01

    The purpose of a vertex detector is to measure position and angles of charged particle tracks to sufficient precision so as to be able to separate tracks originating from decay vertices from those produced at the interaction vertex. Such measurements are interesting because they permit the detection of weakly decaying particles with lifetimes down to 10 -13 s, among them the τ lepton and charm and beauty hadrons. These two lectures are intended to introduce the reader to the different techniques for the detection of secondary vertices that have been developed over the past decades. The first lecture includes a brief introduction to the methods used to detect secondary vertices and to estimate particle lifetimes. It describes the traditional technologies, based on photographic recording in emulsions and on film of bubble chambers, and introduces fast electronic registration of signals derived from scintillating fibers, drift chambers and gaseous micro-strip chambers. The second lecture is devoted to solid state detectors. It begins with a brief introduction into semiconductor devices, and then describes the application of large arrays of strip and pixel diodes for charged particle tracking. These lectures can only serve as an introduction the topic of vertex detectors. Time and space do not allow for an in-depth coverage of many of the interesting aspects of vertex detector design and operation

  6. ZEUS hardware control system

    Science.gov (United States)

    Loveless, R.; Erhard, P.; Ficenec, J.; Gather, K.; Heath, G.; Iacovacci, M.; Kehres, J.; Mobayyen, M.; Notz, D.; Orr, R.; Orr, R.; Sephton, A.; Stroili, R.; Tokushuku, K.; Vogel, W.; Whitmore, J.; Wiggers, L.

    1989-12-01

    The ZEUS collaboration is building a system to monitor, control and document the hardware of the ZEUS detector. This system is based on a network of VAX computers and microprocessors connected via ethernet. The database for the hardware values will be ADAMO tables; the ethernet connection will be DECNET, TCP/IP, or RPC. Most of the documentation will also be kept in ADAMO tables for easy access by users.

  7. ZEUS hardware control system

    International Nuclear Information System (INIS)

    Loveless, R.; Erhard, P.; Ficenec, J.; Gather, K.; Heath, G.; Iacovacci, M.; Kehres, J.; Mobayyen, M.; Notz, D.; Orr, R.; Sephton, A.; Stroili, R.; Tokushuku, K.; Vogel, W.; Whitmore, J.; Wiggers, L.

    1989-01-01

    The ZEUS collaboration is building a system to monitor, control and document the hardware of the ZEUS detector. This system is based on a network of VAX computers and microprocessors connected via ethernet. The database for the hardware values will be ADAMO tables; the ethernet connection will be DECNET, TCP/IP, or RPC. Most of the documentation will also be kept in ADAMO tables for easy access by users. (orig.)

  8. Study of beauty photoproduction with the ZEUS experiment at the electron-proton collider HERA

    Energy Technology Data Exchange (ETDEWEB)

    Yaguees Molina, Ana Gloria

    2008-02-22

    This thesis presents a measurement of beauty photoproduction in ep interactions at the HERA collider working at a center of mass energy of {radical}(s)=318 GeV. Two goals are followed in this thesis: first the development of a reliable algorithm (secondary vertex b-tagging) to identify jets originating from b quarks by exploiting exclusively the full micro-vertex-detector potential and the properties of the b quark, and second the determination of its performance by obtaining first measurements of inclusive beauty dijet photoproduction. The main result presented here is based on a data set collected in 2004 corresponding to an integrated luminosity of 35 pb{sup -1}. Events containing at least two jets, each having an identified secondary vertex, are selected. The fraction of events containing b-quarks is extracted using the characteristic distributions of reconstructed decay length and invariant mass of the secondary vertex. The jets are required to be within the pseudorapidity region vertical stroke {eta} vertical stroke <1.5 with transverse momenta p{sub T}>7(6) GeV/c respectively. No requirements are imposed on the b decay final state so that the measurement is kept inclusive. Total and differential cross sections as a function of transverse momentum d{sigma}/dp{sub T} and pseudorapidity d{sigma}/d{eta} of the b-jet are measured. Furthermore, the results on d{sigma}/dp{sub T} were extrapolated to obtain a measurement at the b-quark level. Motivated by the results of this exploratory analysis of beauty quark production using secondary vertex b-tagging and profiting from improvements of the ZEUS tracking software since this first analysis, a more precise measurement became possible. The new analysis, still ongoing, is based on the data set collected in 2005 by the ZEUS detector and profits of higher statistics (L=132.6 pb{sup -1}) as well as of an improved detector alignment and calibration and a better understanding of the tracking/vertexing procedures which

  9. Study of beauty photoproduction with the ZEUS experiment at the electron-proton collider HERA

    International Nuclear Information System (INIS)

    Yaguees Molina, Ana Gloria

    2008-01-01

    This thesis presents a measurement of beauty photoproduction in ep interactions at the HERA collider working at a center of mass energy of √(s)=318 GeV. Two goals are followed in this thesis: first the development of a reliable algorithm (secondary vertex b-tagging) to identify jets originating from b quarks by exploiting exclusively the full micro-vertex-detector potential and the properties of the b quark, and second the determination of its performance by obtaining first measurements of inclusive beauty dijet photoproduction. The main result presented here is based on a data set collected in 2004 corresponding to an integrated luminosity of 35 pb -1 . Events containing at least two jets, each having an identified secondary vertex, are selected. The fraction of events containing b-quarks is extracted using the characteristic distributions of reconstructed decay length and invariant mass of the secondary vertex. The jets are required to be within the pseudorapidity region vertical stroke η vertical stroke T >7(6) GeV/c respectively. No requirements are imposed on the b decay final state so that the measurement is kept inclusive. Total and differential cross sections as a function of transverse momentum dσ/dp T and pseudorapidity dσ/dη of the b-jet are measured. Furthermore, the results on dσ/dp T were extrapolated to obtain a measurement at the b-quark level. Motivated by the results of this exploratory analysis of beauty quark production using secondary vertex b-tagging and profiting from improvements of the ZEUS tracking software since this first analysis, a more precise measurement became possible. The new analysis, still ongoing, is based on the data set collected in 2005 by the ZEUS detector and profits of higher statistics (L=132.6 pb -1 ) as well as of an improved detector alignment and calibration and a better understanding of the tracking/vertexing procedures which contribute significantly to the reduction of the uncertainties of the measurements

  10. ZEUS and HERA

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    Two detectors have been proposed - H1 and ZEUS. The remainder of this article describes the proposed ZEUS setup: Zeus is a collaboration of some 300 physicists from 41 research institutes in 9 countries. The most important design consideration has been the accurate identification and measurement of produced leptons (electroweakly interacting particles) and 'jets' of hadrons (strongly interacting particles) in a 'hermetic' calorimeter which intercepts all the released energy. Two superconducting solenoids are foreseen. A thin solenoid of inner radius 86 cm and length 280 cm mounted between the central tracking detector and the outer calorimeter will provide a field of 1.8 T. In addition, a second compensating solenoid will be inserted in the rear endcap of the central iron yoke to provide the necessary corrections for the colliding beams. (orig./HSI).

  11. Design and performance studies of the micro-vertex-detector for the CBM experiment at FAIR

    International Nuclear Information System (INIS)

    Amar-Youcef, Samir

    2012-01-01

    The CBM experiment is a fixed target experiment to be installed at the future accelerator facility at GSI/FAIR. It will investigate the properties of nuclear matter at extreme conditions and its underlying strong interaction. The research of the CBM experiment, which focuses on the regime of highest net-baryon densities and moderate temperatures, is complementary to this of the experiments at RHIC/BNL (STAR) and LHC/CERN (ALICE), which mainly focuses on the regime of high energy and zero net-baryon densities. The corresponding conditions in the CBM experiment can be produced in heavy-ion collisions at beam energies between 10 and 40 AGeV. Heavy particles, as e.g. charm carrying particles, could be sensitive to the properties of the medium in the early phase of the collision. However due to the short lifetime of open charm particles, they can only be reconstructed via their decay products and the corresponding track topology. Consequently in order to reconstruct the decay vertex with a high accuracy an ultrathin detector system with excellent spatial resolution is required. For the precise vertexing a microvertex detector (MVD) is envisaged, which has to be located directly behind the target and has to operate in the vacuum. Monolithic Active Pixel Sensors (MAPS) are the most promising candidates for the underlying sensor technology for the MVD of the CBM experiment. In the context of this thesis first attempts haven been initiated in order to integrate mechanically MAPS sensors into an ultra-thin detector dedicated to the CBM experiment. The mechanical integration necessarily needs to contain the MAPS sensors, electrical services and a support structure to cool and mount the sensors. As, apart from the intrinsic properties of the sensor, the support structures contribute notably to the specific functions and properties of the detector, particular care has to be taken during its development. Its implementation is not meant to push already the limits, rather it is

  12. Design and performance studies of the micro-vertex-detector for the CBM experiment at FAIR

    Energy Technology Data Exchange (ETDEWEB)

    Amar-Youcef, Samir

    2012-04-12

    The CBM experiment is a fixed target experiment to be installed at the future accelerator facility at GSI/FAIR. It will investigate the properties of nuclear matter at extreme conditions and its underlying strong interaction. The research of the CBM experiment, which focuses on the regime of highest net-baryon densities and moderate temperatures, is complementary to this of the experiments at RHIC/BNL (STAR) and LHC/CERN (ALICE), which mainly focuses on the regime of high energy and zero net-baryon densities. The corresponding conditions in the CBM experiment can be produced in heavy-ion collisions at beam energies between 10 and 40 AGeV. Heavy particles, as e.g. charm carrying particles, could be sensitive to the properties of the medium in the early phase of the collision. However due to the short lifetime of open charm particles, they can only be reconstructed via their decay products and the corresponding track topology. Consequently in order to reconstruct the decay vertex with a high accuracy an ultrathin detector system with excellent spatial resolution is required. For the precise vertexing a microvertex detector (MVD) is envisaged, which has to be located directly behind the target and has to operate in the vacuum. Monolithic Active Pixel Sensors (MAPS) are the most promising candidates for the underlying sensor technology for the MVD of the CBM experiment. In the context of this thesis first attempts haven been initiated in order to integrate mechanically MAPS sensors into an ultra-thin detector dedicated to the CBM experiment. The mechanical integration necessarily needs to contain the MAPS sensors, electrical services and a support structure to cool and mount the sensors. As, apart from the intrinsic properties of the sensor, the support structures contribute notably to the specific functions and properties of the detector, particular care has to be taken during its development. Its implementation is not meant to push already the limits, rather it is

  13. Micro channel evaporative $CO_2$ cooling for the upgrade of the LHCb vertex detector

    CERN Document Server

    Buytaert, J; Dumps, R; Greening, E; John, M; Leflat, A; Li, Y; Mapelli, A; Nomerotski, A; Romagnoli, G; Verlaat, B

    2013-01-01

    Local thermal management of detector electronics through ultra-thin micro-structured silicon cooling plates is a very promising technique for pixel detectors in high energy physics experiments, especially at the LHC where the heavily irradiated sensors must be operated at temperatures below − 20 1 C. It combines a very high thermal ef fi ciency with a very low addition of mass and space, and suppresses all problems of CTE mismatch between the heat source and the heat sink. In addition, the use of CO 2 as evaporative coolant liquid brings all the bene fi ts of reliable and stable operation, but the high pressures involved impose additional challenges on the micro channel design and the fl uidic connectivity. A series of designs have already been prototyped and tested for LHCb. The challenges, the current status of the measurements and the solutions under development will be described

  14. A time-based front-end ASIC for the silicon micro strip sensors of the P-bar ANDA Micro Vertex Detector

    International Nuclear Information System (INIS)

    Pietro, V. Di; Brinkmann, K.-Th.; Riccardi, A.; Ritman, J.; Stockmanns, T.; Zambanini, A.; Rivetti, A.; Rolo, M.D.

    2016-01-01

    The P-bar ANDA (Antiproton Annihilation at Darmstadt) experiment foresees many detectors for tracking, particle identification and calorimetry. Among them, the innermost is the MVD (Micro Vertex Detector) responsible for a precise tracking and the reconstruction of secondary vertices. This detector will be built from both hybrid pixel (two inner barrels and six forward disks) and double-sided micro strip (two outer barrels and outer rim of the last two disks) silicon sensors. A time-based approach has been chosen for the readout ASIC of the strip sensors. The PASTA ( P-bar ANDA Strip ASIC) chip aims at high resolution time-stamping and charge information through the Time over Threshold (ToT) technique. It benefits from a Time to Digital Converter (TDC) allowing a time bin width down to 50 ps. The analog front-end was designed to serve both n-type and p-type strips and the performed simulations show remarkable performances in terms of linearity and electronic noise. The TDC consists of an analog interpolator, a digital local controller, and a digital global controller as the common back-end for all of the 64 channels

  15. A time-based front-end ASIC for the silicon micro strip sensors of the bar PANDA Micro Vertex Detector

    Science.gov (United States)

    Di Pietro, V.; Brinkmann, K.-Th.; Riccardi, A.; Ritman, J.; Rivetti, A.; Rolo, M. D.; Stockmanns, T.; Zambanini, A.

    2016-03-01

    The bar PANDA (Antiproton Annihilation at Darmstadt) experiment foresees many detectors for tracking, particle identification and calorimetry. Among them, the innermost is the MVD (Micro Vertex Detector) responsible for a precise tracking and the reconstruction of secondary vertices. This detector will be built from both hybrid pixel (two inner barrels and six forward disks) and double-sided micro strip (two outer barrels and outer rim of the last two disks) silicon sensors. A time-based approach has been chosen for the readout ASIC of the strip sensors. The PASTA (bar PANDA Strip ASIC) chip aims at high resolution time-stamping and charge information through the Time over Threshold (ToT) technique. It benefits from a Time to Digital Converter (TDC) allowing a time bin width down to 50 ps. The analog front-end was designed to serve both n-type and p-type strips and the performed simulations show remarkable performances in terms of linearity and electronic noise. The TDC consists of an analog interpolator, a digital local controller, and a digital global controller as the common back-end for all of the 64 channels.

  16. Resolution studies for the micro vertex detector of the anti PANDA experiment and the reconstruction of charmed mesons for specific hadronic channels

    International Nuclear Information System (INIS)

    Jaekel, Rene

    2009-01-01

    The PANDA experiment is planned as part of the extended GSI facility FAIR to investigate hadronic reactions in antiproton-proton annihilations. An excellent beam quality and high luminosity is expected which allows the investigation of hadronic reactions such as the spectroscopy of the charmonium system. To ensure different studies of hadronic systems an universal detector is being designed, the PANDA detector. A high resolution Micro Vertex Detector (MVD), as part of the whole setup, is an important component of the track and vertex reconstruction. A mayor part of this work were simulation studies to investigate the resolution ability of the vertex detector. For this the development and implementation of reconstruction algorithms and their integration to the track and vertex reconstruction were an essential part to allow the detailed study of the resolution of the MVD and the whole apparatus under realistic assumptions. The track and vertex reconstruction ability of the detector is shown exemplarily for the channels antiproton-proton into two charged pions and into J/ψ and photon. The expected hadronic background for physics observables requires a high selection power of the experimental setup, especially for the investigation of the charmonium system above the D anti D threshold. For this particular energy region no experimental data exist and the PANDA experiment can contribute to understand the binding of charmed mesonic systems. Charmonium states can decay to open-charm channels which provide a clear signature in the detector from the charged D-Meson decays. In this work the high selection ability of the experimental setup was investigated for two reaction channels. Under the assumption of an expected low reaction cross section the clear identification of the DD(bar) decay channel was shown, even for the presence of a huge hadronic background. This allows a clear identification of the D anti D decay channel and mayor background resources for this channel were

  17. The ZEUS data preservation project

    International Nuclear Information System (INIS)

    Malka, Janusz; Wichmann, Katarzyna

    2012-01-01

    A project to allow long term access and physics analysis of ZEUS data (ZEUS data preservation) has been established in collaboration with the DESY-IT group. In the ZEUS approach the analysis model is based on the Common Ntuple project, under development since 2006. The real data and all presently available Monte Carlo samples are being preserved in a flat ROOT ntuple format. There is ongoing work to provide the ability to simulate new, additional Monte Carlo samples also in the future. The validation framework of such a scheme using virtualisation techniques is being explored. The goal is to validate the frozen ZEUS software against future changes in hardware and operating system. A cooperation between ZEUS, DESY-IT and the library was established for document digitisation and long-term preservation of collaboration web pages. Part of the ZEUS internal documentation has already been stored within the HEP documentation system INSPIRE. Existing digital documentation, needed to perform physics analysis also in the future, is being centralised and completed.

  18. Design and development of a vertex reconstruction for the CMS (Compact Muon Solenoid) data. Study of gaseous and silicon micro-strips detectors (MSGC)

    International Nuclear Information System (INIS)

    Moreau, St.

    2002-12-01

    The work presented in this thesis has contributed to the development of the Compact Muon Solenoid detector (CMS) that will be installed at the future Large Hadron Collider (LHC) which will start running in summer 2007. This report is organised in three parts: the study of gaseous detectors and silicon micro-strips detectors, and a development of a software for the reconstruction and analysis of CMS data in the framework of ORCA. First, the micro-strips gaseous detectors (MSGC) study was on the ultimate critical irradiation test before their substitution in the CMS tracker. This test showed a really small number of lost anodes and a stable signal to noise ratio. This test proved that the described MSGC fulfill all the requirements to be integrated in the CMS tracker. The following contribution described a study of silicon micro-strips detectors and its electronics exposed to a 40 MHz bunched LHC like beam. These tests indicated a good behaviour of the data acquisition and control system. The signal to noise ratio, the bunch crossing identification and the cluster finding efficiency had also be analysed. The last study concern the design and the development of an ORCA algorithm dedicates to secondary vertex reconstruction. This iterative algorithm aims to be use for b tagging. This part analyse also primary vertex reconstruction in events without and with pile up. (author)

  19. Design optimization of the PANDA micro-vertex-detector for high performance spectroscopy in the charm quark sector

    Energy Technology Data Exchange (ETDEWEB)

    Wuerschig, Thomas

    2011-07-19

    The PANDA experiment is one of the key projects at the future FAIR facility, which is currently under construction at GSI Darmstadt. Measurements will be performed with antiprotons using a fixed-target setup. The main scope of PANDA is the study of the strong interaction in the charm quark sector. Therefore, high precision spectroscopy of hadronic systems in this energy domain is a prerequisite. The Micro-Vertex-Detector (MVD) as innermost part of the tracking system plays an important role to achieve this goal. At present, the PANDA project has exceeded the initial phase of conceptual design studies. Based on these results, an optimization of the individual detector subsystems, and thus also for the MVD, is necessary to continue the overall detector development towards its commissioning. Therefore, a comprehensive and realistic detector model must be developed, which on the one hand fulfils the physics requirements but on the other hand also includes feasible engineering solutions. This task is the main scope of the present work. The outcome of these studies will deliver important contributions to the technical design report for the PANDA MVD, which is the next step towards the final detector assembly. In the first part of this work, main physics aspects of the charm spectroscopy are highlighted and a complete review of the experimental status in this field is given. Afterwards, all relevant details of the PANDA experiment are summarized. The conceptual design and associated hardware developments for the MVD are discussed separately in the following chapters. They deliver basic input for the performed detector optimization, which is presented in the central part. Furthermore, this section describes the development of a comprehensive detector model for the MVD and its introduction into the physics simulation framework of PANDA. The final part contains a compilation of extended simulations with the developed detector model. This includes the determination of basic

  20. Design optimization of the PANDA micro-vertex-detector for high performance spectroscopy in the charm quark sector

    International Nuclear Information System (INIS)

    Wuerschig, Thomas

    2011-01-01

    The PANDA experiment is one of the key projects at the future FAIR facility, which is currently under construction at GSI Darmstadt. Measurements will be performed with antiprotons using a fixed-target setup. The main scope of PANDA is the study of the strong interaction in the charm quark sector. Therefore, high precision spectroscopy of hadronic systems in this energy domain is a prerequisite. The Micro-Vertex-Detector (MVD) as innermost part of the tracking system plays an important role to achieve this goal. At present, the PANDA project has exceeded the initial phase of conceptual design studies. Based on these results, an optimization of the individual detector subsystems, and thus also for the MVD, is necessary to continue the overall detector development towards its commissioning. Therefore, a comprehensive and realistic detector model must be developed, which on the one hand fulfils the physics requirements but on the other hand also includes feasible engineering solutions. This task is the main scope of the present work. The outcome of these studies will deliver important contributions to the technical design report for the PANDA MVD, which is the next step towards the final detector assembly. In the first part of this work, main physics aspects of the charm spectroscopy are highlighted and a complete review of the experimental status in this field is given. Afterwards, all relevant details of the PANDA experiment are summarized. The conceptual design and associated hardware developments for the MVD are discussed separately in the following chapters. They deliver basic input for the performed detector optimization, which is presented in the central part. Furthermore, this section describes the development of a comprehensive detector model for the MVD and its introduction into the physics simulation framework of PANDA. The final part contains a compilation of extended simulations with the developed detector model. This includes the determination of basic

  1. ZEUS - standardized macros for the TPA computer

    International Nuclear Information System (INIS)

    Winde, M.

    1976-01-01

    An existing cross-assembler with macro-option was modified to allow the usage of the ZEUS macros. The ZEUS macros are understood by the assembler without prior definition by the user. ZEUS macros allow the programmer, who is obliged to code his TPA (PDP-8) programs on the assembler level to formulate his program logic as in a higher level language. ZEUS macros offer all basic elements necessary for structured programming. (author)

  2. The ARGUS vertex trigger

    International Nuclear Information System (INIS)

    Koch, N.; Kolander, M.; Kolanoski, H.; Siegmund, T.; Bergter, J.; Eckstein, P.; Schubert, K.R.; Waldi, R.; Imhof, M.; Ressing, D.; Weiss, U.; Weseler, S.

    1995-09-01

    A fast second level trigger has been developed for the ARGUS experiment which recognizes tracks originating from the interaction region. The processor compares the hits in the ARGUS Micro Vertex Drift Chamber to 245760 masks stored in random access memories. The masks which are fully defined in three dimensions are able to reject tracks originating in the wall of the narrow beampipe of 10.5 mm radius. (orig.)

  3. Study of elastic ρ0 photoproduction at HERA using the ZEUS leading proton spectrometer

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magil, S.

    1996-08-01

    The differential cross section dσ/dt for elastic ρ 0 photoproduction, γp→ρ 0 p(ρ 0 →π + π - ), has been measured in ep interactions at HERA. The squared four-momentum exchanged at the proton vertex, t, has been determined directly by measuring the momentum of the scattered proton using the ZEUS leading proton spectrometer (LPS), a large scale system of silicon micro-strip detectors operating close to the HERA proton beam. The LPS allows the measurement of the momentum of high energy protons scattered at small angles with accuracies of 0.4% for the longitudinal momentum and 5 MeV for the transverse momentum. Photoproduction of ρ 0 mesons has been investigated in the interval 0.073 2 , for photon virtualities q 2 2 and photon-proton centre-of-mass energies between 50 and 100 GeV. In the measured range, the t distribution exhibits an exponential shape with a slope parameter b=9.8±0.8(stat.)±1.1(syst.) GeV -2 . The use of the LPS eliminates the contamination from events with diffractive dissociation of the proton into low mass states. (orig.)

  4. ZEXP - expert system for ZEUS

    International Nuclear Information System (INIS)

    Behrens, U.; Flasinski, M.; Hagge, L.

    1992-10-01

    The proper and timely reactions to errors occurring in the online data-acquisition (DAQ) system are necessary conditions of smooth data taking during the experiment runs. Since the Eventbuilder (EVB) is a central part of the ZEUS DAQ system, it is the best place for monitoring, detecting, and recognizing erroneous behaviour. ZEXP is a software tool for upgrading the DAQ system performance. The pattern recognition methodology used for designing one of its two main modules is discussed. The general design ideas of the system and some preliminary results from the summarizing run module are presented, as well. (orig.)

  5. On the determination of track parameters with the forward drift chambers of the ZEUS detector. Zur Bestimmung von Spurparametern mit den Vorwaertsdriftkammern des ZEUS-Detektors

    Energy Technology Data Exchange (ETDEWEB)

    Guenzel, T F

    1989-01-01

    The ep-collider HERA at DESY in Hamburg will probe unexplored kinematical regions of the deep-inelastic electron-proton-scattering. The ZEUS-Collaboration develops a detector to study the physical interactions of the incoming particles. Among the requirements of the ZEUS-detector a good momentum resolution of the particle tracks in the inner detector resp. forward tracking detector (FTD) is necessary. The behaviour of the tracks in the forward tracking detector is determined by the lorentzboost ({beta}=0.93) in forward direction and by the inhomogeneous magnetic field in the FTD, which is mainly parallel to the beampipe-axis. In this thesis all studies regard only the FTD (not including VXD or CTD) for the momentum determination. Two scenarios are considered to determine the limits of momentum measurability in the FTD. The results show that the determination of the momentum in the FTD is only possible with the (exact) knowledge of the vertex position, where the tracks come from. The functional dependence of the track parameters at the vertex on the track parameters at the first FTD-module was intensively studied. Disconnected ambiguities are not found. A track model for tracks in the FTD is developed without regarding multiple scattering. The momentum determination of a track is mainly based on the track part between the first FTD-module and the vertex. A momentum resolution of {sigma}p/P=0.008 P-0.0025 P can be achieved depending on the polar angle (relative to the beampipe-axis) of the track at the vertex. Finally the influence of the multiple scattering between the first FTD-module and the vertex on the momentum resolution is estimated. The increase of the dead material for small polar angles restricts the area of acceptable momentum resolution to polar angles of {lambda}>180 mrad. (orig.).

  6. Design of the micro vertex detector of the CBM experiment. Development of a detector response model and feasibility studies of open charm measurement

    International Nuclear Information System (INIS)

    Dritsa, Christina Anna

    2011-01-01

    The PhD addresses the feasibility of reconstructing open charm mesons with the Compressed Baryonic Matter experiment, which will be installed at the FAIR accelerator complex at Darmstadt/Germany. The measurements will be carried out by means of a dedicated Micro Vertex Detector (MVD), which will be equipped with CMOS Monolithic Active Pixel Sensors (MAPS). The feasibility of reconstructing the particles with a proposed detector setup was studied. To obtain conclusive results, the properties of a MAPS prototype were measured in a beam test at the CERN-SPS accelerator. Based on the results achieved, a dedicated simulation software for the sensors was developed and implemented into the software framework of CBM (CBMRoot). Simulations on the reconstruction of D 0 -mesons were carried out. It is concluded that the reconstruction of those particles is possible. The PhD introduces the physics motivation of doing open charm measurements, represents the results of the measurements of MAPS and introduces the innovative simulation model for those sensors as much as the concept and results of simulations of the D 0 reconstruction.

  7. Development of the ZEUS central tracking detector

    Science.gov (United States)

    Brooks, C. B.; Bullock, F. W.; Cashmore, R. J.; Devenish, R. C.; Foster, B.; Fraser, T. J.; Gibson, M. D.; Gilmore, R. S.; Gingrich, D.; Harnew, N.; Hart, J. C.; Heath, G. P.; Hiddleston, J.; Holmes, A. R.; Jamdagni, A. K.; Jones, T. W.; Llewellyn, T. J.; Long, K. R.; Lush, G. J.; Malos, J.; Martin, N. C.; McArthur, I.; McCubbin, N. A.; McQuillan, D.; Miller, D. B.; Mobayyen, M. M.; Morgado, C.; Nash, J.; Nixon, G.; Parham, A. G.; Payne, B. T.; Roberts, J. H. C.; Salmon, G.; Saxon, D. H.; Sephton, A. J.; Shaw, D.; Shaw, T. B.; Shield, P. D.; Shulman, J.; Silvester, I.; Smith, S.; Strachan, D. E.; Tapper, R. J.; Tkaczyk, S. M.; Toudup, L. W.; Wallis, E. W.; Wastie, R.; Wells, J.; White, D. J.; Wilson, F. F.; Yeo, K. L.; ZEUS-UK Collaboration

    1989-11-01

    The design concept and development of the ZEUS central tracking detector is described. This is a cylindrical drift chamber designed for track reconstruction, electron identification and event triggering in a high-crossing-rate, high-magnetic-field environment.

  8. Development of the ZEUS central tracking detector

    International Nuclear Information System (INIS)

    Brooks, C.B.; Cashmore, R.J.; Gingrich, D.; Harnew, N.; Heath, G.P.; Holmes, A.R.; Martin, N.C.; McArthur, I.; Nash, J.; Salmon, G.; Shield, P.D.; Silvester, I.; Smith, S.; Wastie, R.; Wells, J.; Jamdagni, A.K.; McQuillan, D.; Miller, D.B.; Mobayyen, M.M.; Shulman, J.; Toudup, L.W.

    1989-01-01

    The design concept and development of the ZEUS central tracking detector is described. This is a cylindrical drift chamber designed for track reconstruction, electron identification and event triggering in a high-crossing-rate, high-magnetic-field environment. (orig.)

  9. Magnet system studies for the Zeus experiment

    International Nuclear Information System (INIS)

    Baynham, D.E.; Coombs, R.C.; Uden, C.N.

    1985-11-01

    The ZEUS experiment will be mounted at the HERA accelerator complex currently under construction at DESY, Hamburg. A large volume of magnetic field will be required for charge selection of particles and track fitting. Two superconducting magnet systems which meet the parameters of the ZEUS Experiment are described; a small solenoid with good radiation transparency and a large aperture Helmholtz coil configuration. Basic design concepts and parameters are presented. (author)

  10. Design and development of a vertex reconstruction for the CMS (Compact Muon Solenoid) data. Study of gaseous and silicon micro-strips detectors (MSGC); Conception d'un algorithme de reconstruction de vertex pour les donnees de CMS. Etude de detecteurs gazeux (MSGC) et silicium a micropistes

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, St

    2002-12-01

    The work presented in this thesis has contributed to the development of the Compact Muon Solenoid detector (CMS) that will be installed at the future Large Hadron Collider (LHC) which will start running in summer 2007. This report is organised in three parts: the study of gaseous detectors and silicon micro-strips detectors, and a development of a software for the reconstruction and analysis of CMS data in the framework of ORCA. First, the micro-strips gaseous detectors (MSGC) study was on the ultimate critical irradiation test before their substitution in the CMS tracker. This test showed a really small number of lost anodes and a stable signal to noise ratio. This test proved that the described MSGC fulfill all the requirements to be integrated in the CMS tracker. The following contribution described a study of silicon micro-strips detectors and its electronics exposed to a 40 MHz bunched LHC like beam. These tests indicated a good behaviour of the data acquisition and control system. The signal to noise ratio, the bunch crossing identification and the cluster finding efficiency had also be analysed. The last study concern the design and the development of an ORCA algorithm dedicates to secondary vertex reconstruction. This iterative algorithm aims to be use for b tagging. This part analyse also primary vertex reconstruction in events without and with pile up. (author)

  11. STAR Vertex Detector Upgrade Development

    International Nuclear Information System (INIS)

    Greiner, Leo C.; Matis, Howard S.; Stezelberger, Thorsten; Vu, Chinh Q.; Wieman, Howard; Szelezniak, Michal; Sun, Xiangming

    2008-01-01

    We report on the development and prototyping efforts undertaken with the goal of producing a micro-vertex detector for the STAR experiment at the RHIC accelerator at BNL. We present the basic detector requirements and show a sensor development path, conceptual mechanical design candidates and readout architecture. Prototyping and beam test results with current generation MimoSTAR-2 sensors and a readout system featuring FPGA based on-the-fly hit finding and data sparsification are also presented

  12. Vertex reconstruction in CMS

    International Nuclear Information System (INIS)

    Chabanat, E.; D'Hondt, J.; Estre, N.; Fruehwirth, R.; Prokofiev, K.; Speer, T.; Vanlaer, P.; Waltenberger, W.

    2005-01-01

    Due to the high track multiplicity in the final states expected in proton collisions at the LHC experiments, novel vertex reconstruction algorithms are required. The vertex reconstruction problem can be decomposed into a pattern recognition problem ('vertex finding') and an estimation problem ('vertex fitting'). Starting from least-squares methods, robustifications of the classical algorithms are discussed and the statistical properties of the novel methods are shown. A whole set of different approaches for the vertex finding problem is presented and compared in relevant physics channels

  13. Vertex Reconstruction in CMS

    CERN Document Server

    Chabanat, E; D'Hondt, J; Vanlaer, P; Prokofiev, K; Speer, T; Frühwirth, R; Waltenberger, W

    2005-01-01

    Because of the high track multiplicity in the final states expected in proton collisions at the LHC experiments, novel vertex reconstruction algorithms are required. The vertex reconstruction problem can be decomposed into a pattern recognition problem ("vertex finding") and an estimation problem ("vertex fitting"). Starting from least-square methods, ways to render the classical algorithms more robust are discussed and the statistical properties of the novel methods are shown. A whole set of different approaches for the vertex finding problem is presented and compared in relevant physics channels.

  14. ZEUS contributed papers to CHEP92

    International Nuclear Information System (INIS)

    1992-10-01

    At the Computing in High Energy Physics conference, CHEP92 Annecy 21st - 25th September 1992, the ZEUS data acquisition groups contributed a number of papers, as a result of plenary, parallel and poster session contributions. These papers are appended after the index list and a figure which gives a schematic overview of the acquisition system. The papers give up-to-date information concerning the ZEUS data acquisition system and the experience gained during the first HERA running period in 1992. (orig.)

  15. Beauty in photoproduction at HERA II with the ZEUS detector

    Energy Technology Data Exchange (ETDEWEB)

    Boutle, Sarah

    2010-02-15

    The production of beauty quarks in ep collisions should be accurately calculable in perturbative Quantum Chromodynamics (QCD) since the large mass of the b quark provides a hard scale. Therefore it is interesting to compare such predictions to results using photoproduction events where a low-virtuality photon, emitted by the incoming lepton, collides with a parton from the incoming proton. A measurement of beauty in photoproduction has been made at HERA with the ZEUS detector using an integrated luminosity of 126 pb{sup -}1. Beauty was identified in events with a muon in the final state by using the transverse momentum of the muon relative to the closest jet. Lifetime information from the silicon vertex detector was also used; the impact parameter of the muon with respect to the primary vertex was exploited to discriminate between signal and background. Cross sections for beauty production as a function of the muon and the jet variables were measured and compared to QCD predictions and to previous measurements. The data were found to be well described by the predictions from next-to-leading-order QCD. The dijet sample of beauty photoproduction events was also used to study higher-order QCD topologies. At leading order, the two jets in the event are produced back-to-back in azimuthal angle, such that {delta}{phi}{sup jj}={phi}{sup j1}-{phi}{sup j2}={pi}. Additional soft radiation causes small azimuthal decorrelations, whilst {delta}{phi}{sup jj} significantly lower than {pi} is evidence of additional hard radiation. In this thesis, the cross section versus {delta}{phi}{sup jj} for beauty photoproduction and the comparison to NLO QCD predictions and Monte Carlo models are presented. (orig.)

  16. Beauty in photoproduction at HERA II with the ZEUS detector

    International Nuclear Information System (INIS)

    Boutle, Sarah

    2010-02-01

    The production of beauty quarks in ep collisions should be accurately calculable in perturbative Quantum Chromodynamics (QCD) since the large mass of the b quark provides a hard scale. Therefore it is interesting to compare such predictions to results using photoproduction events where a low-virtuality photon, emitted by the incoming lepton, collides with a parton from the incoming proton. A measurement of beauty in photoproduction has been made at HERA with the ZEUS detector using an integrated luminosity of 126 pb - 1. Beauty was identified in events with a muon in the final state by using the transverse momentum of the muon relative to the closest jet. Lifetime information from the silicon vertex detector was also used; the impact parameter of the muon with respect to the primary vertex was exploited to discriminate between signal and background. Cross sections for beauty production as a function of the muon and the jet variables were measured and compared to QCD predictions and to previous measurements. The data were found to be well described by the predictions from next-to-leading-order QCD. The dijet sample of beauty photoproduction events was also used to study higher-order QCD topologies. At leading order, the two jets in the event are produced back-to-back in azimuthal angle, such that Δφ jj =φ j1 -φ j2 =π. Additional soft radiation causes small azimuthal decorrelations, whilst Δφ jj significantly lower than π is evidence of additional hard radiation. In this thesis, the cross section versus Δφ jj for beauty photoproduction and the comparison to NLO QCD predictions and Monte Carlo models are presented. (orig.)

  17. A QCD analysis of ZEUS diffractive data

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)

    2009-11-15

    ZEUS inclusive diffractive cross-section measurements have been used in a DGLAP next-to-leading-order QCD analysis to extract the diffractive parton distribution functions. Data on diffractive dijet production in deep inelastic scattering have also been included to constrain the gluon density. Predictions based on the extracted parton densities are compared to diffractive charm and dijet photoproduction data. (orig.)

  18. A QCD analysis of ZEUS diffractive data

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2009-11-01

    ZEUS inclusive diffractive cross-section measurements have been used in a DGLAP next-to-leading-order QCD analysis to extract the diffractive parton distribution functions. Data on diffractive dijet production in deep inelastic scattering have also been included to constrain the gluon density. Predictions based on the extracted parton densities are compared to diffractive charm and dijet photoproduction data. (orig.)

  19. Measurement of beauty quark cross sections in photoproduction with the ZEUS experiment at the electron-proton collider HERA

    International Nuclear Information System (INIS)

    Gutsche, O.

    2005-03-01

    This thesis measures photoproduction cross sections of semi-leptonically decaying beauty quarks into muons in dijet events: ep → ebbX → ejjμX The p T rel method is used in pre- and post-upgrade running periods to identify beauty quarks. Afterwards, these results are used to explore the applicability of the impact parameter method in the post-upgrade running periods. The technical task of this thesis consisted of the development of a new event display for the ZEUS detector incorporating the changes in the detector layout after the upgrade including the new micro-vertex-detector. The new solution providing event displays both for the pre- and post-upgrade running periods is presented by describing the visualisation concept and the implementation. In the following, a brief description of the structure of the cross section measurements and the study of the impact parameter method is given. In the pre-upgrade running periods, a data sample of 110 pb -1 is used to measure cross sections with the p T rel method. A new general muon reconstruction is established to increase the statistics significantly. The experience from the pre-upgrade running periods is then transferred to the post-upgrade running periods to measure first beauty quark cross sections using the p T rel method with the upgraded detector in a data sample of 40 pb -1 . The comparison between pre- and post-upgrade results establishes a post-upgrade event sample with known beauty content which is suitable for comparisons of the two beauty quark identification methods. A first study of the applicability of the impact parameter method concludes the investigation of beauty quark production after the upgrade. (orig.)

  20. Calibration of the ZEUS 6 m tagger

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Matthias

    2008-11-15

    In the last period of the HERA running, data were taken with the ZEUS detector to measure directly the longitudinal structure function of the proton and to determine the total photoproduction cross section. The identification of electrons from photoproduction events, in which an electron interacts with a proton and is scattered at very small angles, is essential for both the measurements. The electrons were detected using a small electromagnetic calorimeter, the 6 m tagger, which as located near the beam pipe at {approx} 6m from the ep interaction point. A method for the calibration and reconstruction of electromagnetic showers in the 6m tagger was developed and the energy acceptance range and the resolution of the 6 m tagger was measured. Furthermore, the photon acceptance and the energy resolution of a different electromagnetic calorimeter used for the luminosity measurement at ZEUS were analyzed using the 6 m tagger. (orig.)

  1. Calibration of the ZEUS 6 m tagger

    International Nuclear Information System (INIS)

    Schroeder, Matthias

    2008-11-01

    In the last period of the HERA running, data were taken with the ZEUS detector to measure directly the longitudinal structure function of the proton and to determine the total photoproduction cross section. The identification of electrons from photoproduction events, in which an electron interacts with a proton and is scattered at very small angles, is essential for both the measurements. The electrons were detected using a small electromagnetic calorimeter, the 6 m tagger, which as located near the beam pipe at ∼ 6m from the ep interaction point. A method for the calibration and reconstruction of electromagnetic showers in the 6m tagger was developed and the energy acceptance range and the resolution of the 6 m tagger was measured. Furthermore, the photon acceptance and the energy resolution of a different electromagnetic calorimeter used for the luminosity measurement at ZEUS were analyzed using the 6 m tagger. (orig.)

  2. The performance of the ZEUS calorimeter

    International Nuclear Information System (INIS)

    Crittenden, J.A.

    1994-12-01

    The ZEUS experiment has now completed its third year of operation at the electron-proton collider HERA. The uranium/scintillator sampling calorimeter surrounding the inner tracking detectors has proven an essential component for the online triggering algorithms, for offline event-type identification, for kinematic variable reconstruction, and for a ariety of physics analyses. This paper summarizes the experimental context, the operating characteristics, the calibration techniques, and the performance of the calorimeter during its first three years of operation. (orig.)

  3. Development of a free-running readout ASIC for the PANDA micro vertex detector and investigation of the performance to reconstruct anti pp → anti Ξ"+Ξ"-(1690)

    International Nuclear Information System (INIS)

    Zambanini, Andre

    2015-01-01

    The PANDA experiment is a multi-purpose particle detector, investigating hadron physics topics in the strange and charm quark mass regime. PANDA will measure antiproton-proton annihilation reactions at the FAIR complex, which is currently under construction. Caused by the initial reaction, signal and background events are similar to each other. Hence, self-triggering readout electronics is required throughout all sub-detectors. The innermost sub-detector, the Micro Vertex Detector, is based on silicon sensors with pixel and microstrip segmentation. This thesis describes the development of a readout solution (PASTA) for the microstrip sensors and the preparations for a characterization setup to perform laboratory measurements with this readout prototype. Furthermore, an exploratory study on the reconstructability of the reaction anti pp→ anti Ξ"+Ξ"-(1690) with PANDA's software framework is presented.

  4. Development of a free-running readout ASIC for the PANDA micro vertex detector and investigation of the performance to reconstruct anti pp → anti Ξ{sup +}Ξ{sup -}(1690)

    Energy Technology Data Exchange (ETDEWEB)

    Zambanini, Andre

    2015-12-08

    The PANDA experiment is a multi-purpose particle detector, investigating hadron physics topics in the strange and charm quark mass regime. PANDA will measure antiproton-proton annihilation reactions at the FAIR complex, which is currently under construction. Caused by the initial reaction, signal and background events are similar to each other. Hence, self-triggering readout electronics is required throughout all sub-detectors. The innermost sub-detector, the Micro Vertex Detector, is based on silicon sensors with pixel and microstrip segmentation. This thesis describes the development of a readout solution (PASTA) for the microstrip sensors and the preparations for a characterization setup to perform laboratory measurements with this readout prototype. Furthermore, an exploratory study on the reconstructability of the reaction anti pp→ anti Ξ{sup +}Ξ{sup -}(1690) with PANDA's software framework is presented.

  5. The LHCb VERTEX LOCATOR performance and VERTEX LOCATOR upgrade

    International Nuclear Information System (INIS)

    Rodríguez Pérez, P

    2012-01-01

    LHCb is an experiment dedicated to the study of new physics in the decays of beauty and charm hadrons at the Large Hadron Collider (LHC) at CERN. The Vertex Locator (VELO) is the silicon detector surrounding the LHCb interaction point. The detector operates in a severe and highly non-uniform radiation environment. The small pitch and analogue readout result in a best single hit precision of 4 μm. The upgrade of the LHCb experiment, planned for 2018, will transform the entire readout to a trigger-less system operating at 40 MHz event rate. The vertex detector will have to cope with radiation levels up to 10 16 1 MeVn eq /cm 2 , more than an order of magnitude higher than those expected at the current experiment. A solution is under development with a pixel detector, based on the Timepix/Medipix family of chips with 55 x 55 μm pixels. In addition a micro-strip solution is also under development, with finer pitch, higher granularity and lower mass than the current detector. The current status of the VELO will be described together with recent testbeam results.

  6. The physics analysis environment of the ZEUS experiment

    International Nuclear Information System (INIS)

    Bauerdick, L.A.T.; Derugin, O.; Gilkinson, D.; Kasemann, M.; Manczak, O.

    1995-12-01

    The ZEUS Experiment has over the last three years developed its own model of the central computing environment for physics analysis. This model has been designed to provide ZEUS physicists with powerful and user friendly tools for data analysis as well as to be truly scalable and open. (orig.)

  7. The pipelined readout for the ZEUS calorimeter

    International Nuclear Information System (INIS)

    Hervas, L.

    1991-01-01

    The electron-proton storage ring complex HERA under construction at DESY in Hamburg is the first machine of a new generation of colliders. Since physics to be studied at HERA (covered in chapter 2) base on the precise measurement of kinematic variables over a very large range of energies, a foremost emphasis is set in calorimetry. After long studies and an ambitious test program, the ZEUS collaboration has built a high resolution depleted uranium-scintillator calorimeter with photomultiplier readout, the state of the art in detectors of this type. In chapter 3 the principles of calorimetry are reviewed and the construction of the ZEUS calorimeter is described. Mainly due to the large dynamic range and the short bunch crossing times a novel concept for the readout in an analog pipelined fashion had to be designed. This concept is explained in chapter 4. The solid state implementation of the pipeline required two integrated circuits which were developed specially for the ZEUS calorimeter in collaboration with an electronics research institute and produced by industry. The design and construction of these devices and the detailed testing which has been performed for properties critical in the readout is covered in chapters 5 and 6. The whole pipelined readout is a complicated setup with many steps and collaborating systems. Its implementation and the information to operate it are covered in chapter 7. Finally the concepts presented and the applications discussed have been installed and tested on a test beam calibration experiment. There, the modules of the calorimeter have been calibrated. Chapter 8 presents results from these measurements which show excellent performance of the electronics as well as optimal properties of the calorimeter modules. (orig./HSI)

  8. The ZEUS second level calorimeter trigger

    International Nuclear Information System (INIS)

    Jong, S.J. de.

    1990-01-01

    ZEUS is a detector for the HERA ep collider, consisting of several large components. The most important being the inner tracking detectors, which are positioned nearest to the interaction point, the calorimeter surrounding the inner tracking detectors and the muon detectors on the outside of the experimental setup. Each component will deliver a vast amount of information. In order to keep this information manageable, data is preprocessed and condensed per component and then combined to obtain the final global trigger result. The main subject of this thesis is the second level calorimeter trigger processor of the ZEUS detector. In order to be able to reject the unwanted events passing the first level, the topological event signature will have to be used at the second level. The most demanding task of the second level is the recognition of local energy depositions corresponding to isolated electrons and hadron jets. Also part of the work performed by the first level will be repeated with a higher level of accuracy. Additional information not available to the first level trigger will be processed and will be made available to the global second level trigger decision module. For the second level calorimeter trigger processor a special VME module, containing two transputers, has been developed. The second level calorimeter trigger algorithm described in this thesis was tested with simulated events, that were tracked through a computer simulation of the ZEUS detector. A part of this thesis is therefore devoted to the description of the various Monte Carlo models and the justification of the way in which they were used. (author). 132 refs.; 76 figs.; 18 tabs

  9. Report from the ZEUS Collaboration at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Weizmann Institute of Science, Rehovot (Israel)

    1994-12-01

    This is a short overview of the results obtained by the ZEUS Collaboration with data collected during HERA`s first year and corresponding to an integrated luminosity of 25 nb{sup {minus}1}. Included are the measurement of the total, partial, and {rho} photoproduction cross sections, a study of high mass diffractive photoproduction, new results from hard photoproduction where a clear signal of a direct photon contribution has been established, the measurement of the photon structure function F{sub 2}, and first results on diffractive dissociation of the virtual photon in the deep inelastic electron photon scattering. Limits on leptoquarks and excited electrons are also presented.

  10. Measurement of beauty quark production from dimuon events with the ZEUS detector at HERA II

    International Nuclear Information System (INIS)

    Bot, Danny

    2011-10-01

    In this thesis, a measurement of beauty quark production via the process ep→e'b anti bX→e'μμX in electron-proton collisions at HERA using a data sample recorded by the ZEUS detector in the years 2003-2007, corresponding to an integrated luminosity of 376 pb -1 , is presented. A low transverse momentum threshold for muon identification in combination with the large rapidity coverage of the ZEUS muon-detection system gives access to essentially the full phase space for beauty quark production. Dimuon charge correlations as well as hadronic isolation and the mass of the dimuon system were used to separate the beauty signal from backgrounds. Visible, differential and total cross sections for beauty quark production were measured and compared to next-to-leading order QCD calculations and previous measurements. In addition, a first search for QCD instanton-induced processes containing both a charm- and beauty-quark pair in dimuon events was performed. In order to differentiate between beauty and instanton events, discriminating observables sensitive to the hadronic final state, so-called event shape variables, were used in combination with the dimuon requirement. As technical part of this thesis, the reconstruction algorithm for so-called energy flow objects (EFOs) was modified. EFOs contain the combined information of primary and secondary vertex-fitted tracks as well as CAL energy measurements. The modification considers additional tracks close to but not fitted to the primary vertex and which fulfill reasonable track and impact parameter requirements. As a result, the efficiency to reconstruct muon candidates with high impact parameter values as energy flow objects was increased. (orig.)

  11. Measurement of beauty quark production from dimuon events with the ZEUS detector at HERA II

    Energy Technology Data Exchange (ETDEWEB)

    Bot, Danny

    2011-10-15

    In this thesis, a measurement of beauty quark production via the process ep{yields}e'b anti bX{yields}e'{mu}{mu}X in electron-proton collisions at HERA using a data sample recorded by the ZEUS detector in the years 2003-2007, corresponding to an integrated luminosity of 376 pb{sup -1}, is presented. A low transverse momentum threshold for muon identification in combination with the large rapidity coverage of the ZEUS muon-detection system gives access to essentially the full phase space for beauty quark production. Dimuon charge correlations as well as hadronic isolation and the mass of the dimuon system were used to separate the beauty signal from backgrounds. Visible, differential and total cross sections for beauty quark production were measured and compared to next-to-leading order QCD calculations and previous measurements. In addition, a first search for QCD instanton-induced processes containing both a charm- and beauty-quark pair in dimuon events was performed. In order to differentiate between beauty and instanton events, discriminating observables sensitive to the hadronic final state, so-called event shape variables, were used in combination with the dimuon requirement. As technical part of this thesis, the reconstruction algorithm for so-called energy flow objects (EFOs) was modified. EFOs contain the combined information of primary and secondary vertex-fitted tracks as well as CAL energy measurements. The modification considers additional tracks close to but not fitted to the primary vertex and which fulfill reasonable track and impact parameter requirements. As a result, the efficiency to reconstruct muon candidates with high impact parameter values as energy flow objects was increased. (orig.)

  12. Beam tests of the ZEUS barrel calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, A; Bienz, T; Caldwell, A; Chen, L; Derrick, M; Gialas, I; Hamri, A; Imlay, R; Kartik, S; Kim, H J; Kinnel, T; Kreutzmann, H; Li, C G; Lim, J N; Loveless, R; Lu, B; Mallik, U; McLean, K W; McNeil, R; Metcalf, W; Musgrave, B; Oh, B Y; Park, S; Parsons, J A; Reeder, D; Repond, J; Ritz, S; Roco, M T.P.; Sandler, P H; Sciulli, F; Smith, W H; Talaga, R L; Tzanakos, G; Wai, L; Wang, M Z; Whitmore, J; Wu, J; Yang, S [Argonne National Lab., IL (United States) Columbia Univ., New York, NY (United States) Nevis Labs., Irvington-on-Hudson, NY (United States) Univ. of Iowa, Iowa City, IA (United States) Louisiana State Univ., Baton Rouge, LA (United States) Ohio State Univ., Columbus, OH (United States) Pennsylvania State Univ., University Park, PA (United States) Virginia Polytechnic Inst., and State Univ., Blacksburg, VA (United States) Univ. of Wisconsin, Madison, WI (United States)

    1993-11-15

    A fully compensating uranium-scintillator calorimeter was constructed for the ZEUS detector at HERA. Several of the barrel calorimeter modules were subjected to beam tests at Fermilab before shipping them to DESY for installation. The calibrations of the modules used beams of electrons and hadrons, measuring the uniformity of the response, and checking the resolution. The runs also provided opportunity to test a large fraction of the actual ZEUS calorimeter readout system in an integrated beam environment more than one year before HERA turn on. The experiment utilized two computer controlled mechanical structures, one of which was capable of holding up to four modules in order to study shower containment, and a magnetic spectrometer with a high resolution beam tracking system. During two running periods, beams of 6 to 110 GeV containing e, [mu], [pi], and anti p were used. The results show energy resolutions of 35%/[radical]E for hadrons and 19%/[radical]E for electrons, uniformities at the 1% level, energy nonlinearity less than 1%, and equal response for electrons and hadrons. (orig.)

  13. Calibration of the ZEUS forward calorimeter

    International Nuclear Information System (INIS)

    Kraemer, M.

    1990-10-01

    The physics at the ep-collider HERA requires high resolution calorimetry calibrated with an accuracy of better than 2%. The ZEUS detector meets these conditions by means of a compensating uranium scintillator sandwich calorimeter with an energy resolution of σ/E = 35%/√E + σ cal , where σ cal is the calibration error. One of the tools to minimize σ cal is the calibration with the signals of the radioactivity of the Uranium plates (UNO). Taking UNO data every 8 hours keeps the calibration stable within ≅ 1%. The muon calibration is done employing an algorithm, that determines the most probable energy loss with a precision of ≅ 1%. The channel-to-channel fluctuations of the ratio μ/UNO for a forward calorimeter (FCAL) prototype show a spread of 5.2% for the electromagnetic calorimeter and ≅ 2.5% for the hadronic sections. Improvements in the construction of the FCAL modules decreased these fluctuations to 2.0% and ≅ 1.8% respectively. The influence of the cracks between the calorimeter modules amounts to ≅ 1.7% on average for the ZEUS geometry, if a 2 mm thick Pb-sheet is introduced between the modules. We conclude that we are able to keep σ cal below 2%. (orig.)

  14. The eventbuilder of the ZEUS experiment

    International Nuclear Information System (INIS)

    Behrens, U.; Hagge, L.; Vogel, W.O.

    1993-02-01

    The Eventbuilder of the ZEUS experiment is a real-time parallel data formatting and transport system. It combines data flows originating from various detector components and transfers them to the third level trigger processor farm. The Eventbuilder is based on an asynchronous packet-switching transputer network and uses transputer links for bulk data transfer. A high-speed 64x64 custom made crossbar switch allows dynamic linking of any detector component to any branch of third level processor nodes, offering a bandwidth of more than 24 MB/s over a distance of 100 m. The use of structured system development techniques (SA/SD) resulted in a flexible and well-partitioned system structure and guaranteed that all requirements were met. (orig.)

  15. Simulation of the D{sub s} semileptonic decay with the PANDA detector and experimental verification of the Micro-Vertex-Detector pixel readout ASIC with proton test beam

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Lu

    2016-07-14

    The PANDA experiment will study a wide range of physics topics with beams of antiprotons incident on fixed proton or complex nuclear targets. One issue is the D{sub s} semileptonic decay, which is governed by the weak and strong forces. The interaction can be parameterized by a transition form factor. The performance of PANDA to measure the decay form factor of D{sup +}{sub s}→ηe{sup +}ν{sub e} is evaluated via Monte Carlo simulation. This thesis concentrates on describing the software development and the evaluation of the expected precision. A preliminary estimate of the expected count rate is obtained. In this measurement, it is essential to reconstruct the D{sub s} semileptonic decay with high efficiency and purity in order to overcome the many orders of magnitude higher background. The Micro-Vertex-Detector plays an import role in the whole tracking system. The rate capability and tracking performance of the recent ASIC prototype for the readout of the MVD is tested using a beam of high-energy protons.

  16. Vertex routing models

    International Nuclear Information System (INIS)

    Markovic, D; Gros, C

    2009-01-01

    A class of models describing the flow of information within networks via routing processes is proposed and investigated, concentrating on the effects of memory traces on the global properties. The long-term flow of information is governed by cyclic attractors, allowing to define a measure for the information centrality of a vertex given by the number of attractors passing through this vertex. We find the number of vertices having a nonzero information centrality to be extensive/subextensive for models with/without a memory trace in the thermodynamic limit. We evaluate the distribution of the number of cycles, of the cycle length and of the maximal basins of attraction, finding a complete scaling collapse in the thermodynamic limit for the latter. Possible implications of our results for the information flow in social networks are discussed.

  17. Jet Vertex Charge Reconstruction

    CERN Document Server

    Nektarijevic, Snezana; The ATLAS collaboration

    2015-01-01

    A newly developed algorithm called the jet vertex charge tagger, aimed at identifying the sign of the charge of jets containing $b$-hadrons, referred to as $b$-jets, is presented. In addition to the well established track-based jet charge determination, this algorithm introduces the so-called \\emph{jet vertex charge} reconstruction, which exploits the charge information associated to the displaced vertices within the jet. Furthermore, the charge of a soft muon contained in the jet is taken into account when available. All available information is combined into a multivariate discriminator. The algorithm has been developed on jets matched to generator level $b$-hadrons provided by $t\\bar{t}$ events simulated at $\\sqrt{s}$=13~TeV using the full ATLAS detector simulation and reconstruction.

  18. [CII] At 1 Universe with Zeus (1 and 2)

    Science.gov (United States)

    Ferkinhoff, Carl; Hailey-Dunsheath, S.; Nikola, T.; Oberst, T.; Parshley, S.; Stacey, G.; Benford, D.; staguhn, J.

    2010-01-01

    We report the detection of the [CII] 158 micron fine structure line from six submillimeter galaxies with redshifts between 1.12 and 1.73. This more than doubles the total number of [CII] 158 micron detections reported from high redshift sources. These observations were made with the Redshift(z) and Early Universe Spectrometer(ZEUS) at the Caltech Submillimeter Observatory on Mauna Kea, Hawaii between December 2006 and March 2009. ZEUS is a background limited submm echelle grating spectrometer (Hailey-Dunsheath 2009). Currently we are constructing ZEUS-2. This new instrument will utilize the same grating but will feature a two dimensional transition-edge sensed bolometer array with SQUID multiplexing readout system enabling simultaneous background limited observations in the 200, 340,450 and 650 micron telluric windows. ZEUS-2 will allow for long slit imaging spectroscopy in nearby galaxies and a [CII] survey from z 0.25 to 2.5.

  19. Biricodar. Vertex Pharmaceuticals.

    Science.gov (United States)

    Dey, Saibal

    2002-05-01

    Vertex is developing biricodar as a chemosensitizing agent designed to restore the effectiveness of chemotherapeutic agents in tumor multidrug resistance. By November 1998, phase II trials had commenced for biricodar, in combination with chemotherapy, for five common cancer indications: breast, ovarian, soft-tissue sarcomas, small cell lung cancer and prostate cancer. Phase II trials were ongoing in January 2002. By March 2000, Vertex was the sole developer of biricodar, as an agreement made in 1996 with BioChem Pharma (now Shire Pharmaceuticals), for the development and marketing of biricodar in Canada was terminated. Biricodar is the free base compound, which also has a citrate salt analog known as VX-710-3. Vertex has published three patents, WO-09615101, WO-09636630 and WO-09736869, disclosing derivatives of biricodar that are claimed for the treatment of multidrug resistant protein and P-glycoprotein-mediated multidrug resistant tumors. In January 2002, a Banc of America analyst report forecast that biricodar had a 30% chance of reaching the market with a launch date in the second half of 2005, with peak sales estimated at $250 million.

  20. Data acquisition for the Zeus central tracking detector

    International Nuclear Information System (INIS)

    Quinton, S.; Allen, D.; Cambell, D.; Mcarthur, I.

    1990-01-01

    The Zeus experiment is being installed on the Hera electron-proton collider being built at the Desy laboratory in Hamburg. The high-beam crossover rate of the Hera machine will provide experience in data acquisition and triggering relevant to the environment of future accelerators such as the SSC. The Transputer-based data acquisition system for the Zeus central tracking detector is described

  1. Vertex algebras and algebraic curves

    CERN Document Server

    Frenkel, Edward

    2004-01-01

    Vertex algebras are algebraic objects that encapsulate the concept of operator product expansion from two-dimensional conformal field theory. Vertex algebras are fast becoming ubiquitous in many areas of modern mathematics, with applications to representation theory, algebraic geometry, the theory of finite groups, modular functions, topology, integrable systems, and combinatorics. This book is an introduction to the theory of vertex algebras with a particular emphasis on the relationship with the geometry of algebraic curves. The notion of a vertex algebra is introduced in a coordinate-independent way, so that vertex operators become well defined on arbitrary smooth algebraic curves, possibly equipped with additional data, such as a vector bundle. Vertex algebras then appear as the algebraic objects encoding the geometric structure of various moduli spaces associated with algebraic curves. Therefore they may be used to give a geometric interpretation of various questions of representation theory. The book co...

  2. The ZEUS calorimeter first level trigger

    International Nuclear Information System (INIS)

    Smith, W.H.; Ali, I.; Behrens, B.; Fordham, C.; Foudas, C.; Goussiou, A.; Jaworski, M.; Kinnel, T.; Lackey, J.; Robl, P.; Silverstein, S.; Dawson, J.W.; Krakauer, D.A.; Talaga, R.L.; Schlereth, J.L.

    1994-10-01

    The design of the ZEUS Calorimeter First Level Trigger (CFLT) is presented. The CFLT utilizes a pipelined architecture to provide trigger data for a global first leel trigger decision 5 μsec after each beam crossing, occurring every 96 nsec. The charges from 13K phototubes are summed into 1792 trigger tower pulseheights which are digitized by flash ADC's. The digital values are linearized, stored and used for sums and pattern tests. Summary data is forwarded to the Global First Level Trigger for each crossing 2 μsec after the crossing occurred. The CFLT determines the total energy, the total transverse energy, the missing energy, and the energy and number of isolated electrons and muons. It also provides information on the electromagnetic and hadronic energy deposited in various regions of the calorimeter. The CFLT has kept the experimental trigger rate below ∼200 Hz at the highest luminosity experienced at HERA. Performance studies suggest that the CFLT will keep the trigger rate below 1 kHZ against a rate of proton-beam gas interactions on the order of the 100 kHz expected at design luminosity. (orig.)

  3. The ZEUS calorimeter first level trigger

    Science.gov (United States)

    Silverstein, S.; Ali, I.; Behrens, B.; Foudas, C.; Fordham, C.; Goussiou, A.; Jaworski, M.; Lackey, J.; Reeder, D.; Robl, P.; Smith, W. H.; Vaiciulis, A.; Wodarczyk, M.; Dawson, J.; Krakauer, D.; Talaga, R.; Schlereth, J.; Zhang, H.

    1995-02-01

    An overview of the ZEUS calorimeter first level trigger is presented. The CFLT uses a pipelined architecture to accept and analyze calorimeter data for every 96 ns beam crossing interval. PMT signals are combined by analog electronics into electromagnetic and hadronic sums for 896 trigger towers. The analog sums are then digitized and analyzed. The CFLT determines the total, transverse, and missing transverse energy, identifies isolated electrons and muons, and sums energies in programmable subregions. Calculations are performed in 96 ns steps, and new data are accepted for every beam crossing. Trigger data are forwarded to the global first level trigger (GFLT) after 2 μs, allowing a GFLT accept to be issued 5 μs after the beam crossing which produced the event. Important features of the CFLT include a 12-bit effective dynamic range, extensive use of memory lookup tables for trigger calculations, fast pattern searches for isolated leptons, and low electronics noise. During the 1993 HERA run, the CFLT reduced a 50 kHz background rate to around 100 Hz.

  4. The three-photon vertex

    International Nuclear Information System (INIS)

    Delbourgo, R.

    1976-01-01

    Owing to weak interactions, the three-photon vertex is non-zero. From gauge invariance and symmetry requirements, it is proved that the C = -1P = - 1 vertex amplitudes are at least of order q 7 in the limit of soft photon momentum q and that if any two photons are placed on mass shell the form factors vanish identically. (author)

  5. Silicon vertex tracker for RHIC PHENIX experiment

    Energy Technology Data Exchange (ETDEWEB)

    Taketani, A [RIKEN, Nishina Ctr Accelerator Based Sci, Wako, Saitama, Japan; Cianciolo, Vince [ORNL; Enokizono, Akitomo [Oak Ridge National Laboratory (ORNL); PHENIX, Collaboration [The

    2010-01-01

    The PHENIX experiment at Relativistic Heavy Ion Collider will be equipped with Silicon Vertex tracker to enhance its physics capability. There are four layers of silicon sensor to reconstruct charged tracks with 50 {micro}m resolution of decay length measurement. The VTX surrounds the collision point. The inner two layers and the outer two layers are composed of 30 pixel ladders and 44 stripixel ladders, respectively. We have been developing these detectors and done a performance test with 120 GeV proton beam.

  6. Beauty production at HERA using the ZEUS experiment

    International Nuclear Information System (INIS)

    Yaguees, A

    2008-01-01

    Beauty quark production in ep collisions is being studied with the ZEUS detector at HERA. The latest measurements of beauty production in deep inelastic scattering and photoproduction regime are presented. The first measurement exploits the potential of the ZEUS microvertex detector to identify beauty in photoproduction dijet events with a muon in the final state. The second is based on statistical methods to determine the fraction of beauty in photoproduction dijet events with an electron in the final state. Finally, the first measurement by ZEUS of the beauty contribution to the proton structure function, F 2 bb, in deep inelastic scattering is presented. The three measurements are compared with QCD predictions as well as with previous results. All the results presented here are preliminary

  7. The spectrometer system for measuring ZEUS luminosity at HERA

    International Nuclear Information System (INIS)

    Helbich, M.; Ning, Y.; Paganis, S.; Ren, Z.; Schmidke, W.B.; Sciulli, F.; Schneekloth, U.; Buettner, C.; Caldwell, A.; Sutiak, J.

    2006-01-01

    The upgrade of the HERA accelerator has provided much increased collider luminosity. In turn, the improvements have necessitated a new design for the ZEUS luminosity measurements. The intense synchrotron radiation field, as well as the high probability of a bremsstrahlung photon in each bunch crossing, posed new experimental constraints. In this report, we describe how these challenges were met with the ZEUS luminosity spectrometer system. The design, testing and commissioning of the device are described, and the results from the initial operational experience are reported

  8. Intercalibration of the ZEUS high resolution and backing calorimeters

    International Nuclear Information System (INIS)

    Abramowicz, H.; Czyrkowski, H.; Derlicki, A.; Krzyzanowski, M.; Kudla, I.; Kusmierz, W.; Nowak, R.J.; Pawlak, J.M.; Rajca, A.; Stopczynski, A.; Walczak, R.; Zarnecki, A.F.; Kowalski, T.Z.

    1991-07-01

    We have studied the combined performance of two calorimeters, the high resolution uranium-scintillator prototype of the ZEUS forward calorimeter (FCAL), followed by a prototype of the coarser ZEUS backing calorimeter (BAC), made out of thick iron plates interleaved with planes of aluminium proportional chambers. The test results, obtained in an exposure of the calorimeter system to a hadron test beam at the CERN-SPS, show that the backing calorimeter does fulfil its role of recognizing the energy leaking out of the FCAL calorimeter. The measurement of this energy is feasible, if an appropriate calibration of the BAC calorimeter is performed. (orig.)

  9. Intercalibration of the ZEUS high resolution and backing calorimeters

    International Nuclear Information System (INIS)

    Abramowicz, H.; Czyrkowski, H.; Derlicki, A.; Krzyzanowski, M.; Kudla, I.; Kusmierz, W.; Nowak, R.J.; Pawlak, J.M.; Rajca, A.; Stopczynski, A.; Walczak, R.; Zarnecki, A.F.; Kowalski, T.Z.

    1992-01-01

    We have studied the combined performance of two calorimeters, the high resolution uranium-scintillator prototype of the ZEUS forward calorimeter (FCAL), followed by a prototype of the coarser ZEUS backing calorimeter (BAC), made out of thick iron plates interleaved with planes of aluminium proportional chambers. The test results, obtained in an exposure of the calorimeter system to a hadron test beam at the CERN SPS, show that the backing calorimeter does fulfil its role of recognizing the energy leaking out of the FCAL calorimeter. The measurement of this energy is feasible, if an appropriate calibration of the BAC calorimeter is performed. (orig.)

  10. Micro vertex detector design for collider geometries

    International Nuclear Information System (INIS)

    Atkinson, M.; Crennell, D.; Fisher, C.M.; Hughes, P.; Kurtz, N.

    1984-05-01

    Previously the analysis of fixed target jet events using a scintillating optical fibre target to provide a projection of the topology on the plane transverse to the event axis has been considered. It was argued that this transverse plane projection is optimal for the detection of charm or beauty particle decay vertices. The idea is generalised to a jet analysis in a collider geometry particularly when associated with a high Psub(perpendicular to) or missing Esub(T) trigger. This report proposes a simple arrangement of fibres to give high precision track elements in the transverse plane projection coupled with a fast read-out capability. The principle physics aim of the design is to provide a tag for selecting top quark jets by detecting a beauty flavoured particle in the jet. (U.K.)

  11. First Results from the LHCb Vertex Locator

    CERN Multimedia

    Borghi, S

    2010-01-01

    LHCb is a dedicated experiment to study new physics in the decays of beauty and charm hadrons at the Large Hadron Collider (LHC) at CERN. The beauty and charm hadrons are identified through their flight distance in the Vertex Locator (VELO), and hence the detector is critical for both the trigger and offline physics analyses. The VELO is the silicon detector surrounding the interaction point, and is the closest LHC vertex detector to the interaction point, located only 7 mm from the LHC beam during normal operation. The detector will operate in an extreme and highly non-uniform radiation environment. The VELO consists of two retractable detector halves with 21 silicon micro-strip tracking modules each. A module is composed of two n+-on-n 300 micron thick half disc sensors with R-measuring and Phi-measuring micro-strip geometry, mounted on a carbon fibre support paddle. The minimum pitch is approximately 40 $\\mu$m. The detector is also equipped with one n-on-p module. The detectors are operated in vacuum and a...

  12. Further development of the ZEUS Expert System: Computer science foundations of design

    International Nuclear Information System (INIS)

    Flasinski, M.

    1994-03-01

    The prototype version of the ZEUS Expert System, ZEXP, was diagnosing selected aspects of DAQ System during ZEUS running in 1993. In November 1993 ZEUS decided to extend its scope in order to cover all crucial aspects of operating the ZEUS detector (Run Control, Slow Control, Data Acquisition performance and Data Quality Monitoring). The paper summarizes fundamental assumptions concerning the design of the final version of the ZEUS Expert System, ZEX. Although the theoretical background material relates primarily to ZEX, its elements can be used for constructing other expert systems for HEP experiments. (orig.)

  13. The STAR Vertex Position Detector

    Energy Technology Data Exchange (ETDEWEB)

    Llope, W.J., E-mail: llope@rice.edu [Rice University, Houston, TX 77005 (United States); Zhou, J.; Nussbaum, T. [Rice University, Houston, TX 77005 (United States); Hoffmann, G.W. [University of Texas, Austin, TX 78712 (United States); Asselta, K. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Brandenburg, J.D.; Butterworth, J. [Rice University, Houston, TX 77005 (United States); Camarda, T.; Christie, W. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Crawford, H.J. [University of California, Berkeley, CA 94720 (United States); Dong, X. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Engelage, J. [University of California, Berkeley, CA 94720 (United States); Eppley, G.; Geurts, F. [Rice University, Houston, TX 77005 (United States); Hammond, J. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Judd, E. [University of California, Berkeley, CA 94720 (United States); McDonald, D.L. [Rice University, Houston, TX 77005 (United States); Perkins, C. [University of California, Berkeley, CA 94720 (United States); Ruan, L.; Scheblein, J. [Brookhaven National Laboratory, Upton, NY 11973 (United States); and others

    2014-09-21

    The 2×3 channel pseudo Vertex Position Detector (pVPD) in the STAR experiment at RHIC has been upgraded to a 2×19 channel detector in the same acceptance, called the Vertex Position Detector (VPD). This detector is fully integrated into the STAR trigger system and provides the primary input to the minimum-bias trigger in Au+Au collisions. The information from the detector is used both in the STAR Level-0 trigger and offline to measure the location of the primary collision vertex along the beam pipe and the event “start time” needed by other fast-timing detectors in STAR. The offline timing resolution of single detector channels in full-energy Au+Au collisions is ∼100 ps, resulting in a start time resolution of a few tens of picoseconds and a resolution on the primary vertex location of ∼1 cm.

  14. The design and construction of the ZEUS central tracking detector

    Energy Technology Data Exchange (ETDEWEB)

    Foster, B.; Malos, J.; Saxon, D.H.; Clark, D.E.; Jamdagni, A.K.; Markou, C.; Miller, D.B.; Miller, D.G.; Toudup, L.W.; Auty, C.G.; Blair, G.A.; Brooks, C.B.; Cashmore, R.J.; Hanford, A.T.; Harnew, N.; Holmes, A.R.; Linford, W.; Martin, N.C.; McArthur, I.C.; Nash, J.; Nobbs, K.N.; Wastie, R.L.; Williams, M.T.; Wilson, F.F.; Wilson, R.D.; Hart, J.C.; Hatley, R.W.; Hiddleston, J.W.; Gibson, M.D.; McCubbin, N.A.; Middleton, A.; Morrissey, M.C.; Morrow, D.; O' Brien, P.; Payne, B.T.; Roberts, J.C.H.; Shaw, T.B.; Sinclair, C.K.; Wallis, E.W.G.; White, D.J.; Yeo, K.L.; Bullock, F.W.; Dumper, J.; Fraser, T.J.; Hayes, D.; Jones, T.W.; Strachan, D.E.; Vine, I.A. (H.H. Wills Physics Lab., Univ. of Bristol (United Kingdom) Dept. of Physics and Astronomy, Univ. of Glasgow (United Kingdom) Blackett Lab., Physics Dept., Imperial Coll., London (United Kingdom) Dept. of Physics, Nuclear Physics Lab., Univ. of Oxford (United Kingdom) Rutherford Appleton Lab., Chilton (United Kingdom) Dept. of Physics an

    1994-01-15

    The mechanical, electrical and electronic design and construction of the ZEUS central tracking detector are described, together with the chamber monitoring and environmental control. This cylindrical drift chamber is designed for track reconstruction, electron identification and fast event triggering in a high beam-crossing rate, high magnetic field application. (orig.)

  15. Jet energy measurements with the ZEUS prototype calorimeter

    International Nuclear Information System (INIS)

    Kroeger, W.

    1993-01-01

    The uranium scintillator calorimeter of the ZEUS detector is designed to achieve an excellent energy calibration and the best possible energy resolution for jets. Therefore the response of the prototype calorimeter to jets has been measured using an interaction trigger. The mean response and energy resolution was measured for jets of 50 GeV - 100 GeV and compared to the one for pions. Within the ZEUS detector dead material is placed in front of the calorimeter. The influence of 4 cm and 10 cm thick aluminium absorbers in front of the calorimeter was measured. The charged multiplicity was measured in front and behind the aluminium absorber. With these multiplicities the energy loss in the absorber is corrected. The correction has been done so that the mean response with absorber is equal to the mean response without absorber. The improvement of the energy resolution is investigated. The measured results are compared with Monte Carlo simulations. (orig.) [de

  16. The Mark III vertex chamber

    International Nuclear Information System (INIS)

    Adler, J.; Bolton, T.; Bunnell, K.

    1987-07-01

    The design and construction of the new Mark III vertex chamber is described. Initial tests with cosmic rays prove the ability of track reconstruction and yield triplet resolutions below 50 μm at 3 atm using argon/ethane (50:50). Also performed are studies using a prototype of a pressurized wire vertex chamber with 8 mm diameter straw geometry. Spatial resolution of 35mm was obtained using dimethyl ether (DME) at 1 atm and 30 μm using argon/ethane (50/50 mixture) at 4 atm. Preliminary studies indicate the DME to adversely affect such materials as aluminized Mylar and Delrin

  17. Design and construction of the ZEUS barrel calorimeter

    International Nuclear Information System (INIS)

    Repond, J.

    1990-01-01

    The mechanical design and construction techniques of the barrel calorimeter for the ZEUS detector are presented. The calorimeter uses alternate layers of depleted uranium and scintillator with one radiation length sampling. The unit cell has e/h = 1 which yields an optimal energy resolution for hadronic jets. We discuss the placing of the structural components and cracks between modules. Details of the construction and assembly effort needed to realize the total calorimeter are reported. 4 figs., 1 tab

  18. The Zeus Copper/Uranium Critical Experiment at NCERC

    International Nuclear Information System (INIS)

    Sanchez, Rene G.; Hayes, David K.; Bounds, John Alan; Jackman, Kevin R.; Goda, Joetta M.

    2012-01-01

    A critical experiment was performed to provide nuclear data in a non-thermal neutron spectrum and to reestablish experimental capability relevant to Stockpile Stewardship and Technical Nuclear Forensic programs. Irradiation foils were placed at specific locations in the Zeus all oralloy critical experiment to obtain fission ratios. These ratios were compared with others from other critical assemblies to assess the degree of softness in the neutron spectrum. This critical experiment was performed at the National Criticality Experiments Research Center (NCERC) in Nevada.

  19. Fast simulation of electromagnetic showers in the ZEUS calorimeter

    International Nuclear Information System (INIS)

    Peso, J. del; Ros, E.

    1991-02-01

    We present a fast Monte Carlo algorithm for the generation of electromagnetic showers in the uranium-scintillator sampling calorimeter of the ZEUS experiment. This algorithm includes a simulation of longitudinal and transverse profiles, their fluctuations and the correlation between these fluctuations as well. The tuning of this fast Monte Carlo with data generated with EGS is described and its performance together with some applications is discussed. (orig.)

  20. Connections for Small Vertex Models

    Indian Academy of Sciences (India)

    This paper is a first attempt at calssifying connections on small vertex models i.e., commuting squares of the form displayed in (1.2) below. ... obtain necessary conditions for two such `model connections' in (2, ) to be ... Current Issue : Vol.

  1. The ARGUS silicon vertex detector

    International Nuclear Information System (INIS)

    Michel, E.; Ball, S.; Ehret, K.; Geyer, C.; Hesselbarth, J.; Hoelscher, A.; Hofmann, W.; Holzer, B.; Huepper, A.; Khan, S.; Knoepfle, K.T.; Seeger, M.; Spengler, J.; Brogle, M.; Horisberger, R.

    1994-01-01

    A silicon microstrip vertex detector has been built as an upgrade to the ARGUS detector for increased precision and efficiency in the reconstruction of decay vertices. This paper discusses the mechanical and electronic design of this device and presents first results from its successful test operation yielding an impact parameter resolution of about 18 μm. ((orig.))

  2. A Macdonald refined topological vertex

    Science.gov (United States)

    Foda, Omar; Wu, Jian-Feng

    2017-07-01

    We consider the refined topological vertex of Iqbal et al (2009 J. High Energy Phys. JHEP10(2009)069), as a function of two parameters ≤ft\\lgroup x, y \\right\\rgroup , and deform it by introducing the Macdonald parameters ≤ft\\lgroup q, t \\right\\rgroup , as in the work of Vuletić on plane partitions (Vuletić M 2009 Trans. Am. Math. Soc. 361 2789-804), to obtain ‘a Macdonald refined topological vertex’. In the limit q → t , we recover the refined topological vertex of Iqbal et al and in the limit x → y , we obtain a qt-deformation of the original topological vertex of Aganagic et al (2005 Commun. Math. Phys. 25 425-78). Copies of the vertex can be glued to obtain qt-deformed 5D instanton partition functions that have well-defined 4D limits and, for generic values of ≤ft\\lgroup q, t\\right\\rgroup , contain infinite-towers of poles for every pole present in the limit q → t .

  3. Aleph silicon microstrip vertex detector

    CERN Multimedia

    Laurent Guiraud

    1998-01-01

    This microstrip vertex locator was located at the heart of the ALEPH experiment, one of the four experiments at the Large Electron-Positron (LEP) collider. In the experiments at CERN's LEP, which ran from 1989 to 2000, modern silicon microvertex detectors, such as those used at ALEPH, monitored the production of short-lived particles close to the beam pipe.

  4. Vertex algebras and mirror symmetry

    International Nuclear Information System (INIS)

    Borisov, L.A.

    2001-01-01

    Mirror Symmetry for Calabi-Yau hypersurfaces in toric varieties is by now well established. However, previous approaches to it did not uncover the underlying reason for mirror varieties to be mirror. We are able to calculate explicitly vertex algebras that correspond to holomorphic parts of A and B models of Calabi-Yau hypersurfaces and complete intersections in toric varieties. We establish the relation between these vertex algebras for mirror Calabi-Yau manifolds. This should eventually allow us to rewrite the whole story of toric mirror symmetry in the language of sheaves of vertex algebras. Our approach is purely algebraic and involves simple techniques from toric geometry and homological algebra, as well as some basic results of the theory of vertex algebras. Ideas of this paper may also be useful in other problems related to maps from curves to algebraic varieties.This paper could also be of interest to physicists, because it contains explicit description of holomorphic parts of A and B models of Calabi-Yau hypersurfaces and complete intersections in terms of free bosons and fermions. (orig.)

  5. The CDF Silicon Vertex Detector

    International Nuclear Information System (INIS)

    Tkaczyk, S.; Carter, H.; Flaugher, B.

    1993-01-01

    A silicon strip vertex detector was designed, constructed and commissioned at the CDF experiment at the Tevatron collider at Fermilab. The mechanical design of the detector, its cooling and monitoring are presented. The front end electronics employing a custom VLSI chip, the readout electronics and various components of the SVX system are described. The system performance and the experience with the operation of the

  6. The CDF Silicon Vertex Trigger

    International Nuclear Information System (INIS)

    Dell'Orso, Mauro

    2006-01-01

    Motivations, design, performance and ongoing upgrade of the CDF Silicon Vertex Trigger are presented. The system provides CDF with a powerful tool for online tracking with offline quality in order to enhance the reach on B-physics and large P t -physics coupled to b quarks

  7. Vertex operators and Jordan fields

    International Nuclear Information System (INIS)

    Ferreira, L.A.; Gomes, J.F.; Zimerman, A.H.

    1988-01-01

    The construction of Lie algebras in terms of Jordan algebras generators is discussed. The key to the construction is the triality relation already incorporated into matrix products. A generalisation to Kac-Moody algebras in terms of vertex operators is proposed and may provide a clue for the construction of new representations of Kac-Moody algebras in terms of Jordan fields. (author) [pt

  8. A Novel Vertex Affinity for Community Detection

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Andy [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sanders, Geoffrey [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Henson, Van [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Vassilevski, Panayot [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-05

    We propose a novel vertex affinity measure in this paper. The new vertex affinity quantifies the proximity between two vertices in terms of their clustering strength and is ideal for such graph analytics applications as community detection. We also developed a framework that combines simple graph searches and resistance circuit formulas to compute the vertex affinity efficiently. We study the properties of the new affinity measure empirically in comparison to those of other popular vertex proximity metrics. Our results show that the existing metrics are ill-suited for community detection due to their lack of fundamental properties that are essential for correctly capturing inter- and intra-cluster vertex proximity.

  9. A nonperturbative fermion-boson vertex

    International Nuclear Information System (INIS)

    Bashir, A.; Raya, A.

    2002-01-01

    We calculate the massive fermion propagator at one-loop order in QED3. The Ward-Takahashi identity (WTI) relates the propagator to the vertex. This allows us to split the vertex into its longitudinal and transverse parts. The former is fixed by the WTI. Following the scheme of Ball and Chiu later modified by Kizilersue et. al., we calculate the full vertex at one-loop order. A mere subtraction of the longitudinal part of the vertex gives us the transverse part. The α dependence in the transverse vertex can be eliminated by making use of the perturbative expressions for the wavefunction renormalization function and the mass function of complicated arguments of the incoming and outgoing fermion momenta. This leads us to a vertex which is nonperturbative in nature. We also calculate an effective vertex for which the arguments of the unknown functions have no angular dependence, making it particularly suitable for numerical studies of dynamical symmetry breaking

  10. Belle II silicon vertex detector

    Energy Technology Data Exchange (ETDEWEB)

    Adamczyk, K. [H. Niewodniczanski Institute of Nuclear Physics, Krakow 31-342 (Poland); Aihara, H. [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan); Angelini, C. [Dipartimento di Fisica, Università di Pisa, I-56127 Pisa (Italy); INFN Sezione di Pisa, I-56127 Pisa (Italy); Aziz, T.; Babu, V. [Tata Institute of Fundamental Research, Mumbai 400005 (India); Bacher, S. [H. Niewodniczanski Institute of Nuclear Physics, Krakow 31-342 (Poland); Bahinipati, S. [Indian Institute of Technology Bhubaneswar, Satya Nagar (India); Barberio, E.; Baroncelli, Ti.; Baroncelli, To. [School of Physics, University of Melbourne, Melbourne, Victoria 3010 (Australia); Basith, A.K. [Indian Institute of Technology Madras, Chennai 600036 (India); Batignani, G. [Dipartimento di Fisica, Università di Pisa, I-56127 Pisa (Italy); INFN Sezione di Pisa, I-56127 Pisa (Italy); Bauer, A. [Institute of High Energy Physics, Austrian Academy of Sciences, 1050 Vienna (Austria); Behera, P.K. [Indian Institute of Technology Madras, Chennai 600036 (India); Bergauer, T. [Institute of High Energy Physics, Austrian Academy of Sciences, 1050 Vienna (Austria); Bettarini, S. [Dipartimento di Fisica, Università di Pisa, I-56127 Pisa (Italy); INFN Sezione di Pisa, I-56127 Pisa (Italy); Bhuyan, B. [Indian Institute of Technology Guwahati, Assam 781039 (India); Bilka, T. [Faculty of Mathematics and Physics, Charles University, 121 16 Prague (Czech Republic); Bosi, F. [INFN Sezione di Pisa, I-56127 Pisa (Italy); Bosisio, L. [Dipartimento di Fisica, Università di Trieste, I-34127 Trieste (Italy); INFN Sezione di Trieste, I-34127 Trieste (Italy); and others

    2016-09-21

    The Belle II experiment at the SuperKEKB collider in Japan is designed to indirectly probe new physics using approximately 50 times the data recorded by its predecessor. An accurate determination of the decay-point position of subatomic particles such as beauty and charm hadrons as well as a precise measurement of low-momentum charged particles will play a key role in this pursuit. These will be accomplished by an inner tracking device comprising two layers of pixelated silicon detector and four layers of silicon vertex detector based on double-sided microstrip sensors. We describe herein the design, prototyping and construction efforts of the Belle-II silicon vertex detector.

  11. The OPAL vertex drift chamber

    International Nuclear Information System (INIS)

    Carter, J.R.; Elcombe, P.A.; Hill, J.C.; Roach, C.M.; Armitage, J.C.; Carnegie, R.K.; Estabrooks, P.; Hemingway, R.; Karlen, D.; McPherson, A.; Pinfold, J.; Roney, J.M.; Routenburg, P.; Waterhouse, J.; Hargrove, C.K.; Klem, D.; Oakham, F.G.; Carter, A.A.; Jones, R.W.L.; Lasota, M.M.B.; Lloyd, S.L.; Pritchard, T.W.; Wyatt, T.R.

    1990-01-01

    A high precision vertex drift chamber has been installed in the OPAL experiment at LEP. The design of the chamber and the associated readout electronics is described. The performance of the system has been studied using cosmic ray muons and the results of these studies are presented. A space resolution of 50 μm in the drift direction is obtained using the OPAL central detector gas mixture at 4 bar. (orig.)

  12. Lectures on the Topological Vertex

    CERN Document Server

    Mariño, M

    2008-01-01

    In this lectures, I will summarize the approach to Gromov–Witten invariants on toric Calabi–Yau threefolds based on large N dualities. Since the large N duality/topological vertex approach computes Gromov–Witten invariants in terms of Chern–Simons knot and link invariants, Sect. 2 is devoted to a review of these. Section 3 reviews topological strings and Gromov–Witten invariants, and gives some information about the open string case. Section 4 introduces the class of geometries we will deal with, namely toric (noncompact) Calabi–Yau manifolds, and we present a useful graphical way to represent these manifolds which constitutes the geometric core of the theory of the topological vertex. Finally, in Sect. 5, we define the vertex and present some explicit formulae for it and some simple applications. A brief Appendix contains useful information about symmetric polynomials. It has not been possible to present all the relevant background and physical derivations in this set of lectures. However, these...

  13. Investigation of ADAMO performance in the ZEUS calorimeter reconstruction program

    International Nuclear Information System (INIS)

    Kowalski, H.; Poser, T.; Stanco, L.; Tscheslog, E.

    1989-01-01

    The ADAMO package has been investigated for the reconstruction of jets simulated in the ZEUS calorimeter. The feasibility of ADAMO routines was tested under various aspects. The study was based on different versions of a cluster algorithm using ADAMO tools or direct BOS memory management tools. In particular, the amount of CPU time needed by each of the versions was determined. Results are quite promising and support an extensive use of the ADAMO package in the software development of high energy physics experiments. (orig.)

  14. Hard photoproduction: An analysis of the first ZEUS data

    International Nuclear Information System (INIS)

    Feld, L.W.

    1993-10-01

    The electron-proton storage ring HERA gives the unique opportunity to study photon-proton collisions at center of mass energies around 200 GeV. This analysis covers the extraction of hard photoproduction events from the data taken by the ZEUS-detector in its first year of operation. It is shown, that these events are well described by the Monte Carlo generators PYTHIA and HERWIG. A jet analysis allows to measure the kinematics of the hard subprocess. Clear evidence for both direct and resolved photon processes is seen in the data. In detailed Monte Carlo studies different photon structure functions are compared to the data. (orig.)

  15. Neural network based electron identification in the ZEUS calorimeter

    International Nuclear Information System (INIS)

    Abramowicz, H.; Caldwell, A.; Sinkus, R.

    1995-01-01

    We present an electron identification algorithm based on a neural network approach applied to the ZEUS uranium calorimeter. The study is motivated by the need to select deep inelastic, neutral current, electron proton interactions characterized by the presence of a scattered electron in the final state. The performance of the algorithm is compared to an electron identification method based on a classical probabilistic approach. By means of a principle component analysis the improvement in the performance is traced back to the number of variables used in the neural network approach. (orig.)

  16. The silicon vertex locator for the LHCb upgrade

    CERN Document Server

    Head, Tim

    2014-01-01

    The upgrade of the LHCb experiment, planned for 2018, will transform the entire readout to a triggerless system being read out at 40 MHz. The upgraded silicon vertex detector (VELO) must be light weight, radiation hard, and compatible with LHC vacuum requirements. It must be capable of fast pattern recognition, fast track reconstruction and high precision vertexing. This challenge is being met with a new VELO design based on hybrid pixel detectors positioned to within 5 mm of the LHC colliding beams. The detector will be shielded from the beam by a View the MathML source~300μm thick aluminium foil. Evaporative CO2 coolant circulating in micro-channels embedded in a thin silicon substrate will be used for cooling.

  17. Energy-loss measurement with the ZEUS Central Tracking Detector

    Energy Technology Data Exchange (ETDEWEB)

    Bartsch, D.

    2007-05-15

    The measurement of the specific energy loss due to ionisation, dE/dx, in a drift chamber is a very important tool for particle identification in final states of reactions between high energetic particles. Such identification requires a well understood dE/dx measurement including a precise knowledge of its uncertainties. Exploiting for the first time the full set of ZEUS data from the HERA operation between 1996 and 2005 twelve detector-related influences affecting the dE/dx measurement of the ZEUS Central Tracking Detector have been identified, separately studied and parameterised. A sophisticated iterative procedure has been developed to correct for these twelve effects, which takes into account the correlations between them. A universal parameterisation of the detector-specific Bethe-Bloch curve valid for all particle species has been extracted. In addition, the various contributions to the measurement uncertainty have been disentangled and determined. This yields the best achievable prediction for the single-track dE/dx resolution. For both the analysis of the measured data and the simulation of detector performance, the detailed understanding of the measurement and resolution of dE/dx gained in this work provides a tool with optimum power for particle identification in a physics studies. (orig.)

  18. Energy-loss measurement with the ZEUS Central Tracking Detector

    International Nuclear Information System (INIS)

    Bartsch, D.

    2007-05-01

    The measurement of the specific energy loss due to ionisation, dE/dx, in a drift chamber is a very important tool for particle identification in final states of reactions between high energetic particles. Such identification requires a well understood dE/dx measurement including a precise knowledge of its uncertainties. Exploiting for the first time the full set of ZEUS data from the HERA operation between 1996 and 2005 twelve detector-related influences affecting the dE/dx measurement of the ZEUS Central Tracking Detector have been identified, separately studied and parameterised. A sophisticated iterative procedure has been developed to correct for these twelve effects, which takes into account the correlations between them. A universal parameterisation of the detector-specific Bethe-Bloch curve valid for all particle species has been extracted. In addition, the various contributions to the measurement uncertainty have been disentangled and determined. This yields the best achievable prediction for the single-track dE/dx resolution. For both the analysis of the measured data and the simulation of detector performance, the detailed understanding of the measurement and resolution of dE/dx gained in this work provides a tool with optimum power for particle identification in a physics studies. (orig.)

  19. String bits and the spin vertex

    OpenAIRE

    Jiang, YunfengInstitut de Physique Théorique, DSM, CEA, URA2306 CNRS Saclay, F-91191 Gif-sur-Yvette, France; Kostov, Ivan(Institut de Physique Théorique, DSM, CEA, URA2306 CNRS Saclay, F-91191 Gif-sur-Yvette, France); Petrovskii, Andrei(Institut de Physique Théorique, DSM, CEA, URA2306 CNRS Saclay, F-91191 Gif-sur-Yvette, France); Serban, Didina(Institut de Physique Théorique, DSM, CEA, URA2306 CNRS Saclay, F-91191 Gif-sur-Yvette, France)

    2015-01-01

    We initiate a novel formalism for computing correlation functions of trace operators in the planar N=4 SYM theory. The central object in our formalism is the spin vertex, which is the weak coupling analogy of the string vertex in string field theory. We construct the spin vertex explicitly for all sectors at the leading order using a set of bosonic and fermionic oscillators. We prove that the vertex has trivial monodromy, or put in other words, it is a Yangian invariant. Since the monodromy o...

  20. The OPAL vertex detector prototype

    International Nuclear Information System (INIS)

    Roney, J.M.; Armitage, J.C.; Carnegie, R.K.; Giles, G.L.; Hemingway, R.J.; McPherson, A.C.; Pinfold, J.L.; Waterhouse, J.; Godfrey, L.; Hargrove, C.K.

    1989-01-01

    The prototype test results of a high resolution charged particle tracking detector are reported. The detector is designed to measure vertex topologies of particles produced in the e + e - collisions of the OPAL experiment at LEP. The OPAL vertex detector is a 1 m long, 0.46 m diameter cylindrical drift chamber consisting of an axial and stereo layer each of which is divided into 36 jet cells. A prototype chamber containing four axial and two stereo cells was studied using a pion test beam at CERN. The studies examined the prototype under a variety of operating conditions. An r-Φ resolution of 60 μm was obtained when the chamber was operated with argon (50%)-ethane (50%) at 3.75 bar, and when CO 2 (80%)-isobutane (20%) at 2.5 bar was used a 25 μm resolution was achieved. A z measurement using end-to-end time difference has a resolution of 3.5 cm. The details of these prototype studies are discussed in this paper. (orig.)

  1. CCD-based vertex detectors

    CERN Document Server

    Damerell, C J S

    2005-01-01

    Over the past 20 years, CCD-based vertex detectors have been used to construct some of the most precise 'tracking microscopes' in particle physics. They were initially used by the ACCMOR collaboration for fixed target experiments in CERN, where they enabled the lifetimes of some of the shortest-lived charm particles to be measured precisely. The migration to collider experiments was accomplished in the SLD experiment, where the original 120 Mpixel detector was later upgraded to one with 307 Mpixels. This detector was used in a range of physics studies which exceeded the capability of the LEP detectors, including the most precise limit to date on the Bs mixing parameter. This success, and the high background hit densities that will inevitably be encountered at the future TeV-scale linear collider, have established the need for a silicon pixel-based vertex detector at this machine. The technical options have now been broadened to include a wide range of possible silicon imaging technologies as well as CCDs (mon...

  2. Status and prospects of the LHCb Vertex Locator

    CERN Document Server

    van Beuzekom, Martin

    2007-01-01

    The Vertex Locator of the LHCb experiment is a dedicated subdetector for the reconstruction of primary and secondary vertices in b-hadron decays. The vertex detector features two halves with 21 modules each, mounted on retractable bases. Each module consists of two half-disk silicon micro-strip sensors measuring hits in R and $\\Phi$ coordinates. The strip pitch ranges from 40 to about 100 $\\mu$m. A vacuum boy with a 300 $\\mu$m thick aluminium foil shields the sensors from the wakefields of the proton beams which are passing at a distance of 8 mm from the active area of the sensors. Because of the harsh non-uniform radiation environment we opted for n-on-n strips in diffusion oxygenated float zone silicon. The current status of the vertex detector, which has recently entered the commissioning phase, will be discussed. Given the limited lifetime of the detector due to the radiation environment, developments for a detector replacement with n-on-p type modules have already started. Possible upgrade scenarios fo...

  3. Dijets in diffractive photoproduction measured with the ZEUS experiment

    International Nuclear Information System (INIS)

    Renner, R.

    2006-10-01

    The diffractive photoproduction of dijets in electron-proton scattering has been studied using 77.1 pb -1 of data taken with the ZEUS detector at HERA. The measurements have been made at a centre-of- mass energy √s=318 GeV in the kinematic range 0.2 P P is the fraction of the proton momentum taken by the diffractive exchange. The jets have been reconstructed using the k T algorithm. The two jets with the highest transversal energy have been required to satisfy E T >7.5 and 6.5 GeV, respectively, and to be in the pseudorapidity range -1.5<η<1.5. Differential cross sections have been measured and been confronted with the predictions from leading order Monte Carlo simulations and next-to-leading order QCD calculations. (orig.)

  4. The ZEUS uranium-scintillator calorimeter for HERA

    International Nuclear Information System (INIS)

    Hilger, E.

    1987-01-01

    The high resolution calorimeter for the ZEUS detector at HERA is presented. The choice of a sandwich calorimeter from depleted uranium plates and plastic scintillator was made to accomplish compensation and thus the best possible energy resolution for hadrons and jets. The calorimeter is segmented transversely into towers and longitudinally into an electromagnetic and one or two hadronic sections. It is divided in a forward, barrel and rear part which surround hermetically the interaction region and the inner detectors. The expected energy resolutions are for electrons σ(E)/E = 0.15/√E, and for hadrons σ(E)/E = 0.35/√E, with a constant term of maximum 2% added in quadrature. First results from calorimeter test measurements are presented. (orig.)

  5. New vertex reconstruction algorithms for CMS

    CERN Document Server

    Frühwirth, R; Prokofiev, Kirill; Speer, T.; Vanlaer, P.; Chabanat, E.; Estre, N.

    2003-01-01

    The reconstruction of interaction vertices can be decomposed into a pattern recognition problem (``vertex finding'') and a statistical problem (``vertex fitting''). We briefly review classical methods. We introduce novel approaches and motivate them in the framework of high-luminosity experiments like at the LHC. We then show comparisons with the classical methods in relevant physics channels

  6. Vertex Reconstruction in ATLAS Run II

    CERN Document Server

    Zhang, Matt; The ATLAS collaboration

    2016-01-01

    Vertex reconstruction is the process of taking reconstructed tracks and using them to determine the locations of proton collisions. In this poster we present the performance of our current vertex reconstruction algorithm, and look at investigations into potential improvements from a new seed finding method.

  7. Verification of the first measurement data of the ZEUS detector

    International Nuclear Information System (INIS)

    Bender, M.

    1992-12-01

    At the begin of this work an extension of the data-analysis program of ZEUS was performed, which simplifies essentially the operation of this program. By this it is now possible to access the measurement data without requirement on knowledge, on which tape they are. On time of the beginning of the data taking a monitoring program was established, which montors continuously the technical function of all components of the ZEUS detector and the data quality. In the framework of this thesis the routine for the control of the central calorimeter was developed. This routine makes a series of histograms available, which both permit the monitoring of each single channel and present global properties of the calorimeter. For each single channel for instance the mean energy and the mean time and their standard deviations are plotted, for the whhole calorimeter among others the energy distribution and the transverse energy are determined. By means of these data failures can be recognized and localized, which escape the local controls. Beyond the comparison over larger time spans is possible. The suppression of background is an essential problem at storage rings, therefore the different background sources are simulated by means of Monte-Carlo generators and from the so obtained results strategies for the reduction of the background developed. By means of the histograms the simulated data were compared with the first measurement results. Thereby no agreement of the simulated beam-residual gas reactions with the measured data could be found. The simulation yields too few events with low energy deposition (up to several GeV) in the calorimeter, but predicts a high-energetic contribution in the energy distributions, which was not measured. (orig.) [de

  8. Proposal for a CLEO precision vertex detector

    International Nuclear Information System (INIS)

    1991-01-01

    Fermilab experiment E691 and CERN experiment NA32 have demonstrated the enormous power of precision vertexing for studying heavy quark physics. Nearly all collider experiments now have or are installing precision vertex detectors. This is a proposal for a precision vertex detector for CLEO, which will be the pre-eminent heavy quark experiment for at least the next 5 years. The purpose of a precision vertex detector for CLEO is to enhance the capabilities for isolating B, charm, and tau decays and to make it possible to measure the decay time. The precision vertex detector will also significantly improve strange particle identification and help with the tracking. The installation and use of this detector at CLEO is an important step in developing a vertex detector for an asymmetric B factory and therefore in observing CP violation in B decays. The CLEO environment imposes a number of unique conditions and challenges. The machine will be operating near the γ (4S) in energy. This means that B's are produced with a very small velocity and travel a distance about 1/2 that of the expected vertex position resolution. As a consequence B decay time information will not be useful for most physics. On the other hand, the charm products of B decays have a higher velocity. For the long lived D + in particular, vertex information can be used to isolate the charm particle on an event-by-event basis. This helps significantly in reconstructing B's. The vertex resolution for D's from B's is limited by multiple Coulomb scattering of the necessarily rather low momentum tracks. As a consequence it is essential to minimize the material, as measured in radiation lengths, in the beam pip and the vertex detector itself. It is also essential to build the beam pipe and detector with the smallest possible radius

  9. A gas monitoring facility with a quadrupole mass spectrometer for the ZEUS transition-radiation chambers

    International Nuclear Information System (INIS)

    Kapp, U.

    1988-07-01

    A gas analysis facility for the ZEUS transition-radiation chambers based on a quadrupole mass spectrometer is described. After a description of the spectrometer, the vacuum system, and the software, some test results are presented. (HSI)

  10. The BELLE silicon vertex detector

    Energy Technology Data Exchange (ETDEWEB)

    Alimonti, G.; Aihara, H.; Alexander, J.; Asano, Y.; Bakich, A.; Bozek, A.; Banas, E.; Browder, T.; Dragic, J.; Fukunaga, C.; Gordon, A.; Guler, H.; Everton, C.; Heenan, E.; Haba, J.; Hazumi, M.; Hastings, N.; Hara, T.; Hojo, T.; Higuchi, T.; Iwai, G.; Ishino, H.; Jalocha, P.; Korotuschenko, K.; Kaneko, J.; Kapusta, P.; Kawasaki, T.; Lange, J.S.; Li, Y.; Marlow, D.; Moloney, G.; Moffitt, L.; Mori, S.; Matsubara, T.; Nakadaira, T.; Nakamura, T.; Natkaniec, Z.; Okuno, S.; Olsen, S.; Ostrowicz, W.; Palka, H.; Peak, L.S.; Ryuko, J.; Rozanska, M.; Sevior, M.; Shimada, J.; Sumisawa, K.; Stock, R.; Stanic, S.; Swain, S.; Taylor, G.; Takasaki, F.; Tajima, H.; Trabelsi, K.; Tamura, N.; Tanaka, J.; Tanaka, M. E-mail: tanakam@post.kek.jp; Takahashi, S.; Tomura, T.; Tsuboyama, T.; Tsujita, Y.; Varner, G.; Varvell, K.E.; Watanabe, Y.; Yamamoto, H.; Yamada, Y.; Yokoyama, M.; Zhao, H.; Zontar, D

    2000-10-11

    A silicon vertex detector has been developed for the BELLE experiment at the KEK B-factory to be used to determine the relative displacements of B-meson decay vertices for CP violation measurements. The device has been successfully installed and operated with high-luminosity beam conditions. The average strip yield is larger than 96%, including the preamplifier electronics yield and the detector is currently working stably with a signal-to-noise ratio of 17-40. The measured impact parameter resolution agrees with expectations based on Monte Carlo simulations, and the measured D{sup 0} lifetime is in good agreement with the particle data group's average of other measurements. Several B{yields}J/{psi}K events produced at the {upsilon}(4S) resonance have been detected and separate decay vertices have been found.

  11. The presampler for the forward and rear calorimeter in the ZEUS detector

    Energy Technology Data Exchange (ETDEWEB)

    Bamberger, A; Bornheim, A; Crittenden, J; Grabosch, H -J; Grothe, M; Hervas, L; Hilger, E; Holm, U; Horstmann, D; Kaufmann, V; Kharchilava, A; Koetz, U; Kummerow, D; Mallik, U; Meyer, A; Nowoczyn, M; Ossowski, R; Schlenstedt, S; Tiecke, H; Verkerke, W; Vossebeld, J; Vreeswijk, M; Wang, S M; Wu, J [Bonn Univ. (Germany). Phys. Inst.; [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); [DESY-IfH Zeuthen, Zeuthen (Germany); [Fakultaet fuer Physik der Universitaet Freiburg, Freiburg i.Br. (Germany); [Hamburg University, I. Institute of Exp. Physics, Hamburg (Germany); [University of Iowa Physics and Astronomy Dept, Iowa City (United States); [Univer. Autonoma Madrid, Depto de Fisica Teorica, Madrid (Spain); [NIKHEF and University of Amsterdam, Amsterdam (Netherlands)

    1996-11-21

    The ZEUS detector at HERA has been supplemented with a presampler detector in front of the forward and rear calorimeters. It consists of a segmented scintillator array read out with wavelength-shifting fibers. We discuss its design, construction and performance. Test beam data obtained with a prototype presampler and the ZEUS prototype calorimeter demonstrate the main function of this detector, i.e. the correction for the energy lost by an electron interacting in inactive material in front of the calorimeter. (orig.).

  12. Vertex operators for a bosonic string

    International Nuclear Information System (INIS)

    Sasaki, Ryu; Yamanaka, Itaru.

    1985-09-01

    Based on the operator formalism and the Virasoro algebra, we present a simple method of constructing vertex operators describing the emission and absorption of general particles in bosonic string theories. (author)

  13. The BaBar silicon vertex tracker

    International Nuclear Information System (INIS)

    Bozzi, C.; Carassiti, V.; Ramusino, A. Cotta; Dittongo, S.; Folegani, M.; Piemontese, L.; Abbott, B.K.; Breon, A.B.; Clark, A.R.; Dow, S.; Fan, Q.; Goozen, F.; Hernikl, C.; Karcher, A.; Kerth, L.T.; Kipnis, I.; Kluth, S.; Lynch, G.; Levi, M.; Luft, P.; Luo, L.; Nyman, M.; Pedrali-Noy, M.; Roe, N.A.; Zizka, G.; Roberts, D.; Barni, D.; Brenna, E.; Defendi, I.; Forti, A.; Giugni, D.; Lanni, F.; Palombo, F.; Vaniev, V.; Leona, A.; Mandelli, E.; Manfredi, P.F.; Perazzo, A.; Re, V.; Angelini, C.; Batignani, G.; Bettarini, S.; Bondioli, M.; Bosi, F.; Calderini, G.; Carpinelli, M.; Dutra, F.; Forti, F.; Gagliardi, D.; Giorgi, M.A.; Lusiani, A.; Mammini, P.; Morganti, M.; Morsani, F.; Paoloni, E.; Profeti, A.; Rama, M.; Rampino, G.; Rizzo, G.; Sandrelli, F.; Simi, G.; Triggiani, G.; Tritto, S.; Vitale, R.; Burchat, P.; Cheng, C.; Kirkby, D.; Meyer, T.; Roat, C.; Bona, M.; Bianchi, F.; Daudo, F.; Girolamo, B. Di; Gamba, D.; Giraudo, G.; Grosso, P.; Romero, A.; Smol, A.; Trapani, P.; Zanin, D.; Bosisio, L.; Ricca, G. Della; Lanceri, L.; Pompili, A.; Poropat, P.; Prest, M.; Rastelli, C.; Vallazza, E.; Vuagnin, G.; Hast, C.; Potter, E.P.; Sharma, V.; Burke, S.; Callahan, D.; Campagnari, C.; Dahmes, B.; Eppich, A.; Hale, D.; Hall, K.; Hart, P.; Kuznetsova, N.; Kyre, S.; Levy, S.; Long, O.; May, J.; Richman, J.; Verkerke, W.; Witherell, M.; Beringer, J.; Eisner, A.M.; Frey, A.; Grillo, A.; Grothe, M.; Johnson, R.; Kroeger, W.; Lockman, W.; Pulliam, T.; Rowe, W.; Schmitz, R.; Seiden, A.; Spencer, E.; Turri, M.; Wilder, M.; Charles, E.; Elmer, P.; Nielsen, J.; Orejudos, W.; Scott, I.; Walsh, J.; Zobernig, H.

    2000-01-01

    The BaBar Silicon Vertex Tracker (SVT) is designed to provide the high-precision vertexing necessary for making measurements of CP violation at the SLAC B-Factory PEP-II. The instrument consists of five layers of double-sided silicon strip detectors and has been installed in the BaBar experiment and taking colliding beam data since May 1999. An overview of the design as well as performance and experience from the initial running will be presented

  14. Design, construction and beam tests of the high resolution uranium scintillator calorimeter for ZEUS

    International Nuclear Information System (INIS)

    Straver, J.A.

    1991-01-01

    HERA will collide protons and electrons with energies up to 820 GeV and 30 GeV respectively. Therefore it allows measurements at momentum transfers (Q) which greatly surpass the investigations carried out so far. This extended range in Q will allow investigation of the interactions between the quarks and leptons at a distance scale of the order of 10 -18 cm. Two detectors are foreseen at HERA H1 and ZEUS. The design of the ZEUS detector is optimized for the study of neutral and charged current interactions. A calorimeter is a detector which absorbs the total incident energy of a particle while generating a signal proportional to this energy. The ZEUS calorimeter is built of alternating layers of dense absorber plates ( 238 U) and active layers of scintillator material with a fast readout system via wavelength shifters, light guides and photomultiplyers. The main subject of this thesis is the description of this calorimeter and its performance. After a short introduction to HERA and the physics topics, the importance of the quality of a calorimeter is pointed out and a brief overview of the ZEUS detector is given. In ch. 3 the principles of high resolution hadron calorimetry and the studies which led to the design of the ZEUS-calorimeter are discussed. Ch. 4 describes the mechanical design of the ZEUS forward calorimeter, the mechanical finite element calculations, and the production of the calorimeter modules at NIKHEF. Finally ch. 6 and 5 show the results of beam tests of the ZEUS forward calorimeter prototypes and the final full size forward calorimeter modules. (author). 59 refs.; 115 figs.; 29 tabs

  15. Neutral strangeness production with the ZEUS detector at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Liu Chuanlei

    2007-12-15

    The inclusive production of the neutral strange particles, {lambda}, anti {lambda} and K{sup 0}{sub S} has been studied with the ZEUS detector at HERA. The measurement provides a way to understand the fragmentation process in ep collisions and to check the universality of this process. The strangeness cross sections have been measured and compared with Monte Carlo (MC) predictions. Over the kinematic regions of interest, no {lambda} to anti {lambda} asymmetry was observed. The relative yield of {lambda} and K{sup 0}{sub S} was determined and the result was compared with MC calculations and results from other experiments. A good agreement was found except for the enhancement in the photoproduction process. Clear rapidity correlation was observed for particle pairs where either quark flavor or baryon number compensation occurs. The K{sup 0}{sub S}K{sup 0}{sub S} Bose-Einstein correlation measurement gives a result consistent with those from LEP measurements. The {lambda} polarizations were measured to be consistent with zero for HERA I data. (orig.)

  16. Development of the calorimeter trigger for the ZEUS detector

    International Nuclear Information System (INIS)

    Smith, W.H.

    1988-01-01

    The purpose of this research was to begin development of the trigger for the calorimeter of the ZEUS detector at HERA, a new storage ring that will provide collisions between 820 GeV protons and 30 GeV electrons by 1990. The calorimeter will be made of depleted uranium plates and plastic scintillator read out by wavelength shifter bars into 12,000 photomultiplier tubes. These signals will be combined into 1000 towers with separate electromagnetic and hadronic sums. The calorimeter first level trigger will be pipelined with a decision provided 5 μsec after each beam crossing, occurring every 96 nsec. The trigger will need to determine the total energy, the total transverse energy, the missing energy, and the energy and number of jets and isolated electrons. The trigger rate needs to be held to 1 kHz against a rate of proton-beam gas interactions of 200 kHz. The summed pulseheights will be digitized by 8-bit flash ADC's. They will be linearized, stored and manipulated digitally. The various pipelined sums will be made using ECL and CMOS technology.This grant was used to investigate these technologies, model the trigger performance, and begin the design. This research will be continued by this principal investigator under another DOE grant at the University of Wisconsin

  17. First level trigger processor for the ZEUS calorimeter

    International Nuclear Information System (INIS)

    Dawson, J.W.; Talaga, R.L.; Burr, G.W.; Laird, R.J.; Smith, W.; Lackey, J.

    1990-01-01

    This paper discusses the design of the first level trigger processor for the ZEUS calorimeter. This processor accepts data from the 13,000 photomultipliers of the calorimeter which is topologically divided into 16 regions, and after regional preprocessing, performs logical and numerical operations which cross regional boundaries. Because the crossing period at the HERA collider is 96 ns, it is necessary that first-level trigger decisions be made in pipelined hardware. One microsecond is allowed for the processor to perform the required logical and numerical operations, during which time the data from ten crossings would be resident in the processor while being clocked through the pipelined hardware. The circuitry is implemented in 100K ECL, Advanced CMOS discrete devices, and programmable gate arrays, and operates in a VME environment. All tables and registers are written/read from VME, and all diagnostic codes are executed from VME. Preprocessed data flows into the processor at a rate of 5.2GB/s, and processed data flows from the processor to the Global First-Level Trigger at a rate of 700MB/s. The system allows for subsets of the logic to be configured by software and for various important variables to be histogrammed as they flow through the processor. 2 refs., 3 figs

  18. Dijets in diffractive photoproduction measured with the ZEUS experiment

    Energy Technology Data Exchange (ETDEWEB)

    Renner, R.

    2006-10-15

    The diffractive photoproduction of dijets in electron-proton scattering has been studied using 77.1 pb{sup -1} of data taken with the ZEUS detector at HERA. The measurements have been made at a centre-of- mass energy {radical}s=318 GeV in the kinematic range 0.27.5 and 6.5 GeV, respectively, and to be in the pseudorapidity range -1.5<{eta}<1.5. Differential cross sections have been measured and been confronted with the predictions from leading order Monte Carlo simulations and next-to-leading order QCD calculations. (orig.)

  19. First-level trigger processor for the ZEUS calorimeter

    International Nuclear Information System (INIS)

    Dawson, J.W.; Talaga, R.L.; Burr, G.W.; Laird, R.J.; Smith, W.; Lackey, J.

    1990-01-01

    The design of the first-level trigger processor for the Zeus calorimeter is discussed. This processor accepts data from the 13,000 photomultipliers of the calorimeter, which is topologically divided into 16 regions, and after regional preprocessing performs logical and numerical operations that cross regional boundaries. Because the crossing period at the HERA collider is 96 ns, it is necessary that first-level trigger decisions be made in pipelined hardware. One microsecond is allowed for the processor to perform the required logical and numerical operations, during which time the data from ten crossings would be resident in the processor while being clocked through the pipelined hardware. The circuitry is implemented in 100K emitter-coupled logic (ECL), advanced CMOS discrete devices and programmable gate arrays, and operates in a VME environment. All tables and registers are written/read from VME, and all diagnostic codes are executed from VME. Preprocessed data flows into the processor at a rate of 5.2 Gbyte/s, and processed data flows from the processor to the global first-level trigger at a rate of 70 Mbyte/s. The system allows for subsets of the logic to be configured by software and for various important variables to be histogrammed as they flow through the processor

  20. Prototype VME data acquisition card for the ZEUS calorimeter

    International Nuclear Information System (INIS)

    Dawson, J.W.; Berg, J.S.; Schlereth, J.L.; Stanek, R.

    1988-01-01

    This paper discusses the design of a prototype data acquisition (DAQ) card for the ZEUS calorimeter. The card accepts two multiplexes analog data streams at a 1 MHz rate, and digitizes and stores the data for subsequent transfer through VME to a host computer. The data is buffered by a high-speed asynchronous FIFO following the A/D converters, and written into Data Memory on the card, either directly or after processing by an on-board digital signal processor (DSP). Each card has a 16-bit control-status register (CSR), the bits of which configure the hardware and define the hardware options. The 1/4 Mbyte of high speed CMOS static RAM appears either as a FIFO, or mapped memory depending upon a bit in the CSR. The card is designed to make use of the 32-bit data and address buses supported by VME, and accordingly can be most efficiently utilized in conjunction with a processor in the VME environment such as the 68020, which supports longword transfers in a 32-bit address space. The card is constructed on a ten layer printed circuit, with almost all components being surface-mount devices. All logic is implemented in PLD's. 5 refs., 4 figs., 3 tabs

  1. Diffractive dijet production in deep inelastic scattering at ZEUS

    International Nuclear Information System (INIS)

    Bonato, A.

    2008-03-01

    This thesis presents a measurement of dijet production of diffractive deep inelastic scattering ep collisions. This type of process is specially relevant for the experimental validity of the perturbative QCD approach to diffractive physics. The measurement was based on an integrated luminosity of 61 pb -1 collected at the HERA collider with the ZEUS experiment. The events were selected for virtualities of the photon, γ*, 5 2 2 , and energies of the γ*p centre-of-mass, 100 T algorithm in the γ*p frame. The jets were required to have a transverse energy in the γ*p frame E T jet *>4 GeV. The jet with the highest transverse energy was required to have E T jet *>5 GeV. All jets were required to be in the pseudorapidity range -3.5 jet * P , was required to be x P TOT D (ep→ep jet 1 jet 2 X')=9.15±1.2 (stat.) 5.4 3.3 (syst.) -5.3 +6.4 (corr.)pb. Single and double differential cross sections were extracted and compared to leading-order predictions and next-to-leading-order QCD calculations. The latter used several diffractive parton densities extracted from inclusive diffractive deep inelastic scattering data. The agreement with the leading and next-to-leading order predictions is good and no hints of factorisation breaking are observed. The double differential measurement can be a previous input for the extraction of more accurate diffractive parton densities. (orig.)

  2. The design, status and performance of the ZEUS central tracking detector electronics

    International Nuclear Information System (INIS)

    Foster, B.; Cussans, D.G.; Fawcett, H.F.; Gilmore, R.S.; Heath, G.P.; Llewellyn, T.J.; Malos, J.; Morgado, C.J.S.; Tapper, R.J.; Gingrich, D.M.; Harnew, N.; Hallam-Baker, P.; Nash, J.; Khatri, T.; Shield, P.D.; McArthur, I.; Topp-Jorgensen, S.; Wilson, F.F.; Allen, D.; Baird, S.A.; Carter, R.; Galagadera, S.; Gibson, M.D.; Hatley, R.S.; Jeffs, M.; Milborrow, R.; Morissey, M.; Quinton, S.P.H.; White, D.J.; Lane, J.; Nixon, G.; Postranecky, M.; Jamdagni, A.K.; Marcou, C.; Miller, D.B.; Toudup, L.

    1992-01-01

    The readout system developed for the ZEUS central tracking detector (CTD) is described. The CTD is required to provide an accurate measurement of the sagitta and energy loss of charged particles as well as provide fast trigger information. This must be carried out in the HERA environment in which beams cross every 96 ns. The first two aims are achieved by digitizing chamber pulses using a pipelined 104 MHz FADC system. The trigger uses a fast determination of the difference in the arrival times of a pulse at each end of the CTD. It processes this data and gives information to the ZEUS global first level trigger. The modules are housed in custom-built racks and crates and read out using a DAQ system based on Transputer readout controllers. These also monitor data quality and produce data for the ZEUS second level Trigger. (orig.)

  3. A Preliminary ZEUS Lightning Location Error Analysis Using a Modified Retrieval Theory

    Science.gov (United States)

    Elander, Valjean; Koshak, William; Phanord, Dieudonne

    2004-01-01

    The ZEUS long-range VLF arrival time difference lightning detection network now covers both Europe and Africa, and there are plans for further expansion into the western hemisphere. In order to fully optimize and assess ZEUS lightning location retrieval errors and to determine the best placement of future receivers expected to be added to the network, a software package is being developed jointly between the NASA Marshall Space Flight Center (MSFC) and the University of Nevada Las Vegas (UNLV). The software package, called the ZEUS Error Analysis for Lightning (ZEAL), will be used to obtain global scale lightning location retrieval error maps using both a Monte Carlo approach and chi-squared curvature matrix theory. At the core of ZEAL will be an implementation of an Iterative Oblate (IO) lightning location retrieval method recently developed at MSFC. The IO method will be appropriately modified to account for variable wave propagation speed, and the new retrieval results will be compared with the current ZEUS retrieval algorithm to assess potential improvements. In this preliminary ZEAL work effort, we defined 5000 source locations evenly distributed across the Earth. We then used the existing (as well as potential future ZEUS sites) to simulate arrival time data between source and ZEUS site. A total of 100 sources were considered at each of the 5000 locations, and timing errors were selected from a normal distribution having a mean of 0 seconds and a standard deviation of 20 microseconds. This simulated "noisy" dataset was analyzed using the IO algorithm to estimate source locations. The exact locations were compared with the retrieved locations, and the results are summarized via several color-coded "error maps."

  4. ZEUS contributions to the Real-Time 93 conference, Vancouver, Canada

    International Nuclear Information System (INIS)

    1993-07-01

    This is a collection of the eight contributions of the ZEUS Data Acquisition group, presented at the Eighth Conference on Real-Time Computer Applications in Nuclear, Particle and Plasma Physics, Vancouver, Canada, June 8-11, 1993. This note describes the major parts of the ZEUS Data Acquisition system and the experience gained since the first HERA running in April 1992. Note that the papers are appended in the order of recommended reading, which does not reflect the order of importance. The presenters for the papers are listed in the following. (orig.)

  5. Mathematical framework for fast and rigorous track fit for the ZEUS detector

    Energy Technology Data Exchange (ETDEWEB)

    Spiridonov, Alexander

    2008-12-15

    In this note we present a mathematical framework for a rigorous approach to a common track fit for trackers located in the inner region of the ZEUS detector. The approach makes use of the Kalman filter and offers a rigorous treatment of magnetic field inhomogeneity, multiple scattering and energy loss. We describe mathematical details of the implementation of the Kalman filter technique with a reduced amount of computations for a cylindrical drift chamber, barrel and forward silicon strip detectors and a forward straw drift chamber. Options with homogeneous and inhomogeneous field are discussed. The fitting of tracks in one ZEUS event takes about of 20ms on standard PC. (orig.)

  6. Quantum vertex model for reversible classical computing.

    Science.gov (United States)

    Chamon, C; Mucciolo, E R; Ruckenstein, A E; Yang, Z-C

    2017-05-12

    Mappings of classical computation onto statistical mechanics models have led to remarkable successes in addressing some complex computational problems. However, such mappings display thermodynamic phase transitions that may prevent reaching solution even for easy problems known to be solvable in polynomial time. Here we map universal reversible classical computations onto a planar vertex model that exhibits no bulk classical thermodynamic phase transition, independent of the computational circuit. Within our approach the solution of the computation is encoded in the ground state of the vertex model and its complexity is reflected in the dynamics of the relaxation of the system to its ground state. We use thermal annealing with and without 'learning' to explore typical computational problems. We also construct a mapping of the vertex model into the Chimera architecture of the D-Wave machine, initiating an approach to reversible classical computation based on state-of-the-art implementations of quantum annealing.

  7. A note on arbitrarily vertex decomposable graphs

    Directory of Open Access Journals (Sweden)

    Antoni Marczyk

    2006-01-01

    Full Text Available A graph \\(G\\ of order \\(n\\ is said to be arbitrarily vertex decomposable if for each sequence \\((n_{1},\\ldots,n_k\\ of positive integers such that \\(n_{1}+\\ldots+n_{k}=n\\ there exists a partition \\((V_{1},\\ldots,V_{k}\\ of the vertex set of \\(G\\ such that for each \\(i \\in \\{1,\\ldots,k\\}\\, \\(V_{i}\\ induces a connected subgraph of \\(G\\ on \\(n_i\\ vertices. In this paper we show that if \\(G\\ is a two-connected graph on \\(n\\ vertices with the independence number at most \\(\\lceil n/2\\rceil\\ and such that the degree sum of any pair of non-adjacent vertices is at least \\(n-3\\, then \\(G\\ is arbitrarily vertex decomposable. We present another result for connected graphs satisfying a similar condition, where the bound \\(n-3\\ is replaced by \\(n-2\\.

  8. Secondary vertex detection at the SLC

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    The vertex topology of a high energy e + e - interaction contains a wealth of information. These interactions copiously produce the tau lepton and hadrons containing the c and b quarks; all these particles decay within a millimeter or so of the primary interaction point, giving these interactions a rich secondary vertex structure. With suitable detectors, one can hope to reconstruct these vertices and so tag events with tau's, c's and b's; measure lifetimes and mixing angles; and perhaps directly measure the flavor of c and b jets. The spatial resolution and track-pair resolution required of such detectors demand detector development, but several techniques, including solid state microstrip and CCD detectors, pressurized drift chambers, and holographic bubbble chambers look promising. Vertex detection in the colliding beam environment has already yielded a measurement of the tau lifetime. The SLC, with its micron-sized beam and one-centimeter sized beam pipe is uniquely suited for these studies. Compared to conventional storage rings, it offers a well-defined and minute primary interaction point, the possibility of locating a detector within a centimeter of the interaction (an order of magnitude improvement over LEP), negligibly thin beam pipes, and a repetition rate low enough to permit novel detectors and readout schemes. This report discusses the physics accessible with vertex detectors, depicts the physics environment at 100 GeV - particle multiplicities, momenta, angular correlations, and topologies of charm decays, sketches the elements of a vertex detector, and, through some model studies evaluates the spatial resolution and track-pair resolution requirements, and summarizes the detector technologies which seem most promising for vertex detection

  9. Performance of the LHCb Vertex Locator

    CERN Document Server

    Bjørnstad, Pal Marius

    2011-01-01

    The Vertex Locator is a silicon microstrip detector which provides the LHCb experiment with high precision measurements of tracks and decay vertices. The VELO sensors are exposed to a radiation dose of (2.5-6.5) x 10$^{13}n_{eq}$/cm$^2$ per fb$^{-1}$ in the area which is most irradiated. A best hit resolution of 4$mu$ is obtained for angled tracks, in agreement with expectations. The VELO has a vertex position resolution down to 11$mu$m in the transverse direction and an excellent momentum dependent performance.

  10. Random tree growth by vertex splitting

    International Nuclear Information System (INIS)

    David, F; Dukes, W M B; Jonsson, T; Stefánsson, S Ö

    2009-01-01

    We study a model of growing planar tree graphs where in each time step we separate the tree into two components by splitting a vertex and then connect the two pieces by inserting a new link between the daughter vertices. This model generalizes the preferential attachment model and Ford's α-model for phylogenetic trees. We develop a mean field theory for the vertex degree distribution, prove that the mean field theory is exact in some special cases and check that it agrees with numerical simulations in general. We calculate various correlation functions and show that the intrinsic Hausdorff dimension can vary from 1 to ∞, depending on the parameters of the model

  11. Vertex Reconstruction for AEGIS’ FACT Detector

    CERN Document Server

    Themistokleous, Neofytos

    2017-01-01

    My project dealt with the development of a vertex reconstruction technique to discriminate antihydrogen from background signals in the AEGIS apparatus. It involved the creation of a Toy Monte-Carlo to simulate particle annihilation events, and a vertex reconstruction utility based on the Bayesian theory of probability. The first results based on 107 generated events with single track in the detector are encouraging. For such events, the algorithm can reconstruct the z-coordinate accurately , while for the r-coordinate the result is less accurate.

  12. Primary vertex reconstruction at the ATLAS experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00301388; The ATLAS collaboration; Casper, D.; Hooberman, B.; Gui, B.; Lee, G.; Maurer, J.; Morley, A.; Pagan Griso, S.; Petersen, B.; Prokofiev, K.; Shan, L.; Shope, D.; Wharton, A.; Whitmore, B.; Zhang, M.

    2017-01-01

    These proceedings present the method and performance of primary vertex reconstruction at the ATLAS experiment during Runs 1 and 2 at the LHC. The studies presented focus on data taken during 2012 at a centre-of-mass energy of $\\sqrt{s} = 8$ TeV, and during 2015-2016 at $\\sqrt{s} = 13$ TeV. Some predictions toward future runs are also presented. The measurement of the position and size of the luminous region and its use as a constraint to improve the primary vertex resolution are discussed.

  13. Diffractive dijet production in deep inelastic scattering at ZEUS

    Energy Technology Data Exchange (ETDEWEB)

    Bonato, A.

    2008-03-15

    This thesis presents a measurement of dijet production of diffractive deep inelastic scattering ep collisions. This type of process is specially relevant for the experimental validity of the perturbative QCD approach to diffractive physics. The measurement was based on an integrated luminosity of 61 pb{sup -1} collected at the HERA collider with the ZEUS experiment. The events were selected for virtualities of the photon, {gamma}*, 54 GeV. The jet with the highest transverse energy was required to have E{sub T} {sub jet}*>5 GeV. All jets were required to be in the pseudorapidity range -3.5<{eta}{sub jet}*<0 as measured in the {gamma}*p frame. The selection of diffractive events was carried out by requiring a large rapidity gap in the direction of the scattered proton. The value of the fraction of initial proton momentum entering in the hard process, x{sub P}, was required to be x{sub P}<0.03. The total cross section for the process was measured to be {sigma}{sub TOT}{sup D}(ep{yields}ep jet{sub 1}jet{sub 2} X')=9.15{+-}1.2 (stat.){sub 5.4}{sup 3.3} (syst.){sub -5.3}{sup +6.4} (corr.)pb. Single and double differential cross sections were extracted and compared to leading-order predictions and next-to-leading-order QCD calculations. The latter used several diffractive parton densities extracted from inclusive diffractive deep inelastic scattering data. The agreement with the leading and next-to-leading order predictions is good and no hints of factorisation breaking are observed. The double differential measurement can be a previous input for the extraction of more accurate diffractive parton densities. (orig.)

  14. Improving vertex position determination by using a kinematic fit

    International Nuclear Information System (INIS)

    Forden, G.E.; Saxon, D.H.

    1985-05-01

    A method is developed for improving decay vertex reconstruction by using kinematic fits. This is applied to generated charm meson decays. An improvement of 16% in the vertex position measurement along the flight path is achieved. (author)

  15. Intertwiner dynamics in the flipped vertex

    Energy Technology Data Exchange (ETDEWEB)

    Alesci, Emanuele; Bianchi, Eugenio; Magliaro, Elena; Perini, Claudio, E-mail: alesci@fis.uniroma3.i, E-mail: e.bianchi@sns.i, E-mail: elena.magliaro@gmail.co, E-mail: claude.perin@libero.i [Centre de Physique Theorique de Luminy, Case 907, F-13288 Marseille (France)

    2009-09-21

    We continue the semiclassical analysis, started in a previous paper, of the intertwiner sector of the flipped vertex spinfoam model. We use independently both a semi-analytical and a purely numerical approach, finding the correct behavior of wavepacket propagation and physical expectation values. In the end, we show preliminary results about correlation functions.

  16. Twisted Frobenius Identities from Vertex Operator Superalgebras

    Directory of Open Access Journals (Sweden)

    Alexander Zuevsky

    2017-01-01

    Full Text Available In consideration of the continuous orbifold partition function and a generating function for all n-point correlation functions for the rank two free fermion vertex operator superalgebra on the self-sewing torus, we introduce the twisted version of Frobenius identity.

  17. Twisted Frobenius identies from vertex operator superalgebras

    Czech Academy of Sciences Publication Activity Database

    Zuevsky, Alexander

    2017-01-01

    Roč. 2017, 9 November (2017), č. článku 2340410. ISSN 1687-9120 Institutional support: RVO:67985840 Keywords : vertex operator superalgebras * intertwining operators * Riemann surfaces Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 0.643, year: 2016 https://www.hindawi.com/journals/amp/2017/2340410/

  18. Algebraic characterization of the Witten vertex

    International Nuclear Information System (INIS)

    Embacher, F.

    1989-01-01

    The Witten vertex of open bosonic string field theory is characterized by a set of algebraic properties written down in the Fock-space operator formalism. The typical 3-string overlap structure as well as the correct ghost midpoint insertion are not required from the outset but arise as consequences. 20 refs. (Author)

  19. LHCb Vertex Locator Upgrade Work Report

    CERN Document Server

    Estrada, Michael

    2017-01-01

    As the LHCb prepares for the planned upgrade of its vertex locator, there is a great need for supporting work such as the design and testing of apparatus that will ensure the smooth implementation of new hardware and infrastructure. My work this summer consisted largely of tasks to support this process.

  20. Cluster algebras bases on vertex operator algebras

    Czech Academy of Sciences Publication Activity Database

    Zuevsky, Alexander

    2016-01-01

    Roč. 30, 28-29 (2016), č. článku 1640030. ISSN 0217-9792 Institutional support: RVO:67985840 Keywords : cluster alegbras * vertex operator algebras * Riemann surfaces Subject RIV: BA - General Mathematics Impact factor: 0.736, year: 2016 http://www.worldscientific.com/doi/abs/10.1142/S0217979216400300

  1. Primary Vertex Reconstruction at the ATLAS Experiment

    CERN Document Server

    Grimm, Kathryn; The ATLAS collaboration

    2016-01-01

    Efficient and precise reconstruction of the primary vertex in an LHC collision is essential in both the reconstruction of the full kinematic properties of a hard-scatter event and of soft interactions as a measure of the amount of pile-up. The reconstruction of primary vertices in the busy, high pile-up environment of Run-2 of the LHC is a challenging task. New methods have been developed by the ATLAS experiment to reconstruct vertices in such environments. Advances in vertex seeding include methods taken from medical imaging, which allow for reconstruction of multiple vertices with small spatial separation. The adoption of this new seeding algorithm within the ATLAS adaptive vertex finding and fitting procedure will be discussed, and the first results of the new techniques from Run-2 data will be presented. Additionally, data-driven methods to evaluate vertex resolution will be presented with special focus on correct methods to evaluate the effect of the beam spot constraint; results from these methods in Ru...

  2. Lifetime tests for MAC vertex chamber

    International Nuclear Information System (INIS)

    Nelson, H.N.

    1986-07-01

    A vertex chamber for MAC was proposed to increase precision in the measurement of the B hadron and tau lepton lifetimes. Thin-walled aluminized mylar drift tubes were used for detector elements. A study of radiation hardness was conducted under the conditions of the proposed design using different gases and different operating conditions

  3. Silicon vertex detector for superheavy elements identification

    Directory of Open Access Journals (Sweden)

    Bednarek A.

    2012-07-01

    Full Text Available Silicon vertex detector for superheavy elements (SHE identification has been proposed. It will be constructed using very thin silicon detectors about 5 μm thickness. Results of test of 7.3 μm four inch silicon strip detector (SSD with fission fragments and α particles emitted by 252Cf source are presented

  4. Perturbative quantum field theory via vertex algebras

    International Nuclear Information System (INIS)

    Hollands, Stefan; Olbermann, Heiner

    2009-01-01

    In this paper, we explain how perturbative quantum field theory can be formulated in terms of (a version of) vertex algebras. Our starting point is the Wilson-Zimmermann operator product expansion (OPE). Following ideas of a previous paper (S. Hollands, e-print arXiv:0802.2198), we consider a consistency (essentially associativity) condition satisfied by the coefficients in this expansion. We observe that the information in the OPE coefficients can be repackaged straightforwardly into 'vertex operators' and that the consistency condition then has essentially the same form as the key condition in the theory of vertex algebras. We develop a general theory of perturbations of the algebras that we encounter, similar in nature to the Hochschild cohomology describing the deformation theory of ordinary algebras. The main part of the paper is devoted to the question how one can calculate the perturbations corresponding to a given interaction Lagrangian (such as λφ 4 ) in practice, using the consistency condition and the corresponding nonlinear field equation. We derive graphical rules, which display the vertex operators (i.e., OPE coefficients) in terms of certain multiple series of hypergeometric type.

  5. Project ZEUS: a field irradiator for small-mammal population studies

    International Nuclear Information System (INIS)

    Turner, B.N.; Iverson, S.L.

    1976-08-01

    The ZEUS (Zoological Environment Under Stress) Project will assess the effects of long-term low-level radiation on meadow vole populations in a northern temperate area through a series of replicated experimental irradiations. These rodent populations will live in grassland areas surrounded by forest, and will be exposed to a dose designed to be a maximum 6 R/day. (author)

  6. The data-acquisition and second level trigger system for the ZEUS calorimeter

    International Nuclear Information System (INIS)

    Lugt, H.J. van der.

    1993-01-01

    ZEUS and HERA are introduced in chapter 1 with emphasis on the ZEUS Calorimeter and the ZEUS trigger system. The analog and digital electronics developed for the readout of the Calorimeter signals, and the hardware for the Calorimeter Second Level Trigger and data-acquisition system, is described in chapter 2. Emphasis is put on the hardware developed at NIKHEF, which is based on the transputer as the main processing element. The ZEUS trigger and data-acquisition environment as well as the calibration procedures needed for the Calorimeter impose several requirements on the design of the data-acquisition system. The requirements, their implications for the design of the transputer network architecture and the design itself, are described in detail in chapter 3. The software developed for the Calorimeter data-acquisition is described in chapter 4. It includes both the software for the Calorimeter data-acquisition as that required for the calibration of the Calorimeter. First experiences with the CAL-SLT algorithms, obtained during the 1992 HERA running periods, are presented in chapter 5. Chapter 6 discusses the performance of the Calorimeter data-acquisition system. (orig.)

  7. On fermionic representation of the framed topological vertex

    International Nuclear Information System (INIS)

    Deng, Fusheng; Zhou, Jian

    2015-01-01

    The Gromov-Witten invariants of ℂ"3 with branes is encoded in the topological vertex which has a very complicated combinatorial expression. A simple formula for the topological vertex was proposed by Aganagic et al. in the fermionic picture. We will propose a similar formula for the framed topological vertex and prove it in the case when there are one or two branes.

  8. The vertex Zagreb indices of some graph operations

    Directory of Open Access Journals (Sweden)

    N. De

    2016-12-01

    Full Text Available Recently, Tavakoli et al. introduced a new version of Zagreb indices, named as vertex Zagreb indices. In this paper explicit expressions of different graphs operations of vertex Zagreb indices are presented and also as an application, explicit formulas for vertex Zagreb indices of some chemical graphs are obtained.

  9. Certain extensions of vertex operator algebras of affine type

    International Nuclear Information System (INIS)

    Li Haisheng

    2001-01-01

    We generalize Feigin and Miwa's construction of extended vertex operator (super)algebras A k (sl(2)) for other types of simple Lie algebras. For all the constructed extended vertex operator (super)algebras, irreducible modules are classified, complete reducibility of every module is proved and fusion rules are determined modulo the fusion rules for vertex operator algebras of affine type. (orig.)

  10. Vertex Reconstruction and Performance in ATLAS

    CERN Document Server

    Whitmore, Ben William; The ATLAS collaboration

    2017-01-01

    Efficient and precise reconstruction of the primary vertices in LHC collisions is essential in both the reconstruction of the full kinematic properties of a hard-scatter event and of soft interactions as a measure of the amount of pile-up. The reconstruction of the primary vertices in the busy, high pile up environment of the LHC is a challenging task. The challenges and novel methods developed by the ATLAS experiment to reconstruct vertices in such environments will be presented. The performance of the current vertexing algorithms using Run-2 data will be presented and compared to results from simulation. Additionally, data-driven methods to evaluate vertex resolution, and details of upgrades to the ATLAS inner detector will be presented.

  11. The CDF online silicon vertex tracker

    International Nuclear Information System (INIS)

    Ashmanskas, W.

    2001-01-01

    The CDF Online Silicon Vertex Tracker reconstructs 2-D tracks by linking hit positions measured by the Silicon Vertex Detector to the Central Outer Chamber tracks found by the eXtremely Fast Tracker. The system has been completely built and assembled and it is now being commissioned using the first CDF run II data. The precision measurement of the track impact parameter will allow triggering on B hadron decay vertices and thus investigating important areas in the B sector, like CP violation and B s mixing. In this paper we briefly review the architecture and the tracking algorithms implemented in the SVT and we report on the performance of the system achieved in the early phase of CDF run II

  12. The CDF online Silicon Vertex Tracker

    International Nuclear Information System (INIS)

    Ashmanskas, W.; Bardi, A.; Bari, M.; Belforte, S.; Berryhill, J.; Bogdan, M.; Carosi, R.; Cerri, A.; Chlachidze, G.; Culbertson, R.; Dell'Orso, M.; Donati, S.; Fiori, I.; Frisch, H.J.; Galeotti, S.; Giannetti, P.; Glagolev, V.; Moneta, L.; Morsani, F.; Nakaya, T.; Passuello, D.; Punzi, G.; Rescigno, M.; Ristori, L.; Sanders, H.; Sarkar, S.; Semenov, A.; Shochet, M.; Speer, T.; Spinella, F.; Wu, X.; Yang, U.; Zanello, L.; Zanetti, A.M.

    2002-01-01

    The CDF Online Silicon Vertex Tracker (SVT) reconstructs 2D tracks by linking hit positions measured by the Silicon Vertex Detector to the Central Outer Chamber tracks found by the eXtremely Fast Tracker (XFT). The system has been completely built and assembled and it is now being commissioned using the first CDF run II data. The precision measurement of the track impact parameter will allow triggering on B hadron decay vertices and thus investigating important areas in the B sector, like CP violation and B s mixing. In this paper we briefly review the architecture and the tracking algorithms implemented in the SVT and we report on the performance of the system achieved in the early phase of CDF run II

  13. Silicon technologies for the CLIC vertex detector

    Science.gov (United States)

    Spannagel, S.

    2017-06-01

    CLIC is a proposed linear e+e- collider designed to provide particle collisions at center-of-mass energies of up to 3 TeV. Precise measurements of the properties of the top quark and the Higgs boson, as well as searches for Beyond the Standard Model physics require a highly performant CLIC detector. In particular the vertex detector must provide a single point resolution of only a few micrometers while not exceeding the envisaged material budget of around 0.2% X0 per layer. Beam-beam interactions and beamstrahlung processes impose an additional requirement on the timestamping capabilities of the vertex detector of about 10 ns. These goals can only be met by using novel techniques in the sensor and ASIC design as well as in the detector construction. The R&D program for the CLIC vertex detector explores various technologies in order to meet these demands. The feasibility of planar sensors with a thickness of 50-150 μm, including different active edge designs, are evaluated using Timepix3 ASICs. First prototypes of the CLICpix readout ASIC, implemented in 65 nm CMOS technology and with a pixel size of 25×25μm 2, have been produced and tested in particle beams. An updated version of the ASIC with a larger pixel matrix and improved precision of the time-over-threshold and time-of-arrival measurements has been submitted. Different hybridization concepts have been developed for the interconnection between the sensor and readout ASIC, ranging from small-pitch bump bonding of planar sensors to capacitive coupling of active HV-CMOS sensors. Detector simulations based on Geant 4 and TCAD are compared with experimental results to assess and optimize the performance of the various designs. This contribution gives an overview of the R&D program undertaken for the CLIC vertex detector and presents performance measurements of the prototype detectors currently under investigation.

  14. Primary vertex reconstruction with the ATLAS detector

    International Nuclear Information System (INIS)

    Meloni, F.

    2016-01-01

    Efficient and precise reconstruction of the primary vertex in a LHC collision is essential for determining the full kinematic properties of a hard-scatter event and of soft interactions as a measure of the amount of pile-up. The reconstruction of primary vertices in the busy, high pile-up environment of Run-2 of the LHC is a challenging task. The algorithms developed by the ATLAS experiments to reconstruct multiple vertices with small spatial separation are presented.

  15. The H1 silicon vertex detector

    International Nuclear Information System (INIS)

    Pitzl, D.; Behnke, O.; Biddulph, M.; Boesiger, K.; Eichler, R.; Erdmann, W.; Gabathuler, K.; Gassner, J.; Haynes, W.J..; Horisberger, R.; Kausch, M.; Lindstroem, M.; Niggli, H.; Noyes, G.; Pollet, P.; Steiner, S.; Streuli, S.; Szeker, K.; Truoel, P.

    2000-01-01

    The design, construction and performance of the H1 silicon vertex detector is described. It consists of two cylindrical layers of double-sided, double-metal silicon sensors read out by a custom designed analog pipeline chip. The analog signals are transmitted by optical fibres to a custom-designed ADC board and are reduced on PowerPC processors. Details of the design and construction are given and performance figures from the first data-taking periods are presented

  16. The three-gluon vertex of QCD

    International Nuclear Information System (INIS)

    Koller, K.; Zerwas, P.M.; Walsh, T.F.

    1978-12-01

    We show how the Q 2 evolution of gluon jets can be used to provide indirect but strong evidence for the 3 gluon vertex of QCD. We propose looking for this evolution in the QantiQ → 3G → hadrons decay of successive 1 3 S 1 quarkonium states. The results apply to other processes if G jets can be isolated. (orig.) [de

  17. Nonperturbative Aspects of Axial Vector Vertex

    Institute of Scientific and Technical Information of China (English)

    ZONG Hong-Shi; CHEN Xiang-Song; WANG Fan; CHANG Chao-Hsi; ZHAO En-Guang

    2002-01-01

    It is shown how the axial vector current of current quarks is related to that of constituent quarks within the framework of the global color symmetry model.Gluon dressing of the axial vector vertex and the quark self-energy functions are described by the inhomogeneous Bethe-Salpeter equation in the ladder approximation and the Schwinger Dyson equation in the rainbow approximation,respectively.

  18. Vertical integration technologies for vertex detectors

    International Nuclear Information System (INIS)

    Ratti, L.

    2011-01-01

    This work is focused on the use of vertical integration (3D) technologies in the design of hybrid or monolithic pixel detectors in view of applications to silicon vertex trackers (SVTs) at the future high luminosity colliders. After a short introduction on the specifications of next-generation SVTs, the paper will discuss the general features of 3D microelectronic processes and the benefits they can provide to the design of pixel detectors for high energy physics experiments.

  19. Vertex chamber for the KEDR detector

    International Nuclear Information System (INIS)

    Aulchenko, V.M.; Chilingarov, A.G.; Kolachev, G.M.; Lazarenko, O.B.; Nagaslaev, V.P.; Romanov, L.V.

    1989-01-01

    The project and design of the vertex chamber for the KEDR detector is described. The chamber consists of 6 cylindrical layers of tubes with 10 mm diameter and 800 mm length. The tubes are made of 20 μm thick aluminized mylar. The prototype tests show that it is possible to achieve a resolution of 20-30 μm using the cool gas mixtures. (orig.)

  20. Flipped spinfoam vertex and loop gravity

    Energy Technology Data Exchange (ETDEWEB)

    Engle, Jonathan; Pereira, Roberto [CPT, CNRS Case 907, Universite de la Mediterranee, F-13288 Marseille (France); Rovelli, Carlo [CPT, CNRS Case 907, Universite de la Mediterranee, F-13288 Marseille (France)], E-mail: rovelli@cpt.univ-mrs.fr

    2008-07-21

    We introduce a vertex amplitude for 4d loop quantum gravity. We derive it from a conventional quantization of a Regge discretization of euclidean general relativity. This yields a spinfoam sum that corrects some difficulties of the Barrett-Crane theory. The second class simplicity constraints are imposed weakly, and not strongly as in Barrett-Crane theory. Thanks to a flip in the quantum algebra, the boundary states turn out to match those of SO(3) loop quantum gravity-the two can be identified as eigenstates of the same physical quantities-providing a solution to the problem of connecting the covariant SO(4) spinfoam formalism with the canonical SO(3) spin-network one. The vertex amplitude is SO(3) and SO(4)-covariant. It rectifies the triviality of the intertwiner dependence of the Barrett-Crane vertex, which is responsible for its failure to yield the correct propagator tensorial structure. The construction provides also an independent derivation of the kinematics of loop quantum gravity and of the result that geometry is quantized.

  1. Silicon Technologies for the CLIC Vertex Detector

    CERN Document Server

    Spannagel, Simon

    2017-01-01

    CLIC is a proposed linear e$^+$e$^−$ collider designed to provide particle collisions at center-of-mass energies of up to 3 TeV. Precise measurements of the properties of the top quark and the Higgs boson, as well as searches for Beyond the Standard Model physics require a highly performant CLIC detector. In particular the vertex detector must provide a single point resolution of only a few micrometers while not exceeding the envisaged material budget of around 0.2%$~X_0$ per layer. Beam-beam interactions and beamstrahlung processes impose an additional requirement on the timestamping capabilities of the vertex detector of about 10 ns. These goals can only be met by using novel techniques in the sensor and ASIC design as well as in the detector construction. The R&D program for the CLIC vertex detector explores various technologies in order to meet these demands. The feasibility of planar sensors with a thickness of 50–150$~\\mu$m, including different active edge designs, are evaluated using Timepix3 A...

  2. Spin wave Feynman diagram vertex computation package

    Science.gov (United States)

    Price, Alexander; Javernick, Philip; Datta, Trinanjan

    Spin wave theory is a well-established theoretical technique that can correctly predict the physical behavior of ordered magnetic states. However, computing the effects of an interacting spin wave theory incorporating magnons involve a laborious by hand derivation of Feynman diagram vertices. The process is tedious and time consuming. Hence, to improve productivity and have another means to check the analytical calculations, we have devised a Feynman Diagram Vertex Computation package. In this talk, we will describe our research group's effort to implement a Mathematica based symbolic Feynman diagram vertex computation package that computes spin wave vertices. Utilizing the non-commutative algebra package NCAlgebra as an add-on to Mathematica, symbolic expressions for the Feynman diagram vertices of a Heisenberg quantum antiferromagnet are obtained. Our existing code reproduces the well-known expressions of a nearest neighbor square lattice Heisenberg model. We also discuss the case of a triangular lattice Heisenberg model where non collinear terms contribute to the vertex interactions.

  3. Markov branching in the vertex splitting model

    International Nuclear Information System (INIS)

    Stefánsson, Sigurdur Örn

    2012-01-01

    We study a special case of the vertex splitting model which is a recent model of randomly growing trees. For any finite maximum vertex degree D, we find a one parameter model, with parameter α element of [0,1] which has a so-called Markov branching property. When D=∞ we find a two parameter model with an additional parameter γ element of [0,1] which also has this feature. In the case D = 3, the model bears resemblance to Ford's α-model of phylogenetic trees and when D=∞ it is similar to its generalization, the αγ-model. For α = 0, the model reduces to the well known model of preferential attachment. In the case α > 0, we prove convergence of the finite volume probability measures, generated by the growth rules, to a measure on infinite trees which is concentrated on the set of trees with a single spine. We show that the annealed Hausdorff dimension with respect to the infinite volume measure is 1/α. When γ = 0 the model reduces to a model of growing caterpillar graphs in which case we prove that the Hausdorff dimension is almost surely 1/α and that the spectral dimension is almost surely 2/(1 + α). We comment briefly on the distribution of vertex degrees and correlations between degrees of neighbouring vertices

  4. Complex growing networks with intrinsic vertex fitness

    International Nuclear Information System (INIS)

    Bedogne, C.; Rodgers, G. J.

    2006-01-01

    One of the major questions in complex network research is to identify the range of mechanisms by which a complex network can self organize into a scale-free state. In this paper we investigate the interplay between a fitness linking mechanism and both random and preferential attachment. In our models, each vertex is assigned a fitness x, drawn from a probability distribution ρ(x). In Model A, at each time step a vertex is added and joined to an existing vertex, selected at random, with probability p and an edge is introduced between vertices with fitnesses x and y, with a rate f(x,y), with probability 1-p. Model B differs from Model A in that, with probability p, edges are added with preferential attachment rather than randomly. The analysis of Model A shows that, for every fixed fitness x, the network's degree distribution decays exponentially. In Model B we recover instead a power-law degree distribution whose exponent depends only on p, and we show how this result can be generalized. The properties of a number of particular networks are examined

  5. A discriminator with a current-sum multiplicity output for the PHENIX multiplicity vertex detector

    International Nuclear Information System (INIS)

    Smith, R.S.; Kennedy, E.J.; Jackson, R.G.

    1996-01-01

    A current output multiplicity discriminator for use in the front-end electronics (FEE) of the Multiplicity Vertex Detector (MVD) for the PHENIX detector at RHIC has been fabricated in the a 1.2-micro CMOS, n-well process. The discriminator is capable of triggering on input signals ranging from 0.25 MIP to 5 MIP. Frequency response of the discriminator is such that the circuit is capable of generating an output for every bunch crossing (105 ns) of the RHIC collider. Channel-to-channel threshold matching was adjustable to ± 4 mV. One channel of multiplicity discriminator occupied an area of 85 micro x 630 micro and consumed 515 microW from a single 5-V supply. Details of the design and results from prototype device testing are presented

  6. Calibration of the forward and rear ZEUS calorimeter using cosmic ray muons

    International Nuclear Information System (INIS)

    Behrens, U.; Freidhof, A.; Fuertjes, A.; Mitchell, J.; Molthagen, K.; Tsurugai, T.; Yoshida, R.

    1993-08-01

    The forward and rear calorimeter of the ZEUS experiment consists of 48 modules. Before their installation into the ZEUS detector they were calibrated at DESY using cosmic ray muons in order to check their performance and to compare the response to cosmic muons to the response, obtained for some modules, to 100 GeV beam muons. The set-up, the test procedure and the analysis of the data are described in this paper. The relative calibration of the different modules, as well as of the different cells within a module can be obtained with cosmic ray muons with an accuracy of about one percent for a measurement time of 3-5 days/module. (orig.)

  7. Study of gamma propagation by using the ZEUS mono-kinetic code

    International Nuclear Information System (INIS)

    Vergnaud, Therese

    1969-10-01

    As studies of radiation protection often require the knowledge of heating due to capture gamma of thermal neutrons, the authors report an attempt of assessment of neutrons and γ propagation by using the same code (Zeus) which computes particle scattering by implementing a mono-kinetic Monte Carlo method. With this method, it is possible to study rather complex geometries and gamma source distributions directly obtained by a previous calculation of thermal neutrons. However, this method is not suitable for the study of energy degradation of gamma rays during their propagation. An approximate shock law is used to take shock-induced energy loss into account. This method is tested for different materials or media (either light like water and aluminium, or heavy like iron). Results are compared with those obtained by Goldstein with the method of moments. Results obtained by using Zeus are discussed: some of them appear to be over-estimated [fr

  8. Measurement of the luminosity in the ZEUS experiment at HERA II

    Energy Technology Data Exchange (ETDEWEB)

    Adamczyk, L.; Bold, T. [AGH Univ. of Science and Technology, Cracow (Poland); Andruszkow, J. [Polish Academy of Sciences, Cracow (Poland). Inst. of Nuclear Physics] [and others

    2013-06-15

    The luminosity in the ZEUS detector was measured using photons from electron bremsstrahlung. In 2001 the HERA collider was upgraded for operation at higher luminosity. At the same time the luminosity-measuring system of the ZEUS experiment was modified to tackle the expected higher photon rate and synchrotron radiation. The existing lead-scintillator calorimeter was equipped with radiation hard scintillator tiles and shielded against synchrotron radiation. In addition, a magnetic spectrometer was installed to measure the luminosity independently using photons converted in the beam-pipe exit window. The redundancy provided a reliable and robust luminosity determination with a systematic uncertainty of 1.7%. The experimental setup, the techniques used for luminosity determination and the estimate of the systematic uncertainty are reported.

  9. A measuring facility for the uniformization of the optical readout at the ZEUS calorimeter

    International Nuclear Information System (INIS)

    Jahnen, G.

    1988-10-01

    The ZEUS-detector for HERA features a high resolution calorimeter of the sampling type. The passive layers are made of depleted uranium and the active layers are of aromatic scintillator. The layer thicknesses are chosen to yield full compensation, i.e. for a given energy electrons or photons produce the same signal as hadrons or jets. The scintillators are read out via wave length shifter bars. A uniform response of the wave length shifter i.e. a response independent of the entrance position of the scintillator light, is essential to obtain best possible resolution. This diploma thesis concentrates on the apparatus and the procedure to produce wave length shifters for the electromagnetic sections of the ZEUS forward calorimeter to better than ±2%. (orig.) [de

  10. Identification and angle reconstruction of the scattered electron with the ZEUS calorimeter

    International Nuclear Information System (INIS)

    Doeker, T.

    1992-10-01

    For the analysis of deep-inelastic electron-proton events with the ZEUS detector, a key ingredient is the reliable and efficient identification of a scattered electron. To this end an essential mean is the information from the uranium-scintillator calorimeter. In this work an algorithm is presented which uses the segmentation properties of the ZEUS calorimeter to identify the scattered electron in neutral current events. For energy deposits in adjacent calorimeter cells the algorithm determines the probability that these deposits result from an electromagnetic shower. Furthermore several methods of measuring the scattering angle of the final state electron are compared. An angular resolution of about 3 mrad is obtained. (orig.) [de

  11. Measurement of the longitudinal proton structure function with the ZEUS detector at HERA

    International Nuclear Information System (INIS)

    Grebenyuk, Julia

    2010-01-01

    The reduced neutral current cross sections for ep deep inelastic scattering have been measured with the ZEUS detector at HERA at three different centre-of-mass energies, 318, 251 and 225 GeV. The reduced cross sections were measured double differentially in Bjorken x and the virtuality Q 2 . From these the proton structure functions F L and F 2 have been extracted in the region 5 x 10 -4 ZEUS measured reduced cross sections were combined with results from the H1 collaboration, in the region 2.4 x 10 -4

  12. The LST analog read-out system of the ZEUS muon detector

    International Nuclear Information System (INIS)

    De Giorgi, M.; Abbiendi, G.; Bertolin, A.; Borsato, E.; Brugnera, R.; Carlin, R.; Dal Corso, F.; Dosselli, U.; Gasparini, F.; Limentani, S.; Morandin, M.; Pitacco, G.; Posocco, M.; Stanco, L.; Stroili, R.; Voci, C.; Zuin, F.

    1996-01-01

    A muon position detector based on limited streamer tubes has been built for the ZEUS experiment at the HERA e-p collider at Desy. The tubes are arranged in chambers equipped with electronics circuitry providing an analog read-out of induced signals on strips set orthogonal to the tube wires. The electronic module for charge amplification and conversion will be described including some results obtained from the complete system. (orig.)

  13. Numerical indications on the semiclassical limit of the flipped vertex

    Energy Technology Data Exchange (ETDEWEB)

    Magliaro, Elena; Perini, Claudio; Rovelli, Carlo [Centre de Physique Theorique de Luminy , Case 907, F-13288 Marseille (France)

    2008-05-07

    We introduce a technique for testing the semiclassical limit of a quantum gravity vertex amplitude. The technique is based on the propagation of a semiclassical wave packet. We apply this technique to the newly introduced 'flipped' vertex in loop quantum gravity, in order to test the intertwiner dependence of the vertex. Under some drastic simplifications, we find very preliminary, but surprisingly good numerical evidence for the correct classical limit.

  14. Mechanical design of the CDF SVX II silicon vertex detector

    International Nuclear Information System (INIS)

    Skarha, J.E.

    1994-08-01

    A next generation silicon vertex detector is planned at CDF for the 1998 Tevatron collider run with the Main Injector. The SVX II silicon vertex detector will allow high luminosity data-taking, enable online triggering of secondary vertex production, and greatly increase the acceptance for heavy flavor physics at CDF. The design specifications, geometric layout, and early mechanical prototyping work for this detector are discussed

  15. Loop vertex expansion for higher-order interactions

    Science.gov (United States)

    Rivasseau, Vincent

    2018-05-01

    This note provides an extension of the constructive loop vertex expansion to stable interactions of arbitrarily high order, opening the way to many applications. We treat in detail the example of the (\\bar{φ } φ )^p field theory in zero dimension. We find that the important feature to extend the loop vertex expansion is not to use an intermediate field representation, but rather to force integration of exactly one particular field per vertex of the initial action.

  16. Pion-nucleon vertex function with one nucleon off shell

    International Nuclear Information System (INIS)

    Mizutani, T.; Rochus, P.

    1979-01-01

    The pion-nucleon vertex function with an off-mass-shell nucleon is obtained through sideways dispersion relations with the P 11 and S 11 pion-nucleon phase shifts as only input. Contrary to the recent calculation of Nutt and Shakin, we find that the proper and improper vertex functions behave quite differently, indicating the importance of the nucleon propagator dressing. In particular the proper vertex function is found to have two poles in the unphysical region

  17. The Belle II Silicon Vertex Detector

    Energy Technology Data Exchange (ETDEWEB)

    Friedl, M., E-mail: markus.friedl@oeaw.ac.at [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Ackermann, K. [MPI Munich, Föhringer Ring 6, 80805 München (Germany); Aihara, H. [University of Tokyo, Department of Physics, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Aziz, T. [Tata Institute of Fundamental Research, Experimental High Energy Physics Group, Homi Bhabha Road, Mumbai 400 005 (India); Bergauer, T. [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Bozek, A. [Institute of Nuclear Physics, Division of Particle Physics and Astrophysics, ul. Radzikowskiego 152, 31 342 Krakow (Poland); Campbell, A. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Dingfelder, J. [University of Bonn, Department of Physics and Astronomy, Nussallee 12, 53115 Bonn (Germany); Drasal, Z. [Charles University, Institute of Particle and Nuclear Physics, Ke Karlovu 3, 121 16 Praha 2 (Czech Republic); Frankenberger, A. [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Gadow, K. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Gfall, I. [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Haba, J.; Hara, K.; Hara, T. [KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Higuchi, T. [University of Tokyo, Kavli Institute for Physics and Mathematics of the Universe, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Himori, S. [Tohoku University, Department of Physics, Aoba Aramaki Aoba-ku, Sendai 980-8578 (Japan); Irmler, C. [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Ishikawa, A. [Tohoku University, Department of Physics, Aoba Aramaki Aoba-ku, Sendai 980-8578 (Japan); Joo, C. [Seoul National University, High Energy Physics Laboratory, 25-107 Shinlim-dong, Kwanak-gu, Seoul 151-742 (Korea, Republic of); and others

    2013-12-21

    The KEKB machine and the Belle experiment in Tsukuba (Japan) are now undergoing an upgrade, leading to an ultimate luminosity of 8×10{sup 35}cm{sup −2}s{sup −1} in order to measure rare decays in the B system with high statistics. The previous vertex detector cannot cope with this 40-fold increase of luminosity and thus needs to be replaced. Belle II will be equipped with a two-layer Pixel Detector surrounding the beam pipe, and four layers of double-sided silicon strip sensors at higher radii than the old detector. The Silicon Vertex Detector (SVD) will have a total sensitive area of 1.13m{sup 2} and 223,744 channels—twice as many as its predecessor. All silicon sensors will be made from 150 mm wafers in order to maximize their size and thus to reduce the relative contribution of the support structure. The forward part has slanted sensors of trapezoidal shape to improve the measurement precision and to minimize the amount of material as seen by particles from the vertex. Fast-shaping front-end amplifiers will be used in conjunction with an online hit time reconstruction algorithm in order to reduce the occupancy to the level of a few percent at most. A novel “Origami” chip-on-sensor scheme is used to minimize both the distance between strips and amplifier (thus reducing the electronic noise) as well as the overall material budget. This report gives an overview on the status of the Belle II SVD and its components, including sensors, front-end detector ladders, mechanics, cooling and the readout electronics.

  18. The Belle II Silicon Vertex Detector

    International Nuclear Information System (INIS)

    Friedl, M.; Ackermann, K.; Aihara, H.; Aziz, T.; Bergauer, T.; Bozek, A.; Campbell, A.; Dingfelder, J.; Drasal, Z.; Frankenberger, A.; Gadow, K.; Gfall, I.; Haba, J.; Hara, K.; Hara, T.; Higuchi, T.; Himori, S.; Irmler, C.; Ishikawa, A.; Joo, C.

    2013-01-01

    The KEKB machine and the Belle experiment in Tsukuba (Japan) are now undergoing an upgrade, leading to an ultimate luminosity of 8×10 35 cm −2 s −1 in order to measure rare decays in the B system with high statistics. The previous vertex detector cannot cope with this 40-fold increase of luminosity and thus needs to be replaced. Belle II will be equipped with a two-layer Pixel Detector surrounding the beam pipe, and four layers of double-sided silicon strip sensors at higher radii than the old detector. The Silicon Vertex Detector (SVD) will have a total sensitive area of 1.13m 2 and 223,744 channels—twice as many as its predecessor. All silicon sensors will be made from 150 mm wafers in order to maximize their size and thus to reduce the relative contribution of the support structure. The forward part has slanted sensors of trapezoidal shape to improve the measurement precision and to minimize the amount of material as seen by particles from the vertex. Fast-shaping front-end amplifiers will be used in conjunction with an online hit time reconstruction algorithm in order to reduce the occupancy to the level of a few percent at most. A novel “Origami” chip-on-sensor scheme is used to minimize both the distance between strips and amplifier (thus reducing the electronic noise) as well as the overall material budget. This report gives an overview on the status of the Belle II SVD and its components, including sensors, front-end detector ladders, mechanics, cooling and the readout electronics

  19. Propagation of the trip behavior in the VENUS vertex chamber

    International Nuclear Information System (INIS)

    Ohama, Taro; Yamada, Yoshikazu.

    1995-03-01

    The high voltage system of the VENUS vertex chamber occasionally trips by a discharge somewhere among cathode electrodes during data taking. This trip behavior induces often additional trips at other electrodes such as the skin and the grid electrodes in the vertex chamber. This propagation mechanism of trips is so complicated in this system related with multi-electrodes. Although the vertex chamber is already installed inside the VENUS detector and consequently the discharge is not able to observe directly, a trial to estimate the propagation has been done using only the information which appears around the trip circuits and the power supply of the vertex chamber. (author)

  20. The Mark II Vertex Drift Chamber

    International Nuclear Information System (INIS)

    Alexander, J.P.; Baggs, R.; Fujino, D.

    1989-03-01

    We have completed constructing and begun operating the Mark II Drift Chamber Vertex Detector. The chamber, based on a modified jet cell design, achieves 30 μm spatial resolution and 2 gas mixtures. Special emphasis has been placed on controlling systematic errors including the use of novel construction techniques which permit accurate wire placement. Chamber performance has been studied with cosmic ray tracks collected with the chamber located both inside and outside the Mark II. Results on spatial resolution, average pulse shape, and some properties of CO 2 mixtures are presented. 10 refs., 12 figs., 1 tab

  1. Loop-quantum-gravity vertex amplitude.

    Science.gov (United States)

    Engle, Jonathan; Pereira, Roberto; Rovelli, Carlo

    2007-10-19

    Spin foam models are hoped to provide the dynamics of loop-quantum gravity. However, the most popular of these, the Barrett-Crane model, does not have the good boundary state space and there are indications that it fails to yield good low-energy n-point functions. We present an alternative dynamics that can be derived as a quantization of a Regge discretization of Euclidean general relativity, where second class constraints are imposed weakly. Its state space matches the SO(3) loop gravity one and it yields an SO(4)-covariant vertex amplitude for Euclidean loop gravity.

  2. Vertex ring-indexed Lie algebras

    International Nuclear Information System (INIS)

    Fairlie, David; Zachos, Cosmas

    2005-01-01

    Infinite-dimensional Lie algebras are introduced, which are only partially graded, and are specified by indices lying on cyclotomic rings. They may be thought of as generalizations of the Onsager algebra, but unlike it, or its sl(n) generalizations, they are not subalgebras of the loop algebras associated with sl(n). In a particular interesting case associated with sl(3), their indices lie on the Eisenstein integer triangular lattice, and these algebras are expected to underlie vertex operator combinations in CFT, brane physics, and graphite monolayers

  3. Construction of the CDF silicon vertex detector

    International Nuclear Information System (INIS)

    Skarha, J.; Barnett, B.; Boswell, C.; Snider, F.; Spies, A.; Tseng, J.; Vejcik, S.; Carter, H.; Flaugher, B.; Gonzales, B.; Hrycyk, M.; Nelson, C.; Segler, S.; Shaw, T.; Tkaczyk, S.; Turner, K.; Wesson, T.; Carithers, W.; Ely, R.; Haber, C.; Holland, S.; Kleinfelder, S.; Merrick, T.; Schneider, O.; Wester, W.; Wong, M.; Amidei, D.; Derwent, P.; Gold, M.; Matthews, J.; Bacchetta, N.; Bisello, D.; Busetto, G.; Castro, A.; Loreti, M.; Pescara, L.; Bedeschi, F.; Bolognesi, V.; Dell'Agnello, S.; Galeotti, S.; Mariotti, M.; Menzione, A.; Punzi, G.; Raffaelli, F.; Risotri, L.; Tartarelli, F.; Turini, N.; Wenzel, H.; Zetti, F.; Bailey, M.; Garfinkel, A.; Shaw, N.; Tipton, P.; Watts, G.

    1992-04-01

    Technical details and methods used in constructing the CDF silicon vertex detector are presented. This description includes a discussion of the foam-carbon fiber composite structure used to silicon microstrip detectors and the procedure for achievement of 5 μm detector alignment. The construction of the beryllium barrel structure, which houses the detector assemblies, is also described. In addition, the 10 μm placement accuracy of the detectors in the barrel structure is discussed and the detector cooling and mounting systems are described. 12 refs

  4. Developments in solid state vertex detectors

    International Nuclear Information System (INIS)

    Damerell, C.J.S.

    1984-12-01

    Since the discovery of the J/psi in November 1974, there has been a strong interest in the physics of particles containing higher-flavour quarks (charm, bottom, top, ...). High precision vertex detectors can be used to identify the decay products of parent particles which have lifetimes of the order 10 -13 s. The paper surveys the progress which is being made in developing silicon detectors with the necessary tracking precision (< approx. 5 μm) to be used for this purpose in fixed target experiments and also in colliders such as SLC and LEP. (author)

  5. Silicon detectors for tracking and vertexing

    International Nuclear Information System (INIS)

    Nomerotski, Andrei

    2009-01-01

    This review covers recent developments in silicon detectors used for particle physics experiments for the tracking and vertexing systems. After a general introduction the main focus of the report is on new challenges for this field posed by requirements of the future generation machines. Technologies reviewed in more detail are column parallel CCDs, DEPFET, vertical integration of sensors and electronics and several others which allow fast readout and low mass design. Important system issues such as mechanical arrangements for the sensors and power distribution, which are critical for the low mass design, are also discussed.

  6. Quantum Vertex Model for Reversible Classical Computing

    Science.gov (United States)

    Chamon, Claudio; Mucciolo, Eduardo; Ruckenstein, Andrei; Yang, Zhicheng

    We present a planar vertex model that encodes the result of a universal reversible classical computation in its ground state. The approach involves Boolean variables (spins) placed on links of a two-dimensional lattice, with vertices representing logic gates. Large short-ranged interactions between at most two spins implement the operation of each gate. The lattice is anisotropic with one direction corresponding to computational time, and with transverse boundaries storing the computation's input and output. The model displays no finite temperature phase transitions, including no glass transitions, independent of circuit. The computational complexity is encoded in the scaling of the relaxation rate into the ground state with the system size. We use thermal annealing and a novel and more efficient heuristic \\x9Dannealing with learning to study various computational problems. To explore faster relaxation routes, we construct an explicit mapping of the vertex model into the Chimera architecture of the D-Wave machine, initiating a novel approach to reversible classical computation based on quantum annealing.

  7. The Construction of Spin Foam Vertex Amplitudes

    Directory of Open Access Journals (Sweden)

    Eugenio Bianchi

    2013-01-01

    Full Text Available Spin foam vertex amplitudes are the key ingredient of spin foam models for quantum gravity. These fall into the realm of discretized path integral, and can be seen as generalized lattice gauge theories. They can be seen as an attempt at a 4-dimensional generalization of the Ponzano-Regge model for 3d quantum gravity. We motivate and review the construction of the vertex amplitudes of recent spin foam models, giving two different and complementary perspectives of this construction. The first proceeds by extracting geometric configurations from a topological theory of the BF type, and can be seen to be in the tradition of the work of Barrett, Crane, Freidel and Krasnov. The second keeps closer contact to the structure of Loop Quantum Gravity and tries to identify an appropriate set of constraints to define a Lorentz-invariant interaction of its quanta of space. This approach is in the tradition of the work of Smolin, Markopoulous, Engle, Pereira, Rovelli and Livine.

  8. A hadron-quark vertex function

    International Nuclear Information System (INIS)

    Mitra, A.N.; Bhatnagar, S.

    1992-01-01

    This paper reports that the interrelation between the 4D and 3D forms of the Bethe-Salpeter equation (BSE) with a kernel K(q,q') which depends on the relative four-momenta, q μ = q μ - P · qP μ /P 2 , orthogonal to P μ is exploited to obtain a hadron-quark vertex function of the Lorentz-invariant form Γ(q) = D(q 2 ) circle time φ(q). The denominator function D(q 2 ) is universal and controls the 3D BSE, which provides the mass spectra with the eigenfunctions φ(q). The vertex function, directly related to the 4D wave function Ψ which satisfies a corresponding BSE, defines a natural off-shell extension over the whole of four-momentum space, and provides the basis for the evaluation of transition amplitudes via appropriate quark-loop diagrams. The key role of the quantity q 2 in this formalism is clarified in relation to earlier approaches, in which the applications of this quantity had mostly been limited to the mass shell (q · P = 0). Two applications (f p values for P → ell bar ell and F π for π 0 → γγ) are sketched as illustrations of this formalism, and attention is drawn to the problem of complex amplitudes for bigger quark loops with more hadrons, together with the role of the D(q) function in overcoming this problem

  9. Vertex models, TASEP and Grothendieck polynomials

    International Nuclear Information System (INIS)

    Motegi, Kohei; Sakai, Kazumitsu

    2013-01-01

    We examine the wavefunctions and their scalar products of a one-parameter family of integrable five-vertex models. At a special point of the parameter, the model investigated is related to an irreversible interacting stochastic particle system—the so-called totally asymmetric simple exclusion process (TASEP). By combining the quantum inverse scattering method with a matrix product representation of the wavefunctions, the on-/off-shell wavefunctions of the five-vertex models are represented as a certain determinant form. Up to some normalization factors, we find that the wavefunctions are given by Grothendieck polynomials, which are a one-parameter deformation of Schur polynomials. Introducing a dual version of the Grothendieck polynomials, and utilizing the determinant representation for the scalar products of the wavefunctions, we derive a generalized Cauchy identity satisfied by the Grothendieck polynomials and their duals. Several representation theoretical formulae for the Grothendieck polynomials are also presented. As a byproduct, the relaxation dynamics such as Green functions for the periodic TASEP are found to be described in terms of the Grothendieck polynomials. (paper)

  10. BTeV detached vertex trigger

    International Nuclear Information System (INIS)

    Gottschalk, E.E.

    2001-01-01

    BTeV is a collider experiment that has been approved to run in the Tevatron at Fermilab. The experiment will conduct precision studies of CP violation using a forward-geometry detector. The detector will be optimized for high-rate detection of beauty and charm particles produced in collisions between protons and anti-protons. BTeV will trigger on beauty and charm events by taking advantage of the main difference between these heavy quark events and more typical hadronic events - the presence of detached beauty and charm decay vertices. The first stage of the BTeV trigger will receive data from a pixel vertex detector at a rate of 100 gb s -1 , reconstruct tracks and vertices for every beam crossing, reject 99% of beam crossings that do not produce beauty or charm particles, and trigger on beauty events with high efficiency. An overview of the trigger design and its influence on the design of the pixel vertex detector is presented

  11. Tracking and Vertexing with the ATLAS Inner Detector in the LHC Run2 and Beyond

    CERN Document Server

    Swift, Stewart Patrick; The ATLAS collaboration

    2017-01-01

    Run-2 of the LHC has provided new challenges to track and vertex reconstruction with higher centre-of-mass energies and luminosity leading to increasingly high-multiplicity environments, boosted, and highly-collimated physics objects. To achieve this goal, ATLAS is equipped with the Inner Detector tracking system built using different technologies, silicon planar sensors (pixel and micro-strip) and gaseous drift- tubes, all embedded in a 2T solenoidal magnetic field. In addition, the Insertable B-layer (IBL) is a fourth pixel layer, which was inserted at the centre of ATLAS during the first long shutdown of the LHC. An overview of the use of each of these subdetectors in track and vertex reconstruction, as well as the algorithmic approaches taken to the specific tasks of pattern recognition and track fitting, is given. The performance of the Inner Detector tracking and vertexing will be summarised. These include a factor of three reduction in the reconstruction time, optimisation for the expected conditions, ...

  12. TRACKING AND VERTEXING WITH THE ATLAS INNER DETECTOR IN THE LHC RUN2 AND BEYOND

    CERN Document Server

    Choi, Kyungeon; The ATLAS collaboration

    2017-01-01

    Run-2 of the LHC has provided new challenges to track and vertex reconstruction with higher centre-of-mass energies and luminosity leading to increasingly high-multiplicity environments, boosted, and highly-collimated physics objects. To achieve this goal, ATLAS is equipped with the Inner Detector tracking system built using different technologies, silicon planar sensors (pixel and micro-strip) and gaseous drift- tubes, all embedded in a 2T solenoidal magnetic field. In addition, the Insertable B-layer (IBL) is a fourth pixel layer, which was inserted at the centre of ATLAS during the first long shutdown of the LHC. An overview of the use of each of these subdetectors in track and vertex reconstruction, as well as the algorithmic approaches taken to the specific tasks of pattern recognition and track fitting, is given. The performance of the Inner Detector tracking and vertexing will be summarised. These include a factor of three reduction in the reconstruction time, optimisation for the expected conditions, ...

  13. Design of a secondary-vertex trigger system

    International Nuclear Information System (INIS)

    Husby, D.; Chew, P.; Sterner, K.; Selove, W.

    1995-06-01

    For the selection of beauty and charm events with high efficiency at the Tevatron, a secondary-vertex trigger system is under design. It would operate on forward-geometry events. The system would use on-line tracking of all tracks in the vertex detector, to identify events with clearly detached secondary vertices

  14. BRST invariant mixed string vertex for the bosonic string

    International Nuclear Information System (INIS)

    Clarizia, A.; Pezzella, F.

    1987-09-01

    We construct a BRST invariant (N+M)-string vertex including both open and closed string states. When we saturate it with N open string and M closed string physical states it reproduces their corresponding scattering amplitude. As a particular case we obtain BRST invariant vertex for the open-closed string transition. (orig.)

  15. Drift chamber vertex detectors for SLC/LEP

    International Nuclear Information System (INIS)

    Hayes, K.G.

    1987-03-01

    The short but measurable lifetimes of the b and c quarks and the tau lepton have motivated the development of high precision tracking detectors capable of providing information on the decay vertex topology of events containing these particles. This paper reviews the OPAL, L3, and MARK II experiments vertex drift chambers

  16. Algebraic Bethe ansatz for 19-vertex models with reflection conditions

    International Nuclear Information System (INIS)

    Utiel, Wagner

    2003-01-01

    In this work we solve the 19-vertex models with the use of algebraic Bethe ansatz for diagonal reflection matrices (Sklyanin K-matrices). The eigenvectors, eigenvalues and Bethe equations are given in a general form. Quantum spin chains of spin one derived from the 19-vertex models were also discussed

  17. Graphs with No Induced Five-Vertex Path or Antipath

    DEFF Research Database (Denmark)

    Chudnovsky, Maria; Esperet, Louis; Lemoine, Laetitia

    2017-01-01

    We prove that a graph G contains no induced five-vertex path and no induced complement of a five-vertex path if and only if G is obtained from 5-cycles and split graphs by repeatedly applying the following operations: substitution, split unification, and split unification in the complement, where...

  18. Drift chamber vertex detectors for SLC/LEP

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, K G

    1988-03-01

    Factors influencing the design of drift chamber vertex detectors for SLC and LEP are discussed including global strategy, chamber gas, cell design, and signal processing. The designs of the vertex chambers for the L3 and OPAL experiments at LEP and the Mark II experiment at the SLC are described.

  19. Fermionic construction of vertex operators for twisted affine algebras

    International Nuclear Information System (INIS)

    Frappat, L.; Sorba, P.; Sciarrino, A.

    1988-03-01

    We construct vertex operator representations of the twisted affine algebras in terms of fermionic (or parafermionic in some cases) elementary fields. The folding method applied to the extended Dynkin diagrams of the affine algebras allows us to determine explicitly these fermionic fields as vertex operators

  20. Vertex epidural haematoma manifesting with bilateral upper limb ...

    African Journals Online (AJOL)

    Vertex epidural haematomas (VEDH) are rare and difficulties are encountered in diagnosis and management. This is a case report of a patient with a vertex epidural haematoma who presented with signs of severe head injury with upper limb decerebrate posture. We discuss the challenges of radiological investigation and ...

  1. Subgraphs in vertex neighborhoods of K-free graphs

    DEFF Research Database (Denmark)

    Bang-Jensen, J.; Brandt, Stephan

    2004-01-01

    In a K-free graph, the neighborhood of every vertex induces a K-free subgraph. The K-free graphs with the converse property that every induced K-free subgraph is contained in the neighborhood of a vertex are characterized, based on the characterization in the case r = 3 due to Pach [8]....

  2. Multipole expansion of vertex functions with two final particles

    International Nuclear Information System (INIS)

    Daumens, Michel

    1977-01-01

    The expansions of the usual vertex functions are generalized to the vertex functions with two final particles. For four vector functions, expressions are similar to those of Chew, Goldberger, Low and Nambu, and of Adler and the consequences of the isobaric model are studied [fr

  3. The Mark III vertex chamber and prototype test results

    International Nuclear Information System (INIS)

    Grab, C.

    1987-07-01

    A vertex chamber has been constructed for use in the Mark III experiment. The chamber is positioned inside the current main drift chamber and will be used to trigger data collection, to aid in vertex reconstruction, and to improve the momentum resolution. This paper discusses the chamber's construction and performance and tests of the prototype

  4. On Pathos Adjacency Cut Vertex Jump Graph of a Tree

    OpenAIRE

    Nagesh.H.M; R.Chandrasekhar

    2014-01-01

    In this paper the concept of pathos adjacency cut vertex jump graph PJC(T) of a tree T is introduced. We also present a characterization of graphs whose pathos adjacency cut vertex jump graphs are planar, outerplanar, minimally non-outerplanar, Eulerian and Hamiltonian.

  5. Vertex Accentuation in Female Pattern Hair Loss in Asians

    Directory of Open Access Journals (Sweden)

    Chavalit Supsrisunjai

    2016-05-01

    Full Text Available Background: The most common cause of hair loss seen in women is female pattern hair loss (FPHL, also known as female androgenetic alopecia. It affects the central part of the scalp, but spares the frontal hairline. Frontal accentuation was also described by Olsen. In Asian women, vertex thinning patterns are frequently developed, but there has been no report about vertex thinning pattern in female pattern hair loss. Objective: To find prevalence of vertex accentuation in female pattern hair loss (FPHL in Asian women. Methods: Scalp hair counting (n/cm2 were measured at 3 different areas; vertex, mid scalp and frontal area respectively by digital dermoscope (Dino digital AM-413T. Visual counting and photography were performed. Outcomes were evaluated by gross appearance of vertex thinning and/or hair density <120 /cm2 in any of 3 areas. Results: 143 patients were evaluated. Mean age was 45.54 years. Of the hair loss type, 36.4% were mid-scalp, 33.6% were vertex accentuation and 30.1% were frontal accentuation, respectively. Age was not significantly different among the 3 types of hair loss (P- value 0.859. Conclusion: Although the most common female pattern hair loss type is diffuse type (Ludwig type, vertex accentuation pattern is the second most common pattern in this study. This study is the first to mention “Vertex accentuation” to be another pattern for FPHL.

  6. Genus Ranges of 4-Regular Rigid Vertex Graphs.

    Science.gov (United States)

    Buck, Dorothy; Dolzhenko, Egor; Jonoska, Nataša; Saito, Masahico; Valencia, Karin

    2015-01-01

    A rigid vertex of a graph is one that has a prescribed cyclic order of its incident edges. We study orientable genus ranges of 4-regular rigid vertex graphs. The (orientable) genus range is a set of genera values over all orientable surfaces into which a graph is embedded cellularly, and the embeddings of rigid vertex graphs are required to preserve the prescribed cyclic order of incident edges at every vertex. The genus ranges of 4-regular rigid vertex graphs are sets of consecutive integers, and we address two questions: which intervals of integers appear as genus ranges of such graphs, and what types of graphs realize a given genus range. For graphs with 2 n vertices ( n > 1), we prove that all intervals [ a, b ] for all a genus ranges. For graphs with 2 n - 1 vertices ( n ≥ 1), we prove that all intervals [ a, b ] for all a genus ranges. We also provide constructions of graphs that realize these ranges.

  7. Twisted vertex algebras, bicharacter construction and boson-fermion correspondences

    International Nuclear Information System (INIS)

    Anguelova, Iana I.

    2013-01-01

    The boson-fermion correspondences are an important phenomena on the intersection of several areas in mathematical physics: representation theory, vertex algebras and conformal field theory, integrable systems, number theory, cohomology. Two such correspondences are well known: the types A and B (and their super extensions). As a main result of this paper we present a new boson-fermion correspondence of type D-A. Further, we define a new concept of twisted vertex algebra of order N, which generalizes super vertex algebra. We develop the bicharacter construction which we use for constructing classes of examples of twisted vertex algebras, as well as for deriving formulas for the operator product expansions, analytic continuations, and normal ordered products. By using the underlying Hopf algebra structure we prove general bicharacter formulas for the vacuum expectation values for two important groups of examples. We show that the correspondences of types B, C, and D-A are isomorphisms of twisted vertex algebras

  8. Construction of the Zeus forward/rear calorimeter modules at NIKHEF

    International Nuclear Information System (INIS)

    Blankers, R.; Engelen, J.; Geerinck, H.; Homma, J.; Hunck, P.; Koning, N. de; Kooijman, P.; Korporaal, A.; Loos, R.; Straver, J.; Tiecke, H.

    1990-07-01

    ZEUS is one of the two experiments in preparation for studying electron-proton interactions at the HERA e-p collider at DESY in Hamburg. The design value for the energy of the electron beam is 30 GeV and for the proton beam 820 GeV. The asymmetry in the beam particle masses and their energies causes in general a strongly asymmetric energy distribution for the reaction products, in particular most of the energy flow will be in the proton direction. The layout of the ZEUS detector accomodates for this asymmetry. In the proton direction for instance, several wirechambers assure together with the central tracking detector good track reconstruction, in an area where high density of tracks is expected. The tracking detector is placed inside a magnetic field of 1.8 Tesla, provided by a superconducting coil. The interaction point is completely surrounded by a high resolution calorimeter, which in turn is surrounded by a backing calorimeter; this backing calorimeter has to detect late showering particles, has to serve as a muon filter and is also the return yoke for the magnetic field. The ZEUS collaboration has chosen for a type of hadron calorimeter with the best possible energy resolution known to date, a depleted uranium-scintillator sampling calorimeter. The calorimeter has an equal response to electrons and hadrons of the same energy (e/h=1). The sampling thickness is one radiation length. The calorimeter is subdivided in three components, the forward- (in proton direction), the rear- (in electron direction) and the barrel calorimeter, FCAL, RCAL and BCAL. In this report the design and assembly procedure of the FCAL/RCAL is described in detail. Furthermore the transport problems are discussed and the first calibration results obtained with beam particles are shown. (author). 5 refs.; 29 figs.; 1 tab

  9. The performance of the ZEUS central tracking detector z-by-timing electronics in a transputer based data acquisition system

    International Nuclear Information System (INIS)

    Foster, B.; Heath, G.P.; Llewellyn, T.J.; Gingrich, D.M.; Harnew, N.; Hallam-Baker, P.M.; Khatri, T.; McArthur, I.C.; Morawitz, P.; Nash, J.; Shield, P.D.; Topp-Jorgensen, S.; Wilson, F.F.; Allen, D.B.; Carter, R.C.; Jeffs, M.D.; Morrissey, M.C.; Quinton, S.P.H.; Lane, J.B.; Postranecky, M.

    1993-01-01

    The Central Tracking Detector of the ZEUS experiment employs a time difference technique to measure the z coordinate of each hit. The method provides fast, three-dimensional space point measurements which are used as input to all levels of the ZEUS trigger. Such a tracking trigger is essential in order to discriminate against events with vertices lying outside the nominal electron-proton interaction region. Since the beam crossing interval of the HERA collider is 96 ns, all data must be pipelined through the front-end readout electronics. Subsequent data aquisition employs a novel technique which utilizes a network of approximately 120 INMOS transputers to process the data in parallel. The z-by-timing method and its data aquisition have been employed successfully in recording and reconstructing tracks from electron-proton interactions in ZEUS. (orig.)

  10. Resistance Distances in Vertex-Face Graphs

    Science.gov (United States)

    Shangguan, Yingmin; Chen, Haiyan

    2018-01-01

    The computation of two-point resistances in networks is a classical problem in electric circuit theory and graph theory. Let G be a triangulation graph with n vertices embedded on an orientable surface. Define K(G) to be the graph obtained from G by inserting a new vertex vϕ to each face ϕ of G and adding three new edges (u, vϕ), (v, vϕ) and (w, vϕ), where u, v and w are three vertices on the boundary of ϕ. In this paper, using star-triangle transformation and resistance local-sum rules, explicit relations between resistance distances in K(G) and those in G are obtained. These relations enable us to compute resistance distance between any two points of Kk(G) recursively. As explanation examples, some resistances in several networks are computed, including the modified Apollonian network and networks constructed from tetrahedron, octahedron and icosahedron, respectively.

  11. Report of the 'Vertex detector' working group

    International Nuclear Information System (INIS)

    Bellini, G.; Rancoita, P.G.

    1984-01-01

    An analysis, even rough, of the vertex detector performances, based on the pattern recognition and on currently available techniques (see below) makes clear that the high repetition rate option is strongly favoured. In this hypothesis, with a luminosity of approx.= 3 x 10 32 cm -2 s -1 and a time between bunch collision approx.= 25 ns, we expect = 1 as number of events per bunch collision, e.i. 36.8% of events with 0 interaction, 36.8% with 1 and 26.4% with more than 1 event. Two or three events per crossing bunch can be separated and 25 ns of repetition time does not appear to be a major problem. (orig./HSI)

  12. Quarkonium decays: Testing the 3-gluon vertex

    International Nuclear Information System (INIS)

    Koller, K.; Walsh, T.F.; Zerwas, P.M.; Technische Hochschule Aachen

    1980-12-01

    We study the 3-jet decays of S and P-wave quarkonia with C = +. If observed, some of these will offer a way of seeing the 3G vertex of QCD via 1 Ssub(o), 3 Psub(o), 3 P 2 (Qanti Q) → GGG + Gqanti q → 3 jets. (As is well-known, cancellations reduce 3 P 1 (anti Q) → GGG.) We elaborate in detail the S-wave decay as it is expected to show all the characteristic features of orthoquarkonium decays into 4 jets, 3 S 1 (Qanti Q) → GGGG + GGqanti q → 4 jets which we will comment upon. These quarkonium decays offer a very clear signal for QCD as a non-abelian local gauge field theory with color-charged gluons. (orig.)

  13. Primary Vertex Reconstruction for Upgrade at LHCb

    CERN Document Server

    Wanczyk, Joanna

    2016-01-01

    The aim of the LHCb experiment is the study of beauty and charm hadron decays with the main focus on CP violating phenomena and searches for physics beyond the Standard Model through rare decays. At the present, the second data taking period is ongoing, which is called Run II. After 2018 during the long shutdown, the replacement of signicant parts of the LHCb detector is planned. One of main changes is upgrade of the present software and hardware trigger to a more rapid full software trigger. Primary Vertex (PV) is a basis for the further tracking and it is sensitive to the LHC running conditions, which are going to change for the Upgrade. In particular, the center-of-mass collision energy should reach the maximum value of 14 TeV. As a result the quality of the reconstruction has to be studied and the reconstruction algorithms have to be optimized.

  14. Lifetime tests for MAC vertex chamber

    International Nuclear Information System (INIS)

    Nelson, H.

    1986-01-01

    A vertex chamber for MAC was proposed in fall 1983 to increase precision in the measurement of the B hadron and tau lepton lifetimes. The chamber had to be placed within the existing central drift chamber, making access for repairs difficult and costly. Therefore for detector elements thin-walled aluminized mylar drift tubes (straws) were used because of their simplicity and robustness. The diameter of the drift tubes was 6.9 mm. The radial extent of the proposed chamber was from 3 cm to 10 cm, the inner wall of the central drift. It was clear that radiation levels, from synchrotron x-rays and overfocussed electrons, were potentially high. Since the drift distance is short in the straws, it was desirable to operate them at the highest possible gas gain, to achieve the best spatial resolution. There was a likelihood of drawing large currents in the chamber and thus causing radiation damage. Therefore a study of radiation hardness under the conditions of their proposed design was undertaken. In tests, argon-hydrocarbon mixtures consistently became unusable at ∼0.05 C/cm collected charge, due to anode buildup. Argon-CO 2 mixtures, while underquenched, were operational to 0.25 C/cm, at which point loss of cathode material became intolerable. Argon-xenon-CO 2 proved to be quenched as well as argon-hydrocarbons, but was limited by cathode damage. The MAC vertex chamber has operated at a distance of 4.6 cm from the e + e - interaction point at PEP for two years and has shown no aging effects

  15. Measurement of deeply virtual Compton scattering using the ZEUS detector at HERA

    International Nuclear Information System (INIS)

    Grabowska-Bold, I.

    2004-08-01

    The cross sections for deeply virtual compton scattering in the reaction ep → e'γp' has been measured with the ZEUS detector at HERA using integrated luminosities of 95 pb -1 of e + p and 17 pb -1 of e - p collisions. Cross sections are presented as a function of the exchanged photon virtuality, Q 2 , and the centre-of-mass energy, W, of the γ * p system in the region 5 2 2 and 40 < W < 140 GeV. The obtained results are compared to QCD-based calculations. (orig.)

  16. Photoproduction of events with rapidity gaps between jets with ZEUS at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, P.D.

    2006-11-15

    Cross sections for the photoproduction of dijet events, where the two jets with the highest transverse energy are separated by a large gap in pseudorapidity, have been studied with the ZEUS detector using an integrated luminosity of 38.6 pb{sup -1}. Rapidity-gap events are defined in terms of the energy flow between the jets, such that the total summed transverse energy in this region is less than some value E{sup CUT}{sub T}. The data show a clear excess above the predictions of standard photoproduction models. Models which include color-singlet exchange are able to describe the data. (orig.)

  17. Data analysis of the ZEUS forward plug calorimeter beam test at CERN

    CERN Document Server

    Kasemann, M; Boettcher, S; Bohnet, I; Fernandez, J P; Goebel, F; Gottlicher, P; Gabareen, A; Garcia, G; Gendner, N; Graciani, R; Hauser, M; Horstmann, D; Inuzuka, M; Khein, L A; Lohr, B; Lewis, R; Lim, H; Lindemann, L; Markun, P; Martinez, M; Neumann, T; Park, I H; del Peso, J; Raach, H; Savin, A; Son, D; Tokushuku, K; Wolfle, S; Whitmore, J; Wick, K; Wolf, G; Yamashita, T; Yamazaki, Y

    2000-01-01

    Before installation in ZEUS the Forward Plug Colorimeter FPC was tested and calibrated using the X test b eam facility of the SPS accelerator at CERN This note summarizes setup and conditions of the test b eam measurements The energy calibration of the FPC using GeV electron and pion b eams as well as GeV muon data is describ ed in some detail The detector p erformance with pion and electron b eams is studied and the results of two monitoring systems using a Co source and an LED system are presented

  18. Precision calculation of processes used for luminosity measurement at the ZEUS experiment

    International Nuclear Information System (INIS)

    Haas, T.; Makarenko, V.

    2010-09-01

    The process pe ± → pe ± γ with the photon emitted along the electron beam axis is used for luminosity measurement at HERA. In this paper the process is calculated including one-loop QED radiative corrections. In the ZEUS experiment, both the electron and the photon can be detected. Therefore both photon and electron spectra with and without the γ-e coincidence are analyzed. We also calculate the process pe ± → pe ± l - l + which contributes to the background in the electron tagger. (orig.)

  19. Photoproduction of events with rapidity gaps between jets with ZEUS at HERA

    International Nuclear Information System (INIS)

    Ryan, P.D.

    2006-11-01

    Cross sections for the photoproduction of dijet events, where the two jets with the highest transverse energy are separated by a large gap in pseudorapidity, have been studied with the ZEUS detector using an integrated luminosity of 38.6 pb -1 . Rapidity-gap events are defined in terms of the energy flow between the jets, such that the total summed transverse energy in this region is less than some value E CUT T . The data show a clear excess above the predictions of standard photoproduction models. Models which include color-singlet exchange are able to describe the data. (orig.)

  20. Deep inelastic cross-section measurements at large y with the ZEUS detector at HERA

    International Nuclear Information System (INIS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.

    2014-04-01

    The reduced cross sections for e + p deep inelastic scattering have been measured with the ZEUS detector at HERA at three different centre-of-mass energies, 318, 251 and 225 GeV. The cross sections, measured double differentially in Bjorken x and the virtuality, Q 2 , were obtained in the region 0.13≤y≤0.75, where y denotes the inelasticity and 5≤Q 2 ≤110 GeV 2 . The proton structure functions F 2 and F L were extracted from the measured cross sections.

  1. Measruement of beauty production in DIS and F2bantib extraction at ZEUS

    International Nuclear Information System (INIS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.

    2010-04-01

    Beauty production in deep inelastic scattering with events in which a muon and a jet are observed in the final state has been measured with the ZEUS detector at HERA using an integrated luminosity of 114 pb -1 . The fraction of events with beauty quarks in the data was determined using the distribution of the transverse momentum of the muon relative to the jet. The cross section for beauty production was measured in the kinematic range of photon virtuality, Q 2 >2 GeV 2 , and inelasticity, 0.05 2 was extracted and is compared to theoretical predictions. (orig.)

  2. A Note on the 'Hellenic League against Persia' and the Sanctuary of Zeus at Nemea

    DEFF Research Database (Denmark)

    Nielsen, Thomas Heine

    2007-01-01

      The present note discusses why 'The Hellenic League against Persia' made no thank-offering to Zeus at Nemea after its defeat of Xerxes' invasion, even though it did make monumental thank-offerings at the three other great Panhellenic sanctuaries at Delphi, Isthmia and Olympia. It has been argued...... that Nemea was the least prestigious of the four great sanctuaries, and while this is probably true, two additional reasons may be adduced: (1) there was no tradition of celebrating martial victory at Nemea, and even if there had been (2) the sanctuary may have been tainted with medism on account...

  3. Locking mechanisms in degree-4 vertex origami structures

    Science.gov (United States)

    Fang, Hongbin; Li, Suyi; Xu, Jian; Wang, K. W.

    2016-04-01

    Origami has emerged as a potential tool for the design of mechanical metamaterials and metastructures whose novel properties originate from their crease patterns. Most of the attention in origami engineering has focused on the wellknown Miura-Ori, a folded tessellation that is flat-foldable for folded sheet and stacked blocks. This study advances the state of the art and expands the research field to investigate generic degree-4 vertex (4-vertex) origami, with a focus on facet-binding. In order to understand how facet-binding attributes to the mechanical properties of 4-vertex origami structures, geometries of the 4-vertex origami cells are analyzed and analytically expressed. Through repeating and stacking 4-vertex cells, origami sheets and stacked origami blocks can be constructed. Geometry analyses discover four mechanisms that will lead to the self-locking of 4-vertex origami cells, sheets, and stacked blocks: in-cell facet-binding, inlayer facet-binding, inter-layer facet binding, and in-layer and inter-layer facet-bindings. These mechanisms and the predicted self-locking phenomena are verified through 3D simulations and prototype experiments. Finally, this paper briefly introduces the unusual mechanical properties caused by the locking of 4-vertex origami structures. The research reported in this paper could foster a new breed of self-locking structures with various engineering applications.

  4. Exclusive production of J/ψ mesons in the ZEUS detector

    International Nuclear Information System (INIS)

    Tandler, J.

    2003-07-01

    Exclusive J/ψ production has been studied using the ZEUS detector at HERA. Two ranges of the photon virtuality, Q 2 2 and 0.15 2 2 are examined. The latter is defined by requiring the scattered electron to be detected in the Beam Pipe Calorimeter under low angles. The J/ψ mesons have been identified via the decay J/ψ→e + e - . The cross sections are measured as a function of the photon-proton centre-of-mass energy, W. The data used were taken during the 1999 and 2000 running periods, which yielded an integrated luminosity of 68.7 pb -1 . The measured W dependences are in agreement with each other and the values obtained in high-Q 2 (2 2 2 ) measurements. This leads to the conclusion that J/ψ production is a hard process for all Q 2 values and can be described with models based on perturbative QCD. Electron-pion separation of the ZEUS Transition Radiation Detector is measured. A method to combine TRD information and dE/dx measurements from the central drift chamber is developed and applied to the Q 2 2 J/ψ sample. (orig.)

  5. Archaeogeophysical Surveys on Mersin, Silifke, Uzuncaburç (Diokaisareia) Zeus Olbios Temple

    Science.gov (United States)

    Ahmet Yüksel, Fethi; Deniz, Hazel; Şahin, Hamdi

    2017-04-01

    The ancient city of Diocaesarea (Uzuncaburç), located 30 km north Silifke in Mersin, was a temple centre subjected to Olba in the Hellenistic period. It was declared as free city by Tiberius in the Early Imperial period and it flourished until the 5th century AD. During this period, a Thykhaion to the west of the city was built in the 1st century AD by Obrimos and his son Oppius from his wife Kyria, daughter of Leonidas. A theater was also erected in the co-reign of Marcus Aurelius and Lucius Verus and the city gate in the west of Diocaesarea was repaired under Arcadius and Honorius (396-408 AD). It was financed by the dux ad comes of Isauria, Leontios. In July 2011, archaeogeophysical measurements were made on the columns of the town of Zeus Olbios and on the peripteral Street of the city by magnetic methods. The purpose of these investigations is to determine the presence of architectural remains under the ground at the points specified. G-858 Cesium Gradiometer (G-858 Cesium Gradiometer) was used for magnetic measurement. These measurements were made on 38 pitches of 20 m length in Zeus Olbios temple on 13 creeks of 160 m length on the city's columned street. obtained sub-sensor, top sensor and gradient magnetic maps are created. Linear, angular locations with high susceptibilty were identified on magnetic maps. Keywords: Magnetic, Diokaisareia (Uzuncahurç), Archaeogeophysics, Archaeology, Cesium Gradiometer

  6. Measurement of the proton structure function at HERA using the ZEUS detector

    International Nuclear Information System (INIS)

    Bentvelsen, S.C.M.

    1994-01-01

    In May 1992, the HERA collider produced its first collisions between electrons and protons, at a center-of-mass energy of 295 GeV. The ZEUS experiment, one of the two main detectors at HERA, recorded 24.7 nb -1 of data in the fall of 1992. The analysis of this data, leading to an initial determination of the proton structure function F 2 in the kinematic domain accessible at HERA, is the main subject of this thesis. In the first chapter, a short review of inclusive deep-inelastic-scattering (DIS) is given. We also briefly present the status of pre-HERA fixed target DIS experiments. The second chapter offers a description of the HERA accelerator complex, the luminosity measurement and the ZEUS detector. Chapter three treats the reconstruction of x ans Q 2 from measured quantities. Chapter four describes the selection of the DIS data sample. Chapter five investigates various distributions of the DIS sample in comparison with the Monte Carlo predictions. The Monte Carlo distributions are given for extreme choices of the proton structure function parametrizations. In chapter six, we determine from the x and Q 2 distributions the proton structure function F 2 . A correction is made for the effect of the longitudinal structure function F L . The measured F 2 as a function of x is rising rapidly towards low values of x. (orig.)

  7. Tracking and vertexing for B physics at hadron accelerators

    International Nuclear Information System (INIS)

    Johnson, R.; Purohit, M.; Weidemann, A.W.

    1993-01-01

    In this note, the authors report on some of the activities of the Tracking and Vertexing Working Group of this Workshop. Track and vertex finding is essential to exploit the high production rate of B-mesons at hadron accelerators, both for triggering and analysis. Here, they review the tracking and vertex-finding systems of some of the major existing and proposed collider and fixed-target experiments at existing and future hadron accelerators, with a view towards their usefulness for B-physics. The capabilities of both general-purpose detectors and those of dedicated B-physics experiments are considered

  8. LHCb: Performance and Radiation Damage Effects in the LHCb Vertex Locator

    CERN Multimedia

    Carvalho Akiba, K

    2014-01-01

    LHCb is a dedicated experiment to study New Physics in the decays of heavy hadrons at the LHC. Heavy hadrons are identified through their flight distance in the Vertex Locator (VELO), hence the detector is critical for both the trigger and offline physics analyses. The VELO is the retractable silicon-strip detector surrounding the LHCb interaction point. It is located only 7 mm from the LHC beam during normal LHC operation, once moved into its closed position for each LHC fill when stable beams are obtained. During insertion the detector is centred around the LHC beam by the online reconstruction of the primary vertex position. Both VELO halves comprise 21 silicon micro-strip modules each. A module is made of two n-on-n 300 $\\mu$m thick half-disc sensors with R-measuring and $\\phi$-measuring micro-strip geometry, mounted on a carbon fibre support paddle. The minimum pitch is approximately 40 $\\mu$m. The detector is also equipped with the only n-on-p sensors operating at the LHC. The detectors are operated in ...

  9. Vertex Normals and Face Curvatures of Triangle Meshes

    KAUST Repository

    Sun, Xiang; Jiang, Caigui; Wallner, Johannes; Pottmann, Helmut

    2016-01-01

    This study contributes to the discrete differential geometry of triangle meshes, in combination with discrete line congruences associated with such meshes. In particular we discuss when a congruence defined by linear interpolation of vertex normals

  10. Graph Theory. 2. Vertex Descriptors and Graph Coloring

    Directory of Open Access Journals (Sweden)

    Lorentz JÄNTSCHI

    2002-12-01

    Full Text Available This original work presents the construction of a set of ten sequence matrices and their applications for ordering vertices in graphs. For every sequence matrix three ordering criteria are applied: lexicographic ordering, based on strings of numbers, corresponding to every vertex, extracted as rows from sequence matrices; ordering by the sum of path lengths from a given vertex; and ordering by the sum of paths, starting from a given vertex. We also examine a graph that has different orderings for the above criteria. We then proceed to demonstrate that every criterion induced its own partition of graph vertex. We propose the following theoretical result: both LAVS and LVDS criteria generate identical partitioning of vertices in any graph. Finally, a coloring of graph vertices according to introduced ordering criteria was proposed.

  11. Vertex function of an electron in a constant electromagnetic field

    International Nuclear Information System (INIS)

    Morozov, D.A.; Narozhnyj, N.B.; Ritus, V.I.

    1981-01-01

    The third order with respect to radiation field vertex function for an electron located in a constant crossed field of arbitrary intensity is determined. It is shown that radiative interaction smears out the Airy function which describes the intensity of the interaction between electrons and photons in an external field as a function of the nonconserving momentum component. The qualitative relation Vsup((3)) approximately αchisup(2/3)Vsup((1)) between the third and first order vertex functions is found for large values of the dynamic parameter chi=((eFp)sup(2))sup(1/2)msup(-2). It is also shown that radiative interaction does not alter the order of magnitude of the squared mass of the system transferred at the vertex. The vertex function satisfies the Ward identity modified by the external field [ru

  12. The NA50 segmented target and vertex recognition system

    International Nuclear Information System (INIS)

    Bellaiche, F.; Cheynis, B.; Contardo, D.; Drapier, O.; Grossiord, J.Y.; Guichard, A.; Haroutunian, R.; Jacquin, M.; Ohlsson-Malek, F.; Pizzi, J.R.

    1997-01-01

    The NA50 segmented target and vertex recognition system is described. The segmented target consists of 7 sub-targets of 1-2 mm thickness. The vertex recognition system used to determine the sub-target where an interaction has occured is based upon quartz elements which produce Cerenkov light when traversed by charged particles from the interaction. The geometrical arrangement of the quartz elements has been optimized for vertex recognition in 208 Pb-Pb collisions at 158 GeV/nucleon. A simple algorithm provides a vertex recognition efficiency of better than 85% for dimuon trigger events collected with a 1 mm sub-target set-up. A method for recognizing interactions of projectile fragments (nuclei and/or groups of nucleons) is presented. The segmented target allows a large target thickness which together with a high beam intensity (∼10 7 ions/s) enables high statistics measurements. (orig.)

  13. Vertex functions at finite momentum: Application to antiferromagnetic quantum criticality

    Science.gov (United States)

    Wölfle, Peter; Abrahams, Elihu

    2016-02-01

    We analyze the three-point vertex function that describes the coupling of fermionic particle-hole pairs in a metal to spin or charge fluctuations at nonzero momentum. We consider Ward identities, which connect two-particle vertex functions to the self-energy, in the framework of a Hubbard model. These are derived using conservation laws following from local symmetries. The generators considered are the spin density and particle density. It is shown that at certain antiferromagnetic critical points, where the quasiparticle effective mass is diverging, the vertex function describing the coupling of particle-hole pairs to the spin density Fourier component at the antiferromagnetic wave vector is also divergent. Then we give an explicit calculation of the irreducible vertex function for the case of three-dimensional antiferromagnetic fluctuations, and show that it is proportional to the diverging quasiparticle effective mass.

  14. Uncovering the triple omeron vertex from Wilson line formalism

    International Nuclear Information System (INIS)

    Chirilli, G. A.; Szymanowski, L.; Wallon, S.

    2011-01-01

    We compute the triple omeron vertex from the Wilson line formalism, including both planar and nonplanar contributions, and get perfect agreement with the result obtained in the Extended Generalized Logarithmic Approximation based on Reggeon calculus.

  15. Vertex Reconstruction in the ATLAS Experiment at the LHC

    CERN Document Server

    Bouhova-Thacker, E; The ATLAS collaboration; Kostyukhin, V; Liebig, W; Limper, M; Piacquadio, G; Lichard, P; Weiser, C; Wildauer, A

    2009-01-01

    In the harsh environment of the Large Hadron Collider at CERN (design luminosity of $10^{34}$ cm$^{-2}$ s$^{-1}$) efficient reconstruction of vertices is crucial for many physics analyses. Described in this paper are the strategies for vertex reconstruction used in the ATLAS experiment and their implementation in the software framework Athena. The algorithms for the reconstruction of primary and secondary vertices as well as for finding of photon conversions and vertex reconstruction in jets are described. A special emphasis is made on the vertex fitting with application of additional constraints. The implementation of mentioned algorithms follows a very modular design based on object-oriented C++ and use of abstract interfaces. The user-friendly concept allows event reconstruction and physics analyses to compare and optimize their choice among different vertex reconstruction strategies. The performance of implemented algorithms has been studied on a variety of Monte Carlo samples and results are presented.

  16. Discussion on the electronic problems of straw vertex detector

    International Nuclear Information System (INIS)

    Xi Deming

    1992-01-01

    The measurement of the characteristic time of the output waveform of straw vertex detector, the design of its high resolution and high counting rate readout system and the problems of the charge and time calibrations are discussed

  17. A new method for computing the quark-gluon vertex

    International Nuclear Information System (INIS)

    Aguilar, A C

    2015-01-01

    In this talk we present a new method for determining the nonperturbative quark-gluon vertex, which constitutes a crucial ingredient for a variety of theoretical and phenomenological studies. This new method relies heavily on the exact all-order relation connecting the conventional quark-gluon vertex with the corresponding vertex of the background field method, which is Abelian-like. The longitudinal part of this latter quantity is fixed using the standard gauge technique, whereas the transverse is estimated with the help of the so-called transverse Ward identities. This method allows the approximate determination of the nonperturbative behavior of all twelve form factors comprising the quark-gluon vertex, for arbitrary values of the momenta. Numerical results are presented for the form factors in three special kinematical configurations (soft gluon and quark symmetric limit, zero quark momentum), and compared with the corresponding lattice data. (paper)

  18. Fluctuations in two-dimensional six-vertex systems

    International Nuclear Information System (INIS)

    Youngblood, R.W.; Axe, J.D.; McCoy, B.M.

    1979-01-01

    The character of polarization correlations in six-vertex systems is discussed. With the aid of a connection between the 1-d Heisenberg--Ising chain and the six-vertex problem, existing results for the chain correlations are used to obtain information about long-wavelength polarization correlations in six-vertex models. These results are compared with a neutron scattering study of 2-d polarization correlations in the layered compound copper formate tetrahydrate. Because the six-vertex model is equivalent to a particular roughening model, these results also explicitly predict the critical behavior of that roughening model just above its roughening temperature. The results correspond to the predictions of Kosterlitz and Thouless for the phase transition in the 2-d Coulomb gas. 5 figures

  19. Ghost story. II. The midpoint ghost vertex

    International Nuclear Information System (INIS)

    Bonora, L; Maccaferri, C; Scherer Santos, R.J.; Tolla, D D

    2009-01-01

    We construct the ghost number 9 three strings vertex for OSFT in the natural normal ordering. We find two versions, one with a ghost insertion at z = i and a twist-conjugate one with insertion at z = -i. For this reason we call them midpoint vertices. We show that the relevant Neumann matrices commute among themselves and with the matrix G representing the operator K 1 . We analyze the spectrum of the latter and find that beside a continuous spectrum there is a (so far ignored) discrete one. We are able to write spectral formulas for all the Neumann matrices involved and clarify the important role of the integration contour over the continuous spectrum. We then pass to examine the (ghost) wedge states. We compute the discrete and continuous eigenvalues of the corresponding Neumann matrices and show that they satisfy the appropriate recursion relations. Using these results we show that the formulas for our vertices correctly define the star product in that, starting from the data of two ghost number 0 wedge states, they allow us to reconstruct a ghost number 3 state which is the expected wedge state with the ghost insertion at the midpoint, according to the star recursion relation.

  20. Vertex trigger implementation using shared memory technology

    CERN Document Server

    Müller, H

    1998-01-01

    The implementation of a 1 st level vertex trigger for LHC-B is particularly difficult due to the high ( 1 MHz ) input data rate. With ca. 350 silicon hits per event, both the R strips and Phi strips of the detectors produce a total of ca 2 Gbyte/s zero-suppressed da ta.1 note succeeds to the ideas to use R-phi coordinates for fast integer linefinding in programmable hardware, as described in LHB note 97-006. For an implementation we propose a FPGA preprocessing stage operating at 1 MHz with the benefit to substantially reduce the amount of data to be transmitted to the CPUs and to liberate a large fraction of CPU time. Interconnected via 4 Gbit/s SCI technol-ogy 2 , a shared memory system can be built which allows to perform data driven eventbuilding with, or without preprocessing. A fully data driven architecture between source modules and destination memories provides a highly reliable memory-to-memory transfer mechanism of very low latency. The eventbuilding is performed via associating events at the sourc...

  1. Dynamical Vertex Approximation for the Hubbard Model

    Science.gov (United States)

    Toschi, Alessandro

    A full understanding of correlated electron systems in the physically relevant situations of three and two dimensions represents a challenge for the contemporary condensed matter theory. However, in the last years considerable progress has been achieved by means of increasingly more powerful quantum many-body algorithms, applied to the basic model for correlated electrons, the Hubbard Hamiltonian. Here, I will review the physics emerging from studies performed with the dynamical vertex approximation, which includes diagrammatic corrections to the local description of the dynamical mean field theory (DMFT). In particular, I will first discuss the phase diagram in three dimensions with a special focus on the commensurate and incommensurate magnetic phases, their (quantum) critical properties, and the impact of fluctuations on electronic lifetimes and spectral functions. In two dimensions, the effects of non-local fluctuations beyond DMFT grow enormously, determining the appearance of a low-temperature insulating behavior for all values of the interaction in the unfrustrated model: Here the prototypical features of the Mott-Hubbard metal-insulator transition, as well as the existence of magnetically ordered phases, are completely overwhelmed by antiferromagnetic fluctuations of exponentially large extension, in accordance with the Mermin-Wagner theorem. Eventually, by a fluctuation diagnostics analysis of cluster DMFT self-energies, the same magnetic fluctuations are identified as responsible for the pseudogap regime in the holed-doped frustrated case, with important implications for the theoretical modeling of the cuprate physics.

  2. Performance of the LHCb Vertex Locator

    CERN Document Server

    Aaij, R.; Akiba, K.; Alexander, M.; Ali, S.; Appleby, R.B.; Artuso, M.; Bates, A.; Bay, A.; Behrendt, O.; Benton, J.; van Beuzekom, M.; Bjornstad, P.M.; Bogdanova, G.; Borghi, S.; Borgia, A.; Bowcock, T.J.V.; van den Brand, J.; Brown, H.; Buytaert, J.; Callot, O.; Carroll, J.; Casse, G.; Collins, P.; De Capua, S.; Doets, M.; Donleavy, S.; Dossett, D.; Dumps, R.; Eckstein, D.; Eklund, L.; Farinelli, C.; Farry, S.; Ferro-Luzzi, M.; Frei, R.; Garofoli, J.; Gersabeck, M.; Gershon, T.; Gong, A.; Gong, H.; Gordon, H.; Haefeli, G.; Harrison, J.; Heijne, V.; Hennessy, K.; Hulsbergen, W.; Huse, T.; Hutchcroft, D.; Jaeger, A.; Jalocha, P.; Jans, E.; John, M.; Keaveney, J.; Ketel, T.; Korolev, M.; Kraan, M.; Lastovicka, T.; Lafferty, G.; Latham, T.; Lefeuvre, G.; Leflat, A.; Liles, M.; van Lysebetten, A.; MacGregor, G.; Marinho, F.; McNulty, R.; Merkin, M.; Moran, D.; Mountain, R.; Mous, I.; Mylroie-Smith, J.; Needham, M.; Nikitin, N.; Noor, A.; Oblakowska-Mucha, A.; Papadelis, A.; Pappagallo, M.; Parkes, C.; Patel, G.D.; Rakotomiaramanana, B.; Redford, S.; Reid, M.; Rinnert, K.; Rodrigues, E.; Saavedra, A.F.; Schiller, M.; Schneider, O.; Shears, T.; Silva Coutinho, R.; Smith, N.A.; Szumlak, T.; Thomas, C.; van Tilburg, J.; Tobin, M.; Velthuis, J.; Verlaat, B.; Viret, S.; Volkov, V.; Wallace, C.; Wang, J.; Webber, A.; Whitehead, M.; Zverev, E.

    2014-01-01

    The Vertex Locator (VELO) is a silicon microstrip detector that surrounds the proton-proton interaction region in the LHCb experiment. The performance of the detector during the first years of its physics operation is reviewed. The system is operated in vacuum, uses a bi-phase CO2 cooling system, and the sensors are moved to 7 mm from the LHC beam for physics data taking. The performance and stability of these characteristic features of the detector are described, and details of the material budget are given. The calibration of the timing and the data processing algorithms that are implemented in FPGAs are described. The system performance is fully characterised. The sensors have a signal to noise ratio of approximately 20 and a best hit resolution of 4 microns is achieved at the optimal track angle. The typical detector occupancy for minimum bias events in standard operating conditions in 2011 is around 0.5%, and the detector has less than 1% of faulty strips. The proximity of the detector to the beam means ...

  3. Functional imaging of sleep vertex sharp transients.

    Science.gov (United States)

    Stern, John M; Caporro, Matteo; Haneef, Zulfi; Yeh, Hsiang J; Buttinelli, Carla; Lenartowicz, Agatha; Mumford, Jeanette A; Parvizi, Josef; Poldrack, Russell A

    2011-07-01

    The vertex sharp transient (VST) is an electroencephalographic (EEG) discharge that is an early marker of non-REM sleep. It has been recognized since the beginning of sleep physiology research, but its source and function remain mostly unexplained. We investigated VST generation using functional MRI (fMRI). Simultaneous EEG and fMRI were recorded from seven individuals in drowsiness and light sleep. VST occurrences on EEG were modeled with fMRI using an impulse function convolved with a hemodynamic response function to identify cerebral regions correlating to the VSTs. A resulting statistical image was thresholded at Z>2.3. Two hundred VSTs were identified. Significantly increased signal was present bilaterally in medial central, lateral precentral, posterior superior temporal, and medial occipital cortex. No regions of decreased signal were present. The regions are consistent with electrophysiologic evidence from animal models and functional imaging of human sleep, but the results are specific to VSTs. The regions principally encompass the primary sensorimotor cortical regions for vision, hearing, and touch. The results depict a network comprising the presumed VST generator and its associated regions. The associated regions functional similarity for primary sensation suggests a role for VSTs in sensory experience during sleep. Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  4. Mirror of the refined topological vertex from a matrix model

    CERN Document Server

    Eynard, B

    2011-01-01

    We find an explicit matrix model computing the refined topological vertex, starting from its representation in terms of plane partitions. We then find the spectral curve of that matrix model, and thus the mirror symmetry of the refined vertex. With the same method we also find a matrix model for the strip geometry, and we find its mirror curve. The fact that there is a matrix model shows that the refined topological string amplitudes also satisfy the remodeling the B-model construction.

  5. Performance of the ATLAS primary vertex reconstruction algorithms

    CERN Document Server

    Zhang, Matt

    2017-01-01

    The reconstruction of primary vertices in the busy, high pile up environment of the LHC is a challenging task. The challenges and novel methods developed by the ATLAS experiment to reconstruct vertices in such environments will be presented. Such advances in vertex seeding include methods taken from medical imagining, which allow for reconstruction of very nearby vertices will be highlighted. The performance of the current vertexing algorithms using early Run-2 data will be presented and compared to results from simulation.

  6. The quintic interaction vertex in light-cone gravity

    International Nuclear Information System (INIS)

    Ananth, Sudarshan

    2008-01-01

    We consider pure gravity in light-cone gauge and derive the complete quintic interaction vertex. Up to quartic order, the Kawai-Lewellen-Tye (KLT) relations can be made manifest at the level of the Einstein-Hilbert Lagrangian. The quintic interaction vertex represents an essential first step in further extending the off-shell validity of the KLT relations to higher order vertices

  7. Tracking and vertexing with the ATLAS detector at the LHC

    International Nuclear Information System (INIS)

    Hirsch, F.

    2011-01-01

    The Inner Detector of the ATLAS experiment at the Large Hadron Collider at CERN contains three tracking systems: The silicon Pixel Detector, the Silicon Microstrip Tracker and the Transition Radiation Tracker. In combination these detectors provide excellent track and vertex reconstruction efficiencies and resolutions. This paper describes studies which show the performance of track and vertex reconstruction on data collected at 7 TeV center-of-mass energy.

  8. Stochastic higher spin six vertex model and Macdonald measures

    Science.gov (United States)

    Borodin, Alexei

    2018-02-01

    We prove an identity that relates the q-Laplace transform of the height function of a (higher spin inhomogeneous) stochastic six vertex model in a quadrant on one side and a multiplicative functional of a Macdonald measure on the other. The identity is used to prove the GUE Tracy-Widom asymptotics for two instances of the stochastic six vertex model via asymptotic analysis of the corresponding Schur measures.

  9. The vertex detector for the Lepton/Photon collaboration

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, J.P.; Boissevain, J.G.; Fox, D.; Hecke, H. van; Jacak, B.V.; Kapustinsky, J.S.; Leitch, M.J.; McGaughey, P.L.; Moss, J.M.; Sondheim, W.E. [Los Alamos National Lab., NM (United States)

    1991-12-31

    The conceptual design of the vertex detector for the Lepton/Photon Collaboration at RHIC is described, including simulations of its expected performance. The design consists of two con- centric layers of single-sided Si strips. The expected performance as a multiplicity detector and in measuring the pseudo-rapidity ({nu}) distribution is discussed as well as the expected vertex finding efficiency and accuracy. Various options which could be used to reduce the cost of the detector are also discussed.

  10. Construction of vertex operators using operator formalism techniques

    International Nuclear Information System (INIS)

    Gato, B.; Massachusetts Inst. of Tech., Cambridge

    1989-01-01

    We derive vertex operators in oscillator form as an application of the conserved charges method developed by Vafa for the operator formalism in higher genus Riemann surfaces. This construction proves to be clear, direct and valid for the bosonic and fermionic strings as wells as for twisted strings on orbifolds. We discuss the method and construct vertex operators for the bosonic string moving on Z N orbifolds and for the fermionic string in the NSR formulation. (orig.)

  11. The vertex detector for the Lepton/Photon Collaboration

    International Nuclear Information System (INIS)

    Sullivan, J.P.; Boissevain, J.G.; Fox, D.; van Hecke, H.; Jacak, B.V.; Kapustinsky, J.S.; Leitch, M.J.; McGaughey, P.L.; Moss, J.M.; Sondheim, W.E.

    1991-01-01

    The conceptual design of the vertex detector for the Lepton/Photon Collaboration at RHIC is described, including simulations of its expected performance. The design consists of two concentric layers of single-sided Si strips. The expected performance as a multiplicity detector and in measuring the pseudo-rapidity η distribution is discussed as well as the expected vertex finding efficiency and accuracy. Various options which could be used to reduce the cost of the detector are also discussed

  12. Vertex Reconstruction at STAR: Overview and Performance Evaluation

    Science.gov (United States)

    Smirnov, D.; Lauret, J.; Perevoztchikov, V.; Van Buren, G.; Webb, J.

    2017-10-01

    The STAR experiment at the Relativistic Heavy Ion Collider (RHIC) has a rich physics program ranging from studies of the Quark Gluon Plasma to the exploration of the spin structure of the proton. Many measurements carried out by the STAR collaboration rely on the efficient reconstruction and precise knowledge of the position of the primary-interaction vertex. Throughout the years two main vertex finders have been predominantly utilized in event reconstruction by the experiment: MinutVF and PPV with their application domains focusing on heavy ion and proton-proton events respectively. In this work we give a brief overview and discuss recent improvements to the vertex finding algorithms implemented in the STAR software library. In our studies we focus on the finding efficiency and the quality of the reconstructed primary vertex. We examine the effect of an additional constraint, imposed by an independent measurement of the beam line position, when it is applied during the fit. We evaluate the significance of the improved primary vertex resolution on identification of the secondary decay vertices occurring inside the beam pipe. Finally, we present a method and its software implementation developed to measure the performance of the primary vertex reconstruction algorithms.

  13. Smarandachely Adjacent-Vertex-Distinguishing Proper Edge Chromatic Number of Cm∨Kn

    OpenAIRE

    Shunqin Liu

    2016-01-01

    According to different conditions, researchers have defined a great deal of coloring problems and the corresponding chromatic numbers. Such as, adjacent-vertex-distinguishing total chromatic number, adjacent-vertex-distinguishing proper edge chromatic number, smarandachely-adjacent-vertex-distinguishing proper edge chromatic number, smarandachely-adjacent-vertex-distinguishing proper total chromatic number. And we focus on the smarandachely adjacent-vertex-distinguishing proper edge chromatic...

  14. Construction of the Zeus forward/rear calorimeter modules at NIKHEF

    Science.gov (United States)

    Blankers, R.; Engelen, J.; Geerinck, H.; Homma, J.; Hunck, P.; Dekoning, N.; Kooijman, P.; Korporaal, A.; Loos, R.; Straver, J.

    1990-07-01

    The design and assembly procedure of the FCAL/RCAL (Forward (in proton direction) Calorimeter/Rear (in electron direction) Calorimeter) of the Zeus detector to study electron proton interactions at Desy, Hamburg (Germany, F.R.) are detailed. The main components of the modules are described: steel C-frame which provides the overall mechanical module structure; a stack of depleted uranium plates and scintillator plates; wavelength shifter material, mounted in cassettes for the readout of the scintillator light; stainless steel straps which compress the stack and fix it to the C-frame. Finite element techniques for module force calculations are outlined. The module assembly and transport and calibration tools are described.

  15. Construction and beam test of the ZEUS forward and rear calorimeter

    International Nuclear Information System (INIS)

    Andresen, A.; Kroeger, W.; Krueger, J.; Ros, E.; Tsurugai, T.; Woeniger, T.; Bargende, A.; Crittenden, J.A.; Hartmann, J.; Hilger, E.; Kraemer, M.; Prange, K.; Schneider, H.L.; Barreiro, F.; Cases, G.; Hervas, L.; Behrens, U.; Dannemann, A.; Holm, U.; Kammerlocher, H.; Krebs, B.; Wick, K.; Caldwell, A.; Ritz, S.; Sippach, W.; Dawson, J.; Dierks, K.; Drews, G.; Fuertjes, A.; Hagge, L.; Klanner, R.; Koetz, U.; Rohde, M.; Schulz, W.; Selonke, F.; Vogel, W.; Youngman, C.; Fawcett, H.; Frisken, W.; Hasell, D.; Gilkinson, D.; Hanna, D.; Mitchell, J.; Patel, P.; Hamatsu, R.; Kitamura, S.; Hasegawa, T.; Hazumi, M.; Ishii, T.; Kasai, S.; Kuze, M.; Tokushuku, K.; Yamada, S.; Romanowski, T.

    1991-04-01

    The forward and rear calorimeters of the ZEUS experiment are made of 48 modules with maximum active dimensions of 4.6 m height, 0.2 m width, 7 λ depth and maximum weigth of 12 t. It consists of 1 X 0 uranium plates interleaved with plastic scintillator tiles read out via wavelength shifters and photomultipliers. The mechanical construction, the achieved tolerances as well as the optical and electronics readout are described. Ten of these modules have been tested with electrons, hadrons and muons in the momentum range 15-100 GeV/c. Results von resolution, uniformity and calibration are presented. Our main result is the achieved calibration accuracy of about 1% obtained by using the signal from the uranium radioactivity. (orig.)

  16. Studies on the prototype of the transition-radiation detector for the Zeus experiment

    International Nuclear Information System (INIS)

    Munde, A.

    1991-04-01

    The Zeus detector is currently being built for HERA at Hamburg. One part of the inner detector is the transition radiation detector (TRD). It will identify single electrons inside hadronic jets of deep inelastic ep-collisions. To test the chamber performance and to improve mechanical tools, a prototype of the smallest detector modul (TRD-1) was built. The gasgain of this prototype was measured under several high voltage conditions. The gasgain is about 1.5x10 3 up to 8x10 3 in Argon/Methane 90/10. To test the function of this prototype, the test beam facility at the Bonn 2.5 GeV electron synchrotron was used. The same relative amplification was measured by comparing the beam results with those obtained with a Fe 55 -source. (orig.) [de

  17. Construction and test of the analog electronics for the planar drift chambers of the ZEUS detector

    International Nuclear Information System (INIS)

    Meyer, J.

    1990-03-01

    The front-end-electronics for the planar drift chambers. FTD/RTD, of the ZEUS detector, developed by Siegen University, has been tested in their performance together with a FTD testcell. This cell was operated under new high voltage conditions and showed a gas gain of G ≅ 1x10 4 . The electronics, consisting of a preamplifier, a 45 m signal cable and a postamplifier with the ability of puls shaping, had to be matched to the dynamic input range of the FADS's. This led to a completely new design of the postamplifier. Signal crosstalk in the drift cell can distort the original puls shape and possibly leads to a wrong trace reconstruction. Measurements of the crosstalk showed a 10% effect, that can be reduced by a passive crosstalk compensation to less than 5%. (orig.) [de

  18. Calibration of the electromagnetic part of the ZEUS calorimeter with electrons

    International Nuclear Information System (INIS)

    Bargende, A.

    1991-05-01

    Ten modules of the Uranium-Scintillator-Calorimeter for ZEUS were exposed to the X5-beam at CERN. The momentum of the beam is determined with an accuracy of better than 1.1%. From measurements with electrons in the energy range of 10 to 110 GeV we obtain the following results. The energy resolution is found to be better than 18% / √ E/GeV. A worse resolution measured in the HACO-towers is explained by averaging effects over the beam size. The uranium noise provides an intercalibration of the calorimeter sections within 1.1% for electron signals in the FCAL (1.5% in RCAL). The linearity of the FCAL is better than 0.5%. Nonlinearities of 2% in the RCAL are mainly caused by the photomultipliers. (orig.) [de

  19. The optimization of the electrostatic field inside the ZEUS forward drift chambers: Calculations and measurements

    International Nuclear Information System (INIS)

    Dobberstein, M.P.; Krawczyk, F.; Schaefer-Jotter, M.

    1990-11-01

    The electrostatic field inside small drift cells shows in general edge effects which are not negligible. These are usually corrected by field shaping wires or strips. The operating voltages of the field shaping electrodes have to be adjusted to maximize the field homogeneity. We present the underlying ideas of such an optimization procedure for the cells of the ZEUS forward drift chambers. Using the finite difference code PROFI, the optimization can be performed automatically by a multiple solution of the Poisson equation. An experimental verification of the optimal voltages was carried out measuring the gas amplifications at the six sense wires. Modifications of the drift cell geometry were necessary for calibration measurements with a laser beam. This caused additional distortions of the electrostatic field. Their influence was calculated using the MAFIA code, which allows to include open boundary conditions. (orig.)

  20. Calculation of track and vertex errors for detector design studies

    International Nuclear Information System (INIS)

    Harr, R.

    1995-01-01

    The Kalman Filter technique has come into wide use for charged track reconstruction in high-energy physics experiments. It is also well suited for detector design studies, allowing for the efficient estimation of optimal track covariance matrices without the need of a hit level Monte Carlo simulation. Although much has been published about the Kalman filter equations, there is a lack of previous literature explaining how to implement the equations. In this paper, the operators necessary to implement the Kalman filter equations for two common detector configurations are worked out: a central detector in a uniform solenoidal magnetic field, and a fixed-target detector with no magnetic field in the region of the interactions. With the track covariance matrices in hand, vertex and invariant mass errors are readily calculable. These quantities are particularly interesting for evaluating experiments designed to study weakly decaying particles which give rise to displaced vertices. The optimal vertex errors are obtained via a constrained vertex fit. Solutions are presented to the constrained vertex problem with and without kinematic constraints. Invariant mass errors are obtained via propagation of errors; the use of vertex constrained track parameters is discussed. Many of the derivations are new or previously unpublished

  1. A covariant representation of the Ball–Chiu vertex

    International Nuclear Information System (INIS)

    Ahmadiniaz, Naser; Schubert, Christian

    2013-01-01

    In nonabelian gauge theory the three-gluon vertex function contains important structural information, in particular on infrared divergences, and is also an essential ingredient in the Schwinger–Dyson equations. Much effort has gone into analyzing its general structure, and at the one-loop level also a number of explicit computations have been done, using various approaches. Here we use the string-inspired formalism to unify the calculations of the scalar, spinor and gluon loop contributions to the one-loop vertex, leading to an extremely compact representation in all cases. The vertex is computed fully off-shell and in dimensionally continued form, so that it can be used as a building block for higher-loop calculations. We find that the Bern–Kosower loop replacement rules, originally derived for the on-shell case, hold off-shell as well. We explain the relation of the structure of this representation to the low-energy effective action, and establish the precise connection with the standard Ball–Chiu decomposition of the vertex. This allows us also to predict that the vanishing of the completely antisymmetric coefficient function S of this decomposition is not a one-loop accident, but persists at higher-loop orders. The sum rule found by Binger and Brodsky, which leads to the vanishing of the one-loop vertex in N=4 SYM theory, in the present approach relates to worldline supersymmetry

  2. A covariant representation of the Ball–Chiu vertex

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadiniaz, Naser, E-mail: naser@ifm.umich.mx [Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Apdo. Postal 2-82, C.P. 58040, Morelia, Michoacán (Mexico); Dipartimento di Fisica, Università di Bologna and INFN, Sezione di Bologna, Via Irnerio 46, I-40126 Bologna (Italy); Schubert, Christian, E-mail: schubert@ifm.umich.mx [Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Apdo. Postal 2-82, C.P. 58040, Morelia, Michoacán (Mexico); Dipartimento di Fisica, Università di Bologna and INFN, Sezione di Bologna, Via Irnerio 46, I-40126 Bologna (Italy); Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut, Mühlenberg 1, D-14476 Potsdam (Germany)

    2013-04-21

    In nonabelian gauge theory the three-gluon vertex function contains important structural information, in particular on infrared divergences, and is also an essential ingredient in the Schwinger–Dyson equations. Much effort has gone into analyzing its general structure, and at the one-loop level also a number of explicit computations have been done, using various approaches. Here we use the string-inspired formalism to unify the calculations of the scalar, spinor and gluon loop contributions to the one-loop vertex, leading to an extremely compact representation in all cases. The vertex is computed fully off-shell and in dimensionally continued form, so that it can be used as a building block for higher-loop calculations. We find that the Bern–Kosower loop replacement rules, originally derived for the on-shell case, hold off-shell as well. We explain the relation of the structure of this representation to the low-energy effective action, and establish the precise connection with the standard Ball–Chiu decomposition of the vertex. This allows us also to predict that the vanishing of the completely antisymmetric coefficient function S of this decomposition is not a one-loop accident, but persists at higher-loop orders. The sum rule found by Binger and Brodsky, which leads to the vanishing of the one-loop vertex in N=4 SYM theory, in the present approach relates to worldline supersymmetry.

  3. Performance, Radiation Damage Effects and Upgrade of the LHCb Vertex Locator

    CERN Document Server

    De Capua, S

    2013-01-01

    LHCb is a dedicated experiment to study New Physics in the decays of heavy hadrons at the Large Hadron Collider (LHC). Heavy hadrons are identified through their flight distance in the VELO, the retractable silicon-strip vertex detector surrounding the LHCb interaction point at only 7 mm from the beam during normal LHC operation. Both VELO halves comprise 21 silicon micro-strip modules each. A module is made of two n-on-n 300 µm thick half-disc sensors with R- and phi-measuring geometry, mounted on a carbon fibre support paddle. The minimum pitch is approximately 40 µm. The detector is also equipped with the only n-on-p module operating at the LHC. The performance of the VELO in its three years of successful operation during the LHC physics runs will be presented. Highlights will include alignment, cluster finding efficiency, single hit resolution, and impact parameter and vertex resolutions. The VELO module sensors receive a large and non-uniform radiation dose having inner and outer radii of only 7 and 42...

  4. Track and Vertex Reconstruction in the ATLAS Experiment

    CERN Document Server

    Lacuesta, V; The ATLAS collaboration

    2012-01-01

    The track and vertex reconstruction algorithms of the ATLAS Inner Detector have demonstrated excellent performance in the early data from the LHC. However, the rapidly increas- ing number of interactions per bunch crossing introduces new challenges both in computational aspects and physics performance. The combination of both silicon and gas based detectors provides high precision impact parameter and momentum measurement of charged particles, with high efficiency and small fake rate. Vertex reconstruction is used to identify with high efficiency the hard scattering process and to measure the amount of pile-up interactions, both aspects are cru- cial for many physics analyses. The performance of track and vertex reconstruction efficiency and resolution achieved in the 2011 and 2012 data-taking period are presented.

  5. Track and Vertex Reconstruction in the ATLAS Experiment

    CERN Document Server

    Lacuesta, V; The ATLAS collaboration

    2012-01-01

    The track and vertex reconstruction algorithms of the ATLAS Inner Detector have demonstrated excellent performance in the early data from the LHC. However, the rapidly increas- ing number of interactions per bunch crossing introduces new challenges both in computational aspects and physics performance. The combination of both silicon and gas based detectors pro- vides high precision impact parameter and momentum measurement of charged particles, with high efficiency and small fake rate. Vertex reconstruction is used to identify with high efficiency the hard scattering process and to measure the amount of pile-up interactions, both aspects are cru- cial for many physics analyses. The performance of track and vertex reconstruction efficiency and resolution achieved in the 2011 and 2012 data-taking period are presented.

  6. Plethystic vertex operators and boson-fermion correspondences

    International Nuclear Information System (INIS)

    Fauser, Bertfried; Jarvis, Peter D; King, Ronald C

    2016-01-01

    We study the algebraic properties of plethystic vertex operators, introduced in (2010 J. Phys. A: Math. Theor. 43 405202), underlying the structure of symmetric functions associated with certain generalized universal character rings of subgroups of the general linear group, defined to stabilize tensors of Young symmetry type characterized by a partition of arbitrary shape π . Here we establish an extension of the well-known boson-fermion correspondence involving Schur functions and their associated (Bernstein) vertex operators: for each π , the modes generated by the plethystic vertex operators and their suitably constructed duals, satisfy the anticommutation relations of a complex Clifford algebra. The combinatorial manipulations underlying the results involve exchange identities exploiting the Hopf-algebraic structure of certain symmetric function series and their plethysms. (paper)

  7. Measurement of Rb Using a Vertex Mass Tag

    International Nuclear Information System (INIS)

    Steiner, R.; Benvenuti, A.C.; Coller, J.A.; Hedges, S.J.; Johnson, A.S.; Shank, J.T.; Whitaker, J.S.; Allen, N.J.; Cotton, R.; Dervan, P.J.; Hasan, A.; McKemey, A.K.; Watts, S.J.; Caldwell, D.O.; Lu, A.; Yellin, S.J.; Cavalli-Sforza, M.; Coyne, D.G.; Fernandez, J.P.; Liu, X.; Reinertsen, P.L.; Schalk, T.; Schumm, B.A.; DOliveira, A.; Johnson, R.A.; Meadows, B.T.; Nussbaum, M.; Dima, M.; Harton, J.L.; Smy, M.B.; Staengle, H.; Wilson, R.J.; Baranko, G.; Fahey, S.; Fan, C.; Krishna, N.M.; Lauber, J.A.; Nauenberg, U.; Wagner, D.L.; Bazarko, A.O.; Bolton, T.; Rowson, P.C.; Shaevitz, M.H.; Camanzi, B.; Mazzucato, E.; Piemontese, L.; Calcaterra, A.; De Sangro, R.; Peruzzi, I.; Piccolo, M.; Eisenstein, B.I.; Gladding, G.; Karliner, I.; Shapiro, G.; Steiner, H.; Bardon, O.; Burrows, P.N.; Busza, W.; Cowan, R.F.; Dong, D.N.; Fero, M.J.; Gonzalez, S.; Kendall, H.W.; Lath, A.; Lia, V.; Osborne, L.S.; Quigley, J.; Taylor, F.E.; Torrence, E.; Verdier, R.; Williams, D.C.

    1998-01-01

    We report a new measurement of R b =Γ Z 0 →bbar b /Γ Z 0 →hadrons using a double tag technique, where the b hemisphere selection is based on the reconstructed mass of the B hadron decay vertex. The measurement was performed using a sample of 130x10 3 hadronic Z 0 events, collected with the SLD detector at SLC. The method utilizes the 3D vertexing abilities of the CCD pixel vertex detector and the small stable SLC beams to obtain a high b -tagging efficiency and purity. We obtain R b =0.2142±0.0034(stat) ±0.0015(syst)±0.0002( R c ) . copyright 1998 The American Physical Society

  8. Track and vertex reconstruction in the ATLAS experiment

    International Nuclear Information System (INIS)

    Lacuesta, V

    2013-01-01

    The track and vertex reconstruction algorithms of the ATLAS Inner Detector have demonstrated excellent performance in the early data from the LHC. However, the rapidly increasing number of interactions per bunch crossing introduces new challenges both in computational aspects and physics performance. The combination of both silicon and gas based detectors provides high precision impact parameter and momentum measurement of charged particles, with high efficiency and small fake rate. Vertex reconstruction is used to identify with high efficiency the hard scattering process and to measure the amount of pile-up interactions, both aspects are crucial for many physics analyses. The performance of track and vertex reconstruction efficiency and resolution achieved in the 2011 and 2012 data-taking period are presented.

  9. Plethystic vertex operators and boson-fermion correspondences

    Science.gov (United States)

    Fauser, Bertfried; Jarvis, Peter D.; King, Ronald C.

    2016-10-01

    We study the algebraic properties of plethystic vertex operators, introduced in (2010 J. Phys. A: Math. Theor. 43 405202), underlying the structure of symmetric functions associated with certain generalized universal character rings of subgroups of the general linear group, defined to stabilize tensors of Young symmetry type characterized by a partition of arbitrary shape π. Here we establish an extension of the well-known boson-fermion correspondence involving Schur functions and their associated (Bernstein) vertex operators: for each π, the modes generated by the plethystic vertex operators and their suitably constructed duals, satisfy the anticommutation relations of a complex Clifford algebra. The combinatorial manipulations underlying the results involve exchange identities exploiting the Hopf-algebraic structure of certain symmetric function series and their plethysms.

  10. A two-Transputer VME module for data acquisition and on-line event selection in ZEUS

    International Nuclear Information System (INIS)

    Boterenbrood, H.; Goble, S.; Jong, S.J. de; Kieft, G.; Lugt, H.J. van der; Uijterwaal, H.A.J.R.; Vermeulen, J.C.; Waard, A. de; Wiggers, L.W.

    1993-01-01

    For the ZEUS experiment at the HERA e-p collider in Hamburg a versatile and fast VME-based processor module has been developed at NIKHEF-H. The single-slot wide VME module contains two INMOS T800 Transputers, each with private memory, and a triple-port memory (TPM), accessible to both Transputers. Both Transputers have access to the VME bus, while an external master can also access the TPM directly. The VME accesses proceed typically with 10 Mbyte/s. Three application-specific integrated circuits (ASICs) handle the internal and external Transputer interfacing. The module combines the VME environment with the parallel processing and link-oriented environment of the Transputer. Over 200 modules are used in the data acquisition and event selection systems of ZEUS. (orig.)

  11. Propagation of epithermal neutrons in the empty mesh of the EDF3 reactor. Application of Zeus IV

    International Nuclear Information System (INIS)

    Brisbois, Jacques; Sonnet, Alain; Rafalovitch, Armand

    1969-10-01

    The authors report the verification of the Zeus 4 Monte Carlo code by applying it to an actual example of neutron propagation in a large enclosure, the empty mesh of the EDF3 reactor, supplied through the box holes (for the passage of heat transfer fluid ducts). This enclosure is represented by 105 parallelepipedic meshes in which are placed 4 plane and square sources of same cross section as the holes, and emitting inwards in cos θ. Source intensity is determined by flow rate measurements during tests in the air, interpreted by a Zeus-based calculation and channel power measurements during a 387 MW level operation. The presence of ducts is taken into account by applying a global attenuation coefficient to the sources. Calculation and experiment results agree very well in view of geometry complexity [fr

  12. High speed digital TDC for D0 vertex reconstruction

    International Nuclear Information System (INIS)

    Gao Guosheng; Partridge, R.

    1992-01-01

    A high speed digital TDC has been built as part of the Level 0 trigger for the D0 experiment at Fermilab. The digital TDC is used to make a fast determination of the primary vertex position by timing the arrival time of beam jets detected in the Level 0 counters. The vertex position is then used by the Level 1 trigger to determine the proper sinθ weighting factors for calculation transverse energies. Commercial GaAs integrated circuits are used in the digital TDC to obtain a time resolution of σ t == 226 ps

  13. Preliminary studies for the LHCb vertex detector vacuum system

    CERN Document Server

    Doets, M; Van Bakel, N; Van den Brand, J F J; van den Brand, Jo

    2000-01-01

    We lay down some general considerations which will serve as a starting point for design studies of a realistic LHCb vertex detector vacuum system. Based on these considerations, we propose a design strategy and identify issues to be further studied. In particular we try to outline some boundary conditions imposed by LHC and LHCb on the vacuum system. We discuss two possibilities for the LHCb vertex detector vacuum system. The preferred strategy uses a differentially pumped vacuum system with the silicon detectors separated from the beam line vacuum. Some estimations on static vacuum pressures and gas flows are presented.

  14. Vertex-Detector R&D for CLIC

    OpenAIRE

    Dannheim, Dominik

    2013-01-01

    A detector concept based on hybrid planar pixel-detector technology is under development for the CLIC vertex detector. It comprises fast, low-power and small-pitch readout ASICs implemented in 65 nm CMOS technology (CLICpix) coupled to ultra-thin sensors via low-mass interconnects. The power dissipation of the readout chips is reduced by means of power pulsing, allowing for a cooling system based on forced gas flow. In this paper the CLIC vertex-detector requirements are reviewed and the curr...

  15. RAVE-a Detector-independent vertex reconstruction toolkit

    International Nuclear Information System (INIS)

    Waltenberger, Wolfgang; Mitaroff, Winfried; Moser, Fabian

    2007-01-01

    A detector-independent toolkit for vertex reconstruction (RAVE) is being developed, along with a standalone framework (VERTIGO) for testing, analyzing and debugging. The core algorithms represent state of the art for geometric vertex finding and fitting by both linear (Kalman filter) and robust estimation methods. Main design goals are ease of use, flexibility for embedding into existing software frameworks, extensibility, and openness. The implementation is based on modern object-oriented techniques, is coded in C++ with interfaces for Java and Python, and follows an open-source approach. A beta release is available

  16. The RAVE/VERTIGO vertex reconstruction toolkit and framework

    Science.gov (United States)

    Waltenberger, W.; Mitaroff, W.; Moser, F.; Pflugfelder, B.; Riedel, H. V.

    2008-07-01

    A detector-independent toolkit for vertex reconstruction (RAVE1) is being developed, along with a standalone framework (VERTIGO2) for testing, analyzing and debugging. The core algorithms represent state-of-the-art for geometric vertex finding and fitting by both linear (Kalman filter) and robust estimation methods. Main design goals are ease of use, flexibility for embedding into existing software frameworks, extensibility, and openness. The implementation is based on modern object-oriented techniques, is coded in C++ with interfaces for Java and Python, and follows an open-source approach. A beta release is available.

  17. RAVE-a Detector-independent vertex reconstruction toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Waltenberger, Wolfgang [Institute of High Energy Physics, Austrian Academy of Sciences A-1050 Vienna (Austria)], E-mail: walten@hephy.oeaw.ac.at; Mitaroff, Winfried; Moser, Fabian [Institute of High Energy Physics, Austrian Academy of Sciences A-1050 Vienna (Austria)

    2007-10-21

    A detector-independent toolkit for vertex reconstruction (RAVE) is being developed, along with a standalone framework (VERTIGO) for testing, analyzing and debugging. The core algorithms represent state of the art for geometric vertex finding and fitting by both linear (Kalman filter) and robust estimation methods. Main design goals are ease of use, flexibility for embedding into existing software frameworks, extensibility, and openness. The implementation is based on modern object-oriented techniques, is coded in C++ with interfaces for Java and Python, and follows an open-source approach. A beta release is available.

  18. The RAVE/VERTIGO vertex reconstruction toolkit and framework

    Energy Technology Data Exchange (ETDEWEB)

    Waltenberger, W; Mitaroff, W; Moser, F; Pflugfelder, B; Riedel, H V [Austrian Academy of Sciences, Institute of High Energy Physics, A-1050 Vienna (Austria)], E-mail: walten@hephy.oeaw.ac.at

    2008-07-15

    A detector-independent toolkit for vertex reconstruction (RAVE{sup 1}) is being developed, along with a standalone framework (VERTIGO{sup 2}) for testing, analyzing and debugging. The core algorithms represent state-of-the-art for geometric vertex finding and fitting by both linear (Kalman filter) and robust estimation methods. Main design goals are ease of use, flexibility for embedding into existing software frameworks, extensibility, and openness. The implementation is based on modern object-oriented techniques, is coded in C++ with interfaces for Java and Python, and follows an open-source approach. A beta release is available.

  19. Z H η vertex in the simplest little Higgs model

    Science.gov (United States)

    He, Shi-Ping; Mao, Ying-nan; Zhang, Chen; Zhu, Shou-hua

    2018-04-01

    The issue of deriving Z H η vertex in the simplest little Higgs (SLH) model is revisited. Special attention is paid to the treatment of noncanonically-normalized scalar kinetic matrix and vector-scalar two-point transitions. We elucidate a general procedure to diagonalize a general vector-scalar system in gauge theories and apply it to the case of SLH. The resultant Z H η vertex is found to be different from those which have already existed in the literature for a long time. We also present an understanding of this issue from an effective field theory viewpoint.

  20. Simulations of silicon vertex tracker for star experiment at RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Odyniec, G.; Cebra, D.; Christie, W.; Naudet, C.; Schroeder, L.; Wilson, W. [Lawrence Berkeley Lab., CA (United States); Liko, D. [Institut fur Hochenenergiephysik, Vienna, (Austria); Cramer, J.; Prindle, D.; Trainor, T. [Univ. of Washington, Seattle (United States); Braithwaite, W. [Univ. of Arkansas, Little Rock (United States)

    1991-12-31

    The first computer simulations to optimize the Silicon Vertex Tracker (SVT) designed for the STAR experiment at RHIC are presented. The physics goals and the expected complexity of the events at RHIC dictate the design of a tracking system for the STAR experiment. The proposed tracking system will consist of a silicon vertex tracker (SVT) to locate the primary interaction and secondary decay vertices and to improve the momentum resolution, and a time projection chamber (TPC), positioned inside a solenoidal magnet, for continuous tracking.

  1. Electromagnetic form factors and vertex constants for 6Li

    International Nuclear Information System (INIS)

    Blokhintsev, L.D.; Shvarts, I.A.

    1977-01-01

    It has been assumed that the main contribution to the rapidly changing part of the charge form factor of 6 Li provides the amplitude of the triangle diagram containing virtual lines of deuteron and α particle. The vertex constant G 2 for the 6 Li→α+d decay is expressed through the nuclear charge radii for 6 Li, d, and α. Taking into account coulomb interaction in the vertex of the 6 Li→α+d reaction increases G 2 by about a factor of two. The account of virtuality of a deuteron cluster also leads to an increase in G 2

  2. Exploitation of secondary vertex information at the CDF detector. Final report, 1991--1994

    International Nuclear Information System (INIS)

    Amidei, D.

    1995-01-01

    In the proposal for this work, submitted in November 1990, the author described the application of silicon micro-vertex tracking to hadron collider physics, and outlined a plan of involvement in the first such application, at the CDF Detector, studying p anti p collisions at √s = 1.8 TeV at the Fermilab Tevatron. The proposal included discussion on the use of silicon tracking in B physics measurements, and also some speculation on the ability of silicon tracking to aid in identification of the top quark. In the five years since this proposal, the author has played a significant role in the installation and commissioning of the first such silicon tracking device at a hadron collider, and the utilization of this device in the discovery of the top quark and the study of B production mechanisms. This paper is a summary of this work

  3. 3D sensors and micro-fabricated detector systems

    International Nuclear Information System (INIS)

    Da Vià, Cinzia

    2014-01-01

    Micro-systems based on the Micro Electro Mechanical Systems (MEMS) technology have been used in miniaturized low power and low mass smart structures in medicine, biology and space applications. Recently similar features found their way inside high energy physics with applications in vertex detectors for high-luminosity LHC Upgrades, with 3D sensors, 3D integration and efficient power management using silicon micro-channel cooling. This paper reports on the state of this development

  4. On the local vertex antimagic total coloring of some families tree

    Science.gov (United States)

    Febriani Putri, Desi; Dafik; Hesti Agustin, Ika; Alfarisi, Ridho

    2018-04-01

    Let G(V, E) be a graph of vertex set V and edge set E. Local vertex antimagic total coloring developed from local edge and local vertex antimagic coloring of graph. Local vertex antimagic total coloring is defined f:V(G)\\cup E(G)\\to \\{1,2,3,\\ldots,|V(G)|+|E(G)|\\} if for any two adjacent vertices v 1 and v 2, w({v}1)\

  5. Performance-Optimization Studies for the CLIC Vertex Detector

    CERN Document Server

    AUTHOR|(CDS)2085406; Roloff, Philipp

    The Compact Linear Collider (CLIC) is a mutli-TeV linear e+e- collider currently under development at CERN. In the post-LHC era, CLIC will allow to explore a great number of searches for New Physics such as the precise measurements of the Higgs boson. In this master thesis, we mainly focus on the development and the improvement of the vertex detector. The vertex detector requires excellent spatial resolution, low mass, geometrical coverage down to low polar angles, high rate readout for the sensors and new cooling technologies for heat removal. Considering such requirements, the CLIC vertex detector technology is far more advanced in comparison to the technologies currently used in particle physics. This project consists of two main parts. In the first part, we study the vertex detector and optimize its geometry for the use of airflow cooling techniques and also for flavor tagging. In the second part, we implement a decoder which can respect the timing constraints for the CLICpix chip, a silicon pixel detect...

  6. Conservation laws, vertex corrections, and screening in Raman spectroscopy

    Science.gov (United States)

    Maiti, Saurabh; Chubukov, Andrey V.; Hirschfeld, P. J.

    2017-07-01

    We present a microscopic theory for the Raman response of a clean multiband superconductor, with emphasis on the effects of vertex corrections and long-range Coulomb interaction. The measured Raman intensity, R (Ω ) , is proportional to the imaginary part of the fully renormalized particle-hole correlator with Raman form factors γ (k ⃗) . In a BCS superconductor, a bare Raman bubble is nonzero for any γ (k ⃗) and diverges at Ω =2 Δmax , where Δmax is the largest gap along the Fermi surface. However, for γ (k ⃗) = constant, the full R (Ω ) is expected to vanish due to particle number conservation. It was sometimes stated that this vanishing is due to the singular screening by long-range Coulomb interaction. In our general approach, we show diagrammatically that this vanishing actually holds due to vertex corrections from the same short-range interaction that gives rise to superconductivity. We further argue that long-range Coulomb interaction does not affect the Raman signal for any γ (k ⃗) . We argue that vertex corrections eliminate the divergence at 2 Δmax . We also argue that vertex corrections give rise to sharp peaks in R (Ω ) at Ω <2 Δmin (the minimum gap along the Fermi surface), when Ω coincides with the frequency of one of the collective modes in a superconductor, e.g., Leggett and Bardasis-Schrieffer modes in the particle-particle channel, and an excitonic mode in the particle-hole channel.

  7. SVT: an online silicon vertex tracker for the CDF upgrade

    International Nuclear Information System (INIS)

    Bardi, A.; Belforte, S.; Berryhill, J.

    1997-07-01

    The SVT is an online tracker for the CDF upgrade which will reconstruct 2D tracks using information from the Silicon VerteX detector (SVXII) and Central Outer Tracker (COT). The precision measurement of the track impact parameter will then be used to select and record large samples of B hadrons. We discuss the overall architecture, algorithms, and hardware implementation of the system

  8. Fast simulation and topological vertex finding in JAVA

    International Nuclear Information System (INIS)

    Walkowiak, Wolfgang

    2001-01-01

    An overview of the fast Monte Carlo simulation for NLC detector studies as currently provided in the Java Analysis Studio environment is presented. Special emphasis is given to the simulation of tracks. In addition, the SLD collaboration's topological vertex finding algorithm (ZVTOP) has been implemented in the Java Analysis Studio framework

  9. Random matrices and the six-vertex model

    CERN Document Server

    Bleher, Pavel

    2013-01-01

    This book provides a detailed description of the Riemann-Hilbert approach (RH approach) to the asymptotic analysis of both continuous and discrete orthogonal polynomials, and applications to random matrix models as well as to the six-vertex model. The RH approach was an important ingredient in the proofs of universality in unitary matrix models. This book gives an introduction to the unitary matrix models and discusses bulk and edge universality. The six-vertex model is an exactly solvable two-dimensional model in statistical physics, and thanks to the Izergin-Korepin formula for the model with domain wall boundary conditions, its partition function matches that of a unitary matrix model with nonpolynomial interaction. The authors introduce in this book the six-vertex model and include a proof of the Izergin-Korepin formula. Using the RH approach, they explicitly calculate the leading and subleading terms in the thermodynamic asymptotic behavior of the partition function of the six-vertex model with domain wa...

  10. Self-locking degree-4 vertex origami structures.

    Science.gov (United States)

    Fang, Hongbin; Li, Suyi; Wang, K W

    2016-11-01

    A generic degree-4 vertex (4-vertex) origami possesses one continuous degree-of-freedom for rigid folding, and this folding process can be stopped when two of its facets bind together. Such facet-binding will induce self-locking so that the overall structure stays at a pre-specified configuration without additional locking elements or actuators. Self-locking offers many promising properties, such as programmable deformation ranges and piecewise stiffness jumps, that could significantly advance many adaptive structural systems. However, despite its excellent potential, the origami self-locking features have not been well studied, understood, and used. To advance the state of the art, this research conducts a comprehensive investigation on the principles of achieving and harnessing self-locking in 4-vertex origami structures. Especially, for the first time, this study expands the 4-vertex structure construction from single-component to dual-component designs and investigates their self-locking behaviours. By exploiting various tessellation designs, this research discovers that the dual-component designs offer the origami structures with extraordinary attributes that the single-component structures do not have, which include the existence of flat-folded locking planes, programmable locking points and deformability. Finally, proof-of-concept experiments investigate how self-locking can effectively induce piecewise stiffness jumps. The results of this research provide new scientific knowledge and a systematic framework for the design, analysis and utilization of self-locking origami structures for many potential engineering applications.

  11. The role of geometry in 4-vertex origami mechanics

    Science.gov (United States)

    Waitukaitis, Scott; Dieleman, Peter; van Hecke, Martin

    Origami offers an interesting design platform metamaterials because it strongly couples mechanics with geometry. Even so, most research carried out so far has been limited to one or two particular patterns. I will discuss the full geometrical space of the most common origami building block, the 4-vertex, and show how exotic geometries can have dramatic effects on the mechanics.

  12. Multipole expansion of vertex functions in an arbitrary frame

    International Nuclear Information System (INIS)

    Daumens, Michel

    1977-01-01

    Vertex functions are expanded on the bases of tensor spherical harmonics and tensor multipoles. The coefficients of the expansions are rotational invariant form factors. The relations with those defined in particular frames by Durand, De Celles and Marr, and by De Rafael are exhibited. Finally multipolar form factors are built which are irreducible under pure Lorentz transformations [fr

  13. Tripartite connection condition for a quantum graph vertex

    Czech Academy of Sciences Publication Activity Database

    Cheon, T.; Exner, Pavel; Turek, Ondřej

    2010-01-01

    Roč. 375, č. 2 (2010), s. 113-118 ISSN 0375-9601 R&D Projects: GA MŠk LC06002 Institutional research plan: CEZ:AV0Z10480505 Keywords : Schrodinger operator * Singular vertex * Boundary conditions Subject RIV: BA - General Mathematics Impact factor: 1.963, year: 2010

  14. Tests of track segment and vertex finding with neural networks

    International Nuclear Information System (INIS)

    Denby, B.; Lessner, E.; Lindsey, C.S.

    1990-04-01

    Feed forward neural networks have been trained, using back-propagation, to find the slopes of simulated track segments in a straw chamber and to find the vertex of tracks from both simulated and real events in a more conventional drift chamber geometry. Network architectures, training, and performance are presented. 12 refs., 7 figs

  15. Network Unfolding Map by Vertex-Edge Dynamics Modeling.

    Science.gov (United States)

    Verri, Filipe Alves Neto; Urio, Paulo Roberto; Zhao, Liang

    2018-02-01

    The emergence of collective dynamics in neural networks is a mechanism of the animal and human brain for information processing. In this paper, we develop a computational technique using distributed processing elements in a complex network, which are called particles, to solve semisupervised learning problems. Three actions govern the particles' dynamics: generation, walking, and absorption. Labeled vertices generate new particles that compete against rival particles for edge domination. Active particles randomly walk in the network until they are absorbed by either a rival vertex or an edge currently dominated by rival particles. The result from the model evolution consists of sets of edges arranged by the label dominance. Each set tends to form a connected subnetwork to represent a data class. Although the intrinsic dynamics of the model is a stochastic one, we prove that there exists a deterministic version with largely reduced computational complexity; specifically, with linear growth. Furthermore, the edge domination process corresponds to an unfolding map in such way that edges "stretch" and "shrink" according to the vertex-edge dynamics. Consequently, the unfolding effect summarizes the relevant relationships between vertices and the uncovered data classes. The proposed model captures important details of connectivity patterns over the vertex-edge dynamics evolution, in contrast to the previous approaches, which focused on only vertex or only edge dynamics. Computer simulations reveal that the new model can identify nonlinear features in both real and artificial data, including boundaries between distinct classes and overlapping structures of data.

  16. Recent developments in high precision vertex chambers at SLAC

    International Nuclear Information System (INIS)

    Rust, D.R.

    1984-04-01

    Three detectors MARK II, MAC, AND HRS are using or planning small drift chambers placed as close as possible to the interaction print at PEP. There is also a program of development for a gaseous vertex detector for MARK II at SLC. All these programs are reviewed. 13 references

  17. Performance of the CDF Silicon VerteX detector

    International Nuclear Information System (INIS)

    Schneider, O.

    1992-11-01

    The current status of the online and offline performance of the CDF Silicon VerteX detector is presented. So far, at low radiation dose, the device delivers good quality data. After the latest alignment using collision data, a spatial resolution of 13 pm is achieved in the transverse plane, demonstrating that CDF has a powerful tool to detect b decay vertices

  18. Status on the Zeus lightning network in Brazil and its application to the electrical sector of COELCE - the Energy Company from Ceara state

    Energy Technology Data Exchange (ETDEWEB)

    Morales Rodriguez, Carlos Augusto [Universidade de Sao Paulo (USP), SP (Brazil)], E-mail: morales@model.iag.usp.br; Sales, Francisco; Pinheiro, Francisco Geraldo [Universidade Estadual do Ceara (UECE), CE (Brazil)], E-mail: fsales@uece.br; Camara, Keyla Sampaio [Companhia de Energetica do Estado do Ceara (COELCE), Fortaleza, CE (Brazil)], Emails: keyla@coelce.com.br, fgmpinheiro@uece.br; Anagnostou, Emmanouil E. [University of Connecticut, Storrs, CT (United States)], E-mail: manos@engr.uconn.edu

    2007-07-01

    This paper presents the deployment and new perspectives of the ZEUS VLF long range lightning monitoring network that has been established in Brazil after the support of the Research and Development Program of the 'Companhia Energetica do Ceara-(COELCE)'. The ZEUS network measures radio noise emitted by lightning that propagates through the ionosphere-earth surface waveguide up to thousands of kilometers. Two new VLF antennas have been installed in Fortaleza (Ceara) and Cachoeira Paulista (Sao Paulo) Brazil in the first semester of 2006 and were integrated with the 4 sensor installed in Africa and one in the Caribbean. Based on this new configuration, ZEUS is continuing measuring lightning discharges over South and North America, the Atlantic Ocean and Africa. Preliminary validation analysis using the data from the Brazilian Lightning Detection Network (RINDAT), National Lightning Detection Network (NLDN) of USA, and Lightning Imaging Sensor (LIS) on board the Tropical Rainfall Measuring Mission were employed to retrieve the location accuracy during the period of August through November of 2006. The location accuracy is based on coincident timing matches been the sferics measurements observed by ZEUS against the measurements of RINDAT, NLDN and LIS. Based on this new ZEUS configuration, the preliminary validation shows that ZEUS has location accuracy between 10-50 km over Brazil, 5-25 km in Africa, 70-100 km over the southern USA, and 5-25 km in the Atlantic Ocean. The measurements from August through November of 2006 show that the main lightning activity is located in the Western Amazon, Western and Central Africa, Central America, Colombia, Florida and Caribbean regions, which agrees with the lightning maps derived with LIS for the same time period. Finally, since ZEUS is been employed by COELCE, some lightning and thunderstorm products are been developed to help the improvement of their system over the states of Ceara, for example: lightning

  19. The design of the ZEUS tracking trigger and studies of b quark fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Silvester, I M

    1989-01-01

    This thesis consists of two parts, describing two very different aspects of experimental elementary particle physics. The first part describes, in detail, the design and estimated performance of a hardware track finding trigger processor. This processor is being built as part of the trigger for the ZEUS experiment, one of the two experiments being built to take data at the HERA electron-proton collider, currently under construction at the DESY laboratories in Hamburg. By using information from the main tracking chamber, the CTD, to reject data from events taking place outside the interaction region, this processor should be able to reduce the event rate from a beam crossing rate of 10{sup 6} s{sup -1} to approximately 9500 s{sup -1}. Used in conjunction with a trigger processor processing calorimeter data it should be able to achieve the desired first level trigger rate of 1 kHz. The second part describes two measurements of the fragmentation variable z for b quarks, made using a b enriched sample of 381 jets taken from the 31000 hadronic events with a centre of mass energy of 35 GeV observed with the TASSO detector during 1986. These measurements, obtained from the mean charged multiplicity and the rapidity distribution, have largely independent systematic uncertainties. The values obtained for (z{sub b}) were combined to give a value of 0.87{+-}0.02{+-}0.04. (author).

  20. Measurements of the exclusive production of a real photon with the ZEUS detector at HERA II

    International Nuclear Information System (INIS)

    Santamarta Martinez, R.

    2007-06-01

    The study of exclusive processes is one of the most promising tools to obtain information on the nucleon via generalized parton distributions. The simplest of these reactions is the Deeply Virtual Compton Scattering process in which a real photon is produced via diffractive exchange. Using the interference term between Deeply Virtual Compton Scattering and the Bethe-Heitler processes it is possible to extract the generalized parton distributions. The measurement presented in this thesis is a study of Deeply Virtual Compton Scattering and Bethe-Heitler processes recorder with the ZEUS detector. The data analyzed were taken with HERA II in the years 2003 to 2005, corresponding to an integrated luminosity of 41 pb -1 for e + p and 136 pb -1 for e - p scattering data. The cross section of the elastic Bethe-Heitler process measured in the kinematic region 230 2 2 and vertical stroke t vertical stroke 2 is presented. The feasibility of measurement of the Deeply Virtual Compton Scattering process is also reported. (orig.)

  1. The magnetic field for the ZEUS central detector - analysis and correction of the field measurement

    International Nuclear Information System (INIS)

    Mengel, S.

    1992-06-01

    The magnetic field in the central tracking region of the ZEUS-detector - a facility to investigate highly energetic electron-proton-collisions at the HERA-collider at DESY Hamburg - is generated by a superconducting coil and reaches 18 kG (1.8 T). Some of the tracking devices particularly the drift chambers in the proton forward and rear direction (FTD1-3 and RTD) are not fully contained within the coil and therefore situated in a highly inhomogeneous magnetic field: The radial component B r is up to 6.6 kG, maximum gradients are found to be 300 G/cm for δB r /δr. Evaluating the space drifttime relation necessitates a detailed knowledge of the magnetic field. To reach this goal we analysed the field measurements and corrected them for systematic errors. The corrected data were compared with the field calculations (TOSCA-maps). Measurements and calculations are confirmed by studying consistency with Maxwell's equations. The accuracy reached is better than 100 G throughout the forward and central drift chambers (FTD1-3, CTD) and better than 150 G in the RTD. (orig.) [de

  2. ZEUS: a cophasing sensor based on the Zernike phase contrast method

    Science.gov (United States)

    Dohlen, Kjetil; Langlois, Maud; Lanzoni, Patrick; Mazzanti, Silvio; Vigan, Arthur; Montoya, Luzma; Hernandez, Elvio; Reyes, Marcos; Surdej, Isabel; Yaitskova, Natalya

    2006-06-01

    We describe the ZEUS phasing camera for future extremely large telescopes (ELTs) based on the Zernike phase contrast method. A prototype instrument is under construction for implementation in the Active Phasing Experiment (APE), a VLT test bed scheduled for operation in 2007. The paper describes theoretical aspects of the method and its experimental validation, as well as the instrumental implementation for APE. Aspects of its implementation in an ELT are also discussed. While the classical Zernike method uses a phase mask with diameter approximately equal to the Airy disk, we employ a mask the size of the seeing disk. This allows us to overcome the problems related to atmospheric turbulence, whose low spatial frequency phase errors are much larger than the co-phasing errors to be measured. The thickness (OPD) of the mask can be set to lambda/4 - as in the classical case - for maximum signal strength, but for initial phasing where phase errors are much larger than the sensor's linear range (+/-lambda/4), a thinner mask produces a cleaner signal more easily exploitable, leaving the signal analysis more robust. A multi wavelength approach is implemented in order to extend the capture range of the sensor, and the ultimate precision is reached using an iterative approach. End-to-end simulations indicating an achievable precision within the required precision will be shown.

  3. First determination of the e/π separation efficiency of the ZEUS transition radiation detector

    International Nuclear Information System (INIS)

    Mengel, S.

    1995-12-01

    The Transition Radiation Detector of the ZEUS experiment at DESY is one of its main instruments for electron identification. It started to operate partly in 1993 and for the first time with its four modules in 1994. One of its main features is a Time Expansion Chamber to detect the transition radiation of electrons together with the ionisation energy loss of the particle tracks. The first data taken under realistic environmental conditions served as tool to find appropriate running conditions and procedures for data treatment. The main aim however was to show that the detector is sensitive to electrons and to evaluate its rejection power. This analysis describes the on-line and off-line data processing required to exploit the information contained in the raw data. Concepts for detector cross channel calibration and signal recombination are presented. The effect of different running conditions is discussed. To determine the rejection power a data selection was performed extracting electrons and hadrons using all means except the TRD. The response of the TRD to these data samples was compared and a clear sensitivity for electrons was found. Using different likelihood methods values for separation power are derived. The hadron suppression obtained at 90% electron efficiency is - for momenta from 1 to 3 GeV/c - between 27% to 10%, which is already close to the design/test chamber results of 9% to 1.7%. As a projection for close-to-optimum running conditions a hadron suppression from 12% to 2% was obtained. (orig.)

  4. Search for excited leptons in ep scattering at HERA using the ZEUS detector

    International Nuclear Information System (INIS)

    Weber, A.

    2002-03-01

    A search for heavy excited electrons and neutrinos has been performed with the ZEUS detector at HERA. The ep scattering data used were taken at a centre-of-mass energy of 318 GeV in the years 1998-2000. Excited electrons have been searched for in e - p and e + p collisions corresponding to integrated luminosities of 16.7 pb -1 and 66.1 pb -1 , respectively. The decay channels e * → eγ, e * → νW → νqq' and e * → eZ → eqq have been considered. Excited neutrinos have been sought in the e - p data set via the decay channels ν * → νγ, ν * → eW → eqq' and ν * → νZ → νqq. The event selection has been performed employing both fixed cuts and a probability-based method as alternatives, with the latter yielding better overall performance. No evidence for an e * or ν * signal is observed in any of the channels analysed. Upper limits (95% confidence level) as a function of the excited-lepton mass have been set on the cross section times the branching ratio, σ x BR, and on the coupling over the compositeness scale, f/Λ. In many cases, these limits extend up to higher masses and are more stringent than the existing ones. (orig.)

  5. Charm production in ep collisions with the ZEUS detector at HERA

    International Nuclear Information System (INIS)

    Bargende, A.

    1995-02-01

    The production of charmed mesons in ep collisions has been studied with the 1993 data from the ZEUS detector at HERA. Charm quarks are produced by the photoproduction process of photon-gluon fusion. Analysing a data sample corresponding to an integrated luminosity of 486 nb -1 D*(2010) ± mesons have been found in two decay channels, D* + →D 0 π + →(K - π + )π + (+c.c.) and D* + →D 0 π + →((K S 0 →π + π - )π + π - )π + . Clear signals in the mass difference ΔM=M(D*)-M(D 0 ) as well as in the M(D 0 ) distribution are found. The ep cross section for D* ± production with Q 2 2 and 115 -9 +4 ) nb in the kinematic region {p T (D*)≥1.7 GeV, vertical stroke η(D*)vertical stroke -0.21 +0.35 μb) at √(s)=296 GeV and 115 -2.9 6.1 ) μb in the range 115 -8.4 +13.1 ) μb in the range 205< W<275 GeV. (orig.)

  6. Fine pitch and low material readout bus in the Silicon Pixel Vertex Tracker for the PHENIX Vertex Tracker upgrade

    International Nuclear Information System (INIS)

    Fujiwara, Kohei

    2010-01-01

    The construction of the Silicon Pixel Detector is starting in spring 2009 as project of the RHIC-PHENIX Silicon Vertex Tracker (VTX) upgrade at the Brookhaven National Laboratory. For the construction, we have developed a fine pitch and low material readout bus as the backbone parts of the VTX. In this article, we report the development and production of the readout bus.

  7. Operator Product Formulas in the Algebraic Approach of the Refined Topological Vertex

    International Nuclear Information System (INIS)

    Cai Li-Qiang; Wang Li-Fang; Wu Ke; Yang Jie

    2013-01-01

    The refined topological vertex of Iqbal—Kozçaz—Vafa has been investigated from the viewpoint of the quantum algebra of type W 1+∞ by Awata, Feigin, and Shiraishi. They introduced the trivalent intertwining operator Φ which is normal ordered along with some prefactors. We manage to establish formulas from the infinite operator product of the vertex operators and the generalized ones to restore this prefactor, and obtain an explicit formula for the vertex realization of the topological vertex as well as the refined topological vertex

  8. Identification of electrons in the ZEUS hadron-electron separator with neural networks

    International Nuclear Information System (INIS)

    Carstens, J.O.

    1994-10-01

    An electron finder for the ZEUS experiment was constructed, which is specialized to electrons in the momentum range 0.5 to 3.0 GeV/c. For the first time this electron finder connects the informations of the calorimeter with those of the hadron-electron separator (HES). For this purpose the electron finder was equipped with a neural network. The electron finder reached on a data set of photoproduction events with conversion electrons an efficiency and discriminance of E=(62.9±2.2±0.6)% and D=(91.4±0.8±1.1)%. From these two quantities it can be calculated that the electron finder the ratio electrons to background increases by the factoe E/(1-D)=7.4 (Signal amplification). For the comparison: A neural net, to which only calorimeter informations have been made available, reached at the same efficiency a signal amplification of 2.4. A simple cut in the variable HES-signal reaches a signal amplification of 6.3. Hints were given, how training data sets with electrons and hadrons of higher energies can be obtained. With such data sets the working range of the electron finder can be without problems extended to higher momenta. As preparation for the construction of the electron finder an introduction to the foundations of the mathematics and the application of neural networks was given. By means of examples different methods for the convergence improvement have been tested. Numerous representations mediate illustrative imaginations on the mathematical process of the training of neural networks

  9. Charm photoproduction using electron taggers with the Zeus detector at HERA

    International Nuclear Information System (INIS)

    Aghuzumtsyan, G.

    2006-07-01

    Charm production has been studied at a centre-of-mass energy of √(s)=318 GeV in the ZEUS experiment at the electron-proton collider HERA. The data from the years 1998-2000 are used. Photoproduction is identified by reconstructing the D * (2010) meson via the decay chain D *+ →K - π + π + (+c.c.) and by selecting the scattered electron in one of the dedicated electron taggers located 44m and 35m away from the interaction point. The total visible cross section and differential cross sections as a function of p T (D * ), η(D * ) and W were measured in the restricted phase space: -1.0 * ) T (D * )>1.5 GeV, 80 GeV 2 2 in case of the 44m tagger sample, and -1.5 * ) T (D * )>2.0 GeV, 200 GeV 2 2 in case of the 35m tagger sample. Next-to-leading-order QCD predictions were calculated in the same kinematic region as the data. The comparison of the theoretical predictions with the data shows good agreement within the theoretical uncertainties. Total charm cross sections were calculated by extrapolating the visible cross sections in the limited (p T (D * ), η(D * )) phase space to the full kinematic region. The measurements with the 35m tagger overlap with previous untagged data while the 44m tagger data are used to study a new intermediate region 80 GeV 44m <120 GeV between fixed target and and the other HERA measurements. The comparison of the NLO QCD predictions with the data shows good agreement. (orig.)

  10. The Zeus Mission Study — An application of automated collaborative design

    Science.gov (United States)

    Doyotte, Romain; Love, Stanley G.; Peterson, Craig E.

    1999-11-01

    The purpose of the Zeus Mission Study was threefold. As an element of a graduate course in spacecraft system engineering, its purpose was primarily educational — to allow the students to apply their knowledge in a real mission study. The second purpose was to investigate the feasibility of applying advanced technology (the power antenna and solar electric propulsion concepts) to a challenging mission. Finally, the study allowed evaluation of the benefits of using quality-oriented techniques (Quality Function Deployment (QFD) and Taguchi Methods) for a mission study. To encourage innovation, several constraints were placed on the study from the onset. While the primary goal was to place at least one lander on Europa, the additional constraint of no nuclear power sources posed an additional challenge, particularly when coupled with the mass constraints imposed by using a Delta II class launch vehicle. In spite of these limitations, the team was able to develop a mission and spacecraft design capable of carrying three simple, lightweight, yet capable landers. The science return will more than adequately meet the science goals established QFD was used to determine the optimal choice of instrumentation. The lander design was selected from several competing lander concepts, including rovers. The carrier design was largely dictated by the needs of the propulsion system required to support the mission, although the development of a Project Trades Model (PTM) in software allowed for rapid recalculation of key system parameters as changes were made. Finally, Taguchi Methods (Design of Experiments) were used in conjunction with the PTM allowing for some limited optimization of design features.

  11. A Vertex and Tracking Detector System for CLIC

    CERN Document Server

    AUTHOR|(SzGeCERN)718101

    2017-01-01

    The physics aims at the proposed future CLIC high-energy linear $e^+e^−$ collider pose challenging demands on the performance of the detector system. In particular the vertex and tracking detectors have to combine precision measurements with robustness against the expected high rates of beam-induced backgrounds. The requirements include ultra-low mass, facilitated by power pulsing and air cooling in the vertex-detector region, small cell sizes and precision hit timing at the few-ns level. A detector concept meeting these requirements has been developed and an integrated R&D program addressing the challenges is progressing in the areas of ultra-thin sensors and readout ASICs, interconnect technology, mechanical integration and cooling.

  12. Vertex detectors: The state of the art and future prospects

    Energy Technology Data Exchange (ETDEWEB)

    Damerell, C.J.S. [Rutherford Appleton Laboratory, Didcot (United Kingdom)

    1997-01-01

    We review the current status of vertex detectors (tracking microscopes for the recognition of charm and bottom particle decays). The reasons why silicon has become the dominant detector medium are explained. Energy loss mechanisms are reviewed, as well as the physics and technology of semiconductor devices, emphasizing the areas of most relevance for detectors. The main design options (microstrips and pixel devices, both CCD`s and APS`s) are discussed, as well as the issue of radiation damage, which probably implies the need to change to detector media beyond silicon for some vertexing applications. Finally, the evolution of key performance parameters over the past 15 years is reviewed, and an attempt is made to extrapolate to the likely performance of detectors working at the energy frontier ten years from now.

  13. OPAL Central Detector (Including vertex, jet and Z chambers)

    CERN Multimedia

    OPAL was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. OPAL's central tracking system consists of (in order of increasing radius) a silicon microvertex detector, a vertex detector, a jet chamber, and z-chambers. All the tracking detectors work by observing the ionization of atoms by charged particles passing by: when the atoms are ionized, electrons are knocked out of their atomic orbitals, and are then able to move freely in the detector. These ionization electrons are detected in the different parts of the tracking system. (This piece includes the vertex, jet and Z chambers) In the picture above, the central detector is the piece being removed to the right.

  14. Worldline calculation of the three-gluon vertex

    International Nuclear Information System (INIS)

    Ahmadiniaz, N.; Schubert, C.

    2012-01-01

    The three-gluon vertex is a basic object of interest in nonabelian gauge theory. At the one-loop level, it has been calculated and analyzed by a number of authors. Here we use the worldline formalism to unify the calculations of the scalar, spinor and gluon loop contributions to the one-loop vertex, leading to an extremely compact representation in terms of field strength tensors. We verify its equivalence with previously obtained representations, and explain the relation of its structure to the low-energy effective action. The sum rule found by Binger and Brodsky for the scalar, spinor and gluon loop contributions in the present approach relates to worldline supersymmetry.

  15. The secondary vertex finding algorithm with the ATLAS detector

    CERN Document Server

    Heer, Sebastian; The ATLAS collaboration

    2017-01-01

    A high performance identification of jets, produced via fragmentation of bottom quarks, is crucial for the ATLAS physics program. These jets can be identified by exploiting the presence of cascade decay vertices from bottom hadrons. A general vertex-finding algorithm is introduced and its ap- plication to the search for secondary vertices inside jets is described. Kinematic properties of the reconstructed vertices are used to construct several b-jet identification algorithms. The features and performance of the secondary vertex finding algorithm in a jet, as well as the performance of the jet tagging algorithms, are studied using simulated $pp$ -> $t\\bar{t}$ events at a centre-of-mass energy of 13 TeV.

  16. Six-vertex model and Schramm-Loewner evolution

    Science.gov (United States)

    Kenyon, Richard; Miller, Jason; Sheffield, Scott; Wilson, David B.

    2017-05-01

    Square ice is a statistical mechanics model for two-dimensional ice, widely believed to have a conformally invariant scaling limit. We associate a Peano (space-filling) curve to a square ice configuration, and more generally to a so-called six-vertex model configuration, and argue that its scaling limit is a space-filling version of the random fractal curve SL E κ, Schramm-Loewner evolution with parameter κ , where 4 <κ ≤12 +8 √{2 } . For square ice, κ =12 . At the "free-fermion point" of the six-vertex model, κ =8 +4 √{3 } . These unusual values lie outside the classical interval 2 ≤κ ≤8 .

  17. Vertex detectors: The state of the art and future prospects

    International Nuclear Information System (INIS)

    Damerell, C.J.S.

    1997-01-01

    We review the current status of vertex detectors (tracking microscopes for the recognition of charm and bottom particle decays). The reasons why silicon has become the dominant detector medium are explained. Energy loss mechanisms are reviewed, as well as the physics and technology of semiconductor devices, emphasizing the areas of most relevance for detectors. The main design options (microstrips and pixel devices, both CCD's and APS's) are discussed, as well as the issue of radiation damage, which probably implies the need to change to detector media beyond silicon for some vertexing applications. Finally, the evolution of key performance parameters over the past 15 years is reviewed, and an attempt is made to extrapolate to the likely performance of detectors working at the energy frontier ten years from now

  18. Development of pixel detectors for SSC vertex tracking

    International Nuclear Information System (INIS)

    Kramer, G.; Shapiro, S.L.; Arens, J.F.; Jernigan, J.G.; Skubic, P.

    1991-04-01

    A description of hybrid PIN diode arrays and a readout architecture for their use as a vertex detector in the SSC environment is presented. Test results obtained with arrays having 256 x 256 pixels, each 30 μm square, are also presented. The development of a custom readout for the SSC will be discussed, which supports a mechanism for time stamping hit pixels, storing their xy coordinates, and storing the analog information within the pixel. The peripheral logic located on the array, permits the selection of those pixels containing interesting data and their coordinates to be selectively read out. This same logic also resolves ambiguous pixel ghost locations and controls the pixel neighbor read out necessary to achieve high spatial resolution. The thermal design of the vertex tracker and the proposed signal processing architecture will also be discussed. 5 refs., 13 figs., 3 tabs

  19. On the zero crossing of the three-gluon vertex

    Energy Technology Data Exchange (ETDEWEB)

    Athenodorou, A. [Department of Physics, University of Cyprus, POB 20537, 1678 Nicosia (Cyprus); Binosi, D., E-mail: binosi@ectstar.eu [European Centre for Theoretical Studies in Nuclear Physics and Related Areas - ECT* and Fondazione Bruno Kessler, Villa Tambosi, Strada delle Tabarelle 286, I-38050 Villazzano (Italy); Boucaud, Ph. [Laboratoire de Physique Théorique (UMR8627), CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay (France); De Soto, F. [Dpto. Sistemas Físicos, Químicos y Naturales, Univ. Pablo de Olavide, 41013 Sevilla (Spain); Papavassiliou, J. [Department of Theoretical Physics and IFIC, University of Valencia-CSIC, E-46100, Valencia (Spain); Rodríguez-Quintero, J. [Department of Integrated Sciences, University of Huelva, E-21071 Huelva (Spain); Zafeiropoulos, S. [Institut für Theoretische Physik, Goethe-Universität Frankfurt, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany)

    2016-10-10

    We report on new results on the infrared behavior of the three-gluon vertex in quenched Quantum Chromodynamics, obtained from large-volume lattice simulations. The main focus of our study is the appearance of the characteristic infrared feature known as ‘zero crossing’, the origin of which is intimately connected with the nonperturbative masslessness of the Faddeev–Popov ghost. The appearance of this effect is clearly visible in one of the two kinematic configurations analyzed, and its theoretical origin is discussed in the framework of Schwinger–Dyson equations. The effective coupling in the momentum subtraction scheme that corresponds to the three-gluon vertex is constructed, revealing the vanishing of the effective interaction at the exact location of the zero crossing.

  20. Analysis of bilinear relation of a six-vertex model

    International Nuclear Information System (INIS)

    Korepin, V.E.

    1982-01-01

    A problem of calculating all matrices of T(μ) monodromy satisfying certain commutation relations for the six-vertex model matrix is considered. The paper presents full description of all accurate L-operators (all monodromy-matrices per one lattice step). It is noted that the a/d function has the simpliest form for L operators, and the corresponding A, B, C, D operators act transitively in rather narrow subspace of the constructed space

  1. The CDF silicon vertex detector SVX and its upgrades

    International Nuclear Information System (INIS)

    Seidel, S.; Univ. of New Mexico, Albuquerque, NM

    1994-11-01

    The three generations of CDF silicon vertex detectors, SVX, SVX', and SVX II, are described. SVX, which operated during Tevatron run Ia, achieved 10.6 μm resolution in r - φ. SVX' is a radiation-hard device for run Ib with a similar but improved mechanical design and improved signal/noise. SVX II, which will be installed for run II, will track in three dimensions with radiation tolerance and electronics appropriate to a Main Injector environment

  2. Silicon vertex detector upgrade in the ALPHA experiment

    CERN Document Server

    Amole, C; Ashkezari, M.D; Baquero-Ruiz, M; Bertsche, W; Burrows, C; Butler, E; Capra, A; Cesar, C.L; Chapman, S; Charlton, M; Deller, A; Eriksson, S; Fajans, J; Friesen, T; Fujiwara, M.C; Gill, D.R; Gutierrez, A; Hangst, J.S; Hardy, W.N; Hayden, M.E; Humphries, A.J; Isaac, C.A; Jonsell, S; Kurchaninov, L; Little, A; Madsen, N; McKenna, J.T.K; Menary, S; Napoli, S.C; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Rasmussen, C.Ø; Robicheaux, F; Sacramento, R.L; Sampson, J.A; Sarid, E; Seddon, D; Silveira, D.M; So, C; Stracka, S; Tharp, T; Thompson, R.I; Thornhill, J; Tooley, M.P; Van Der Werf, D.P; Wells, D

    2013-01-01

    The Silicon Vertex Detector (SVD) is the main diagnostic tool in the ALPHA-experiment. It provides precise spatial and timing information of antiproton (antihydrogen) annihilation events (vertices), and most importantly, the SVD is capable of directly identifying and analysing single annihilation events, thereby forming the basis of ALPHA ' s analysis. This paper describes the ALPHA SVD and its upgrade, installed in the ALPHA ' s new neutral atom trap.

  3. Edge union of networks on the same vertex set

    International Nuclear Information System (INIS)

    Loe, Chuan Wen; Jensen, Henrik Jeldtoft

    2013-01-01

    Random network generators such as Erdős–Rényi, Watts–Strogatz and Barabási–Albert models are used as models to study real-world networks. Let G 1 (V, E 1 ) and G 2 (V, E 2 ) be two such networks on the same vertex set V. This paper studies the degree distribution and clustering coefficient of the resultant networks, G(V, E 1 ∪E 2 ). (paper)

  4. Edge union of networks on the same vertex set

    Science.gov (United States)

    Loe, Chuan Wen; Jeldtoft Jensen, Henrik

    2013-06-01

    Random network generators such as Erdős-Rényi, Watts-Strogatz and Barabási-Albert models are used as models to study real-world networks. Let G1(V, E1) and G2(V, E2) be two such networks on the same vertex set V. This paper studies the degree distribution and clustering coefficient of the resultant networks, G(V, E1∪E2).

  5. Track fitting in the opal vertex detector with stereo wires

    Energy Technology Data Exchange (ETDEWEB)

    Shally, R; Hemingway, R J; McPherson, A C

    1987-10-01

    The geometry of the vertex chamber for the OPAL detector at LEP is reviewed and expressions for the coordinates of the hits are given in terms of the measured drift distance and z-coordinate. The tracks are fitted by a procedure based on the Lagrange multipliers method. The increase in the accuracy of the fit due to the use of the stereo wires is discussed.

  6. General Vertex-Distinguishing Total Coloring of Graphs

    Directory of Open Access Journals (Sweden)

    Chanjuan Liu

    2014-01-01

    Full Text Available The general vertex-distinguishing total chromatic number of a graph G is the minimum integer k, for which the vertices and edges of G are colored using k colors such that any two vertices have distinct sets of colors of them and their incident edges. In this paper, we figure out the exact value of this chromatic number of some special graphs and propose a conjecture on the upper bound of this chromatic number.

  7. Silicon vertex detector upgrade in the ALPHA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Amole, C. [Department of Physics and Astronomy, York University, Toronto, ON, M3J 1P3 (Canada); Andresen, G.B. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Ashkezari, M.D. [Department of Physics, Simon Fraser University, Burnaby, BC, V5A 1S6 (Canada); Baquero-Ruiz, M. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Bertsche, W. [School of Physics and Astronomy, University of Manchester, M13 9PL Manchester (United Kingdom); The Cockcroft Institute, Daresbury Laboratory, WA4 4AD Warrington (United Kingdom); Burrows, C. [Department of Physics, College of Science, Swansea University, Swansea SA2 8PP (United Kingdom); Butler, E. [Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Capra, A. [Department of Physics and Astronomy, York University, Toronto, ON, M3J 1P3 (Canada); Cesar, C.L. [Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972 (Brazil); Chapman, S. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Charlton, M.; Deller, A.; Eriksson, S. [Department of Physics, College of Science, Swansea University, Swansea SA2 8PP (United Kingdom); Fajans, J. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Friesen, T. [Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); Fujiwara, M.C. [Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Gill, D.R. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Gutierrez, A. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z4 (Canada); and others

    2013-12-21

    The Silicon Vertex Detector (SVD) is the main diagnostic tool in the ALPHA-experiment. It provides precise spatial and timing information of antiproton (antihydrogen) annihilation events (vertices), and most importantly, the SVD is capable of directly identifying and analysing single annihilation events, thereby forming the basis of ALPHA's analysis. This paper describes the ALPHA SVD and its upgrade, installed in the ALPHA's new neutral atom trap.

  8. Edge-injective and edge-surjective vertex labellings

    DEFF Research Database (Denmark)

    Brandt, Stephan; Rautenbach, D.; Regen, F.

    2010-01-01

    For a graph G = (V, E) we consider vertex-k-labellings f : V → {1,2, ,k} for which the induced edge weighting w : E → {2, 3,., 2k} with w(uv) = f(u) + f(v) is injective or surjective or both. We study the relation between these labellings and the number theoretic notions of an additive basis and ...

  9. Fatigue crack shape prediction based on vertex singularity

    Czech Academy of Sciences Publication Activity Database

    Hutař, Pavel; Náhlík, Luboš

    2008-01-01

    Roč. 2, č. 1 (2008), s. 45-52 ISSN 1802-680X R&D Projects: GA ČR GA101/08/1623; GA ČR GP106/06/P239 Institutional research plan: CEZ:AV0Z20410507 Keywords : 3D vertex singularity * crack shape * fatigue crack propagation Subject RIV: JL - Materials Fatigue, Friction Mechanics

  10. Vertex maps on graphs -- Perron-Frobenius Theory

    OpenAIRE

    Bernhardt, Chris

    2015-01-01

    The goal of this paper is to describe the connections between Perron-Frobenius theory and vertex maps on graphs. In particular, it is shown how Perron-Frobenius theory gives results about the sets of integers that can arise as periods of periodic orbits, about the concepts of transitivity and topological mixing, and about horseshoes and topological entropy. This is a preprint. The final version will appear in the Journal of Difference Equations and Applications.

  11. Readout ASIC for ILC-FPCCD vertex detector

    International Nuclear Information System (INIS)

    Takubo, Yosuke; Miyamoto, Akiya; Ikeda, Hirokazu; Yamamoto, Hitoshi; Itagaki, Kennosuke; Nagamine, Tadashi; Sugimoto, Yasuhiro

    2010-01-01

    The concept of FPCCD (Fine Pixel CCD) whose pixel size is 5x5μm 2 has been proposed as vertex detector at ILC. Since FPCCD has 128 x20,000 pixels in one readout channel, its readout poses a considerable challenge. We have developed a prototype of readout ASIC to readout the large number of pixels during the inter-train gap of the ILC beam. In this paper, we report the design and performance of the readout ASIC.

  12. Track fitting in the opal vertex detector with stereo wires

    International Nuclear Information System (INIS)

    Shally, R.; Hemingway, R.J.; McPherson, A.C.

    1987-01-01

    The geometry of the vertex chamber for the OPAL detector at LEP is reviewed and expressions for the coordinates of the hits are given in terms of the measured drift distance and z-coordinate. The tracks are fitted by a procedure based on the Lagrange multipliers method. The increase in the accuracy of the fit due to the use of the stereo wires is discussed. (orig.)

  13. The Mark III vertex chamber: Studies using DME

    International Nuclear Information System (INIS)

    Pitman, D.

    1987-04-01

    Studies have been performed using a prototype of a pressurized wire vertex chamber with 8 mm diameter straw geometry. A 35 μm spatial resolution using dimethyl ether (DME) at 1 bar and 30 μm using argon ethane (50/50 mixture) at 4 bar was obtained. Preliminary studies show the DME to adversely affect such materials as aluminized Mylar and Delrin

  14. Development of a silicon tracking and vertex detection system for the CBM experiment at FAIR

    International Nuclear Information System (INIS)

    Heuser, Johann M.

    2007-01-01

    The compressed baryonic matter (CBM) experiment is a fixed-target heavy-ion spectrometer planned at the future international Facility for Antiproton and Ion Research (FAIR) at GSI. The CBM research program will explore the phase diagram of Quantum Chromo Dynamics (QCD) in the region of high baryon chemical potentials, in other words nuclear matter at extreme densities. Matter of such forms is believed to exist in the interior of neutron stars and in the cores of certain types of supernovae. In the laboratory, the dense nuclear medium is created in collisions of heavy-ion beams with nuclear targets. With beam intensities of up to 10 12 ions per pulse, beam energies up to 45 GeV/nucleon, and high availability the SIS-300 synchrotron of FAIR will offer unique opportunities for this research. The CBM detector will identify hadrons and leptons in nuclear collisions with up to 1000 charged particles at event rates up to 10 MHz. The experiment will be optimized in particular for the detection of rare probes, like hadronic decays of D mesons and leptonic decays of light vector mesons, that can yield information on the initial dense phase of the collisions. The challenge is to accomplish in this environment high-resolution charged particle tracking, momentum measurement and secondary vertex selection with a silicon tracking and vertex detection system, the central component of the CBM detector. The system requirements include a very low material budget, radiation tolerant sensors with high spatial resolution, and a fast readout compatible with high-level-only triggers. The paper discusses the concept of the silicon detection system, the optimization of its layout, and the R and D on micro-strip and pixel sensors as well as front-end electronics for the building blocks of the detector stations

  15. Measurement of neutral current deep inelastic e+p scattering cross sections with longitudinally polarized positrons with ZEUS at HERA

    International Nuclear Information System (INIS)

    Wlasenko, Michal

    2009-05-01

    Measurements of neutral current deep inelastic scattering of protons colliding with longitudinally polarized positrons, performed with data recorded in years 2006 and 2007 with the ZEUS detector, corresponding to an integrated luminosity of L=113.3 pb -1 , are presented. The single-differential cross sections dσ/dQ 2 , dσ/dx, dσ/dy and the double-differential reduced cross section σ were measured in the kinematic region of 185 2 2 and y + and the generalized structure function x F 3 were extracted. All measurements agree well with the predictions of the Standard Model. (orig.)

  16. Colour-independent partition functions in coloured vertex models

    Energy Technology Data Exchange (ETDEWEB)

    Foda, O., E-mail: omar.foda@unimelb.edu.au [Dept. of Mathematics and Statistics, University of Melbourne, Parkville, VIC 3010 (Australia); Wheeler, M., E-mail: mwheeler@lpthe.jussieu.fr [Laboratoire de Physique Théorique et Hautes Energies, CNRS UMR 7589 (France); Université Pierre et Marie Curie – Paris 6, 4 place Jussieu, 75252 Paris cedex 05 (France)

    2013-06-11

    We study lattice configurations related to S{sub n}, the scalar product of an off-shell state and an on-shell state in rational A{sub n} integrable vertex models, n∈{1,2}. The lattice lines are colourless and oriented. The state variables are n conserved colours that flow along the line orientations, but do not necessarily cover every bond in the lattice. Choosing boundary conditions such that the positions where the colours flow into the lattice are fixed, and where they flow out are summed over, we show that the partition functions of these configurations, with these boundary conditions, are n-independent. Our results extend to trigonometric A{sub n} models, and to all n. This n-independence explains, in vertex-model terms, results from recent studies of S{sub 2} (Caetano and Vieira, 2012, [1], Wheeler, (arXiv:1204.2089), [2]). Namely, 1.S{sub 2}, which depends on two sets of Bethe roots, {b_1} and {b_2}, and cannot (as far as we know) be expressed in single determinant form, degenerates in the limit {b_1}→∞, and/or {b_2}→∞, into a product of determinants, 2. Each of the latter determinants is an A{sub 1} vertex-model partition function.

  17. Colour-independent partition functions in coloured vertex models

    International Nuclear Information System (INIS)

    Foda, O.; Wheeler, M.

    2013-01-01

    We study lattice configurations related to S n , the scalar product of an off-shell state and an on-shell state in rational A n integrable vertex models, n∈{1,2}. The lattice lines are colourless and oriented. The state variables are n conserved colours that flow along the line orientations, but do not necessarily cover every bond in the lattice. Choosing boundary conditions such that the positions where the colours flow into the lattice are fixed, and where they flow out are summed over, we show that the partition functions of these configurations, with these boundary conditions, are n-independent. Our results extend to trigonometric A n models, and to all n. This n-independence explains, in vertex-model terms, results from recent studies of S 2 (Caetano and Vieira, 2012, [1], Wheeler, (arXiv:1204.2089), [2]). Namely, 1.S 2 , which depends on two sets of Bethe roots, {b 1 } and {b 2 }, and cannot (as far as we know) be expressed in single determinant form, degenerates in the limit {b 1 }→∞, and/or {b 2 }→∞, into a product of determinants, 2. Each of the latter determinants is an A 1 vertex-model partition function

  18. Vertex and Tracker Research and Development for CLIC

    CERN Document Server

    Munker, M

    2017-01-01

    Challenging detector requirements are imposed by the physics goals at the future multi-TeV e+e− Compact Linear Collider (CLIC). A single point resolution of 3 μm for the vertex detector and 7 μm for the tracker is required. Moreover, the CLIC vertex detector and tracker need to be extremely light weighted with a material budget of 0.2%X0 per layer in the vertex detector and 1 - 2%X0 in the tracker. A fast time slicing of 10 ns is further required to suppress background from beam-beam interactions. A wide range of sensor and readout ASIC technologies are investigated within the CLIC silicon pixel R&D; effort. Various hybrid planar sensor assemblies with a pixel size of 25 × 25 μm2 and 55 × 55 μm2 have been produced and characterised by laboratory measurements and during test-beam campaigns. Experimental and simulation results for thin (50 μm- 500 μm) slim edge and active-edge planar, and High-Voltage CMOS sensors hybridised to various readout ASICs (Timepix, Timepix3, CLICpix) are presented.

  19. Technologies for Future Vertex and Tracking Detectors at CLIC

    CERN Document Server

    Spannagel, Simon

    2018-01-01

    CLIC is a proposed linear e$^{+}$e$^{-}$ collider with center-of-mass energies of up to 3 TeV. Its main objectives are precise top quark and Higgs boson measurements, as well as searches for Beyond Standard Model physics. To meet the physics goals, the vertex and tracking detectors require not only a spatial resolution of a few micrometers and a very low material budget, but also timing capabilities with a precision of a few nanoseconds to allow suppression of beam-induced backgrounds. Different technologies using hybrid silicon detectors are explored for the vertex detectors, such as dedicated readout ASICs, small-pitch active edge sensors as well as capacitively coupled High-Voltage CMOS sensors. Monolithic sensors are considered as an option for the tracking detector, and a prototype using a CMOS process with a high-resistivity epitaxial layer is being designed. Different designs using a silicon-on-insulator process are under investigation for both vertex and tracking detector. All prototypes are evaluate...

  20. Charged Particle Tracking and Vertex Detection Group summary report

    International Nuclear Information System (INIS)

    Hanson, G.; Meyer, D.

    1984-09-01

    Charged particle tracking is essential in order to investigate the new physics expected at the SSC. The Tracking Group studied radiation damage and rate limitations to tracking devices, vertex detectors, and central tracking. The Group concluded that silicon strips and large wire tracking chambers with small cells can probably survive at the design luminosity of 10 33 cm -2 sec -1 ; however, the presently designed electronics for silicon strip vertex detectors can withstand a luminosity of only 10 31 cm -2 sec -1 . Wire chambers at a radius of less than about 25 cm can withstand a luminosity of less than or equal to 10 32 cm -2 sec -1 only. Actual tracking and pattern recognition in central tracking chambers at a luminosity of 10 33 cm -2 sec -1 will be very difficult because of multiple interactions within the resolving time of the chambers; detailed simulations are needed in order to decide whether tracking is indeed possible at this luminosity. Scintillating glass fibers are an interesting possibility both for vertex detectors and for central trackers, but much research and development is still needed both on the fibers themselves and on the readout

  1. Data driven processor 'Vertex Trigger' for B experiments

    International Nuclear Information System (INIS)

    Hartouni, E.P.

    1993-01-01

    Data Driven Processors (DDP's) are specialized computation engines configured to solve specific numerical problems, such as vertex reconstruction. The architecture of the DDP which is the subject of this talk was designed and implemented by W. Sippach and B.C. Knapp at Nevis Lab. in the early 1980's. This particular implementation allows multiple parallel streams of data to provide input to a heterogenous collection of simple operators whose interconnection form an algorithm. The local data flow control allows this device to execute algorithms extremely quickly provided that care is taken in the layout of the algorithm. I/O rates of several hundred megabytes/second are routinely achieved thus making DDP's attractive candidates for complex online calculations. The original question was open-quote can a DDP reconstruct tracks in a Silicon Vertex Detector, find events with a separated vertex and do it fast enough to be used as an online trigger?close-quote Restating this inquiry as three questions and describing the answers to the questions will be the subject of this talk. The three specific questions are: (1) Can an algorithm be found which reconstructs tracks in a planar geometry and no magnetic field; (2) Can separated vertices be recognized in some way; (3) Can the algorithm be implemented in the Nevis-UMass and DDP and execute in 10-20 μs?

  2. Track and vertex reconstruction: From classical to adaptive methods

    International Nuclear Information System (INIS)

    Strandlie, Are; Fruehwirth, Rudolf

    2010-01-01

    This paper reviews classical and adaptive methods of track and vertex reconstruction in particle physics experiments. Adaptive methods have been developed to meet the experimental challenges at high-energy colliders, in particular, the CERN Large Hadron Collider. They can be characterized by the obliteration of the traditional boundaries between pattern recognition and statistical estimation, by the competition between different hypotheses about what constitutes a track or a vertex, and by a high level of flexibility and robustness achieved with a minimum of assumptions about the data. The theoretical background of some of the adaptive methods is described, and it is shown that there is a close connection between the two main branches of adaptive methods: neural networks and deformable templates, on the one hand, and robust stochastic filters with annealing, on the other hand. As both classical and adaptive methods of track and vertex reconstruction presuppose precise knowledge of the positions of the sensitive detector elements, the paper includes an overview of detector alignment methods and a survey of the alignment strategies employed by past and current experiments.

  3. Microscopic models for hadronic form factors and vertex functions

    International Nuclear Information System (INIS)

    Santhanam, I.; Bhatnagar, S.; Mitra, A.N.

    1990-01-01

    We review the status of nucleon (N) and few-nucleon form factors (f.f.'s) from the view-point of a gradual unfolding of successively inner degrees of freedom (d.o.f.) with increase in q 2 . To this end we focus attention on the problem of a microscopic formulation of hadronic vertex functions (v.f.) from the point of view of their key role in understanding the physics of a large variety of few-hadron reactions on the one hand, and their practical usefulness in articulating the internal dynamics of hadron and few-hadron systems on the other hand. The criterion of an integrated view from low-energy spectroscopy to high-q 2 amplitudes is employed to emphasize the desirability of formulations in terms of relativistic dynamical equations based on Lorentz and gauge invariance in preference to phenomenological models, which often require additional assumptions beyond their original premises to extend their applicability domains. In this respect, the practical possibilities of the Bethe-Salpeter equation (BSE) in articulating the necessary dynamical ingredients are emphasized on a two-tier basis, the basis constants (3) being pre-determined from the mass spectral data (1 st stage) in preparation for the construction of the hadron-quark vertex functions (2 nd stage). An explicit construction is outlined for meson-quark and baryon-quark vertex functions as well as of meson-nucleon vertex functions in a stepwise fashion. The role of the latter as basic parameter-free ingredients is discussed for possible use in the more serious treatment in the current literature of quark-meson level (α) and meson-isobar (β) d.o.f. in 2-N and 3-N form factor studies. Since most of these studies are characterized by the use of RGM techniques at the six-quark level, a comparative discussion is also given of several contemporary RGM based models. Finally, the concrete prospects for employing such hardon-quark vertex functions for evaluating pp-bar annihilation amplitudes are briefly indicated

  4. Measurement of high-Q2 neutral current cross-sections with longitudinally polarised positrons with the ZEUS detector

    International Nuclear Information System (INIS)

    Stewart, Trevor P.

    2012-07-01

    The cross sections for neutral current (NC) deep inelastic scattering (DIS) in e + p collisions with a longitudinally polarised positron beam are measured at high momentum transfer squared (Q 2 >185 GeV 2 ) at the ZEUS detector at HERA. The HERA accelerator provides e ± p collisions at a centre-of-mass energy of 318 GeV, which allows the weak contribution to the NC process to be studied at high Q 2 . The measurements are based on a data sample with an integrated luminosity of 135.5 pb -1 collected with the ZEUS detector in 2006 and 2007. The single differential NC cross sections dσ/dQ 2 , dσ/dx and dσ/dy and the reduced cross section σ are measured. The structure function xF 3 is determined by combining the e + p NC reduced cross sections with the previously measured e - p measurements. The interference structure function xF 3 γZ is extracted at Q 2 =1500 GeV 2 . The cross-section asymmetry between the positive and negative polarisation of the positron beam is measured and the parity violation effects of the electroweak interaction are observed. The predictions of the Standard Model of particle physics agree well with the measurements. (orig.)

  5. The uranium calorimeter of the ZEUS detector - studies on the uniformity of the energy measurement of electrons

    International Nuclear Information System (INIS)

    Prange, K.

    1991-04-01

    To meet the physics goals at the ep-collider HERA, the compensating uranium scintillator sandwich calorimeter for the ZEUS-Detector has an energy resolution σ/E = 35%/√E + σ cal ; the total calibration error σ cal including overall spatial nonuniformity should be less than 2%. Inhomogeneities occur at the edges of scintillator readout segments. They influence the spatial uniformity of the response of EMC-sections within a calorimeter module as well as between adjacent modules. Both items have been investigated in beam measurements with a spatial granularity of about 1 mm. The nonuniformity for electrons due to the EMC-segmentation within a calolrimeter module is less than 8.3%. That effect is observed in a region of ±4 mm [FWHM] for perpendicular electron incidence. The inhomogeneity at the transition of two modules is compensated by a lead foil of 2.6 mm. Investigations with the prototype calorimeter show the effect on average energy measurement for the ZEUS geometry to be below 2%. (orig.) [de

  6. Measurement of high-Q{sup 2} neutral current cross-sections with longitudinally polarised positrons with the ZEUS detector

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Trevor P.

    2012-07-15

    The cross sections for neutral current (NC) deep inelastic scattering (DIS) in e{sup +}p collisions with a longitudinally polarised positron beam are measured at high momentum transfer squared (Q{sup 2}>185 GeV{sup 2}) at the ZEUS detector at HERA. The HERA accelerator provides e{sup {+-}}p collisions at a centre-of-mass energy of 318 GeV, which allows the weak contribution to the NC process to be studied at high Q{sup 2}. The measurements are based on a data sample with an integrated luminosity of 135.5 pb{sup -1} collected with the ZEUS detector in 2006 and 2007. The single differential NC cross sections d{sigma}/dQ{sup 2}, d{sigma}/dx and d{sigma}/dy and the reduced cross section {sigma} are measured. The structure function xF{sub 3} is determined by combining the e{sup +}p NC reduced cross sections with the previously measured e{sup -}p measurements. The interference structure function xF{sub 3}{sup {gamma}Z} is extracted at Q{sup 2}=1500 GeV{sup 2}. The cross-section asymmetry between the positive and negative polarisation of the positron beam is measured and the parity violation effects of the electroweak interaction are observed. The predictions of the Standard Model of particle physics agree well with the measurements. (orig.)

  7. The MicroBooNE Technical Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, Bonnie [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2012-02-24

    MicroBooNE will build, operate, and extract physics from the first large liquid argon time projection chamber (LArTPC) that will be exposed to a high-intensity neutrino beam. With its unparalleled capabilities in tracking, vertexing, calorimetry, and particle identification, all with full electronic readout, MicroBooNE represents a major advance in detector technology for neutrino physics in the energy regime of most importance for elucidating oscillation phenomena.

  8. Charm photoproduction using electron taggers with the zeus detector at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aghuzumtsyan, G.

    2006-07-15

    Charm production has been studied at a centre-of-mass energy of {radical}(s)=318 GeV in the ZEUS experiment at the electron-proton collider HERA. The data from the years 1998-2000 are used. Photoproduction is identified by reconstructing the D{sup *}(2010) meson via the decay chain D{sup *+}{yields}K{sup -}{pi}{sup +}{pi}{sup +} (+c.c.) and by selecting the scattered electron in one of the dedicated electron taggers located 44m and 35m away from the interaction point. The total visible cross section and differential cross sections as a function of p{sub T}(D{sup *}), {eta}(D{sup *}) and W were measured in the restricted phase space: -1.0<{eta}D({sup *})<1.5, p{sub T}(D{sup *})>1.5 GeV, 80 GeV2.0 GeV, 200 GeV

  9. Peculiar Active-Tectonic Landscape Within the Sanctuary of Zeus at Mt. Lykaion (Peloponnese, Greece)

    Science.gov (United States)

    Davis, G. H.

    2008-12-01

    The Sanctuary of Zeus (Mt. Lykaion) lies in the Peloponnese within the Pindos fold and thrust belt. It is the object of investigation of the Mt. Lykaion Excavation and Survey (http://lykaionexcavation.org/). Mt. Lykaion is a thrust klippe, on the summit of which is an upper sanctuary marked by an ash altar, temenos, and column bases. Earliest objects recovered from the ash altar go back to 3000 BCE, leading Dr. David Romano (University of Pennsylvania), a principal leader of the project, to conclude that worship of divinities on the summit is ancient. Detailed structural geological mapping reveals one dimension of the "power" of the site. Crisscrossing the upper sanctuary are scree bands that mark the traces of active normal faults, which are expressions of tectonic stretching of the Aegean region. The scree bands, composed of cinder-block-sized limestone blocks, range up to 10 m in outcrop breadth, 100 m in length, and 5 m in thickness. Though discontinuous, most of the scree bands lie precisely on the traces of through-going faults, which cut and displace the sedimentary formations of the Pindos group. Some cut the thrust fault, whose elliptical trace defines the Lykaion klippe. What makes the scree bands of this active-tectonic landscape "peculiar" is that there are no cliffs from which the scree descends. Rather, the bands of scree occur along flanks of smooth, rounded hillslopes and ridges. The scree bands coincide with modest steps in the topography, ranging from tens of centimeters to several tens of meters. The specific bedrock formation where the bands are best developed is an Upper Cretaceous limestone whose average platy-bedding thickness (approximately 20 cm) matches closely the average joint spacing. The limestone has little mechanical integrity. It cannot support itself as a scarp footwall and instead collapses into a pile of scree, whose upper-surface inclination conforms to a stable angle of repose. Evidence of the contemporary nature of this

  10. Gauge covariant fermion-photon vertex in quenched, massless three dimensional quantum electrodynamics

    International Nuclear Information System (INIS)

    Tjiang, P.C.; Burden, C.J.

    1998-01-01

    Full text: We consider the problem of designing an Ansatz for the transverse part of the fermion-photon vertex in QED 3 . Our work is based on that of Ball and Chiu, who consider restrictions placed on the vertex by the U(1) Ward identity, and on subsequent modifications which attempt to satisfy the Landau-Khalatnikov transformation rules. A class of vertex Ansaetze including that proposed by Dong et al is tested using the gauge invariance of the vacuum polarisation scalar

  11. Three-coloring graphs with no induced seven-vertex path II : using a triangle

    OpenAIRE

    Chudnovsky, Maria; Maceli, Peter; Zhong, Mingxian

    2015-01-01

    In this paper, we give a polynomial time algorithm which determines if a given graph containing a triangle and no induced seven-vertex path is 3-colorable, and gives an explicit coloring if one exists. In previous work, we gave a polynomial time algorithm for three-coloring triangle-free graphs with no induced seven-vertex path. Combined, our work shows that three-coloring a graph with no induced seven-vertex path can be done in polynomial time.

  12. Intrinsic-normal-ordered vertex operators from the multiloop N-tachyon amplitude

    International Nuclear Information System (INIS)

    Aldazabal, G.; Nunez, C.; Bonini, M.; Iengo, R.

    1987-09-01

    We construct vertex operators for arbitrary mass level states of the closed bosonic string. Starting from a generalization of the Koba-Nielsen amplitude which is suitable for an arbitrary genus Riemann surface, we read the vertex operators from the residues of the poles for the intermediate states. Since the original expression is metric independent and normal ordered without the need of inventing any regularization scheme, our vertex operators also possess these properties. We discuss their general features. (author). 17 refs

  13. cellGPU: Massively parallel simulations of dynamic vertex models

    Science.gov (United States)

    Sussman, Daniel M.

    2017-10-01

    Vertex models represent confluent tissue by polygonal or polyhedral tilings of space, with the individual cells interacting via force laws that depend on both the geometry of the cells and the topology of the tessellation. This dependence on the connectivity of the cellular network introduces several complications to performing molecular-dynamics-like simulations of vertex models, and in particular makes parallelizing the simulations difficult. cellGPU addresses this difficulty and lays the foundation for massively parallelized, GPU-based simulations of these models. This article discusses its implementation for a pair of two-dimensional models, and compares the typical performance that can be expected between running cellGPU entirely on the CPU versus its performance when running on a range of commercial and server-grade graphics cards. By implementing the calculation of topological changes and forces on cells in a highly parallelizable fashion, cellGPU enables researchers to simulate time- and length-scales previously inaccessible via existing single-threaded CPU implementations. Program Files doi:http://dx.doi.org/10.17632/6j2cj29t3r.1 Licensing provisions: MIT Programming language: CUDA/C++ Nature of problem: Simulations of off-lattice "vertex models" of cells, in which the interaction forces depend on both the geometry and the topology of the cellular aggregate. Solution method: Highly parallelized GPU-accelerated dynamical simulations in which the force calculations and the topological features can be handled on either the CPU or GPU. Additional comments: The code is hosted at https://gitlab.com/dmsussman/cellGPU, with documentation additionally maintained at http://dmsussman.gitlab.io/cellGPUdocumentation

  14. Two different cases of calorimetry in high energy physics: the ATLAS liquid argon electromagnetic end cap and the ZEUS forward plug calorimeter

    International Nuclear Information System (INIS)

    Garcia Lopez, G.

    2000-03-01

    The thesis is organised as follows: chapter 1 introduces the basic concepts of calorimetry in high energy physics; chapters 2-5 are devoted to the ATLAS EMEC calorimeter; chapters 6-7 deal with the ZEUS FPC; finally chapter 8 compares the performance of the two calorimeters

  15. Q 2-evolution of parton densities at small x values. Charm contribution in the combined H1 and ZEUS F 2 data

    Science.gov (United States)

    Kotikov, A. V.; Shaikhatdenov, B. G.

    2017-09-01

    The Bessel-inspired behavior of parton densities at small x, obtained in the case of the flat initial conditions for DGLAP evolution equations, is used in the fixed flavor scheme to analyze precise H1 and ZEUS combined data on the structure function F 2.

  16. Effects of Vertex Activity and Self-organized Criticality Behavior on a Weighted Evolving Network

    International Nuclear Information System (INIS)

    Zhang Guiqing; Yang Qiuying; Chen Tianlun

    2008-01-01

    Effects of vertex activity have been analyzed on a weighted evolving network. The network is characterized by the probability distribution of vertex strength, each edge weight and evolution of the strength of vertices with different vertex activities. The model exhibits self-organized criticality behavior. The probability distribution of avalanche size for different network sizes is also shown. In addition, there is a power law relation between the size and the duration of an avalanche and the average of avalanche size has been studied for different vertex activities

  17. Operadic formulation of topological vertex algebras and gerstenhaber or Batalin-Vilkovisky algebras

    International Nuclear Information System (INIS)

    Huang Yizhi

    1994-01-01

    We give the operadic formulation of (weak, strong) topological vertex algebras, which are variants of topological vertex operator algebras studied recently by Lian and Zuckerman. As an application, we obtain a conceptual and geometric construction of the Batalin-Vilkovisky algebraic structure (or the Gerstenhaber algebra structure) on the cohomology of a topological vertex algebra (or of a weak topological vertex algebra) by combining this operadic formulation with a theorem of Getzler (or of Cohen) which formulates Batalin-Vilkovisky algebras (or Gerstenhaber algebras) in terms of the homology of the framed little disk operad (or of the little disk operad). (orig.)

  18. A NEW HYBRID GENETIC ALGORITHM FOR VERTEX COVER PROBLEM

    OpenAIRE

    UĞURLU, Onur

    2015-01-01

    The minimum vertex cover  problem belongs to the  class  of  NP-compl ete  graph  theoretical problems. This paper presents a hybrid genetic algorithm to solve minimum ver tex cover problem. In this paper, it has been shown that when local optimization technique is added t o genetic algorithm to form hybrid genetic algorithm, it gives more quality solution than simple genet ic algorithm. Also, anew mutation operator has been developed especially for minimum verte...

  19. Vertex operator construction of superconformal ghosts and string field theory

    International Nuclear Information System (INIS)

    Ezawa, Z.F.; Nakamura, S.; Tezuka, A.

    1987-01-01

    Superconformal ghosts in string theories are characterized by the SU(1,1) Kac-Moody algebra with central charge -1/2. These ghost fields are constructed as the vertex operators realizing spinor representations of the Kac-Moody algebra. Representations of the canonical commutation relations of the superconformal ghosts are analyzed extensively. All irreducible representations are found to possess only the trivial inner product but for one exceptional case. Consequently, in superstring field theory it is necessary to consider reducible representations in general. Hilbert spaces with a non-trivial inner product are explicitly obtained upon which second quantization of superstring may be carried out. (orig.)

  20. The LHCb vertex locator and level-1 trigger

    CERN Document Server

    Dijkstra, H

    2000-01-01

    LHCb will study CP violation and other rare phenomena in B-decays with a forward detector at the LHC. One of the challenges is to design a fast and efficient trigger. The design of the silicon Vertex Locator (VELO) has been driven by the requirements of one of the most selective triggers of the experiment. The VELO trigger is designed to work at an input rate of 1 MHz. The requirements and implementation of the VELO and the associated trigger are summarised, followed by a description of an upgrade which improves the trigger performance significantly. (3 refs).

  1. A new tool for constrained vertex fitting in ATLAS

    CERN Document Server

    Colijn, Auke Pieter; Limper, Maaike; Prokofiev, Kirill

    2009-01-01

    The precise reconstruction of trajectories of charged and neutral particles and their decay vertices is crucial for many physics analyses. Studying the tracking performance on well known benchmark channels helps to understand the properties of the ATLAS detector during the initial phase of the LHC. In order to exploit the correlations between reconstructed parameters of final state tracks having the same mother particle, a new tool for vertex fitting with possibility of simultaneous application of kinematic constraints has been developed. Using this tool on a benchmark channel such as J/psi to μ+μ− helps to correct shifts in the reconstructed curvature induced by systematic deformations of the detector.

  2. Vertex Normals and Face Curvatures of Triangle Meshes

    KAUST Repository

    Sun, Xiang

    2016-08-12

    This study contributes to the discrete differential geometry of triangle meshes, in combination with discrete line congruences associated with such meshes. In particular we discuss when a congruence defined by linear interpolation of vertex normals deserves to be called a ʼnormal’ congruence. Our main results are a discussion of various definitions of normality, a detailed study of the geometry of such congruences, and a concept of curvatures and shape operators associated with the faces of a triangle mesh. These curvatures are compatible with both normal congruences and the Steiner formula.

  3. W-symmetry, topological vertex and affine Yangian

    Energy Technology Data Exchange (ETDEWEB)

    Procházka, Tomáš [Arnold Sommerfeld Center for Theoretical Physics, Ludwig Maximilian University of Munich,Theresienstr. 37, D-80333 München (Germany); Institute of Physics AS CR,Na Slovance 2, Prague 8 (Czech Republic)

    2016-10-14

    We discuss the representation theory of the non-linear chiral algebra W{sub 1+∞} of Gaberdiel and Gopakumar and its connection to the Yangian of (u(1))-hat whose presentation was given by Tsymbaliuk. The characters of completely degenerate representations of W{sub 1+∞} are given by the topological vertex. The Yangian picture provides an infinite number of commuting charges which can be explicitly diagonalized in W{sub 1+∞} highest weight representations. Many properties that are difficult to study in the W{sub 1+∞} picture turn out to have a simple combinatorial interpretation, once translated to the Yangian picture.

  4. 3D circuit integration for Vertex and other detectors

    Energy Technology Data Exchange (ETDEWEB)

    Yarema, Ray; /Fermilab

    2007-09-01

    High Energy Physics continues to push the technical boundaries for electronics. There is no area where this is truer than for vertex detectors. Lower mass and power along with higher resolution and radiation tolerance are driving forces. New technologies such as SOI CMOS detectors and three dimensional (3D) integrated circuits offer new opportunities to meet these challenges. The fundamentals for SOI CMOS detectors and 3D integrated circuits are discussed. Examples of each approach for physics applications are presented. Cost issues and ways to reduce development costs are discussed.

  5. Performance of the VTL PEPR vertex guidance system

    International Nuclear Information System (INIS)

    Dunn, L.A.; Harris, R.; Kenyon, R.G.; Lubatti, H.J.; Moriyasu, K.

    1975-01-01

    A PEPR vertex guidance system requiring no operator intervention has been operating at the University of Washington's Visual Techniques Laboratory since 1972. The measurement of 140 000 events consisting of 3, 4, 5, and 6-prong interactions of a 15 GeV/c π - beam with deuterium was recently completed. The system employs global transformations that reduce circular tracks to a point in a two-dimensional angle-curvature space. Noise reduction techniques are used to improve position and angle accuracy and thereby the system resolution and efficiency. Monitoring criteria were developed to ensure continuous peak performance over long production periods. (Auth.)

  6. PROPOSAL FOR A SILICON VERTEX TRACKER (VTX) FOR THE PHENIX EXPERIMENT.

    Energy Technology Data Exchange (ETDEWEB)

    AKIBA,Y.

    2004-03-30

    We propose the construction of a Silicon Vertex Tracker (VTX) for the PHENIX experiment at RHIC. The VTX will substantially enhance the physics capabilities of the PHENIX central arm spectrometers. Our prime motivation is to provide precision measurements of heavy-quark production (charm and beauty) in A+A, p(d)+A, and polarized p+p collisions. These are key measurements for the future RHIC program, both for the heavy ion program as it moves from the discovery phase towards detailed investigation of the properties of the dense nuclear medium created in heavy ion collisions, and for the exploration of the nucleon spin-structure functions. In addition, the VTX will also considerably improve other measurements with PHENIX. The main physics topics addressed by the VTX are: (1) Hot and dense strongly interacting matter--Potential enhancement of charm production; Open beauty production; Flavor dependence of jet quenching and QCD energy loss; Accurate charm reference for quarkonium; Thermal dilepton radiation; High p{sub T} phenomena with light flavors above 10-15 GeV/c in p{sub T}; and Upsilon spectroscopy in the e{sup +}e{sup -} decay channel. (2) Gluon spin structure of the nucleon--{Delta}G/G with charm; {Delta}G/G with beauty; and x dependence of {Delta}G/G with {gamma}-jet correlations. (3) Nucleon structure in nuclei--Gluon shadowing over broad x-range. With the present PHENIX detector, heavy-quark production has been measured indirectly through the observation of single electrons. These measurements are inherently limited in accuracy by systematic uncertainties resulting from the large electron background from Dalitz decays and photon conversions. In particular, the statistical nature of the analysis does not allow for a model-independent separation of the charm and beauty contributions. The VTX detector will provide vertex tracking with a resolution of <50 {micro}m over a large coverage both in rapidity (|{eta}| < 1.2) and in azimuthal angle ({Delta}{phi} {approx

  7. Structure of the vertex function in finite quantum electrodynamics

    International Nuclear Information System (INIS)

    Mannheim, P.D.

    1975-01-01

    We study the structure of the renormalized electromagnetic current vertes, GAMMA-tilde/sub μ/(p,p+q,q), in finite quantum electrodynamics. Using conformal invariance we find that GAMMA-tilde/sub μ/(p,p,0) takes the simple form of Z 1 γ/sub μ/ when the external fermions are far off the mass shell. We interpret this result as an old theorem on the structure of the vertex function due to Gell--Mann and Zachariasen. We give the general structure of the vertex for arbitrary momentum transfer parametrically, and discuss how the Bethe--Salpeter equation and the Federbush--Johnson theorem are satisfied. We contrast the meaning of pointlike in a finite field theory with the meaning understood in the parton model. We discuss to what extent the condition Z 1 = 0, which may hold in conformal theories other than finite quantum electrodynamics, may be interpreted as a bootstrap condition. We show that the vanishing of Z 1 prevents their being bound states in the Migdal--Polyakov bootstrap

  8. SPARTex: A Vertex-Centric Framework for RDF Data Analytics

    KAUST Repository

    Abdelaziz, Ibrahim

    2015-08-31

    A growing number of applications require combining SPARQL queries with generic graph search on RDF data. However, the lack of procedural capabilities in SPARQL makes it inappropriate for graph analytics. Moreover, RDF engines focus on SPARQL query evaluation whereas graph management frameworks perform only generic graph computations. In this work, we bridge the gap by introducing SPARTex, an RDF analytics framework based on the vertex-centric computation model. In SPARTex, user-defined vertex centric programs can be invoked from SPARQL as stored procedures. SPARTex allows the execution of a pipeline of graph algorithms without the need for multiple reads/writes of input data and intermediate results. We use a cost-based optimizer for minimizing the communication cost. SPARTex evaluates queries that combine SPARQL and generic graph computations orders of magnitude faster than existing RDF engines. We demonstrate a real system prototype of SPARTex running on a local cluster using real and synthetic datasets. SPARTex has a real-time graphical user interface that allows the participants to write regular SPARQL queries, use our proposed SPARQL extension to declaratively invoke graph algorithms or combine/pipeline both SPARQL querying and generic graph analytics.

  9. The Belle II silicon vertex detector assembly and mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Adamczyk, K. [H. Niewodniczanski Institute of Nuclear Physics, Krakow 31-342 (Poland); Aihara, H. [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan); Angelini, C. [Dipartimento di Fisica, Università di Pisa, I-56127 Pisa (Italy); INFN Sezione di Pisa, I-56127 Pisa (Italy); Aziz, T.; Babu, V. [Tata Institute of Fundamental Research, Mumbai 400005 (India); Bacher, S. [H. Niewodniczanski Institute of Nuclear Physics, Krakow 31-342 (Poland); Bahinipati, S. [Indian Institute of Technology Bhubaneswar, Satya Nagar (India); Barberio, E.; Baroncelli, Ti.; Baroncelli, To. [School of Physics, University of Melbourne, Melbourne, Victoria 3010 (Australia); Basith, A.K. [Indian Institute of Technology Madras, Chennai 600036 (India); Batignani, G. [Dipartimento di Fisica, Università di Pisa, I-56127 Pisa (Italy); INFN Sezione di Pisa, I-56127 Pisa (Italy); Bauer, A. [Institute of High Energy Physics, Austrian Academy of Sciences, 1050 Vienna (Austria); Behera, P.K. [Indian Institute of Technology Madras, Chennai 600036 (India); Bergauer, T. [Institute of High Energy Physics, Austrian Academy of Sciences, 1050 Vienna (Austria); Bettarini, S., E-mail: stefano.bettarini@pi.infn.it [Dipartimento di Fisica, Università di Pisa, I-56127 Pisa (Italy); INFN Sezione di Pisa, I-56127 Pisa (Italy); Bhuyan, B. [Indian Institute of Technology Guwahati, Assam 781039 (India); Bilka, T. [Faculty of Mathematics and Physics, Charles University, 121 16 Prague (Czech Republic); Bosi, F. [INFN Sezione di Pisa, I-56127 Pisa (Italy); Bosisio, L. [Dipartimento di Fisica, Università di Trieste, I-34127 Trieste (Italy); INFN Sezione di Trieste, I-34127 Trieste (Italy); and others

    2017-02-11

    The Belle II experiment at the asymmetric SuperKEKB collider in Japan will operate at an instantaneous luminosity approximately 50 times greater than its predecessor (Belle). The central feature of the experiment is a vertex detector comprising two layers of pixelated silicon detectors (PXD) and four layers of double-sided silicon microstrip detectors (SVD). One of the key measurements for Belle II is CP violation asymmetry in the decays of beauty and charm hadrons, which hinges on a precise charged-track vertex determination and low-momentum track measurement. Towards this goal, a proper assembly of the SVD components with precise alignment ought to be performed and the geometrical tolerances should be checked to fall within the design limits. We present an overview of the assembly procedure that is being followed, which includes the precision gluing of the SVD module components, wire-bonding of the various electrical components, and precision 3D coordinate measurements of the final SVD modules. Finally, some results from the latest test-beam are reported.

  10. Electronics cooling of Phenix multiplicity and vertex detector

    International Nuclear Information System (INIS)

    Chen, Z.; Gregory, W.S.

    1996-08-01

    The Multiplicity and Vertex Detector (MVD) uses silicon strip sensors arranged in two concentric barrels around the beam pipe of the PHENIX detector that will be installed at Brookhaven National Laboratory. Each silicon sensor is connected by a flexible kapton cable to its own front-end electronics printed circuit board that is a multi-chip module or MCM. The MCMs are the main heat source in the system. To maintain the MVD at optimized operational status, the maximum temperature of the multi-chip modules must be below 40 C. Using COSMOS/M HSTAR for the Heat Transfer analysis, a finite element model of a typical MCM plate was created to simulate a 9m/s airflow and 9m/s mixed flow composed of 50% helium and 50% air respectively, with convective heat transfer on both sides of the plate. The results using a mixed flow of helium and air show that the average maximum temperature reached by the MCMs is 37.5 C. The maximum temperature which is represented by the hot spots on the MCM is 39.43 C for the helium and air mixture which meets the design temperature requirement 40 C. To maintain the Multiplicity and Vertex Detector at optimized operational status, the configuration of the plenum chamber, the power dissipated by the silicon chips, the fluid flow velocity and comparison on the MCM design parameters will be discussed

  11. First results with prototype ISIS devices for ILC vertex detector

    International Nuclear Information System (INIS)

    Damerell, C.; Zhang, Z.; Gao, R.; John John, Jaya; Li, Y.; Nomerotski, A.; Holland, A.; Seabroke, G.; Havranek, M.; Stefanov, K.; Kar-Roy, A.; Bell, R.; Burt, D.; Pool, P.

    2010-01-01

    The vertex detectors at the International Linear Collider (ILC) (there will be two of them, one for each of two general purpose detectors) will certainly be built with silicon pixel detectors, either monolithic or perhaps vertically integrated. However, beyond this general statement, there is a wide range of options supported by active R and D programmes all over the world. Pixel-based vertex detectors build on the experience at the SLAC large detector (SLD) operating at the SLAC linear collider (SLC), where a 307 Mpixel detector permitted the highest physics performance at LEP or SLC. For ILC, machine conditions demand much faster readout than at SLC, something like 20 time slices during the 1 ms bunch train. The approach of the image sensor with in-situ storage (ISIS) is unique in offering this capability while avoiding the undesirable requirement of 'pulsed power'. First results from a prototype device that approaches the pixel size of 20 μm square, needed for physics, are reported. The dimensional challenge is met by using a 0.18 μm imaging CMOS process, instead of a conventional CCD process.

  12. First results with prototype ISIS devices for ILC vertex detector

    Energy Technology Data Exchange (ETDEWEB)

    Damerell, C., E-mail: c.damerell@rl.ac.u [RAL, Oxon OX11 0QX (United Kingdom); Zhang, Z. [RAL, Oxon OX11 0QX (United Kingdom); Gao, R.; John John, Jaya; Li, Y.; Nomerotski, A. [Oxford U (United Kingdom); Holland, A.; Seabroke, G. [Centre for Electronic Imaging, Open U (United Kingdom); Havranek, M. [Czech Technical University in Prague (Czech Republic); Stefanov, K. [Sentec Ltd, Cambridge (United Kingdom); Kar-Roy, A. [Jazz Semiconductors, California (United States); Bell, R.; Burt, D.; Pool, P. [e2V Technologies, Chelmsford (United Kingdom)

    2010-12-11

    The vertex detectors at the International Linear Collider (ILC) (there will be two of them, one for each of two general purpose detectors) will certainly be built with silicon pixel detectors, either monolithic or perhaps vertically integrated. However, beyond this general statement, there is a wide range of options supported by active R and D programmes all over the world. Pixel-based vertex detectors build on the experience at the SLAC large detector (SLD) operating at the SLAC linear collider (SLC), where a 307 Mpixel detector permitted the highest physics performance at LEP or SLC. For ILC, machine conditions demand much faster readout than at SLC, something like 20 time slices during the 1 ms bunch train. The approach of the image sensor with in-situ storage (ISIS) is unique in offering this capability while avoiding the undesirable requirement of 'pulsed power'. First results from a prototype device that approaches the pixel size of 20 {mu}m square, needed for physics, are reported. The dimensional challenge is met by using a 0.18 {mu}m imaging CMOS process, instead of a conventional CCD process.

  13. The Mark II vertex detectors: Status and prospects

    International Nuclear Information System (INIS)

    Jaros, J.A.

    1987-03-01

    The art of detecting the decay vertices from heavy quarks and leptons is comparatively new at electron-positron storage rings. So far, drift chambers positioned just outside the vacuum pipes which surround the interfaction region have provided the first accurate determinations of the tau and bottom lifetimes, and confirmed earlier measurements of charmed particle lifetimes. ''Second generation'' vertex detectors have demonstrated the feasibility of tagging heavy flavors by observing decay vertices, and are being used to search for anomalous decay topologies. These chambers have modest resolution on the scale of the effects they seek to measure, but are now well-understood and reliable tools. A generation of vertex detectors, considerably more ambitious, is under construction for experiments at SLC and LEP. They boast impact parameter resolution improved by a factor of four or more over previous detectors, and sub-millimeter track-pair resolution. The Mark II collaboration hopes to reach these goals with a high pressure precision drift chamber, and eventually surpass them with the addition of a silicon microstrip detector

  14. The Mark II vertex detectors: Status and prospects

    Energy Technology Data Exchange (ETDEWEB)

    Jaros, J.A.

    1987-03-01

    The art of detecting the decay vertices from heavy quarks and leptons is comparatively new at electron-positron storage rings. So far, drift chambers positioned just outside the vacuum pipes which surround the interfaction region have provided the first accurate determinations of the tau and bottom lifetimes, and confirmed earlier measurements of charmed particle lifetimes. ''Second generation'' vertex detectors have demonstrated the feasibility of tagging heavy flavors by observing decay vertices, and are being used to search for anomalous decay topologies. These chambers have modest resolution on the scale of the effects they seek to measure, but are now well-understood and reliable tools. A generation of vertex detectors, considerably more ambitious, is under construction for experiments at SLC and LEP. They boast impact parameter resolution improved by a factor of four or more over previous detectors, and sub-millimeter track-pair resolution. The Mark II collaboration hopes to reach these goals with a high pressure precision drift chamber, and eventually surpass them with the addition of a silicon microstrip detector.

  15. Nonperturbative aspects of the quark-photon vertex

    International Nuclear Information System (INIS)

    Frank, M.R.

    1994-01-01

    The electromagnetic interaction with quarks is investigated through a relativistic, electromagnetic gauge-invariant treatment. Gluon dressing of the quark-photon vertex and the quark self-energy functions is described by the inhomogeneous Bethe-Salpeter equation in the ladder approximation and the Schwinger-Dyson equation in the rainbow approximation respectively. Results for the calculation of the quark-photon vertex are presented in both the time-like and space-like regions of photon momentum squared, however emphasis is placed on the space-like region relevant to electron scattering. The treatment presented here simultaneously addresses the role of dynamically generated q bar q vector bound states and the approach to asymptotic behavior. The resulting description is therefore applicable over the entire range of momentum transfers available in electron scattering experiments. Input parameters are limited to the model gluon two-point function which is chosen to reflect confinement and asymptotic freedom and are largely constrained by the obtained bound-state spectrum

  16. The LHCb VELO (VErtex LOcator) and the LHCb VELO upgrade

    International Nuclear Information System (INIS)

    Collins, P.

    2013-01-01

    LHCb is a forward spectrometer experiment dedicated to the study of new physics in the decays of beauty and charm hadrons produced in proton collisions at the Large Hadron Collider (LHC) at CERN. The VErtex LOcator (VELO) is the silicon detector surrounding the LHCb interaction point. The beauty and charm hadrons are identified through their flight distance in the Vertex Locator (VELO), and hence the detector is critical for both the trigger and the offline physics analyses. The sensors, which have an inner radius of ∼7mm from the beam axis at the edge, and the first sensitive strips at a radius of ∼8.2mm are exposed to maximum radiation doses of ∼0.6×10 14 1MeVn eq /cm 2 per integrated luminosity of fb −1 . The performance of the VELO during the first two years of LHC running is described, together with the methods used to monitor radiation damage. The detector so far shows no significant performance degradation, however many interesting effects have been observed in the sensors, including a coupling of charge to the second metal routing line layer after irradiation. In 2018 the VELO will be upgraded together with the rest of the LHCb detector to a 40 MHz readout. The modules together with their front end electronics will be completely replaced with a radiation hard system capable of driving the signals out at the required rates. The current status of the R and D for the LHCb VELO Upgrade is outlined.

  17. Study of the radiation induced effects in the LHCb Vertex Locator

    CERN Document Server

    Szumlak, Tomasz

    2016-01-01

    LHCb is a dedicated heavy-flavour physics experiment at the Large Hadron Collider at CERN. The VErtex LOcator (VELO) is a critical part of a LHCb tracking system, enabling the full topological reconstruction of beauty and charm mesons’ decays and providing essential input for the High Level Trigger (HLT) system used by the experiment to select events. The VELO comprises 42 modules made of two $n^{+}$-on-$n~300~\\mu$m thick half-disc silicon sensors with $R$- and ${\\mit\\Phi}$-measuring micro-strips, arranged in two retractable halves, operating only about 8 mm from the proton beams. In these paper, selected aspects of the VELO performance during the Run 1 data-taking period is shortly summarised along with the radiation damage studies. The track finding efficiency is typically greater than 98\\%. An impact parameter resolution of less than $35~\\mu$m is achieved for particles with transverse momentum greater than 1 GeV/$c$. An overview of all important performance parameters will be given. The VELO sensors have...

  18. Measurement of beauty and charm cross sections in photoproduction using decays into electrons with ZEUS at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Juengst, Markus

    2010-02-15

    Photoproduction of heavy quarks in events with two jets and an electron associated with one of the jets has been studied with the ZEUS detector using the data recorded in the years 1996-2000 and 2006-2007, corresponding to an integrated luminosity of L=120 pb{sup -1} and L=190 pb{sup -1}, respectively. The fractions of events containing b quarks, and also of events containing c quarks, were extracted from a likelihood fit using variables sensitive to electron identification as well as to semileptonic decays. For the second data-set the list of variables sensitive to the flavour could be extended using the additional information from the microvertexdetector. Total and differential cross sections for beauty and charm production were measured for both data-sets and compared with next-to-leading-order QCD calculations and Monte Carlo models. (orig.)

  19. Intersection points for the driving of applier processes of the hardware control of the ZEUS forward detector

    International Nuclear Information System (INIS)

    Siemon, T.

    1992-08-01

    The ZEUS forward detector is built of drift- and transition-radiation chambers which are supported by many peripheral devices. The resulting complex system has to be monitored and controlled continously to preserve safety and to achieve optimal performance. For this task a Hardware-Control-System (HWC) has been developed. Ten VME and OS9-based microprocessors which are connected by Ethernet and VME-bus are provided to run the control- and monitoring tasks. Special attention has been paid to the development of efficient user-interfaces: RDT, an object-oriented database-toolkit, serves as an interface to the data of the HWC. The concept and the usage of this interface are outlined. Finally special features that may be useful for other applications are discussed. (orig.) [de

  20. Measurement of D*± production at low Q2 with the beam-pipe calorimeter of ZEUS at HERA

    International Nuclear Information System (INIS)

    Irrgang, P.

    2004-12-01

    The production of D* mesons in deep-inelastic ep-scattering has been studied using the ZEUS detector at HERA. The total D* production cross-section and the differential cross-sections as functions of Q 2 , y, p t (D*) and η(D*) have been measured at low Q 2 . The data sample used was collected during the period 1998-2000 and amounts to an integrated luminosity of 82.2 pb -1 . The low Q 2 region could be reached using the beam-pipe calorimeter which measures the scattered electron at very small angles. Therefore special emphasis was put on the calibration of the BPC in order to reconstruct events in the kinematic range 0.05 2 2 and 0.02 * +→K - π + π - and the charged conjugated decay in the kinematic region 1.5 t (D*) 2 in agreement with the corresponding perturbative QCD predictions. (orig.)

  1. Development, construction and test of the planar forward drift chambers of the ZEUS inner detector and analyses of chamber properties

    International Nuclear Information System (INIS)

    Kramarczyk, S.

    1993-08-01

    The three planar drift chambers FTD1-3 are part of the inner tracking system of the ZEUS detector at the ep facility HERA, DESY. Together with 2x2 transition radiation modules they form the Forward Detector which covers the range of forward (proton) angles. Development, construction and tests of the drift chambers are described, emphasizing design features and details of the manufacture. Two compensation methods were tested to annihilate the cross talk which emerges from the influence of one signal wire on the others in the same drift cell. A prototyp system of the final digital readout electronics was used together with a test cell. The single wire resolution was studied with optimized drift time algorithms. For the first time it was possible to measure the influence of the track angle on the single wire resolution of the FTDs. (orig.)

  2. Measurement of neutral current cross sections at high Bjorken-x with the ZEUS detector at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)

    2006-07-15

    A new method is employed to measure the neutral current cross section up to Bjorken-x values of one with the ZEUS detector at HERA using an integrated luminosity of 65.1 pb{sup -1} for e{sup +}p collisions and 16.7 pb{sup -1} for e{sup -}p collisions at {radical}(s)=318 GeV and 38.6 pb{sup -1} for e{sup +}p collisions at {radical}(s)=300 GeV. Cross sections have been extracted for Q{sup 2}{>=}648 GeV{sup 2} and are compared to predictions using different parton density functions. For the highest x bins, the data have a tendency to lie above the expectations using recent parton density function parametrizations. (orig.)

  3. Measruement of beauty production in DIS and F{sub 2}{sup b} {sup anti} {sup b} extraction at ZEUS

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Univ. College London (United Kingdom); Max Planck Institute, Munich (Germany); Abt, I. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Cracow (PL). Faculty of Physics and Applied Computer Science] (and others)

    2010-04-15

    Beauty production in deep inelastic scattering with events in which a muon and a jet are observed in the final state has been measured with the ZEUS detector at HERA using an integrated luminosity of 114 pb{sup -1}. The fraction of events with beauty quarks in the data was determined using the distribution of the transverse momentum of the muon relative to the jet. The cross section for beauty production was measured in the kinematic range of photon virtuality, Q{sup 2}>2 GeV{sup 2}, and inelasticity, 0.05

  4. Measurement of neutral current e±p cross sections at high Bjorken x with the ZEUS detector

    International Nuclear Information System (INIS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.

    2013-12-01

    The neutral current e ± p cross section has been measured up to values of Bjorken x≅1 with the ZEUS detector at HERA using an integrated luminosity of 187 pb -1 of e - p and 142 pb -1 of e + p collisions at √(s)=318 GeV. Differential cross sections in x and Q 2 , the exchanged boson virtuality, are presented for Q 2 ≥725 GeV 2 . An improved reconstruction method and greatly increased amount of data allows a finer binning in the high-x region of the neutral current cross section and leads to a measurement with much improved precision compared to a similar earlier analysis. The measurements are compared to Standard Model expectations based on a variety of recent parton distribution functions.

  5. Measurement of neutral current cross sections at high Bjorken-x with the ZEUS detector at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2006-07-01

    A new method is employed to measure the neutral current cross section up to Bjorken-x values of one with the ZEUS detector at HERA using an integrated luminosity of 65.1 pb -1 for e + p collisions and 16.7 pb -1 for e - p collisions at √(s)=318 GeV and 38.6 pb -1 for e + p collisions at √(s)=300 GeV. Cross sections have been extracted for Q 2 ≥648 GeV 2 and are compared to predictions using different parton density functions. For the highest x bins, the data have a tendency to lie above the expectations using recent parton density function parametrizations. (orig.)

  6. Measurement of beauty and charm cross sections in photoproduction using decays into electrons with ZEUS at HERA

    International Nuclear Information System (INIS)

    Juengst, Markus

    2010-02-01

    Photoproduction of heavy quarks in events with two jets and an electron associated with one of the jets has been studied with the ZEUS detector using the data recorded in the years 1996-2000 and 2006-2007, corresponding to an integrated luminosity of L=120 pb -1 and L=190 pb -1 , respectively. The fractions of events containing b quarks, and also of events containing c quarks, were extracted from a likelihood fit using variables sensitive to electron identification as well as to semileptonic decays. For the second data-set the list of variables sensitive to the flavour could be extended using the additional information from the microvertexdetector. Total and differential cross sections for beauty and charm production were measured for both data-sets and compared with next-to-leading-order QCD calculations and Monte Carlo models. (orig.)

  7. Measurement of neutral current e{sup {+-}}p cross sections at high Bjorken x with the ZEUS detector

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max-Planck-Institute for Physics, Munich (Germany); Abt, I. [Max-Planck-Institute for Physics, Munich (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Krakow (Poland). Faculty of Physics and Applied Computer Science; Collaboration: ZEUS Collaboration; and others

    2013-12-15

    The neutral current e{sup {+-}}p cross section has been measured up to values of Bjorken x{approx_equal}1 with the ZEUS detector at HERA using an integrated luminosity of 187 pb{sup -1} of e{sup -}p and 142 pb{sup -1} of e{sup +}p collisions at {radical}(s)=318 GeV. Differential cross sections in x and Q{sup 2}, the exchanged boson virtuality, are presented for Q{sup 2}{>=}725 GeV{sup 2}. An improved reconstruction method and greatly increased amount of data allows a finer binning in the high-x region of the neutral current cross section and leads to a measurement with much improved precision compared to a similar earlier analysis. The measurements are compared to Standard Model expectations based on a variety of recent parton distribution functions.

  8. Effectiveness of Vertex Nomination via Seeded Graph Matching to Find Bijections Between Similar Networks

    Science.gov (United States)

    2018-02-01

    Information Directorate This report is published in the interest of scientific and technical information exchange, and its publication does not...the current prototype. 15. SUBJECT TERMS Vertex Nomination via Seeded Graph Matching (VN via SGM), Seeded Graph Matching (SGM), Vertex of Interest (VOI...Author’s Example ................................................................................................................. 4 4.2.2 Simple

  9. A momentum space analysis of the Triple Pomeron Vertex in pQCD

    International Nuclear Information System (INIS)

    Bartels, J.

    2007-10-01

    We study properties of the momentum space Triple Pomeron Vertex in perturbative QCD. Particular attention is given to the collinear limit where transverse momenta on one side of the vertex are much larger than on the other side. We also comment on the kernels in nonlinear evolution equations. (orig.)

  10. A vertex including emission of spin fields for an arbitrary bc system

    International Nuclear Information System (INIS)

    Di Vecchia, P.; Madsen, R.A.; Roland, K.

    1990-01-01

    We construct the (N+2M) Point Vertex involving the emission of N Neveu-Schwarz and 2M Ramond states for a bosonic and fermionic bc system with a bockground charge Q. From it one can compute correlation functions on the sphere involving any number of spin fields. We show in detail that the vertex satisfies overlap conditions. (orig.)

  11. A momentum space analysis of the Triple Pomeron Vertex in pQCD

    Energy Technology Data Exchange (ETDEWEB)

    Bartels, J. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Kutak, K. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)]|[Instytut Fizyki Jadrowej Polskiej Akademii Nauk, Krakow (Poland)

    2007-10-15

    We study properties of the momentum space Triple Pomeron Vertex in perturbative QCD. Particular attention is given to the collinear limit where transverse momenta on one side of the vertex are much larger than on the other side. We also comment on the kernels in nonlinear evolution equations. (orig.)

  12. A quantum relativistic integrable model as the continuous limit of the six-vertex model

    International Nuclear Information System (INIS)

    Zhou, Y.K.

    1992-01-01

    The six-vertex model in two-dimensional statistical mechanics is used to construct the L-matrix of a one-dimensional quantum relativistic integrable model through a continuous limit. This is the first step to extend the method used earlier by the author to construct quantum completely integrable systems from other well-known two-dimensional vertex models. (orig.)

  13. A quantum hybrid with a thin antenna at the vertex of a wedge

    Energy Technology Data Exchange (ETDEWEB)

    Carlone, Raffaele, E-mail: raffaele.carlone@unina.it [Università “Federico II” di Napoli, Dipartimento di Matematica e Applicazioni “R. Caccioppoli”, MSA, via Cinthia, I-80126, Napoli (Italy); Posilicano, Andrea, E-mail: andrea.posilicano@uninsubria.it [DiSAT, Università dell' Insubria, via Valleggio 11, I-22100, Como (Italy)

    2017-03-26

    We study the spectrum, resonances and scattering matrix of a quantum Hamiltonian on a “hybrid surface” consisting of a half-line attached by its endpoint to the vertex of a concave planar wedge. At the boundary of the wedge, outside the vertex, homogeneous Dirichlet conditions are imposed. The system is tunable by varying the measure of the angle at the vertex. - Highlights: • Spectral characterization of a quantum Hamiltonian on “hybrid surface” consisting of a halfline attached to the vertex of a concave planar wedge. • The system is tunable by varying the measure of the angle at the vertex. • Relation between the conduction properties inside the hybrid and formation of resonances. • Easy generalization of the results to more complicated structures.

  14. The scalar-photon 3-point vertex in massless quenched scalar QED

    International Nuclear Information System (INIS)

    Concha-Sánchez, Y; Gutiérrez-Guerrero, L X; Fernández-Rangel, L A

    2016-01-01

    Non perturbative studies of Schwinger-Dyson equations (SDEs) require their infinite, coupled tower to be truncated in order to reduce them to a practically solvable set. In this connection, a physically acceptable ansatz for the three point vertex is the most favorite choice. Scalar quantum electrodynamics (sQED) provides a simple and neat platform to address this problem. The most general form of the scalar-photon three point vertex can be expressed in terms of only two independent form factors, longitudinal and transverse. Ball and Chiu have demonstrated that the longitudinal vertex is fixed by requiring the Ward-Fradkin-Green- Takahashi identity (WFGTI), while the transverse vertex remains undetermined. In massless quenched sQED, we propose the transverse part of the non perturbative scalar-photon vertex. (paper)

  15. Vertex measurement at a hadron collider. The ATLAS pixel detector

    International Nuclear Information System (INIS)

    Grosse-Knetter, J.

    2008-03-01

    The ATLAS Pixel Detector is the innermost layer of the ATLAS tracking system and will contribute significantly to the ATLAS track and vertex reconstruction. The detector consists of identical sensor-chip-hybrid modules, arranged in three barrels in the centre and three disks on either side for the forward region. The position of the Pixel Detector near the interaction point requires excellent radiation hardness, fast read-out, mechanical and thermal robustness, good long-term stability, all combined with a low material budget. The new design concepts used to meet the challenging requirements are discussed with their realisation in the Pixel Detector, followed by a description of a refined and extensive set of measurements to assess the detector performance during and after its construction. (orig.)

  16. Emergent reduced dimensionality by vertex frustration in artificial spin ice

    Science.gov (United States)

    Gilbert, Ian; Lao, Yuyang; Carrasquillo, Isaac; O'Brien, Liam; Watts, Justin D.; Manno, Michael; Leighton, Chris; Scholl, Andreas; Nisoli, Cristiano; Schiffer, Peter

    2016-02-01

    Reducing the dimensionality of a physical system can have a profound effect on its properties, as in the ordering of low-dimensional magnetic materials, phonon dispersion in mercury chain salts, sliding phases, and the electronic states of graphene. Here we explore the emergence of quasi-one-dimensional behaviour in two-dimensional artificial spin ice, a class of lithographically fabricated nanomagnet arrays used to study geometrical frustration. We extend the implementation of artificial spin ice by fabricating a new array geometry, the so-called tetris lattice. We demonstrate that the ground state of the tetris lattice consists of alternating ordered and disordered bands of nanomagnetic moments. The disordered bands can be mapped onto an emergent thermal one-dimensional Ising model. Furthermore, we show that the level of degeneracy associated with these bands dictates the susceptibility of island moments to thermally induced reversals, thus establishing that vertex frustration can reduce the relevant dimensionality of physical behaviour in a magnetic system.

  17. Displaced vertex searches for sterile neutrinos at future lepton colliders

    Energy Technology Data Exchange (ETDEWEB)

    Antusch, Stefan [Department of Physics, University of Basel, Klingelbergstr. 82, CH-4056 Basel (Switzerland); Max-Planck-Institut für Physik (Werner-Heisenberg-Institut),Föhringer Ring 6, D-80805 München (Germany); Cazzato, Eros; Fischer, Oliver [Department of Physics, University of Basel, Klingelbergstr. 82, CH-4056 Basel (Switzerland)

    2016-12-02

    We investigate the sensitivity of future lepton colliders to displaced vertices from the decays of long-lived heavy (almost sterile) neutrinos with electroweak scale masses and detectable time of flight. As future lepton colliders we consider the FCC-ee, the CEPC, and the ILC, searching at the Z-pole and at the center-of-mass energies of 240, 350 and 500 GeV. For a realistic discussion of the detector response to the displaced vertex signal and the Standard Model background we consider the ILC’s Silicon Detector (SiD) as benchmark for the future lepton collider detectors. We find that displaced vertices constitute a powerful search channel for sterile neutrinos, sensitive to squared active-sterile mixing angles as small as 10{sup −11}.

  18. Greedy Local Search and Vertex Cover in Sparse Random Graphs

    DEFF Research Database (Denmark)

    Witt, Carsten

    2009-01-01

    . This work starts with a rigorous explanation for this claim based on the refined analysis of the Karp-Sipser algorithm by Aronson et al. Subsequently, theoretical supplements are given to experimental studies of search heuristics on random graphs. For c 1, a greedy and randomized local-search heuristic...... finds an optimal cover in polynomial time with a probability arbitrarily close to 1. This behavior relies on the absence of a giant component. As an additional insight into the randomized search, it is shown that the heuristic fails badly also on graphs consisting of a single tree component of maximum......Recently, various randomized search heuristics have been studied for the solution of the minimum vertex cover problem, in particular for sparse random instances according to the G(n, c/n) model, where c > 0 is a constant. Methods from statistical physics suggest that the problem is easy if c

  19. The Small Acceptance Vertex Detector of NA61/SHINE

    Directory of Open Access Journals (Sweden)

    Deveaux M.

    2018-01-01

    Full Text Available Charmonium production in heavy ion collisions is considered as an important diagnostic probe for studying the phase diagram of strongly interacting matter for potential phase transitions. The interpretation of existing data from the CERN SPS is hampered by a lack of knowledge on the properties of open charm particle production in the fireball. Moreover, open charm production in heavy ion collisions by itself is poorly understood. To overcome this obstacle, the NA61/SHINE was equipped with a Small Acceptance Vertex Detector (SAVD, which is predicted to make the experiment sensitive to open charm mesons produced in A-A collisions at the SPS top energy. This paper will introduce the concept and the hardware of the SAVD. Moreover, first running experience as obtained in a commissioning run with a 150 AGeV/c Pb+Pb collision system will be reported.

  20. System software design for the CDF Silicon Vertex Detector

    Energy Technology Data Exchange (ETDEWEB)

    Tkaczyk, S. (Fermi National Accelerator Lab., Batavia, IL (United States)); Bailey, M. (Purdue Univ., Lafayette, IN (United States))

    1991-11-01

    An automated system for testing and performance evaluation of the CDF Silicon Vertex Detector (SVX) data acquisition electronics is described. The SVX data acquisition chain includes the Fastbus Sequencer and the Rabbit Crate Controller and Digitizers. The Sequencer is a programmable device for which we developed a high level assembly language. Diagnostic, calibration and data acquisition programs have been developed. A distributed software package was developed in order to operate the modules. The package includes programs written in assembly and Fortran languages that are executed concurrently on the SVX Sequencer modules and either a microvax or an SSP. Test software was included to assist technical personnel during the production and maintenance of the modules. Details of the design of different components of the package are reported.

  1. Calculation of the Connected Dominating Set Considering Vertex Importance Metrics

    Directory of Open Access Journals (Sweden)

    Francisco Vazquez-Araujo

    2018-01-01

    Full Text Available The computation of a set constituted by few vertices to define a virtual backbone supporting information interchange is a problem that arises in many areas when analysing networks of different natures, like wireless, brain, or social networks. Recent papers propose obtaining such a set of vertices by computing the connected dominating set (CDS of a graph. In recent works, the CDS has been obtained by considering that all vertices exhibit similar characteristics. However, that assumption is not valid for complex networks in which their vertices can play different roles. Therefore, we propose finding the CDS by taking into account several metrics which measure the importance of each network vertex e.g., error probability, entropy, or entropy variation (EV.

  2. Waterbomb base: a symmetric single-vertex bistable origami mechanism

    International Nuclear Information System (INIS)

    Hanna, Brandon H; Lund, Jason M; Magleby, Spencer P; Howell, Larry L; Lang, Robert J

    2014-01-01

    The origami waterbomb base is a single-vertex bistable origami mechanism that has unique properties which may prove useful in a variety of applications. It also shows promise as a test bed for smart materials and actuation because of its straightforward geometry and multiple phases of motion, ranging from simple to more complex. This study develops a quantitative understanding of the symmetric waterbomb base's kinetic behavior. This is done by completing kinematic and potential energy analyses to understand and predict bistable behavior. A physical prototype is constructed and tested to validate the results of the analyses. Finite element and virtual work analyses based on the prototype are used to explore the locations of the stable equilibrium positions and the force–deflection response. The model results are verified through comparisons to measurements on a physical prototype. The resulting models describe waterbomb base behavior and provide an engineering tool for application development. (paper)

  3. System software design for the CDF Silicon Vertex Detector

    International Nuclear Information System (INIS)

    Tkaczyk, S.; Bailey, M.

    1991-11-01

    An automated system for testing and performance evaluation of the CDF Silicon Vertex Detector (SVX) data acquisition electronics is described. The SVX data acquisition chain includes the Fastbus Sequencer and the Rabbit Crate Controller and Digitizers. The Sequencer is a programmable device for which we developed a high level assembly language. Diagnostic, calibration and data acquisition programs have been developed. A distributed software package was developed in order to operate the modules. The package includes programs written in assembly and Fortran languages that are executed concurrently on the SVX Sequencer modules and either a microvax or an SSP. Test software was included to assist technical personnel during the production and maintenance of the modules. Details of the design of different components of the package are reported

  4. Solving Vertex Cover Problem Using DNA Tile Assembly Model

    Directory of Open Access Journals (Sweden)

    Zhihua Chen

    2013-01-01

    Full Text Available DNA tile assembly models are a class of mathematically distributed and parallel biocomputing models in DNA tiles. In previous works, tile assembly models have been proved be Turing-universal; that is, the system can do what Turing machine can do. In this paper, we use tile systems to solve computational hard problem. Mathematically, we construct three tile subsystems, which can be combined together to solve vertex cover problem. As a result, each of the proposed tile subsystems consists of Θ(1 types of tiles, and the assembly process is executed in a parallel way (like DNA’s biological function in cells; thus the systems can generate the solution of the problem in linear time with respect to the size of the graph.

  5. A vertex similarity index for better personalized recommendation

    Science.gov (United States)

    Chen, Ling-Jiao; Zhang, Zi-Ke; Liu, Jin-Hu; Gao, Jian; Zhou, Tao

    2017-01-01

    Recommender systems benefit us in tackling the problem of information overload by predicting our potential choices among diverse niche objects. So far, a variety of personalized recommendation algorithms have been proposed and most of them are based on similarities, such as collaborative filtering and mass diffusion. Here, we propose a novel vertex similarity index named CosRA, which combines advantages of both the cosine index and the resource-allocation (RA) index. By applying the CosRA index to real recommender systems including MovieLens, Netflix and RYM, we show that the CosRA-based method has better performance in accuracy, diversity and novelty than some benchmark methods. Moreover, the CosRA index is free of parameters, which is a significant advantage in real applications. Further experiments show that the introduction of two turnable parameters cannot remarkably improve the overall performance of the CosRA index.

  6. The silicon vertex detector of the Belle II experiment

    Energy Technology Data Exchange (ETDEWEB)

    Adamczyk, K. [H. Niewodniczanski Institute of Nuclear Physics, Krakow 31-342 (Poland); Aihara, H. [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan); Angelini, C. [Dipartimento di Fisica, Universitá di Pisa, I-56127 Pisa (Italy); INFN Sezione di Pisa, I-56127 Pisa (Italy); Aziz, T.; Babu, V. [Tata Institute of Fundamental Research, Mumbai 400005 (India); Bacher, S. [H. Niewodniczanski Institute of Nuclear Physics, Krakow 31-342 (Poland); Bahinipati, S. [Indian Institute of Technology Bhubaneswar, Satya Nagar (India); Barberio, E.; Baroncelli, T. [School of Physics, University of Melbourne, Melbourne, Victoria 3010 (Australia); Basith, A.K. [Indian Institute of Technology Madras, Chennai 600036 (India); Batignani, G. [Dipartimento di Fisica, Universitá di Pisa, I-56127 Pisa (Italy); INFN Sezione di Pisa, I-56127 Pisa (Italy); Bauer, A. [Institute of High Energy Physics, Austrian Academy of Sciences, 1050 Vienna (Austria); Behera, P.K. [Indian Institute of Technology Madras, Chennai 600036 (India); Bergauer, T. [Institute of High Energy Physics, Austrian Academy of Sciences, 1050 Vienna (Austria); Bettarini, S. [Dipartimento di Fisica, Universitá di Pisa, I-56127 Pisa (Italy); INFN Sezione di Pisa, I-56127 Pisa (Italy); Bhuyan, B. [Indian Institute of Technology Guwahati, Assam 781039 (India); Bilka, T. [Faculty of Mathematics and Physics, Charles University, 121 16 Prague (Czech Republic); Bosi, F. [INFN Sezione di Pisa, I-56127 Pisa (Italy); Bosisio, L. [Dipartimento di Fisica, Universitá di Trieste, I-34127 Trieste (Italy); INFN Sezione di Trieste, I-34127 Trieste (Italy); Bozek, A. [H. Niewodniczanski Institute of Nuclear Physics, Krakow 31-342 (Poland); and others

    2016-07-11

    The silicon vertex detector of the Belle II experiment, structured in a lantern shape, consists of four layers of ladders, fabricated from two to five silicon sensors. The APV25 readout ASIC chips are mounted on one side of the ladder to minimize the signal path for reducing the capacitive noise; signals from the sensor backside are transmitted to the chip by bent flexible fan-out circuits. The ladder is assembled using several dedicated jigs. Sensor motion on the jig is minimized by vacuum chucking. The gluing procedure provides such a rigid foundation that later leads to the desired wire bonding performance. The full ladder with electrically functional sensors is consistently completed with a fully developed assembly procedure, and its sensor offsets from the design values are found to be less than 200 μm. The potential functionality of the ladder is also demonstrated by the radioactive source test.

  7. Capacitively coupled hybrid pixel assemblies for the CLIC vertex detector

    CERN Document Server

    AUTHOR|(SzGeCERN)734627; Benoit, Mathieu; Dannheim, Dominik; Dette, Karola; Hynds, Daniel; Kulis, Szymon; Peric, Ivan; Petric, Marko; Redford, Sophie; Sicking, Eva; Valerio, Pierpaolo

    2016-01-01

    The vertex detector at the proposed CLIC multi-TeV linear e+e- collider must have minimal material content and high spatial resolution, combined with accurate time-stamping to cope with the expected high rate of beam-induced backgrounds. One of the options being considered is the use of active sensors implemented in a commercial high-voltage CMOS process, capacitively coupled to hybrid pixel ASICs. A prototype of such an assembly, using two custom designed chips (CCPDv3 as active sensor glued to a CLICpix readout chip), has been characterised both in the lab and in beam tests at the CERN SPS using 120 GeV/c positively charged hadrons. Results of these characterisation studies are presented both for single and dual amplification stages in the active sensor. Pixel cross-coupling results are also presented, showing the sensitivity to placement precision and planarity of the glue layer.

  8. vertex drift chamber construction and test results

    International Nuclear Information System (INIS)

    Clark, A.R.; Goozen, F.; Grudberg, P.; Klopfenstein, C.; Kerth, L.T.; Loken, S.C.; Oltman, E.; Strovink, M.; Trippe, T.G.

    1991-05-01

    A jet-cell based vertex chamber has been built for the D OE experiment at Fermilab and operated in a test beam there. Low drift velocity and diffusion properties were achieved using CO 2 (95%)-ethane(5%) at atmospheric pressure. The drift velocity is found to be consistent with [9.74+8.68(|E|-1.25)] μm/nsec where E is the electric field strength in (kV/cm < |E| z 1.6 kV/cm.) An intrinsic spatial resolution of 60 μm or better for drift distances greater than 2 mm is measured. The track pair efficiency is estimated to be better than 90% for separations greater than 630 μm. 8 refs., 6 figs., 1 tab

  9. Topological vertex, string amplitudes and spectral functions of hyperbolic geometry

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, M.E.X.; Rosa, T.O. [Universidade Federal Fluminense, Instituto de Fisica, Av. Gal. Milton Tavares de Souza, s/n, CEP 24210-346, Niteroi, RJ (Brazil); Luna, R.M. [Universidade Estadual de Londrina, Departamento de Fisica, Caixa Postal 6001, Londrina, Parana (Brazil)

    2014-05-15

    We discuss the homological aspects of the connection between quantum string generating function and the formal power series associated to the dimensions of chains and homologies of suitable Lie algebras. Our analysis can be considered as a new straightforward application of the machinery of modular forms and spectral functions (with values in the congruence subgroup of SL(2,Z)) to the partition functions of Lagrangian branes, refined vertex and open string partition functions, represented by means of formal power series that encode Lie algebra properties. The common feature in our examples lies in the modular properties of the characters of certain representations of the pertinent affine Lie algebras and in the role of Selberg-type spectral functions of a hyperbolic three-geometry associated with q-series in the computation of the string amplitudes. (orig.)

  10. CDF silicon vertex tracker: tevatron run II preliminary results

    International Nuclear Information System (INIS)

    Ashmanskas, W.; Belforte, S.; Budagov, Yu.

    2002-01-01

    The Online Silicon Vertex Tracker (SVT) is the unique new trigger processor dedicated to the 2-D reconstruction of charged particle trajectories at Level 2 of the CDF trigger. The SVT has been successfully built, installed and operated during the 2000 and 20001 CDF data taking runs. The performance of the SVT is already very close to the design. The SVT is able to find tracks and calculate their impact parameter with high precision (σ d = 35 μm). It is possible to correct the beam position offset and give the beam position feedback to accelerator in real time. In fact, the beam position is calculated online every few seconds with an accuracy of 1 to 5 μm. The beam position is continuously sent to the accelerator control. By using trigger tracks, parent particles such as K S 's and D 0 's are reconstructed, proving that the SVT is ready to be used for physics studies

  11. Performance of the ALICE secondary vertex b-tagging algorithm

    CERN Document Server

    INSPIRE-00262232

    2016-11-04

    The identification of jets originating from beauty quarks in heavy-ion collisions is important to study the properties of the hot and dense matter produced in such collisions. A variety of algorithms for b-jet tagging was elaborated at the LHC experiments. They rely on the properties of B hadrons, i.e. their long lifetime, large mass and large multiplicity of decay products. In this work, the b-tagging algorithm based on displaced secondary-vertex topologies is described. We present Monte Carlo based performance studies of the algorithm for charged jets reconstructed with the ALICE tracking system in p-Pb collisions at $\\sqrt{s_\\text{NN}}$ = 5.02 TeV. The tagging efficiency, rejection rate and the correction of the smearing effects of non-ideal detector response are presented.

  12. Quark jets, gluon jets and the three-gluon vertex

    International Nuclear Information System (INIS)

    Fodor, Z.

    1989-11-01

    Using hadronic jets in electron-positron annihilation, we suggest a simple and model-independent method to see the differences between quark and gluon jets. We define and analyse special energy dependent moments of jets and choose those which are the most characteristic to the jet type. The method handles the energy of a jet in an adequate way. We discuss new methods using jet flavor tagging, ordinary flavor tagging of a definite quark jet or discrimination between quark and gluon jets, to test the triple-gluon vertex in electron-positron annihilation. An enriched sample of gluon jets, jets with the smallest energy in four-jet events, as well as a continuous tagging variable are also studied. 21 refs., 6 figs. (Author)

  13. Statistical physics of hard combinatorial optimization: Vertex cover problem

    Science.gov (United States)

    Zhao, Jin-Hua; Zhou, Hai-Jun

    2014-07-01

    Typical-case computation complexity is a research topic at the boundary of computer science, applied mathematics, and statistical physics. In the last twenty years, the replica-symmetry-breaking mean field theory of spin glasses and the associated message-passing algorithms have greatly deepened our understanding of typical-case computation complexity. In this paper, we use the vertex cover problem, a basic nondeterministic-polynomial (NP)-complete combinatorial optimization problem of wide application, as an example to introduce the statistical physical methods and algorithms. We do not go into the technical details but emphasize mainly the intuitive physical meanings of the message-passing equations. A nonfamiliar reader shall be able to understand to a large extent the physics behind the mean field approaches and to adjust the mean field methods in solving other optimization problems.

  14. A new vertex detector made of glass capillaries

    International Nuclear Information System (INIS)

    Annis, P.; Bonekaemper, D.; Buontempo, S.; Ereditato, A.; Fabre, J.D.; Fiorillo, G.; Frekers, D.; Frenkel, A.; Galeazzi, F.; Garufi, F.; Goldberg, J.; Golovkin, S.; Hoepfner, K.; Konijn, J.; Kozarenko, E.; Kreslo, I.; Liberti, B.; Martellotti, G.; Medvedkov, A.; Mommaert, C.; Penso, G.; Petukhov, Y.; Rondeshagen, D.; Tyukov, V.; Vasilchenko, V.; Vilain, P.; Wilquet, G.; Wolff, T.; Wong, H.

    1997-01-01

    We have developed a new detector technique that allows high quality imaging of ionizing particle tracks with very high spatial and time resolution. Central to this technique are liquid-core fibres of about 20 μm diameter read out by an optoelectronic system including a CCD. The fibres act simultaneously as target, detector and light guides. A large-volume prototype, consisting of 5 x 10 5 capillaries of 20 μm diameter and 180 cm length, has been tested in the CERN wide-band neutrino beam. A sample of high-multiplicity neutrino interactions was recorded, demonstrating the imaging quality of this detector. First results from the reconstruction of these events are reported. A track residual of 28 μm and a vertex resolution of 30 μm has been achieved. Future applications of capillary detectors for neutrino and beauty physics are being investigated within the framework of the RD46 collaboration. (orig.)

  15. Micro Engineering

    DEFF Research Database (Denmark)

    Alting, Leo; Kimura, F.; Hansen, Hans Nørgaard

    2003-01-01

    The paper addresses the questions of how micro products are designed and how they are manufactured. Definitions of micro products and micro engineering are discussed and the presentation is aimed at describing typical issues, possibilities and tools regarding design of micro products. The implica......The paper addresses the questions of how micro products are designed and how they are manufactured. Definitions of micro products and micro engineering are discussed and the presentation is aimed at describing typical issues, possibilities and tools regarding design of micro products...

  16. The hadronic final state in the deep inelastic electron-proton scattering. A comparison between the ZEUS data measured 1992 and theoretical models

    International Nuclear Information System (INIS)

    Schneider, J.L.

    1993-12-01

    The hadronic final state in deep inelastic e - P collisions has been studied with the 1992 data from the ZEUS detector at HERA. The hadronic final state is described by event topology variables like thrust and sphericity and also by variables like multiplicity and transverse momentum. These quantities require the reconstruction of the particle four moments which are calculated from calorimeter cell clusters (condensates). A detailed Monte-Carlo comparison between final state particles and condensates is presented. ZEUS data and model predictions are compared in the γ * P system. Good agreement between data and models is found in the x-Feynman and transverse momentum spectra and in the seagull plot. Mean thrust and sphericity are measured as functions of the invariant mass W of the hadronic final state. They significantly deviate from the model predictions, as do the mean multiplicities, which exceed the model predictions by about 1 unit. (orig.)

  17. Measurement of e-p→e-X differential cross sections at high Q2 and of the structure function xF3 with ZEUS at HERA

    International Nuclear Information System (INIS)

    Kappes, A.

    2001-12-01

    The 16 pb -1 of e - p data taken with the ZEUS detector during the 1998/99 running period of HERA have been used to measure neutral current single- and double-differential cross sections in deep inelastic e - p scattering in the range 200 GeV 2 2 2 and 3.7.10 -3 2 is visible. A comparison of the measured e - p cross sections to those from e + p clearly reveals the influence of the Z-boson contribution for Q 2 >or∼ M Z 2 . This dependence is exploited to determine the mass of the Z boson, M Z , and by combining the e - p and e + p cross sections the parity violating structure function xF 3 is extracted for the first time in deep-inelastic ep scattering at ZEUS. (orig.)

  18. Quark-gluon vertex dressing and meson masses beyond ladder-rainbow truncation

    International Nuclear Information System (INIS)

    Matevosyan, Hrayr H.; Thomas, Anthony W.; Tandy, Peter C.

    2007-01-01

    We include a generalized infinite class of quark-gluon vertex dressing diagrams in a study of how dynamics beyond the ladder-rainbow truncation influences the Bethe-Salpeter description of light-quark pseudoscalar and vector mesons. The diagrammatic specification of the vertex is mapped into a corresponding specification of the Bethe-Salpeter kernel, which preserves chiral symmetry. This study adopts the algebraic format afforded by the simple interaction kernel used in previous work on this topic. The new feature of the present work is that in every diagram summed for the vertex and the corresponding Bethe-Salpeter kernel, each quark-gluon vertex is required to be the self-consistent vertex solution. We also adopt from previous work the effective accounting for the role of the explicitly non-Abelian three-gluon coupling in a global manner through one parameter determined from recent lattice-QCD data for the vertex. Within the current model, the more consistent dressed vertex limits the ladder-rainbow truncation error for vector mesons to be never more than 10% as the current quark mass is varied from the u/d region to the b region

  19. The performance of diphoton primary vertex reconstruction methods in H → γγ+Met channel of ATLAS experiment

    Science.gov (United States)

    Tomiwa, K. G.

    2017-09-01

    The search for new physics in the H → γγ+met relies on how well the missing transverse energy is reconstructed. The Met algorithm used by the ATLAS experiment in turns uses input variables like photon and jets which depend on the reconstruction of the primary vertex. This document presents the performance of di-photon vertex reconstruction algorithms (hardest vertex method and Neural Network method). Comparing the performance of these algorithms for the nominal Standard Model sample and the Beyond Standard Model sample, we see the overall performance of the Neural Network method of primary vertex selection performed better than the Hardest vertex method.

  20. Wrong vertex displacements due to Lee-Wick resonances at LHC

    International Nuclear Information System (INIS)

    Alvarez, E.; Schat, C.; Rold, L. da; Szynkman, A.

    2009-01-01

    We show how a resonance from the recently proposed Lee-Wick Standard Model could lead to wrong vertex displacements at LHCb. We study which could be the possible 'longest lived' Lee-Wick particle that could be created at LHC, and we study its possible decays and detections. We conclude that there is a region in the parameter space which would give wrong vertex displacements as a unique signature of the Lee-Wick Standard Model at LHCb. Further numerical simulation shows that LHC era could explore these wrong vertex displacements through Lee-Wick leptons below 500 GeV. (author)

  1. N-point g-loop vertex for free bosonic theory with vacuum charge Q

    International Nuclear Information System (INIS)

    Di Vecchia, P.; Pezzella, F.; Frau, M.; Hornfeck, K.

    1988-12-01

    Starting from the N-Point Vertex on the sphere and using the sewing procedure we construct the N-Point g-Loop Vertex for a free bosonic theory with vacuum charge Q. We then show that, when this vertex is saturated with N highest weight states, it gives their correlation function on an arbitrary Riemann surface of genus g. We also extend our formalism to the case of a free scalar field compactified on a circle, which is related to the Coulomb gas description of minimal models. (orig.)

  2. arXiv Mapping the material in the LHCb vertex locator using secondary hadronic interactions

    CERN Document Server

    INSPIRE-00160626; Barter, W.; Bay, A.; Bel, L.J.; van Beuzekom, M.; Bogdanova, G.; Borghi, S.; Bowcock, T.J.V.; Buchanan, E.; Buytaert, J.; Carvalho Akiba, K.; Chen, S.; Coco, V.; Collins, P.; Crocombe, A.; Da Cunha Marinho, F.; Dall'Occo, E.; De Capua, S.; Dean, C.T.; Dettori, F.; Dossett, D.; Dreimanis, K.; Dujany, G.; Eklund, L.; Evans, T.; Ferro-Luzzi, M.; Gersabeck, M.; Gershon, T.; Hadavizadeh, T.; Harrison, J.; Hennessy, K.; Hulsbergen, W.; Hutchcroft, D.; Ilten, P.; Jans, E.; John, M.; Kopciewicz, P.; Koppenburg, P.; Lafferty, G.; Latham, T.; Leflat, A.; Majewski, M.W.; McNulty, R.; Mylroie-Smith, J.; Oblakowska-Mucha, A.; Parkes, C.; Pearce, A.; Poluektov, A.; Pritchard, A.; Qian, W.; Redford, S.; Richards, S.; Rinnert, K.; Rodrigues, E.; Sarpis, G.; Schiller, M.; Schindler, H.; Smith, M.; Smith, N.A.; Szumlak, T.; Velthuis, J.J.; Volkov, V.; Wallace, C.; Wark, H.M.; Webber, A.; Williams, M.R.J.; Williams, M.

    2018-06-13

    Precise knowledge of the location of the material in the LHCb vertex locator (VELO) is essential to reducing background in searches for long-lived exotic particles, and in identifying jets that originate from beauty and charm quarks. Secondary interactions of hadrons produced in beam-gas collisions are used to map the location of material in the VELO. Using this material map, along with properties of a reconstructed secondary vertex and its constituent tracks, a $p$-value can be assigned to the hypothesis that the secondary vertex originates from a material interaction. A validation of this procedure is presented using photon conversions to dimuons.

  3. On the Relation between Edge and Vertex Modelling in Shape Analysis

    DEFF Research Database (Denmark)

    Hobolth, Asger; Kent, John Thomas; Dryden, Ian L.

    2002-01-01

    Objects in the plane with no obvious landmarks can be described by either vertex transformation vectors or edge transformation vectors. In this paper we provide the relation between the two transformation vectors. Grenander & Miller (1994) use a multivariate normal distribution with a block...... circulant covariance matrix to model the edge transformation vector. This type of model is also feasible for the vertex transformation vector and in certain cases the free parameters of the two models match up in a simple way. A vertex model and an edge model are applied to a data set of sand particles...

  4. The readout of the ZEUS forward detector and studies on the ρ' -resonance in the photoproduction of π+π-- pairs

    International Nuclear Information System (INIS)

    Stamm, J.

    1997-12-01

    Track finding and reconstruction of charged particles close to the beam-line with the ZEUS-detector at HERA uses three planar drift chambers in the forward (FTDs), and one in rear direction (RTD). In addition two pairs of transition radiation detectors (TRD) are located between the FTDs. In 1993-1995 the TRD and FRTD readout systems were included in the global ZEUS data acquisition. A detailed description of the systems is given. In particular the communication between single modules in the components system and the synchronisation with the global ZEUS trigger components are explained. The analysis of photoproduction events of the reaction ep → π + π - p in the region of M ππ > 1.1 GeV with special respect to the track reconstruction with RTD is described in a second part of this report. In this mass region the ρ'-resonance in the decay channel ρ'→ π + π - is studied. The mass peak at 1.6 GeV is best described with a parametrisation including two resonances. Results are also given on the vertical stroke t vertical stroke - and W-dependence of the cross section as well as the polar angular distribution of the decay pions. (orig.)

  5. Archaeological elements of Mt. Lykaion Sanctuary of Zeus (southern Peloponnesus) in relation to tectonics and structural geology

    Energy Technology Data Exchange (ETDEWEB)

    Davis, G H [Regents Professor, University of Arizona, Department of Geosciences, 326 Gould-Simpson Building, Tucson, AZ 85721 (United States)], E-mail: gdavis@u.arizona.edu

    2008-07-01

    The Sanctuary of Zeus is the focus of the Mt. Lykaion Excavation/Survey (University of Pennsylvania, University of Arizona, and 39th Ephorate of Prehistoric and Classical Antiquities). It was described by Pausanias as a sacred place of pan-Hellenic significance, with stadium and hippodrome in which athletic games were held, a sanctuary of Pan, and a formidable temenos and altar of Lykaion Zeus. In picturing human activity on this mountain during ancient times, it is not adequate to treat the mountain as if it were simply a tall, symmetrical, and handy edifice within which rock contents are irrelevant, for the geology within Mt. Lykaion significantly influenced what was built on it, and where{exclamation_point} There are contemporary reminders of the 'power' of the site, including the devastating April, 1965, Megalopolis earthquake, the epicenter of which was merely 4 km away. In fact, there are active normal faults within the sanctuary. However the primary geoarchitecture is that of the Pindos fold and thrust belt, fashioned largely in Cretaceous through Eocene. Mt. Lykaion's dome-like summit is a thrust klippe separated from underlying nappes by a major thrust fault (Lykaion thrust), the subhorizontal trace of which encircles the mountain creating a subtle bench in the landscape coinciding closely with archaeological and natural elements important to the sanctuary (e.g., stoa, seatwall, fountains, trails). Late Jurassic through Eocene 'Pindos Group' formations are stacked and repeated by the thrusting. Inter-relationships between bedrock, structure, and archaeology are revealed in a 'geoarchaeological column,' which displays positioning of elements in relation to the thrust, and orientations of rock formations in relation to flat patches in otherwise steep, rocky country, which became sites suitable for placement of hippodrome, baths, temenos, horse pasturing areas, etc. Worked limestone blocks are locally derived and can be

  6. Archaeological elements of Mt. Lykaion Sanctuary of Zeus (southern Peloponnesus) in relation to tectonics and structural geology

    International Nuclear Information System (INIS)

    Davis, G H

    2008-01-01

    The Sanctuary of Zeus is the focus of the Mt. Lykaion Excavation/Survey (University of Pennsylvania, University of Arizona, and 39th Ephorate of Prehistoric and Classical Antiquities). It was described by Pausanias as a sacred place of pan-Hellenic significance, with stadium and hippodrome in which athletic games were held, a sanctuary of Pan, and a formidable temenos and altar of Lykaion Zeus. In picturing human activity on this mountain during ancient times, it is not adequate to treat the mountain as if it were simply a tall, symmetrical, and handy edifice within which rock contents are irrelevant, for the geology within Mt. Lykaion significantly influenced what was built on it, and where! There are contemporary reminders of the 'power' of the site, including the devastating April, 1965, Megalopolis earthquake, the epicenter of which was merely 4 km away. In fact, there are active normal faults within the sanctuary. However the primary geoarchitecture is that of the Pindos fold and thrust belt, fashioned largely in Cretaceous through Eocene. Mt. Lykaion's dome-like summit is a thrust klippe separated from underlying nappes by a major thrust fault (Lykaion thrust), the subhorizontal trace of which encircles the mountain creating a subtle bench in the landscape coinciding closely with archaeological and natural elements important to the sanctuary (e.g., stoa, seatwall, fountains, trails). Late Jurassic through Eocene 'Pindos Group' formations are stacked and repeated by the thrusting. Inter-relationships between bedrock, structure, and archaeology are revealed in a 'geoarchaeological column,' which displays positioning of elements in relation to the thrust, and orientations of rock formations in relation to flat patches in otherwise steep, rocky country, which became sites suitable for placement of hippodrome, baths, temenos, horse pasturing areas, etc. Worked limestone blocks are locally derived and can be matched with formations. The compelling high elevation of

  7. Pion production and absorption in nuclear reactions. I. The vertex function

    International Nuclear Information System (INIS)

    Nutt, W.T.; Shakin, C.M.

    1977-01-01

    We have performed a model calculation of the pion-nucleon vertex function for the case in which one nucleon is allowed to go far off its mass shell. We discuss the relevance of this vertex function for the calculation of pion production and absorption in nuclear reactions, such as (π + ,p), (p,π + ), and for the pionic disintegration of the deuteron. The model used is based upon an approximation to an exact equation for the vertex function derived from a field-theoretic model with pseudoscalar coupling. Our calculations indicate a strong dependence of the vertex function on the invariant mass of the off-shell nucleon. The results are dominated by the presence of the 1470 MeV, P 11 resonance

  8. Transport coefficients of Dirac ferromagnet: Effects of vertex corrections

    Science.gov (United States)

    Fujimoto, Junji

    2018-03-01

    As a strongly spin-orbit-coupled metallic model with ferromagnetism, we have considered an extended Stoner model to the relativistic regime, named Dirac ferromagnet in three dimensions. In a previous paper [J. Fujimoto and H. Kohno, Phys. Rev. B 90, 214418 (2014), 10.1103/PhysRevB.90.214418], we studied the transport properties giving rise to the anisotropic magnetoresistance (AMR) and the anomalous Hall effect (AHE) with the impurity potential being taken into account only as the self-energy. The effects of the vertex corrections (VCs) to AMR and AHE are reported in this paper. AMR is found not to change quantitatively when the VCs are considered, although the transport lifetime is different from the one-electron lifetime and the charge current includes additional contributions from the correlation with spin currents. The side-jump and the skew-scattering contributions to AHE are also calculated. The skew-scattering contribution is dominant in the clean case as can be seen in the spin Hall effect in the nonmagnetic Dirac electron system.

  9. Error handling for the CDF online silicon vertex tracker

    CERN Document Server

    Bari, M; Cerri, A; Dell'Orso, Mauro; Donati, S; Galeotti, S; Giannetti, P; Morsani, F; Punzi, G; Ristori, L; Spinella, F; Zanetti, A M

    2001-01-01

    The online silicon vertex tracker (SVT) is composed of 104 VME 9U digital boards (of eight different types). Since the data output from the SVT (few MB/s) are a small fraction of the input data (200 MB/s), it is extremely difficult to track possible internal errors by using only the output stream. For this reason, several diagnostic tools have been implemented: local error registers, error bits propagated through the data streams, and the Spy Buffer system. Data flowing through each input and output stream of every board are continuously copied to memory banks named spy buffers, which act as built-in logic state analyzers hooked continuously to internal data streams. The contents of all buffers can be frozen at any time (e.g., on error detection) to take a snapshot of all data flowing through each SVT board. The spy buffers are coordinated at system level by the Spy Control Board. The architecture, design, and implementation of this system are described. (4 refs).

  10. Statistical mechanics of the vertex-cover problem

    Science.gov (United States)

    Hartmann, Alexander K.; Weigt, Martin

    2003-10-01

    We review recent progress in the study of the vertex-cover problem (VC). The VC belongs to the class of NP-complete graph theoretical problems, which plays a central role in theoretical computer science. On ensembles of random graphs, VC exhibits a coverable-uncoverable phase transition. Very close to this transition, depending on the solution algorithm, easy-hard transitions in the typical running time of the algorithms occur. We explain a statistical mechanics approach, which works by mapping the VC to a hard-core lattice gas, and then applying techniques such as the replica trick or the cavity approach. Using these methods, the phase diagram of the VC could be obtained exactly for connectivities c e, the solution of the VC exhibits full replica symmetry breaking. The statistical mechanics approach can also be used to study analytically the typical running time of simple complete and incomplete algorithms for the VC. Finally, we describe recent results for the VC when studied on other ensembles of finite- and infinite-dimensional graphs.

  11. Statistical mechanics of the vertex-cover problem

    International Nuclear Information System (INIS)

    Hartmann, Alexander K; Weigt, Martin

    2003-01-01

    We review recent progress in the study of the vertex-cover problem (VC). The VC belongs to the class of NP-complete graph theoretical problems, which plays a central role in theoretical computer science. On ensembles of random graphs, VC exhibits a coverable-uncoverable phase transition. Very close to this transition, depending on the solution algorithm, easy-hard transitions in the typical running time of the algorithms occur. We explain a statistical mechanics approach, which works by mapping the VC to a hard-core lattice gas, and then applying techniques such as the replica trick or the cavity approach. Using these methods, the phase diagram of the VC could be obtained exactly for connectivities c e, the solution of the VC exhibits full replica symmetry breaking. The statistical mechanics approach can also be used to study analytically the typical running time of simple complete and incomplete algorithms for the VC. Finally, we describe recent results for the VC when studied on other ensembles of finite- and infinite-dimensional graphs

  12. The upgrade of the LHCb Vertex Locator (VELO)

    CERN Document Server

    van Beuzekom, M

    2014-01-01

    The upgrade of the LHCb experiment, planned for 2018, will enable the detector to run at a luminosity of 2 x 10$^{33}$ cm$^{-22}$s$^{-1}$ and explore New Physics effects in the beauty and charm sector with unprecedented precision. To achieve this, the entire readout will be transformed into a triggerless system operating at 40 MHz, where the event selection algorithms will be executed by high-level software in the CPU farm. The upgraded silicon vertex detector (VELO) must be lightweight, radiation hard, vacuum compatible, and has to drive data to the data acquisition system at speeds of up to 3 Tbit/s. This challenge will be met with a new VELO design based on hybrid pixel detectors, positioned to within 5 mm of the LHC colliding beams. The sensors have 55 x 55 $\\mu$m$^2$ square pixels and the VeloPix ASIC, which is being developed for the readout, is based on the Timepix/Medipix family of chips. The hottest ASIC will have to cope with integrated hit rates of up to 900 MHz which translates to a bandwidth of m...

  13. Asymptotic normalization coefficients, nuclear vertex constants and nuclear astrophysics problems

    International Nuclear Information System (INIS)

    Yarmukhamedov, R.; Artemov, S.V.; Igamov, S.B.; Burtebaev, N.; Peterson, R.J.

    2007-01-01

    Full text: We will review the results of a comprehensive analysis of the experimental astrophysical S- factors S(E) for the t(α, γ ) 7 Li, 3 He(α, γ) 7 Be, 7 Be(p, γ) 8 B, 12 C(p , γ) 13 N and 13 C(p,γ) 14 N reactions at extremely low energies, performed within a three-sided collaboration (Uzbekistan-Kazakhstan-USA). In the analysis, the new experimental data for the 12 C(p, γ) 13 N reaction are also included, as measured with the accelerator UKP-2-1 at the Institute of Nuclear Physics in Kazakhstan. The analysis is carried out within the framework of a new two-body potential approach and the R-matrix method, taking into account information about the asymptotic normalization coefficient (ANC) (or the respective nuclear vertex constant for virtual decay of the residual nuclei into two fragments of the initial states of the aforesaid reactions, which belong to the fundamental nuclear constants). Nowadays ANC's are obtained from analysis of peripheral one nucleon transfer reactions by method combining dispersion theory and DWBA (CM). It is shown that ANC can be also reliably obtained from analysis of proton capture reactions at astrophysical energies by new modified two-body potential method where the CM is used. A comparative analysis of the results obtained by different authors in the framework of different methods is also done

  14. The silicon vertex detector of the Belle II experiment

    Energy Technology Data Exchange (ETDEWEB)

    Friedl, Markus, E-mail: friedl@hephy.a [Institute of High Energy Physics, Nikolsdorfergasse 18, A-1050 Vienna (Austria); Bergauer, Thomas; Gfall, Immanuel; Irmler, Christian; Valentan, Manfred [Institute of High Energy Physics, Nikolsdorfergasse 18, A-1050 Vienna (Austria)

    2011-02-01

    After 10 years of successful operation, the Belle experiment at KEK (Tsukuba, Japan) will be completed in 2010. Thereafter, a major upgrade of the KEK-B machine is foreseen until 2014, aiming at a final luminosity of 8x10{sup 35} cm{sup -2} s{sup -1}, which is about 40 times higher than the present peak value. Consequently, also the Belle experiment needs to be changed and the Silicon Vertex Detector (SVD) in particular will be completely replaced as it already operates close to its limits in the present system. The future SVD (a.k.a. SuperSVD) will consist of four layers of double-sided silicon strip detectors like the present one, but at larger radii, because it will be complemented by a two-layer pixel detector as the innermost sensing device. The SuperSVD will be entirely composed of silicon sensors made from 6 in. wafers read out by APV25 front-end chips that were originally developed for the CMS experiment at the LHC. Several years of R and D effort led to innovations such as the Origami chip-on-sensor concept and readout electronics with hit time finding which were successfully demonstrated on prototypes. These features will be included in the final system which is presently being designed. This paper will give an overview of the SuperSVD and present results from prototype tests ranging from detector modules to back-end electronics.

  15. The silicon vertex detector of the Belle II experiment

    International Nuclear Information System (INIS)

    Friedl, Markus; Bergauer, Thomas; Gfall, Immanuel; Irmler, Christian; Valentan, Manfred

    2011-01-01

    After 10 years of successful operation, the Belle experiment at KEK (Tsukuba, Japan) will be completed in 2010. Thereafter, a major upgrade of the KEK-B machine is foreseen until 2014, aiming at a final luminosity of 8x10 35 cm -2 s -1 , which is about 40 times higher than the present peak value. Consequently, also the Belle experiment needs to be changed and the Silicon Vertex Detector (SVD) in particular will be completely replaced as it already operates close to its limits in the present system. The future SVD (a.k.a. SuperSVD) will consist of four layers of double-sided silicon strip detectors like the present one, but at larger radii, because it will be complemented by a two-layer pixel detector as the innermost sensing device. The SuperSVD will be entirely composed of silicon sensors made from 6 in. wafers read out by APV25 front-end chips that were originally developed for the CMS experiment at the LHC. Several years of R and D effort led to innovations such as the Origami chip-on-sensor concept and readout electronics with hit time finding which were successfully demonstrated on prototypes. These features will be included in the final system which is presently being designed. This paper will give an overview of the SuperSVD and present results from prototype tests ranging from detector modules to back-end electronics.

  16. Automatised Data Quality Monitoring of the LHCb Vertex Locator

    CERN Multimedia

    Szumlak, Tomasz

    2016-01-01

    The LHCb Vertex Locator (VELO) is a silicon strip semiconductor detector operating at just 8mm distance to the LHC beams. Its 172,000 strips are read at a frequency of 1 MHz and processed by off-detector FPGAs followed by a PC cluster that reduces the event rate to about 10 kHz. During the second run of the LHC, which lasts from 2015 until 2018, the detector performance will undergo continued change due to radiation damage effects. This necessitates a detailed monitoring of the data quality to avoid adverse effects on the physics analysis performance. The VELO monitoring infrastructure has been re-designed compared to the first run of the LHC when it was based on manual checks. The new system is based around an automatic analysis framework, which monitors the performance of new data as well as long-term trends and flags issues whenever they arise. An unbiased subset of the detector data are processed about once per hour by monitoring algorithms. The new analysis framework then analyses the plots that are prod...

  17. Error handling for the CDF Silicon Vertex Tracker

    CERN Document Server

    Belforte, S; Dell'Orso, Mauro; Donati, S; Galeotti, S; Giannetti, P; Morsani, F; Punzi, G; Ristori, L; Spinella, F; Zanetti, A M

    2000-01-01

    The SVT online tracker for the CDF upgrade reconstructs two- dimensional tracks using information from the Silicon Vertex detector (SVXII) and the Central Outer Tracker (COT). The SVT has an event rate of 100 kHz and a latency time of 10 mu s. The system is composed of 104 VME 9U digital boards (of 8 different types) and it is implemented as a data driven architecture. Each board runs on its own 30 MHz clock. Since the data output from the SVT (few Mbytes/sec) are a small fraction of the input data (200 Mbytes/sec), it is extremely difficult to track possible internal errors by using only the output stream. For this reason several diagnostic tools have been implemented: local error registers, error bits propagated through the data streams and the Spy Buffer system. Data flowing through each input and output stream of every board are continuously copied to memory banks named Spy Buffers which act as built in logic state analyzers hooked continuously to internal data streams. The contents of all buffers can be ...

  18. Jet Vertex Charge Reconstruction Poster for LHCP 2015

    CERN Document Server

    Nektarijevic, Snezana; The ATLAS collaboration

    2015-01-01

    B-jet reconstruction algorithms used so far in ATLAS data analyses do not provide the b-jet charge information, which could potentially play a major role in reducing the combinatorial backgrounds in final states with multiple b-jets. This missing point is addressed by the newly developed JetVertexCharge (JVC) algorithm presented in this poster. Inspired by the decay chain of B-hadrons, the JVC algorithm provides a multi-variate b-jet charge estimate relying on tracks, displaced vertices and muons contained in the jet. In this algorithm, the established concept of estimating jet charge as a transverse momentum weighted sum of track charges is used to reconstruct the charge of the jet as whole, as well as the charges of up to two displaced vertices in the jet, using the corresponding sets of associated tracks. The charge of the associated muon is interpreted as the same-sign or opposite-sign relative to the b-jet charge, according to its transverse momentum and geometrical match to vertices. Jets are divided in...

  19. A dynamic cellular vertex model of growing epithelial tissues

    Science.gov (United States)

    Lin, Shao-Zhen; Li, Bo; Feng, Xi-Qiao

    2017-04-01

    Intercellular interactions play a significant role in a wide range of biological functions and processes at both the cellular and tissue scales, for example, embryogenesis, organogenesis, and cancer invasion. In this paper, a dynamic cellular vertex model is presented to study the morphomechanics of a growing epithelial monolayer. The regulating role of stresses in soft tissue growth is revealed. It is found that the cells originating from the same parent cell in the monolayer can orchestrate into clustering patterns as the tissue grows. Collective cell migration exhibits a feature of spatial correlation across multiple cells. Dynamic intercellular interactions can engender a variety of distinct tissue behaviors in a social context. Uniform cell proliferation may render high and heterogeneous residual compressive stresses, while stress-regulated proliferation can effectively release the stresses, reducing the stress heterogeneity in the tissue. The results highlight the critical role of mechanical factors in the growth and morphogenesis of epithelial tissues and help understand the development and invasion of epithelial tumors.

  20. On the complexity of the balanced vertex ordering problem

    Directory of Open Access Journals (Sweden)

    Jan Kara

    2007-01-01

    Full Text Available We consider the problem of finding a balanced ordering of the vertices of a graph. More precisely, we want to minimise the sum, taken over all vertices v, of the difference between the number of neighbours to the left and right of v. This problem, which has applications in graph drawing, was recently introduced by Biedl et al. [Discrete Applied Math. 148:27--48, 2005]. They proved that the problem is solvable in polynomial time for graphs with maximum degree three, but NP-hard for graphs with maximum degree six. One of our main results is to close the gap in these results, by proving NP-hardness for graphs with maximum degree four. Furthermore, we prove that the problem remains NP-hard for planar graphs with maximum degree four and for 5-regular graphs. On the other hand, we introduce a polynomial time algorithm that determines whetherthere is a vertex ordering with total imbalance smaller than a fixed constant, and a polynomial time algorithm that determines whether a given multigraph with even degrees has an `almost balanced' ordering.

  1. Persistent magnetic vortex flow at a supergranular vertex

    Science.gov (United States)

    Requerey, Iker S.; Cobo, Basilio Ruiz; Gošić, Milan; Bellot Rubio, Luis R.

    2018-03-01

    Context. Photospheric vortex flows are thought to play a key role in the evolution of magnetic fields. Recent studies show that these swirling motions are ubiquitous in the solar surface convection and occur in a wide range of temporal and spatial scales. Their interplay with magnetic fields is poorly characterized, however. Aims: We study the relation between a persistent photospheric vortex flow and the evolution of a network magnetic element at a supergranular vertex. Methods: We used long-duration sequences of continuum intensity images acquired with Hinode and the local correlation-tracking method to derive the horizontal photospheric flows. Supergranular cells are detected as large-scale divergence structures in the flow maps. At their vertices, and cospatial with network magnetic elements, the velocity flows converge on a central point. Results: One of these converging flows is observed as a vortex during the whole 24 h time series. It consists of three consecutive vortices that appear nearly at the same location. At their core, a network magnetic element is also detected. Its evolution is strongly correlated to that of the vortices. The magnetic feature is concentrated and evacuated when it is caught by the vortices and is weakened and fragmented after the whirls disappear. Conclusions: This evolutionary behavior supports the picture presented previously, where a small flux tube becomes stable when it is surrounded by a vortex flow. A movie attached to Fig. 2 is available at http://https://www.aanda.org

  2. From vertex detectors to inner trackers with CMOS pixel sensors

    CERN Document Server

    Besson, A.

    2017-01-01

    The use of CMOS Pixel Sensors (CPS) for high resolution and low material vertex detectors has been validated with the 2014 and 2015 physics runs of the STAR-PXL detector at RHIC/BNL. This opens the door to the use of CPS for inner tracking devices, with 10-100 times larger sensitive area, which require therefore a sensor design privileging power saving, response uniformity and robustness. The 350 nm CMOS technology used for the STAR-PXL sensors was considered as too poorly suited to upcoming applications like the upgraded ALICE Inner Tracking System (ITS), which requires sensors with one order of magnitude improvement on readout speed and improved radiation tolerance. This triggered the exploration of a deeper sub-micron CMOS technology, Tower-Jazz 180 nm, for the design of a CPS well adapted for the new ALICE-ITS running conditions. This paper reports the R&D results for the conception of a CPS well adapted for the ALICE-ITS.

  3. Readout and trigger electronics for the TPC vertex chamber

    International Nuclear Information System (INIS)

    Ronan, M.T.; Jared, R.C.; McGathen, T.K.; Eisner, A.M.; Broeder, W.J.; Godfrey, G.L.

    1987-10-01

    The introduction of the vertex chamber required the addition of new front-end electronics and a new 1024-channel, high-accuracy TDC system. The preamplifier/discriminator should be capable of triggering on the first electrons and the time digitzer should preserve the measurement resolution. For the TDC's, in order to maintain compatibility with the existing TPC readout system, an upgrade of a previous inner drift chamber digitizer system has been chosen. Tests of the accuracy and stability of the original design indicated that the new design specifications would be met. The TPC detector requires a fast pretrigger to turn on its gating grid within 500 ns of the e/sup +/e/sup -/ beam crossing time, to minimize the loss of ionization information. A pretrigger based on the Straw Chamber signals, operating at a rate of about 2 K/sec, will be used for charged particle final states. In addition, in order to reject low mass Two-Photon events at the final trigger level, an accurate transverse momentum cutoff will be made by the Straw Chamber trigger logic. In this paper, we describe the readout and trigger electronics systems which have been built to satisfy the above requirements. 5 refs., 8 figs

  4. Characterisation of silicon detectors for the LHCb Vertex Locator Upgrade

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00401830

    The LHCb Vertex Locator must be upgraded in the next long shutdown of the LHC, starting at the end of 2018. This is due to the increased occupancy. The current silicon strip detector is being upgraded to a silicon pixel detector. The prototype sensors for this detector were tested thoroughly before a final design will be chosen. The testing was done with the Timepix3 Telescope, which was commissioned in the summer of 2014. The charge collected by the sensors and efficiency of the sensors were investigated. After maximum irradiation, of 8$\\times$10$^{15}$ 1 MeV n$_{eq}$/cm$^{2}$, the sensors must have a most probable value of collected charge of 6000 electrons before 1000 V or breakdown, whichever comes first. The sensors must also have a high efficiency at maximum irradiation of 8$\\times$10$^{15}$ 1 MeV n$_{eq}$/cm$^{2}$. All tested sensors reach these criteria. All sensors reach 6000 electrons between 600 V and 800 V and have a cluster finding efficiency of over 95\\% at the respective voltages. Overall, a 15...

  5. Development of a signal-analysis algorithm for the ZEUS transition-radiation detector under application of a neural network

    International Nuclear Information System (INIS)

    Wollschlaeger, U.

    1992-07-01

    The aim of this thesis consisted in the development of a procedure for the analysis of the data of the transition-radiation detector at ZEUS. For this a neural network was applied and first studied, which results concerning the separation power between electron an pions can be reached by this procedure. It was shown that neural nets yield within the error limits as well results as standard algorithms (total charge, cluster analysis). At an electron efficiency of 90% pion contaminations in the range 1%-2% were reached. Furthermore it could be confirmed that neural networks can be considered for the here present application field as robust in relatively insensitive against external perturbations. For the application in the experiment beside the separation power also the time-behaviour is of importance. The requirement to keep dead-times small didn't allow the application of standard method. By a simulation the time availabel for the signal analysis was estimated. For the testing of the processing time in a neural network subsequently the corresponding algorithm was implemented into an assembler code for the digital signal processor DSP56001. (orig./HSI) [de

  6. The triad Zeus, Herakles and Dionysos a contribution to the study of ancient cults in upper Moesia

    Directory of Open Access Journals (Sweden)

    Pilipović Sanja

    2008-01-01

    Full Text Available The triad Zeus, Herakles and Dionysos has been attested in Upper Moesia by the relief from the village of Bukovo near Negotin, eastern Serbia. The Roman supreme god was frequently shown in association with other deities but the presence of Bacchus and Hercules in such associations is Greek rather than Roman in origin. The association of Liber and Hercules was promoted by the emperor Septimius Severus, a native of the city of Leptis Magna whose patron gods were concurrently Liber and Hercules. Septimius even granted the dii patrii a sort of official recognition as patrons of the dynasty he founded. The village of Bukovo where the relief was found had not been known as an archaeological site. There is no specific evidence for the worship of Jupiter in that area, while the worship of Herakles is attested on the sites of Rovine and Tamnič near Negotin. The relief is close to north-Macedonian reliefs in style, and reflects Hellenistic and Thracian influence in associating the cults of Dionysos and Herakles. The depicted deities are compatible and close to Septimius Severus’ official religion. The central position of the supreme god indicates his importance as well as the fact that the other two deities are associated to him, as his children patrons of nature and fertility in the underground and aboveground worlds. It is also important to note that the relief confirms Hellenistic religious influences in the area of the Upper Moesian limes.

  7. A measurement of multijet production in low-x{sub Bj} neutral current deep inelastic scattering with ZEUS at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Danielson, T.E.

    2007-12-15

    Inclusive dijet and trijet production in deep inelastic ep scattering has been measured for 10ZEUS detector and correspond to an integrated luminosity of 82 pb{sup -1}. Jets were identified in the hadronic center-of-mass (HCM) frame using the k{sub T} cluster algorithm in the longitudinally invariant inclusive mode. Measurements of dijet and trijet differential cross sections are presented as functions of Q{sup 2}, x{sub Bj}, jet transverse energy, and jet pseudorapidity. As a further examination of low-x{sub Bj} dynamics, multi-differential cross sections as functions of the jet correlations in transverse momenta, azimuthal angles, and pseudorapidity are also presented. Calculations at O({alpha}{sup 3}{sub s}) generally describe the trijet data well and improve the description of the dijet data compared to the calculation at O({alpha}{sup 2}{sub s}). (orig.)

  8. Automated Damage Onset Analysis Techniques Applied to KDP Damage and the Zeus Small Area Damage Test Facility

    International Nuclear Information System (INIS)

    Sharp, R.; Runkel, M.

    1999-01-01

    Automated damage testing of KDP using LLNL's Zeus automated damage test system has allowed the statistics of KDP bulk damage to be investigated. Samples are now characterized by the cumulative damage probability curve, or S-curve, that is generated from hundreds of individual test sites per sample. A HeNe laser/PMT scatter diagnostic is used to determine the onset of damage at each test site. The nature of KDP bulk damage is such that each scatter signal may possess many different indicators of a damage event. Because of this, the determination of the initial onset for each scatter trace is not a straightforward affair and has required considerable manual analysis. The amount of testing required by crystal development for the National Ignition Facility (NIF) has made it impractical to continue analysis by hand. Because of this, we have developed and implemented algorithms for analyzing the scatter traces by computer. We discuss the signal cleaning algorithms and damage determination criteria that have lead to the successful implementation of a LabView based analysis code. For the typical R/1 damage data set, the program can find the correct damage onset in more than 80% of the cases, with the remaining 20% being left to operator determination. The potential time savings for data analysis is on the order of ∼ 100X over manual analysis and is expected to result in the savings of at least 400 man-hours over the next 3 years of NIF quality assurance testing

  9. COMPUTER AIDED RESTORATION TOOLS TO ASSIST THE CONSERVATION OF AN ANCIENT SCULPTURE. THE COLOSSAL STATUE OF ZEUS ENTHRONED

    Directory of Open Access Journals (Sweden)

    F. Di Paola

    2017-08-01

    Full Text Available The research focuses on the contribution of the integrated application of Computer Aided Restoration digital procedures as a means to guide the integration measure of an artifact, innovating and implementing the traditional investigation methods. The aim of the study was to provide effective geometrical-formal investigation tools in the frame of the conservation work of Zeus enthroned from Soluntum, conserved in the Archaeological Museum “A. Salinas” of Palermo. The paper describes the workflow of the 3D acquisition and graphical modeling with non-invasive digitalization and high information density techniques to assist the conservation of the legs of the throne, especially the integration of the missing part. Thanks to the technique of the digital fabrication it has been reconstruct the two missing parts following the theoretical criteria as: recognisability, compatibility and retractability. This innovative application of 3D digital technologies have showed as the integrated use of the new technology can be a useful tools for improving the conservation of a work of art.

  10. Measurement of the diffractive structure function of the proton in deep inelastic ep scattering with the ZEUS detector

    International Nuclear Information System (INIS)

    Doeker, T.

    1995-10-01

    The analysis of deep inelastic scattering events at the ep collider HERA at DESY has shown that in about 7% of the recorded events a large rapidity gap of at least 3 units is observed between the proton direction and the observed hadronic system. The observation can be understood in terms of soft photon-hadron reactions, where the hadronic final state is interpreted as arising from the dissociation of a virtual photon in the field of a diffractively scattered proton. The cross section of this process can be expressed in terms of the diffractive structure function of the proton. Here a measurement with the ZEUS detector is presented of the diffractive structure function of the proton as a function of x IP , the momentum fraction lost by the proton, of β, the momentum fraction of the struck constituent with respect to x IP , and of Q 2 , the virtuality of the exchanged photon. The kinematic range of this measurement is 6.3.10 -4 IP -2 , 0.1 2 2 2 . The x IP dependence is consistent with the form (1/x IP ) a where a=1.30±0.08(stat) -0.14 +0.08 (sys) in all bins of β and Q 2 . The diffractive structure function scales with Q 2 at fixed β. The results are compared with theoretical predictions of diffractive dissociation in deep inelastic scattering. (orig.)

  11. Measurement of D{sup {+-}} production in deep inelastic ep scattering with the ZEUS detector at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max Planck Institute for Physics, Munich (Germany); Abt, I. [Max Planck Institute for Physics, Munich (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Krakow (Poland). Faculty of Physics and Applied Computer Science] [and others; Collaboration: ZEUS Collaboration

    2013-02-15

    Charm production in deep inelastic ep scattering was measured with the ZEUS detector using an integrated luminosity of 354 pb{sup -1}. Charm quarks were identified by reconstructing D{sup {+-}} mesons in the D{sup {+-}}{yields}K{sup -+}{pi}{sup {+-}}{pi}{sup {+-}} decay channel. Lifetime information was used to reduce combinatorial background substantially. Differential cross sections were measured in the kinematic region 5

  12. NLO Vertex for a Forward Jet plus a Rapidity Gap at High Energies

    CERN Document Server

    Hentschinski, Martin; Murdaca, Beatrice; Vera, Agustín Sabio

    2015-01-01

    We present the calculation of the forward jet vertex associated to a rapidity gap (coupling of a hard pomeron to the jet) in the BFKL formalism at next-to-leading order (NLO). Real emission contributions are computed via Lipatov's effective action. The NLO jet vertex turns out to be finite within collinear factorization and allows, together with the NLO non-forward gluon Green's function, to perform NLO studies of jet production in diffractive events (e.g. Mueller-Tang dijets).

  13. What can we learn from sum rules for vertex functions in QCD

    International Nuclear Information System (INIS)

    Craigie, N.S.; Stern, J.

    1982-04-01

    We demonstrate that the light cone sum rules for vertex functions based on the operator product expansion and QCD perturbation theory lead to interesting relationships between various non-perturbative parameters associated with hadronic bound states (e.g. vertex couplings and decay constants). We also show that such sum rules provide a valuable means of estimating the matrix elements of the higher spin operators in the meson wave function. (author)

  14. Pion-nucleon vertex function with an off-shell nucleon

    International Nuclear Information System (INIS)

    Nutt, W.T.; Shakin, C.M.

    1977-01-01

    A model calculation for the π-N vertex function is presented in the case in which there is a single off-mass-shell nucleon and a (nearly) on-mass-shell pion. Very strong effects due to the P 11 resonance at 1470 MeV are found. A simple parametrization of the vertex function is prvided in the case that at least one nucleon is on its mass shell. (Auth.)

  15. Studies of the Triple Pomeron Vertex in perturbative QCD and its applications in phenomenology

    International Nuclear Information System (INIS)

    Kutak, K.

    2006-12-01

    We study the properties of the Triple Pomeron Vertex in the perturbative QCD using the twist expansion method. Such analysis allows us to find the momenta configurations preferred by the vertex. When the momentum transfer is zero, the dominant contribution in the limit when N c →∞ comes from anticollinear pole. This is in agreement with result obtained without expanding, but by direct averaging of the Triple Pomeron Vertex over angles. Resulting theta functions show that the anticollinear configuration is optimal for the vertex. In the finite N c case the collinear term also contributes. Using the Triple Pomeron Vertex we construct a pomeron loop and we also consider four gluon propagation between two Triple Pomeron Vertices. We apply the Triple Pomeron Vertex to construct the Hamiltonian from which we derive the Balitsky-Kovchegov equation for an unintegrated gluon density. In order to apply this equation to phenomenology, we apply the Kwiecinski-Martin-Stasto model for higher order corrections to a linear part of the Balitsky-Kovchegov equation. We introduce the definition of the saturation scale which reflects properties of this equation. Finally, we use it for computation of observables, such as the F 2 structure function and diffractive Higgs boson production cross section. The impact of screening corrections on F 2 is negligible, but those effects turn out to be significant for diffractive Higgs boson production at LHC

  16. Studies of the Triple PomeronVertex in perturbative QCD and its applications in phenomenology

    Energy Technology Data Exchange (ETDEWEB)

    Kutak, K.

    2006-12-15

    We study the properties of the Triple Pomeron Vertex in the perturbative QCD using the twist expansion method. Such analysis allows us to find the momenta configurations preferred by the vertex. When the momentum transfer is zero, the dominant contribution in the limit when N{sub c}{yields}{infinity} comes from anticollinear pole. This is in agreement with result obtained without expanding, but by direct averaging of the Triple Pomeron Vertex over angles. Resulting theta functions show that the anticollinear configuration is optimal for the vertex. In the finite N{sub c} case the collinear term also contributes. Using the Triple Pomeron Vertex we construct a pomeron loop and we also consider four gluon propagation between two Triple Pomeron Vertices. We apply the Triple Pomeron Vertex to construct the Hamiltonian from which we derive the Balitsky-Kovchegov equation for an unintegrated gluon density. In order to apply this equation to phenomenology, we apply the Kwiecinski-Martin-Stasto model for higher order corrections to a linear part of the Balitsky-Kovchegov equation. We introduce the definition of the saturation scale which reflects properties of this equation. Finally, we use it for computation of observables, such as the F{sub 2} structure function and diffractive Higgs boson production cross section. The impact of screening corrections on F{sub 2} is negligible, but those effects turn out to be significant for diffractive Higgs boson production at LHC.

  17. Vertex dynamics in multi-soliton solutions of Kadomtsev–Petviashvili II equation

    International Nuclear Information System (INIS)

    Zarmi, Yair

    2014-01-01

    A functional of the solution of the Kadomtsev–Petviashvili II equation maps multi-soliton solutions onto systems of vertices—structures that are localized around soliton junctions. A solution with one junction is mapped onto a single vertex, which emulates a free, spatially extended, particle. In solutions with several junctions, each junction is mapped onto a vertex. Moving in the x–y plane, the vertices collide, coalesce upon collision and then split up. When well separated, they emulate free particles. Multi-soliton solutions, whose structure does not change under space–time inversion as |t| → ∞, are mapped onto vertex systems that undergo elastic collisions. Solutions, whose structure does change, are mapped onto systems that undergo inelastic collisions. The inelastic vertex collisions generated from the infinite family of (M,1) solutions (M external solitons, (M − 2) Y-shaped soliton junctions, M ⩾ 4) play a unique role: the only definition of vertex mass consistent with momentum conservation in these collisions is the spatial integral of the vertex profile. This definition ensures, in addition, that, in these collisions, the total mass and kinetic energy due to the motion in the y-direction are conserved. In general, the kinetic energy due to the motion in the x-direction is not conserved in these collisions. (paper)

  18. TECHNICAL DESIGN REPORT OF THE FORWARD SILICON VERTEX (FVTX)

    Energy Technology Data Exchange (ETDEWEB)

    PHENIX EXPERIMENT; OBRIEN,E.; PAK, R.; DREES, K.A.; (PHENIX EXPERIMENT COLLABORATORS)

    2007-08-01

    The main goal of the RHIC heavy ion program is the discovery of the novel ultra-hot high-density state of matter predicted by the fundamental theory of strong interactions and created in collisions of heavy nuclei, the Quark-Gluon Plasma (QGP). From measurements of the large elliptic flow of light mesons and baryons and their large suppression at high transverse momentum pT that have been made at RHIC, there is evidence that new degrees of freedom, characteristic of a deconfined QCD medium, drive the dynamics of nucleus-nucleus collisions. It has been recognized, however, that the potential of light quarks and gluons to characterize the properties of the QGP medium is limited and the next phase of the RHIC program calls for the precise determination of its density, temperature, opacity and viscosity using qualitatively new probes, such as heavy quarks. We propose the construction of two Forward Silicon Vertex Trackers (FVTX) for the PHENIX experiment that will directly identify and distinguish charm and beauty decays within the acceptance of the muon spectrometers. The FVTX will provide this essential coverage over a range of forward and backward rapidities (1.2 < |y| < 2.4)--a rapidity range coverage which not only brings significantly larger acceptance to PHENIX but which is critical for separating cold nuclear matter effects from QGP effects and is critical for measuring the proton spin contributions over a significant fraction of the kinematic range of interest. In addition, the FVTX will provide greatly reduced background and improved mass resolution for dimuon events, culminating in the first measurements of the {upsilon}{prime} and Drell-Yan at RHIC. These same heavy flavor and dimuon measurements in p+p collisions will allow us to place significant constraints on the gluon and sea quark contributions to the proton's spin and to make fundamentally new tests of the Sivers function universality.

  19. TECHNICAL DESIGN REPORT OF THE FORWARD SILICON VERTEX (FVTX)

    International Nuclear Information System (INIS)

    PHENIX EXPERIMENT; OBRIEN, E.; PAK, R.; DREES, K.A.

    2007-01-01

    The main goal of the RHIC heavy ion program is the discovery of the novel ultra-hot high-density state of matter predicted by the fundamental theory of strong interactions and created in collisions of heavy nuclei, the Quark-Gluon Plasma (QGP). From measurements of the large elliptic flow of light mesons and baryons and their large suppression at high transverse momentum pT that have been made at RHIC, there is evidence that new degrees of freedom, characteristic of a deconfined QCD medium, drive the dynamics of nucleus-nucleus collisions. It has been recognized, however, that the potential of light quarks and gluons to characterize the properties of the QGP medium is limited and the next phase of the RHIC program calls for the precise determination of its density, temperature, opacity and viscosity using qualitatively new probes, such as heavy quarks. We propose the construction of two Forward Silicon Vertex Trackers (FVTX) for the PHENIX experiment that will directly identify and distinguish charm and beauty decays within the acceptance of the muon spectrometers. The FVTX will provide this essential coverage over a range of forward and backward rapidities (1.2 < |y| < 2.4)--a rapidity range coverage which not only brings significantly larger acceptance to PHENIX but which is critical for separating cold nuclear matter effects from QGP effects and is critical for measuring the proton spin contributions over a significant fraction of the kinematic range of interest. In addition, the FVTX will provide greatly reduced background and improved mass resolution for dimuon events, culminating in the first measurements of the υ(prime) and Drell-Yan at RHIC. These same heavy flavor and dimuon measurements in p+p collisions will allow us to place significant constraints on the gluon and sea quark contributions to the proton's spin and to make fundamentally new tests of the Sivers function universality

  20. Micro Vision

    OpenAIRE

    Ohba, Kohtaro; Ohara, Kenichi

    2007-01-01

    In the field of the micro vision, there are few researches compared with macro environment. However, applying to the study result for macro computer vision technique, you can measure and observe the micro environment. Moreover, based on the effects of micro environment, it is possible to discovery the new theories and new techniques.

  1. Vertex Stimulation as a Control Site for Transcranial Magnetic Stimulation: A Concurrent TMS/fMRI Study

    OpenAIRE

    Jung, JeYoung; Bungert, Andreas; Bowtell, Richard; Jackson, Stephen R.

    2016-01-01

    Background A common control condition for transcranial magnetic stimulation (TMS) studies is to apply stimulation at the vertex. An assumption of vertex stimulation is that it has relatively little influence over on-going brain processes involved in most experimental tasks, however there has been little attempt to measure neural changes linked to vertex TMS. Here we directly test this assumption by using a concurrent TMS/fMRI paradigm in which we investigate fMRI blood-oxygenation-level-depen...

  2. A silicon pixel detector prototype for the CLIC vertex detector

    CERN Multimedia

    AUTHOR|(INSPIRE)INSPIRE-00714258

    2017-01-01

    A silicon pixel detector prototype for CLIC, currently under study for the innermost detector surrounding the collision point. The detector is made of a High-Voltage CMOS sensor (top) and a CLICpix2 readout chip (bottom) that are glued to each other. Both parts have a size of 3.3 x 4.0 $mm^2$ and consist of an array of 128 x 128 pixels of 25 x 25 $\\micro m^2$ size.

  3. Law of large numbers for the SIR model with random vertex weights on Erdős-Rényi graph

    Science.gov (United States)

    Xue, Xiaofeng

    2017-11-01

    In this paper we are concerned with the SIR model with random vertex weights on Erdős-Rényi graph G(n , p) . The Erdős-Rényi graph G(n , p) is generated from the complete graph Cn with n vertices through independently deleting each edge with probability (1 - p) . We assign i. i. d. copies of a positive r. v. ρ on each vertex as the vertex weights. For the SIR model, each vertex is in one of the three states 'susceptible', 'infective' and 'removed'. An infective vertex infects a given susceptible neighbor at rate proportional to the production of the weights of these two vertices. An infective vertex becomes removed at a constant rate. A removed vertex will never be infected again. We assume that at t = 0 there is no removed vertex and the number of infective vertices follows a Bernoulli distribution B(n , θ) . Our main result is a law of large numbers of the model. We give two deterministic functions HS(ψt) ,HV(ψt) for t ≥ 0 and show that for any t ≥ 0, HS(ψt) is the limit proportion of susceptible vertices and HV(ψt) is the limit of the mean capability of an infective vertex to infect a given susceptible neighbor at moment t as n grows to infinity.

  4. The MAPS based PXL vertex detector for the STAR experiment

    Science.gov (United States)

    Contin, G.; Anderssen, E.; Greiner, L.; Schambach, J.; Silber, J.; Stezelberger, T.; Sun, X.; Szelezniak, M.; Vu, C.; Wieman, H.; Woodmansee, S.

    2015-03-01

    The Heavy Flavor Tracker (HFT) was installed in the STAR experiment for the 2014 heavy ion run of RHIC. Designed to improve the vertex resolution and extend the measurement capabilities in the heavy flavor domain, the HFT is composed of three different silicon detectors based on CMOS monolithic active pixels (MAPS), pads and strips respectively, arranged in four concentric cylinders close to the STAR interaction point. The two innermost HFT layers are placed at a radius of 2.7 and 8 cm from the beam line, respectively, and accommodate 400 ultra-thin (50 μ m) high resolution MAPS sensors arranged in 10-sensor ladders to cover a total silicon area of 0.16 m2. Each sensor includes a pixel array of 928 rows and 960 columns with a 20.7 μ m pixel pitch, providing a sensitive area of ~ 3.8 cm2. The architecture is based on a column parallel readout with amplification and correlated double sampling inside each pixel. Each column is terminated with a high precision discriminator, is read out in a rolling shutter mode and the output is processed through an integrated zero suppression logic. The results are stored in two SRAM with ping-pong arrangement for a continuous readout. The sensor features 185.6 μ s readout time and 170 mW/cm2 power dissipation. The detector is air-cooled, allowing a global material budget as low as 0.39% on the inner layer. A novel mechanical approach to detector insertion enables effective installation and integration of the pixel layers within an 8 hour shift during the on-going STAR run.In addition to a detailed description of the detector characteristics, the experience of the first months of data taking will be presented in this paper, with a particular focus on sensor threshold calibration, latch-up protection procedures and general system operations aimed at stabilizing the running conditions. Issues faced during the 2014 run will be discussed together with the implemented solutions. A preliminary analysis of the detector performance

  5. The MAPS based PXL vertex detector for the STAR experiment

    International Nuclear Information System (INIS)

    Contin, G.; Anderssen, E.; Greiner, L.; Silber, J.; Stezelberger, T.; Vu, C.; Wieman, H.; Woodmansee, S.; Schambach, J.; Sun, X.; Szelezniak, M.

    2015-01-01

    The Heavy Flavor Tracker (HFT) was installed in the STAR experiment for the 2014 heavy ion run of RHIC. Designed to improve the vertex resolution and extend the measurement capabilities in the heavy flavor domain, the HFT is composed of three different silicon detectors based on CMOS monolithic active pixels (MAPS), pads and strips respectively, arranged in four concentric cylinders close to the STAR interaction point. The two innermost HFT layers are placed at a radius of 2.7 and 8 cm from the beam line, respectively, and accommodate 400 ultra-thin (50 μ m) high resolution MAPS sensors arranged in 10-sensor ladders to cover a total silicon area of 0.16 m 2 . Each sensor includes a pixel array of 928 rows and 960 columns with a 20.7 μ m pixel pitch, providing a sensitive area of ∼ 3.8 cm 2 . The architecture is based on a column parallel readout with amplification and correlated double sampling inside each pixel. Each column is terminated with a high precision discriminator, is read out in a rolling shutter mode and the output is processed through an integrated zero suppression logic. The results are stored in two SRAM with ping-pong arrangement for a continuous readout. The sensor features 185.6 μ s readout time and 170 mW/cm 2 power dissipation. The detector is air-cooled, allowing a global material budget as low as 0.39% on the inner layer. A novel mechanical approach to detector insertion enables effective installation and integration of the pixel layers within an 8 hour shift during the on-going STAR run.In addition to a detailed description of the detector characteristics, the experience of the first months of data taking will be presented in this paper, with a particular focus on sensor threshold calibration, latch-up protection procedures and general system operations aimed at stabilizing the running conditions. Issues faced during the 2014 run will be discussed together with the implemented solutions. A preliminary analysis of the detector

  6. Automatised data quality monitoring of the LHCb Vertex Locator

    Science.gov (United States)

    Bel, L.; Crocombe, A. Ch.; Gersabeck, M.; Pearce, A.; Majewski, M.; Szumlak, T.

    2017-10-01

    The LHCb Vertex Locator (VELO) is a silicon strip semiconductor detector operating at just 8mm distance to the LHC beams. Its 172,000 strips are read at a frequency of 1.1 MHz and processed by off-detector FPGAs followed by a PC cluster that reduces the event rate to about 10 kHz. During the second run of the LHC, which lasts from 2015 until 2018, the detector performance will undergo continued change due to radiation damage effects. This necessitates a detailed monitoring of the data quality to avoid adverse effects on the physics analysis performance. The VELO monitoring infrastructure has been re-designed compared to the first run of the LHC when it was based on manual checks. The new system is based around an automatic analysis framework, which monitors the performance of new data as well as long-term trends and using dedicated algorithms flags issues whenever they arise. The new analysis framework then analyses the plots that are produced by these algorithms. One of its tasks is to perform custom comparisons between the newly processed data and that from reference runs. The most-likely scenario in which this analysis would identify an issue is the parameters of the readout electronics no longer being optimal and requiring retuning. The data of the monitoring plots can be reduced further, e.g. by evaluating averages, and these quantities are input to long-term trending. This is used to detect slow variation of quantities, which are not detectable by the comparison of two nearby runs. Such gradual change is what is expected due to radiation damage effects. It is essential to detect these changes early such that measures can be taken, e.g. adjustments of the operating voltage, to prevent any impact on the quality of high-level quantities and thus on physics analyses. The plots as well as the analysis results and trends are made available through graphical user interfaces (GUIs). These GUIs are dynamically configured by a single configuration that determines the

  7. Introduction to vertex algebras, Borcherds algebras and the Monster Lie algebras

    International Nuclear Information System (INIS)

    Gebert, R.W.

    1993-09-01

    The theory of vertex algebras constitutes a mathematically rigorous axiomatic formulation of the algebraic origins of conformal field theory. In this context Borcherds algebras arise as certain ''physical'' subspaces of vertex algebras. The aim of this review is to give a pedagogical introduction into this rapidly-developing area of mathematics. Based on the machinery of formal calculus we present the axiomatic definition of vertex algebras. We discuss the connection with conformal field theory by deriving important implications of these axioms. In particular, many explicit calculations are presented to stress the eminent role of the Jacobi identity axiom for vertex algebras. As a class of concrete examples the vertex algebras associated with even lattices are constructed and it is shown in detail how affine Lie algebras and the fake Monster Lie algebra naturally appear. This leads us to the abstract definition of Borcherds algebras as generalized Kac-Moody algebras and their basic properties. Finally, the results about the simplest generic Borcherds algebras are analysed from the point of view of symmetry in quantum theory and the construction of the Monster Lie algebra is sketched. (orig.)

  8. [Umbilical blood-gas status at cesarean section for breech presentation: a comparison with vertex presentation].

    Science.gov (United States)

    Haruta, M; Saeki, N; Naka, Y; Funato, T; Ohtsuki, Y

    1989-10-01

    Umbilical blood-gas status at elective cesarean section with oxygen inhalation for breech presentation (25 cases) was compared with that for vertex presentation (25 cases), so as to confirm the security of full-term breech fetuses delivered by cesarean section under spinal anesthesia. Umbilical arterial oxygen levels were significantly lower in the breech group (Mean PO2:18.9 mmHg; SO2:37.3%; Oxygen content:7.6 ml/dl). The number of hypoxemic fetuses was significantly higher in the breech group (the breech: 7; the vertex; 0). The other umbilical blood-gas values revealed no significant differences between the breech and vertex groups, and were within normal limits in both groups. Oxygen extraction in the breech (Mean: 49.0%) was higher than that in the vertex (32.9%). Therefore decreased umbilical blood flow in the breech was suggested. The incidence of depression at 1 minute after delivery in the breech infants (24%) was significantly higher than that in the vertex infants (0%). It became obvious in the breech that as the interval between the uterine incision and delivery increased, umbilical arterial blood tended to acidosis and the 1 minute Apgar score decreased. Cesarean section for breech presentation requires sufficient and optimal incisions of the abdominal wall and uterus as well as a skillful manual delivery technique, because the fetus or neonate should be protected against asphyxia resulting from umbilical compression and prolonged delivery interval.

  9. Meson-baryon-baryon vertex function and the Ward-Takahashi identity

    International Nuclear Information System (INIS)

    Wang, S.; Banerjee, M.K.

    1996-01-01

    Ohta proposed a solution for the well-known difficulty of satisfying the Ward-Takahashi identity for a photo-meson-baryon-baryon amplitude (γMBB) when a dressed meson-baryon-baryon (MBB) vertex function is present. He obtained a form for the γMBB amplitude which contained, in addition to the usual pole terms, longitudinal seagull terms which were determined entirely by the MBB vertex function. He arrived at his result by using a Lagrangian which yields the MBB vertex function at tree level. We show that such a Lagrangian can be neither Hermitian nor charge conjugation invariant. We have been able to reproduce Ohta close-quote s result for the γMBB amplitude using the Ward-Takahashi identity and no other assumption, dynamical or otherwise, and the most general form for the MBB and γMBB vertices. However, contrary to Ohta close-quote s finding, we find that the seagull terms are not robust. The seagull terms extracted from the γMBB vertex occur unchanged in tree graphs, such as in an exchange current amplitude. But the seagull terms which appear in a loop graph, as in the calculation of an electromagnetic form factor, are, in general, different. The whole procedure says nothing about the transverse part of the (γMBB) vertex and its contributions to the amplitudes in question. copyright 1996 The American Physical Society

  10. Chiral vertex operators in off-conformal theory: Sine-Gordon example

    International Nuclear Information System (INIS)

    Chang, S.; Rajaraman, R.

    1996-01-01

    We study chiral vertex operators in sine-Gordon (SG) theory, viewed as an off-conformal system. We find that these operators, which would have been primary fields in the conformal limit, have interesting properties in the SG model. Some of them commute with the cosine interaction term in the Hamiltonian at a finite separation. Their Heisenberg equations of motion are local in space. An example of such vertex operators is Mandelstam close-quote s bosonic representation of the Fermi field. Another example is a set of vertex operators of topological number 2. We show how to construct conserved nonlocal currents from these operators. In the presence of the nonconformal interactions, these nonlocal currents have unique Lorentz spins. copyright 1996 The American Physical Society

  11. The Yang-Baxter equation for PT invariant 19-vertex models

    International Nuclear Information System (INIS)

    Pimenta, R A; Martins, M J

    2011-01-01

    We study the solutions of the Yang-Baxter equation associated with 19-vertex models invariant by the parity-time symmetry from the perspective of algebraic geometry. We determine the form of the algebraic curves constraining the respective Boltzmann weights and find that they possess a universal structure. This allows us to classify the integrable manifolds into four different families reproducing three known models, besides uncovering a novel 19-vertex model in a unified way. The introduction of the spectral parameter on the weights is made via the parameterization of the fundamental algebraic curve which is a conic. The diagonalization of the transfer matrix of the new vertex model and its thermodynamic limit properties are discussed. We point out a connection between the form of the main curve and the nature of the excitations of the corresponding spin-1 chains.

  12. A new efficient RLF-like algorithm for the vertex coloring problem

    Directory of Open Access Journals (Sweden)

    Adegbindin Mourchid

    2016-01-01

    Full Text Available The Recursive Largest First (RLF algorithm is one of the most popular greedy heuristics for the vertex coloring problem. It sequentially builds color classes on the basis of greedy choices. In particular, the first vertex placed in a color class C is one with a maximum number of uncolored neighbors, and the next vertices placed in C are chosen so that they have as many uncolored neighbors which cannot be placed in C. These greedy choices can have a significant impact on the performance of the algorithm, which explains why we propose alternative selection rules. Computational experiments on 63 difficult DIMACS instances show that the resulting new RLF-like algorithm, when compared with the standard RLF, allows to obtain a reduction of more than 50% of the gap between the number of colors used and the best known upper bound on the chromatic number. The new greedy algorithm even competes with basic metaheuristics for the vertex coloring problem.

  13. Status of vertex and tracking detector R&D at CLIC

    CERN Document Server

    AUTHOR|(SzGeCERN)754272

    2015-01-01

    The physics aims at the future CLIC high-energy linear e+e- collider set very high precision requirements on the performance of the vertex and tracking detectors. Moreover, these detectors have to be well adapted to the experimental conditions, such as the bunch train structure of the beam and the presence of beam-induced backgrounds. The principal challenges are: a point resolution of a few micron, ultra-low mass (~0.2% X0 per layer for the inner vertex region), very low power dissipation (compatible with air-flow cooling in the inner vertex region) and pulsed power operation, complemented with ~10 ns time stamping capabilities. An overview of the R&D program for pixel and tracking detectors at CLIC will be presented, including recent results on an innovative hybridisation concept based on capacitive coupling between active sensors (HV-CMOS) and readout ASICs (CLICpix).

  14. VXD3: The SLD vertex detector upgrade based on a 307 Mpixel CCD system

    International Nuclear Information System (INIS)

    1995-07-01

    The SLD Collaboration is building a new CCD vertex detector (VXD3) comprising 96 3.2 Mpixel CCDs of 13 cm 2 each for a total of 307 million pixels. This system is an upgrade of the Pioneering CCD vertex detector VXD2 which has operated in SLD since 1992. The CCDs of VXD3 are mounted on beryllium ladders in three cylinders, providing three space point measurements along each track of about 5 microns resolution in all three coordinates. The design and construction of VXD3 builds on three years of successful performance of VXD2. Significant improvements are achieved with VXD3 in impact parameters resolution (about a factor of two) and acceptance (∼20%) through optimized geometry and reduced material. New readout electronics have been developed for this system. This new vertex detector will be installed in late 1995 for the future runs of SLD

  15. Measurement of the charm and beauty structure functions using the H1 vertex detector at HERA

    International Nuclear Information System (INIS)

    Aaron, F.D.; Alexa, C.; Preda, T.; Rotaru, M.; Stoicea, G.; Zus, R.; Aldaya Martin, M.; Alimujiang, K.; Antunovic, B.; Bartel, W.; Brandt, G.; Campbell, A.J.; Cholewa, A.; Deak, M.; Boer, Y. de; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Glazov, A.; Gouzevitch, M.; Grell, B.R.; Haidt, D.; Helebrant, C.; Janssen, M.E.; Jung, H.; Katzy, J.; Kleinwort, C.; Knutsson, A.; Kraemer, M.; Krastev, K.; Kutak, K.; Levonian, S.; Lipka, K.; List, J.; Marti, L.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michels, V.; Niebuhr, C.; Nikiforov, A.; Nozicka, M.; Olsson, J.E.; Panagoulias, I.; Papadopoulou, T.; Pitzl, D.; Placakyte, R.; Radescu, V.; Rurikova, Z.; Schmitt, S.; Schoeffel, L.; Sefkow, F.; Staykova, Z.; Steder, M.; Vargas Trevino, A.; Vinokurova, S.; Driesch, M. von den; Wissing, C.; Wuensch, E.; Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Loktionova, N.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y.; Asmone, A.; Stella, B.; Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N.; Baghdasaryan, A.; Ghazaryan, S.; Volchinski, V.; Zohrabyan, H.; Barrelet, E.; Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B.; Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Li, G.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F.; Boudry, V.; Moreau, F.; Specka, A.; Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I.; Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Shaw-West, R.N.; Thompson, P.D.; Brinkmann, M.; Habib, S.; List, B.; Pokorny, B.; Toll, T.; Bruncko, D.; Cerny, V.; Ferencei, J.; Murin, P.; Tomasz, F.; Bunyatyan, A.; Buschhorn, G.; Chekelian, V.; Dossanov, A.; Grindhammer, G.; Kiesling, C.; Kogler, R.; Liptaj, A.; Olivier, B.; Raspiareza, A.; Shushkevich, S.; Bystritskaya, L.; Efremenko, V.; Fedotov, A.; Kropivnitskaya, A.; Lubimov, V.; Ozerov, D.; Petrukhin, A.; Rostovtsev, A.; Zhokin, A.; Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E.; Cassol-Brunner, F.; Diaconu, C.; Hoffmann, D.; Sauvan, E.; Trinh, T.N.; Vallee, C.; Cerny, K.; Pejchal, O.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Coughlan, J.A.; Morris, J.V.; Sankey, D.P.C.; Cozzika, G.; Feltesse, J.; Perez, E.; Cvach, J.; Reimer, P.; Zalesak, J.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kluge, T.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Rahmat, A.J.; Daum, K.; Meyer, H.; Del Degan, M.; Grab, C.; Leibenguth, G.; Sauter, M.; Zimmermann, T.; Delvax, J.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Marage, P.; Mozer, M.U.; Roland, B.; Roosen, R.; Sunar, D.; Sykora, T.; Mechelen, P. van; Dodonov, V.; Lytkin, L.; Povh, B.; Egli, S.; Hildebrandt, M.; Horisberger, R.; Falkiewicz, A.; Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J.; Glushkov, I.; Henschel, H.; Hiller, K.H.; Kostka, P.; Lange, W.; Naumann, T.; Piec, S.; Henderson, R.C.W.; Sloan, T.; Hennekemper, E.; Herbst, M.; Jung, A.W.; Krueger, K.; Lendermann, V.; Schultz-Coulon, H.C.; Urban, K.; Herrera, G.; Lopez-Fernandez, R.; Joensson, L.; Osman, S.; Kapichine, M.; Makankine, A.; Morozov, A.; Palichik, V.; Spaskov, V.; Tchoulakov, V.; Landon, M.P.J.; Rizvi, E.; Thompson, G.; Traynor, D.; Martyn, H.U.; Mueller, K.; Nowak, K.; Robmann, P.; Straumann, U.; Truoel, P.; Schoening, A.; South, D.; Wegener, D.; Tsakov, I.

    2010-01-01

    Inclusive charm and beauty cross sections are measured in e - p and e + p neutral current collisions at HERA in the kinematic region of photon virtuality 5≤Q 2 ≤2000 GeV 2 and Bjorken scaling variable 0.0002≤x≤0.05. The data were collected with the H1 detector in the years 2006 and 2007 corresponding to an integrated luminosity of 189 pb -1 . The numbers of charm and beauty events are determined using variables reconstructed by the H1 vertex detector including the impact parameter of tracks to the primary vertex and the position of the secondary vertex. The measurements are combined with previous data and compared to QCD predictions. (orig.)

  16. Cosmic ray test of the Belle II z-vertex trigger

    Energy Technology Data Exchange (ETDEWEB)

    Neuhaus, Sara; Skambraks, Sebastian [Technische Universitaet Muenchen (Germany); Chen, Yang; Kiesling, Christian [Max-Planck-Institut fuer Physik, Muenchen (Germany)

    2016-07-01

    The z-vertex trigger is part of the first level track trigger in the Belle II experiment. Its task is the rejection of tracks not coming from the interaction region, suppressing a large part of the machine background. Therefore the z-vertex trigger allows to relax other track trigger conditions and thus strongly increases the efficiency for channels with low track multiplicity (e.g. tau pair production). The track trigger works in several steps, first combining hits to track segments, followed by a 2D track finding in the transverse plane and finally the 3D reconstruction. Our method employs neural networks to estimate the z-vertex without explicit track reconstruction. For the first real test with cosmic rays special neural networks have been prepared. Although the track shape in the cosmic test is different than in the Belle II experiment, the neural networks require only a retraining with an appropriate data set to adapt to the new geometry.

  17. Modeling & Informatics at Vertex Pharmaceuticals Incorporated: our philosophy for sustained impact.

    Science.gov (United States)

    McGaughey, Georgia; Patrick Walters, W

    2017-03-01

    Molecular modelers and informaticians have the unique opportunity to integrate cross-functional data using a myriad of tools, methods and visuals to generate information. Using their drug discovery expertise, information is transformed to knowledge that impacts drug discovery. These insights are often times formulated locally and then applied more broadly, which influence the discovery of new medicines. This is particularly true in an organization where the members are exposed to projects throughout an organization, such as in the case of the global Modeling & Informatics group at Vertex Pharmaceuticals. From its inception, Vertex has been a leader in the development and use of computational methods for drug discovery. In this paper, we describe the Modeling & Informatics group at Vertex and the underlying philosophy, which has driven this team to sustain impact on the discovery of first-in-class transformative medicines.

  18. The elliptic quantum algebra Uq,p(sl-hatN) and its vertex operators

    International Nuclear Information System (INIS)

    Chang Wenjing; Ding Xiangmao

    2009-01-01

    We construct a realization of the elliptic quantum algebra U q,p (sl-hat N ) for any given level k in terms of free boson fields and their twisted partners. It can be considered as the elliptic deformation of the Wakimoto realization of the quantum affine algebra U q (sl-hat N ). We also construct a family of screening currents, which commute with the currents of U q,p (sl-hat N ) up to total q-differences. And we give explicit twisted expressions for the type I and type II vertex operators of U q,p (sl-hat N ) by twisting the known results of the type I vertex operators of the quantum affine algebra U q (sl-hat N ) and the new results of the type II vertex operators of U q (sl-hat N ) we obtained in this paper.

  19. Measurement of the Charm and Beauty Structure Functions using the H1 Vertex Detector at HERA

    CERN Document Server

    Aaron, FD; Alexa, C; Alimujiang, K; Andreev, V; Antunovic, B; Asmone, A; Backovic, S; Baghdasaryan, A; Barrelet, E; Bartel, W; Begzsuren, K; Belousov, A; Bizot, J C; Boudry, V; Bozovic-Jelisavcic, I; Bracinik, J; Brandt, G; Brinkmann, M; Brisson, V; Bruncko, D; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Cantun Avila, K B; Cassol-Brunner, F; Cerny, K; Cerny, V; Chekelian, V; Cholewa, A; Contreras, J G; Coughlan, J A; Cozzika, G; Cvach, J; Dainton, J B; Daum, K; Deak, M; de Boer, Y; Delcourt, B; Del Degan, M; Delvax, J; De Wolf, E A; Diaconu, C; Dodonov, V; Dossanov, A; Dubak, A; Eckerlin, G; Efremenko, V; Egli, S; Eliseev, A; Elsen, E; Falkiewicz, A; Favart, L; Fedotov, A; Felst, R; Feltesse, J; Ferencei, J; Fischer, D -J; Fleischer, M; Fomenko, A; Gabathuler, E; Gayler, J; Ghazaryan, Samvel; Glazov, A; Glushkov, I; Goerlich, L; Gogitidze, N; Gouzevitch, M; Grab, C; Greenshaw, T; Grell, B R; Grindhammer, G; Habib, S; Haidt, D; Helebrant, C; Henderson, R C W; Hennekemper, E; Henschel, H; Herbst, M; Herrera, G; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R; Hreus, T; Jacquet, M; Janssen, M E; Janssen, X; Jonsson, L; Jung, Andreas Werner; Jung, H; Kapichine, M; Katzy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Kluge, T; Knutsson, A; Kogler, R; Kostka, P; Kraemer, M; Krastev, K; Kretzschmar, J; Kropivnitskaya, A; Kruger, K; Kutak, K; Landon, M P J; Lange, W; Lastovicka-Medin, G; Laycock, P; Lebedev, A; Leibenguth, G; Lendermann, V; Levonian, S; Li, G; Lipka, K; Liptaj, A; List, B; List, J; Loktionova, N; Lopez-Fernandez, R; Lubimov, V; Lytkin, L; Makankine, A; Malinovski, E; Marage, P; Marti, Ll; Martyn, H -U; Maxfield, S J; Mehta, A; Meyer, A B; Meyer, H; Meyer, H; Meyer, J; Michels, V; Mikocki, S; Milcewicz-Mika, I; Moreau, F; Morozov, A; Morris, J V; Mozer, Matthias Ulrich; Mudrinic, M; Muller, K; Murin, P; Naumann, Th; Newman, P R; Niebuhr, C; Nikiforov, A; Nowak, G; Nowak, K; Nozicka, M; Olivier, B; Olsson, J E; Osman, S; Ozerov, D; Palichik, V; Panagoulias, I; Pandurovic, M; Papadopoulou, Th; Pascaud, C; Patel, G D; Pejchal, O; Perez, E; Petrukhin, A; Picuric, I; Piec, S; Pitzl, D; Placakyte, R; Pokorny, B; Polifka, R; Povh, B; Preda, T; Radescu, V; Rahmat, A J; Raicevic, N; Raspiareza, A; Ravdandorj, T; Reimer, P; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rotaru, M; Ruiz Tabasco, J E; Rurikova, Z; Rusakov, S; Salek, D; Sankey, D P C; Sauter, M; Sauvan, E; Schmitt, S; Schoeffel, L; Schoning, A; Schultz-Coulon, H -C; Sefkow, F; Shaw-West, R N; Shtarkov, L N; Shushkevich, S; Sloan, T; Smiljanic, Ivan; Soloviev, Y; Sopicki, P; South, D; Spaskov, V; Specka, Arnd E; Staykova, Z; Steder, M; Stella, B; Stoicea, G; Straumann, U; Sunar, D; Sykora, T; Tchoulakov, V; Thompson, G; Thompson, P D; Toll, T; Tomasz, F; Tran, T H; Traynor, D; Trinh, T N; Truol, P; Tsakov, I; Tseepeldorj, B; Turnau, J; Urban, K; Valkarova, A; Vallee, C; Van Mechelen, P; Vargas Trevino, A; Vazdik, Y; Vinokurova, S; Volchinski, V; von den Driesch, M; Wegener, D; Wissing, Ch; Wunsch, E; Zacek, J; Zalesak, J; Zhang, Z; Zhokin, A; Zimmermann, T; Zohrabyan, H; Zomer, F; Zus, R

    2010-01-01

    Inclusive charm and beauty cross sections are measured in e-p and e+p neutral current collisions at HERA in the kinematic region of photon virtuality 5vertex detector including the impact parameter of tracks to the primary vertex and the position of the secondary vertex. The measurements are combined with previous data and compared to QCD predictions.

  20. On the transfer matrix of the supersymmetric eight-vertex model. I. Periodic boundary conditions

    Science.gov (United States)

    Hagendorf, Christian; Liénardy, Jean

    2018-03-01

    The square-lattice eight-vertex model with vertex weights a, b, c, d obeying the relation (a^2+ab)(b^2+ab) = (c^2+ab)(d^2+ab) and periodic boundary conditions is considered. It is shown that the transfer matrix of the model for L  =  2n  +  1 vertical lines and periodic boundary conditions along the horizontal direction possesses the doubly degenerate eigenvalue \\Thetan = (a+b){\\hspace{0pt}}2n+1 . This proves a conjecture by Stroganov from 2001. The proof uses the supersymmetry of a related XYZ spin-chain Hamiltonian. The eigenstates of the transfer matrix corresponding to \\Thetan are shown to be the ground states of the spin-chain Hamiltonian. Moreover, for positive vertex weights \\Thetan is the largest eigenvalue of the transfer matrix.