The design and performance of the ZEUS micro vertex detector
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.)
Design and Tests of the Silicon Sensors for the ZEUS Micro Vertex Detector
Dannheim, D; Coldewey, C; Fretwurst, E; Garfagnini, A; Klanner, Robert; Martens, J; Koffeman, E; Tiecke, H G; 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 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 sensors with three different geometries have been produced by Hamamatsu Photonics K.K. Irradiation tests with reactor neutrons and Co-60 photons have been performed for a small sample of sensors. The results on neutron irradiation (with a fluence of 1 x 10^{13} 1 MeV equivalent neutrons / cm^2) are well described by empirical formulae for bulk damage. The Co-60 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 hol...
The ZEUS vertex detector: Design and prototype
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. (European Organization for Nuclear Research, Geneva (Switzerland) Bologna Univ. (Italy). Dipt. di Fisica Cosenza Univ. (Italy). Dipt. di Fisica Florence Univ. (Italy). Dipt. di Fisica Istituto Nazionale di Fisica Nucleare, Bologna (Italy) Istituto Nazionale di Fisica Nucleare, Florence (Italy) Istituto Nazionale di Fisica Nucleare, Frascati (Italy). Lab. Nazionale di Frascati Consiglio Nazionale delle Ricerche, Flore
1991-07-10
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 {mu}m and an average wire efficiency of 96% have been achieved, for a 3 mm gas gap relative to each sense wire. (orig.).
Vertex Reconstructing Neural Network at the ZEUS Central Tracking Detector
Dror, G; Dror, Gideon; Etzion, Erez
2001-01-01
An unconventional solution for finding the location of event creation is presented. It is based on two feed-forward neural networks with fixed architecture, whose parameters are chosen so as to reach a high accuracy. The interaction point location is a parameter that can be used to select events of interest from the very high rate of events created at the current experiments in High Energy Physics. The system suggested here is tested on simulated data sets of the ZEUS Central Tracking Detector, and is shown to perform better than conventional algorithms.
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.)
Arslan, Ozan; Brock, Ian C.; Mergelmeyer, Sebastian [University of Bonn (Germany)
2012-07-01
During the years 2005-2007, the e{sup {+-}}p-collider HERA was operated at a centre-of-mass energy of 320 GeV, and provided the ZEUS detector with an integrated luminosity of L{approx}300 pb{sup -1}. This analysis is based on photoproduction events, which are characterized by the emission of a quasi-real photon (Q{sup 2} < 1 GeV{sup 2}) from the incoming lepton. The subsequent {gamma}p-interaction is dominated by the process {gamma}g {yields}q anti q, where the two outgoing quarks give rise to two high-p{sub T} jets in the final state. The production of charm and beauty quarks was measured using the properties of their secondary vertices. Compared to similar previous analyses, the kinematic coverage was extended into the forward direction, the amount of data has been increased and the kinematics of the outgoing quarks and their correlations were investigated. The results are presented as total and differential cross sections, and compared to Monte Carlo simulations and theory predictions at next-to-leading order QCD.
Technical Design Report for the: PANDA Micro Vertex Detector
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
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.
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
Recent Results from the ZEUS Experiment
Smith, W H; Abramowicz, H; Adamczyk, L; Adamus, M; Adler, V; Aghuzumtsyan, G; Antonioli, P; Antonov, A; Arneodo, M; Bailey, D S; Bamberger, A; Barakbaev, A N; Barbagli, G; Barbi, M; Bari, G; Barreiro, F; Bartsch, D; Basile, M; Bauerdick, L A T; Behrens, U; Bell, M; Bellagamba, L; Benen, A; Bertolin, A; Bhadra, S; Bloch, I; Bodmann, B; Bold, T; Boos, E G; Borras, K; Boscherini, D; Brock, I; Brook, N H; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Bussey, P J; Butterworth, J M; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carli, T; Carlin, R; Catterall, C D; Chekanov, S; Chiochia, V; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, Luisa; Cindolo, F; Cloth, P; Cole, J E; Collins-Tooth, C; Contin, A; Cooper-Sarkar, A M; Coppola, N; Cormack, C; Corradi, M; Corriveau, F; Cottrell, A; D'Agostini, Giulio; Dal Corso, F; Danilov, P; Dannheim, D; De Pasquale, S; Dementiev, R K; Derrick, M; Deshpande, Abhay A; Devenish, R C E; Dhawan, S; Dolgoshein, B A; Doyle, A T; Drews, G; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, Andrzej; Ferrando, J; Ferrero, M I; Figiel, J; Filges, D; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fricke, U; Fusayasu, T; Gabareen, A; Gallo, E; Garfagnini, A; Geiser, A; Genta, C; Gialas, I; Giusti, P; Gladilin, L K; Gladkov, D; Glasman, C; Gliga, S; Goers, S; Golubkov, Yu A; Goncalo, R; González, O; Göttlicher, P; Grabowska-Bold, I; Grijpink, S; Grzelak, G; Gutsche, O; Gwenlan, C; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hamilton, J; Hanlon, S; Hart, J C; Hartmann, H; Hartner, G; Hartner, G F; Heaphy, E A; Heath, G P; Heath, H F; Helbich, M; Heusch, C A; Hilger, E; Hillert, S; Hirose, T; Hochman, D; Holm, U; Iacobucci, G; Iga, Y; Inuzuka, M; Irrgang, P; Jakob, H P; Jones, T W; Kagawa, S; Kahle, B; Kaji, H; Kananov, S; Kappes, A; Kataoka, Y; Yamazaki, M; Katkov, I I; Katz, U F; Kcira, D; Khein, L A; Kim, J Y; Kim, Y K; Kind, O; Kisielewska, D; Kitamura, S; Klimek, K; Koffeman, E; Kohno, T; Kooijman, P; Koop, T; Korzhav, I A; Kotanski, A; Kötz, U; Kowal, A M; Kowal, M; Kowalski, H; Kowalski, T; Krakauer, D; Kramberger, G; Kreisel, A; Krumnack, N; Kuze, M; Kuzmin, V A; Labarga, L; Labes, H; Lainesse, J; Lammers, S; Lee, J H; Lee, S W; Lelas, D; Levchenko, B B; Levman, G M; Levy, A; Li, L; Lightwood, M S; Lim, H; Lim, I T; Limentani, S; Ling, T Y; Liu, X; Löhr, B; Lohrmann, E; Loizides, J H; Long, K R; Longhin, A; Lukina, O Yu; Lupi, A; Luzniak, P; Maddox, E; Magill, S; Mankel, R; Margotti, A; Marini, G; Martin, J F; Mastroberardino, A; Matsuzawa, K; Mattingly, M C K; McCubbin, N A; Mellado, B; Melzer-Pellmann, I A; Menary, S R; Metlica, F; Meyer, U; Milite, M; Mirea, A; Monaco, V; Montanari, A; Moritz, M; Musgrave, B; Nagano, K; Nania, R; Nguyen, C N; Nigro, A; Ning, Y; Nishimura, T; Notz, D; Nowak, R J; Oh, B Y; Olkiewicz, K; Pac, M Y; Padhi, S; Paganis, S; Palmonari, F; Parenti, A; Park, I H; Patel, S; Paul, E; Pavel, N; Pawlak, J M; Pelfer, P G; Pellegrino, A; Pesci, A; Petrucci, M C; Piotrzkowski, K; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Posocco, M; Proskuryakov, A S; Przybycien, M B; Rautenberg, J; Raval, A; Reeder, D D; Ren, Z; Renner, R; Repond, J; Riveline, U; Karshon, M; Robins, S; Rodrigues, E; Rosin, M; Rurua, L; Ruspa, M; Sacchi, R; Salehi, H; Sartorelli, G; Savin, A A; Saxon, D H; Schagen, S; Schioppa, M; Schlenstedt, S; Schmidke, W B; Schneekloth, U; Sciulli, F; Scott, J; Selonke, F; Shcheglova, L M; Skillicorn, I O; Slominski, W; Soares, M; Solano, A; Son, D; Sosnovtsev, V V; Stairs, D G; Stanco, L; Standage, J; Stifutkin, A; Stoesslein, U; Stonjek, S; Stopa, P; Straub, P B; Suchkov, S; Susinno, G; Suszycki, L; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tandler, J; Tapper, A D; Tapper, R J; Tassi, E; Tawara, T; Terron, J; Tiecke, H G; Tokushuku, K; Tsurugai, T; Turcato, M; Tymieniecka, T; Ukleja, A; Ukleja, J; Vázquez, M; Velthuis, J J; Vlasov, N N; Voss, K C; Walczak, R; Walsh, R; Wang, M; Weber, A; Wessoleck, H; West, B J; Whitmore, J J; Wick, K; Wiggers, L; Wills, H H; Wing, M; Wolf, G; Yamada, S; Yamashita, T; Yoshida, R; Youngman, C; Zawiejski, L; Zeuner, W; Zhautykov, B O; Zichichi, A; Ziegler, A; Zotkin, S A; De Wolf, E; Del Peso, J
2004-01-01
A summary of recent results from ZEUS is presented. New ZEUS results from HERA-1 data include Structure Functions, QCD fits, analysis of hadronic final states, precision measurements of alpha_s, production of heavy flavor mesons and baryons and studies of diffraction. Results from the new HERA-II running include the measurement of the cross section for polarized charged current events and charm events tagged with the new ZEUS vertex detector.
The micro vertex detector for the anti PANDA experiment
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.
The design and performance of the ZEUS global tracking trigger
Allfrey, P. D.; Bell, M. A.; Coppola, N.; Devenish, R.; Dhawan, S.; Dunne, W.; Ferrando, J.; Gladkov, D.; Hall-Wilton, R.; Hayes, M.; Jakob, H.-P.; Loizidies, J. H.; Pellegrino, A.; Polini, A.; Roberfroid, V.; Soares, M.; Straub, P. B.; Stifutkin, A.; Sutton, M. R.; Topp-Jørgenssen, S.; West, B. J.; Woolley, N. P.; Youngman, C.
2007-10-01
The Global Tracking Trigger (GTT) of the ZEUS experiment is described. The GTT is data driven at the ZEUS first level trigger rate of ⩽600 Hz and performs event-based track finding on data from the experiment's Central Tracking Detector (CTD), silicon Micro Vertex Detector (MVD) and Straw Tube Tracker (STT) forward detectors. The resulting track-based trigger quantities calculated (track multiplicity, vertices, vector meson masses, background event probabilities, etc.) are available within ˜9 ms and are used in the experiment's second level trigger to improve the selection of physics events. Detector information is pushed to the PC farm of the GTT using PowerPC VME board computers which are either embedded within the detector's frontend readout system (MVD) or are parasitically attached to them via multiple serial transputer links (CTD and STT). Data flow and control is performed via point-to-point Fast and Giga ethernet switched network connections using the TCP protocol. The principal design challenges were: integrating new and interfacing to existing frontend systems, providing a useful trigger result, satisfying the rate and latency requirements and not interfering with ongoing data taking during commissioning. These aims have been achieved. The GTT has been actively used in the ZEUS trigger since 2004 when an initial CTD-only algorithm was used; in 2005 this was upgraded to use MVD information which significantly improves track and primary vertex resolutions. Commissioning problems delayed the STT implementation and its use in the GTT has only been tested.
Simulations with the PANDA micro-vertex-detector
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.
Garfagnini, A
1999-01-01
A new vertex detector for the ZEUS experiment at HERA will be installed during the 1999-2000 shutdown, for the high-luminosity runs of HERA. It will allow to reconstruct secondary vertex tracks, coming from the decay of long-lived particles with a lifetime of about 10 sup - sup 1 sup 2 s, and improve the global momentum resolution of the tracking system. The interaction region will be surrounded with single-sided silicon strip detectors, with capacitive charge division: three double layers in the central region (600 detectors), and 4 'wheels' in the forward region (112 silicon planes). Due to the high number of readout channels, 512 readout strips per silicon plane in the barrel region and 480 in the forward part, and the large coverage of the vertex detector (almost 1 m long), the front-end electronics has to be placed on top of the detectors and has to be radiation tolerant since doses up to 2 kGy are expected near the interaction region. The HELIX chip has been chosen as analog chip with a low-noise, charg...
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.)
The prototype of the Micro Vertex Detector of the CBM Experiment
Koziel, Michal, E-mail: Michal.Koziel@Physik.uni-frankfurt.de; Amar-Youcef, Samir; Bialas, Norbert; Deveaux, Michael; Fröhlich, Ingo; Li, Qiyan; Michel, Jan; Milanović, Borislav; Müntz, Christian; Neumann, Bertram; Schrader, Christoph; Stroth, Joachim; Tischler, Tobias; Weirich, Roland; Wiebusch, Michael
2013-12-21
The Compressed Baryonic Matter (CBM) Experiment is one of the core experiments of the future FAIR facility at Darmstadt, Germany. This fixed-target experiment will explore the phase diagram of strongly interacting matter in the regime of highest net baryon densities with numerous probes, among them open charm. Reconstructing those short lived particles requires a vacuum compatible Micro Vertex Detector (MVD) with unprecedented properties. Its sensor technology has to feature a spatial resolution of <5μm, a non-ionizing radiation tolerance of >10{sup 13}n{sub eq}/cm{sup 2}, an ionizing radiation tolerance of >3Mrad and a time resolution of a few 10μs. The MVD-prototype project aimed to study the integration the CMOS Monolithic Active Pixel Sensors foreseen for the MVD into an ultra light (0.3% X{sub 0}) and a vacuum compatible detector system based on a cooling support made of CVD-diamond.
Radiation hardness studies of epitaxial diodes for the PANDA micro-vertex-detector
Quagli, Tommaso; Brinkmann, Kai-Thomas; Schnell, Robert [II. Physikalisches Institut, Justus-Liebig-Universitaet Giessen, Giessen (Germany); Calvo, Daniela [INFN, Sezione di Torino, Torino (Italy); Collaboration: PANDA-Collaboration
2014-07-01
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 its innermost detector and is composed of four concentric barrels and six forward disks, instrumented with silicon hybrid pixel and double-sided microstrip detectors. It serves the identification of primary and secondary vertices. The main requirements include high spatial and time resolution, trigger-less readout with high rate capability, good radiation tolerance and low material budget. In order to investigate the radiation hardness of the silicon pixel sensors, irradiation studies were performed on diodes using a proton beam at the Bonn Isochronous Cyclotron. The diodes featured an epitaxial layer grown on a Czochralski substrate; the thicknesses of the epitaxial layers were 100μ m and 150μ m, respectively. Additionally, some of the samples were treated with an oxygenation process. The study was performed with two different fluences, comparing the I-V and C-V curves of the non-irradiated diodes with the ones obtained immediately after the irradiation and after an annealing phase.
Integration of the strip barrel staves of the PANDA micro vertex detector
Quagli, Tommaso; Brinkmann, Kai-Thomas; Schnell, Robert; Zaunick, Hans-Georg [II. Physikalisches Institut, Justus-Liebig-Universitaet Giessen, Giessen (Germany); Collaboration: PANDA-Collaboration
2014-07-01
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. Square and rectangular microstrip sensors will be used in the two outer barrels of the detector. The sensors and the front-end electronics will be arranged on linear staves, composed of a carbon support structure with an embedded active cooling system. A flexible multilayer bus will be used to route the signals on the stave towards the DAQ system. The design of the stave, its integration concept and some relevant hardware developments are presented.
Development of carbon fiber staves for the strip part of the PANDA micro vertex detector
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.
Development of a latch-up protection system for the Micro Vertex Detector of CBM
Koziel, Michal; Bialas, Norbert; Schrader, Christoph; Deveaux, Michael; Stroth, Joachim; Muentz, Christian [Institut fuer Kernphysik, Goethe-Universitaet, Frankfurt am Main (Germany); Seddiki, Selim [Institut Pluridisciplinaire Hubert Curien (IPHC), Strasbourg (France); Collaboration: CBM-MVD-Collaboration
2011-07-01
The Micro Vertex Detector (MVD) of the CBM experiment will be exposed to a high flux of various charge particles, among them nuclear fragments. The Linear Energy Transfer (LET) of such particles in the CMOS-sensors of the MVD is sufficient to generate latch-up and the latter was indeed seen in a beam tests carried out by the STAR HFT collaboration. This local short circuit is initiated when high, radiation induced charge carrier densities switch parasitic thyristors to the conductive state. The thyristor remains conductive until the power of the IC is cut and hence may cause permanent thermal damage in the device if not handled appropriately in short time. To protect the sensors of the MVD against such damage, we are developing a system, which detects the over-currents caused by the latch-up and protects affected sensors by means of a fast and controlled power cycle. The concept and implementation of this latch-up protection system are discussed.
A readout system for the micro-vertex-detector demonstrator for the CBM experiment at FAIR
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
Study of beauty photoproduction with the ZEUS experiment at the electron-proton collider HERA
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
Koziel, Michal; Bialas, Norbert; Milanovic, Borislaw [University of Frankfurt, Germany (Germany); Collaboration: CBM-MVD-Collaboration
2014-07-01
The Compressed Baryonic Matter experiment installed at the future FAIR facility will be equipped with a high-precision micro-vertex detector aiming at an outstanding primary and secondary vertex resolution. Highly granular, ultra-low material budget sensors, so-called Monolithic Active Pixel Sensors, manufactured at standard CMOS process, will be employed. Imperfections in CMOS process as well as further dicing and thinning procedures affect the yield of sensors to be mounted in the detector stations. To select sensors with the best characteristics, probe testing prior to integration is mandatory. handling and testing of 50-μm thin CMOS pixel sensors is non-standard. This contribution presents the dedicated tools and procedures, focusing on the question whether such thin devices can be efficiently and reliably probe-tested.
Design and performance studies of the micro-vertex-detector for the CBM experiment at FAIR
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
Micro channel evaporative $CO_2$ cooling for the upgrade of the LHCb vertex detector
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
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.
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
Koch, N; Kolanoski, H; Siegmund, T; Bergter, J; Eckstein, P; Schubert, Klaus R; Waldi, R; Imhof, M; Ressing, D; Weiss, U; Weseler, S
1995-01-01
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.
The ZEUS long term data preservation project
,
2016-01-01
The ZEUS data preservation (ZEUS DP) project assures continued access to the data and documentation related to the experiment. It aims to provide the ability to continue the generation of valuable scientific results from these data in the future. This talk presents analysis opportunities within the ZEUS DP project and its benefits for the physics community. The implications of the preserved data are discussed in the context of current data analyses, verification of contemporary and future theoretical models and the planning of future experiments and analyses. The detailed documentation on the data preservation effort can serve as an example for the data preservation efforts in current and future experiments.
The Zeus from Gaza re-examined
Ovadiah, Asher
1997-12-01
Full Text Available The re-examination of the monumental statue of Zeus from Gaza, nowadays exhibited in the Istanbul Archaeological Museums, comprises an iconographical, as well as a stylistic comparative analysis. Comparisons with monumental sculpture (Jupiter Verospi, Jupiter Otricoli, Capitoline Jupiter from Carthage, and the Zeus in the Metropolitan Museum of Art, statuettes, and other artistic media (vase painting, gems, coins indicate that this work of art shows an eclectic character of various artistic trends and concepts, based on Classical-Hellenistic features. It is plausible to conclude that the Zeus from Gaza is a Roman work of art, created by an anonymous artist and may be dated to the second century AD.Se realiza un nuevo examen, a través de análisis iconográfico y estilístico, de la estatua monumental del Zeus hallado en Gaza, hoy en el Museo Arqueológico de Estambul. Sus paralelos en escultura monumental, estatuillas y otros objetos artísticos —pintura vascular, gemas y monedas—, indican que esta obra de arte tiene un carácter ecléctico con tendencias varias y distintos conceptos artísticos de tipo clásico-helenístico. Es plausible concluir que tenemos en el Zeus de Gaza una obra romana anónima fechable en el siglo II d.C.
A QCD analysis of ZEUS diffractive data
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.)
Beauty in photoproduction at HERA II with the ZEUS detector
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.)
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)
Track and Vertex Reconstruction in CMS
Adam, W
2006-01-01
The CMS experiment relies on a Silicon pixel and micro-strip tracker for the reconstruction of tracks and vertices of charged particles in the harsh environment of proton and heavy-ion collisions at the LHC at CERN. An outline of the basic track and vertex reconstruction algorithms used in CMS is given and their performance is described. Results of more advanced algorithms like the Gaussian Sum Filter for electron reconstruction and robust vertex fitters are shown.
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.
Calibration of the ZEUS 6 m tagger
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.)
Chen, Li; Shen, Cencheng; Vogelstein, Joshua; Priebe, Carey
2013-01-01
For random graphs distributed according to stochastic blockmodels, a special case of latent position graphs, adjacency spectral embedding followed by appropriate vertex classification is asymptotically Bayes optimal; but this approach requires knowledge of and critically depends on the model dimension. In this paper, we propose a sparse representation vertex classifier which does not require information about the model dimension. This classifier represents a test vertex as a sparse combinatio...
The Zeus calorimeter first level trigger
Smith, W.J. [Univ. of Wisconsin, Madison, WI (United States)
1989-04-01
The design of the Zeus Detector Calorimeter Level Trigger is presented. The Zeus detector is being built for operation at HERA, a new storage ring that will provide collisions between 820 GeV protons and 30 GeV electrons in 1990. The calorimeter is made of depleted uranium plates and plastic scintillator read out by wavelength shifter bars into 12,864 photomultiplier tubes. These signals are combined into 974 trigger towers with separate electromagnetic and hadronic sums. The calorimeter first level trigger is pipelined with a decision provided 5 {mu}sec after each beam crossing, occurring every 96 nsec. The trigger 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 number and energy of clusters. The trigger rate needs to be held to 1 kHz against a rate of proton-beam gas interactions of approximately 500 kHz. The summed trigger tower pulseheights are digitized by flash ADC`s. The digital values are linearized, stored and used for sums and pattern tests.
Measurement of beauty quark production from dimuon events with the ZEUS detector at HERA II
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.)
Charm and Beauty Production from Secondary Vertexing at HERA
Thompson, Paul [University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom)
2010-07-01
Measurement of the Charm and Beauty Structure Functions using the H1 Vertex Detector at HERA Inclusive charm and beauty cross sections are measured in e{sup -} p and e{sup +}p neutral current collisions at HERA in the kinematic region of photon virtuality 5 < Q{sup 2} < 2000 GeV{sup 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{sup -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. Measurement of Charm and Beauty Jets in Deep Inelastic Scattering at HERA Measurements of the charm and beauty jet cross sections have been made in deep inelastic scattering at HERA for the kinematic region of photon virtuality Q{sup 2} > 6 GeV{sup 2} and elasticity variable 0.07 < y < 0.625 for jets in the laboratory frame with transverse energy E{sub T}{sup jet} > 6 GeV and pseudorapidity -1.0 < {eta}{sup jet} < 1.5. Measurements are also made requiring a jet in the Breit frame with E{sub T}{sup jet} > 6 GeV. The data were collected with the H1 detector in the years 2006 and 2007 corresponding to an integrated luminosity of 189 pb{sup -1}. The number of charm and beauty jets 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 compared with QCD predictions and with previous measurements obtained using muon tagging. Charm and beauty production in deep inelastic scattering from inclusive secondary vertexing at ZEUS Charm and beauty production in deep inelastic scattering has been measured with the ZEUS detector using the full HERA II data set. The charm and beauty contents
Wermes, Norbert
2006-01-01
Pixel vertex detectors are THE instrument of choice for the tracking of charged particles close to the interaction point at the LHC. Hybrid pixel detectors, in which sensor and read-out IC are separate entities, constitute the present state of the art in detector technology. Three of the LHC detectors use vertex detectors based on this technology. A development period of almost 10 years has resulted in pixel detector modules which can stand the extreme rate and timing requirements as well as ...
Zeus/Júpiter y Antiope en los Mosaicos Romanos
San Nicolás Pedraz, María Pilar
2010-01-01
... cronológico.In this paper we are going to examine the Roman mosaics with the representation of the myth of Zeus/Jupiter and Antiope in the various versions told by the literary sources, tackling both...
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.
Data acqusition for the Zeus central tracking detector
Quinton, S. [Rutherford Appleton Laboratory, Chilton (United Kingdom)
1989-04-01
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 SSC environment. This paper describes the Transputer based data acquisition for the Zeus Central Tracking Detector, and outlines some proposed development work on the use of parallel processing techniques in this field.
The LHCb Vertex Locator performance and Vertex Locator upgrade
INSPIRE-00259789
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 $\\rm \\mu$m. 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 MeV$\\rm n_{eq}/cm^2$, 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 $\\rm \\mu m$ 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...
Preparing ZEUS-2 for Observing Run at the APEX Telescope
Dahlin, Patrick; Vishwas, Amit; Nikola, Thomas; Stacey, Gordon J.
2017-01-01
ZEUS-2 is a direct detection grating spectrometer that was designed to maximize sensitivity for the detection of the far-infrared fine-structure lines from distant star forming galaxies as they are redshifted into the short submillimeter windows. ZEUS-2 employs two NIST TES bolometer arrays as its detector: one tuned to 400 μm and the other that consists of two sub-arrays, one tuned to 215 μm and the other tuned to 645 μm. Therefore, by placing bandpass filters directly above the detector ZEUS-2 can address four telluric windows (200 μm, 350 μm, 450 μm, and 650 μm) simultaneously on extended objects, and two windows (200 and 650 μm, or 350 and 450 μm) simultaneously on point sources. ZEUS-2 has now been deployed four times on the APEX telescope in Chile and demonstrated background limited performance both at 350 and 450 μm. As part of my NSF REU experience at Cornell in the summer of 2016, I helped with testing of ZEUS-2 in the lab and improving components for its use on the telescope. This poster will cover the principles of the ZEUS-2 instrument and some of the recent scientific results.
The Orbifold Topological Vertex
Bryan, Jim; Young, Ben
2010-01-01
We define Donaldson-Thomas invariants of Calabi-Yau orbifolds and we develop a topological vertex formalism for computing them. The basic combinatorial object is the orbifold vertex, a generating function for the number of 3D partitions asymptotic to three given 2D partitions and colored by representations of a finite Abelian group G acting on C^3. In the case where G=Z_n acting on C^3 with transverse A_{n-1} quotient singularities, we give an explicit formula for the vertex in terms of Schur functions. We discuss applications of our formalism to the Donaldson-Thomas Crepant Resolution Conjecture and to the orbifold Donaldson-Thomas/Gromov-Witten correspondence. We also explicitly compute the Donaldson-Thomas partition function for some simple orbifold geometries: the local football and the local BZ_2 gerbe.
Cohomological vertex operators
Viña, Andrés
2016-01-01
Given a Calabi-Yau manifold and considering the $B$-branes on it as objects in the derived category of coherent sheaves, we identify the vertex operators for strings between two branes with elements of the cohomology groups of Ext sheaves. We define the correlation functions for these general vertex operators. Strings stretching between two coherent sheaves are studied as homological extensions of the corresponding branes. In this context, we relate strings between different pairs of branes when there are maps between these branes. We also interpret some strings with ghost number $k$ as obstructions for lifts or extensions of strings with ghost number $k-1$.
Zeus/Júpiter y Antiope en los Mosaicos Romanos
María Pilar San Nicolás Pedraz
2010-01-01
Full Text Available Se realiza un estudio de los mosaicos romanos con la representación del mito de Zeus/Júpiter y Antiope en sus distintas versiones narradas por las fuentes literarias, abordando su contexto arqueológico y cronológico.In this paper we are going to examine the Roman mosaics with the representation of the myth of Zeus/Jupiter and Antiope in the various versions told by the literary sources, tackling both their archeological and chronological context.
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.
Further development of the ZEUS Expert System: Computer science foundations of design
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.)
Frühwirth, R; Vanlaer, Pascal
2007-01-01
Vertex fitting frequently has to deal with both mis-associated tracks and mis-measured track errors. A robust, adaptive method is presented that is able to cope with contaminated data. The method is formulated as an iterative re-weighted Kalman filter. Annealing is introduced to avoid local minima in the optimization. For the initialization of the adaptive filter a robust algorithm is presented that turns out to perform well in a wide range of applications. The tuning of the annealing schedule and of the cut-off parameter is described, using simulated data from the CMS experiment. Finally, the adaptive property of the method is illustrated in two examples.
Dannheim, D
2015-01-01
The precision physics needs at TeV-scale linear electron-positron colliders (ILC and CLIC) require a vertex-detector system with excellent flavour-tagging capabilities through a meas- urement of displaced vertices. This is essential, for example, for an explicit measurement of the Higgs decays to pairs of b-quarks, c-quarks and gluons. Efficient identification of top quarks in the decay t → W b will give access to the ttH-coupling measurement. In addition to those requirements driven by physics arguments, the CLIC bunch structure calls for hit tim- ing at the few-ns level. As a result, the CLIC vertex-detector system needs to have excellent spatial resolution, full geometrical coverage extending to low polar angles, extremely low material budget, low occupancy facilitated by time-tagging, and sufficient heat removal from sensors and readout. These considerations challenge current technological limits. A detector concept based on hybrid pixel-detector technology is under development for the CLIC ver- tex det...
Performance of the LHCb Vertex Locator
Latham, T
2012-01-01
LHCb is a dedicated flavour physics experiment at the Large Hadron Collider (LHC) at CERN. The Vertex Locator (VELO) is an essential part of the LHCb detector, permitting precision measurements of the production and decay vertices of beauty and charm particles. The VELO consists of a series of silicon micro-strip detectors, arranged in two retractable halves. Positioned only 7 mm from the beam during normal operations, it must withstand very high levels of radiation. The performance of the LHCb VELO during the first year of LHC physics running is presented.
The Zeus Copper/Uranium Critical Experiment at NCERC
Sanchez, Rene G. [Los Alamos National Laboratory; Hayes, David K. [Los Alamos National Laboratory; Bounds, John Alan [Los Alamos National Laboratory; Jackman, Kevin R. [Los Alamos National Laboratory; Goda, Joetta M. [Los Alamos National Laboratory
2012-06-15
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.
Searches for New Physics Using H1 and ZEUS Data
,
2010-01-01
Recent searches for new physics in ep collisions performed by the H1 and ZEUS collaborations are presented. Limits on different contact interaction models, large extra dimensions, R-parity violating SUSY, excited fermions and anomalous flavour-changing top couplings are shown. In addition, searches for new physics in exclusive final states such as events with isolated leptons and large missing transverse momentum or multi-lepton final states are presented.
Analog readout modules for the ZEUS microvertex detector
Fusayasu, T
1999-01-01
Analog readout modules have been developed for a silicon microvertex detector of the electron-proton collision experiment ZEUS. Analog signals kept in the front end are read out and digitized by ADCs and processed afterwards to reduce the data volume while keeping the signal information. We have developed prototype modules with 10-bit 10 MHz ADCs and digital processors built in Field Programmable Gate Arrays. Their performance was investigated.
First Results from the LHCb Vertex Locator
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...
The STAR Vertex Position Detector
Llope, W J; Nussbaum, T; Hoffmann, G W; Asselta, K; Brandenburg, J D; Butterworth, J; Camarda, T; Christie, W; Crawford, H J; Dong, X; Engelage, J; Eppley, G; Geurts, F; Hammond, J; Judd, E; McDonald, D L; Perkins, C; Ruan, L; Scheblein, J; Schambach, J J; Soja, R; Xin, K; Yang, C
2014-01-01
The 2x3 channel pseudo Vertex Position Detector (pVPD) in the STAR experiment at RHIC has been upgraded to a 2x19 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.
Some finite properties for vertex operator superalgebras
Dong, Chongying; Han, Jianzhi
2011-01-01
Vertex operator superalgebras are studied and various results on rational Vertex operator superalgebras are obtained. In particular, the vertex operator super subalgebras generated by the weight 1/2 and weight 1 subspaces are determined. It is also established that if the even part $V_{\\bar 0}$ of a vertex operator superalgebra $V$ is rational, so is $V.$
c, Aleksandar Ili\\'
2011-01-01
The vertex PI index is a distance--based molecular structure descriptor, that recently found numerous chemical applications. In order to increase diversity of this topological index for bipartite graphs, we introduce weighted version defined as $PI_w (G) = \\sum_{e = uv \\in E} (deg (u) + deg (v)) (n_u (e) + n_v (e))$, where $deg (u)$ denotes the vertex degree of $u$ and $n_u (e)$ denotes the number of vertices of $G$ whose distance to the vertex $u$ is smaller than the distance to the vertex $v$. We establish basic properties of $PI_w (G)$, and prove various lower and upper bounds. In particular, the path $P_n$ has minimal, while the complete tripartite graph $K_{n/3, n/3, n/3}$ has maximal weighed vertex $PI$ index among graphs with $n$ vertices. We also compute exact expressions for the weighted vertex PI index of the Cartesian product of graphs. Finally we present modifications of two inequalities and open new perspectives for the future research.
Belle II Silicon Vertex Detector
Mohanty, Gagan B
2015-01-01
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 a vertex detector, which comprises two layers of pixelated silicon detector and four layers of silicon vertex detector. We describe herein the design, prototyping and construction efforts of the Belle-II silicon vertex detector that is aimed to be commissioned towards the middle of 2017.
Energy-loss measurement with the ZEUS Central Tracking Detector
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.)
The LHCb Vertex Locator – Performance and Radiation Damage
Oblakowska-Mucha, A
2014-01-01
LHCb is a dedicated flavour physics experiment at the Large Hadron Collider at CERN. The Vertex Locator (VELO) is an important part of a LHCb tracking system, enabling precision measurement of beauty and charm mesons’ flight distance. The VELO consist of a set of silicon micro-strip detectors, arranged in two retractable halves, operating only 7 mm from the interac- tion region. In these proceedings the VELO performance during the Run 1 is summarised and radiation damage studies are presented.
Measurement of beauty production in DIS and extraction at ZEUS
Abramowicz, H.; Ingbir, R.; Kananov, S.; Levy, A.; Stern, A. [Tel Aviv University, Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics, Tel Aviv (Israel); Abt, I.; Caldwell, A.; Kollar, D.; Reisert, B.; Schmidke, W.B. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Adamczyk, L.; Bold, T.; Gach, G.; Grabowska-Bold, I.; Kisielewska, D.; Przybycien, M.; Suszycki, L. [AGH-University of Science and Technology, Faculty of Physics and Applied Computer Science, Cracow (Poland); Adamus, M.; Plucinski, P.; Tymieniecka, T. [Institute for Nuclear Studies, Warsaw (Poland); Aggarwal, R.; Kaur, M.; Kaur, P.; Singh, I. [Panjab University, Department of Physics, Chandigarh (India); Antonelli, S.; Basile, M.; Bindi, M.; Cifarelli, L.; Contin, A.; De Pasquale, S.; Sartorelli, G.; Zichichi, A. [University Bologna (Italy); INFN Bologna, Bologna (Italy); Antonioli, P.; Bari, G.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Cindolo, F.; Corradi, M.; Iacobucci, G.; Margotti, A.; Nania, R.; Polini, A. [INFN Bologna, Bologna (Italy); Antonov, A.; Dolgoshein, B.A.; Gladkov, D.; Sosnovtsev, V.; Stifutkin, A.; Suchkov, S. [Moscow Engineering Physics Institute, Moscow (Russian Federation); Arneodo, M.; Ruspa, M. [Universita del Piemonte Orientale, Novara (Italy); INFN, Torino (Italy); Aushev, V.; Aushev, Y.; Borodin, M.; Gogota, O.; Kadenko, I.; Korol, I.; Kuprash, O.; Lontkovskyi, D.; Makarenko, I.; Onishchuk, Yu.; Salii, A.; Tomalak, O.; Viazlo, V.; Volynets, O.; Zenaiev, O.; Zhmak, N.; Zolko, M. [National Academy of Sciences, and Kiev National University, Institute for Nuclear Research, Kiev (Ukraine); Bachynska, O.; Behnke, O.; Behr, J.; Behrens, U.; Blohm, C.; Borras, K.; Bot, D.; Ciesielski, R.; Coppola, N.; Fang, S.; Geiser, A.; Goettlicher, P.; Grebenyuk, J.; Gregor, I.; Haas, T.; Hain, W.; Huettmann, A.; Januschek, F.; Kahle, B.; Katkov, I.I.; Klein, U.; Koetz, U.; Kowalski, H.; Libov, V.; Lisovyi, M.; Lobodzinska, E. [and others
2010-10-15
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
Adler, V.
2002-09-01
During the shut-down of the electron-proton collider HERA at DESY in Hamburg in the years 2000/2001, the new silicon strip vertex detector MVD has been installed into the ZEUS experiment to achieve a higher quality in the reconstruction of particle tracks. Before its installation, the MVD and all associated hard- and software components have been tested. The objectives of this test - the so-called ''system test'' - were to investigate the performance of the detector and to check the stability and interplay of all components and the monitoring systems. In this thesis, the online software to calibrate the detector signals and to store and monitor the calibration parameters has been developed. Furthermore the stability of the calibration parameters over the system test running period has been investigated. In addition, the simulation of the analog detector signals (digitisation) has been worked out, and the simulated signals have been compared with the real detector response. After a short introduction into the HERA collider and the ZEUS experiment in Chap. 1, the principles of silicon strip detectors are exposed in Chap. 2. Chap. 3 describes the layout of the MVD in detail, and an overview of the data acquisition system is given. Some results of previous measurements on single silicon strip detectors of the MVD obtained with an electron test beam, which are relevant for this thesis, are summarised. The aims and the set-up of the system test are described in Chap. 4. Then results of analyses on the system test data are presented, which have been obtained in parallel to the work of this thesis. The calibration of the detector signals is described in detail in Chap. 5. After an introduction into the meaning and the calculation of the calibration parameters, the methods to obtain, monitor and store them are explained. Also an analysis is introduced, which studies the stability of the calibration parameters. Overall 98% of all MVD channels operate
A Novel Vertex Affinity for Community Detection
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.
Belle II silicon vertex detector
Adamczyk, K.; Aihara, H.; Angelini, C.; Aziz, T.; Babu, V.; Bacher, S.; Bahinipati, S.; Barberio, E.; Baroncelli, Ti.; Baroncelli, To.; Basith, A. K.; Batignani, G.; Bauer, A.; Behera, P. K.; Bergauer, T.; Bettarini, S.; Bhuyan, B.; Bilka, T.; Bosi, F.; Bosisio, L.; Bozek, A.; Buchsteiner, F.; Casarosa, G.; Ceccanti, M.; Červenkov, D.; Chendvankar, S. R.; Dash, N.; Divekar, S. T.; Doležal, Z.; Dutta, D.; Enami, K.; Forti, F.; Friedl, M.; Hara, K.; Higuchi, T.; Horiguchi, T.; Irmler, C.; Ishikawa, A.; Jeon, H. B.; Joo, C. W.; Kandra, J.; Kang, K. H.; Kato, E.; Kawasaki, T.; Kodyš, P.; Kohriki, T.; Koike, S.; Kolwalkar, M. M.; Kvasnička, P.; Lanceri, L.; Lettenbicher, J.; Maki, M.; Mammini, P.; Mayekar, S. N.; Mohanty, G. B.; Mohanty, S.; Morii, T.; Nakamura, K. R.; Natkaniec, Z.; Negishi, K.; Nisar, N. K.; Onuki, Y.; Ostrowicz, W.; Paladino, A.; Paoloni, E.; Park, H.; Pilo, F.; Profeti, A.; Rashevskaya, I.; Rao, K. K.; Rizzo, G.; Rozanska, M.; Sandilya, S.; Sasaki, J.; Sato, N.; Schultschik, S.; Schwanda, C.; Seino, Y.; Shimizu, N.; Stypula, J.; Suzuki, J.; Tanaka, S.; Tanida, K.; Taylor, G. N.; Thalmeier, R.; Thomas, R.; Tsuboyama, T.; Uozumi, S.; Urquijo, P.; Vitale, L.; Volpi, M.; Watanuki, S.; Watson, I. J.; Webb, J.; Wiechczynski, J.; Williams, S.; Würkner, B.; Yamamoto, H.; Yin, H.; Yoshinobu, T.
2016-09-01
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.
Belle II silicon vertex detector
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.
[CII] At 1 Star Formation in the Early Universe with Zeus (1 and 2)
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.
The silicon vertex locator for the LHCb upgrade
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.
Spinfoam Cosmology with the Proper Vertex
Vilensky, Ilya
2017-01-01
A modification of the EPRL vertex amplitude in the spin-foam framework of quantum gravity - so-called ``proper vertex amplitude'' - has been developed to enable correct semi-classical behavior to conform to the classical Regge calculus. The proper vertex amplitude is defined by projecting to the single gravitational sector. The amplitude is recast into an exponentiated form and we derive the asymptotic form of the projector part of the action. This enables us to study the asymptotics of the proper vertex by applying extended stationary phase methods. We use the proper vertex amplitude to investigate transition amplitudes between coherent quantum boundary states of cosmological geometries. In particular, Hartle-Hawking no-boundary states are computed in the proper vertex framework. We confirm that in the classical limit the Hartle-Hawking wavefunction satisfies the Hamiltonian constraint. Partly supported by NSF grants PHY-1205968 and PHY-1505490.
Dijets in diffractive photoproduction measured with the ZEUS experiment
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 0.2
Neutral strangeness production with the ZEUS detector at HERA
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.)
AUTHOR|(SzGeCERN)734627
2015-01-01
A vertex-detector concept is under development for the proposed multi-TeV linear e+e- Compact Linear Collider (CLIC). To perform precision physics measurements in a chal- lenging environment, the CLIC vertex detector pushes the technological requirements to the limits. This paper reviews the requirements for the CLIC vertex detector and gives an over- view of recent R&D achievements in the domains of sensor, readout, powering and cooling.
Alipour Tehrani, Niloufar
2016-07-01
A vertex detector concept is under development for the proposed multi-TeV linear e+e- Compact Linear Collider (CLIC). To perform precision physics measurements in a challenging environment, the CLIC vertex detector pushes the technological requirements to the limits. This paper reviews the requirements for the CLIC vertex detector and gives an overview of recent R&D achievements in the domains of sensor, readout, powering and cooling.
The SUPERB silicon vertex tracker
Forti, F., E-mail: Francesco.Forti@pi.infn.it [INFN-Pisa and Universita di Pisa (Italy); Avanzini, C.; Batignani, G.; Bettarini, S.; Bosi, F.; Calderini, G.; Ceccanti, M.; Cenci, R.; Cervelli, A.; Crescioli, F.; Dell' Orso, M.; Giannetti, P.; Giorgi, M.A. [INFN-Pisa and Universita di Pisa (Italy); Lusiani, A. [Scuola Normale Superiore and INFN-Pisa (Italy); Gregucci, S.; Mammini, P.; Marchiori, G.; Massa, M.; Morsani, F.; Neri, N. [INFN-Pisa and Universita di Pisa (Italy)
2011-04-21
The SUPERB asymmetric e{sup +}e{sup -} collider, to be built near the INFN National Frascati Laboratory in Italy, has been designed to deliver a luminosity greater than 10{sup 36} cm{sup -2} s{sup -1} with moderate beam currents, allowing precision measurements in the flavour sector sensitive to New Physics. The conceptual design of the Silicon Vertex Tracker for the SUPERB Detector is presented, based on double-sided silicon strip detectors for the outer layers, with the addition of an innermost Layer 0 close to the interaction point, with low material budget and capable of sustaining a background rate of several MHz/cm{sup 2}.
The CDF Silicon Vertex Detector
Tkaczyk, S.; Carter, H.; Flaugher, B. [and others
1993-09-01
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 detector in the radiation environment are discussed. The device has been taking colliding beams data since May of 1992, performing at its best design specifications and enhancing the physics program of CDF.
A new construction for vertex decomposable graphs
Nasser Hajisharifi
2016-09-01
Full Text Available Let G be a finite simple graph on the vertex set V(G and let S⊆V(G. Adding a whisker to G at x means adding a new vertex y and edge xy to G where x∈V(G. The graph G∪W(S is obtained from G by adding a whisker to every vertex of S. We prove that if G∖S is either a graph with no chordless cycle of length other than 3 or 5, chordal graph or C5, then G∪W(S is a vertex decomposable graph.
Quantum toroidal algebras and their vertex representations
Saitô, Y
1996-01-01
We construct the vertex representations of the quantum toroidal algebras $U_q({\\frak {sl}}_{n+1,tor})$. In the classical case the vertex representations are not irreducible. However in the quantum case they are irreducible. For n=1, we construct a set of finitely many generators of $U_q({\\frak {sl}}_{2,tor})$.
New vertex reconstruction algorithms for CMS
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
Vertex Reconstruction in ATLAS Run II
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.
A ZEUS next-to-leading-order QCD analysis of data on deep inelastic scattering
Chekanov, S; Adamczyk, L; Adamus, M; Adler, V; Aghuzumtsyan, G; Allfrey, P D; Antonioli, P; Antonov, A; Arneodo, M; Bailey, D S; Bamberger, A; Barakbaev, A N; Barbagli, G; Barbi, M; Bari, G; Barreiro, F; Bartsch, D; Basile, M; Behrens, U; Bell, M A; Bellagamba, L; Bellan, P M; Benen, A; Bertolin, A; Bhadra, S; Bloch, I; Bold, T; Boos, E G; Borras, K; Boscherini, D; Brock, I; Brook, N H; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Bussey, P J; Butterworth, J M; Büttner, C; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carli, T; Carlin, R; Cassel, D G; Catterall, C D; Chwastowski, J; Abramowicz, H; Ciborowski, J; Ciesielski, R; Cifarelli, Luisa; Cindolo, F; Cole, J E; Collins-Tooth, C; Contin, A; Cooper-Sarkar, A M; Coppola, N; Corradi, M; Corriveau, F; Costa, M; Cottrell, A; Cui, Y; D'Agostini, G; Dal Corso, F; Danilov, P; De Pasquale, S; Dementiev, R K; Derrick, M; Devenish, R C E; Dhawan, S; Dobur, D; Dolgoshein, B A; Doyle, A T; Drews, G; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, Andrzej; Everett, A; Ferrando, J; Ferrero, M I; Figiel, J; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fry, C; Gabareen, A; Galas, A; Gallo, E; Garfagnini, A; Geiser, A; Genta, C; Gialas, I; Giusti, P; Gladilin, L K; Gladkov, D; Glasman, C; Göbel, F; Goers, S; Goncalo, R; González, O; Gosau, T; Göttlicher, P; Grabowska-Bold, I; Graciani-Díaz, R; Grigorescu, G; Grijpink, S; Groys, M; Grzelak, G; Gutsche, O; Gwenlan, C; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hamilton, J; Hanlon, S; Hart, C; Hartmann, H; Hartner, G; Heaphy, E A; Heath, G P; Helbich, M; Hilger, E; Hochman, D; Holm, U; Horn, C; Iacobucci, G; Iga, Y; Irrgang, P; Jakob, H P; Jiménez, M; Jones, T W; Kagawa, S; Kahle, B; Kaji, H; Kananov, S; Karshon, U; Karstens, F; Kasemann, M; Kataoka, M; Katkov, I I; Kcira, D; Keramidas, A; Khein, L A; Kim, J Y; Kind, O; Kisielewska, D; Kitamura, S; Koffeman, E; Kohno, T; Kooijman, P; Koop, T; Korzhavina, I A; Kotanski, A; Kötz, U; Kowal, A M; Kowalski, H; Kramberger, G; Kreisel, A; Krumnack, N; Kulinski, P; Kuze, M; Kuzmin, V A; Labarga, L; Lammers, S; Lelas, D; Levchenko, B B; Levy, A; Li, L; Lightwood, M S; Lim, H; Limentani, S; Ling, T Y; Liu, C; Liu, X; Löhr, B; Lohrmann, E; Loizides, J H; Long, K R; Longhin, A; Lukasik, J; Lukina, O Yu; Luzniak, P; Ma, K J; Maddox, E; Magill, S; Malka, J; Mankel, R; Margotti, A; Marini, G; Martin, J F; Martínez, M; Mastroberardino, A; Matsuzawa, K; Mattingly, M C K; Melzer-Pellmann, I A; Menary, S R; Metlica, F; Meyer, U; Miglioranzi, S; Milite, M; Mirea, A; Monaco, V; Montanari, A; Musgrave, B; Nagano, K; Namsoo, T; Nania, R; Nguyen, C N; Nigro, A; Ning, Y; Noor, U; Notz, D; Nowak, R J; Nuncio-Quiroz, A E; Oh, B Y; Olkiewicz, K; Ota, O; Padhi, S; Palmonari, F; Patel, S; Paul, E; Pavel, Usan; Pawlak, J M; Pelfer, P G; Pellegrino, A; Pesci, A; Piotrzkowski, K; Plamondon, M; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Proskuryakov, A S; Przybycien, M B; Rautenberg, J; Raval, A; Reeder, D D; Ren, Z; Renner, R; Repond, J; Ri, Y D; Rinaldi, L; Robins, S; Rosin, M; Ruspa, M; Ryan, P; Sacchi, R; Salehi, H; Santamarta, R; Sartorelli, G; Savin, A A; Saxon, D H; Schagen, S; Schioppa, M; Schlenstedt, S; Schleper, P; Schmidke, W B; Schneekloth, U; Schörner-Sadenius, T; Sciulli, F; Shcheglova, L M; Skillicorn, I O; Slominski, W; Smith, W H; Soares, M; Solano, A; Son, D; Sosnovtsev, V V; Stairs, D G; Stanco, L; Standage, J; Stifutkin, A; Stonjek, S; Stopa, P; Stösslein, U; Straub, P B; Suchkov, S; Susinno, G; Suszycki, L; Sutiak, J; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tapper, A D; Targett-Adams, C; Tassi, E; Tawara, T; Terron, J; Tiecke, H G; Tokushuku, K; Tsurugai, T; Turcato, M; Tymieniecka, T; Tyszkiewicz, A; Ukleja, A; Ukleja, J; Vázquez, M; Vlasov, N N; Voss, K C; Walczak, R; Walsh, R; Wang, M; Whitmore, J J; Whyte, J; Wichmann, K; Wick, K; Wiggers, L; Wills, H H; Wing, M; Wlasenko, M; Wolf, G; Yagues-Molina, A G; Yamada, S; Yamazaki, Y; Yoshida, R; Youngman, C; Zambrana, M; Zawiejski, L; Zeuner, W; Zhautykov, B O; Zhou, C; Zichichi, A; Ziegler, A; Zotkin, D S; Zotkin, S A; De Favereau, J; De Wolf, E; Del Peso, J
2003-01-01
Next-to-leading order QCD analyses of the ZEUS data on deep inelastic scattering together with fixed-target data have been perfomed, from which the gluon and the quark densities of the proton and the value of the strong coupling constant, alpha_s(M_Z), were extracted. The study includes a full treatment of the experimental systematic uncertainties including point-to-point correlations. The resulting uncertainties in the parton density functions are presented. A combined fit for alpha_s(M_Z) and the gluon and qurak densities yields a value of alpha_s(M_Z) in agreement with the world average. The parton density functions derived from ZEUS data alone indicate the importance of HERA data in determining sea quark and gluon distributions at low x. The limits of applicability of the theoretical formalism have been explored by comparing the fit predictions to ZEUS data at very low Q^2.
Diffractive dijet production in deep inelastic scattering at ZEUS
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.)
Recursively arbitrarily vertex-decomposable suns
Olivier Baudon
2011-01-01
Full Text Available A graph \\(G = (V,E\\ is arbitrarily vertex decomposable if for any sequence \\(\\tau\\ of positive integers adding up to \\(|V|\\, there is a sequence of vertex-disjoint subsets of \\(V\\ whose orders are given by \\(\\tau\\, and which induce connected graphs. The aim of this paper is to study the recursive version of this problem on a special class of graphs called suns. This paper is a complement of [O. Baudon, F. Gilbert, M. Woźniak, Recursively arbitrarily vertex-decomposable graphs, research report, 2010].
DEPFET Vertex Detectors: Status and Plans
Simon, Frank
2010-01-01
DEPFET active pixel sensors are a well-developed technology for vertex detectors at future colliders. Extensive test beam campaigns have proven the excellent performance of these devices, and their radiation hardness has been thoroughly tested. For the Belle-II experiment at the SuperKEKB collider, a new vertex detector based on DEPFET technology is being developed, using sensors thinned down to 75 \\mu m. We give an overview over recent results with test devices using ILC pixel geometries as well as the concepts and challenges for the Belle-II pixel vertex tracker and discuss how the R&D for the ILC VXD can take advantage of these developments.
Vertex finding with deformable templates at LHC
Stepanov, N. [European Organization for Nuclear Research, Geneva (Switzerland); Khanov, A. [European Organization for Nuclear Research, Geneva (Switzerland)
1997-04-11
We present a novel vertex finding technique. The task is formulated as a discrete-continuous optimisation problem in a way similar to the deformable templates approach for the track finding. Unlike the track finding problem, ``elastic hedgehogs`` rather than elastic arms are used as deformable templates. They are initialised by a set of procedures which provide zero level approximation for vertex positions and track parameters at the vertex point. The algorithm was evaluated using the simulated events for the LHC CMS detector and demonstrated good performance. (orig.).
Spinfoam cosmology with the proper vertex amplitude
Vilensky, Ilya
2016-01-01
The proper vertex amplitude is derived from the EPRL vertex by restricting to a single gravitational sector in order to achieve the correct semi-classical behaviour. We apply the proper vertex to calculate a cosmological transition amplitude that can be viewed as the Hartle-Hawking wavefunction. To perform this calculation we deduce the integral form of the proper vertex and use extended stationary phase methods to estimate the large-volume limit. We show that the resulting amplitude satisfies an operator constraint whose classical analogue is the Hamiltonian constraint of the Friedmann-Robertson-Walker cosmology. We find that the constraint dynamically selects the relevant family of coherent states and demonstrate a similar dynamic selection in standard quantum mechanics.
Vertex-antimagic Labelings of Regular Graphs
Ali AHMAD; Kashif ALI; Martin BA(C)A; Petr KOV(A)(R); Andrea SEMANI(C)OV(A)-FE(N)OV(C)(I)KOV(A)
2012-01-01
Let G =(V,E) be a finite,simple and undirected graph with p vertices and q edges.An (a,d)-vertex-antimagic total labeling of G is a bijection f from V(G).∪E(G) onto the set of consecutive integers 1,2,...,p + q,such that the vertex-weights form an arithmetic progression with the initial term a and difference d,where the vertex-weight of x is the sum of the value f(x) assigned to the vertex x together with all values f(xy) assigned to edges xy incident to x.Such labeling is called super if the smallest possible labels appear on the vertices.In this paper,we study the properties of such labelings and examine their existence for 2r-regular graphs when the difference d is 0,1,...,r + 1.
The Perfect Quark-Gluon Vertex Function
Orginos, K; Brower, Richard C; Chandrasekharan, S; Wiese, U J
1998-01-01
We evaluate a perfect quark-gluon vertex function for QCD in coordinate space and truncate it to a short range. We present preliminary results for the charmonium spectrum using this quasi-perfect action.
Vertex occlusal radiography in localizing unerupted mesiodentes
P Chalakkal
2011-01-01
Full Text Available The aim was to compare the vertex occlusal projection with the anterior maxillary occlusal projection in localizing the position of mesiodentes. Mesiodentes were observed in an 8-year-old boy with an anterior maxillary occlusal radiograph. A vertex occlusal radiograph was taken to compare it with the former in terms of mesiodentes localization with respect to the maxillary central incisors. The vertex occlusal radiograph provided greater details of the position and proximity of mesiodentes with respect to the long axis of maxillary central incisors in comparison to the anterior maxillary occlusal radiograph. Vertex occlusal radiography is an important diagnostic tool in diagnosing the presence, position, and proximity of mesiodentes with respect to the long axis of normally aligned maxillary central incisors. However, it is not recommended for routine use in a patient as its radiation dose is higher than conventional intraoral radiographic methods.
A Response to Zeus Leonardo's "Critical Empiricism: Reading Data with Social Theory"
Apple, Michael W.
2010-01-01
In this article the author briefly brings up two related conceptual and political areas that Zeus Leonardo and the author might want to discuss further. These concern the status of the language of "resistance" and "agency," terms that play a large part in Leonardo's essay and that are now among the pantheon of accepted political and analytic…
Introducing ZEUS-MP A 3D, Parallel, Multiphysics Code for Astrophysical Fluid Dynamics
Norman, M L
2000-01-01
We describe ZEUS-MP: a Multi-Physics, Massively-Parallel, Message-Passing code for astrophysical fluid dynamics simulations in 3 dimensions. ZEUS-MP is a follow-on to the sequential ZEUS-2D and ZEUS-3D codes developed and disseminated by the Laboratory for Computational Astrophysics (lca.ncsa.uiuc.edu) at NCSA. V1.0 released 1/1/2000 includes the following physics modules: ideal hydrodynamics, ideal MHD, and self-gravity. Future releases will include flux-limited radiation diffusion, thermal heat conduction, two-temperature plasma, and heating and cooling functions. The covariant equations are cast on a moving Eulerian grid with Cartesian, cylindrical, and spherical polar coordinates currently supported. Parallelization is done by domain decomposition and implemented in F77 and MPI. The code is portable across a wide range of platforms from networks of workstations to massively parallel processors. Some parallel performance results are presented as well as an application to turbulent star formation.
Measurement of D-+/- production in deep inelastic ep scattering with the ZEUS detector at HERA
Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwa, R.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Aushev, V.; Aushev, Y.; Bachynska, O.; Bamberger, A.; Barakbaev, A. N.; Barbagli, G.; Bari, G.; Barreiro, F.; Bartosik, N.; Bartsch, D.; Basile, M.; Behnke, O.; Behr, J.; Behrens, O.; Bellagamba, L.; Bertoin, A.; Bhadra, S.; Bindi, M.; Blohm, C.; Bokhonov, V.; Bold, T.; Boos, E. G.; Borras, K.; Boscherini, D.; Brock, I.; Brownson, E.; Brugnera, R.; Bruemmer, N.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bussey, P. J.; Bylsma, B.; Caldwell, A.; Capua, M.; Carlin, R.; Catterall, C. D.; Chekanov, S.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Cooper-Sarkar, A. M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; D'Agostini, G.; Dal Corso, F.; del Peso, J.; Dementiev, R. K.; De Pasquale, S.; Derrick, M.; Devenish, R. C. E.; Dobur, D.; Dolgoshein, B. A.; Dolinska, G.; Doyle, A. T.; Drugakov, V.; Durkin, L. S.; Dusini, S.; Eisenberg, Y.; Ermolov, P. F.; Eskreys, A.; Fazio, S.; Ferrando, J.; Ferrero, M. I.; Figiel, J.; Foster, B.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gialas, I.; Gizhko, A.; Gladilin, L. K.; Gladkov, D.; Glasman, C.; Gogota, O.; Goubkov, Yu A.; Goettlicher, P.; Grabowska-Bold, I.; Grebenyuk, J.; Gregor, I.; Grigorescu, G.; Grzelak, G.; Gueta, O.; Guzik, M.; Gwenlan, C.; Haas, T.; Hain, W.; Hamatsu, R.; Hart, . J. C.; Hartmann, H.; Hartner, G.; Hilger, E.; Hochman, D.; Hori, R.; Huettmann, A.; Ibrahim, Z. A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Iudin, A.; Jakob, H-P.; Januschek, F.; Jones, T. W.; Juengst, M.; Kadenko, I.; Kahle, B.; Kananov, S.; Kanno, T.; Karshon, U.; Karstens, F.; Katkov, I. I.; Kaur, M.; Kaur, P.; Keramidas, A.; Khein, L. A.; Kim, J. Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Kein, U.; Kondrashova, N.; Kononenko, O.; Kooijman, P.; Korol, Ie.; Korzhavina, I. A.; Kotanski, A.; Koets, U.; Kovalchuk, N.; Kowalski, H.; Kuprash, O.; Kuze, M.; Lee, A.; Levehenko, B. B.; Libov, V.; Limentani, S.; Ling, T. Y.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Loehr, B.; Lohrmann, E.; Long, K. R.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; Maeda, J.; Magill, S.; Makarenko, I.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Mastroberardino, A.; Mattingly, M. C. K.; Melzer-Pellmann, I-A.; Mergeltneyer, S.; Miglioranzi, S.; Idris, F. Mohamad; Monaco, V.; Montanari, A.; Mujkic, K.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Nigro, A.; Ning, Y.; Nobe, I.; Notz, D.; Nowak, R. J.; Nuncio-Quiroz, A. E.; Oh, B. Y.; Okazaki, N.; Olkiewicz, K.; Onishchuk, Yu; Papageorgiu, K.; Parenti, A.; Pawlak, J. M.; Pawlik, B.; Pelfer, P. G.; Pellegrino, A.; Perlanski, W.; Perrey, H.; Piotrzkowski, K.; Plucinski, P.; Pokrovskiy, N. S.; Polini, A.; Proskuryakov, A. S.; Przybycien, M.; Raval, A.; Reeder, D. D.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y. D.; Robertson, R.; Roloff, P.; Rubinsky, I.; Ruspa, M.; Sacchi, R.; Samson, U.; Sartorelli, G.; Savin, A. A.; Saxon, D. H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W. B.; Schneekloth, U.; Schoenberg, V.; Schoerner-Sadenius, T.; Schwartz, J.; Sciulli, F.; Shcheglova, L. M.; Shehzadi, R.; Singh, I.; Skillicorn, I. O.; Slominski, W.; Smith, W. H.; Sola, V.; Solano, A.; Son, D.; Sosnovtsev, V.; Spiridonov, A.; Stadie, H.; Stanco, L.; Stefaniuk, N.; Stern, A.; Stewart, T. P.; Stifutkin, A.; Stopa, P.; Suchkov, S.; Susinno, G.; Suszycki, L.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tapper, A. D.; Tassi, E.; Terron, J.; Theedt, T.; Tiecke, H.; Tokushuku, K.; Tomaszewska, J.; Trofymov, A.; Trusov, V.; Tsurugai, T.; Turcato, M.; Turkot, O.; Tymieniecka, T.; Vazquez, M.; Verbytskyi, A.; Viazlo, O.; Vlasov, N. N.; Walczak, R.; Abdullah, W. A. T. Wan; Whitmore, J. J.; Wichmann, K.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Yaguees-Molina, A. G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Zakharchuk, N.; Zarnecki, A. B.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhautykov, B. O.; Zhmak, N.; Zichichi, A.; Zolkapli, Z.; Zotkin, D. S.
2013-01-01
Charm production in deep inelastic e p scattering was measured with the ZEUS detector using an integrated luminosity of 354 pb(-1). Charm quarks were identified by reconstructing D-+/- mesons in the D-+/- -> K--/+pi(+/-)pi(+/-) decay channel. Lifetime information was used to reduce combinatorial bac
Introducing zeus-mp: a 3d, parallel, multiphysics code for astrophysical fluid dynamics
Michael L. Norman
2000-01-01
Full Text Available Describimos ZEUS-MP: un c odigo Multi-F sica, Masivamente-Paralelo, Pasa-Mensajes para simulaciones tridimensionales de din amica de uidos astrof sicos. ZEUS-MP es la continuaci on de los c odigos ZEUS-2D y ZEUS-3D, desarrollados y diseminados por el Laboratorio de Astrof sica Computacional (lca.ncsa.uiuc.edu del NCSA. La versi on V1.0, liberada el 1/1/2000, contiene los siguientes m odulos: hidrodin amica ideal, MHD ideal y auto-gravedad. Las pr oximas versiones tendr an difusi on radiativa de ujo limitado, conducci on de calor, plasma de dos temperaturas y funciones de enfriamiento y calentamiento. Las ecuaciones covariantes est an avanzadas en una malla Euleriana m ovil en coordenadas Cartesianas, cil ndricas y polares esf ericas. La paralelizaci on es hecha por descomposici on del dominio y est a implementada en F77 y MPI. El c odigo es portable en un amplio rango de plataformas, desde redes de estaciones de trabajo hasta procesadores de paralelismo masivo. Se presentan algunos resultados de la e ciencia en paralelo junto con una aplicaci on a formaci on estelar turbulenta.
Recursively arbitrarily vertex-decomposable graphs
Olivier Baudon
2012-01-01
Full Text Available A graph \\(G = (V;E\\ is arbitrarily vertex decomposable if for any sequence \\(\\tau\\ of positive integers adding up to \\(|V|\\, there is a sequence of vertex-disjoint subsets of \\(V\\ whose orders are given by \\(\\tau\\, and which induce connected graphs. The main aim of this paper is to study the recursive version of this problem. We present a solution for trees, suns, and partially for a class of 2-connected graphs called balloons.
Vertex stability and topological transitions in vertex models of foams and epithelia
Spencer, Meryl A; Lubensky, David K
2016-01-01
In computer simulations of dry foams and of epithelial tissues, vertex models are often used to describe the shape and motion of individual cells. Although these models have been widely adopted, relatively little is known about their basic theoretical properties. For example, while fourfold vertices in real foams are always unstable, it remains unclear whether a simplified vertex model description has the same behavior. Here, we study vertex stability and the dynamics of T1 topological transitions in vertex models. We show that, when all edges have the same tension, stationary fourfold vertices in these models do indeed always break up. In contrast, when tensions are allowed to depend on edge orientation, fourfold vertices can become stable, as is observed in some biological systems. More generally, our formulation of vertex stability leads to an improved treatment of T1 transitions in simulations and paves the way for studies of more biologically realistic models that couple topological transitions to the dy...
Trace Identities for the Topological Vertex
Bryan, Jim; Young, Benjamin
2016-01-01
The topological vertex is a universal series which can be regarded as an object in combinatorics, representation theory, geometry, or physics. It encodes the combinatorics of 3D partitions, the action of vertex operators on Fock space, the Donaldson-Thomas theory of toric Calabi-Yau threefolds, or the open string partition function of $\\mathbb{C}^3$. We prove several identities in which a sum over terms involving the topological vertex is expressed as a closed formula, often a product of simple terms, closely related to Fourier expansions of Jacobi forms. We use purely combinatorial and representation theoretic methods to prove our formulas, but we discuss applications to the Donaldson-Thomas invariants of elliptically fibered Calabi-Yau threefolds at the end of the paper.
Open string amplitudes of closed topological vertex
Takasaki, Kanehisa
2016-01-01
The closed topological vertex is the simplest "off-strip" case of non-compact toric Calabi-Yau threefolds with acyclic web diagrams. By the diagrammatic method of topological vertex, open string amplitudes of topological string theory therein can be obtained by gluing a single topological vertex to an "on-strip" subdiagram of the tree-like web diagram. If non-trivial partitions are assigned to just two parallel external lines of the web diagram, the amplitudes can be calculated with the aid of techniques borrowed from the melting crystal models. These amplitudes are thereby expressed as matrix elements, modified by simple prefactors, of an operator product on the Fock space of 2D charged free fermions. This fermionic expression can be used to derive $q$-difference equations for generating functions of special subsets of the amplitudes. These $q$-difference equations may be interpreted as the defining equation of a quantum mirror curve.
Vertex Operators and Moduli Spaces of Sheaves
Carlsson, Erik
2009-01-01
The Nekrasov partition function in supersymmetric quantum gauge theory is mathematically formulated as an equivariant integral over certain moduli spaces of sheaves on a complex surface. In ``Seiberg-Witten Theory and Random Partitions'', Nekrasov and Okounkov studied these integrals using the representation theory of ``vertex operators'' and the infinite wedge representation. Many of these operators arise naturally from correspondences on the moduli spaces, such as Nakajima's Heisenberg operators, and Grojnowski's vertex operators. In this paper, we build a new vertex operator out of the Chern class of a vector bundle on a pair of moduli spaces. This operator has the advantage that it connects to the partition function by definition. It also incorporates the canonical class of the surface, whereas many other studies assume that the class vanishes. When the moduli space is the Hilbert scheme, we present an explicit expression in the Nakajima operators, and the resulting combinatorial identities. We then apply...
Primary Vertex Reconstruction at the ATLAS Experiment
Grimm, Kathryn; The ATLAS collaboration
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.
The superB silicon vertex tracker
Rizzo, G., E-mail: giuliana.rizzo@pi.infn.i [INFN-Pisa and Universita di Pisa (Italy); Avanzini, C.; Batignani, G.; Bettarini, S.; Bosi, F.; Calderini, G.; Ceccanti, M.; Cenci, R.; Cervelli, A.; Crescioli, F.; Dell' Orso, M.; Forti, F.; Giannetti, P.; Giorgi, M.A. [INFN-Pisa and Universita di Pisa (Italy); Lusiani, A. [Scuola Normale Superiore and INFN-Pisa (Italy); Gregucci, S.; Mammini, P.; Marchiori, G.; Massa, M.; Morsani, F. [INFN-Pisa and Universita di Pisa (Italy)
2010-05-21
The SuperB asymmetric e{sup +}-e{sup -} collider has been designed to deliver a luminosity greater than 10{sup 36}cm{sup -2}s{sup -1} with moderate beam currents. Comparing to current B-Factories, the reduced center of mass boost of the SuperB machine requires improved vertex resolution to allow precision measurements sensitive to New Physics. We present the conceptual design of the silicon vertex tracker (SVT) for the SuperB detector with the present status of the R and D on the different options under study for its innermost Layer0.
Vertexing and Tracking Software at LHCb
Bowen, Espen Eie
2015-01-01
The LHCb experiment is a dedicated heavy flavour experiment at the LHC. Its primary goal is to search for indirect evidence of New Physics in CP violation and rare decays of beauty and charm hadrons. The detector includes a high granularity silicon-strip vertex detector, a silicon-strip detector upstream of the magnet and three stations of silicon-strip detectors and straw drift tubes downstream of the magnet. The software used to perform the track reconstruction and primary vertex reconstruction is described in detail along with a discussion of its performance.
On deformation theory of quantum vertex algebras
Grosse, H; Grosse, Harald; Schlesinger, Karl-Georg
2005-01-01
We study an algebraic deformation problem which captures the data of the general deformation problem for a quantum vertex algebra. We derive a system of coupled equations which is the counterpart of the Maurer-Cartan equation on the usual Hochschild complex of an assocative algebra. We show that this system of equations results from an action principle. This might be the starting point for a perturbative treatment of the deformation problem of quantum vertex algebras. Our action generalizes the action of the Kodaira-Spencer theory of gravity and might therefore also be of relevance for applications in string theory.
Vertex Reconstruction for AEGIS’ FACT Detector
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.
On spectral theory of quantum vertex operators
Etingof, P
1994-01-01
In this note we prove the Davies-Foda-Jimbo-Miwa-Nakayashiki conjecture on the asymptotics of the composition of n quantum vertex operators for the quantum affine algebra U_q(\\hat sl_2), as n goes to infinity. For this purpose we define and study the leading eigenvalue and eigenvector of the product of two components of the quantum vertex operator. This eigenvector and the corresponding eigenvalue were recently computed by M.Jimbo. The results of his computation are given in Section 4.
Vertex operators in solvable lattice models
Foda, O E; Miwa, T; Miki, K; Nakayashiki, A; Foda, Omar; Jimbo, Michio; Miwa, Tetsuji; Miki, Kei; Nakayashiki, Atsushi
1994-01-01
We formulate the basic properties of q-vertex operators in the context of the Andrews-Baxter-Forrester (ABF) series, as an example of face-interaction models, derive the q-difference equations satisfied by their correlation functions, and establish their connection with representation theory. We also discuss the q-difference equations of the Kashiwara-Miwa (KM) series, as an example of edge-interaction models. Next, the Ising model--the simplest special case of both ABF and KM series--is studied in more detail using the Jordan-Wigner fermions. In particular, all matrix elements of vertex operators are calculated.
Vertex Detector Performance for CLICdet, FCCee & FCChh.
Rasmussen, Peter Winkel
2017-01-01
The performance of the vertex detectors planned for CLICdet, FCCee & FCChh was tested in this project. This was done my studying the figure of merit for a vertex detector which is the transverse impact parameter resolution $\\sigma(d_0)$. This was carried out by simulating single $\\mu^-$ at different energies, polar angles, $\\theta$ with a uniform distribution in the azimuthal angle $\\phi$. The events were reconstructed and the distribution $\\Delta(d_0) = d_{0,reco}-d_{0,true}$ was fitted with a Gaussian function where the width of the function resulted in $\\sigma(d_0)$. The effect of material budget and fit function on this was also tested.
Measurement of the Luminosity in the ZEUS Experiment at HERA II
Adamczyk, L; Bold, T; Borzemski, P; Buettner, C; Caldwell, A; Chwastowski, J; Daniluk, W; Drugakov, V; Eskreys, A; Figiel, J; Galas, A; Gil, M; Helbich, M; Januscheck, F; Jurkiewicz, P; Kisielewska, D; Klein, U; Kotarba, A; Lohmann, W; Ning, Y; Oliwa, K; Olkiewicz, K; Paganis, S; Pieron, J; Przybycien, M; Ren, Z; Ruchlewicz, W; Schmidke, W; Schneekloth, U; Sciulli, F; Stopa, P; Sztuk-Dambietz, J; Suszycki, L; Sutiak, J; Wierba, W; Zawiejski, L
2013-01-01
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.
Measurement of neutral current cross-sections at high Bjorken- with the ZEUS detector at HERA
Inderpal Singh; on behalf of the ZEUS Collaboration
2012-11-01
A new method is employed to measure the neutral current cross-section up to Bjorken values of 1 with the ZEUS detector at HERA using an integrated luminosity of 187 pb-1 of electron–proton collisions and 142 pb-1 of positron–proton collisions, at a centre-of-mass energy of 318 GeV. Cross-sections have been extracted for 2 > 575 GeV2. A much improved precision with respect to the previous ZEUS publication, which used only 16.7 pb-1 of electron–proton collisions and 65.1 pb-1 of positron–proton collisions, is achieved, owing to the large data sample and improved kinematic reconstruction methods. The measurement is well-described by different theory predictions.
Measurement of the luminosity in the ZEUS experiment at HERA II
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.
A Note on the 'Hellenic League against Persia' and the Sanctuary of Zeus at Nemea
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...... of the neutral stance taken by both Kleonai and Argos during the invasion - which, if accepted, will also mean that the close relations between Kleonai and Argos began prior to 480 BC....
Precision calculation of processes used for luminosity measurement at the ZEUS experiment
Haas, T
2010-01-01
The process pe -> pe+gamma 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 gamma-e coincidence are analyzed. We also calculate the process pe -> pel+l- which contributes to the background in the electron tagger.
Production of Ξ{sup −} in deep inelastic scattering with ZEUS detector at HERA
Nasir, N. Mohammad, E-mail: atikahnasir91@siswa.um.edu.my; Wan Abdullah, W. A. T., E-mail: wat@um.edu.my [National Centre for Particle Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia)
2016-01-22
In this paper, we discussed about the possible mechanism on how strange baryon are being produced. The discovery of strange quarks in cosmic rays before the quarks model being proposed makes the searches become more interesting, as it has long lifetimes. The inclusive deep inelastic scattering of Ξ{sup −} has been studied in electron-proton collisions with ZEUS detector at HERA. We also studied HERA kinematics and phase space.
The Design and Performance of the ZEUS Central Tracking Detector z-by-Timing System
Bailey, D S; Foster, B; Harnew, N; Heath, G P; Jeffs, M D; Khatri, T; Lancaster, M; Lane, J B; McArthur, I C; McFall, J D; Milborrow, R S; Morgado, C J S; Morrissey, M; Nash, J; Nixon, G; Phillips, D A; Postranecky, M; Quinton, S P H; Shield, P D; Topp-Jørgensen, S; Westlake, G; White, D J; Wilson, F F
1997-01-01
The ZEUS Central Tracking Detector utilizes a time difference measurement to provide a fast determination of the z-coordinate of each hit. The z-by-timing measurement is achieved by using a Time-to-Amplitude Converter which has an intrinsic timing resolution of 36 ps, has pipelined readout, and has a multihit capability of 48 ns. In order to maintain the required sub-nanosecond timing accuracy, the technique incorporates an automated self-calibration system. The readout of the z-by-timing data utilizes a fully customized timing control system which runs synchronously with the HERA beam-crossing clock, and a data acquisition system implemented on a network of Transputers. Three dimensional space-points provided by the z-by-timing system are used as input to all three levels of the ZEUS trigger and for offline track reconstruction. The average z-resolution is determined to be 4.4 cm for multi-track events from positron-proton collisions in the ZEUS detector.
Performance of the CLAS12 Silicon Vertex Tracker modules
Antonioli, Mary Ann [JLAB; Boiarinov, Serguie; Bonneau, Peter R. [JLAB; Elouadrhiri, Latifa [JLAB; Eng, Brian J. [JLAB; Gotra, Yuri N. [JLAB; Kurbatov, Evgeny O. [Moscow State U.; Leffel, Mindy A. [JLAB; Mandal, Saptarshi [JLAB; McMullen, Marc E. [JLAB; Merkin, Mikhail M. [Moscow State U.; Raydo, Benjamin J. [JLAB; Teachey, Robert W, [JLAB; Tucker, Ross J. [Arizona State U.; Ungaro, Maurizio [JLAB; Yegneswaran, Amrit S. [JLAB; Ziegler, Veronique [JLAB
2013-12-01
For the 12 GeV upgrade, the CLAS12 experiment has designed a Silicon Vertex Tracker (SVT) using single sided microstrip sensors fabricated by Hamamatsu. The sensors have graded angle design to minimize dead areas and a readout pitch of 156{micro}m, with intermediate strip. Double sided SVT module hosts three daisy-chained sensors on each side with a full strip length of 33 cm. There are 512 channels per module read out by four Fermilab Silicon Strip Readout (FSSR2) chips featuring data driven architecture, mounted on a rigid-flex hybrid. Modules are assembled on the barrel using unique cantilevered geometry to minimize the amount of material in the tracking volume. Design and performance of the SVT modules are presented, focusing on results of electrical measurements.
A Cubic Kernel for Feedback Vertex Set
Bodlaender, H.L.
2006-01-01
The FEEDBACK VERTEX SET problem on unweighted, undirected graphs is considered. Improving upon a result by Burrage et al. [7], we show that this problem has a kernel with O(κ3) vertices, i.e., there is a polynomial time algorithm, that given a graph G and an integer κ, finds a graph G' and integer
Vertex Algebra Sheaf Structure on Torus
SUN Yuan-yuan
2016-01-01
In this paper, we first give a 1-1 corresponds between torus C/Λand cubic curve C in P2C. As complex manifold, they are isomorphic, therefore we can treat C/Λas a variety and construction a vertex algebra sheaf on it.
Redford, S
2014-01-01
In order to achieve its primary objectives of heavy-flavour tagging and tau lepton identification, the CLIC vertex detector must precisely reconstruct displaced vertices. This re- quires accurate determination of the impact parameter and charge of tracks originating from the secondary vertex. Excellent spatial resolution must therefore be provided down to low polar angles, whilst maintaining low occupancy, low mass and low power dissipation. These requirements chal- lenge current technological limits, and demand a broad programme of R&D. A detector concept is currently under development, comprising a hybrid pixel detector of small-pitch readout ASICs implemented in 65nm CMOS technology (CLICpix) combined with ultra-thin sensors. The read- out chips are low-power, and power-pulsing is used to reduce further their power dissipation. This enables a forced gas cooling system in the vertex detector region. In this paper, the CLIC vertex detector requirements are reviewed and the current status of R&D on se...
Primary Vertex Reconstruction at the ATLAS Experiment
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...
Battaglia, Marco; Bussat, Jean-Marie; Contarato, Devis; Denes,Peter; Glesener, Lindsay; Greiner, Leo; Hooberman, Benjamin; Shuman,Derek; Tompkins, Lauren; Vu, Chinh; Bisello, Dario; Giubilato, Piero; Pantano, Devis; Costa, Marco; La Rosa, Alessandro; Bolla, Gino; Bortoletto, Daniela; Children, Isaac
2007-10-01
This document summarizes past achievements, current activities and future goals of the R&D program aimed at the design, prototyping and characterization of a full detector module, equipped with monolithic pixel sensors, matching the requirements for the Vertex Tracker at the ILC. We provide a plan of activities to obtain a demonstrator multi-layered vertex tracker equipped with sensors matching the ILC requirements and realistic lightweight ladders in FY11, under the assumption that ILC detector proto-collaborations will be choosing technologies and designs for the Vertex Tracker by that time. The R&D program discussed here started at LBNL in 2004, supported by a Laboratory Directed R&D (LDRD) grant and by funding allocated from the core budget of the LBNL Physics Division and from the Department of Physics at UC Berkeley. Subsequently additional funding has been awarded under the NSF-DOE LCRD program and also personnel have become available through collaborative research with other groups. The aim of the R&D program carried out by our collaboration is to provide a well-integrated, inclusive research effort starting from physics requirements for the ILC Vertex Tracker and addressing Si sensor design and characterization, engineered ladder design, module system issues, tracking and vertex performances and beam test validation. The broad scope of this program is made possible by important synergies with existing know-how and concurrent programs both at LBNL and at the other collaborating institutions. In particular, significant overlaps with LHC detector design, SLHC R&D as well as prototyping for the STAR upgrade have been exploited to optimize the cost per deliverable of our program. This activity is carried out as a collaborative effort together with Accelerator and Fusion Research, the Engineering and the Nuclear Science Divisions at LBNL, INFN and the Department of Physics in Padova, Italy, INFN and the Department of Physics in Torino, Italy and the Department
CLIQUE IRREDUCIBILITY AND CLIQUE VERTEX IRREDUCIBILITY OF GRAPHS
Vijayakumar, A.; Aparna Lakshmanan S.
2009-01-01
A graphs G is clique irreducible if every clique in G of size at least two, has an edge which does not lie in any other clique of G and is clique reducible if it is not clique irreducible. A graph G is clique vertex irreducible if every clique in G has a vertex which does not lie in any other clique of G and clique vertex reducible if it is not clique vertex irreducible. The clique vertex irreducibility and clique irreducibility of graphs which are non-complete extended p-sums (NEPS) of two g...
Optimized Vertex Method and Hybrid Reliability
Smith, Steven A.; Krishnamurthy, T.; Mason, B. H.
2002-01-01
A method of calculating the fuzzy response of a system is presented. This method, called the Optimized Vertex Method (OVM), is based upon the vertex method but requires considerably fewer function evaluations. The method is demonstrated by calculating the response membership function of strain-energy release rate for a bonded joint with a crack. The possibility of failure of the bonded joint was determined over a range of loads. After completing the possibilistic analysis, the possibilistic (fuzzy) membership functions were transformed to probability density functions and the probability of failure of the bonded joint was calculated. This approach is called a possibility-based hybrid reliability assessment. The possibility and probability of failure are presented and compared to a Monte Carlo Simulation (MCS) of the bonded joint.
On the plane-wave cubic vertex
Lucietti, J; Sinha, A K; Lucietti, James; Schäfer-Nameki, Sakura; Sinha, Aninda
2004-01-01
The exact bosonic Neumann matrices of the cubic vertex in plane-wave light-cone string field theory are derived using the contour integration techniques developed in our earlier paper. This simplifies the original derivation of the vertex. In particular, the Neumann matrices are written in terms of \\mu-deformed Gamma-functions, thus casting them into a form that elegantly generalizes the well-known flat-space solution. The asymptotics of the \\mu-deformed Gamma-functions allow one to determine the large-\\mu behaviour of the Neumann matrices including exponential corrections. We provide an explicit expression for the first exponential correction and make a conjecture for the subsequent exponential correction terms.
Hypergraph Partitioning through Vertex Separators on Graphs
Kayaaslan, Enver; Catalyurek, Umit V; Aykanat, Cevdet
2011-01-01
The modeling flexibility provided by hypergraphs has drawn a lot of interest from the combinatorial scientific community, leading to novel models and algorithms, their applications, and development of associated tools. Hypergraphs are now a standard tool in combinatorial scientific computing. The modeling flexibility of hypergraphs however, comes at a cost: algorithms on hypergraphs are inherently more complicated than those on graphs, which sometimes translate to nontrivial increases in processing times. Neither the modeling flexibility of hypergraphs, nor the runtime efficiency of graph algorithms can be overlooked. Therefore, the new research thrust should be how to cleverly trade-off between the two. This work addresses one method for this trade-off by solving the hypergraph partitioning problem by finding vertex separators on graphs. Specifically, we investigate how to solve the hypergraph partitioning problem by seeking a vertex separator on its net intersection graph (NIG), where each net of the hyperg...
Vertex Reconstruction and Performance in ATLAS
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.
Nonperturbative Aspects of Axial Vector Vertex
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.
Bimodules associated to vertex operator superalgebras
2008-01-01
Let V be a vertex operator superalgebra and m,n ∈ 21Z+. We construct an An(V ) -Am(V )-bimodule An,m(V ) which characterizes the action of V from the level m subspace to level n subspace of an admissible V -module. We also construct the Verma type admissible V -module from an Am(V )-module by using bimodules
Primary vertex reconstruction with the ATLAS detector
Meloni, Federico; The ATLAS collaboration
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.
Silicon technologies for the CLIC vertex detector
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.
B Decay Charm Counting Via Topological Vertexing
Chou, Aaron Sze Ting
2002-01-01
We present a new and unique measurement of the branching fractions of b hadrons to states with 0, 1, and 2 open charm hadrons, using a sample of 350,000 hadronic Z0 decays collected during the SLD/SLC 97–98 run. The analysis takes advantage of the excellent vertexing resolution of the VXD3, a pixel-based CCD vertex detector, which allows the separation of B and cascade D decay vertices. A fit of the vertex count and the decay length distributions to distribution shapes predicted by Monte Carlo simulation allows the extraction of the inclusive branching fractions. We measure: BRB→0D X=3.7±1.1 stat±2.1 syst% BRB→2D X=17.9±1.4 stat±3.3 syst% where B, and D represent mixtures of open b and open c hadrons. The corresponding charm count, Nc = 1.188 ± 0.010 ± 0.040 ± 0.006 is consistent with previous measurement averages but slightly closer to theoretical expectations.
Nonperturbative study of the four gluon vertex
Binosi, D; Papavassiliou, J
2014-01-01
In this paper we study the nonperturbative structure of the SU(3) four-gluon vertex in the Landau gauge, concentrating on contributions quadratic in the metric. We employ an approximation scheme where "one-loop" diagrams are computed using fully dressed gluon and ghost propagators, and tree-level vertices. When a suitable kinematical configuration depending on a single momentum scale $p$ is chosen, only two structures emerge: the tree-level four-gluon vertex, and a tensor orthogonal to it. A detailed numerical analysis reveals that the form factor associated with this latter tensor displays a change of sign (zero-crossing) in the deep infrared, and finally diverges logarithmically. The origin of this characteristic behavior is proven to be entirely due to the masslessness of the ghost propagators forming the corresponding ghost-loop diagram, in close analogy to a similar effect established for the three-gluon vertex. However, in the case at hand, and under the approximations employed, this particular divergen...
B Decay Charm Counting via Topological Vertexing
Chou, Aaron S
2001-10-15
We present a new and unique measurement of the branching fractions of b hadrons to states with 0, 1, and 2 open charm hadrons, using a sample of 350,000 hadronic Z{sup 0} decays collected during the SLD/SLC 97-98 run. The method takes advantage of the excellent vertexing resolution of the VXD3, a pixel-based CCD vertex detector, which allows the separation of B and cascade D decay vertices. A fit of the vertex count and the decay length distributions to distribution shapes predicted by Monte Carlo simulation allows the extraction of the inclusive branching fractions. We measure: BR(B {yields} (0D)X) = (3.7{+-}1.1(stat) {+-} 2.1(syst))%; and BR(B {yields} (2D)X) = (17.9{+-}1.4(stat) {+-} 3.3(syst))% where B and D represent mixtures of open b and open c hadrons. The corresponding charm count, N{sub c} = 1.188 {+-} 0.010 {+-} 0.040 {+-} 0.006 is consistent with previous measurement averages but slightly closer to theoretical expectations.
Spin wave Feynman diagram vertex computation package
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.
Silicon Technologies for the CLIC Vertex Detector
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...
Data analysis of the ZEUS forward plug calorimeter beam test at CERN
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
Computer-enhanced thoracoscopic thymectomy with the Zeus telemanipulation surgical system.
Berman, Marius; Stamler, Alon; Vidne, Bernardo A; Saute, Milton
2003-09-01
Recent years have witnessed important progress in the use of minimally invasive robotic-enhanced surgical systems in cardiac and general thoracic interventions. We report the first-ever successful use of the Zeus robotic surgical system (Computer Motion, Inc, Goleta, CA) for the excision of an anterior mediastinal mass. Proper positioning of the thoracic ports for the robotic arms to permit a wide range of movement, is the key to the application of the system for intrathoracic cage operations. Other advantages of the system include three-dimensional voice controlled imaging, low-heat surgical field, and good exposure of the structures.
Precision calculation of processes used for luminosity measurement at the ZEUS experiment
Haas, T. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Makarenko, V. [NCPHEP, Minsk (Belarus)
2010-09-15
The process pe{sup {+-}} {yields} pe{sup {+-}}{gamma} 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 {gamma}-e coincidence are analyzed. We also calculate the process pe{sup {+-}} {yields} pe{sup {+-}}l{sup -}l{sup +} which contributes to the background in the electron tagger. (orig.)
Precision calculation of processes used for luminosity measurement at the ZEUS experiment
Haas, T. [DESY, Hamburg (Germany); Makarenko, V. [NCPHEP, Minsk (Belarus)
2011-03-15
The process pe {sup {+-}}{yields}pe{sup {+-}}{gamma} 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 {gamma}-e coincidence are analyzed. We also calculate the process pe{sup {+-}}{yields}pe {sup {+-}}l{sup -}l{sup +} which contributes to the background in the electron tagger. (orig.)
Pozniak, Krzysztof T.
2004-07-01
The paper describes design and construction of hardware diagnostics layer dedicated to the local trigger of the Backing Calorimeter (BAC). The BAC is a part of the ZEUS experiment in DESY, Hamburg. A general characteristic of the hardware of BAC trigger was presented. The design of hardware diagnostic and calibration sub-systems for BAC trigger bases on the continuous monitoring of consecutive electronic and photonic blocks. The monitoring process is performed via the specialized tests. The standardized diagnostic components were realized in the algorithmic and parameterized description in AHDL. There were presented the implementation results in ALTERA ACEX chips.
Photoproduction of events with rapidity gaps between jets with ZEUS at HERA
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.)
Iluminar obras de arte mejorando la conservación. El proyecto Zeus
Benítez, Anton J.; Vázquez Moliní, Daniel; Álvarez Fernández-Balbuena, Antonio
2015-01-01
La iluminación de obras de arte se enfrenta al reto de resultar adecuada para la exhibición y de minimizar en lo posible los daños a la superficie y los materiales que las componen. En esta encrucijada, en la que la investigación es imprescindible tanto en tecnología como acerca de la recepción por parte del público, el proyecto Zeus trata de obtener una precisa información sobre el color de la obra, y trasladarla a un modelo de iluminación individualizado punto a punto, que permite simular c...
Iluminar obras de arte mejorando la conservación. Proyecto Zeus
Benítez, Anto J.; Daniel Vázquez Moliní; Antonio Álvarez Fernández
2016-01-01
La iluminación de obras de arte se enfrenta al reto de resultar adecuada para la exhibición y de minimizar en lo posible los daños a la su- perficie y los materiales que las componen. En esta encrucijada, en la que la investigación es imprescindible tanto en tecnología como acerca de la recepción por parte del público, el proyecto Zeus trata de obtener una precisa información sobre el color de la obra, y trasladarla a un modelo de iluminación individualizado punto a punto, que permite simular...
Deep inelastic cross-section measurements at large y with the ZEUS detector at HERA
Abramowicz, H; Adamczyk, L; Adamus, M; Aggarwal, R; Antonelli, S; Arslan, O; Aushev, V; Aushev, Y; Bachynska, O; Barakbaev, A N; Bartosik, N; Behnke, O; Behr, J; Behrens, U; Bertolin, A; Bhadra, S; Bloch, I; Bokhonov, V; Boos, E G; Borras, K; Brock, I; Brugnera, R; Bruni, A; Brzozowska, B; Bussey, P J; Caldwell, A; Capua, M; Catterall, C D; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cooper-Sarkar, A M; Corradi, M; Corriveau, F; D'Agostini, G; Dementiev, R K; Devenish, R C E; Dolinska, G; Drugakov, V; Dusini, S; Ferrando, J; Figiel, J; Foster, B; Gach, G; Garfagnini, A; Geiser, A; Gizhko, A; Gladilin, L K; Gogota, O; Golubkov, Yu A; Grebenyuk, J; Gregor, I; Grzelak, G; Gueta, O; Guzik, M; Hain, W; Hartner, G; Hochman, D; Hori, R; Ibrahim, Z A; Iga, Y; Ishitsuka, M; Iudin, A; Januschek, F; Kadenko, I; Kananov, S; Kanno, T; Karshon, U; Kaur, M; Kaur, P; Khein, L A; Kisielewska, D; Klanner, R; Klein, U; Kondrashova, N; Kononenko, O; Korol, Ie; Korzhavina, I A; Kotanski, A; Kotz, U; Kovalchuk, N; Kowalski, H; Kuprash, O; Kuze, M; Levchenko, B B; Levy, A; Libov, V; Limentani, S; Lisovyi, M; Lobodzinska, E; Lohmann, W; Lohr, B; Lohrmann, E; Longhin, A; Lontkovskyi, D; Lukina, O Yu; Maeda, J; Makarenko, I; Malka, J; Martin, J F; Mergelmeyer, S; Idris, F Mohamad; Mujkic, K; Myronenko, V; Nagano, K; Nigro, A; Nobe, T; Notz, D; Nowak, R J; Olkiewicz, K; Onishchuk, Yu; Paul, E; Perlanski, W; Perrey, H; Pokrovskiy, N S; Proskuryakov, A S; Przybycien, M; Raval, A; Roloff, P; Rubinsky, I; Ruspa, M; Samojlov, V; Saxon, D H; Schioppa, M; Schmidke, W B; Schneekloth, U; Schorner-Sadenius, T; Schwartz, J; Shcheglova, L M; Shevchenko, R; Shkola, O; Singh, I; Skillicorn, I O; Slominski, W; Sola, V; Solano, A; Spiridonov, A; Stanco, L; Stefaniuk, N; Stern, A; Stewart, T P; Stopa, P; Sztuk-Dambietz, J; Szuba, D; Szuba, J; Tassi, E; Temiraliev, T; Tokushuku, K; Tomaszewska, J; Trofymov, A; Trusov, V; Tsurugai, T; Turcato, M; Turkot, O; Tymieniecka, T; Verbytskyi, A; Viazlo, O; Walczak, R; Abdullah, W A T Wan; Wichmann, K; Wing, M; Wolf, G; Yamada, S; Yamazaki, Y; Zakharchuk, N; Zarnecki, A F; Zawiejski, L; Zenaiev, O; Zhautykov, B O; Zhmak, N; Zotkin, D S
2014-01-01
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 $0.13\\ \\leq\\ y\\ \\leq\\ 0.75$, where $y$ denotes the inelasticity and $5\\ \\leq\\ Q^2\\ \\leq\\ 110$ GeV$^2$. The proton structure functions $F_2$ and $F_L$ were extracted from the measured cross sections.
A discriminator with a current-sum multiplicity output for the PHENIX multiplicity vertex detector
Smith, R.S.; Kennedy, E.J.; Jackson, R.G. [Univ. of Tennessee, Knoxville, TN (United States)
1996-12-01
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 {micro}W from a single 5-V supply. Details of the design and results from prototype device testing are presented.
Han-Xin Zhou; Yue-Hua Guo; Xiao-Fang Yu; Shi-Yun Bao; Jia-Lin Liu; Yue Zhang; Yong-Gong Ren; Qun Zheng
2006-01-01
AIM: To summarize the performing essentials and analyze the characteristics of remote Zeus robot-assisted laparoscopic cholecystectomy.METHODS: Robot-assisted laparoscopic cholecystectomy was performed in 40 patients between May 2004 and July 2005. The operating procedures and a variety of clinical parameters were recorded and analyzed.RESULTS: Forty laparoscopic cholecystectomy procedures were successfully completed with Zeus robotic system. And there were no post-operative complications. Total operating time, system setup time and performing time were 100.3±18.5 min, 27.7±8.8 min and 65.6±18.3 min, respectively. The blood loss and postoperative hospital stay were 30.6±10.2 mL and 2.8±0.8d, respectively. Camera clearing times and time used for operative field adjustment were 1.1 ± 1.0 min and 2.0± 0.8min, respectively. The operative error was 7.5%.CONCLUSION: Robot-assisted laparoscopic cholecystectomy following the principles of laparoscopic operation has specific performing essentials. It preserves the benefits of minimally invasive surgery and offers enhanced ability of controlling operation field, precise and stable operative manipulations.
Zhou, Han-Xin; Guo, Yue-Hua; Yu, Xiao-Fang; Bao, Shi-Yun; Liu, Jia-Lin; Zhang, Yue; Ren, Yong-Gong; Zheng, Qun
2006-04-28
To summarize the performing essentials and analyze the characteristics of remote Zeus robot-assisted laparoscopic cholecystectomy. Robot-assisted laparoscopic cholecystectomy was performed in 40 patients between May 2004 and July 2005. The operating procedures and a variety of clinical parameters were recorded and analyzed. Forty laparoscopic cholecystectomy procedures were successfully completed with Zeus robotic system. And there were no post-operative complications. Total operating time, system setup time and performing time were 100.3 +/- 18.5 min, 27.7 +/- 8.8 min and 65.6 +/- 18.3 min, respectively. The blood loss and post-operative hospital stay were 30.6 +/- 10.2 mL and 2.8 +/- 0.8 d, respectively. Camera clearing times and time used for operative field adjustment were 1.1+/- 1.0 min and 2.0 +/- 0.8 min, respectively. The operative error was 7.5%. Robot-assisted laparoscopic cholecystectomy following the principles of laparoscopic operation has specific performing essentials. It preserves the benefits of minimally invasive surgery and offers enhanced ability of controlling operation field, precise and stable operative manipulations.
The Belle II Silicon Vertex Detector
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.
Extended technicolor contribution to the Zbb vertex
Hagiwara, K; Hagiwara, Kaoru; Kitazawa, Noriaki
1995-01-01
We show that the flavor-diagonal gauge boson of the extended technicolor theory contributes with opposite sign to the standard model correction for the Zbb vertex. This mechanism can naturally explain the deviation of the LEP result from the standard model prediction for the partial width \\Gamma(Z \\rightarrow b{\\bar b}). A smaller value of the QCD coupling, \\alpha_s(m_Z) \\simeq 0.115, is then preferred by the \\Gamma(Z \\rightarrow \\mbox{hadron}) data, which is consistent with both the recent Lattice-QCD estimate and the Particle Data Group average.
The Mark II Vertex Drift Chamber
Alexander, J.P.; Baggs, R.; Fujino, D.; Hayes, K.; Hoard, C.; Hower, N.; Hutchinson, D.; Jaros, J.A.; Koetke, D.; Kowalski, L.A.
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 {mu}m spatial resolution and <1000 {mu}m track-pair resolution in pressurized CO{sub 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{sub 2} mixtures are presented. 10 refs., 12 figs., 1 tab.
On the vertex index of convex bodies
Bezdek, Karoly
2011-01-01
We introduce the vertex index, vein(K), of a given centrally symmetric convex body K, which, in a sense, measures how well K can be inscribed into a convex polytope with small number of vertices. This index is closely connected to the illumination parameter of a body, introduced earlier by the first named author, and, thus, related to the famous conjecture in Convex Geometry about covering of a d-dimensional body by 2^d smaller positively homothetic copies. We provide asymptotically sharp estimates (up to a logarithmic term) of this index in the general case. Also, we provide sharp estimates in dimensions 2 and 3.
Radiation damage in the LHCb Vertex Locator
Affolder, A; Akiba, K.; Alexander, M.; Ali, S.; Artuso, M.; Benton, J.; van Beuzekom, M.; Bjørnstad, P M; Bogdanova, G; Borghi, S.; Bowcock, T. J. V.; Brown, H.; Buytaert, J.; Casse, G.; Collins, P.
2013-01-01
The LHCb Vertex Locator (VELO) is a silicon strip detector designed to reconstruct charged particle trajectories and vertices produced at the LHCb interaction region. During the first two years of data collection, the 84 VELO sensors have been exposed to a range of fluences up to a maximum value of approximately $\\rm{45 \\times 10^{12}\\,1\\,MeV}$ neutron equivalent ($\\rm{1\\,MeV\\,n_{eq}}$). At the operational sensor temperature of approximately $-7\\,^{\\circ}\\rm{C}$, the average rate of sensor cu...
Laursen, Johnny
Dette bind redegør for den yderste højrefløj og PET's overvågning af grupperinger og partier inden for dette felt. Undersøgelsen, som er kronologisk og tematisk opbygget, tegner et billede af nazismens og den yderste højrefløjs udvikling fra 1945 til 1989. Der redegøres udførligt for PET's overvå...
Quasi-lisse vertex algebras and modular linear differential equations
Arakawa, Tomoyuki
2016-01-01
We introduce a notion of quasi-lisse vertex algebras, which generalizes admissible affine vertex algebras. We show that the normalized character of an ordinary module over a quasi-lisse vertex operator algebra has a modular invariance property, in the sense that it satisfies a modular linear differential equation. As an application we obtain the explicit character formulas of simple affine vertex algebras associated with the Deligne exceptional series at level $-h^{\\vee}/6-1$, which expresses the homogeneous Schur limit of the superconformal index of 4d SCFTs studied by Beem, Lemos, Liendo, Peelaers, Rastelli and van Rees, as quasi-modular forms.
Markov branching in the vertex splitting model
Stefansson, Sigurdur Orn
2011-01-01
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 $\\alpha \\in [0,1]$ which has a so--called Markov branching property. When $D=\\infty$ we find a two parameter model with an additional parameter $\\gamma \\in [0,1]$ which also has this feature. In the case $D = 3$, the model bears resemblance to Ford's $\\alpha$--model of phylogenetic trees and when $D=\\infty$ it is similar to its generalization, the $\\alpha\\gamma$--model. For $\\alpha = 0$, the model reduces to the well known model of preferential attachment. In the case $\\alpha > 0$, 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 $1/\\alpha$. When $\\gamma = 0$ the model reduces to a model of ...
The Construction of Spin Foam Vertex Amplitudes
Bianchi, Eugenio
2012-01-01
Spin foam vertex amplitudes are the key ingredient of spin foam models for quantum gravity. They 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 Barret and Crane and 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.
The LHCb level 1 vertex trigger
Koratzinos, M
1999-01-01
Summary form only given. The Level 1 Vertex trigger of LHCb has certain features that make it unique amongst the LHC experiment trigger schemes: The problem it addresses is a reduction factor of 25 for minimum bias events while retaining good efficiency for signal B events. The best way to achieve such reduction factors is to rely on the most striking property of those B events, the long decay time of the B particles. The trigger therefore has to reconstruct the event around the interaction region and tag signal events using topological criteria. An accurate vertex detector is one of the key components of LHCb and a natural choice for providing the data for such a triggering scheme. The algorithm for the reconstruction of the event is complicated and not readily parallelisable in its totality. We are therefore proposing an architecture that resembles a high-level trigger architecture, where the event building function is performed by a switch network and each event is processed by a single processor, part of ...
Vertexing and Tracking Software at Belle II
Schlüter, Tobias
2014-01-01
Belle II is a $B$ factory experiment aiming to start physics data taking in 2017. It is currently being set up at the SuperKEKB accelerator at the KEK facility in Tsukuba (Japan), an asymmetric $e^+e^-$ collider which aims to achieve an unprecedented instantaneous luminosity of $8\\cdot10^{35} \\textrm{Hz}/\\textrm{cm}^2$. This forty-fold increase over predecessor experiments is achieved by employing a novel nano-beam scheme. Originally developed for the now-defunct SuperB experiment, this scheme allows a significant increase in luminosity at only modest increases of beam currents. Challenges for the vertex detector result from increased data and background rates. At full luminosity, physics data will be recorded at a rate of $30\\,\\textrm{kHz}$. The radiation-hard DEPFET-sensors of the innermost layer of the vertex detector will be read out employing a novel data-reduction scheme using selective detector read out based on online reconstruction of event data. Belle II uses a software framework in which data handl...
The Construction of Spin Foam Vertex Amplitudes
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.
Vertex Sparsifiers and Abstract Rounding Algorithms
Charikar, Moses; Li, Shi; Moitra, Ankur
2010-01-01
The notion of vertex sparsification is introduced in \\cite{M}, where it was shown that for any graph $G = (V, E)$ and a subset of $k$ terminals $K \\subset V$, there is a polynomial time algorithm to construct a graph $H = (K, E_H)$ on just the terminal set so that simultaneously for all cuts $(A, K-A)$, the value of the minimum cut in $G$ separating $A$ from $K -A$ is approximately the same as the value of the corresponding cut in $H$. We give the first super-constant lower bounds for how well a cut-sparsifier $H$ can simultaneously approximate all minimum cuts in $G$. We prove a lower bound of $\\Omega(\\log^{1/4} k)$ -- this is polynomially-related to the known upper bound of $O(\\log k/\\log \\log k)$. This is an exponential improvement on the $\\Omega(\\log \\log k)$ bound given in \\cite{LM} which in fact was for a stronger vertex sparsification guarantee, and did not apply to cut sparsifiers. Despite this negative result, we show that for many natural problems, we do not need to incur a multiplicative penalty fo...
Measurement of beauty production in DIS and F-2(b(b)over-bar) extraction at ZEUS
Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Aushev, V.; Aushev, Y.; Bachynska, O.; Bamberger, A.; Barakbaev, A. N.; Barbagli, G.; Bari, G.; Barreiro, F.; Bartsch, D.; Basile, M.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Bertolin, A.; Bhadra, S.; Bindi, M.; Blohm, C.; Bold, T.; Boos, E. G.; Borodin, M.; Borras, K.; Boscherini, D.; Boutle, S. K.; Brock, I.; Brownson, E.; Brugnera, R.; Bruemmer, N.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bussey, P. J.; Butterworth, J. M.; Bylsma, B.; Caldwell, A.; Capua, M.; Carlin, R.; Catterall, C. D.; Chekanov, S.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Cooper-Sarkar, A. M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; D'Agostini, G.; Dal Corso, F.; de Favereau, J.; del Peso, J.; Dementiev, R. K.; De Pasquale, S.; Derrick, M.; Devenish, R. C. E.; Dobur, D.; Dolgoshein, B. A.; Doyle, A. T.; Drugakov, V.; Durkin, L. S.; Dusini, S.; Eisenberg, Y.; Ermolov, P. F.; Eskreys, A.; Fazio, S.; Ferrando, J.; Ferrero, M. I.; Figiel, J.; Forrest, M.; Foster, B.; Fourletov, S.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gialas, I.; Gladilin, L. K.; Gladkov, D.; Glasman, C.; Gogota, O.; Golubkov, Yu. A.; Goettlicher, P.; Grabowska-Bold, I.; Grebenyuk, J.; Gregor, I.; Grigorescu, G.; Grzelak, G.; Gwenlan, C.; Haas, T.; Hain, W.; Hamatsu, R.; Hart, J. C.; Hartmann, H.; Hartner, G.; Hilger, E.; Hochman, D.; Holm, U.; Hori, R.; Horton, K.; Huettmann, A.; Iacobucci, G.; Ibrahim, Z. A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Jakob, H. -P.; Januschek, F.; Jimenez, M.; Jones, T. W.; Juengst, M.; Kadenko, I.; Kahle, B.; Kamaluddin, B.; Kananov, S.; Kanno, T.; Karshon, U.; Karstens, F.; Katkov, I. I.; Kaur, M.; Kaur, P.; Keramidas, A.; Khein, L. A.; Kim, J. Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, U.; Kollar, D.; Kooijman, P.; Korol, Ie.; Korzhavina, I. A.; Kotanski, A.; Koetz, U.; Kowalski, H.; Kulinski, P.; Kuprash, O.; Kuze, M.; Kuzmin, V. A.; Lee, A.; Levchenko, B. B.; Libov, V.; Limentani, S.; Ling, T. Y.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Loehr, B.; Lohrmann, E.; Loizides, J. H.; Long, K. R.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; Luzniak, P.; Maeda, J.; Magill, S.; Makarenko, I.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Mastroberardino, A.; Matsumoto, T.; Mattingly, M. C. K.; Melzer-Pellmann, I. -A.; Miglioranzi, S.; Idris, F. Mohamad; Monaco, V.; Montanari, A.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Nicholass, D.; Nigro, A.; Ning, Y.; Noor, U.; Notz, D.; Nowak, R. J.; Nuncio-Quiroz, A. E.; Oh, B. Y.; Okazaki, N.; Oliver, K.; Olkiewicz, K.; Onishchuk, Yu.; Ota, O.; Papageorgiu, K.; Parenti, A.; Pawlak, J. M.; Pawlik, B.; Pelfer, P. G.; Pellegrino, A.; Perlanski, W.; Perrey, H.; Piotrzkowski, K.; Plucinski, P.; Pokrovskiy, N. S.; Polini, A.; Proskuryakov, A. S.; Przybycien, M.; Raval, A.; Reeder, D. D.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y. D.; Robertson, A.; Roloff, P.; Ron, E.; Rubinsky, I.; Ruspa, M.; Sacchi, R.; Salii, A.; Samson, U.; Sartorelli, G.; Savin, A. A.; Saxon, D. H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W. B.; Schneekloth, U.; Schoenberg, V.; Schoerner-Sadenius, T.; Schwartz, J.; Sciulli, F.; Shcheglova, L. M.; Shehzadi, R.; Singh, I.; Skillicorn, I. O.; Slominski, W.; Smith, W. H.; Sola, V.; Solano, A.; Son, D.; Sosnovtsev, V.; Spiridonov, A.; Stadie, H.; Stanco, L.; Stern, A.; Stewart, T. P.; Stifutkin, A.; Stopa, P.; Suchkov, S.; Susinno, G.; Suszycki, L.; Sztuk, J.; Szuba, D.; Szuba, J.; Tapper, A. D.; Tassi, E.; Terron, J.; Theedt, T.; Tiecke, H.; Tokushuku, K.; Tomalak, O.; Tomaszewska, J.; Tsurugai, T.; Turcato, M.; Tymieniecka, T.; Uribe-Estrada, C.; Vazquez, M.; Verbytskyi, A.; Viazlo, V.; Vlasov, N. N.; Volynets, O.; Walczak, R.; Abdullah, W. A. T. Wan; Whitmore, J. J.; Whyte, J.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Yaguees-Molina, A. G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Zarnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhautykov, B. O.; Zhmak, N.; Zichichi, A.; Zolko, M.; Zotkin, D. S.; Zulkapli, Z.
2010-01-01
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 distribut
Luszczak, Zbigniew; Jezynski, Tomasz; Romaniuk, Ryszard S.; Pozniak, Krzysztof T.; Kuthan, Marcin; Bigos, Grzegorz; Gierej, Artur
2003-10-01
The paper presents functional structure of database system of data measurement quality for BAC detector in ZEUS experiment. The system collects diagnostic and experimental data. Diagnostic data are: work parameters of the detector and electronics/photonics, tests of electronic/photonic blocks. These data are archived for certain period of time. The quality of current data collection process is estimated using these archived data. The result of such estimation is generated in a form of status map of the detector. Such maps, describing status of the hardware, are fundamental for elementary particle analysis by the calorimeter. The DAQ system, collecting data to the database, estimates data quality on-line during transmission and writing. This mechanism of fast on-line data quality management leads to early discoveries of detector work irregularities and faults.
Brock, Ian C.; Shehzadi, Ramoona; Juengst, Markus [Physikalisches Institut, University of Bonn (Germany); Roloff, Philipp; Libov, Vladyslav [DESY, Hamburg (Germany); University of Hamburg (Germany)
2011-07-01
The study of heavy flavour production in ep collisions is one of the main research topics at HERA. In two recent analyses the production of heavy quarks in deep inelastic scattering has been studied with the ZEUS detector using the full HERA II dataset. In one of these analyses, the heavy flavour events were identified using electrons from semileptonic decays. The fractions of events containing the heavy quarks were extracted from a likelihood fit using variables sensitive to electron identification as well as to semileptonic decays. In the second analysis, the heavy flavour content in events with a jet was extracted using the decay length significance and invariant mass of the secondary vertices. Total and differential cross sections were measured and compared with next-to-leading-order QCD calculations and Monte Carlo models. The beauty and charm contributions to the proton structure function F{sub 2}, were extracted from the double-differential cross sections.
Upgrade of the ZEUS OO Tag Database for Physics Analysis at HERA
U.Ericke
2001-01-01
The object-oriented tag database of the ZEUS experiment at HERA is based on Objectivity/DB.It is used to rapidly select events for physics analysis based on intuitive physical criteria.The total number of events currently in the database exceeds 150 millionBased on the detector configuration different information can be stored for each event.A new version of the database software was recently released which serves clients on a multitude of batch machines,workgroup servers and desktop machines running Irix,Linuxand Solaris.This replaces an earlier version which was restricted to three SGI machines Multiple copies of the data can be stored transparently to the users for example if a new offline reconstruction of the data is in progress.A report is given on the upgrade of the database and its superior performance compared to the old event selection method.
Operation and Optimization of a Linux PC farm for Physics Analysis in the ZEUS Experiment
KrzysztofWrona; RadekKaczorowski; 等
2001-01-01
The ZEUS experiment has migrated its reconstruction and analysis farms to a PC-based environment.More than one year of experience has been acquired with successful operation of an analysis farm designed for several hundred users.Specially designed software has been used to proveide fast and reliable access to large amounts of data (30 TB in total),After the ongoing upgrade of the HERA luminosity,higher requirements will arise in terms of data storage capacity and throughput rate,The necessity of a bigger disk cache has led to consideration of solutions based on commodity technology,PC-based file servers are being tested as a cost-effective storage system,In this article we present the hardware and software solutions deplogyed and discuss their performance.scalability and maintenance issues.
Measurement of beauty production in DIS and F_2^bbbar extraction at ZEUS
Abramowicz, H; Adamczyk, L; Adamus, M; Aggarwal, R; Antonelli, S; Antonioli, P; Antonov, A; Arneodo, M; Aushev, V; Aushev, Y; Bachynska, O; Bamberger, A; Barakbaev, A N; Barbagli, G; Bari, G; Barreiro, F; Bartsch, D; Basile, M; Behnke, O; Behr, J; Behrens, U; Bellagamba, L; Bertolin, A; Bhadra, S; Bindi, M; Blohm, C; Bold, T; Boos, E G; Borodin, M; Borras, K; Boscherini, D; Bot, D; Boutle, S K; Brock, I; Brownson, E; Brugnera, R; Bruemmer, N; Bruni, A; Bruni, G; Brzozowska, B; Bussey, P J; Butterworth, J M; Bylsma, B; Caldwell, A; Capua, M; Carlin, R; Catterall, C D; Chekanov, S; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, L; Cindolo, F; Contin, A; Cooper-Sarkar, A M; Coppola, N; Corradi, M; Corriveau, F; Costa, M; D'Agostini, G; Corso, F Dal; de Favereau, J; del Peso, J; Dementiev, R K; De Pasquale, S; Derrick, M; Devenish, R C E; Dobur, D; Dolgoshein, B A; Doyle, A T; Drugakov, V; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, A; Fang, S; Fazio, S; Ferrando, J; Ferrero, M I; Figiel, J; Forrest, M; Foster, B; Fourletov, S; Gach, G; Galas, A; Gallo, E; Garfagnini, A; Geiser, A; Gialas, I; Gladilin, L K; Gladkov, D; Glasman, C; Gogota, O; Golubkov, Yu A; Goettlicher, P; Grabowska-Bold, I; Grebenyuk, J; Gregor, I; Grigorescu, G; Grzelak, G; Gwenlan, C; Haas, T; Hain, W; Hamatsu, R; Hart, J C; Hartmann, H; Hartner, G; Hilger, E; Hochman, D; Holm, U; Hori, R; Horton, K; Huettmann, A; Iacobucci, G; Ibrahim, Z A; Iga, Y; Ingbir, R; Ishitsuka, M; Jakob, H -P; Januschek, F; Jimenez, M; Jones, T W; Juengst, M; Kadenko, I; Kahle, B; Kamaluddin, B; Kananov, S; Kanno, T; Karshon, U; Karstens, F; Katkov, I I; Kaur, M; Kaur, P; Keramidas, A; Khein, L A; Kim, J Y; Kisielewska, D; Kitamura, S; Klanner, R; Klein, U; Koffeman, E; Kollar, D; Kooijman, P; Korol, Ie; Korzhavina, I A; Kotanski, A; Koetz, U; Kowalski, H; Kulinski, P; Kuprash, O; Kuze, M; Kuzmin, V A; Lee, A; Levchenko, B B; Levy, A; Libov, V; Limentani, S; Ling, T Y; Lisovyi, M; Lobodzinska, E; Lohmann, W; Loehr, B; Lohrmann, E; Loizides, J H; Long, K R; Longhin, A; Lontkovskyi, D; Lukina, O Yu; Luzniak, P; Maeda, J; Magill, S; Makarenko, I; Malka, J; Mankel, R; Margotti, A; Marini, G; Martin, J F; Mastroberardino, A; Matsumoto, T; Mattingly, M C K; Melzer-Pellmann, I -A; Miglioranzi, S; Idris, F Mohamad; Monaco, V; Montanari, A; Morris, J D; Musgrave, B; Nagano, K; Namsoo, T; Nania, R; Nicholass, D; Nigro, A; Ning, Y; Noor, U; Notz, D; Nowak, R J; Nuncio-Quiroz, A E; Oh, B Y; Okazaki, N; Oliver, K; Olkiewicz, K; Onishchuk, Yu; Ota, O; Papageorgiu, K; Parenti, A; Paul, E; Pawlak, J M; Pawlik, B; Pelfer, P G; Pellegrino, A; Perlanski, W; Perrey, H; Piotrzkowski, K; Plucinski, P; Pokrovskiy, N S; Polini, A; Proskuryakov, A S; Przybycien, M; Raval, A; Reeder, D D; Reisert, B; Ren, Z; Repond, J; Ri, Y D; Robertson, A; Roloff, P; Ron, E; Rubinsky, I; Ruspa, M; Sacchi, R; Salii, A; Samson, U; Sartorelli, G; Savin, A A; Saxon, D H; Schioppa, M; Schlenstedt, S; Schleper, P; Schmidke, W B; Schneekloth, U; Schoenberg, V; Schoerner-Sadenius, T; Schwartz, J; Sciulli, F; Shcheglova, L M; Shehzadi, R; Shimizu, S; Singh, I; Skillicorn, I O; Slominski, W; Smith, W H; Sola, V; Solano, A; Son, D; Sosnovtsev, V; Spiridonov, A; Stadie, H; Stanco, L; Stern, A; Stewart, T P; Stifutkin, A; Stopa, P; Suchkov, S; Susinno, G; Suszycki, L; Sztuk, J; Szuba, D; Szuba, J; Tapper, A D; Tassi, E; Terron, J; Theedt, T; Tiecke, H; Tokushuku, K; Tomalak, O; Tomaszewska, J; Tsurugai, T; Turcato, M; Tymieniecka, T; Uribe-Estrada, C; Vazquez, M; Verbytskyi, A; Viazlo, V; Vlasov, N N; Volynets, O; Walczak, R; Abdullah, W A T Wan; Whitmore, J J; Whyte, J; Wiggers, L; Wing, M; Wlasenko, M; Wolf, G; Wolfe, H; Wrona, K; Yagues-Molina, A G; Yamada, S; Yamazaki, Y; Yoshida, R; Youngman, C; Zarnecki, A F; Zawiejski, L; Zenaiev, O; Zeuner, W; Zhautykov, B O; Zhmak, N; Zhou, C; Zichichi, A; Zolko, M; Zotkin, D S; Zulkapli, Z
2010-01-01
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 < y < 0.7, with the requirement of a muon and a jet. Total and differential cross sections are presented and compared to QCD predictions. The beauty contribution to the structure function F_2 was extracted and is compared to theoretical predictions.
Subgraphs in vertex neighborhoods of K-free graphs
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]. © 2004...
Graphs with No Induced Five-Vertex Path or Antipath
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...
Fermion-Boson Vertex at Finite Chemical Potential
ZONG Hong-Shi; FENG Hong-Tao; HOU Feng-Yao; SUN Wei-Min
2007-01-01
Based on the Ward-Takahashi identity at finite chemical potential and Lorentz structure analysis, we generalize the Ball-Chiu vertex to the case of nonzero chemical potential and obtain the general form of the fermionboson vertex in QED at finite chemical potential.
Unquenching the three-gluon vertex: A status report
Blum, Adrian L; Huber, Markus Q; Windisch, Andreas
2015-01-01
We discuss unquenching of the three-gluon vertex via its Dyson-Schwinger equation. We review the role of Furry's theorem and present first results for the quark triangle diagrams using non-perturbatively calculated dressing functions for the quark propagator and the quark-gluon vertex.
The SVX II silicon vertex detector at CDF
Worm, S. [New Mexico Univ., Albuquerque, NM (United States). New Mexico Center for Particle Physics; CDF Collaboration
1996-09-01
The CDF silicon vertex detector is being upgraded for use in Run II of the Fermilab collider. The increased luminosity in Run II, coupled with the desire for increased acceptance and secondary vertex triggering, necessitates a complete redesign of the previous generation tracker. Details of the design are described.
On-shell two-loop three-gluon vertex
Davydychev, A I
1999-01-01
The two-loop three-gluon vertex is calculated in an arbitrary covariant gauge, in the limit when two of the gluons are on the mass shell. The corresponding two-loop results for the ghost-gluon vertex are also obtained. It is shown that the results are consistent with the Ward-Slavnov-Taylor identities.
Genus Ranges of 4-Regular Rigid Vertex Graphs.
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 2n vertices (n > 1), we prove that all intervals [a, b] for all a genus ranges. For graphs with 2n - 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.
Tracking and Vertexing with the ATLAS Inner Detector in the LHC Run2 and Beyond
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, ...
TRACKING AND VERTEXING WITH THE ATLAS INNER DETECTOR IN THE LHC RUN2 AND BEYOND
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, ...
Artificial Spin-Ice and Vertex Models
Cugliandolo, Leticia F.
2017-01-01
In classical and quantum frustrated magnets the interactions in combination with the lattice structure impede the spins to order in optimal configurations at zero temperature. The theoretical interest in their classical realisations has been boosted by the artificial manufacture of materials with these properties, that are of flexible design. This note summarises work on the use of vertex models to study bidimensional spin-ices samples, done in collaboration with R. A. Borzi, M. V. Ferreyra, L. Foini, G. Gonnella, S. A. Grigera, P. Guruciaga, D. Levis, A. Pelizzola and M. Tarzia, in recent years. It is an invited contribution to a J. Stat. Mech. special issue dedicated to the memory of Leo P. Kadanoff.
The Lorentzian proper vertex amplitude: Asymptotics
Engle, Jonathan; Zipfel, Antonia
2015-01-01
In previous work, the Lorentzian proper vertex amplitude for a spin-foam model of quantum gravity was derived. In the present work, the asymptotics of this amplitude are studied in the semi-classical limit. The starting point of the analysis is an expression for the amplitude as an action integral with action differing from that in the EPRL case by an extra `projector' term which scales linearly with spins only in the asymptotic limit. New tools are introduced to generalize stationary phase methods to this case. For the case of boundary data which can be glued to a non-degenerate Lorentzian 4-simplex, the asymptotic limit of the amplitude is shown to equal the single Feynman term, showing that the extra term in the asymptotics of the EPRL amplitude has been eliminated.
Weight Representations of Admissible Affine Vertex Algebras
Arakawa, Tomoyuki; Futorny, Vyacheslav; Ramirez, Luis Enrique
2017-08-01
For an admissible affine vertex algebra {V_k{(\\mathfrak{g})}} of type A, we describe a new family of relaxed highest weight representations of {V_k{(\\mathfrak{g})}}. They are simple quotients of representations of the affine Kac-Moody algebra {\\widehat{\\mathfrak{g}}} induced from the following {\\mathfrak{g}}-modules: (1) generic Gelfand-Tsetlin modules in the principal nilpotent orbit, in particular all such modules induced from {\\mathfrak{sl}_2}; (2) all Gelfand-Tsetlin modules in the principal nilpotent orbit that are induced from {\\mathfrak{sl}_3}; (3) all simple Gelfand-Tsetlin modules over {\\mathfrak{sl}_3}. This in particular gives the classification of all simple positive energy weight representations of {V_k{(\\mathfrak{g})}} with finite dimensional weight spaces for {\\mathfrak{g}=\\mathfrak{sl}_3}.
Vertex Nomination via Content and Context
Coppersmith, Glen A
2012-01-01
If I know of a few persons of interest, how can a combination of human language technology and graph theory help me find other people similarly interesting? If I know of a few people committing a crime, how can I determine their co-conspirators? Given a set of actors deemed interesting, we seek other actors who are similarly interesting. We use a collection of communications encoded as an attributed graph, where vertices represents actors and edges connect pairs of actors that communicate. Attached to each edge is the set of documents wherein that pair of actors communicate, providing content in context - the communication topic in the context of who communicates with whom. In these documents, our identified interesting actors communicate amongst each other and with other actors whose interestingness is unknown. Our objective is to nominate the most likely interesting vertex from all vertices with unknown interestingness. As an illustrative example, the Enron email corpus consists of communications between ac...
The upgrade of the LHCb Vertex Locator
Bird, T
2014-01-01
The LHCb experiment is set for a significant upgrade, which will be ready for Run~3 of the LHC in 2020. This upgrade will allow LHCb to run at a significantly higher instantaneous luminosity and collect an integrated luminosity of $50\\,\\text{fb}^{-1}$ by the end of Run~4. In this process the Vertex locator (VELO) detector will be upgraded to a pixel-based silicon detector. The upgraded VELO will improve upon the current detector by being closer to the beam and having lower material modules with microchannel cooling and a thinner RF-foil. Simulations have shown that it will maintain its excellent performance, even after the radiation damage caused by collecting an integrated luminosity of $50\\,\\text{fb}^{-1}$.
Primary Vertex Reconstruction for Upgrade at LHCb
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.
Deptuch, Grzegorz; Christian, David; Hoff, James; Lipton, Ronald; Shenai, Alpana; Trimpl, Marcel; Yarema, Raymond; Zimmerman, Tom; /Fermilab
2008-12-01
3D-Integrated Circuit technology enables higher densities of electronic circuitry per unit area without the use of nanoscale processes. It is advantageous for mixed mode design with precise analog circuitry because processes with conservative feature sizes typically present lower process dispersions and tolerate higher power supply voltages, resulting in larger separation of a signal from the noise floor. Heterogeneous wafers (different foundries or different process families) may be combined with some 3D integration methods, leading to the optimization of each tier in the 3D stack. Tracking and vertexing in future High-Energy Physics (HEP) experiments involves construction of detectors composed of up to a few billions of channels. Readout electronics must record the position and time of each measurement with the highest achievable precision. This paper reviews a prototype of the first 3D readout chip for HEP, designed for a vertex detector at the International Linear Collider. The prototype features 20 x 20 {micro}m{sup 2} pixels, laid out in an array of 64 x 64 elements and was fabricated in a 3-tier 0.18 {micro}m Fully Depleted SOI CMOS process at MIT-Lincoln Laboratory. The tests showed correct functional operation of the structure. The chip performs a zero-suppressed readout. Successive submissions are planned in a commercial 3D bulk 0.13 {micro}m CMOS process to overcome some of the disadvantages of an FDSOI process.
TGV32: A 32-channel preamplifier chip for the multiplicity vertex detector at PHENIX
Britton, C.L. Jr.; Ericson, M.N.; Frank, S.S. [and others
1997-12-31
The TGV32, a 32-channel preamplifier-multiplicity discriminator chip for the Multiplicity Vertex Detector (MVD) at PHENIX, is a unique silicon preamplifier in that it provides both an analog output for storage in an analog memory and a weighted summed-current output for conversion to a channel multiplicity count. The architecture and test results of the chip are presented. Details about the design of the preamplifier, discriminator, and programmable digital-analog converters (DACs) performance as well as the process variations are presented. The chip is fabricated in a 1.2-{micro}m, n-well, CMOS process.
Development of Single- and Double-sided Ladders for the ILD Vertex Detectors
Baudot, Jerome; Chon-Sen, Nathalie; Dulinski, Wojciech; Hegner, Franziska; Gelin-Galibel, Marie; Gauld, Rhorry; Goffe, Mathieu; Goldstein, Joel; Gregor, Ingrid; Hu-Guo, Christine; Koetz, Ulrich; Nomerotski, Andrei; Winter, Marc
2012-01-01
We discuss two projects exploring the integration of thin CMOS pixel sensors in order to prototype ladders matching the geometry needed for the ILD vertex detector. The PLUME project has designed and fabricated full-size and fully functional double- sided layers which currently reach 0.6 % X0 and aim for 0.3 % X0 in mid-2012. Another approach, SERNWIETE, consists in wrapping the sensors in a polyimide-based micro-cable to obtain a supportless single-sided ladder with a material budget around 0.15 % X0. First promising samples have been produced and the full-size prototype is expected in spring 2012.
Locking mechanisms in degree-4 vertex origami structures
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.
Measurement of $R_{b}$ using a Vertex Mass Tag
Abe, K; Akagi, T; Allen, N J; Ash, W W; Aston, D; Baird, K G; Baltay, C; Band, H R; Barakat, M B; Baranko, G; Bardon, O; Barklow, T L; Bashindzhagian, G L; Bazarko, A O; Ben-David, R; Benvenuti, Alberto C; Bilei, G M; Bisello, D; Blaylock, G; Bogart, J R; Bolen, B; Bolton, T; Bower, G R; Brau, J E; Breidenbach, M; Bugg, W M; Burke, D; Burnett, T H; Burrows, P N; Busza, W; Calcaterra, A; Caldwell, D O; Calloway, D; Camanzi, B; Carpinelli, M; Cassell, R; Castaldi, R; Castro, A; Cavalli-Sforza, M; Chou, A; Church, E; Cohn, H O; Coller, J A; Cook, V; Cotton, R; Cowan, R F; Coyne, D G; Crawford, G; de Oliveira, A; Damerell, C J S; Daoudi, M; De Groot, N; De Sangro, R; Dell'Orso, R; Dervan, P J; Dima, M; Dong, D N; Du, P Y C; Dubois, R; Eisenstein, B I; Elia, R; Etzion, E; Fahey, S; Falciai, D; Fan, C; Fernández, J P; Fero, M J; Frey, R; Gillman, T; Gladding, G; González, S; Hart, E L; Harton, J L; Hasan, A; Hasegawa, Y; Hasuko, K; Hedges, S J; Hertzbach, S S; Hildreth, M D; Huber, J; Huffer, M E; Hughes, E W; Hwang, H; Iwasaki, Y; Jackson, D J; Jacques, P; Jaros, J A; Jiang, Z Y; Johnson, A S; Johnson, J R; Johnson, R A; Junk, T R; Kajikawa, R; Kalelkar, M; Kang, H J; Karliner, I; Kawahara, H; Kendall, H W; Kim, Y D; King, M E; King, R; Kofler, R R; Krishna, N M; Kroeger, R S; Labs, J F; Langston, M; Lath, A; Lauber, J A; Leith, D W G S; Lia, V; Liu, M X; Liu, X; Loreti, M; Lu, A; Lynch, H L; Ma, J; Mancinelli, G; Manly, S; Mantovani, G C; Markiewicz, T W; Maruyama, T; Masuda, H; Mazzucato, E; McKemey, A K; Meadows, B T; Messner, R; Mockett, P M; Moffeit, K C; Moore, T B; Müller, D; Nagamine, T; Narita, S; Nauenberg, U; Neal, H; Nussbaum, M; Ohnishi, Y; Oishi, N; Onoprienko, D; Osborne, L S; Panvini, R S; Park, C H; Park, H; Pavel, T J; Peruzzi, I; Piccolo, M; Piemontese, L; Pieroni, E; Pitts, K T; Plano, R J; Prepost, R; Prescott, C Y; Punkar, G D; Quigley, J; Ratcliff, B N; Reeves, T W; Reidy, J; Reinertsen, P L; Rensing, P E; Rochester, L S; Rowson, P C; Russell, J J; Saxton, O H; Schalk, T; Schindler, R H; Schumm, B A; Schwiening, J; Sen, S; Serbo, V V; Shaevitz, M H; Shank, J T; Shapiro, G; Sherden, D J; Shmakov, K D; Simopoulos, C; Sinev, N B; Smith, S R; Smy, M B; Snyder, J A; Stängle, H; Stamer, P; Steiner, H; Steiner, R; Strauss, M G; Su, D; Suekane, F; Sugiyama, A; Suzuki, S; Swartz, M; Szumilo, A; Takahashi, T; Taylor, F E; Torrence, E; Trandafir, A I; Turk, J D; Usher, T; Vavra, J; Vannini, C; Vella, E; Venuti, J P; Verdier, R; Verdini, P G; Wagner, D L; Wagner, S R; Waite, A P; Watts, S J; Weidemann, A W; Weiss, E R; Whitaker, J S; White, S L; Wickens, F J; Williams, D C; Williams, S H; Willocq, S; Wilson, R J; Wisniewski, W J; Woods, M; Word, G B; Wyss, J; Yamamoto, R K; Yamartino, J M; Yang, X; Yashima, J; Yellin, S J; Young, C C; Yuta, H; Zapalac, G; Zdarko, R W; Zhou, J
1998-01-01
We report a new measurement of Rb = Gamma(Z0->b-bbar) / Gamma(Z0->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 130k hadronic Z0 events, collected with the SLD at the SLC. The method utilizes the 3-D 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 Rb=0.2142+/-0.0034(stat.)+/-0.0015(syst.)+/-0.0002(R_c).
Quark-gluon vertex in arbitrary gauge and dimension
Davydychev, A I; Saks, L
2001-01-01
One-loop off-shell contributions to the quark-gluon vertex are calculated, in an arbitrary covariant gauge and in arbitrary space-time dimension, including quark-mass effects. It is shown how one can get results for all on-shell limits of interest directly from the off-shell expressions. In order to demonstrate that the Ward-Slavnov-Taylor identity for the quark-gluon vertex is satisfied, we have also calculated the corresponding one-loop contribution involving the quark-quark-ghost-ghost vertex.
Animation Visualization for Vertex Coloring of Polyhedral Graphs
Hidetoshi Nonaka
2013-12-01
Full Text Available Vertex coloring of a graph is the assignment of labels to the vertices of the graph so that adjacent vertices have different labels. In the case of polyhedral graphs, the chromatic number is 2, 3, or 4. Edge coloring problem and face coloring problem can be converted to vertex coloring problem for appropriate polyhedral graphs. We have been developed an interactive learning system of polyhedra, based on graph operations and simulated elasticity potential method, mainly for educational purpose. In this paper, we introduce a learning subsystem of vertex coloring, edge coloring and face coloring, based on minimum spanning tree and degenerated polyhedron, which is introduced in this paper.
Performance of the LHCb Vertex Locator
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 ...
The PHENIX Forward Silicon Vertex Detector
Aidala, C; Anderssen, LE; Bambaugh, A; Barron, A; Boissevain, J G; Bok, J; Boose, S; Brooks, M L; Butsyk, S; Cepeda, LM; Chacon, P; Chacon, S; Chavez, L; Cote, T; D'Agostino, C; Datta, A; DeBlasio, K; DelMonte, L; Desmond, E J; Durham, J M; Fields, D; Finger, M; Gingu, C; Gonzales, B; Haggerty, J S; Hawke, T; van Hecke, H W; Herron, M; Hoff, J; Huang, J; Jiang, X; Johnson, LT; Jonas, M; Kapustinsky, J; Key, A; Kunde, G J; LaBounty, J; Lee, D M; Lee, K B; Leitch, M J; Lenz, M; Lenz, W; Liu, M X; Lynch, D; Mannel, E; McGaughey, P L; Meles, A; Meredith, B; Nguyen, H; O'Brien, E; Pak, R; Papavassiliou, V; Pate, S; Pereira, H; Perera, G D N; Phillips, M; Pisani, R; Polizzo, S; Poncione, R J; Popule, J; Prokop, M; Purschke, M L; Purwar, A K; Ronzhina, N; Silva, C L; Slunecka, M; Smith, R; Sondheim, W E; Spendier, K; Stoffer, M; Tennant, E; Thomas, D; Tomasek, M; Veicht, A; Vrba, V; Wang, X R; Wei, F; Winter, D; Yarema, R; You, Z; Zimmerman, A; Zimmerman, T
2013-01-01
A new silicon detector has been developed to provide the PHENIX experiment with precise charged particle tracking at forward and backward rapidity. The Forward Silicon Vertex Tracker (FVTX) was installed in PHENIX prior to the 2012 run period of the Relativistic Heavy Ion Collider (RHIC). The FVTX is composed of two annular endcaps, each with four stations of silicon mini-strip sensors, covering a rapidity range of $1.2<|\\eta|<2.2$ that closely matches the two existing PHENIX muon arms. Each station consists of 48 individual silicon sensors, each of which contains two columns of mini-strips with 75 $\\mu$m pitch in the radial direction and lengths in the $\\phi$ direction varying from 3.4 mm at the inner radius to 11.5 mm at the outer radius. The FVTX has approximately 0.54 million strips in each endcap. These are read out with FPHX chips, developed in collaboration with Fermilab, which are wire bonded directly to the mini-strips. The maximum strip occupancy reached in central Au-Au collisions is approxim...
Vertex micromagnetic energy in artificial square ice
Perrin, Yann; Canals, Benjamin; Rougemaille, Nicolas
2016-10-01
Artificial arrays of interacting magnetic elements provide an uncharted arena in which the physics of magnetic frustration and magnetic monopoles can be observed in real space and in real time. These systems offer the formidable opportunity to investigate a wide range of collective magnetic phenomena with a lab-on-chip approach and to explore various theoretical predictions from spin models. Here, we study artificial square ice systems numerically and use micromagnetic simulations to understand how the geometrical parameters of the individual magnetic elements affect the energy levels of an isolated square vertex. More specifically, we address the question of whether the celebrated square ice model could be made relevant for artificial square ice systems. Our work reveals that tuning the geometry alone should not allow the experimental realization of the square ice model when using nanomagnets coupled through the magnetostatic interaction. However, low-aspect ratios combined with small gaps separating neighboring magnetic elements of moderated thickness might permit approaching the ideal case where the degeneracy of the ice rule states is recovered.
Radiation damage in the LHCb Vertex Locator
Affolder, A; Alexander, M; Ali, S; Artuso, M; Benton, J; van Beuzekom, M; Bjørnstad, P M; Bogdanova, G; Borghi, S; Bowcock, T J V; Brown, H; Buytaert, J; Casse, G; Collins, P; De Capua, S; Dossett, D; Eklund, L; Farinelli, C; Garofoli, J; Gersabeck, M; Gershon, T; Gordon, H; Harrison, J; Heijne, V; Hennessy, K; Hutchcroft, D; Jans, E; John, M; Ketel, T; Lafferty, G; Latham, T; Leflat, A; Liles, M; Moran, D; Mous, I; Oblakowska-Mucha, A; Parkes, C; Patel, G D; Redford, S; Reid, M M; Rinnert, K; Rodrigues, E; Schiller, M; Szumlak, T; Thomas, C; Velthuis, J; Volkov, V; Webber, A D; Whitehead, M; Zverev, E
2013-01-01
The LHCb Vertex Locator (VELO) is a silicon strip detector designed to reconstruct charged particle trajectories and vertices produced at the LHCb interaction region. During the first two years of data collection, the 84 VELO sensors have been exposed to a range of fluences up to a maximum value of approximately $\\rm{45 \\times 10^{12}\\,1\\,MeV}$ neutron equivalent ($\\rm{1\\,MeV\\,n_{eq}}$). At the operational sensor temperature of approximately $-7\\,^{\\circ}\\rm{C}$, the average rate of sensor current increase is 18$\\mu$ A per $\\rm{fb^{-1}}$, in excellent agreement with predictions. The silicon effective bandgap has been determined using current versus temperature scan data after irradiation, with an average value of $E_{g}=1.16\\pm0.03\\pm0.04\\,\\rm{eV}$ obtained. The first observation of n-on-n sensor type inversion at the LHC has been made, occurring at a fluence of around $15 \\times 10 ^{12}$ of $1\\,\\rm{MeV\\,n_{eq}}$. The only n-on-p sensors in use at the LHC have also been studied. With an initial fluence of ap...
Torus Knots and the Topological Vertex
Jockers, Hans; Soroush, Masoud
2012-01-01
We propose a class of toric Lagrangian A-branes on the resolved conifold that is suitable to describe torus knots on S^3. The key role is played by the SL(2,Z) transformation, which generates a general torus knot from the unknot. Applying the topological vertex to the proposed A-branes, we rederive the colored HOMFLY polynomials for torus knots, in agreement with the Rosso and Jones formula. We show that our A-model construction is mirror symmetric to the B-model analysis of Brini, Eynard and Marino. Comparing to the recent proposal by Aganagic and Vafa for knots on S^3, we demonstrate that the disk amplitude of the A-brane associated to any knot is sufficient to reconstruct the entire B-model spectral curve. Finally, the construction of toric Lagrangian A-branes is generalized to other local toric Calabi-Yau geometries, which paves the road to study knots in other three-manifolds such as lens spaces.
Status of the LHCb VErtex LOcator
Palacios, J P
2003-01-01
LHCb is a single arm spectrometer at the LHC. It is dedicated to the study of CP violation in the B-hadron system. The VErtex LOcator (VELO) is a silicon microstrip detector providing accurate measurements of event primary and secondary vertices, impact parameters, and tracks. The second level trigger decision of LHCb is mainly based on information from a full readout of the VELO. This document gives a general introduction to LHCb as a context for a more extensive description of the VELO. The VELO design emphasises the need for precise reconstruction of tracks down to momenta of a few GeV. The VELO operates inside the LHC beam-pipe, and the sensors, the hybrids, and the foil separating the primary and secondary vacuua must be built with the minimum possible material. The R-$\\phi$ strip layout is optimised for efficient trigger operation and precise measurements at the smallest radii. The performance must be maintained in the harsh radiation environment close to the LHC beams. These issues have led to a choice...
Dynamical Vertex Approximation for the Hubbard Model
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.
Long-term studies of the optical components in the ZEUS calorimeter using a moving 60Co source
Bohnet, I.; Feller, R.-P.; Krumnack, N.; Möller, E.; Prause, H.; Salehi, H.; Wick, K.
2009-02-01
The response of the ZEUS sampling calorimeter has been studied over a period of 17 years using a moving 60Co source. The aim was to monitor the stability of the calorimeter with respect to radiation damage, ageing and mechanical damage. The measurements started in 1990 during the installation of the first calorimeter modules and ended in 2007 after the last HERA run. Within the experimental uncertainties, the longitudinal uniformity of the polymethylmethacrylate (PMMA) based wavelength shifters (Y7) did not change. There is also no evidence for radiation damage in the polystyrene (PS) based scintillators (SCSN-38) due to particle losses of the electron and proton beams. On the other hand, the investigations clearly indicate that the attenuation length of the SCSN-38 scintillators decreased continuously over the years. A comparison with data obtained from a test calorimeter showed that the same effect observed in the ZEUS calorimeter after 17 years would require a uniform exposure of all scintillators by a dose of (2.8±1) kGy of γ rays. However, it can be excluded that the degradation observed in the ZEUS calorimeter can be attributed to the radioactivity of the uranium plates of the calorimeter. Thus we expect that the decrease of the attenuation length is due to ageing of the scintillators. The ageing effects observed in SCSN-38 are compared to data taken from the literature.
LHCb: Performance and Radiation Damage Effects in the LHCb Vertex Locator
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 ...
On vertex-coloring edge-weighting of graphs
Honglian LU; Xu YANG; Qinglin YU
2009-01-01
A k-edge-weighting w of a graph G is an assignment of an integer weight, w(e) ∈ {1,..., k}, to each edge e. An edge-weighting naturally induces a vertex coloring c by defining e(u) = ∑eЭuw(e) for every u ∈ V(G). A k-edge-weighting of a graph G is vertex-coloring if the induced coloring c is proper, I.e., c(u)≠c(v) for any edge uv ∈ E(G). When k ≡ 2 (mod 4)and k≥ 6, we prove that if G is k-colorable and 2-connected, δ(G) ≥ k - 1, then G admits a vertex-coloring k-edge-weighting. We also obtain several sufficient conditions for graphs to be vertex-coloring k-edge-weighting.
The $\\omega DD$ vertex in a Sum Rule approach
Holanda, L B; Mihara, A
2007-01-01
The study of charmonium dissociation in heavy ion collisions is generally performed in the framework of effective Lagrangians with meson exchange. Some studies are also developed with the intention of calculate form factors and coupling constants related with charmed and light mesons. These quantities are important in the evaluation of charmonium cross sections. In this paper we present a calculation of the $\\omega DD$ vertex that is a possible interaction vertex in some meson-exchange models spread in the literature. We used the standard method of QCD Sum Rules in order to obtain the vertex form factor as a function of the transferred momentum. Our results are compatible with the value of this vertex form factor (at zero momentum transfer) obtained in the vector-meson dominance model.
A new method for counting trees with vertex partition
2008-01-01
A direct and elementary method is provided in this paper for counting trees with vertex partition instead of recursion, generating function, functional equation, Lagrange inversion, and matrix methods used before.
Assembling the last module of the vertex locator for LHCb
Maximilien Brice
2007-01-01
The 42nd and final vertex locator module is assembled in the LHCb clean room. This will be used to measure the point at which two protons in the beam collide from the tracks of particles produced in the collision.
Vertex models: from cell mechanics to tissue morphogenesis
Alt, Silvanus; Ganguly, Poulami
2017-01-01
Tissue morphogenesis requires the collective, coordinated motion and deformation of a large number of cells. Vertex model simulations for tissue mechanics have been developed to bridge the scales between force generation at the cellular level and tissue deformation and flows. We review here various formulations of vertex models that have been proposed for describing tissues in two and three dimensions. We discuss a generic formulation using a virtual work differential, and we review applications of vertex models to biological morphogenetic processes. We also highlight recent efforts to obtain continuum theories of tissue mechanics, which are effective, coarse-grained descriptions of vertex models. This article is part of the themed issue ‘Systems morphodynamics: understanding the development of tissue hardware’. PMID:28348254
Factorial Schur functions via the six vertex model
McNamara, Peter J
2009-01-01
For a particular set of Boltzmann weights and a particular boundary condition for the six vertex model in statistical mechanics, we compute explicitly the partition function and show it to be equal to a factorial Schur function.
Vertex Reconstruction in the ATLAS Experiment at the LHC
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.
Mirror of the refined topological vertex from a matrix model
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.
The vertex detector for the Lepton/Photon collaboration
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.
R&D Challenges of a CLIC Vertex Detector
van der Kraaij, E
2010-01-01
The Compact Linear Collider (CLIC) is a concept for an electron-positron collider with a center- of-mass energy of up to 3 TeV. Given the unprecedented experimental conditions at CLIC none of the technologies available today can fulfill all requirements set for the vertex detector. At the conference these conditions and the challenges they pose for the R&D of a CLIC vertex detector were presented.
The vertex detector for the Lepton/Photon collaboration
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.
Performance of the ATLAS primary vertex reconstruction algorithms
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.
DISTRIBUTED VERTEX COVER ALGORITHMS FOR WIRELESS SENSOR NETWORKS
Vedat Kavalci
2014-01-01
Full Text Available Vertex covering has important applications for wireless sensor networks such as monitoring link failures, facility location, clustering, and data aggregation. In this study, we designed three algorithms for constructing vertex cover in wireless sensor networks. The first algorithm, which is an adaption of the Parnas & Ron’s algorithm, is a greedy approach that finds a vertex cover by using the degrees of the nodes. The second algorithm finds a vertex cover from graph matching where Hoepman’s weighted matching algorithm is used. The third algorithm firstly forms a breadth-first search tree and then constructs a vertex cover by selecting nodes with predefined levels from breadth-first tree. We show the operation of the designed algorithms, analyze them, and provide the simulation results in the TOSSIM environment. Finally we have implemented, compared and assessed all these approaches. The transmitted message count of the first algorithm is smallest among other algorithms where the third algorithm has turned out to be presenting the best results in vertex cover approximation ratio.
Measurements of the exclusive production of a real photon with the ZEUS detector at HERA II
Santamarta Martinez, R.
2007-06-15
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{sup -1} for e{sup +}p and 136 pb{sup -1} for e{sup -}p scattering data. The cross section of the elastic Bethe-Heitler process measured in the kinematic region 230 < < W < 310 GeV, 20
Study of deep inelastic inclusive and diffractive scattering with the ZEUS forward plug calorimeter
Abramowicz, H; Adamczyk, L; Adamus, M; Adler, V; Aghuzumtsyan, G; Allfrey, P D; Antonioli, P; Antonov, A; Arneodo, M; Bailey, D S; Bamberger, A; Barakbaev, A N; Barbagli, G; Barbi, M; Bari, G; Barreiro, F; Bartsch, D; Basile, M; Behrens, U; Bell, M A; Bellagamba, L; Bellan, P M; Benen, A; Bertolin, A; Bhadra, S; Bloch, I; Bold, T; Boos, E G; Borras, K; Boscherini, D; Brock, I; Brook, N H; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Bussey, P J; Butterworth, J M; Büttner, C; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carli, T; Carlin, R; Cassel, D G; Catterall, C D; Chekanov, S; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, Luisa; Cindolo, F; Cole, J E; Collins-Tooth, C; Contin, A; Cooper-Sarkar, A M; Coppola, N; Corradi, M; Corriveau, F; Costa, M; Cottrell, A; Cui, Y; D'Agostini, G; Dal Corso, F; Danilov, P; De Pasquale, S; Dementiev, R K; Derrick, M; Devenish, R C E; Dhawan, S; Dobur, D; Dolgoshein, B A; Doyle, A T; Drews, G; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, Andrzej; Everett, A; Ferrando, J; Ferrero, M I; Figiel, J; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fry, C; Gabareen, A; Galas, A; Gallo, E; Garfagnini, A; Geiser, A; Genta, C; Gialas, I; Giusti, P; Gladilin, L K; Gladkov, D; Glasman, C; Göbel, F; Goers, S; Goncalo, R; González, O; Gosau, T; Göttlicher, P; Grabowska-Bold, I; Graciani-Díaz, R; Grigorescu, G; Grijpink, S; Groys, M; Grzelak, G; Gutsche, O; Gwenlan, C; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hamilton, J; Hanlon, S; Hart, C; Hartmann, H; Hartner, G; Heaphy, E A; Heath, G P; Helbich, M; Hilger, E; Hochman, D; Holm, U; Horn, C; Iacobucci, G; Iga, Y; Irrgang, P; Jakob, H P; Jiménez, M; Jones, T W; Kagawa, S; Kahle, B; Kaji, H; Kananov, S; Karshon, U; Karstens, F; Kasemann, M; Kataoka, M; Katkov, I I; Kcira, D; Keramidas, A; Khein, L A; Kim, J Y; Kind, O; Kisielewska, D; Kitamura, S; Koffeman, E; Kohno, T; Kooijman, P; Koop, T; Korzhavina, I A; Kotanski, A; Kötz, U; Kowal, A M; Kowalski, H; Kramberger, G; Kreisel, A; Krumnack, N; Kulinski, P; Kuze, M; Kuzmin, V A; Labarga, L; Lammers, S; Lelas, D; Levchenko, B B; Levy, A; Li, L; Lightwood, M S; Lim, H; Limentani, S; Ling, T Y; Liu, C; Liu, X; Löhr, B; Lohrmann, E; Loizides, J H; Long, K R; Longhin, A; Lukasik, J; Lukina, O Yu; Luzniak, P; Ma, K J; Maddox, E; Magill, S; Malka, J; Mankel, R; Margotti, A; Marini, G; Martin, J F; Martínez, M; Mastroberardino, A; Matsuzawa, K; Mattingly, M C K; Melzer-Pellmann, I A; Menary, S R; Metlica, F; Meyer, U; Miglioranzi, S; Milite, M; Mirea, A; Monaco, V; Montanari, A; Musgrave, B; Nagano, K; Namsoo, T; Nania, R; Nguyen, C N; Nigro, A; Ning, Y; Noor, U; Notz, D; Nowak, R J; Nuncio-Quiroz, A E; Oh, B Y; Olkiewicz, K; Ota, O; Padhi, S; Palmonari, F; Patel, S; Paul, E; Pavel, Usan; Pawlak, J M; Pelfer, P G; Pellegrino, A; Pesci, A; Piotrzkowski, K; Plamondon, M; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Proskuryakov, A S; Przybycien, M B; Rautenberg, J; Raval, A; Reeder, D D; Ren, Z; Renner, R; Repond, J; Ri, Y D; Rinaldi, L; Robins, S; Rosin, M; Ruspa, M; Ryan, P; Sacchi, R; Salehi, H; Santamarta, R; Sartorelli, G; Savin, A A; Saxon, D H; Schagen, S; Schioppa, M; Schlenstedt, S; Schleper, P; Schmidke, W B; Schneekloth, U; Schörner-Sadenius, T; Sciulli, F; Shcheglova, L M; Skillicorn, I O; Slominski, W; Smith, W H; Soares, M; Solano, A; Son, D; Sosnovtsev, V V; Stairs, D G; Stanco, L; Standage, J; Stifutkin, A; Stonjek, S; Stopa, P; Stösslein, U; Straub, P B; Suchkov, S; Susinno, G; Suszycki, L; Sutiak, J; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tapper, A D; Targett-Adams, C; Tassi, E; Tawara, T; Terron, J; Tiecke, H G; Tokushuku, K; Tsurugai, T; Turcato, M; Tymieniecka, T; Tyszkiewicz, A; Ukleja, A; Ukleja, J; Vázquez, M; Vlasov, N N; Voss, K C; Walczak, R; Walsh, R; Wang, M; Whitmore, J J; Whyte, J; Wichmann, K; Wick, K; Wiggers, L; Wills, H H; Wing, M; Wlasenko, M; Wolf, G; Yagues-Molina, A G; Yamada, S; Yamazaki, Y; Yoshida, R; Youngman, C; Zambrana, M; Zawiejski, L; Zeuner, W; Zhautykov, B O; Zhou, C; Zichichi, A; Ziegler, A; Zotkin, D S; Zotkin, S A; De Favereau, J; De Wolf, E; Del Peso, J
2005-01-01
Deep inelastic scattering and its diffractive component, ep -> e'gamma*p ->e'XN, have been studied at HERA with the ZEUS detector using an integrated luminosity of 4.2 pb-1. The measurement covers a wide range in the gamma*p c.m. energy W (37 - 245 GeV), photon virtuality Q2 (2.2 - 80 GeV2) and mass Mx. The diffractive cross section for Mx > 2 GeV rises strongly with W; the rise is steeper with increasing Q2. The latter observation excludes the description of diffractive deep inelastic scattering in terms of the exchange of a single Pomeron. The ratio of diffractive to total cross section is constant as a function of W, in contradiction to the expectation of Regge phenomenology combined with a naive extension of the optical theorem to gamma*p scattering. Above Mx of 8 GeV, the ratio is flat with Q2, indicating a leading-twist behaviour of the diffractive cross section. The data are also presented in terms of the diffractive structure function, F2D(3)(beta,xpom,Q2), of the proton. For fixed beta, the Q2 depend...
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
Childers, Annie Burns; Vidakovic, Draga
2014-01-01
This paper explores sixty-six students' personal meaning and interpretation of the vertex of a quadratic function in relation to their understanding of quadratic functions in two different representations, algebraic and word problem. Several categories emerged from students' personal meaning of the vertex including vertex as maximum or minimum…
VERTEX: manganese transport through oxygen minima
Martin, John H.; Knauer, George A.
1984-01-01
Manganese transport through a well-developed oxygen minimum was studied off central Mexico (18°N, 108°W) in October-November 1981 as part of the VERTEX (Vertical Transport and Exchange) research program. Refractory, leachable and dissolved Mn fractions associated with particulates caught in traps set at eight depths (120-1950 m) were analyzed. Particles entering the oxygen minimum had relatively large Mn loads; however, as the particulates sank further into the minimum, total Mn fluxes steadily decreased from 190 nmol m -2 day -1 at 120 m to 36 nmol m -2 day -1 at 400 m. Manganese fluxes then steadily increased in the remaining 800-1950 m, reaching rates of up to 230 nmol m -2 day -1 at 1950 m. Manganese concentrations were also measured in the water column. Dissolved Mn levels Rate-of-change estimates based on trap flux data yield regeneration rates of up to 0.44 nmol kg -1 yr -1 in the upper oxygen minimum (120-200 m). However, only 30% of the dissolved Mn in the oxygen minimum appears to be from sinking particulate regeneration; the other 70% probably results from continental-slope-release-horizontal-transport processes. Dissolved Mn scavenges back onto particles as oxygen levels begin to increase with depth. Scavenging rates ranging from -0.03 to -0.09 nmol kg -1 yr -1 were observed at depths from 700 to 1950 m. These scavenging rates result in Mn residence times of 16-19 years, and scavenging rate constants on the order of 0.057 yr -1. Manganese removal via scavenging on sinking particles below the oxygen minimum is balanced by Mn released along continental boundaries and transported horizontally via advective-diffusive processes. Manganese appears to be very weakly associated with particulates. Nevertheless, the amounts of Mn involved with sinking biogenic particles are large, and the resulting fluxes are on the same order of magnitude as those necessary to explain the excess Mn accumulating on the sea floor. The overall behavior of Mn observed in this, and
A covariant representation of the Ball–Chiu vertex
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.
Directed Subset Feedback Vertex Set is Fixed-Parameter Tractable
Chitnis, Rajesh; Hajiaghayi, MohammadTaghi; Marx, Dániel
2012-01-01
Given a graph $G$ and an integer $k$, the \\textsc{Feedback Vertex Set} (\\textsc{FVS}) problem asks if there is a vertex set $T$ of size at most $k$ that hits all cycles in the graph. Bodlaender (WG '91) gave the first fixed-parameter algorithm for \\textsc{FVS} in undirected graphs. The fixed-parameter tractability status of \\textsc{FVS} in directed graphs was a long-standing open problem until Chen et al. (STOC '08) showed that it is fixed-parameter tractable by giving an $4^{k}k!n^{O(1)}$ algorithm. In the subset versions of this problems, we are given an additional subset $S$ of vertices (resp. edges) and we want to hit all cycles passing through a vertex of $S$ (resp. an edge of $S$). Indeed both the edge and vertex versions are known to be equivalent in the parameterized sense. Recently the \\textsc{Subset Feedback Vertex Set} in undirected graphs was shown to be FPT by Cygan et al. (ICALP '11) and Kakimura et al. (SODA '12). We generalize the result of Chen et al. (STOC '08) by showing that \\textsc{Subset...
Hessian and graviton propagator of the proper vertex
Shirazi, Atousa Chaharsough; Vilensky, Ilya
2015-01-01
The proper spin-foam vertex amplitude is obtained from the EPRL vertex by projecting out all but a single gravitational sector, in order to achieve correct semi-classical behavior. In this paper we calculate the gravitational two-point function predicted by the proper spin-foam vertex to lowest order in the vertex expansion. We find the same answer as in the EPRL case in the `continuum spectrum' limit, so that the theory is consistent with the predictions of linearized gravity in the regime of small curvature. The method for calculating the two-point function is similar to that used in prior works: we cast it in terms of an action integral and to use stationary phase methods. Thus, the calculation of the Hessian matrix plays a key role. Once the Hessian is calculated, it is used not only to calculate the two-point function, but also to calculate the coefficient appearing in the semi-classical limit of the proper vertex amplitude itself. This coefficient is the effective discrete "measure factor" encoded in th...
On trees with total domination number equal to edge-vertex domination number plus one
B Krishnakumari; Y B Venkatakrishnan; Marcin Krzywkowski
2016-05-01
An edge $e \\in E(G)$ dominates a vertex $v \\in V(G)$ if $e$ is incident with $v$ or $e$ is incident with a vertex adjacent to $v$. An edge-vertex dominating set of a graph $G$ is a set $D$ of edges of $G$ such that every vertex of $G$ is edge-vertex dominated by an edge of $D$. The edge-vertex domination number of a graph $G$ is the minimum cardinality of an edge-vertex dominating set of $G$. A subset $D \\subseteq V(G)$ is a total dominating set of $G$ if every vertex of $G$ has a neighbor in $D$. The total domination number of $G$ is the minimum cardinality of a total dominating set of $G$. We characterize all trees with total domination number equal to edge-vertex domination number plus one.
On the uniqueness of d-vertex magic constant
Arumugam S.
2014-05-01
Full Text Available Let G = (V,E be a graph of order n and let D ⊆ {0, 1, 2, 3, . . .}. For v ∈ V, let ND(v = {u ∈ V : d(u, v ∈ D}. The graph G is said to be D-vertex magic if there exists a bijection f : V (G → {1, 2, . . . , n} such that for all v ∈ V, ∑uv∈ND(v f(u is a constant, called D-vertex magic constant. O’Neal and Slater have proved the uniqueness of the D-vertex magic constant by showing that it can be determined by the D-neighborhood fractional domination number of the graph. In this paper we give a simple and elegant proof of this result. Using this result, we investigate the existence of distance magic labelings of complete r-partite graphs where r ≥ 4.
Plethystic Vertex Operators and Boson-Fermion Correspondences
Fauser, Bertfried; King, Ronald C
2016-01-01
We study the algebraic properties of plethystic vertex operators, introduced in J. Phys. A: Math. Theor. 43 405202 (2010), 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 \\pi. Here we establish an extension of the well-known boson-fermion correspondence involving Schur functions and their associated (Bernstein) vertex operators: for each \\pi, 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.
Plethystic vertex operators and boson-fermion correspondences
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.
Fatigue crack shape prediction based on vertex singularity
Hutař P.
2008-11-01
Full Text Available Due to the existence of vertex singularity at the point where the crack intersects the free surface, stress distribution around the crack tip and the type of the singularity is changed. In the interior of the specimen the classical singular behaviour of the crack is dominant and can be described using analytic equations. Contrary to this, at the free surface or in the boundary layer close to free surface the vertex singularity is significant. The influence of vertex singularity on crack behaviour and a crack shape for a three-dimensional structure is described in this paper. The results presented make it possible to estimate fatigue crack growth rate and crack shape using the concept of the generalized stress intensity factor. The estimated fatigue crack shape can help to provide a more reliable estimation of the fatigue life of the structures considered.
Vertex-centred Method to Detect Communities in Evolving Networks
Canu, Maël; d'Allonnes, Adrien Revault
2016-01-01
Finding communities in evolving networks is a difficult task and raises issues different from the classic static detection case. We introduce an approach based on the recent vertex-centred paradigm. The proposed algorithm, named DynLOCNeSs, detects communities by scanning and evaluating each vertex neighbourhood, which can be done independently in a parallel way. It is done by means of a preference measure, using these preferences to handle community changes. We also introduce a new vertex neighbourhood preference measure, CWCN, more efficient than current existing ones in the considered context. Experimental results show the relevance of this measure and the ability of the proposed approach to detect classical community evolution patterns such as grow-shrink and merge-split.
Performance, Radiation Damage Effects and Upgrade of the LHCb Vertex Locator
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...
Semiclassical correlation functions of Wilson loops and local vertex operators
Hernandez, Rafael
2012-01-01
We analyze correlation functions of Wilson loop observables and local vertex operators within the strong-coupling regime of the AdS/CFT correspondence. When the local operator corresponds to a light string state with finite conserved charges the correlation function can be evaluated in the semiclassical approximation of large string tension, where the contribution from the light vertex can be neglected. We consider the cases where the Wilson loops are described by two concentric surfaces and the local vertices are the superconformal chiral primary scalar or a singlet massive scalar operator.
Simulations of silicon vertex tracker for star experiment at RHIC
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.
The RAVE/VERTIGO vertex reconstruction toolkit and framework
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.
RAVE-a Detector-independent vertex reconstruction toolkit
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.
The RAVE/VERTIGO vertex reconstruction toolkit and framework
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.
Simulations of silicon vertex tracker for star experiment at RHIC
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.
On vertex-coloring 13-edge-weighting
Tao WANG; Qinglin YU
2008-01-01
L. Addario-Berry et al. [Discrete Appl. Math., 2008, 156:1168-1174] have shown that there exists a 16-edge-weighting such that the induced vertex coloring is proper. In this note, we improve their result and prove that there exists a 13-edge-weighting of a graph G, such that itsinduced vertex coloring of G is proper. This result is one step close to the original conjecture posed by M. Karofiski et al. [J. Combin. Theory, Set. B, 2004, 91: 151-157].
Preliminary studies for the LHCb vertex detector vacuum system
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.
The Virasoro vertex algebra and factorization algebras on Riemann surfaces
Williams, Brian
2017-08-01
This paper focuses on the connection of holomorphic two-dimensional factorization algebras and vertex algebras which has been made precise in the forthcoming book of Costello-Gwilliam. We provide a construction of the Virasoro vertex algebra starting from a local Lie algebra on the complex plane. Moreover, we discuss an extension of this factorization algebra to a factorization algebra on the category of Riemann surfaces. The factorization homology of this factorization algebra is computed as the correlation functions. We provide an example of how the Virasoro factorization algebra implements conformal symmetry of the beta-gamma system using the method of effective BV quantization.
Dannheim, D
2014-01-01
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 current status of R&D on sensors, readout and detector integration is presented.
Dannheim, D
2014-01-01
A detector concept based on hybrid 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 (planar or active HV-CMOS) 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 air flow. In this contribution the CLIC vertex-detector requirements are reviewed and the current status of R&D on readout and sensors is presented.
The VELO (VErtex LOcator) at the LHCb experiment
De Capua, S.
2008-01-01
The LHCb silicon vertex locator (VELO) is an array of silicon planes installed in a retractable roman pot system, which will enable the LHCb experiment to reconstruct and trigger on b-hadrons produced in collisions at the LHC. The VELO will be also used to attempt measuring the absolute luminosity with a novel method based on vertex reconstruction of beam gas interactions. In this paper the VELO system, its construction and the results from the commissioning phase are presented. The options for a possible upgraded detector are also discussed.
Peculiar Active-Tectonic Landscape Within the Sanctuary of Zeus at Mt. Lykaion (Peloponnese, Greece)
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
Charm photoproduction using electron taggers with the zeus detector at HERA
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 GeV
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.)
Chiral symmetry breaking with the Curtis-Pennington vertex
Atkinson, D.; Gusynin, V. P.; Maris, P.
1992-01-01
Published in: Phys. Lett. B 303 (1993) 157-162 citations recorded in [Science Citation Index] Abstract: We study chiral symmetry breaking in quenched QED$_4$, using a vertex Ansatz recently proposed by Curtis and Pennington. Bifurcation analysis is employed to establish the existence of a critical c
Track and vertex finding performance with the CMS inner tracker
Caner, A; Khanov, A I; Stepanov, N
1999-01-01
The Compact Muon Solenoid (CMS) Tracker Collaboration has recently finalised the design of the tracking detector. After characterising the detector layout, we review in detail the algorithms developed for track and vertex reconstruction. We discuss the reconstruction capability for several benchmark event topologies and assess the projected performance of the CMS tracking detector. (12 refs).
Approximation Algorithms for Edge Partitioned Vertex Cover Problems
Bera, Suman Kalyan; Kumar, Amit; Roy, Sambuddha
2011-01-01
In the Partial Vertex Cover (PVC) problem we are given an undirected graph G = (V, E), a positive cost associated with each vertex and a positive integer k and the goal is to find a minimum cost subset of vertices S such that atleast k edges of the graph are covered. In this paper we consider two new generalization of the PVC problem. In the first variation which we call Partition Vertex Cover (Partition-VC) problem, the edges of the graph G are divided into n disjoint partitions $P_1, P_2... P_n$ and we have to select a minimum cost subset of vertices S such that atleast $k_i$ edges are covered from partition $P_i$. In the second variation which we call Knapsack Partition Vertex Cover (KPVC) problem, in addition to the previous conditions, each edge e has a profit $\\pi_{e}$ associated with it and we have an added knapsack constraint that the total profit of the covered edges in partition $P_i$ should be atleast $\\Pi_i$. We give an $O(log n)$ approximation for both the problems using a combination of determin...
One vertex spin-foams with the Dipole Cosmology boundary
Kisielowski, Marcin; Puchta, Jacek
2012-01-01
We find all the spin-foams contributing in the first order of the vertex expansion to the transition amplitude of the Bianchi-Rovelli-Vidotto Dipole Cosmology model. Our algorithm is general and provides spin-foams of arbitrarily given, fixed: boundary and, respectively, a number of internal vertices. We use the recently introduced Operator Spin-Network Diagrams framework.
A cohomology theory of grading-restricted vertex algebras
Huang, Yi-Zhi
2010-01-01
We introduce a cohomology theory of grading-restricted vertex algebras. To construct the "correct" cohomologies, we consider linear maps from tensor powers of a grading-restricted vertex algebra to "rational functions valued in the algebraic completion of a module for the algebra," instead of linear maps from tensor powers of the algebra to a module for the algebra. One subtle complication arising from such "rational functions valued in the algebraic completion of a module" is that we have to carefully address the issue of convergence when we compose these linear maps with vertex operators. In particular, for each $n\\in \\N$, we have an inverse system $\\{H^{n}_{m}(V, W)\\}_{m\\in \\Z_{+}}$ of $n$-th cohomologies and an additional $n$-th cohomology $H_{\\infty}^{n}(V, W)$ of a grading-restricted vertex algebra $V$ with coefficients in a $V$-module $W$ such that $H_{\\infty}^{n}(V, W)$ is isomorphic to the inverse limit of the inverse system $\\{H^{n}_{m}(V, W)\\}_{m\\in \\Z_{+}}$. In the case of $n=2$, there is an addit...
A Remark on Newest Vertex Bisection in Any Space Dimension
D. Gallistl; M. Schedensack; R.P. Stevenson
2014-01-01
With newest vertex bisection, there is no uniform bound on the number of n-simplices that need to be refined to arrive at the smallest conforming refinement T′ of a conforming partition T in which one simplex has been bisected. In this note, we show that the difference in levels between any T′∈T′ an
Vertex deviation maps to bracked the Milky Way resonant radius
Roca-Fàbrega, S.; Antoja, T.; Figueras, F.; Valenzuela, O.; Romero-Gómez, M.; Pichardo, B.
2015-05-01
We map the kinematics of stars in simulated galaxy disks with spiral arms using the velocity ellipsoid vertex deviation (l_v). We use test particle simulations, and for the first time, fully self-consistent high resolution N-body models. We compare our maps with the Tight Winding Approximation model analytical predictions. We see that for all barred models spiral arms rotate closely to a rigid body manner and the vertex deviation values correlate with the density peaks position bounded by overdense and underdense regions. In such cases, vertex deviation sign changes from negative to positive when crossing the spiral arms in the direction of disk rotation, in regions where the spiral arms are in between corotation (CR) and the Outer Lindblad Resonance (OLR). By contrast, when the arm sections are inside the CR and outside the OLR, l_v changes from negative to positive.We propose that measurements of the vertex deviations pattern can be used to trace the position of the main resonances of the spiral arms. We propose that this technique might exploit future data from Gaia and APOGEE surveys. For unbarred N-body simulations with spiral arms corotating with disk material at all radii, our analysis suggests that no clear correlation exists between l_v and density structures.
Random matrices and the six-vertex model
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...
A Vertex Oriented Approach to Minimum Cost Spanning Tree Problems
Ciftci, B.B.; Tijs, S.H.
2007-01-01
In this paper we consider spanning tree problems, where n players want to be connected to a source as cheap as possible. We introduce and analyze (n!) vertex oriented construct and charge procedures for such spanning tree situations leading in n steps to a minimum cost spanning tree and a cost shari
Self-locking degree-4 vertex origami structures
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.
The role of geometry in 4-vertex origami mechanics
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.
Conservation laws, vertex corrections, and screening in Raman spectroscopy
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.
Redford, S
2015-01-01
The Compact Linear Collider is a candidate to be the next high-energy particle physics collider. Using a novel acceleration technique, electrons and positrons would be brought into collision with a centre-of-mass energy of up to 3 TeV. Despite challenging levels of beam-induced background, this would provide a relatively clean environment in which to perform precision physics measurements. The vertex detector would be crucial in achieving this, and would need to provide accurate particle tracking information to facilitate secondary vertex reconstruction and jet flavour-tagging. With this goal in mind, current technological limits are being stretched to design a low occupancy, low mass and low-power dissipation vertex detector for CLIC. A concept comprising thin hybrid pixel detectors coupled to high- performance readout ASICs, power-pulsing and air-flow cooling is under development. In this paper, the CLIC vertex detector requirements are reviewed and the current status of R&D on sensors, readout, powerin...
Two-loop and n-loop eikonal vertex corrections
Kidonakis, Nikolaos
2003-01-01
I present calculations of two-loop vertex corrections with massive and massless partons in the eikonal approximation. I show that the $n$-loop result for the UV poles can be given in terms of the one-loop calculation.
Anomalous $\\omega$-$Z$-$\\gamma$ Vertex from Hidden Local Symmetry
Harada, Masayasu; Yamawaki, Koichi
2011-01-01
We formulate the general form of omega-Z-gamma vertex in the framework based on the hidden local symmetry (HLS), which arises from the gauge invariant terms for intrinsic parity-odd (IP-odd) part of the effective action. Those terms are given as the homogeneous part of the general solution (having free parameters) to the Wess-Zumino (WZ) anomaly equation and hence are not determined by the anomaly, in sharp contrast to the Harvey-Hill-Hill (HHH) action where the relevant vertex is claimed to be uniquely determined by the anomaly. We show that, even in the framework that HHH was based on, the omega-Z-gamma vertex is actually not determined by the anomaly but by the homogeneous (anomaly-free) part of the general solution to the WZ anomaly equation having free parameters in the same way as in the HLS formulation: The HHH action is just a particular choice of the free parameters in the general solution. We further show that the omega-Z-gamma vertex related to the neutrino (nu) - nucleon (N) scattering cross secti...
W. K. H. Panofsky Prize Talk: The Silicon Vertex Trigger
Ristori, Luciano
2009-05-01
I will discuss the importance of real-time selection of events at a hadron collider, the ideas that led to the conception of the Silicon Vertex Trigger (SVT) and some historical notes on its construction and commissioning. I will also highlight some remarkable results obtained by CDF with the data selected by the SVT.
A Vertex Oriented Approach to Minimum Cost Spanning Tree Problems
Ciftci, B.B.; Tijs, S.H.
2007-01-01
In this paper we consider spanning tree problems, where n players want to be connected to a source as cheap as possible. We introduce and analyze (n!) vertex oriented construct and charge procedures for such spanning tree situations leading in n steps to a minimum cost spanning tree and a cost shari
Proposed proper Engle-Pereira-Rovelli-Livine vertex amplitude
Engle, Jonathan
2013-04-01
As established in a prior work of the author, the linear simplicity constraints used in the construction of the so-called “new” spin-foam models mix three of the five sectors of Plebanski theory as well as two dynamical orientations, and this is the reason for multiple terms in the asymptotics of the Engle-Pereira-Rovelli-Livine vertex amplitude as calculated by Barrett et al. Specifically, the term equal to the usual exponential of i times the Regge action corresponds to configurations either in sector (II+) with positive orientation or sector (II-) with negative orientation. The presence of the other terms beyond this cause problems in the semiclassical limit of the spin-foam model when considering multiple 4-simplices due to the fact that the different terms for different 4-simplices mix in the semiclassical limit, leading in general to a non-Regge action and hence non-Regge and nongravitational configurations persisting in the semiclassical limit. To correct this problem, we propose to modify the vertex so its asymptotics include only the one term of the form eiSRegge. To do this, an explicit classical discrete condition is derived that isolates the desired gravitational sector corresponding to this one term. This condition is quantized and used to modify the vertex amplitude, yielding what we call the “proper Engle-Pereira-Rovelli-Livine vertex amplitude.” This vertex still depends only on standard SU(2) spin-network data on the boundary, is SU(2) gauge-invariant, and is linear in the boundary state, as required. In addition, the asymptotics now consist in the single desired term of the form eiSRegge, and all degenerate configurations are exponentially suppressed. A natural generalization to the Lorentzian signature is also presented.
Domination parameters of a graph with added vertex
Maciej Zwierzchowski
2004-01-01
Full Text Available Let \\(G=(V,E\\ be a graph. A subset \\(D\\subseteq V\\ is a total dominating set of \\(G\\ if for every vertex \\(y\\in V\\ there is a vertex \\(x\\in D\\ with \\(xy\\in E\\. A subset \\(D\\subseteq V\\ is a strong dominating set of \\(G\\ if for every vertex \\(y\\in V-D\\ there is a vertex \\(x\\in D\\ with \\(xy\\in E\\ and \\(\\deg _{G}(x\\geq\\deg _{G}(y\\. The total domination number \\(\\gamma _{t}(G\\ (the strong domination number \\(\\gamma_{S}(G\\ is defined as the minimum cardinality of a total dominating set (a strong dominating set of \\(G\\. The concept of total domination was first defined by Cockayne, Dawes and Hedetniemi in 1980 [Cockayne E. J., Dawes R. M., Hedetniemi S. T.: Total domination in graphs. Networks 10 (1980, 211–219], while the strong domination was introduced by Sampathkumar and Pushpa Latha in 1996 [Pushpa Latha L., Sampathkumar E.: Strong weak domination and domination balance in a graph. Discrete Mathematics 161 (1996, 235–242]. By a subdivision of an edge \\(uv\\in E\\ we mean removing edge \\(uv\\, adding a new vertex \\(x\\, and adding edges \\(ux\\ and \\(vx\\. A graph obtained from \\(G\\ by subdivision an edge \\(uv\\in E\\ is denoted by \\(G\\oplus u_{x}v_{x}\\. The behaviour of the total domination number and the strong domination number of a graph \\(G\\oplus u_{x}v_{x}\\ is developed.
Limit theorems for vertex-reinforced jump processes on regular trees
Collevecchio, Andrea
2009-01-01
Consider a vertex-reinforced jump process defined on a regular tree, where each vertex has exactly $b$ children, with $b \\ge 3$. We prove the strong law of large numbers and the central limit theorem for the distance of the process from the root. Notice that it is still unknown if vertex-reinforced jump process is transient on the binary tree.
A quantum hybrid with a thin antenna at the vertex of a wedge
Carlone, Raffaele; Posilicano, Andrea
2017-03-01
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.
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.
Parameter Vertex Color Pada Animation Procedural 3D Model Vegetasi Musaceae
I Gede Ngurah Arya Indrayasa
2017-02-01
Full Text Available Penggunaan vegetasi untuk industri film, video game, simulasi, dan arsitektur visualisas merupakan faktor penting untuk menghasilkan adegan pemandangan alam lebih hidup. Penelitian ini bertujuan untuk mengetahui pengaruh dari vertex color terhadap efek angin pada animasi prosedural 3d model vegetasi musaceae serta parameter vertex color yang tepat untuk menghasilkan animasi 3d model vegetasi musaceae realistis. Hasil akhir yang di capai adalah meneliti apakah perubahan parameter vertex color dapat mempengaruhi bentuk animasi procedural 3d vegetasi musaceae serta pengaruh dari vertex color terhadap efek angin pada animasi prosedural 3d model vegetasi Musaceae. Berdasarkan pengamat dan perbandingan pada pengujian 5 sample vertex color diperoleh hasil bahwa perubahan parameter vertex color dapat mempengaruhi bentuk animasi procedural 3d vegetasi musaceae serta di peroleh kesimpulan Sample No.5 merupakan parameter vertex color yang tepat untuk menghasilkan animasi 3d model vegetasi Musaceae yang realistis. Kata kunci—3D, Animasi Prosedural, Vegetation
Measurement of neutral current e{sup {+-}}p cross sections at high Bjorken x with the ZEUS detector
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.
Measruement of beauty production in DIS and F{sub 2}{sup b} {sup anti} {sup b} extraction at ZEUS
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
Pozniak, Krzysztof T.; Adamus, Marek
1999-05-01
Background rejection power of Veto Wall detector in ZEUS experiment significantly depends on electronics and photonics efficiency. This paper describes idea, and recent solution, for programmable multi-channel optical pulser. The pulser excites, with short electrical pulses, certain light emitting diodes. LEDs are placed in scintillators. These tests simulate flight of real particles through scintillator. The scintillator works as an optical waveguide in which guides photons to both ends of scintillators. These ends are attached to photomultipliers. Photons cause avalanche multiplication of electrons and an electrical pulse resulting in registered by measuring system. Some results of pulser application are presented for diagnosis of all processing blocks of measuring system. Paper includes also, for the sake of completeness, description of the functional structure of measuring system.
Measurement of neutral current cross sections at high Bjorken-x with the ZEUS detector at HERA
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.)
An NLO QCD analysis of inclusive cross-section and jet-production data from the ZEUS experiment
Abramowicz, H; Adamczyk, L; Adamus, M; Adler, V; Aghuzumtsyan, G; Allfrey, P D; Antonioli, P; Antonov, A; Arneodo, M; Bailey, D S; Bamberger, A; Barakbaev, A N; Barbagli, G; Barbi, M; Bari, G; Barreiro, F; Bartsch, D; Basile, M; Behrens, U; Bell, M A; Bellagamba, L; Bellan, P M; Benen, A; Bertolin, A; Bhadra, S; Bloch, I; Bold, T; Boos, E G; Borras, K; Boscherini, D; Brock, I; Brook, N H; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Bussey, P J; Butterworth, J M; Büttner, C; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carli, T; Carlin, R; Cassel, D G; Catterall, C D; Chekanov, S; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, Luisa; Cindolo, F; Cole, J E; Collins-Tooth, C; Contin, A; Cooper-Sarkar, A M; Coppola, N; Corradi, M; Corriveau, F; Costa, M; Cottrell, A; Cui, Y; D'Agostini, G; Dal Corso, F; Danilov, P; De Pasquale, S; Dementiev, R K; Derrick, M; Devenish, R C E; Dhawan, S; Dobur, D; Dolgoshein, B A; Doyle, A T; Drews, G; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, Andrzej; Everett, A; Ferrando, J; Ferrero, M I; Figiel, J; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fry, C; Gabareen, A; Galas, A; Gallo, E; Garfagnini, A; Geiser, A; Genta, C; Gialas, I; Giusti, P; Gladilin, L K; Gladkov, D; Glasman, C; Göbel, F; Goers, S; Goncalo, R; González, O; Gosau, T; Göttlicher, P; Grabowska-Bold, I; Graciani-Díaz, R; Grigorescu, G; Grijpink, S; Groys, M; Grzelak, G; Gutsche, O; Gwenlan, C; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hamilton, J; Hanlon, S; Hart, C; Hartmann, H; Hartner, G; Heaphy, E A; Heath, G P; Helbich, M; Hilger, E; Hochman, D; Holm, U; Horn, C; Iacobucci, G; Iga, Y; Irrgang, P; Jakob, H P; Jiménez, M; Jones, T W; Kagawa, S; Kahle, B; Kaji, H; Kananov, S; Karshon, U; Karstens, F; Kasemann, M; Kataoka, M; Katkov, I I; Kcira, D; Keramidas, A; Khein, L A; Kim, J Y; Kind, O; Kisielewska, D; Kitamura, S; Koffeman, E; Kohno, T; Kooijman, P; Koop, T; Korzhavina, I A; Kotanski, A; Kötz, U; Kowal, A M; Kowalski, H; Kramberger, G; Kreisel, A; Krumnack, N; Kulinski, P; Kuze, M; Kuzmin, V A; Labarga, L; Lammers, S; Lelas, D; Levchenko, B B; Levy, A; Li, L; Lightwood, M S; Lim, H; Limentani, S; Ling, T Y; Liu, C; Liu, X; Löhr, B; Lohrmann, E; Loizides, J H; Long, K R; Longhin, A; Lukasik, J; Lukina, O Yu; Luzniak, P; Ma, K J; Maddox, E; Magill, S; Malka, J; Mankel, R; Margotti, A; Marini, G; Martin, J F; Martínez, M; Mastroberardino, A; Matsuzawa, K; Mattingly, M C K; Melzer-Pellmann, I A; Menary, S R; Metlica, F; Meyer, U; Miglioranzi, S; Milite, M; Mirea, A; Monaco, V; Montanari, A; Musgrave, B; Nagano, K; Namsoo, T; Nania, R; Nguyen, C N; Nigro, A; Ning, Y; Noor, U; Notz, D; Nowak, R J; Nuncio-Quiroz, A E; Oh, B Y; Olkiewicz, K; Ota, O; Padhi, S; Palmonari, F; Patel, S; Paul, E; Pavel, Usan; Pawlak, J M; Pelfer, P G; Pellegrino, A; Pesci, A; Piotrzkowski, K; Plamondon, M; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Proskuryakov, A S; Przybycien, M B; Rautenberg, J; Raval, A; Reeder, D D; Ren, Z; Renner, R; Repond, J; Ri, Y D; Rinaldi, L; Robins, S; Rosin, M; Ruspa, M; Ryan, P; Sacchi, R; Salehi, H; Santamarta, R; Sartorelli, G; Savin, A A; Saxon, D H; Schagen, S; Schioppa, M; Schlenstedt, S; Schleper, P; Schmidke, W B; Schneekloth, U; Schörner-Sadenius, T; Sciulli, F; Shcheglova, L M; Skillicorn, I O; Slominski, W; Smith, W H; Soares, M; Solano, A; Son, D; Sosnovtsev, V V; Stairs, D G; Stanco, L; Standage, J; Stifutkin, A; Stonjek, S; Stopa, P; Stösslein, U; Straub, P B; Suchkov, S; Susinno, G; Suszycki, L; Sutiak, J; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tapper, A D; Targett-Adams, C; Tassi, E; Tawara, T; Terron, J; Tiecke, H G; Tokushuku, K; Tsurugai, T; Turcato, M; Tymieniecka, T; Tyszkiewicz, A; Ukleja, A; Ukleja, J; Vázquez, M; Vlasov, N N; Voss, K C; Walczak, R; Walsh, R; Wang, M; Whitmore, J J; Whyte, J; Wichmann, K; Wick, K; Wiggers, L; Wills, H H; Wing, M; Wlasenko, M; Wolf, G; Yagues-Molina, A G; Yamada, S; Yamazaki, Y; Yoshida, R; Youngman, C; Zambrana, M; Zawiejski, L; Zeuner, W; Zhautykov, B O; Zhou, C; Zichichi, A; Ziegler, A; Zotkin, D S; Zotkin, S A; De Favereau, J; De Wolf, E; Del Peso, J
2005-01-01
The ZEUS inclusive differential cross-section data from HERA, for charged and neutral current processes taken with e+ and e- beams, together with differential cross-section data on inclusive jet production in e+ p scattering and dijet production in \\gamma p scattering, have been used in a new NLO QCD analysis to extract the parton distribution functions of the proton. The input of jet data constrains the gluon and allows an accurate extraction of \\alpha_s(M_Z) at NLO; \\alpha_s(M_Z) = 0.1183 \\pm 0.0028(exp.) \\pm 0.0008(model) An additional uncertainty from the choice of scales is estimated as \\pm 0.005. This is the first extraction of \\alpha_s(M_Z) from HERA data alone.
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.)
Measurement of neutral current cross sections at high Bjorken-$x$ with the ZEUS detector at HERA
Chekanov, S; Magill, S; Miglioranzi, S; Musgrave, B; Nicholass, D; Repond, J; Yoshida, R; Mattingly, M C K; Pavel, USAN; Yagues-Molina, A G; Antonelli, S; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Bindi, M; Boscherini, D; Bruni, A; Bruni, G; Cifarelli, L; Cindolo, F; Contin, A; Corradi, M; De Pasquale, S; Iacobucci, G; Margotti, A; Nania, R; Polini, A; Rinaldi, L; Sartorelli, G; Zichichi, A; Aghuzumtsyan, G; Bartsch, D; Brock, I; Goers, S; Hartmann, H; Hilger, E; Jakob, H P; Jüngst, M; Kind, O M; Paul, E; Rautenberg, J; Renner, R; Samson, U; Schonberg, V; Wang, M; Wlasenko, M; Brook, N H; Heath, G P; Morris, J D; Namsoo, T; Capua, M; Fazio, S; Mastroberardino, A; Schioppa, M; Susinno, G; Tassi, E; Kim, J Y; Ma, K J; Ibrahim, Z A; Kamaluddin, B; Wan-Abdullah, W A T; Ning, Y; Ren, Z; Sciulli, F; Chwastowski, J; Eskreys, Andrzej; Figiel, J; Galas, A; Gil, M; Olkiewicz, K; Stopa, P; Zaw, I; Adamczyk, L; Bold, T; Grabowska-Bold, I; Kisielewska, D; Lukasik, J; Przybycien, M B; Suszycki, L; Kotanski, A; Slominski, W; Adler, V; Behrens, U; Bloch, I; Bonato, A; Borras, K; Coppola, N; Fourletova, J; Geiser, A; Gladkov, D; Göttlicher, P; Gregor, I; Gutsche, O; Haas, T; Hain, W; Horn, C; Kahle, B; Kötz, U; Kowalski, H; Lim, H; Lobodzinska, E; Löhr, B; Mankel, R; Melzer--, I A; Pellmann; Montanari, A; Nguyen, C N; Notz, D; Nuncio-Quiroz, A E; Santamarta, R; Schneekloth, U; Spiridonov, A A; Stadie, H; Stösslein, U; Szuba, D; Szuba, J; Theedt, T; Watt, G; Wolf, G; Wrona, K; Youngman, C; Zeuner, W; Schlenstedt, S; Barbagli, G; Gallo, E; Pelfer, P G; Bamberger, A; Dobur, D; Karstens, F; Vlasov, N N; Germany; Bussey, P J; Doyle, A T; Dunne, W; Ferrando, J; Saxon, D H; Skillicorn, I O; Gialas, I; Greece; Gosau, T; Holm, U; Klanner, Robert; Lohrmann, E; Salehi, H; Schleper, P; Schörner-Sadenius, T; Sztuk, J; Wichmann, K; Wick, K; Foudas, C; Fry, C; Long, K R; Tapper, A D; Kataoka, M; Matsumoto, T; Nagano, K; Tokushuku, K; Yamada, S; Yamazaki, Y; Barakbaev, A N; Boos, E G; Dossanov, A; Pokrovskiy, N S; Zhautykov, B O; Son, D; De Favereau, J; Piotrzkowski, K; Barreiro, F; Glasman, C; Jiménez, M; Labarga, L; Del Peso, J; Ron, E; Terron, J; Zambrana, M; Corriveau, F; Liu, C; Walsh, R; Zhou, C; Tsurugai, T; Antonov, A; Dolgoshein, B A; Rubinsky, I; Sosnovtsev, V V; Stifutkin, A; Suchkov, S; Dementiev, R K; Ermolov, P F; Gladilin, L K; Katkov, I I; Khein, L A; Korzhavina, I A; Kuzmin, V A; Levchenko, B B; Lukina, O Yu; Proskuryakov, A S; Shcheglova, L M; Zotkin, D S; Zotkin, S A; Abt, I; Büttner, C; Caldwell, A; Kollar, D; Schmidke, W B; Sutiak, J; Grigorescu, G; Keramidas, A; Koffeman, E; Kooijman, P; Pellegrino, A; Tiecke, H G; Vázquez, M; Wiggers, L; Brümmer, N; Bylsma, B; Durkin, L S; Lee, A; Ling, T Y; Allfrey, P D; Bell, M A; Cooper-Sarkar, A M; Cottrell, A; Devenish, R C E; Foster, B; Gwenlan, C; Korcsak-Gorzo, K; Patel, S; Roberfroid, V; Robertson, A; Straub, P B; Uribe-Estrada, C; Walczak, R; Bellan, P M; Bertolin, A; Brugnera, R; Carlin, R; Ciesielski, R; Dal Corso, F; Dusini, S; Garfagnini, A; Limentani, S; Longhin, A; Stanco, L; Turcato, M; Raval, A; Whitmore, J J; Iga, Y; D'Agostini, G; Marini, G; Nigro, A; Cole, J E; Hart, J C; Abramowicz, H; Gabareen, A; Ingbir, R; Kananov, S; Levy, A; Kuze, M; Hori, R; Kagawa, S; Shimizu, S; Tawara, T; Hamatsu, R; Kaji, H; Kitamura, S; Ri, Y D; Ferrero, M I; Monaco, V; Sacchi, R; Solano, A; Arneodo, M; Ruspa, M; Fourletov, S; Martin, J F; Boutle, S K; Butterworth, J M; Hall-Wilton, R; Jones, T W; Loizides, J H; Sutton, M R; Targett-Adams, C; Wing, M; Brzozowska, B; Ciborowski, J; Grzelak, G; Kulinski, P; Luzniak, P; Malka, J; Nowak, R J; Pawlak, J M; Tymieniecka, T; Ukleja, A; Ukleja, J; Adamus, M; Plucinsky, P P; Eisenberg, Y; Giller, I; Hochman, D; Karshon, U; Rosin, M; Brownson, E; Danielson, T; Everett, A; Kcira, D; Reeder, D D; Ryan, P; Savin, A A; Smith, W H; Wolfe, H
2007-01-01
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 $\\pbi$ for $e^+p$ collisions and 16.7 $\\pbi$ for $e^-p$ collisions at $\\sqrt{s}=318$ $\\gev$ and 38.6 $\\pbi$ for $e^+p$ collisions at $\\sqrt{s}=300$ $\\gev$. Cross sections have been extracted for $Q^2 \\ge 648$ $\\gev^{2}$ 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.
Measurement of neutral current e+/-p cross sections at high Bjorken x with the ZEUS detector
Abramowicz, H; Adamczyk, L; Adamus, M; Aggarwal, R; Antonelli, S; Arslan, O; Aushev, V; Aushev, Y; Bachynska, O; Barakbaev, A N; Bartosik, N; Behnke, O; Behr, J; Behrens, U; Bertolin, A; Bhadra, S; Bloch, I; Bokhonov, V; Boos, E G; Borras, K; Brock, I; Brugnera, R; Bruni, A; Brzozowska, B; Bussey, P J; Caldwell, A; Capua, M; Catterall, C D; Chwastowski, J; Ciborowski, J; Cooper-Sarkar, A M; Corradi, M; Corriveau, F; Agostini, G D; Dementiev, R K; Devenish, R C E; Dolinska, G; Drugakov, V; Dusini, S; Ferrando, J; Figiel, J; Foster, B; Gach, G; Garfagnini, A; Geiser, A; Gizhko, A; Gladilin, L K; Gogota, O; Golubkov, Yu A; Grebenyuk, J; Gregor, I; Grzelak, G; Gueta, O; Guzik, M; Hain, W; Hartner, G; Hochman, D; Hori, R; Ibrahim, Z A; Iga, Y; Ishitsuka, M; Iudin, A; Januschek, F; Kadenko, I; Kananov, S; Kanno, T; Karshon, U; Kaur, M; Kaur, P; Khein, L A; Kisielewska, D; Klanner, R; Klein, U; Kondrashova, N; Kononenko, O; Korol, Ie; Korzhavina, I A; Kotanski, A; Koetz, U; Kovalchuk, N; Kowalski, H; Kuprash, O; Kuze, M; Levchenko, B B; Levy, A; Libov, V; Limentani, S; Lisovyi, M; Lobodzinska, E; Lohmann, W; Loehr, B; Lohrmann, E; Longhin, A; Lontkovskyi, D; Lukina, O Yu; Maeda, J; Makarenko, I; Malka, J; Martin, J F; Mergelmeyer, S; Idris, F Mohamad; Mujkic, K; Myronenko, V; Nagano, K; Nigro, A; Nobe, T; Notz, D; Nowak, R J; Olkiewicz, K; Onishchuk, Yu; Paul, E; Perlanski, W; Perrey, H; Pokrovskiy, N S; Proskuryakov, A S; Przybycien, M; Raval, A; Roloff, P; Rubinsky, I; Ruspa, M; Samojlov, V; Saxon, D H; Schioppa, M; Schmidke, W B; Schneekloth, U; Schoerner-Sadenius, T; Schwartz, J; Shcheglova, L M; Shevchenko, R; Shkola, O; Singh, I; Skillicorn, I O; Slominski, W; Sola, V; Solano, A; Spiridonov, A; Stanco, L; Stefaniuk, N; Stern, A; Stewart, T P; Stopa, P; Sztuk-Dambietz, J; Szuba, D; Szuba, J; Tassi, E; Temiraliev, T; Tokushuku, K; Tomaszewska, J; Trofymov, A; Trusov, V; Tsurugai, T; Turcato, M; Turkot, O; Tymieniecka, T; Verbytskyi, A; Viazlo, O; Walczak, R; Abdullah, W A T Wan; Wichmann, K; Wing, M; Wolf, G; Yamada, S; Yamazaki, Y; Zakharchuk, N; Zarnecki, A F; Zawiejski, L; Zenaiev, O; Zhautykov, B O; Zhmak, N; Zotkin, D S
2013-01-01
The neutral current e+/-p cross section has been measured up to values of Bjorken x of approximately 1 with the ZEUS detector at HERA using an integrated luminosity of 187 inv. pb of e-p and 142 inv. pb of e+p collisions at sqrt(s) = 318GeV. Differential cross sections in x and Q2, the exchanged boson virtuality, are presented for Q2 geq 725GeV2. 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.
Worldline calculation of the three-gluon vertex
Ahmadiniaz, N.; Schubert, C. [Dipartimento di Fisica, Universita di Bologna and INFN Sezione di Bologna Via Irnerio 46, I-40126 Bologna (Italy); Instituto de Fisica y Matematicas Universidad Michoacana de San Nicolas de Hidalgo Apdo. Postal 2-82 C.P. 58040, Morelia, Michoacan (Mexico)
2012-10-23
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.
Six-vertex models and the GUE-corners process
Dimitrov, Evgeni
2016-01-01
In this paper we consider a class of probability distributions on the six-vertex model from statistical mechanics, which originate from the higher spin vertex models of https://arxiv.org/abs/1601.05770. We define operators, inspired by the Macdonald difference operators, which extract various correlation functions, measuring the probability of observing different arrow configurations. The development of our operators is largely based on the properties of a remarkable family of symmetric rational functions, which were previously studied in https://arxiv.org/abs/1410.0976. For the class of models we consider, the correlation functions can be expressed in terms of multiple contour integrals, which are suitable for asymptotic analysis. For a particular choice of parameters we analyze the limit of the correlation functions through a steepest descent method. Combining this asymptotic statement with some new results about Gibbs measures on Gelfand-Tsetlin cones and patterns, we show that the asymptotic behavior of o...
K-vertex-connectivity minimum augmentation for undirected unweighted graphs
无
2003-01-01
For an undirected unweighted graph G0＝(V0,E0) and a positive integer K, the K-vertex-connectivity minimum augmentation problem (K-VCMAP) is to find a minimum set of edges Emin such that the graph H0＝(V0,E0∪Emin) is K-vertex-connected. Results in the literature have given polynomial time algorithms for K-VCMAP in several special cases such as where k≤3, or G0 is a tree. However, it still remains open whether or not there exist polynomial time algorithms for K-VCMAP for any graph G0 and any integer K. In this paper, we settle the problem by describing an efficient algorithm (KUCA) with time-complexity of O(K|V(G0)|5) for the K-VCMAP for any G0 and any positive integer K.
Exploratory study of the 3-gluon vertex on the lattice
Parrinello, C
1994-01-01
We define and evaluate on the lattice the amputated 3-gluon vertex function in momentum space. We give numerical results for 16^3 \\times 40 and 24^3 \\times 40 quenched lattices at \\beta=6.0. A good numerical signal is obtained, at the price of enforcing the gauge-fixing condition with high accuracy. By comparing results from two different lattice volumes, we try to investigate the crucial issue of finite volume effects. We also outline a method for the lattice evaluation of the QCD running coupling constant as defined from the 3-gluon vertex, while being aware that a realistic calculation will require larger \\beta values and very high statistics.
On the zero crossing of the three-gluon vertex
A. Athenodorou
2016-10-01
Full Text Available 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.
On the zero crossing of the three-gluon vertex
Athenodorou, A.; Binosi, D.; Boucaud, Ph.; De Soto, F.; Papavassiliou, J.; Rodríguez-Quintero, J.; Zafeiropoulos, S.
2016-10-01
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.
Integrable mixing of A_{n-1} type vertex models
Grillo, S
2002-01-01
Given a family of monodromy matrices {T_u; u=1,...,K} corresponding to integrable anisotropic vertex models of A_{n_u-1}-type, we build up a related mixed vertex model by means of gluing the lattices on which they are defined, in such a way that integrability property is preserved. Algebraically, the gluing process is implemented through one dimensional representations of rectangular matrix algebras A(R_p,R_q), where R_n indicates the R-matrix associated to the standard Hopf algebra deformation of the simple Lie algebra A_{n-1}. We show that algebraic Bethe ansatz can be applied, and the resulting nested equations are identical to the ones corresponding to an A_{n-1} quasi- periodic model with n=min{n_u; u=1,...,K}.
3-state Hamiltonians associated to solvable 33-vertex models
Crampé, N.; Frappat, L.; Ragoucy, E.; Vanicat, M.
2016-09-01
Using the nested coordinate Bethe ansatz, we study 3-state Hamiltonians with 33 non-vanishing entries, or 33-vertex models, where only one global charge with degenerate eigenvalues exists and each site possesses three internal degrees of freedom. In the context of Markovian processes, they correspond to diffusing particles with two possible internal states which may be exchanged during the diffusion (transmutation). The first step of the nested coordinate Bethe ansatz is performed providing the eigenvalues in terms of rapidities. We give the constraints ensuring the consistency of the computations. These rapidities also satisfy Bethe equations involving 4 × 4 R-matrices, solutions of the Yang-Baxter equation which implies new constraints on the models. We solve them allowing us to list all the solvable 33-vertex models.
Internal alignement of the BABAR silicon vertex tracking detector
Brown, D; Roberts, D
2007-01-01
The BABAR Silicon Vertex Tracker (SVT ) is a five-layer double-sided silicon detector designed to provide precise measurements of the position and direction of primary tracks, and to fully reconstruct low-momentum tracks produced in e+e¡ collisions at the PEP-II asymmetric collider at Stanford Linear Accelerator Center. This paper describes the design, implementation, performance and validation of the local alignment procedure used to determine the relative positions and orientations of the 340 Silicon Vertex Trackerwafers. This procedure uses a tuned mix of lab-bench measurements and complementary in-situ experimental data to control systematic distortions. Wafer positions and orientations are determined by minimizing a Â2 computed using these data for each wafer individually, iterating to account for between-wafer correlations. A correction for aplanar distortions of the silicon wafers is measured and applied. The net effect of residual mis-alignments on relevant physical variables evaluated in special co...
On the zero crossing of the three-gluon vertex
Athenodorou, A; Boucaud, Ph; De Soto, F; Papavassiliou, J; Rodriguez-Quintero, J; Zafeiropoulos, S
2016-01-01
We report on new results on the infrared behaviour of the three-gluon vertex in quenched Quantum Chormodynamics, 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.
Diagonalization of the XXZ Hamiltonian by Vertex Operators
Davies, B; Jimbo, M; Miwa, T; Nakayashiki, A; Davies, Brian; Foda, Omar; Jimbo, Michio; Miwa, Tetsuji; Nakayashiki, Atsushi
1993-01-01
We diagonalize the anti-ferroelectric XXZ-Hamiltonian directly in the thermodynamic limit, where the model becomes invariant under the action of affine U_q( sl(2) ). Our method is based on the representation theory of quantum affine algebras, the related vertex operators and KZ equation, and thereby bypasses the usual process of starting from a finite lattice, taking the thermodynamic limit and filling the Dirac sea. From recent results on the algebraic structure of the corner transfer matrix of the model, we obtain the vacuum vector of the Hamiltonian. The rest of the eigenvectors are obtained by applying the vertex operators, which act as particle creation operators in the space of eigenvectors. We check the agreement of our results with those obtained using the Bethe Ansatz in a number of cases, and with others obtained in the scaling limit --- the $su(2)$-invariant Thirring model.
The secondary vertex finding algorithm with the ATLAS detector
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.
OPAL Central Detector (Including vertex, jet and Z chambers)
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.
Vertex detectors: The state of the art and future prospects
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.
Silicon vertex detector upgrade in the ALPHA experiment
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.
Silicon vertex detector upgrade in the ALPHA experiment
Amole, C.; Andresen, G. B.; 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.; Stracka, S.; Sampson, J. A.; Sarid, E.; Seddon, D.; Silveira, D. M.; So, C.; Thompson, R. I.; Tharp, T.; Thornhill, J.; Tooley, M. P.; van der Werf, D. P.; Wells, D.
2013-12-01
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.
Vertex-based diffusion for 3-D mesh denoising.
Zhang, Ying; Ben Hamza, A
2007-04-01
We present a vertex-based diffusion for 3-D mesh denoising by solving a nonlinear discrete partial differential equation. The core idea behind our proposed technique is to use geometric insight in helping construct an efficient and fast 3-D mesh smoothing strategy to fully preserve the geometric structure of the data. Illustrating experimental results demonstrate a much improved performance of the proposed approach in comparison with existing methods currently used in 3-D mesh smoothing.
Vertex Operators for Irregular Conformal Blocks: Supersymmetric Case
Polyakov, Dimitri
2016-01-01
We construct supersymmetric irregular vertex operators of arbitrary rank, appearing in the colliding limit of primary fields. We find that the structure of the supersymmetric irregular vertices differs significantly from the bosonic case: upon supersymmetrization, the irregular operators are no longer the eigenstates of positive Virasoro and $W_N$ generators but block-diagonalize them. We relate the block-diagonal structure of the irregular vertices to contributions of the Ramond sector to the colliding limit.
Recent status of FPCCD vertex detector R&D
Murai, S; Sanuki, T; Miyamoto, A; Sugimoto, Y; Constantino, C; Sato, H; Ikeda, H; Hitoshi, H
2016-01-01
The Fine Pixel CCD (FPCCD) is one of the candidate sensor technologies for the ILC vertex detector. It will be located near interaction point and require high radiation tolerance. It will thus be operated at -40 degree C to improve radiation tolerance. In this paper, we report on the status of neutron radiation tests, on a cooling system using two-phase CO2 with a gas compressor for circulation, and on the mechanical structure of the FPCCD ladders.
Q-operators in the six-vertex model
Vladimir V. Mangazeev
2014-09-01
Here we use a different strategy and construct Q-operators as integral operators with factorized kernels based on the original Baxter's method used in the solution of the eight-vertex model. We compare this approach with the method developed in [1] and find the explicit connection between two constructions. We also discuss a reduction to the case of finite-dimensional representations with (half-integer spins.
Silicon vertex detector upgrade in the ALPHA experiment
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.
General Vertex-Distinguishing Total Coloring of Graphs
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.
Factorized domain wall partition functions in trigonometric vertex models
Foda, O; Zuparic, M
2007-01-01
We obtain factorized domain wall partition functions for two sets of trigonometric vertex models: 1. The N-state Deguchi-Akutsu models, for N = {2, 3, 4} (and conjecture the result for all N >= 5), and 2. The sl(r+1|s+1) Perk-Schultz models, for {r, s = \\N}, where (given the symmetries of these models) the result is independent of {r, s}.
String loop corrections from fusion of handles and vertex operators
Ooguri, H.; Sakai, N.
1987-10-01
Handle operators are introduced to describe nonlinear sigma models on higher genus surfaces by an operator formalism. Operator product expansions (fusions) among handle and vertex operators provide new sources of conformal symmetry breakings. Through the renormalization group equations, string-loop corrected equations of motion without one-particle reducible parts are derived to one-loop order. Work supported in part by Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture (No. 61540200).
A neural network z-vertex trigger for Belle II
Neuhaus, Sara; Abudinén, Fernando; Chen, Yang; Feindt, Michael; Frühwirth, Rudolf; Heck, Martin; Kiesling, Christian; Knoll, Alois; Paul, Stephan; Schieck, Jochen
2014-01-01
We present the concept of a track trigger for the Belle II experiment, based on a neural network approach, that is able to reconstruct the z (longitudinal) position of the event vertex within the latency of the first level trigger. The trigger will thus be able to suppress a large fraction of the dominating background from events outside of the interaction region. The trigger uses the drift time information of the hits from the Central Drift Chamber (CDC) of Belle II within narrow cones in polar and azimuthal angle as well as in transverse momentum (sectors), and estimates the z-vertex without explicit track reconstruction. The preprocessing for the track trigger is based on the track information provided by the standard CDC trigger. It takes input from the 2D ($r - \\varphi$) track finder, adds information from the stereo wires of the CDC, and finds the appropriate sectors in the CDC for each track in a given event. Within each sector, the z-vertex of the associated track is estimated by a specialized neural ...
Flattening single-vertex origami: the non-expansive case
Panina, Gaiane
2010-01-01
A single-vertex origami is a piece of paper with straight-line rays called creases emanating from a fold vertex placed in its interior or on its boundary. The Single-Vertex Origami Flattening problem asks whether it is always possible to reconfigure the creased paper from any configuration compatible with the metric, to a flat, non-overlapping position, in such a way that the paper is not torn, stretched and, for rigid origami, not bent anywhere except along the given creases. Streinu and Whiteley showed how to reduce the problem to the carpenter's rule problem for spherical polygons. Using spherical expansive motions, they solved the cases of open < \\pi and closed <= 2\\pi spherical polygons. Here, we solve the case of open polygons with total length between [\\pi, 2\\pi), which requires non-expansive motions. Our motion planning algorithm works in a finite number of discrete steps, for which we give precise bounds depending on both the number of links and the angle deficit.
Colour-independent partition functions in coloured vertex models
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.
cellGPU: Massively parallel simulations of dynamic vertex models
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
Transverse Ward-Takahashi Relation for the Vector Vertex in Quantum Field Theory
HE Han-Xin
2001-01-01
The transverse Ward-Takahashi (W-T) relation for the vector vertex in quantum field theory is derived by calculating the curl of the time-ordered product of the three-point function including the vector current operator. This provides the constraint on the transverse part of the vertex. By combining the transverse and normal (longitudinal)W-T identities, we obtain the expression for the full vector vertex function.``
Freely generated vertex algebras and non-linear Lie conformal algebras
De Sole, Alberto; Kac, Victor
2003-01-01
We introduce the notion of a non--linear Lie conformal superalgebra and prove a PBW theorem for its universal enveloping vertex algebra. We also show that conversely any graded freely generated vertex algebra is the universal enveloping algebra of a non--linear Lie conformal superalgebra. This correspondence will be applied in the subsequent work to the problem of classification of finitely generated simple graded vertex algebras.
2008-01-01
We discuss approximations of vertex couplings of quantum graphs using families of thin branched manifolds. We show that if a Neumann type Laplacian on such manifolds is amended by suitable potentials, the resulting Schr\\"odinger operators can approximate non-trivial vertex couplings. The latter include not only the delta-couplings but also those with wavefunctions discontinuous at the vertex. We work out the example of the symmetric delta'-couplings and conjecture that the same method can be ...
Vertex Operators Arising from Jacobi-Trudi Identities
Jing, Naihuan; Rozhkovskaya, Natasha
2016-09-01
We give an interpretation of the boson-fermion correspondence as a direct consequence of the Jacobi-Trudi identity. This viewpoint enables us to construct from a generalized version of the Jacobi-Trudi identity the action of a Clifford algebra on the polynomial algebras that arrive as analogues of the algebra of symmetric functions. A generalized Giambelli identity is also proved to follow from that identity. As applications, we obtain explicit formulas for vertex operators corresponding to characters of the classical Lie algebras, shifted Schur functions, and generalized Schur symmetric functions associated to linear recurrence relations.
Vertex Normals and Face Curvatures of Triangle Meshes
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.
Movable radiation shields for the CLEO II silicon vertex detector
Dumas, D.J.; Ward, C.W.; Alexander, J.; Cherwinka, J.; Henderson, S. [Cornell Univ., Ithaca, NY (United States); Cinabro, D. [Harvard University, Cambridge, MA 02138 (United States); Fast, J. [Purdue University, Lafayette, IN 47907 (United States); Morrison, R. [University of California at Santa Barbara, Santa Barbara, CA 93106 (United States); O`Neill, M. [CRPP, Carleton University, Ottawa, Ont. (Canada)
1998-02-11
Two movable tungsten radiation shields were installed on the beam pipe during the upgrade of the CLEO II detector, operating at the Cornell electron storage ring (CESR). This upgrade included the installation of a silicon vertex detector (SVX) and the purpose of the shields is to protect the SVX readout electronics from synchrotron radiation produced during injection and non-high-energy physics operation of CESR. Shield motion is controlled remotely by cables, keeping the associated motors and controls outside the detection volume. We discuss the design and performance of the radiation shields and the associated control system. (orig.). 8 refs.
New Hybrid Genetic Algorithm for Vertex Cover Problems
霍红卫; 许进
2003-01-01
This paper presents a new hybrid genetic algorithm for the vertex cover problems in which scan-repair and local improvement techniques are used for local optimization. With the hybrid approach, genetic algorithms are used to perform global exploration in a population, while neighborhood search methods are used to perform local exploitation around the chromosomes. The experimental results indicate that hybrid genetic algorithms can obtain solutions of excellent quality to the problem instances with different sizes. The pure genetic algorithms are outperformed by the neighborhood search heuristics procedures combined with genetic algorithms.
The vacuum system of the LHCb vertex detector
Van den Brand, J F J; Kraan, M G; Klous, S; Kaan, A P
2002-01-01
An overview of the design of the vertex detector of the LHCb experiment in the future Large Hadron Collider at CERN will be given. The application of silicon detectors close to the beam implies the isolation of the materials with a high desorption rate from the accelerator vacuum. The aluminium containment has a complicated shape and a thickness of 250 mu m in order to minimize the multiple scattering. Alignment, safety and precision problems have been solved in the design and are being tested. (1 refs).
Monitoring the stability of the ALEPH vertex detector
Sguazzoni, G.; Creanza, D.; De Palma, M.; Maggi, G.; Raso, G.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Burns, M.; Frank, M.; Maley, P.D.; Morel, M.; Wagner, A.; Focardi, E.; Parrini, G.; Scarlini, E.; Halley, A.; O' Shea, V.; Raine, C.; Barber, G.; Cameron, W.; Dornan, P.; Gentry, D.; Moutoussi, A.; Nash, J.; Price, D.; Stacey, A.; Toudup, L.W.; Williams, M.I.; Billault, M.; Blanc, P.E.; Bonissent, A.; Bujosa, G.; Calvet, D.; Carr, J.; Coyle, P.; Curtil, C.; Destelle, J.J.; Diaconu, C.; Fouchez, D.; Karst, P.; Payre, P.; Rousseau, D.; Thulasidas, M.; Dietl, H.; Ganis, G.; Moser, H.G.; Settles, R.; Seywerd, H.; Waltermann, G.; Bosi, F.; Bozzi, C.; Dell' Orso, R.; Profeti, A.; Rizzo, G.; Verdini, P.G.; Bizzell, J.P.; Thompson, J.C.; Black, S.; Dann, J.; Kim, H.Y.; Konstantinidis, N.; Taylor, G.; Bosisio, L.; Rothberg, J.; Wasserbaech, S.; Armstrong, S.; Elmer, P.; Walsh, J
1999-08-01
The ALEPH Silicon Vertex Detector features an optical fibre laser system to monitor its mechanical stability. The operating principle and the general performance of the laser system are described. The experience obtained during 1997 and 1998 operations confirms the important role that such a system can have with respect to the detector alignment requirements. In particular, the laser system has been used to monitor short-term temperature-related effects and long-term movements. These results and a description of the laser-based alignment correction applied to the 1998 data are presented.
Monitoring the Stability of the ALEPH Vertex Detector
Sguazzoni, G; De Palma, M; Maggi, G; Raso, G; Selvaggi, G; Silvestris, L; Tempesta, P; Burns, M; Frank, M; Maley, P; Morel, M; Wagner, A; Focardi, E; Parrini, G; Scarlini, E; Halley, A W; O'Shea, V; Raine, C; Barber, G J; Cameron, W; Dornan, Peter J; Gentry, D; Moutoussi, A; Nash, J; Price, D; Stacey, A M; Toudup, L W; Williams, M I; Billault, M; Blanc, P E; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Coyle, P; Curtil, C; Destelle, J J; Diaconu, C A; Fouchez, D; Karst, P; Payre, P; Rousseau, D; Thulasidas, M; Dietl, H; Ganis, G; Moser, H G; Settles, Ronald; Seywerd, H C J; Waltermann, G; Bosi, F; Bozzi, C; Dell'Orso, R; Profeti, A; Rizzo, G; Verdini, P G; Bizzell, J P; Thompson, J C; Black, S; Dann, J H; Kim, H Y; Konstantinidis, N P; Taylor, G; Bosisio, L; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Elmer, P; Walsh, J
1999-01-01
The ALEPH Silicon Vertex Detector features an optical fibre laser system to monitor its mechanical stability. The operating principle and the general performance of the laser system are described. The experience obtained during 1997 and 1998 operations confirms the important role that such a system can have with respect to the detector alignment requirements. In particular, the laser system has been used to monitor short-term temperature-related effects and long-term movements. These results and a description of the laser-based alignment correction applied to the 1998 data are presented.
A DNA computer model for solving vertex coloring problem
XU Jin; QIANG Xiaoli; FANG Gang; ZHOU Kang
2006-01-01
A special DNA computer was designed to solve the vertex coloring problem. The main body of this kind of DNA computer was polyacrylamide gel electrophoresis which could be classified into three parts: melting region, unsatisfied solution region and solution region. This polyacrylamide gel was connected with a controllable temperature device, and the relevant temperature was Tm1, Tm2 and Tm3, respectively. Furthermore, with emphasis on the encoding way, we succeeded in performing the experiment of a graph with 5 vertices. In this paper we introduce the basic structure, the principle and the method of forming the library DNA sequences.
A new tool for constrained vertex fitting in ATLAS
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.
W-symmetry, topological vertex and affine Yangian
Procházka, Tomáš
2015-01-01
We discuss the representation theory of non-linear chiral algebra $\\mathcal{W}_{1+\\infty}$ of Gaberdiel and Gopakumar and its connection to Yangian of $\\hat{\\mathfrak{u}(1)}$ whose presentation was given by Tsymbaliuk. The characters of completely degenerate representations of $\\mathcal{W}_{1+\\infty}$ are for generic values of parameters given by the topological vertex. The Yangian picture provides an infinite number of commuting charges which can be explicitly diagonalized in $\\mathcal{W}_{1+\\infty}$ highest weight representations. Many properties that are difficult to study in $\\mathcal{W}_{1+\\infty}$ picture turn out to have a simple combinatorial interpretation.
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
Davis, G. H.
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! 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
EMC studies for the vertex detector of the Belle II experiment
Thalmeier, R.; Iglesias, M.; Arteche, F.; Echeverria, I.; Friedl, M.; Adamczyk, K.; Aihara, H.; Angelini, C.; Aziz, T.; Babu, V.; Bacher, S.; Bahinipati, S.; Barberio, E.; Baroncelli, T.; Basith, A. K.; Batignani, G.; Bauer, A.; Behera, P. K.; Bergauer, T.; Bettarini, S.; Bhuyan, B.; Bilka, T.; Bosi, F.; Bosisio, L.; Bozek, A.; Buchsteiner, F.; Casarosa, G.; Ceccanti, M.; Cervenkov, D.; Chendvankar, S. R.; Dash, N.; Divekar, S. T.; Doležal, Z.; Dutta, D.; Forti, F.; Hara, K.; Higuchi, T.; Horiguchi, T.; Irmler, C.; Ishikawa, A.; Jeon, H. B.; Joo, C.; Kandra, J.; Kang, K. H.; Kato, E.; Kawasaki, T.; Kiesling, C.; Kodyš, P.; Kohriki, T.; Koike, S.; Kolwalkar, M. M.; Kvasnicka, P.; Lanceri, L.; Lettenbicher, J.; Maki, M.; Mammini, P.; Mayekar, S. N.; Mohanty, G. B.; Mohanty, S.; Morii, T.; Moser, H. G.; Nakamura, K. R.; Natkaniec, Z.; Negishi, K.; Nisar, N. K.; Onuki, Y.; Ostrowicz, W.; Paladino, A.; Paoloni, E.; Park, H.; Pilo, F.; Profeti, A.; Rao, K. K.; Rashevskaia, I.; Rizzo, G.; Rozanska, M.; Rummel, S.; Sandilya, S.; Sasaki, J.; Sato, N.; Schultschik, S.; Schwanda, C.; Seino, Y.; Shimizu, N.; Stypula, J.; Suzuki, J.; Tanaka, S.; Tanida, K.; Taylor, G. N.; Thomas, R.; Tsuboyama, T.; Uozumi, S.; Urquijo, P.; Vitale, L.; Volpi, M.; Watanuki, S.; Watson, I. J.; Webb, J.; Wiechczynski, J.; Williams, S.; Würkner, B.; Yamamoto, H.; Yin, H.; Yoshinobu, T.
2016-01-01
The upgrade of the Belle II experiment plans to use a vertex detector based on two different technologies, DEPFET pixel (PXD) technology and double side silicon microstrip (SVD) technology. The vertex electronics are characterized by the topology of SVD bias that forces to design a sophisticated grounding because of the floating power scheme. The complex topology of the PXD power cable bundle may introduce some noise inside the vertex area. This paper presents a general overview of the EMC issues present in the vertex system, based on EMC tests on an SVD prototype and a study of noise propagation in the PXD cable bundle based on Multi-conductor transmission line theory.
Effects of Vertex Activity and Self-organized Criticality Behavior on a Weighted Evolving Network
ZHANG Gui-Qing; YANG Qiu-Ying; CHEN Tian-Lun
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.
Spontaneous polarization of spin 1 analogue of the eight-vertex model
Quano, Yas-Hiro
2013-01-01
The spin 1 analogue of the eight-vertex model is considered on the basis of free field representations of vertex operators in the $2\\times 2$-fold fusion SOS model and vertex-face transformation. The spontaneous polarization of the model is obtained in terms of one-fold integral formula. Some limiting cases are discussed in order to examine the validity of the formula. Furthermore, we also present the integral formulae of the one-point function for the inhomogeneous twenty-one-vertex model.
Three-point vertex functions in Yang-Mills Theory and QCD in Landau gauge
Blum, Adrian L; Huber, Markus Q; Windisch, Andreas
2016-01-01
Solutions for the three-gluon and quark-gluon vertices from Dyson-Schwinger equations and the three-particle irreducible formalism are discussed. Dynamical quarks (``unquenching'') change the three-gluon vertex via the quark-triangle diagrams which themselves include fully dressed quark-gluon vertex functions. On the other hand, the quark-swordfish diagram is, at least with the model used for the two-quark-two-gluon vertex employed here, of minor importance. For the leading tensor structure of the three-gluon vertex the "unquenching" effect can be summarized for the nonperturbative part as a shift of the related dressing function towards the infrared.
Three-point vertex functions in Yang-Mills Theory and QCD in Landau gauge
Blum, Adrian L.; Alkofer, Reinhard; Huber, Markus Q.; Windisch, Andreas
2017-03-01
Solutions for the three-gluon and quark-gluon vertices from Dyson-Schwinger equations and the three-particle irreducible formalism are discussed. Dynamical quarks ("unquenching") change the three-gluon vertex via the quark-triangle diagrams which themselves include fully dressed quark-gluon vertex functions. On the other hand, the quark-swordfish diagram is, at least with the model used for the two-quark-two-gluon vertex employed here, of minor importance. For the leading tensor structure of the threegluon vertex the "unquenching" effect can be summarized for the nonperturbative part as a shift of the related dressing function towards the infrared.
Yarash K. Abuev; Albert B. Babaev; Pharkhat E. Esetov
2017-01-01
Objectives A computer simulation of the antiferromagnetic structures described by the three-vertex Potts model on a triangular lattice is performed, taking into account the antiferromagnetic exchange...
The Vertex-Rainbow Index of A Graph
Mao Yaping
2016-08-01
Full Text Available The k-rainbow index rxk(G of a connected graph G was introduced by Chartrand, Okamoto and Zhang in 2010. As a natural counterpart of the k-rainbow index, we introduce the concept of k-vertex-rainbow index rvxk(G in this paper. In this paper, sharp upper and lower bounds of rvxk(G are given for a connected graph G of order n, that is, 0 ≤ rvxk(G ≤ n − 2. We obtain Nordhaus-Gaddum results for 3-vertex-rainbow index of a graph G of order n, and show that rvx3(G + rvx3(Ḡ = 4 for n = 4 and 2 ≤ rvx3(G + rvx3(Ḡ ≤ n − 1 for n ≥ 5. Let t(n, k, ℓ denote the minimal size of a connected graph G of order n with rvxk(G ≤ ℓ, where 2 ≤ ℓ ≤ n − 2 and 2 ≤ k ≤ n. Upper and lower bounds on t(n, k, ℓ are also obtained.
Electronics cooling of Phenix multiplicity and vertex detector
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.
Quark-gluon vertex: A perturbation theory primer and beyond
Bermudez, R.; Albino, L.; Gutiérrez-Guerrero, L. X.; Tejeda-Yeomans, M. E.; Bashir, A.
2017-02-01
There has been growing evidence that the infrared enhancement of the form factors defining the full quark-gluon vertex plays an important role in realizing a dynamical breakdown of chiral symmetry in quantum chromodynamics, leading to the observed spectrum and properties of hadrons. Both the lattice and the Schwinger-Dyson communities have begun to calculate these form factors in various kinematical regimes of momenta involved. A natural consistency check for these studies is that they should match onto the perturbative predictions in the ultraviolet, where nonperturbative effects mellow down. In this article, we carry out a numerical analysis of the one-loop result for all the form factors of the quark-gluon vertex. Interestingly, even the one-loop results qualitatively encode most of the infrared enhancement features expected of their nonperturbative counter parts. We analyze various kinematical configurations of momenta: symmetric, on shell, and asymptotic. The on-shell limit enables us to compute anomalous chromomagnetic moment of quarks. The asymptotic results have implications for the multiplicative renormalizability of the quark propagator and its connection with the Landau-Khalatnikov-Fradkin transformations, allowing us to analyze and compare various Ansätze proposed so far.
A $z$-Vertex Trigger for Belle II
Skambraks, Sebastian; Chen, Yang; Feindt, Michael; Frühwirth, Rudolf; Heck, Martin; Kiesling, Christian; Knoll, Alois; Neuhaus, Sara; Paul, Stephan; Schieck, Jochen
2014-01-01
The Belle II experiment will go into operation at the upgraded SuperKEKB collider in 2016. SuperKEKB is designed to deliver an instantaneous luminosity $\\mathcal{L}=8\\times10^{35}\\,\\mathrm{cm}^{-2}\\,\\mathrm{s}^{-1}$. The experiment will therefore have to cope with a much larger machine background than its predecessor Belle, in particular from events outside of the interaction region. We present the concept of a track trigger, based on a neural network approach, that is able to suppress a large fraction of this background by reconstructing the $z$ (longitudinal) position of the event vertex within the latency of the first level trigger. The trigger uses the hit information from the Central Drift Chamber (CDC) of Belle II within narrow cones in polar and azimuthal angle as well as in transverse momentum ("sectors"), and estimates the $z$-vertex without explicit track reconstruction. The preprocessing for the track trigger is based on the track information provided by the standard CDC trigger. It takes input fro...
SPARTex: A Vertex-Centric Framework for RDF Data Analytics
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.
Guarding curvilinear art galleries with vertex or point guards
Karavelas, Menelaos I
2008-01-01
One of the earliest and most well known problems in computational geometry is the so-called art gallery problem. The goal is to compute the minimum possible number guards placed on the vertices of a simple polygon in such a way that they cover the interior of the polygon. In this paper we consider the problem of guarding an art gallery which is modeled as a polygon with curvilinear walls. Our main focus is on polygons the edges of which are convex arcs pointing towards the exterior or interior of the polygon (but not both), named piecewise-convex and piecewise-concave polygons. We prove that, in the case of piecewise-convex polygons, if we only allow vertex guards, $\\lfloor\\frac{4n}{7}\\rfloor-1$ guards are sometimes necessary, and $\\lfloor\\frac{2n}{3}\\rfloor$ guards are always sufficient. Moreover, an $O(n\\log{}n)$ time and $O(n)$ space algorithm is described that produces a vertex guarding set of size at most $\\lfloor\\frac{2n}{3}\\rfloor$. When we allow point guards the afore-mentioned lower bound drops down ...
The Lorentzian proper vertex amplitude: Classical analysis and quantum derivation
Engle, Jonathan
2015-01-01
Spin foam models, an approach to defining the dynamics of loop quantum gravity, make use of the Plebanski formulation of gravity, in which gravity is recovered from a topological field theory via certain constraints called simplicity constraints. However, the simplicity constraints in their usual form select more than just one gravitational sector as well as a degenerate sector. This was shown, in previous work, to be the reason for the "extra" terms appearing in the semiclassical limit of the Euclidean EPRL amplitude. In this previous work, a way to eliminate the extra sectors, and hence terms, was developed, leading to the what was called the Euclidean proper vertex amplitude. In the present work, these results are extended to the Lorentzian signature, establishing what is called the Lorentzian proper vertex amplitude. This extension is non-trivial and involves a number of new elements since, for Lorentzian bivectors, the split into self-dual and anti-self-dual parts, on which the Euclidean derivation was b...
First results with prototype ISIS devices for ILC vertex detector
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.
Natural constraints on the gluon-quark vertex
Binosi, Daniele; Papavassiliou, Joannis; Qin, Si-Xue; Roberts, Craig D
2016-01-01
In principle, the strong-interaction sector of the Standard Model is characterised by a unique renormalisation-group-invariant (RGI) running interaction and a unique form for the dressed--gluon-quark vertex, $\\Gamma_\\mu$; but, whilst much has been learnt about the former, the latter is still obscure. In order to improve this situation, we use a RGI running-interaction that reconciles both top-down and bottom-up analyses of the gauge sector in quantum chromodynamics (QCD) to compute dressed-quark gap equation solutions with 1,660,000 distinct Ansaetze for $\\Gamma_\\mu$. Each one of the solutions is then tested for compatibility with three physical criteria and, remarkably, we find that merely 0.55% of the solutions survive the test. Plainly, therefore, even a small selection of observables places extremely tight bounds on the domain of realistic vertex Ansaetze. This analysis and its results should prove useful in constraining insightful contemporary studies of QCD and hadronic phenomena.
Natural constraints on the gluon-quark vertex
Binosi, Daniele; Chang, Lei; Papavassiliou, Joannis; Qin, Si-Xue; Roberts, Craig D.
2017-02-01
In principle, the strong-interaction sector of the standard model is characterized by a unique renormalization-group-invariant (RGI) running interaction and a unique form for the dressed-gluon-quark vertex, Γμ; but, whilst much has been learnt about the former, the latter is still obscure. In order to improve this situation, we use a RGI running-interaction that reconciles top-down and bottom-up analyses of the gauge sector in quantum chromodynamics (QCD) to compute dressed-quark gap equation solutions with 1,660,000 distinct Ansätze for Γμ. Each one of the solutions is then tested for compatibility with three physical criteria and, remarkably, we find that merely 0.55% of the solutions survive the test. Evidently, even a small selection of observables places extremely tight bounds on the domain of realistic vertex Ansätze. This analysis and its results should prove useful in constraining insightful contemporary studies of QCD and hadronic phenomena.
Performance of the CLAS12 Silicon Vertex Tracker modules
Antonioli, M.A.; Boiarinov, S.; Bonneau, P.; Elouadrhiri, L.; Eng, B. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Gotra, Y., E-mail: gotra@jlab.org [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Kurbatov, E. [Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow (Russian Federation); Leffel, M.; Mandal, S.; McMullen, M. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Merkin, M. [Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow (Russian Federation); Raydo, B.; Teachey, W. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Tucker, R. [Arizona State University, Tempe, AZ (United States); Ungaro, M.; Yegneswaran, A.; Ziegler, V. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
2013-12-21
For the 12 GeV upgrade, the CLAS12 experiment has designed a Silicon Vertex Tracker (SVT) using single sided microstrip sensors fabricated by Hamamatsu. The sensors have graded angle design to minimize dead areas and a readout pitch of 156μm, with intermediate strip. Double sided SVT module hosts three daisy-chained sensors on each side with a full strip length of 33 cm. There are 512 channels per module read out by four Fermilab Silicon Strip Readout (FSSR2) chips featuring data driven architecture, mounted on a rigid-flex hybrid. Modules are assembled on the barrel using unique cantilevered geometry to minimize the amount of material in the tracking volume. Design and performance of the SVT modules are presented, focusing on results of electrical measurements. -- Highlights: •A Silicon Vertex Tracker has been designed for the central tracker of the CLAS12 experiment. •Using cantilevered module geometry allows minimizing amount of material in the tracking volume. •A dedicated Hybrid Flex Circuit Board has been developed to read out double sided module. •Module performance meets design goals of the CLAS12 Central Tracker.
[Posterior atlantoaxial fixation using vertex multiaxial screw system].
Zhong, Dejun; Song, Yueming
2007-06-01
This study aims to assess the effectiveness and advantages of Vertex multiaxial screw system in use for stabilizing the atlanto-axial junction. The entry point of the atlas was located 18-20 mm lateral to the midline and 2.0 mm superior to the inferior border of posterior arch, and the direction of screw was chosen to be about 10 degrees medial to the sagittal plane and about 5 degrees cephalad to the transverse plane. In odontoid vertebra (C2), the direction of the drill bit was guided directly by the medial and superior aspect of the individual C2 pedicle. All screws were placed properly without incidence of nerve or blood vessel injury, and no complication appeared in operation and after surgery. All cases were followed up for an average of 9 months, all cases achieved well reposition and fixation of atlantoaxial joint, average JOA grade was 9.6 before preoperation and 15.9 after operation. Fixation of the atlantoaxial complex using Vertex multiaxial screw system seemed to be a reliable technique and should be considered a good alternative in atlantoaxial fusion. The technique could be used in young patiens.
Colour-independent partition functions in coloured vertex models
Foda, O
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 [1, 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 -> infinity, and/or b_2 -> infinity, into a product of determinants, 2. Each of the la...
On the path-avoidance vertex-coloring game
Mütze, Torsten
2011-01-01
For any graph $F$ and any integer $r\\geq 2$, the \\emph{online vertex-Ramsey density of $F$ and $r$}, denoted $m^*(F,r)$, is a parameter defined via a deterministic two-player Ramsey-type game (Painter vs.\\ Builder). This parameter was introduced in a recent paper \\cite{mrs11}, where it was shown that the online vertex-Ramsey density determines the threshold of a similar probabilistic one-player game (Painter vs.\\ the binomial random graph $G_{n,p}$). For a large class of graphs $F$, including cliques, cycles, complete bipartite graphs, hypercubes, wheels, and stars of arbitrary size, a simple greedy strategy is optimal for Painter and closed formulas for $m^*(F,r)$ are known. In this work we show that for the case where $F=P_\\ell$ is a (long) path, the picture is very different. It is not hard to see that $m^*(P_\\ell,r)= 1-1/k^*(P_\\ell,r)$ for an appropriately defined integer $k^*(P_\\ell,r)$, and that the greedy strategy gives a lower bound of $k^*(P_\\ell,r)\\geq \\ell^r$. We construct and analyze Painter strat...
The Belle II silicon vertex detector assembly and mechanics
Adamczyk, K.; Aihara, H.; Angelini, C.; Aziz, T.; Babu, V.; Bacher, S.; Bahinipati, S.; Barberio, E.; Baroncelli, Ti.; Baroncelli, To.; Basith, A. K.; Batignani, G.; Bauer, A.; Behera, P. K.; Bergauer, T.; Bettarini, S.; Bhuyan, B.; Bilka, T.; Bosi, F.; Bosisio, L.; Bozek, A.; Buchsteiner, F.; Bulla, L.; Casarosa, G.; Ceccanti, M.; Červenkov, D.; Chendvankar, S. R.; Dash, N.; Divekar, S. T.; Doležal, Z.; Dutta, D.; Forti, F.; Friedl, M.; Hara, K.; Higuchi, T.; Horiguchi, T.; Irmler, C.; Ishikawa, A.; Jeon, H. B.; Joo, C. W.; Kandra, J.; Kang, K. H.; Kato, E.; Kawasaki, T.; Kodyš, P.; Kohriki, T.; Koike, S.; Kolwalkar, M. M.; Kvasnička, P.; Lanceri, L.; Lettenbicher, J.; Lueck, T.; Maki, M.; Mammini, P.; Mayekar, S. N.; Mohanty, G. B.; Mohanty, S.; Morii, T.; Nakamura, K. R.; Natkaniec, Z.; Negishi, K.; Nisar, N. K.; Onuki, Y.; Ostrowicz, W.; Paladino, A.; Paoloni, E.; Park, H.; Pilo, F.; Profeti, A.; Rashevskaya, I.; Rao, K. K.; Rizzo, G.; Rozanska, M.; Sasaki, J.; Sato, N.; Schultschik, S.; Schwanda, C.; Seino, Y.; Shimizu, N.; Stypula, J.; Suzuki, J.; Tanaka, S.; Tanida, K.; Taylor, G. N.; Thalmeier, R.; Thomas, R.; Tsuboyama, T.; Uozumi, S.; Urquijo, P.; Vitale, L.; Watanuki, S.; Watson, I. J.; Webb, J.; Wiechczynski, J.; Williams, S.; Würkner, B.; Yamamoto, H.; Yin, H.; Yoshinobu, T.
2017-02-01
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.
PROPOSAL FOR A SILICON VERTEX TRACKER (VTX) FOR THE PHENIX EXPERIMENT.
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
Di Paola, F.; Milazzo, G.; Spatafora, F.
2017-08-01
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.
Measurement of D{sup {+-}} production in deep inelastic ep scattering with the ZEUS detector at HERA
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
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.)
Neutral current cross-section measurement at low 2 and high with the ZEUS detector at HERA
Prabhdeep Kaur; on behalf of the ZEUS Collaboration
2012-11-01
The measurements of the reduced cross-sections for $e^{+} p$ deep inelastic scattering at high inelasticities for three different centre-of-mass energies, 318, 251 and 225 GeV have been extended to lower momentum transferred squared, 2. The analysis of satellite vertex events allows one to extend the cross-section measurement at high y down to 2 = 4.5 GeV2, substantially lower that the previously published cross-section measurement from which the longitudinal structure function, $F_{L}$, was extracted.
Adjacent Vertex Distinguishing Incidence Coloring of the Cartesian Product of Some Graphs
Qian WANG; Shuang Liang TIAN
2011-01-01
An adjacent vertex distinguishing incidence coloring of graph G is an incidence coloring of G such that no pair of adjacent vertices meets the same set of colors. We obtain the adjacent vertex distinguishing incidence chromatic number of the Cartesian product of a path and a path, a path and a wheel, a path and a fan, and a path and a star.
Instanton-induced Effective Vertex in the Seiberg-Witten Theory with Matter
Lee, B K; Lee, ByungKoo; Nam, Soonkeon
1997-01-01
The instanton-induced effective vertex is derived for N=2 supersymmetric QCD (SQCD) with arbitrary mass matter hypermultiplets for the case of SU(2). The leading term of the low energy effective lagrangian obtained from this vertex agrees with one-instanton effective term of the Seiberg-Witten result.
Lambda: A Mathematica-package for operator product expansions in vertex algebras
Ekstrand, Joel
2010-01-01
We give an introduction to the Mathematica package Lambda, designed for calculating {\\lambda}-brackets in both vertex algebras, and in SUSY vertex algebras. This is equivalent to calculating operator product expansions in two-dimensional conformal field theory. The syntax of {\\lambda}-brackets is reviewed, and some simple examples are shown, both in component notation, and in N=1 superfield notation.
On the Relation between Edge and Vertex Modelling in Shape Analysis
Hobolth, Asger; Kent, John Thomas; Dryden, Ian L.
2002-01-01
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...
NLO corrections to the gluon induced forward jet vertex from the high energy effective action
Chachamis, Grigorios; Madrigal, Jose Daniel; Vera, Agustin Sabio
2012-01-01
We determine both real and virtual next-to-leading order corrections to the gluon induced forward jet vertex, from the high energy effective action proposed by Lipatov. For these calculations we employ the same regularization and subtraction formalism developed in our previous work on the quark-initiated vertex. We find agreement with previous results in the literature.
On the Relation between Edge and Vertex Modelling in Shape Analysis
Hobolth, Asger; Kent, John Thomas; Dryden, Ian L.
2002-01-01
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...
Consistent off-shell pi NN vertex and nucleon self-energy
Kondratyuk, S; Scholten, O
1999-01-01
We present a consistent calculation of half-off-shell form factors in the pion-nucleon vertex and the nucleon self-energy. Numerical results are presented. Near the on-shell point the pion-nucleon vertex is dominated by the pseudovector coupling, while at large nucleon invariant masses we find a siz
Consistent off-shell πNN vertex and nucleon self-energy
Kondratyuk, S.; Scholten, O.
1999-01-01
We present a consistent calculation of half-off-shell form factors in the pion-nucleon vertex and the nucleon self-energy. Numerical results are presented. Near the on-shell point the pion-nucleon vertex is dominated by the pseudovector coupling, while at large nucleon invariant masses we find a siz
Non-perturbative model for the half-off-shell $gamma N N$ vertex
Kondratyuk, S.; Scholten, O.
1999-01-01
Submitted to: Phys. Rev. C Abstract: Form factors in the nucleon-photon vertex with one off-shell nucleon are calculated by dressing the vertex with pion loops up to infinite order. Cutting rules and dispersion relations are implemented in the model. Using the prescription of minimal substitution we
The MicroBooNE Technical Design Report
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.
Constructing Scalar-Photon Three Point Vertex in Massless Quenched Scalar QED
Fernandez-Rangel, L Albino; Gutierrez-Guerrero, L X; Concha-Sanchez, Y
2016-01-01
Non perturbative studies of Schwinger-Dyson equations (SDEs) require their infnite, 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 three point scalar-photon vertex can be expressed in terms of only two independent form factors, a longitudinal and a transverse one. 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 construct the transverse part of the non perturbative scalar-photon vertex. This construction (i) ensures multiplicative renormalizability (MR) of the scalar propagator in keeping with the Landau-Khalatnikov-Fradkin transformations (LKFTs), (ii) has the same transformatio...
The scalar-photon 3-point vertex in massless quenched scalar QED
Concha-Sánchez, Y.; Gutiérrez-Guerrero, L. X.; Fernández-Rangel, L. A.
2016-10-01
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.
A quantum hybrid with a thin antenna at the vertex of a wedge
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.
Balanced vertex decomposable simplicial complexes and their h-vectors
Biermann, Jennifer
2012-01-01
Given any finite simplicial complex \\Delta, we show how to construct a new simplicial complex \\Delta_{\\chi} that is balanced and vertex decomposable. Moreover, we show that the h-vector of the simplicial complex \\Delta_{\\chi} is precisely the f-vector, denoted f(\\Delta), of the original complex \\Delta. We deduce this result by relating f(\\Delta) with the graded Betti numbers of the Alexander dual of \\Delta_{\\chi}. Our construction generalizes the "whiskering" construction of Villarreal, and Cook and Nagel. As a corollary of our work, we add a new equivalent statement to a theorem of Bj\\"orner, Frankl, and Stanley that classifies the f-vectors of simplicial complexes. We also prove a special case of a conjecture of Cook and Nagel, and Constantinescu and Varbaro on the h-vectors of flag complexes.
Capacitively coupled hybrid pixel assemblies for the CLIC vertex detector
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.
D. phi. vertex drift chamber construction and test results
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{O} experiment at Fermilab and operated in a test beam there. Low drift velocity and diffusion properties were achieved using CO{sub 2}(95%)-ethane(5%) at atmospheric pressure. The drift velocity is found to be consistent with (9.74+8.68( E -1.25)) {mu}m/nsec where E is the electric field strength in (kV/cm < E z 1.6 kV/cm.) An intrinsic spatial resolution of 60 {mu}m 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 {mu}m. 8 refs., 6 figs., 1 tab.
A vertex similarity index for better personalized recommendation
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.
Solving Vertex Cover Problem Using DNA Tile Assembly Model
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.
A dynamical system connected with inhomogeneous 6-vertex model
Korepanov, I G
1994-01-01
A completely integrable dynamical system in discrete time is studied by means of algebraic geometry. The system is associated with factorization of a linear operator acting in a direct sum of three linear spaces into a product of three operators, each acting nontrivially only in a direct sum of two spaces, and the following reversing of the order of factors. There exists a reduction of the system interpreted as a classical field theory in 2+1-dimensional space-time, the integrals of motion coinciding, in essence, with the statistical sum of an inhomogeneous 6-vertex free-fermion model on the 2-dimensional Kagomé lattice (here the statistical sum is a function of two parameters). Thus, a connection with the "local", or "generalized", quantum Yang-Baxter equation is revealed.
New limits on anomalous contributions to the $Wtb$ vertex
Birman, J L; Fiolhais, M C N; Onofre, A; Pease, C M
2016-01-01
The latest and most precise top quark measurements at the LHC and Tevatron are used to establish new limits on the $Wtb$ vertex. Recent results on the measurements of the $W$-boson helicity fractions and single top quark production cross section are combined in order to establish new limits at 95% CL (confidence level). The allowed regions for these limits are presented, for the first time, in three-dimensional graphics, for both real and imaginary components of the different anomalous couplings, providing a new perspective on the impact of the combination of different physics observables. These results are also combined with the prospected future measurement of the single top quark production cross section and $W$-boson helicity fractions at the LHC.
Studying the $Wtb$ vertex structure using recent LHC results
Bernardo, César; Fiolhais, Miguel C N; Gonçalves, Hugo; Guerra, André G C; Oliveira, Miguel; Onofre, A
2014-01-01
The $Wtb$ vertex structure and the search for new anomalous couplings is studied using top quark measurements obtained at the LHC, for a centre-of-mass energy of 8 TeV. By combining the latest and most precise results on the single top quark production cross section and the measurements of the $W$-boson helicity fractions ($F_0$ and $F_L$), it is possible to set new limits, at 95% CL (confidence level), on the real and imaginary components of the new couplings. The combination of the LHC observables clearly improves the limits obtained when using the individual results alone. The updated measurements of the $W$-boson helicity fractions and the $s+t$-channels electroweak single top quark production, at the Tevatron, improve the LHC limits, when a world combination of all observables (LHC+Tevatron) is performed.
Performance of the ALICE secondary vertex b-tagging algorithm
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.
The silicon vertex detector of the Belle II experiment
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.
The LHCb Vertex Locator (VELO) Pixel Detector Upgrade
Buchanan, Emma
2017-01-01
The LHCb experiment is designed to perform high-precision measurements of CP violation and the decays of beauty and charm hadrons at the Large Hadron Collider (LHC) at CERN. There is a planned upgrade during Long Shutdown 2 (LS2), expected in 2019, which will allow the detector to run at higher luminosities by transforming the entire readout to a trigger-less system. This will include a substantial upgrade of the Vertex Locator (VELO), the silicon tracker that surrounds the LHCb interaction region. The VELO is moving from silicon strip technology to hybrid pixel sensors, where silicon sensors are bonded to VeloPix ASICs. Sensor prototypes have undergone rigorous testing using the Timepix3 Telescope at the SPS, CERN. The main components of the upgrade are summarised and testbeam results presented.
An integrable nineteen vertex model lying on a hypersurface
M.J. Martins
2015-03-01
Full Text Available We have found a family of solvable nineteen vertex model with statistical configurations invariant by the time reversal symmetry within a systematic study of the respective Yang–Baxter relation. The Boltzmann weights sit on a degree seven algebraic threefold which is shown birationally equivalent to the three-dimensional projective space. This permits to write parameterized expressions for both the transition operator and the R-matrix depending on three independent affine spectral parameters. The Hamiltonian limit tells us that the azimuthal magnetic field term is connected with the asymmetry among two types of spectral variables. The absence of magnetic field defines a physical submanifold whose geometrical properties are remarkably shown to be governed by a quartic K3 surface. This expands considerably the class of irrational manifolds that could emerge in the theory of quantum integrable models.
The FIRST experiment: interaction region and MAPS vertex detector
Spiriti, E. [INFN, Sezione di Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy); De Napoli, M.; Romano, F. [INFN, Laboratori Nazionali del Sud, Via S. Sofia 62, I-95125 Catania (Italy)
2011-06-15
The improvement of the precision of the measurement of the nuclear cross-section, in order to fulfill the requirements of the actual Monte Carlo simulations for hadrontherapy and space radioprotection, is the main goal of the FIRST experiment. After a brief introduction on the treatment planning in hadrontherapy, this paper describes main characteristics and components of the experiment. The features of the interaction region detectors and their main needs (low material budget, high angular coverage, two tracks resolution and large trigger rate) are discussed. Special emphasis is devoted in discussing the new silicon pixel vertex detector, in particular its new developed data acquisition and its characterization with the first test results obtained with a prototype of the detector.
The FIRST experiment: interaction region and MAPS vertex detector
Spiriti, E.; de Napoli, M.; Romano, F.; FIRST Collaboration
2011-06-01
The improvement of the precision of the measurement of the nuclear cross-section, in order to fulfill the requirements of the actual Monte Carlo simulations for hadrontherapy and space radioprotection, is the main goal of the FIRST experiment. After a brief introduction on the treatment planning in hadrontherapy, this paper describes main characteristics and components of the experiment. The features of the interaction region detectors and their main needs (low material budget, high angular coverage, two tracks resolution and large trigger rate) are discussed. Special emphasis is devoted in discussing the new silicon pixel vertex detector, in particular its new developed data acquisition and its characterization with the first test results obtained with a prototype of the detector.
The silicon vertex detector of the Belle II experiment
Adamczyk, K.; Aihara, H.; Angelini, C.; Aziz, T.; Babu, V.; Bacher, S.; Bahinipati, S.; Barberio, E.; Baroncelli, T.; Basith, A. K.; Batignani, G.; Bauer, A.; Behera, P. K.; Bergauer, T.; Bettarini, S.; Bhuyan, B.; Bilka, T.; Bosi, F.; Bosisio, L.; Bozek, A.; Buchsteiner, F.; Casarosa, G.; Ceccanti, M.; Červenkov, D.; Chendvankar, S. R.; Dash, N.; Divekar, S. T.; Doležal, Z.; Dutta, D.; Forti, F.; Friedl, M.; Hara, K.; Higuchi, T.; Horiguchi, T.; Irmler, C.; Ishikawa, A.; Jeon, H. B.; Joo, C. W.; Kandra, J.; Kang, K. H.; Kato, E.; Kawasaki, T.; Kodyš, P.; Kohriki, T.; Koike, S.; Kolwalkar, M. M.; Kvasnička, P.; Lanceri, L.; Lettenbicher, J.; Mammini, P.; Mayekar, S. N.; Mohanty, G. B.; Mohanty, S.; Morii, T.; Nakamura, K. R.; Natkaniec, Z.; Negishi, K.; Nisar, N. K.; Onuki, Y.; Ostrowicz, W.; Paladino, A.; Paoloni, E.; Park, H.; Pilo, F.; Profeti, A.; Rao, K. K.; Rashevskaya, I.; Rizzo, G.; Rozanska, M.; Sandilya, S.; Sasaki, J.; Sato, N.; Schultschik, S.; Schwanda, C.; Seino, Y.; Shimizu, N.; Stypula, J.; Tanaka, S.; Tanida, K.; Taylor, G. N.; Thalmeier, R.; Thomas, R.; Tsuboyama, T.; Uozumi, S.; Urquijo, P.; Vitale, L.; Volpi, M.; Watanuki, S.; Watson, I. J.; Webb, J.; Wiechczynski, J.; Williams, S.; Würkner, B.; Yamamoto, H.; Yin, H.; Yoshinobu, T.
2016-07-01
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.
Cutaneous paraganglioma of the vertex in a child.
Kim; Lee, Il Jae; Park, Myong Chul; Kim, Joo Hyoung; Lim, Hyoseob
2012-07-01
Paraganglioma is a neuroendocrine neoplasm that may develop at various body sites, including the head, neck, thorax, and abdomen. Approximately 85% of paragangliomas develop on the abdomen, 12% develop on the chest, and only 3% develop on the head and neck. These tumors are found in locations that parallel the sympathetic chain ganglion in the thoracolumbar regions and parasympathetic nervous system in craniosacral regions, and all head and neck paragangliomas arise from the parasympathetic nervous system. Although the skin has a rich neural network, it is devoid of ganglia. There has been only 1 report of a paraganglioma on the scalp of a child. We describe a 3-year-old child with a primary cutaneous paraganglioma of the vertex scalp and review the literature on paragangliomas.
Vertex partitions of r-edge-colored graphs
JIN Ze-min; LI Xue-liang
2008-01-01
Let G be an edge-colored graph. The monochromatic tree partition problem is to find the minimum number of vertex disjoint monochromatic trees to cover the all vertices of G. In the authors' previous work,it has been proved that the problem is NP-complete and there does not exist any constant factor approximation algorithm for it unless P = NP. In this paper the authors show that for any fixed integer r ≥ 5,if the edges of a graph G are colored by r colors,called an r-edge-colored graph,the problem remains NP-complete. Similar result holds for the monochromatic path (cycle) partition problem. Therefore,to find some classes of interesting graphs for which the problem can be solved in polynomial time seems interesting.A linear time algorithm for the monochromatic path partition problem for edge-colored trees is given.
Quark-gluon vertex dressing and meson masses beyond ladder-rainbow truncation
Hrayr Matevosyan; Anthony Thomas; Peter Tandy
2007-04-01
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. With the more consistent vertex used here, the error in ladder-rainbow truncation for vector mesons is never more than 10% as the current quark mass is varied from the u/d region to the b region.
Progress toward the Determination of Complete Vertex Operators for The IIB Matrix Model
Kitazawa, Y; Saito, O; Kitazawa, Yoshihisa; Mizoguchi, Shun'ya; Saito, Osamu
2006-01-01
We report on progress in determining the complete form of vertex operators for the IIB matrix model. The exact expressions are obtained for those emitting massless IIB supergravity fields up to sixth order in the light-cone superfield, in which the conjugate gravitino and conjugate two-form vertex operators are newly determined. We also provide a consistency check by computing the kinematical factor of a four-point graviton amplitude in a D-instanton background. We conjecture that the low-energy effective action of the IIB matrix model at large N is given by tree-level supergravity coupled to the vertex operators.
Transverse Vector Vertex Function and Transverse Ward-Takahashi Relations in QED
HE Han-Xin
2006-01-01
The transverse vector vertex function in momentum space in four-dimensional QED is derived in terms of a set of transverse Ward-Takahashi relations for the vector and the axial-vector vertices in the case of massless fermion.It is demonstrated explicitly that the transverse vector vertex function derived this way to one-loop order leads to the same result as one obtained in perturbation theory. This provides a basic approach to determine the transverse part of basic vertex function from the symmetry relations of the system.
The silicon vertex detector of the Belle II experiment
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.
The upgrade of the LHCb Vertex Locator (VELO)
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...
A dynamic cellular vertex model of growing epithelial tissues
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.
CDF Run II Silicon Vertex Detector Annealing Study
Stancari, M; Behari, S; Christian, D; Di Ruzza, B; Jindariani, S; Junk, T R; Mattson, M; Mitra, A; Mondragon, M N; Sukhanov, A
2013-01-01
Between Run II commissioning in early 2001 and the end of operations in September 2011, the Tevatron collider delivered 12~fb$^{-1}$ of $p\\bar{p}$ collisions at $\\sqrt{s}=1.96$ TeV to the Collider Detector at Fermilab (CDF). During that time, the CDF silicon vertex detector was subject to radiation doses of up to 12 Mrad. After the end of operations, the silicon detector was annealed for 24 days at $18^{\\circ}$C. In this paper, we present a measurement of the change in the bias currents for a subset of sensors during the annealing period. We also introduce a novel method for monitoring the depletion voltage throughout the annealing period. The observed bias current evolution can be characterized by a falling exponential term with time constant $\\tau_I=17.88\\pm0.36$(stat.)$\\pm0.25$(syst.) days. We observe an average decrease of $(27\\pm3)\\%$ in the depletion voltage, whose evolution can similarly be described by an exponential time constant of $\\tau_V=6.21\\pm0.21$ days. These results are consistent with the Ham...
CDF Run IIb Silicon Vertex Detector DAQ Upgrade
S. Behari et al.
2003-12-18
The CDF particle detector operates in the beamline of the Tevatron proton-antiproton collider at Fermilab, Batavia, IL. The Tevatron is expected to undergo luminosity upgrades (Run IIb) in the future, resulting in a higher number of interactions per beam crossing. To operate in this dense radiation environment, an upgrade of CDF's silicon vertex detector (SVX) subsystem and a corresponding upgrade of its VME-based DAQ system has been explored. Prototypes of all the Run IIb SVX DAQ components have been constructed, assembled into a test stand and operated successfully using an adapted version of CDF's network-capable DAQ software. In addition, a PCI-based DAQ system has been developed as a fast and inexpensive tool for silicon detector and DAQ component testing in the production phase. In this paper they present an overview of the Run IIb silicon DAQ upgrade, emphasizing the new features and improvements incorporated into the constituent VME boards, and discuss a PCI-based DAQ system developed to facilitate production tests.
From vertex detectors to inner trackers with CMOS pixel sensors
Besson, A.; Pérez, A. Pérez; Spiriti, E.; Baudot, J.; Claus, G.; Goffe, M.; Winter, M.
2017-02-01
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.
Automatised Data Quality Monitoring of the LHCb Vertex Locator
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...
19-vertex version of the fully frustrated XY model
Knops, Yolanda M. M.; Nienhuis, Bernard; Knops, Hubert J. F.; Blöte, Henk W. J.
1994-07-01
We investigate a 19-vertex version of the two-dimensional fully frustrated XY (FFXY) model. We construct Yang-Baxter equations for this model and show that there is no solution. Therefore we have chosen a numerical approach based on the transfer matrix. The results show that a coupled XY Ising model is in the same universality class as the FFXY model. We find that the phase coupling over an Ising wall is irrelevant at criticality. This leads to a correction of earlier determinations of the dimension x*h,Is of the Ising disorder operator. We find x*h,Is=0.123(5) and a conformal anomaly c=1.55(5). These results are consistent with the hypothesis that the FFXY model behaves as a superposition of an Ising model and an XY model. However, the dimensions associated with the energy, xt=0.77(3), and with the XY magnetization xh,XY~=0.17, refute this hypothesis.
Performance of the Aleph Upgraded Silicon Vertex Detector
Creanza, D.; De Palma, M.; Girone, M.; Maggi, G.; Selvaggi, G.; Silvestris, L.; Raso, G.; Tempesta, P.; Burns, M.; Coyle, P.; Engster, C.; Frank, M.; Moneta, L.; Wachnik, M.; Wagner, A.; Zaslavsky, J.; Focardi, E.; Sguazzoni, G.; Parrini, G.; Scarlini, E.; Halley, A.; O`Shea, V.; Raine, C.; Barber, G.; Cameron, W.; Dornan, P.; Gentry, D.; Konstantinidis, N.; Moutoussi, A.; Nash, J.; Price, D.; Stacey, A.; Toudup, L.W.; Williams, M.I.; Billault, M.; Bonissent, A.; Bujosa, G.; Calvet, D.; Carr, J.; Diaconu, C.; Blanc, P.E.; Destelle, J.J.; Karst, P.; Payre, P.; Rousseau, D.; Thulasidas, M.; Dietl, H.; Moser, H.-G.; Settles, R.; Seywerd, H.; Waltermann, G.; Bettarini, S.; Bosi, F.; Dell`Orso, R.; Messineo, A.; Profeti, A.; Rizzo, G.; Verdini, P.G.; Walsh, J.; Bizzell, J.P.; Maley, P.D.; Thompson, J.C.; Wright, A.E.; Black, S.; Kim, H.Y.; Bosisio, L.; Putz, J.; Rothberg, J.; Wasserbaech, S.; Elmer, P. [Bari Univ. (Italy). Dipt. di Fisica]|[INFN, Bari (Italy)]|[European Laboratory for Particle Physics (CERN), 1211 Geneva 23 (Switzerland)]|[Dipartimento di Fisica, Universita di Firenze, INFN Sezione di Firenze, 50125 Firenze (Italy)]|[Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)]|[Department of Physics, Imperial College, London SW7 2BZ (United Kingdom)]|[Department of Physics, University of Lancaster, Lancaster LA1 4YB (United Kingdom)]|[Centre de Physique des Particules, Faculte des Sciences de Luminy, IN2P3-CNRS, 13288 Marseille (France)]|[Max-Planck-Institut fuer Physik, Werner-Heisenberg-Institut, 80805 Muenchen (Germany)]|[Dipartimento di Fisica dell`Universita e INFN Sezione di Pisa, 56010 Pisa (Italy)]|[Particle Physics Dept., Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom)]|[Institute for Particle Physics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States)
1997-03-01
The ALEPH Vertex Detector (VDET) has been upgraded for the second phase of LEP running. The new version still uses double sided silicon strip detectors, fabricated with the same technology as the previous one, but the upgraded one is twice as long and has about half passive material in the tracking volume. Furthermore the readout electronics is now radiation hard (MX7-RH chips). An almost complete version of the upgraded VDET was installed in ALEPH during a three week LEP technical stop and took data in November 1995 during the LEP run at 130 GeV. The new detector worked well showing high signal over noise ratio and good efficiency. The point resolution measured during this run, using high momentum muons, 13 {mu}m in the r-{phi} view and 21 {mu}m in the r-z view, is dominated by the alignment precision, due to the low statistics available for this short LEP run. This result is however acceptable, since for lower momentum charged particle, the multiple scattering gives a significant contribution to the final impact parameter resolution. A better resolution has been achieved in the next run, when an initial period at the Z peak has been foreseen to calibrate and align the whole detector. (orig.).
CDF Run IIb Silicon Vertex Detector DAQ Upgrade
S. Behari et al.
2003-12-18
The CDF particle detector operates in the beamline of the Tevatron proton-antiproton collider at Fermilab, Batavia, IL. The Tevatron is expected to undergo luminosity upgrades (Run IIb) in the future, resulting in a higher number of interactions per beam crossing. To operate in this dense radiation environment, an upgrade of CDF's silicon vertex detector (SVX) subsystem and a corresponding upgrade of its VME-based DAQ system has been explored. Prototypes of all the Run IIb SVX DAQ components have been constructed, assembled into a test stand and operated successfully using an adapted version of CDF's network-capable DAQ software. In addition, a PCI-based DAQ system has been developed as a fast and inexpensive tool for silicon detector and DAQ component testing in the production phase. In this paper they present an overview of the Run IIb silicon DAQ upgrade, emphasizing the new features and improvements incorporated into the constituent VME boards, and discuss a PCI-based DAQ system developed to facilitate production tests.
Performance of the ALEPH upgraded silicon vertex detector
Creanza, D; Girone, M.; Maggi, G.; Selvaggi, G.; Silvestris, L.; Raso, G.; Tempesta, P.; Burns, M.; Coyle, P.; Engster, C.; Frank, M.; Moneta, L.; Wachnik, M.; Wagner, A.; Zaslavsky, J.; Focardi, E.; Sguazzoni, G.; Parrini, G.; Scarlini, E.; Halley, A.; O'Shea, V.; Raine, C.; Barber, G.; Cameron, W.; Dornan, P.; Gentry, D.; Konstantinidis, N.; Moutoussi, A.; Nash, J.; Price, D.; Stacey, A.; Toudup, L.W.; Williams, M.I.; Billault, M.; Bonissent, A.; Bujosa, G.; Calvet, D.; Carr, J.; Diaconu, C.; Blanc, P.E.; Destelle, J.J.; Karst, P.; Payre, P.; Rousseau, D.; Thulasidas, M.; Dietl, H.; Moser, H.G.; Settles, R.; Seywerd, H.; Waltermann, G.; Bettarini, S.; Bosi, F.; Dell'Orso, R.; Messineo, A.; Profeti, A.; Rizzo, G.; Verdini, P.G.; Walsh, J.; Bizzell, J.P.; Maley, P.D.; Thompson, J.C.; Wright, A.E.; Black, S.; Kim, H.Y.; Bosisio, L.; Putz, J.; Rothberg, J.; Wasserbaech, S.; Elmer, P.
1997-01-01
The ALEPH Vertex Detector (VDET) has been upgraded for the second phase of LEP running. The new version still uses double sided silicon strip detectors, fabricated with the same technology as the previous one, but the upgraded one is twice as long and has about half passive material in the tracking volume. Furthermore the readout electronics is now radiation hard (MX7-RH chips). An almost complete version of the upgraded VDET was installed in ALEPH during a three week LEP technical stop and took data in November 1995 during the LEP run at 130 GeV. The new detector worked well showing high signal over noise ratio and good efficiency. The point resolution measured during this run, using high momentum muons, 13 μm in the τ - φ view and 21 μm in the τ - z view, is dominated by the alignment precision, due to the low statistics available for this short LEP run. This result is however acceptable, since for lower momentum charged particle, the multiple scattering gives a significant contribution to the final im...
On the complexity of the balanced vertex ordering problem
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.
Towards Petaflops Capability of the VERTEX Supernova Code
Marek, Andreas; Hanke, Florian; Janka, Hans-Thomas
2014-01-01
The VERTEX code is employed for multi-dimensional neutrino-radiation hydrodynamics simulations of core-collapse supernova explosions from first principles. The code is considered state-of-the-art in supernova research and it has been used for modeling for more than a decade, resulting in numerous scientific publications. The computational performance of the code, which is currently deployed on several high-performance computing (HPC) systems up to the Tier-0 class (e.g. in the framework of the European PRACE initiative and the German GAUSS program), however, has so far not been extensively documented. This paper presents a high-level overview of the relevant algorithms and parallelization strategies and outlines the technical challenges and achievements encountered along the evolution of the code from the gigaflops scale with the first, serial simulations in 2000, up to almost petaflops capabilities, as demonstrated lately on the SuperMUC system of the Leibniz Supercomputing Centre (LRZ). In particular, we sh...
A neural network z-vertex trigger for Belle II
Neuhaus, Sara; Skambraks, Sebastian; Chen, Yang [Technische Universitaet Muenchen (Germany); Abudinen, Fernando; Kiesling, Christian [Max-Planck-Institut fuer Physik, Muenchen (Germany); Collaboration: Belle II-Collaboration
2015-07-01
In the Belle II experiment the efficiency of the track trigger could be increased by reconstructing the z-coordinate of track vertices at the first trigger level and rejecting tracks not coming from the interaction region, which form a large part of the machine background. The presented method employs neural networks to estimate the z-vertex without explicit track reconstruction. Input data is taken from the central drift chamber, using both the wire coordinates and the drift times for each hit. Neural networks are general function approximators that can learn nonlinear dependencies from real data without the need of an explicit model. However, using a priori knowledge about the track in a meaningful way can help to train more efficient networks, in terms of both prediction quality and network size. Such input information is provided by the Belle II 2D track trigger and is used explicitly in the calculation of the input values for the neural network. The algorithms for the input representation are presented together with estimations for the trigger efficiency and the rejection capability.
Metric Extension Operators, Vertex Sparsifiers and Lipschitz Extendability
Makarychev, Konstantin
2010-01-01
We study vertex cut and flow sparsifiers that were recently introduced by Moitra, and Leighton and Moitra. We improve and generalize their results. We give a new polynomial-time algorithm for constructing O(log k / log log k) cut and flow sparsifiers, matching the best existential upper bound on the quality of a sparsifier, and improving the previous algorithmic upper bound of O(log^2 k / log log k). We show that flow sparsifiers can be obtained from linear operators approximating minimum metric extensions. We introduce the notion of (linear) metric extension operators, prove that they exist, and give an exact polynomial-time algorithm for finding optimal operators. We then establish a direct connection between flow and cut sparsifiers and Lipschitz extendability of maps in Banach spaces, a notion studied in functional analysis since 1950s. Using this connection, we prove a lower bound of \\Omega(\\sqrt{log k/log log k}) for flow sparsifiers and a lower bound of \\Omega(\\sqrt[4]{log k/log log k}) for cut sparsif...
Jet Vertex Charge Reconstruction Poster for LHCP 2015
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...
A DEPFET pixel system for the ILC vertex detector
Trimpl, M; Kohrs, R; Krüger, H; Lodomez, P; Reuen, L; Sandow, C; Toerne, E; Velthuis, J J; Wermes, N; Andricek, L; Moser, H G; Richter, R H; Lutz, Gerhard; Giesen, F; Fischer, P; Peric, I
2006-01-01
We have developed a prototype system for the ILC vertex detector based on DEPFET pixels. The system operates a 128x64 pixel matrix and uses two dedicated microchips, the SWITCHER II chip for matrix steering and the CURO II chip for readout. The system development has been driven by the final ILC requirements which above all demand a detector thinned to 50 micron and a row wise read out with line rates of 20MHz and more. The targeted noise performance for the DEPFET technology is in the range of ENC=100e-. The functionality of the system has been demonstrated using different radioactive sources in an energy range from 6keV to 60keV. In recent test beam experiments using 6GeV electrons, a signal-to-noise ratio of S/N~120 has been achieved with present sensors being 450 micron thick. For improved DEPFET systems using 50 micron thin sensors in future, a signal-to-noise of 40 is expected.
Novel integrated CMOS pixel structures for vertex detectors
Kleinfelder, Stuart; Bieser, Fred; Chen, Yandong; Gareus, Robin; Matis, Howard S.; Oldenburg, Markus; Retiere, Fabrice; Ritter, Hans Georg; Wieman, Howard H.; Yamamoto, Eugene
2003-10-29
Novel CMOS active pixel structures for vertex detector applications have been designed and tested. The overriding goal of this work is to increase the signal to noise ratio of the sensors and readout circuits. A large-area native epitaxial silicon photogate was designed with the aim of increasing the charge collected per struck pixel and to reduce charge diffusion to neighboring pixels. The photogate then transfers the charge to a low capacitance readout node to maintain a high charge to voltage conversion gain. Two techniques for noise reduction are also presented. The first is a per-pixel kT/C noise reduction circuit that produces results similar to traditional correlated double sampling (CDS). It has the advantage of requiring only one read, as compared to two for CDS, and no external storage or subtraction is needed. The technique reduced input-referred temporal noise by a factor of 2.5, to 12.8 e{sup -}. Finally, a column-level active reset technique is explored that suppresses kT/C noise during pixel reset. In tests, noise was reduced by a factor of 7.6 times, to an estimated 5.1 e{sup -} input-referred noise. The technique also dramatically reduces fixed pattern (pedestal) noise, by up to a factor of 21 in our tests. The latter feature may possibly reduce pixel-by-pixel pedestal differences to levels low enough to permit sparse data scan without per-pixel offset corrections.
Error handling for the CDF Silicon Vertex Tracker
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 ...
Error handling for the CDF online silicon vertex tracker
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).
A dynamic cellular vertex model of growing epithelial tissues
Lin, Shao-Zhen; Li, Bo; Feng, Xi-Qiao
2017-03-01
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.
From vertex detectors to inner trackers with CMOS pixel sensors
Besson, A; Spiriti, E.; Baudot, J.; Claus, G.; Goffe, M.; Winter, M.
2016-01-01
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.
The quark-gluon vertex in Landau gauge bound-state studies
Williams, Richard
2015-05-01
We present a practical method for the solution of the quark-gluon vertex for use in Bethe-Salpeter and Dyson-Schwinger calculations. The efficient decomposition into the necessary covariants is detailed, with the numerical algorithm outlined for both real and complex Euclidean momenta. A truncation of the quark-gluon vertex, that neglects explicit back-coupling to enable the application to bound-state calculations, is given together with results for the quark propagator and quark-gluon vertex for different quark flavours. The relative impact of the various components of the quark-gluon vertex is highlighted with the flavour dependence of the effective quark-gluon interaction obtained, thus providing insight for the construction of phenomenological models within the rainbow ladder. Finally, we solve the corresponding Green's functions for complex Euclidean momenta as required in future bound-state calculations.
Lattice Landau gauge quark propagator and the quark-gluon vertex
Oliveira, Orlando; Silva, Paulo J; Skullerud, Jon-Ivar; Sternbeck, Andre; Williams, Anthony G
2016-01-01
We report preliminary results of our ongoing lattice computation of the Landau gauge quark propagator and the soft gluon limit of the quark-gluon vertex with 2 flavors of dynamical O(a) improved Wilson fermions.
Asymmetric 6-vertex model and classical Ruijsenaars-Schneider system of particles
Liashyk, A; Zabrodin, A; Zotov, A
2016-01-01
We discuss the correspondence between models solved by Bethe ansatz and classical integrable systems of Calogero type. We illustrate the correspondence by the simplest example of the inhomogeneous asymmetric 6-vertex model parametrized by trigonometric (hyperbolic) functions.
Experimental study of heat generation at the vertex of a fatigue crack
Terekhina, A. I.; Bannikov, M. V.; Plekhov, O. A.; Plekhova, E. V.
2012-08-01
The process of heat generation at the vertex of a fatigue crack in VT-6 titanium alloy under conditions of cyclic loading has been studied by infrared thermography. The spatial and temporal variations of temperature at the crack vertex have been measured, the shape of the zone of heat evolution has been determined, and the intensity of heat generation has been evaluated. Comparison of the obtained experimental data to the relations of the linear theory of elasticity shows that neither the observed shape of the plastic deformation zone nor the measured dynamics of heat evolution at the crack vertex is consistent with predictions of the linear theoretical models. The experimental results revealed a time delay between the moments of maximum applied stress and maximum intensity of heat evolution at the vertex of a fatigue crack.
A spin-foam vertex amplitude with the correct semiclassical limit
Engle, Jonathan
2012-01-01
Spin-foam models are hoped to provide a dynamics for loop quantum gravity. All 4-d spin-foam models of gravity start from the Plebanski formulation, in which gravity is recovered from a topological field theory, BF theory, by the imposition of constraints, which, however, select not only the gravitational sector, but also unphysical sectors. We show that this is the root cause for terms beyond the required Feynman-prescribed exponential of i times the action in the semiclassical limit of the EPRL spin-foam vertex. By quantizing a condition isolating the gravitational sector, we modify the EPRL vertex, yielding what we call the proper EPRL vertex amplitude. This provides at last a vertex amplitude for loop quantum gravity with the correct semiclassical limit.
The quark-gluon vertex in Landau gauge bound-state studies
Williams, Richard [Justus-Liebig University of Giessen, Institute of Theoretical Physics, Giessen (Germany)
2015-05-15
We present a practical method for the solution of the quark-gluon vertex for use in Bethe-Salpeter and Dyson-Schwinger calculations. The efficient decomposition into the necessary covariants is detailed, with the numerical algorithm outlined for both real and complex Euclidean momenta. A truncation of the quark-gluon vertex, that neglects explicit back-coupling to enable the application to bound-state calculations, is given together with results for the quark propagator and quark-gluon vertex for different quark flavours. The relative impact of the various components of the quark-gluon vertex is highlighted with the flavour dependence of the effective quark-gluon interaction obtained, thus providing insight for the construction of phenomenological models within the rainbow ladder. Finally, we solve the corresponding Green's functions for complex Euclidean momenta as required in future bound-state calculations. (orig.)
Calculating the vertex unknowns of nine point scheme on quadrilateral meshes for diffusion equation
YUAN GuangWei; SHENG ZhiQiang
2008-01-01
In the construction of nine point scheme, both vertex unknowns and cell-centered unknowns are introduced, and the vertex unknowns are usually eliminated by using the interpolation of neighboring cell-centered unknowns, which often leads to lose accuracy. Instead of using interpolation,here we propose a different method of calculating the vertex unknowns of nine point scheme, which are solved independently on a new generated mesh. This new mesh is a Voronoi mesh based on the vertexes of primary mesh and some additional points on the interface. The advantage of this method is that it is particularly suitable for solving diffusion problems with discontinuous coefficients on highly distorted meshes, and it leads to a symmetric positive definite matrix. We prove that the method has first-order convergence on distorted meshes. Numerical experiments show that the method obtains nearly second-order accuracy on distorted meshes.
Non-Abelian Ball-Chiu vertex for arbitrary Euclidean momenta
Aguilar, A C; Ferreira, M N; Papavassiliou, J
2016-01-01
We determine the non-Abelian version of the four longitudinal form factors of the quark-gluon vertex, using exact expressions derived from the Slavnov-Taylor identity that this vertex satisfies. In addition to the quark and ghost propagators, a key ingredient of the present approach is the quark-ghost scattering kernel, which is computed within the one-loop dressed approximation. The vertex form factors obtained from this procedure are evaluated for arbitrary Euclidean momenta, and display features not captured by the well-known Ball-Chiu vertex, deduced from the Abelian (ghost-free) Ward identity. The potential phenomenological impact of these results is evaluated through the study of special renormalization-point-independent combinations, which quantify the strength of the interaction kernels appearing in the standard quark gap and Bethe-Salpeter equations.
Explicit Exact Formulas for the 3-D Tetrahedron Inertia Tensor in Terms of its Vertex Coordinates
F. Tonon
2005-01-01
Full Text Available The inertia tensor of a tetrahedron is composed of its moments of inertia. This study presents explicit exact formulas for the moments of inertia of a 3-D tetrahedron as simple polynomials of its vertex coordinates.
Calculating the vertex unknowns of nine point scheme on quadrilateral meshes for diffusion equation
2008-01-01
In the construction of nine point scheme,both vertex unknowns and cell-centered unknowns are introduced,and the vertex unknowns are usually eliminated by using the interpolation of neighboring cell-centered unknowns,which often leads to lose accuracy.Instead of using interpolation,here we propose a different method of calculating the vertex unknowns of nine point scheme,which are solved independently on a new generated mesh.This new mesh is a Vorono¨i mesh based on the vertexes of primary mesh and some additional points on the interface.The advantage of this method is that it is particularly suitable for solving diffusion problems with discontinuous coeffcients on highly distorted meshes,and it leads to a symmetric positive definite matrix.We prove that the method has first-order convergence on distorted meshes.Numerical experiments show that the method obtains nearly second-order accuracy on distorted meshes.
LHCb Vertex Locator: Performance and radiation damage in LHC Run 1 and preparation for Run 2
Szumlak, T.; Obła˛kowska-Mucha, A.
2016-07-01
LHCb is a dedicated experiment to study New Physics in the decays of heavy hadrons at the Large Hadron Collider (LHC) at CERN. Heavy hadrons are identified through their flight distance in the Vertex Locator (VELO). The VELO comprises 42 modules made of two n+-on-n 300 μm thick half-disc silicon sensors with R- and Φ-measuring micro-strips. In order to allow retracting the detector, the VELO is installed as two movable halves containing 21 modules each. The detectors are operated in a secondary vacuum and are cooled by a bi-phase CO2 cooling system. During data taking in LHC Run 1 the LHCb VELO has operated with an extremely high efficiency and excellent performance. The track finding efficiency is typically greater than 98%. An impact parameter resolution of less than 35 μm 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 received a large and non-uniform radiation dose of up to 1.2 ×1014 1 MeV neutron equivalent cm-2 during the first LHC run. Silicon type-inversion has been observed in regions close to the interaction point. The preparations for LHC Run 2 are well under way and the VELO has already recorded tracks from injection line tests. The current status and plans for new operational procedures addressing the non-uniform radiation damage are shortly discussed.
Lisovyi, Mykhailo
2011-10-15
A measurement of charm production in deep inelastic scattering at {radical}(s)=318 GeV at HERA is presented in this thesis. The analysed data were collected with the ZEUS detector during 2005-2007, corresponding to the integrated luminosity of 323 pb{sup -1}. Charm production events were identified by the reconstruction of D{sup {+-}} mesons in the D{sup {+-}}{yields}K{sup -+}{pi}{sup {+-}}{pi}{sup {+-}} decay channel. The phase space of the analysis is defined by 5ZEUS measurements. The charm contribution to the proton structure function F{sub 2}, F{sub c}{sup 2}, was extracted. (orig.)
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{sup 2}, y, p{sub t}(D*) and {eta}(D*) have been measured at low Q{sup 2}. The data sample used was collected during the period 1998-2000 and amounts to an integrated luminosity of 82.2 pb{sup -1}. The low Q{sup 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 < Q{sup 2} < 0.7 GeV{sup 2} and 0.02 < y < 0.85. The D* mesons have been identified via the decay into lighter mesons D{sup *}+{yields}K{sup -}{pi}{sup +}{pi}{sup -} and the charged conjugated decay in the kinematic region 1.5
ZEUS D* production measurements could be extended towards lower values of Q{sup 2} in agreement with the corresponding perturbative QCD predictions. (orig.)
Twist Field as Three String Interaction Vertex in Light Cone String Field Theory
Kishimoto, Isao; Moriyama, Sanefumi; Teraguchi, Shunsuke
2006-01-01
It has been suggested that matrix string theory and light-cone string field theory are closely related. In this paper, we investigate the relation between the twist field, which represents string interactions in matrix string theory, and the three-string interaction vertex in light-cone string field theory carefully. We find that the three-string interaction vertex can reproduce some of the most important OPEs satisfied by the twist field.
Gornushkin, Yu. A.; Dmitrievsky, S. G.; Chukanov, A. V.
2015-01-01
The OPERA experiment is designed for the direct observation of the appearance of ντ from νμ → ντ oscillation in a νμ beam. A description of the procedure of neutrino interaction vertex localization (Brick Finding) by electronic detectors of a hybrid OPERA setup is presented. The procedure includes muon track and hadronic shower axis reconstruction and a determination of the target bricks with the highest probability to contain the vertex.
Precise Numerical Results of IR-vertex and box integration with Extrapolation Method
Yuasa, F; Fujimoro, J; Hamaguchi, N; Ishikawa, T; Shimizu, Y
2007-01-01
We present a new approach for obtaining very precise integration results for infrared vertex and box diagrams, where the integration is carried out directly without performing any analytic integration of Feynman parameters. Using an appropriate numerical integration routine with an extrapolation method, together with a multi-precision library, we have obtained integration results which agree with the analytic results to 10 digits even for such a very small photon mass as $10^{-150}$ GeV in the infrared vertex diagram.
NLO vertex for a forward jet plus a rapidity gap at high energies
Hentschinski, Martin; Madrigal Martínez, José Daniel; Murdaca, Beatrice; Vera, Agustín Sabio
2015-04-01
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).
Wake fields in the LHCb vertex detector : alternative designs for the wake field suppressor
Van Bakel, N; Ferro-Luzzi, M
2000-01-01
Two previous LHCb notes showed that wake field suppressors are needed to prevent dissipating excessive power in resonating modes of the vertex detector components. This note concentrates on two different designs of the encapsulations of the silicon detectors which can serve as an alternative to the design which uses long thin strips spanned throughout the vertex detector near the beam axis. The quality of wake field suppression with respect to the depth of a corrugated structure is simulated.
NLO Vertex for a Forward Jet plus a Rapidity Gap at High Energies
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).
Twist Field as Three String Interaction Vertex in Light Cone String Field Theory
Kishimoto, Isao; Moriyama, Sanefumi; Teraguchi, Shunsuke
2006-01-01
It has been suggested that matrix string theory and light-cone string field theory are closely related. In this paper, we investigate the relation between the twist field, which represents string interactions in matrix string theory, and the three-string interaction vertex in light-cone string field theory carefully. We find that the three-string interaction vertex can reproduce some of the most important OPEs satisfied by the twist field.
Tracking and Vertexing with the ATLAS Inner Detector in the LHC Run-2
Choi, Kyungeon; The ATLAS collaboration
2017-01-01
Run-2 of the Large Hadron Collider (LHC) has provided new challenges to track and vertex reconstruction with higher centre-of-mass energies and luminosity leading to increasingly high-multiplicity envi- ronments, boosted, and highly-collimated physics objects. We present an overview of the ATLAS Inner Detector tracker in Run-2 including the track reconstruction algorithm, time-dependent alignment, tracking and vertexing performance.
DFT Predictions on Structures and Stabilities of Eleven-vertex nido-and cioso-Heteroboranes
LI Ping
2009-01-01
Based on the octadecahedron of eleven-vertex closo-borane,the eleven-vertex closo-heteroborane was suggested with nonmetallic atoms instead of the different nonequivalent boron,and the stabilities were predicted at G96PW91/6-31+G(3d,2p) level.The small heteroatoms,C,N,O,preferentially occupy vertex 2 with the absolutely lowest relative energy to form the high stabilization closo-heteroboranes.They cap four-membered rings to satisfy the geometrical demand of short B-Z bonds.The electron attractions from the vicinal boron atoms make the frameworks shrink.Differently,Si and Ge preferentially substitute for boron at vertex 1 with six tight B-Z bonds and form stabilized molecules.P,As,S,and Se tend to occupy vertex 4 and the optimized structures belong to the nido configurations,in contrast to high electronegative heteroatoms,S and Se transfer less negative charges to framework and the electropositive heteroatoms,Si and Ge transfer more negative charges to framework to form the delocalization structures.The HOMO-LUMO gaps show that most of predicted clusters possess chemical stabilities.The substitutions of heteroatoms for boron atoms in eleven-vertex closo-hcteroboranes are consistent with the topological charge stabilization rule proposed by Gimarc.
TECHNICAL DESIGN REPORT OF THE FORWARD SILICON VERTEX (FVTX)
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.
VERTEX: Manganese transport with CaCO 3
Martin, John H.; Knauer, George A.
1983-04-01
Manganese transport was studied off central California in August and September 1981 as part of the VERTEX (Vertica l Transport and Exchange) research program. Refractory, leachable, and dissolved Mn fractions associated with particles caught in traps set at 11 depths (50 to 2000 m) were analyzed. Through intentional and unintentional CaCO 3 dissolution 'experiments', it was learned that the weakly leachable Mn was originally in association with the carbonate phase. Adsorption on surfaces rather than absorption in CaCO 3 matrices was indicated by the finding that Mn was not released in proportion to the CaCo 3 dissolved, instead it appeared to keep readsorbing to the dissolving surface. Ultimately, Mn went into solution when the particulate CaCO 3 was essentially depleted, suggesting that sufficient sites for adsorption were no longer available. Manganese fluxes with CaCO 3 were low near the surface (0.1 mg cm -2 ky -1), but increased rapidly in the 50 to 200-m depth interval, and then became more or less constant (1.3 mg cm -2 ky -1 for the remainder of the water column (300 to 2000 m). Rate-of-change estimates indicate that Mn is rapidly scavenged in near-surface waters (-130 ng 1 -1 y -1) and slowly regenerated at depth (2.7 ng 1 -1 y -1) in our near-shore study area. Residence times for dissolved Mn were estimated at 1.2 y for surface waters and 17 y at depth. The implications of Mn transport with CaCO 3 in relation to open-ocean sediment excess Mn are discussed.
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...
A vertex model of Drosophila ventral furrow formation.
Philipp Spahn
Full Text Available Ventral furrow formation in Drosophila is an outstanding model system to study the mechanisms involved in large-scale tissue rearrangements. Ventral cells accumulate myosin at their apical sides and, while being tightly coupled to each other via apical adherens junctions, execute actomyosin contractions that lead to reduction of their apical cell surface. Thereby, a band of constricted cells along the ventral epithelium emerges which will form a tissue indentation along the ventral midline (the ventral furrow. Here we adopt a 2D vertex model to simulate ventral furrow formation in a surface view allowing easy comparison with confocal live-recordings. We show that in order to reproduce furrow morphology seen in vivo, a gradient of contractility must be assumed in the ventral epithelium which renders cells more contractile the closer they lie to the ventral midline. The model predicts previous experimental findings, such as the gain of eccentric morphology of constricting cells and an incremental fashion of apical cell area reduction. Analysis of the model suggests that this incremental area reduction is caused by the dynamical interplay of cell elasticity and stochastic contractility as well as by the opposing forces from contracting neighbour cells. We underpin results from the model through in vivo analysis of ventral furrow formation in wildtype and twi mutant embryos. Our results show that ventral furrow formation can be accomplished as a "tug-of-war" between stochastically contracting, mechanically coupled cells and may require less rigorous regulation than previously thought.For the developmental biologist it is a fascinating question how cells can coordinate major tissue movements during embryonic development. The so-called ventral furrow of the Drosophila embryo is a well-studied example of such a process when cells from a ventral band, spanning nearly the entire length of the embryo, undergo dramatic shape change by contracting their
Domain wall partition function of the eight-vertex model with a non-diagonal reflecting end
Yang, Wen-Li; Feng, Jun; Hao, Kun; Shi, Kang-Jie; Sun, Cheng-Yi; Yang, Zhan-Ying; Zhang, Yao-Zhong
2011-01-01
With the help of the Drinfeld twist or factorizing F-matrix for the eight-vertex SOS model, we obtain the explicit determinant expression of the partition function of the eight-vertex model with a generic non-diagonal reflecting end and domain wall boundary condition. Our result shows that, contrary to the eight-vertex model without a reflection end, the partition function can be expressed as a single determinant.
Laser Metrology in the Micro-Arcsecond Metrology Testbed
An, Xin; Marx, D.; Goullioud, Renaud; Zhao, Feng
2004-01-01
The Space Interferometer Mission (SIM), scheduled for launch in 2009, is a space-born visible light stellar interferometer capable of micro-arcsecond-level astrometry. The Micro-Arcsecond Metrology testbed (MAM) is the ground-based testbed that incorporates all the functionalities of SIM minus the telescope, for mission-enabling technology development and verification. MAM employs a laser heterodyne metrology system using the Sub-Aperture Vertex-to-Vertex (SAVV) concept. In this paper, we describe the development and modification of the SAVV metrology launchers and the metrology instrument electronics, precision alignments and pointing control, locating cyclic error sources in the MAM testbed and methods to mitigate the cyclic errors, as well as the performance under the MAM performance metrics.
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 eta'g sup * g sup ( sup * sup ) vertex including the eta'-meson mass
Ali, A
2003-01-01
The eta'g sup * g sup ( sup * sup ) effective vertex function is calculated in the QCD hard-scattering approach, taking into account the eta'-meson mass. We work in the approximation in which only one non-leading Gegenbauer moment for both the quark-antiquark and the gluonic light-cone distribution amplitudes for the eta'-meson is kept. The vertex function with one off-shell gluon is shown to have the form (valid for vertical stroke q sub 1 sup 2 vertical stroke >m subeta sub ' sup 2) F subeta sub ' sub g sub sup * sub g (q sub 1 sup 2 ,0,m subeta sub ' sup 2)=m subeta sub ' sup 2 H(q sub 1 sup 2)/(q sub 1 sup 2 -m subeta sub ' sup 2), where H(q sub 1 sup 2) is a slowly varying function, derived analytically in this paper. The resulting vertex function is in agreement with the phenomenologically inferred form of this vertex obtained from an analysis of the CLEO data on the eta'-meson energy spectrum in the decay UPSILON(1S)-> eta'X. We also present an interpolating formula for the vertex function F subeta sub...
The $\\eta^{'} g^{*} g^{(*)}$ Vertex Including the $\\eta^{'}$-Meson Mass
Ali, A
2003-01-01
The $eta^prime g^* g^{(*)}$ effective vertex function is calculated in the QCD hard-scattering approach, taking into account the $eta^prime$-meson mass. We work in the approximation in which only one non-leading Gegenbauer moment for both the quark-antiquark and the gluonic light-cone distribution amplitudes for the $eta^prime$-meson is kept. The vertex function with one off-shell gluon is shown to have the form (valid for $| q_1^2 | > m_{eta^prime}^2$) $F_{eta^prime g^* g} (q_1^2, 0, m_{eta^prime}^2) = m_{eta^prime}^2 H(q_1^2)/(q_1^2 - m_{eta^prime}^2)$, where $H(q_1^2)$ is a slowly varying function, derived analytically in this paper. The resulting vertex function is in agreement with the phenomenologically inferred form of this vertex obtained from an analysis of the CLEO data on the $eta^prime$-meson energy spectrum in the decay $Upsilon(1S) to eta^prime X$. We also present an interpolating formula for the vertex function $F_{eta^prime g^* g} (q_1^2, 0, m_{eta^prime}^2)$ for the space-like region of the v...
Vertex ﬁnding performance studies for the Phase II CMS Level-1 Trigger
Udrescu, Silviu Marian
2017-01-01
At the HL-LHC, a signiﬁcant increase in the luminosity delivered to CMS will result in a pileup per bunch crossing of 140-200. This provides a diﬃcult environment to obtain reliable physics results and keep trigger rates manageable. In order to mitigate this problem, tracker information will be used, for the ﬁrst time, at the Level-1 (L1) trigger. This will allow the primary vertex reconstruction at L1. In this report, an investigation into the vertex ﬁnding performance of a potential algorithm is presented. The vertex ﬁnding eﬃciency was measured as a function of several variables, such as the percentage of tracks associated to the primary vertex within the barrel and the pT of the tracks. The eﬃciency was found to not depend signiﬁcantly on the pileup for the samples analyzed, however, a strong dependence was observed on the number of tracks associated with the primary vertex.
Wlasenko, Michal
2009-05-15
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{sup -1}, are presented. The single-differential cross sections d{sigma}/dQ{sup 2}, d{sigma}/dx, d{sigma}/dy and the double-differential reduced cross section {sigma} were measured in the kinematic region of 185
Derrick, Malcolm; Magill, S; Mikunas, D; Musgrave, B; Repond, J; Stanek, R; Talaga, R L; Zhang, H; Ayad, R; Bari, G; Basile, M; Bellagamba, L; Boscherini, D; Bruni, A; Bruni, G; Bruni, P; Cara Romeo, G; Castellini, G; Chiarini, M; Cifarelli, Luisa; Cindolo, F; Contin, A; Corradi, M; Gialas, I; Giusti, P; Iacobucci, G; Laurenti, G; Levi, G; Margotti, A; Massam, Thomas; Nania, R; Nemoz, C; Palmonari, F; Polini, A; Sartorelli, G; Timellini, R; Zamora-Garcia, Yu E; Zichichi, Antonino; Bargende, A; Crittenden, James Arthur; Desch, Klaus; Diekmann, B; Doeker, T; Eckert, M; Feld, L; Frey, A; Geerts, M; Geitz, G; Grothe, M; Haas, T; Hartmann, H; Haun, D; Heinloth, K; Hilger, E; Jakob, H P; Katz, U F; Mari, S M; Mass, A; Mengel, S; Mollen, J; Paul, E; Rembser, C; Schattevoy, R; Schramm, D; Stamm, J; Wedemeyer, R; Campbell-Robson, S; Cassidy, A; Dyce, N; Foster, B; George, S; Gilmore, R; Heath, G P; Heath, H F; Llewellyn, T J; Morgado, C J S; Norman, D J P; O'Mara, J A; Tapper, R J; Wilson, S S; Yoshida, R; Rau, R R; Arneodo, M; Iannotti, L; Schioppa, M; Susinno, G; Bernstein, A M; Caldwell, A; Cartiglia, N; Parsons, J A; Ritz, S; Sciulli, F; Straub, P B; Wai, L; Yang, S; Zhu, Q; Borzemski, P; Chwastowski, J; Eskreys, Andrzej; Piotrzkowski, K; Zachara, M; Zawiejski, L; Adamczyk, L; Bednarek, B; Jelen, K; Kisielewska, D; Kowalski, T; Rulikowska-Zarebska, E; Suszycki, L; Zajac, J; Kotanski, Andrzej; Przybycien, M B; Bauerdick, L A T; Behrens, U; Beier, H; Bienlein, J K; Coldewey, C; Deppe, O; Desler, K; Drews, G; Flasinski, M; Gilkinson, D J; Glasman, C; Göttlicher, P; Grosse-Knetter, J; Gutjahr, B; Hain, W; Hasell, D; Hessling, H; Iga, Y; Joos, P; Kasemann, M; Klanner, Robert; Koch, W; Köpke, L; Kötz, U; Kowalski, H; Labs, J; Ladage, A; Löhr, B; Loewe, M; Lüke, D; Manczak, O; Monteiro, T; Ng, J S T; Nickel, S; Notz, D; Ohrenberg, K; Roco, M T; Rohde, M; Roldán, J; Schneekloth, U; Schulz, W; Selonke, F; Stiliaris, E; Surrow, B; Voss, T; Westphal, D; Wolf, G; Youngman, C; Zhou, J F; Grabosch, H J; Kharchilava, A I; Leich, A; Mattingly, M C K; Meyer, A; Schlenstedt, S; Wulff, N; Barbagli, G; Pelfer, P G; Anzivino, Giuseppina; Maccarrone, G D; De Pasquale, S; Votano, L; Bamberger, Andreas; Eisenhardt, S; Freidhof, A; Söldner-Rembold, S; Schröder, J; Trefzger, T M; Brook, N H; Bussey, Peter J; Doyle, A T; Fleck, I; Saxon, D H; Utley, M L; Wilson, A S; Dannemann, A; Holm, U; Horstmann, D; Neumann, T; Sinkus, R; Wick, K; Badura, E; Burow, B D; Hagge, L; Lohrmann, E; Mainusch, J; Milewski, J; Nakahata, M; Pavel, N; Poelz, G; Schott, W; Zetsche, F; Bacon, Trevor C; Butterworth, Ian; Gallo, E; Harris, V L; Hung, B Y H; Long, K R; Miller, D B; Morawitz, P P O; Prinias, A; Sedgbeer, J K; Whitfield, A F; Mallik, U; McCliment, E; Wang, M Z; Wang, S M; Wu, J T; Zhang, Y; Cloth, P; Filges, D; An Shiz Hong; Hong, S M; Nam, S W; Park, S K; Suh, M H; Yon, S H; Imlay, R; Kartik, S; Kim, H J; McNeil, R R; Metcalf, W; Nadendla, V K; Barreiro, F; Cases, G; Graciani, R; Hernández, J M; Hervás, L; Labarga, L; Del Peso, J; Puga, J; Terrón, J; De Trocóniz, J F; Smith, G R; Corriveau, F; Hanna, D S; Hartmann, J; Hung, L W; Lim, J N; Matthews, C G; Patel, P M; Sinclair, L E; Stairs, D G; Saint-Laurent, M G; Ullmann, R T; Zacek, G; Bashkirov, V; Dolgoshein, B A; Stifutkin, A; Bashindzhagian, G L; Ermolov, P F; Gladilin, L K; Golubkov, Yu A; Kobrin, V D; Kuzmin, V A; Proskuryakov, A S; Savin, A A; Shcheglova, L M; Solomin, A N; Zotov, N P; Botje, M; Chlebana, F S; Dake, A P; Engelen, J; De Kamps, M; Kooijman, P M; Kruse, A; Tiecke, H G; Verkerke, W; Vreeswijk, M; Wiggers, L; De Wolf, E; Van Woudenberg, R; Acosta, D; Bylsma, B G; Durkin, L S; Honscheid, K; Li Chuan; Ling, T Y; McLean, K W; Murray, W N; Park, I H; Romanowsky, T A; Seidlein, R; Bailey, D S; Blair, G A; Byrne, A; Cashmore, Roger J; Cooper-Sarkar, A M; Daniels, D C; Devenish, R C E; Harnew, N; Lancaster, M; Luffman, P; Lindemann, L; McFall, J D; Nath, C; Noyes, V A; Quadt, A; Uijterwaal, H; Walczak, R; Wilson, F F; Yip, T; Abbiendi, G; Bertolin, A; Brugnera, R; Carlin, R; Dal Corso, F; De Giorgi, M; Dosselli, U; Limentani, S; Morandin, M; Posocco, M; Stanco, L; Stroili, R; Voci, C; Bulmahn, J; Butterworth, J M; Feild, R G; Oh, B Y; Whitmore, J; D'Agostini, Giulio; Marini, G; Nigro, A; Tassi, E; Hart, J C; McCubbin, N A; Prytz, K; Shah, T P; Short, T L; Barberis, E; Dubbs, T; Heusch, C A; Van Hook, M; Hubbard, B; Lockman, W; Rahn, J T; Sadrozinski, H F W; Seiden, A; Biltzinger, J; Seifert, R J; Walenta, Albert H; Zech, G; Abramowicz, H; Briskin, G M; Dagan, S; Levy, A; Hasegawa, T; Hazumi, M; Ishii, T; Kuze, M; Mine, S; Nagasawa, Y; Nakao, M; Susuki, I; Tokushuku, K; Yamada, S; Yamazaki, Y; Chiba, M; Hamatsu, R; Hirose, T; Homma, K; Kitamura, S; Nakamitsu, Y; Yamauchi, K; Cirio, R; Costa, M; Ferrero, M I; Lamberti, L; Maselli, S; Peroni, C; Sacchi, R; Solano, A; Staiano, A; Dardo, M; Bailey, D C; Bandyopadhyay, D; Bénard, F; Brkic, M; Crombie, M B; Gingrich, D M; Hartner, G F; Joo, K K; Levman, G M; Martin, J F; Orr, R S; Sampson, C R; Teuscher, R; Catterall, C D; Jones, T W; Kaziewicz, P B; Lane, J B; Saunders, R L; Shulman, J; Blankenship, K; Lu, B; Mo, L W; Bogusz, W; Charchula, K; Ciborowski, J; Gajewski, J; Grzelak, G; Kasprzak, M; Krzyzanowski, M; Muchorowski, K; Nowak, R J; Pawlak, J M; Tymieniecka, T; Wróblewski, A K; Zakrzewski, J A; Zarnecki, A F; Adamus, M; Eisenberg, Y; Karshon, U; Revel, D; Zer-Zion, D; Ali, I; Badgett, W F; Behrens, B H; Dasu, S; Fordham, C; Foudas, C; Goussiou, A; Loveless, R J; Reeder, D D; Silverstein, S; Smith, W H; Vaiciulis, A W; Wodarczyk, M; Tsurugai, T; Bhadra, S; Cardy, M L; Fagerstroem, C P; Frisken, W R; Furutani, K M; Khakzad, M; Schmidke, W B
1995-01-01
This paper reports the cross section measurements for the process ep \\rightarrow e~\\jpsi~p for Q^2 < 4 GeV^2 at \\sqrt s = 296 GeV, based on an integrated luminosity of about 0.5~pb^{-1}, using the ZEUS detector. The \\jpsi~was detected in its \\rm e^{+}e^{-} and \\rm \\mu^{+}\\mu^{-} decay modes. The photoproduction cross section was measured to be 52^{ \\ +7}_{-12}\\pm 10~nb at an average \\gammap centre of mass energy of 67 GeV and 71^{+13}_{-20}\\pm 12~nb at 114 GeV. The significant rise of the cross section compared to lower energy measurements is not in agreement with VDM models, but can be described by QCD inspired models if a rise in the gluon momentum density at low x in the proton is assumed.
The quark-gluon vertex in Landau gauge bound-state studies
Williams, Richard
2014-01-01
We present a practical method for the solution of the quark-gluon vertex for use in Bethe--Salpeter and Dyson--Schwinger calculations. The efficient decomposition into the necessary covariants is detailed, with the numerical algorithm outlined for both real and complex Euclidean momenta. A model suitable for bound-state calculations is given together with results for the quark propagator and quark-gluon vertex for different quark flavours. The relative impact of the various components of the quark-gluon vertex is highlighted with the flavour dependence of the effective quark-gluon interaction obtained, thus providing insight for the construction of phenomenological models within Rainbow-Ladder. Finally, we solve the corresponding Green's functions for complex Euclidean momenta as required for practical calculations.
Modeling & Informatics at Vertex Pharmaceuticals Incorporated: our philosophy for sustained impact
McGaughey, Georgia; Patrick Walters, W.
2016-11-01
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.
A new efficient RLF-like algorithm for the vertex coloring problem
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.
Measurement of the Charm and Beauty Structure Functions using the H1 Vertex Detector at HERA
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.
Vertex Corrections for Positive-Definite Spectral Functions of Simple Metals
Pavlyukh, Y.; Uimonen, A.-M.; Stefanucci, G.; van Leeuwen, R.
2016-11-01
We present a systematic study of vertex corrections in a homogeneous electron gas at metallic densities. The vertex diagrams are built using a recently proposed positive-definite diagrammatic expansion for the spectral function. The vertex function not only provides corrections to the well known plasmon and particle-hole scatterings, but also gives rise to new physical processes such as the generation of two plasmon excitations or the decay of the one-particle state into a two-particle-one-hole state. By an efficient Monte Carlo momentum integration we are able to show that the additional scattering channels are responsible for a reduction of the bandwidth, the appearance of a secondary plasmon satellite below the Fermi level, and a substantial redistribution of spectral weights. The feasibility of the approach for first-principles band-structure calculations is also discussed.
ATLAS strategy for primary vertex reconstruction during Run-2 of the LHC
Borissov, Guennadi; The ATLAS collaboration; Grimm, Kathryn; Pagan Griso, Simone; Pedersen, Lars Egholm; Prokofiev, Kirill; Rudolph, Matthew Scott; Wharton, Andrew Mark
2015-01-01
The reconstruction of vertices corresponding to proton--proton collisions in ATLAS is an essential element of event reconstruction used in many performance studies and physics analyses. During Run-1 of the LHC, ATLAS has employed an iterative approach to vertex finding. In order to improve the flexibility of the algorithm and ensure continued performance for very high numbers of simultaneous collisions in Run-2 of the LHC and beyond, a new approach to seeding vertex finding has been developed inspired by image reconstruction techniques. This note provides a brief outline of how reconstructed tracks are used to create an image of likely vertex collisions in an event, describes the implementation in the ATLAS software, and presents some preliminary results of the performance of the algorithm in simulation approximating early Run-2 conditions.
Measurement of the charm and beauty structure functions using the H1 vertex detector at HERA
Aaron, F.D.; Alexa, C.; Preda, T.; Rotaru, M.; Stoicea, G.; Zus, R. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); 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. [DESY, Hamburg (Germany); 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. [Lebedev Physical Institute, Moscow (Russian Federation); Asmone, A.; Stella, B. [Dipt. di Fisica Universita di Roma Tre (Italy); INFN Roma 3, Rome (Italy); Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N. [Univ. of Montenegro, Faculty of Science, Podgorica (ME); Baghdasaryan, A.; Ghazaryan, S.; Volchinski, V.; Zohrabyan, H. [Yerevan Physics Inst., Yerevan (Armenia); Barrelet, E. [CNRS/IN2P3, LPNHE, Universites Paris VI et VII, Paris (France); Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B. [Inst. of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar (Mongolia); Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Li, G.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F. [CNRS/IN2P3, LAL, Univ. Paris-Sud, Orsay (France); Boudry, V.; Moreau, F.; Specka, A. [CNRS/IN2P3, LLR, Ecole Polytechnique, Palaiseau (France)] [and others
2010-01-15
Inclusive charm and beauty cross sections are measured in e{sup -}p and e{sup +} p neutral current collisions at HERA in the kinematic region of photon virtuality 5{<=}Q {sup 2}{<=}2000 GeV{sup 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{sup -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.)
Measurement of the charm and beauty structure functions using the H1 vertex detector at HERA
Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Aldaya Martin, M. [DESY, Hamburg (Germany); Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (RO)] (and others)
2009-06-15
Inclusive charm and beauty cross sections are measured in e{sup -}p and e{sup +}p neutral current collisions at HERA in the kinematic region of photon virtuality 5{<=}Q{sup 2}{<=}2000 GeV{sup 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{sup -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.)
Exploring complex networks by means of two-variable time series of vertex observables
Oświȩcimka, Paweł; Drożdż, Stanisław
2016-01-01
We investigate the scaling of the cross-correlations calculated for two-variable time series containing vertex properties in the context of complex networks. Time series of such observables are obtained by means of stationary, unbiased random walks. We consider three vertex properties that provide, respectively, short, medium, and long-range information regarding the topological role of a vertex in a given network. We present and discuss results obtained on some well-known network models, as well as on real data representing protein contact networks. Our results suggest that the proposed analysis framework provides useful insights on the structural organization of complex networks. For instance, the analysis of protein contact networks reveals characteristics shared with both scale-free and small-world models.
The neural network Z vertex trigger for the Belle II detector
Skambraks, Sebastian; Abudinen, Fernando [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Foehringer Ring 6 80805 Muenchen (Germany)
2013-07-01
A novel approach for track triggering is currently studied for the Belle II detector: neural networks are used to predict the event vertex in z direction, using only information from the central drift chamber. The lack in accuracy of classical online vertex reconstruction motivates new studies for the z vertex trigger. Since neural networks are general function approximators, they are well suited for problems where the model is not known a priori. Several methods were investigated, but our studies for single tracks in geometrically restricted areas of the detector have proven the multi layer perceptron to produce the most accurate results, even in the presence of background. This encourages the use of a set of multi layer perceptrons to cover the entire detector. Additionally, the methods presented may lead to online event reconstruction, for Belle II as well as for other running or future detectors.
Modeling & Informatics at Vertex Pharmaceuticals Incorporated: our philosophy for sustained impact
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.
Performance of the ATLAS track and vertex reconstruction in the LHC Run 2
Oide, Hideyuki; The ATLAS collaboration
2016-01-01
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 and boosted, highly-collimated physics objects. The Insertable B-layer (IBL) is a fourth pixel layer, which was inserted in the innermost region of ATLAS during the long shutdown of the LHC. We will present results showing the performance of the track and vertex reconstruction algorithms using Run-2 data at the LHC and discuss some of the challenges encountered during commissioning. Recent improvements include a factor of three reduction in the reconstruction time, optimisation for the expected conditions, novel techniques to enhance the performance in dense jet cores and time-dependent alignment of sub-detectors. Moreover, data-driven methods to evaluate vertex resolution, fake rates, track reconstruction inefficiencies in dense environments, and track parameter resolution and biases will be shown.
Thermo-magnetic behavior of the of the quark-gluon vertex
Ayala, Alejandro; Loewe, M; Tejeda-Yeomans, Maria Elena; Zamora, R
2015-01-01
The thermo-magnetic corrections to the quark-gluon vertex in the presence of a weak magnetic field are calculated in the frame of the Hard Thermal Loop approximation. The vertex satisfies a QED-like Ward identity with the quark self-energy calculated within the same approximation. It turns out that only the longitudinal vertex components get modified. The calculation provides a first principles result for the quark anomalous magnetic moment at high temperature in a weak magnetic field. The effective thermo-magnetic quark-gluon coupling shows a decreasing behavior as function of the field strength. This result supports the observation that the behavior of the effective quark-gluon coupling in the presence of a magnetic field is an important ingredient in order to understand the inverse magnetic catalysis phenomenon recently observed in the lattice QCD simulations.
Status of vertex and tracking detector R&D at CLIC
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).
Constraint Minimum Vertex Cover in K-Partite Graph: Approximation Algorithm and Complexity Analysis
Kamanashis Biswas
2009-08-01
Full Text Available Generally, a graph G, an independent set is a subset S of vertices in G such that no two vertices in S are adjacent (connected by an edge and a vertex cover is a subset S of vertices such that each edge of G has at least one of its endpoints in S. Again, the minimum vertex cover problem is to find a vertex cover with the smallest number of vertices. Consider a k-partite graph G = (V, E with vertex k-partition V = P1 ∪ P2 . . . ∪ Pk and the k integers are kp1, kp2, . . . , kpk. And, we want to find out whether there is a minimum vertex cover in G with at most kp1 vertices in P1 and kp2 vertices in P2 and so on or not. This study shows that the constrained minimum vertex cover problem in k-partite graph (MIN-CVCK is NP-Complete which is an important property of k-partite graph. Many combinatorial problems on general graphs are NP-complete, but when restricted to k-partite graph with at most k vertices then many of these problems can be solved in polynomial time. This paper also illustrates an approximation algorithm for MIN-CVCK and analyzes its complexity. In future work section, we specified a number of dimensions which may be interesting for the researchers such as developing algorithm for maximum matching and polynomial algorithm for constructing k-partite graph from general graph.
Exchange Relations for the q-Vertex Operators of $U_q(\\widehat{sl2})$
Awata, H
1993-01-01
We consider the q-deformed Knizhnik-Zamolodchikov equation for the two point function of q-deformed vertex operators of $U_q(sl_2^)$. We give explicitly the fundamental solutions, the connection matrices and the exchange relations for the q-vertex operators of spin 1/2 and $j \\in {1\\over 2}{\\bf Z}_{\\geq 0}$. Consequently, we confirm that the connection matrices are equivalent to the elliptic Boltzman weights of IRF type obtained by the fusion procedure from ABF models.
Algebraic arctic curves in the domain-wall six-vertex model
Colomo, F
2010-01-01
The arctic curve, i.e. the spatial curve separating ordered (or `frozen') and disordered (or `temperate) regions, of the six-vertex model with domain wall boundary conditions is discussed for the root-of-unity vertex weights. In these cases the curve is described by algebraic equations which can be worked out explicitly from the parametric solution for this curve. Some interesting examples are discussed in detail. The upper bound on the maximal degree of the equation in a generic root-of-unity case is obtained.
Charged free fermions, vertex operators and the classical theory of conjugate nets
Doliwa, Adam [Istituto Nazionale di Fisica Nucleare, Sezione di Roma, Rome (Italy); Instytut Fizyki Teoretycznej, Uniwersytet Warszawski, Warsaw (Poland); Manas, Manuel [Departamento de Matematica Aplicada y Estadistica, EUIT Aeronautica, Universidad Politecnica de Madrid, Madrid (Spain); Departamento de Fisica Teorica, Universidad Complutense, Madrid (Spain); Martinez Alonso, Luis; Medina, Elena [Departamento de Matematicas, Universidad de Cadiz, Cadiz (Spain); Santini, Paolo Maria [Istituto Nazionale di Fisica Nucleare, Sezione di Roma, Rome (Italy); Dipartimento di Fisica, Universita di Catania, Catania (Italy)
1999-02-19
We show that the quantum field theoretical formulation of the {tau}-function theory has a geometrical interpretation within the classical transformation theory of conjugate nets. In particular, we prove that (i) the partial charge transformations preserving the neutral sector are Laplace transformations, (ii) the basic vertex operators are Levy and adjoint Levy transformations and (iii) the diagonal soliton vertex operators generate fundamental transformations. We also show that the bilinear identity for the multicomponent Kadomtsev-Petviashvili hierarchy becomes, through a generalized Miwa map, a bilinear identity for the multidimensional quadrilateral lattice equations. (author)
Donaldson-Thomas invariants of local elliptic surfaces via the topological vertex
Bryan, Jim
2016-01-01
We compute the Donaldson-Thomas invariants of a local elliptic surface with section. We introduce a new computational technique which is a mixture of motivic and toric methods. This allows us to write the partition function for the invariants in terms of the topological vertex. Utilizing identities for the topological vertex proved in arXiv:1603.05271, we derive product formulas for the partition functions. The connected version of the partition function is written in terms of Jacobi forms. In the special case where the elliptic surface is a K3 surface, we get a new derivation of the Katz-Klemm-Vafa formula.
Building a non-perturbative quark-gluon vertex from a perturbative one
Bermudez, Rocio
2016-10-01
The quark-gluon vertex describes the electromagnetic and the strong interaction among these particles. The description of this interaction at high precision in both regimes, perturbative and non-perturbative, continues being a matter of interest in the context of QCD and Hadron Physics. There exist very helpful models in the literature that explain perturbative aspects of the theory but they fail describing non-perturbative phenomena, as confinement and dynamic chiral symmetry breaking. In this work we study the structure of the quark-gluon vertex in a non-perturbative regime examining QCD, checking results with QED, and working in the Schwinger-Dyson formalism.
Effects of a dressed quark-gluon vertex in vector heavy-light mesons
Gomez-Rocha, M; Krassnigg, A
2016-01-01
We extend earlier investigations of heavy-light pseudoscalar mesons to the vector case, using a simple model in the context of the Dyson-Schwinger-Bethe-Salpeter approach. We investigate the effects of a dressed-quark-gluon vertex in a systematic fashion and illustrate and attempt to quantify corrections beyond the phenomenologically very useful and successful rainbow-ladder truncation. In particular we investigate dressed quark photon vertex in such a setup and make a prediction for the experimentally as yet unknown mass of the B_c*, which we obtain at 6.334 GeV well in line with predictions from other approaches.
Spontaneous Polarization of Kondo problem associated with Higher-spin analog of the 6-vertex model
Fukushima, N
1999-01-01
We study Kondo-type model associated with an integrable Higher-spin analog of the 6-vertex mode, which is constructed by inserting a spin 1/2 to spin 1 lines: $... C^3 \\otimes C^3 \\otimes C^2 \\otimes C^3 \\otimes C^3 ... .$ We formulate the problem in terms of representation theory of quantum affine algebra $U_q(\\hat{sl_2})$. We derive an exact formula of the spontaneous staggered polarization for our model, which corresponds to Baxter's formula for the 6-vertex model.
Imaging the LHC beams with silicon and scintillating fibre vertex detectors
Rihl, M.
2017-02-01
The LHCb Vertex Locator (VELO) is used to reconstruct beam-gas interaction vertices which allows one to obtain precise profiles of the LHC beams. In LHCb, this information is combined with the profile of the reconstructed beam-beam collisions and with the LHC beam currents to perform precise measurements of the luminosity. This beam-gas imaging (BGI) method also allows one to study the transverse beam shapes, beam positions and angles in real time. Therefore, a demonstrator beam-gas vertex detector (BGV) based on scintillating fibre modules has been built and installed in LHC Ring 2 at point 4.
Imaging the LHC beams with silicon and scintillating fibre vertex detectors
Rihl, M
2016-01-01
The LHCb Vertex Locator (VELO) is used to reconstruct beam–gas interaction vertices which allows one to obtain precise profiles of the LHC beams. In LHCb, this information is combined with the profile of the reconstructed beam–beam collisions and with the LHC beam currents to perform precise measurements of the luminosity. This beam–gas imaging (BGI) method also allows one to study the transverse beam shapes, beam positions and angles in real time. Therefore, a demonstrator beam–gas vertex detector (BGV) based on scintillating fibre modules has been built and installed in LHC Ring 2 at point 4.
Vertex and Propagator in $\\Phi^{4}$ Theory from 4PI Effective Action in Two Dimensions
Carrington, M E
2012-01-01
A set of self-consistent nonlinear integral equations for the four-point vertex and the propagator are derived from the 4-loop 4PI effective action for scalar field theories. This set of integral equations are solved in two dimensions through numerical lattice calculations. We compare the calculated results with those of perturbation theories. We find that the 4PI calculations are well consistent with the perturbation ones in perturbative regions. Non-perturbative results are also obtained in the 4PI formalism when the interacting strength becomes large. Furthermore, the full-momentum dependence of the four-point vertex is easily obtained in the 4PI effective action theories.
Nonperturbative calculation of Green and vertex functions in terms of particle contours
Stefanis, N G
1996-01-01
The infrared regime of fermionic Green and vertex functions is studied analytically within a geometric approach which simulates soft interactions by an {\\it effective} theory of contours. Expanding the particle path integral in terms of dominant contours at large distances, all-order results in the coupling constant are obtained for the renormalized fermion propagator and a universal vertex function with physical characteristics close to those associated with the Isgur-Wise function in the weak decays of heavy mesons. The extension to the ultraviolet regime is scetched.
The Color Antisymmetric Ghost Propagator and One-Loop Vertex Renormalization
Furui, Sadataka
2007-01-01
The color matrix elements of the ghost triangle diagram that appears in the triple gluon vertex and the ghost-ghost-gluon triangle diagram that appears in the ghost-gluon-ghost vertex are calculated. The ghost-ghost-gluon triangle contains a loop consisting of two color diagonal ghosts and one gluon and a loop consisting of two color antisymmetric ghosts and one gluon. Consequently, the pQCD argument in the infrared region based on the one particle irreducible diagram should be modified. Impl...
Consequences Of Fully Dressing Quark-Gluon Vertex Function With Two-Point Gluon Lines
Matevosyan, Hrayr H; Tandy, Peter C
2007-01-01
We extend recent studies of the effects of quark-gluon vertex dressing upon the solutions of the Dyson-Schwinger equation for the quark propagator. A momentum delta function is used to represent the dominant infrared strength of the effective gluon propagator so that the resulting integral equations become algebraic. The quark-gluon vertex is constructed from the complete set of diagrams involving only 2-point gluon lines. The additional diagrams, including those with crossed gluon lines, are shown to make an important contribution to the DSE solutions for the quark propagator, because of their large color factors and the rapid growth in their number.
The SuperB Silicon Vertex Tracker and 3D vertical integration
Re, Valerio
2011-01-01
The construction of the SuperB high luminosity collider was approved and funded by the Italian government in 2011. The performance specifications set by the target luminosity of this machine (> 10^36 cm^-2 s^-1) ask for the development of a Silicon Vertex Tracker with high resolution, high tolerance to radiation and excellent capability of handling high data rates. This paper reviews the R&D activity that is being carried out for the SuperB SVT. Special emphasis is given to the option of exploiting 3D vertical integration to build advanced pixel sensors and readout electronics that are able to comply with SuperB vertexing requirements.
Imaging the LHC beams with silicon and scintillating fibre vertex detectors
Rihl, M
2016-01-01
The LHCb Vertex Locator (VELO) is used to reconstruct beam–gas interaction vertices which allows one to obtain precise profiles of the LHC beams. In LHCb, this information is combined with the profile of the reconstructed beam–beam collisions and with the LHC beam currents to perform precise measurements of the luminosity. This beam–gas imaging (BGI) method also allows one to study the transverse beam shapes, beam positions and angles in real time. Therefore, a demonstrator beam–gas vertex detector (BGV) based on scintillating fibre modules has been built and installed in LHC Ring 2 at point 4.
Ishimoto, Yukitaka
2014-01-01
In order to describe two-dimensionally packed cells in epithelial tissues both mathematically and physically, there have been developed several sorts of geometrical models, such as the vertex model, the finite element model, the cell-centered model, the cellular Potts model. So far, in any case, pressures have not neatly been dealt with and curvatures of the cell boundaries have been even omitted through their approximations. We focus on these quantities and formulate them on the vertex model. Thus, a model with the curvatures is constructed and its algorithm is given for simulation. Its possible extensions and applications will also be discussed.
Marchesini, Ivan; Nowatschin, Dominik; Ott, Jochen; Schmidt, Alexander; Tholen, Heiner [University of Hamburg (Germany)
2015-07-01
In LHC Run II, CMS b-tagging algorithms will employ a new core algorithm, named Inclusive Vertex Finder (IVF). The IVF is designed to perform decay vertex reconstruction of long-lived particles, such as B hadrons. Using only tracks from the silicon tracker, it does not depend on jet clustering and allows for higher reconstruction efficiency of decay vertices, which particularly applies to topologies with two or more decay vertices at low distance. Thus, the IVF will offer increased sensitivity for SM measurements (e.g. angular correlations), but also for the search of BSM physics (e.g. final states with boosted Higgs bosons decaying into b-quarks). For the first time, the dependence of the IVF reconstruction efficiency on the distance of vertices in the η-φ plane is investigated with a data-driven approach. We use a clean set of top quark pair events, selected from data recorded in 2012 in pp-collisions at 8 TeV with the CMS detector, and perform a template fit to a 2D-distribution of the masses of the vertices in an event. Correction factors are derived for the application to simulated events. We conclude that our technique will enable precise calibration of double vertexing with the IVF in the LHC Run II.
Hatami, H.; Magen, A.; Markakis, V.; Charikar, M.; Jansen, K.; Reingold, O.; Rolim, J.
2006-01-01
We study various SDP formulations for {\\sc Vertex Cover} by adding different constraints to the standard formulation. We show that {\\sc Vertex Cover} cannot be approximated better than $2-o(1)$ even when we add the so called pentagonal inequality constraints to the standard SDP formulation, en route
Anisovich, A V; Sarantsev, A V
2016-01-01
Vertex operators for photo- and electro-production of baryon states with arbitrary spin-parity, $ \\gamma + N\\to B(J^P)$, are constructed. The operators obey gauge invariance and analyticity constraints. Analyticity is realized as a requirement of the generalized Siegert theorem for vertex form factors.
Hague, J P
2003-01-01
I apply the newly developed dynamical cluster approximation (DCA) to the calculation of the electron and phonon dispersions in the two-dimensional Holstein model. In contrast to previous work, the DCA enables the effects of spatial fluctuations (non-local corrections) to be examined. Approximations neglecting and incorporating lowest-order vertex corrections are investigated. I calculate the phonon density of states, the renormalized phonon dispersion, the electron dispersion and electron spectral functions. I demonstrate how vertex corrections stabilize the solution, stopping a catastrophic softening of the (pi, pi) phonon mode. A kink in the electron dispersion is found in the normal state along the (zeta, zeta) symmetry direction in both the vertex- and non-vertex-corrected theories for low phonon frequencies, corresponding directly to the renormalized phonon frequency at the (pi, 0) point. This kink is accompanied by a sudden drop in the quasi-particle lifetime. Vertex and non-local corrections enhance th...
On the exact open-closed vertex in plane-wave light-cone string field theory
Lucietti, J; Sinha, A K; Lucietti, James; Schafer-Nameki, Sakura; Sinha, Aninda
2003-01-01
The open-closed vertex in the maximally supersymmetric type IIB plane-wave light-cone string field theory is considered and an explicit solution for the bosonic part of the vertex is derived, valid for all values of the mass parameter, \\mu. This vertex is of relevance to IIB plane-wave orientifolds, as well as IIB plane-wave strings in the presence of D-branes, and their gauge theory duals. Methods of complex analysis are used to develop a systematic procedure for obtaining the solution. This procedure is first applied to the vertex in flat space, and then extended to the plane-wave case. The plane-wave solution for the vertex requires introducing certain ``\\mu-deformed Gamma functions'', which are generalizations of the ordinary Gamma function. The behaviour of the Neumann matrices is graphically illustrated and their large-\\mu asymptotics are analysed.
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.
Bounds on the number of vertex independent sets in a graph
Vestergaard, Preben D.; Pedersen, Anders Sune
2006-01-01
We consider the number of vertex independent sets i(G)In general, the problem of determining the value of i(G) is NP-complete. We present several upper and lower bounds for i(G) in terms of order, size or independence number. We obtain improved bounds for i(G) on restricted graph classes...
RECURSIVE FORMULA FOR CALCULATING THE CHROMATIC POLYNOMIAL OF A GRAPH BY VERTEX DELETION
许进
2004-01-01
A new recursive vertex-deleting formula for the computation of the chromatic polynomial of a graph is obtained in this paper. This algorithm is not only a good tool for further studying chromatic polynomials but also the fastest among all the algorithms for the computation of chromatic polynomials.
Operation of the CDF silicon vertex detector with colliding beams at Fermilab
Bedeschi, F.; Bolognesi, V.; Dell' Agnello, S.; Galeotti, S.; Grieco, G.; Mariotti, M.; Menzione, A.; Punzi, G.; Raffaelli, F.; Ristori, L.; Tartarelli, F.; Turini, N.; Wenzel, H.; Zetti, F. (INFN, University and Scuola Normale Superiore of Pisa, Pisa, Italy, I-56100 (Italy)); Bailey, M.W.; Garfinkel, A.F.; Kruse, M.C.; Shaw, N.M. (Purdue University, West Lafayette, Indiana 47907 (United States)); Carithers, W.C.; Ely, R.; Haber, C.; Holland, S.; Kleinfelder, S.; Merrick, T.; Schneider, O.; Wester, W.; Wong, M.; Yao, W. (Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)); Carter, H.; Flaugher, B.; Nelson, C.; Segler, S.; Shaw, T.; Tkaczyk, S.; Turner, K.; Wesson, T.R. (Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States)); Barnett, B.; Boswell, C.; Skarha, J.; Snider, F.D.; Spies, A.; Tseng, J.; Vejcik, S. (The John Hopkins University, Baltimore, Maryland 21218 (United States)); Amidei, D.; Derwent, P.F.; Song, T.Y.; Dunn, A. (Univer
1992-02-05
In this paper we briefly describe the main features of the CDF Silicon Vertex Detector (SVX) and discuss its performance during actual colliding beam operation at the Fermilab Tevatron. Details on [ital S]/[ital N] ratio, alignment, resolution, and efficiency are given.
Selective attention and the auditory vertex potential. 1: Effects of stimulus delivery rate
Schwent, V. L.; Hillyard, S. A.; Galambos, R.
1975-01-01
Enhancement of the auditory vertex potentials with selective attention to dichotically presented tone pips was found to be critically sensitive to the range of inter-stimulus intervals in use. Only at the shortest intervals was a clear-cut enhancement of the latency component to stimuli observed for the attended ear.
Boundary Correlation Functions of the gl(1|1) Supersymmetric Vertex Model
ZHANG Chen-Jun; ZHOU Jian-Hua; YUE Rui-Hong
2008-01-01
The gl(1|1) supersymmetric vertex model with domain wall boundary conditions (DWBC) on an N×N square lattice is considered.We derive the reduction formulae for the one-point boundary correlation functions of the model.The determinant representation for the boundary correlation functions is also obtained.
Operation of the CDF Silicon Vertex Detector with colliding beams at Fermilab
Bedeschi, F.; Bolognesi, V.; Dell' Agnello, S.; Galeotti, S.; Grieco, G.; Mariotti, M.; Menzione, A.; Punzi, G.; Raffaelli, F.; Ristori, L.; Tartarelli, F.; Turini, N.; Wenzel, H.; Zetti, F. (Scuola Normale Superiore, Pisa (Italy)); Bailey, M.W.; Garfinkel, A.F.; Kruse, M.C.; Shaw, N.M. (Purdue Univ., Lafayette, IN (United States)); Carithers, W.C.; Ely, R.; Haber, C.; Holland, S.; Kleinfelder, S.; Merrick, T.; Schneide
1992-10-01
In this paper we briefly describe the main features of the CDF Silicon Vertex Detector (SVX) and discuss its performance during actual colliding beam operation at the Fermilab Tevatron. Details on S/N ratio, alignment, resolution and efficiency are given.
R and D paths of pixel detectors for vertex tracking and radiation imaging
Battaglia, Marco, E-mail: MBattaglia@lbl.gov [Santa Cruz Institute of Particle Physics, University of California at Santa Cruz, CA 95064 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); CERN, CH-1211 Geneva (Switzerland); Da Viá, Cinzia [University of Manchester, Department of Physics, M13 9PL (United Kingdom); CERN, CH-1211 Geneva (Switzerland); Bortoletto, Daniela [Purdue University, Department of Physics, West Lafayette, IN 47907 (United States); Brenner, Richard [Uppsala Universitet, Department of Physics and Astronomy, S-752 37, Uppsala (Sweden); Campbell, Michael; Collins, Paula [CERN, CH-1211 Geneva (Switzerland); Dalla Betta, Gianfranco [Universitá degli Studi di Trento, Dip. di Ingegneria, I-38123 Povo (Italy); Demarteau, Marcel [Argonne National Laboratory, Argonne, IL 60439 (United States); Denes, Peter [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Graafsma, Heinz; Gregor, Ingrid M. [DESY, D-22607 Hamburg (Germany); Kluge, Alex [CERN, CH-1211 Geneva (Switzerland); Manzari, Vito [INFN, Sezione di Bari, I-70125 Bari (Italy); Parkes, Chris [University of Manchester, Department of Physics, M13 9PL (United Kingdom); Re, Valerio [Universitá degli Studi di Bergamo, Dip. di Ingegneria, I-24044 Dalmine (Italy); Riedler, Petra [CERN, CH-1211 Geneva (Switzerland); Rizzo, Giuliana [Universitá degli Studi di Pisa, Dip. di Fisica and INFN, Sezione di Pisa I-56100 Pisa (Italy); Snoeys, Walter [CERN, CH-1211 Geneva (Switzerland); Wermes, Norbert [Universität Bonn, Physikalisches Institut, D-53115 Bonn (Germany); Winter, Marc [Institut Pluridisciplinaire Hubert Curien, F-67037 Strasbourg (France)
2013-07-11
This report reviews current trends in the R and D of semiconductor pixellated sensors for vertex tracking and radiation imaging. It identifies requirements of future HEP experiments at colliders, needed technological breakthroughs and highlights the relation to radiation detection and imaging applications in other fields of science.
Dynamic bottleneck optimization for k-edge and 2-vertex connectivity
Telelis, Orestis; Zissimopoulos, Vassilis
2008-01-01
We consider the problem of updating efficiently the minimum value b over a weighted graph, so that edges with a cost less than b induce a spanning subgraph satisfying a k-edge or 2-vertex connectivity constraint, when the cost of an edge of the graph is updated. Our results include update...
The silicon drift vertex detector for the STAR experiment at RHIC
Pandey, S U; Beuttenmüller, Rolf H; Caines, H; Chen, W; Dimassimo, D; Dyke, H; Elliot, D; Eremin, V; Grau, M; Hoffmann, G W; Humanic, T; Ilyashenko, Yu S; Kotov, I; Kraner, H W; Kuczewski, P; Leonhardt, B; Li, Z; Liaw, C J; Lo Curto, G; Middelkamp, P; Minor, R; Munhoz, M; Ott, G; Pruneau, C A; Rykov, V L; Schambach, J; Sedlmeir, J; Soja, B; Sugarbaker, E R; Takahashi, J; Wilson, K; Wilson, R
2002-01-01
The current status of the STAR Silicon Vertex Tracker (SVT) is presented. The performance of the Silicon Drift Detectors (SDD) is discussed. Results for a recent 15 layer SDD tracker which prototypes all components of the SVT are presented. The enhanced physics capabilities of the STAR detector due to the addition of the SVT are addressed.
Algebraic Bethe Ansatz Solution to CN Vertex Model with Open Boundary Conditions
LI Guang-Liang; SHI Kang-Jie; YUE Rui-Hong
2005-01-01
We present three diagonal reflecting matrices for the CN vertex model with open boundary conditions and exactly solve the model by using the algebraic Bethe ansatz. The eigenvector is constructed and the eigenvalue and the associated Bethe equations are achieved. All the unwanted terms are cancelled out by three kinds of identities.
A spin glass approach to the directed feedback vertex set problem
Zhou, Hai-Jun
2016-01-01
A directed graph (digraph) is formed by vertices and arcs (directed edges) from one vertex to another. A feedback vertex set (FVS) is a set of vertices that contains at least one vertex of every directed cycle in this digraph. The directed feedback vertex set problem aims at constructing a FVS of minimum cardinality. This is a fundamental cycle-constrained hard combinatorial optimization problem with wide practical applications. In this paper we construct a spin glass model for the directed FVS problem by converting the global cycle constraints into local arc constraints, and study this model through the replica-symmetric (RS) mean field theory of statistical physics. We then implement a belief propagation-guided decimation (BPD) algorithm for single digraph instances. The BPD algorithm slightly outperforms the simulated annealing algorithm on large random graph instances. The predictions of the RS mean field theory are noticeably lower than the BPD results, possibly due to its neglect of cycle-caused long ra...
The staggered six-vertex model: Conformal invariance and corrections to scaling
Frahm, Holger [Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstraße 2, 30167 Hannover (Germany); Seel, Alexander [Lehrstuhl für Theoretische Elektrotechnik und Photonik, Universität Siegen, Hölderlinstraße 3, 57068 Siegen (Germany)
2014-02-15
We study the emergence of non-compact degrees of freedom in the low energy effective theory for a class of Z{sub 2}-staggered six-vertex models. In the finite size spectrum of the vertex model this shows up through the appearance of a continuum of critical exponents. To analyze this part of the spectrum we derive a set of coupled nonlinear integral equations from the Bethe ansatz solution of the vertex model which allow to compute the energies of the system for a range of anisotropies and of the staggering parameter. The critical theory is found to be independent of the staggering. Its spectrum and density of states coincide with the SL(2,R)/U(1) Euclidean black hole conformal field theory which has been identified previously in the continuum limit of the vertex model for a particular ‘self-dual’ choice of the staggering. We also study the asymptotic behavior of subleading corrections to the finite size scaling and discuss our findings in the context of the conformal field theory.
The staggered six-vertex model: Conformal invariance and corrections to scaling
Frahm, Holger; Seel, Alexander
2014-02-01
We study the emergence of non-compact degrees of freedom in the low energy effective theory for a class of Z2-staggered six-vertex models. In the finite size spectrum of the vertex model this shows up through the appearance of a continuum of critical exponents. To analyze this part of the spectrum we derive a set of coupled nonlinear integral equations from the Bethe ansatz solution of the vertex model which allow to compute the energies of the system for a range of anisotropies and of the staggering parameter. The critical theory is found to be independent of the staggering. Its spectrum and density of states coincide with the SL(2,R)/U(1) Euclidean black hole conformal field theory which has been identified previously in the continuum limit of the vertex model for a particular ‘self-dual' choice of the staggering. We also study the asymptotic behavior of subleading corrections to the finite size scaling and discuss our findings in the context of the conformal field theory.
Vertex operator approach to semi-infinite spin chain : recent progress
Kojima, Takeo
2014-01-01
Vertex operator approach is a powerful method to study exactly solvable models. We review recent progress of vertex operator approach to semi-infinite spin chain. (1) The first progress is a generalization of boundary condition. We study $U_q(\\widehat{sl}(2))$ spin chain with a triangular boundary, which gives a generalization of diagonal boundary [Baseilhac and Belliard 2013, Baseilhac and Kojima 2014]. We give a bosonization of the boundary vacuum state. As an application, we derive a summation formulae of boundary magnetization. (2) The second progress is a generalization of hidden symmetry. We study supersymmetry $U_q(\\widehat{sl}(M|N))$ spin chain with a diagonal boundary [Kojima 2013]. By now we have studied spin chain with a boundary, associated with symmetry $U_q(\\widehat{sl}(N))$, $U_q(A_2^{(2)})$ and $U_{q,p}(\\widehat{sl}(N))$ [Furutsu-Kojima 2000, Yang-Zhang 2001, Kojima 2011, Miwa-Weston 1997, Kojima 2011], where bosonizations of vertex operators are realized by "monomial" . However the vertex ope...
Perturbative Correction to Transverse Ward-Takahashi Relation for the Vector Vertex
HE Han-Xin; YU Hong-Wei
2003-01-01
We re-derive exactly the transverse Ward-Takahashi relation for the vector vertex in momentum space.The result shows that this transverse Ward-Takahashi relation in momentum space involves a perturbative correction term. We demonstrate explicitly that this transverse Ward-Takahashi relation is satisfied indeed at one-loop order.
Center of the quantum affine vertex algebra associated with trigonometric R-matrix
Kožić, Slaven; Molev, Alexander
2017-08-01
We consider the quantum vertex algebra associated with the trigonometric R-matrix in type A as defined by Etingof and Kazhdan. We show that its center is a commutative associative algebra and construct an algebraically independent family of topological generators of the center at the critical level.
A novel method to bracket the corotation radius in galaxy discs: vertex deviation maps
Roca-Fàbrega, Santi; Antoja, Teresa; Figueras, Francesca; Valenzuela, Octavio; Romero-Gómez, Mercè; Pichardo, Bárbara
2014-01-01
We map the kinematics of stars in simulated galaxy discs with spiral arms using the velocity ellipsoid vertex deviation (l_v). We use test particle simulations, and for the first time, fully self-consistent high-resolution N-body models. We compare our maps with the tight winding approximation model
A novel method to bracket the corotation radius in galaxy discs: vertex deviation maps
Roca-Fàbrega, Santi; Antoja, Teresa; Figueras, Francesca; Valenzuela, Octavio; Romero-Gómez, Mercè; Pichardo, Bárbara
2014-05-01
We map the kinematics of stars in simulated galaxy discs with spiral arms using the velocity ellipsoid vertex deviation (l_v). We use test particle simulations, and for the first time, fully self-consistent high-resolution N-body models. We compare our maps with the tight winding approximation model analytical predictions. We see that for all barred models, spiral arms rotate closely to a rigid body manner and the vertex deviation values correlate with the density peak's position bounded by overdense and underdense regions. In such cases, vertex deviation sign changes from negative to positive when crossing the spiral arms in the direction of disc rotation, in regions where the spiral arms are in between corotation radius (CR) and the Outer Lindblad Resonance (OLR). By contrast, when the arm sections are inside the CR and outside the OLR, l_v changes from negative to positive. We propose that measurements of the vertex deviation's pattern can be used to trace the position of the main resonances of the spiral arms. We propose that this technique might exploit future data from Gaia and APO Galactic Evolution Experiment (APOGEE) surveys. For unbarred N-body simulations with spiral arms corotating with disc material at all radii, our analysis suggests that no clear correlation exists between l_v and density structures.
Listrovoy Sergey Vladimirovich
2015-10-01
Full Text Available In this paper the probabilistic method is presented for solving the minimum vertex cover problem using systems of non-linear equations that are formed on the basis of a neighborhood relationship of a particular vertex of a given graph. The minimum vertex cover problem is one of the classic mathematical optimization problems that have been shown to be NP-hard. It has a lot of real-world applications in different fields of science and technology. This study finds solutions to this problem by means of the two basic procedures. In the first procedure three probabilistic pairs of variables according to the maximum vertex degree are formed and processed accordingly. The second procedure checks a given graph for the presence of the leaf vertices. Special software package to check the validity of these procedures was written. The experiment results show that our method has significantly better time complexity and much smaller frequency of the approximation errors in comparison with one of the most currently efficient algorithms.
A characterization of edge reflection positive partition functions of vertex coloring models
G. Regts (Guus)
2013-01-01
htmlabstractSzegedy (B. Szegedy, Edge coloring models and reflection positivity, Journal of the American Mathematical Society 20, 2007, 969-988.) showed that the partition function of any vertex coloring model is equal to the partition function of a complex edge coloring model. Using some results in
A characterization of edge-reflection positive partition functions of vertex-coloring models
G. Regts (Guus); J. Nešetřil (Jaroslav); M Pellegrini
2013-01-01
htmlabstractSzegedy (B. Szegedy, Edge coloring models and reflection positivity, Journal of the American Mathematical Society 20, 2007, 969-988.) showed that the partition function of any vertex coloring model is equal to the partition function of a complex edge coloring model. Using some results in
A blind watermarking algorithm for 3D mesh models based on vertex curvature
Yong-zhao ZHAN; Yan-ting LI; Xin-yu WANG; Yi QIAN
2014-01-01
We propose a robust blind watermarking algorithm for three-dimensional (3D) mesh models based on vertex cur-vature to maintain good robustness and improve visual masking in 3D mesh models. In the embedding process, by using the local window of vertex, the root mean square curvature is calculated for every vertex of the 3D mesh model and an ordered set of fluctuation values is obtained. According to the ordered fluctuation values, the vertices are separated into bins. In each bin the fluctuation values are normalized. Finally, the mean of the root mean square curvature fluctuation values of the vertices in each bin is modulated to embed watermark information. In watermark detection, the algorithm uses a blind watermark extraction technique to extract the watermark information. The experimental results show that the algorithm has a very good performance for visual masking of the embedded model and that it can resist a variety of common attacks such as vertex rearrangement, rotation, trans-lating, uniform scaling, noise, smoothing, quantization, and simplification.
Convergence of the Stochastic Six-Vertex Model to the ASEP
Aggarwal, Amol, E-mail: amolaggarwal@g.harvard.edu [Harvard University Cambridge (United States)
2017-06-15
In this note we establish the convergence of the stochastic six-vertex model to the one-dimensional asymmetric simple exclusion process, under a certain limit regime recently predicted by Borodin-Corwin-Gorin. This convergence holds for arbitrary initial data.
Kim, Taekwang; Kitazawa, Masakiyo
2016-01-01
We analyze the production rate of photons from the thermal medium above the deconfinement temperature with a quark propagator obtained from a lattice QCD numerical simulation. The photon-quark vertex is determined gauge-invariantly, so as to satisfy the Ward-Takahashi identity. The obtained photon production rate shows a suppression compared to perturbative results.
Control and data acquisition electronics for the CDF Silicon Vertex Detector
Turner, K.J.; Nelson, C.A.; Shaw, T.M.; Wesson, T.R.
1991-11-01
A control and data acquisition system has been designed for the CDF Silicon Vertex Detector (SVX) at Fermilab. The system controls the operation of the SVX Rev D integrated circuit (SVX IC) that is used to instrument a 46,000 microstrip silicon detector. The system consists of a Fastbus Sequencer, a Crate Controller and Digitizer modules. 11 refs., 6 figs., 3 tabs.
R&D Paths of Pixel Detectors for Vertex Tracking and Radiation Imaging
Battaglia, M; Bortoletto, D; Brenner, R; Campbell, M; Collins, P; Dalla Betta, G F; Demarteau, Marcel; Denes, P; Graafsma, H; Gregor, I M; Kluge, A; Manzari, V; Parkes, C; Re, V; Riedler, P; Rizzo, G; Snoeys, W; Wermes, Norbert; Winter, M
2013-01-01
This report reviews current trends in the R&D of semiconductor pixellated sensors for vertex tracking and radiation imaging. It identifies requirements of future HEP experiments at colliders, needed technological breakthroughs and highlights the relation to radiation detection and imaging applications in other fields of science.
The Hidden Quantum Group of the 8-vertex Free Fermion Model q-Clifford Algebras
Cuerno, R; López, E; Sierra, G
1993-01-01
We prove in this paper that the elliptic $R$--matrix of the eight vertex free fermion model is the intertwiner $R$--matrix of a quantum deformed Clifford--Hopf algebra. This algebra is constructed by affinization of a quantum Hopf deformation of the Clifford algebra.
Study of a DEPFET vertex detector and of supersymmetric smuons at the ILC
Chen, Xun
2009-01-21
This thesis is devoted to the study of the performance of a pixel vertex detector based on DEPFET technology at the International Linear Collider (ILC). The ILC is the proposed next generation e{sup +}e{sup -} collider to explore the physics at the Terascale. At the ILC with its well-defined initial state of collisions, possible discoveries at the Large Hadron Collider can be verified and studied more accurately. It is expected that the precision measurements of the ILC will answer many fundamental questions about the universe, such as the generation of particle masses and the origin of electroweak spontaneous symmetry breaking. The ambitious physics goals present challenges to the ILC detectors. Several detector concepts have been proposed in recent years. A crucial device for all these concepts is the pixel vertex detector. It provides precise impact parameter information of charged particles, jet flavor tagging and improves overall tracking efficiency. To meet the requirements of the ILC environment, the vertex detector will be arranged in a concentric multi-layer array around the interaction point to cover as large a solid angle as possible. Endcap disks are considered in some designs. Silicon pixel sensor technologies must be employed to provide excellent point resolution. The DEPFET technology, which integrates the first level of amplification into a depleted silicon bulk, is one of the promising candidates. The DEPFET sensor is very sensitive with a high signal-to-noise ratio. Power consumption is minimized due to the internal storage of signal charges. The good radiation tolerance makes it capable of working close to the interaction point. In this thesis, we discuss the detailed simulation of the DEPFET vertex detector, following the general vertex detector layout proposed by the TESLA collaboration. The simulation is used to evaluate the impact parameter resolution. We also discuss the DEPFET test beam analysis on two-track resolution. The whole analysis
On the Landau gauge matter-gluon vertex in scalar QCD in a functional approach
Hopfer, Markus
2013-01-01
Recently the quark-gluon vertex has been investigated in Landau gauge using a combined Dyson-Schwinger and nPI effective action approach. We present here a numerical analysis of a simpler system where the quarks have been replaced by charged scalar fields. We solve the coupled system of Dyson-Schwinger equations for the scalar propagator, the scalar-gluon vertex and the Yang-Mills propagators in a truncation related to earlier studies. The calculations have been performed for scalars both in the fundamental and the adjoint representation. A clear suppression of the Abelian diagram is found in both cases. Thus, within the used truncation the suppression of the Abelian diagram predominantly happens dynamically and is to a high degree independent of the colour structure. The numerical techniques developed here can directly be applied to the fermionic case.
TCAD simulations of High-Voltage-CMOS Pixel structures for the CLIC vertex detector
Buckland, Matthew Daniel
2016-01-01
The requirements for precision physics and the experimental conditions at CLIC result in stringent constraints for the vertex detector. Capacitively coupled active pixel sensors with 25 μm pitch implemented in a commercial 180 nm High-Voltage CMOS (HV-CMOS) process are currently under study as a candidate technology for the CLIC vertex detector. Laboratory calibration measurements and beam tests with prototypes are complemented by detailed TCAD and electronic circuit simulations, aiming for a comprehensive understanding of the signal formation in the HV-CMOS sensors and subsequent readout stages. In this note 2D and 3D TCAD simulation results of the prototype sensor, the Capacitively Coupled Pixel Detector version three (CCPDv3), will be presented. These include the electric field distribution, leakage current, well capacitance, transient response to minimum ionising particles and charge-collection.
Power pulsing scheme for analog and digital electronics of the vertex detectors at CLIC
Blanchot, Georges
2015-01-01
The precision requirements of the vertex detector at CLIC impose strong limitations on the mass of such a detector (< 0.2% of a radiation length, Xo, per layer). To achieve such a low material budget, ultra-thin hybrid pixel detectors are foreseen, while the mass for cooling and services will be reduced by implementing a power pulsing scheme that takes advantage of the low duty cycle of the accelerator. The principal aim is to achieve significant power reduction without compromising the power integrity supplied to the front-end electronics. This report summarises the study of a power pulsing scheme to power the vertex barrel electronics of the future CLIC experiment. Its main goal is to describe in more detail what has been already presented in TWEPP conferences and other presentations. The report can therefore serve as an operator manual for future use and development of the system
Exact Calculations of Vertex (-s)γb and (-s)Zb in the Unitary Gauge
无
2007-01-01
In this paper, we present the exact calculations for the vertex -sγb and -sZb in the unitary gauge. We find that we sum up the contributions from four related Feynman diagrams; (b) for an on-shell photon, such terms do not contribute et al.; (c) for off-shell photon, these terms will be canceled when the contributions from both vertex -sγb and -sZb are taken into account simultaneously, and therefore the finite and gauge-independent function Z0 (xt) = C0 (xt) + D0 (xt) / 4,which governs the semi-leptonic decay b → sl-l+, is derived in the unitary gauge.
Internal Alignment of the SLD Vertex Detector using a Matrix Singular Value Decomposition Technique
Su, Dong
2002-01-03
The tracking resolution and vertex finding capabilities of the SLD experiment depend upon a precise knowledge of the location and orientation of the 96 elements of the SLD pixel vertex detector (VXD3) in 3D space. At the heart of the deterministic procedure described here to align the 96 CCDs is the matrix inversion technique of singular value decomposition (SVD). This tool is employed to unfold the detector geometry corrections from the track hit residual data in the VXD3. The algorithm is adapted to perform an optimal {chi}{sup 2} minimization by careful treatment of the errors and correlations in the residual measurements. The general form of the problems that might be solved with this technique is discussed. The tracking resolution obtained with the aligned geometry is compared with the starting point, based on an optical survey of the CCDs, and is shown to achieve the design performance.
Calculation of Wakefields for the New Design of the LHCb Vertex Locator
Wanzenberg, Rainer; CERN. Geneva. ATS Department
2016-01-01
The upgrade of the LHCb detector in the LHCb experiment was planned in 2011. The main purpose of the upgrade is an improvement of the functional abilities of the LHCb detector, such as the measurement and the collection of various characteristics of the particles produced by colliding protons. The new configuration of the LHCb detector will include an upgraded configuration of the LHCb VErtex LOcator (VELO) and a new design of the beam pipe for this detector. The wakefields for the new geometrical model of the beam pipe in the vertex locator have been calculated with the Wakefield Solver of the program CST STUDIO 2015. Preliminary results of the calculations are presented in this report.
Quantum group approach to a soluble vertex model with generalized ice-rule
Cire, L S; Cire, L Sow
1995-01-01
Using the representation of the quantum group SL_q(2) by the Weyl ope\\-ra\\-tors of the canonical commutation relations in quantum mechanics, we construct and solve a new vertex model on a square lattice. Random variables on horizontal bonds are Ising variables, and those on the vertical bonds take half positive integer values. The vertices is subjected to a genera\\-li\\-zed form of the so-called ``ice-rule'', its property are studied in details and its free energy calculated with the method of quantum inverse scattering. Remarkably in analogy with the usual six-vertex model, there exists a ``Free-Fermion'' limit with a novel rich operator structure. The existing algebraic structure suggests a possible connection with a lattice neutral plasma of charges, via the Fermion-Boson correspondence.