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Sample records for detecteur lhcb au

  1. Design and implementation of the decision unit of the first level trigger system of the LHCb detector at the Large Hadron Collider (LHC); Conception et realisation de l'unite de decision du systeme de declenchement de premier niveau du detecteur LHCb au LHC

    Energy Technology Data Exchange (ETDEWEB)

    Laubser, J

    2007-11-15

    The LHCb experiment is one of the four particle physic detector installed at the new Large Hadron Collider (LHC) at CERN in Geneva. In order to reduce the amount of data storage for offline analysis, an online trigger system of interesting event according to the studied physic is implemented in parallel of the Data Acquisition system. The trigger system is composed by a first level (Level-0) made by a complex electronic system and a second level made by a computing system called the High Level Trigger. The Level-0 Decision Unit is the central part of the first trigger level that takes the decision to accept or to reject the event by using a fraction of information coming from the fastest sub-triggers (432 bits at 80 MHz). It is a full custom 16 layers board using advanced FPGA (Field Programmable Gate Array) in BGA (Bill Grid Array) package. Each sub-trigger transmit their data via high speed optical links running at 1.6 Gbit/s. The processing is implemented using a 40 MHz synchronous pipelined architecture. It performs a simple physical algorithm to compute the Level-0 trigger decision in order to reduce the data flow from 40 MHz down to 1 MHz for the next trigger level. The internal design of the processing FPGA is mainly composed by a Partial Data Processing (PDP) and a Trigger Definition Unit (TDU). The aim of the PDP is to adjust the clock phase, perform the time alignment, prepare the data for the TDU and monitor the data processing. The TDU is flexible and allows to fully re-configure all the trigger conditions through the Experiment Control System without any FPGA re-programming. (author)

  2. Study of thick, nuclear-compensated silicon detectors; Etude des detecteurs epais au silicium compense nucleairement

    Energy Technology Data Exchange (ETDEWEB)

    Le Coroller, Y. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-09-01

    A study is made here, from the point of view of the realization and the performance, of thick nuclear-compensated silicon detectors. After recalling the need for compensation and reviewing the existing methods, the author describes in detail the controlled realization of thick detectors by nuclear compensation from the theoretical and experimental points of view. The practical precautions which should be observed are given: control of the homogeneity of the starting material, control of the evolution of the compensation, elimination of parasitic processes. The performances of the detectors obtained are then studied: electrical characteristics (current, life-time) on the one hand, detection and spectrometry of penetrating radiations on the other hand. The results show, that the compensated diodes having an effective thickness of two millimeters operate satisfactorily as detectors for applied voltages of about 500 volts. The resolutions observed are then about 2 per cent for mono-energetic electrons and about 4 per cent for the gamma; they can be improved by the use of a pre-amplifier of very low background noise. (author) [French] Les detecteurs epais au silicium compense nucleairement sont etudies ici du double point de vue realisation et performances. Apres un rappel sur la necessite de la compensation et les procedes existants, la realisation controlee des detecteurs epais par compensation nucleaire est decrite en detail sous l'aspect theorique et l'aspect experimental. On met en evidence les precautions a prendre dans la pratique: controle de l'homogeneite du materiau de base, controle de l'evolution de la compensation, elimination des processus parasites. On etudie ensuite les performances de detecteurs obtenus : caracteristiques electriques (courant, duree de vie) d'une part, d'autre part detection et spectrometrie des rayonnements penetrants. Les resultats montrent que les diodes compensees ayant une epaisseur utile de deux

  3. Study of thick, nuclear-compensated silicon detectors; Etude des detecteurs epais au silicium compense nucleairement

    Energy Technology Data Exchange (ETDEWEB)

    Le Coroller, Y [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-09-01

    A study is made here, from the point of view of the realization and the performance, of thick nuclear-compensated silicon detectors. After recalling the need for compensation and reviewing the existing methods, the author describes in detail the controlled realization of thick detectors by nuclear compensation from the theoretical and experimental points of view. The practical precautions which should be observed are given: control of the homogeneity of the starting material, control of the evolution of the compensation, elimination of parasitic processes. The performances of the detectors obtained are then studied: electrical characteristics (current, life-time) on the one hand, detection and spectrometry of penetrating radiations on the other hand. The results show, that the compensated diodes having an effective thickness of two millimeters operate satisfactorily as detectors for applied voltages of about 500 volts. The resolutions observed are then about 2 per cent for mono-energetic electrons and about 4 per cent for the gamma; they can be improved by the use of a pre-amplifier of very low background noise. (author) [French] Les detecteurs epais au silicium compense nucleairement sont etudies ici du double point de vue realisation et performances. Apres un rappel sur la necessite de la compensation et les procedes existants, la realisation controlee des detecteurs epais par compensation nucleaire est decrite en detail sous l'aspect theorique et l'aspect experimental. On met en evidence les precautions a prendre dans la pratique: controle de l'homogeneite du materiau de base, controle de l'evolution de la compensation, elimination des processus parasites. On etudie ensuite les performances de detecteurs obtenus : caracteristiques electriques (courant, duree de vie) d'une part, d'autre part detection et spectrometrie des rayonnements penetrants. Les resultats montrent que les diodes compensees ayant une epaisseur utile de deux millimetres fonctionnent

  4. Thermal, intermediate and fast neutron flux measurements using activation detectors; Mesure des flux de neutrons thermiques, intermediaires et rapides au moyen de detecteurs par activation

    Energy Technology Data Exchange (ETDEWEB)

    Brisbois, J; Lott, M; Manent, G [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-07-01

    The problem of neutron flux measurements using activation detectors is studied in the particular case of protection research. It is shown how it possible, it is possible, using a known thermal flux, to organise a coherent calibration system for all the detectors. The rapid neutron detectors are calibrated with respect to a reference detector (phosphorus) in a natural uranium converter; the intermediate neutron detectors with respect to gold in the axial channel of ZOE. This method makes it possible to minimise the errors due to the activation cross-sections. A brief description is given of the counting room of the Pile Safety Study Service, as well of the practical utilisation characteristics of the counters employed. (authors) [French] Le probleme de la mesure des flux de neutrons au moyen de detecteurs par activation est etudie dans le cas particulier des etudes de protections. On montre comment, a partir d'un flux thermique connu, on peut organiser un systeme coherent d'etalonnage de tous les detecteurs. Les detecteurs de neutrons rapides sont etalonnes par rapport a un detecteur de reference (phosphore) dans un convertisseur en uranium naturel; les detecteurs de neutrons intermediaires, par rapport a l'or dans le canal axial de ZOE, Cette methode permet de minimiser les erreurs dues aux sections efficaces d'activation. On decrit sommairement la salle de comptage du Service d'Etudes de Protections de Piles et on indique les caracteristiques d'emploi pratique des detecteurs utilises. (auteurs)

  5. LHCb

    CERN Multimedia

    Frank, M; Neufeld, N; Ruf, T; Batista lopes, J C; Martinelli, M; Perazzini, S; Stagni, F; Dorigo, M; Di canto, A; Nolte, N S; Battista, V; Birnkraut, A; Uwer, U; Zhelezov, A; Han, X; Kolpin, M; Le gac, R; Wormser, G H M; Barsuk, S; Maurice, E A; Renaudin, V; Benayoun, M C; Polci, F; Watson, N; Souza covacich, D; Barlow, R J; Pastore, A; Lax, I; Peco, G; Bortolotti, D; Vilaca pinheiro soares, M; Leflat, A; Krokovnyi, P; Gibson, V; Ward, D R; Doherty, F; Longstaff, I R; Dean, C T; Traill, M T; Fiorini, M; Campana, P; Saputi, A; Ciambrone, P; Michielin, E; Morello, M J; Carboni, G; Van veghel, M; Raven, G H; Witek, M; Ossowska, A; Fiutowski, T A; Dzhelyadin, R; Stenyakin, O; Popov, A; Wang, J; Artuso, M; Rudolph, M S; Batsukh, B; Mendes gandelman, M; Garrido beltran, L; Rosello canal, M D M; Luengo alvarez, S; Picatoste olloqui, E; Sanchez gonzalo, D; Wilson, F F; Nandakumar, R; Wark, H M; Hecker, M; Kochenda, L; Petrolini, A; Saitta, B; Belin, S; Calvi, M; Pessina, G E; Shao, B; Zeng, M; Sun, J; Kechadi, M T; Zheng, Y; Lyu, X; Polukhina, N; Gromov, S; Seco miguelez, M A; Vazquez regueiro, P; Fernandez prieto, A; Buytaert, J; Camilleri, L L; Lindner, R; Corti, G; Ponce, S; Coco, V; Schwemmer, R A; Ravonel salzgeber, M; Gruber, L; Seyfert, P; Stahl, S; De aguiar francisco, O A; Chrzaszcz, M J; Voneki, B; Masson, G A; Rodrigues cavalcante, A B; Marino, P; Vollhardt, A; Zhukov, V; Haas, T; Leroy, O; Mancinelli, G; Hachon, F; Stocchi, A; Lisovskyi, V; Naik, P P; Richards, S E; John, M; Nandi, A K; Palano, A; Iarocci, E; Sciubba, A; Auriemma, G; Shapoval, I; Philippov, S; Petrov, A; Basiladze, S; Kozachuk, A; Berdiouguine, A; Weisser, C N; Graziani, G; Anderlini, L; Evans, H M; Garsed, P J; Eklund, L M; Alexander, M T; Tellarini, G; Capon, G; Bloise, C; Santimaria, M; Lucchesi, D; Bedeschi, F; Van beuzekom, M G; Berkien, A; Giubega, L; Koliiev, S; Volkov, V; Sokoloff, M D; Pappenheimer, C A; Da silva, C L; Blusk, S R; Ely, S E; Wilkinson, M K; Marangotto, D; Santana rangel, M; Camboni, A; Orellana martin, D; Niess, V; Franek, B; Loveridge, P; Hutchcroft, D E; Shears, T G; Smith, A N; Whitley, M D A; Marshall, P J; Sutcliffe, W L; Sagidova, N; Vznuzdaev, M; Aidala, C A; Sun, Y; Fontana, M; Mazza, R; Cheng, J; Huang, Y; Luo, Y; Hushchyn, M; Hess, M; Perez trigo, E; Borsato, M; Crocombe, A C; Needham, M D; Petrucci, S; Jacobsson, R; Khanji, B; Mathe, Z; Rauschmayr, N; Pearce, A; Byczynski, W; Frei, R; Nakada, T; Nguyen mau, C; Pinard, A; Schulte, S; Bernet, R; Serra, N; Bezshyiko, I; Wang, Y; Kirn, T; Guth, A; Kruse, F; Bauer, C; Dembinski, H P; Braun, S A; Piucci, A; Kecke, M; Minard, M; Aslanides, E; Barrand, G C; Lefrancois, J; Chamont, D; Usachov, A; Billoir, P; Del buono, L; Ben haim, E; Bertholet, E; Plews, J P; Velthuis, J J; Dalseno, J P; Borghi, S; Appleby, R B; Hombach, C; Sarpis, G; Capriotti, L; Hilton, M; Pullen, H L; Galli, D; Garibaldi, F; Shatalov, P; Nikitin, N; Williams, J M; Boettcher, T J; Smith, J W; Williams, I; Spradlin, P M; Calabrese, R; Neri, I; Skiba, I; Bencivenni, G; Lanfranchi, G; Simi, G; Ceelie, L; Van petten, O R; Pellegrino, A; Roeland, E; Dendek, A M; Obraztsov, V; Stone, S L; Olejnik, L; Petruzzo, M; Hicheur, A; Silva de oliveira, L G; Lebsir, B; Golutvin, A; Humair, T; Moise, R; Bartolini, M; Gao, Y; Liu, X; Zhu, X; Milanes carreno, D A; Rodriguez lopez, J A; Borisyak, M; Szymanski, M P; Krasilnikova, I; Meinert, N; Adeva andany, B; Hernando morata, J A; Sanmartin sedes, B; Millard, E J; Webster, J; Correa dos reis, A; Gomes dos santos neto, A; Brarda, L; D'ambrosio, C; Ferro-luzzi, M; Gys, T; Schopper, A; Teubert, F; Wyllie, K; Couturier, B; Kristic, R; Fournier, C; Haen, C D; Ciezarek, G M; Durante, P; Lupton, O J; Pais, P R; Kirsebom, V S; Straumann, U D; Mueller, K; Buonaura, A; Spaan, B; Albrecht, J; Ekelhof, R J; Shires, A; Schlupp, M; Demmer, M; Muller, J; Schmelzer, T; Lindemann, T; Bachmann, S; Cachemiche, J; De abreu barbosa coelho, J; Tou, D Y; Calladine, R B; Pomery, G J; Bhasin, S; De capua, S; Burr, C M; Topp-joergensen, S; Bjorn, M; Patrignani, C; Vagnoni, V M; Kandybei, S; Shekhtman, L; Jones, C R; Cliff, H V; Sirendi, M; Tully, A M; Soler jermyn, P F; Luppi, E; Vecchi, S; De simone, P; Rotondo, M; Satta, A; Merk, M; Jans, E; Krzemien, W J; Merkin, M; Vasilyev, A; Durham, J M; Poliakova, M; Merli, A; Souza de paula, B; Pinto eboli, O J; Vilasis cardona, J; Ajaltouni, Z; Quintana, B J; Casse, G; Hennessy, K P; Rinnert, K; Dornan, P J; Patel, M; Savidge, T E; Baker, S K; Spiridenkov, E; Makarenkov, G; Filimonov, A; Stepanova, M; Jawahery, A; Parker, W C; Belloli, N; Gong, G; Zhang, W; Gan, Y; Ruiz vidal, J; Raab, N V; Huang, W; Cai, H; Bian, L; Waldi, R G; Gershon, T J; Playfer, S M; Gizdov, K; Marques de miranda, J; De bediaga hickman, I A; Marujo da silva, F; Silveira mizher, A J; Dijkstra, H; Van herwijnen, E; Forty, R; Gaspar, C; Hatch, M; Jost, B; Piedigrossi, D; Alessio, F; Vazquez gomez, R; Johnson, D; Pisani, F; Tran, M; Repond, J; Macko, V; Yu, J; Heister, A; Tekampe, T; Hofmann, W; Schmelling, M T; Rummel, C; Machefert, F; Fleuret, F D; Bossu, F; Lazzeroni, C; Zarebski, K A; Saunders, D M; Mcnab, I A; Maguire, K S; Dutta, D; Pinci, D; Shevchenko, O; Gushchin, E; Nogay, A; Belyaev, I; Semennikov, A; Danilina, A; Gorelov, I V; Haines, S C; Delaney, B; Bozzi, C; Sciascia, B; Fantechi, R; Groep, D L; Onderwater, C; Glab, S M; Idzik, M A; Firlej, M; Guzik, Z; Maciuc, F; Pirghie, A; Pugatch, V; Okhrimenko, O; Belous, K; Ostankov, A; Meadows, B; Niu, N; Salazar de paula, L; Polycarpo macedo, E; Lefevre, R P; Websdale, D M; Maev, E; Mattioli, K R; Hamilton, B K; Lai, A; Liu, B; Jiang, F; Cang, J; Vagner, A; Saborido silva, J J; Muheim, F; Collins, P; Schneider, T H; Granado cardoso, L A; Valat, S J; Dordei, F; Karacson, M; Schneider, O P; Haefeli, G J; Hopchev, P H; Maurin, B E; Redi, F L; Stefko, P; Wang, Z; Schael, S; Knopf, J M; D'argent, P; Pietrzyk, B; Drancourt, C; T'jampens, S; Duval, P; Cogan, J; Beigbeder-beau, C; Slater, M W; Farley, N; Williams, T; Adinolfi, M; Prouve, C; Parkes, C J; Gronbech, P D; Hancock, T H; Rollings, A P; Zucchelli, S; Bocci, V; Satriano, C; Golubkov, D; Kvaratskheliya, T; Egorychev, V; Bondar, A; Eydelman, S; Kuzmin, A; Krokovny, P; Veltri, M; Bettler, M O; Schiller, M T; Felici, G; Morandin, M; Doets, M; Schimmel, A; Kraan, M J; Vink, W; Vitkovskiy, A; Szumlak, T; Straticiuc, M; Guz, Y; Artamonov, A; Rodrigues figueiredo, E M; Xing, Z; Beiter, A; Lopes, H J; Gascon, D; Casajus ramo, A; Trenado garcia, J; Golobardes ribe, E; Alfonso albero, A; Deschamps, O; Cooke, P A; Wormald, M; Stefkova, S; Tilley, M J; Newcombe, R; Levitskaya, O; Golovtcov, V; Semenchuk, G; Roth, J D; Dean, W; Matteuzzi, C; Martinez vidal, F; Henry, L; Garcia martin, L M; Qin, J; Xu, Q; Didenko, S; Gallas torreira, A A; Chobanova, V G; Ramos pernas, M; Poluektov, A; Latham, T E; Blake, T; Eisenhardt, S; Cattaneo, M; Chadaj, B; Charpentier, P; Closier, J; Jamet, O; Lacarrere, D; Schmidt, B; Clemencic, M; Thomas, E P C; Schindler, H; Faerber, C; Matev, R I; Colombo, T; Muller, D; Bay, A; Gonzalez, R; Girard, O G; Atzeni, M; Xiao, D; Mueller, V; Hansmann-menzemer, S; Nikodem, T; Leverington, B D; Ghez, P; Xu, Z; Tsaregorodtsev, A; Serrano, J; Schune, M; Jouvin, M; Robbe, P A; Duarte, O; Balagura, V; Vom bruch, D; Rademacker, J H; Kariuki, J M; Lafferty, G D; Gersabeck, M; Harnew, N; Malde, S S; Gruberg cazon, B R; Marconi, U; Valenti, G; Carbone, A; Betti, F; Santacesaria, R; Kravchuk, L; Maltsev, T; Gobel burlamaqui de mello, C; Wotton, S; Garra tico, J; Baldini, W; Tomassetti, L; Andreotti, M; Siddi, B G; Palutan, M; Tagnani, D; Busetto, G; Walsh, J J; Punzi, G; Santovetti, E; Berbee, E M; Lesiak, T; Wiechczynski, J P; Baszczyk, M K; Muryn, B; Ukleja, A; Batozskaya, V; Cojocariu, L N; Shapkin, M; Romanovskiy, V; Luchinskii, A; Huard, Z C; Otalora goicochea, J M; Graciani diaz, R; Grauges pous, E; Coquereau, S; Monteil, S; Chanal, H P; Cogneras, E R D; Vert, P; Puech, G; Easo, S; Bowcock, T; Egede, U; Neustroev, P; Kashchuk, A; Petrov, G; Fontanelli, F; Cadeddu, S; Cogoni, V; De oyanguren campos, M A; Mcnulty, R C; Ratnikov, F; He, J; Li, P; Baryshnikov, F; Shmanin, E; Viemann, H M; Santamarina rios, C; Mathad, A; Loh, D J; Costa sobral, C M; Cowan, G A; Smith, I T; Kos antunes maciel, A; Santana, R; Pepe-altarelli, M; Dumps, R; Frei, C M; Roy, L; De bruyn, K A M; Tolk, S; Brodski, M; Sciuccati, A; Fernandez declara, P; Blanc, F H; Graverini, E; Mukherjee, M; Yin, H; Voss, H H; Moch, M; Decamp, D L; Arnau romeu, J; Breton, D R; Charlet, D M; Amhis, Y S; Buchanan, E; Hidalgo charman, R; Harris, F J; Hill, D; Hadavizadeh, T B; De serio, M; Martellotti, G; Dovbnya, A; Kutuzov, V; Zhivaeva, L; Bogdanova, G; Vorobyev, V; Kaminer, I E; Bizzeti, A; Passaleva, G; Lovell, G H; Smeaton, J G; Pappalardo, L L; Anelli, M; Amerio, S; Lupato, A; Sluijk, T; Munneke, B; Mulder, M; Dufour, L; Dorosz, P A; Melnychuk, D; Grecu, A T; Pirghie, C; Yushchenko, O; Likhoded, A; Soldatov, M; Schreiner, H F; Mountain, R J; Skwarnicki, T; Kelsey, M J; Venkateswaran, A; Yao, Y; Neri, N; Amato, S F; Calvo gomez, M G; Gonzalez bano, C; Henrard, P; Perret, P; Magne, M M; Maratas, J; Gazzoni, G; Ricciardi, S; Gamet, R; Noor, A; Liles, M M; Pritchard, A A; Cunliffe, S T; Alkhazov, G; Trofimov, V; Shapkin, G; Smirenin, Y; Yang, Z; Cardini, A; Brundu, D; Gong, H; Yang, Z; Mazorra de cos, J; Sanchez mayordomo, C; Evangelho vieira, D; Pazos alvarez, A; Kreps, M; Clarke, P; Gabriel, E P M

    2002-01-01

    The LHCb detector is designed to study CP violation and other rare phenomena in decays of hadrons with heavy flavours, in particular $ \\rm B_s$ mesons. Interest in CP violation comes not only from elementary particle physics but also from cosmology, in order to explain the dominance of matter over antimatter observed in our universe, which could be regarded as the largest CP violation effect ever seen. The LHCb experiment will improve significantly results from earlier experiments both quantitatively and qualitatively, by exploiting the large number of different kinds of b hadrons produced at LHC. This is done by constructing a detector which has \\begin{enumerate} \\item Good trigger efficiencies for b-hadron final states with only hadrons, as well as those containing leptons. \\item Capability of identifying kaons and pions in a momentum range of $\\sim 1$ to above 100 GeV/$c$. \\item Excellent decay time and mass resolution. \\end{enumerate} The LHCb spectrometer shown in the figure consists of the following det...

  6. Conception et réalisation de l'unité de décision du système de déclenchement de premier niveau du détecteur LHCb au LHC

    CERN Document Server

    Laubser, Julien

    2007-01-01

    Le detecteur LHCb est l'une des quatre experiences de physique des particules installees sur la nouvelle chaine d'acceleration LHC (Large Hadron Collider) du CERN a Geneve. Afin de reduire la quantite de donnees destinees au stockage pour les analyses hors ligne, un dispositif de selection en ligne des collisions interessantes selon la physique a etudier est mis en place en parallele de la chaine d'acquisition des donnees. Ce dispositif est compose d'un premier niveau(niveau 0) realise par un systeme electronique complexe et d'un second niveau de selection realise par informatique HLT (High Level Trigger). L'unite de decision de niveau 0 (L0DU) est le systeme central du niveau 0 de declenchement. L0DU prend la decision d'accepter ou de rejeter la collision pour ce premier niveau a partir d'une fraction d'informations issues des sous-detecteurs les plus rapides (432 bits a 80 MHz). L'unite de decision est un circuit imprime 16 couches integrant des composants de haute technologie de type FPGA (Field Programmab...

  7. Study of Au+Au relativistic collisions with the Fopi-Phase I detector; Etude des collisions relativistes Au+Au avec le detecteur Fopi-Phase I

    Energy Technology Data Exchange (ETDEWEB)

    Dupieux, P

    1995-01-01

    Au+Au relativistic collisions, in a 100-1000 MeV energy domain per nucleon, are described. Experiments have been carried out with the SIS accelerator at GSI/Darmstadt. Data are analysed with the FOPI-phase I detector. These data are compared with IQMD model (Isospin Quantum Molecular Dynamics) Predictions. (S.G). 80 refs., 77 figs., 5 tabs.

  8. Germanium junction detectors. Theoretical and practical factors governing their use in radiation spectrometry; Detecteurs a jonction au germanium. Elements theoriques et pratiques pour l'utilisation en spectrometrie de rayonnements

    Energy Technology Data Exchange (ETDEWEB)

    Hors, M; Philis, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-07-01

    Semi-conductor detectors have recently greatly increased the possibilities available to nuclear spectroscopists for the study of {alpha}, {beta} and {gamma} radiations. Their use in radio-chemistry has encouraged us to study their principle, their mechanism and also the conditions under which they can be used. The first part, which is theoretical, consists of a summary of what should be known concerning the best use of junction detectors, in particular Ge (Li) detectors. The second part, which is experimental, summarizes the laboratory work carried out over a period of one year on Ge (Li) detectors. Stress is laid on the possibilities presented by the use of these detectors as photo-electric spectrometers, and also on the precautions required. Amongst the numerous results presented, the resolution of 2.52 keV obtained for the {gamma} radiation of 145.5 keV for {sup 141}Ce may be particularly noted. (authors) [French] Les detecteurs a semi-conducteurs ont recemment accru les possibilites offertes aux spectroscopistes nucleaires pour l'etude des radiations {alpha}, {beta}, {gamma}. Leurs utilisations en radiochimie nous ont incite a en etudier le principe, le mecanisme et d'autre part les conditions d'emploi. La premiere partie, theorique, rappelle l'essentiel de ce qu'il est utile de connaitre pour une utilisation optimale des detecteurs a jonctions et en particulier des detecteurs Ge (Li). La deuxieme partie, experimentale, resume les travaux realises au laboratoire pendant un an avec des detecteurs Ge (Li). Nous insistons sur les possibilites offertes et les precautions a prendre dans l'utilisation de ces detecteurs comme spectrometres photoelectriques. Parmi les nombreux resultats presentes, citons la resolution de 2,52 keV obtenue pour le rayonnement {gamma} de 145 f5 keV du {sup 141}Ce. (auteurs)

  9. LHCb: LHCb Upstream Tracker

    CERN Multimedia

    Manning Jr, P; Stone, S

    2014-01-01

    The LHCb upgrade requires replacing the silicon strip tracker between the vertex locator and the magnet. A new design has been developed and tested based on the "stave" concept planned for the ATLAS upgrade. We will describe the new detector being constructed and show its improved performance in charged particle tracking and triggering.

  10. Mesure de la Polarisation des Lambda Produits dans les Collisions Positron-Electron AU Lep a L'aide du Detecteur Opal

    Science.gov (United States)

    Vandenplas, Denis

    Le Modele Standard est le cadre theorique general qui, jusqu'a present, a permis l'interpretation de tous les resultats experimentaux en physique des hautes energies. Cette theorie decrit, entre autres, la production d'une paire de particules elementaires, formee d'un quark et d'un antiquark, a partir de la desintegration de l'un des bosons mediateurs de l'interaction faible, le Z^0. Cependant, dans ce cas precis, la transformation subsequente des quarks primaires en particules reelles, un processus appele hadronisation, n'est decrite qu'a l'aide de modeles phenomenologiques. Afin de sonder les mecanismes de l'hadronisation, cette these presente la mesure du transfert du spin d'un quark etrange primaire a une particule appelee Lambda lors des desintegrations hadroniques du Z^0. L'etude a ete realisee dans le cadre de la collaboration OPAL, une des quatre experiences menees au collisionneur LEP, la ou des electrons et des positrons sont acceleres jusqu'a une energie commune, sqrt{s} = {rm E_ {cm}}, voisine de l'energie de production du rm Z^0, M_{Z ^0} egale a 91.3 GeV. La theorie electrofaible precise la direction du spin, c'est-a-dire la polarisation, d'un quark etrange primaire provenant de la desintegration d'un Z ^0. Quant a lui, le modele des quarks etablit que l'orientation du spin d'un Lambda est directement reliee a la polarisation du quark etrange dont il provient. La question est de determiner dans quelle mesure la polarisation du quark primaire est transmise au Lambda a la suite du processus de l'hadronisation, decrit dans le cadre de la ChromoDynamique Quantique. Une estimation, qui tient compte de tous ces differents aspects theoriques, evalue a 30% la polarisation des Lambda dont l'impulsion est superieure a 15 GeV/c. La mesure experimentale de la polarisation repose sur l'identification des Lambda a partir de la reconstitution de la desintegration Lambdato ppi^-. Ce processus, qui se deroule par le biais de l'interaction faible, viole la parite car

  11. LHCb; LHCb Jet Reconstruction

    CERN Multimedia

    Augusto, O

    2012-01-01

    The Large Hadron Collider (LHC) is the most powerful particle accelerator in the world. It has been designed to collide proton beams at an energy up to 14 TeV in the center of mass. In 2011, the data taking was done with a center of mass energy of 7 TeV, the instant luminosity has reached values greater than $4 \\times 10^{32} cm^{-2} s^{-1}$ and the integrated luminosity reached the value of 1.02 $fb^{-1}$ on the LHCb. The jet reconstruction is fundamental to observe events that can be used to test pertubative QCD (pQCD). It also provides a way to observe standard model channels and searches for new physics like SUSY. The anti-kt algorithm is a jet reconstruction algorithm that is based on the distance of the particles on the space $\\eta \\times \\phi$ and on the transverse momentum of particles. To maximize the energy resolution all information about the trackers and the calo...

  12. LHCb: Quarkonium Production at LHCb

    CERN Multimedia

    Frosini, M

    2011-01-01

    Despite large experimental and theoretical efforts, quarkonium production in hadronic collisions is not yet satisfactorily understood. Due to its forward geometry, LHCb has the unique opportunity to explore the field of quarkonium production at high rapidity, thus exploring new and unknown territory. We report he measurement of the double differential $J/\\psi, \\psi (2S)$ and $\\Upsilon$ cross section at LHCb with the data sample recorded by the LHCb experiment during the 2010 data taking. The $J/\\psi$ and $\\psi (2S)$ prompt components are separated from the products of b-hadrons decays using topological information. The results are compared with several theoretical models and other experiments. Preliminary results and prospects for the other quarkonium states will also be given.

  13. Contribution to the study of radio toxicity of aromatic and medicinal plants using solid state nuclear track detectors; Contribution a l etude de la radio toxicite des plantes aromatiques et medicinales au moyen des detecteurs solides de traces nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Mortassim, A; Misdaq, M A; Naaman, A

    2009-07-01

    The concentrations of uranium (238 U), thorium (232 Th), radon (222 Rn) and thoron (220 Rn) were measured in twenty aromatic and medicinal plants in {sup f}ind a new method based on using solid state nuclear track detectors type Cr-39 and Rs-115. He emerges from this study that the verbena and salvia have higher levels of uranium (radon) higher than that of other plants while the leaves of olive and saturja have concentrations of thorium (thoron) higher than other plants therefore radio toxicity of these plants is higher than that of others and may pose a radiological hazard if the masses are incorporated by consumers high. [French] Les concentrations en uranium (238U), thorium (232Th), radon (222Rn), et thoron (220Rn) ont ete mesurees dans vingt plantes aromatiques et medicinales en utilsant une nouvelle methode basee sur l utilisation des detecteurs solides de traces nucleaires de types CR-39 et LR-115. Il en sort de cette etude que la verveine et la salvia presentent des teneurs en uranium (radon) superieurs a celle des autres plantes alors que les feuilles d olivier et la saturja presentent des concentrations en thorium (thoron) plus elevee que celles des autres plantes par consequent la radio toxicite de ces plantes est superieure a celles des autres et peuvent presenter un risque radiologique si les masses incorporees par les consommateurs sont elevees.

  14. LHCB : Exotic hadrons at LHCb

    CERN Multimedia

    Salazar De Paula, Leandro

    2015-01-01

    The latest years have seen a resurrection of interest in searches for exotic states motivated by tantalising observations by Belle and CDF. Using the data collected at pp collisions at 7 and 8 TeV by the LHCb experiment we present the unambiguous new observation of exotic charmonia hadrons produced in B decays.

  15. Study of the heavy ions (Au+Au at 150 AMeV) collisions with the FOPI detector. Comparison with the Landau-Vlasov model; Etude des collisions d`ions lourds AU+AU a 150 A.MeV avec le detecteur FOPI. Comparaison avec le modele de Landau-Vlasov

    Energy Technology Data Exchange (ETDEWEB)

    Boussange, S

    1995-09-15

    In this thesis, heavy ions (Au+Au) collisions experiments are made at 150 AMeV.In the first part, a general study of the nuclear matter equation is presented. Then the used Landau-Vlasov theoretical model is describe. The third part presents the FOPI experience and the details of how to obtain this theoretical predictions (filter, cuts, corrections, possible centrality selections).At the end, experimental results and comparisons with the Landau-Vlasov model are presented. (TEC). 105 refs., 96 figs., 14 tabs.

  16. LHCb: LHCb Distributed Computing Operations

    CERN Multimedia

    Stagni, F

    2011-01-01

    The proliferation of tools for monitoring both activities and infrastructure, together with the pressing need for prompt reaction in case of problems impacting data taking, data reconstruction, data reprocessing and user analysis brought to the need of better organizing the huge amount of information available. The monitoring system for the LHCb Grid Computing relies on many heterogeneous and independent sources of information offering different views for a better understanding of problems while an operations team and defined procedures have been put in place to handle them. This work summarizes the state-of-the-art of LHCb Grid operations emphasizing the reasons that brought to various choices and what are the tools currently in use to run our daily activities. We highlight the most common problems experienced across years of activities on the WLCG infrastructure, the services with their criticality, the procedures in place, the relevant metrics and the tools available and the ones still missing.

  17. LHCb: Electroweak studies at LHCb

    CERN Multimedia

    Salustino Guimaraes, V

    2012-01-01

    Results on the measurement of the $W^{\\pm}$ and $Z^{0}$ cross-sections are presented using final state leptons with pseudorapidities between 2 and 4.5. Due to its acceptance, LHCb can probe a regime of low low-x electroweak boson production, where parton distribution functions are not well constrained. We summarize the $W^{\\pm}$ measurements performed in the decay $\\mu^{\\pm}\

  18. LHCb : The LHCb Turbo stream

    CERN Multimedia

    Puig Navarro, Albert

    2015-01-01

    The LHCb experiment will record an unprecedented dataset of beauty and charm hadron decays during Run II of the LHC, set to take place between 2015 and 2018. A key computing challenge is to store and process this data, which limits the maximum output rate of the LHCb trigger. So far, LHCb has written out a few kHz of events containing the full raw sub-detector data, which are passed through a full offline event reconstruction before being considered for physics analysis. Charm physics in particular is limited by trigger output rate constraints. A new streaming strategy includes the possibility to perform the physics analysis with candidates reconstructed in the trigger, thus bypassing the offline reconstruction. In the "turbo stream" the trigger will write out a compact summary of "physics" objects containing all information necessary for analyses, and this will allow an increased output rate and thus higher average efficiencies and smaller selection biases. This idea will be commissioned and developed during...

  19. Distributed analysis at LHCb

    International Nuclear Information System (INIS)

    Williams, Mike; Egede, Ulrik; Paterson, Stuart

    2011-01-01

    The distributed analysis experience to date at LHCb has been positive: job success rates are high and wait times for high-priority jobs are low. LHCb users access the grid using the GANGA job-management package, while the LHCb virtual organization manages its resources using the DIRAC package. This clear division of labor has benefitted LHCb and its users greatly; it is a major reason why distributed analysis at LHCb has been so successful. The newly formed LHCb distributed analysis support team has also proved to be a success.

  20. LHCb on track

    CERN Document Server

    2006-01-01

    On 7 and 8 June 2006, the last large component of the LHCb experiment was lowered into the cavern. This 10-tonne, 18-metre long metal structure known as 'the bridge' will support the LHCb tracking system.

  1. LHCb: Radiative Decays at LHCb

    CERN Multimedia

    Orlandea, M

    2013-01-01

    In this work we present a measurement of the ratio of the branching fraction of the radiative decays $B^{0}\\rightarrow K^{*0}\\gamma$ and $B^{0}_{s}\\rightarrow \\phi\\gamma$ using 1.0 fb$^{-1}$ of data taken with the LHCb detector. The value obtained is \\begin{equation} \\frac{B\\left(B^{0}\\rightarrow K^{*0}\\gamma\\right)}{B\\left(B^{0}_{s}\\rightarrow \\phi\\gamma\\right)}=1.23\\pm0.06(stat.)\\pm0.04(syst.)\\pm0.10\\left(f_s/f_d\\right) \\end{equation} Using the world average value $B\\left(B^{0}\\rightarrow K^{*0}\\gamma\\right)=\\left(4.33\\pm0.15\\right)\\times10^{-5}$ branching fraction is determined to be $B\\left(B^{0}_{s}\\rightarrow \\phi\\gamma\\right)=3.5\\pm0.4\\times10^{-5}$. A measurement of the direct CP asymmetry of the decay $B^{0}\\rightarrow K^{*0}\\gamma$ is also presented. Both measurements are the most precise to date and are in agreement with the previous experimental results and theoretical expectations.

  2. CKM angle $\\gamma$ from LHCb

    CERN Multimedia

    Smith, Jackson

    2015-01-01

    Results of the latest $\\gamma$ combination from LHCb are presented, along with the six LHCb measurements used as inputs. In addition, the anticipated precision attainable for measuring $\\gamma$ after the LHCb Upgrade is outlined

  3. Effets de rayonnement sur les detecteurs au silicium a pixels du detecteur ATLAS

    CERN Document Server

    Lebel, Celine

    2007-01-01

    Two detection systems are using pixel silicon detectors in the ATLAS detector: the Pixel, which is the subdetector closest to the interaction point, and the MPX network. The activation of the materials present in the Pixel produced by radiation has been measured in two experiments which we performed at CERF (CERN) and NPI-ASCR (Czech Republic). These experimental studies of activation are com- pared with GEANT4 simulations. The results of these comparisons show that the simulation can predict the activities with a precision of an order of magnitude. They also show that GEANT4 fails to produce certain radioisotopes seen in the experimental activation studies. The contribution to background and the resid- ual doses due to the desintegration of the radioisotopes produced by fast neutrons (category in which falls the expected average neutron energy of 1 MeV in ATLAS) are extrapolated to ATLAS conditions. It is found that this background in the AT- LAS Pixel subdetector will be negligible and that the doses are we...

  4. Recent results from LHCb

    CERN Document Server

    Oblakowska-Mucha, A

    2016-01-01

    The LHCb detector is a single-arm forward spectrometer that collects data at the LHC. In this review, a few of recent results in the field of $b$-hadron decays performed by the LHCb Collaboration are presented. The analyses use proton-proton collision data corresponding to 3 fb$^{-1}$ collected by the LHCb detector during 2011 and 2012 physics runs with the center-of-mass energies of 7 and 8 TeV.

  5. LHCb Detector Performance

    CERN Document Server

    Aaij, Roel; Adinolfi, Marco; Affolder, Anthony; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Anderson, Jonathan; Andreassen, Rolf; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Aquines Gutierrez, Osvaldo; Archilli, Flavio; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Batozskaya, Varvara; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Belogurov, Sergey; Belous, Konstantin; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bien, Alexander; Bifani, Simone; Bird, Thomas; Bizzeti, Andrea; Bjørnstad, Pål Marius; Blake, Thomas; Blanc, Frédéric; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borghi, Silvia; Borgia, Alessandra; Borsato, Martino; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Brambach, Tobias; Bressieux, Joël; Brett, David; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Brook, Nicholas; Brown, Henry; Bursche, Albert; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Campana, Pierluigi; Campora Perez, Daniel; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu-Faye; Chiapolini, Nicola; Chrzaszcz, Marcin; Ciba, Krzystof; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coco, Victor; Cogan, Julien; Cogneras, Eric; Cogoni, Violetta; Cojocariu, Lucian; Collazuol, Gianmaria; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombes, Matthew; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Counts, Ian; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Crocombe, Andrew; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Dalseno, Jeremy; David, Pascal; David, Pieter; Davis, Adam; De Bruyn, Kristof; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Silva, Weeraddana; De Simone, Patrizia; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Déléage, Nicolas; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Di Canto, Angelo; Dijkstra, Hans; Donleavy, Stephanie; Dordei, Francesca; Dorigo, Mirco; Dosil Suárez, Alvaro; Dossett, David; Dovbnya, Anatoliy; Dreimanis, Karlis; Dujany, Giulio; Dupertuis, Frederic; Durante, Paolo; Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; Easo, Sajan; Egede, Ulrik; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; El Rifai, Ibrahim; Elsasser, Christian; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Färber, Christian; Farinelli, Chiara; Farley, Nathanael; Farry, Stephen; Fay, Robert; Ferguson, Dianne; Fernandez Albor, Victor; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fiore, Marco; Fiorini, Massimiliano; Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fol, Philip; Fontana, Marianna; Fontanelli, Flavio; Forty, Roger; Francisco, Oscar; Frank, Markus; Frei, Christoph; Frosini, Maddalena; Fu, Jinlin; Furfaro, Emiliano; Gallas Torreira, Abraham; Galli, Domenico; Gallorini, Stefano; Gambetta, Silvia; Gandelman, Miriam; Gandini, Paolo; Gao, Yuanning; García Pardiñas, Julián; Garofoli, Justin; Garra Tico, Jordi; Garrido, Lluis; Gascon, David; Gaspar, Clara; Gauld, Rhorry; Gavardi, Laura; Geraci, Angelo; Gersabeck, Evelina; Gersabeck, Marco; Gershon, Timothy; Ghez, Philippe; Gianelle, Alessio; Gianì, Sebastiana; Gibson, Valerie; Giubega, Lavinia-Helena; Gligorov, V.V.; Göbel, Carla; Golubkov, Dmitry; Golutvin, Andrey; Gomes, Alvaro; Gotti, Claudio; Grabalosa Gándara, Marc; Graciani Diaz, Ricardo; Granado Cardoso, Luis Alberto; Graugés, Eugeni; Graverini, Elena; Graziani, Giacomo; Grecu, Alexandru; Greening, Edward; Gregson, Sam; Griffith, Peter; Grillo, Lucia; Grünberg, Oliver; Gui, Bin; Gushchin, Evgeny; Guz, Yury; Gys, Thierry; Hadjivasiliou, Christos; Haefeli, Guido; Haen, Christophe; Haines, Susan; Hall, Samuel; Hamilton, Brian; Hampson, Thomas; Han, Xiaoxue; Hansmann-Menzemer, Stephanie; Harnew, Neville; Harnew, Samuel; Harrison, Jonathan; He, Jibo; Head, Timothy; Heijne, Veerle; Hennessy, Karol; Henrard, Pierre; Henry, Louis; Hernando Morata, Jose Angel; van Herwijnen, Eric; Heß, Miriam; Hicheur, Adlène; Hill, Donal; Hoballah, Mostafa; Hombach, Christoph; Hulsbergen, Wouter; Hunt, Philip; Hussain, Nazim; Hutchcroft, David; Hynds, Daniel; Idzik, Marek; Ilten, Philip; Jacobsson, Richard; Jaeger, Andreas; Jalocha, Pawel; Jans, Eddy; Jaton, Pierre; Jawahery, Abolhassan; Jing, Fanfan; John, Malcolm; Johnson, Daniel; Jones, Christopher; Joram, Christian; Jost, Beat; Jurik, Nathan; Kandybei, Sergii; Kanso, Walaa; Karacson, Matthias; Karbach, Moritz; Karodia, Sarah; Kelsey, Matthew; Kenyon, Ian; Ketel, Tjeerd; Khanji, Basem; Khurewathanakul, Chitsanu; Klaver, Suzanne; Klimaszewski, Konrad; Kochebina, Olga; Kolpin, Michael; Komarov, Ilya; Koopman, Rose; Koppenburg, Patrick; Korolev, Mikhail; Kozlinskiy, Alexandr; Kravchuk, Leonid; Kreplin, Katharina; Kreps, Michal; Krocker, Georg; Krokovny, Pavel; Kruse, Florian; Kucewicz, Wojciech; Kucharczyk, Marcin; Kudryavtsev, Vasily; Kurek, Krzysztof; Kvaratskheliya, Tengiz; La Thi, Viet Nga; Lacarrere, Daniel; Lafferty, George; Lai, Adriano; Lambert, Dean; Lambert, Robert W; Lanfranchi, Gaia; Langenbruch, Christoph; Langhans, Benedikt; Latham, Thomas; Lazzeroni, Cristina; Le Gac, Renaud; van Leerdam, Jeroen; Lees, Jean-Pierre; Lefèvre, Regis; Leflat, Alexander; Lefrançois, Jacques; Leo, Sabato; Leroy, Olivier; Lesiak, Tadeusz; Leverington, Blake; Li, Yiming; Likhomanenko, Tatiana; Liles, Myfanwy; Lindner, Rolf; Linn, Christian; Lionetto, Federica; Liu, Bo; Lohn, Stefan; Longstaff, Iain; Lopes, Jose; Lopez-March, Neus; Lowdon, Peter; Lucchesi, Donatella; Luo, Haofei; Lupato, Anna; Luppi, Eleonora; Lupton, Oliver; Machefert, Frederic; Machikhiliyan, Irina V; Maciuc, Florin; Maev, Oleg; Malde, Sneha; Malinin, Alexander; Manca, Giulia; Mancinelli, Giampiero; Mapelli, Alessandro; Maratas, Jan; Marchand, Jean François; Marconi, Umberto; Marin Benito, Carla; Marino, Pietro; Märki, Raphael; Marks, Jörg; Martellotti, Giuseppe; Martens, Aurelien; Martín Sánchez, Alexandra; Martinelli, Maurizio; Martinez Santos, Diego; Martinez Vidal, Fernando; Martins Tostes, Danielle; Massafferri, André; Matev, Rosen; Mathe, Zoltan; Matteuzzi, Clara; Mazurov, Alexander; McCann, Michael; McCarthy, James; McNab, Andrew; McNulty, Ronan; McSkelly, Ben; Meadows, Brian; Meier, Frank; Meissner, Marco; Merk, Marcel; Milanes, Diego Alejandro; Minard, Marie-Noelle; Moggi, Niccolò; Molina Rodriguez, Josue; Monteil, Stephane; Morandin, Mauro; Morawski, Piotr; Mordà, Alessandro; Morello, Michael Joseph; Moron, Jakub; Morris, Adam Benjamin; Mountain, Raymond; Muheim, Franz; Müller, Katharina; Mussini, Manuel; Muster, Bastien; Naik, Paras; Nakada, Tatsuya; Nandakumar, Raja; Nasteva, Irina; Needham, Matthew; Neri, Nicola; Neubert, Sebastian; Neufeld, Niko; Neuner, Max; Nguyen, Anh Duc; Nguyen, Thi-Dung; Nguyen-Mau, Chung; Nicol, Michelle; Niess, Valentin; Niet, Ramon; Nikitin, Nikolay; Nikodem, Thomas; Novoselov, Alexey; O'Hanlon, Daniel Patrick; Oblakowska-Mucha, Agnieszka; Obraztsov, Vladimir; Oggero, Serena; Ogilvy, Stephen; Okhrimenko, Oleksandr; Oldeman, Rudolf; Onderwater, Gerco; Orlandea, Marius; Otalora Goicochea, Juan Martin; Owen, Patrick; Oyanguren, Maria Arantza; Pal, Bilas Kanti; Palano, Antimo; Palombo, Fernando; Palutan, Matteo; Panman, Jacob; Papanestis, Antonios; Pappagallo, Marco; Pappalardo, Luciano; Parkes, Christopher; Parkinson, Christopher John; Passaleva, Giovanni; Patel, Girish; Patel, Mitesh; Patrignani, Claudia; Pearce, Alex; Pellegrino, Antonio; Penso, Gianni; Pepe Altarelli, Monica; Perazzini, Stefano; Perret, Pascal; Perrin-Terrin, Mathieu; Pescatore, Luca; Pesen, Erhan; Pessina, Gianluigi; Petridis, Konstantin; Petrolini, Alessandro; Picatoste Olloqui, Eduardo; Pietrzyk, Boleslaw; Pilař, Tomas; Pinci, Davide; Pistone, Alessandro; Playfer, Stephen; Plo Casasus, Maximo; Polci, Francesco; Poluektov, Anton; Polyakov, Ivan; Polycarpo, Erica; Popov, Alexander; Popov, Dmitry; Popovici, Bogdan; Potterat, Cédric; Price, Eugenia; Price, Joseph David; Prisciandaro, Jessica; Pritchard, Adrian; Prouve, Claire; Pugatch, Valery; Puig Navarro, Albert; Punzi, Giovanni; Qian, Wenbin; Rachwal, Bartolomiej; Rademacker, Jonas; Rakotomiaramanana, Barinjaka; Rama, Matteo; Rangel, Murilo; Raniuk, Iurii; Rauschmayr, Nathalie; Raven, Gerhard; Redi, Federico; Reichert, Stefanie; Reid, Matthew; dos Reis, Alberto; Ricciardi, Stefania; Richards, Sophie; Rihl, Mariana; Rinnert, Kurt; Rives Molina, Vincente; Robbe, Patrick; Rodrigues, Ana Barbara; Rodrigues, Eduardo; Rodriguez Perez, Pablo; Roiser, Stefan; Romanovsky, Vladimir; Romero Vidal, Antonio; Rotondo, Marcello; Rouvinet, Julien; Ruf, Thomas; Ruiz, Hugo; Ruiz Valls, Pablo; Saborido Silva, Juan Jose; Sagidova, Naylya; Sail, Paul; Saitta, Biagio; Salustino Guimaraes, Valdir; Sanchez Mayordomo, Carlos; Sanmartin Sedes, Brais; Santacesaria, Roberta; Santamarina Rios, Cibran; Santovetti, Emanuele; Sarti, Alessio; Satriano, Celestina; Satta, Alessia; Saunders, Daniel Martin; Savrina, Darya; Schiller, Manuel; Schindler, Heinrich; Schlupp, Maximilian; Schmelling, Michael; Schmidt, Burkhard; Schneider, Olivier; Schopper, Andreas; Schune, Marie Helene; Schwemmer, Rainer; Sciascia, Barbara; Sciubba, Adalberto; Semennikov, Alexander; Sepp, Indrek; Serra, Nicola; Serrano, Justine; Sestini, Lorenzo; Seyfert, Paul; Shapkin, Mikhail; Shapoval, Illya; Shcheglov, Yury; Shears, Tara; Shekhtman, Lev; Shevchenko, Vladimir; Shires, Alexander; Silva Coutinho, Rafael; Simi, Gabriele; Sirendi, Marek; Skidmore, Nicola; Skillicorn, Ian; Skwarnicki, Tomasz; Smith, Anthony; Smith, Edmund; Smith, Eluned; Smith, Jackson; Smith, Mark; Snoek, Hella; Sokoloff, Michael; Soler, Paul; Soomro, Fatima; Souza, Daniel; Souza De Paula, Bruno; Spaan, Bernhard; Sparkes, Ailsa; Spradlin, Patrick; Sridharan, Srikanth; Stagni, Federico; Stahl, Marian; Stahl, Sascha; Steinkamp, Olaf; Stenyakin, Oleg; Stevenson, Scott; Stoica, Sabin; Stone, Sheldon; Storaci, Barbara; Stracka, Simone; Straticiuc, Mihai; Straumann, Ulrich; Stroili, Roberto; Subbiah, Vijay Kartik; Sun, Liang; Sutcliffe, William; Swientek, Krzysztof; Swientek, Stefan; Syropoulos, Vasileios; Szczekowski, Marek; Szczypka, Paul; Szumlak, Tomasz; T'Jampens, Stephane; Teklishyn, Maksym; Tellarini, Giulia; Teubert, Frederic; Thomas, Christopher; Thomas, Eric; van Tilburg, Jeroen; Tisserand, Vincent; Tobin, Mark; Tolk, Siim; Tomassetti, Luca; Tonelli, Diego; Topp-Joergensen, Stig; Torr, Nicholas; Tournefier, Edwige; Tourneur, Stephane; Tran, Minh Tâm; Tresch, Marco; Tsaregorodtsev, Andrei; Tsopelas, Panagiotis; Tuning, Niels; Ubeda Garcia, Mario; Ukleja, Artur; Ustyuzhanin, Andrey; Uwer, Ulrich; Vacca, Claudia; Vagnoni, Vincenzo; Valenti, Giovanni; Vallier, Alexis; Vazquez Gomez, Ricardo; Vazquez Regueiro, Pablo; Vázquez Sierra, Carlos; Vecchi, Stefania; Velthuis, Jaap; Veltri, Michele; Veneziano, Giovanni; Vesterinen, Mika; Viaud, Benoit; Vieira, Daniel; Vieites Diaz, Maria; Vilasis-Cardona, Xavier; Vollhardt, Achim; Volyanskyy, Dmytro; Voong, David; Vorobyev, Alexey; Vorobyev, Vitaly; Voß, Christian; de Vries, Jacco; Waldi, Roland; Wallace, Charlotte; Wallace, Ronan; Walsh, John; Wandernoth, Sebastian; Wang, Jianchun; Ward, David; Watson, Nigel; Websdale, David; Whitehead, Mark; Wicht, Jean; Wiedner, Dirk; Wilkinson, Guy; Williams, Matthew; Williams, Mike; Wilschut, Hans; Wilson, Fergus; Wimberley, Jack; Wishahi, Julian; Wislicki, Wojciech; Witek, Mariusz; Wormser, Guy; Wotton, Stephen; Wright, Simon; Wyllie, Kenneth; Xie, Yuehong; Xing, Zhou; Xu, Zhirui; Yang, Zhenwei; Yuan, Xuhao; Yushchenko, Oleg; Zangoli, Maria; Zavertyaev, Mikhail; Zhang, Liming; Zhang, Wen Chao; Zhang, Yanxi; Zhelezov, Alexey; Zhokhov, Anatoly; Zhong, Liang; Zvyagin, Alexander

    2015-03-05

    The LHCb detector is a forward spectrometer at the Large Hadron Collider (LHC) at CERN. The experiment is designed for precision measurements of CP violation and rare decays of beauty and charm hadrons. In this paper the performance of the various LHCb sub-detectors and the trigger system are described, using data taken from 2010 to 2012. It is shown that the design criteria of the experiment have been met. The excellent performance of the detector has allowed the LHCb collaboration to publish a wide range of physics results, demonstrating LHCb's unique role, both as a heavy flavour experiment and as a general purpose detector in the forward region.

  6. LHCb brochure (French version)

    CERN Multimedia

    Marcastel, Fabienne

    2014-01-01

    LHCb is one of the four big experiments for the LHC, the most powerful particle accelerator in the world, which will start up in 2008. LHCb studies a phenomenon which could partly explain why the Universe is all matter and practically no antimatter.

  7. LHCb brochure (English version)

    CERN Multimedia

    Marcastel, Fabienne

    2014-01-01

    LHCb is one of the four big experiments for the LHC, the most powerful particle accelerator in the world, which will start up in 2008. LHCb studies a phenomenon which could partly explain why the Universe is all matter and practically no antimatter.

  8. LHCb brochure (Italian version)

    CERN Multimedia

    Marcastel, Fabienne

    2014-01-01

    LHCb is one of the four big experiments for the LHC, the most powerful particle accelerator in the world, which will start up in 2008. LHCb studies a phenomenon which could partly explain why the Universe is all matter and practically no antimatter.

  9. LHCb brochure (German version)

    CERN Multimedia

    Lefevre, Christiane

    2012-01-01

    LHCb is one of the four big experiments for the LHC, the most powerful particle accelerator in the world, which will start up in 2008. LHCb will study a phenomenon which could partly explain why the Universe is all matter and practically no antimatter.

  10. LHCb brochure (German version)

    CERN Multimedia

    Lefevre, C

    2008-01-01

    LHCb is one of the four big experiments for the LHC, the most powerful particle accelerator in the world, which will start up in 2008. LHCb will study a phenomenon which could partly explain why the Universe is all matter and practically no antimatter.

  11. The LHCb magnet

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    The LHCb magnet consists of two huge 27 tonne coils mounted inside a 1450 tonne iron yoke. As charged particles pass through the magnet's field their trajectories will be bent according to their momentum, allowing their momentum to be measured as they pass through the detector walls. LHCb will study bottom quarks, which will be produced close to the two colliding proton beams.

  12. LHCb detector performance

    NARCIS (Netherlands)

    Aaij, R.; Adeva, B.; Adinol, M.; Affolder, A.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Alvarez Cartelle, P.; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Anderson, J.; Andreassen, R.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Gutierrez, O. Aquines; Archilli, F.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Bachmann, S.; Back, J. J.; Badalov, A.; Baesso, C.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Batozskaya, V.; Battista, V.; Bay, A.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Belogurov, S.; Onderwater, C. J. G.; Pellegrino, A.; Wilschut, H. W.

    2015-01-01

    The LHCb detector is a forward spectrometer at the Large Hadron Collider (LHC) at CERN. The experiment is designed for precision measurements of CP violation and rare decays of beauty and charm hadrons. In this paper the performance of the various LHCb sub-detectors and the trigger system are

  13. LHCb brochure (Spanish version)

    CERN Multimedia

    Lefevre, C

    2008-01-01

    LHCb is one of the four big experiments for the LHC, the most powerful particle accelerator in the world, which will start up in 2008. LHCb will study a phenomenon which could partly explain why the Universe is all matter and practically no antimatter.

  14. The LHCb trigger

    CERN Document Server

    Hernando Morata, Jose Angel

    2006-01-01

    The LHCb experiment relies on an efficient trigger to select a rate up to 2 kHz of events useful for physics analysis from an initial rate of 10 MHz of visible collisions. In this contribution, we describe the different LHCb trigger algorithms and present their expected performance.

  15. LHCb: LHCb VELO TELL1 Algorithms

    CERN Multimedia

    Hennessy, Karol

    2012-01-01

    The LHCb experiment is dedicated to searching for New Physics effects in the heavy flavour sector, precise measurements of CP violation and rare heavy meson decays. Precise tracking and vertexing around the interaction point is crucial in achieving these physics goals. The LHCb VELO (VErtex LOcator) silicon micro-strip detector is the highest precision vertex detector at the LHC and is located at only 8 mm from the proton beams. The high spatial resolution (up to 4 microns single hit precision) is obtained by a complex chain of processing algorithms to suppress noise and reconstruct clusters. These are implemented in large FPGAs, with over one million parameters that need to be individually optimised. Previously we presented a novel approach that has been developed to optimise the parameters and integrating their determination into the full software framework of the LHCb experiment. Presently we report on the experience gained from regular operation of the calibration and monitoring software with the collisio...

  16. LHCb: The LHCb data bookkeeping system

    CERN Multimedia

    Lanciotti, E

    2009-01-01

    The LHCb Bookkeeping is a system for the storage and retrieval of meta data associated with LHCb datasets. e.g. whether it is real or simulated data, which running period it is associated with, how it was processed and all the other relevant characteristics of the files. etc. The meta data is stored in an oracle database which is interrogated using services provided by the LHCb DIRAC3 infrastructure, that provides security, data streaming, and multi threading connections. Users can browse the bookkeeping database through a command line interface or Graphical User Interface (GUI). The command line presents a view similar to a file system and the GUI is implemented on top of this.

  17. LHCb: W and Z production at LHCb

    CERN Multimedia

    Barter, W

    2011-01-01

    Preliminary results are presented for the production cross-sections of $Z^0$ and $W^{\\pm}$ production at the LHCb experiment. Also shown is the $W$ charge asymmetry as a function of lepton pseudo-rapidity. These measurements have particular interest because of the forward acceptance of the LHCb experiment, which covers pseudo-rapidities between approximately 2 and 5. The results may be interpreted as tests of the Standard Model, or can be used to constrain better the parton density functions. Prospects are given for improving these measurements in the forthcoming run, and for making complementary studies of Drell-Yan production to lower mass dilepton final states.

  18. LHCb: The LHCb Silicon Tracker: Running experience

    CERN Multimedia

    Saornil Gamarra, S

    2012-01-01

    The LHCb Silicon Tracker is part of the main tracking system of the LHCb detector at the LHC. It measures very precisely the particle trajectories coming from the interaction point in the region of high occupancies around the beam axis. After presenting our production and comissioning issues in TWEPP 2008, we report on our running experience. Focusing on electronic and hardware issues as well as operation and maintenance adversities, we describe the lessons learned and the pitfalls encountered after three years of successful operation.

  19. A spectrometer using semi-conductor detectors; study and applications (1963); Spectrometre utilisant les detecteurs a semi-conducteur: etudes et applications (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Roux, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    The low average energy, 2.5 to 3.5 eV, required to produce one hole-electron pair in a semiconductor allows an accurate measurement of the energy of the ionizing particles. A high resolution spectrometer has been built using semiconductor detectors. The limit of resolution, due to electronics associated to the detector, to the detector itself and to the source of particles is studied here. The present practical limit of resolution of the spectrometer is 1700 elementary electric charges (full width at half maximum of a ray of a spectrum) or 6 keV in terms of energy lost by a particle in a silicon detector. The physical resolution usually obtained is 20 keV (0.33 per cent) with {alpha} particles of the {sup 212}Bi (6.087 MeV). It depends a lot of the kind of detector used. Some results, concerning the background of the detectors and limit of measurements for low energies are given. Various applications are presented: spectrometry {beta}, spectrometry {gamma} and X, spectrometry of mixtures of {alpha} radioactive elements, collection of {alpha} spectra. (author) [French] La faible energie moyenne, 2,5 a 3,5 eV, necessaire pour produire une paire electron-trou dans un semi-conducteur, permet une mesure precise de l'energie des particules ionisantes. Un spectrometre a haute resolution a ete construit utilisant des detecteurs a semi-conducteur. La limitation en resolution due a l'electronique associee au detecteur, au detecteur lui-meme et a la source de particules, est etudiee. La resolution pratique limite actuelle du spectrometre est 1700 charges electriques elementaires (largeur a mi-hauteur d'une raie de spectre) ou 6 keV exprimee en energie perdue par une particule dans un detecteur au silicium. La resolution physique couramment obtenue est de 20 keV (0,33 pour cent) pour les particules {alpha} du bismuth 212 (6,087 MeV). Elle depend beaucoup du detecteur utilise. Quelques resultats sont donnes concernant le mouvement propre des detecteurs et la limitation des

  20. LHCb: Exotic meson studies at LHCb

    CERN Multimedia

    Bressieux, Joël

    2012-01-01

    In this poster, we present the narrow $J/\\psi\\phi$ resonances X(4140) and X(4274) search as well as the X(3872) mass and productions cross-section measurements. These analysis have been done using pp collisions data collected at LHCb.

  1. LHCb: Physics with the LHCb calorimeter

    CERN Multimedia

    Barsuk, S

    2007-01-01

    The LHCb calorimeter comprises the scintillator pad detector (SPD), preshower (PS), electromagnetic Shashlyk type (ECAL) and hadronichadronic Tile (HCAL) calorimeters, arranged in pseudo-projective geometry. All the four detectors follow the general principle of reading the light from scintillator tiles with wave length shifting fibers, and transporting the light towards photomultipliers (25 ns R/O).

  2. LHCb Upstream Tracker

    CERN Multimedia

    Gandini, Paolo

    2014-01-01

    The LHCb upgrade requires replacing the silicon strip tracker between the vertex locator (VELO) and the magnet. A new design has been developed and tested based on the "stave" concept planned for the ATLAS upgrade.

  3. LHCb Upstream Tracker

    CERN Multimedia

    Gandini, P

    2014-01-01

    The LHCb upgrade requires replacing the silicon strip tracker between the vertex locator (VELO) and the magnet. A new design has been developed and tested based on the "stave" concept planned for the ATLAS upgrade

  4. LHCb launches new website

    CERN Multimedia

    2008-01-01

    A new public website for the LHCb experiment was launched last Friday to coincide with CERN’s Open Day weekend. Designed to provide accessible information on all aspects of the experiment, the website contains images and key facts about the LHCb detector, its design and installation and the international team behind the project. "LHCb is going to be one of the most important b-physics experiments in the world when it starts taking data later this year", explains Roger Forty, the experiment’s deputy spokesperson. "We hope the website will be a valuable resource, enabling people to learn about this fascinating area of research." The new website can be found at: http://cern.ch/lhcb-public

  5. LHCb: LHCbDirac is a DIRAC extension to support LHCb specific workflows

    CERN Multimedia

    Stagni, Federico

    2012-01-01

    We present LHCbDIRAC, an extension of the DIRAC community Grid solution to handle the LHCb specificities. The DIRAC software has been developed for many years within LHCb only. Nowadays it is a generic software, used by many scientific communities worldwide. Each community wanting to take advantage of DIRAC has to develop an extension, containing all the necessary code for handling their specific cases. LHCbDIRAC is an actively developed extension, implementing the LHCb computing model and workflows. LHCbDIRAC extends DIRAC to handle all the distributed computing activities of LHCb. Such activities include real data processing (reconstruction, stripping and streaming), Monte-Carlo simulation and data replication. Other activities are groups and user analysis, data management, resources management and monitoring, data provenance, accounting for user and production jobs. LHCbDIRAC also provides extensions of the DIRAC interfaces, including a secure web client, python APIs and CLIs. While DIRAC and LHCbDIRAC f...

  6. The LHCb Upgrade

    CERN Document Server

    Jacobsson, R

    2013-01-01

    With the demonstration that LHCb can successfully perform forward precision measurements with event pileup, the operation and trigger strategy evolved significantly during the LHC Run 1 allowing LHCb to collect over 3fb$^{-1}$ at centre-of-mass energies of 7TeV and 8TeV. Increased bandwidth opened the door for LHCb to extend the physics program. The additional statistics and well managed systematic effects together with the stable trigger and data taking conditions have led to a very large number of world-class measurements and dominance in heavy flavour physics [1], in addition to a reputation of an excellent forward general purpose detector at the LHC. Long Shutdown (LS) 1 (2013-2014) will allow LHCb to fully explore the large statistics collected and prepare LHCb for Run 2 (2015 – 2017). However, even after an additional expected integrated luminosity of 5-6 fb$^{-1}$ in Run 2, many of the LHCb precision measurements will remain limited by statistics, and some exploratory physics modes will not even be a...

  7. LHCb: The LHCb tracking concept and performance

    CERN Multimedia

    Rodrigues, E

    2009-01-01

    The LHCb tracking system is designed to reconstruct charged particle trajectories in the forward spectrometer, in view of high precision studies of CP-violating phenomena and searches for rare b-hadron decays at the LHC. The system is composed of four major subdetectors and a dedicated magnet, providing an excellent momentum resolution just above 0.4%. The tracking model is based on the innovative trajectories concept introduced by the BaBar collaboration to reconstruct and fit the tracks, and has been further developed and improved. It is now able to cope with realistic geometries and misalignments in a sophisticated, robust and detector-independent way. The LHCb tracking concept including the interplay of various complementary pattern recognition algorithms and the bi-directional Kalman fitter will be described. The current performance of the tracking, based on the latest simulations, will be presented. Recent results obtained with the first LHC beam tracks from injection tests will be discussed.

  8. LHCb: Improvements in the LHCb DAQ

    CERN Multimedia

    Campora, D; Schwemmer, R

    2014-01-01

    The LHCb data acquisition system is realized as a Gigabit Ethernet local area network with more than 330 FPGA driven data-sources, two core-routers, 56 fan-out switches and more than 1400 servers (will be upgraded to about 1800 soon). In total there are almost 3000 switch-ports. Data are pushed top-down, quasi-synchronously using n unreliable datagram protocol (like UDP).

  9. LHCb: A GPU offloading mechanism for LHCb

    CERN Multimedia

    Badalov, A; Zvyagin, A; Neufeld, N; Vilasis Cardona, X

    2013-01-01

    The LHCb Software Infrastructure is built around a flexible, extensible, single-process, single-threaded framework named Gaudi. One way to optimise the overall usage of a multi-core server, which is used for example in the Online world, is running multiple instances of Gaudi-based applications concurrently. For LHCb, this solution has been shown to work well up to 32 cores and is expected to scale up a bit further. The appearance of many-core architectures such as GPGPUs and the Intel Xeon/Phi poses a new challenge for LHCb. Since the individual data sets are so small (about 60 kB raw event size), many events must be processed in parallel for optimum efficiency. This is, however, not possible with the current framework, which allows only a single event at a time. Exploiting the fact that we always have many instances of the same application running, we have developed an offloading mechanism, based on a client-server design. The server runs outside the Gaudi framework and thus imposes no additional dependencie...

  10. Particle ID in LHCb

    International Nuclear Information System (INIS)

    Powell, Andrew

    2010-01-01

    Particle identification (PID) is a fundamental requirement for LHCb and is provided by CALO, MUON and RICH sub-detectors. The Calorimeters provide identification of electrons, photons and hadrons in addition to the measurement of their energies and positions. As well as being part of the LHCb trigger, the MUON system provides identification of muons to a very high level of purity, essential for many CP-sensitive measurements that have J/ψ's in their final states. Hadron identification, in particular the ability to distinguish kaons and pions, is crucial to many LHCB analyses, particularly where the final states of interest are purely hadronic. The LHCb RICH system provides this, covering a momentum range between 1 and 100 GeV/c. To maintain the integrity of the LHCb physics performance, it is essential to measure and monitor the particle identification efficiency and mis-identification fraction over time. This can be done by using specific decays, such as K-shorts, φ's, Λ's, J/ψ's and D*'s, for which pure samples can be isolated using only kinematic quantities, due to their unique decay topologies. This allows for clean samples of known particle types to be selected, which can then be used to calibrate and monitor the PID performance from data. The procedures for performing this will be presented, together with preliminary results from the 2009 and 2010 LHC runs. (author)

  11. Job prioritization in LHCb

    CERN Document Server

    Castellani, G

    2007-01-01

    LHCb is one of the four high-energy experiments running in the near future at the Large Hadron Collider (LHC) at CERN. LHCb will try to answer some fundamental questions about the asymmetry between matter and anti-matter. The experiment is expected to produce about 2PB of data per year. Those will be distributed to several laboratories all over Europe and then analyzed by the Physics community. To achieve this target LHCb fully uses the Grid to reprocess, replicate and analyze data. The access to the Grid happens through LHCb's own distributed production and analysis system, DIRAC (Distributed Infrastructure with Remote Agent Control). Dirac implements the ‘pull’ job scheduling paradigm, where all the jobs are stored in a central task queues and then pulled via generic grid jobs called Pilot Agents. The whole LHCb community (about 600 people) is divided in sets of physicists, developers, production and software managers that have different needs about their jobs on the Grid. While a Monte Carlo simulation...

  12. LHCb unveils new particles

    CERN Multimedia

    Stefania Pandolfi

    2016-01-01

    The LHCb collaboration announces the observation of four “exotic” particles from its analysis of the LHC data.   The LHCb experimental cavern. On 28 June, the LHCb collaboration reported the observation of three new "exotic" particles and confirmation of the existence of a fourth one in data from the LHC. These particles each appear to be formed by four quarks (the fundamental constituents of the matter inside all the atoms of the universe): two quarks and two antiquarks (that is, a tetraquark). Due to their non-standard quark content, the newly observed particles have been included in the broad category of so-called exotic particles, although their exact theoretical interpretation is still under study.            The quark model, proposed by Murray Gell-Mann and George Zweig in 1964, is considered to be the most valid scheme for the classification of hadrons (all the composite particles) that has been fou...

  13. The Latest from LHCb

    CERN Multimedia

    2009-01-01

    This month the LHCb Collaboration has observed the first Cherenkov rings from the RICH1 detector. These rings were emitted by cosmic particles passing through the detector. Cherenkov radiation occurs when a charged particle passes through a medium faster than the speed of light. As it travels, the particle emits photons along a cone. This cone is measured and, along with a measurement of momentum, is used to identify the particle. There are two types of radiators in RICH1, the first gaseous and the other made from aerogel. Both rings seen on the picture are from the same particle passing through the two different radiators. This is the fist time that the RICH detector has seen a particle as it will see them when the LHC re-starts. It has also been a time for the experiment to begin commissioning. After network upgrades, LHCb held a commissioning week, an opportunity for physicists working on all the different detectors within LHCb...

  14. The LHCb Silicon Tracker

    Energy Technology Data Exchange (ETDEWEB)

    Tobin, Mark, E-mail: Mark.Tobin@epfl.ch

    2016-09-21

    The LHCb experiment is dedicated to the study of heavy flavour physics at the Large Hadron Collider (LHC). The primary goal of the experiment is to search for indirect evidence of new physics via measurements of CP violation and rare decays of beauty and charm hadrons. The LHCb detector has a large-area silicon micro-strip detector located upstream of a dipole magnet, and three tracking stations with silicon micro-strip detectors in the innermost region downstream of the magnet. These two sub-detectors form the LHCb Silicon Tracker (ST). This paper gives an overview of the performance and operation of the ST during LHC Run 1. Measurements of the observed radiation damage are shown and compared to the expectation from simulation.

  15. LHCb experiment magnets

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    The leading members of the LHCb magnet project, from left to right: Pierre-Ange Giudici, who organized and supervised the industrial production of the coils; Marcello Losasso, who performed the 3D calculations to optimise the magnetic field; Olivier Jamet, responsible for the 3D design; Jean Renaud, in charge of the magnet assembly, and Wilfried Flegel, project leader. The LHCb detector will investigate matter-antimatter differences in B mesons at the LHC. The coils of the detector's huge dipole magnet are seen here in April 2004.

  16. LHCb VELO Upgrade

    CERN Document Server

    van Beuzekom, Martin; Ketel, Tjeerd; Gershon, Timothy; Parkes, Christopher; Reid, Matthew

    2011-01-01

    The VErtex LOcator (VELO) is a vital piece of apparatus for allowing precision measurements in hadronic physics. It provides not only superb impact parameter resolutions but also excellent momentum resolution, both important discriminating tools for precision high energy physics. This poster focuses on the R&D going into the future LHCb VELO detector. At present there are two proposed options for the upgrade; pixel chips or strip detectors. The LHCb upgrade is designed with higher luminosities and increased yields in mind. In order to get more out of the LHCb detector changes to the front end electronics will have to be made. At present, the first level hardware trigger is sets a limiting factor on the maximum efficiency for hadronic channels. As the VELO is positioned so close the proton-proton interaction region, whatever the choice of sensor, we will require efficient cooling and some proposed solutions are outlined. The LHCb TimePix telescope has had a very successful years running, with various devic...

  17. The LHCb Starterkit initiative

    CERN Document Server

    Puig Navarro, Albert

    2017-01-01

    The vast majority of high-energy physicists use and produce software every day. Software skills are usually acquired on the go and dedicated training courses are rare. The LHCb Starterkit is a new training format for getting LHCb collaborators started in effectively using software to perform their research. The initiative, combining courses and online tutorials, focuses on teaching basic skills for research computing, as well as LHCb software specifics. Unlike traditional tutorials we focus on starting with basics, performing all the material live, with a high degree of interactivity, giving priority to understanding the tools as opposed to handing out recipes that work “as if by magic”. The LHCb Starterkit was started by young members of the collaboration inspired by the principles of Software Carpentry, and the material is created in a collaborative fashion using the tools we teach. Three successful entry-level workshops, as well as two advanced ones, have taken place since the start of the initiative i...

  18. The LHCb Grid Simulation

    CERN Multimedia

    Baranov, Alexander

    2016-01-01

    The LHCb Grid access if based on the LHCbDirac system. It provides access to data and computational resources to researchers with different geographical locations. The Grid has a hierarchical topology with multiple sites distributed over the world. The sites differ from each other by their number of CPUs, amount of disk storage and connection bandwidth. These parameters are essential for the Grid work. Moreover, job scheduling and data distribution strategy have a great impact on the grid performance. However, it is hard to choose an appropriate algorithm and strategies as they need a lot of time to be tested on the real grid. In this study, we describe the LHCb Grid simulator. The simulator reproduces the LHCb Grid structure with its sites and their number of CPUs, amount of disk storage and bandwidth connection. We demonstrate how well the simulator reproduces the grid work, show its advantages and limitations. We show how well the simulator reproduces job scheduling and network anomalies, consider methods ...

  19. LHCb - measuring beauty

    CERN Multimedia

    2001-01-01

    When is a VELO not a bike? When it's something a bit more complex, like the vertex detector of the LHCb experiment. VELO stands for VErtex LOcator, and its Technical Design Report was presented, along with that for the experiment's muon detector, in July.

  20. LHCb - measuring beauty

    CERN Document Server

    2001-01-01

    When is a VELO not a bike? When it's something a bit more complex, like the vertex detector of the LHCb experiment. VELO stands for VErtex LOcator, and its Technical Design Report was presented, along with that for the experiment's muon detector, in

  1. LHCb jet reconstruction

    International Nuclear Information System (INIS)

    Francisco, Oscar; Rangel, Murilo; Barter, William; Bursche, Albert; Potterat, Cedric; Coco, Victor

    2012-01-01

    Full text: The Large Hadron Collider (LHC) is the most powerful particle accelerator in the world. It has been designed to collide proton beams at an energy up to 14 TeV in the center of mass. In 2011, the data taking was done with a center of mass energy of 7 TeV, the instant luminosity has reached values greater than 4 X 10 32 cm -2 s -1 and the integrated luminosity reached the value of 1,02fb -1 on the LHCb. The jet reconstruction is fundamental to observe events that can be used to test perturbative QCD (pQCD). It also provides a way to observe standard model channels and searches for new physics like SUSY. The anti-kt algorithm is a jet reconstruction algorithm that is based on the distance of the particles on the space ηX φ and on the transverse momentum of particles. To maximize the energy resolution all information about the trackers and the colorimeters are used on the LHCb experiment to create objects called particle flow objects that are used as input to anti-kt algorithm. The LHCb is specially interesting for jets studies because its η region is complementary to the others main experiments on LHC. We will present the first results of jet reconstruction using 2011 LHCb data. (author)

  2. LHCb jet reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Francisco, Oscar; Rangel, Murilo [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Barter, William [University of Cambridge, Cambridge (United Kingdom); Bursche, Albert [Universitat Zurich, Zurich (Switzerland); Potterat, Cedric [Universitat de Barcelona, Barcelona (Spain); Coco, Victor [Nikhef National Institute for Subatomic Physics, Amsterdam (Netherlands)

    2012-07-01

    Full text: The Large Hadron Collider (LHC) is the most powerful particle accelerator in the world. It has been designed to collide proton beams at an energy up to 14 TeV in the center of mass. In 2011, the data taking was done with a center of mass energy of 7 TeV, the instant luminosity has reached values greater than 4 X 10{sup 32} cm{sup -2}s{sup -1} and the integrated luminosity reached the value of 1,02fb{sup -1} on the LHCb. The jet reconstruction is fundamental to observe events that can be used to test perturbative QCD (pQCD). It also provides a way to observe standard model channels and searches for new physics like SUSY. The anti-kt algorithm is a jet reconstruction algorithm that is based on the distance of the particles on the space {eta}X {phi} and on the transverse momentum of particles. To maximize the energy resolution all information about the trackers and the colorimeters are used on the LHCb experiment to create objects called particle flow objects that are used as input to anti-kt algorithm. The LHCb is specially interesting for jets studies because its {eta} region is complementary to the others main experiments on LHC. We will present the first results of jet reconstruction using 2011 LHCb data. (author)

  3. B Physics at LHCb

    CERN Document Server

    Pepe Altarelli, Monica

    2008-01-01

    LHCb is a dedicated detector for b physics at the LHC. In this article we present a concise review of the detector design and performance together with the main physics goals and their relevance for a precise test of the Standard Model and search of New Physics beyond it.

  4. LHCb: Hardware Data Injector

    CERN Multimedia

    Delord, V; Neufeld, N

    2009-01-01

    The LHCb High Level Trigger and Data Acquisition system selects about 2 kHz of events out of the 1 MHz of events, which have been selected previously by the first-level hardware trigger. The selected events are consolidated into files and then sent to permanent storage for subsequent analysis on the Grid. The goal of the upgrade of the LHCb readout is to lift the limitation to 1 MHz. This means speeding up the DAQ to 40 MHz. Such a DAQ system will certainly employ 10 Gigabit or technologies and might also need new networking protocols: a customized TCP or proprietary solutions. A test module is being presented, which integrates in the existing LHCb infrastructure. It is a 10-Gigabit traffic generator, flexible enough to generate LHCb's raw data packets using dummy data or simulated data. These data are seen as real data coming from sub-detectors by the DAQ. The implementation is based on an FPGA using 10 Gigabit Ethernet interface. This module is integrated in the experiment control system. The architecture, ...

  5. The LHCb trigger

    International Nuclear Information System (INIS)

    Korolko, I.

    1998-01-01

    This paper describes progress in the development of the LHCb trigger system since the letter of intent. The trigger philosophy has significantly changed, resulting in an increase of trigger efficiency for signal B events. It is proposed to implement a level-1 vertex topology trigger in specialised hardware. (orig.)

  6. The LHCb Turbo stream

    Energy Technology Data Exchange (ETDEWEB)

    Puig, A., E-mail: albert.puig@cern.ch

    2016-07-11

    The LHCb experiment will record an unprecedented dataset of beauty and charm hadron decays during Run II of the LHC, set to take place between 2015 and 2018. A key computing challenge is to store and process this data, which limits the maximum output rate of the LHCb trigger. So far, LHCb has written out a few kHz of events containing the full raw sub-detector data, which are passed through a full offline event reconstruction before being considered for physics analysis. Charm physics in particular is limited by trigger output rate constraints. A new streaming strategy includes the possibility to perform the physics analysis with candidates reconstructed in the trigger, thus bypassing the offline reconstruction. In the Turbo stream the trigger will write out a compact summary of physics objects containing all information necessary for analyses. This will allow an increased output rate and thus higher average efficiencies and smaller selection biases. This idea will be commissioned and developed during 2015 with a selection of physics analyses. It is anticipated that the turbo stream will be adopted by an increasing number of analyses during the remainder of LHC Run II (2015–2018) and ultimately in Run III (starting in 2020) with the upgraded LHCb detector.

  7. LHCb; DAQ Architecture for the LHCb Upgrade

    CERN Multimedia

    Neufeld, N

    2013-01-01

    LHCb will have an upgrade of its detector in 2018. After the upgrade, the LHCb experiment will run at a high luminosity of 2x 10$^{33}$ cm$^{-2}$ . s$^{-1}$. The upgraded detector will be read out at 40 MHz with a highly flexible software-based triggering strategy. The Data Acquisition (DAQ) system of HCb reads out the data fragments from the Front-End Electronics and transports them to the High-Lever Trigger farm at an aggregate throughput of 32 Tbit/s. The DAQ system will be based on high speed network technologies such as InfiniBand and/or 10/40/100 Gigabit Ethernet. Independent of the network technology, there are different possible architectures for the DAQ system. In this paper, we present our studies on the DAQ architecture, where we analyze size, complexity and (relative) cost. We evaluate and compare several data-flow schemes for a network-based DAQ: push, pull and push with barrel-shifter traffic shaping. We also discuss the requirements and overall implications of the data-flow schemes on the DAQ ...

  8. LHCb: Radiation Damage in the LHCb VELO

    CERN Multimedia

    Rodriguez Perez, P

    2012-01-01

    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 88 VELO sensors are all n-on-n type but one, which is made from n-on-p silicon, and is the only n-on-p module silicon sensor operated at the LHC. The sensors have an inner radius of only 7 mm from the LHC beam and an outer radius of 42 mm, consequently the sensors receive a large and non-uniform radiation dose. The LHCb is planned to record an integrated luminosity up to 5 $fb^{-1}$ with collision energies between 7 and 14 TeV before 2018. The leakage current in the sensors has increased significantly following the delivered luminosity, and decreased during shutdown periods due to annealing. The effective depletion voltage of the sensors is measured from the charge collection effi...

  9. Study of the violation of the T and CP symmetries in the reactions {lambda}{sub b}{sup 0} {yields} {lambda}{sup 0} + a vector meson. Validation of the Front-end electronics for the PreShower detector of the LHCb experiment; Recherche de la violation des symetries CP et T dans les reactions {lambda}{sub b}{sup 0} {yields} {lambda}{sup 0} + un meson vecteur. Validation de l'architecture de lecteur des canaux du detecteur de pied de gerbe de l'experience LHCb

    Energy Technology Data Exchange (ETDEWEB)

    Conte, E

    2007-11-15

    This thesis probes the beauty baryon physics in the framework of the LHCb experiment. The present study deals with the {lambda}{sub b}{sup 0} {yields} {lambda}{sup 0}V decays where V is a vector meson such as J/{psi}({mu}{sup +}{mu}{sup -}), {phi}(K{sup +}K{sup -}), {omega}({pi}{sup +}{pi}{sup -}{pi}0) or the {rho}{sup 0} - {omega}{sup 0}({pi}{sup +}{pi}{sup -}) mixing. These processes allow to test independently the CP symmetry, which violation has not been observed yet in the baryonic sector, and the T symmetry, which experimental proofs are limited. Among the possible perspectives, a precise measurement of the {lambda}{sub b}{sup 0} lifetime could contribute to the resolution of the raising theoretical-experimental puzzle. A phenomenological model of the {lambda}{sub b}{sup 0} {yields} {lambda}{sup 0}V decays has been performed, from which branching ratios and angular distributions have been estimated. An advanced study of the reconstruction and the selection of these reactions by the LHCb apparatus shows that the channel {lambda}{sub b}{sup 0} {yields} {lambda}{sup 0}J/{psi} is the dominant channel on both statistics and purity aspects. The {lambda}{sub b}{sup 0} lifetime measure is the most imminent result; the constrains on asymmetries due to CP and T violation require several data taking years. Besides, an instrumental work has been achieved on the read-out electronics, called Front-End, of the experiment pre-shower. This contribution takes into account the validation of the prototype boards and the development of tools required by the qualification of the 100 production boards. (author)

  10. Behind the scenes at LHCb

    CERN Multimedia

    Katarina Anthony

    2010-01-01

    A new book chronicling the journey of LHCb has just been published: “LHCb: the collaboration in photos”. It takes readers through the creation of the detector, from the project's inception to the construction of the site and final operation.   Cover of the new book, "LHCb: the collaboration in photos". “LHCb: the collaboration in photos” presents a stunning collection of images and information about the experiment and its staff. Part photo journal of the experiment’s creation, part introduction to the physics and engineering of the detector, it provides a complete overview of the LHCb project. The many faces of the LHCb collaboration are reflected in the 77 glossy pages of the new book: from technical staff to computer scientists, physicists to secretaries, and Nobel Prize winners to post-docs. For all of its members, the book represents a well-earned celebration of their 15 years of effort. “We are very pleased to ha...

  11. LHCb: Upgrade of the LHCb calorimeter electronics

    CERN Multimedia

    Mauricio Ferre, J

    2013-01-01

    The LHCb collaboration foresees a major upgrade of the detector for the high luminosity run that should take place after 2018. Apart from the increase of the instantaneous luminosity at the interaction point of the experiment, one of the major ingredients of this upgrade is a full readout at 40MHz of the sub-detectors and the acquisition of the data by a large farm of PC. The trigger will be done by this farm and should increase the overall trigger efficiency with respect to the current detector, especially in hadronic B meson decays. A general overview of the modifications foreseen to the calorimeter system and the integration of the electromagnetic and hadronic calorimeters in this new scheme will be described.

  12. LHCb: Managing Large Data Productions in LHCb

    CERN Multimedia

    Tsaregorodtsev, A

    2009-01-01

    LHC experiments are producing very large volumes of data either accumulated from the detectors or generated via the Monte-Carlo modeling. The data should be processed as quickly as possible to provide users with the input for their analysis. Processing of multiple hundreds of terabytes of data necessitates generation, submission and following a huge number of grid jobs running all over the Computing Grid. Manipulation of these large and complex workloads is impossible without powerful production management tools. In LHCb, the DIRAC Production Management System (PMS) is used to accomplish this task. It enables production managers and end-users to deal with all kinds of data generation, processing and storage. Application workflow tools allow to define jobs as complex sequences of elementary application steps expressed as Directed Acyclic Graphs. Specialized databases and a number of dedicated software agents ensure automated data driven job creation and submission. The productions are accomplished by thorough ...

  13. LHCb: LHCb results on $B$ meson mixing

    CERN Multimedia

    Eitschberger, U

    2013-01-01

    On the poster three LHCb results on B meson mixing using a datasample of 1 fb$^{-1}$ of $pp$ collisions at $\\sqrt{s} =$ 7 TeV are presented. The B meson oscillation frequencies are measured as $\\Delta m_d = 0.5156 \\pm 0.0051 (\\text{stat}) \\pm 0.0033 (\\text{syst}) \\text{ps}^{-1}$ and $\\Delta m_s = 17.768 \\pm 0.023 (\\text{stat}) \\pm 0.006 (\\text{syst}) \\text{ps}^{-1}$. The CP violation observables in the decay channel $B^0 \\rightarrow J/\\psi K^0_S$ are determined as $S_{J/\\psi K^0_S} = 0.73 \\pm 0.07 (\\text{stat})\\pm 0.04 (\\text{syst})$ and $C_{J/\\psi K^0_S} = 0.03 \\pm 0.09 (\\text{stat})\\pm 0.01 (\\text{syst})$.

  14. Optimisation of the LHCb detector

    CERN Document Server

    Hierck, R H

    2003-01-01

    This thesis describes a comparison of the LHCb classic and LHCb light concept from a tracking perspective. The comparison includes the detector occupancies, the various pattern recognition algorithms and the reconstruction performance. The final optimised LHCb setup is used to study the physics performance of LHCb for the Bs->DsK and Bs->DsPi decay channels. This includes both the event selection and a study of the sensitivity for the Bs oscillation frequency, delta m_s, the Bs lifetime difference, DGamma_s, and the CP parameter gamma-2delta gamma.

  15. LHCb trigger streams optimization

    Science.gov (United States)

    Derkach, D.; Kazeev, N.; Neychev, R.; Panin, A.; Trofimov, I.; Ustyuzhanin, A.; Vesterinen, M.

    2017-10-01

    The LHCb experiment stores around 1011 collision events per year. A typical physics analysis deals with a final sample of up to 107 events. Event preselection algorithms (lines) are used for data reduction. Since the data are stored in a format that requires sequential access, the lines are grouped into several output file streams, in order to increase the efficiency of user analysis jobs that read these data. The scheme efficiency heavily depends on the stream composition. By putting similar lines together and balancing the stream sizes it is possible to reduce the overhead. We present a method for finding an optimal stream composition. The method is applied to a part of the LHCb data (Turbo stream) on the stage where it is prepared for user physics analysis. This results in an expected improvement of 15% in the speed of user analysis jobs, and will be applied on data to be recorded in 2017.

  16. The LHCb Run Control

    CERN Document Server

    Alessio, F; Callot, O; Duval, P-Y; Franek, B; Frank, M; Galli, D; Gaspar, C; v Herwijnen, E; Jacobsson, R; Jost, B; Neufeld, N; Sambade, A; Schwemmer, R; Somogyi, P

    2010-01-01

    LHCb has designed and implemented an integrated Experiment Control System. The Control System uses the same concepts and the same tools to control and monitor all parts of the experiment: the Data Acquisition System, the Timing and the Trigger Systems, the High Level Trigger Farm, the Detector Control System, the Experiment's Infrastructure and the interaction with the CERN Technical Services and the Accelerator. LHCb's Run Control, the main interface used by the experiment's operator, provides access in a hierarchical, coherent and homogeneous manner to all areas of the experiment and to all its sub-detectors. It allows for automated (or manual) configuration and control, including error recovery, of the full experiment in its different running modes. Different instances of the same Run Control interface are used by the various sub-detectors for their stand-alone activities: test runs, calibration runs, etc. The architecture and the tools used to build the control system, the guidelines and components provid...

  17. IHEP in the LHCb

    CERN Multimedia

    2001-01-01

    The LHCb hadron calorimeter (HCAL), designed at IHEP, is a sampling device made out of steel and scintillating tiles readout by wavelength-shifting fibers. A total of 52 modules have to be produced to built up the two halves of the HCAL structure. IHEP took responsibility for the tiles production, assembling and testing of the modules and for precise machining of the optics components.

  18. Layout of LHCb

    CERN Multimedia

    CERN AC

    1998-01-01

    This diagram shows the layout for the LHCb detector, which will be part of the LHC project at CERN. The main purpose of this detector is to look for rare decays of a heavy quark known as 'bottom', a version of the down quark that is found in protons and neutrons. In particular, decays by a process known as 'CP violation' will be studied to investigate Nature's preference for matter over antimatter.

  19. The LHCb electromagnetic calorimeter

    CERN Multimedia

    Maximilien Brice

    2005-01-01

    This huge 6X7 square metre wall consists of 3300 blocks containing scintillator, fibre optics and lead, which took engineers on the LHCb experiment at CERN only one month to construct. It will measure the energy of particles produced in proton-proton collisions at the LHC when it is started in 2008. Photons, electrons and positrons will pass through the layers of material in these modules and deposit their energy in the detector through a shower of particles.

  20. Electroweak penguins at LHCb

    CERN Document Server

    AUTHOR|(CDS)2073177

    2016-01-01

    Electroweak penguin decays are flavour-changing neutral current processes, and are highly suppressed in the Stan- dard Model. They can only proceed via loop diagrams. Such decays may receive contributions from New Physics and change their decay behaviours like decay rate and angular distribution. Studying the properties of these decays thus provides a powerful method to probe for New Physics. In this contribution the most recent LHCb results on electroweak penguin decays are reported.

  1. Electroweak penguins at LHCb

    Science.gov (United States)

    He, Jibo; LHCb Collaboration

    2016-04-01

    Electroweak penguin decays are flavour-changing neutral current processes, and are highly suppressed in the Standard Model. They can only proceed via loop diagrams. Such decays may receive contributions from New Physics and change their decay behaviours like decay rate and angular distribution. Studying the properties of these decays thus provides a powerful method to probe for New Physics. In this contribution the most recent LHCb results on electroweak penguin decays are reported.

  2. LHCb CP violation

    CERN Document Server

    Vesterinen, Mika

    2016-01-01

    The study of $CP$ violation in the beauty hadron sector is a promising approach to search for the effects of physics beyond the Standard Model. Several recent measurements in this area from the LHCb experiment are reported in these proceedings. These are based on the Run-I dataset of 3~fb$^{-1}$ of data collected at proton-proton centre of mass energies of 7 and 8~TeV.

  3. The LHCb Turbo stream

    CERN Document Server

    AUTHOR|(CDS)2070171

    2016-01-01

    The LHCb experiment will record an unprecedented dataset of beauty and charm hadron decays during Run II of the LHC, set to take place between 2015 and 2018. A key computing challenge is to store and process this data, which limits the maximum output rate of the LHCb trigger. So far, LHCb has written out a few kHz of events containing the full raw sub-detector data, which are passed through a full offline event reconstruction before being considered for physics analysis. Charm physics in particular is limited by trigger output rate constraints. A new streaming strategy includes the possibility to perform the physics analysis with candidates reconstructed in the trigger, thus bypassing the offline reconstruction. In the Turbo stream the trigger will write out a compact summary of physics objects containing all information necessary for analyses. This will allow an increased output rate and thus higher average efficiencies and smaller selection biases. This idea will be commissioned and developed during 2015 wi...

  4. LHCb distributed conditions database

    International Nuclear Information System (INIS)

    Clemencic, M

    2008-01-01

    The LHCb Conditions Database project provides the necessary tools to handle non-event time-varying data. The main users of conditions are reconstruction and analysis processes, which are running on the Grid. To allow efficient access to the data, we need to use a synchronized replica of the content of the database located at the same site as the event data file, i.e. the LHCb Tier1. The replica to be accessed is selected from information stored on LFC (LCG File Catalog) and managed with the interface provided by the LCG developed library CORAL. The plan to limit the submission of jobs to those sites where the required conditions are available will also be presented. LHCb applications are using the Conditions Database framework on a production basis since March 2007. We have been able to collect statistics on the performance and effectiveness of both the LCG library COOL (the library providing conditions handling functionalities) and the distribution framework itself. Stress tests on the CNAF hosted replica of the Conditions Database have been performed and the results will be summarized here

  5. The LHCb Starterkit

    Science.gov (United States)

    Puig, Albert; LHCb Starterkit Team

    2017-10-01

    The vast majority of high-energy physicists use and produce software every day. Software skills are usually acquired “on the go” and dedicated training courses are rare. The LHCb Starterkit is a new training format for getting LHCb collaborators started in effectively using software to perform their research. The course focuses on teaching basic skills for research computing. Unlike traditional tutorials we focus on starting with basics, performing all the material live, with a high degree of interactivity, giving priority to understanding the tools as opposed to handing out recipes that work “as if by magic”. The LHCb Starterkit was started by two young members of the collaboration inspired by the principles of Software Carpentry, and the material is created in a collaborative fashion using the tools we teach. Three successful entry-level workshops, as well as an advance one, have taken place since the start of the initiative in 2015, and were taught largely by PhD students to other PhD students.

  6. The LHCb DAQ system

    CERN Document Server

    Jost, B

    2000-01-01

    The LHCb experiment is the most recently approved of the 4 experiments under construction at CERN's LHC accelerator. It is a special purpose experiment designed to precisely measure the CP violation parameters in the B-B system. Triggering poses special problems since the interesting events containing B-mesons are immersed in a large background of inelastic p-p reactions. We therefore decided to implement a 4 level triggering scheme. The LHCb Data Acquisition (DAQ) system will have to cope with an average trigger rate of similar to 40 kHz, after two levels of hardware triggers, and an average event size of similar to 150 kB. Thus an event-building network which can sustain an average bandwidth of 6 GB /s is required. A powerful software trigger farm will have to be installed to reduce the rate from the 40 kHz to similar to 200 Hz of events written to permanent storage. In this paper we will concentrate on the networking aspects of the LHCb data acquisition and the controls system. 11 Refs.

  7. LHCb; Neutral Higgs $ \\to \\tau \\tau$ Limits at LHCb

    CERN Multimedia

    Ilten, P

    2013-01-01

    LHCb is fully instrumented in the forward region, $2 \\leq \\eta \\leq 5$, and provides compelentary results to the central measurements of ATLAS and CMS. Preliminary limits are presented on neutral Higgs production usint $\\tau \\tau$ final states in the forward region of LHCb.

  8. LHCB Searches for long-lived heavy particles at LHCb

    CERN Multimedia

    Marin Benito, Carla

    2014-01-01

    Its forward acceptance and good resolution allow LHCb to perform competitive searches for heavy particles beyond the Standard Model. We report a search for the stau particle with the LHCb detector and give our prospects for searches of Hidden Valley particles.

  9. LHCb: Recent results on B and D decays from LHCb

    CERN Multimedia

    Obłakowska-Mucha, A

    2014-01-01

    The LHCb experiment has collected more than 3 fb$^{-1}$ of integrated luminosity in 2011 and 2012 and is producing a large amount of excellent results in beauty and charmed meson physics. An overview of the most recent results on rare B decays, CP violation, and charm physics will be given along with an outlook to the physics perspectives and to the LHCb upgrade.

  10. LHCb : Tracking system of the LHCb upgrade

    CERN Multimedia

    Szumlak, Tomasz

    2015-01-01

    The upgrade of the LHCb experiment will run at an instantaneous luminosity of 2x10^33 cm^-2 s^-1 with a fully software based trigger, allowing to read out the detector at a rate of 40MHz. For this purpose, the full tracking system will be newly developed: the vertex locator (VELO) will be replaced by a pixel-based detector, withstanding the high radiation dose and providing an excellent track reconstruction with an efficiency of above 99% for all charged particles of interest. Upstream of the magnet, a silicon mico-strip detector with a high granularity and an improved acceptance coverage, called the Upstream Tracker (UT), will replace the current silicon strip tracker, and provide a rough momentum estimate. The tracking system downstream of the magnet will be replaced by the Scintillating Fibre tracker (SciFi), which will consist of 12 layers using 2.5m long scintillating fibres read out by silicon photo-multipliers, providing a spatial resolution better than 100 micron and resulting in a total momentum reso...

  11. The LHCb Silicon Tracker

    CERN Document Server

    Elsasser, Ch; Gallas Torreira, A; Pérez Trigo, A; Rodríguez Pérez, P; Bay, A; Blanc, F; Dupertuis, F; Haefeli, G; Komarov, I; Märki, R; Muster, B; Nakada, T; Schneider, O; Tobin, M; Tran, M T; Anderson, J; Bursche, A; Chiapolini, N; Saornil, S; Steiner, S; Steinkamp, O; Straumann, U; Vollhardt, A; Britsch, M; Schmelling, M; Voss, H; Okhrimenko, O; Pugatch, V

    2013-01-01

    The aim of the LHCb experiment is to study rare heavy quark decays and CP vio- lation with the high rate of beauty and charmed hadrons produced in $pp$ collisions at the LHC. The detector is designed as a single-arm forward spectrometer with excellent tracking and particle identification performance. The Silicon Tracker is a key part of the tracking system to measure the particle trajectories to high precision. This paper reports the performance as well as the results of the radiation damage monitoring based on leakage currents and on charge collection efficiency scans during the data taking in the LHC Run I.

  12. LHCb Dockerized Build Environment

    Science.gov (United States)

    Clemencic, M.; Belin, M.; Closier, J.; Couturier, B.

    2017-10-01

    Used as lightweight virtual machines or as enhanced chroot environments, Linux containers, and in particular the Docker abstraction over them, are more and more popular in the virtualization communities. The LHCb Core Software team decided to investigate how to use Docker containers to provide stable and reliable build environments for the different supported platforms, including the obsolete ones which cannot be installed on modern hardware, to be used in integration builds, releases and by any developer. We present here the techniques and procedures set up to define and maintain the Docker images and how these images can be used to develop on modern Linux distributions for platforms otherwise not accessible.

  13. Flavour Tagging at LHCb

    CERN Multimedia

    Grabalosa Gandara, M

    2009-01-01

    To do precise CP violation measurements, the most possible accurate knowledge of the flavour at production of the reconstructed B meson is required. This poster summarizes the flavour tagging performances for the LHCb experiment. We use same side an opposite side algorithms to establish wheter the meson contained a b or a b\\bar quark. The final decision is obtained through a combination of several methods. The use of control channels, decays to a flavour specific final state, will allow to determine the wrong tag fraction \\omega (the probability of a tag to be wrong), which can be used as input for the determination of CKM unitary triangle angles.

  14. Recherche directe à LHCb du boson de Higgs en production associée et contribution au développement du nouveau trajectographe à fibres scintillantes

    CERN Document Server

    Jaton, Pierre

    The framework of this thesis is the Large Hadron collider, more precisely the LHCb experiment. The technical part of this work focusses on the upgrade project of the LHCb experiment, which is planned to be achieved in 2018. The LPHE is responsible for the development of the new Tracker, based on a scintillating fibers technology. A computer simulation of the fiber lattice is presented in order to estimate the efficiency and the resolution of this new detector device. These values are strongly dependent on the transverse $\\theta$ angle of the incident particles. For small values of $\\theta$ (from 0 to 15$^\\circ$), the resolution is found to be around 50 $\\mu m$ and the efficiency is close to 100 %. For $\\theta$ in the range 15 to 25$^\\circ$, the resolution is degrading to about 79 $\\mu m$ but the efficiency remains stable around 100 %. When the angle reaches values from 25 to 35$^\\circ$, the resolution falls down to 335 $\\mu m$ and the efficiency is merely 50 %. These results have to be compared to the experi...

  15. LHCb Event display

    CERN Document Server

    Trisovic, Ana

    2014-01-01

    The LHCb Event Display was made for educational purposes at the European Organization for Nuclear Research, CERN in Geneva, Switzerland. The project was implemented as a stand-alone application using C++ and ROOT, a framework developed by CERN for data analysis. This paper outlines the development and architecture of the application in detail, as well as the motivation for the development and the goals of the exercise. The application focuses on the visualization of events recorded by the LHCb detector, where an event represents a set of charged particle tracks in one proton-proton collision. Every particle track is coloured by its type and can be selected to see its essential information such as mass and momentum. The application allows students to save this information and calculate the invariant mass for any pair of particles. Furthermore, the students can use additional calculating tools in the application and build up a histogram of these invariant masses. The goal for the students is to find a $D^0$ par...

  16. LHCb Topological Trigger Reoptimization

    CERN Document Server

    INSPIRE-00400931; Ilten, Philip; Khairullin, Egor; Rogozhnikov, Alex; Ustyuzhanin, Andrey; Williams, Michael

    2015-12-23

    The main b-physics trigger algorithm used by the LHCb experiment is the so-called topological trigger. The topological trigger selects vertices which are a) detached from the primary proton-proton collision and b) compatible with coming from the decay of a b-hadron. In the LHC Run 1, this trigger, which utilized a custom boosted decision tree algorithm, selected a nearly 100% pure sample of b-hadrons with a typical efficiency of 60-70%; its output was used in about 60% of LHCb papers. This talk presents studies carried out to optimize the topological trigger for LHC Run 2. In particular, we have carried out a detailed comparison of various machine learning classifier algorithms, e.g., AdaBoost, MatrixNet and neural networks. The topological trigger algorithm is designed to select all "interesting" decays of b-hadrons, but cannot be trained on every such decay. Studies have therefore been performed to determine how to optimize the performance of the classification algorithm on decays not used in the training. ...

  17. LHCb Topological Trigger Reoptimization

    International Nuclear Information System (INIS)

    Likhomanenko, Tatiana; Khairullin, Egor; Rogozhnikov, Alex; Ustyuzhanin, Andrey; Ilten, Philip; Williams, Michael

    2015-01-01

    The main b-physics trigger algorithm used by the LHCb experiment is the so- called topological trigger. The topological trigger selects vertices which are a) detached from the primary proton-proton collision and b) compatible with coming from the decay of a b-hadron. In the LHC Run 1, this trigger, which utilized a custom boosted decision tree algorithm, selected a nearly 100% pure sample of b-hadrons with a typical efficiency of 60-70%; its output was used in about 60% of LHCb papers. This talk presents studies carried out to optimize the topological trigger for LHC Run 2. In particular, we have carried out a detailed comparison of various machine learning classifier algorithms, e.g., AdaBoost, MatrixNet and neural networks. The topological trigger algorithm is designed to select all ’interesting” decays of b-hadrons, but cannot be trained on every such decay. Studies have therefore been performed to determine how to optimize the performance of the classification algorithm on decays not used in the training. Methods studied include cascading, ensembling and blending techniques. Furthermore, novel boosting techniques have been implemented that will help reduce systematic uncertainties in Run 2 measurements. We demonstrate that the reoptimized topological trigger is expected to significantly improve on the Run 1 performance for a wide range of b-hadron decays. (paper)

  18. The LHCb VELO upgrade

    International Nuclear Information System (INIS)

    Rodríguez Pérez, Pablo

    2013-01-01

    LHCb is a forward spectrometer experiment dedicated to the study of new physics in the decays of beauty and charm hadrons produced in proton collisions at the Large Hadron Collider (LHC) at CERN. The VErtex LOcator (VELO) is the microstrip silicon detector surrounding the interaction point, providing tracking and vertexing measurements. The upgrade of the LHCb experiment, planned for 2018, will increase the luminosity up to 2×10 33 cm −2 s −1 and will perform the readout as a trigger-less system with an event rate of 40 MHz. Extremely non-uniform radiation doses will reach up to 5×10 15 1 MeV n eq /cm 2 in the innermost regions of the VELO sensors, and the output data bandwidth will be increased by a factor of 40. An upgraded detector is under development based in a pixel sensor of the Timepix/Medipix family, with 55×55μm 2 pixels. In addition a microstrip solution with finer pitch, higher granularity and thinner than the current detector is being developed in parallel. The current status of the VELO upgrade program will be described together with recent testbeam results

  19. The LHCb Run Control

    Energy Technology Data Exchange (ETDEWEB)

    Alessio, F; Barandela, M C; Frank, M; Gaspar, C; Herwijnen, E v; Jacobsson, R; Jost, B; Neufeld, N; Sambade, A; Schwemmer, R; Somogyi, P [CERN, 1211 Geneva 23 (Switzerland); Callot, O [LAL, IN2P3/CNRS and Universite Paris 11, Orsay (France); Duval, P-Y [Centre de Physique des Particules de Marseille, Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Franek, B [Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX (United Kingdom); Galli, D, E-mail: Clara.Gaspar@cern.c [Universita di Bologna and INFN, Bologna (Italy)

    2010-04-01

    LHCb has designed and implemented an integrated Experiment Control System. The Control System uses the same concepts and the same tools to control and monitor all parts of the experiment: the Data Acquisition System, the Timing and the Trigger Systems, the High Level Trigger Farm, the Detector Control System, the Experiment's Infrastructure and the interaction with the CERN Technical Services and the Accelerator. LHCb's Run Control, the main interface used by the experiment's operator, provides access in a hierarchical, coherent and homogeneous manner to all areas of the experiment and to all its sub-detectors. It allows for automated (or manual) configuration and control, including error recovery, of the full experiment in its different running modes. Different instances of the same Run Control interface are used by the various sub-detectors for their stand-alone activities: test runs, calibration runs, etc. The architecture and the tools used to build the control system, the guidelines and components provided to the developers, as well as the first experience with the usage of the Run Control will be presented

  20. LHCb computing tasks

    CERN Document Server

    Binko, P

    1998-01-01

    This document describes the computing tasks of the LHCb computing system. It also describes the logistics of the dataflow between the tasks and the detailed requirements for each task, in particular the data sizes and CPU power requirements. All data sizes are calculated assuming that the LHCb experiment will take data about 107 s per year at a frequency of 200 Hz, which gives 2 \\Theta 109 real events per year. The raw event size should not exceed 100 kB (200 TB per year). We will have to generate about 109 MonteCarlo events per year. The current MonteCarlo simulation program based on the GEANT3.21 package requires about 12 s to produce an average event (all CPU times are normalised to a 1000 MIPS processor). The size of an average MonteCarlo event will be about 200 kB (100 TB per year) of simulated data (without the hits). We will start to use the GEANT4 package in 1998. Rejection factors of 8 and 25 are required in the Level-2 and Level-3 triggers respectively, to reduce the frequency of events to 200 Hz. T...

  1. LHCb experience with LFC replication

    International Nuclear Information System (INIS)

    Bonifazi, F; Carbone, A; D'Apice, A; Dell'Agnello, L; Re, G L; Martelli, B; Ricci, P P; Sapunenko, V; Vitlacil, D; Perez, E D; Duellmann, D; Girone, M; Peco, G; Vagnoni, V

    2008-01-01

    Database replication is a key topic in the framework of the LHC Computing Grid to allow processing of data in a distributed environment. In particular, the LHCb computing model relies on the LHC File Catalog, i.e. a database which stores information about files spread across the GRID, their logical names and the physical locations of all the replicas. The LHCb computing model requires the LFC to be replicated at Tier-1s. The LCG 3D project deals with the database replication issue and provides a replication service based on Oracle Streams technology. This paper describes the deployment of the LHC File Catalog replication to the INFN National Center for Telematics and Informatics (CNAF) and to other LHCb Tier-1 sites. We performed stress tests designed to evaluate any delay in the propagation of the streams and the scalability of the system. The tests show the robustness of the replica implementation with performance going much beyond the LHCb requirements

  2. The LHCb Data Management System

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    We shall describe all the tools that are available for Data Management, from handling of large datasets to basic tools for users as well as for monitoring the dynamic behaviour of LHCb Storage capacity.

  3. Heavy flavour production at LHCb

    CERN Document Server

    Barsuk, Sergey

    2016-01-01

    The present write-up reports recent LHCb results on production of quarkonium and open flavour states, as well as selected results on associated production, central exclusive production and pro- duction in heavy ion collisions.

  4. LHCb experience with LFC replication

    CERN Document Server

    Bonifazi, F; Perez, E D; D'Apice, A; dell'Agnello, L; Düllmann, D; Girone, M; Re, G L; Martelli, B; Peco, G; Ricci, P P; Sapunenko, V; Vagnoni, V; Vitlacil, D

    2008-01-01

    Database replication is a key topic in the framework of the LHC Computing Grid to allow processing of data in a distributed environment. In particular, the LHCb computing model relies on the LHC File Catalog, i.e. a database which stores information about files spread across the GRID, their logical names and the physical locations of all the replicas. The LHCb computing model requires the LFC to be replicated at Tier-1s. The LCG 3D project deals with the database replication issue and provides a replication service based on Oracle Streams technology. This paper describes the deployment of the LHC File Catalog replication to the INFN National Center for Telematics and Informatics (CNAF) and to other LHCb Tier-1 sites. We performed stress tests designed to evaluate any delay in the propagation of the streams and the scalability of the system. The tests show the robustness of the replica implementation with performance going much beyond the LHCb requirements.

  5. Central Exclusive Production at LHCb

    CERN Document Server

    INSPIRE-00106463

    2015-01-01

    Central Exclusive Production is a unique QCD process in which particles are produced via colourless propagators. Several results have been obtained at LHCb for the production of single charmonia, pairs of charmonia, and single bottomonia.

  6. Electroweak boson production at LHCb

    CERN Document Server

    Sestini, Lorenzo

    2018-01-01

    The LHCb experiment offers a complementary phase space to ATLAS and CMS to study electroweak processes, thanks to the forward acceptance and the large bandwidth of the trigger allowing low energy thresholds. For this reason electroweak measurements at LHCb can provide unique constraints to the Parton Distribution Functions. Moreover these measurements can be used to validate reconstruction techniques. In these proceedings the latest measurements on W and Z bosons production performed during the LHC Run I and Run II data taking are presented.

  7. Charm mixing at LHCb

    CERN Document Server

    Di Canto, Angelo

    2013-01-01

    We report a measurement of the time-dependent ratio of $D^0\\to K^+\\pi^-$ to $D^0\\to K^-\\pi^+$ decay rates in $D^{*+}$-tagged events using 1.0\\,fb$^{-1}$ of integrated luminosity recorded by the LHCb experiment. We measure the mixing parameters $x'^2=(-0.9\\pm1.3)\\times10^{-4}$, $y'=(7.2\\pm2.4)\\times10^{-3}$ and the ratio of doubly-Cabibbo-suppressed to Cabibbo-favored decay rates $R_D=(3.52\\pm0.15)\\times10^{-3}$. The result excludes the no-mixing hypothesis with a probability corresponding to 9.1 standard deviations and represents the first observation of charm mixing from a single measurement

  8. LHCb upstream tracker

    CERN Multimedia

    Artuso, Marina

    2016-01-01

    The detector for the LHCb upgrade is designed for 40MHz readout, allowing the experiment to run at an instantaneous luminosity of 2x10^33 cm$^2$s$^-1$. The upgrade of the tracker subsystem in front of the dipole magnet, the Upstream Tracker, is crucial for charged track reconstruction and fast trigger decisions based on a tracking algorithm involving also vertex detector information. The detector consists of 4 planes with a total area of about 8.5m$^2$, made of single sided silicon strip sensors read-out by a novel custom-made ASIC (SALT). Details on the performance of prototype sensors, front-end electronics, near-detector electronics and mechanical components are presented.

  9. The LHCb configuration database

    CERN Document Server

    Abadie, Lana; Gaspar, Clara; Jacobsson, Richard; Jost, Beat; Neufeld, Niko

    2005-01-01

    The Experiment Control System (ECS) will handle the monitoring, configuration and operation of all the LHCb experimental equipment. All parameters required to configure electronics equipment under the control of the ECS will reside in a configuration database. The database will contain two kinds of information: 1.\tConfiguration properties about devices such as hardware addresses, geographical location, and operational parameters associated with particular running modes (dynamic properties). 2.\tConnectivity between devices : this consists of describing the output and input connections of a device (static properties). The representation of these data using tables must be complete so that it can provide all the required information to the ECS and must cater for all the subsystems. The design should also guarantee a fast response time, even if a query results in a large volume of data being loaded from the database into the ECS. To fulfil these constraints, we apply the following methodology: Determine from the d...

  10. LHCb Tag Collector

    International Nuclear Information System (INIS)

    Fernández, Paloma Fuente; Clemencic, Marco; Cousin, Nicolas

    2011-01-01

    The LHCb physics software consists of hundreds of packages, each of which is developed by one or more physicists. When the developers have some code changes that they would like released, they commit them to the version control system, and enter the revision number into a database. These changes have to be integrated into a new release of each of the physics analysis applications. Tests are then performed by a nightly build system, which rebuilds various configurations of the whole software stack and executes a suite of run-time functionality tests. A Tag Collector system has been developed using solid standard technologies to cover both the use cases of developers and integration managers. A simple Web interface, based on an AJAX-like technology, is available. Integration with SVN and Nightly Build System, is possible via a Python API. Data are stored in a relational database with the help of an ORM (Object-Relational Mapping) library.

  11. The LHCb Muon Upgrade

    CERN Multimedia

    Cardini, A

    2013-01-01

    The LHCb collaboration is currently working on the upgrade of the experiment to allow, after 2018, an efficient data collection while running at an instantaneous luminosity of 2x10$^{33}$/cm$^{-2}$s$^{-1}$. The upgrade will allow 40 MHz detector readout, and events will be selected by means of a very flexible software-based trigger. The muon system will be upgraded in two phases. In the first phase, the off-detector readout electronics will be redesigned to allow complete event readout at 40 MHz. Also, part of the channel logical-ORs, used to reduce the total readout channel count, will be removed to reduce dead-time in critical regions. In a second phase, higher-granularity detectors will replace the ones installed in highly irradiated regions, to guarantee efficient muon system performances in the upgrade data taking conditions.

  12. Hadron spectroscopy in LHCb

    CERN Document Server

    Palano, Antimo

    2018-01-01

    The LHCb experiment is designed to study the properties and decays of heavy flavored hadrons produced in pp collisions at the LHC. The data collected in the LHC Run I enables precision spectroscopy studies of beauty and charm hadrons. The latest results on spectroscopy of conventional and exotic hadrons are reviewed. In particular the discovery of the first charmonium pentaquark states in the $J/\\psi p$ system, the possible existence of four-quark states decaying to $J/\\psi \\phi$ and the confirmation of resonant nature of the $Z_c(4430)^−$ mesonic state are discussed. In the sector of charmed baryons, the observation of five new $\\Omega_c$ states, the observation of the $\\Xi^+_{cc}$ and the study of charmed baryons decaying to $D^0 p$ are presented.

  13. The LHCb configuration database

    CERN Document Server

    Abadie, L; Van Herwijnen, Eric; Jacobsson, R; Jost, B; Neufeld, N

    2005-01-01

    The aim of the LHCb configuration database is to store information about all the controllable devices of the detector. The experiment's control system (that uses PVSS ) will configure, start up and monitor the detector from the information in the configuration database. The database will contain devices with their properties, connectivity and hierarchy. The ability to store and rapidly retrieve huge amounts of data, and the navigability between devices are important requirements. We have collected use cases to ensure the completeness of the design. Using the entity relationship modelling technique we describe the use cases as classes with attributes and links. We designed the schema for the tables using relational diagrams. This methodology has been applied to the TFC (switches) and DAQ system. Other parts of the detector will follow later. The database has been implemented using Oracle to benefit from central CERN database support. The project also foresees the creation of tools to populate, maintain, and co...

  14. LHCb software strategy

    CERN Document Server

    Van Herwijnen, Eric

    1998-01-01

    This document describes the software strategy of the LHCb experiment. The main objective is to reuse designs and code wherever possible; We will implement an architecturally driven design process; This architectural process will be implemented using Object Technology; We aim for platform indepence; try to take advantage of distributed computing and will use industry standards, commercial software and profit from HEP developments; We will implement a common software process and development environment. One of the major problems that we are immediately faced with is the conversion of our current code from Fortran into an Object Oriented language and the conversion of our current developers to Object technology. Some technical terms related to OO programming are defined in Annex A.1

  15. Recent LHCb Spectroscopy results

    CERN Document Server

    AUTHOR|(CDS)2075147

    2015-01-01

    Studies of B and Bs decays having a J∕ψ in the final state have been performed which allow new measurements on the scalar and axial mesons mixing angles. Two new natural parity and two unnatural parity resonances are observed in the inclusive study of D+π−, D0π+ and D∗+π− final states. In a Dalitz plot analysis of Bs0 → D0K−π+, an excess at m( D0K−) ≈ 2.86 GeV/c is found to be an admixture of spin-1 and spin-3 resonances. The analyses make use of data corresponding to 3 fb−1 of integrated luminosity collected with the LHCb detector using pp collisions.

  16. Flavour physics at LHCb

    Directory of Open Access Journals (Sweden)

    Adeva B.

    2016-01-01

    Full Text Available Some selected results of the LHCb experiment, running at the LHC with ppcollisions at 7 TeV and 8 TeV, are reported here, after operation with a total integratedluminosity of 3.0 fb−1 (Run 1. We focus on the most recent analyses on flavour physics,that include measurements of the CKM invariant phases γ and β, precision determination of the quark coupling strength Vub, observation of the very rare decays B0(s→μ+μ−, search for new physics in the anomalous branching ratio of B→D*τv̄, and precision angular analysis of the rare decays B0→K*0μ+μ− and B0s→ϕμ+μ−. Detailed comparisons are performed in all cases with the predictions of the Standard Model, and a fewinteresting tensions are observed.

  17. Rare Decays at LHCb

    CERN Document Server

    Belyaev, Ivan

    2006-01-01

    Rare loop-induced decays are sensitive to New Physics in many Standard Model extensions. In this paper we discuss the reconstruction of the radiative penguin decays $B^0_d \\to K^{*0} \\gamma, B^0_s \\to \\phi \\gamma , B^0_d \\to \\omega \\gamma, \\Lambda_b \\to \\Lambda \\gamma$, the electroweak penguin decays $B^0_d \\to K^{*0} \\mu^+ \\mu^-, B^+_u \\to K^+ \\mu^+ \\mu^-$, the gluonic penguin decays $B^0_d \\to \\phi K^0_S, B^0_s \\to \\phi \\phi$, and the decay $B^0_s \\to \\mu^+\\mu^-$ at LHCb. The selection criteria, evaluated efficiencies, expected annual yields and $B/S$ estimates are presented.

  18. LHCb Online Networking Requirements

    CERN Document Server

    Jost, B

    2003-01-01

    This document describes the networking requirements of the LHCb online installation. It lists both quantitative aspects such as the number of required switch ports, as well as some qualitative features of the equipment, such as minimum buffer sizes in switches. The document comprises both the data acquisition network and the controls/general-purpose network. While the numbers represent our best current knowledge and are intended to give (in particular) network equipment manufacturers an overview of our needs, this document should not be confused with a market survey questionnaire or a formal tendering document. However the information contained in this document will be the input of any such document. A preliminary schedule for procurement and installation is also given.

  19. Pancake day comes early for LHCb

    CERN Multimedia

    2003-01-01

    The assembly of LHCb has begun! The two coils of the LHCb magnet arrived and were lowered into the underground experimental area during the arctic conditions of Epiphany week. Deliveries for the yoke continue.

  20. LHCb Computing Resource usage in 2017

    CERN Document Server

    Bozzi, Concezio

    2018-01-01

    This document reports the usage of computing resources by the LHCb collaboration during the period January 1st – December 31st 2017. The data in the following sections have been compiled from the EGI Accounting portal: https://accounting.egi.eu. For LHCb specific information, the data is taken from the DIRAC Accounting at the LHCb DIRAC Web portal: http://lhcb-portal-dirac.cern.ch.

  1. LHCb: Installation and operation of the LHCb Silicon Tracker detector

    CERN Multimedia

    Esperante Pereira, D

    2009-01-01

    The LHCb experiment has been designed to perform high-precision measurements of CP violation and rare decays of B hadrons. The construction and installation phases of the Silicon Tracker (ST) of the experiment were completed by early summer 2008. The LHCb Silicon Tracker sums up to a total sensitive area of about 12 m^2 using silicon micro-strip technology and withstands charged particle fluxes of up to 5 x 10^5cm^−2s^−1. We will report on the preparation of the detectors for the first LHC beams. Selected results from the commissioning in LHCb are shown, including the first beam-related events accumulated during LHC injection tests in September 2008. Lessons are drawn from the experience gathered during the installation and commissioning.

  2. LHCb: Parameterization of the LHCb magnetic field map

    CERN Multimedia

    Conti, G

    2007-01-01

    The LHCb warm magnet has been designed to provide an integrated field of 4 Tm for tracks coming from the primary vertex. To insure good momentum resolution of a few per mil, an accurate description of the magnetic field map is needed. This is achieved by combining the information from a TOSCA-based simulation and data from measurements. The paper presents the fit method applied to both the simulation and data to achieve the requirements. It also explains how the corresponding software tool is integrated in the LHCb Gaudi software and shows the relation with the environment in which it is used.

  3. CERN Open Days 2013, Point 8 - LHCb: LHCb Experiment

    CERN Multimedia

    CERN Photolab

    2013-01-01

    Stand description: Fourteen billion years ago, the Universe began with a "Big Bang" in which energy coalesced to form equal quantities of matter and antimatter.  LHCb is an experiment set up to explore what happened after the Big Bang that allowed matter to survive and build the Universe we inhabit today.  During the visit the LHCb detector located 100 metres below ground will be shown together with the nearby section of the LHC. On surface no restricted access  An LHC dipole magnet and a module used to accelerate protons will be show at the surface.

  4. LHCb: A New Nightly Build System for LHCb

    CERN Multimedia

    Clemencic, M

    2013-01-01

    The nightly build system used so far by LHCb has been implemented as an extension on the system developed by CERN PH/SFT group (as presented at CHEP2010). Although this version has been working for many years, it has several limitations in terms of extensibility, management and ease of use, so that it was decided to develop a new version based on a continuous integration system. In this paper we describe a new implementation of the LHCb Nightly Build System based on the open source continuous integration system Jenkins and report on the experience on the configuration of a complex build workflow in Jenkins.

  5. LHCb: A new Readout Control system for the LHCb Upgrade

    CERN Multimedia

    Alessio, F

    2012-01-01

    The LHCb experiment has proposed an upgrade towards a full 40 MHz readout system in order to run between five and ten times its initial design luminosity. The entire readout architecture will be upgraded in order to cope with higher sub-detector occupancies, higher rate and higher network load. In this paper, we describe the architecture, functionalities and the first hardware implementation of a new Readout Control system for the LHCb upgrade. The system is based on FPGAs and bi-directional links for the control of the entire readout architecture. First results on the validation of the system are also given.

  6. LHCb connects its pipes

    CERN Multimedia

    2006-01-01

    Two weeks ago the first beryllium section of the LHCb beam vacuum chamber was installed. This three-day operation, after requiring lengthy preparation work, demanded patience and precision as the first of four sections of the beampipe was connected to the vertex locator (VeLo) vacuum vessel. The AT-VAC Group with the collaboration of PH/LBD, including Gloria Corti, Tatsuya Nakada, Patrice Mermet, Delios Ramos, Frans Mul, Bruno Versollato, Bernard Corajod, and Raymond Veness. (Not pictured: Adriana Rossi and Laurent Bouvet) This first installed section is composed of a nearly two-metre long conical tube of one-millimetre thick beryllium and of a thin spherical-shaped window, 800 millimeter diameter, made of an aluminum alloy, and has the appearance of a mushroom lying on its side. The window is connected to the conical part of the beampipe through an aluminum alloy bellow, which is needed to allow for mechanical alignment once the assembly is installed. Beryllium was chosen as the material for 12 m of the 19...

  7. The LHCb VELO upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Dosil Suárez, Álvaro, E-mail: alvaro.dosil@usc.es

    2016-07-11

    The upgrade of the LHCb experiment, planned for 2019, will transform the experiment to a trigger-less system reading out the full detector at 40 MHz event rate. All data reduction algorithms will be executed in a high-level software farm. The upgraded detector will run at luminosities of 2×10{sup 33} cm{sup −2} s{sup −1} and probe physics beyond the Standard Model in the heavy flavour sector with unprecedented precision. The Vertex Locator (VELO) is the silicon vertex detector surrounding the interaction region. The current detector will be replaced with a hybrid pixel system equipped with electronics capable of reading out at 40 MHz. The detector comprises silicon pixel sensors with 55×55 μm{sup 2} pitch, read out by the VeloPix ASIC, based on the TimePix/MediPix family. The hottest region will have pixel hit rates of 900 Mhits/s yielding a total data rate more than 3 Tbit/s for the upgraded VELO. The detector modules are located in a separate vacuum, separated from the beam vacuum by a thin custom made foil. The detector halves are retracted when the beams are injected and closed at stable beams, positioning the first sensitive pixel at 5.1 mm from the beams. The material budget will be minimised by the use of evaporative CO{sub 2} coolant circulating in microchannels within 400 μm thick silicon substrates.

  8. LHCb computing model

    CERN Document Server

    Frank, M; Pacheco, Andreu

    1998-01-01

    This document is a first attempt to describe the LHCb computing model. The CPU power needed to process data for the event filter and reconstruction is estimated to be 2.2 \\Theta 106 MIPS. This will be installed at the experiment and will be reused during non data-taking periods for reprocessing. The maximal I/O of these activities is estimated to be around 40 MB/s.We have studied three basic models concerning the placement of the CPU resources for the other computing activities, Monte Carlo-simulation (1:4 \\Theta 106 MIPS) and physics analysis (0:5 \\Theta 106 MIPS): CPU resources may either be located at the physicist's homelab, national computer centres (Regional Centres) or at CERN.The CPU resources foreseen for analysis are sufficient to allow 100 concurrent analyses. It is assumed that physicists will work in physics groups that produce analysis data at an average rate of 4.2 MB/s or 11 TB per month. However, producing these group analysis data requires reading capabilities of 660 MB/s. It is further assu...

  9. The LHCb VELO Upgrade

    CERN Document Server

    de Capua, Stefano

    2016-01-01

    The upgrade of the LHCb experiment, scheduled for LHC Run-3, will transform the experiment to a triggerless system reading out the full detector at 40 MHz event rate. All data reduction algorithms will be executed in a high-level software farm, enabling the detector to run at luminosities of 2×1033 cm−2 s −1 . The Vertex Locator (VELO) is the silicon vertex detector surrounding the interaction region. The current strip detector will be replaced with a hybrid pixel system equipped with electronics capable of reading out at 40 MHz. The upgraded VELO will allow for fast pattern recognition and track reconstruction in the software trigger. The silicon pixel sensors have 55×55 µm2 pitch, and are read out by the VeloPix ASIC. The VeloPix builds on the currently available Timepix3, modified to deliver a radiation hard design capable of an order of magnitude increase in output rate. The hottest regions will have pixel hit rates of 900 Mhits/s, yielding a total data rate more than 3 Tbit/s for the upgraded VELO...

  10. LHCb VELO Upgrade

    CERN Document Server

    Hennessy, Karol

    2016-01-01

    The upgrade of the LHCb experiment, scheduled for LHC Run-III, scheduled to start in 2021, will transform the experiment to a trigger-less system reading out the full detector at 40 MHz event rate. All data reduction algorithms will be executed in a high-level software farm enabling the detector to run at luminosities of $2\\times10^{33} \\mathrm{cm}^{-2}\\mathrm{s}^{-1}$. The Vertex Locator (VELO) is the silicon vertex detector surrounding the interaction region. The current detector will be replaced with a hybrid pixel system equipped with electronics capable of reading out at 40 MHz. The upgraded VELO will provide fast pattern recognition and track reconstruction to the software trigger. The silicon pixel sensors have $55\\times55 \\mu m^{2}$ pitch, and are read out by the VeloPix ASIC, from the Timepix/Medipix family. The hottest region will have pixel hit rates of 900 Mhits/s yielding a total data rate of more than 3 Tbit/s for the upgraded VELO. The detector modules are located in a separate vacuum, separate...

  11. The LHCb hadron calorimeter

    International Nuclear Information System (INIS)

    Dzhelyadin, R.I.

    2002-01-01

    The Hadron Calorimeter (HCAL) is designed for the LHCb experiment. The main purpose of the detector is to provide data for the L0 hadron trigger. The HCAL is designed as consisting of two symmetric movable parts of about 500 ton in total getting in touch in operation position without non-instrumented zones. The lateral dimensions of an active area are X=8.4 m width, Y=6.8 m height, and is distanced from the interaction point at Z=13.33 m. Both halves are assembled from stacked up modules. An internal structure consisting of thin iron plates interspaced with scintillating tiles has been chosen. Attention is paid to optimize the detector according to the requirements of the experiment, reducing the spending needed for its construction. Different construction technologies are being discussed. The calorimeter properties have been extensively studied with a variety of prototype on the accelerator beam. The calibration with a radioactive source and module-0 construction experience is discussed

  12. The LHCb Data Management System

    International Nuclear Information System (INIS)

    Baud, J P; Charpentier, Ph; Ciba, K; Lanciotti, E; Màthè, Z; Graciani, R; Remenska, D; Santana, R

    2012-01-01

    The LHCb Data Management System is based on the DIRAC Grid Community Solution. LHCbDirac provides extensions to the basic DMS such as a Bookkeeping System. Datasets are defined as sets of files corresponding to a given query in the Bookkeeping system. Datasets can be manipulated by CLI tools as well as by automatic transformations (removal, replication, processing). A dynamic handling of dataset replication is performed, based on disk space usage at the sites and dataset popularity. For custodial storage, an on-demand recall of files from tape is performed, driven by the requests of the jobs, including disk cache handling. We shall describe the tools that are available for Data Management, from handling of large datasets to basic tools for users as well as for monitoring the dynamic behavior of LHCb Storage capacity.

  13. LHCb: Machine assisted histogram classification

    CERN Multimedia

    Somogyi, P; Gaspar, C

    2009-01-01

    LHCb is one of the four major experiments under completion at the Large Hadron Collider (LHC). Monitoring the quality of the acquired data is important, because it allows the verification of the detector performance. Anomalies, such as missing values or unexpected distributions can be indicators of a malfunctioning detector, resulting in poor data quality. Spotting faulty components can be either done visually using instruments such as the LHCb Histogram Presenter, or by automated tools. In order to assist detector experts in handling the vast monitoring information resulting from the sheer size of the detector, a graph-theoretic based clustering tool, combined with machine learning algorithms is proposed and demonstrated by processing histograms representing 2D event hitmaps. The concept is proven by detecting ion feedback events in the LHCb RICH subdetector.

  14. The LHCb Silicon Inner Tracker

    International Nuclear Information System (INIS)

    Sievers, P.

    2002-01-01

    A silicon strip detector has been adopted as baseline technology for the LHCb Inner Tracker system. It consists of nine planar stations covering a cross-shaped area around the LHCb beam pipe. Depending on the final layout of the stations the sensitive surface of the Inner Tracker will be of the order of 14 m 2 . Ladders have to be 22 cm long and the pitch of the sensors should be as large as possible in order to reduce costs of the readout electronics. Major design criteria are material budget, short shaping time and a moderate spatial resolution of about 80 μm. After an introduction on the requirements of the LHCb Inner Tracker we present a description and characterization of silicon prototype sensors. First, laboratory and test beam results are discussed

  15. Software for the LHCb experiment

    CERN Document Server

    Corti, Gloria; Belyaev, Ivan; Cattaneo, Marco; Charpentier, Philippe; Frank, Markus; Koppenburg, Patrick; Mato-Vila, P; Ranjard, Florence; Roiser, Stefan

    2006-01-01

    LHCb is an experiment for precision measurements of CP-violation and rare decays in B mesons at the LHC collider at CERN. The LHCb software development strategy follows an architecture-centric approach as a way of creating a resilient software framework that can withstand changes in requirements and technology over the expected long lifetime of the experiment. The software architecture, called GAUDI, supports event data processing applications that run in different processing environments ranging from the real-time high- level triggers in the online system to the final physics analysis performed by more than one hundred physicists. The major architectural design choices and the arguments that lead to these choices will be outlined. Object oriented technologies have been used throughout. Initially developed for the LHCb experiment, GAUDI has been adopted and extended by other experiments. Several iterations of the GAUDI software framework have been released and are now being used routinely by the physicists of...

  16. Potentialities of the LHCb experiment for the discovery of the physics beyond the standard model in the B{sub d}{sup 0} {yields} {phi}K{sub S}{sup 0} decay; Etude du potentiel de l'experience LHCb pour la decouverte de physique au-dela du modele standard dans la desintegration B{sub d}{sup 0} {yields} {phi}K{sub S}{sup 0}

    Energy Technology Data Exchange (ETDEWEB)

    Viaud, B

    2003-10-01

    The Standard Model predicts the same time-dependant CP asymmetry in both B{sub d}{sup 0} -> J/{psi}K{sub S}{sup 0} and B{sub d}{sup 0} {yields} {phi}K{sub S}{sup 0} decays. This asymmetry is proportional to sin(2*{beta}). Any difference between the CP asymmetries measured in these 2 channels would indicate the presence of new phenomena beyond the Standard Model. We study the sensitivity of the LHCb experiment to this effect. To that end, we estimate the statistical error on the measurement of sin(2*{beta}) in the B{sub d}{sup 0} {yields} {phi}K{sub S}{sup 0} channel by LHCb. We do that with the LHCb classic detector, and then with the re-optimized detector. The number of simulated background events is too small with respect to the annual statistics to obtain precise evaluations. We developed several methods to improve these evaluations. In the most optimistic case, we predict that sin(2*{beta}) would be measured in the LHCb classic configuration with a statistical error equal to 0.56. With the re-optimized detector, this error is further improved: 0.29. (author)

  17. Potentialities of the LHCb experiment for the discovery of the physics beyond the standard model in the B{sub d}{sup 0} {yields} {phi}K{sub S}{sup 0} decay; Etude du potentiel de l'experience LHCb pour la decouverte de physique au-dela du modele standard dans la desintegration B{sub d}{sup 0} {yields} {phi}K{sub S}{sup 0}

    Energy Technology Data Exchange (ETDEWEB)

    Viaud, B

    2003-10-01

    The Standard Model predicts the same time-dependant CP asymmetry in both B{sub d}{sup 0} -> J/{psi}K{sub S}{sup 0} and B{sub d}{sup 0} {yields} {phi}K{sub S}{sup 0} decays. This asymmetry is proportional to sin(2*{beta}). Any difference between the CP asymmetries measured in these 2 channels would indicate the presence of new phenomena beyond the Standard Model. We study the sensitivity of the LHCb experiment to this effect. To that end, we estimate the statistical error on the measurement of sin(2*{beta}) in the B{sub d}{sup 0} {yields} {phi}K{sub S}{sup 0} channel by LHCb. We do that with the LHCb classic detector, and then with the re-optimized detector. The number of simulated background events is too small with respect to the annual statistics to obtain precise evaluations. We developed several methods to improve these evaluations. In the most optimistic case, we predict that sin(2*{beta}) would be measured in the LHCb classic configuration with a statistical error equal to 0.56. With the re-optimized detector, this error is further improved: 0.29. (author)

  18. LHCB : The upgraded LHCb RICH detector: status and perspectives

    CERN Multimedia

    Cardinale, Roberta

    2015-01-01

    The LHCb experiment is designed to perform high-precision measurements of CP violation and search for New Physics using the enormous flux of beauty and charmed hadrons produced at the Large Hadron Collider (LHC). The two RICH detectors installed in LHCb have performed successfully during the 2010-2012 data taking period. The data from these detectors were essential to most of the physics results published by LHCb. In order to extend its potential for discovery and study of new phenomena it is planned to upgrade the LHCb experiment in 2018 with a 40MHz readout and a much more flexible software-based triggering system. This would increase the readout rate and occupancies for the RICH detectors. The RICH detector will require new photon detectors and modifications of the optics of the upstream RICH detector. Tests of the complete opto-electronic chain have been performed during testbeam sessions in autumn 2014. The status and perspectives of the RICH upgrade project will be presented.

  19. LHCb New algorithms for Flavour Tagging at the LHCb experiment

    CERN Multimedia

    Fazzini, Davide

    2016-01-01

    The Flavour Tagging technique allows to identify the B initial flavour, required in the measurements of flavour oscillations and time-dependent CP asymmetries in neutral B meson systems. The identification performances at LHCb are further enhanced thanks to the contribution of new algorithms.

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

    International Nuclear Information System (INIS)

    Collins, P.

    2013-01-01

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

  1. LHCb : The LHCb trigger system and its upgrade

    CERN Multimedia

    Dziurda, Agnieszka

    2015-01-01

    The current LHCb trigger system consists of a hardware level, which reduces the LHC inelastic collision rate of 30 MHz to 1 MHz, at which the entire detector is read out. In a second level, implemented in a farm of 20k parallel-processing CPUs, the event rate is reduced to about 5 kHz. We review the performance of the LHCb trigger system during Run I of the LHC. Special attention is given to the use of multivariate analyses in the High Level Trigger. The major bottleneck for hadronic decays is the hardware trigger. LHCb plans a major upgrade of the detector and DAQ system in the LHC shutdown of 2018, enabling a purely software based trigger to process the full 30 MHz of inelastic collisions delivered by the LHC. We demonstrate that the planned architecture will be able to meet this challenge. We discuss the use of disk space in the trigger farm to buffer events while performing run-by-run detector calibrations, and the way this real time calibration and subsequent full event reconstruction will allow LHCb to ...

  2. LHCb VELO upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Hennessy, Karol

    2017-02-11

    The upgrade of the LHCb experiment, scheduled for LHC Run-III, scheduled to start in 2021, will transform the experiment to a trigger-less system reading out the full detector at 40 MHz event rate. All data reduction algorithms will be executed in a high-level software farm enabling the detector to run at luminosities of 2×10{sup 33} cm{sup −2} s{sup −1}. The Vertex Locator (VELO) is the silicon vertex detector surrounding the interaction region. The current detector will be replaced with a hybrid pixel system equipped with electronics capable of reading out at 40 MHz. The upgraded VELO will provide fast pattern recognition and track reconstruction to the software trigger. The silicon pixel sensors have 55×55 μm{sup 2} pitch, and are read out by the VeloPix ASIC, from the Timepix/Medipix family. The hottest region will have pixel hit rates of 900 Mhits/s yielding a total data rate of more than 3 Tbit/s for the upgraded VELO. The detector modules are located in a separate vacuum, separated from the beam vacuum by a thin custom made foil. The foil will be manufactured through milling and possibly thinned further by chemical etching. The material budget will be minimised by the use of evaporative CO{sub 2} coolant circulating in microchannels within 400 μm thick silicon substrates. The current status of the VELO upgrade is described and latest results from operation of irradiated sensor assemblies are presented.

  3. LHCb time-dependent results

    OpenAIRE

    Calvi, Marta

    2011-01-01

    This review reports preliminary results of time-dependent measurements of decays of $B^0$ mesons and $B^0_s$ mesons coming from the analysis of about 36 pb$^{-1}$ of data collected by the LHCb experiment during the 2010 run of the Large Hadron Collider at $\\sqrt{s}$ = 7 TeV.

  4. LHCb time-dependent results

    OpenAIRE

    Calvi, Marta; Collaboration, for the LHCb

    2011-01-01

    This review reports preliminary results of time-dependent measurements of decays of B^0 mesons and B^0_s mesons coming from the analysis of about 36 pb^-1 of data collected by the LHCb experiment during the 2010 run of the Large Hadron Collider at sqrt(s)=7 TeV.

  5. Exotic meson studies at LHCb

    Directory of Open Access Journals (Sweden)

    Kreps Michal

    2014-01-01

    Full Text Available The latest years have seen a resurrection of interest in searches for exotic states motivated by tantalising observations of several states. Using the pp collisions data collected at 7 and 8 TeV by the LHCb experiment, we performed studies of the X(3872 decay rate to ψ (2Sγ final state, as well as confirmation the Z(4430+ state.

  6. Forward Top Physics at LHCb

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    The first Run 2 measurement of top pair production in the dilepton channel at 13 TeV will be presented, along with previous Run 1 measurements in final states accessible to both single top and top pair production. Heavy flavour tagging strategies at LHCb will also be discussed.

  7. DIRAC reliable data management for LHCb

    CERN Document Server

    Smith, A C

    2008-01-01

    DIRAC, LHCb's Grid Workload and Data Management System, utilizes WLCG resources and middleware components to perform distributed computing tasks satisfying LHCb's Computing Model. The Data Management System (DMS) handles data transfer and data access within LHCb. Its scope ranges from the output of the LHCb Online system to Grid-enabled storage for all data types. It supports metadata for these files in replica and bookkeeping catalogues, allowing dataset selection and localization. The DMS controls the movement of files in a redundant fashion whilst providing utilities for accessing all metadata. To do these tasks effectively the DMS requires complete self integrity between its components and external physical storage. The DMS provides highly redundant management of all LHCb data to leverage available storage resources and to manage transient errors in underlying services. It provides data driven and reliable distribution of files as well as reliable job output upload, utilizing VO Boxes at LHCb Tier1 sites ...

  8. LHCb: Fabric Management with Diskless Servers and Quattor on LHCb

    CERN Multimedia

    Schweitzer, P; Brarda, L; Neufeld, N

    2011-01-01

    Large scientific experiments nowadays very often are using large computer farms to process the events acquired from the detectors. In LHCb a small sysadmin team manages 1400 servers of the LHCb Event Filter Farm, but also a wide variety of control servers for the detector electronics and infrastructure computers: file servers, gateways, DNS, DHCP and others. This variety of servers could not be handled without a solid fabric management system. We choose the Quattor toolkit for this task. We will present our use of this toolkit, with an emphasis on how we handle our diskless nodes (Event filter farm nodes and computers embedded in the acquisition electronic cards). We will show our current tests to replace the standard (RedHat/Scientific Linux) way of handling diskless nodes to fusion filesystems and how it improves fabric management.

  9. LHCb: First year of running for the LHCb calorimeter system

    CERN Multimedia

    Guz, Y

    2011-01-01

    The LHCb experiment is dedicated to precision measurements of CP violation and rare decays of B hadrons at the Large Hadron Collider (LHC) at CERN (Geneva) [1, 2]. LHCb is a single-arm spectrometer with a forward angular coverage from approximately 10 mrad to 300 mrad. It comprises a calorimeter system composed of four subdetectors [3]. It selects transverse energy hadron, electron and photon candidates for the first trigger level (L0), which makes a decision 4µs after the interaction. It provides the identification of electrons, photons and hadrons as well as the measurement of their energies and positions. The set of constraints resulting from these functionalities defines the general structure and the main characteristics of the calorimeter system and its associated electronics. A classical structure of an electromagnetic calorimeter (ECAL) followed by a hadron calorimeter (HCAL) has been adopted. In addition the system includes in front of them the Scintillating Pad Detector (SPD) and Pre-Showe...

  10. LHCb - Novel Muon Identification Algorithms for the LHCb Upgrade

    CERN Multimedia

    Cogoni, Violetta

    2016-01-01

    The present LHCb Muon Identification procedure was optimised to guarantee high muon detection efficiency at the istantaneous luminosity $\\mathcal{L}$ of $2\\cdot10^{32}$~cm$^{-2}$~s$^{-1}$. In the current data taking conditions, the luminosity is higher than foreseen and the low energy background contribution to the visible rate in the muon system is larger than expected. A worse situation is expected for Run III when LHCb will operate at $\\mathcal{L} = 2\\cdot10^{33}$~cm$^{-2}$~s$^{-1}$ causing the high particle fluxes to deteriorate the muon detection efficiency, because of the increased dead time of the electronics, and in particular to worsen the muon identification capabilities, due to the increased contribution of the background, with deleterious consequences especially for the analyses requiring high purity signal. In this context, possible new algorithms for the muon identification will be illustrated. In particular, the performance on combinatorial background rejection will be shown, together with the ...

  11. LHCb-The LHCb trigger in Run II

    CERN Multimedia

    Michielin, Emanuele

    2016-01-01

    The LHCb trigger system has been upgraded to exploit the real-time alignment, calibration and analysis capabilities of LHCb in Run-II. An increase in the CPU and disk capacity of the event filter farm, combined with improvements to the reconstruction software, mean that efficient, exclusive selections can be made in the first stage of the High Level Trigger (HLT1). The output of HLT1 is buffered to the 5 PB of disk on the event filter farm, while the detector is aligned and calibrated in real time. The second stage, HLT2, performs complete, offline quality, event reconstruction. Physics analyses can be performed directly on this information, and for the majority of charm physics selections, a reduced event format can be written out, which permits higher event rates.

  12. LHCb Measurement of the CKM angle $\\gamma$ at LHCb

    CERN Multimedia

    Ali, S

    2014-01-01

    In this poster we present the latest result by the LHCb collaboration in determining the CKM angle $\\gamma$ ($(67.1 \\pm 12)^{\\circ}$). The result is determined by combining several $B \\to Dh$ analyses. Latest results from the decay time dependent $B_{s} \\to D_{s}K$ analysis is also reported, along with a few other decay channels interesting for determination of $\\gamma$ in the future.

  13. LHCb: Measurement of $b$-hadron lifetimes at LHCb

    CERN Multimedia

    Amhis, Y

    2014-01-01

    Lifetimes are among the most fundamental properties of elementary particles. Precision Measurements of $b$-hadron lifetimes are an important tool to test theoretical models such as HQET. These models allow to predict various observables related to B-mixing. Using data collected during Run 1 at the LHC, LHCb measured the lifetime of B-decays including a $J/\\psi$ in the final state.

  14. LHCb: Prospect for rare strange decays at LHCb

    CERN Multimedia

    Marin Benito, C

    2014-01-01

    Prospects on rare strange decays at LHCb are presented. The latest results from the K_s \\to \\mu \\mu search are reported, together with the future prospects for this decay. A search for K_s \\to \\pi^0 \\mu \\mu, a K^+ mass measurement, a search for K_s \\to 4 \\el and a search for \\Sigma^+ \\to p\\mu\\mu are also presented.

  15. LHCb: Experience with LHCb alignment software on first data

    CERN Multimedia

    Deissenroth, M

    2009-01-01

    We report results obtained with different track-based algorithms for the alignment of the LHCb detector with first data. The large-area Muon Detector and Outer Tracker have been aligned with a large sample of tracks from cosmic rays. The three silicon detectors --- VELO, TT-station and Inner Tracker --- have been aligned with beam-induced events from the LHC injection line. We compare the results from the track-based alignment with expectations from detector survey.

  16. LHCbDIRAC as Apache Mesos microservices

    OpenAIRE

    Haen, Christophe; Couturier, Benjamin

    2017-01-01

    The LHCb experiment relies on LHCbDIRAC, an extension of DIRAC, to drive its offline computing. This middleware provides a development framework and a complete set of components for building distributed computing systems. These components are currently installed and run on virtual machines (VM) or bare metal hardware. Due to the increased workload, high availability is becoming more and more important for the LHCbDIRAC services, and the current installation model is showing its limitations. A...

  17. LHCb: The LHCb Trigger Architecture beyond LS1

    CERN Multimedia

    Albrecht, J; Neubert, S; Raven, G; Sokoloff, M D; Williams, M

    2013-01-01

    The LHCb experiment is a spectrometer dedicated to the study of heavy flavor at the LHC. The rate of proton-proton collisions at the LHC is 15 MHz, but resource limitations mean that only 5 kHz can be written to storage for offline analytsis. For this reason the LHCb data acquisition system -- trigger -- plays a key role in selecting signal events and rejecting background. In contrast to previous experiments at hadron colliders like for example CDF or D0, the bulk of the LHCb trigger is implemented in software and deployed on a farm of 20k parallel processing nodes. This system, called the High Level Trigger (HLT) is responsible for reducing the rate from the maximum at which the detector can be read out, 1.1 MHz, to the 5 kHz which can be processed offline,and has 20 ms in which to process and accept/reject each event. In order to minimize systematic uncertainties, the HLT was designed from the outset to reuse the offline reconstruction and selection code. During the long shutdown it is proposed to extend th...

  18. b-JETS AT LHCb

    CERN Document Server

    Coco, Victor

    2008-01-01

    LHCb 1 is a LHC experiment dedicated to pre-jets. LHCh detector is a one arm spectrometer. It covers the forward region of interaction point, from 30 mrad to 300 (250) mrad in bending (non-bending) plane. The choice of such a limited acceptance is motivated by the fact that most of the 500 µb correlated bb pairs are produced in this region. LHCb experiment will take data at a luminosity of 2 x ID32cm-2s-1, where bunch crossing are dominated by single pp interactions. Good particle identification, excellent tracking and vcrtcxing arc needed for B physic mcasurmcnts. Expected resolution on track momentum is about bp/p = 0.35% around 10 GeV /c to bp/p = 0.55% around 140 GeV /c. Impact parameter resolution is expected to be aIP = 14µm + 35µm/p-r.

  19. Rare B decays at LHCb

    CERN Document Server

    Puig Navarro, Albert

    2017-01-01

    Rare decays are flavour changing neutral current processes that allow sensitive searches for phenomena beyond the Standard Model (SM). In the SM, rare decays are loop-suppressed and new particles in SM extensions can give significant contributions. The very rare decay $B^0_s\\to\\mu^+\\mu^-$ in addition helicity suppressed and constitutes a powerful probe for new (pseudo) scalar particles. Of particular interest are furthermore tests of lepton universality in rare $b\\to s\\ell^+\\ell^-$ decays. The LHCb experiment is designed for the study of b-hadron decays and ideally suited for the analysis of rare decays due to its high trigger efficiency, as well as excellent tracking and particle identification performance. Recent results from the LHCb experiment in the area of rare decays are presented, including tests of lepton universality and searches for lepton flavour violation.

  20. LHCb Early Career Scientist Awards

    CERN Multimedia

    Patrick Koppenburg for the LHCb Collaboration

    2016-01-01

    On 15 September 2016, the LHCb collaboration awarded the first set of prizes for outstanding contributions of early career scientists.   From left to right: Guy Wilkinson (LHCb spokesperson), Sascha Stahl, Kevin Dungs, Tim Head, Roel Aaij, Conor Fitzpatrick, Claire Prouvé, Patrick Koppenburg (chair of committee) and Sean Benson. Twenty-five nominations were submitted and considered by the committee, and 5 prizes were awarded to teams or individuals for works that had a significant impact within the last year. The awardees are: Roel Aaij, Sean Benson, Conor Fitzpatrick, Rosen Matev and Sascha Stahl for having implemented and commissioned the revolutionary changes to the LHC Run-2 high-level-trigger, including the first widespread deployment of real-time analysis techniques in High Energy Physics;   Kevin Dungs and Tim Head for having launched the Starterkit initiative, a new style of software tutorials based on modern programming methods. “Starterkit is a group of ph...

  1. On LHCb muon MWPC grounding

    CERN Document Server

    Kashchuk, A

    2006-01-01

    My goal is to study how a big MWPC system, in particular the LHCb muon system, can be protected against unstable operation and multiple spurious hits, produced by incorrect or imperfect grounding in the severe EM environment of the LHCb experiment. A mechanism of penetration of parasitic current from the ground loop to the input of the front-end amplifier is discussed. A new model of the detector cell as the electrical bridge is considered. As shown, unbalance of the bridge makes detector to be sensitive to the noise in ground loop. Resonances in ground loop are specified. Tests of multiple-point and single-point grounding conceptions made on mock-up are presented.

  2. Neutral particles identification at LHCb

    CERN Multimedia

    Quintana, Boris Julien

    2018-01-01

    Important analyses of the core LHCb physics program rely on calorimetry to identify photons, high-energy neutral pions and electrons. For this purpose, the LHCb calorimeter system is composed of a scintillating pad plane, a preshower detector, an electromagnetic and a hadronic sampling calorimeters. The interaction of a given particle in these detectors leaves a specific signature. This is exploited for particle identification (PID) by combining calorimeters and tracking information into multi-variate classifiers. In this contribution, we focus on the identification of photons against high-energy neutral pion and hadronic backgrounds. Performance on Run 1 data will be shown. Small discrepancies with simulation predictions are then discussed, with special emphasis on the methods to correctly estimate PID cut efficiencies by means of large calibration samples of abundant beauty and charm decays to final states with photons. Finally, the technical aspects of the collection of these samples in Run 2 are presented...

  3. LHCb: Self managing experiment resources

    CERN Multimedia

    Stagni, F

    2013-01-01

    Within this paper we present an autonomic Computing resources management system used by LHCb for assessing the status of their Grid resources. Virtual Organizations Grids include heterogeneous resources. For example, LHC experiments very often use resources not provided by WLCG and Cloud Computing resources will soon provide a non-negligible fraction of their computing power. The lack of standards and procedures across experiments and sites generated the appearance of multiple information systems, monitoring tools, ticket portals, etc... which nowadays coexist and represent a very precious source of information for running HEP experiments Computing systems as well as sites. These two facts lead to many particular solutions for a general problem: managing the experiment resources. In this paper we present how LHCb, via the DIRAC interware addressed such issues. With a renewed Central Information Schema hosting all resources metadata and a Status System ( Resource Status System ) delivering real time informatio...

  4. First mass measurements at LHCb

    CERN Multimedia

    Bressieux, J

    2011-01-01

    The LHC opens new frontiers in heavy flavour physics through an unprecedented statistical reach for a variety of interesting states produced in pp collisions. The LHCb spectrometer provides a good mass resolution and is suitable for spectroscopy studies. We present first preliminary mass measurements of several $b$ hadrons and of the exotic $X(3872)$ meson, reconstructed in final states containing a $J/\\psi$ using the data collected in 2010 by the LHCb experiment. An important aspect of the analysis is the calibration of the momentum scale using $J/\\psi \\to \\mu^+ \\mu^-$ decays, as well as the control of systematic uncertainties. While the already very competitive mass measurements for the $B^+$, $B^0$ and $B^0_s$ mesons receive similar contributions from systematic and statistical uncertainties, those of the $\\Lambda_b$, $B^+_c$ and $X(3872)$ particles are dominated by statistical uncertainties, and will therefore substantially improve with more data in the future.

  5. LHCb Upgrade: Scintillating Fibre Tracker

    International Nuclear Information System (INIS)

    Tobin, Mark

    2016-01-01

    The LHCb detector will be upgraded during the Long Shutdown 2 (LS2) of the LHC in order to cope with higher instantaneous luminosities and to read out the data at 40 MHz using a trigger-less read-out system. All front-end electronics will be replaced and several sub-detectors must be redesigned to cope with higher occupancy. The current tracking detectors downstream of the LHCb dipole magnet will be replaced by the Scintillating Fibre (SciFi) Tracker. The SciFi Tracker will use scintillating fibres read out by Silicon Photomultipliers (SiPMs). State-of-the-art multi-channel SiPM arrays are being developed to read out the fibres and a custom ASIC will be used to digitise the signals from the SiPMs. The evolution of the design since the Technical Design Report in 2014 and the latest R & D results are presented.

  6. LHCb Exotica and Higgs searches

    CERN Multimedia

    Lucchesi, Donatella

    2016-01-01

    The unique phase space coverage and features of the LHCb detector at the LHC makes it an ideal environment to probe complementary New Physics parameter regions. In particular, recently developed jet tagging algorithms are ideal for searches involving $b$ and $c$ jets. This poster will review different jet-related exotica searches together with the efforts in the search for a Higgs boson decaying to a pair of heavy quarks.

  7. Central Exclusive Production at LHCb

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00392425

    2017-01-01

    The LHCb detector, with its excellent momentum resolution and flexible trigger strategy, is ideally suited for measuring particles produced exclusively. In addition, a new system of forward shower counters has been installed upstream and downstream of the detector, and has been used to facilitate studies of Central Exclusive Production. Such measurements of integrated and differential cross-section in both Run 1 and Run 2 of the LHC, are summarised here.

  8. Fast calorimeter simulation in LHCb

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    Fast calorimeter simulation in LHCb In HEP experiments CPU resources required by MC simulations are constantly growing and become a very large fraction of the total computing power (greater than 75%). At the same time the pace of performance improvements from technology is slowing down, so the only solution is a more efficient use of resources. Efforts are ongoing in the LHC experiments to provide multiple options for simulating events in a faster way when higher statistics is needed. A key of the success for this strategy is the possibility of enabling fast simulation options in a common framework with minimal action by the final user. In this talk we will describe the solution adopted in Gauss, the LHCb simulation software framework, to selectively exclude particles from being simulated by the Geant4 toolkit and to insert the corresponding hits generated in a faster way. The approach, integrated within the Geant4 toolkit, has been applied to the LHCb calorimeter but it could also be used for other subdetec...

  9. Virtualization for the LHCb experiment

    International Nuclear Information System (INIS)

    Bonaccorsi, E.; Brarda, L.; Chebbi, M.; Neufeld, N.; Sborzacci, F.

    2012-01-01

    The LHCb experiment, one of the 4 large particle detector at CERN, counts in its Online System more than 2000 servers and embedded systems. As a result of ever-increasing CPU performance in modern servers, many of the applications in the controls system are excellent candidates for virtualization technologies. We see virtualization as an approach to cut down cost, optimize resource usage and manage the complexity of the IT infrastructure of LHCb. Recently we have added a Kernel Virtual Machine (KVM) cluster based on Red Hat Enterprise Virtualization for Servers (RHEV) complementary to the existing Hyper-V cluster devoted only to the virtualization of the windows guests. This paper describes the architecture of our solution based on KVM and RHEV as along with its integration with the existing Hyper-V infrastructure and the Quattor cluster management tools and in particular how we use to run controls applications on a virtualized infrastructure. We present performance results of both the KVM and Hyper-V solutions, problems encountered and a description of the management tools developed for the integration with the Online cluster and LHCb SCADA control system based on PVSS. (authors)

  10. Highlights from the LHCb ion physics program

    International Nuclear Information System (INIS)

    Schmelling, Michael

    2017-01-01

    Following the successful participation of LHCb in the 2013 proton-lead run of the LHC, in 2015 the collaboration decided to further extend its physics program to study also lead-lead collisions and fixed target interactions. These proceedings discuss the physics reach of the detector and the first results from the LHCb ion physics and fixed target program. (paper)

  11. Study of Pentaquark States at LHCb

    CERN Document Server

    Yang, Zhenwei

    2016-01-01

    The observation of the two resonances consistent with charmonium-like pentaquark states, Pc(4380)+ and Pc(4450)+, by the LHCb collaboration inspires enthusiasm in particle physics. This article briefly reports about the observation and the experimental study of the pentaquark states by the LHCb collaboration

  12. A symphony of data at LHCb

    CERN Multimedia

    2008-01-01

    Like musical instruments in an orchestra, the main difficulty with the many detectors of LHCb is coaxing them into playing in harmony. On 8 February 2008, for the first time, the LHCb control room team managed to extract a symphony of data from an almost complete ensemble of LHCb detectors. The LHCb control room team examining the data read out from the LHCb detectors. General view of the LHCb detector components.Now that all the detectors of LHCb are installed in the cavern they can begin to play a tune. The week of 4 February was commissioning week for the LHCb control room, when, for the first time, data from the majority of the sub-detectors (VELO, RICH 1, RICH 2, ECAL, HCAL, MUON, L0Calo and L0DU) was read out, controlled from a single window on the main computer. Sixty electronic boards, which read out the fragments of triggered events, were used during the readout at a frequency of 100 Hz. As not all of the boards ...

  13. ALICE & LHCb: refinements for the restart

    CERN Multimedia

    2009-01-01

    Following the previous issue, the Bulletin continues its series to find out what the six LHC experiments have been up to since last September, and how they are preparing for the restart. Previously we looked at CMS and ATLAS; this issue we will round up the past 10 months of activity at ALICE and LHCb. LHCb The cavern of the LHCb experiment. This year has given LHCb the chance to install the 5th and final plane of muon chambers, which will improve the triggering at nominal luminosity. This is the final piece of the experiment to be installed. "Now the detector looks exactly as it does in the technical design report," confirms Andrei Golutvin, LHCb Spokesperson. "We also took advantage of this shutdown to make several improvements. For example, we modified the high voltage system of the electromagnetic calorimeter to reduce noise further to a negligible level. We also took some measures to improve ...

  14. No mission is impossible for LHCb

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    Time: 01:37:51 am, 3 October, 2011. The LHC is producing million collisions per second in its detectors. But at that time, one collision is “more special” than the others in the LHCb detector: the milestone of 1 inverse femtobarn of luminosity is surpassed. What was considered as “mission impossible” at the beginning of the year is now “mission accomplished”.   Mike Lamont (Operations Group Leader), Pierluigi Campana (LHCb Spokesperson), Steve Myers (Director for Accelerators and Technology), and Paul Collier (Head of the Beams Department) celebrate the LHCb milestone. LHCb is the CERN experiment specialising in the study of b-quarks, whose properties and behaviour are likely to provide physicists with important hints on several physics processes, including some new physics. “One inverse femtobarn of luminosity corresponds to about seventy billion b-quark pairs decayed in the LHCb detector,” explains Pierluigi Cam...

  15. Plans and status of the LHCb upgrade

    CERN Document Server

    Szumlak, Tomasz

    2017-01-01

    LHCb (Large Hadron Collider beauty) is a high precision experiment dedicated to searching for New Physics beyond the Standard Model in the heavy flavour sector. Since LHCb is optimised to perf orm indirect studies and is sensitive to mass scales potentially larger than the LHC energy it is playing a key role in broad searches for New Physics phenomena. This expectation is supported by many intriguing anomalies, especially related to rare decays and lepton flavour universality, observed and reported by LHCb. Thus, it is essential for LHCb to enter the high luminosity phase and continue data taking beyond LHC Long Shutdown 2 (LS2). The LHCb experimental setup will undergo a major upgrade that is be ing planned for the LHC Run 3. Here we will discuss selected aspects of this project.

  16. Implementing database system for LHCb publications page

    CERN Document Server

    Abdullayev, Fakhriddin

    2017-01-01

    The LHCb is one of the main detectors of Large Hadron Collider, where physicists and scientists work together on high precision measurements of matter-antimatter asymmetries and searches for rare and forbidden decays, with the aim of discovering new and unexpected forces. The work does not only consist of analyzing data collected from experiments but also in publishing the results of those analyses. The LHCb publications are gathered on LHCb publications page to maximize their availability to both LHCb members and to the high energy community. In this project a new database system was implemented for LHCb publications page. This will help to improve access to research papers for scientists and better integration with current CERN library website and others.

  17. LHCb: Evaluation of the Radiation Environment of the LHCb Experiment

    CERN Multimedia

    Karacson, M

    2011-01-01

    The characterization of all aspects of the radiation field of the LHCb experiment is needed to understand the impact of the unprecedented radiation levels to which its detector and electronics are exposed to. The methodology on how this is done is described. Analysis of the measurements of active and passive sensors of various types which are distributed in and around the detector will be carried out. Appropriate cross calibrations will be applied and comparisons between them will be performed. Critical comparisons with simulation results obtained with the FLUKA Monte Carlo code are also an essential element of the study.

  18. LHCb: Measurement of $D^{\\pm}$ Production Asymmetry at LHCb

    CERN Multimedia

    Xing, Zhou

    2012-01-01

    Heavy quark production in 7 TeV pp collisions at the LHC need not be flavour symmetric. Here the production asymmetry, $A_p$ , between $D_s^+$ and $D_s^-$ mesons is measured using the $\\phi\\pi$ decay mode. The difference between $\\pi^+$ and $\\pi^-$ detection efficiencies is measured using the ratio of fully reconstructed to partially reconstructed $D^*$ decays. Using 1 fb$^{-1}$ of data collected with the LHCb detector, we find $A_p = (-0.39 \\pm 0.22 \\pm 0.08)$%.

  19. Prospects for time-dependent asymmetries at LHCb

    CERN Document Server

    INSPIRE-00260500

    2012-01-01

    LHCb is already providing leading measurements of time-dependent CP asymmetries with 1 fb$^{-1}$ of data. With the LHCb detector, and further one with the LHCb upgrade, very high-precision time-dependent CP measurements are expected to stringently test the CKM paradigm and to the search for possible small NP effects. A review of the current precision and the prospects for these time-dependent quantities with the LHCb and LHCb upgraded detectors are summarised in this paper.

  20. LHCB RICH gas system proposal

    CERN Document Server

    Bosteels, Michel; Haider, S

    2001-01-01

    Both LHCb RICH will be operated with fluorocarbon as gas radiator. RICH 1 will be filled with 4m^3 of C4F10 and RICH 2 with 100m^3 of CF4. The gas systems will run as a closed loop circulation and a gas recovery system within the closed loop is planned for RICH 1, where the recovery of the CF4 will only be realised during filling and emptying of the detector. Inline gas purification is foreseen for the gas systems in order to limit water and oxygen impurities.

  1. CO$_2$ cooling experience (LHCb)

    CERN Document Server

    Van Lysebetten, Ann; Verlaat, Bart

    2007-01-01

    The thermal control system of the LHCb VErtex LOcator (VELO) is a two-phase C0$_2$ cooling system based on the 2-Phase Accumulator Controlled Loop (2PACL) method. Liquid carbon dioxide is mechanically pumped in a closed loop, chilled by a water-cooled freon chiller and evaporated in the VELO detector. The main goal of the system is the permanent cooling of the VELO silicon sensors and of the heat producing front-end electronics inside a vacuum environment. This paper describes the design and the performance of the system. First results obtained during commissioning are also presented.

  2. Hadronic B decays at LHCb

    International Nuclear Information System (INIS)

    Latham, T.E.

    2014-01-01

    We present recent results from the analysis of hadronic decays of B s 0 mesons at LHCb detector. The analyses use the data sample collected in 2011, which correspond to an integrated luminosity of 1.0 fb -1 . A large variety of different decays are being studied in order to probe for signs of physics beyond the Standard Model. The statistics available in the 2011 data sample already allow sophisticated analysis techniques, such as the Dalitz-plot analysis and the angular analysis to be employed

  3. Flavour tagging performance in LHCb

    International Nuclear Information System (INIS)

    Grabalosa Gandara, Marc

    2009-01-01

    To do precise CP violation measurements, the best possible determination of the flavour of the B-meson is necessary. This report summarizes the flavour tagging performances for the LHCb experiment. The flavour tagging is obtained through a combination of several methods, based on different signatures. The use of control channels, which are decays to flavour-specific final states, will allow to determine the wrong tag fraction ω (the probability of a tag to be wrong), which can be used as an input for the determination of CKM unitarity triangle angles.

  4. LHCb DAQ network upgrade tests

    CERN Document Server

    Pisani, Flavio

    2013-01-01

    My project concerned the evaluation of new technologies for the DAQ network upgrade of LHCb. The first part consisted in developing and Open Flow-based Clos network. This new technology is very interesting and powerful but, as shown by the results, it still needs further improvements. The second part consisted in testing and benchmarking 40GbE network equipment: Mellanox MT27500, Chelsio T580 and Huawei Cloud Engine 12804. An event-building simulation is currently been performed in order to check the feasibility of the DAQ network upgrade in LS2. The first results are promising.

  5. LHCb: The LHCb off-Site HLT Farm Demonstration

    CERN Multimedia

    Liu, Guoming

    2012-01-01

    The LHCb High Level Trigger (HLT) farm consists of about 1300 nodes, which are housed in the underground server room of the experiment point. Due to the constraints of the power supply and cooling system, it is difficult to install more servers in this room for the future. Off-site computing farm is a solution to enlarge the computing capacity. In this paper, we will demonstrate the LHCb off-site HLT farm which locate in the CERN computing center. Since we use private IP addresses for the HLT farm, we would need virtual private network (VPN) to bridge both sites. There are two kinds of traffic in the event builder: control traffic for the control and monitoring of the farm and the Data Acquisition (DAQ) traffic. We adopt IP tunnel for the control traffic and Network Address Translate (NAT) for the DAQ traffic. The performance of the off-site farm have been tested and compared with the on-site farm. The effect of the network latency has been studied. To employ a large off-site farm, one of the potential bottle...

  6. LHCb: Time structure analysis of the LHCb Online network

    CERN Multimedia

    Antichi, G; Campora Perez, D H; Liu, G; Neufeld, N; Giordano, S; Owezarski, P; Moore, A

    2013-01-01

    The LHCb Online Network is a real time high performance network, in which 350 data sources send data over a Gigabit Ethernet LAN to more than 1500 receiving nodes. The aggregated throughput of the application, called Event Building, is more than 60 GB/s. The protocol employed by LHCb makes the sending nodes transmit simultaneously portions of events to one receiving node at a time, which is selected using a credit-token scheme. The resulting traffic is very bursty and sensitive to irregularities in the temporal distribution of packet-bursts to the same destination or region of the network. In order to study the relevant properties of such a dataflow, a non-disruptive monitoring setup based on a networking capable FPGA (NetFPGA) has been deployed. The NetFPGA allows order of hundred nano-second precise time-stamping of packets. We study in detail the timing structure of the Event Building communication, and we identify potential effects of micro-bursts like buffer packet drops or jitter.

  7. LHCb: $2\\beta_s$ measurement at LHCb

    CERN Multimedia

    Conti, G

    2009-01-01

    A measurement of $2\\beta_s$, the phase of the $B_s-\\bar{B_s}$ oscillation amplitude with respect to that of the ${\\rm b} \\rightarrow {\\rm c^{+}}{\\rm W^{-}}$ tree decay amplitude, is one of the key goals of the LHCb experiment with first data. In the Standard Model (SM), $2\\beta_s$ is predicted to be $0.0360^{+0.0020}_{-0.0016} \\rm rad$. The current constraints from the Tevatron are: $2\\beta_{s}\\in[0.32 ; 2.82]$ at 68$\\%$CL from the CDF experiment and $2\\beta_{s}=0.57^{+0.24}_{-0.30}$ from the D$\\oslash$ experiment. Although the statistical uncertainties are large, these results hint at the possible contribution of New Physics in the $B_s-\\bar{B_s}$ box diagram. After one year of data taking at LHCb at an average luminosity of $\\mathcal{L}\\sim2\\cdot10^{32}\\rm cm^{-2} \\rm s^{-1}$ (integrated luminosity $\\mathcal{L}_{\\rm int}\\sim 2 \\rm fb^{-1}$), the expected statistical uncertainty on the measurement is $\\sigma(2\\beta_s)\\simeq 0.03$. This uncertainty is similar to the $2\\beta_s$ value predicted by the SM.

  8. LHCb: LHCb Muon System Performance at High Luminosity

    CERN Multimedia

    Pinci, D

    2013-01-01

    The LHCb detector was conceived to operate with an average Luminosity of $2 \\times 10^{32}$ cm$^{-2}$ s$^{-1}$. During the last year of LHC run, the whole apparatus has shown to be able to perfectly acquire and manage data produced at a Luminosity as high as $4 \\times 10^{32}$ cm$^{-2}$ s$^{-1}$. In these conditions, all sub-detectors operated at average particle rates higher than the design ones and in particular the Multi-Wire Proportional Chambers equipping the Muon System had to sustain a particle rate as high as 250 kHz/cm$^{2}$. In order to study the possibility of increasing the Luminosity of operation of the whole experiment several tests were performed. The effective beam Luminosity at the interaction point of LHCb was increased in several steps up to $10^{33}$ cm$^{-2}$ s$^{-1}$ and in each step the behavior of all the detectors in the Muon System was recorded. The data analysis has allowed to study the performance of the Muon System as a function of the LHC Luminosity and the results are r...

  9. Mesure des couplages trilineaires anomaux des bosons de jauge avec le detecteur OPAL au LEP

    Science.gov (United States)

    Trigger, Isabel Marian

    Since 1996, the Large Electron-Positron collider (LEP) at CERN has run at energies sufficiently high for the pair production of electroweak gauge bosons. This permits stringent new tests of the Standard Model of particle physics, which makes very precise predictions of the force and nature of the couplings between these bosons. Two of the possible production processes for W+W- pairs are e+e - --> Z0/γ --> W+W -, which involve W+W-Z 0 and W+W-γ couplings. A detailed study of W+W- events can be used to verify the non-Abelian nature of electroweak interactions, and also, eventually, to probe for phenomena arising from physics beyond the Standard Model. The existence of certain new heavy particles, for example, might result in anomalous couplings. We measure the W+W-Z0 and W+W-γ couplings directly, from the rate of W+W- production in the OPAL detector and from characteristics of the decay product distributions of these events. There are three possible final states for W+W - decays: (i) two oppositely charged leptons and missing energy (W+W- --> l - n l+ n ); (ii)one charged lepton, two jets and missing energy (W+W- --> qq¯l n ); or (iii)four hadronic jets (W+W - --> qq¯qq¯). This thesis principally describes the four-jet decays. This is a complicated final state to reconstruct, as the kinematics of the event must be used to determine which of three possible jet pairings corresponds to the true W+ and W- , and in order to increase the sensitivity to anomalous couplings, it is also necessary to use the charges and momenta of the hadrons in the jets to reconstruct the charge of each W. The angular distributions of the W+/- and of their decay products are directly related to the helicities of the Ws, and provide an insight into the nature of the gauge boson couplings.

  10. LHCb: Optimization and Calibration of Flavour Tagging Algorithms for the LHCb experiment

    CERN Multimedia

    Falabella, A

    2013-01-01

    The LHCb purposes are to make precise measurements of $B$ and $D$ meson decays. In particular in time-dependent CP violation studies the determination of $B$ flavour at production is fundamental. This is known as "flavour tagging" and at LHCb it is performed with several algorithms. The performances and calibration of the flavour tagging algorithms with 2011 data collected by LHCb are reported. Also the performances of the flavour tagging algorithms in the relevant CP violation and asymmetry studies are also reported.

  11. The LHCb Upstream Tracker Project

    CERN Document Server

    Steinkamp, Olaf

    2015-01-01

    The LHCb detector performs searches for New Physics in CP-violating observables and rare heavy-quark decays at the LHC. A comprehensive upgrade is planned for the long shutdown of the LHC in 2018/19. A goal of this upgrade is to abolish hardware triggers and read out the full detector at 40 MHz. This requires to replace the existing TT station upstream of the LHCb magnet by a new silicon micro-strip detector, the Upstream Tracker (UT). The UT will have a new front-end chip compatible with 40 MHz readout, silicon sensors with improved radiation hardness, finer readout granularity, and improved acceptance coverage at small polar angles. The outer region of each detection layer will be covered by p-in-n sensors with 10 cm long strips and a pitch of about 180 mum, while n-in-p sensors with half the pitch and strip length will be employed in the regions of highest particle density close to the beam pipe. The innermost sensors will have a circular cutout to optimize the forward acceptance. The front-end chip is bei...

  12. Charmed meson production at LHCb

    International Nuclear Information System (INIS)

    Müller, Dominik

    2016-01-01

    Measurements of charm meson production are important tests for QCD predictions and LHCb is uniquely suited to perform these measurements in the forward region. This paper summarises recent charm meson production measurements performed by LHCb of J/ψ and open charm mesons and the associated production of ϒ and open charm mesons. The J/ψ and open charm meson measurements are performed with data recorded in Run 2 of the Large Hadron Collider. With proton-proton collisions at √s = 13 TeV, these open a new regime in which QCD predictions for charm meson production may be precisely tested. Furthermore, ratios of cross-sections at different centre-of-mass energies benefit of cancellation of both experimental and theoretical uncertainties, providing a new sensitive test of the QCD calculations. Measurements of ϒ and open charm meson associated production are performed using √s = 7 TeV and √s = 8 TeV data and constitute the first observation of this production channel.

  13. LHCb online infrastructure monitoring tools

    International Nuclear Information System (INIS)

    Granado Cardoso, L.; Gaspar, C.; Haen, C.; Neufeld, N.; Varela, F.; Galli, D.

    2012-01-01

    The Online System of the LHCb experiment at CERN is composed of a very large number of PCs: around 1500 in a CPU farm for performing the High Level Trigger; around 170 for the control system, running the SCADA system - PVSS; and several others for performing data monitoring, reconstruction, storage, and infrastructure tasks, like databases, etc. Some PCs run Linux, some run Windows but all of them need to be remotely controlled and monitored to make sure they are correctly running and to be able, for example, to reboot them whenever necessary. A set of tools was developed in order to centrally monitor the status of all PCs and PVSS Projects needed to run the experiment: a Farm Monitoring and Control (FMC) tool, which provides the lower level access to the PCs, and a System Overview Tool (developed within the Joint Controls Project - JCOP), which provides a centralized interface to the FMC tool and adds PVSS project monitoring and control. The implementation of these tools has provided a reliable and efficient way to manage the system, both during normal operations as well as during shutdowns, upgrades or maintenance operations. This paper will present the particular implementation of this tool in the LHCb experiment and the benefits of its usage in a large scale heterogeneous system

  14. The LHCb magnet design team

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    Photos 01, 02: The LHCb magnet is equipped with resistive coils. Having a "warm " rather than a superconducting magnet, as was originally planned, was a design choice advocated by former Technical Coordinator Hans-Jurgen Hilke. Although this solution was adopted to keep the experiment on budget and on schedule, the geometry required and the need for good lateral homogeneity of the magnetic field called for an innovative design, developed by Wilfried Flegel. Jacques André, Claude Rosset and Olivier Jamet were responsible for the working drawings while Marcello Losasso did the 3-D calculations of the magnetic field. The LHCb magnet design team is pictured in front of one of the two magnet coils which recently arrived at CERN. Each coil comprises 15 individual monolayer ´pancakes´ of identical trapezoidal racetrack shape, and is bent at 45 degrees on the two transverse sides. Each pancake consists of 15 turns of conductor, wound from a 300-m length of extruded aluminium. Left to right: Olivier Jamet, Hans-Jur...

  15. Implications of LHCb measurements and future prospects

    CERN Multimedia

    Ordan, Julien Marius

    2017-01-01

    This is the 2017 edition of a series of workshops between the LHCb collaboration and the theory community. It follows similar meetings held on 10-11 Nov. 2011, 16-18 April 2012 (which resulted in a paper published in EPJ C 73 (2013) 2373), 14-16 Oct. 2013, 15-17 Oct. 2014, 3-5 Nov. 2015 and 12-14 Oct. 2016. The purpose of the meeting is to consider the latest results from LHCb, discuss possible interpretations and identify important channels and observables to test leading theoretical frameworks in the near future of LHCb data-taking.

  16. Data acquisition system for LHCb calorimeter

    International Nuclear Information System (INIS)

    Dai Gang; Gong Guanghua; Shao Beibei

    2007-01-01

    LHCb Calorimeter system is mainly used to identify and measure the energy of the photon, electron, hadron produced by the collision of proton. TELL1 is a common data acquisition platform based on FPGA for LHCb experiment. It is used to adopt custom data acquisition and process method for every detector and provide the data standard for the CPU matrix. This paper provides a novel DAQ and data process model in VHDL for Calorimeter. According to this model. We have built an effective Calorimeter DAQ system, which would be used in LHCb Experiment. (authors)

  17. LHCb: The Evolution of the LHCb Grid Computing Model

    CERN Multimedia

    Arrabito, L; Bouvet, D; Cattaneo, M; Charpentier, P; Clarke, P; Closier, J; Franchini, P; Graciani, R; Lanciotti, E; Mendez, V; Perazzini, S; Nandkumar, R; Remenska, D; Roiser, S; Romanovskiy, V; Santinelli, R; Stagni, F; Tsaregorodtsev, A; Ubeda Garcia, M; Vedaee, A; Zhelezov, A

    2012-01-01

    The increase of luminosity in the LHC during its second year of operation (2011) was achieved by delivering more protons per bunch and increasing the number of bunches. Taking advantage of these changed conditions, LHCb ran with a higher pileup as well as a much larger charm physics introducing a bigger event size and processing times. These changes led to shortages in the offline distributed data processing resources, an increased need of cpu capacity by a factor 2 for reconstruction, higher storage needs at T1 sites by 70\\% and subsequently problems with data throughput for file access from the storage elements. To accommodate these changes the online running conditions and the Computing Model for offline data processing had to be adapted accordingly. This paper describes the changes implemented for the offline data processing on the Grid, relaxing the Monarc model in a first step and going beyond it subsequently. It further describes other operational issues discovered and solved during 2011, present the ...

  18. LHCb: Radiation hard programmable delay line for LHCb Calorimeter Upgrade

    CERN Multimedia

    Mauricio Ferre, J; Vilasís Cardona, X; Picatoste Olloqui, E; Machefert, F; Lefrançois, J; Duarte, O

    2013-01-01

    This poster describes the implementation of a SPI-programmable clock delay chip based on a Delay Locked Loop (DLL) in order to shift the phase of the LHC clock (25 ns) in steps of 1ns, with a 4ps jitter and 18ps of DNL. The delay lines will be integrated into ICECAL, the LHCb calorimeter front-end ASIC in the near future. The stringent noise requirements on the ASIC imply minimizing the noise contribution of digital components. This is accomplished by implementing the DLL in differential mode. To achieve the required radiation tolerance several techniques are applied: double guard rings between PMOS and NMOS transistors as well as glitch suppressors and TMR Registers. This 5.7 mm2 chip has been implemented in CMOS 0.35um technology.

  19. LHCb: Handling online information in the LHCb experiment

    CERN Multimedia

    Barandela Pazos, M D C

    2009-01-01

    The LHCb experiment is a complex particle physics detector, large amount of information is needed for its run time configuration, control and monitoring. All these data are stored in the three main logical databases of the online system: configuration database, archiving database and conditions database. The configuration database contains information needed by the online hardware and software components, like for example the electronics boards, high voltage and low voltage power supplies and trigger algorithms, to be configured, according to the partitioning mode (which components are needed) and running mode(which data are being produced: physics, cosmic, test, etc.). The archiving database contains all data read from hardware used for the monitoring and debugging of the experiment, like for example temperature readings. The third online database, the conditions database, contains a subset of the monitoring data, read from hardware, that are needed for physics processing and also some configuration data...

  20. LHCb - Search for hidden-sector bosons at LHCb

    CERN Multimedia

    Mauri, Andrea

    2016-01-01

    A search is presented for a hidden-sector boson, $\\chi$, produced in the decay $B^0 \\rightarrow K^* (892)^0 \\chi$, with $K^* (892)^0 \\rightarrow K^+ \\pi^-$ and $\\chi \\rightarrow \\mu^+ \\mu^-$ . The search is performed using a $pp$-collision data sample collected at $\\sqrt{s}=7$ and 8 TeV with the LHCb detector, corresponding to integrated luminosities of 1 and 2 fb$^{-1}$ respectively. No significant signal is observed in the mass range $214 \\le m_\\chi \\le 4350$ MeV, and upper limits are placed on the branching fraction product $\\mathcal{B}(B^0 \\rightarrow K^* (892)^0 \\chi) \\times \\mathcal{B}(\\chi \\rightarrow \\mu^+ \\mu^- )$ as a function of the mass and lifetime of the $\\chi$ boson. These limits place the most stringent constraints to date on many theories that predict the existence of additional low-mass dark bosons.

  1. LHCb: Radiative decays of B hadrons at LHCb

    CERN Multimedia

    Soomro, F

    2009-01-01

    Flavour physics is an excellent probe of physics beyond the Standard Model. It offers the possibility to measure effects from heavy virtual particles with masses above the experimental reach in terms of direct production. LHCb is well positioned to exploit the large statistics of B hadrons available at LHC, to make competitive measurements in various radiative decays like B_d->K^{*} , B_s\\phi\\gamma, \\Lambda_b->\\Lambda ^{0\\gamma} and B^+->\\phiK^{+\\gamma}.. For example, the direct CP asymmetry in K^{*\\gamma} decay can be measured to the level of 1.8%[1], better than the current experimental accuracy, with only 100 pb-1of integrated luminosity.

  2. Upgrade of the LHCb ECAL monitoring system

    CERN Document Server

    Guz, Yu

    2015-01-01

    The LHCb ECAL is a shashlik calorimeter of 6016 cells, covering 7.68 x 6.24 m$^2$ area. To monitor the readout chain of each ECAL cell, the LHCb ECAL is equipped with a LED based monitoring system. During the LHC Run I (2009-2012) it was found that the precision of the monitoring suffers from the radiation degradation of transparency of polystyrene clear fibers used to transport the LED light to the ECAL photomultipliers. In order to improve the performance of the monitoring system, and especially in view of significant increase of LHCb working luminosity foreseen after 2018, the present plastic fibers have been replaced by radiation hard quartzfi bers. The performance of the old LHCb ECAL monitoring system during LHC Run I and the design of the upgraded system are discussed here.

  3. Synergy of BESIII and LHCb physics programmes

    CERN Document Server

    Malde, Sneha Sirirshkumar

    2016-01-01

    There is potential for BESIII open-charm measurements to have a significant impact on the LHCb physics programme. Despite the general purpose design of the LHCb detector there are certain inputs that can be better determined in other environments or in production mechanisms not accessible at the LHC. With the unprecedented amount of LHCb data that will become available over the one-to-two decades it is necessary to consider where additional inputs are essential, to avoid the situation where the uncertainty on a measurement is dominated by the lack of knowledge of an external input. This document considers the capabilities of the BESIII experiment to provide vital inputs into key LHCb measurements. A number of different potential measurements that could be pursued are discussed.

  4. The LHCb Silicon Tracker, first operational results

    CERN Document Server

    Esperante, D; Adeva, B; Gallas, A; Pérez Trigo, E; Rodríguez Pérez, P; Pazos Álvarez, A; Saborido, J; Vàzquez, P; Bay, A; Bettler, M O; Blanc, F; Bressieux, J; Conti, G; Dupertuis, F; Fave, V; Frei, R; Gauvin, N; Haefeli, G; Keune, A; Luisier, J; Muresan, R; Nakada, T; Needham, M; Nicolas, L; Knecht, M; Potterat, C; Schneider, O; Tran, M; Aquines Gutierrez, O; Bauer, C; Britsch, M; Hofmann, W; Maciuc, F; Schmelling, M; Voss, H; Anderson, J; Buechler, A; Bursche, A; Chiapolini, N; de Cian, M; Elsaesser, C; Hangartner, V; Salzmann, C; Steiner, S; Steinkamp, O; Straumann, U; van Tilburg, J; Tobin, M; Vollhardt, A; Iakovenko, V; Okhrimenko, O; Pugatch, V

    2010-01-01

    The Large Hadron Collider beauty (LHCb) experiment at CERN (Conseil Européen pour la Recherche Nucléaire) is designed to perform precision measurements of b quark decays. The LHCb Silicon Tracker consists of two sub-detectors, the Tracker Turicensis and the Inner Tracker, which are built from silicon micro-strip technology. First performance results of both detectors using data from Large Hadron Collider synchronization tests are presented.

  5. Considerations on Xi- reconstruction in LHCb

    CERN Document Server

    Brochu, F.M.

    2016-01-01

    This paper describes an alternative method of charged hyperon reconstruction applicable to the LHCb experiment. It extends the seminal work of the FOCUS collaboration to the specific detector layout of LHCb and addresses the reconstruction ambiguities reported in their earlier work, leading to improvements in the reconstruction efficiency for the specific cases of Xi- and Omega- baryon decays to a charged meson and a Lambda baryon.

  6. Heavy Flavour and Quarkonia production at LHCb

    Science.gov (United States)

    Müller, Katharina; LHCb Collaboration

    2017-07-01

    The LHCb detector, with its excellent momentum resolution and flexible trigger strategy, is ideally suited for measuring heavy quark and quarkonia production properties. Recent LHCb measurements of inclusive and differential cross-sections of the production of J/ψ and ϒ resonances, as well as charm, bottom and top quarks, in pp collisions at different centre-of-mass energies are presented. Finally, results on the associated production of ϒ and open charm hadrons and the exclusive production of charmonium are discussed.

  7. Heavy Flavour and Quarkonia production at LHCb

    CERN Document Server

    AUTHOR|(CDS)2080005

    2017-01-01

    The LHCb detector, with its excellent momentum resolution and flexible trigger strategy, is ideally suited for measuring heavy quark and quarkonia production properties. Recent LHCb measurements of inclusive and differential cross-sections of the production of $J/\\psi= $ and $\\Upsilon$ resonances, as well as charm, bottom and top quarks, in $pp$ collisions at different centre-of-mass energies are presented. Finally, results on the associated production of $\\Upsilon$ and open charm hadrons and the exclusive production of charmonium are discussed.

  8. The upgrade of the LHCb trigger system

    CERN Document Server

    INSPIRE-00259834; Fitzpatrick, C.; Gligorov, V.; Raven, G.

    2014-10-20

    The LHCb experiment will operate at a luminosity of $2\\times10^{33}$ cm$^{-2}$s$^{-1}$ during LHC Run 3. At this rate the present readout and hardware Level-0 trigger become a limitation, especially for fully hadronic final states. In order to maintain a high signal efficiency the upgraded LHCb detector will deploy two novel concepts: a triggerless readout and a full software trigger.

  9. LHCbDIRAC as Apache Mesos microservices

    Science.gov (United States)

    Haen, Christophe; Couturier, Benjamin

    2017-10-01

    The LHCb experiment relies on LHCbDIRAC, an extension of DIRAC, to drive its offline computing. This middleware provides a development framework and a complete set of components for building distributed computing systems. These components are currently installed and run on virtual machines (VM) or bare metal hardware. Due to the increased workload, high availability is becoming more and more important for the LHCbDIRAC services, and the current installation model is showing its limitations. Apache Mesos is a cluster manager which aims at abstracting heterogeneous physical resources on which various tasks can be distributed thanks to so called “frameworks” The Marathon framework is suitable for long running tasks such as the DIRAC services, while the Chronos framework meets the needs of cron-like tasks like the DIRAC agents. A combination of the service discovery tool Consul together with HAProxy allows to expose the running containers to the outside world while hiding their dynamic placements. Such an architecture brings a greater flexibility in the deployment of LHCbDirac services, allowing for easier deployment maintenance and scaling of services on demand (e..g LHCbDirac relies on 138 services and 116 agents). Higher reliability is also easier, as clustering is part of the toolset, which allows constraints on the location of the services. This paper describes the investigations carried out to package the LHCbDIRAC and DIRAC components into Docker containers and orchestrate them using the previously described set of tools.

  10. LHCb Online event processing and filtering

    Science.gov (United States)

    Alessio, F.; Barandela, C.; Brarda, L.; Frank, M.; Franek, B.; Galli, D.; Gaspar, C.; Herwijnen, E. v.; Jacobsson, R.; Jost, B.; Köstner, S.; Moine, G.; Neufeld, N.; Somogyi, P.; Stoica, R.; Suman, S.

    2008-07-01

    The first level trigger of LHCb accepts one million events per second. After preprocessing in custom FPGA-based boards these events are distributed to a large farm of PC-servers using a high-speed Gigabit Ethernet network. Synchronisation and event management is achieved by the Timing and Trigger system of LHCb. Due to the complex nature of the selection of B-events, which are the main interest of LHCb, a full event-readout is required. Event processing on the servers is parallelised on an event basis. The reduction factor is typically 1/500. The remaining events are forwarded to a formatting layer, where the raw data files are formed and temporarily stored. A small part of the events is also forwarded to a dedicated farm for calibration and monitoring. The files are subsequently shipped to the CERN Tier0 facility for permanent storage and from there to the various Tier1 sites for reconstruction. In parallel files are used by various monitoring and calibration processes running within the LHCb Online system. The entire data-flow is controlled and configured by means of a SCADA system and several databases. After an overview of the LHCb data acquisition and its design principles this paper will emphasize the LHCb event filter system, which is now implemented using the final hardware and will be ready for data-taking for the LHC startup. Control, configuration and security aspects will also be discussed.

  11. LHCb Online event processing and filtering

    International Nuclear Information System (INIS)

    Alessio, F; Barandela, C; Brarda, L; Frank, M; Gaspar, C; Herwijnen, E v; Jacobsson, R; Jost, B; Koestner, S; Moine, G; Neufeld, N; Somogyi, P; Stoica, R; Suman, S; Franek, B; Galli, D

    2008-01-01

    The first level trigger of LHCb accepts one million events per second. After preprocessing in custom FPGA-based boards these events are distributed to a large farm of PC-servers using a high-speed Gigabit Ethernet network. Synchronisation and event management is achieved by the Timing and Trigger system of LHCb. Due to the complex nature of the selection of B-events, which are the main interest of LHCb, a full event-readout is required. Event processing on the servers is parallelised on an event basis. The reduction factor is typically 1/500. The remaining events are forwarded to a formatting layer, where the raw data files are formed and temporarily stored. A small part of the events is also forwarded to a dedicated farm for calibration and monitoring. The files are subsequently shipped to the CERN Tier0 facility for permanent storage and from there to the various Tier1 sites for reconstruction. In parallel files are used by various monitoring and calibration processes running within the LHCb Online system. The entire data-flow is controlled and configured by means of a SCADA system and several databases. After an overview of the LHCb data acquisition and its design principles this paper will emphasize the LHCb event filter system, which is now implemented using the final hardware and will be ready for data-taking for the LHC startup. Control, configuration and security aspects will also be discussed

  12. DIRAC: reliable data management for LHCb

    International Nuclear Information System (INIS)

    Smith, A C; Tsaregorodtsev, A

    2008-01-01

    DIRAC, LHCb's Grid Workload and Data Management System, utilizes WLCG resources and middleware components to perform distributed computing tasks satisfying LHCb's Computing Model. The Data Management System (DMS) handles data transfer and data access within LHCb. Its scope ranges from the output of the LHCb Online system to Grid-enabled storage for all data types. It supports metadata for these files in replica and bookkeeping catalogues, allowing dataset selection and localization. The DMS controls the movement of files in a redundant fashion whilst providing utilities for accessing all metadata. To do these tasks effectively the DMS requires complete self integrity between its components and external physical storage. The DMS provides highly redundant management of all LHCb data to leverage available storage resources and to manage transient errors in underlying services. It provides data driven and reliable distribution of files as well as reliable job output upload, utilizing VO Boxes at LHCb Tier1 sites to prevent data loss. This paper presents several examples of mechanisms implemented in the DMS to increase reliability, availability and integrity, highlighting successful design choices and limitations discovered

  13. LS1 Report: LHCb's early Christmas

    CERN Multimedia

    Katarina Anthony

    2014-01-01

    Accelerator chain up and running... CCC Operators back at their desks... all telltale signs of the start of Run 2! For the experiments, that means there are just a few short weeks left for them to prepare for beams. Over at LHCb, teams have kept ahead of the curve by focusing on new installations and improvements.   A delicate task: re-connecting the beam pipe in LHCb. From the primary detector services to the DAQ system to the high level trigger, November's injector test beams saw their way through a well-prepared LHCb experiment. “We set the transfer line tests as our deadline for the restart - the entire experiment had to be at nominal position and conditions,” says Eric Thomas, LHCb deputy Technical Coordinator and LHCb LS1 Project Coordinator. “Achieving this was a major milestone for the collaboration. If beam were to come tomorrow, we would be ready.” The injector tests gave the LHCb team a chance to synchronise their detectors, and to al...

  14. User analysis of LHCb data with Ganga

    International Nuclear Information System (INIS)

    Maier, Andrew; Gaidioz, Benjamin; Moscicki, Jakub; Muraru, Adrian; Ster, Daniel van der; Brochu, Frederic; Cowan, Greg; Egede, Ulrik; Reece, Will; Williams, Mike; Elmsheuser, Johannes; Harrison, Karl; Slater, Mark; Tan, Chun Lik; Lee, Hurng-Chun; Liko, Dietrich; Pajchel, Katarina; Samset, Bjoern; Soroko, Alexander

    2010-01-01

    GANGA (http://cern.ch/ganga) is a job-management tool that offers a simple, efficient and consistent user analysis tool in a variety of heterogeneous environments: from local clusters to global Grid systems. Experiment specific plug-ins allow GANGA to be customised for each experiment. For LHCb users GANGA is the officially supported and advertised tool for job submission to the Grid. The LHCb specific plug-ins allow support for end-to-end analysis helping the user to perform his complete analysis with the help of GANGA. This starts with the support for data selection, where a user can select data sets from the LHCb Bookkeeping system. Next comes the set up for large analysis jobs: with tailored plug-ins for the LHCb core software, jobs can be managed by the splitting of these analysis jobs with the subsequent merging of the resulting files. Furthermore, GANGA offers support for Toy Monte-Carlos to help the user tune their analysis. In addition to describing the GANGA architecture, typical usage patterns within LHCb and experience with the updated LHCb DIRAC workload management system are presented.

  15. Bs semileptonic asymmetry at LHCb

    CERN Multimedia

    Dufour, Laurent

    2016-01-01

    When neutral $B^{0}_{s,d}$ mesons evolve in time they can change into their own antiparticles. In this mixing process CP symmetry is not necessarily conserved, as the probability for a $B^{0}$ meson to change into a $\\bar{B}^{0}$ meson can be different from the probability for the reverse process. The CP violation in the $B^{0}_{s}$ system as measured using semileptonic decays, defined as $a^{s}_{sl}$, is very small according to the Standard Model. However, earlier measurements of the semileptonic mixing asymmetry in both the $B_s^{0}$ and $B_d^{0}$ systems have shown a $3 \\sigma$ deviation with respect to the Standard Model value. A measurement of $a^{s}_{sl}$ performed using $1 \\text{fb}^{-1}$ of data collected at the LHCb detector is presented, together with an outlook to the updated $3 \\text{fb}^{-1}$ result.

  16. The LHCb Silicon Tracker Project

    International Nuclear Information System (INIS)

    Agari, M.; Bauer, C.; Baumeister, D.; Blouw, J.; Hofmann, W.; Knoepfle, K.T.; Loechner, S.; Schmelling, M.; Pugatch, V.; Bay, A.; Carron, B.; Frei, R.; Jiminez-Otero, S.; Tran, M.-T.; Voss, H.; Adeva, B.; Esperante, D.; Lois, C.; Vasquez, P.; Bernhard, R.P.; Bernet, R.; Ermoline, Y.; Gassner, J.; Koestner, S.; Lehner, F.; Needham, M.; Siegler, M.; Steinkamp, O.; Straumann, U.; Vollhardt, A.; Volyanskyy, D.

    2006-01-01

    Two silicon strip detectors, the Trigger Tracker(TT) and the Inner Tracker(Italy) will be constructed for the LHCb experiment. Transverse momentum information extracted from the TT will be used in the Level 1 trigger. The IT is part of the main tracking system behind the magnet. Both silicon detectors will be read out using a custom-developed chip by the ASIC lab in Heidelberg. The signal-over-noise behavior and performance of various geometrical designs of the silicon sensors, in conjunction with the Beetle read-out chip, have been extensively studied in test beam experiments. Results from those experiments are presented, and have been used in the final choice of sensor geometry

  17. Search for Exotics with LHCb

    CERN Multimedia

    Muster, Bastien

    2015-01-01

    A search is presented for long-lived particles with a mass between 25 and 50 GeV/c^2 and a lifetime between 1 and 200ps in a sample of proton-proton collisions at a centre-of-mass energy of \\sqrt{s} = 7TeV, corresponding to an integrated luminosity of 0.62fb^{-1}, collected by the LHCb detector. The particles are assumed to be pair-produced by the decay of a Standard Model-like Higgs boson. The experimental signature of the long-lived particle is a displaced vertex with two associated jets. No excess above the background is observed and limits are set on the production cross-section as a function of the long-lived particle mass and lifetime.

  18. LHCb: Measurement of polarisation amplitudes and triple product asymmetries in the $B_s \\to \\phi \\phi$ decay at LHCb

    CERN Multimedia

    Benson, Sean

    2012-01-01

    An untagged, time-integrated analysis of the $B_s \\to \\phi \\phi$ decay has been performed with 1 fb$^{-1}$ of pp collision data at centre-of-mass energy $\\sqrt{s} = 7$ TeV taken using the LHCb detector. Optimised selections have yielded 801 $B_s \\to \\phi \\phi$ events at high signal to background ratio. This has allowed for measurements of polarisation amplitudes ($|A_0|^2$, $|A_\\perp|^2$, $|A_\\parallel|^2$) and strong phase difference (cos$\\delta_\\parallel$) to be performed. T-violating triple product asymmetries have yielded results $A_U=-0.055 \\pm 0.036\\mathrm{(stat.)} \\pm 0.018\\mathrm{(syst.)}$ and $A_V = 0.010 \\pm 0.036\\mathrm{(stat.)} \\pm 0.018\\mathrm{(syst.)}$.

  19. Observation of Au + AuAu + Au + ρ0 and Au + AuAu* + Au* + ρ0 with STAR

    International Nuclear Information System (INIS)

    Spencer, K.

    2002-01-01

    First observation of the reactions Au + AuAu + Au + ρ 0 and Au + AuAu* + Au* + ρ 0 with the STAR detector are reported. The ρ are produced at small perpendicular momentum, as expected if they couple coherently to both nuclei. Models of vector meson production and the correlation with nuclear breakup are discussed, as well as a fundamental test of quantum mechanics that is possible with the system. (author)

  20. LHCb: Fast Readout Control for the upgraded readout architecture of the LHCb experiment at CERN

    CERN Multimedia

    Alessio, F

    2013-01-01

    The LHCb experiment at CERN has proposed an upgrade towards a full 40 MHz readout system in order to run between five and ten times its initial design luminosity with an upgraded LHCb detector. As a consequence, the various LHCb sub-systems in the readout architecture will be upgraded to cope with higher sub-detector occupancies, higher rate, and higher readout load. The new architecture, new functionalities, and the first hardware implementation of a new LHCb Readout Control system (commonly referred to as S-TFC) for the upgraded LHCb experiment is here presented. Our attention is focused in describing solutions for the distribution of clock and timing information to control the entire upgraded readout architecture by profiting of a bidirectional optical network and powerful FPGAs, including a real-time mechanism to synchronize the entire system. Solutions and implementations are presented, together with first results on the simulation and the validation of the system.

  1. LHCb Computing Resources: 2019 requests and reassessment of 2018 requests

    CERN Document Server

    Bozzi, Concezio

    2017-01-01

    This document presents the computing resources needed by LHCb in 2019 and a reassessment of the 2018 requests, as resulting from the current experience of Run2 data taking and minor changes in the LHCb computing model parameters.

  2. Reconstruction and calibration strategies for the LHCb RICH detector

    CERN Multimedia

    2006-01-01

    - LHCb particle identification - LHCb ring pattern recognition algorithm requirements - RICH pattern recognition - Cherenkov angle reconstruction online - Online PID - Hough transform - Metropolis- Hastings Markov chains - PID online: physics performances - Rich PID Callibration

  3. Production and test of the LHCb Muon Chamber

    CERN Multimedia

    2005-01-01

    - The Muon System of LHCb - The Multi-Wire Proportional Chambers for LHCb - Wire tension meter - Wire pitch measurement - Gas leakage test - Test with cosmic rays - Production and test summary - Gap gain uniformity - Production and test summary

  4. Mesure des champs de radiation dans le detecteur ATLAS et sa caverne avec les detecteurs au silicium a pixels ATLAS-MPX

    Science.gov (United States)

    Bouchami, Jihene

    The LHC proton-proton collisions create a hard radiation environment in the ATLAS detector. In order to quantify the effects of this environment on the detector performance and human safety, several Monte Carlo simulations have been performed. However, direct measurement is indispensable to monitor radiation levels in ATLAS and also to verify the simulation predictions. For this purpose, sixteen ATLAS-MPX devices have been installed at various positions in the ATLAS experimental and technical areas. They are composed of a pixelated silicon detector called MPX whose active surface is partially covered with converter layers for the detection of thermal, slow and fast neutrons. The ATLAS-MPX devices perform real-time measurement of radiation fields by recording the detected particle tracks as raster images. The analysis of the acquired images allows the identification of the detected particle types by the shapes of their tracks. For this aim, a pattern recognition software called MAFalda has been conceived. Since the tracks of strongly ionizing particles are influenced by charge sharing between adjacent pixels, a semi-empirical model describing this effect has been developed. Using this model, the energy of strongly ionizing particles can be estimated from the size of their tracks. The converter layers covering each ATLAS-MPX device form six different regions. The efficiency of each region to detect thermal, slow and fast neutrons has been determined by calibration measurements with known sources. The study of the ATLAS-MPX devices response to the radiation produced by proton-proton collisions at a center of mass energy of 7 TeV has demonstrated that the number of recorded tracks is proportional to the LHC luminosity. This result allows the ATLAS-MPX devices to be employed as luminosity monitors. To perform an absolute luminosity measurement and calibration with these devices, the van der Meer method based on the LHC beam parameters has been proposed. Since the ATLAS-MPX devices response and the luminosity are correlated, the results of measuring radiation levels are expressed in terms of particle fluences per unit integrated luminosity. A significant deviation has been obtained when comparing these fluences with those predicted by GCALOR, which is one of the ATLAS detector simulations. In addition, radiation measurements performed at the end of proton-proton collisions have demonstrated that the decay of radionuclides produced during collisions can be observed with the ATLAS-MPX devices. The residual activation of ATLAS components can be measured with these devices by means of ambient dose equivalent calibration. Keywords: pattern recognition, charge sharing effect, neutron detection efficiency, luminosity, van der Meer method, particle fluences, GCALOR simulation, residual activation, ambient dose equivalent.

  5. Study of problems arising from the use of thermal neutron detectors in a pulsed regime. Application to the development of a digital transferometer adapted to receive signals from these detectors; Etude des problemes poses par l'utilisation des detecteurs de neutrons thermiques fonctionnant en regime impulsionnel. Application a la realisation d'un transferometre numerique adapte aux signaux fournis par ces detecteurs

    Energy Technology Data Exchange (ETDEWEB)

    Le Tilly, Y [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1966-12-01

    The instantaneous value of the counting rate of the pulses given by a fission detector settled in a reactor follows the neutron flux, but it is shown that the counter adds a white noise to the measured signal. This report deals with some possibilities of on line numerical handling afforded by this kind of signals. One considers first the influence of a by N numerical divider and one shows that, acting like a quantifier, it adds to the signal a white noise with the power N{sup 2}/{sub 12}. One, studies afterwards the principle of a digital filter aimed to Fourier analyse the signal. The realization of this device is described. It can be used in transfer function measurements at frequencies below 125 kHz. Some examples of experiments performed with this apparatus are presented. One discusses finally the design, according to the same principle, of a power spectral density analyser in the frequency range 0,01 - 10 000 Hz for random signal of the same kind. (author) [French] La valeur instantanee de la frequence de recurrence des impulsions issues d'un detecteur a fission place dans un reacteur est proportionnelle au flux neutronique. Apres avoir montre que le detecteur ajoute un bruit blanc au signal mesure, on etudie clans ce rapport certaines possibilites de traitement numerique en temps reel offertes par ce type de signaux. On examine d'abord l'influence d'un diviseur numerique par N, et l'on montre que son action, semblable a une quantification, ajoute au signal un bruit blanc de puissance N{sup 2}/{sub 12}. On, etudie ensuite le principe d'un filtre numerique destine a effectuer l'analyse de Fourier du signal, et l'on decrit la realisation de cet appareil qui peut etre utilise pour mesurer des fonctions de transfert a une frequence quelconque inferieure a 10 kHz. Des exemples de mesures faites avec cet appareil sont presentes. On discute enfin la possibilite de realiser suivant le meme principe un analyseur de densite spectrale dans la bande de frequence 0,01 Hz

  6. LHCb: The LHCb Muon detector commissioning and first running scenarios

    CERN Multimedia

    Furcas, S

    2009-01-01

    The LHCb Muon detector, being part of the first trigger level (L0), has been optimized in order to provide a fast and efficient identification of the muons produced in pp collisions at the LHC. The expected performances are: 95% L0 trigger efficiency within a 25ns time window and muon identification in L0 with a pT resolution of ~20%. The detector has been built, to met those stringent requirements, using Multi Wire Proportional Chambers and Gas Electron Multiplier (in the innermost region, closest to the IP) technology. The chambers (1368 MWPC + 12 GEM) are arranged in 5 detector stations, interspersed with iron filters placed along the beam pipe. While the installation of chambers in stations 2 to 5 has already been completed, the work on the first and most challenging station is still ongoing and expected to end by July 09. The results obtained in the commissioning of all the installed chambers as well as the performances measured by means of data acquired during cosmics runs since September 08 are reviewe...

  7. LHCb : A Scintillating Fibre Trackind Detector for the LHCb Upgrade

    CERN Multimedia

    Lindner, Rolf

    2014-01-01

    LHCb is preparing the upgrade which is scheduled to be installed in 2018/19. The Scintillating Fibre (SciFi) Tracker will be designed to replace the current tracking system downstream of the magnet, required to run at an increased luminosity of 1 - 2 10$^{33}$ cm$^{-2}$s$^{-1}$ and to collect a total of 50fb$^{-1}$ of data. The readout of the detector will be at 40MHz, applying a full software based trigger for every single bunch crossing. The SciFi Tracker consists of 12 planes covering a total surface of 350 m2. Modules are based on 2.5 m long multilayer ribbons made of 250 um diameter scintillating fibres as the active medium and signal transport. Silicon photomultiplier (SiPM) arrays with 128 channels at a width of 250 um are used for the readout. The signals from the SiPMS are digitized on an ASIC chip before reconstructing the track hit position within an FPGA on the front-end board. Several challenges facing this detector and the significant progress over the last year will be presented regarding the p...

  8. LHCb calorimeter electronics. Photon identification. Calorimeter calibration

    International Nuclear Information System (INIS)

    Machefert, F.

    2011-01-01

    LHCb is one of the four large experiments installed on the LHC accelerator ring. The aim of the detector is to precisely measure CP violation observables and rare decays in the B meson sector. The calorimeter system of LHCb is made of four sub-systems: the scintillating pad detector, the pre-shower, the electromagnetic (ECAL) and hadronic (HCAL) calorimeters. It is essential to reconstruct B decays, to efficiently trigger on interesting events and to identify electrons and photons. After a review of the LHCb detector sub-systems, the first part of this document describes the calorimeter electronics. First, the front-end electronics in charge of measuring the ECAL and HCAL signals from the photomultipliers is presented, then the following section is an overview of the control card of the four calorimeters. The chapters three and four concern the test software of this electronics and the technological choices making it tolerant to radiations in the LHCb cavern environment. The measurements performed to ensure this tolerance are also given. The second part of this document concerns both the identification of the photons with LHCb and the calibration of the calorimeters. The photon identification method is presented and the performances given. Finally, the absolute energy calibration of the PRS and ECAL, based on the data stored in 2010 is explained. (author)

  9. Monitoring the LHCb data quality system

    CERN Multimedia

    Baranov, Alexander

    2016-01-01

    Monitoring the quality of the data, DQM, is crucial in a high-energy physics experiment to ensure the correct functioning of the apparatus during the data taking. DQM at LHCb is carried out in two phase. The first one is performed on-site, in real time, using unprocessed data directly from the LHCb detector, while the second, also performed on-site, requires the reconstruction of the data selected by the LHCb trigger system and occurs with some delay. For the Run II data taking the LHCb collaboration has re-engineered the DQM protocols and the DQM graphical interface, moving the latter to a web-based monitoring system, called Monet, thus allowing researchers to perform the second phase off-site. In order to support the operator's task, Monet is also equipped with an automated, fully configurable, alarm system, thus allowing its use not only for DQM purposes, but also to track and assess the quality of LHCb software and simulation.

  10. LHCb: full-steam strategy pays off

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    LHCb looks at LHC proton collisions from a special angle. The experiment studies rare decays of the B particle to look into the physical processes that might hide new physics. Designed to operate at moderate luminosity, LHCb has been more daring for the last year and is running at conditions tougher than the nominal. The new strategy is paying off, as important physics results have just started to emerge…   Event display presented at the EPS-HEP 2011 conference showing a B0s meson decaying into a μ+ and μ- pair.  The LHCb detector was originally designed to run at moderate luminosity and low interaction pile-up. In other words, unlike the CMS and ATLAS experiments, the whole LHCb experimental set-up and data-taking infrastructure was designed to process just one proton interaction for each bunch crossing. For the last year, however, this has all been old news. A change in LHCb strategy was made possible when it became clear that the LHC was going to first i...

  11. Direct search for Higgs boson in LHCb

    CERN Document Server

    Currat, C

    2001-01-01

    The LHCb detector is a forward one-arm spectrometer to precision measurements of CP violation in the B-meson systems. The motivation of the present work is to assess the potential of LHCb to observe a Standard Model (SM) Higgs signal. The recent results obtained at LEP give a hint of a SM Higgs boson with a mass mH = 115.0 +1.3 –0.9 GeV/c2 with a statistical significance of 2.9 standard deviations. Because of the high longitudinal boost encountered by the products in the pp collisions at LHC, a significant fraction (~30%) of light Higgs (mH = 115 GeV/c2) are produced in the LHCb acceptance 1.8 < h < 4.9. These facts potentially place LHCb in the race for the observation of the SM Higgs. Given a relatively low running luminosity of 2 x 1032 cm-2s-1- compared to the nominal 1034 cm-2s-1 at LHC and a limited geometrical acceptance, we have shown that the channels accessible to LHCb are H + W± Z0 b`b + l± X for Higgs masses in the range 100-130 GeV/c2. This work pioneered a setup for the pro...

  12. $CPT$ violation searches and prospects for LHCb

    CERN Document Server

    van Tilburg, Jeroen

    2015-03-06

    An overview of current experimental bounds on $CPT$ violation in neutral meson mixing is given. New values for the $CPT$ asymmetry in the $B^0$ and $B_s^0$ systems are deduced from BaBar, Belle and LHCb data. With dedicated analyses, LHCb will be able to further improve the bounds on $CPT$ violation in the $D^0$, $B^0$ and $B_s^0$ systems. Since $CPT$ violation implies violation of Lorentz invariance, the observed $CPT$ asymmetry will exhibit sidereal- and boost-dependent variations. Such $CPT$-violating and Lorentz-violating effects are accommodated in the framework of the Standard-Model Extension (SME). The large boost of the neutral mesons produced at LHCb results in a high sensitivity to the corresponding SME coefficients. For the $B^0$ and $B_s^0$ systems, using existing LHCb data, we determine with high precision the SME coefficients that are not varying with sidereal time. With a full sidereal analysis, LHCb will be able to improve the existing SME bounds in the $D^0$, $B^0$ and $B_s^0$ systems by up t...

  13. Precision luminosity measurements at LHCb

    CERN Document Server

    Aaij, Roel; Adinolfi, Marco; Affolder, Anthony; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Anderson, Jonathan; Andreassen, Rolf; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Aquines Gutierrez, Osvaldo; Archilli, Flavio; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Batozskaya, Varvara; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Belogurov, Sergey; Belous, Konstantin; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bien, Alexander; Bifani, Simone; Bird, Thomas; Bizzeti, Andrea; Bjørnstad, Pål Marius; Blake, Thomas; Blanc, Frédéric; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borghi, Silvia; Borgia, Alessandra; Borsato, Martino; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Brambach, Tobias; Bressieux, Joël; Brett, David; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Brook, Nicholas; Brown, Henry; Bursche, Albert; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Campana, Pierluigi; Campora Perez, Daniel; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu-Faye; Chiapolini, Nicola; Chrzaszcz, Marcin; Ciba, Krzystof; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coco, Victor; Cogan, Julien; Cogneras, Eric; Cojocariu, Lucian; Collazuol, Gianmaria; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombes, Matthew; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Counts, Ian; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Dalseno, Jeremy; David, Pascal; David, Pieter; Davis, Adam; De Bruyn, Kristof; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Silva, Weeraddana; De Simone, Patrizia; Dean, Cameron Thomas; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Déléage, Nicolas; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Di Canto, Angelo; Dijkstra, Hans; Donleavy, Stephanie; Dordei, Francesca; Dorigo, Mirco; Dosil Suárez, Alvaro; Dossett, David; Dovbnya, Anatoliy; Dreimanis, Karlis; Dujany, Giulio; Dupertuis, Frederic; Durante, Paolo; Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; Easo, Sajan; Egede, Ulrik; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; El Rifai, Ibrahim; Elsasser, Christian; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Färber, Christian; Farinelli, Chiara; Farley, Nathanael; Farry, Stephen; Fay, Robert; Ferguson, Dianne; Fernandez Albor, Victor; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fiore, Marco; Fiorini, Massimiliano; Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fol, Philip; Fontana, Marianna; Fontanelli, Flavio; Forty, Roger; Francisco, Oscar; Frank, Markus; Frei, Christoph; Frosini, Maddalena; Fu, Jinlin; Furfaro, Emiliano; Gallas Torreira, Abraham; Galli, Domenico; Gallorini, Stefano; Gambetta, Silvia; Gandelman, Miriam; Gandini, Paolo; Gao, Yuanning; García Pardiñas, Julián; Garofoli, Justin; Garra Tico, Jordi; Garrido, Lluis; Gascon, David; Gaspar, Clara; Gauld, Rhorry; Gavardi, Laura; Geraci, Angelo; Gersabeck, Evelina; Gersabeck, Marco; Gershon, Timothy; Ghez, Philippe; Gianelle, Alessio; Gianì, Sebastiana; Gibson, Valerie; Giubega, Lavinia-Helena; Gligorov, V.V.; Göbel, Carla; Golubkov, Dmitry; Golutvin, Andrey; Gomes, Alvaro; Gotti, Claudio; Grabalosa Gándara, Marc; Graciani Diaz, Ricardo; Granado Cardoso, Luis Alberto; Graugés, Eugeni; Graziani, Giacomo; Grecu, Alexandru; Greening, Edward; Gregson, Sam; Griffith, Peter; Grillo, Lucia; Grünberg, Oliver; Gui, Bin; Gushchin, Evgeny; Guz, Yury; Gys, Thierry; Hadjivasiliou, Christos; Haefeli, Guido; Haen, Christophe; Haines, Susan; Hall, Samuel; Hamilton, Brian; Hampson, Thomas; Han, Xiaoxue; Hansmann-Menzemer, Stephanie; Harnew, Neville; Harnew, Samuel; Harrison, Jonathan; He, Jibo; Head, Timothy; Heijne, Veerle; Hennessy, Karol; Henrard, Pierre; Henry, Louis; Hernando Morata, Jose Angel; van Herwijnen, Eric; Heß, Miriam; Hicheur, Adlène; Hill, Donal; Hoballah, Mostafa; Hombach, Christoph; Hulsbergen, Wouter; Hunt, Philip; Hussain, Nazim; Hutchcroft, David; Hynds, Daniel; Idzik, Marek; Ilten, Philip; Jacobsson, Richard; Jaeger, Andreas; Jalocha, Pawel; Jans, Eddy; Jaton, Pierre; Jawahery, Abolhassan; Jing, Fanfan; John, Malcolm; Johnson, Daniel; Jones, Christopher; Joram, Christian; Jost, Beat; Jurik, Nathan; Kandybei, Sergii; Kanso, Walaa; Karacson, Matthias; Karbach, Moritz; Karodia, Sarah; Kelsey, Matthew; Kenyon, Ian; Ketel, Tjeerd; Khanji, Basem; Khurewathanakul, Chitsanu; Klaver, Suzanne; Klimaszewski, Konrad; Kochebina, Olga; Kolpin, Michael; Komarov, Ilya; Koopman, Rose; Koppenburg, Patrick; Korolev, Mikhail; Kozlinskiy, Alexandr; Kravchuk, Leonid; Kreplin, Katharina; Kreps, Michal; Krocker, Georg; Krokovny, Pavel; Kruse, Florian; Kucewicz, Wojciech; Kucharczyk, Marcin; Kudryavtsev, Vasily; Kurek, Krzysztof; Kvaratskheliya, Tengiz; La Thi, Viet Nga; Lacarrere, Daniel; Lafferty, George; Lai, Adriano; Lambert, Dean; Lambert, Robert W; Lanfranchi, Gaia; Langenbruch, Christoph; Langhans, Benedikt; Latham, Thomas; Lazzeroni, Cristina; Le Gac, Renaud; van Leerdam, Jeroen; Lees, Jean-Pierre; Lefèvre, Regis; Leflat, Alexander; Lefrançois, Jacques; Leo, Sabato; Leroy, Olivier; Lesiak, Tadeusz; Leverington, Blake; Li, Yiming; Likhomanenko, Tatiana; Liles, Myfanwy; Lindner, Rolf; Linn, Christian; Lionetto, Federica; Liu, Bo; Lohn, Stefan; Longstaff, Iain; Lopes, Jose; Lopez-March, Neus; Lowdon, Peter; Lu, Haiting; Lucchesi, Donatella; Luo, Haofei; Lupato, Anna; Luppi, Eleonora; Lupton, Oliver; Machefert, Frederic; Machikhiliyan, Irina V; Maciuc, Florin; Maev, Oleg; Malde, Sneha; Malinin, Alexander; Manca, Giulia; Mancinelli, Giampiero; Mapelli, Alessandro; Maratas, Jan; Marchand, Jean François; Marconi, Umberto; Marin Benito, Carla; Marino, Pietro; Märki, Raphael; Marks, Jörg; Martellotti, Giuseppe; Martens, Aurelien; Martín Sánchez, Alexandra; Martinelli, Maurizio; Martinez Santos, Diego; Martinez Vidal, Fernando; Martins Tostes, Danielle; Massafferri, André; Matev, Rosen; Mathe, Zoltan; Matteuzzi, Clara; Maurin, Brice; Mazurov, Alexander; McCann, Michael; McCarthy, James; McNab, Andrew; McNulty, Ronan; McSkelly, Ben; Meadows, Brian; Meier, Frank; Meissner, Marco; Merk, Marcel; Milanes, Diego Alejandro; Minard, Marie-Noelle; Moggi, Niccolò; Molina Rodriguez, Josue; Monteil, Stephane; Morandin, Mauro; Morawski, Piotr; Mordà, Alessandro; Morello, Michael Joseph; Moron, Jakub; Morris, Adam Benjamin; Mountain, Raymond; Muheim, Franz; Müller, Katharina; Mussini, Manuel; Muster, Bastien; Naik, Paras; Nakada, Tatsuya; Nandakumar, Raja; Nasteva, Irina; Needham, Matthew; Neri, Nicola; Neubert, Sebastian; Neufeld, Niko; Neuner, Max; Nguyen, Anh Duc; Nguyen, Thi-Dung; Nguyen-Mau, Chung; Nicol, Michelle; Niess, Valentin; Niet, Ramon; Nikitin, Nikolay; Nikodem, Thomas; Novoselov, Alexey; O'Hanlon, Daniel Patrick; Oblakowska-Mucha, Agnieszka; Obraztsov, Vladimir; Oggero, Serena; Ogilvy, Stephen; Okhrimenko, Oleksandr; Oldeman, Rudolf; Onderwater, Gerco; Orlandea, Marius; Otalora Goicochea, Juan Martin; Owen, Patrick; Oyanguren, Maria Arantza; Pal, Bilas Kanti; Palano, Antimo; Palombo, Fernando; Palutan, Matteo; Panman, Jacob; Papanestis, Antonios; Pappagallo, Marco; Pappalardo, Luciano; Parkes, Christopher; Parkinson, Christopher John; Passaleva, Giovanni; Patel, Girish; Patel, Mitesh; Patrignani, Claudia; Pearce, Alex; Pellegrino, Antonio; Pepe Altarelli, Monica; Perazzini, Stefano; Perret, Pascal; Perrin-Terrin, Mathieu; Pescatore, Luca; Pesen, Erhan; Pessina, Gianluigi; Petridis, Konstantin; Petrolini, Alessandro; Picatoste Olloqui, Eduardo; Pietrzyk, Boleslaw; Pilař, Tomas; Pinci, Davide; Pistone, Alessandro; Playfer, Stephen; Plo Casasus, Maximo; Polci, Francesco; Poluektov, Anton; Polycarpo, Erica; Popov, Alexander; Popov, Dmitry; Popovici, Bogdan; Potterat, Cédric; Price, Eugenia; Price, Joseph David; Prisciandaro, Jessica; Pritchard, Adrian; Prouve, Claire; Pugatch, Valery; Puig Navarro, Albert; Punzi, Giovanni; Qian, Wenbin; Rachwal, Bartolomiej; Rademacker, Jonas; Rakotomiaramanana, Barinjaka; Rama, Matteo; Rangel, Murilo; Raniuk, Iurii; Rauschmayr, Nathalie; Raven, Gerhard; Redi, Federico; Reichert, Stefanie; Reid, Matthew; dos Reis, Alberto; Ricciardi, Stefania; Richards, Sophie; Rihl, Mariana; Rinnert, Kurt; Rives Molina, Vincente; Robbe, Patrick; Rodrigues, Ana Barbara; Rodrigues, Eduardo; Rodriguez Perez, Pablo; Roiser, Stefan; Romanovsky, Vladimir; Romero Vidal, Antonio; Rotondo, Marcello; Rouvinet, Julien; Ruf, Thomas; Ruiz, Hugo; Ruiz Valls, Pablo; Saborido Silva, Juan Jose; Sagidova, Naylya; Sail, Paul; Saitta, Biagio; Salustino Guimaraes, Valdir; Sanchez Mayordomo, Carlos; Sanmartin Sedes, Brais; Santacesaria, Roberta; Santamarina Rios, Cibran; Santovetti, Emanuele; Sarti, Alessio; Satriano, Celestina; Satta, Alessia; Saunders, Daniel Martin; Savrina, Darya; Schiller, Manuel; Schindler, Heinrich; Schlupp, Maximilian; Schmelling, Michael; Schmidt, Burkhard; Schneider, Olivier; Schopper, Andreas; Schubiger, Maxime; Schune, Marie Helene; Schwemmer, Rainer; Sciascia, Barbara; Sciubba, Adalberto; Semennikov, Alexander; Sepp, Indrek; Serra, Nicola; Serrano, Justine; Sestini, Lorenzo; Seyfert, Paul; Shapkin, Mikhail; Shapoval, Illya; Shcheglov, Yury; Shears, Tara; Shekhtman, Lev; Shevchenko, Vladimir; Shires, Alexander; Silva Coutinho, Rafael; Simi, Gabriele; Sirendi, Marek; Skidmore, Nicola; Skwarnicki, Tomasz; Smith, Anthony; Smith, Edmund; Smith, Eluned; Smith, Jackson; Smith, Mark; Snoek, Hella; Sokoloff, Michael; Soler, Paul; Soomro, Fatima; Souza, Daniel; Souza De Paula, Bruno; Spaan, Bernhard; Sparkes, Ailsa; Spradlin, Patrick; Sridharan, Srikanth; Stagni, Federico; Stahl, Marian; Stahl, Sascha; Steinkamp, Olaf; Stenyakin, Oleg; Stevenson, Scott; Stoica, Sabin; Stone, Sheldon; Storaci, Barbara; Stracka, Simone; Straticiuc, Mihai; Straumann, Ulrich; Stroili, Roberto; Subbiah, Vijay Kartik; Sun, Liang; Sutcliffe, William; Swientek, Krzysztof; Swientek, Stefan; Syropoulos, Vasileios; Szczekowski, Marek; Szczypka, Paul; Szumlak, Tomasz; T'Jampens, Stephane; Teklishyn, Maksym; Tellarini, Giulia; Teubert, Frederic; Thomas, Christopher; Thomas, Eric; van Tilburg, Jeroen; Tisserand, Vincent; Tobin, Mark; Tolk, Siim; Tomassetti, Luca; Tonelli, Diego; Topp-Joergensen, Stig; Torr, Nicholas; Tournefier, Edwige; Tourneur, Stephane; Tran, Minh Tâm; Tresch, Marco; Trisovic, Ana; Tsaregorodtsev, Andrei; Tsopelas, Panagiotis; Tuning, Niels; Ubeda Garcia, Mario; Ukleja, Artur; Ustyuzhanin, Andrey; Uwer, Ulrich; Vacca, Claudia; Vagnoni, Vincenzo; Valenti, Giovanni; Vallier, Alexis; Vazquez Gomez, Ricardo; Vazquez Regueiro, Pablo; Vázquez Sierra, Carlos; Vecchi, Stefania; Velthuis, Jaap; Veltri, Michele; Veneziano, Giovanni; Vesterinen, Mika; Viaud, Benoit; Vieira, Daniel; Vieites Diaz, Maria; Vilasis-Cardona, Xavier; Vollhardt, Achim; Volyanskyy, Dmytro; Voong, David; Vorobyev, Alexey; Vorobyev, Vitaly; Voß, Christian; de Vries, Jacco; Waldi, Roland; Wallace, Charlotte; Wallace, Ronan; Walsh, John; Wandernoth, Sebastian; Wang, Jianchun; Ward, David; Watson, Nigel; Websdale, David; Whitehead, Mark; Wicht, Jean; Wiedner, Dirk; Wilkinson, Guy; Williams, Matthew; Williams, Mike; Wilschut, Hans; Wilson, Fergus; Wimberley, Jack; Wishahi, Julian; Wislicki, Wojciech; Witek, Mariusz; Wormser, Guy; Wotton, Stephen; Wright, Simon; Wyllie, Kenneth; Xie, Yuehong; Xing, Zhou; Xu, Zhirui; Yang, Zhenwei; Yuan, Xuhao; Yushchenko, Oleg; Zangoli, Maria; Zavertyaev, Mikhail; Zhang, Liming; Zhang, Wen Chao; Zhang, Yanxi; Zhelezov, Alexey; Zhokhov, Anatoly; Zhong, Liang; Zvyagin, Alexander

    2014-12-05

    Measuring cross-sections at the LHC requires the luminosity to be determined accurately at each centre-of-mass energy $\\sqrt{s}$. In this paper results are reported from the luminosity calibrations carried out at the LHC interaction point 8 with the LHCb detector for $\\sqrt{s}$ = 2.76, 7 and 8 TeV (proton-proton collisions) and for $\\sqrt{s_{NN}}$ = 5 TeV (proton-lead collisions). Both the "van der Meer scan" and "beam-gas imaging" luminosity calibration methods were employed. It is observed that the beam density profile cannot always be described by a function that is factorizable in the two transverse coordinates. The introduction of a two-dimensional description of the beams improves significantly the consistency of the results. For proton-proton interactions at $\\sqrt{s}$ = 8 TeV a relative precision of the luminosity calibration of 1.47% is obtained using van der Meer scans and 1.43% using beam-gas imaging, resulting in a combined precision of 1.12%. Applying the calibration to the full data set determin...

  14. Filling the vacuum at LHCb

    CERN Multimedia

    Katarina Anthony

    2013-01-01

    Last month, the Vacuum, Surfaces and Coatings (VSC) group was tasked with an unusually delicate operation in the LHCb experiment cavern: removing the LHC beam pipe while keeping the sensitive Vertex Locator vacuum vessel (VELO) completely isolated from the action.   The VSC group seal off the VELO beam pipe with a flange. Image: Gloria Corti. LHCb’s VELO detector is one of the crown jewels of the experiment. With detector elements surrounded by a vacuum, it gets as close as 5 cm from the beam. Fantastic for physics, but difficult for all-important access. “Because of the sensitivity of the VELO detector and its proximity to the beam, the collaboration decided not to bake (see box) its portion of the beam pipe,” says Giulia Lanza (TE-VSC-LBV), the expert in charge of the beam vacuum operation. “Our group was therefore asked to remove the rest of the LHC beam pipe while keeping the VELO portion of the pipe completely isolated. This work...

  15. LHCb: DIRAC Secure Distributed Platform

    CERN Multimedia

    Casajus, A

    2009-01-01

    DIRAC, the LHCb community grid solution, provides access to a vast amount of computing and storage resources to a large number of users. In DIRAC users are organized in groups with different needs and permissions. In order to ensure that only allowed users can access the resources and to enforce that there are no abuses, security is mandatory. All DIRAC services and clients use secure connections that are authenticated using certificates and grid proxies. Once a client has been authenticated, authorization rules are applied to the requested action based on the presented credentials. These authorization rules and the list of users and groups are centrally managed in the DIRAC Configuration Service. Users submit jobs to DIRAC using their local credentials. From then on, DIRAC has to interact with different Grid services on behalf of this user. DIRAC has a proxy management service where users upload short-lived proxies to be used when DIRAC needs to act on behalf of them. Long duration proxies are uploaded by us...

  16. LHCb : Full Experiment System Test

    CERN Multimedia

    Cattaneo, M

    2009-01-01

    LHCb had been planning to commission its High Level Trigger software and Data Quality monitoring procedures using real collisions data from the LHC pilot run. Following the LHC incident on 19th September 2008, it was decided to commission the system using simulated data. This “Full Experiment System Test” consists of: - Injection of simulated minimum bias events into the full HLT farm, after selection by a simulated Level 0 trigger. - Processing in the HLT farm to achieve the output rate expected for nominal LHC luminosity running, sustained over the typical duration of an LHC fill. - Real time Data Quality validation of the HLT output, validation of calibration and alignment parameters for use in the reconstruction. - Transmission of the event data, calibration data and book-keeping information to Tier1 sites and full reconstruction of the event data. - Data Quality validation of the reconstruction output. We will report on the preparations and results of FEST09, and on the status of commissioning for no...

  17. LHCb migration from Subversion to Git

    Science.gov (United States)

    Clemencic, M.; Couturier, B.; Closier, J.; Cattaneo, M.

    2017-10-01

    Due to user demand and to support new development workflows based on code review and multiple development streams, LHCb decided to port the source code management from Subversion to Git, using the CERN GitLab hosting service. Although tools exist for this kind of migration, LHCb specificities and development models required careful planning of the migration, development of migration tools, changes to the development model, and redefinition of the release procedures. Moreover we had to support a hybrid situation with some software projects hosted in Git and others still in Subversion, or even branches of one projects hosted in different systems. We present the way we addressed the special LHCb requirements, the technical details of migrating large non standard Subversion repositories, and how we managed to smoothly migrate the software projects following the schedule of each project manager.

  18. LHCbDIRAC as Apache Mesos microservices

    CERN Multimedia

    Couturier, Ben

    2016-01-01

    The LHCb experiment relies on LHCbDIRAC, an extension of DIRAC, to drive its offline computing. This middleware provides a development framework and a complete set of components for building distributed computing systems. These components are currently installed and ran on virtual machines (VM) or bare metal hardware. Due to the increased load of work, high availability is becoming more and more important for the LHCbDIRAC services, and the current installation model is showing its limitations. Apache Mesos is a cluster manager which aims at abstracting heterogeneous physical resources on which various tasks can be distributed thanks to so called "framework". The Marathon framework is suitable for long running tasks such as the DIRAC services, while the Chronos framework meets the needs of cron-like tasks like the DIRAC agents. A combination of the service discovery tool Consul together with HAProxy allows to expose the running containers to the outside world while hiding their dynamic placements. Such an arc...

  19. Novel strategies at Lhcb for particle identification

    CERN Document Server

    Ferrari, Fabio

    2017-01-01

    The LHCb experiment at the Large Hadron Collider (LHC) is performing high precision measurements in the avour sector. An excellent performance of the particle identication (PID) detectors as well as the development of new data taking techniques are of fundamental importance in order to cope with increasingly harder challenges posed by the LHC Run 2. The approach of data-driven calibration of particle identication performance at LHCb has changed significantly from Run 1 to Run 2 and calibration samples are now selected directly in the LHCb high-level trigger. This change of data-taking paradigm enables larger calibration samples with respect to Run 1 to be collected, giving access to low-level detector informations useful for studies of systematic effects, while retaining the same (or improving) the PID performances observed Run 1.

  20. LHCb Data Replication During SC3

    CERN Multimedia

    Smith, A

    2006-01-01

    LHCb's participation in LCG's Service Challenge 3 involves testing the bulk data transfer infrastructure developed to allow high bandwidth distribution of data across the grid in accordance with the computing model. To enable reliable bulk replication of data, LHCb's DIRAC system has been integrated with gLite's File Transfer Service middleware component to make use of dedicated network links between LHCb computing centres. DIRAC's Data Management tools previously allowed the replication, registration and deletion of files on the grid. For SC3 supplementary functionality has been added to allow bulk replication of data (using FTS) and efficient mass registration to the LFC replica catalog.Provisional performance results have shown that the system developed can meet the expected data replication rate required by the computing model in 2007. This paper details the experience and results of integration and utilisation of DIRAC with the SC3 transfer machinery.

  1. Anti-deuteron sensitivity studies at LHCb

    CERN Multimedia

    Baker, Sophie Katherine

    2018-01-01

    Measurements of anti-deuterons in collider experiments can help to reduce systematic uncertainties in indirect searches for dark matter. Two predominant unknowns in these searches are the production of secondary anti-deuterons in the cosmos from spallation processes, and anti-deuteron production from annihilating dark matter. LHCb is a forward spectrometer on the LHC ring, designed to measure b-hadron decays from high energy proton-proton collisions. With the detector's excellent particle identification capabilities, deuteron and anti-deuteron measurements at LHCb could help to parametrise the two cosmological processes. Recent studies of (anti-)deuteron identification at LHCb and the prospects for measuring prompt (anti-)deuterons from pp-collisions will be presented, as well as a working analysis of b-baryrons decaying to deuterons.

  2. Implications of LHCb measurements and future prospects

    CERN Document Server

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Karavichev, O; Karbach, T M; Kashchuk, A; Kechadi, T; Kenyon, I R; Kerzel, U; Ketel, T; Keune, A; Khanji, B; Kihm, T; Kluit, R; Kochebina, O; Komarov, V; Koopman, R F; Koppenburg, P; Korolev, M; Kos, J; Kozlinskiy, A; Kravchuk, L; Kreplin, K; Kreps, M; Kristic, R; Krocker, G; Krokovny, P; Kruse, F; Kucharczyk, M; Kudenko, Y; Kudryavtsev, V; Kvaratskheliya, T; La Thi, V N; Lacarrere, D; Lafferty, G; Lai, A; Lambert, D; Lambert, R W; Lanciotti, E; Landi, L; Lanfranchi, G; Langenbruch, C; Laptev, S; Latham, T; Lax, I; Lazzeroni, C; Le Gac, R; van Leerdam, J; Lees, J -P; Lefèvre, R; Leflat, A; Lefrançois, J; Leroy, O; Lesiak, T; Li, Y; Li Gioi, L; Likhoded, A; Liles, M; Lindner, R; Linn, C; Liu, B; Liu, G; von Loeben, J; Lopes, J H; Lopez Asamar, E; Lopez-March, N; Lu, H; Luisier, J; Luo, H; Mac Raighne, A; Machefert, F; Machikhiliyan, I V; Maciuc, F; Maev, O; Maino, M; Malde, S; Manca, G; Mancinelli, G; Mangiafave, N; Marconi, U; Märki, R; Marks, J; Martellotti, G; Martens, A; Martín Sánchez, A; Martinelli, M; Martinez Santos, D; Martins Tostes, D; Massafferri, A; Matev, R; Mathe, Z; Matteuzzi, C; Matveev, M; Maurice, E; Mauricio, J; Mazurov, A; McCarthy, J; McNulty, R; Meadows, B; Meissner, M; Mejia, H; Mendez-Munoz, V; Merk, M; Milanes, D A; Minard, M -N; Molina Rodriguez, J; Monteil, S; Moran, D; Morawski, P; Mountain, R; Mous, I; Muheim, F; Mul, F; Müller, K; Munneke, B; Muresan, R; Muryn, B; Muster, B; Naik, P; Nakada, T; Nandakumar, R; Nasteva, I; Nawrot, A; Needham, M; Neufeld, N; Nguyen, A D; Nguyen, T D; Nguyen-Mau, C; Nicol, M; Niess, V; Nikitin, N; Nikodem, T; Nikolaiko, Y; Nisar, S; Nomerotski, A; Novoselov, A; Oblakowska-Mucha, A; Obraztsov, V; Oggero, S; Ogilvy, S; Okhrimenko, O; Oldeman, R; Orlandea, M; Ostankov, A; Otalora Goicochea, J M; van Overbeek, M; Owen, P; Pal, B K; Palano, A; Palutan, M; Panman, J; Papanestis, A; Pappagallo, M; Parkes, C; Parkinson, C J; Passaleva, G; Patel, G D; Patel, M; Patrick, G N; Patrignani, C; Pavel-Nicorescu, C; Pazos Alvarez, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perego, D L; Perez Trigo, E; Pérez-Calero Yzquierdo, A; Perret, P; Perrin-Terrin, M; Pessina, G; Petridis, K; Petrolini, A; van Petten, O; Phan, A; Picatoste Olloqui, E; Piedigrossi, D; Pietrzyk, B; Pilař, T; Pinci, D; Playfer, S; Plo Casasus, M; Polci, F; Polok, G; Poluektov, A; Polycarpo, E; Popov, D; Popovici, B; Potterat, C; Powell, A; Prisciandaro, J; Pugatch, M; Pugatch, V; Puig Navarro, A; Qian, W; Rademacker, J H; Rakotomiaramanana, B; Rangel, M S; Raniuk, I; Rauschmayr, N; Raven, G; Redford, S; Reid, M M; dos Reis, A C; Rethore, F; Ricciardi, S; Richards, A; Rinnert, K; Rives Molina, V; Roa Romero, D A; Robbe, P; Rodrigues, E; Rodriguez Perez, P; Roeland, E; Rogers, G J; Roiser, S; Romanovsky, V; Romero Vidal, A; de Roo, K; Rouvinet, J; Roy, L; Rudloff, K; Ruf, T; Ruiz, H; Sabatino, G; Saborido Silva, J J; Sagidova, N; Sail, P; Saitta, B; Salzmann, C; Sanmartin Sedes, B; Santacesaria, R; Santamarina Rios, C; Santovetti, E; Saornil Gamarra, S; Sapunov, M; Saputi, A; Sarti, A; Satriano, C; Satta, A; Savidge, T; Savrie, M; Schaack, P; Schiller, M; Schimmel, A; Schindler, H; Schleich, S; Schlupp, M; Schmelling, M; Schmidt, B; Schneider, O; Schneider, T; Schopper, A; Schuijlenburg, H; Schune, M -H; Schwemmer, R; Sciascia, B; Sciubba, A; Seco, M; Semennikov, A; Senderowska, K; Sepp, I; Serra, N; Serrano, J; Seyfert, P; Shao, B; Shapkin, M; Shapoval, I; Shatalov, P; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, O; Shevchenko, V; Shires, A; Sigurdsson, S; Silva Coutinho, R; Skwarnicki, T; Slater, M W; Sluijk, T; Smith, N A; Smith, E; Smith, M; Sobczak, K; Sokoloff, M D; Soler, F J P; Soomro, F; Souza, D; Souza De Paula, B; Spaan, B; Sparkes, A; Spradlin, P; Squerzanti, S; Stagni, F; Stahl, S; Steinkamp, O; Stenyakin, O; Stoica, S; Stone, S; Storaci, B; Straticiuc, M; Straumann, U; Subbiah, V K; Swientek, S; Szczekowski, M; Szczypka, P; Szumlak, T; T'Jampens, S; Teklishyn, M; Teodorescu, E; Teubert, F; Thomas, C; Thomas, E; Tikhonov, A; van Tilburg, J; Tisserand, V; Tobin, M; Tocut, V; Tolk, S; Tonelli, D; Topp-Joergensen, S; Torr, N; Tournefier, E; Tourneur, S; Tran, M T; Tresch, M; Tsaregorodtsev, A; Tsopelas, P; Tuning, N; Ubeda Garcia, M; Ukleja, A; Ullaland, O; Urner, D; Uwer, U; Vagnoni, V; Valenti, G; Vazquez Gomez, R; Vazquez Regueiro, P; Vecchi, S; Velthuis, J J; Veltri, M; Veneziano, G; Vesterinen, M; Viaud, B; Vieira, D; Vilasis-Cardona, X; Vink, W; Volkov, S; Volkov, V; Vollhardt, A; Volyanskyy, D; Voong, D; Vorobyev, A; Vorobyev, V; Voß, C; Voss, H; Vouters, G; Waldi, R; Wallace, R; Wandernoth, S; Wang, J; Ward, D R; Warda, K; Watson, N K; Webber, A D; Websdale, D; Wenerke, P; Whitehead, M; Wicht, J; Wiedner, D; Wiggers, L; Wilkinson, G; Williams, M P; Williams, M; Wilson, F F; Wishahi, J; Witek, M; Witzeling, W; Wotton, S A; Wright, S; Wu, S; Wyllie, K; Xie, Y; Xing, Z; Xue, T; Yang, Z; Young, R; Yuan, X; Yushchenko, O; Zangoli, M; Zappon, F; Zavertyaev, M; Zeng, M; Zhang, F; Zhang, L; Zhang, W C; Zhang, Y; Zhelezov, A; Zhong, L; Zverev, E; Zvyagin, A; Zwart, A; Bharucha, A; Bigi, I.I.; Bobeth, C; Bobrowski, M; Brod, Joachim; Buras, A J; Davies, C T H; Datta, A.; Delaunay, C; Descotes-Genon, S; Ellis, J; Feldmann, T; Fleischer, R; Gedalia, O; Girrbach, J; Guadagnoli, D; Hiller, G; Hochberg, Y; Hurth, T; Isidori, G; Jager, S; Jung, M; Kagan, A; Kamenik, J F; Lenz, A; Ligeti, Z; London, D; Mahmoudi, F; Matias, J; Nandi, S; Nir, Y; Paradisi, P; Perez, G; Petrov, A A; Rattazzi, R; Sharpe, S R; Silvestrini, L; Soni, A; Straub, D M; van Dyk, D; Virto, J; Wang, Y M; Weiler, A; Zupan, J

    2013-01-01

    During 2011 the LHCb experiment at CERN collected $1.0 {\\mbox{fb}^{-1}}$ of $\\sqrt{s} = 7 {\\mathrm{\\,Te\\kern -0.1em V}}$ $pp$ collisions. Due to the large heavy quark production cross-sections, these data provide unprecedented samples of heavy flavoured hadrons. The first results from LHCb have made a significant impact on the flavour physics landscape and have definitively proved the concept of a dedicated experiment in the forward region at a hadron collider. This document discusses the implications of these first measurements on classes of extensions to the Standard Model, bearing in mind the interplay with the results of searches for on-shell production of new particles at ATLAS and CMS. The physics potential of an upgrade to the LHCb detector, which would allow an order of magnitude more data to be collected, is emphasised.

  3. Status and prospects for strange physics at LHCb

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    Rare decays are fundamental probes of physics beyond the Standard Model. We present the current status of rare decays studies at the LHCb experiment and discuss a possible picture emerging from these measurements. The expanding LHCb program of strange physics, in particular of their rare decays, provides a unique and complementary probe to test the SM with respect to the beauty and charm. We present recent results on rare strange hadrons decays exploiting the LHCb Run I data. We then present prospects for strange physics with the LHCb Run II data and after the improvements in the trigger for the LHCb Upgrade.

  4. Measurement and analysis of high energy radiation through activation detectors. Application in dosimetry; Sur la mesure et l'analyse des rayonnements de haute energie par detecteurs a activation. Application a la dosimetrie

    Energy Technology Data Exchange (ETDEWEB)

    Sklavenitis, L. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-10-15

    This work is concerned with the possibility of measurement and analysis of radiation fluences within objects of small volume submitted to a high energy proton beam. The first part, consecrated to the establishment of a method of analysis, comprises a detailed study of the radiation nature and energy spectra as well as of the various dosimetry methods. In order to select a group of detectors, high energy nuclear reactions were systematically studied and for some of them cross sections were measured or calculated: for example the cross section of the reaction {sup 11}B (p,n) {sup 11}C between 150 and 3000 MeV and of the reaction {sup 34}S (p,2pn) {sup 32}P between 50 and 3000 MeV. The second part is relative to the application of the fore-mentioned analysis to radiation within a tissue equivalent phantom irradiated by 3 GeV protons. This analysis is sufficiently detailed to allow the reconstitution of the absorbed doses, the dose equivalent and, contingent on a better knowledge of the dose due to heavy particles, the quality factors. It allowed also to follow the evolution of the various dosimetric data as a function of the depth inside the phantom and to verify calculations already done by other researchers. The comparison of the measured doses and the corresponding detector activities revealed the possibility that some detectors could give directly the absorbed dose, or even the dose equivalent, by a simple activity measurement. (author) [French] Le travail porte sur la possibilite de mesure et d'analyse, a l'aide de detecteurs a activation, des fluences de rayonnements a l'interieur d'un objet de petit volume soumis a un faisceau de protons de tres haute energie. La premiere partie, consacree a la mise au point de la methode d'analyse des fluences, comporte une etude detaillee de la nature des rayonnements et de leurs spectres energetiques ainsi que des differentes methodes de dosimetrie. Pour arriver au choix d'un groupe de

  5. Measurement and analysis of high energy radiation through activation detectors. Application in dosimetry; Sur la mesure et l'analyse des rayonnements de haute energie par detecteurs a activation. Application a la dosimetrie

    Energy Technology Data Exchange (ETDEWEB)

    Sklavenitis, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-10-15

    This work is concerned with the possibility of measurement and analysis of radiation fluences within objects of small volume submitted to a high energy proton beam. The first part, consecrated to the establishment of a method of analysis, comprises a detailed study of the radiation nature and energy spectra as well as of the various dosimetry methods. In order to select a group of detectors, high energy nuclear reactions were systematically studied and for some of them cross sections were measured or calculated: for example the cross section of the reaction {sup 11}B (p,n) {sup 11}C between 150 and 3000 MeV and of the reaction {sup 34}S (p,2pn) {sup 32}P between 50 and 3000 MeV. The second part is relative to the application of the fore-mentioned analysis to radiation within a tissue equivalent phantom irradiated by 3 GeV protons. This analysis is sufficiently detailed to allow the reconstitution of the absorbed doses, the dose equivalent and, contingent on a better knowledge of the dose due to heavy particles, the quality factors. It allowed also to follow the evolution of the various dosimetric data as a function of the depth inside the phantom and to verify calculations already done by other researchers. The comparison of the measured doses and the corresponding detector activities revealed the possibility that some detectors could give directly the absorbed dose, or even the dose equivalent, by a simple activity measurement. (author) [French] Le travail porte sur la possibilite de mesure et d'analyse, a l'aide de detecteurs a activation, des fluences de rayonnements a l'interieur d'un objet de petit volume soumis a un faisceau de protons de tres haute energie. La premiere partie, consacree a la mise au point de la methode d'analyse des fluences, comporte une etude detaillee de la nature des rayonnements et de leurs spectres energetiques ainsi que des differentes methodes de dosimetrie. Pour arriver au choix d'un groupe de detecteurs, une etude systematique des

  6. LHCb PID Upgrade Technical Design Report

    CERN Document Server

    LHCb Collaboration

    2013-01-01

    The LHCb upgrade will take place in the second long shutdown of the LHC, currently scheduled to begin in 2018. The upgrade will enable the experiment to run at luminosities of $2 \\times 10^{33}cm^{-2}s^{-1}$ and will read out data at a rate of 40MHz into a exible software-based trigger. All sub-detectors of LHCb will be re-designed to comply with these new operating conditions. This Technical Design Report presents the upgrade plans of the Ring Imaging Cherenkov (RICH) system, the calorimeter system and the muon system, which together provide the particle identication capabilities of the experiment.

  7. Flavour Tagging developments within the LHCb experiment

    CERN Document Server

    Grabalosa, Marc

    Flavour Tagging at the LHCb experiment is a fundamental tool for the measurement of B oscillations and the study of CP violation. This document explains the development of different tagging techniques and the different strategies used to combine them to determine the flavour of the B meson as precisely as possible. The response of the tagging algorithms also needs to be optimized and calibrated. Both procedures are described using the available LHCb datasets corresponding to various integrated luminosities. First results on the tagging performances are shown for different control channels and physics measurements.

  8. Measurements of CPT Violation at LHCb

    CERN Document Server

    INSPIRE-00260865

    2017-01-01

    Recent measurements of CPT violation and Lorentz symmetry breaking in $B^0-\\bar{B}^0$ mixing and $B^0_s-\\bar{B}^0_s$ mixing, obtained from data taken by the LHCb experiment, are highlighted. The results are expressed in terms of the Standard-Model Extension (SME) coefficients, which incorporate both CPT and Lorentz violation. Due to the large boost of the $B$ mesons at LHCb, the SME coefficients can be determined with high precision. The bounds on these coefficients are improved significantly compared to previous measurements.

  9. Forward physics with the LHCb experiment

    International Nuclear Information System (INIS)

    Volyanskyy, Dmytro

    2013-01-01

    Due to its unique pseudorapidity coverage and the ability to perform measurements at low transverse momenta p T , the LHCb detector allows a unique insight into particle production in the forward region at the LHC. Using large samples of proton-proton collision data accumulated at √(s) = 7TeV, the LHCb collaboration has performed a series of dedicated analyses providing important input to the knowledge of the parton density functions, underlying event activity, low Bjorken-x QCD dynamics and exclusive processes. Some of these are briefly summarised here.

  10. Forward physics with the LHCb experiment

    Energy Technology Data Exchange (ETDEWEB)

    Volyanskyy, Dmytro [Max-Planck-Institut fuer Kernphysik, PO Box 103980, 69029 Heidelberg(Germany); Collaboration: LHCb Collaboration

    2013-04-15

    Due to its unique pseudorapidity coverage and the ability to perform measurements at low transverse momenta p{sub T}, the LHCb detector allows a unique insight into particle production in the forward region at the LHC. Using large samples of proton-proton collision data accumulated at {radical}(s) = 7TeV, the LHCb collaboration has performed a series of dedicated analyses providing important input to the knowledge of the parton density functions, underlying event activity, low Bjorken-x QCD dynamics and exclusive processes. Some of these are briefly summarised here.

  11. Forward physics with the LHCb experiment

    CERN Document Server

    INSPIRE-00312886

    2012-01-01

    Due to its unique pseudorapidity coverage and the ability to perform measurements at low transverse momenta $p_{\\rm T}$, the LHCb detector allows a unique insight into particle production in the forward region at the LHC. Using large samples of proton-proton collision data accumulated at $\\sqrt{s}=7$ TeV, the LHCb collaboration has performed a series of dedicated analyses providing important input to the knowledge of the parton density functions, underlying event activity, low Bjorken-x QCD dynamics and exclusive processes. Some of these are briefly summarised here.

  12. LHCb: Alignment of the LHCb Detector with Kalman Filter Fitted Tracks

    CERN Multimedia

    Amoraal, J; Hulsbergen, W; Needham, M; Nicolas, L; Pozzi, S; Raven, G; Vecchi, S

    2009-01-01

    We report on an implementation of a global chisquare algorithm for the simultaneous alignment of all tracking systems in the LHCb detector. Our algorithm uses hit residuals from the standard LHCb track fit which is based on a Kalman filter. The algorithm is implemented in the LHCb reconstruction framework and exploits the fact that all sensitive detector elements have the same geometry interface. A vertex constraint is implemented by fitting tracks to a common point and propagating the change in track parameters to the hit residuals. To remove unconstrained or poorly constrained degrees of freedom (so-called weak modes) the average movements of (subsets of) alignable detector elements can be fixed with Lagrange constraints. Alternatively, weak modes can be removed with a cutoff in the eigenvalue spectrum of the second derivative of the chisquare. As for all LHCb reconstruction and analysis software the configuration of the algorithm is done in python and gives detailed control over the selection of alignable ...

  13. LHCb: Magnetic Distortion Measurement System of the LHCb RICH2 Detector

    CERN Multimedia

    Storaci, B

    2007-01-01

    The LHCb experiment at the CERN LHC collider is optimized for the study of CP violation and rare B-decays. Two Ring Imaging Cherenkov detectors provide particle identification in the momentum range 1-100 GeV/c

  14. LHCb: Optimization and Calibration of Flavour Tagging Algorithms for the LHCb experiment

    CERN Multimedia

    Falabella, A

    2013-01-01

    The LHCb purposes are to make precise measurements in $B$ and $D$ meson decays. In particular in time-dependent CP violation studies the determination of $B$ flavour at production ("Flavour Tagging") is fundamental. The performances and calibration of the flavour tagging algorithms with 2011 data collected by LHCb are reported. The performances of the flavour tagging algorithms on the relevant CP violation and asymmetry studies are also reported.

  15. LHCb in the International Particle Physics Masterclasses

    CERN Document Server

    Couturier, Ben

    2016-01-01

    The Large Hadron Collider Beauty (LHCb) Experiment joined the International Particle Physics Masterclass programme in 2013. The experiment proposed the measurement of the D0 meson lifetime, using real data gathered at the Large Hadron Collider in 2012. We describe the exercise as well as the lessons learned during this first participation in the International Masterclass programme.

  16. Prospects for Heavy Ion Physics with LHCb

    Energy Technology Data Exchange (ETDEWEB)

    Manca, Giulia

    2016-12-15

    We will discuss the potential of the LHCb experiment in the field of Heavy Ion physics. We will analyse three different scenarios which can be explored by the experiment, namely collisions of protons with lead, lead with lead and proton or lead beams with a gas injected in the interaction region. We will also show results in some of these configurations.

  17. LHCb Kalman Filter cross architecture studies

    Science.gov (United States)

    Hugo, Daniel; Pérez, Cámpora

    2017-10-01

    The 2020 upgrade of the LHCb detector will vastly increase the rate of collisions the Online system needs to process in software, in order to filter events in real time. 30 million collisions per second will pass through a selection chain, where each step is executed conditional to its prior acceptance. The Kalman Filter is a fit applied to all reconstructed tracks which, due to its time characteristics and early execution in the selection chain, consumes 40% of the whole reconstruction time in the current trigger software. This makes the Kalman Filter a time-critical component as the LHCb trigger evolves into a full software trigger in the Upgrade. I present a new Kalman Filter algorithm for LHCb that can efficiently make use of any kind of SIMD processor, and its design is explained in depth. Performance benchmarks are compared between a variety of hardware architectures, including x86_64 and Power8, and the Intel Xeon Phi accelerator, and the suitability of said architectures to efficiently perform the LHCb Reconstruction process is determined.

  18. Flavour Tagging Algorithms and Performances in LHCb

    CERN Document Server

    Calvi, M; Musy, M

    2007-01-01

    In this note we describe the general characteristics of the LHCb flavour tagging algorithms and summarize the tagging performances on the Monte Carlo samples generated for the Data Challenge 2004 in different decay channels. We also discuss some systematics effects and possible methods to extract the mistag fraction in real data.

  19. LHCb RICH1 Engineering Design Review Report

    CERN Document Server

    Brook, N; Metlica, F; Muir, A; Phillips, A; Buckley, A; Gibson, V; Harrison, K; Jones, C R; Katvars, S G; Lazzeroni, C; Storey, J; Ward, CP; Wotton, S; Alemi, M; Arnabaldi, C; Bellunato, T F; Calvi, M; Matteuzzi, C; Musy, M; Negri, P; Perego, D L; Pessina, G; Chamonal, R; Eisenhardt, S; Lawrence, J; McCarron, J; Muheim, F; Playfer, S; Walker, A; Cuneo, S; Fontanelli, F; Gracco, Valerio; Mini, G; Musico, P; Petrolini, A; Sannino, M; Bates, A; MacGregor, A; O'Shea, V; Parkes, C; Paterson, S; Petrie, D; Pickford, A; Rahman, M; Soler, F; Allebone, L; Barber, J H; Cameron, W; Clark, D; Dornan, Peter John; Duane, A; Egede, U; Hallam, R; Howard, A; Plackett, R; Price, D; Savidge, T; Vidal-Sitjes, G; Websdale, D M; Adinolfi, M; Bibby, J H; Cioffi, C; Gligorov, Vladimir V; Harnew, N; Harris, F; McArthur, I A; Newby, C; Ottewell, B; Rademacker, J; Senanayake, R; Somerville, L P; Soroko, A; Smale, N J; Topp-Jørgensen, S; Wilkinson, G; Yang, S; Benayoun, M; Khmelnikov, V A; Obraztsov, V F; Densham, C J; Easo, S; Franek, B; Kuznetsov, G; Loveridge, P W; Morrow, D; Morris, JV; Papanestis, A; Patrick, G N; Woodward, M L; Aglieri-Rinella, G; Albrecht, A; Braem, André; Campbell, M; D'Ambrosio, C; Forty, R W; Frei, C; Gys, Thierry; Jamet, O; Kanaya, N; Losasso, M; Moritz, M; Patel, M; Piedigrossi, D; Snoeys, W; Ullaland, O; Van Lysebetten, A; Wyllie, K

    2005-01-01

    This document describes the concepts of the engineering design to be adopted for the upstream Ring Imaging Cherenkov detector (RICH1) of the reoptimized LHCb detector. Our aim is to ensure that coherent solutions for the engineering design and integration for all components of RICH1 are available, before proceeding with the detailed design of these components.

  20. Mounting LHCb hadron calorimeter scintillating tiles

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    Scintillating tiles are carefully mounted in the hadronic calorimeter for the LHCb detector. These calorimeters measure the energy of particles that interact via the strong force, called hadrons. The detectors are made in a sandwich-like structure where these scintillator tiles are placed between metal sheets.

  1. LHCb Vertex Locator Upgrade Work Report

    CERN Document Server

    Estrada, Michael

    2017-01-01

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

  2. LHCb Online event processing and filtering

    CERN Document Server

    Alessio, F; Brarda, L; Frank, M; Franek, B; Galli, D; Gaspar, C; Van Herwijnen, E; Jacobsson, R; Jost, B; Köstner, S; Moine, G; Neufeld, N; Somogyi, P; Stoica, R; Suman, S

    2008-01-01

    The first level trigger of LHCb accepts one million events per second. After preprocessing in custom FPGA-based boards these events are distributed to a large farm of PC-servers using a high-speed Gigabit Ethernet network. Synchronisation and event management is achieved by the Timing and Trigger system of LHCb. Due to the complex nature of the selection of B-events, which are the main interest of LHCb, a full event-readout is required. Event processing on the servers is parallelised on an event basis. The reduction factor is typically 1/500. The remaining events are forwarded to a formatting layer, where the raw data files are formed and temporarily stored. A small part of the events is also forwarded to a dedicated farm for calibration and monitoring. The files are subsequently shipped to the CERN Tier0 facility for permanent storage and from there to the various Tier1 sites for reconstruction. In parallel files are used by various monitoring and calibration processes running within the LHCb Online system. ...

  3. User analysis of LHCb data with Ganga

    CERN Document Server

    Maier, A; Cowan, G; Egede, U; Elmsheuser, J; Gaidioz, B; Harrison, K; Lee, H -C; Liko, D; Moscicki, J; Muraru, A; Pajchel, K; Reece, W; Samset, B; Slater, M; Soroko, A; van der Ster, D; Williams, M; Tan, C L

    2010-01-01

    GANGA (http://cern.ch/ganga) is a job-management tool that offers a simple, efficient and consistent user analysis tool in a variety of heterogeneous environments: from local clusters to global Grid systems. Experiment specific plug-ins allow GANGA to be customised for each experiment. For LHCb users GANGA is the officially supported and advertised tool for job submission to the Grid. The LHCb specific plug-ins allow support for end-to-end analysis helping the user to perform his complete analysis with the help of GANGA. This starts with the support for data selection, where a user can select data sets from the LHCb Bookkeeping system. Next comes the set up for large analysis jobs: with tailored plug-ins for the LHCb core software, jobs can be managed by the splitting of these analysis jobs with the subsequent merging of the resulting files. Furthermore, GANGA offers support for Toy Monte-Carlos to help the user tune their analysis. In addition to describing the GANGA architecture, typical usage patterns with...

  4. CP violation in $b$ hadrons at LHCb

    CERN Document Server

    Hicheur, Adlene

    2017-01-01

    The most recent results on $CP$ violation in b hadrons obtained by the LHCb Collaboration with Run I and years 2015-2016 of Run II are reviewed. The different types of violation are covered by the studies presented in this paper.

  5. The LHCb VELO analogue transmission line

    International Nuclear Information System (INIS)

    Bay, A.; Borel, J.; Buytaert, J.; De Laere, S.; Frei, R.; Haefeli, G.; Koppenburg, P.; Locatelli, L.; Schneider, O.; Zehr, F.

    2010-01-01

    The Vertex Locator is one of the most important sub-detectors of the LHCb experiment, which is devoted to B physics. The signals from the silicon strip sensors are multiplexed at 40 MHz and transported by 60 m copper lines to the counting stations placed in a radiation safe area. This paper describes the development of this long transmission line and its performance.

  6. LHCb Conditions database operation assistance systems

    International Nuclear Information System (INIS)

    Clemencic, M; Shapoval, I; Cattaneo, M; Degaudenzi, H; Santinelli, R

    2012-01-01

    The Conditions Database (CondDB) of the LHCb experiment provides versioned, time dependent geometry and conditions data for all LHCb data processing applications (simulation, high level trigger (HLT), reconstruction, analysis) in a heterogeneous computing environment ranging from user laptops to the HLT farm and the Grid. These different use cases impose front-end support for multiple database technologies (Oracle and SQLite are used). Sophisticated distribution tools are required to ensure timely and robust delivery of updates to all environments. The content of the database has to be managed to ensure that updates are internally consistent and externally compatible with multiple versions of the physics application software. In this paper we describe three systems that we have developed to address these issues. The first system is a CondDB state tracking extension to the Oracle 3D Streams replication technology, to trap cases when the CondDB replication was corrupted. Second, an automated distribution system for the SQLite-based CondDB, providing also smart backup and checkout mechanisms for the CondDB managers and LHCb users respectively. And, finally, a system to verify and monitor the internal (CondDB self-consistency) and external (LHCb physics software vs. CondDB) compatibility. The former two systems are used in production in the LHCb experiment and have achieved the desired goal of higher flexibility and robustness for the management and operation of the CondDB. The latter one has been fully designed and is passing currently to the implementation stage.

  7. Oil-leak detector; Detecteur de fuite d'huile

    Energy Technology Data Exchange (ETDEWEB)

    Da Costa Viera, D; Fierard, P; Bacchiani, L; Lions, N [Commissariat a l' Energie Atomique, Cadarache (France). Centre d' Etudes Nucleaires

    1967-07-01

    This apparatus is designed to set off an alarm when the oil level in a reservoir exceeds or falls short of a given value. The detection system consists of a condenser whose plates are separated by air or by oil, the condenser being immersed or non-immersed. A very small change in capacity (of the order of 1 pF for a height of oil of 1 cm) should be detected with respect to the high capacity of the connecting cable. An application for a patent has been made for this apparatus which makes it possible to detect small changes in capacity. (authors) [French] Cet appareil est destine a declencher une alarme lorsque le niveau d'huile d'un reservoir est superieur ou inferieur a une certaine valeur. Le systeme de detection comporte un condensateur dont les armatures sont separees par de l'air ou de l'huile, le condensateur etant immerge ou non. Une tres faible variation de capacite (de l'ordre de 1 pF pour 1 cm de hauteur d'huile) doit etre detectee par rapport a une capacite importante due au cable de liaison. Cet appareil qui permet de deceler ces faibles variations de capacite, fait l'objet d'une demande de brevet. (auteurs)

  8. ARIADNE: a Tracking System for Relationships in LHCb Metadata

    CERN Document Server

    Shapoval, I; Cattaneo, M

    2014-01-01

    The data processing model of the LHCb experiment implies handling of an evolving set of heterogeneous metadata entities and relationships between them. The entities range from software and databases states to architecture specificators and software/data deployment locations. For instance, there is an important relationship between the LHCb Conditions Database (CondDB), which provides versioned, time dependent geometry and conditions data, and the LHCb software, which is the data processing applications (used for simulation, high level triggering, reconstruction and analysis of physics data). The evolution of CondDB and of the LHCb applications is a weakly-homomorphic process. It means that relationships between a CondDB state and LHCb application state may not be preserved across different database and application generations. These issues may lead to various kinds of problems in the LHCb production, varying from unexpected application crashes to incorrect data processing results. In this paper we present Ari...

  9. {beta} {gamma} porch detector; Detecteur portique {beta} {gamma}

    Energy Technology Data Exchange (ETDEWEB)

    Roulet, R [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1963-07-01

    This device is to be placed at the outside of reactors, hot laboratories and others where radioactive products are treated; it is intended to give the alarm when someone, passing through the porch is greatly contaminated, or carries, without his knowing, a radioactive substance. Being to be used in places where there might be an important ground noise, this device is provided with an automatic offset of this noise; an adjusting system of sensitivity allows to obtain a 15 {mu}Ci in {gamma} and 10 {mu}Ci in {beta} radioactive source, passing through the porch at the normal speed at which man is walking. A battery, set in buffer, allows working of the device, even when current is off. (author) [French] Cet appareil est destine a etre place a la sortie des reacteurs, laboratoires chauds ou autres laboratoires travaillant sur des produits radioactifs; son but est de donner une alarme lorsque quelqu'un, passant sous le portique, presente une forte contamination, ou surtout transporte par inadvertance un corps radioactif. Cet appareil devant etre utilise dans les lieux ou peut regner un bruit de fond important, possede une compensation automatique de ce bruit de fond; un reglage de la sensibilite permet d'obtenir au mieux un declenchement pour une source. de 15 {mu}Ci en {gamma} et 10 {mu}Ci en {beta} passant sous le portique a la vitesse normale d'un homme qui marche. Une batterie montee en tampon permet a l'appareil de fonctionner meme en cas de coupure de courant. (auteur)

  10. ATLAS, CMS, LHCb and ALICE Career Networking Event 2015

    CERN Multimedia

    Marinov, Andrey; Strom, Derek Axel

    2015-01-01

    A networking event for alumni of the ATLAS, CMS, LHCb and ALICE experiments as well as current ATLAS/CMS/LHCb/ALICE postdocs and graduate students. This event offers an insight into career opportunities outside of academia. Various former members of the ATLAS, CMS, LHCb and ALICE collaborations will give presentations and be part of a panel discussion and elaborate on their experience in companies in a diverse range of fields (industry, finance, IT,...). Details at https://indico.cern.ch/event/440616

  11. New Physics perspectives with the upgraded LHCb detector

    International Nuclear Information System (INIS)

    Cavallero, G.

    2017-01-01

    First encouraging deviations from Standard Model have been observed by the LHCb Collaboration in the first phase of data taking. The LHCb upgrade will be crucial to conclude if New Physics exists up to ∼ O(100 TeV), thanks to the collection of a very large data sample of ∼ 50 fb"−"1 and to an innovative flexible software based trigger system. An overview of the main observables accessible to LHCb that could reveal New Physics effects is reported.

  12. LHCb: LHCb Software and Conditions Database Cross-Compatibility Tracking: a Graph-Theory Approach

    CERN Multimedia

    Cattaneo, M; Shapoval, I

    2012-01-01

    The Conditions Database (CondDB) of the LHCb experiment provides versioned, time dependent geometry and conditions data or all LHCb data processing applications (simulation, high level trigger, reconstruction, analysis). The evolution of CondDB and of the LHCb applications is a weakly-homomorphic process. It means that compatibility between a CondDB state and LHCb application state may not be preserved across different database and application generations. More over, a CondDB state by itself belongs to a complex three-dimensional phase space which evolves according to certain CondDB self-compatibility criteria, so it is sometimes difficult even to determine a self-consistent CondDB state. These compatibility issues may lead to various kinds of problems in the LHCb production, varying from unexpected application crashes to incorrect data processing results. Thus, there is a need for defining a well-established set of compatibility criteria between mentioned above entities, together with developing a compatibil...

  13. LHCb: SALT - new silicon strip readout chip for the LHCb Upgrade

    CERN Multimedia

    Swientek, K; Fiutowski, T; Idzik, M; Moron, J; Szumlak, T

    2013-01-01

    The LHCb detector, operating at the LHC proton-proton collider, has finished its Run I period. After more than two years of collision data taking the experiment accumulated corresponding integrated luminosity of around 3.1 fb$^{-1}$. The full recorded data sample will be used by physicists to search for New Physics and precise measurement of CP-violation in heavy flavor quark sector. Despite its superb performance it is clear that the LHCb experiment is statistically limited for a number of important decay channels (such as $B_d \\to K^*\\mu \\mu$ or $B_s \\to \\phi \\phi$ ). This, in turn, is related to the current data acquisition architecture which can acquire data at the top rate of 1.1 MHz at the instantaneous luminosity close to 4x10$^{32}$ [cm$^{-2}$s$^{-1}$]. The LHC machine is already capable of delivering more than one order of magnitude higher luminosity that is presently used by the LHCb. This fact led the LHCb Collaboration to preparing a proposal regarding an upgrade of the LHCb spectrometer that woul...

  14. Electroweak scale physics & exotic searches at LHCb

    CERN Document Server

    Lupton, Olli

    2018-01-01

    The LHCb detector is a single-arm forward spectrometer covering the pseudorapidity range 2–5 that is principally designed for the study of b- and c-hadrons, but which is well-suited to a wide variety of electroweak scale measurements and exotic searches that are highly complementary to other experiments at the LHC and elsewhere. Several features of the detector that are crucial for the core flavour physics programme, such as excellent vertex and momentum resolution, and a powerful trigger system, contribute to excellent jet tagging performance and sensitivity to low mass exotic states. LHCb operates at a substantially lower instantaneous luminosity than the general purpose detectors at the LHC, ATLAS and CMS, which results in a clean, low pile-up environment in which to search for physics beyond the Standard Model (SM).

  15. Matter-antimatter puzzle: LHCb improves resolution

    CERN Multimedia

    Antonella Del Rosso

    2012-01-01

    In 2010, Fermilab’s DØ experiment reported a one percent difference in the properties of matter and antimatter in decays of B mesons (that is, particles containing beauty quarks) to muons. Saturday, at the ICHEP Conference in Melbourne, the LHCb experiment at CERN presents new results, which do not confirm this anomaly and are consistent with the Standard Model predictions. The same experiment has also presented the first evidence of asymmetry arising in other decays of the same family of mesons. The image becomes clearer but the puzzle has not yet been solved.   Inside the LHCb detector. The matter-antimatter imbalance in the Universe is a very hot topic in physics. The conundrum arises from the fact that, although objects made of antimatter are not observed in the Universe, theory predicts that matter and antimatter be created equally in particle interactions and in the Big Bang. Only small deviations from this very symmetric behaviour are incorporated in the theory. E...

  16. Simulation Application for the LHCb Experiment

    CERN Document Server

    Pokorski, Witold

    2003-01-01

    We describe the LHCb detector simulation application (Gauss) based on the Geant4 toolkit. The application is built using the Gaudi software framework, which is used for all event-processing applications in the LHCb experiment. The existence of an underlying framework allows several common basic services such as persistency, interactivity, as well as detector geometry description or particle data to be shared between simulation, reconstruction and analysis applications. The main benefits of such common services are coherence between different event-processing stages as well as reduced development effort. The interfacing to Geant4 toolkit is realized through a façade (GiGa) which minimizes the coupling to the simulation engine and provides a set of abstract interfaces for configuration and event-by-event communication. The Gauss application is composed of three main blocks, i.e. event generation, detector response simulation and digitization which reflect the different stages performed during the simulation jo...

  17. Simulation Application for the LHCb Experiment

    CERN Document Server

    Belyaev, I; Easo, S; Mato, P; Palacios, J; Pokorski, Witold; Ranjard, F; Van Tilburg, J; Charpentier, Ph.

    2003-01-01

    We describe the LHCb detector simulation application (Gauss) based on the Geant4 toolkit. The application is built using the Gaudi software framework, which is used for all event-processing applications in the LHCb experiment. The existence of an underlying framework allows several common basic services such as persistency, interactivity, as well as detector geometry description or particle data to be shared between simulation, reconstruction and analysis applications. The main benefits of such common services are coherence between different event-processing stages as well as reduced development effort. The interfacing to Geant4 toolkit is realized through a facade (GiGa) which minimizes the coupling to the simulation engine and provides a set of abstract interfaces for configuration and event-by-event communication. The Gauss application is composed of three main blocks, i.e. event generation, detector response simulation and digitization which reflect the different stages performed during the simulation job...

  18. Primary Vertex Reconstruction for Upgrade at LHCb

    CERN Document Server

    Wanczyk, Joanna

    2016-01-01

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

  19. LHCb Conditions Database Operation Assistance Systems

    CERN Multimedia

    Shapoval, Illya

    2012-01-01

    The Conditions Database of the LHCb experiment (CondDB) provides versioned, time dependent geometry and conditions data for all LHCb data processing applications (simulation, high level trigger, reconstruction, analysis) in a heterogeneous computing environment ranging from user laptops to the HLT farm and the Grid. These different use cases impose front-end support for multiple database technologies (Oracle and SQLite are used). Sophisticated distribution tools are required to ensure timely and robust delivery of updates to all environments. The content of the database has to be managed to ensure that updates are internally consistent and externally compatible with multiple versions of the physics application software. In this paper we describe three systems that we have developed to address these issues: - an extension to the automatic content validation done by the “Oracle Streams” replication technology, to trap cases when the replication was unsuccessful; - an automated distribution process for the S...

  20. Radiation damage at LHCb, results and expectations

    CERN Multimedia

    Faerber, Christian

    2011-01-01

    The LHCb Detector is a single-arm spectrometer at the LHC designed to detect new physics through measuring CP violation and rare decays of heavy flavor mesons. The detector consists of vertex detector, tracking system, dipole magnet, 2 RICH detectors, em. calorimeter, hadron calorimeter, muon detector which all use different technologies and suffer differently from radiation damage. These radiation damage results and the investigation methods will be shown. The delivered luminosity till July 2011 was about 450 pb−1. The Vertex detector receives the highest particle flux at LHCb. The currents drawn by the silicon sensors are, as expected, increasing proportional to the integrated luminosity. The highest irradiaton regions of the n-bulk silicon sensors are observed to have recently undergone space charge sign inversion. The Silicon Trackers show increasing leakage currents comparable with earlier predictions. The electromagentic calorimeter and hadron calorimeter suffer under percent-level signal decrease whi...

  1. Radiation Damage in the LHCb VELO

    CERN Multimedia

    Harrison, Jon

    2011-01-01

    The VErtex LOcator (VELO) is a silicon strip detector designed to reconstruct particle tracks and vertices produced by proton-proton interactions near to the LHCb interaction point. The excellent track resolution and decay vertex separation provided by the VELO are essential to all LHCb analyses. For the integrated luminosity delivered by the LHC up to the end of $2011$ the VELO is exposed to higher particle fluences than any other silicon detector of the four major LHC experiments. These proceedings present results from radiation damage studies carried out during the first two years of data taking at the LHC. Radiation damage has been observed in all of the $88$ VELO silicon strip sensors, with many sensors showing evidence of type-inversion in the highest fluence regions. Particular attention has been given to the two \

  2. RICH High Voltages & PDF Analysis @ LHCb

    CERN Multimedia

    Fanchini, E

    2009-01-01

    In the LHCb experiment an important issue is the identification of the hadrons of the final states of the B mesons decays. Two RICH subdetectors are devoted to this task, and the Hybrid Photon Detectors (HPDs) are the photodetectors used to detect Cherenkov light. In this poster there is a description of how the very high voltage (-18 KV) supply stability used to power the HPDs is monitored. It is also presented the basics of a study which can be done with the first collision data: the analysis of the dimuons from the Drell-Yan process. This process is well known and the acceptance of the LHCb detector in terms of pseudorapidity will be very useful to improve the knowledge of the proton structure functions or, alternatively, try to estimate the luminosity from it.

  3. Particle combinations in the LHCb Upgrade trigger

    CERN Document Server

    Zhao, Fanyi

    2017-01-01

    The LHCb experiment will be upgraded during long shutdown II (2018-2020) to process inelastic proton-proton collisions at 30MHz in a software application and run at a higher instantaneous luminosity of $2\\times 10^{33}cm^{−2}s^{−1}$. Each of these collisions will contain substantially more proton-proton interactions and charged particles. It is important to identify the decay vertices of heavy-flavour hadrons produced by the primary proton-proton interaction in an efficient, CPU-performant manner. In this project, I will learn about the LHCb trigger and experimental programme and investigate alternative models for reconstructing these vertices, which may scale more efficiently to the upgraded trigger conditions than the current model.

  4. Recording the LHCb data and software dependencies

    Science.gov (United States)

    Trisovic, Ana; Couturier, Ben; Gibson, Val; Jones, Chris

    2017-10-01

    In recent years awareness of the importance of preserving the experimental data and scientific software at CERN has been rising. To support this effort, we are presenting a novel approach to structure dependencies of the LHCb data and software to make it more accessible in the long-term future. In this paper, we detail the implementation of a graph database of these dependencies. We list the implications that can be deduced from the graph mining (such as a search for the legacy software), with emphasis on data preservation. Furthermore, we introduce a methodology of recreating the LHCb data, thus supporting reproducible research and data stewardship. Finally, we describe how this information is made available to the users on a web portal that promotes data and analysis preservation and good practise with analysis documentation.

  5. V0 particle production studies at LHCb

    CERN Multimedia

    Knecht, M

    2009-01-01

    Although QCD is firmly established as the fundamental theory of strong interactions, the fragmentation process from partons into hadrons is still poorly understood. Phenomenological models tuned to Tevatron data show significant differences when extrapolated to LHC energies. The hadronization process can be probed at the LHC by studying V0 production, i.e. the production of KS mesons and Lambda hyperons. The LHCb experiment, with a rapidity range complementary to that of the other LHC detectors, offers a particularly interesting environment, covering the forward region where the existing models are very tunable but lack predictive power. The first 100 millions minimum bias events at LHCb will already provide a high-statistics and high-purity V0 sample. Measurements will include differential cross sections and production ratios for different strange particles as a function of rapidity and transverse momentum. The analysis can naturally be extended to cover heavier hyperons as well, and eventually lead, w...

  6. Beam, background and luminosity monitoring in LHCb and upgrade of the LHCb fast readout control

    CERN Document Server

    Alessio, Federico; Le Gac, R

    2011-01-01

    The work described in this thesis was developed, implemented and completely put in operations during the first year of physics data taking at the LHC. It is shown here that it is aimed at studying beam and background characteristics, monitor the global timing of the experiment, monitor online the luminosity at LHCb and monitor most the experimental conditions which can affect the LHCb physics data quality. The many functionalities of the presented systems are outlined in great detail and some selected topics of analysis are presented in order to validate the good performance. The various systems in fact showed high reliability, completeness and robustness and hence it heavily contributed to the global efficiency of the LHCb experiment and also contributed directly to the commissioning and running of the LHC machine for first physics runs. Some important concepts are also brought to attention in this thesis as possible solutions to be taken into account at the LHC. A scintillator system for beam, background an...

  7. Enabling Real-Time Analysis at LHCb

    CERN Multimedia

    Govorkova, Katya

    2017-01-01

    A new streaming strategy of the LHCb experiment includes the possibility to perform the physics analysis with candidates reconstructed in the trigger, thus bypassing the offline reconstruction. In the Turbo stream the trigger writes out a compact summary of physics objects containing all information necessary for analyses. This allows an increased output rate and thus higher average efficiencies. The Turbo stream was introduced in 2015 and has allowed for and expanded physics program in Run 2 of the LHC.

  8. Measurement of semileptonic asymmetries at LHCb

    CERN Multimedia

    CERN. Geneva

    2014-01-01

    CP violation in neutral B meson mixing is an excellent place to search for the effects of new physics beyond the Standard Model. I report on the first measurements of the CP violating semileptonic asymmetries in the B_s0 and B_d0 systems from LHCb. Both are consistent with the Standard Model expectations and are the most precise single measurements of these parameters to date.

  9. Heavy flavour production and spectroscopy at LHCb

    CERN Document Server

    INSPIRE-00258787

    2012-01-01

    At the Moriond QCD conference LHCb has presented results on heavy flavour production and spectroscopy. Here the latest results are discussed, which include the first observation and measurement of the branching fraction of the hadronic decay $B^+_e \\to J/\\psi\\pi^+ \\pi^- \\pi^+$, the mass measurement of the excited B mesons and the mass measurement of the $\\Xi_b$ and $\\Omega_b$ baryons.

  10. Heavy flavour production and spectroscopy at LHCb

    International Nuclear Information System (INIS)

    Manca, G.

    2014-01-01

    We present recent results in heavy flavour production and spectroscopy from the LHCb experiment, obtained using a data-set corresponding to up to 1 fb -1 of pp collisions at √(s)=7 TeV. We will discuss the studies of production of B mesons and quarkonium states, and the first observation of excited Λ* b states, as well as the production of double charm and χ c states. (author)

  11. New spokesperson for the LHCb collaboration

    CERN Multimedia

    Katarina Anthony

    2011-01-01

    Pierluigi Campana begins his 3-year tenure as LHCb spokesperson this June. As the new voice for the collaboration, Campana will lead the experiment through what should prove to be a very exciting phase.   Pierluigi Campana, from the Istituto Nazionale di Fisica Nucleare in Frascati, has been with the collaboration since 2000 and was heavily involved in the construction of the muon chamber of the LHCb detector. He replaces Andrei Golutvin, from Imperial College London and Russia’s Institute for Theoretical and Experimental Physics. “Leading such a large collaboration is not an easy task,” says Campana. While he will rely heavily upon the work of his predecessor, he plans on leaving his own mark on the position: “One of the main goals of my job will be to enhance the spirit of collaboration between the different institutes within our experiment.” LHCb plays a key role in the search for new physics. The experiment is conducting a very precise search...

  12. DAQ Architecture for the LHCb Upgrade

    International Nuclear Information System (INIS)

    Liu, Guoming; Neufeld, Niko

    2014-01-01

    LHCb will have an upgrade of its detector in 2018. After the upgrade, the LHCb experiment will run at a high luminosity of 2 × 10 33 cm −2 s −1 . The upgraded detector will be read out at 40 MHz with a highly flexible software-based triggering strategy. The Data Acquisition (DAQ) system of LHCb reads out the data fragments from the Front-End Electronics and transports them to the High-Lever Trigger farm at an aggregate throughput of ∼ 32 Tbit/s. The DAQ system will be based on high speed network technologies such as InfiniBand and/or 10/40/100 Gigabit Ethernet. Independent of the network technology, there are different possible architectures for the DAQ system. In this paper, we present our studies on the DAQ architecture, where we analyze size, complexity and relative cost. We evaluate and compare several data-flow schemes for a network-based DAQ: push, pull and push with barrel-shifter traffic shaping. We also discuss the requirements and overall implications of the data-flow schemes on the DAQ system.

  13. 3D Monitoring of LHCb Inner Tracker

    CERN Multimedia

    Sainvitu, Pascal

    2015-01-01

    The positions of the Inner Tracker (IT) detectors of the LHCb experiment installed in the LHC at CERN are impacted by the LHCb dipole magnet powering. In the past the movements of the stations have been measured using standard survey methods during magnet tests in shutdown periods. But the survey targets are visible only in very narrow spaces and the access to the IT is very difficult, even impossible in the central region when the detector is closed. Finally the precision of the standard survey measurement is affected by the poor configuration. In 2013 and 2014, during the first long shutdown of the LHC (LS1), the CERN Survey team (EN/MEF-SU) in collaboration with the LHCb Technical Coordination and the EPFL (Ecole Polytechnique Fédérale de LAUSANNE, CH), developed a permanent monitoring system which has been tested and installed in order to allow the 3D position measurement of the IT stations, even during the run periods, with a precision of 100 microns at 1 sigma level. The 3D Monitoring system of the LH...

  14. LHCb Calorimeter modules arrive at CERN

    CERN Multimedia

    2002-01-01

    Two of the three components of the LHCb Calorimeter system have started to arrive from Russia. Members of the LHCb Calorimeter group with the ECAL and HCAL modules that have just arrived at CERN. The first two of the 56 Hadron Calorimeter (HCAL) modules and 1200 of the 3300 modules of the Electromagnetic Calorimeter (ECAL) have reached CERN from Russia. The third part of the system, the Preshower detector, is still being prepared in Russia. The calorimeter system identifies and triggers on high-energy particles, namely electrons, hadrons and photons by measuring their positions and energies. The HCAL is going to be a pure trigger device. The ECAL will also be used in the triggering, but in addition it will reconstruct neutral pions and photons from B meson decays. One of the major aims of the LHCb experiment is to study CP violation through B meson decays including Bs mesons with high statistics in different decay modes. CP violation (violation of charge and parity) is necessary to explain why the Universe...

  15. LHCb celebrates completion of its beam pipe

    CERN Multimedia

    2007-01-01

    Members of the LHCb collaboration and of the AT and TS Departments are ready to pop open the champagne bottles and celebrate the complete installation and commissioning of the LHCb experiment’s beam pipe. Members of the LHCb collaboration and of the AT and TS Departments gather near the newly completed beam pipe in the foreground. All four sections of LHCb’s beam pipe have been installed, interconnected, pumped down and baked out.. Three of the conical tubes are made of beryllium in order to minimize the level of background in the experiment, while the fourth and largest section is composed of stainless steel. The first of the beryllium sections, an important connection to the Vertex Locator vacuum vessel (VELO) was installed in August 2006 (see Bulletin No. 37/2006). One of the more challenging tasks was the installation of the longest (6 m) piece of beryllium beam pipe through the 2.4 m long RICH2 detector in January 2006. Deli...

  16. Results on LHCb Data Challenge 06

    CERN Document Server

    Santinelli, R

    2007-01-01

    The Large Hadron Collider (LHC) at CERN is the front end machine for the high-energy physics (HEP) and will start operating in 2007. The expected amount of data that will be produced and that has to be analyzed is unprecedented. LHCb, one of the large experiments at the LHC, moved toward grid technologies to cope with their requirements. The integration of the experiment specific computing framework into the underlying production grid has not been always effortless. Grid technologies represent the only way to deal with HEP today’s computing needs. The complexity of these new techniques brought the need of designing, for each experiment, a model for processing and analyzing the data. The 2006 data challenge – LHCb DC06 – is the latest of a series of big activities on the Grid and represents the final benchmark before the real data taking. Its goal is validating the computing model and the computing framework of LHCb but it is also the last opportunity for exercising the whole simulation chain on WLCG res...

  17. LHCb: A novel method for an absolute luminosity measurement at LHCb using beam-gas imaging

    CERN Multimedia

    Barschel, C

    2013-01-01

    A novel technique to measure the absolute luminosity at the Large Hadron Collider (LHC) using beam-gas interactions has been successfully used in the LHCb experiment. A gas injection device (SMOG) has been installed in the LHCb experiment to increase the pressure around the interaction point during dedicated fills. The Beam Gas Imaging method (BGI) has now the potential to surpass the accuracy of the commonly used van der Meer scan method (VDM). This poster presents the principles of the Beam Gas Imaging method used to measure the beam overlap integral. Furthermore the gas injection increased the accuracy measurement of the so-called ghost charges and also intensities per bunch.

  18. LHCb: Measurement of the $\\gamma$ angle from tree decays at LHCb

    CERN Multimedia

    Martín Sánchez, Alexandra

    2011-01-01

    An overview of plans for the measurement of $\\gamma$ at the LHCb experiment will be shown. The $\\gamma$ angle is the parameter of the CKM unitary triangle that is known least well. The LHCb experiment at the CERN LHC aims to perform precision b-physics and CP violation measurements, including improving the knowledge of $\\gamma$. Focus will be put on methods where B mesons decay at the tree level, within the Standard Model framework. The early data recorded by the experiment, from $pp$ collisions at $\\sqrt{s}$ = 7 TeV, has allowed observations of the first signals of the B decay modes that will be used to perform this measurement.

  19. LHCb: Design of a Highly Optimised Vacuum Chamber Support for the LHCb Experiment

    CERN Multimedia

    Leduc, L; Veness, R

    2011-01-01

    The beam vacuum chamber in the LHCb experimental area passes through the centre of a large aperture dipole magnet. The vacuum chamber and all its support systems lie in the acceptance of the detector, so must be highly optimised for transparency to particles. As part of the upgrade programme for the LHCb vacuum system, the support system has been re-designed using advanced lightweight materials. In this paper we discuss the physics motivation for the modifications, the criteria for the selection of materials and tests performed to qualify them for the particular environment of a particle physics experiment. We also present the design of the re-optimised support system.

  20. Calibration of a leak detection spectrometer; Calibration d'un spectrometre detecteur de fuites

    Energy Technology Data Exchange (ETDEWEB)

    Geller, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    This paper describes a study of the possible methods for calibrating a leak detection spectrometer, and the estimation of outputs from the leaks is considered. With this in mind the question of sensitivity of leak detection is tackled on a very general level; first the sensitivity of the isolated instrument is determined, and then the sensitivity of an instrument connected to an installation where leaks may be suspected. Finally, practical solutions are proposed. (author) [French] Dans cet article, nous etudions les methodes possibles de calibration d'un spectrometre detecteur de fuites et nous envisageons l'evaluation des debits de fuites trouves. Pour cela, nous abordons la notion de sensibilite de la detection de fuite sur un plan tres general; d'abord nous determinons la sensibilite de l'appareil isole, ensuite la sensibilite d'un appareil connecte sur une installation ou l'on cherche les fuites. Enfin, nous preconisons des solutions pratiques. (auteur)

  1. Absolute measurement of a standard thermal-neutron flux using gold-detector activation; Mesure absolue d'un flux etalon de neutrons thermiques par activation de detecteurs d'or

    Energy Technology Data Exchange (ETDEWEB)

    Paternot, Y [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1967-02-15

    The density of neutrons in a standard stacking is determined between the zero-energy and the cut-off energy of 1 mm thick cadmium unit using a gold detector. Its absolute activity is measured using a 4 {pi} {beta} counter calibrated for 4 {pi} {beta},{gamma} coincidence by counting strongly active sources. The correction factor F due to the disintegration process for the gold is determined experimentally. {phi}{sub 0} = N{sub 0} {sup E}Cd{sub V0} = 6495 {+-} 1.5 per cent n/cm{sup 2}/s. (author) [French] La densite de neutrons dans un empilement etalon est determinee entre l'energie zero et l'energie de coupure d'un boitier de cadmium de 1 mm d'epaisseur au moyen d'un detecteur d'or. Son activite absolue est mesuree a l'aide d'un compteur 4 {pi} {beta} etalonne en coincidence 4 {pi} {beta},{gamma} par comptage de sources fortement actives. Le facteur de correction F d au schema de desintegration de l'or est determine experimentalement. {phi}{sub 0} = N{sub 0} {sup E}Cd{sub V0} = 6495 {+-} 1.5 pour cent n/cm{sup 2}/s. (auteur)

  2. ARIADNE: a tracking system for relationships in LHCb metadata

    International Nuclear Information System (INIS)

    Shapoval, I; Clemencic, M; Cattaneo, M

    2014-01-01

    The data processing model of the LHCb experiment implies handling of an evolving set of heterogeneous metadata entities and relationships between them. The entities range from software and databases states to architecture specificators and software/data deployment locations. For instance, there is an important relationship between the LHCb Conditions Database (CondDB), which provides versioned, time dependent geometry and conditions data, and the LHCb software, which is the data processing applications (used for simulation, high level triggering, reconstruction and analysis of physics data). The evolution of CondDB and of the LHCb applications is a weakly-homomorphic process. It means that relationships between a CondDB state and LHCb application state may not be preserved across different database and application generations. These issues may lead to various kinds of problems in the LHCb production, varying from unexpected application crashes to incorrect data processing results. In this paper we present Ariadne – a generic metadata relationships tracking system based on the novel NoSQL Neo4j graph database. Its aim is to track and analyze many thousands of evolving relationships for cases such as the one described above, and several others, which would otherwise remain unmanaged and potentially harmful. The highlights of the paper include the system's implementation and management details, infrastructure needed for running it, security issues, first experience of usage in the LHCb production and potential of the system to be applied to a wider set of LHCb tasks.

  3. ARIADNE: a Tracking System for Relationships in LHCb Metadata

    Science.gov (United States)

    Shapoval, I.; Clemencic, M.; Cattaneo, M.

    2014-06-01

    The data processing model of the LHCb experiment implies handling of an evolving set of heterogeneous metadata entities and relationships between them. The entities range from software and databases states to architecture specificators and software/data deployment locations. For instance, there is an important relationship between the LHCb Conditions Database (CondDB), which provides versioned, time dependent geometry and conditions data, and the LHCb software, which is the data processing applications (used for simulation, high level triggering, reconstruction and analysis of physics data). The evolution of CondDB and of the LHCb applications is a weakly-homomorphic process. It means that relationships between a CondDB state and LHCb application state may not be preserved across different database and application generations. These issues may lead to various kinds of problems in the LHCb production, varying from unexpected application crashes to incorrect data processing results. In this paper we present Ariadne - a generic metadata relationships tracking system based on the novel NoSQL Neo4j graph database. Its aim is to track and analyze many thousands of evolving relationships for cases such as the one described above, and several others, which would otherwise remain unmanaged and potentially harmful. The highlights of the paper include the system's implementation and management details, infrastructure needed for running it, security issues, first experience of usage in the LHCb production and potential of the system to be applied to a wider set of LHCb tasks.

  4. Electrical limitations to energy resolution in semiconductor particle detectors; Limitations electriques du pouvoir de resolution en energie des detecteurs a semi-conducteurs; Ehlektricheskie ogranicheniya razreshayushchej sposobnosti po ehnergii v poluprovodnikovykh detektorakh chastits; Limitaciones electricas en la resolucion energetica de detectores de particulas a base de semiconductores

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, W L; Goulding, F S [Lawrence Radiation Laboratory, University of California, Berkeley, CA (United States)

    1962-04-15

    Based on the assumption that the noise contribution of a semiconductor detector is due solely to its bulk properties, equations are presented which indicate the theoretical limits of noise in detectoramplifier combinations. These equations show that an optimum amplifier time-constant and detector bias voltage exist for which condition the minimum noise is independent of the semiconductor resistivity. The optimum performance of a detector-amplifier system is shown to depend only upon detector area, input capacity (less detector capacity), semiconductor minority carrier lifetime and the transconductance of the amplifier input tube. A new detector structure which includes a guard-ring electrode as an integral part of the detector structure is described which has the effect of largely eliminating noise due to surface leakage. Experimental results for detector leakage and energy resolution which agree well with theory are presented. The theoretical limit of noise, expressed as full width at half maximum, is from 7 to 10 keV for 1-cm{sup 2} p-type silicon detectors at 25{sup o}C. (author) [French] Partant de l'hypothese que le bruit imputable au detecteur a semi-conducteur est du exclusivement aux proprietes fondamentales du semi-conducteur, les auteurs etablissent des equations donnant les limites theoriques du bruit dans les combinaisons detecteur-amplificateur. Ces equations montrent qu'il existe une constante de temps optimum de l'amplificateur et une tension de polarisation du detecteur, pour lesquelles le bruit minimum est independant de la resistivite du semi-conducteur. Les auteurs prouvent que l'optimum de fonctionnement d'un ensemble detecteur-amplificateur ne depend que de la surface du detecteur, de la capacite a l'entree (deduction faite de la capacite du detecteur), du porteur minoritaire du semi-conducteur, de la duree de vie et de la transconductance du tube d'entree de l'amplificateur. Ils decrivent un modele nouveau de detecteur qui comprend une

  5. Geant4 hadronic and electromagnetic validation tests in LHCb

    CERN Document Server

    Griffith, Peter Noel

    2016-01-01

    LHCb uses Geant4 to simulate the interactions of particles with the detector material and components. The simulation response can vary significantly due to modification of material description, of detector geometry, or of the Geant4 toolkit itself. Therefore, an extensive variety of tools have been developed to study the effects of Geant4 modification on the LHCb simulation framework and on stand-alone environments within the LHCb software infrastructure. These tools have proven to be very effective for investigating new and alternative models provided by Geant4, and also in identifying and fixing anomalous behaviours that arise from changes. The next goal is to have these validation tests run autonomously and periodically, alerting the relevant users when problems are detected. Quick and easy comparison of the results from different software versions and simulation models will be made possible through the web interface of the LHCb Performance and Regression testing system, LHCbPR.

  6. Upgrade of the monitoring system of LHCb ECAL

    CERN Document Server

    Guz, Iouri; Chernov, Evgeny; Egorychev, Victor; Kandybei, Sergii; Kvaratskheliya, Tengiz; Obraztsov, Vladimir; Perret, Pascal; Philippov, Sergey; Savrina, Daria; Shatalov, Sppavel; Zakoriuchkina, Tatiana; Zhokhov, Anatoli; Zvyagintsev, Serguei

    2016-01-01

    The LHCb ECAL is a shashlik calorimeter of 6016 cells, covering 7.686.24 m2 area. To monitor the readout chain of each ECAL cell, the LHCb ECAL is equipped with a LED based monitoring system. During the LHC Run I (2009-2012) it was found that the precision of the monitoring suffers from the radiation degradation of transparency of polystyrene clear fibers used to transport the LED light to the ECAL photomultipliers. In order to improve the performance of the monitoring system, and especially in view of significant increase of LHCb working luminosity foreseen after 2018, the present plastic fibers have been replaced by radiation hard quartz fibers. The design of the upgraded version of the LHCb ECAL monitoring system is described here. The usage and performance of the new system for the ECAL calibration during the LHCb Run II are discussed.

  7. LHCb: Study of a solution with COTS for the LHCb calorimeter upgrade

    CERN Multimedia

    Abellan Beteta, C

    2011-01-01

    Since the end of the commissioning of LHCb in 2009 the detector has proven to work nicely even in high pile-up conditions and by the end of 2010 nominal instantaneous luminosity was reached. Data taking is expected to continue for 5 more years, aiming to accumulate an integrated luminosity of 5fb-1. Even if new physics is discovered at that time, it will be difficult to characterize it and it would be more profitable to upgrade the detector. The foreseen long shutdown offers an opportunity to upgrade the detector . As expressed in the Letter of Intend for the LHCb upgrade [1] the main objective of this enhancement is to have a 40MHz readout electronics to allow the use of a more flexible and efficient software-based triggering system. Moreover, after the shutdown, the instantaneous luminosity at the LHCb interaction point is expected to be multiplied by 5. From the point of view of the LHCb calorimeter changing the readout implies a change of the electronic boards. Also because of the luminosity increase and ...

  8. LHCb: Quantum Efficiency of Hybrid Photon Detectors for the LHCb RICH

    CERN Multimedia

    Lambert, Robert W

    2007-01-01

    The production of 550 hybrid photon detectors to be used within the LHCb RICH detectors has recently finished. Photonis-DEP have succeeded in consistently improving the tube quantum efficiency, by a relative 27,% with respect to preseries and prototype tubes, when integrated over the energy spectrum.

  9. LHCb: Control and Monitoring of the Online Computer Farm for Offline processing in LHCb

    CERN Multimedia

    Granado Cardoso, L A; Closier, J; Frank, M; Gaspar, C; Jost, B; Liu, G; Neufeld, N; Callot, O

    2013-01-01

    LHCb, one of the 4 experiments at the LHC accelerator at CERN, uses approximately 1500 PCs (averaging 12 cores each) for processing the High Level Trigger (HLT) during physics data taking. During periods when data acquisition is not required most of these PCs are idle. In these periods it is possible to profit from the unused processing capacity to run offline jobs, such as Monte Carlo simulation. The LHCb offline computing environment is based on LHCbDIRAC (Distributed Infrastructure with Remote Agent Control). In LHCbDIRAC, job agents are started on Worker Nodes, pull waiting tasks from the central WMS (Workload Management System) and process them on the available resources. A Control System was developed which is able to launch, control and monitor the job agents for the offline data processing on the HLT Farm. This control system is based on the existing Online System Control infrastructure, the PVSS SCADA and the FSM toolkit. It has been extensively used launching and monitoring 22.000+ agents simultaneo...

  10. LHCb: Ageing Phenomena in the Straw Tube Tracker (Outer Tracker) of the LHCb experiment

    CERN Multimedia

    Bachmann, S

    2009-01-01

    The outer tracking system of the LHCb spectrometer is built in the straw tube technology. In tota it consists of 53760 straw of 2.5m length. Thorough investigations have been performed to study the detector performance under long-term irradiations. Problems occuring caused by ageing are discussed and solutions are presented.

  11. LHCb : Behaviour of Multi-anode Photomultipliers in Magnetic Fields for the LHCb RICH Upgrde

    CERN Multimedia

    Gambetta, Silvia

    2015-01-01

    A key feature of the LHCb upgrade, scheduled for 2019, is to remove the first level trigger and its data reduction from 40MHz to 1MHz, which is implemented in the on-detector readout electronics. The consequence for the LHCb Ring Imaging Cherenkov (RICH) detectors is that the Hybrid Photon Detectors need to be replaced as the readout chip is inside the detector vacuum. The baseline for replacement are Multianode Photomultiplier tubes (MaPMT) and new readout electronics. The MaPMTs will be located in the fringe field of the LHCb dipole magnet with residual fields up to 25 G. Therefore, their behaviour in magnetic fields is critical. Here we report about studies of the Hamamatsu models R11265 and H12700 in a magnetic field in an effort to qualify them for use in the LHCb RICH upgrade. Comparisons to the known model R7600 are also made. Measurements of the collection efficiency and gain were performed for all three space directions as a function of the magnetic field strength. In addition to measurements with ba...

  12. LHCb : Measuring $CP$ violation with $\\Delta A_{CP}$ at LHCb

    CERN Multimedia

    Pearce, A

    2014-01-01

    Measurements are presented of direct $CP$ violation in $D^{0}$ meson decays in LHCb, using the $\\Delta A_{CP}$ technique, and a proposal is outlined to make similar measurements in the decays of the charmed baryon $\\Lambda_{c}^{+}$. The motivations for use of the $\\Delta A_{CP}$ method are discussed, along with the current results and future prospects.

  13. LHCb: Statistical Comparison of CPU performance for LHCb applications on the Grid

    CERN Multimedia

    Graciani, R

    2009-01-01

    The usage of CPU resources by LHCb on the Grid id dominated by two different applications: Gauss and Brunel. Gauss the application doing the Monte Carlo simulation of proton-proton collisions. Brunel is the application responsible for the reconstruction of the signals recorded by the detector converting them into objects that can be used for later physics analysis of the data (tracks, clusters,…) Both applications are based on the Gaudi and LHCb software frameworks. Gauss uses Pythia and Geant as underlying libraries for the simulation of the collision and the later passage of the generated particles through the LHCb detector. While Brunel makes use of LHCb specific code to process the data from each sub-detector. Both applications are CPU bound. Large Monte Carlo productions or data reconstructions running on the Grid are an ideal benchmark to compare the performance of the different CPU models for each case. Since the processed events are only statistically comparable, only statistical comparison of the...

  14. LHCb: Measurement of polarisation amplitudes and triple product asymmetries in the $B_s^0 \\to \\phi \\phi$ decay at LHCb

    CERN Multimedia

    Benson, Sean

    2012-01-01

    An untagged, time-integrated analysis of the $B_s^0 \\to \\phi \\phi$ decay has been performed with 1 fb$^{-1}$ of $pp$ collision data at centre-of-mass (COM) energy $\\sqrt{s} = 7$ TeV taken using the LHCb detector. Optimised selections have yielded 801 $B_s^0 \\to \\phi \\phi$ events at high signal to background ratio. This has allowed for measurements of polarisation amplitudes ($|A_0|^2$, $|A_{\\perp}|^2$, $|A_{\\parallel}|^2$) and strong phase difference (cos$\\delta_{\\parallel}$) to be performed. Measurements of $T$-violating triple product asymmetries have yielded results $A_U = ^- 0.055 \\pm 0.036 (stat.) \\pm 0.018 (syst.)$ & $A_V = 0.010 \\pm 0.036 (stat.) \\pm 0.018 (syst.)$.

  15. Fixed-target physics at LHCb

    CERN Document Server

    Maurice, Emilie Amandine

    2017-01-01

    The LHCb experiment has the unique possibility, among the LHC experiments, to be operated in fixed target mode, using its internal gas target SMOG. The energy scale achievable at the LHC and the excellent detector capabilities for vertexing, tracking and particle identification allow a wealth of measurements of great interest for cosmic ray and heavy ions physics. We report the first measurements made in this configuration: the measurement of antiproton production in proton-helium collisions and the measurements of open and hidden charm production in proton-argon collisions at $\\sqrt{s_\\textrm{NN}} =$ 110 GeV.

  16. Observation of double charm production at LHCb

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    The production of J/ψ together with an open charm meson, and double open charm production are observed in proton-proton collisions at centre-of-mass energy of 7 TeV using an integrated luminosity of 355 pb−1 collected with the LHCb detector. Model independent estimates of absolute cross-sections are given together with ratios to the measured J/ψ and open charm cross-sections. The properties of these events are studied and compared to theoretical predictions.

  17. Searches for lepton flavour violation at LHCb

    CERN Multimedia

    CERN. Geneva

    2013-01-01

    Charged lepton flavour is conserved within the Standard Model (SM) up to exceedingly small rates of about $10^{-50}$. This makes charged lepton flavour violation (cLFV) a very interesting place to look for hints of New Physics (NP). In fact, many NP scenarios predict cLFV to occur at rates within the reach of the experiments. Finding these transitions would mean a definite departure from the SM, while not finding them narrows the NP phase space. In this seminar, the latest LHCb results in the cLFV sector will be presented, and their implications for NP scenarios discussed.

  18. Performance of the LHCb Vertex Locator

    CERN Document Server

    Bjørnstad, Pal Marius

    2011-01-01

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

  19. A GPU offloading mechanism for LHCb

    International Nuclear Information System (INIS)

    Badalov, Alexey; Cardona, Xavier Vilasis; Perez, Daniel Hugo Campora; Zvyagin, Alexander; Neufeld, Niko

    2014-01-01

    The current computational infrastructure at LHCb is designed for sequential execution. It is possible to make use of modern multi-core machines by using multi-threaded algorithms and running multiple instances in parallel, but there is no way to make efficient use of specialized massively parallel hardware, such as graphical processing units and Intel Xeon/Phi. We extend the current infrastructure with an out-of-process computational server able to gather data from multiple instances and process them in large batches.

  20. Luminosity Measurements at LHCb for Run II

    CERN Multimedia

    Coombs, George

    2018-01-01

    A precise measurement of the luminosity is a necessary component of many physics analyses, especially cross-section measurements. At LHCb two different direct measurement methods are used to determine the luminosity: the “van der Meer scan” (VDM) and the “Beam Gas Imaging” (BGI) methods. A combined result from these two methods gave a precision of less than 2% for Run I and efforts are ongoing to provide a similar result for Run II. Fixed target luminosity is determined with an indirect method based on the single electron scattering cross-section.

  1. Trigger tracking for the LHCb upgrade

    CERN Multimedia

    Dungs, K

    2014-01-01

    This poster presents a trigger system for the upgraded LHCb detector, scheduled to begin operation in 2020. The proposed trigger system is implemented entirely in software. We show that track reconstruction of a similar quality to that available in the offline algorithms can be performed on the full inelastic pp-collision rate. A track finding efficiency of 98.8% relative to offline can be achieved for good trigger tracks. The CPU time required for this reconstruction is less than 60% of the available budget.

  2. Constraining CKM $\\gamma$ angle at LHCb

    CERN Document Server

    Vallier, Alexis Roger Louis

    2015-01-01

    The current combination of all available tree-level measurements of the CKM angle gamma at LHCb is reported. It includes results obtained from time independent analyses of B+ -> DK+ and of B0 -> DK∗0 decays; and from a time-dependent analysis of Bs0 -> DsK decays. The results represent the world's best single-experiment determination of gamma. The first observation of the Bs->Ds*K decay and the first observation and amplitude analysis of B- -> D+K-pi- are also reported. In addition to these tree measurements, the estimation of gamma from charmless B meson decay, sensitive to loops contribution, is presented.

  3. Test of lepton flavour universality at LHCb

    CERN Document Server

    Lionetto, Federica

    2016-01-01

    This contribution presents the $R_D{\\ast}$ and $R_K$ measurements, which are a clean probe of lepton flavour universality, and the angular analyses of the $B^0 \\to K^\\ast {0} \\mu^+ \\mu^-$ and $B^0 \\to K^\\ast{0} ~e^+ e^-$ decays, which allow to search for New Physics in rare decays proceeding through ${\\text a} ~b \\to s \\ell^+ \\ell^-$ transition. All measurements have been performed by the LHCb collaboration using the full statistics of LHC Run I. An overview of the ongoing and future measurements is given in the conclusions.

  4. Optimizing the Stripping Procedure for LHCb

    CERN Document Server

    Richardson, Rachel

    2017-01-01

    The LHCb experiment faces a major challenge from the large amounts of data received while the LHC is running. The ability to sort this information in a useful manner is important for working groups to perform physics analyses. Both hardware and software triggers are used to decrease the data rate and then the stripping process is used to sort the data into streams and further into stripping lines. This project studies the hundreds of stripping lines to look for overlaps between them in order to make the stripping process more efficient.

  5. LHCb: Measuring B to mu mu K

    CERN Document Server

    De Cian, M

    2009-01-01

    The Flavour Changing Neutral Current decay B to mu mu K, which only occurs via loop processes in the SM, is sensitive to contributions from a variety of possible new physics sources. LHCb, the dedicated b physics experiment at the LHC, will record an unprecedented number of B to mu mu K decays, allowing precision measurements of a large number of variables, which will provide evidence or place constraints for physics beyond the SM. This poster gives a short overview of the detector, introduces some of these variables and presents a selection for B to mu mu K.

  6. Results of Soft-Diffraction at LHCb

    CERN Document Server

    Meissner, Marco

    2013-01-01

    The LHCb detector with its unique pseudorapidity coverage allows to perform soft-QCD measurements in the kinematic forward region where QCD models have large uncertainties. Selected analyses related to soft-Diffraction will be summarised in these proceedings. Energy flow and charged particle multiplicity have been measured separately in different event classes. They give input for modelling the underlying event in $pp$ collisions. Prompt hadron ratios are important for hadronisation models, while the $p/p$ ratio is a good observable to test models of baryon number transport.

  7. Tests of lepton flavour universality at LHCb

    CERN Document Server

    Lupato, Anna

    2018-01-01

    In the Standard Model the electroweak coupling of the gauge bosons to leptons is independent of the lepton flavour. Semileptonic and rare decays of b quarks provide an ideal laboratory to test this property. Any violation of Lepton Flavour Universality would be a clear sign of physics beyond the Standard Model. In this work a review of the Lepton Flavour Universality tests performed using data collected by the LHCb experiment in 2011 and 2012 at a centre of mass energy of 7 and 8 TeV is presented.

  8. The LHCb trigger in Run II

    CERN Document Server

    Michielin, Emanuele

    2016-01-01

    The LHCb trigger system has been upgraded to allow alignment, calibration and physics analysis to be performed in real time. An increased CPU capacity and improvements in the software have allowed lifetime unbiased selections of beauty and charm decays in the high level trigger. Thanks to offline quality event reconstruction already available online, physics analyses can be performed directly on this information and for the majority of charm physics selections a reduced event format can be written out. Beauty hadron decays are more efficiently triggered by re-optimised inclusive selections, and the HLT2 output event rate is increased by a factor of three.

  9. Cosmics in the LHCb Outer Tracker

    CERN Document Server

    Aaij, Roel

    2010-01-01

    The LHCb experiment at the Large Hadron Collider studies the decay of B mesons to test the description of CP violation in the Standard Model and to search for new physics. The decay $B_s \\to \\mu^+ \\mu^-$ has been identified as very promising in the search for new physics. An excellent invariant mass resolution is required to suppress backgrounds to this decay. This in turn requires a momentum resolution of dp/p = 0.4%. The Outer Tracker is part of the LHCb tracking system and has been commissioned with cosmic muons. The noise in the Outer Tracker is shown to be less than 0.05%. To use drift time information in the reconstruction of cosmic tracks, the event time must be known. Four methods to obtain the event time are studied and compared. It is shown that the event time can be obtained with a resolution better than 2.6 ns. Using drift time information, tracks are reconstructed with a resolution of 344 $\\mu$m. Knowledge of the event time enables the calibration of electronic time offsets and the r(t)– relati...

  10. Developments towards the LHCb VELO upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Cid Vidal, Xabier, E-mail: xabier.cid.vidal@cern.ch

    2016-09-21

    The Vertex Locator (VELO) is a silicon strip detector surrounding the interaction region of the LHCb experiment. The upgrade of the VELO is planned to be installed in 2019–2020, and the current detector will be replaced by a hybrid pixel system equipped with electronics capable of reading out at a rate of 40 MHz. The new detector is designed to withstand the radiation dose expected at an integrated luminosity of 50 fb{sup −1}. The detector will be composed of silicon pixel sensors, read out by the VeloPix ASIC that is being developed based on the TimePix/MediPix family. The prototype sensors for the VELO upgrade are being irradiated in five different facilities and the post-irradiation performance is being measured with testbeams, and in the lab. These proceedings present the VELO upgrade and briefly discuss the results of the sensor testing campaign. - Highlights: • The VELO is the detector surrounding the LHCb collision point. • After its upgrade, the VELO will be capable of reading out at a rate of 40 MHz. • The detector will be composed of Si pixel sensors, read out by the VeloPix ASIC. • The irradiated prototype sensors for the VELO upgrade are currently being tested.

  11. Rare beauty and charm decays at LHCb

    CERN Document Server

    INSPIRE-00261996

    2012-01-01

    New results are presented using a data sample with an integrated luminosity of $∼ 1 fb^{−1}$ collected in 2011 with the LHCb detector. The B → $µ^+ µ^−$ and $D^0 → µ^+ µ^−$ results have been presented at a previous conference. The angular distributions and (partial) branching fractions of selected radiative penguin decays are studied using a data sample with an integrated luminosity of ∼ 1$fb^{−1}$ collected in 2011 with the LHCb detector. The partial branching fraction and theoretically clean observables of the decay $B^0 → K^{∗0} µ^+ µ^−$ have been extracted as a function of the dimuon invariant mass. The partial branching fraction of the decay $B^0_s$ → $φµ^+ µ^−$ has also been extracted as a function of the dimuon invariant mass. The branching fraction and first observation of the decay $B^+$ → $π^+ µ^+ µ^−$ is reported. New limits were set on the decay $B → µ^+ µ^− µ^+ µ^−$. Improved limits on the decays $B → µ^+ µ^−$ and $D^0 → µ^+ µ^−$ are...

  12. COTS Analog Prototype for LHCb's Calorimeter Upgrade

    CERN Document Server

    Abellan Beteta, Carlos; Herms i Berenguer, Atilà

    The objective of this thesis is to present a proposal for the analogue signal processing chain needed for the LHCb calorimeter upgrade improving the design used originally. The design contains several novelties: the system was designed with low noise in mind from the beginning, it is made to have good immunity to interferences stressing the fact that the board will be shared with large digital circuits, differential operational amplifiers are used in a non-standard way as a mean to obtain opposite polarity signals for the signal treatment and a way to increase the available signal in the front end electronics is proposed. The thesis starts with a brief introduction to the detector and its environment. This is followed by an explanation of the use of shapers in high energy physics detectors and the constraints that the shaper must address in the LHCb calorimeter. This leads to a chapter where the circuit design is explained starting from the analysis of the original circuit and its flaws. Once the original cir...

  13. The LHCb trigger and data acquisition system

    CERN Document Server

    Dufey, J P; Harris, F; Harvey, J; Jost, B; Mato, P; Müller, E

    2000-01-01

    The LHCb experiment is the most recently approved of the 4 experiments under construction at CERNs LHC accelerator. It is a special purpose experiment designed to precisely measure the CP violation parameters in the B-B system. Triggering poses special problems since the interesting events containing B-mesons are immersed in a large background of inelastic p-p reactions. We therefore decided to implement a 4 level triggering scheme. The LHCb Data Acquisition (DAQ) system will have to cope with an average trigger rate of ~40 kHz, after two levels of hardware triggers, and an average event size of ~100 kB. Thus an event-building network which can sustain an average bandwidth of 4 GB/s is required. A powerful software trigger farm will have to be installed to reduce the rate from the 40 kHz to ~100 Hz of events written to permanent storage. In this paper we outline the general architecture of the Trigger and DAQ system and the readout protocols we plan to implement. First results of simulations of the behavior o...

  14. Preliminary studies for the LHCb vertex detector vacuum system

    CERN Document Server

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

    2000-01-01

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

  15. Design and performances of the LHCb Muon System

    CERN Multimedia

    Campana, P

    2009-01-01

    We present the detector design and performance of the LHCb Muon System. In order to fulfill the requirements of the experiment, the chambers have to provide high detection efficiency, a good time resolution, a high rate capability and good aging characteristics. We present performance results of the chambers from beam tests, with cosmics rays and at the CERN Gamma Irradiation Facility. Cosmic rays have also been used to study the performance of the chambers in the experimental setup. The obtained results allow us to conclude that the requirements of the LHCb experiment are fulfilled and that the LHCb Muon detector is ready for data taking.

  16. The LHCb Silicon Tracker - Control system specific tools and challenges

    CERN Document Server

    Adeva, G; Esperante Pereira, D; Gallas, A; Pazos Alvarez, A; Perez Trigo, E; Rodriguez Perez, P; Saborido, J; Amhis, Y; Bay, A; Blanc, F; Bressieux, J; Conti, G; Dupertuis, F; Fave, V; Frei, R; Gauvin, N; Haefeli, G; Keune, A; Luisier, J; Marki, R; Muresan, R; Nakada, T; Needham, M; Knecht, M; Schneider, O; Tran, M; Anderson, J; Buechler, A; Bursche, A; Chiapolini, N; De Cian, M; Elsasser, C; Salzmann, C; Saornil Gamarra, S; Steiner, S; Steinkamp, O; Straumann, U; van Tilburg, J; Tobin, M; Vollhardt, A; Aquines Gutierrez, O; Bauer, C; Britsch, M; Maciuc, F; Schmelling, M; Voss, H; Iakovenko, V; Okhrimenko, O; Pugatch, V

    2014-01-01

    The Experiment Control System (ECS) of the LHCb Silicon Tracker sub-detectors is built on the integrated LHCb ECS framework. Although all LHCb sub-detectors use the same framework and follow the same guidelines, the Silicon Tracker control system uses some interesting additional features in terms of operation and monitoring. The main details are described in this document. Since its design, the Silicon Tracker control system has been continuously evolving in a quite disorganized way. Some major maintenance activities are required to be able to keep improving. A description of those activities can also be found here.

  17. LHCb - A SciFi production center in NRC KI FOR LHCb upgrade

    CERN Multimedia

    Shevchenko, Vladimir

    2015-01-01

    The Scintillating Fiber Tracker, SciFi for short, will be the main new tracking detector in LHCb. It will provide better than 100 µm spatial resolution, and high rate capability and radiation hardness enabling a fast, 40 MHz, trigger rate with a capability to withstand 50 fb$^{-1}$ integrated luminosity, delivered by LHC, without a major performance degradation. The main active element of the tracker is a scintillating fiber ribbon with the SiPM readout. The ribbons consist of 6 layers of the 250 µm scintillating fibers Kuraray SCSF-78MJ, assembled by winding and bound together by the epoxy glue. NRC Kurchatov Institute, Moscow, together with the colleagues from ITEP, CERN, TU of Dortmund and RWTH of Aachen are developing dedicated production centers with the aim to reach by 2016 production rate one ribbon per day per center, necessary to supply more than 1300 fibre ribbons (mats) needed for the new LHCb tracker.

  18. LHCb: Optimising query execution time in LHCb Bookkeeping System using partition pruning and partition wise joins

    CERN Multimedia

    Mathe, Z

    2013-01-01

    The LHCb experiment produces a huge amount of data which has associated metadata such as run number, data taking condition (detector status when the data was taken), simulation condition, etc. The data are stored in files, replicated on the Computing Grid around the world. The LHCb Bookkeeping System provides methods for retrieving datasets based on their metadata. The metadata is stored in a hybrid database model, which is a mixture of Relational and Hierarchical database models and is based on the Oracle Relational Database Management System (RDBMS). The database access has to be reliable and fast. In order to achieve a high timing performance, the tables are partitioned and the queries are executed in parallel. When we store large amounts of data the partition pruning is essential for database performance, because it reduces the amount of data retrieved from the disk and optimises the resource utilisation. This research presented here is focusing on the extended composite partitioning strategy such as rang...

  19. LHCb: Detector Module Design, Construction and Performance for the LHCb SciFi Tracker

    CERN Multimedia

    Ekelhof, R

    2014-01-01

    The Scintillating Fibre (SciFi) Tracker for the LHCb Upgrade (CERN/LHCC 2014-001; LHCb TDR 15) is based on 2.5 m long multi-layered ribbons from 10,000 km of scintillating fibre over 12 planes covering 350 m2. The planes are separated into modular detectors, each with cooled silicon photomultiplier (SiPM) arrays for photo-readout. In this talk, we will present the construction and performance of this novel detector, including the intricacies of scintillating fibre ribbon production, constructing precision detector planes with a rigid and light module design, and the integration of the readout components for this detector. The complexities and issues regarding this active part of the SciFi Tracker will be emphasised along with the current solutions and measured performances.

  20. LHCb: Performance of the fourgap LHCb Muon Chambers tested with cosmic rays

    CERN Document Server

    Pinci, D

    2007-01-01

    The LHCb Muon System is composed of five detection stations (M1M5)mainly equipped with a total of 1368 MultiWire Proportional Chambers (MWPC). MWPCs need to ensure a high detection efficiency, a fast response and a good space resolution. We present here the results of detailed studies of the performance of different fourgap chambers, completely equipped with the final FrontEnd Electronics, measured with cosmic rays. Aspects such as time resolution, hit multiplicity and time and space structure of the crosstalk hits were measured. For the first time, both types of chambers, those with anodewirereadout and those with cathodepadreadout, were tested and the results are compared. Results hereby obtained will be used to individuate the optimal working conditions of the apparatus and to achieve a more realistic detector description in the LHCb Monte Carlo simulation.

  1. LHCb : First years of running for the LHCb calorimeter system and preparation for run 2

    CERN Multimedia

    Chefdeville, Maximilien

    2015-01-01

    The LHCb experiment is dedicated to precision measurements of CP violation and rare decays of B hadrons at the Large Hadron Collider (LHC) at CERN (Geneva). It comprises a calorimeter system composed of four subdetectors: a Scintillating Pad Detector (SPD) and a Pre-Shower detector (PS) in front of an electromagnetic calorimeter (ECAL) which is followed by a hadron calorimeter (HCAL). They are used to select transverse energy hadron, electron and photon candidates for the first trigger level and they provides the identification of electrons, photons and hadrons as well as the measurement of their energies and positions. The calorimeter has been pre-calibrated before its installation in the pit. The calibration techniques have been tested with data taken in 2010 and used regularly during run 1. For run 2, new calibration methods have been devised to follow and correct online the calorimeter detector response. The design and construction characteristics of the LHCb calorimeter will be recalled. Strategies for...

  2. LHCb: First observation of $B^+ \\to \\pi^+ \\mu^+ \\mu -$ with LHCb

    CERN Multimedia

    Ciezarek, Gregory

    2012-01-01

    A search for the decay $B^+ \\to \\pi^+ \\mu^+ \\mu^-$ is presented using 1.0 fb$^{-1}$ of pp collision data integrated luminosity collected with the LHCb experiment at the Large Hadron Collider during 2011. This decay is observed for the first time with 5.2 $\\sigma$ significance, at a branching fraction BR$(B^+ \\to \\pi^+ \\mu^+ \\mu^-) = (2.4 \\pm 0.6 \\rm{(stat)} \\pm 0.2 \\rm{(syst)}) \\times 10^{-8}$.

  3. LHCb: Probing photon polarization in Bs->phi gamma decay at LHCb

    CERN Multimedia

    Shchutska, L

    2008-01-01

    The radiative decay Bs->phi gamma is one of the benchmark channels in the physics programme of the LHCb experiment. It provides the possibility to test the Standard Model through the indirect measurement of the photon polarization in b->s gamma transition. The statistical uncertainty in the wrong polarization fraction of photons is estimated to be ~0.2 with the 2 fb^{-1} of integrated luminosity.

  4. LHCb: Measurement of $J/\\psi$ production cross-section at LHCb

    CERN Multimedia

    Zhang, Y

    2011-01-01

    The measurement of the $J/\\psi$ production cross-section with the LHCb detector is presented. The cross-section is measured as a function of the $J/\\psi$ transverse momentum and rapidity, in the forward region. Contributions from prompt $J/\\psi$ and $J/\\psi$ from $b$ are measured separately. Prospects for measurements of the $J/\\psi$ polarisation with a full angular analysis are also shown.

  5. LHCb: Measuring $CP$ Violation in $\\Lambda_{c}^{+}$ Decays at LHCb

    CERN Multimedia

    Pearce, A

    2013-01-01

    An ongoing analysis of a measurement of CP violation in decays of the charmed baryon $\\Lambda_{c}^{+}$, using the full $3\\mathrm{fb}^{-1}$ of data collected by LHCb in 2011 and 2012, is presented. The detection asymmetry of the final states is considered, leading to the use of the narrow $p\\phi$ and $pK_{s}^{0}$ resonances in the $pK^{+}K^{-}$ and $p\\pi^{+}\\pi^{-}$ phase spaces, respectively.

  6. LHCb: The LHCb Silicon Tracker - Control system specific tools and challenges

    CERN Multimedia

    Saornil Gamarra, S

    2013-01-01

    The experiment control system of the LHCb experiment is continuously evolving and improving. The guidelines and structure initially defined are kept, and more common tools are made available to all sub-detectors. Although the main system control is mostly integrated and actions are executed in common for the whole LHCb experiment, there is some degree of freedom for each sub-system to implement the control system using these tools or by creating new ones. The implementation of the LHCb Silicon Tracker control system was extremely disorganized and with little documentation. This was due to either lack of time and manpower, and/or to limited experience and specifications. Despite this, the Silicon Tracker control system has behaved well during the first LHC run. It has continuously evolved since the start of operation and been adapted to the needs of operators with very different degrees of expertise. However, improvements and corrections have been made on a best effort basis due to time constraints placed by t...

  7. LHCb Distributed Data Analysis on the Computing Grid

    CERN Document Server

    Paterson, S; Parkes, C

    2006-01-01

    LHCb is one of the four Large Hadron Collider (LHC) experiments based at CERN, the European Organisation for Nuclear Research. The LHC experiments will start taking an unprecedented amount of data when they come online in 2007. Since no single institute has the compute resources to handle this data, resources must be pooled to form the Grid. Where the Internet has made it possible to share information stored on computers across the world, Grid computing aims to provide access to computing power and storage capacity on geographically distributed systems. LHCb software applications must work seamlessly on the Grid allowing users to efficiently access distributed compute resources. It is essential to the success of the LHCb experiment that physicists can access data from the detector, stored in many heterogeneous systems, to perform distributed data analysis. This thesis describes the work performed to enable distributed data analysis for the LHCb experiment on the LHC Computing Grid.

  8. The mechanical Design of the LHCb Silicon Trigger Tracker

    CERN Document Server

    Gassner, J; Steiner, S

    2010-01-01

    In this note, we describe the design of the Silicon Trigger Tracker for the LHCb experiment. We emphasize on detector module and station design and characterize the layout of all relevant parts and components.

  9. Past, Present and Future of the LHCb Detector

    CERN Document Server

    Cogoni, Violetta

    2016-01-01

    The LHCb experiment has been designed as a high precision experiment devoted to the search of physics beyond the Standard Model through the study of CP violation and rare decays in hadrons containing b and c quarks. During the Run 1 of LHC, the LHCb detector has performed very well producing a large number of physics results on a vast number of subjects. The first Long Shutdown offered the opportunity to further optimise the detector, anticipating in some cases the interventions foreseen for Run 3. Nevertheless, the phase of upgrade of the detector, foreseen for 2019–2020, will be crucial to exploit the full potential of the LHCb experiment. In this context, an overview of the LHCb detector is presented, concerning its past, present, and foreseen future performances

  10. Proposal for the LHCb outer tracker front-end electronics

    CERN Document Server

    Deppe, H; Feuerstack-Raible, M; Srowig, A; Stange, U; Hommels, B; Sluijk, T

    2001-01-01

    A market survey on available TDCs for reading out the LHCb Outer Tracker has left over only one TDC, which is not optimal for this purpose. Hence, a new readout architecture which is based on a TDC to be developed anew has been defined. This system fits optimal the requirements of the LHCb Outer Tracker and also should be much cheaper. The system and its main issues are described in this paper.

  11. Developments for the outer tracking system of the LHCb experiment

    CERN Document Server

    Bachmann, S; Haas, T; Uwer, U; Walter, M; Wiedner, D

    2004-01-01

    The outer tracking system of the LHCb experiment is discussed. The outer tracking system (OT) is made of three stations and every station is made up of four detecting planes with a double layer of straw tubes. The straw tubes are mounted in detector module boxes made up of sandwich panels. The use of a counting gas with a high drift velocity is suggested to cope with high bunch crossing rate at the LHCb experiment. (Edited abstract) 3 Refs.

  12. CP violation in the B and D systems at LHCb

    CERN Document Server

    Romero Vidal, A

    2014-01-01

    The large samples of mesons containing a $b$ or a $c$ quark collected by the LHCb experiment in 2011 and 2012, corresponding to an integrated luminosity of 3 fb$^{-1}$, provide an unprecedent framework to perform high precision measurements of CP violation. A comparison of measurements of CP violating observables with the Standard Model predictions can reveal contributions from physics beyond the Standard Model. Studies of $B$ and $D$ meson decays at LHCb are presented in this document.

  13. Studies of W and Z production with the LHCb experiment

    CERN Document Server

    Shears, T G

    2009-01-01

    We report on studies of W and Z production with the LHCb experiment. Due to its acceptance, LHCb can probe a regime of low Bjorken x electroweak boson production, where parton distribution functions are not well constrained. In this review strategies for triggering, selection and background rejection are discussed, and studies of the sensitivity of differential cross-section measurements to the underlying parton density functions presented.

  14. LHCb Particle Identification Strategy and Performance in Run 2

    CERN Multimedia

    Tilley, Matthew James

    2018-01-01

    For Run 2 of LHCb data taking, the selection of PID calibration samples is implemented in the high level trigger. A further processing is needed to provide calibration samples used for the determination the PID performance, which is achieved through a centralised production that makes highly efficient use of LHCb computing resources. This poster presents the major steps of the production procedure and the charged particle PID performance measured using these calibration samples.

  15. Jagiellonian University Development of the LHCb VELO monitoring software platform

    CERN Document Server

    Majewski, Maciej

    2017-01-01

    One of the most important parts of the LHCb spectrometer is the VErtex LOcator (VELO), dedicated to the precise tracking close to the proton–proton interaction point. The quality of data produced by the VELO depends on the calibration process, which must be monitored to ensure its correctness. This work presents details on how the calibration monitoring is conducted and how it could be improved. It also includes information on monitoring software and data flow in the LHCb software framework.

  16. TELL1: development of a common readout board for LHCb

    International Nuclear Information System (INIS)

    Legger, Federica; Bay, Aurelio; Haefeli, Guido; Locatelli, Laurent

    2004-01-01

    LHCb is one of the four experiments currently under construction at LHC (Large Hadron Collider) at CERN, and its aim is the study of b-quark physics (LHCb Collaboration, CERN-LHCC/98-4). LHCb trigger strategy is based on three levels, and will reduce the event rate from 40 MHz to a few hundred Hz (LHCb Collaboration, CERN/LHCC 2003-031, LHCb TDR 10, September 2003). The first two levels (L0 and L1) will use signals from some part of the detector in order to take fast decisions, while the last one, called High Level Trigger (HLT), will have access to the full event data. An 'off detector' readout board (TELL1) has been developed and will be used by the majority of LHCb subdetectors. It takes L0 accepted data as input and, after data processing which includes event synchronization, L1 Trigger pre-processing and zero suppression, L1 buffering, and HLT zero suppression, the output is sent to L1 Trigger and HLT

  17. Performance of the LHCb Outer Tracker

    CERN Document Server

    Arink, R; Bachmann, S.; Bagaturia, Y.; Band, H.; Bauer, Th.; Berkien, A.; Farber, Ch.; Bien, A.; Blouw, J.; Ceelie, L.; Coco, V.; Deckenhoff, M.; Deng, Z.; Dettori, F.; van Eijk, D.; Ekelhof, R.; Gersabeck, E.; Grillo, L.; Hulsbergen, W.D.; Karbach, T.M.; Koopman, R.; Kozlinskiy, A.; Langenbruch, Ch.; Lavrentyev, V.; Linn, Ch.; Merk, M.; Merkel, J.; Meissner, M.; Michalowski, J.; Morawski, P.; Nawrot, A.; Nedos, M.; Pellegrino, A.; Polok, G.; van Petten, O.; Rovekamp, J.; Schimmel, F.; Schuylenburg, H.; Schwemmer, R.; Seyfert, P.; Serra, N.; Sluijk, T.; Spaan, B.; Spelt, J.; Storaci, B.; Szczekowski, M.; Swientek, S.; Tolk, S.; Tuning, N.; Uwer, U.; Wiedner, D.; Witek, M.; Zeng, M.; Zwart, A.

    2014-01-01

    The LHCb Outer Tracker is a gaseous detector covering an area of 5x6 m2 with 12 double layers of straw tubes. The detector with its services are described together with the commissioning and calibration procedures. Based on data of the first LHC running period from 2010 to 2012, the performance of the readout electronics and the single hit resolution and efficiency are presented. The efficiency to detect a hit in the central half of the straw is estimated to be 99.2%, and the position resolution is determined to be approximately 200 um. The Outer Tracker received a dose in the hottest region corresponding to 0.12 C/cm, and no signs of gain deterioration or other ageing effects are observed.

  18. Charmless B-decays at LHCb

    CERN Document Server

    Eklund, Lars

    2016-01-01

    These proceedings summarise three recent papers from the LHCb Collaboration in the area of charmless b-decays. The branching fraction for the decay $\\text{B}_{s}^{0}\\rightarrow \\phi \\phi$ is measured and a search for the highly suppressed decay $\\text{B}^{0}\\rightarrow \\phi \\phi$ is performed. The decay $\\text{B}_{s}^{0}\\rightarrow {\\eta}'{\\eta}'$ is observed for the first time and the CP asymmetries in the decays $\\text{B}^{+}\\rightarrow {\\eta}'\\text{K}^{+}$ and $\\text{B}^{+}\\rightarrow \\phi \\text{K}^{+}$ are measured. Finally, the decay $\\text{B}^{0}\\rightarrow \\rho^{0}\\rho^{0}$ is observed for the first time and its longitudinal polarisation is measured.

  19. Ageing of the LHCb outer tracker

    CERN Document Server

    Blom, M R; Tuning, N

    2009-01-01

    The modules of the LHCb outer tracker have shown to suffer severe gain loss under moderate irradiation. This process is called ageing. Ageing of the modules results from contamination of the gas system by glue, araldite AY 103-1, used in their construction. In this thesis the ageing process will be shown. The schemes known to reduce, reverse, or prevent ageing have been investigated to determine their effect on the detector performance. The addition of O2 to the gas mixture lowers the detector response by an acceptable amount and does not affect the gas transport properties significantly. The ageing rate is decreased after extensive flushing and HV training could eventually repair the irradiation damage. The risks of HV training have been assessed. Furthermore, several gaseous and aquatic additions have been tested for their capability to prevent, or moderate ageing, but none showed significant improvement.

  20. LHCb: Monitoring the DIRAC Distribution System

    CERN Multimedia

    Nandakumar, R; Santinelli, R

    2009-01-01

    DIRAC is the LHCb gateway to any computing grid infrastructure (currently supporting WLCG) and is intended to reliably run large data mining activities. The DIRAC system consists of various services (which wait to be contacted to perform actions) and agents (which carry out periodic activities) to direct jobs as required. An important part of ensuring the reliability of the infrastructure is the monitoring and logging of these DIRAC distributed systems. The monitoring is done collecting information from two sources - one is from pinging the services or by keeping track of the regular heartbeats of the agents, and the other from the analysis of the error messages generated by both agents and services and collected by the logging system. This allows us to ensure that he components are running properly and to collect useful information regarding their operations. The process status monitoring is displayed using the SLS sensor mechanism which also automatically allows one to plot various quantities and also keep ...

  1. A Universal Logging System for LHCb Online

    International Nuclear Information System (INIS)

    Nikolaidis, Fotis; Brarda, Loic; Garnier, Jean-Christophe; Neufeld, Niko

    2011-01-01

    A log is recording of system's activity, aimed to help system administrator to traceback an attack, find the causes of a malfunction and generally with troubleshooting. The fact that logs are the only information an administrator may have for an incident, makes logging system a crucial part of an IT infrastructure. In large scale infrastructures, such as LHCb Online, where quite a few GB of logs are produced daily, it is impossible for a human to review all of these logs. Moreover, a great percentage of them as just n oise . That makes clear that a more automated and sophisticated approach is needed. In this paper, we present a low-cost centralized logging system which allow us to do in-depth analysis of every log.

  2. LHCb: Pilot Framework and the DIRAC WMS

    CERN Multimedia

    Graciani, R; Casajus, A

    2009-01-01

    DIRAC, the LHCb community Grid solution, has pioneered the use of pilot jobs in the Grid. Pilot jobs provide a homogeneous interface to an heterogeneous set of computing resources. At the same time, pilot jobs allow to delay the scheduling decision to the last moment, thus taking into account the precise running conditions at the resource and last moment requests to the system. The DIRAC Workload Management System provides one single scheduling mechanism for jobs with very different profiles. To achieve an overall optimisation, it organizes pending jobs in task queues, both for individual users and production activities. Task queues are created with jobs having similar requirements. Following the VO policy a priority is assigned to each task queue. Pilot submission and subsequent job matching are based on these priorities following a statistical approach. Details of the implementation and the security aspects of this framework will be discussed.

  3. LHCb: Numerical Analysis of Machine Background in the LHCb Experiment for the Early and Nominal Operation of LHC

    CERN Multimedia

    Lieng, M H; Corti, G; Talanov, V

    2010-01-01

    We consider the formation of machine background induced by proton losses in the long straight section of the LHCb experiment at LHC. Both sources showering from the tertiary collimators located in the LHCb insertion region as well as local beam-gas interaction are taken into account. We present the procedure for, and results of, numerical studies of such background for various conditions. Additionally expected impact and on the experiment and signal characteristics are discussed.

  4. Low-$p_T$ dimuon triggers at LHCb in Run 2

    CERN Document Server

    Dettori, Francesco; Prisciandaro, Jessica

    2017-01-01

    The LHCb trigger efficiency for strange hadron decays to final states containing dimuon pairs was substantially improved for Run 2 of the LHC. This note describes the updated strategy, and its impact on the LHCb rare strange physics programme.

  5. Behaviour of semiconductor nuclear-particle detectors; Comportement des semi-conducteurs comme detecteurs de particules nucleaires; Povedenie detektorov yadernykh chastits na poluprovodnikakh; Propiedades de los detectores de particulas nucleares a base de semiconductores

    Energy Technology Data Exchange (ETDEWEB)

    Walter, F J; Dabbs, J W.T.; Roberts, L D [Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    1962-04-15

    . Matched expansion-coefficient fabrication techniques which have been successfully used to make detectors up to 8 cm{sup 2} in active area are also described. (author) [French] Les auteurs ont fait des etudes theoriques et experimentales sur le comportement des semi-conducteurs comme detecteurs de particules nucleaires a des temperatures allant de 0,2{sup o} K a 300{sup o} K. Ils presentent un modele theorique simple du comportement du detecteur qui correspond au comportement observe pour toute une gamme de valeurs des parametres. Ils examinent quelle est l'importance de la purete du semi-conducteur et de la tension de polarisation en ce qui concerne l'amplitude de l'impulsion, le temps de montee de l'impulsion et la surface du detecteur. Des etudes empiriques sur le bruit et la resolution en energie montrent que, pour des particules alpha, les plus petites largeurs de crete observees sont tres nettement plus importantes que les largeurs que l'on avait prevues en tenant compte du bruit d'origine electrique provenant du detecteur et de l'amplificateur. A 77{sup o}K, on a releve pour un detecteur a barriere de surface au silicium, d'une surface de 40 mm{sup 2}, des intensites de bruit equivalant a {<=} 3 keV (largeur totale a mi-hauteur du maximum). Les semi-conducteurs presentent un a l'egard des fragments de fission. On a tout lieu de penser que ce defaut n'est pas du a une . Si des champs electriques insuffisants pour assurer une complete sont la cause de ce defaut, le gradient de champ necessaire (a la surface) est superieur a 3 {center_dot} 10{sup 4} V/cm dans le cas de fragments de fission contre 2 {center_dot} 10{sup 3} V/cm dans le cas de particules alpha de Ge et de Si. Des etudes detaillees sur le temps de montee des impulsions au niveau de l'amplificateur ont montre que pour des substances de grande resistivite le temps de relaxation dielectrique et la resistance propres aux substances de base non appauvries peuvent

  6. Detector for the liquid carried over in a gas; Detecteur d'entrainement de liquide dans un gaz

    Energy Technology Data Exchange (ETDEWEB)

    Delisle, J P; Eperonnat, P; Lions, N [Commissariat a l' Energie Atomique, Cadarache (France). Centre d' Etudes Nucleaires

    1965-07-01

    This report describes an optical detector for the detection of a liquid carried over by a gas. The device is sensitive to a cumulated quantity of liquid equal to a few cubic millimetres and is capable of operating an alarm from a distance. The prototype was constructed and tested as detector for the oil leaking in the argon compressed by a diaphragm compressor. A patent for this apparatus under the number: P.V.954.703, has been deposited on 22.11.1963. (authors) [French] Ce rapport decrit un detecteur optique d'entrainement de liquide dans un gaz, sensible a une quantite cumulee de liquide entraine egale a quelques millimetres cubes. L'appareil peut actionner une alarme a distance. Le prototype a ete construit et essaye comme detecteur de fuites d'huile dans l'argon refoule par un compresseur a membranes. Une demande de brevet a ete deposee pour cet appareil sous le numero: P.V.954.703, le 22.11.1963. (auteur)

  7. Development of ultracold neutron detectors and a polarization analyzing system for the measurement of the neutron electric dipole moment; Developpement de detecteurs de neutrons ultra-froids et d'un systeme d'analyse de polarisation pour la mesure du moment electrique dipolaire du neutron

    Energy Technology Data Exchange (ETDEWEB)

    Rogel, Gwendal

    2009-10-29

    This thesis was performed in the context of a project aiming to measure the electric dipole moment (EDM) of the neutron at the Paul Scherrer Institute. Two aspects have been studied: The detection and the polarization analysis of ultracold neutrons. Three types of detectors have been tested at the Institut Laue-Langevin (ILL): The Cascade-U (GEM technology), the {sup 3}He gas detector and {sup 6}Li-doped glass scintillators (GS family). Their detection efficiency and their background sensitivity have been measured. The GS10 scintillator is competitive with the {sup 3}He gas detector under the conditions realized with the EDM spectrometer. A GS3/GS20 scintillator stack has enabled to improve the neutron/gamma discrimination. It has been found 20% less efficient than the {sup 3}He gas detector under the EDM spectrometer. The Cascade-U detector has been observed to be 20% less efficient than a 500 microns thick GS10 glass as confirmed by simulations. A new system for simultaneous spin analysis is presented. It consists of two independent detection systems (arms) which are each made of an adiabatic spin flipper, a spin analyzer, and a detector. The arms detect opposite spin components, allowing the simultaneous counting of both neutron spin orientations. A prototype mounted in horizontal configuration has been tested at ILL. The analyzing power of both arms has been measured to be 80%. The transmission of the system without spin analyzers has been found to be 50%. (author) [French] Cette these s'inscrit dans un nouveau projet de mesure du moment dipolaire electrique (EDM) du neutron a l'institut Paul Scherrer. Deux aspects ont ete etudies ici: la detection et l'analyse de polarisation de neutrons ultra-froids. Trois types de detecteurs ont ete testes a l'Institut Laue-Langevin (ILL): le Cascade-U (technologie GEM), le compteur a gaz {sup 3}He et des scintillateurs dopes au {sup 6}Li (type GS). Leur efficacite de detection ainsi que leur sensibilite au bruit de fond ont

  8. LHCb: Test Station for the LHCb Muon Front-End Electronic

    CERN Multimedia

    Polycarpo, E

    2005-01-01

    The LHCb Muon Group has developed the CMOS ASIC CARIOCA to readout its Multiwire Proportional Chambers (MWPC) and GEM detectors, using a rad-hard IBM 0.25um process. Each ASIC holds 8 identical current-mode ASDB channels with individual input thresholds. The Muon detector contains around 120000 physical channels, requiring production of 20000 front-end chips, roughly. CARIOCA has been developed to process MWPC cathode and anode signals and two different versions have been implemented to overcome the requirement of MWP and GEM chambers operation. The test station has been devised to accomplish bipolar tests and to measure characteristics of both CARIOCA versions.

  9. LHCb : Measurement of the $B_c$ Lifetime in semileptonic decays at LHCb

    CERN Multimedia

    Anderlini, Lucio

    2014-01-01

    The lifetime of the $B_c^+$ meson is measured using semileptonic decays having a $J\\!/\\!\\psi$ meson and a muon in the final state. The data, corresponding to an integrated luminosity of $2\\mathrm{fb^{-1}}$, are collected by the LHCb detector in $pp$ collisions at a centre-of-mass energy of $8\\,\\mathrm{TeV}$. The measured lifetime is $$\\tau = 509 \\pm 8 \\pm 12 \\mathrm{~fs},$$ where the first uncertainty is statistical and the second is systematic.

  10. LHCb : Clock and timing distribution in the LHCb upgraded detector and readout system

    CERN Multimedia

    Alessio, Federico; Barros Marin, M; Cachemiche, JP; Hachon, F; Jacobsson, Richard; Wyllie, Ken

    2014-01-01

    The LHCb experiment is upgrading part of its detector and the entire readout system towards a full 40 MHz readout system in order to run between five and ten times its initial design luminosity and increase its trigger efficiency. In this paper, the new timing, trigger and control distribution system for such an upgrade is reviewed with particular attention given to the distribution of the clock and timing information across the entire readout system, up to the FE and the on-detector electronics. Current ideas are here presented in terms of reliability, jitter, complexity and implementation.

  11. LHCb: Observation of CP violation in $B^{\\pm} \\to DK^{\\pm}$ decays at LHCb

    CERN Multimedia

    Gandini, Paolo

    2012-01-01

    An analysis of $B^+ \\to DK^+$ and $B^+ \\to D\\pi^+$ decays is presented where the D meson is reconstructed in the two-body final states: $K^+\\pi-, K^+K^-, \\pi^+\\pi^-$ and $\\pi^+K^-$. Using 1.0 fb$^{-1}$ of LHCb data, measurements of several observables are made including the first observation of the suppressed mode $B^+ \\to DK^+, D \\to \\pi^+K^-$. CP violation in $B^+ \\to DK^+$ decays is observed with 5.8 $\\sigma$ significance.

  12. LHCb - SALT, a dedicated readout chip for strip detectors in the LHCb Upgrade experiment

    CERN Multimedia

    Swientek, Krzysztof Piotr

    2015-01-01

    Silicon strip detectors in the upgraded Tracker of LHCb experiment will require a new readout 128-channel ASIC called SALT. It will extract and digitise analogue signals from the sensor, perform digital processing and transmit serial output data. SALT is designed in CMOS 130 nm process and uses a novel architecture comprising of analogue front-end and ultra-low power ($<$0.5 mW) fast (40 MSps) sampling 6-bit ADC in each channel. A prototype of first 8-channel version of SALT chip, comprising all important functionalities, was submitted. Its design and possibly first tests results will be presented.

  13. LHCb detector and trigger performance in Run II

    Science.gov (United States)

    Francesca, Dordei

    2017-12-01

    The LHCb detector is a forward spectrometer at the LHC, designed to perform high precision studies of b- and c- hadrons. In Run II of the LHC, a new scheme for the software trigger at LHCb allows splitting the triggering of events into two stages, giving room to perform the alignment and calibration in real time. In the novel detector alignment and calibration strategy for Run II, data collected at the start of the fill are processed in a few minutes and used to update the alignment, while the calibration constants are evaluated for each run. This allows identical constants to be used in the online and offline reconstruction, thus improving the correlation between triggered and offline selected events. The required computing time constraints are met thanks to a new dedicated framework using the multi-core farm infrastructure for the trigger. The larger timing budget, available in the trigger, allows to perform the same track reconstruction online and offline. This enables LHCb to achieve the best reconstruction performance already in the trigger, and allows physics analyses to be performed directly on the data produced by the trigger reconstruction. The novel real-time processing strategy at LHCb is discussed from both the technical and operational point of view. The overall performance of the LHCb detector on the data of Run II is presented as well.

  14. Protons on ions bring new physics to LHCb

    CERN Multimedia

    Antonella Del Rosso

    2013-01-01

    The research opportunities offered by proton-lead collisions at the LHC are generating increasing interest among theorists and experimentalists. During this recent run, LHCb, the asymmetric detector originally designed to study CP asymmetries and rare decays involving heavy quarks, took data with proton and ion beams for the first time. Using these collisions, the experiment can provide a different perspective on specific physics processes, so new developments may be in sight.   A proton-lead ion collision observed by the LHCb detector during the 2013 data taking period. LHCb is a smaller detector than the gigantic multi-purpose CMS and ATLAS detectors. It is also smaller than ALICE, the detector designed in particular to study ion-ion collisions. However, LHCb has something special: it can study physics processes that involve particles scattered from collisions at very small angles and close to the collision point. LHCb does not take data during ion-ion r...

  15. Federating LHCb datasets using the DIRAC File catalog

    CERN Document Server

    Haen, Christophe; Frank, Markus; Tsaregorodtsev, Andrei

    2015-01-01

    In the distributed computing model of LHCb the File Catalog (FC) is a central component that keeps track of each file and replica stored on the Grid. It is federating the LHCb data files in a logical namespace used by all LHCb applications. As a replica catalog, it is used for brokering jobs to sites where their input data is meant to be present, but also by jobs for finding alternative replicas if necessary. The LCG File Catalog (LFC) used originally by LHCb and other experiments is now being retired and needs to be replaced. The DIRAC File Catalog (DFC) was developed within the framework of the DIRAC Project and presented during CHEP 2012. From the technical point of view, the code powering the DFC follows an Aspect oriented programming (AOP): each type of entity that is manipulated by the DFC (Users, Files, Replicas, etc) is treated as a separate 'concern' in the AOP terminology. Hence, the database schema can also be adapted to the needs of a Virtual Organization. LHCb opted for a highly tuned MySQL datab...

  16. New LHCb Management readies for run 2 challenges

    CERN Multimedia

    Antonella Del Rosso

    2014-01-01

    As of 1 July, LHCb, one of the four biggest experiments at the LHC, will have a new Management. Ahead are the huge challenges of run 2 and the following long technical shutdown during which LHCb will undergo a major upgrade. In the meantime, the discovery of new physics could be a dream within reach…   New LHCb Spokesperson, Guy Wilkinson.   “We have to make sure that the detector wakes up after its long hibernation and goes back to data taking in the most efficient way and that we are able to process all these data to produce high-quality physics results,” says Guy Wilkinson, new Spokesperson of the LHCb collaboration. Although this already sounds like a considerable “to-do” list for the coming months, it’s just the beginning of a much longer and ambitious plan. “The previous management has done an excellent job in analysing the data we took during run 1. They also put on a very sound footing the LHCb upgrade, whi...

  17. LHCb : LHCbVELO: Performance and Radiation Damage in LHC Run I and Preparationfor Run II

    CERN Multimedia

    Szumlak, Tomasz

    2015-01-01

    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 um thick half-disc silicon sensors with R-measuring and Phi-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 um 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 x 10...

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

    CERN Multimedia

    Carvalho Akiba, K

    2014-01-01

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

  19. LHCb : Performance of the LHCb tracking system in Run I of the LHC

    CERN Multimedia

    Davis, Adam

    2015-01-01

    The LHCb tracking system consists of a Vertex Locator around the interaction point, a tracking station with four layers of silicon strip detectors in front of the magnet, and three tracking stations, using either straw-tubes or silicon strip detectors, behind the magnet. This system allows to reconstruct charged particles with a high efficiency (typically > 95% for particles with momentum > 5 GeV) and an excellent momentum resolution (0.5% for particles with momentum mu mu. Furthermore an optimal decay time resolution is an essential element in the studies of time dependent CP violation. Thanks to the excellent performance of the tracking system, a decay time resolution of ~50 fs is obtained, allowing to resolve the fast B0s oscillation with a mixing frequency of 17.7 ps-1. In this talk, we will give an overview of the track reconstruction in LHCb and review its performance in Run I of the LHC. We will highlight the challenges and improvements of the track reconstruction for the data taking period from 2015 ...

  20. The LHCb VELO Status and Upgrade Developments

    CERN Document Server

    Bates, A G

    2006-01-01

    The LHCb VErtex LOcator (VELO) is a silicon based vertexing sub-detector which has active silicon positioned only 8~mm from the LHC beams and will operate in an extreme (up to 1.3~x~10$^{14}$~1~MeV neutron equivalents~/~cm$^2$~/~year) and non-uniform radiation environment. The complex design of the VELO silicon sensors exploits oxygenated silicon and n$^+$-on-n technology. Research has been carried out into new materials which could significantly extend the lifetime of silicon detectors at the LHC, these would have particular application in a VELO upgrade. Promising new results on the first test beam of a large, high resistivity Czochralski silicon detector with 50 $\\mu$m pitch and 40~MHz electronics will be presented. The performance was studied before and after irradiation with high energy protons. A signal to noise of over 20~:~1 was obtained from the detector and after a fluence of 4.3~x~10$^{14}$~1~MeV~n$_{eq}$ significant charge collection efficiencies were measured at relatively modest voltages. Studie...

  1. First Results from the LHCb Vertex Locator

    CERN Multimedia

    Borghi, S

    2010-01-01

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

  2. Radiative decays of B mesons at LHCb

    CERN Document Server

    Soomro, Fatima; Golutvin, Andrei

    2011-01-01

    This thesis is dedicated to the study of radiative decays of $B$ mesons at LHC$b$. At quark level, such decays are a $b\\to s\\gamma$ transition and take place via a penguin loop and are sensitive to virtual contribution of New Physics, which can be indicated by an increase in the decay rates. These decays also offer the possibility to test the V-A structure of the Standard Model coupling in the processes mediated by loop penguin diagrams. In the decay $B_s \\to \\phi\\gamma$, New Physics contribution can be probed by measuring the polarization of the photon in this decay. Systematic effects in the proper time reconstruction of the $B_s$ in $B_s \\to \\phi\\gamma$ can bias the photon polarization measurement in this decay, which will reduce the sensitivity on the relevant New Physics parameter. The author studied those effects and developed ideas to calibrate them using $B_d\\to K^{*}\\gamma$ and $B_s\\to J/\\psi\\phi$ decays as control channels. These studies are mostly Monte Carlo based due to a relatively small data ...

  3. Observation of charm mixing at LHCb

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    Meson-antimeson mixing has been observed in the K0−K0bar, B0−B0bar and B0s−B0sbar systems. Evidence of mixing in the charm system has been reported by three experiments using different D0 decay channels, but only the combination of these results provides confirmation of D0−D0bar mixing with more than 5σ significance. We report a measurement of charm mixing using the time-dependent ratio of D0 → K+π− to D0 → K−π+ decay rates in D∗+-tagged events reconstructed in 1.0 fb−1 of integrated luminosity recorded by the LHCb experiment in 2011. We measure the mixing parameters x'2 = (−0.9 ± 1.3) × 10−4, y' = (7.2 ± 2.4) × 10−3 and the ratio of doubly-Cabibbo-suppressed to Cabibbo-favored decay rates RD = (3.52 ± 0.15) × 10−3. The result excludes the no-mixing hypothesis with a probability corresponding to 9.1σ and represents the first observation of D0−D0bar oscillations from a single measurement.

  4. LHCb Online Log Analysis and Maintenance System

    CERN Document Server

    Garnier, J-C

    2011-01-01

    History has shown, many times computer logs are the only information an administrator may have for an incident, which could be caused either by a malfunction or an attack. Due to the huge amount of logs that are produced from large-scale IT infrastructures, such as LHCb Online, critical information may be overlooked or simply be drowned in a sea of other messages. This clearly demonstrates the need for an automatic system for long-term maintenance and real time analysis of the logs. We have constructed a low cost, fault tolerant centralized logging system which is able to do in-depth analysis and cross-correlation of every log. This system is capable of handling O(10000) different log sources and numerous formats, while trying to keep the overhead as low as possible. It provides log gathering and management, Offline analysis and online analysis. We call Offline analysis the procedure of analyzing old logs for critical information, while Online analysis refer to the procedure of early alerting and reacting. ...

  5. Performance of the LHCb Vertex Locator

    CERN Document Server

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

    2014-01-01

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

  6. SCI implementation study for LHCb data acquisition

    CERN Document Server

    Müller, H

    1998-01-01

    This paper proposes the use of SCI 1 as a scalable standard to implement the eventbuilder network between the Readout-Units and the Subfarm Controllers of LHCb. SCI [Ref 1] allows for a memory bus-like interconnection between the data sources and the CPU farm, this implies that sources can directly write data to event-buffers in the farm. This data-driven eventbuilding is enhanced by DMA engines as part of the SCI adapters at the source buffers. In general, data may be either written from the sources (event driven DMA for the full readout) or pulled from the destination (demand-driven DMA for the phased readout). A mixture of both readout architectures is possible, a second level push and a third level pull scheme could simultaneously coexist across the same physical network. Sources and destinations are interconnected via very high bandwidth SCI rings ( 4-8 Gbit/s). By using SCI switches, bandwidth scaling up to any required throughput is possible. The functionalities of a Readout Unit (RU) and a Subfarm Con...

  7. Charmless Hadronic Beauty Decays at LHCb

    Directory of Open Access Journals (Sweden)

    Williams Timothy

    2017-01-01

    Full Text Available A summary of six LHCb results on the topic of charmless hadronic b-hadron decays is presented. These are comprised of: a search for the decay Bs0→Ks0K+K− and updated branching fraction measurements of B(s0→Ks0h+h′− decays (h=K,π [1]; the first observation of the decays B0→pp¯π+π−,  Bs0→pp¯K+K−,Bs0→pp¯K+π− and strong evidence for the decay B0→pp¯K+K− [2]; the first observation of the decay Bs0→pΛ¯K− [3]; a search for the decay Bs0→φη′ [4]; the first observation of the decay Ξb−→pK−K− [5] and evidence for CP-violation in Λb0→pπ−π+π− decays [6].

  8. LHCb: Beam and Background Monitoring and the Development of an Online Condition Analysis Tool for the LHCb Experiment at CERN

    CERN Multimedia

    Alessio, F

    2010-01-01

    The LHCb experiment has been taking data since more than half a year at the LHC, recording events from collisions at the highest energy ever achieved. For its physics purposes in the sector of CP violation, the experiment will record data with the best precision achievable. An online and offline beam and background monitoring became therefore essential to understand the performance of the LHC accelerator at CERN, to monitor and study the behavior of the background around the LHCb experiment and to optimize the experimental conditions. During my second year as a Doctoral Student at CERN, I have been working on the timing and readout control as well as on the online Beam, Background, and Luminosity Monitoring of the LHCb experiment in the frame of the LHCb Online group. The group is responsible for the complete data acquisition of the LHCb experiment, from the Front-End Electronics (FEE) to the storage of the data for offline analysis, including the Timing and Fast Control (TFC) system. The latter controls and...

  9. The LHCb VeLo for Phase 1 upgrade

    CERN Document Server

    Dean, Cameron

    2016-01-01

    Large Hadron Collider beauty (LHCb) is a dedicated experiment for studying b and c hadrons at the Large Hadron Collider (LHC). LHCb uses a silicon-strip detector, the Vertex Locator (VELO), for high precision tracking of collisions from the LHC. During Long Shutdown 2 (LS2) of the LHC, the LHCb collaboration will upgrade the detector, switching from the current VELO, ca- pable of a 1 MHz readout, to a hybrid pixel detector capable of reading out at the full bunch crossing rate of the LHC. Substantial progress has been made in the development of the new de- tector. The status of the silicon sensors, custom designed VeloPix ASIC and electronic system will be discussed in detail. The current status of the cooling system and RF foil will also be presented.

  10. Quality Assurance Tests of the LHCb VELO Modules

    CERN Document Server

    Marinho, Franciole

    2007-01-01

    The LHCb experiment has a dedicated vertex detector (VELO) to measure the particle’s tracks close to the interaction point. This paper describes the main steps of the quality assurance tests performed during assembly, reception and installation of the LHCb VELO modules. Visual inspection, electrical tests, thermal tests and metrology measurements were made. A burn-in test of the modules was performed in a vacuum environment similar to that of the LHCb experiment. The signal to noise of the sensors was estimated to be 20.4 3.0 for R sensors and 22.4 3 0 for Φ sensors. The modules were tested up to 350 V and the leakage current of the modules did not exceed 20µA at any stage of the testing. Only 0.6% of channels were found to be noisy or not fully functional. The acceptable operating pressures of the modules in vacuum was also evaluated.

  11. Performance study of hybrid photon detectors for the LHCb RICH

    CERN Document Server

    Kanaya, N; Gys, Thierry; Piedigrossi, D; Wyllie, K

    2005-01-01

    The LHCb experiment is designed to study CP violation and rare phenomena of B mesons with very high accuracy. The LHCb RICH detectors are essential for positive kaon identification, and several strict demands are required of its photon detectors to achieve excellent particle identification performance. In particular, they should have good single photon sensitivity for visible and UV wavelengths and large coverage with fine granularity. HPDs have been developed to meet these requirements in collaboration with industry. They have now been chosen as the photon detector for LHCb, and pre-series tubes are under test prior to mass production. At the same time, more detailed studies are on-going to understand more deeply their characteristics. The result of various performance tests of these tubes as well as the fraction of light reflection in the HPD are described in this paper.

  12. Will LHCb run in the HL-LHC era?

    International Nuclear Information System (INIS)

    Schmidt, B.

    2012-01-01

    The LHCb collaboration presented a Letter of Intent to the LHCC in March 2011 for upgrading the detector during LS2 (2018) and intends to collect a data sample of 50 fb -1 in the LHC and HL-LHC eras. The physics case and the strategy for the upgrade have been endorsed by the LHCC. This paper presents briefly the physics motivations for the LHCb upgrade and the proposed changes to the detector and trigger. In the following part machine related issues for the LHCb upgrade are discussed, in particular issues in relation to the Target Absorber for Secondaries (TAS), Radiation to Electronics (R2E), β* and crossing angle in IP8. (author)

  13. The LHCb VeLo for Phase 1 upgrade

    CERN Document Server

    Dean, Cameron

    2017-01-01

    Large Hadron Collider beauty (LHCb) is a dedicated experiment for studying b and c hadrons at the Large Hadron Collider (LHC). LHCb uses a silicon-strip detector, the Vertex Locator (VELO), for high precision tracking of collisions from the LHC. During Long Shutdown 2 (LS2) of the LHC, the LHCb collaboration will upgrade the detector, switching from the current VELO, ca- pable of a 1 MHz readout, to a hybrid pixel detector capable of reading out at the full bunch crossing rate of the LHC. Substantial progress has been made in the development of the new de- tector. The status of the silicon sensors, custom designed VeloPix ASIC and electronic system will be discussed in detail. The current status of the cooling system and RF foil will also be presented.

  14. Fixed target measurements at LHCb for cosmic rays physics

    CERN Document Server

    AUTHOR|(CDS)2069608

    2018-01-01

    The LHCb experiment has the unique possibility, among the LHC experiments, to be operated in fixed target mode, using its internal gas target. The energy scale achievable at the LHC, combined with the LHCb forward geometry and detector capabilities, allow to explore particle production in a wide Bjorken-$x$ range at the $\\sqrt {s_{NN}} ~$ ~ 100 GeV energy scale, providing novel inputs to nuclear and cosmic ray physics. The first measurement of antiproton production in collisions of LHC protons on helium nuclei at rest is presented. The knowledge of this cross-section is of great importance for the study of the cosmic antiproton flux, and the LHCb results are expected to improve the interpretation of the recent high-precision measurements of cosmic antiprotons performed by the space-borne PAMELA and AMS-02 experiments.

  15. Looking for New Physics: Prospects for B Physics at LHCb

    CERN Document Server

    Uwer, Ulrich

    2009-01-01

    With the startup of LlICb, the dedicated heavy flavor experiment at the LHC, the next round of precision B-experiments will be launched. LHCb has access to about $10^{12}$ B meson decays per year. allowing significant mcasurcmel)ts of even very rare B decays and, in particular, the precision study of the $B_s$ system. With the measurement of rates, angular distributions and CP asymmetries of loop suppressed B decays, LHCb will probe the quantum corrections predicted by the Standard Model. Many observables show a large sensitivity to New Physics contributions. In the following the expected LHCb physics performance and the potential to search for New Physics is discussed for a set of key measurements.

  16. From the CERN web: LHCb, ATLAS, ILC and more

    CERN Multimedia

    2015-01-01

    This new section highlights articles, blog posts and press releases published in the CERN web environment over the past weeks. This way, you won’t miss a thing...     LHCb sees small deviations from the lepton universality 1 September – LHCb collaboration The LHCb experiment at CERN has made the first measurement at a hadron collider of B meson decays that have already shown small deviations from the predictions of the Standard Model in earlier studies at an electron-positron collider. Continue to read…     The figure shows the density of allowed supersymmetric models before and after the ATLAS Run 1 searches. The missing points have been ruled out by the LHC data. The x-axis shows the mass of the supersymmetric dark matter particle, while the y-axis shows the predicted density of those particles in the universe.     ATLAS is narrowing down the theoretical candidates for dark matter 25 August – ATLAS collab...

  17. B-physics prospects with the LHCb experiment

    International Nuclear Information System (INIS)

    Harnew, N.

    2008-01-01

    This paper summarizes the B-physics prospects of the LHCb experiment. Firstly, a brief introduction to the CKM matrix and the mechanism of CP violation in the Standard Model is given. The advantages of the LHCb experiment for B-physics exploitation will then be described, together with a short description of the detector components. Finally, the LHCb physics aims and prospects will be summarized, focusing on the measurements of sin(2β) in tree and gluonic penguin diagrams, sin(2α) in B d 0 → π + π - and π + π - π 0 , neutral B-meson oscillations and the B s 0 mixing phase, and the measurement of γ using a variety of complementary methods

  18. Integration of Cloud resources in the LHCb Distributed Computing

    CERN Document Server

    Ubeda Garcia, Mario; Stagni, Federico; Cabarrou, Baptiste; Rauschmayr, Nathalie; Charpentier, Philippe; Closier, Joel

    2014-01-01

    This contribution describes how Cloud resources have been integrated in the LHCb Distributed Computing. LHCb is using its specific Dirac extension (LHCbDirac) as an interware for its Distributed Computing. So far, it was seamlessly integrating Grid resources and Computer clusters. The cloud extension of DIRAC (VMDIRAC) allows the integration of Cloud computing infrastructures. It is able to interact with multiple types of infrastructures in commercial and institutional clouds, supported by multiple interfaces (Amazon EC2, OpenNebula, OpenStack and CloudStack) – instantiates, monitors and manages Virtual Machines running on this aggregation of Cloud resources. Moreover, specifications for institutional Cloud resources proposed by Worldwide LHC Computing Grid (WLCG), mainly by the High Energy Physics Unix Information Exchange (HEPiX) group, have been taken into account. Several initiatives and computing resource providers in the eScience environment have already deployed IaaS in production during 2013. Keepin...

  19. VeloTT tracking for LHCb Run II

    CERN Document Server

    Bowen, Espen Eie; Tresch, Marco

    2016-01-01

    This note describes track reconstruction in the LHCb tracking system upstream of the magnet, combining VELO tracks with hits in the TT sub-detector. The implementation of the VeloTT algorithm and its performance in terms of track reconstruction efficiency, ghost rate and execution time are presented. The algorithm has been rewritten for use in the first software trigger level for LHCb Run II. The momentum and charge information obtained for the VeloTT tracks (due to a fringe magnetic field between the VELO and TT sub-detectors) can reduce the total execution time for the full tracking sequence.

  20. Measurement of the track reconstruction efficiency at LHCb

    CERN Document Server

    Aaij, Roel; Adinolfi, Marco; Affolder, Anthony; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Anderson, Jonathan; Andreassen, Rolf; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Aquines Gutierrez, Osvaldo; Archilli, Flavio; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Batozskaya, Varvara; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Belogurov, Sergey; Belous, Konstantin; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bien, Alexander; Bifani, Simone; Bird, Thomas; Bizzeti, Andrea; Bjørnstad, Pål Marius; Blake, Thomas; Blanc, Frédéric; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borghi, Silvia; Borgia, Alessandra; Borsato, Martino; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Brambach, Tobias; van den Brand, Johannes; Bressieux, Joël; Brett, David; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Brook, Nicholas; Brown, Henry; Bursche, Albert; Busetto, Giovanni; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Campana, Pierluigi; Campora Perez, Daniel; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Chen, Shanzhen; Cheung, Shu-Faye; Chiapolini, Nicola; Chrzaszcz, Marcin; Ciba, Krzystof; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coco, Victor; Cogan, Julien; Cogneras, Eric; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombes, Matthew; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Counts, Ian; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Dalseno, Jeremy; David, Pascal; David, Pieter; Davis, Adam; De Bruyn, Kristof; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Silva, Weeraddana; De Simone, Patrizia; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Déléage, Nicolas; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Di Canto, Angelo; Dijkstra, Hans; Donleavy, Stephanie; Dordei, Francesca; Dorigo, Mirco; Dosil Suárez, Alvaro; Dossett, David; Dovbnya, Anatoliy; Dreimanis, Karlis; Dujany, Giulio; Dupertuis, Frederic; Durante, Paolo; Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; Easo, Sajan; Egede, Ulrik; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; El Rifai, Ibrahim; Elsasser, Christian; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Färber, Christian; Farinelli, Chiara; Farley, Nathanael; Farry, Stephen; Fay, Robert; Ferguson, Dianne; Fernandez Albor, Victor; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fiore, Marco; Fiorini, Massimiliano; Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fontana, Marianna; Fontanelli, Flavio; Forty, Roger; Francisco, Oscar; Frank, Markus; Frei, Christoph; Frosini, Maddalena; Fu, Jinlin; Furfaro, Emiliano; Gallas Torreira, Abraham; Galli, Domenico; Gallorini, Stefano; Gambetta, Silvia; Gandelman, Miriam; Gandini, Paolo; Gao, Yuanning; García Pardiñas, Julián; Garofoli, Justin; Garra Tico, Jordi; Garrido, Lluis; Gaspar, Clara; Gauld, Rhorry; Gavardi, Laura; Gavrilov, Gennadii; Gersabeck, Evelina; Gersabeck, Marco; Gershon, Timothy; Ghez, Philippe; Gianelle, Alessio; Giani', Sebastiana; Gibson, Valerie; Giubega, Lavinia-Helena; Gligorov, V.V.; Göbel, Carla; Golubkov, Dmitry; Golutvin, Andrey; Gomes, Alvaro; Gotti, Claudio; Grabalosa Gándara, Marc; Graciani Diaz, Ricardo; Granado Cardoso, Luis Alberto; Graugés, Eugeni; Graziani, Giacomo; Grecu, Alexandru; Greening, Edward; Gregson, Sam; Griffith, Peter; Grillo, Lucia; Grünberg, Oliver; Gui, Bin; Gushchin, Evgeny; Guz, Yury; Gys, Thierry; Hadjivasiliou, Christos; Haefeli, Guido; Haen, Christophe; Haines, Susan; Hall, Samuel; Hamilton, Brian; Hampson, Thomas; Han, Xiaoxue; Hansmann-Menzemer, Stephanie; Harnew, Neville; Harnew, Samuel; Harrison, Jonathan; He, Jibo; Head, Timothy; Heijne, Veerle; Hennessy, Karol; Henrard, Pierre; Henry, Louis; Hernando Morata, Jose Angel; van Herwijnen, Eric; Heß, Miriam; Hicheur, Adlène; Hill, Donal; Hoballah, Mostafa; Hombach, Christoph; Hulsbergen, Wouter; Hunt, Philip; Hussain, Nazim; Hutchcroft, David; Hynds, Daniel; Idzik, Marek; Ilten, Philip; Jacobsson, Richard; Jaeger, Andreas; Jalocha, Pawel; Jans, Eddy; Jaton, Pierre; Jawahery, Abolhassan; Jing, Fanfan; John, Malcolm; Johnson, Daniel; Jones, Christopher; Joram, Christian; Jost, Beat; Jurik, Nathan; Kaballo, Michael; Kandybei, Sergii; Kanso, Walaa; Karacson, Matthias; Karbach, Moritz; Karodia, Sarah; Kelsey, Matthew; Kenyon, Ian; Ketel, Tjeerd; Khanji, Basem; Khurewathanakul, Chitsanu; Klaver, Suzanne; Klimaszewski, Konrad; Kochebina, Olga; Kolpin, Michael; Komarov, Ilya; Koopman, Rose; Koppenburg, Patrick; Korolev, Mikhail; Kozlinskiy, Alexandr; Kravchuk, Leonid; Kreplin, Katharina; Kreps, Michal; Krocker, Georg; Krokovny, Pavel; Kruse, Florian; Kucewicz, Wojciech; Kucharczyk, Marcin; Kudryavtsev, Vasily; Kurek, Krzysztof; Kvaratskheliya, Tengiz; La Thi, Viet Nga; Lacarrere, Daniel; Lafferty, George; Lai, Adriano; Lambert, Dean; Lambert, Robert W; Lanfranchi, Gaia; Langenbruch, Christoph; Langhans, Benedikt; Latham, Thomas; Lazzeroni, Cristina; Le Gac, Renaud; van Leerdam, Jeroen; Lees, Jean-Pierre; Lefèvre, Regis; Leflat, Alexander; Lefrançois, Jacques; Leo, Sabato; Leroy, Olivier; Lesiak, Tadeusz; Leverington, Blake; Li, Yiming; Likhomanenko, Tatiana; Liles, Myfanwy; Lindner, Rolf; Linn, Christian; Lionetto, Federica; Liu, Bo; Lohn, Stefan; Longstaff, Iain; Lopes, Jose; Lopez-March, Neus; Lowdon, Peter; Lu, Haiting; Lucchesi, Donatella; Luo, Haofei; Lupato, Anna; Luppi, Eleonora; Lupton, Oliver; Machefert, Frederic; Machikhiliyan, Irina V; Maciuc, Florin; Maev, Oleg; Malde, Sneha; Manca, Giulia; Mancinelli, Giampiero; Maratas, Jan; Marchand, Jean François; Marconi, Umberto; Marin Benito, Carla; Marino, Pietro; Märki, Raphael; Marks, Jörg; Martellotti, Giuseppe; Martens, Aurelien; Martín Sánchez, Alexandra; Martinelli, Maurizio; Martinez Santos, Diego; Martinez Vidal, Fernando; Martins Tostes, Danielle; Massafferri, André; Matev, Rosen; Mathe, Zoltan; Matteuzzi, Clara; Mazurov, Alexander; McCann, Michael; McCarthy, James; McNab, Andrew; McNulty, Ronan; McSkelly, Ben; Meadows, Brian; Meier, Frank; Meissner, Marco; Merk, Marcel; Milanes, Diego Alejandro; Minard, Marie-Noelle; Moggi, Niccolò; Molina Rodriguez, Josue; Monteil, Stephane; Morandin, Mauro; Morawski, Piotr; Mordà, Alessandro; Morello, Michael Joseph; Moron, Jakub; Morris, Adam Benjamin; Mountain, Raymond; Muheim, Franz; Müller, Katharina; Mussini, Manuel; Muster, Bastien; Naik, Paras; Nakada, Tatsuya; Nandakumar, Raja; Nasteva, Irina; Needham, Matthew; Neri, Nicola; Neubert, Sebastian; Neufeld, Niko; Neuner, Max; Nguyen, Anh Duc; Nguyen, Thi-Dung; Nguyen-Mau, Chung; Nicol, Michelle; Niess, Valentin; Niet, Ramon; Nikitin, Nikolay; Nikodem, Thomas; Novoselov, Alexey; O'Hanlon, Daniel Patrick; Oblakowska-Mucha, Agnieszka; Obraztsov, Vladimir; Oggero, Serena; Ogilvy, Stephen; Okhrimenko, Oleksandr; Oldeman, Rudolf; Onderwater, Gerco; Orlandea, Marius; Otalora Goicochea, Juan Martin; Owen, Patrick; Oyanguren, Maria Arantza; Pal, Bilas Kanti; Palano, Antimo; Palombo, Fernando; Palutan, Matteo; Panman, Jacob; Papanestis, Antonios; Pappagallo, Marco; Pappalardo, Luciano; Parkes, Christopher; Parkinson, Christopher John; Passaleva, Giovanni; Patel, Girish; Patel, Mitesh; Patrignani, Claudia; Pazos Alvarez, Antonio; Pearce, Alex; Pellegrino, Antonio; Pepe Altarelli, Monica; Perazzini, Stefano; Perez Trigo, Eliseo; Perret, Pascal; Perrin-Terrin, Mathieu; Pescatore, Luca; Pesen, Erhan; Petridis, Konstantin; Petrolini, Alessandro; Picatoste Olloqui, Eduardo; Pietrzyk, Boleslaw; Pilař, Tomas; Pinci, Davide; Pistone, Alessandro; Playfer, Stephen; Plo Casasus, Maximo; Polci, Francesco; Poluektov, Anton; Polycarpo, Erica; Popov, Alexander; Popov, Dmitry; Popovici, Bogdan; Potterat, Cédric; Price, Eugenia; Prisciandaro, Jessica; Pritchard, Adrian; Prouve, Claire; Pugatch, Valery; Puig Navarro, Albert; Punzi, Giovanni; Qian, Wenbin; Rachwal, Bartolomiej; Rademacker, Jonas; Rakotomiaramanana, Barinjaka; Rama, Matteo; Rangel, Murilo; 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Seco, Marcos; Semennikov, Alexander; Sepp, Indrek; Serra, Nicola; Serrano, Justine; Sestini, Lorenzo; Seyfert, Paul; Shapkin, Mikhail; Shapoval, Illya; Shcheglov, Yury; Shears, Tara; Shekhtman, Lev; Shevchenko, Vladimir; Shires, Alexander; Silva Coutinho, Rafael; Simi, Gabriele; Sirendi, Marek; Skidmore, Nicola; Skwarnicki, Tomasz; Smith, Anthony; Smith, Edmund; Smith, Eluned; Smith, Jackson; Smith, Mark; Snoek, Hella; Sokoloff, Michael; Soler, Paul; Soomro, Fatima; Souza, Daniel; Souza De Paula, Bruno; Spaan, Bernhard; Sparkes, Ailsa; Spradlin, Patrick; Sridharan, Srikanth; Stagni, Federico; Stahl, Marian; Stahl, Sascha; Steinkamp, Olaf; Stenyakin, Oleg; Stevenson, Scott; Stoica, Sabin; Stone, Sheldon; Storaci, Barbara; Stracka, Simone; Straticiuc, Mihai; Straumann, Ulrich; Stroili, Roberto; Subbiah, Vijay Kartik; Sun, Liang; Sutcliffe, William; Swientek, Krzysztof; Swientek, Stefan; Syropoulos, Vasileios; Szczekowski, Marek; Szczypka, Paul; Szilard, Daniela; Szumlak, Tomasz; T'Jampens, Stephane; Teklishyn, Maksym; Tellarini, Giulia; Teubert, Frederic; Thomas, Christopher; Thomas, Eric; van Tilburg, Jeroen; Tisserand, Vincent; Tobin, Mark; Tolk, Siim; Tomassetti, Luca; Tonelli, Diego; Topp-Joergensen, Stig; Torr, Nicholas; Tournefier, Edwige; Tourneur, Stephane; Tran, Minh Tâm; Tresch, Marco; Tsaregorodtsev, Andrei; Tsopelas, Panagiotis; Tuning, Niels; Ubeda Garcia, Mario; Ukleja, Artur; Ustyuzhanin, Andrey; Uwer, Ulrich; Vagnoni, Vincenzo; Valenti, Giovanni; Vallier, Alexis; Vazquez Gomez, Ricardo; Vazquez Regueiro, Pablo; Vázquez Sierra, Carlos; Vecchi, Stefania; Velthuis, Jaap; Veltri, Michele; Veneziano, Giovanni; Vesterinen, Mika; Viaud, Benoit; Vieira, Daniel; Vieites Diaz, Maria; Vilasis-Cardona, Xavier; Vollhardt, Achim; Volyanskyy, Dmytro; Voong, David; Vorobyev, Alexey; Vorobyev, Vitaly; Voß, Christian; Voss, Helge; de Vries, Jacco; Waldi, Roland; Wallace, Charlotte; Wallace, Ronan; Walsh, John; Wandernoth, Sebastian; Wang, Jianchun; Ward, David; Watson, Nigel; Websdale, David; Whitehead, Mark; Wicht, Jean; Wiedner, Dirk; Wilkinson, Guy; Williams, Matthew; Williams, Mike; Wilson, Fergus; Wimberley, Jack; Wishahi, Julian; Wislicki, Wojciech; Witek, Mariusz; Wormser, Guy; Wotton, Stephen; Wright, Simon; Wu, Suzhi; Wyllie, Kenneth; Xie, Yuehong; Xing, Zhou; Xu, Zhirui; Yang, Zhenwei; Yuan, Xuhao; Yushchenko, Oleg; Zangoli, Maria; Zavertyaev, Mikhail; Zhang, Liming; Zhang, Wen Chao; Zhang, Yanxi; Zhelezov, Alexey; Zhokhov, Anatoly; Zhong, Liang; Zvyagin, Alexander

    2015-02-12

    The determination of track reconstruction efficiencies at LHCb using $J/\\psi\\rightarrow\\mu^{+}\\mu^{-}$ decays is presented. Efficiencies above $95\\%$ are found for the data taking periods in 2010, 2011, and 2012. The ratio of the track reconstruction efficiency of muons in data and simulation is compatible with unity and measured with an uncertainty of $0.8\\,\\%$ for data taking in 2010, and at a precision of $0.4\\,\\%$ for data taking in 2011 and 2012. For hadrons an additional $1.4\\,\\%$ uncertainty due to material interactions is assumed. This result is crucial for accurate cross section and branching fraction measurements in LHCb.

  1. Determination of the phase $\\phi_{s}$ at LHCb

    CERN Document Server

    Batozskaya, Varvara

    2018-01-01

    The determination of the mixing-induced $C\\!P$-violating phase $\\phi_{s}$ in the $B^{0}_{s}-\\bar{B}^{0}_{s}$ system is one of the key goals of the LHCb experiment. Using several $B^{0}_{s}$ decay modes it has been measured by the LHCb collaboration exploiting the Run~I data set. The first observation of the $B^{0}_{s}\\to\\eta_{c}\\phi$ and $B^{0}_{s}\\to\\eta_{c}\\pi^{+}\\pi^{-}$ decay modes which can be used to measure $\\phi_{s}$ with Run~II data is presented.

  2. Time-dependent asymmetries in Bs decays at LHCb

    CERN Document Server

    Blouw, Johan

    2007-01-01

    The LHCb experiment will search for New Physics in Bs mixing. The Bs mixing phase will be extracted from the measurement of the time-dependent CP asymmetry in exclusive Bs decays governed by the $b \\to c\\bar{c}s$ quark level transition. Large New Physics effects can be discovered or excluded with the data collected during the very first physics run of LHC. Based on Monte Carlo simulations of the LHCb detector, the expected sensitivity with 2 fb$^{-1}$ on the CP-violation parameter $\\phi_s$, is $\\sigma(\\phi_s)$ = 0.022.

  3. Hybrid Design, Procurement and Testing for the LHCb Silicon Tracker

    CERN Document Server

    Bay, A; Frei, R; Jiménez-Otero, S; Perrin, A; Tran, MT; Van Hunen, J J; Vervink, K; Vollhardt, A; Agari, M; Bauer, C; Blouw, J; Hofmann, W; Knöpfle, K T; Löchner, S; Schmelling, M; Schwingenheuer, B; Smale, N J; Adeva, B; Esperante-Pereira, D; Lois, C; Vázquez, P; Lehner, F; Bernhard, R P; Bernet, R; Gassner, J; Köstner, S; Needham, M; Steinkamp, O; Straumann, U; Volyanskyy, D; Voss, H; Wenger, A

    2005-01-01

    The Silicon Tracker of the LHCb experiment consists of four silicon detector stations positioned along the beam line of the experiment. The detector modules of each station are constructed from wide pitch silicon microstrip sensors. Located at the module's end, a polyimide hybrid is housing the front-end electronics. The assembly of the more than 600 hybrids has been outsourced to industry. We will report on the design and production status of the hybrids for the LHCb Silicon Tracker and describe the quality assurance tests. Particular emphasis is laid on the vendor qualifying and its impact on our hybrid design that we experienced during the prototyping phase.

  4. A computer-generated image of the LHCb detector

    CERN Multimedia

    Richard Jacobsson

    2004-01-01

    Unlike most of the detectors on the LHC, which use barrel detectors, the LHCb detector will use walls of sub-detectors to study the particles produced in the 14 TeV proton-proton collisions. This arrangement is used as the bottom and anti-bottom quark pairs produced in the collision, whose decays will be studied, travel close to the path of the colliding beams. LHCb will investigate Naure's preference for matter over antimatter through a process known as CP violation.

  5. Measurement of the track reconstruction efficiency at LHCb

    International Nuclear Information System (INIS)

    Collaboration, The LHCb

    2015-01-01

    The determination of track reconstruction efficiencies at LHCb using J/ψ→μ + μ - decays is presented. Efficiencies above 95% are found for the data taking periods in 2010, 2011, and 2012. The ratio of the track reconstruction efficiency of muons in data and simulation is compatible with unity and measured with an uncertainty of 0.8 % for data taking in 2010, and at a precision of 0.4 % for data taking in 2011 and 2012. For hadrons an additional 1.4 % uncertainty due to material interactions is assumed. This result is crucial for accurate cross section and branching fraction measurements in LHCb

  6. Proposal for a level 0 calorimeter trigger system for LHCb

    CERN Document Server

    Bertin, A; Capponi, M; D'Antone, I; De Castro, S; Donà, R; Galli, D; Giacobbe, B; Marconi, U; Massa, I; Piccinini, M; Poli, M; Semprini-Cesari, N; Spighi, R; Vecchi, S; Villa, M; Vitale, A; Zoccoli, A; Zoccoli, Antonio

    1999-01-01

    In this note we present a complete system for the Level-0 LHCb calorimeter triggers. The system is derived from the electromagnetic calorimeter pre-trigger developed for the HERA-B experiment. The proposed system follows closely the Level-0 trigger algorithms presented in the LHCb Technical Proposal based on an electromagnetic and hadronic showers analysis performed on 3x3 calorimeter matrix. The general architecture presented is completely synchronous and quite flexible to allow adaptation to further improvements on the Level-0 trigger algorithms.

  7. New results in LU/LFV tests with LHCb

    CERN Document Server

    Prisciandaro, Jessica

    2017-01-01

    During the Run 1 of the LHC, the LHCb experiment has collected a large sample of beauty-hadrons that corresponds to an integrated luminosity of 3.0 fb$^{−1}$ at $pp$ centre-of-mass energy of 7 and 8 TeV. In the following, an overview of the rare decay measurements the LHCb collaboration performed during Run 1 is presented. In particular, recent tests of lepton flavour universality, with deviations also observed in semileptonic decays, and searches for lepton flavour violation decays will be presented.

  8. Jagiellonian University Heavy flavour highlights from the LHCb

    CERN Document Server

    INSPIRE-00640989

    2017-01-01

    This document presents an overview of the flavour anomalies observed by the LHCb experiment. All results are based on the dataset collected during the full LHC Run 1 by the LHCb Collaboration. Measurements of branching fractions of several $b \\rightarrow sll$ decays are presented together with the angular analysis of $B^{0} \\rightarrow K∗ \\mu^{+}\\mu^{−}$ decays and the lepton flavour universality tests R(K) and R(D∗). In addition, a direct search for a new light scalar particle in the $B^{+} \\rightarrow K^{+}\\chi$ decay, with $\\chi \\rightarrow \\mu^{+} \\mu^{-}$, is presented.

  9. LHC-B: a dedicated LHC collider beauty experiment

    International Nuclear Information System (INIS)

    Erhan, S.

    1995-01-01

    LHC-B is a forward detector optimized for the study of CP-violation and other rare phenomena in the decays of beauty particles at the LHC. An open geometry forward detector design, with good mass, vertex resolution and particle identification, will facilitate the collection of a large numbers of event samples in diverse B decay channels and allow for a thorough understanding of the systematic uncertainties. With the expected large event statistics, LHC-B will be able to test the closure of the unitarity triangle and make sensitive tests of the Standard Model description of CP-violation. Here we describe the experiment and summarize its anticipated performance. (orig.)

  10. Virtualization for the LHCb Online system

    International Nuclear Information System (INIS)

    Bonaccorsi, Enrico; Brarda, Loic; Moine, Gary; Neufeld, Niko

    2011-01-01

    Virtualization has long been advertised by the IT-industry as a way to cut down cost, optimise resource usage and manage the complexity in large data-centers. The great number and the huge heterogeneity of hardware, both industrial and custom-made, has up to now led to reluctance in the adoption of virtualization in the IT infrastructure of large experiment installations. Our experience in the LHCb experiment has shown that virtualization improves the availability and the manageability of the whole system. We have done an evaluation of available hypervisors / virtualization solutions and find that the Microsoft HV technology provides a high level of maturity and flexibility for our purpose. We present the results of these comparison tests, describing in detail, the architecture of our virtualization infrastructure with a special emphasis on the security for services visible to the outside world. Security is achieved by a sophisticated combination of VLANs, firewalls and virtual routing - the cost and benefits of this solution are analysed. We have adapted our cluster management tools, notably Quattor, for the needs of virtual machines and this allows us to migrate smoothly services on physical machines to the virtualized infrastructure. The procedures for migration will also be described. In the final part of the document we describe our recent R and D activities aiming to replacing the SAN-backend for the virtualization by a cheaper iSCSI solution - this will allow to move all servers and related services to the virtualized infrastructure, excepting the ones doing hardware control via non-commodity PCI plugin cards.

  11. LHCb: Tagged time-dependent angular analysis of $B^0_s \\to J/\\psi\\phi$ decays at LHCb

    CERN Multimedia

    Dupertuis, Frédéric

    2012-01-01

    The determination of the CP-violating phase $\\phi_s$ in $B^0_s \\to J/\\psi\\phi$ decays is one of the key goals of the LHCb experiment. Its value is predicted to be very small in the Standard Model but can be significantly enhanced in many models of new physics. We present the world’s best measurement of $\\phi_s$ and the first observation of a non-zero $\\Delta\\Gamma_s$ based upon 1 fb$^{−1}$ of data collected at LHCb during 2011.

  12. LHCb: FPGA-based, radiation-tolerant on-detector electronics for the upgrade of the LHCb Outer Tracker Detector

    CERN Multimedia

    Vink, W

    2013-01-01

    The LHCb experiment studies B-decays at the LHC. The Outer Tracker straw tubes detects charged decay particles. The on-detector electronics will be upgraded to be able to digitize and transmit drift-times at every LHC crossing without the need for a hardware trigger. FPGAs have been preferred to application-specific integrated circuits to implement dead-time free TDCs, able to transmit data volumes of up to 36 Gbits/s per readout unit, including the possibility of performing zero suppression. Extensive irradiation tests have been carried out to validate the usage of field-programmable devices in the hostile environment of the LHCb tracking system.

  13. LHCb: Study of the Performance of the LHCb Muon System with First LHC Data

    CERN Multimedia

    Cardini, A

    2010-01-01

    The LHCb Muon System is composed by five detection stations (M1-M5), one upstream and four downstream of the calorimeter system, equipped on the 99% of the surface with a total of 1368 Multi-Wire Proportional Chambers (MWPC). Triple-GEM detectors with digital pad readout were chosen for the innermost region of the first station thanks to their excellent performances, in particular for what concerns rate capability and radiation hardness. In order to allow a fast evaluation of the transverse momentum of muons, all detectors are required to have a high efficiency, a fast response and a good space resolution with a readout granularity that decreases with the distance from the beam axis. The detector installation phase (2006-2009) was followed by an extensive commissioning and events were acquired with pulse trigger to several millions of cosmic tracks already in the commissioning phase and are being used for the first LHC collisions.

  14. LHCb: Beam-gas background for LHCb at 3.5 TeV

    CERN Multimedia

    Brett, D R; Corti, G; Alessio, F; Jacobsson, R; Talanov, V; Lieng, M H

    2011-01-01

    We consider the machine induced backgrounds for LHCb arising from collisions of the beam with residual gas in the long straight sections of the LHC close to the experiment. We concentrate on the background particle fluxes initiated by inelastic beam-gas interactions with a direct line of sight to the experiment, with the potential impact on the experiment increasing for larger beam currents and changing gas pressures. In this paper we calculate the background rates for parameters foreseen with LHC running in 2011, using realistic residual pressure profiles. We also discuss the effect of using a pressure profile formulated in terms of equivalent hydrogen, through weighting of other residual gases by their cross section, upon the radial fluxes from the machine and the detector response. We present the expected rates and the error introduced through this approximation.

  15. LHCb: Quarkonia production in $p$-­Pb collision at LHCb

    CERN Multimedia

    Li, Y

    2014-01-01

    The production of $J/\\psi$ and $\\Upsilon$ mesons decaying into dimuon final state is studied at the LHCb experiment, with rapidity 1.5 < y < 4.0 or −5.0 < y < −2.5 and transverse momentum pT < 15 GeV/c, in proton-lead collisions at a proton-nucleon centre-of-mass energy$\\sqrt{s}$ NN = 5 TeV. The analysis is based on a data sample corresponding to an integrated luminosity of 1.6 nb$^{−1}$. The forward-backward production ratio and the nuclear modification factor are determined for $J/\\psi$ and Y(1S). Indication of forward backward production asymmetry is observed. There is also an indication of $J/\\psi$ and Y(1S)production suppression with respect to proton-proton collisions in forward region and anti-shadowing effect in backward region.

  16. LHCb : Novel real-time alignment and calibration of the LHCb Detector in Run2

    CERN Multimedia

    Tobin, Mark

    2015-01-01

    LHCb has introduced a novel real-time detector alignment and calibration strategy for LHC Run 2. Data collected at the start of the fill will be processed in a few minutes and used to update the alignment, while the calibration constants will be evaluated for each run. This procedure will improve the quality of the online alignment. For example, the vertex locator is retracted and reinserted for stable beam collisions in each fill to be centred on the primary vertex position in the transverse plane. Consequently its position changes on a fill-by-fill basis. Critically, this new realtime alignment and calibration procedure allows identical constants to be used in the online and offline reconstruction, thus improving the correlation between triggered and offline selected events. This offers the opportunity to optimise the event selection in the trigger by applying stronger constraints. The online calibration facilitates the use of hadronic particle identification using the RICH detectors at the trigger level. T...

  17. Measurement of b-flavoured hadron lifetimes at LHCb

    CERN Document Server

    Ilieva, Simona Ilieva

    2016-01-01

    The aim of this Student Project Note is to describe precise lifetime measurements of b-flavored hadrons at LHCb. The analysis is based on Monte Carlo data simulating Run2 2015 conditions. Decay-time biases introduced at every step of the reconstruction, trigger and selection of candidates are studied. Several methods to correct for Lower acceptance are presented.

  18. The LHCb Inner Tracker Module Production Steps and Quality Assurance

    CERN Document Server

    Bettler, M O; Esperante, D; Fauland, P; van Hunen, J; Knecht, M; Koestner, S; Tran, M T; Perez Trigo, E; Vazquez, P; Voss, H

    2010-01-01

    This note describes the various production step for the LHCb Inner Tracker silicon modules. We quickly sketch where the various items are produced and mention their acceptance criteria where applicable. A detail description is given of the various production and testing steps of the silicon detector modules in Lausanne and at CERN.

  19. Characterisation and commissioning of the LHCb VELO detector

    CERN Document Server

    AUTHOR|(CDS)2069345; Jans, E

    2009-01-01

    The LHCb detector is a one-armed spectrometer at the Large Hadron Collider. It has been designed to look for physics beyond the Standard Model through high precision measurements of CP-violation in the B-system and through the detection of rare B-decays. The success of LHCb relies heavily on its vertex detector, the VELO (VErtex LOcator), which will be used to trigger on B decay vertices and reconstruct them with micrometre accuracy. While small in size, comprising just 84 sensors, the VELO construction poses special challenges due to the high accuracy required and the proximity to the LHC beams. The detector will be required to operate under vacuum and will be exposed to high radiation levels. The first section of the thesis gives a brief introduction to the LHCb detector and the physics programme of the LHCb collaboration. The following sections review the VELO design and give and in-depth report on measurements of the detector performance based on data collected in beam tests. Topics covered are hit resolu...

  20. Grounding, Shielding and Power Distribution for the LHCb Silicon Tracking

    CERN Document Server

    Bauer, C; Frei, R; Straumann, U; Vázquez, P; Vollhardt, A

    2005-01-01

    This note lists the relevant items for power and grounding, it explains the sensitive detector input signal circuits and describes the grounding, power distribution and line filtering measures applied to each of the electrical units of the LHCb silicon tracking system. This note deals with both silicon sub-projects, the Inner Tracker (IT) and the Trigger Tracker (TT).

  1. LHCb experiment reports observation of exotic pentaquark particles

    CERN Multimedia

    Dominguez, Daniel

    2015-01-01

    Illustration of the possible layout of the quarks in a pentaquark particle such as those discovered at LHCb. The five quarks might be tightly bonded. They might also be assembled into a meson (one quark and one antiquark) and a baryon (three quarks), weakly bonded together.

  2. The RICH with Aerogel for the LHCb Experiment

    CERN Document Server

    Bellunato, T; Matteuzzi, C; Musy, M; Negri, P; Perego, D L

    2006-01-01

    We report on the status of the art of the aerogel project for LHCb, from the production, in terms of specifications and achieved quality, to the optical and beam tests performed to qualify the material as a Cherenkov radiator. A brief summary of the ageing and radiation tolerance tests performed on some aerogel tiles is also given.

  3. The RICH with Aerogel for the LHCb Experiment

    International Nuclear Information System (INIS)

    Bellunato, T.; Calvi, M.; Matteuzzi, C.; Musy, M.; Negri, P.; Perego, D.L.

    2006-01-01

    We report on the status of the art of the aerogel project for LHCb, from the production, in terms of specifications and achieved quality, to the optical and beam tests performed to qualify the material as a Cherenkov radiator. A brief summary of the ageing and radiation tolerance tests performed on some aerogel tiles is also given

  4. Road map for selected key measurements from LHCb

    CERN Document Server

    Adeva, B.; Affolder, A.; Ajaltouni, Z.; Albrecht, J.; Alessio, F.; Alexander, M.; Alvarez Cartelle, P.; Alves, A.A., Jr; Amato, S.; Amhis, Y.; Amoraal, J.; Anderson, J.; Aquines Gutierrez, O.; Arrabito, L.; Artuso, M.; Aslanides, E.; Auriemma, G.; Bachmann, S.; Bagaturia, Y.; Bailey, D.S.; Balagura, V.; Baldini, W.; Pazos, MdC.Barandela; Barlow, R.J.; Barsuk, S.; Bates, A.; Bauer, C.; Bauer, Th.; Bay, A.; Bediaga, I.; Belous, K.; Belyaev, I.; Benayoun, M.; Bencivenni, G.; Bernet, R.; Bettler, M.O.; Bizzeti, A.; Blake, T.; Blanc, F.; Blanks, C.; Blouw, J.; Blusk, S.; Bobrov, A.; Bocci, V.; Bondar, A.; Bondar, N.; Bonivento, W.; Borghi, S.; Borgia, A.; Bos, E.; Bowcock, T.J.V.; Bozzi, C.; Bressieux, J.; Brisbane, S.; Britsch, M.; Brook, N.H.; Brown, H.; Buchler-Germann, A.; Buytaert, J.; Cachemiche, J.P.; Cadeddu, S.; Caicedo Carvajal, J.M.; Callot, O.; Calvi, M.; Calvo Gomez, M.; Camboni, A.; Cameron, W.; Campana, P.; Carbone, A.; Carboni, G.; Cardini, A.; Carson, L.; Carvalho Akiba, K.; Casse, G.; Cattaneo, M.; Charles, M.; Charpentier, Ph.; Chlopik, A.; Ciambrone, P.; Cid Vidal, X.; Clark, P.J.; Clarke, P.E.L.; Clemencic, M.; Cliff, H.V.; Closier, J.; Coca, C.; Coco, V.; Cogan, J.; Collins, P.; Constantin, F.; Conti, G.; Contu, A.; Corti, G.; Cowan, G.A.; D'Almagne, B.; D'Ambrosio, C.; d'Enterria, D.G.; Da Silva, W.; David, P.; De Bonis, I.; De Capua, S.; De Cian, M.; De Lorenzi, F.; De Miranda, J.M.; De Paula, L.; De Simone, P.; De Vries, H.; Decamp, D.; Degaudenzi, H.; Deissenroth, M.; Del Buono, L.; Deplano, C.; Deschamps, O.; Dettori, F.; Dickens, J.; Dijkstra, H.; Dima, M.; Donleavy, S.; Reis, A.C.dos; Dovbnya, A.; Pree, T.Du; Duval, P.Y.; Dwyer, L.; Dzhelyadin, R.; Eames, C.; Easo, S.; Egede, U.; Egorychev, V.; Eisele, F.; Eisenhardt, S.; Eklund, L.; Esperante Pereira, D.; Esteve, L.; Eydelman, S.; Fanchini, E.; Farber, C.; Fardell, G.; Farinelli, C.; Farry, S.; Fave, V.; Fernandez Albor, V.; Ferro-Luzzi, M.; Filippov, S.; Fitzpatrick, C.; Fontanelli, F.; Forty, R.; Frank, M.; Frei, C.; Frosini, M.; Fungueirino Pazos, J.L.; Furcas, S.; Gallas Torreira, A.; Galli, D.; Gandelman, M.; Gao, Y.; Garnier, J-C.; Garrido, L.; Gaspar, C.; Gauvin, N.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Gibson, V.; Gilitsky, Yu.; Gligorov, V.V.; Gobel, C.; Golubkov, D.; Golutvin, A.; Gomes, A.; Grabalosa Gandara, M.; Graciani Diaz, R.; Granado Cardoso, L.A.; Grauges, E.; Graziani, G.; Grecu, A.; Guerrer, G.; Gushchin, E.; Guz, Yu.; Guzik, Z.; Gys, T.; Hachon, F.; Haefeli, G.; Haines, S.C.; Hampson, T.; Hansmann-Menzemer, S.; Harji, R.; Harnew, N.; Harrison, P.F.; He, J.; Hennessy, K.; Henrard, P.; Hernando Morata, J.A.; Hicheur, A.; Hicks, E.; Hofmann, W.; Holubyev, K.; Hopchev, P.; Hulsbergen, W.; Hunt, P.; Huse, T.; Huston, R.S.; Hutchcroft, D.; Iakovenko, V.; Escudero, C.Iglesias; Imong, J.; Jacobsson, R.; Jahjah Hussein, M.; Jans, E.; Jansen, F.; Jaton, P.; Jean-Marie, B.; John, M.; Jones, C.R.; Jost, B.; Kapusta, F.; Karbach, T.M.; Keaveney, J.; Kerzel, U.; Ketel, T.; Keune, A.; Khalil, S.; Khanji, B.; Kim, Y.M.; Knecht, M.; Knopf, J.; Koblitz, S.; Konoplyannikov, A.; Koppenburg, P.; Korolko, I.; Kozlinskiy, A.; Krasowski, M.; Kravchuk, L.; Krokovny, P.; Kruzelecki, K.; Kucharczyk, M.; Kudryashov, I.; Kvaratskheliya, T.; Lacarrere, D.; Lai, A.; Lambert, R.W.; Lanfranchi, G.; Langenbruch, C.; Latham, T.; Le Gac, R.; Lefevre, R.; Leflat, A.; Lefrancois, J.; Leroy, O.; Lessnoff, K.; Li, L.; Li, Y.Y.; Libby, J.; Lieng, M.; Lindner, R.; Lindsey, S.; Linn, C.; Liu, B.; Liu, G.; Lopes, J.H.; Lopez Asamar, E.; Luisier, J.; Machefert, F.; Machikhiliyan, I.; Maciuc, F.; Maev, O.; Magnin, J.; Maier, A.; Mamunur, R.M.D.; Manca, G.; Mancinelli, G.; Mangiafave, N.; Marconi, U.; Marin, F.; Marks, J.; Martellotti, G.; Martens, A.; Martin, L.; Martinez Santos, D.; Mathe, Z.; Matteuzzi, C.; Matveev, V.; Mazurov, A.; McGregor, G.; Mcharek, B.; Mclean, C.; McNulty, R.; Merk, M.; Merkel, J.; Merkin, M.; Messi, R.; Metlica, F.C.D.; Michalowski, J.; Miglioranzi, S.; Minard, M.N.; Monteil, S.; Moran, D.; Morris, J.V.; Mountain, R.; Mous, I.; Muheim, F.; Muresan, R.; Murtas, F.; Muryn, B.; Musy, M.; Mylroie-Smith, J.; Naik, P.; Nakada, T.; Nandakumar, R.; Nardulli, J.; Natkaniec, Z.; Nedos, M.; Needham, M.; Neufeld, N.; Nicolas, L.; Nies, S.; Niess, V.; Nikitin, N.; Noor, A.; Oblakowska-Mucha, A.; Obraztsov, V.; Oggero, S.; Okhrimenko, O.; Oldeman, R.; Orlandea, M.; Ostankov, A.; Palacios, J.; Palutan, M.; Panman, J.; Papadelis, A.; Papanestis, A.; Pappagallo, M.; Parkes, C.; Passaleva, G.; Patel, G.D.; Patel, M.; Paterson, S.K.; Patrick, G.N.; Pauna, E.; Pauna, C.; Pavel, C.; Pazos Alvarez, A.; Pellegrino, A.; Penso, G.; Pepe Altarelli, M.; Perazzini, S.; Perego, D.L.; Perez-Calero Yzquierdo, A.; Perez Trigo, E.; Perret, P.; Pessina, G.; Petrella, A.; Petrolini, A.; Pietrzyk, B.; Pinci, D.; Playfer, S.; Plo Casasus, M.; Polok, G.; Poluektov, A.; Polycarpo, E.; Popov, D.; Popovici, B.; Poss, S.; Potterat, C.; Powell, A.; Pozzi, S.; Pugatch, V.; Puig Navarro, A.; Qian, W.; Rademacker, J.H.; Rakotomiaramanana, B.; Raniuk, I.; Raven, G.; Redford, S.; Reece, W.; Ricciardi, S.; Rinnert, K.; Robbe, P.; Rodrigues, E.; Rodrigues, F.; Rodriguez Cobo, C.; Rodriguez Perez, P.; Rogers, G.J.; Romanovsky, V.; Rospabe, G.; Ruf, T.; Ruiz, H.; Sabatino, G.; Saborido Silva, J.J.; Sagidova, N.; Saitta, B.; Salzmann, C.; Sambade Varela, A.; Sannino, M.; Santacesaria, R.; Santinelli, R.; Santovetti, E.; Sapunov, M.; Sarti, A.; Satriano, C.; Satta, A.; Savrie, M.; Savrina, D.; Schaack, P.; Schiller, M.; Schleich, S.; Schmelling, M.; Schmidt, B.; Schneider, O.; Schopper, A.; Schune, M.H.; Schwemmer, R.; Sciubba, A.; Seco, M.; Semennikov, A.; Senderowska, K.; Serra, N.; Serrano, J.; Shao, B.; Shapkin, M.; Shapoval, I.; Shatalov, P.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, V.; Simioni, E.; Skottowe, H.P.; Skwarnicki, T.; Smith, A.C.; Sobczak, K.; Soler, F.J.P.; Solomin, A.; Somogy, P.; Soomro, F.; De Paula, B.Souza; Spaan, B.; Sparkes, A.; Spiridenkov, E.; Spradlin, P.; Stagni, F.; Steinkamp, O.; Stoica, S.; Stone, S.; Straumann, U.; Styles, N.; Syryczynski, K.; Szczekowski, M.; Szczypka, P.; Szumlak, T.; T'Jampens, S.; Terrier, H.; Teubert, F.; Thomas, C.; Thomas, E.; Tobin, M.; Topp-Joergensen, S.; Tran, M.T.; Traynor, S.; Tsaregorodtsev, A.; Tuning, N.; Ukleja, A.; Ullaland, O.; Uwer, U.; Vagnoni, V.; Valenti, G.; van Beuzekom, M.; van den Brand, J.; van Eijk, D.; van Herwijnen, E.; van Lysebetten, A.; van Tilburg, J.; Vazquez Gomez, R.; Vazquez Regueiro, P.; Vecchi, S.; Velthuis, J.J.; Veltri, M.; Vervink, K.; Viaud, B.; Videau, I.; Vilasis-Cardona, X.; Vollhardt, A.; Vorobyev, A.; Vorobyev, An.; Voss, H.; Wacker, K.; Wandernoth, S.; Wang, J.; Ward, D.R.; Websdale, D.; Whitehead, M.; Wiedner, D.; Wiggers, L.; Wilkinson, G.; Williams, M.; Wilson, F.F.; Witek, M.; Witzeling, W.; Wotton, S.A.; Wyllie, K.; Xie, Y.; Xing, F.; Yang, Z.; Ybeles Smit, G.; Young, R.; Yushchenko, O.; Zhang, L.; Zhang, Y.; Zhelezov, A.; Zwahlen, N.

    2010-01-01

    Six of the key physics measurements that will be made by the LHCb experiment, concerning CP asymmetries and rare B decays, are discussed in detail. The "road map" towards the precision measurements is presented, including the use of control channels and other techniques to understand the performance of the detector with the first data from the LHC.

  5. The signal shape from the LHCb vertex locator prototype detectors

    International Nuclear Information System (INIS)

    Charles, M.

    2003-01-01

    Measurements of the SCT128A ASIC pulse shape, when reading out non-irradiated and irradiated prototype detectors for the LHCb VELO, are presented. The detectors studied were two n-on-n prototype detectors fabricated by Hamamatsu, and a p-on-n prototype detector fabricated by MICRON

  6. VeloPix ASIC for the LHCb VELO Upgrade

    CERN Multimedia

    Cid Vidal, Xabier

    2015-01-01

    The LHCb Vertex Detector (VELO) will be upgraded in 2018 along with the other subsystems of LHCb in order to enable full detector readout at 40 MHz. LHCb will run without a hardware trigger and all data will be fed directly to the software triggering algorithms in the CPU farm. The upgraded VELO is a lightweight silicon hybrid pixel detector with 55 um square pixels, operating in vacuum in close proximity to the LHC beams. The readout will be provided by a dedicated front end ASIC, dubbed VeloPix, matched to the LHCb luminosity requirements. VeloPix is a binary pixel chip with a matrix of 256 x 256 pixels, covering an area of 2 cm^2. It is designed in a 130 nm CMOS technology, and is closely related to the Timepix3, from the Medipix family of ASICs. The principal challenge that the chip has to meet is a hit rate of up to 900 Mhits/s/ASIC, resulting in a data rate of more than 16 Gbit/s. Combining pixels into groups of 2x4 super-pixels enables the use of shared logic and a reduction of bandwidth due to combine...

  7. LHCb RICH Online-Monitor and Data-Quality

    CERN Multimedia

    Kerzel, U

    2009-01-01

    The LHCb experiment at the LHC (CERN) has been optimised for high precision measurements of the beauty quark sector. Its main objective is to precisely determine and over-constrain the parameters of the CKM mixing matrix, and to search for further sources of CP violation and new physics beyond the Standard Model in rare B-decays. Efficient particle identification at high purities over a wide momentum range from around 1 to ~100GeV/c is vital to many LHCb analyses. Central to the LHCb particle identification strategy are two Ring Imaging CHerenkov (RICH) detectors which use Silica Aerogel and C4F10 and CF4 gas radiators. A rigorous quality control scheme is being developed to insure that the data recorded by the RICH detector meets the stringent requirements of the physics analyses. The talk summarises the LHCb RICH online monitoring and data-quality strategy. Multiple dedicated algorithms are deployed to detect any potential issue already during data-taking ranging from integrity checks, mis-alignments to cha...

  8. Searching for confining hidden valleys at LHCb, ATLAS, and CMS

    Science.gov (United States)

    Pierce, Aaron; Shakya, Bibhushan; Tsai, Yuhsin; Zhao, Yue

    2018-05-01

    We explore strategies for probing hidden valley scenarios exhibiting confinement. Such scenarios lead to a moderate multiplicity of light hidden hadrons for generic showering and hadronization similar to QCD. Their decays are typically soft and displaced, making them challenging to probe with traditional LHC searches. We show that the low trigger requirements and excellent track and vertex reconstruction at LHCb provide a favorable environment to search for such signals. We propose novel search strategies in both muonic and hadronic channels. We also study existing ATLAS and CMS searches and compare them with our proposals at LHCb. We find that the reach at LHCb is generically better in the parameter space we consider here, even with optimistic background estimations for ATLAS and CMS searches. We discuss potential modifications at ATLAS and CMS that might make these experiments competitive with the LHCb reach. Our proposed searches can be applied to general hidden valley models as well as exotic Higgs boson decays, such as in twin Higgs models.

  9. The certification process of the LHCb distributed computing software

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    DIRAC contains around 200 thousand lines of python code, and LHCbDIRAC around 120 thousand. The testing process for each release consists of a number of steps, that includes static code analysis, unit tests, integration tests, regression tests, system tests. We dubbed the full p...

  10. Gas system proposal for the LHCb muon system

    CERN Document Server

    Hahn, F; Lindner, R

    2001-01-01

    This document describes the gas system proposed for the LHCb Muon system, following the Gas Working Group mandate to ensure the uniform approach to gas technology and controls across the LHC detectors. Standard technical design modules are employed as fas as possible, in order to minimise design overheads and long term support costs.

  11. Monitoring radiation damage in the LHCb Silicon Tracker

    CERN Multimedia

    Graverini, Elena

    2018-01-01

    The purpose of LHCb is to search for indirect evidence of new physics in decays of heavy hadrons. The LHCb detector is a single-arm forward spectrometer with precise silicon-strip detectors in the regions with highest particle occupancies. The non-uniform exposure of the LHCb sensors makes it an ideal laboratory to study radiation damage effects in silicon detectors. The LHCb Silicon Tracker is composed of an upstream tracker, the TT, and of the inner part of the downstream tracker (IT). Dedicated scans are regularly taken, which allow a precise measurement of the charge collection efficiency (CCE) and the calibration of the operational voltages. The measured evolution of the effective depletion voltage $V_{depl}$ is shown, and compared with the Hamburg model prediction. The magnitudes of the sensor leakage current are also analysed and compared to their expected evolution according to phenomenological models. Our results prove that both the TT and the IT will withstand normal operation until the end of the L...

  12. Search for strange baryon electric dipole moment at LHCb

    CERN Document Server

    Lewis, Daniel James

    2017-01-01

    A search for the EDM of $\\Lambda$ baryons using the LHCb detector is proposed. In order to perform this search, the reconstruction of $\\Lambda$ baryons using T tracks must be possible. This note presents the reconstruction techniques and resolution studies that demonstrate that this is indeed feasible.

  13. arXiv CP violation in $b$ hadrons at LHCb

    CERN Document Server

    INSPIRE-00028041

    The most recent results on CP violation in $b$ hadrons obtained by the LHCb Collaboration with Run I and years 2015-2016 of Run II are reviewed. The different types of violation are covered by the studies presented in this paper.

  14. Integration of cloud resources in the LHCb distributed computing

    International Nuclear Information System (INIS)

    García, Mario Úbeda; Stagni, Federico; Cabarrou, Baptiste; Rauschmayr, Nathalie; Charpentier, Philippe; Closier, Joel; Muñoz, Víctor Méndez

    2014-01-01

    This contribution describes how Cloud resources have been integrated in the LHCb Distributed Computing. LHCb is using its specific Dirac extension (LHCbDirac) as an interware for its Distributed Computing. So far, it was seamlessly integrating Grid resources and Computer clusters. The cloud extension of DIRAC (VMDIRAC) allows the integration of Cloud computing infrastructures. It is able to interact with multiple types of infrastructures in commercial and institutional clouds, supported by multiple interfaces (Amazon EC2, OpenNebula, OpenStack and CloudStack) – instantiates, monitors and manages Virtual Machines running on this aggregation of Cloud resources. Moreover, specifications for institutional Cloud resources proposed by Worldwide LHC Computing Grid (WLCG), mainly by the High Energy Physics Unix Information Exchange (HEPiX) group, have been taken into account. Several initiatives and computing resource providers in the eScience environment have already deployed IaaS in production during 2013. Keeping this on mind, pros and cons of a cloud based infrasctructure have been studied in contrast with the current setup. As a result, this work addresses four different use cases which represent a major improvement on several levels of our infrastructure. We describe the solution implemented by LHCb for the contextualisation of the VMs based on the idea of Cloud Site. We report on operational experience of using in production several institutional Cloud resources that are thus becoming integral part of the LHCb Distributed Computing resources. Furthermore, we describe as well the gradual migration of our Service Infrastructure towards a fully distributed architecture following the Service as a Service (SaaS) model.

  15. Integration of Cloud resources in the LHCb Distributed Computing

    Science.gov (United States)

    Úbeda García, Mario; Méndez Muñoz, Víctor; Stagni, Federico; Cabarrou, Baptiste; Rauschmayr, Nathalie; Charpentier, Philippe; Closier, Joel

    2014-06-01

    This contribution describes how Cloud resources have been integrated in the LHCb Distributed Computing. LHCb is using its specific Dirac extension (LHCbDirac) as an interware for its Distributed Computing. So far, it was seamlessly integrating Grid resources and Computer clusters. The cloud extension of DIRAC (VMDIRAC) allows the integration of Cloud computing infrastructures. It is able to interact with multiple types of infrastructures in commercial and institutional clouds, supported by multiple interfaces (Amazon EC2, OpenNebula, OpenStack and CloudStack) - instantiates, monitors and manages Virtual Machines running on this aggregation of Cloud resources. Moreover, specifications for institutional Cloud resources proposed by Worldwide LHC Computing Grid (WLCG), mainly by the High Energy Physics Unix Information Exchange (HEPiX) group, have been taken into account. Several initiatives and computing resource providers in the eScience environment have already deployed IaaS in production during 2013. Keeping this on mind, pros and cons of a cloud based infrasctructure have been studied in contrast with the current setup. As a result, this work addresses four different use cases which represent a major improvement on several levels of our infrastructure. We describe the solution implemented by LHCb for the contextualisation of the VMs based on the idea of Cloud Site. We report on operational experience of using in production several institutional Cloud resources that are thus becoming integral part of the LHCb Distributed Computing resources. Furthermore, we describe as well the gradual migration of our Service Infrastructure towards a fully distributed architecture following the Service as a Service (SaaS) model.

  16. Central Au on Au collisions

    Energy Technology Data Exchange (ETDEWEB)

    Alard, J.P.; Amouroux, V. [Labo de Phys. Corp., IN2P3-CRNS, Univ. Blaise Pascal, Clermont-Fd. (France); Basrak, Z. [Rudjer Boskovic Institute, Zagreb (Croatia)] [and others; FOPI-Collaboration

    1995-02-06

    In nucleus-nucleus collisions the initial relative kinetic energy of target and projectile is available for internal excitation of the interacting system; it is however still not well established to what extent local equilibrium and thermalisation occur. Local equilibrium is of interest to derive, within the formalism of transport equations and of the equation of state, (EOS), general properties of compressed and excited nuclear matter. Such approach describes in relatively simple terms the complex many body interactions occuring within extended baryonic and hadronic (or quark) matter. For a basic microscopic understanding it is highly desirable to investigate the elementary in-medium interactions in relation to the free elementary processes. Excitation function measurements of central collisions between the heaviest available nuclei (like Au on Au), supply the best ground for such studies: the highest degree of thermalisation and compression is expected for such reactions. The consideration presented here of energy thermalisation and of an expanding system clusterizing at freeze-out in a situation close to the liquid gas phase transition can be of interest to astrophysics as well as to the quark gluon plasma deconfinement studied in nucleus-nucleus collisions at the higher energy regime of CERN and Brookhaven. (orig.).

  17. Particle identification at LHCb: new calibration techniques and machine learning classification algorithms

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    Particle identification (PID) plays a crucial role in LHCb analyses. Combining information from LHCb subdetectors allows one to distinguish between various species of long-lived charged and neutral particles. PID performance directly affects the sensitivity of most LHCb measurements. Advanced multivariate approaches are used at LHCb to obtain the best PID performance and control systematic uncertainties. This talk highlights recent developments in PID that use innovative machine learning techniques, as well as novel data-driven approaches which ensure that PID performance is well reproduced in simulation.

  18. LHCB: Non-POSIX File System for the LHCB Online Event Handling

    CERN Multimedia

    Garnier, J-C; Cherukuwada, S S

    2010-01-01

    LHCb aims to use its O(20000) CPU cores in the High Level Trigger (HLT) and its 120 TB Online storage system for data reprocessing during LHC shutdown periods. These periods can last between a few days and several weeks during the winter shutdown or even only a few hours during beam interfill gaps. These jobs run on files which are staged in from tape storage to the local storage buffer. The result are again one or more files. Efficient file writing and reading is essential for the performance of the system. Rather than using a traditional shared filesystem such as NFS or CIFS we have implemented a custom, light-weight, non-Posix file-system for the handling of these files. Streaming this filesystem for the data-access allows to obtain high performance, while at the same time keep the resource consumption low and add nice features not found in NFS such as high-availability, transparent failover of the read and write service. The writing part of this file-system is in successful use for the Online, real-time w...

  19. LHCb: The Front-End electronics for the LHCb scintillating fibres detector

    CERN Multimedia

    Chanal, H; Pillet, N

    2014-01-01

    The LHCb detector will be upgraded during the next LHC shutdown in 2018/19. The tracker system will have a major overhaul. Its components will be replaced with new technologies in order to cope with the increased hit occupancy and radiation environment. A detector made of scintillating fibres read out by silicon photomultipliers (SiPM) is studied for this upgrade. Even if this technology has proven to achieve high efficiency and spatial resolution, its integration within a LHC experiment bears new challenges. This detector will consist of 12 planes of 5 to 6 layers of 250 $\\mu$m fibres with an area of 5×6 m$^2$. Its lead to a total of 500k SiPM channels which need to will be read out at 40MHz. This talk gives an overview of the R&D status of the readout board and the PACIFIC chip. The readout board is connected to the SiPM on one side and to the experiment data-acquisition, experimental control system and services on the other side . The PACIFIC chip is a 128 channel ASIC which can be connected to one 12...

  20. LHCb: LHCb High Level Trigger design issues for post Long Stop 1 running

    CERN Multimedia

    Albrecht, J; Raven, G; Sokoloff, M D; Williams, M

    2013-01-01

    The LHCb High Level Trigger uses two stages of software running on an Event Filter Farm (EFF) to select events for offline reconstruction and analysis. The first stage (Hlt1) processes approximately 1 MHz of events accepted by a hardware trigger. In 2012, the second stage (Hlt2) wrote 5 kHz to permanent storage for later processing. Following the LHC's Long Stop 1 (anticipated for 2015), the machine energy will increase from 8 TeV in the center-of-mass to 13 TeV and the cross sections for beauty and charm are expected to grow proportionately. We plan to increase the Hlt2 output to 12 kHz, some for immediate offline processing, some for later offline processing, and some ready for immediate analysis. By increasing the absolute computing power of the EFF, and buffering data for processing between machine fills, we should be able to significantly increase the efficiency for signal while improving signal-to-background ratios. In this poster we will present several strategies under consideration and some of th...

  1. LHCb: The nightly build and test system for LCG AA and LHCb software

    CERN Multimedia

    Kruzelecki, K; Degaudenzi, H

    2009-01-01

    The core software stack both from the LCG Application Area and LHCb consists of more than 25 C++/Fortran/Python projects build for about 20 different configurations on Linux, Windows and MacOSX. To these projects, one can also add about 20 external software packages (Boost, Python, Qt, CLHEP, ...) which have also to be build for the same configurations. It order to reduce the time of the development cycle and increase the quality insurance, a framework has been developed for the daily (nightly actually) build and test of the software. Performing the build and the tests on several configurations and platform allows to increase the efficiency of the unit and integration tests. Main features: - flexible and fine grained setup (full, partial build) through a web interface - possibility to build several "slots" with different configurations - precise and highly granular reports on a web server - support for CMT projects (but not only) with their cross-dependencies. - scalable client -server architecture for the co...

  2. Improved organic scintillation detectors; Possibilites de perfectionnement des detecteurs organiques a scintillations; Usovershenstvovannye organicheskie stsintillyatsionnye detektory; Detectores organicos de centelleo perfeccionados

    Energy Technology Data Exchange (ETDEWEB)

    Birks, J B [University of Manchester, Manchester (United Kingdom)

    1962-04-15

    Equations have been derived for the practical scintillation efficiency (photo-electrons/MeV) of organic crystals and solutions in terms of molecular parameters and these have been applied to the more important scintillator systems, for photomultipliers with S11 (glass window) and S13 (quartz window) responses. The results suggest several improvements in current organic scintillation detector practice: the use of binary rather than ternary solutions; the use of quartz rather than glass windows; and the reconsideration of mixed crystal scintillators based on naphthalene. Improvements by factors of 2 or more in the figure of merit (practical efficiency/decay time) for fast-scintillation counting can be obtained. (author) [French] L'auteur a etabli des equations pour determiner le rendement de scintillation (photoelectrons/MeV) de cristaux et solutions organiques, en faisant intervenir des parametres moleculaires. Il a applique ces equations a des appareils a scintillations plus importantes pour determiner la reponse des photomultiplicateurs a fenetre en verre (S11) et a fenetre en quartz (S13). Les resultats obtenus ont fait apparaitre la possibilite d'ameliorer, a plusieurs egards, les detecteurs organiques a scintillations du type courant, par exemple en remplacant les solutions ternaires par des solutions binaires, les fenetres en verre par des fenetres en quartz, ou en reexaminant les possibilites offertes par les scintillateurs a cristaux mixtes a base de naphtalene. L'introduction de ces perfectionnements conduirait a une amelioration, du simple au double ou plus, du facteur de qualite (efficacite/temps de decroissance) des dispositifs de comptage a scintillations. (author) [Spanish] Se han establecido ecuaciones que permiten calcular el rendimiento practico de centelleo (fotoelectrones/MeV) de los cristales y soluciones organicos en funcion de parametros moleculares; estas ecuaciones han sido aplicadas a los sistemas de centelleo mas importantes, para

  3. Survey of boron detectors for thermal neutrons operating in the non proportional regime; Etude de detecteurs a bore pour neutrons thermiques fonctionnant en regime non proportionnel

    Energy Technology Data Exchange (ETDEWEB)

    Vacarie, J [Commissariat a l' Energie Atomique, 38 - Grenoble (France). Centre d' Etudes Nucleaires

    1968-07-01

    In gas counters, the alternative of directly detecting (i.e. without using the phenomenon of multiplication the charges ionized by the reaction {sup 10}B (n,{alpha}){sup 7}Li, offers many advantages as to the conception of such a detector. After examining the ionization phenomenon and deducing the characteristics of low-noise amplifiers, various prototypes are studied. - The D.I.N. 5/4, intended for fast neutrons detector, grants leave to have good isotropic proprieties thanks to its geometry and good sensitivity imputable to the BF{sub 3} filling pressure of 1 atm. - A flat counter (D.E.H. type), with plane and parallel electrodes, grants leave to work out a low height of influence, soil moisture measurer. The confrontation between various filling pressures (0.5, 1, 2, 3 atm.) points out the importance of attachment in BF{sub 3}. - Thanks to neutronic diffraction counter (C.D.N. 2 type) filled under 2 atm and parallelepiped, one can considerably reduce the weight of the goniometer protection, and lightly increase its sensitivity. - The results given by the experimental boron coating device have allowed to build a boron coating counter to be used in current collection. (author) [French] Dans les compteurs a gaz, la possibilite de detecter directement (c'est-a-dire sans utiliser le phenomene de multiplication) les charges ionisees lors de la reaction {sup 10}B (n,{alpha}){sup 7}Li offre de nombreux avantages pour la conception de detecteurs a bore. Apres avoir examine les phenomenes d'ionisation et en avoir deduit les caracteristiques de la chaine d'amplification faible-bruit, on etudie les differents prototypes developpes. - Le D.I.N. 5/4 destine a une sonde de neutrons rapides, permet d'avoir une bonne isotropie grace a sa geometrie et une bonne sensibilite due a sa pression de remplissage de 1 atm. en BF{sub 3}. - Un compteur plat (type D.E.H.) a electrodes planes et paralleles permet de realiser un humidimetre a faible hauteur d'influence. La comparaison de

  4. Absolute luminosity measurement at LHCb with beam-gas imaging

    CERN Document Server

    Barschel, C

    2013-01-01

    A novel technique to measure the absolute luminosity at the Large Hadron Collider (LHC) using beam-gas interactions has been successfully used in the LHCb experiment. A gas injection device (SMOG) has been installed in the LHCb experiment to increase the pressure around the interaction point during dedicated fills. The Beam-Gas Imaging method (BGI) has now the potential to surpass the accuracy of the commonly used *van der Meer scan* method (VDM). The technique has been used in 10 LHC fills during 2012 including and also provided a first luminosity measurement for proton-lead collisions. This talk presents the principles of the gas injection and the improvements reached with the increased pressure. Furthermore the gas injection increased the accuracy measurement of the so-called ghost charges and also intensities per bunch. Those uncertainties are becoming the dominating factor because the uncertainty on the total beam current have been reduced.

  5. Measurement of Charmonium Polarization with the LHCb Detector

    CERN Document Server

    Zhang, Yanxi

    In particle physics, quantum chromodynamics (QCD) is the theory used to describe the interaction of colored particles. Heavy quarkonium is the bound state of heavy quark and its anti-quark, and its production cross section and polarization can be used to test the theory models in the framework of QCD. The computation of the heavy quarkonium production cross section by color singlet mechanism (CSM) underestimates the experimental measurements, while results from the calculation of non-relativistic QCD (NRQCD) can describe experimental data very well. However, the NRQCD predicts that the $S$ wave heavy quarkonium is heavily transversely polarized in the large transverse momentum region, which is contrary to experimental observations. LHCb, dedicated for precision measurement in bottom and charm physics, is one of the experiments located at the Large Hadron Collider (LHC). The LHCb detector, which is a forward region spectrometer covering the pseudo rapidity range 2-5, has fine particle reconstruction and identi...

  6. Automated Grid Monitoring for LHCb through HammerCloud

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    The HammerCloud system is used by CERN IT to monitor the status of the Worldwide LHC Computing Grid (WLCG). HammerCloud automatically submits jobs to WLCG computing resources, closely replicating the workflow of Grid users (e.g. physicists analyzing data). This allows computation nodes and storage resources to be monitored, software to be tested (somewhat like continuous integration), and new sites to be stress tested with a heavy job load before commissioning. The HammerCloud system has been in use for ATLAS and CMS experiments for about five years. This summer's work involved porting the HammerCloud suite of tools to the LHCb experiment. The HammerCloud software runs functional tests and provides data visualizations. HammerCloud's LHCb variant is written in Python, using the Django web framework and Ganga/DIRAC for job management.

  7. VeloUT tracking for the LHCb Upgrade

    CERN Document Server

    Bowen, E

    2014-01-01

    This note describes track reconstruction in the LHCb tracking system upstream of the magnet, namely the VELO and UT sub-detectors. The implementation of the VeloUT algorithm and its performance in terms of track reconstruction efficiency, ghost rate and execution time per event are presented. The algorithm has been optimised for use in the Upgrade software trigger of LHCb. The momentum information obtained for the VeloUT tracks (due to a fringe magnetic field between the VELO and UT sub-detectors) can reduce the total execution time per event for the full tracking sequence. The performance of the tracking sequence with and without the use of VeloUT tracks is also presented.

  8. Exploring improvements to the LHCb ELOG electronic logbook

    CERN Document Server

    Leung, Philip; CERN. Geneva. PH Department

    2015-01-01

    ELOG, the electronic logbook used by LHCb, has been suffering from poor accessibility and slow performance. Investigating revealed that a combination of inefficient searches, caused mainly by frequent reads of files stored in NFS, and an inability for the server to handle concurrent operations were rendering the service unusable for up to a minute when users performed search or sort operations. By adding a minor patch to the ELOG source code, moving data to local storage and optimizing server configuration the project was able to reduce search-times for the largest of the logbooks being used at LHCb to 30\\% while also improving possibilities for future growth by allowing for concurrent use and accelerating the most common search-operations in a way which should stay consistent over extended time-periods.

  9. Exploring improvements to the LHCb ELOG electronic logbook

    CERN Document Server

    Leung, Philip

    2015-01-01

    ELOG, the electronic logbook used by LHCb, has been suffering from poor accessibility and slow performance. Investigating revealed that a combination of inefficient searches, caused mainly by frequent reads of files stored in NFS, and an inability for the server to handle concurrent operations were rendering the service unusable for up to a minute when users performed search or sort operations. By adding a minor patch to the ELOG source code, moving data to local storage and optimizing server configuration the project was able to reduce search-times for the largest of the logbooks being used at LHCb to 30% while also improving possibilities for future growth by allowing for concurrent use and accelerating the most common search-operations in a way which should stay consistent over extended time-periods.

  10. Evaluation of the Radiation Environment of the LHCb Experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00341385; Corti, Gloria

    The unprecedented radiation levels of the Large Hadron Collider (LHC) during high-energy proton-proton collisions will have an impact on the operation of its experiments’ detectors and electronics. LHCb, one of the 4 major LHC experiments, has started operation in 2009 and from 2011 onward it has been collecting data at and above its design luminosity. Detectors and associated detector electronics are prone to damage if the radiation levels exceed the expected values. It is essential to monitor the radiation environment of the experimental area and compare it with predictions obtained from simulation studies in order to assess the situation and take corrective action in case of need. Understanding the existing radiation environment will also provide important input to the planning of maintenance and for operation at upgrade luminosity. A set of radiation detectors has been installed in the LHCb experimental area to measure different aspects of its radiation environment. Passive dosimeters including Thermo-L...

  11. Position Reconstruction and Charge Distribution in LHCb VELO Silicon Sensors

    CERN Document Server

    Versloot, TW; Akiba, K; Artuso, M; Van Beuzekom, M; Borel, J; Bowcock, TJV; Buytaert, J; Collins, P; Dumps, R; Dwyer, L; Eckstein, D; Eklund, L; Ferro-Luzzi, M; Frei, R; Gersabek M; Haefeli, G; Hennessy, K; Huse, T; Jans, E; John, M; Ketel, TJ; Keune, A; Lastoviicka, T; Mountain, R; Neufeld, N; Parkes, C; Stone, S; Szumlak, T; Tobin, M; Van Lysebetten, A; Viret, S; De Vries, H; Wang, J

    2007-01-01

    In 2006, a partially equipped LHCb VELO detector half was characterised in a test beam experiment (Alignment Challenge and Detector Commissioning, ACDC3). The position reconstruction and resolution for 2-strip R-sensor clusters was studied as a function of strip pitch and track inclination on the sensor surface. The Charge Density Distribution (CDD) is derived from the weighted charge distribution. It becomes asymmetric for tracks non-perpendicular to the strip surface. It is shown that the asymmetric broadening of the CDD around the track intercept position results in a linear eta-function at higher angles (>6 degrees). The sensor spatial resolution is determined both using a linear weighted mean of strip charges, as well as a third-order polynomial approximation via a eta-correction. The experimental results are in agreement with previous simulations. Future studies are underway to determine the angle and pitch dependent parameters which will be implemented in the LHCb VELO cluster position software tools.

  12. Reconstruction of Cluster Positions in the LHCb Velo

    CERN Document Server

    Parkes, C; Szumlak, T

    2007-01-01

    This note describes the `Velo Cluster Position Tool'. This software is used in the GAUDI framework to estimate the hit position of a particle traversing the silicon sensors of the LHCb VELO and to estimate the uncertainty on this position. This estimate and its uncertainty are used in the LHCb track fit. The definition of the cluster centre is given and the baseline linear approximation method presented. The position error is strongly dependent on the angle of incidence of the particle on the silicon sensors measured perpendicularly to the strips -- known as the projected angle -- and on the silicon sensor pitch at the point of incidence, and is parametrised in terms of these variables. Pull plots are presented to show the quality of the current tuning implemented for simulation events.

  13. Measuring $CP$ violation with $\\Delta A_{CP}$ at LHCb

    CERN Document Server

    Pearce, Alex

    2014-01-01

    The control of systematic uncertainties is a key component of many analyses performed at the Large Hadron Collider, and will only become more important as more data are taken during Run II. Many of the CP measurements performed using the LHCb detector have statistical precisions below the per cent level, and so particular care must be taken in this area. One technique for dealing with the various production and detection asymmetries which can mask the physics asymmetry of interest, and increase the measurement’s systematic uncertainty, is $\\Delta A_{CP}$ . The application of $\\Delta A_{CP}$ in three separate LHCb analyses of $D^{0}$ and $\\Lambda_{b}^{0}$ decays will be discussed, along with prospects for applying the technique to $\\Lambda_{c}^{+}$ decays.

  14. The LHCb trigger and its performance in 2011

    International Nuclear Information System (INIS)

    Aaij, R; Beuzekom, M van; Coco, V; Albrecht, J; Alessio, F; Bonaccorsi, E; Brarda, L; Cattaneo, M; Chebbi, M; Clemencic, M; Closier, J; Amato, S; Aslanides, E; Cogan, J; Belyaev, I; Bonnefoy, R; Chanal, H; Deschamps, O; Callot, O; Vidal, X Cid

    2013-01-01

    This paper presents the design of the LHCb trigger and its performance on data taken at the LHC in 2011. A principal goal of LHCb is to perform flavour physics measurements, and the trigger is designed to distinguish charm and beauty decays from the light quark background. Using a combination of lepton identification and measurements of the particles' transverse momenta the trigger selects particles originating from charm and beauty hadrons, which typically fly a finite distance before decaying. The trigger reduces the roughly 11 MHz of bunch-bunch crossings that contain at least one inelastic pp interaction to 3 kHz. This reduction takes place in two stages; the first stage is implemented in hardware and the second stage is a software application that runs on a large computer farm. A data-driven method is used to evaluate the performance of the trigger on several charm and beauty decay modes.

  15. Disk storage management for LHCb based on Data Popularity estimator

    CERN Document Server

    INSPIRE-00545541; Charpentier, Philippe; Ustyuzhanin, Andrey

    2015-12-23

    This paper presents an algorithm providing recommendations for optimizing the LHCb data storage. The LHCb data storage system is a hybrid system. All datasets are kept as archives on magnetic tapes. The most popular datasets are kept on disks. The algorithm takes the dataset usage history and metadata (size, type, configuration etc.) to generate a recommendation report. This article presents how we use machine learning algorithms to predict future data popularity. Using these predictions it is possible to estimate which datasets should be removed from disk. We use regression algorithms and time series analysis to find the optimal number of replicas for datasets that are kept on disk. Based on the data popularity and the number of replicas optimization, the algorithm minimizes a loss function to find the optimal data distribution. The loss function represents all requirements for data distribution in the data storage system. We demonstrate how our algorithm helps to save disk space and to reduce waiting times ...

  16. Measurement of track reconstruction efficiency at LHCb

    CERN Multimedia

    Van Veghel, Maarten

    2018-01-01

    The precise evaluation of the tracking efficiencies is a crucial element for many physics analysis, especially those aiming at measuring production cross sections or branching fractions. In the LHCb experiment, several data-driven approaches have been conceived and continuously improved in order to provide a precise evaluation of the tracking efficiencies. They are mostly based on clean samples of muons, but the recent hints of lepton universality violation required the development of robust data-driven techniques specifically dedicated to electrons, in order to reduce the systematic uncertainties. In addition, special data streams have been recently put in place to collect and save the calibration samples selected in the LHCb software trigger for both muons and electrons, ensuring a prompt access right after the data has been collected.

  17. The Usage of ROOT in the LHCb Online System

    CERN Document Server

    Frank, M

    2013-01-01

    The online system in the LHCb experiment uses ROOT in various areas. ROOT is used in all processes participating in event data processing. The degree of usage varies quite significantly - from the very rudimentary usage of the ROOT plugin mechanism to fully equipped applications filling histograms with data describing online the detector status for monitoring purposes and the display of these data. An increasing number of processes uses the python binding offered by PyROOT to configure these processes. PyROOT also allows to efficiently and quickly manipulate certain corners of the experiment controls system where necessary. Beside these areas, where the LHCb online team advocated the usage of ROOT, in other areas other technologies were chosen. These deliberate choices like e.g. in the area of persistency of event data from particle collisions will be discussed.

  18. Generators, Calorimeter Trigger and J/ψ production at LHCb

    CERN Document Server

    Robbe, P

    This document presents results related to the preparation of the physics program ofLHCb: generator software development, calorimeter trigger commissioning and measurement of J/psi production. A detailed simulation is mandatory to developthe analysis tools needed for this program and a detailed generator framework hasbeen implemented which describes for example B mixing and CP violation in B decays in the LHCb hadronic environment. For hadronic decay modes, the trigger of the experiment is based at the first level on information provided by the calorimeters, and in particular the hadronic calorimeter. The large J/psi production cross-section at the LHC allows to perform, with the first data recorded, a measurement of the J/psi differential cross-section and to confront it with theoretical models to test QCD in the heavy quark sector.

  19. $B$ flavour tagging using charm decays at the LHCb experiment

    CERN Document Server

    Aaij, Roel; Adinolfi, Marco; Affolder, Anthony; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Anderson, Jonathan; Andreassi, Guido; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Aquines Gutierrez, Osvaldo; Archilli, Flavio; d'Argent, Philippe; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Batozskaya, Varvara; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Bel, Lennaert; Bellee, Violaine; Belloli, Nicoletta; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bertolin, Alessandro; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bien, Alexander; Bifani, Simone; Billoir, Pierre; Bird, Thomas; Birnkraut, Alex; Bizzeti, Andrea; Blake, Thomas; Blanc, Frédéric; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borghi, Silvia; Borsato, Martino; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Braun, Svende; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Brook, Nicholas; Buchanan, Emma; Bursche, Albert; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Campana, Pierluigi; Campora Perez, Daniel; Capriotti, Lorenzo; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carniti, Paolo; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cavallero, Giovanni; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu-Faye; Chiapolini, Nicola; Chrzaszcz, Marcin; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coco, Victor; Cogan, Julien; Cogneras, Eric; Cogoni, Violetta; Cojocariu, Lucian; Collazuol, Gianmaria; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombes, Matthew; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Crocombe, Andrew; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Dall'Occo, Elena; Dalseno, Jeremy; David, Pieter; Davis, Adam; De Bruyn, Kristof; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Simone, Patrizia; Dean, Cameron Thomas; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Déléage, Nicolas; Demmer, Moritz; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Dey, Biplab; Di Canto, Angelo; Di Ruscio, Francesco; Dijkstra, Hans; Donleavy, Stephanie; Dordei, Francesca; Dorigo, Mirco; Dosil Suárez, Alvaro; Dossett, David; Dovbnya, Anatoliy; Dreimanis, Karlis; Dufour, Laurent; Dujany, Giulio; Dupertuis, Frederic; Durante, Paolo; Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; Easo, Sajan; Egede, Ulrik; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; El Rifai, Ibrahim; Elsasser, Christian; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Färber, Christian; Farinelli, Chiara; Farley, Nathanael; Farry, Stephen; Fay, Robert; Ferguson, Dianne; Fernandez Albor, Victor; Ferrari, Fabio; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fiore, Marco; Fiorini, Massimiliano; Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fohl, Klaus; Fol, Philip; Fontana, Marianna; Fontanelli, Flavio; Forty, Roger; Francisco, Oscar; Frank, Markus; Frei, Christoph; Frosini, Maddalena; Fu, Jinlin; Furfaro, Emiliano; Gallas Torreira, Abraham; Galli, Domenico; Gallorini, Stefano; Gambetta, Silvia; Gandelman, Miriam; Gandini, Paolo; Gao, Yuanning; García Pardiñas, Julián; Garra Tico, Jordi; Garrido, Lluis; Gascon, David; Gaspar, Clara; Gauld, Rhorry; Gavardi, Laura; Gazzoni, Giulio; Gerick, David; Gersabeck, Evelina; Gersabeck, Marco; Gershon, Timothy; Ghez, Philippe; Gianelle, Alessio; Gianì, Sebastiana; Gibson, Valerie; Girard, Olivier Göran; Giubega, Lavinia-Helena; Gligorov, V.V.; Göbel, Carla; Golubkov, Dmitry; Golutvin, Andrey; Gomes, Alvaro; Gotti, Claudio; Grabalosa Gándara, Marc; Graciani Diaz, Ricardo; Granado Cardoso, Luis Alberto; Graugés, Eugeni; Graverini, Elena; Graziani, Giacomo; Grecu, Alexandru; Greening, Edward; Gregson, Sam; Griffith, Peter; Grillo, Lucia; Grünberg, Oliver; Gui, Bin; Gushchin, Evgeny; Guz, Yury; Gys, Thierry; Hadavizadeh, Thomas; Hadjivasiliou, Christos; Haefeli, Guido; Haen, Christophe; Haines, Susan; Hall, Samuel; Hamilton, Brian; Han, Xiaoxue; Hansmann-Menzemer, Stephanie; Harnew, Neville; Harnew, Samuel; Harrison, Jonathan; He, Jibo; Head, Timothy; Heijne, Veerle; Hennessy, Karol; Henrard, Pierre; Henry, Louis; Hernando Morata, Jose Angel; van Herwijnen, Eric; Heß, Miriam; Hicheur, Adlène; Hill, Donal; Hoballah, Mostafa; Hombach, Christoph; Hulsbergen, Wouter; Humair, Thibaud; Hussain, Nazim; Hutchcroft, David; Hynds, Daniel; Idzik, Marek; Ilten, Philip; Jacobsson, Richard; Jaeger, Andreas; Jalocha, Pawel; Jans, Eddy; Jawahery, Abolhassan; Jing, Fanfan; John, Malcolm; Johnson, Daniel; Jones, Christopher; Joram, Christian; Jost, Beat; Jurik, Nathan; Kandybei, Sergii; Kanso, Walaa; Karacson, Matthias; Karbach, Moritz; Karodia, Sarah; Kecke, Matthieu; Kelsey, Matthew; Kenyon, Ian; Kenzie, Matthew; Ketel, Tjeerd; Khanji, Basem; Khurewathanakul, Chitsanu; Klaver, Suzanne; Klimaszewski, Konrad; Kochebina, Olga; Kolpin, Michael; Komarov, Ilya; Koopman, Rose; Koppenburg, Patrick; Kozeiha, Mohamad; Kravchuk, Leonid; Kreplin, Katharina; Kreps, Michal; Krocker, Georg; Krokovny, Pavel; Kruse, Florian; Krzemien, Wojciech; Kucewicz, Wojciech; Kucharczyk, Marcin; Kudryavtsev, Vasily; Kuonen, Axel Kevin; Kurek, Krzysztof; Kvaratskheliya, Tengiz; Lacarrere, Daniel; Lafferty, George; Lai, Adriano; Lambert, Dean; Lanfranchi, Gaia; Langenbruch, Christoph; Langhans, Benedikt; Latham, Thomas; Lazzeroni, Cristina; Le Gac, Renaud; van Leerdam, Jeroen; Lees, Jean-Pierre; Lefèvre, Regis; Leflat, Alexander; Lefrançois, Jacques; Leroy, Olivier; Lesiak, Tadeusz; Leverington, Blake; Li, Yiming; Likhomanenko, Tatiana; Liles, Myfanwy; Lindner, Rolf; Linn, Christian; Lionetto, Federica; Liu, Bo; Liu, Xuesong; Loh, David; Longstaff, Iain; Lopes, Jose; Lucchesi, Donatella; Lucio Martinez, Miriam; Luo, Haofei; Lupato, Anna; Luppi, Eleonora; Lupton, Oliver; Lusiani, Alberto; Machefert, Frederic; Maciuc, Florin; Maev, Oleg; Maguire, Kevin; Malde, Sneha; Malinin, Alexander; Manca, Giulia; Mancinelli, Giampiero; Manning, Peter Michael; Mapelli, Alessandro; Maratas, Jan; Marchand, Jean François; Marconi, Umberto; Marin Benito, Carla; Marino, Pietro; Marks, Jörg; Martellotti, Giuseppe; Martin, Morgan; Martinelli, Maurizio; Martinez Santos, Diego; Martinez Vidal, Fernando; Martins Tostes, Danielle; Massafferri, André; Matev, Rosen; Mathad, Abhijit; Mathe, Zoltan; Matteuzzi, Clara; Mauri, Andrea; Maurin, Brice; Mazurov, Alexander; McCann, Michael; McCarthy, James; McNab, Andrew; McNulty, Ronan; Meadows, Brian; Meier, Frank; Meissner, Marco; Melnychuk, Dmytro; Merk, Marcel; Michielin, Emanuele; Milanes, Diego Alejandro; Minard, Marie-Noelle; Mitzel, Dominik Stefan; Molina Rodriguez, Josue; Monroy, Ignacio Alberto; Monteil, Stephane; Morandin, Mauro; Morawski, Piotr; Mordà, Alessandro; Morello, Michael Joseph; Moron, Jakub; Morris, Adam Benjamin; Mountain, Raymond; Muheim, Franz; Muller, Dominik; Müller, Janine; Müller, Katharina; Müller, Vanessa; Mussini, Manuel; Muster, Bastien; Naik, Paras; Nakada, Tatsuya; Nandakumar, Raja; Nandi, Anita; Nasteva, Irina; Needham, Matthew; Neri, Nicola; Neubert, Sebastian; Neufeld, Niko; Neuner, Max; Nguyen, Anh Duc; Nguyen, Thi-Dung; Nguyen-Mau, Chung; Niess, Valentin; Niet, Ramon; Nikitin, Nikolay; Nikodem, Thomas; Ninci, Daniele; Novoselov, Alexey; O'Hanlon, Daniel Patrick; Oblakowska-Mucha, Agnieszka; Obraztsov, Vladimir; Ogilvy, Stephen; Okhrimenko, Oleksandr; Oldeman, Rudolf; Onderwater, Gerco; Osorio Rodrigues, Bruno; Otalora Goicochea, Juan Martin; Otto, Adam; Owen, Patrick; Oyanguren, Maria Aranzazu; Palano, Antimo; Palombo, Fernando; Palutan, Matteo; Panman, Jacob; Papanestis, Antonios; Pappagallo, Marco; Pappalardo, Luciano; Pappenheimer, Cheryl; Parkes, Christopher; Passaleva, Giovanni; Patel, Girish; Patel, Mitesh; Patrignani, Claudia; Pearce, Alex; Pellegrino, Antonio; Penso, Gianni; Pepe Altarelli, Monica; Perazzini, Stefano; Perret, Pascal; Pescatore, Luca; Petridis, Konstantinos; Petrolini, Alessandro; Petruzzo, Marco; Picatoste Olloqui, Eduardo; Pietrzyk, Boleslaw; Pilař, Tomas; Pinci, Davide; Pistone, Alessandro; Piucci, Alessio; Playfer, Stephen; Plo Casasus, Maximo; Poikela, Tuomas; Polci, Francesco; Poluektov, Anton; Polyakov, Ivan; Polycarpo, Erica; Popov, Alexander; Popov, Dmitry; Popovici, Bogdan; Potterat, Cédric; Price, Eugenia; Price, Joseph David; Prisciandaro, Jessica; Pritchard, Adrian; Prouve, Claire; Pugatch, Valery; Puig Navarro, Albert; Punzi, Giovanni; Qian, Wenbin; Quagliani, Renato; Rachwal, Bartolomiej; Rademacker, Jonas; Rama, Matteo; Rangel, Murilo; Raniuk, Iurii; Rauschmayr, Nathalie; Raven, Gerhard; Redi, Federico; Reichert, Stefanie; Reid, Matthew; dos Reis, Alberto; Ricciardi, Stefania; Richards, Sophie; Rihl, Mariana; Rinnert, Kurt; Rives Molina, Vincente; Robbe, Patrick; Rodrigues, Ana Barbara; Rodrigues, Eduardo; Rodriguez Lopez, Jairo Alexis; Rodriguez Perez, Pablo; Roiser, Stefan; Romanovsky, Vladimir; Romero Vidal, Antonio; Ronayne, John William; Rotondo, Marcello; Rouvinet, Julien; Ruf, Thomas; Ruiz, Hugo; Ruiz Valls, Pablo; Saborido Silva, Juan Jose; Sagidova, Naylya; Sail, Paul; Saitta, Biagio; Salustino Guimaraes, Valdir; Sanchez Mayordomo, Carlos; Sanmartin Sedes, Brais; Santacesaria, Roberta; Santamarina Rios, Cibran; Santimaria, Marco; Santovetti, Emanuele; Sarti, Alessio; Satriano, Celestina; Satta, Alessia; Saunders, Daniel Martin; Savrina, Darya; Schiller, Manuel; Schindler, Heinrich; Schlupp, Maximilian; Schmelling, Michael; Schmelzer, Timon; Schmidt, Burkhard; Schneider, Olivier; Schopper, Andreas; Schubiger, Maxime; Schune, Marie Helene; Schwemmer, Rainer; Sciascia, Barbara; Sciubba, Adalberto; Semennikov, Alexander; Serra, Nicola; Serrano, Justine; Sestini, Lorenzo; Seyfert, Paul; Shapkin, Mikhail; Shapoval, Illya; Shcheglov, Yury; Shears, Tara; Shekhtman, Lev; Shevchenko, Vladimir; Shires, Alexander; Siddi, Benedetto Gianluca; Silva Coutinho, Rafael; Silva de Oliveira, Luiz Gustavo; Simi, Gabriele; Sirendi, Marek; Skidmore, Nicola; Skillicorn, Ian; Skwarnicki, Tomasz; Smith, Edmund; Smith, Eluned; Smith, Iwan Thomas; Smith, Jackson; Smith, Mark; Snoek, Hella; Sokoloff, Michael; Soler, Paul; Soomro, Fatima; Souza, Daniel; Souza De Paula, Bruno; Spaan, Bernhard; Spradlin, Patrick; Sridharan, Srikanth; Stagni, Federico; Stahl, Marian; Stahl, Sascha; Stefkova, Slavorima; Steinkamp, Olaf; Stenyakin, Oleg; Stevenson, Scott; Stoica, Sabin; Stone, Sheldon; Storaci, Barbara; Stracka, Simone; Straticiuc, Mihai; Straumann, Ulrich; Sun, Liang; Sutcliffe, William; Swientek, Krzysztof; Swientek, Stefan; Syropoulos, Vasileios; Szczekowski, Marek; Szczypka, Paul; Szumlak, Tomasz; T'Jampens, Stephane; Tayduganov, Andrey; Tekampe, Tobias; Teklishyn, Maksym; Tellarini, Giulia; Teubert, Frederic; Thomas, Christopher; Thomas, Eric; van Tilburg, Jeroen; Tisserand, Vincent; Tobin, Mark; Todd, Jacob; Tolk, Siim; Tomassetti, Luca; Tonelli, Diego; Topp-Joergensen, Stig; Torr, Nicholas; Tournefier, Edwige; Tourneur, Stephane; Trabelsi, Karim; Tran, Minh Tâm; Tresch, Marco; Trisovic, Ana; Tsaregorodtsev, Andrei; Tsopelas, Panagiotis; Tuning, Niels; Ukleja, Artur; Ustyuzhanin, Andrey; Uwer, Ulrich; Vacca, Claudia; Vagnoni, Vincenzo; Valenti, Giovanni; Vallier, Alexis; Vazquez Gomez, Ricardo; Vazquez Regueiro, Pablo; Vázquez Sierra, Carlos; Vecchi, Stefania; Velthuis, Jaap; Veltri, Michele; Veneziano, Giovanni; Vesterinen, Mika; Viaud, Benoit; Vieira, Daniel; Vieites Diaz, Maria; Vilasis-Cardona, Xavier; Vollhardt, Achim; Volyanskyy, Dmytro; Voong, David; Vorobyev, Alexey; Vorobyev, Vitaly; Voß, Christian; de Vries, Jacco; Waldi, Roland; Wallace, Charlotte; Wallace, Ronan; Walsh, John; Wandernoth, Sebastian; Wang, Jianchun; Ward, David; Watson, Nigel; Websdale, David; Weiden, Andreas; Whitehead, Mark; Wilkinson, Guy; Wilkinson, Michael; Williams, Mark Richard James; Williams, Matthew; Williams, Mike; Williams, Timothy; Wilson, Fergus; Wimberley, Jack; Wishahi, Julian; Wislicki, Wojciech; Witek, Mariusz; Wormser, Guy; Wotton, Stephen; Wright, Simon; Wyllie, Kenneth; Xie, Yuehong; Xu, Zhirui; Yang, Zhenwei; Yu, Jiesheng; Yuan, Xuhao; Yushchenko, Oleg; Zangoli, Maria; Zavertyaev, Mikhail; Zhang, Liming; Zhang, Yanxi; Zhelezov, Alexey; Zhokhov, Anatoly; Zhong, Liang; Zucchelli, Stefano

    2015-10-05

    An algorithm is described for tagging the flavour content at production of neutral $B$ mesons in the LHCb experiment. The algorithm exploits the correlation of the flavour of a $B$ meson with the charge of a reconstructed secondary charm hadron from the decay of the other $b$ hadron produced in the proton-proton collision. Charm hadron candidates are identified in a number of fully or partially reconstructed Cabibbo-favoured decay modes. The algorithm is calibrated on the self-tagged decay modes $B^+ \\to J/\\psi \\, K^+$ and $B^0 \\to J/\\psi \\, K^{*0}$ using $3.0\\mathrm{\\,fb}^{-1}$ of data collected by the LHCb experiment at $pp$ centre-of-mass energies of $7\\mathrm{\\,TeV}$ and $8\\mathrm{\\,TeV}$. Its tagging power on these samples of $B \\to J/\\psi \\, X$ decays is $(0.30 \\pm 0.01 \\pm 0.01) \\%$.

  20. Optimization of the HLT Resource Consumption in the LHCb Experiment

    International Nuclear Information System (INIS)

    Frank, M; Gaspar, C; Herwijnen, E v.; Jost, B; Neufeld, N; Schwemmer, R

    2012-01-01

    Today's computing elements for software based high level trigger processing (HLT) are based on nodes with multiple cores. Using process based parallelization to filter particle collisions from the LHCb experiment on such nodes leads to expensive consumption of memory and hence significant cost increase. In the following an approach is presented to both minimize the resource consumption of the filter applications and to reduce the startup time. Described is the duplication of threads and the handling of files open in read-write mode when duplicating filter processes and the possibility to bootstrap the event filter applications directly from preconfigured checkpoint files. This led to a reduced memory consumption of roughly 60% in the nodes of the LHCb HLT farm and an improved startup time of a factor 10.

  1. LHCb's Time-Real Alignment in RunII

    CERN Multimedia

    Batozskaya, Varvara

    2015-01-01

    LHCb has introduced a novel real-time detector alignment and calibration strategy for LHC Run 2. Data collected at the start of the fill will be processed in a few minutes and used to update the alignment, while the calibration constants will be evaluated for each run. This procedure will improve the quality of the online alignment. Critically, this new real-time alignment and calibration procedure allows identical constants to be used in the online and offline reconstruction, thus improving the correlation between triggered and offline selected events. This offers the opportunity to optimise the event selection in the trigger by applying stronger constraints. The required computing time constraints are met thanks to a new dedicated framework using the multi-core farm infrastructure for the trigger. The motivation for a real-time alignment and calibration of the LHCb detector is discussed from both the operational and physics performance points of view. Specific challenges of this novel configur...

  2. LHCb Data Management: consistency, integrity and coherence of data

    CERN Document Server

    Bargiotti, Marianne

    2007-01-01

    The Large Hadron Collider (LHC) at CERN will start operating in 2007. The LHCb experiment is preparing for the real data handling and analysis via a series of data challenges and production exercises. The aim of these activities is to demonstrate the readiness of the computing infrastructure based on WLCG (Worldwide LHC Computing Grid) technologies, to validate the computing model and to provide useful samples of data for detector and physics studies. DIRAC (Distributed Infrastructure with Remote Agent Control) is the gateway to WLCG. The Dirac Data Management System (DMS) relies on both WLCG Data Management services (LCG File Catalogues, Storage Resource Managers and File Transfer Service) and LHCb specific components (Bookkeeping Metadata File Catalogue). Although the Dirac DMS has been extensively used over the past years and has proved to achieve a high grade of maturity and reliability, the complexity of both the DMS and its interactions with numerous WLCG components as well as the instability of facilit...

  3. Système de PLC pour la supervision de la distribution basse tension des expériences ALICE et LHCb

    CERN Document Server

    Burdet, G

    2004-01-01

    Le groupe TS/EL étudie et réalise la distribution électrique basse tension pour alimenter les racks contenant l'électronique associée aux détecteurs dans les zones expérimentales du LHC. La distribution basse tension utilisera des tableaux récupérés des expériences du LEP pour ALICE et LHCb et un système basé sur des gaines CANALIS pour ATLAS et CMS. L'ensemble de la distribution électrique basse tension sera surveillée et contrôlée par l'intermédiaire de systèmes à base de PLC. Ce papier décrit l'infrastructure de supervision proposée pour ALICE et LHCb et son intégration au CERN Electrical Network Supervisor (ENS) et au Detector Control System (DCS).

  4. New results on Bs mixing and CP violation from LHCb

    CERN Multimedia

    CERN. Geneva

    2013-01-01

    Oscillation effects in the Bs meson system provide a window on physics beyond the Standard Model. The latest results from LHCb on the mass and width differences between the two physical eigenstates, and the CP violating phase measured in the Bs -> J/psi phi decay channel are presented. In addition, results of a first study of the CP violating phase in the penguin-dominated Bs -> phiphi decays are shown.

  5. Jet reconstruction and heavy jet tagging at LHCb

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    The jet reconstruction and the heavy jet flavour tagging at LHCb will be discussed with focus on the last published measurements such as the measurement of forward tt, W+bb and W+cc production in pp collisions at √s=8 TeV and the search for the SM Higgs boson decaying in bbbar or ccbar in association to W or Z boson.

  6. W, Z and top production measurements at LHCb

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00258880

    2018-01-01

    Due to its unique pseudorapidity coverage between 2 and 5 and excellent performance, the LHCb detector allows for complementary probe of electroweak and QCD processes to those at ATLAS and CMS experiments. Studies of electroweak boson and top production provide important probes of the Standard Model at LHC energies and constrain parton distribution functions. The recent results on theW, Z and top production are briefly summarized in the present proceedings.

  7. $B_{s}\\to J/\\psi ~\\phi$ at LHCb

    CERN Document Server

    Fitzpatrick, C

    2009-01-01

    CP violation in the interference between mixing and decay of $B_{s}\\to J/\\psi ~\\phi$ is characterised by the weak phase $\\Phi$ which is predicted to be $-2\\beta_s$ in the SM. A deviation in $\\Phi$ from $-2\\beta_s$ is an indicator of new physics entering into $B_{s}/\\bar{B}_{s}$ mixing. LHCb will yield a competitive measurement of the phase $\\Phi$ in less than one year of data taking.

  8. Prospects for |V$_{ub}$| measurements at LHCb

    CERN Multimedia

    Stefkova, Slavomira

    2016-01-01

    Precise measurements of the quark coupling strength, $|V_{ub}|$, the least well known CKM element, allow a strong test of the unitarity of the CKM matrix. Previous measurements using exclusive and inclusive methods have resulted in values of $|V_{ub}|$ which are 3$\\sigma$ apart. The first measurement of $|V_{ub}|$ at LHCb confirmed this tension using the $\\Lambda^{0}_{b} \\rightarrow p \\mu^{-} \\overline{\

  9. Selected Measurements of Rare Decays at the LHCb Experiment

    CERN Document Server

    Pikies, Malgorzata

    2016-01-01

    Experimental results of rare decays B$^0$$\\to K*^0\\mu\\mu$, B$^0 \\to K*^0$ee, $\\Lambda_b\\to\\Lambda\\mu\\mu$ and B$^0_s$ governed by Flavour Changing Neutral Current transitions are discussed in this paper. The angular distributions and differential branching fractions measurements were performed using data corresponding to an integrated luminosity of 3:0 fb$^{-1}$ collected at the LHCb experiment.

  10. LHC(ATLAS, CMS, LHCb) Run 2 commissioning status

    CERN Document Server

    Zimmermann, Stephanie; The ATLAS collaboration

    2015-01-01

    After a very successful run-1, the LHC accelerator and the LHC experiments had undergone intensive consolidation, maintenance and upgrade activities during the last 2 years in what has become known as Long-Shutdown-1 (LS1). LS1 ended in February this year, with beams back in the LHC since Easter. This talk will give a summary on the major shutdown activities of ATLAS, CMS and LHCb and review the status of commissioning for run-2 physics data taking.

  11. LHC-B trigger and data acquisition progress report

    CERN Document Server

    Dijkstra, H; Harris, Frank

    1997-01-01

    97-05 This report describes the progress since the Letter of Intent [1] in the development of the trigger and data acquisition system for LHC-B. The basic philosophy has changed significantly, with the proposal to implement tracking and vertex topology triggers in specialised hardware. This will be at an additional trigger level, giving 4 levels in total. We present details of the new proposal, together with preliminary requirements estimates, and some simulation results.

  12. Measurement of Indirect CP Violation in Charm at LHCb

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00342046

    This thesis describes two pieces of work. The first is a study of the resolution of the LHCb vertex locator throughout Run 1. The second comprises analyses to measure the charm mixing and $CP$ violation observables $A_{\\Gamma}$ and $y_{CP}$. An estimate of the resolution of the LHCb vertex locator is required for use in the track fits. A method to measure the resolution with collision data has been developed and tested. The performance of the sub-detector throughout Run 1 of the LHC has been assessed. A significant degrading of the resolution has been seen. The effects of this on the track reconstruction has been examined with little change in the measured quantities being observed. The measurement of indirect $CP$ violation in neutral $D$ meson transitions has been measured through the observables $A_{\\Gamma}$ and $y_{CP}$, using $fb^{-1}$ of $pp$ collisions with a centre of mass energy $7 TeV$, collected by the LHCb detector in 2011. $A_{\\Gamma}$ describes the $CP$ asymmetry of the lifetime of the $D^0$ dec...

  13. Latest LHCb measurements of Electroweak Boson Production in Run-1

    CERN Document Server

    CERN. Geneva

    2015-01-01

    We present the latest LHCb measurements of forward Electroweak Boson Production using proton-proton collisions recorded in LHC Run-1. The seminar shall discuss measurements of the 8 TeV W & Z boson production cross-sections. These results make use of LHCb's excellent integrated luminosity determination to provide constraints on the parton distribution functions which describe the inner structure of the proton. These LHCb measurements probe a region of phase space at low Bjorken-x where the other LHC experiments have limited sensitivity. We also present measurements of cross-section ratios, and ratios of results in 7 TeV and 8 TeV proton-proton collisions. These results provide precision tests of the Standard Model. The seminar shall also present a measurement of the forward-backward asymmetry (A_FB) in Z boson decays to two muons. This result allows for precision tests of the coupling of the Z boson to left and right handed particles, providing sensitivity to the effective weak mixing angle (...

  14. Long lived neutralinos at LHCb in GMSB models

    Energy Technology Data Exchange (ETDEWEB)

    Magro, Mauricio B. [Fundacao Santo Andre (FSA), SP (Brazil); Campos, Fernando de [Universidade Estadual Paulista Julio de Mesquita Filho (FEG/UNESP), SP (Brazil). Fac. de Engenharia de Guaratingueta; Eboli, Oscar [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Fisica

    2011-07-01

    Full text: We study the signatures of long-lived neutralinos at the LHCb detector considering that SUSY is broken via gauge mediation. In such kind of models the LSP is the gravitino and, most of the time, the first neutralino is the NLSP. Since the coupling of neutralino and gravitino is usually small, the neutralino lives long enough to produce a displaced vertex within the LHC detectors. Using the Spheno code we show that, is GMSB models, a sizeable fraction of the lightest neutralinos, around 10% of the time, decays into a Z-boson plus a gravitino, leaving as a signal charged particles coming from a displaced vertex plus missing energy. Specifically, we focus on the case of a neutralino NLSP decaying to Z and gravitino within the context of Gauge Meditated Symmetry Breaking with the Z-bosons further decaying into charged leptons to leave a clean signature. We point out that events from Z {yields} {iota}{sup +}{iota}{sup -} can be used for detailed kinematic reconstruction. In particular, we examine the prospects for detailed event study at LHCb using a toy detector with help from Pythia code. Finally, we demonstrate that there is a region in parameter space where the LHCb could potentially discover new physics searching for displaced vertices containing {iota}{sup +}{iota}{sup -} plus missing energy channel. (author)

  15. LHCb Kalman filter cross architecture studies

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00388548

    2017-01-01

    The 2020 upgrade of the LHCb detector will vastly increase the rate of collisions the Online system needs to process in software, in order to filter events in real time. 30 million collisions per second will pass through a selection chain, where each step is executed conditional to its prior acceptance. The Kalman filter is a fit applied to all reconstructed tracks which, due to its time characteristics and early execution in the selection chain, consumes 40% of the whole reconstruction time in the current trigger software. This makes the Kalman filter a time-critical component as the LHCb trigger evolves into a full software trigger in the Upgrade. I present a new Kalman filter algorithm for LHCb that can efficiently make use of any kind of SIMD processor, and its design is explained in depth. Performance benchmarks are compared between a variety of hardware architectures, including x86_64 and Power8, and the Intel Xeon Phi accelerator, and the suitability of said architectures to efficiently perform th...

  16. Prospects for time-dependent asymmetries at LHCb

    CERN Document Server

    Dupertuis, Frédéric

    2013-01-01

    LHCb has been acquiring physics data since 2010 and recorded about 0.04 fb$^{-1}$ in 2010 and 1.1 fb$^{-1}$ in 2011 at center-of-mass energy $\\sqrt{s}$ of 7 TeV. In 2012, it is projected to record 2.2 $^{-1}$ at an energy of $\\sqrt{s}$ = 8 TeV with a nominal instantaneous luminosity of $\\cal{L}$ = 4 x 10$^{32}$ cm $^{-2}$ s$^{-1}$, before a long shutdown of almost two years. The data taking is expected to resume by the end of 2014 at $\\sqrt{s}$ = 13 – 14 TeV, before a second long shutdown in 2018 when the upgraded LHCb detector components will be installed. Since the $b\\bar{b}$ cross section depends almost linearly on $\\sqrt{s}$, this will lead to an increase of about 100% in $b\\bar{b}$ pairs yield at $\\sqrt{s}$ = 14 compared to $\\sqrt{s}$ = 7. By 2018, a data sample larger than 8 fb$^{-1}$ is expected to have been recorded, leading to an increase of about a factor four in statistical power with respect to the 1 fb$^{-1}$ sample recorded at $\\sqrt{s}$ = 7 TeV. The LHCb upgrade [2] is designed to take data u...

  17. Software alignment of the LHCb Outer Tracker chambers

    Energy Technology Data Exchange (ETDEWEB)

    Deissenroth, Marc

    2010-04-21

    This work presents an alignment algorithm that was developed to precisely determine the positions of the LHCb Outer Tracker detector elements. The algorithm is based on the reconstruction of tracks and exploits that misalignments of the detector change the residual between a measured hit and the reconstructed track. It considers different levels of granularities of the Outer Tracker geometry and fully accounts for correlations of all elements which are imposed by particle trajectories. In extensive tests, simulated shifts and rotations for different levels of the detector granularity have been used as input to the track reconstruction and alignment procedure. With about 260 000 tracks the misalignments are recovered with a statistical precision of O(10 - 100 {mu}m) for the translational degrees of freedom and of O(10{sup -2} - 10{sup -1} mrad) for rotations. A study has been performed to determine the impact of Outer Tracker misalignments on the performance of the track reconstruction algorithms. It shows that the achieved statistical precision does not decrease the track reconstruction performance in a significant way. During the commissioning of the LHCb detector, cosmic ray muon events have been collected. The events have been analysed and used for the first alignment of the 216 Outer Tracker modules. The module positions have been determined within {proportional_to} 90 {mu}m. The developed track based alignment algorithm has demonstrated its reliability and is one of the core algorithms which are used for the precise determination of the positions of the LHCb Outer Tracker elements. (orig.)

  18. Management, Optimization and Evolution of the LHCb Online Network

    CERN Document Server

    Liu, G; Savriè, M; Neufeld, N

    2010-01-01

    The LHCb experiment is one of the four large particle detectors operated at the Large Hadron Collider (LHC) at CERN. It is a forward single-arm spectrometer dedicated to test the Standard Model through precision measurements of Charge-Parity (CP) violation and rare decays in the b quark sector. The LHCb experiment will operate at a luminosity of 2 x 10$^{32}cm^{-2}s^{-1}$, the proton-proton bunch crossings rate will be approximately 10 MHz. To select the interesting events, a two-level trigger scheme is applied: the first level trigger (L0) and the high level trigger (HLT). The L0 trigger is implemented in custom hardware, while HLT is implemented in software running on the CPUs of the Event Filter Farm (EFF). The L0 trigger rate is limited to about 1 MHz, and the event size for each event is about 35 kByte. It is a big challenge to handle the resulting data rate (35GByte/s). The online system is a key part of the LHCb experiment, providing all the IT services. It consists of three major components: the Data ...

  19. Software alignment of the LHCb Outer Tracker chambers

    International Nuclear Information System (INIS)

    Deissenroth, Marc

    2010-01-01

    This work presents an alignment algorithm that was developed to precisely determine the positions of the LHCb Outer Tracker detector elements. The algorithm is based on the reconstruction of tracks and exploits that misalignments of the detector change the residual between a measured hit and the reconstructed track. It considers different levels of granularities of the Outer Tracker geometry and fully accounts for correlations of all elements which are imposed by particle trajectories. In extensive tests, simulated shifts and rotations for different levels of the detector granularity have been used as input to the track reconstruction and alignment procedure. With about 260 000 tracks the misalignments are recovered with a statistical precision of O(10 - 100 μm) for the translational degrees of freedom and of O(10 -2 - 10 -1 mrad) for rotations. A study has been performed to determine the impact of Outer Tracker misalignments on the performance of the track reconstruction algorithms. It shows that the achieved statistical precision does not decrease the track reconstruction performance in a significant way. During the commissioning of the LHCb detector, cosmic ray muon events have been collected. The events have been analysed and used for the first alignment of the 216 Outer Tracker modules. The module positions have been determined within ∝ 90 μm. The developed track based alignment algorithm has demonstrated its reliability and is one of the core algorithms which are used for the precise determination of the positions of the LHCb Outer Tracker elements. (orig.)

  20. Long lived neutralinos at LHCb in GMSB models

    International Nuclear Information System (INIS)

    Magro, Mauricio B.; Campos, Fernando de; Eboli, Oscar

    2011-01-01

    Full text: We study the signatures of long-lived neutralinos at the LHCb detector considering that SUSY is broken via gauge mediation. In such kind of models the LSP is the gravitino and, most of the time, the first neutralino is the NLSP. Since the coupling of neutralino and gravitino is usually small, the neutralino lives long enough to produce a displaced vertex within the LHC detectors. Using the Spheno code we show that, is GMSB models, a sizeable fraction of the lightest neutralinos, around 10% of the time, decays into a Z-boson plus a gravitino, leaving as a signal charged particles coming from a displaced vertex plus missing energy. Specifically, we focus on the case of a neutralino NLSP decaying to Z and gravitino within the context of Gauge Meditated Symmetry Breaking with the Z-bosons further decaying into charged leptons to leave a clean signature. We point out that events from Z → ι + ι - can be used for detailed kinematic reconstruction. In particular, we examine the prospects for detailed event study at LHCb using a toy detector with help from Pythia code. Finally, we demonstrate that there is a region in parameter space where the LHCb could potentially discover new physics searching for displaced vertices containing ι + ι - plus missing energy channel. (author)

  1. The LHCb VERTEX LOCATOR performance and VERTEX LOCATOR upgrade

    International Nuclear Information System (INIS)

    Rodríguez Pérez, P

    2012-01-01

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

  2. The Software Architecture of the LHCb High Level Trigger

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    The LHCb experiment is a spectrometer dedicated to the study of heavy flavor at the LHC. The rate of proton-proton collisions at the LHC is 15 MHz, but disk space limitations mean that only 3 kHz can be written to tape for offline processing. For this reason the LHCb data acquisition system -- trigger -- plays a key role in selecting signal events and rejecting background. In contrast to previous experiments at hadron colliders like for example CDF or D0, the bulk of the LHCb trigger is implemented in software and deployed on a farm of 20k parallel processing nodes. This system, called the High Level Trigger (HLT) is responsible for reducing the rate from the maximum at which the detector can be read out, 1.1 MHz, to the 3 kHz which can be processed offline,and has 20 ms in which to process and accept/reject each event. In order to minimize systematic uncertainties, the HLT was designed from the outset to reuse the offline reconstruction and selection code, and is based around multiple independent and redunda...

  3. Comparative Investigation of Shared Filesystems for the LHCb Online Cluster

    International Nuclear Information System (INIS)

    Vijay Kartik, S; Neufeld, Niko

    2012-01-01

    This paper describes the investigative study undertaken to evaluate shared filesystem performance and suitability in the LHCb Online environment. Particular focus is given to the measurements and field tests designed and performed on an in-house OpenAFS setup; related comparisons with NFSv4 and GPFS (a clustered filesystem from IBM) are presented. The motivation for the investigation and the test setup arises from the need to serve common user-space like home directories, experiment software and control areas, and clustered log areas. Since the operational requirements on such user-space are stringent in terms of read-write operations (in frequency and access speed) and unobtrusive data relocation, test results are presented with emphasis on file-level performance, stability and “high-availability” of the shared filesystems. Use cases specific to the experiment operation in LHCb, including the specific handling of shared filesystems served to a cluster of 1500 diskless nodes, are described. Issues of prematurely expiring authenticated sessions are explicitly addressed, keeping in mind long-running analysis jobs on the Online cluster. In addition, quantitative test results are also presented with alternatives including NFSv4. Comparative measurements of filesystem performance benchmarks are presented, which are seen to be used as reference for decisions on potential migration of the current storage solution deployed in the LHCb online cluster.

  4. Measurements of b-baryon properties at LHCb

    CERN Document Server

    Marki, Raphael

    The LHCb experiment located at the Large Hadron Collider at CERN collected its first data from proton-proton collisions between December 2009 and December 2012. Based on data recorded in 2010, several software alignments of the LHCb tracking stations are performed. The procedure includes vertex and mass constraints from the $D^0 \\rightarrow K^+ \\pi^-$ decay. A precision of 15 $\\mu$m is achieved and the alignment constants were used for high-precision measurements at LHCb with 2010 data. In addition the results of the alignments helped to improve the understanding of the procedure. Exploiting the data set recorded during the year 2011, the masses of the weakly-decaying $\\Lambda_b^0, \\Xi_b^-$ and $ \\Omega_b^-$ baryons are measured: \\begin{eqnarray*} M(\\Lambda_b^0) & = & 5619.53 \\pm 0.13 \\rm \\ (stat) \\pm 0.45 \\ (syst) \\ MeV/c^2 , \\\\ M(\\Xi_b^-) & = & 5795.8 \\pm 0.9 \\rm \\ (stat) \\pm 0.4 \\ (syst) \\ MeV/c^2 , \\\\ M(\\Omega_b^-) & = & 6046.0 \\pm 2.2 \\rm \\ (stat) \\pm 0.5 \\ (syst) \\ M...

  5. The LHCb RICH system; detector description and operation

    Energy Technology Data Exchange (ETDEWEB)

    Papanestis, A., E-mail: antonis.papanestis@stfc.ac.uk

    2014-12-01

    Two RICH detectors provide positive charged hadron identification in the LHCb experiment at the Large Hadron Collider at CERN. RICH 1 covers the full acceptance of the spectrometer and contains two radiators: aerogel and C{sub 4}F{sub 10}. RICH 2 covers half the acceptance and uses CF{sub 4} as a Cherenkov radiator. Photon detection is performed by the Hybrid Photon Detectors (HPDs), with silicon pixel sensors and bump-bonded readout encapsulated in a vacuum tube for efficient, low-noise single photon detection. The LHCb RICH detectors form a complex system of three radiators, 120 mirrors and 484 photon detectors operating in the very challenging environment of the LHC. The high performance of the system in pion and kaon identification in the momentum range of 2–100 GeV/c is reached only after careful calibration of many parameters. Operational efficiency above 99% was achieved by a high level of automatization in the operation of the detectors, from switching-on to error recovery. The challenges of calibrating and operating such a system will be presented. - Highlights: • This paper describes the operation and calibration of the LHCb RICH detectors. • The scintillation of CF{sub 4} was successfully suppressed with CO{sub 2}. • The refractive index of the gas radiators was calibrated with data to an accuracy better than 0.1%. • The Hybrid Photons Detectors were calibrated for operation in a magnetic field without loss of resolution.

  6. Detection of {alpha} particles using semiconductors. Application to the control of plutonium extraction; Detection des particules {alpha} par semiconducteurs application au controle de l'extraction du plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Tanguy, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-03-01

    A study is made of a particles produced by thick sources, using either diffused junction or surface barrier semiconductor detectors for controlling continuously the plutonium extraction process. For this, a presenting apparatus is described in which the solutions to be analyzed flow in contact with the detector protected by a thin mica membrane. A method is described which gives a precise recording of the spectra and which thus allows the separation of two or more {alpha} emitters present in the same solution. This method has been applied to the measurement of {sup 239}Pu in the the presence of {sup 241}Am with an accuracy of {+-}5 per cent. In the second part of the report is considered the detection of plutonium in solutions of {beta} - {gamma} emitting fission products. Pile-up is reduced by using a fast amplification chain associated to totally depleted thin detectors. Under these conditions a few mg of {sup 239}Pu can be detected in solutions of fission products having an activity of 100 curies/liter. A method is given for discriminating {alpha} and {beta} particles, it is based on the difference in the collection times for the charges liberated by these particles in the detector. (author) [French] On etudie la detection de particules {alpha} issues de sources epaisses par detecteurs semiconducteurs a jonction diffusee ou a barriere de surface pour le controle continu du procede d'extraction du plutonium. A cet effet on decrit un appareil presentateur dans lequel les solutions a analyser circulent au contact du detecteur protege par une membrane mince de mica. On decrit une methode qui permet par le trace precis des spectres de separer deux ou plusieurs emetteurs {alpha} presents dans une meme solution. Cette methode a ete appliquee a la mesure du {sup 239}Pu en presence de {sup 241}Am avec une precision de {+-} 5 pour cent. Dans la deuxieme partie on traite de la detection du plutonium dans des solutions de produits de fission emetteurs {beta} and {gamma}. On

  7. Observation of $B_{s}^{0} \\to \\mu ^{+} \\mu ^{-}$ at CMS and LHCb and Future Plans at LHCb

    CERN Document Server

    Evans, Hannah

    2016-01-01

    The branching fractions of the decays $B^{0} \\to \\mu^{+} \\mu^{-}$ and $B_{s}^{0} \\to \\mu^{+} \\mu^{-}$ are highly suppressed in the Standard Model but can be modified by contributions from new physics models. The combined result from the CMS and LHCb Run 1 data for the $B^{0} \\to \\mu^{+} \\mu^{-}$ and $B_{s}^{0} \\to \\mu^{+} \\mu^{-}$ branching fractions is presented here. The measured results are $\\mathcal{B}(B_{s}^{0} \\to \\mu^{+} \\mu^{-}) = (2.8^{+0.7}_{-0.6})\\times 10^{-9}$ at $6.2 \\sigma$ statistical significance and $\\mathcal{B}(B^{0} \\to \\mu^{+} \\mu^{-}) = (3.9^{+1.6}_{-1.4})\\times 10^{-10}$ at $3.0 \\sigma$ statistical significance, both results are consistent with Standard Model predictions. A brief discussion of the future prospects for the study of $B^{0} \\to \\mu^{+} \\mu^{-}$ and $B_{s}^{0} \\to \\mu^{+} \\mu^{-}$ at the LHCb is also included.

  8. Jobs masonry in LHCb with elastic Grid Jobs

    Science.gov (United States)

    Stagni, F.; Charpentier, Ph

    2015-12-01

    In any distributed computing infrastructure, a job is normally forbidden to run for an indefinite amount of time. This limitation is implemented using different technologies, the most common one being the CPU time limit implemented by batch queues. It is therefore important to have a good estimate of how much CPU work a job will require: otherwise, it might be killed by the batch system, or by whatever system is controlling the jobs’ execution. In many modern interwares, the jobs are actually executed by pilot jobs, that can use the whole available time in running multiple consecutive jobs. If at some point the available time in a pilot is too short for the execution of any job, it should be released, while it could have been used efficiently by a shorter job. Within LHCbDIRAC, the LHCb extension of the DIRAC interware, we developed a simple way to fully exploit computing capabilities available to a pilot, even for resources with limited time capabilities, by adding elasticity to production MonteCarlo (MC) simulation jobs. With our approach, independently of the time available, LHCbDIRAC will always have the possibility to execute a MC job, whose length will be adapted to the available amount of time: therefore the same job, running on different computing resources with different time limits, will produce different amounts of events. The decision on the number of events to be produced is made just in time at the start of the job, when the capabilities of the resource are known. In order to know how many events a MC job will be instructed to produce, LHCbDIRAC simply requires three values: the CPU-work per event for that type of job, the power of the machine it is running on, and the time left for the job before being killed. Knowing these values, we can estimate the number of events the job will be able to simulate with the available CPU time. This paper will demonstrate that, using this simple but effective solution, LHCb manages to make a more efficient use of

  9. LHCb: Search for the rare decays $B^0_{(s)} \\to \\mu^+\\mu^-$ with the LHCb Experiment

    CERN Multimedia

    Adrover Pacheco, C

    2011-01-01

    A review of the search for the very rare decays $B^{0}_{s} \\rightarrow \\mu^+ \\mu^-$ and $B^{0} \\rightarrow \\mu^+ \\mu^-$ with the LHCb experiment is presented. These decays are suppressed within the Standard Model as they can only occur via helicity suppressed loop diagrams. However, their amplitudes can be significantly different in many New Physics scenarios, especially in those with an extended Higgs sector. Therefore, these decays are a sensitive probe of physics beyond the Standard Model. The study is performed using $\\sim 37$ $pb^{-1}$ of pp collisions at $\\sqrt{s}$ = 7 TeV collected by the experiment at the Large Hadron Collider at CERN. For these dimuon decays the LHCb has reached sensitivities similar to the best existing limits. The resulting upper limits are $\\mathcal{B}(B^{0}_{s} \\rightarrow \\mu^+ \\mu^-)<$ 56 $\\times$ $10^{-9}$ and $\\mathcal{B}(B^{0} \\rightarrow \\mu^+ \\mu^-)<$ 15 $\\times$ $10^{-9}$ at $95\\%$ confidence level. With the number of pp colisions expected in 2011 the LHCb will ...

  10. LHCb: Characterisation and magnetic field properties of Multianode Photomultiplier tubes for the use in LHCb Upgrade RICH detectors

    CERN Multimedia

    Eisenhardt, S; Morris, A; Needham, M; Neill, J

    2013-01-01

    A key feature of the LHCb upgrade, scheduled for 2019, is to remove the first level trigger and its data reduction from 40MHz to 1MHz, which is implemented in the on-detector readout electronics. The consequence for the LHCb Ring Imaging Cherenkov (RICH) detectors is that the Hybrid Photon Detectors need to be replaced as the readout chip is embedded in the tubes. Baseline for replacement are Multianode Photomultiplier tubes (MaPMT) and new readout electronics. Here we report about characterisation studies of the model Hamamatsu R11265 in the effort to qualify them for use in the LHCb RICH upgrade. Comparisons to the known model R7600 are also made. Two types of readout electronics are used. Most measurements to characterise the properties of the MaPMTs are taken with a VME based reference readout, using a x100 linear amplification and the CAEN V792 12-bit charge integrating digitiser. This allows to derive the signal properties from fits to the single photon spectra. In addition a prototype readout using the...

  11. LHCb Results on Semileptonic B/B$_s$/$\\Lambda_b$ Decays

    CERN Document Server

    Bozzi, Concezio

    2013-01-01

    Studies of semileptonic decays of b hadrons with the LHCb experiment are reported. In particular, measurements of the b hadron production fractions at the LHC and Bs semileptonic decays in P-wave charmed mesons are presented. An outlook of the LHCb potential in measuring the CKM matrix elements Vub and Vcb, as well as decays involving taus, is given.

  12. CP violation in charm and other recent charm results from LHCb

    CERN Document Server

    Rademacker, Jonas

    2012-01-01

    The LHCb experiment has accumulated an unprecedented sample of charm data. In these proceedings we present measurements of CP violation and rare in charm in LHCb data accu­ mulated in 2010 and 2011. Many of these measurements are the most precise today.

  13. Determination of the flux per electron-volt at the resonance energy of gold by means op thick gold detectors (1962); Determination des flux par electron-volt a l'energie de resonance de l'or a l'aide de detecteurs d'or epais. (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Brisbois, J; Fogagnolo, G [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1962-07-01

    We calculated the coefficients which allow determining a neutron flux at 5 eV by means of 2/10 mm thick gold detectors on Geiger-Muller counter assemblies. These coefficients were obtained comparing the thick detectors with the thin ones. (authors) [French] Nous avons calcule les coefficients permettant de determiner le flux de neutrons a 5 eV a partir de comptages de detecteurs d'or de 2/10 mm d'epaisseur sur des groupes a compteur de Geiger-Muller. Ces coefficients ont ete obtenus en comparant les detecteurs epais avec des detecteurs minces. (auteurs)

  14. Studies on radiation-image detectors; Etudes sur les detecteurs a images de rayonnements; Izuchenie detektorov izobrazheniya radiatsii; Estudios sobre detectores de radiaciones productores de imagenes

    Energy Technology Data Exchange (ETDEWEB)

    Reiffel, L [Armour Research Foundation, Chicago, IL (United States)

    1962-04-15

    data also germane to scintillation-chamber technology. Possible imaging detectors using thick blocks of material which are capable of significant energy storage and stimulated phosphorescence upon irradiation are discussed briefly along with read-out methods using optical scanning beams to eliminate resolution loss due to finite phosphor thickness. (author) [French] Le memoire decrit les travaux qui ont ete entrepris sur des detecteurs de rayonnements capables de fournir des informations tout a fait exactes sur la distribution spatiale. Il s'agit avant tout de determiner des distributions d'intensites dans un plan, ou eventuellement sur un cylindre. Cette categorie de problemes comprend la diffraction des neutrons, la radiographie des neutrons, ainsi que la radiographie aux rayons X ou {gamma} ou les etudes de diffusion avec ces rayons. L'auteur s'occupe surtout des detecteurs a images de rayonnements, fondes sur la distribution des etincelles et sur la luminescence Ou la phosphorescence stimulee. Le laboratoire de Armour Research a mis au point de tres grands compteurs a etincelles, pesant plus de 100 livres et comportant des zones sensibles de l'ordre de 2000 cm{sup 2}, definies par des assemblages de plans comprenant chacun jusqu'a 400 fils d'anode et de cathode, les anodes et les cathodes etant respectivement disposees en quinconce. Un compteur a courant gazeux contenant de l'air ou un melange d'argon et de methane constitue un systeme sensible aux rayonnements alpha; la detection des neutrons lents se fait avec des plaques en {sup 10}B enrichi. Avec d'autres gaz de remplissage l'appareil est sensible aux protons et aux electrons. La lecture de la distribution d'intensite se fait par enregistrement photographique de la distribution des etincelles. Des diagrammes de taches de Laue ont pu etre enregistres en dix minutes a l'aide du reacteur d'Armour Research fonctionnant a faible puissance; le flux de crete dans le coeur etait de 10{sup 11} n/cm{sup 2} s et le

  15. Etude de la mesure du paramètre alpha dans le cadre de la violation de la symétrie CP à l'aide du canal $B_{d}^{0} \\to \\pi^{+} \\pi^{-}\\pi^{0}$ dans l'expérience LHCb

    CERN Document Server

    Robert, Arnaud

    2005-01-01

    L'analyse temporelle du correlogramme de Dalitz du canal a trois corps Bd en pi+ pi- pi0 conduit a l'extraction de l'un des parametres definissant la violation de la symetrie CP dans le Modele Standard Electrofaible, l'angle alpha, exempte d'ambiguites discretes entre 0 et pi. Elle permet, entre autres, d'acceder independamment aux valeurs des principaux parametres QCD regissant la desintegration. La contrepartie experimentale repose cependant sur une statistique de signal suffisamment pure et importante et une maitrise precise de la phenomenologie associee. Combines a un rapport d'embranchement de l'ordre de 2.10^{-5}, ces deux arguments justifient a eux seuls le caractere non trivial d'une telle analyse dans l'environnement hadronique de l'experience dediee LHCb. A partir de la reponse simulee du detecteur, et en particulier des performances du calorimetre electromagnetique, cette these montre l'interet essentiel de la reconstruction specifique des pions neutres tres energiques et la necessite d'introduire ...

  16. A tracking algorithm for the reconstruction of the daughters of long-lived particles in LHCb

    CERN Document Server

    Dendek, Adam Mateusz

    2018-01-01

    A tracking algorithm for the reconstruction of the daughters of long-lived particles in LHCb 5 Jun 2018, 16:00 1h 30m Library, Centro San Domenico () LHC experiments Posters session Speaker Katharina Mueller (Universitaet Zuerich (CH)) Description The LHCb experiment at CERN operates a high precision and robust tracking system to reach its physics goals, including precise measurements of CP-violation phenomena in the heavy flavour quark sector and searches for New Physics beyond the Standard Model. The track reconstruction procedure is performed by a number of algorithms. One of these, PatLongLivedTracking, is optimised to reconstruct "downstream tracks", which are tracks originating from decays outside the LHCb vertex detector of long-lived particles, such as Ks or Λ0. After an overview of the LHCb tracking system, we provide a detailed description of the LHCb downstream track reconstruction algorithm. Its computational intelligence part is described in details, including the adaptation of the employed...

  17. 100 Gbps PCI-Express readout for the LHCb upgrade

    International Nuclear Information System (INIS)

    Durante, P.; Neufeld, N.; Schwemmer, R.; Balbi, G.; Marconi, U.

    2015-01-01

    We present a new data acquisition system under development for the next upgrade of the LHCb experiment at CERN. We focus in particular on the design of a new generation of readout boards, the PCIe40, and on the viability of PCI-Express as an interconnect technology for high speed readout. We show throughput measurements across the PCI-Express bus, on Altera Stratix 5 devices, using a DMA mechanism and different synchronization schemes between the FPGA and the readout unit. Finally we discuss hardware and software design considerations necessary to achieve a data throughput of 100 Gbps in the final readout board

  18. Framework TDR for the LHCb Upgrade Technical Design Report

    CERN Document Server

    Bediaga, I; Ferreira Rodrigues, F; Magnin, J; Massafferri, A; Nasteva, I; dos Reis, A C; Amato, S; Carvalho Akiba, K; De Paula, L; Francisco, O; Gandelman, M; Gomes, A; Lopes, J H; Otalora Goicochea, J M; Polycarpo, E; Rangel, M S; Souza De Paula, B; Vieira, D; Göbel, C; Molina Rodriguez, J; Chen, P; Gao, Y; Gong, G; Gong, H; Jing, F; Li, L; Li, Y; Liu, B; Lu, H; Shao, B; Wu, S; Xue, T; Yang, Z; Yuan, X; Zeng, M; Zhang, F; Zhang, Y; Zhong, L; De Bonis, I; Decamp, D; Drancourt, C; Ghez, Ph; Hopchev, P; Lees, J -P; Machikhiliyan, I V; Minard, M -N; Pietrzyk, B; T'Jampens, S; Tisserand, V; Tournefier, E; Vouters, G; Ajaltouni, Z; Chanal, H; Cogneras, E; Deschamps, O; El Rifai, I; Henrard, P; Hoballah, M; Jahjah Hussein, M; Lefèvre, R; Li Gioi, L; Monteil, S; Niess, V; Perret, P; Roa Romero, D A; Sobczak, K; Adrover, C; Aslanides, E; Cachemiche, J -P; Cogan, J; Duval, P -Y; Hachon, F; Khanji, B; Le Gac, R; Leroy, O; Mancinelli, G; Maurice, E; Perrin-Terrin, M; Rethore, F; Sapunov, M; Serrano, J; Tsaregorodtsev, A; Barsuk, S; Beigbeder-Beau, C; Cacérès, T; Callot, O; Charlet, D; Duarte, O; He, J; Jean-Marie, B; Kochebina, O; Lefrançois, J; Machefert, F; Martín Sánchez, A; Nicol, M; Robbe, P; Schune, M -H; Teklishyn, M; Tocut, V; Viaud, B; Videau, I; Ben-Haim, E; Benayoun, M; David, P; Del Buono, L; Martens, A; Polci, F; Brambach, T; Cauet, Ch; Deckenhoff, M; Domke, M; Ekelhof, R; Kaballo, M; Karbach, T M; Kruse, F; Merkel, J; Rudloff, K; Schleich, S; Schlupp, M; Spaan, B; Swientek, S; Warda, K; Wishahi, J; Bauer, C; Britsch, M; Föhr, C; Fontana, M; Fuchs, H; Hofmann, W; Kihm, T; Popov, D; Schmelling, M; Volyanskyy, D; Voss, H; Zavertyaev, M; Bachmann, S; Bien, A; Blouw, J; Dordei, F; Färber, C; Gersabeck, E; Hansmann-Menzemer, S; Jaeger, A; Kreplin, K; Krocker, G; Linn, C; Marks, J; Meissner, M; Nikodem, T; Seyfert, P; Stahl, S; van Tilburg, J; Uwer, U; Wandernoth, S; Wiedner, D; Zhelezov, A; Grünberg, O; Hartmann, T; Voß, C; Waldi, R; Bifani, S; Farry, S; Ilten, P; Kechadi, T; Mathe, Z; McNulty, R; Wallace, R; Zhang, W C; Milanes, D A; Palano, A; Carbone, A; D'Antone, I; Derkach, D; Falabella, A; Galli, D; Lax, I; Marconi, U; Perazzini, S; Vagnoni, V; Valenti, G; Zangoli, M; Bonivento, W; Cadeddu, S; Cardini, A; Lai, A; Manca, G; Oldeman, R; Saitta, B; Baldini, W; Bozzi, C; Evangelisti, F; Landi, L; Mazurov, A; Savrie, M; Squerzanti, S; Vecchi, S; Bizzeti, A; Frosini, M; Graziani, G; Passaleva, G; Veltri, M; Anelli, M; Archilli, F; Bencivenni, G; Campana, P; Ciambrone, P; De Simone, P; Felici, G; Lanfranchi, G; Palutan, M; Saputi, A; Sarti, A; Sciascia, B; Soomro, F; Cardinale, R; Fontanelli, F; Patrignani, C; Petrolini, A; Calvi, M; Furcas, S; Giachero, A; Gotti, C; Kucharczyk, M; Maino, M; Matteuzzi, C; Pessina, G; Carboni, G; De Capua, S; Sabatino, G; Santovetti, E; Satta, A; Alves Jr, A A; Auriemma, G; Bocci, V; Martellotti, G; Penso, G; Pinci, D; Santacesaria, R; Satriano, C; Sciubba, A; Nisar, S; Morawski, P; Polok, G; Witek, M; Muryn, B; Oblakowska-Mucha, A; Senderowska, K; Szumlak, T; Guzik, Z; Nawrot, A; Szczekowski, M; Ukleja, A; Burducea, I; Coca, C; Dogaru, M; Grecu, A; Maciuc, F; Muresan, R; Orlandea, M; Pavel-Nicorescu, C; Popovici, B; Stoica, S; Straticiuc, M; Teodorescu, E; Alkhazov, G; Bochin, B; Bondar, N; Dzyuba, A; Gets, S; Golovtsov, V; Kashchuk, A; Maev, O; Matveev, M; Sagidova, N; Shcheglov, Y; Volkov, S; Vorobyev, A; Balagura, V; Belogurov, S; Belyaev, I; Egorychev, V; Golubkov, D; Kvaratskheliya, T; Savrina, D; Semennikov, A; Shatalov, P; Shevchenko, V; Zhokhov, A; Berezhnoy, A; Bogdanova, G; Komarov, I; Korolev, M; Leflat, A; Nikitin, N; Volkov, V; Zverev, E; Filippov, S; Gushchin, E; Karavichev, O; Kravchuk, L; Kudenko, Y; Laptev, S; Tikhonov, A; Bondar, A; Eidelman, S; Krokovny, P; Kudryavtsev, V; Shekhtman, L; Vorobyev, V; Artamonov, A; Belous, K; Dzhelyadin, R; Guz, Yu; Novoselov, A; Obraztsov, V; Ostankov, A; Romanovsky, V; Shapkin, M; Stenyakin, O; Yushchenko, O; Abellan Beteta, C; Calvo Gomez, M; Camboni, A; Casajus Ramo, A; Comerma-Montells, A; Domingo Bonal, F; Garrido, L; Gascon, D; Grabalosa Gándara, M; Graciani Diaz, R; Graugés, E; Lopez Asamar, E; Mauricio, J; Mendez-Munoz, V; Pérez-Calero Yzquierdo, A; Picatoste Olloqui, E; Pie Valls, B; Potterat, C; Puig Navarro, A; Rosello, M; Ruiz, H; Vazquez Gomez, R; Vilasis-Cardona, X; Adeva, B; Alvarez Cartelle, P; Cid Vidal, X; Dosil Suárez, A; Esperante Pereira, D; Fernandez Albor, V; Gallas Torreira, A; Hernando Morata, J A; Pazos Alvarez, A; Perez Trigo, E; Plo Casasus, M; Rodriguez Perez, P; Saborido Silva, J J; Sanmartin Sedes, B; Santamarina Rios, C; Seco, M; Vazquez Regueiro, P; Visniakov, J; Albrecht, J; Alessio, F; Barschel, C; Blake, T; Bonaccorsi, E; Brarda, L; Buytaert, J; Cattaneo, M; Chadaj, B; Charpentier, Ph; Chebbi, M; Ciba, K; Clemencic, M; Closier, J; Collins, P; Corajod, B; Corti, G; Couturier, B; D'Ambrosio, C; Decreuse, G; Dijkstra, H; Dumps, R; Ferro-Luzzi, M; Forty, R; Fournier, C; Frank, M; Frei, C; Gaspar, C; Gersabeck, M; Gligorov, V V; Granado Cardoso, L A; Gys, T; Haen, C; van Herwijnen, E; Jacobsson, R; Jamet, O; Jost, B; Karacson, M; Kristic, R; Lacarrere, D; Lanciotti, E; Langenbruch, C; Lindner, R; Liu, G; Martinez Santos, D; Matev, R; Neufeld, N; Panman, J; Pepe Altarelli, M; Piedigrossi, D; Rauschmayr, N; Roiser, S; Roy, L; Ruf, T; Schindler, H; Schmidt, B; Schneider, T; Schopper, A; Schwemmer, R; Stagni, F; Subbiah, V K; Teubert, F; Thomas, E; Tonelli, D; Ubeda Garcia, M; Ullaland, O; Vesterinen, M; Wicht, J; Witzeling, W; Wyllie, K; Zvyagin, A; Amhis, Y; Bay, A; Bernard, F; Blanc, F; Bressieux, J; Cowan, G A; Degaudenzi, H; Dupertuis, F; Fave, V; Frei, R; Gauvin, N; Haefeli, G; Jaton, P; Keune, A; Knecht, M; La Thi, V N; Lopez-March, N; Luisier, J; Märki, R; Muster, B; Nakada, T; Nguyen, A D; Nguyen-Mau, C; Prisciandaro, J; Rakotomiaramanana, B; Rouvinet, J; Schneider, O; Szczypka, P; Tourneur, S; Tran, M T; Veneziano, G; Anderson, J; Bernet, R; Büchler-Germann, A; Bursche, A; Chiapolini, N; De Cian, M; Elsasser, Ch; 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    2012-01-01

    This document is a Framework Technical Design Report for the upgrade of the LHCb experiment. It adds to the information in the Letter of Intent, in particular concerning the foreseen schedule, cost and participating institutes. Updates are given for the physics performance, based on the experience gained with the first full year of data taking, on the detector requirements and the progress of the sub-system R&D. Within the framework presented here, it is expected that the individual sub-system TDRs will follow on completion of the R&D phase in the next year.

  19. The LHCb vertex locator and level-1 trigger

    CERN Document Server

    Dijkstra, H

    2000-01-01

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

  20. Measurement of the CKM angle $\\gamma$ at LHCb

    CERN Multimedia

    Gersabeck, M

    2009-01-01

    The precise measurement of the CKM unitarity triangle angle $\\gamma$ is a key goal of the LHCb physics programme. The uncertainty on $\\gamma$, the currently least-well known of the three angles, will be reduced dramatically. Complementary measurements will be made in tree-level processes, and modes where loop diagrams play an important role. The tree-level measurements will cover time-integrated as well as time- dependent measurements in both the $B^0_d$ and the $B^0_s$ sectors. The ensemble of these measurements will provide a powerful test of whether new physics phases contribute to heavy-flavour transitions.