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Sample records for lhcb na lhc

  1. 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.

  2. Performance of the LHCb RICH detector at the LHC.

    Science.gov (United States)

    Adinolfi, M; Aglieri Rinella, G; Albrecht, E; Bellunato, T; Benson, S; Blake, T; Blanks, C; Brisbane, S; Brook, N H; Calvi, M; Cameron, B; Cardinale, R; Carson, L; Contu, A; Coombes, M; D'Ambrosio, C; Easo, S; Egede, U; Eisenhardt, S; Fanchini, E; Fitzpatrick, C; Fontanelli, F; Forty, R; Frei, C; Gandini, P; Gao, R; Garra Tico, J; Giachero, A; Gibson, V; Gotti, C; Gregson, S; Gys, T; Haines, S C; Hampson, T; Harnew, N; Hill, D; Hunt, P; John, M; Jones, C R; Johnson, D; Kanaya, N; Katvars, S; Kerzel, U; Kim, Y M; Koblitz, S; Kucharczyk, M; Lambert, D; Main, A; Maino, M; Malde, S; Mangiafave, N; Matteuzzi, C; Mini', G; Mollen, A; Morant, J; Mountain, R; Morris, J V; Muheim, F; Muresan, R; Nardulli, J; Owen, P; Papanestis, A; Patel, M; Patrick, G N; Perego, D L; Pessina, G; Petrolini, A; Piedigrossi, D; Plackett, R; Playfer, S; Powell, A; Rademacker, J H; Ricciardi, S; Rogers, G J; Sail, P; Sannino, M; Savidge, T; Sepp, I; Sigurdsson, S; Soler, F J P; Solomin, A; Soomro, F; Sparkes, A; Spradlin, P; Storaci, B; Thomas, C; Topp-Joergensen, S; Torr, N; Ullaland, O; Vervink, K; Voong, D; Websdale, D; Wilkinson, G; Wotton, S A; Wyllie, K; Xing, F; Young, R

    The LHCb experiment has been taking data at the Large Hadron Collider (LHC) at CERN since the end of 2009. One of its key detector components is the Ring-Imaging Cherenkov (RICH) system. This provides charged particle identification over a wide momentum range, from 2-100 GeV/c. The operation and control, software, and online monitoring of the RICH system are described. The particle identification performance is presented, as measured using data from the LHC. Excellent separation of hadronic particle types (π, K, p) is achieved.

  3. Performance of the LHCb RICH detector at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Adinolfi, M.; Brook, N.H.; Coombes, M.; Hampson, T.; Rademacker, J.H.; Solomin, A.; Voong, D. [University of Bristol, H.H. Wills Physics Laboratory, Bristol (United Kingdom); Aglieri Rinella, G.; Albrecht, E.; D' Ambrosio, C.; Forty, R.; Frei, C.; Gys, T.; Kanaya, N.; Koblitz, S.; Mollen, A.; Morant, J.; Piedigrossi, D.; Storaci, B.; Ullaland, O.; Vervink, K.; Wyllie, K. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Bellunato, T.; Calvi, M.; Fanchini, E.; Giachero, A.; Gotti, C.; Kucharczyk, M.; Maino, M.; Matteuzzi, C.; Perego, D.L.; Pessina, G. [Sezione INFN di Milano Bicocca, Milano (Italy); Benson, S.; Eisenhardt, S.; Fitzpatrick, C.; Kim, Y.M.; Lambert, D.; Main, A.; Muheim, F.; Playfer, S.; Sparkes, A.; Young, R. [University of Edinburgh, School of Physics and Astronomy, Edinburgh (United Kingdom); Blake, T. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Imperial College London, London (United Kingdom); Blanks, C.; Cameron, B.; Carson, L.; Egede, U.; Owen, P.; Patel, M.; Plackett, R.; Savidge, T.; Sepp, I.; Soomro, F.; Websdale, D. [Imperial College London, London (United Kingdom); Brisbane, S.; Contu, A.; Gandini, P.; Gao, R.; Harnew, N.; Hill, D.; Hunt, P.; John, M.; Johnson, D.; Malde, S.; Muresan, R.; Powell, A.; Thomas, C.; Topp-Joergensen, S.; Torr, N.; Wilkinson, G.; Xing, F. [University of Oxford, Department of Physics, Oxford (United Kingdom); Cardinale, R.; Fontanelli, F.; Mini' , G.; Petrolini, A.; Sannino, M. [Sezione INFN di Genova, Genova (Italy); Easo, S. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); STFC Rutherford Appleton Laboratory, Didcot (United Kingdom); Garra Tico, J.; Gibson, V.; Gregson, S.; Haines, S.C.; Jones, C.R.; Katvars, S.; Kerzel, U.; Mangiafave, N.; Rogers, G.J.; Sigurdsson, S.; Wotton, S.A. [University of Cambridge, Cavendish Laboratory, Cambridge (United Kingdom); Mountain, R. [Syracuse University, Syracuse, NY (United States); Morris, J.V.; Nardulli, J.; Papanestis, A.; Patrick, G.N.; Ricciardi, S. [STFC Rutherford Appleton Laboratory, Didcot (United Kingdom); Sail, P.; Soler, F.J.P.; Spradlin, P. [University of Glasgow, School of Physics and Astronomy, Glasgow (United Kingdom); Collaboration: The LHCb RICH Collaboration

    2013-05-15

    The LHCb experiment has been taking data at the Large Hadron Collider (LHC) at CERN since the end of 2009. One of its key detector components is the Ring-Imaging Cherenkov (RICH) system. This provides charged particle identification over a wide momentum range, from 2-100 GeV/c. The operation and control, software, and online monitoring of the RICH system are described. The particle identification performance is presented, as measured using data from the LHC. Excellent separation of hadronic particle types ({pi}, K, p) is achieved. (orig.)

  4. 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...

  5. 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.

  6. LHCb results in proton-nucleus collisions at the LHC

    CERN Document Server

    Mueller, Katharina

    2015-01-01

    The forward acceptance of the LHCb detector allows it to probe proton-ion collisions in a unique kinematic range, complementary to the other LHC experiments. The production of $J/\\Psi$ and $\\Upsilon$-mesons decaying into two muons is studied at the LHCb experiment in proton-lead collisions at a proton-nucleon centre-of-mass energy $\\sqrt sNN = 5 TeV$. The analysis is based on a data sample corresponding to an integrated luminosity of 1.6 nb$^{-1}$. The nuclear modification factor and the forward-backward production ratio are determined for $J/\\Psi$ and $\\Upsilon$(1S) mesons. Clear suppression of prompt $J/\\Psi$ production is observed with respect to the production in proton-proton collisions at large rapidity, while the suppression of $J/\\Psi$ from b-hadron decays is less pronounced. The nuclear modification factor for $\\Upsilon$ (1S) mesons in the forward region is found to be similar to those for $J/\\Psi$ from b-hadron decays. Furthermore, a first observation of Z bosons at large rapidities in proton-lea...

  7. Absolute luminosity measurements with the LHCb detector at the LHC

    CERN Document Server

    Aaij, R; Adinolfi, M; Adrover, C; Affolder, A; Ajaltouni, Z; Albrecht, J; Alessio, F; Alexander, M; Alkhazov, G; Alvarez Cartelle, P; Alves, A A; Amato, S; Amhis, Y; Anderson, J; Appleby, R B; Aquines Gutierrez, O; Archilli, F; Arrabito, L; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Bachmann, S; Back, J J; Bailey, D S; Balagura, V; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Bates, A; Bauer, C; Bauer, Th; Bay, A; Bediaga, I; Belous, K; Belyaev, I; Ben-Haim, E; Benayoun, M; Bencivenni, G; Benson, S; Benton, J; Bernet, R; Bettler, M-O; van Beuzekom, M; Bien, A; Bifani, S; Bizzeti, A; Bjørnstad, P M; Blake, T; Blanc, F; Blanks, C; Blouw, J; Blusk, S; Bobrov, A; Bocci, V; Bondar, A; Bondar, N; Bonivento, W; Borghi, S; Borgia, A; Bowcock, T J V; Bozzi, C; Brambach, T; van den Brand, J; Bressieux, J; Brett, D; Brisbane, S; Britsch, M; Britton, T; Brook, N H; Brown, H; Büchler-Germann, A; Burducea, I; Bursche, A; Buytaert, J; Cadeddu, S; Caicedo Carvajal, J M; Callot, O; Calvi, M; Calvo Gomez, M; Camboni, A; Campana, P; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carson, L; Carvalho Akiba, K; Casse, G; Cattaneo, M; Charles, M; Charpentier, Ph; Chiapolini, N; Ciba, K; Cid Vidal, X; Ciezarek, G; 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; Cook, A; Coombes, M; Corti, G; Cowan, G A; Currie, R; D'Almagne, B; D'Ambrosio, C; David, P; De Bonis, I; De Capua, S; De Cian, M; De Lorenzi, F; De Miranda, J M; De Paula, L; De Simone, P; Decamp, D; Deckenhoff, M; Degaudenzi, H; Deissenroth, M; Del Buono, L; Deplano, C; Deschamps, O; Dettori, F; Dickens, J; Dijkstra, H; Diniz Batista, P; Donleavy, S; Dordei, F; Dosil Suárez, A; Dossett, D; Dovbnya, A; Dupertuis, F; Dzhelyadin, R; Eames, C; Easo, S; Egede, U; Egorychev, V; Eidelman, S; van Eijk, D; Eisele, F; Eisenhardt, S; Ekelhof, R; Eklund, L; Elsasser, Ch; d'Enterria, D G; Esperante Pereira, D; Estève, L; Falabella, A; Fanchini, E; Färber, C; Fardell, G; Farinelli, C; Farry, S; Fave, V; Fernandez Albor, V; Ferro-Luzzi, M; Filippov, S; Fitzpatrick, C; Fontana, M; Fontanelli, F; Forty, R; Frank, M; Frei, C; Frosini, M; Furcas, S; Gallas Torreira, A; Galli, D; Gandelman, M; Gandini, P; Gao, Y; Garnier, J-C; Garofoli, J; Garra Tico, J; Garrido, L; Gaspar, C; Gauvin, N; Gersabeck, M; Gershon, T; Ghez, Ph; Gibson, V; Gligorov, V V; Göbel, C; Golubkov, D; Golutvin, A; Gomes, A; Gordon, H; Grabalosa Gándara, M; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graziani, G; Grecu, A; Gregson, S; Gui, B; Gushchin, E; Guz, Yu; Gys, T; Haefeli, G; Haen, C; Haines, S C; Hampson, T; Hansmann-Menzemer, S; Harji, R; Harnew, N; Harrison, J; Harrison, P F; He, J; Heijne, V; Hennessy, K; Henrard, P; Hernando Morata, J A; van Herwijnen, E; Hicks, E; Hofmann, W; Holubyev, K; Hopchev, P; Hulsbergen, W; Hunt, P; Huse, T; Huston, R S; Hutchcroft, D; Hynds, D; Iakovenko, V; Ilten, P; Imong, J; Jacobsson, R; Jaeger, A; Jahjah Hussein, M; Jans, E; Jansen, F; Jaton, P; Jean-Marie, B; Jing, F; John, M; Johnson, D; Jones, C R; Jost, B; Kandybei, S; Karacson, M; Karbach, T M; Keaveney, J; Kerzel, U; Ketel, T; Keune, A; Khanji, B; Kim, Y M; Knecht, M; Koblitz, S; Koppenburg, P; Kozlinskiy, A; Kravchuk, L; Kreplin, K; Kreps, M; Krocker, G; Krokovny, P; Kruse, F; Kruzelecki, K; Kucharczyk, M; Kukulak, S; Kumar, R; Kvaratskheliya, T; La Thi, V N; Lacarrere, D; Lafferty, G; Lai, A; Lambert, D; Lambert, R W; Lanciotti, E; Lanfranchi, G; Langenbruch, C; Latham, T; Le Gac, R; van Leerdam, J; Lees, J-P; Lefèvre, R; Leflat, A; Lefrançois, J; Leroy, O; Lesiak, T; Li, L; Li Gioi, L; Lieng, M; Liles, M; Lindner, R; Linn, C; Liu, B; Liu, G; Lopes, J H; Lopez Asamar, E; Lopez-March, N; Luisier, J; Machefert, F; Machikhiliyan, I V; Maciuc, F; Maev, O; Magnin, J; Malde, S; Mamunur, R M D; Manca, G; Mancinelli, G; Mangiafave, N; Marconi, U; Märki, R; Marks, J; Martellotti, G; Martens, A; Martin, L; Martín Sánchez, A; Martinez Santos, D; Massafferri, A; Matev, R; Mathe, Z; Matteuzzi, C; Matveev, M; Maurice, E; Maynard, B; Mazurov, A; McGregor, G; McNulty, R; Mclean, C; Meissner, M; Merk, M; Merkel, J; Messi, R; Miglioranzi, S; Milanes, D A; Minard, M-N; Monteil, S; Moran, D; Morawski, P; Mountain, R; Mous, I; Muheim, F; Müller, K; Muresan, R; Muryn, B; Musy, M; Mylroie-Smith, J; Naik, P; Nakada, T; Nandakumar, R; Nardulli, J; Nasteva, I; Nedos, M; Needham, M; Neufeld, N; Nguyen-Mau, C; Nicol, M; Nies, S; Niess, V; Nikitin, N; Oblakowska-Mucha, A; Obraztsov, V; Oggero, S; Ogilvy, S; Okhrimenko, O; Oldeman, R; Orlandea, M; Otalora Goicochea, J M; Owen, P; Pal, B; Palacios, J; Palutan, M; Panman, J; Papanestis, A; Pappagallo, M; Parkes, C; Parkinson, C J; Passaleva, G; Patel, G D; Patel, M; Paterson, S K; 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; Petrella, A; Petrolini, A; Pie Valls, B; Pietrzyk, B; Pilar, T; Pinci, D; Plackett, R; Playfer, S; Plo Casasus, M; Polok, G; Poluektov, A; Polycarpo, E; Popov, D; Popovici, B; Potterat, C; Powell, A; du Pree, T; Prisciandaro, J; Pugatch, V; Puig Navarro, A; Qian, W; Rademacker, J H; Rakotomiaramanana, B; Rangel, M S; Raniuk, I; Raven, G; Redford, S; Reid, M M; dos Reis, A C; Ricciardi, S; Rinnert, K; Roa Romero, D A; Robbe, P; Rodrigues, E; Rodrigues, F; Rodriguez Perez, P; Rogers, G J; Roiser, S; Romanovsky, V; Rouvinet, J; Ruf, T; Ruiz, H; Sabatino, G; Saborido Silva, J J; Sagidova, N; Sail, P; Saitta, B; Salzmann, C; Sannino, M; Santacesaria, R; Santamarina Rios, C; 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; 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; Silva Coutinho, R; Skottowe, H P; Skwarnicki, T; Smith, A C; Smith, N A; Sobczak, K; Soler, F J P; Solomin, A; Soomro, F; Souza De Paula, B; Spaan, B; Sparkes, A; Spradlin, P; Stagni, F; Stahl, S; Steinkamp, O; Stoica, S; Stone, S; Storaci, B; Straticiuc, M; Straumann, U; Styles, N; Subbiah, V K; Swientek, S; Szczekowski, M; Szczypka, P; Szumlak, T; T'Jampens, S; Teodorescu, E; Teubert, F; Thomas, C; Thomas, E; van Tilburg, J; Tisserand, V; Tobin, M; Topp-Joergensen, S; Tran, M T; Tsaregorodtsev, A; Tuning, N; Ubeda Garcia, M; Ukleja, A; Urquijo, P; Uwer, U; Vagnoni, V; Valenti, G; Vazquez Gomez, R; Vazquez Regueiro, P; Vecchi, S; Velthuis, J J; Veltri, M; Vervink, K; Viaud, B; Videau, I; Vilasis-Cardona, X; Visniakov, J; Vollhardt, A; Voong, D; Vorobyev, A; Voss, H; Wacker, K; Wandernoth, S; Wang, J; Ward, D R; Webber, A D; Websdale, D; Whitehead, M; Wiedner, D; Wiggers, L; Wilkinson, G; Williams, M P; Williams, M; Wilson, F F; Wishahi, J; Witek, M; Witzeling, W; Wotton, S A; Wyllie, K; Xie, Y; Xing, F; Yang, Z; Young, R; Yushchenko, O; Zavertyaev, M; Zhang, F; Zhang, L; Zhang, W C; Zhang, Y; Zhelezov, A; Zhong, L; Zverev, E; Zvyagin, A

    2012-01-01

    Absolute luminosity measurements are of general interest for colliding-beam experiments at storage rings. These measurements are necessary to determine the absolute cross-sections of reaction processes and are valuable to quantify the performance of the accelerator. LHCb has applied two methods to determine the absolute scale of its luminosity measurements for proton-proton collisions at the LHC with a centre-of-mass energy of 7 TeV. In addition to the classic ``van der Meer scan'' method a novel technique has been developed which makes use of direct imaging of the individual beams using beam-gas and beam-beam interactions. This beam imaging method is made possible by the high resolution of the LHCb vertex detector and the close proximity of the detector to the beams, and allows beam parameters such as positions, angles and widths to be determined. The results of the two methods have comparable precision and are in good agreement. Combining the two methods, an overall precision of 3.5\\% in the absolute lumi...

  8. A brief review of measurements of electroweak bosons at the LHCb experiment in LHC Run 1

    CERN Document Server

    INSPIRE-00340962

    2016-09-15

    The LHCb experiment is one of four major experiments at the LHC. Despite being designed for the study of beauty and charm particles, it has made important contributions in other areas, such as the production and decay of $W$ and $Z$ bosons. Such measurements can be used to study and constrain parton distribution functions, as well as to test perturbative quantum chromodynamics in hard scattering processes. The angular structure of $Z$ boson decays to leptons can also be studied and used to measure the weak mixing angle. The phase space probed by LHCb is particularly sensitive to this quantity, and the LHCb measurement using the dimuon final state is currently the most precise determination of $\\sin^2\\theta^\\text{lept.}_\\text{eff.}$ at the LHC. LHCb measurements made using data collected during the first period of LHC operations (LHC Run 1) are discussed in this review. The article also considers the potential impact of related future measurements.

  9. 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 ...

  10. 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.

  11. LHCb

    CERN Multimedia

    Frank, M; Neufeld, N; Ruf, T; Batista lopes, J C; Perazzini, S; Stagni, F; Dorigo, M; Di canto, A; Battista, V; Birnkraut, A; Uwer, U; Zhelezov, A; Han, X; Kolpin, M; Esen, S; 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; Laptev, V; Krokovnyi, P; Gibson, V; Ward, D R; Doherty, F; Longstaff, I R; Dean, C T; Traill, M T; Bobulska, D; Fiorini, M; Manzali, M; Campana, P; Saputi, A; Ciambrone, P; Morello, M J; Carboni, G; Van veghel, M; Raven, G H; Witek, M; Ossowska, A; Fiutowski, T A; Leflat, A; Kudryashov, I; Dzhelyadin, R; Stenyakin, O; Popov, A; Wang, J; Artuso, M; Rudolph, M S; Batsukh, B; Garrido beltran, L; Rosello canal, M D M; Luengo alvarez, S; Picatoste olloqui, E; Marin benito, C; Sanchez gonzalo, D; Seco miguelez, M A; Vazquez regueiro, P; Lemos cid, E; Fernandez prieto, A; Wilson, F F; Nandakumar, R; Wark, H M; Hecker, M; Baker, S K; Kochenda, L; Shcheglov, Y; Parker, W C; Saitta, B; Brundu, D; Calvi, M; Pessina, G E; Shao, B; Zeng, M; Sun, J; Kechadi, M T; Zheng, Y; Lyu, X; Polukhina, N; Wicht, J G; Rodrigues cavalcante, A B; Buytaert, J; Camilleri, L L; Lindner, R; Corti, G; Ponce, S; Coco, V; Schwemmer, R A; Ravonel salzgeber, M; Aaij, R; Popov, D; Gruber, L; Seyfert, P; Stahl, S; De aguiar francisco, O A; Chrzaszcz, M J; Voneki, B; Masson, G A; Marino, P; Vollhardt, A; Zhukov, V; Niet, R; Haas, T; Leroy, O; Mancinelli, G; Hachon, F; Lisovskyi, V; Naik, P P; Richards, S E; John, M; Nandi, A K; Palano, A; Iarocci, E; Auriemma, G; Shapoval, I; Philippov, S; Petrov, A; Berdiouguine, A; Weisser, C N; Graziani, G; Anderlini, L; 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; Basiladze, S; Volkov, V; Kozachuk, A; Sokoloff, M D; Pappenheimer, C A; Da silva, C L; Blusk, S R; Ely, S E; Wilkinson, M; Merli, A; Marangotto, D; Santana rangel, M; Camboni, A; Orellana martin, D; Gallas torreira, A A; Fernandez albor, V M; Borsato, M; Niess, V; Franek, B; Loveridge, P; Hutchcroft, D E; Shears, T G; Smith, A N; Whitley, M D A; Sutcliffe, W L; Sagidova, N; Vznuzdaev, M; Fontana, M; Mazza, R; Cheng, J; Huang, Y; Hushchyn, M; Hess, M; Crocombe, A C; Needham, M D; Jacobsson, R; Mathe, Z; Rauschmayr, N; Pearce, A; Byczynski, W; Frei, R; Nakada, T; Nguyen mau, C; Pinard, A; Bernet, R; Serra, N; Bezshyiko, I; Wang, Y; Kirn, T; Kruse, F; Bauer, C; Dembinski, H P; De cian, M; Braun, S A; Piucci, A; Kecke, M; Minard, M; Aslanides, E; Barrand, G C; Charlet, D; 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; Petrarca, S; Williams, J M; Boettcher, T J; Tolk, S; Smith, J W; Spradlin, P M; Calabrese, R; Lenisa, P; Neri, I; Bencivenni, G; Lanfranchi, G; Simi, G; Michielin, E; Ceelie, L; Van petten, O R; Pellegrino, A; Roeland, E; Dendek, A M; Nikitin, N; Obraztsov, V; Stone, S L; Olejnik, L; Petruzzo, M; Mendes gandelman, M; Hicheur, A; Silva de oliveira, L G; Adeva andany, B; Hernando morata, J A; Golutvin, A; Humair, T; Gao, Y; Liu, X; Zhu, X; Milanes carreno, D A; Rodriguez lopez, J A; Monroy canon, I A; Borisyak, M; Szymanski, M P; Meinert, N; Qian, W; 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; Straumann, U D; Storaci, B; Mueller, K; Buonaura, A; Spaan, B; Albrecht, J; Ekelhof, R J; Shires, A; Schlupp, M; Demmer, M; Gavardi, L; Muller, J; Schmelzer, T; Lindemann, T; Bachmann, S; Neuner, M; Cachemiche, J; Tou, D Y; Pomery, G J; De capua, S; Burr, C M; Topp-joergensen, S; Bjorn, M; Patrignani, C; Vagnoni, V M; Franchini, P; Kandybei, S; Shekhtman, L; Jones, C R; Cliff, H V; Tully, A M; Soler jermyn, P F; Beddow, J; Luppi, E; Vecchi, S; Corvo, M; De simone, P; Rotondo, M; Satta, A; Merk, M; Jansen, L; Jans, E; Krzemien, W J; Merkin, M; Vasilyev, A; Durham, J M; 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; Stefkova, S; Spiridenkov, E; Makarenkov, G; Filimonov, A; Stepanova, M; Jawahery, A; Petrolini, A; Gong, G; Ruiz vidal, J; Khairullin, E; 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

    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...

  12. The LHCb RICH silica aerogel performance with LHC data

    CERN Multimedia

    Perego, D L

    2010-01-01

    In the LHCb detector at the Large Hadron Collider, powerful charged particle identification is performed by Ring Imaging Cherenkov (RICH) technology. In order to cover the full geometric acceptance and the wide momentum range (1-100 GeV/c), two detectors with three Cherenkov radiators have been designed and installed. In the medium (10-40 GeV/c) and high (30-100 GeV/c) momentum range, gas radiators are used (C4F10 and CF4 respectively). In the low momentum range (1 to a few GeV/c) pion/kaon/proton separation will be done with photons produced in solid silica aerogel. A set of 16 tiles, with the large transverse dimensions ever (20x20 cm$^2$) and nominal refractive index 1.03 have been produced. The tiles have excellent optical properties and homogeneity of refractive index within the tile of ~1%. The first data collected at LHC are used to understand the behaviour of the RICH: preliminary results will be presented and discussed on the performance of silica aerogel and of the gas radiators C4F10 and CF4.

  13. LHCb Physics Motivations for the 2016 Heavy-ion LHC run

    CERN Document Server

    Graziani, Giacomo; Robbe, Patrick; Schmelling, Michael; Schmidt, Burkhard

    2016-01-01

    This document summarizes the arguments to support the request by the LHCb experiment to record an integrated luminosity of 20nb$^-1$ of $p$Pb and Pb$p$ collisions during the LHC heavy ion run of 2016 at a centre-of-mass energy of $\\sqrt{s_{\\rm NN}}=8$ TeV.

  14. An LHCb general-purpose acquisition board for beam and background monitoring at the LHC

    CERN Document Server

    Alessio, F; Guzik, Z

    2011-01-01

    In this paper we will present an LHCb custom-made acquisition board which was developed for a continuous beam and background monitoring during LHC operations at CERN. The paper describes both the conceptual design and its performance, and concludes with results from the first period of beam operations at the LHC. The main purpose of the acquisition board is to process signals from a pair of beam pickups to continuously monitor the intensity of each bunch, and to monitor the phase of the arrival time of each proton bunch with respect to the LHC bunch clock. The extreme versatility of the board also allowed the LHCb experiment to build a high-speed and high-sensitivity readout system for a fast background monitor based on a pair of plastic scintillators. The board has demonstrated very good performance and proved to be conceptually valid during the first months of operations at the LHC. Connected to the beam pickups, it provides the LHCb experiment with a real-time measurement of the total intensity of each bea...

  15. Performance of the LHCb RICH detectors during the LHC Run II

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00261218; D'Ambrosio, Carmelo

    2017-01-01

    The LHCb RICH system provides hadron identification over a wide momentum range $(2–100 ~\\text{GeV}/c)$. This detector system is key to LHCb’s precision flavour physics programme, which has unique sensitivity to physics beyond the standard model. This paper reports on the performance of the LHCb RICH in Run II, following significant changes in the detector and operating conditions. The changes include the refurbishment of significant number of photon detectors, assembled using new vacuum technologies, and the removal of the aerogel radiator. The start of Run II of the LHC saw the beam energy increase to $6.5 ~\\text{TeV}$ per beam and a new trigger strategy for LHCb with full online detector calibration. The RICH information has also been made available for all trigger streams in the High Level Trigger for the first time.

  16. Radiation loads of the detectors for the central region of the LHCb experiment at LHC

    CERN Document Server

    Talanov, V V

    2002-01-01

    The formation of the secondary-radiation field in the central region of the future LHCb experiment at LHC (CERN) was numerically simulated. The specific features of the field characteristics were revealed for different configurations of detectors in the experiment. The radiation loads governing the detector operation in a given radiation environment were evaluated. Methods for optimizing the design of the detectors and the accelerator vacuum chamber were proposed. (15 refs).

  17. Calibration of photomultipliers and initial adjustment of the LHCb Electromagnetic Calorimeter for pilot LHC runs

    CERN Document Server

    Machikhiliyan, Irina

    2013-01-01

    The procedure for the initial adjustment of the LHCb ECAL energy scale is described. The calibration technique to determine the gains of photomultipliers in situ is discussed in details, including its technical implementation and the studies on possible systematic effects. Finally, the di-photon invariant mass distributions from early data collected in the end of 2009 in the course of the LHC start-up are presented, proving the sufficient level of the initial cell-to-cell intercalibration to detect clear signal from $\\pi^0 \\to \\gamma \\gamma$ decays.

  18. Heavy Quarkonia sector in PYTHIA 6.324 tuning, validation and perspectives at LHC(b)

    CERN Document Server

    Bargiotti, M

    2007-01-01

    In this note we investigate the impact of the recent insertion of Color Octet Model processes in PYTHIA version 6.324, through a tuning of different PYTHIA parameters, including the low-p$_T$ behaviour. The Non-relativistic QCD parameters have been chosen according to the most recent theoretical calculations and fits to CDF data. This analysis has been mainly focused on J/$\\psi$ and $\\Upsilon$ prompt production, with a comparison of the Monte Carlo predictions with available data from CDF at Run I and Run II energies. A prediction at the LHC energy, within different acceptance regions (CMS-Atlas and LHCb ones), is also given.

  19. LHCb Vertex Locator: Performance and radiation damage in LHC Run 1 and preparation for Run 2

    Science.gov (United States)

    Szumlak, T.; Obła˛kowska-Mucha, A.

    2016-07-01

    LHCb is a dedicated experiment to study New Physics in the decays of heavy hadrons at the Large Hadron Collider (LHC) at CERN. Heavy hadrons are identified through their flight distance in the Vertex Locator (VELO). The VELO comprises 42 modules made of two n+-on-n 300 μm thick half-disc silicon sensors with R- and Φ-measuring micro-strips. In order to allow retracting the detector, the VELO is installed as two movable halves containing 21 modules each. The detectors are operated in a secondary vacuum and are cooled by a bi-phase CO2 cooling system. During data taking in LHC Run 1 the LHCb VELO has operated with an extremely high efficiency and excellent performance. The track finding efficiency is typically greater than 98%. An impact parameter resolution of less than 35 μm is achieved for particles with transverse momentum greater than 1 GeV/c. An overview of all important performance parameters will be given. The VELO sensors have received a large and non-uniform radiation dose of up to 1.2 ×1014 1 MeV neutron equivalent cm-2 during the first LHC run. Silicon type-inversion has been observed in regions close to the interaction point. The preparations for LHC Run 2 are well under way and the VELO has already recorded tracks from injection line tests. The current status and plans for new operational procedures addressing the non-uniform radiation damage are shortly discussed.

  20. Experiment protection at the LHC and damage limits in LHC(b) silicon detectors

    CERN Document Server

    Ferro-Luzzi, M

    2009-01-01

    The Large Hadron Collider (LHC), once in operation, will represent approximately a 200-fold increase in stored beam energy with respect to previous high energy colliders. Safe operation will critically rely on machine and experiment protection systems. A review is given of possible beam failure modes at the LHC and of the strategy adopted in the LHC experiments to protect the detectors against such events. Damage limits for the detectors are discussed.

  1. Improved performance of the LHCb Outer Tracker in LHC Run 2 arXiv

    CERN Document Server

    d'Argent, Ph.; Grillo, L.; de Vries, J.A.; Ukleja, A.; Aaij, R.; Archilli, F.; Bachmann, S.; Berninghoff, D.; Birnkraut, A.; Blouw, J.; de Cian, M.; Ciezarek, G.; Färber, Ch.; Demmer, M.; Dettori, F.; Gersabeck, E.; Grabowski, J.; Hulsbergen, W.D.; Khanji, B.; Kolpin, M.; Kucharczyk, M.; Malecki, B.P.; Merk, M.; Mulder, M.; Müller, J.; Mueller, V.; Pellegrino, A.; Pikies, M.; Rachwal, B.; Schmelzer, T.; Spaan, B.; Szczekowski, M.; van Tilburg, J.; Tolk, S.; Tuning, N.; Uwer, U.; Wishahi, J.; Witek, M.

    The LHCb Outer Tracker is a gaseous detector covering an area of $5\\times 6 m^2$ with 12 double layers of straw tubes. The performance of the detector is presented based on data of the LHC Run 2 running period from 2015 and 2016. Occupancies and operational experience for data collected in $p p$, pPb and PbPb collisions are described. An updated study of the ageing effects is presented showing no signs of gain deterioration or other radiation damage effects. In addition several improvements with respect to LHC Run 1 data taking are introduced. A novel real-time calibration of the time-alignment of the detector and the alignment of the single monolayers composing detector modules are presented, improving the drift-time and position resolution of the detector by 20\\%. Finally, a potential use of the improved resolution for the timing of charged tracks is described, showing the possibility to identify low-momentum hadrons with their time-of-flight.

  2. LHCb brochure (English version)

    CERN Multimedia

    Lefevre, C

    2009-01-01

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

  3. Power Load from Collision Debris on the LHC Point 8 Insertion Magnets implied by the LHCB Luminosity Increase

    CERN Document Server

    Esposito, L S; Lechner, A; Mereghetti, A; Vlachoudis, V; Patapenka, A

    2013-01-01

    LHCb is aiming to upgrade its goal peak luminosity up to a value of 2 × 1033 cm−2 s−1 after LS2. We investigate the collision debris impact on the machine elements by extensive FLUKA simulations, showing that the present machine layout is substantially compatible with such a luminosity goal. In particular the installation of a TAS (Target Absorber of Secondaries, installed in front of the final focus Q1-Q3 quadrupole triplet in the LHC high luminosity insertions) turns out not to be necessary on the basis of the expected peak power deposition in the Q1 superconducting coils. A warm protection may be desirable to further reduce heat load and dose on the D2 recombination dipole, due to the absence of the TAN (Target Absorber of Neutrals, present in Point 1 and 5).

  4. 24 May 2013 - Rector of the Polish Stanislaw Staszic AGH University of Science and Technology T. Slomka in the LHC tunnel at Point 8 with Senior Polish Staff Member A. Siemko, in LHCb experimental cavern with LHCb Collaboration Spokesperson P. Campana and signing the guest book with Director-General R. Heuer. Adviser for Eastern Europe T. Kurtyka present.

    CERN Multimedia

    Jean-Claude Gadmer

    2013-01-01

    24 May 2013 - Rector of the Polish Stanislaw Staszic AGH University of Science and Technology T. Slomka in the LHC tunnel at Point 8 with Senior Polish Staff Member A. Siemko, in LHCb experimental cavern with LHCb Collaboration Spokesperson P. Campana and signing the guest book with Director-General R. Heuer. Adviser for Eastern Europe T. Kurtyka present.

  5. LHCb Brochure (english version)

    CERN Multimedia

    2004-01-01

    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.

  6. 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.

  7. 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.

  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 (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.

  10. LHCb brochure (Polish 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. LHCb brochure (Catalan version)

    CERN Document Server

    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.

  12. LHCb Detector Performance

    CERN Document Server

    AUTHOR|(CDS)2075808; Adeva, Bernardo; 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, Vladimir; 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

    2015-01-01

    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 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.

  13. Expression of Interest for a Phase-II LHCb Upgrade: Opportunities in flavour physics, and beyond, in the HL-LHC era

    CERN Document Server

    Aaij, Roel; Adinolfi, Marco; 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; Andreassi, Guido; Andreotti, Mirco; Andrews, Jason; Anelli, Mario; Appleby, Robert; Archilli, Flavio; d'Argent, Philippe; Arnau Romeu, Joan; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Babuschkin, Igor; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baker, Sophie; Balagura, Vladislav; Baldini, Wander; Balla, Alessandro; Baranov, Alexander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Baryshnikov, Fedor; Baszczyk, Mateusz; Batozskaya, Varvara; Batsukh, Baasansuren; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Beiter, Andrew; Bel, Lennaert; Bellee, Violaine; Belloli, Nicoletta; Belous, Konstantin; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Beranek, Sarah; Berezhnoy, Alexander; Bernet, Roland; Bertolin, Alessandro; Betancourt, Christopher; Betti, Federico; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bezshyiko, Iaroslava; Bifani, Simone; Billoir, Pierre; Birnkraut, Alex; Bitadze, Alexander; Bizzeti, Andrea; Blake, Thomas; Blanc, Frederic; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Boettcher, Thomas; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Bordyuzhin, Igor; Borgheresi, Alessio; Borghi, Silvia; Borisyak, Maxim; Borsato, Martino; Bossu, Francesco; Boubdir, Meriem; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Braun, Svende; Britton, Thomas; Brodzicka, Jolanta; Brundu, Davide; Buchanan, Emma; Burr, Christopher; Bursche, Albert; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Camboni, Alessandro; Campana, Pierluigi; Campora Perez, Daniel Hugo; Capriotti, Lorenzo; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carletti, Maurizio; Carniti, Paolo; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Casu, Luigi; Cattaneo, Marco; Cavallero, Giovanni; Cenci, Riccardo; Chamont, David; Charles, Matthew; Charpentier, Philippe; Chatzikonstantinidis, Georgios; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu-Faye; Chobanova, Veronika; Chrzaszcz, Marcin; Chubykin, Alexsei; Ciambrone, Paolo; Cid Vidal, Xabier; Ciezarek, Gregory; Citterio, Mauro; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coco, Victor; Coelli, Simone; Cogan, Julien; Cogneras, Eric; Cogoni, Violetta; Cojocariu, Lucian; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombs, George; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Costa Sobral, Cayo Mar; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Crocombe, Andrew; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Da Cunha Marinho, Franciole; 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 Serio, Marilisa; De Simone, Patrizia; Dean, Cameron Thomas; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Demmer, Moritz; Dendek, Adam; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Dey, Biplab; Di Canto, Angelo; Di Nezza, Pasquale; Dijkstra, Hans; Dordei, Francesca; Dorigo, Mirco; Dosil Su{á}rez, Alvaro; Dovbnya, Anatoliy; Dreimanis, Karlis; Dufour, Laurent; Dujany, Giulio; Dungs, Kevin; Durante, Paolo; Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; D{é}l{é}age, Nicolas; Easo, Sajan; Ebert, Marcus; Egede, Ulrik; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Farley, Nathanael; Farry, Stephen; Fay, Robert; Fazzini, Davide; Felici, Giulietto; Ferguson, Dianne; Fernandez, Gerard; Fernandez Prieto, Antonio; Ferrari, Fabio; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fini, Rosa Anna; Fiore, Marco; Fiorini, Massimiliano; Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fleuret, Frederic; Fohl, Klaus; Fontana, Marianna; Fontanelli, Flavio; Forshaw, Dean Charles; Forty, Roger; Franco Lima, Vinicius; Frank, Markus; Frei, Christoph; Fresch, Paolo; Fu, Jinlin; Funk, Wolfgang; Furfaro, Emiliano; F{ä}rber, Christian; Gallas Torreira, Abraham

    2017-01-01

    A Phase-II Upgrade is proposed for the LHCb experiment in order to take full advantage of the flavour-physics opportunities at the HL-LHC, and other topics that can be studied with a forward spectrometer. This Upgrade, which will be installed in Long Shutdown 4 of the LHC (2030), will build on the strengths of the current experiment and the Phase-I Upgrade, but will consist of re-designed sub-systems that can operate at a luminosity of $2 \\times 10^{34}\\,{\\rm cm}^{-2} s^{-1}$, ten times that of the Phase-I Upgrade detector. New and improved detector components will increase the intrinsic performance of the experiment in certain key areas. In particular the installation of a tungsten sampling electromagnetic calorimeter will widen LHCb's capabilities for decays involving $\\pi^0$ and $\\eta$ mesons, electrons, and photons from loop-level penguin processes. The physics motivation is presented, and the prospects for operating the LHCb Interaction Point at high luminosity are assessed. The challenges for the detect...

  14. Expression of Interest for a Phase-II LHCb Upgrade Opportunities in flavour physics, and beyond, in the HL-LHC era

    CERN Document Server

    LHCb, Collaboration

    2017-01-01

    A Phase-II Upgrade is proposed for the LHCb experiment in order to take full advantage of the flavour-physics opportunities at the HL-LHC, and other topics that can be studied with a forward spectrometer. This Upgrade, which would be installed in Long Shutdown 4 of the LHC (2030), will build on the strengths of the current experiment and the Phase-I Upgrade, but will consist of re-designed sub-systems that can operate at a luminosity of 2×10$^{34}$cm$^{-2}s{^-1}$, ten times that of the Phase-I Upgrade detector. New and improved detector components will increase the intrinsic performance of the experiment in certain key areas. In particular the installation of a tungsten sampling electromagnetic calorimeter will widen LHCb's capabilities for decays involving $\\pi{^0}$ and η mesons, and photons from loop-level penguin processes. The physics motivation is presented, and the prospects for operating the LHCb Interaction Point at high luminosity are assessed. The challenges for the detector are described and poss...

  15. 6 March 2013 - Committee for Employment and Learning, Northern Ireland Legislative Assembly, United Kingdom of Great Britain and Northern Ireland in the LHC tunnel and visiting the LHCb experiment at LHC Point 8. Director for Accelerators and Technology S. Myers with Vice-Chair T. Buchanan.

    CERN Multimedia

    Anna Pantelia

    2013-01-01

    6 March 2013 - Committee for Employment and Learning, Northern Ireland Legislative Assembly, United Kingdom of Great Britain and Northern Ireland in the LHC tunnel and visiting the LHCb experiment at LHC Point 8. Director for Accelerators and Technology S. Myers with Vice-Chair T. Buchanan.

  16. 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...

  17. Study on the performance of the Particle Identification Detectors at LHCb after the LHC First Long Shutdown (LS1)

    CERN Document Server

    Fontana, Marianna

    2016-01-01

    During the First Long Shutdown (LS1), the LHCb experiment has introduced major modification in the data-processing procedure and modified part of the detector to deal with the increased energy and the increased heavy-hadron production cross-section. In this contribution we review the performance of the particle identification detectors at LHCb, Rich, Calorimeters, and Muon system, after the LS1

  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. 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.

  20. 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.

  1. 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...

  2. 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.

  3. LHCb experience with LFC replication

    CERN Document Server

    Carbone, Angelo; Dafonte Perez, Eva; D'Apice, Antimo; dell'Agnello, Luca; Duellmann, Dirk; Girone, Maria; Lo Re, Giuseppe; Martelli, Barbara; Peco, Gianluca; Ricci, Pier Paolo; Sapunenko, Vladimir; Vagnoni, Vincenzo; Vitlacil, Dejan

    2007-01-01

    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. 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 Informations (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.

  4. 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...

  5. 28 August 2013 - Ambassador Extraordinary and Plenipotentiary Permanent Representative of Ireland to the United Nations Office and specialized institutions in Geneva Mr G. Corr signing the guest book with CERN Director-General R. Heuer; visiting the LHCb experimental area with LHCb Collaboration Spokesperson P. Campana and visiting the LHC tunnel at Point 8 with International Relations Adviser for Ireland E. Tsesmelis. Accompanied throughout by R. McNulty.

    CERN Multimedia

    Jean-Claude Gadmer

    2013-01-01

    28 August 2013 - Ambassador Extraordinary and Plenipotentiary Permanent Representative of Ireland to the United Nations Office and specialized institutions in Geneva Mr G. Corr signing the guest book with CERN Director-General R. Heuer; visiting the LHCb experimental area with LHCb Collaboration Spokesperson P. Campana and visiting the LHC tunnel at Point 8 with International Relations Adviser for Ireland E. Tsesmelis. Accompanied throughout by R. McNulty.

  6. 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.

  7. Precision luminosity measurements at LHCb

    NARCIS (Netherlands)

    Aaij, R.; Adeva, B.; Adinolfi, 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.; Belous, K.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; Benton, J.; Berezhnoy, A.; Bernet, R.; Bettler, M. -O.; van Beuzekom, M.; Bien, A.; Bifani, S.; Bird, T.; Bizzeti, A.; Bjornstad, P. M.; Blake, T.; Blanc, F.; Blouw, J.; Blusk, S.; Bocci, V.; Bondar, A.; Bondar, N.; Bonivento, W.; Borghi, S.; Borgia, A.; Borsato, M.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Brambach, T.; Bressieux, J.; Brett, D.; Britsch, M.; Britton, T.; Brodzicka, J.; Brook, N. H.; Brown, H.; Bursche, A.; Buytaert, J.; Cadeddu, S.; Calabrese, R.; Calvi, M.; Calvo Gomez, M.; Campana, P.; Perez, D. Campora; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carson, L.; Carvalho Akiba, K.; Casse, G.; Cassina, L.; Garcia, L. Castillo; Cattaneo, M.; Cauet, Ch.; Cenci, R.; Charles, M.; Charpentier, Ph.; Chefdeville, M.; Chen, S.; Cheung, S. -F.; Chiapolini, N.; Chrzaszcz, M.; Ciba, K.; Vidal, X. Cid; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coco, V.; Cogan, J.; Cogneras, E.; Cojocariu, L.; Collazuol, G.; Collins, P.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coombes, M.; Coquereau, S.; Corti, G.; Corvo, M.; Counts, I.; Couturier, B.; Cowan, G. A.; Craik, D. C.; Cruz Torres, M.; Cunliffe, S.; Currie, R.; D'Ambrosio, C.; Dalseno, J.; David, P.; David, P. N. Y.; Davis, A.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Silva, W.; De Simone, P.; Dean, C. -T.; Decamp, D.; Deckenhoff, M.; Del Buono, L.; Deleage, N.; Derkach, D.; Deschamps, O.; Dettori, F.; Di Canto, A.; Dijkstra, H.; Donleavy, S.; Dordei, F.; Dorigo, M.; Dosil Suarez, A.; Dossett, D.; Dovbnya, A.; Dreimanis, K.; Dujany, G.; Dupertuis, F.; Durante, P.; Dzhelyadin, R.; Dziurda, A.; Dzyuba, A.; Easo, S.; Egede, U.; Egorychev, V.; Eidelman, S.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; El Rifai, I.; Elsasser, Ch.; Ely, S.; Esen, S.; Evans, H. -M.; Evans, T.; Falabella, A.; Faerber, C.; Farinelli, C.; Farley, N.; Farry, S.; Fay, R. F.; Ferguson, D.; Fernandez Albor, V.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fiore, M.; Fiorini, M.; Firlej, M.; Fitzpatrick, C.; Fiutowski, T.; Fol, P.; Fontana, M.; Fontanelli, F.; Forty, R.; Francisco, O.; Frank, M.; Frei, C.; Frosini, M.; Fu, J.; Furfaro, E.; Gallas Torreira, A.; Galli, D.; Gallorini, S.; Gambetta, S.; Gandelman, M.; Gandini, P.; Gao, Y.; Garcia Pardinas, J.; Garofoli, J.; Tico, J. Garra; Garrido, L.; Gascon, D.; Gaspar, C.; Gauld, R.; Gavardi, L.; Geraci, A.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Gianelle, A.; Giani, S.; Gibson, V.; Giubega, L.; Gligorov, V. V.; Goebel, C.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gotti, C.; Gandara, M. Grabalosa; Graciani Diaz, R.; Cardoso, L. A. Granado; Grauges, E.; Graziani, G.; Grecu, A.; Greening, E.; Gregson, S.; Griffith, P.; Grillo, L.; Gruenberg, O.; Gui, B.; Gushchin, E.; Guz, Yu.; Gys, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hall, S.; Hamilton, B.; Hampson, T.; Han, X.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; He, J.; Head, T.; Heijne, V.; Hennessy, K.; Henrard, P.; Henry, L.; Hernando Morata, J. A.; van Herwijnen, E.; Hess, M.; Hicheur, A.; Hill, D.; Hoballah, M.; Hombach, C.; Hulsbergen, W.; Hunt, P.; Hussain, N.; Hutchcroft, D.; Hynds, D.; Idzik, M.; Ilten, P.; Jacobsson, R.; Jaeger, A.; Jalocha, J.; Jans, E.; Jaton, P.; Jawahery, A.; Jing, F.; John, M.; Johnson, D.; Jones, C. R.; Joram, C.; Jost, B.; Jurik, N.; Kandybei, S.; Kanso, W.; Karacson, M.; Karbach, T. M.; Karodia, S.; Kelsey, M.; Kenyon, I. R.; Ketel, T.; Khanji, B.; Khurewathanakul, C.; Klaver, S.; Klimaszewski, K.; Kochebina, O.; Kolpin, M.; Komarov, I.; Koopman, R. F.; Koppenburg, P.; Korolev, M.; Kozlinskiy, A.; Kravchuk, L.; Kreplin, K.; Kreps, M.; Krocker, G.; Krokovny, P.; Kruse, F.; Kucewicz, W.; Kucharczyk, M.; Kudryavtsev, V.; Kurek, K.; Kvaratskheliya, T.; La Thi, V. N.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lambert, D.; Lambert, R. W.; Lanfranchi, G.; Langenbruch, C.; Langhans, B.; Latham, T.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Lees, J. -P.; Lefevre, R.; Leflat, A.; Lefrancois, J.; Leo, S.; Leroy, O.; Lesiak, T.; Leverington, B.; Li, Y.; Likhomanenko, T.; Liles, M.; Lindner, R.; Linn, C.; Lionetto, F.; Liu, B.; Lohn, S.; Longstaff, I.; Lopes, J. H.; Lopez-March, N.; Lowdon, P.; Lu, H.; Lucchesi, D.; Luo, H.; Lupato, A.; Luppi, E.; Lupton, O.; Machefert, F.; Machikhiliyan, I. V.; Maciuc, F.; Maev, O.; Malde, S.; Malinin, A.; Manca, G.; Mancinelli, G.; Mapelli, A.; Maratas, J.; Marchand, J. F.; Marconi, U.; Marin Benito, C.; Marino, P.; Maerki, R.; Marks, J.; Martellotti, G.; Martens, A.; Sanchez, A. Martin; Martinelli, M.; Santos, D. Martinez; Martinez Vidal, F.; Martins Tostes, D.; Massafferri, A.; Matev, R.; Mathe, Z.; Matteuzzi, C.; Maurin, B.; Mazurov, A.; McCann, M.; McCarthy, J.; McNab, A.; McNulty, R.; McSkelly, B.; Meadows, B.; Meier, F.; Meissner, M.; Merk, M.; Milanes, D. A.; Minard, M. -N.; Moggi, N.; Molina Rodriguez, J.; Monteil, S.; Morandin, M.; Morawski, P.; Morda, A.; Morello, M. J.; Moron, J.; Morris, A. -B.; Mountain, R.; Muheim, F.; Mueller, K.; Mussini, M.; Muster, B.; Naik, P.; Nakada, T.; Nandakumar, R.; Nasteva, I.; Needham, M.; Neri, N.; Neubert, S.; Neufeld, N.; Neuner, M.; Nguyen, A. D.; Nguyen, T. D.; Nguyen-Mau, C.; Nicol, M.; Niess, V.; Niet, R.; Nikitin, N.; Nikodem, T.; Novoselov, A.; O'Hanlon, D. P.; Oblakowska-Mucha, A.; Obraztsov, V.; Oggero, S.; Ogilvy, S.; Okhrimenko, O.; Oldeman, R.; Onderwater, C. J. G.; Orlandea, M.; Otalora Goicochea, J. M.; Owen, P.; Oyanguren, A.; Pal, B. K.; Palano, A.; Palombo, F.; Palutan, M.; Panman, J.; Papanestis, A.; Pappagallo, M.; Pappalardo, L. L.; Parkes, C.; Parkinson, C. J.; Passaleva, G.; Patel, G. D.; Patel, M.; Patrignani, C.; Pearce, A.; Pellegrino, A.; Altarelli, M. Pepe; Perazzini, S.; Perret, P.; Perrin-Terrin, M.; Pescatore, L.; Pesen, E.; Pessina, G.; Petridis, K.; Petrolini, A.; Picatoste Olloqui, E.; Pietrzyk, B.; Pilar, T.; Pinci, D.; Pistone, A.; Playfer, S.; Plo Casasus, M.; Polci, F.; Poluektov, A.; Polycarpo, E.; Popov, A.; Popov, D.; Popovici, B.; Potterat, C.; Price, E.; Price, J. D.; Prisciandaro, J.; Pritchard, A.; Prouve, C.; Pugatch, V.; Navarro, A. Puig; Punzi, G.; Qian, W.; Rachwal, B.; Rademacker, J. H.; Rakotomiaramanana, B.; Rama, M.; Rangel, M. S.; Raniuk, I.; Rauschmayr, N.; Raven, G.; Redi, F.; Reichert, S.; Reid, M. M.; dos Reis, A. C.; Ricciardi, S.; Richards, S.; Rihl, M.; Rinnert, K.; Rives Molina, V.; Robbe, P.; Rodrigues, A. B.; Rodrigues, E.; Perez, P. Rodriguez; Roiser, S.; Romanovsky, V.; Romero Vidal, A.; Rotondo, M.; Rouvinet, J.; Ruf, T.; Ruiz, H.; Ruiz Valls, P.; Saborido Silva, J. J.; Sagidova, N.; Sail, P.; Saitta, B.; Salustino Guimaraes, V.; Sanchez Mayordomo, C.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santovetti, E.; Sarti, A.; Satriano, C.; Satta, A.; Saunders, D. M.; Savrina, D.; Schiller, M.; Schindler, H.; Schlupp, M.; Schmelling, M.; Schmidt, B.; Schneider, O.; Schopper, A.; Schubiger, M.; Schune, M. -H.; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Semennikov, A.; Sepp, I.; Serra, N.; Serrano, J.; Sestini, L.; Seyfert, P.; Shapkin, M.; Shapoval, I.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, V.; Shires, A.; Coutinho, R. Silva; Simi, G.; Sirendi, M.; Skidmore, N.; Skwarnicki, T.; Smith, N. A.; Smith, E.; Smith, E.; Smith, J.; Smith, M.; Snoek, H.; Sokoloff, M. D.; Soler, F. J. P.; Soomro, F.; Souza, D.; Souza De Paula, B.; Spaan, B.; Sparkes, A.; Spradlin, P.; Sridharan, S.; Stagni, F.; Stahl, M.; Stahl, S.; Steinkamp, O.; Stenyakin, O.; Stevenson, S.; Stoica, S.; Stone, S.; Storaci, B.; Stracka, S.; Straticiuc, M.; Straumann, U.; Stroili, R.; Subbiah, V. K.; Sun, L.; Sutcliffe, W.; Swientek, K.; Swientek, S.; Syropoulos, V.; Szczekowski, M.; Szczypka, P.; Szumlak, T.; T'Jampens, S.; Teklishyn, M.; Tellarini, G.; Teubert, F.; Thomas, C.; Thomas, E.; van Tilburg, J.; Tisserand, V.; Tobin, M.; Tolk, S.; Tomassetti, L.; Tonelli, D.; Topp-Joergensen, S.; Torr, N.; Tournefier, E.; Tourneur, S.; Tran, M. T.; Tresch, M.; Trisovic, A.; Tsaregorodtsev, A.; Tsopelas, P.; Tuning, N.; Garcia, M. Ubeda; Ukleja, A.; Ustyuzhanin, A.; Uwer, U.; Vacca, C.; Vagnoni, V.; Valenti, G.; Vallier, A.; Gomez, R. Vazquez; Vazquez Regueiro, P.; Vazquez Sierra, C.; Vecchi, S.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Vesterinen, M.; Viaud, B.; Vieira, D.; Vieites Diaz, M.; Vilasis-Cardona, X.; Vollhardt, A.; Volyanskyy, D.; Voong, D.; Vorobyev, A.; Vorobyev, V.; Voss, C.; de Vries, J. A.; Waldi, R.; Wallace, C.; Wallace, R.; Walsh, J.; Wandernoth, S.; Wang, J.; Ward, D. R.; Watson, N. K.; Websdale, D.; Whitehead, M.; Wicht, J.; Wiedner, D.; Wilkinson, G.; Williams, M. P.; Williams, M.; Wilschut, H. W.; Wilson, F. F.; Wimberley, J.; Wishahi, J.; Wislicki, W.; Witek, M.; Wormser, G.; Wotton, S. A.; Wright, S.; Wyllie, K.; Xie, Y.; Xing, Z.; Xu, Z.; Yang, Z.; Yuan, X.; Yushchenko, O.; Zangoli, M.; Zavertyaev, M.; Zhang, L.; Zhang, W. C.; Zhang, Y.; Zhelezov, A.; Zhokhov, A.; Zhong, L.; Zvyagin, A.

    2014-01-01

    Measuring cross-sections at the LHC requires the luminosity to be determined accurately at each centre-of-mass energy root s. In this paper results are reported from the luminosity calibrations carried out at the LHC interaction point 8 with the LHCb detector for root s = 2.76, 7 and 8TeV (proton-pr

  8. 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.

  9. Gamma measurements at LHCb

    CERN Document Server

    Cheung, Faye

    2016-01-01

    Recent measurements of the CKM angle g from charged and neutral B$\\rightarrow$ DK(*) decays, with a variety of D final states, are presented. The measurements are performed using proton-proton collision data corresponding to an integrated luminosity of 3 fb$^{-1}$ collected at the LHCb experiment during Run I of the LHC. The results of a combination of LHCb g measurements are discussed. The combined value of $\\gamma$ is $(70.9^{+7.1}_{-8.5})^{\\circ}$ and is the most precise measurement of $\\gamma$ from a single experiment.

  10. LHCb PDF measurements

    CERN Document Server

    Vesterinen, Mika

    2016-01-01

    The LHCb experiment covers a unique region of acceptance at forward rapidities in the high energy proton-proton collisions of the LHC. This means that measurements of particle production in LHCb are directly sensitive to the parton distribution functions at low Bj\\"orken-$x$ values. Several measurements of inclusive $W$ and $Z/\\gamma^{\\ast}$ production with the Run-I dataset are reported in these proceedings. Further measurements of $W$ and $Z/\\gamma^{\\ast}$ production in association with inclusive jets and $b$- and $c$-tagged jets are also reported.

  11. 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.

  12. Selection of LHCb Physics Results

    Directory of Open Access Journals (Sweden)

    Schmidt Burkhard

    2013-05-01

    Full Text Available LHCb is a dedicated flavour physics experiment at the LHC searching for physics beyond the Standard Model through precision measurements of CP-violating observables and the study of very rare decays of beauty- and charm-flavoured hadrons. In this article a selection of recent LHCb results is presented. Unless otherwise stated, the results are based on an integrated luminosity of 1 fb−1 accumulated during the year 2011 at √s = 7 TeV.

  13. LHCb animation

    CERN Multimedia

    CERN Video Productions

    2010-01-01

    Overview of the LHCb detector: LHCb's location underground in France, the detector's weight and dimentions, the basic design of LHCb, what it is designed to detect, number of scientists in the collaboration, the main questions the experiment hopes to answer and how.

  14. 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...

  15. LHCb Run 2 Trigger Performance

    CERN Document Server

    Sciascia, Barbara

    2016-01-01

    During the first long shutdown of the LHC (2013-2014, LS1), the LHCb detector remained essentially unchanged, while the trigger system has been completely revisited. Upgrades to the LHCb computing infrastructure have allowed for high quality decay information to be calculated by the software trigger making a separate offline event reconstruction unnecessary. Reaching the ultimate precision of the LHCb experiment already in real time as the data arrive has the power to transform the experimental approach to processing large quantities of data

  16. Eclipse plugins for LHCb software development

    CERN Document Server

    Astruc, Gregoire

    2011-01-01

    CERN LHCb Offline team, working on experiments around the LHC particle collider, had a number of tools to assist developers. LHCb projects use a domain-specific structure. Tools are always evolving and some team members started to look for ways to integrate those programs (most of them being CLIs) into more recent programming software like the Eclipse IDE. During this internship, a set of Eclipse plugins was created. They link the LHCb projects concepts to the ones in the IDE.

  17. The LHCb Turbo stream

    Science.gov (United States)

    Puig, A.

    2016-07-01

    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 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.

  18. 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.

  19. 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.

  20. The LHCb Detector Upgrade

    CERN Document Server

    Schindler, H

    2013-01-01

    The LHCb collaboration presented a Letter of Intent (LOI) to the LHCC in March 2011 for a major upgrading of the detector during Long Shutdown 2 (2018) and intends to collect a data sample of 50/fb in the LHC and High-Luminosity-LHC eras. The aim is to operate the experiment at an instantaneous luminosity 2.5 times above the present operational luminosity, which has already been pushed to twice the design value. Reading out the detector at 40MHz allows to increase the trigger efficiencies especially for the hadronic decay modes. 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.

  1. 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...

  2. 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.

  3. The LHCb experiment

    CERN Document Server

    Nakada, Tatsuya

    2000-01-01

    The LHCb experiment is designed to fully exploit the large number of b hadrons expected at the LHC energy and luminosity. The experiment is equipped with particle identification devices and can efficiently trigger events with different B-meson final states, allowing systematic studies of CP violation and other rare phenomena in the b hadron system with a high precision which could reveal physics beyond the Standard Model.

  4. 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.

  5. Associated vector boson production with b-jets at LHCb and Beam-Gas Vertexing at LHC for beam instrumentation

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00287090

    This thesis presents the cross-section measurements of associated vector bosons production with bottom quarks jets at 7 and 8 TeV of centre-of-mass energies. The first channel for cross-section measurement is the Z+b-jet with $Z/\\gamma^* \\to \\mu^+\\mu^-$ in proton-proton collisions at $\\sqrt s = \\text {7 TeV}$ using data collected by the LHCb experiment in 2011. The second channel is the $W + b\\overline b$, requiring two b-jets and one lepton. Apart from cross-section measurement this channel is also used to calculate limits of the Higgs boson produced in association with a vector boson and decaying into a pair of bottom or charm quarks. One of the main source of systematic errors in these analyses is the jet energy resolution and correction. Reduction of this error is achieved by performing a calibration of the neutral jet energy component, named neutral recovery, where empirical functions of the ratio between the charged particle energy of the jet and the particle momentum are determined. This method improv...

  6. 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...

  7. Performance of the LHCb Vertex Locator

    CERN Document Server

    Latham, T

    2012-01-01

    LHCb is a dedicated flavour physics experiment at the Large Hadron Collider (LHC) at CERN. The Vertex Locator (VELO) is an essential part of the LHCb detector, permitting precision measurements of the production and decay vertices of beauty and charm particles. The VELO consists of a series of silicon micro-strip detectors, arranged in two retractable halves. Positioned only 7 mm from the beam during normal operations, it must withstand very high levels of radiation. The performance of the LHCb VELO during the first year of LHC physics running is presented.

  8. 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.

  9. 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 ...

  10. Distributed data analysis in LHCb

    CERN Document Server

    Paterson, S K

    2008-01-01

    The LHCb distributed data analysis system consists of the Ganga job submission front-end and the DIRAC Workload and Data Management System (WMS). Ganga is jointly developed with ATLAS and allows LHCb users to submit jobs on several backends including: several batch systems, LCG and DIRAC. The DIRAC API provides a transparent and secure way for users to run jobs to the Grid and is the default mode of submission for the LHCb Virtual Organisation (VO). This is exploited by Ganga to perform distributed user analysis for LHCb. This system provides LHCb with a consistent, efficient and simple user experience in a variety of heterogeneous environments and facilitates the incremental development of user analysis from local test jobs to the Worldwide LHC Computing Grid. With a steadily increasing number of users, the LHCb distributed analysis system has been tuned and enhanced over the past two years. This paper will describe the recent developments to support distributed data analysis for the LHCb experiment on WLCG.

  11. LHCb Exotica and Higgs searches

    CERN Document Server

    Lucchesi, Donatella

    2016-01-01

    LHCb Collaboration has the unique opportunity to search for Higgs production and new physics in regions not accessible by the other LHC experiments. The latest results obtained by exploiting final states with b and c jets with or without an isolated lepton are presented.

  12. Beauty hadron decays at LHCb

    CERN Document Server

    Poluektov, Anton

    2016-01-01

    In these proceedings, I will report the recent results on properties, production and decays of beauty baryons, as well as measurements of B + c meson decays, based on data collected by the LHCb collaboration at the LHC collider in 2011–2012.

  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 Outreach example

    CERN Document Server

    Couturier, B

    2014-01-01

    The LHCb experiment is a general purpose spectrometer in the forward region optimized for precision studies of beauty and charm hadron properties. The volumes of data produced by the LHC make it possible to perform such precision measurements with only a fraction of the total LHCb dataset, making it an ideal playground for developing new types of masterclass exercises. We present here LHCb's first foray into the masterclass programme, in which students are taught how to make a 1% precision measurement of the D0 meson lifetime. The students learn to separate D0 mesons from the background in LHCb's vertex detector and build up a signal mass peak, before learning about how to use background sidebands to extract the signal properties in other variables of interest. They then perform a fit to measure the D0 lifetime, and discover that the result is biased by charm produced in the decays of B hadrons, which has an artificially long lifetime compared to charm produced directly in the proton-proton collision. Finally...

  15. Automated Voltage Control in LHCb

    CERN Document Server

    Granado Cardoso, L; Jacobsson, R

    2011-01-01

    LHCb is one of the 4 LHC experiments. In order to ensure the safety of the detector and to maximize efficiency, LHCb needs to coordinate its own operations, in particular the voltage configuration of the different subdetectors, according to the accelerator status. A control software has been developed for this purpose, based on the Finite State Machine toolkit and the SCADA system used for control throughout LHCb (and the other LHC experiments). This software permits to efficiently drive both the Low Voltage (LV) and High Voltage (HV) systems of the 10 different sub-detectors that constitute LHCb, setting each sub-system to the required voltage (easily configurable at run-time) based on the accelerator state. The control software is also responsible for monitoring the state of the Sub-detector voltages and adding it to the event data in the form of status-bits. Safe and yet flexible operation of the LHCb detector has been obtained and automatic actions, triggered by the state changes of the ...

  16. The LHCb trigger and its upgrade

    Science.gov (United States)

    Dziurda, A.

    2016-07-01

    The current LHCb trigger system consists of a hardware level, which reduces the LHC inelastic collision rate of 30 MHz, at which the entire detector is read out. In a second level, implemented in a farm of 20 k 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.

  17. PDF studies at LHCb

    Directory of Open Access Journals (Sweden)

    Bifani Simone

    2014-06-01

    Full Text Available Measurements of the Z and W boson production cross-sections provide important tests of the Standard Model at the LHC energies and allow the Parton Density Functions of the proton to be constrained. Electroweak bosons are reconstructed in several leptonic decay channels, and their cross-sections are reported using data collected in the forward region by the LHCb experiment at a centre of mass energy of √s = 7 TeV with an integrated luminosity of up to ∼ 1fb−1. Results are compared to NNLO predictions.

  18. Analiz ehffektivnosti perednej radiatsionnoj zashchity detektora CMS na LHC

    CERN Document Server

    Azhgirey, L S

    2002-01-01

    On the basis of numerical simulation results one analyzed the efficiency of the front radiation protection multipurpose CMS (Compact Muon Solenoid) detector on LHC. Paper presents the results of calculations of particle flow densities and of comparison with the protection perfect model. One investigated into secondary radiation field within detector range depending on configuration of protection. One proposes measures to improve protection of detector experimental region. Further ways to optimize design and composition of materials of protection are discussed

  19. 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.

  20. 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...

  1. 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 ...

  2. 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)

  3. The LHCb Turbo stream

    CERN Document Server

    Puig Navarro, Albert

    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. The LHCb Upgrade

    CERN Document Server

    Gallas, A

    2012-01-01

    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 LHC. The LHCb detector is a single-arm spectrometer with excellent tracking and particle identification capabilities. The operation and the results obtained from the data collected in 2010 and 2011 demonstrate that the detector is robust and functioning very well. In the next years, LHCb will measure a large number of interesting channels in heavy flavor decays. However, the limit of 1 fb−1 of data per year cannot be overcome without improving the detector. An upgraded spectrometer with a 40MHz readout and a much more flexible software-based triggering system will increase the data rate as well as the efficiency specially in the hadronic channels, widening our physics scope beyond that of heavy flavor. Here, the different possibilities under study for the different detectors are reviewed as well as the ongoing R&D activiti...

  5. The LHCb Turbo Stream

    CERN Document Server

    Benson, Sean; Vesterinen, Mika Anton; Williams, John Michael

    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 and discarding the raw event. 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 commissi...

  6. The LHCb Turbo Stream

    CERN Document Server

    Benson, Sean

    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...

  7. LHCb upgraded Muon System performance studies

    CERN Document Server

    Cogoni, V

    2016-01-01

    After the second Long Shutdown of the LHC scheduled for 2018–2020, LHCb will operate at an istantaneous luminosity of 2 · 10$^{33}$ cm$^{−2}$s$^{−1}$ and at a centre-of-mass energy of 14TeV. An overview of the LHCb Muon System Monte Carlo-based performance studies in upgrade conditions is presented.

  8. 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.

  9. 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...

  10. 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 ...

  11. LHCb Topological Trigger Reoptimization

    CERN Document Server

    Likhomanenko, Tatiana; Khairullin, Egor; Rogozhnikov, Alex; Ustyuzhanin, Andrey; 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. ...

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. LHCb results with vector bosons

    CERN Document Server

    Lucchesi, Donatella

    2016-01-01

    Measurements of electroweak bosons production provide an important test of the Standard Model at the LHC energies and allow the partonic content of the proton to be constrained. The LHCb forward acceptance is suited for measurements complementary to the other LHC experiments. W and Z bosons are reconstructed in e and μ leptonic final states using data samples collected at energies in the center of mass frame of √ s = 7 , 8 , 13 TeV corresponding to integrated luminosities of 1 , 2 , 0 . 29 fb − 1 respectively. Results on W + b / c quark and on W / Z + jets are also presented.

  17. 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.

  18. 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...

  19. LHCb: Velo

    CERN Multimedia

    LHCb, Collaboration

    2005-01-01

    Vertex Locator.Fine pitched silicon strip sensors are placed as close as possible to the LHC beam with a minimum amountof material between. The sensors are housed in secondary vacuum boxes which are retracted from the beam during LHC injection.

  20. 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.

  1. 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.

  2. Dark photons from charm mesons at LHCb

    Science.gov (United States)

    Ilten, Philip; Thaler, Jesse; Williams, Mike; Xue, Wei

    2015-12-01

    We propose a search for dark photons A' at the LHCb experiment using the charm meson decay D*(2007 )0→D0A'. At nominal luminosity, D*0→D0γ decays will be produced at about 700 kHz within the LHCb acceptance, yielding over 5 trillion such decays during Run 3 of the LHC. Replacing the photon with a kinetically mixed dark photon, LHCb is then sensitive to dark photons that decay as A'→e+e-. We pursue two search strategies in this paper. The displaced strategy takes advantage of the large Lorentz boost of the dark photon and the excellent vertex resolution of LHCb, yielding a nearly background-free search when the A' decay vertex is significantly displaced from the proton-proton primary vertex. The resonant strategy takes advantage of the large event rate for D*0→D0A' and the excellent invariant-mass resolution of LHCb, yielding a background-limited search that nevertheless covers a significant portion of the A' parameter space. Both search strategies rely on the planned upgrade to a triggerless-readout system at LHCb in Run 3, which will permit the identification of low-momentum electron-positron pairs online during data taking. For dark photon masses below about 100 MeV, LHCb can explore nearly all of the dark photon parameter space between existing prompt-A' and beam-dump limits.

  3. 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.

  4. 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...

  5. 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.

  6. Z Bosons in LHCb

    CERN Document Server

    AUTHOR|(CDS)2077480; Müller, Katharina; Anderson, Jonathan

    In this thesis several measurements of the $Z$ boson production cross section in the LHCb detector are presented. After an introduction with the description of the underlying theory; the detector and the properties of the collisions the machine provided to us in LHC run I in Chapter 1, in Chapter 2 the details of the $Z$ reconstruction in the $Z\\rightarrow\\mu^+\\mu^-$ final state is discussed. In Chapter 3 jets are added to the $Z$ bosons. Several aspects of jet reconstruction are presented and a cross section measurement for the associated production of $Z$ bosons with jets at $\\sqrt{s}=7$ TeV is presented for two transverse momentum thresholds of the jets. In Chapter 4 the capability of the LHCb detector to reconstruct charmed mesons is used to establish a $ZD^{0}$ and a $ZD^{+}$ signal and to measure the total cross section. In Chapter 5 the cross section of inclusive $Z$ boson production is measured at a low statistics sample of $3.3~\\text{pb}^{-1}$ at $\\sqrt{s}=2.76$ TeV.

  7. 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}\

  8. The LHCb VELO upgrade

    CERN Document Server

    Collins, P; Poikela, T; Crossley, M; Kucharczyk, M; Whitehead, M; Dumps, R; Mountain, R; Artuso, M; Rodrigues, E; Tlustos, L; Papadelis, A; Buytaert, J; Blusk, S; Parkes, C; Xing, Z; Eklund, L; Coco, V; Michel, T; Campbell, M; Bowcock, T J V; Wang, J C; Akiba, K; Gligorov, V; Huse, T; Llin, L F; Gandelman, M; Plackett, R; Esperante, D; Maneuski, D; Bayer, F; Llopart, X; Alexander, M; Gallas, A; Nichols, M; van Beuzekom, M G; John, M

    2011-01-01

    The LHCb experiment at the LHC plans to massively increase its data taking capabilities by running at a higher luminosity with a fully upgraded detector around 2016. This scheme is independent of (but compatible with) the plans for the SLHC upgrades. The silicon detector will be upgraded to provide a 40 MHz readout and to be able to cope with the increased radiation environment. This paper describes the options currently under consideration. A highlight of the R\\&D so far undertaken is a beam test during summer 2009 using the Timepix chip to track charged particles. Preliminary results are presented, including a measurement of the resolution achieved by the 55 mu m pitch pixel array of better than 9.5 mu m for perpendicular tracks and 55 mu m for angled tracks. (C) 2010 Elsevier B.V. All rights reserved.

  9. 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.

  10. 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...

  11. LHCb Upgrade: Scintillating Fibre Tracker

    Science.gov (United States)

    Tobin, Mark

    2016-07-01

    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.

  12. 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...

  13. 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...

  14. 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.

  15. LHCb Upgrade: Scintillating Fibre Tracker

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-11

    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.

  16. 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.

  17. Commissioning and performance of the LHCb outer tracker

    NARCIS (Netherlands)

    Pellegrino, Antonio

    2011-01-01

    The LHCb experiment is a single arm spectrometer, designed to study CP violation in B-decays at the Large Hadron Collider (LHC). It is crucial to accurately and efficiently detect the charged decay particles, in the high-density particle environment of the LHC. For this, the Outer Tracker was constr

  18. 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...

  19. 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...

  20. 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 \

  1. 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...

  2. 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.

  3. 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...

  4. 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 $A_p = (-0.39 \\pm 0.22 \\pm 0.08)$%.

  5. Interview with LHCb Physicist Tara Shears on March 30th, 2010

    CERN Multimedia

    LHCb OUTREACH

    2010-01-01

    From the LHCb control center Tara describes the excitement on the day and answers questions about LHCb. What LHCb is studying, how one of the biggest mysteries of the universe is why anti-matter behaves differently than matter, the theory of "b physics," the big bang and what happened between matter and anti-matter in the early moments of our universe, definition of the beauty particle, why LHCb is studying it, what is the difference between LHCb detector and the larger detectors on the LHC.

  6. The upstream tracker for the LHCb upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Steinkamp, Olaf, E-mail: olafs@physik.uzh.ch

    2016-09-21

    The LHCb collaboration is planning a comprehensive upgrade of the experiment for the long shutdown of the LHC in 2019/20. As part of this upgrade, the tracking station in front of the LHCb dipole magnet will be replaced by a new planar four-layer silicon micro-strip detector with 40 MHz readout and silicon sensors with finer granularity and improved radiation hardness. Key design aspects of this new Upstream Tracker are described and a brief overview of the status of the project is given.

  7. New results on collectivity with LHCb

    CERN Document Server

    Kopecna, Renata

    2017-01-01

    Two-particle angular correlations are studied in $pp$ collisions at $\\sqrt s = 13~ \\text {TeV}$, collected with the LHCb detector at the LHC. The LHCb detector provides measurement in the very forward region, $2 < \\eta < 5$. This region is complementary to other experiments and allows to explore low Bjorken-$x$ region. The correlations are studied as a function of difference in pseudorapidity $( \\Delta \\eta)$ and azimuthal angle $(\\Delta \\phi)$ in several $p_T$ and activity classes. Proton-proton collisions are studied using two datasets corresponding to minimum-bias sample and a sample obtained via a dedicated trigger to study the highest-activity events.

  8. LHCb commissioning and readiness for first data

    CERN Document Server

    Voss, Helge

    2009-01-01

    LHCb has been installed by spring 2008, followed by intensive testing and commissioning of the system in order to be ready for first data taking. Despite the horizontal geometry of the LHCb detector it was possible to collect over one million useful cosmic events that allowed a first time alignment of the sub-detectors. Moreover events from beam dumps during the LHC synchronisation tests provided very useful data for further time and spacial alignment of the detector. Here we present an overview of our commissioning activities, the current status and an outlook on the startup in 2009.

  9. The four main LHC experiments

    CERN Multimedia

    AC Team

    1999-01-01

    This diagram shows the locations of the four main experiments (ALICE, ATLAS, CMS and LHCb) that will take place at the LHC. Located between 50 m and 150 m underground, huge caverns have been excavated to house the giant detectors. The SPS, the final link in the pre-acceleration chain, and its connection tunnels to the LHC are also shown.

  10. LHCb long term plans beyond the current upgrade

    CERN Document Server

    Teubert, Frederic

    2016-01-01

    HL-LHC can provide up to 2×1034 Hz cm−2 instantaneous luminosity to LHCb without signifi- cant loses for the other interaction points at the LHC ring, and be able to integrate up to 300 fb−1 before the insertion magnets need replacement. There is a clear and strong physics case for an LHCb second upgrade (LHCb phase 2 upgrade) during the long shutdown currently scheduled in 2030. Very rare decays, or exotic searches are limited by statistics. Some of the most interesting CKM measurements are not limited by systematic uncertainties. Some of the improved detector technologies needed for this second upgrade, and other ideas discussed in these proceedings, could already be implemented during the long shutdown in 2024-2025 (LHCb phase 1b upgrade).

  11. LHCb on track

    CERN Multimedia

    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.

  12. Tracking Performance at LHCb

    CERN Multimedia

    Wandernoth, S

    2010-01-01

    We present the tracking performance at LHCb by showing the mass resolution, impact parameter resolution and proper time resolution of the first data taken at LHCb. Furthermore several methods to estimate the tagging efficiency on data are presented.

  13. 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.

  14. Charmed baryons at LHCb

    CERN Document Server

    Naik, Paras

    2016-01-01

    The LHCb detector is an excellent instrument for studying the production and decay of charmed baryons in $pp$ collisions, due to efficient triggering mechanisms that capture the copious production of $c\\overline{c}$ at the Large Hadron Collider. The LHCb experiment and its charmed baryon results from LHCb are detailed, with a description of our future plans.

  15. Proposed Inclusive Dark Photon Search at LHCb

    Science.gov (United States)

    Ilten, Philip; Soreq, Yotam; Thaler, Jesse; Williams, Mike; Xue, Wei

    2016-06-01

    We propose an inclusive search for dark photons A' at the LHCb experiment based on both prompt and displaced dimuon resonances. Because the couplings of the dark photon are inherited from the photon via kinetic mixing, the dark photon A'→μ+μ- rate can be directly inferred from the off-shell photon γ*→μ+μ- rate, making this a fully data-driven search. For run 3 of the LHC, we estimate that LHCb will have sensitivity to large regions of the unexplored dark-photon parameter space, especially in the 210-520 MeV and 10-40 GeV mass ranges. This search leverages the excellent invariant-mass and vertex resolution of LHCb, along with its unique particle-identification and real-time data-analysis capabilities.

  16. Interview with Andrei Golutvin, LHCb Spokesperson

    CERN Multimedia

    CERN Video Productions

    2009-01-01

    Questions : 1. How does it feel to be the Spokesperson of a large worldwide collaboration as LHCb at the very moment when the LHC is going to produce the first data? 2. Is your detector ready for the data taking? 3. Did you take advantage of the long shut down? 4. What was the LHCb detector designed for and why is it different from the other ones? 5. What can you expect to find at 3.5 TeV and later at 7 per beam? 6. Is Andrei Sakarov's theory on matter and antimatter asymetry a guiding line for you? 7. What is going to happen in the LHCb control room on collision day?

  17. Proposed Inclusive Dark Photon Search at LHCb.

    Science.gov (United States)

    Ilten, Philip; Soreq, Yotam; Thaler, Jesse; Williams, Mike; Xue, Wei

    2016-06-24

    We propose an inclusive search for dark photons A^{'} at the LHCb experiment based on both prompt and displaced dimuon resonances. Because the couplings of the dark photon are inherited from the photon via kinetic mixing, the dark photon A^{'}→μ^{+}μ^{-} rate can be directly inferred from the off-shell photon γ^{*}→μ^{+}μ^{-} rate, making this a fully data-driven search. For run 3 of the LHC, we estimate that LHCb will have sensitivity to large regions of the unexplored dark-photon parameter space, especially in the 210-520 MeV and 10-40 GeV mass ranges. This search leverages the excellent invariant-mass and vertex resolution of LHCb, along with its unique particle-identification and real-time data-analysis capabilities.

  18. Inclusive Dark Photon Search at LHCb

    CERN Document Server

    Ilten, Philip; Thaler, Jesse; Williams, Mike; Xue, Wei

    2016-01-01

    We propose an inclusive search for dark photons $A'$ at the LHCb experiment based on both prompt and displaced di-muon resonances. Because the couplings of the dark photon are inherited from the photon via kinetic mixing, the dark photon $A' \\to \\mu^+ \\mu^-$ rate can be directly inferred from the off-shell photon $\\gamma^* \\to \\mu^+ \\mu^-$ rate, making this a fully data-driven search. For Run 3 of the LHC, we estimate that LHCb will have sensitivity to large regions of the unexplored dark-photon parameter space, especially in the 210-520 MeV and 10-40 GeV mass ranges. This search leverages the excellent invariant-mass and vertex resolution of LHCb, along with its unique particle-identification and real-time data-analysis capabilities.

  19. 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...

  20. Event shape based global event cuts for the LHCb trigger

    CERN Document Server

    Kolchanova, Alena; CERN. Geneva. Department

    2016-01-01

    In 2019 LHCb will have one of the biggest upgrades of all LHC experiments. The project aims to study event shape variables for the LHCb trigger. Event shape variables are used to help identify events as having a higher likelihood of containing a beauty hadron within the LHCb acceptance from Minimum bias. Samples of each process are generated using the Pythia program. Fox Wolfram Moments, sphericity and thrust are applied to the data by selecting events with pseudorapidity $2.2 $ 2 GeV.

  1. 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.

  2. 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...

  3. 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...

  4. 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.

  5. The LHCb computing data challenge DC06

    Energy Technology Data Exchange (ETDEWEB)

    Nandakumar, R [Science and Technology Facilities Council (United Kingdom); Jimenez, S G [University Rovira i Virgili (Spain); Adinolfi, M [H. H. Wills Physics Laboratory, Bristol (United Kingdom); Bernet, R [Universitat Zurich (Switzerland); Blouw, J [Physikalisches Institut, Heidelberg (Germany); Bortolotti, D; Carbone, A; M' Charek, B [Universita and INFN, Bologna (Italy); Perego, D L [INFN sez. Milano-Bicocca (Italy); Pickford, A [University of Glasgow (United Kingdom); Potterat, C [LPHE-IPEP, Lausanne (Switzerland); Miguelez, M S [Universidad de Santiago de Compostela (Spain); Bargiotti, M; Castellani, G; Charpentier, P; Closier, J [CERN (Switzerland); Brook, N [University of Bristol (United Kingdom); Casajus, A; Diaz, R Graciani [Universitat de Barcelona (Spain); Cioffi, C [University of Oxford (United Kingdom)], E-mail: r.nandakumar@rl.ac.uk (and others)

    2008-07-15

    The worldwide computing grid is essential to the LHC experiments in analysing the data collected by the detectors. Within LHCb, the computing model aims to simulate data at Tier-2 grid sites as well as non-grid resources. The reconstruction, stripping and analysis of the produced LHCb data will pimarily place at the Tier-1 centres. The computing data challenge DC06 started in May 2006 with the primary aims being to exercise the LHCb computing mod and to produce events which will be used for analyses in the forthcoming LHCb physics book. This paper gives an overview of the LHCb computing model and addresses the challenges and experiences during DC06. The management of the production of Monte Carlo data on the LCG was done using the DIRAC worklad management system which in turn uses the WLCG infrastructure and middleware. We shall report on the amount of data simulated during DC06, including the performance of the sites used. The paper will also summarise the experience gained during DC06, in particular he distribution of data to the Ter-1 sits and the access to this data.

  6. 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...

  7. 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.

  8. 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.

  9. Measuring top quark production asymmetries at LHCb

    CERN Document Server

    Gauld, Rhorry

    2013-01-01

    Simulated data is studied to assess the potential sensitivity of LHCb to measure top quark production asymmetries, via the single particle pseudorapidity asymmetry in muonic decays of top quarks, with current integrated luminosities of 1, 2 fb$^{−1}$ at 7, 8 TeV LHC centre of mass energies respectively. This includes estimates of reconstruction effects as well as theoretical errors present in signal modelling at the next-to-leading order.

  10. 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.

  11. Event Index - an LHCb Event Search System

    CERN Document Server

    Ustyuzhanin, Andrey

    2015-01-01

    During LHC Run 1, the LHCb experiment recorded around 1011 collision events. This paper describes Event Index | an event search system. Its primary function is to quickly select subsets of events from a combination of conditions, such as the estimated decay channel or number of hits in a subdetector. Event Index is essentially Apache Lucene [1] optimized for read-only indexes distributed over independent shards on independent nodes.

  12. 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...

  13. LHCb VELO upgrade

    Science.gov (United States)

    Hennessy, Karol

    2017-02-01

    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 2×1033 cm-2 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 55×55 μm2 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 CO2 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.

  14. 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...

  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. Status of the LHCb VErtex LOcator

    CERN Document Server

    Palacios, J P

    2003-01-01

    LHCb is a single arm spectrometer at the LHC. It is dedicated to the study of CP violation in the B-hadron system. The VErtex LOcator (VELO) is a silicon microstrip detector providing accurate measurements of event primary and secondary vertices, impact parameters, and tracks. The second level trigger decision of LHCb is mainly based on information from a full readout of the VELO. This document gives a general introduction to LHCb as a context for a more extensive description of the VELO. The VELO design emphasises the need for precise reconstruction of tracks down to momenta of a few GeV. The VELO operates inside the LHC beam-pipe, and the sensors, the hybrids, and the foil separating the primary and secondary vacuua must be built with the minimum possible material. The R-$\\phi$ strip layout is optimised for efficient trigger operation and precise measurements at the smallest radii. The performance must be maintained in the harsh radiation environment close to the LHC beams. These issues have led to a choice...

  17. 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.

  18. 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

  19. LHC Report: Level best

    CERN Multimedia

    Mike Lamont for the LHC team

    2012-01-01

    The LHCb experiment is special: there is a limit to the number of the events the detector can handle per bunch crossing. Consequently the maximum luminosity provided in 2012 has been around 4 x1032 cm-2s-1 (compared to the maximum of 7.7 x1033 cm-2s-1 seen by ATLAS and CMS). Nonetheless LHCb still wants to integrate as much luminosity as possible.    To meet LHCb's requirements a luminosity leveling technique is used. A machine setup is chosen that would give a peak luminosity well above the required maximum if the beams are collided head-on at LHCb's interaction point. This peak luminosity is then reduced to the required maximum by moving the two beams transversely apart at the interaction point. As the beam current goes down during a fill, the beams can be moved together in small increments to keep the collision rate constant throughout the fill. In practice, when the LHC goes into collisions in LHCb, the initial luminosity is safely below LHCb's demanded le...

  20. LHCb velo detector

    CERN Multimedia

    Patrice Loïez

    2001-01-01

    Photo 01 : L. to r.: D. Malinon, Summer Student, J. Libby, Fellow, J. Harvey, Head of CERN LHCb group, D. Schlatter, Head of the EP Division in front of the LHCb velo detector test beam (on the right). Photo 02 : L. to r.: J. Harvey, D. Schlatter, W. Riegler (staff), H.J. Hilke, LHCb Technical Coordinator in front of the muon chamber test beam

  1. Charmed baryons from LHCb

    CERN Document Server

    Ogilvy, Stephen

    2015-01-01

    The vast amount of $c\\overline{c}$ production that can be recorded by the LHCb detector makes it an ideal environment to study the hadronic production of charmed baryons, along with the properties of their decays. We briefly describe the LHCb experiment and the triggering mechanisms it uses for recording charm production. Previous charmed baryon results from LHCb are detailed, with a description of the future plans for the charmed baryon programme.

  2. 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 ...

  3. LHC restart 2016

    CERN Multimedia

    CERN Audiovisual production

    2016-01-01

    Footage of first injection of proton beam in the LHC machine, that took place on Friday March 25, 2016, at the injection energy of 450 GeV. Interview to Mike Lamont, head of LHC operations and of Fabiola Gianotti, CERN Director General. General footage of the Cern Control Centre on first beam 2016 day, the LHC machine operators and Engineers in Charge at work, relevant screens summarizing the machine parametres. Views of the LHC tunnel and the 4 main experimental caverns with views of the ATLAS, CMS, ALICE and LHCb detectors. 3 D animations of the CERN accelerator complex, from the Linac, to the PS, SPS and the LHC. VOICE OVER : Alex Brown

  4. 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 ...

  5. 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.

  6. 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.

  7. 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

  8. Hadron Spectroscopy, exotics and $B_c^+$ physics at LHCb

    CERN Document Server

    Dey, Biplab

    2016-01-01

    The LHCb experiment is designed to study properties and decays of heavy flavored hadrons produced from $pp$ collisions at the LHC. During Run~1, it has recorded the world's largest data sample of beauty and charm hadrons, enabling precision spectroscopy studies of such particles. Several important results obtained by LHCb, such as the discovery of the first pentaquark states and the first unambiguous determination of the $Z_c(4430)^-$ as an exotic state, have dramatically increased the interest on spectroscopy of heavy hadrons. An overview of the latest LHCb results on the subject, including the discovery of four strange exotic states decaying as $X \\to J/\\psi \\phi$, is presented. LHCb has also made significant contributions to the field of $B_c^+$ physics, the lowest bound state of the heavy flavor $\\bar{b}$ and $c$ quarks. A synopsis of the the latest results is given.

  9. Hadron Spectroscopy, exotics and BC + physics at LHCb

    Science.gov (United States)

    Dey, Biplab

    2016-11-01

    The LHCb experiment is designed to study properties and decays of heavy flavored hadrons produced from pp collisions at the LHC. During Run 1, it has recorded the world's largest data sample of beauty and charm hadrons, enabling precision spectroscopy studies of such particles. Several important results obtained by LHCb, such as the discovery of the first pentaquark states and the first unambiguous determination of the Zc (4430) - as an exotic state, have dramatically increased the interest in spectroscopy of heavy hadrons. An overview of the latest LHCb results on the subject, including the discovery of four strange exotic states decaying as X → J/ψϕ, is presented. LHCb has also made significant contributions to the field of BC + physics, the lowest bound state of the heavy flavor ̅b and c quarks. A synopsis of the latest results is given.

  10. Novel strategies at LHCb for particle identification arXiv

    CERN Document Server

    Ferrari, Fabio

    The LHCb experiment at the Large Hadron Collider (LHC) is performing high precision measurements in the flavour sector. An excellent performance of the particle identification (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 identification 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.

  11. LHCb results on penta(tetra)-quark search

    CERN Document Server

    Kucharczyk, Marcin

    2016-01-01

    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 spec- troscopy studies of beauty and charm hadrons. The latest results on spectroscopy of conventional and exotic hadrons are reviewed, such as the discovery of the first charmonium pentaquark states in the $J/\\psi p$system or the confirmation of resonant nature of the $Z(4430)^-$ mesonic state. LHCb has also made significant contributions to determination of the quantum numbers for the $X(3872)$ state and to exclude the existence of the $X(5568)$ tetraquark candidate. The LHCb results described in the present document have dramatically increased the interest on spectroscopy of heavy hadrons.

  12. Absolute luminosity measurements at LHCb

    CERN Document Server

    Hopchev, Plamen

    2011-01-01

    Absolute luminosity measurements are of general interest for colliding-beam experiments at storage rings. These measurements are necessary to determine the absolute cross-sections of reaction processes and are valuable to quantify the performance of the accelerator. LHCb has applied two methods to determine the absolute scale of its luminosity measurements for proton-proton collisions at the LHC running at a centre-of-mass energy of 7 TeV. In addition to the classic ``van der Meer'' scan method a novel technique has been developed which makes use of direct imaging of the individual beams using both proton-gas and proton-proton interactions. The beam imaging method is made possible by the high resolution of the LHCb vertex detector and the close proximity of the detector to the beams, and allows beam parameters such as positions, angles and widths to be determined. We describe both methods and compare the two results. In addition, we present the techniques used to transport the absolute luminosity measurement ...

  13. Calibration samples for particle identification at LHCb in Run 2

    CERN Document Server

    Lupton, Olli; Sciascia, Barbara; Gligorov, Vladimir

    2016-01-01

    The strategy for data-driven determination of particle identication performance at LHCb has changed signicantly from Run 1 to Run 2 of the LHC. This note outlines these changes, explains the rationale behind them and summarises the new system and conguration.

  14. 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; Barandela Pazos, MdC; 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; Büchler-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; dos Reis, A C; Dovbnya, A; Du Pree, T; Duval, P -Y; Dwyer, L; Dzhelyadin, R; Eames, C; Easo, S; Egede, U; Egorychev, V; Eisele, F; Eisenhardt, S; Eklund, L; Esperante Pereira, D; Estève, L; Eydelman, S; Fanchini, E; F¨arber, 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, Vladimir V; Göbel, C; Golubkov, D; Golutvin, A; Gomes, A; Grabalosa Gándara, M; Graciani Diaz, R; Granado Cardoso, L A; Graugés, 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; Iglesias Escudero, C; 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; Lefran¸cois, 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 (Chiojdeanu), C; Pavel (Nicorescu), C; Pazos Alvarez, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perego, D L; Pérez-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; Souza De Paula, B; 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.

  15. 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.

  16. The LHCb Starterkit

    CERN Document Server

    Bel, Lennaert

    2017-01-01

    The LHCb Starterkit is an initiative by members of the LHCb collaboration, providing up-to- date tutorials and interactive workshops for new collaboration members to get acquainted with the software used. Centrally organizing this has improved the efficiency of new collaboration members, and made it easier for people to quickly start developing code.

  17. LHCb calorimeter electronics. Photon identification. Calorimeter calibration

    CERN Document Server

    Machefert, F

    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 preshower, 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 th...

  18. 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...

  19. 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...

  20. LHCb Computing experience with first data

    Energy Technology Data Exchange (ETDEWEB)

    Adinolfi, Marco [H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom)

    2010-07-01

    After several years of experience with Grid production and Analysis dealing with simulated data, the first LHC collision data (as of March 2010) have confronted the LHCb Computing Model with real data. The LHCb Computing Model is somewhat different from the traditional MONARC hierarchical model used by the other LHC experiments: first pass reconstruction, as well as further reprocessing, are performed at a set of 7 Tier-1 sites (including CERN), while Tier2 sites are used mainly for simulation productions. User analysis is performed at LHCb Analysis Centres for which the timeline is the 7 Tier-1s. Event reconstruction is enabled only after thorough checking of the quality of the data. In case there is a need for a new calibration or alignment of the detector, new calibration constants are generated and certified, before the reconstruction can proceed. Analysis relies on the concept of reduced datasets (so-call stripped datasets) that are centrally produced at the 7 Tier-1's and then distributed to all the analysis centres. We shall review the performance of this model with the 2010 real data, and give an outlook for possible modifications to be put in place for the 2011 run. (author)

  1. The LHCb trigger system: performance and outlook

    CERN Document Server

    Stracka, Simone

    2014-01-01

    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, of which only 5 kHz can be written to storage for offline analysis. The trigger system plays a key role in selecting signal events and rejecting background, and is comprised of a hardware level (L0), reducing the rate to the maxi- mum at which the detector can be fully read out, and a High Level Trigger (HLT) -implemented in software and deployed on a farm of roughly 25000 parallel processing cores- responsible for reducing the rate to the 5 kHz which can be processed offline. The LHCb trigger system allowed LHCb to run at twice its design luminosity in 2012, and performed beyond the nominal design in terms of signal yields. The design and performance of the selection algorithms are discussed in the context of the 2012 data taking, and planned improvements for RunII are presented

  2. 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.

  3. 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.

  4. SIMD studies in the LHCb reconstruction software

    CERN Document Server

    Campora Perez, D H

    2015-01-01

    During the data taking process in the LHC at CERN, millions of collisions are recorded every second by the LHCb Detector. The LHCb Online computing farm, counting around 15000 cores, is dedicated to the reconstruction of the events in real-time, in order to filter those with interesting Physics. The ones kept are later analysed $Offline$ in a more precise fashion on the Grid. This imposes very stringent requirements on the reconstruction software, which has to be as efficient as possible. Modern CPUs support so-called vector-extensions, which extend their Instruction Sets, allowing for concurrent execution across functional units. Several libraries expose the Single Instruction Multiple Data programming paradigm to issue these instructions. The use of vectorisation in our codebase can provide performance boosts, leading ultimately to Physics reconstruction enhancements. In this paper, we present vectorisation studies of significant reconstruction algorithms. A variety of vectorisation libraries are analysed a...

  5. Upgrade of the LHCb VELO detector

    Science.gov (United States)

    Williams, Mark

    2017-01-01

    The LHCb experiment is a single-arm forward spectrometer optimised for performing heavy-flavour physics analyses, using proton-proton collisions provided by the LHC machine. A major upgrade of the LHCb experiment will take place prior to the start of Run 3 operations in 2021. The upgraded Vertex Locator (VELO) is an essential component of this upgrade. Its main role is to enable high precision track and vertex reconstruction, with data-driven readout to the software trigger at 40 MHz, in the higher-luminosity environment of Run 3. To achieve this goal, significant improvements are planned with respect to the current detector, including a switch from microstrips to pixels, upgraded electronics, and a new cooling system. I will briefly motiviate the need for an upgrade, describe the main aspects of the VELO upgrade design, and show highlights of recent sensor characterisation studies using the CERN SPS test beam.

  6. The upgrade of the LHCb Vertex Locator

    CERN Document Server

    Bird, T

    2014-01-01

    The LHCb experiment is set for a significant upgrade, which will be ready for Run~3 of the LHC in 2020. This upgrade will allow LHCb to run at a significantly higher instantaneous luminosity and collect an integrated luminosity of $50\\,\\text{fb}^{-1}$ by the end of Run~4. In this process the Vertex locator (VELO) detector will be upgraded to a pixel-based silicon detector. The upgraded VELO will improve upon the current detector by being closer to the beam and having lower material modules with microchannel cooling and a thinner RF-foil. Simulations have shown that it will maintain its excellent performance, even after the radiation damage caused by collecting an integrated luminosity of $50\\,\\text{fb}^{-1}$.

  7. 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.

  8. 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...

  9. The LHCb Trigger: Present and Future

    CERN Document Server

    Aaij, R

    2012-01-01

    LHCb is a single arm spectrometer covering the pseudo-rapidity range between 1.9 and 4.9, and has been optimised to perform flavour physics measurements at the LHC. The present two stage trigger system is able to select charm and beauty decay products with high efficiency due the highly inclusive approach of triggering on partially reconstructed decays and the use of a novel multivariate classifier at the second stage. The trigger can select both leptonic and purely hadronic decays. The performance of the trigger is determined from the data itself without having to rely on Monte-Carlo simulation and is presented. LHCb has recently submitted their upgrade LOI, which mainly aims at profiting from much larger luminosities by moving towards a single fully software based trigger. The upgrade strategy and expected performance are presented.

  10. Soft QCD Measurements at LHC

    CERN Document Server

    Tasevsky, Marek; The ATLAS collaboration

    2017-01-01

    Results of recent soft QCD measurements by LHC experiments ALICE, ATLAS, CMS, LHCb, LHCf and TOTEM are reported. The measurements include total, elastic and inelastic cross sections, inclusive and identified particle spectra, underlying event and particle correlations in all three collision systems: pp, pPb and PbPb.

  11. LHCb Injected Beam Accidents

    CERN Document Server

    Appleby, R B

    2009-01-01

    The LHCb (point 8) interaction region is sensitive to beam orbit errors arising from magnet setting errors on injection. In this report, beam accident scenarios under injection for LHCb are described, focusing on ultra- fast error injection scenarios for the interaction straight correctors and dipoles. Beam 1 and beam 2 accident scenarios are considered, where the errors can lead to beam orbits striking the LHCb vacuum chamber or elements of the machine. The required thresholds for magnet current interlocks are calculated to avoid machine and detector risk.

  12. 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).

  13. 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.

  14. Abundantly and rarely expressed Lhc protein genes exhibit distinct regulation patterns in plants.

    Science.gov (United States)

    Klimmek, Frank; Sjödin, Andreas; Noutsos, Christos; Leister, Dario; Jansson, Stefan

    2006-03-01

    We have analyzed gene regulation of the Lhc supergene family in poplar (Populus spp.) and Arabidopsis (Arabidopsis thaliana) using digital expression profiling. Multivariate analysis of the tissue-specific, environmental, and developmental Lhc expression patterns in Arabidopsis and poplar was employed to characterize four rarely expressed Lhc genes, Lhca5, Lhca6, Lhcb7, and Lhcb4.3. Those genes have high expression levels under different conditions and in different tissues than the abundantly expressed Lhca1 to 4 and Lhcb1 to 6 genes that code for the 10 major types of higher plant light-harvesting proteins. However, in some of the datasets analyzed, the Lhcb4 and Lhcb6 genes as well as an Arabidopsis gene not present in poplar (Lhcb2.3) exhibited minor differences to the main cooperative Lhc gene expression pattern. The pattern of the rarely expressed Lhc genes was always found to be more similar to that of PsbS and the various light-harvesting-like genes, which might indicate distinct physiological functions for the rarely and abundantly expressed Lhc proteins. The previously undetected Lhcb7 gene encodes a novel plant Lhcb-type protein that possibly contains an additional, fourth, transmembrane N-terminal helix with a highly conserved motif. As the Lhcb4.3 gene seems to be present only in Eurosid species and as its regulation pattern varies significantly from that of Lhcb4.1 and Lhcb4.2, we conclude it to encode a distinct Lhc protein type, Lhcb8.

  15. 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, Vladimir; 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

    2014-01-01

    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...

  16. 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...

  17. 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...

  18. 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

  19. 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.

  20. 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

  1. LHCb VELO Tracking Resolutions

    CERN Multimedia

    Alexander, Michael

    2011-01-01

    The excellent tracking performance of the Vertex Locator (VELO) at LHCb is presented. The resolutions it achieves on single hits, impact parameters, and primary vertex positions are shown, with particular attention paid to measurement of impact parameters.

  2. LHCb magnet coils arrive

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    Each of the two coils for the LHCb magnet 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 eight turns of conductor, wound from a single length (approx. 290 m) of extruded aluminium. The coils have arrived at CERN; one of them is seen here being unloaded above the LHCb experimental cavern.

  3. 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.

  4. CP violation in charm and beauty decays at LHCb

    Energy Technology Data Exchange (ETDEWEB)

    Pepe Altarelli, M., E-mail: monica.pepe.altarelli@cern.ch

    2013-08-15

    LHCb is a dedicated heavy flavour physics precision experiment at the LHC searching for New Physics (NP) beyond the Standard Model (SM) through the study of very rare decays of beauty and charm-flavoured hadrons and precision measurements of CP-violating observables. In this review I will present a selection of recent precision measurements of CP-violating observables in the decays of beauty and charm-flavoured hadrons. These measurements are based on an integrated luminosity of up to 1.0 fb{sup −1} collected by LHCb in 2011.

  5. 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.

  6. LHCb experiment physics programme and status of detector

    CERN Document Server

    Ajaltouni, Ziad J

    2002-01-01

    LHCb is a dedicated experiment designed to search for CP violation in both neutral and charged B meson decays at the LHC proton-proton collider. A general review of the main B decay channels is given by stressing on the physical parameters which can be measured and interpreted in the framework of the standard CKM matrix. On the experimental side, emphasis will be put on the different sub-detectors which enter the whole detector, the main role of the trigger system made out from four levels and finally, the global performance of the LHCb detector.

  7. The VELO (VErtex LOcator) at the LHCb experiment

    CERN Document Server

    De Capua, S.

    2008-01-01

    The LHCb silicon vertex locator (VELO) is an array of silicon planes installed in a retractable roman pot system, which will enable the LHCb experiment to reconstruct and trigger on b-hadrons produced in collisions at the LHC. The VELO will be also used to attempt measuring the absolute luminosity with a novel method based on vertex reconstruction of beam gas interactions. In this paper the VELO system, its construction and the results from the commissioning phase are presented. The options for a possible upgraded detector are also discussed.

  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. 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...

  10. LHCb: Measuring B to mu mu K

    CERN Multimedia

    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.

  11. 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.

  12. 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.

  13. Alignment of the LHCb tracking system

    CERN Document Server

    Märki, Raphael

    2011-01-01

    The LHCb experiment at the LHC is dedicated to precision measurements of $CP$-violation and rare decays in the $b$ and $c$ sectors. The experiment features a tracking system consisting of silicon strip detectors and straw tube drift chambers up- and downstream of the magnet to precisely measure the vertex position and the momentum resolution of the particles travelling through the detector. An important ingredient to the track parameter resolution is the spatial alignment of the tracking system on which we report here.

  14. Vertexing and Tracking Software at LHCb

    CERN Document Server

    Bowen, Espen Eie

    2015-01-01

    The LHCb experiment is a dedicated heavy flavour experiment at the LHC. Its primary goal is to search for indirect evidence of New Physics in CP violation and rare decays of beauty and charm hadrons. The detector includes a high granularity silicon-strip vertex detector, a silicon-strip detector upstream of the magnet and three stations of silicon-strip detectors and straw drift tubes downstream of the magnet. The software used to perform the track reconstruction and primary vertex reconstruction is described in detail along with a discussion of its performance.

  15. Performance of the LHCb Tracking Detectors

    CERN Document Server

    Tobin, Mark

    2013-01-01

    The LHCb experiment is making high-precision measurements of CP violation and searching for New Physics using the enormous flux of beauty and charm hadrons produced at the LHC. The detector includes a high precision tracking system consisting of a silicon-strip vertex detector surrounding the pp interaction region, a large-area silicon-strip detector located upstream of a dipole magnet, and three stations of silicon-strip detectors and straw drift tubes placed downstream. The performance of the individual silicon-strip detectors will be discussed together with the overall performance of the full tracking system.

  16. 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...

  17. 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).

  18. LHCb Computing Resources: 2017 requests

    CERN Document Server

    Bozzi, Concezio

    2016-01-01

    This document presents an assessment of computing resources needed by LHCb in 2017, as resulting from the accumulated experience in Run2 data taking and recent changes in the LHCb computing model parameters.

  19. 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...

  20. Italian Physical Society Novel Muon Identification Algorithms for the LHCb upgrade

    CERN Document Server

    Cogoni, V

    2017-01-01

    After the second Long Shutdown of the LHC scheduled for 2020, LHCb will operate at an istantaneous luminosity of $2·10^{33} cm^{−2}s^{−1}$ and at a centre of mass energy of 14 TeV. In this context, an overview of the possible new algorithms for the muon identification for the LHCb Upgrade is illustrated here. In particular, the performance on combinatorial background rejection is shown, together with the extrapolations to upgrade conditions.

  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 - 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.

  3. 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...

  4. Revision of the LHCb limit on Majorana neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Shuve, Brian; Peskin, Michael E.

    2016-12-16

    We revisit the recent limits from LHCb on a Majorana neutrino N in the mass range 250–5000 MeV [R. Aaij et al. (LHCb Collaboration), Phys. Rev. Lett. 112, 131802 (2014).]. These limits are among the best currently available, and they will be improved soon by the addition of data from Run 2 of the LHC. LHCb presented a model-independent constraint on the rate of like-sign leptonic decays, and then derived a constraint on the mixing angle V μ 4 based on a theoretical model for the B decay width to N and the N lifetime. The model used is unfortunately unsound. We revise the conclusions of the paper based on a decay model similar to the one used for the τ lepton and provide formulas useful for future analyses.

  5. Flavour tagging of neutral B mesons at the LHCb detector

    CERN Document Server

    Jacoby, C

    2002-01-01

    The LHCb (a L ar ge Hadr on Col lider Be auty Exp eriment) c ol lab or ation is involve d in an exp erimental r ese ar ch pr o gr am aiming to p erform, starting in 2007, pr e cise me asur ements of the CP symmetry violation in b -hadr on de c ays pr o duc e d at the fu- tur e LHC c ol lider at CERN. In many CP violation studies at LHCb, it is imp ortant to know the avour state of neutr al B mesons at the time of pr o duction (i.e. to know if it is a B 0 or a B 0 ). This so-c al le d avour tagging is studie d in this do cument. In p articular, the p erformanc e of the curr ent LHCb tagging algorithm is analyze d and optimize d wher ep ossible.

  6. LHCb Build and Deployment Infrastructure for run 2

    Science.gov (United States)

    Clemencic, M.; Couturier, B.

    2015-12-01

    After the successful run 1 of the LHC, the LHCb Core software team has taken advantage of the long shutdown to consolidate and improve its build and deployment infrastructure. Several of the related projects have already been presented like the build system using Jenkins, as well as the LHCb Performance and Regression testing infrastructure. Some components are completely new, like the Software Configuration Database (using the Graph DB Neo4j), or the new packaging installation using RPM packages. Furthermore all those parts are integrated to allow easier and quicker releases of the LHCb Software stack, therefore reducing the risk of operational errors. Integration and Regression tests are also now easier to implement, allowing to improve further the software checks.

  7. 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...

  8. Searching supersymmetry at the LHCb with displaced vertices

    CERN Document Server

    De Campos, F; Magro, M B; Restrepo, D

    2008-01-01

    Supersymmetric theories with bilinear R-parity violation can give rise to the observed neutrino masses and mixings. One important feature of such models is that the lightest supersymmetric particle might have a sufficiently large lifetime to give rise to detached vertices. Working in the framework of supergravity models we analyze the potential of the LHCb experiment to search for supersymmetric models exhibiting bilinear R-parity violation. We show that the LHCb experiment can probe a large fraction of the $m_0 \\otimes m_{1/2}$ being able to explore gluino masses up to 1.3 TeV. The LHCb discover potential for this kind of models is similar to the ATLAS and CMS ones in the low luminosity phase of operation of the LHC.

  9. Revision of the LHCb limit on Majorana neutrinos

    Science.gov (United States)

    Shuve, Brian; Peskin, Michael E.

    2016-12-01

    We revisit the recent limits from LHCb on a Majorana neutrino N in the mass range 250-5000 MeV [1 R. Aaij et al. (LHCb Collaboration), Phys. Rev. Lett. 112, 131802 (2014)., 10.1103/PhysRevLett.112.131802]. These limits are among the best currently available, and they will be improved soon by the addition of data from Run 2 of the LHC. LHCb presented a model-independent constraint on the rate of like-sign leptonic decays, and then derived a constraint on the mixing angle Vμ 4 based on a theoretical model for the B decay width to N and the N lifetime. The model used is unfortunately unsound. We revise the conclusions of the paper based on a decay model similar to the one used for the τ lepton and provide formulas useful for future analyses.

  10. Fixed target measurements at LHCb for cosmic rays physics arXiv

    CERN Document Server

    Graziani, Giacomo

    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 $\\sqrt{s_{\\scriptscriptstyle\\rm NN}} \\sim 100$ 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.

  11. A large Scintillating Fibre Tracker for LHCb

    Science.gov (United States)

    Greim, R.

    2017-02-01

    The LHCb experiment will be upgraded during LHC Long Shutdown 2 to be able to record data at a higher instantaneous luminosity. The readout rate is currently limited to 1 MHz by the Level 1 trigger. In order to achieve the target integrated luminosity of 50 fb-1 during LHC Run 3, all subdetectors have to be read out by a 40 MHz trigger-less readout system. Especially, the current tracking detectors downstream of the LHCb dipole magnet suffer from large detector dead times and a small granularity in the Outer Tracker, which consists of proportional straw tubes. Therefore, the Downstream Tracker will be replaced by a Scintillating Fibre Tracker with Silicon Photomultiplier readout. The total sensitive area of 340 m2 is made up of 2.5 m long fibre mats consisting of six staggered layers of 250 μm thin scintillating fibres. The scintillation light created by the charged particles traversing the fibre mats is transported to the fibre ends via total internal reflection and detected by state-of-the-art multi-channel SiPM arrays. This paper presents the detector concept, design, challenges, custom-made readout chips, as well as laboratory and beam test results.

  12. Radiation damage in the LHCb Vertex Locator

    CERN Document Server

    Affolder, A; Alexander, M; Ali, S; Artuso, M; Benton, J; van Beuzekom, M; Bjørnstad, P M; Bogdanova, G; Borghi, S; Bowcock, T J V; Brown, H; Buytaert, J; Casse, G; Collins, P; De Capua, S; Dossett, D; Eklund, L; Farinelli, C; Garofoli, J; Gersabeck, M; Gershon, T; Gordon, H; Harrison, J; Heijne, V; Hennessy, K; Hutchcroft, D; Jans, E; John, M; Ketel, T; Lafferty, G; Latham, T; Leflat, A; Liles, M; Moran, D; Mous, I; Oblakowska-Mucha, A; Parkes, C; Patel, G D; Redford, S; Reid, M M; Rinnert, K; Rodrigues, E; Schiller, M; Szumlak, T; Thomas, C; Velthuis, J; Volkov, V; Webber, A D; Whitehead, M; Zverev, E

    2013-01-01

    The LHCb Vertex Locator (VELO) is a silicon strip detector designed to reconstruct charged particle trajectories and vertices produced at the LHCb interaction region. During the first two years of data collection, the 84 VELO sensors have been exposed to a range of fluences up to a maximum value of approximately $\\rm{45 \\times 10^{12}\\,1\\,MeV}$ neutron equivalent ($\\rm{1\\,MeV\\,n_{eq}}$). At the operational sensor temperature of approximately $-7\\,^{\\circ}\\rm{C}$, the average rate of sensor current increase is 18$\\mu$ A per $\\rm{fb^{-1}}$, in excellent agreement with predictions. The silicon effective bandgap has been determined using current versus temperature scan data after irradiation, with an average value of $E_{g}=1.16\\pm0.03\\pm0.04\\,\\rm{eV}$ obtained. The first observation of n-on-n sensor type inversion at the LHC has been made, occurring at a fluence of around $15 \\times 10 ^{12}$ of $1\\,\\rm{MeV\\,n_{eq}}$. The only n-on-p sensors in use at the LHC have also been studied. With an initial fluence of ap...

  13. Latest LHCb results

    Directory of Open Access Journals (Sweden)

    Martinelli Maurizio

    2014-01-01

    Full Text Available The LHCb experiment is one of the major research projects at the Large Hadron Collider. Its acceptance and instrumentation is optimised to perform high-precision studies of flavour physics and particle production in a unique kinematic range at unprecedented collision energies. Using large data samples accumulated in the years 2010-2012, the LHCb collaboration has conducted a series of measurements providing a sensitive test of the Standard Model and strengthening our knowledge of flavour physics, QCD and electroweak processes. The status of the experiment and some of its recent results are presented here.

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. New LHCb Management readies for run 2 challenges

    CERN Document Server

    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...

  19. Installation and commissioning of a high-efficiency and high-resolution straw tube tracker for the LHCb experiment

    NARCIS (Netherlands)

    Pellegrino, Antonio

    2010-01-01

    The LHCb experiment is a single arm spectrometer, designed to study CP violation in B-decays at the Large Hadron Collider (LHC). It is crucial to accurately and efficiently detect the charged decay particles, in the high-density particle environment of the LHC. For this, the Outer Tracker (OT) was c

  20. Determination of the aperture of the LHCb VELO RF foil

    CERN Document Server

    Ferro-Luzzi, M; Wallace, C

    2014-01-01

    Hadronic interactions in the material of the LHCb Vertex Locator are used to determine the aperture that the RF foil presents to the LHC beam. The aperture is found to be 4.5 mm, to be compared with the nominal value of 5.5 mm. The dierence is well within the tolerance of 2.4 mm considered for the safety of the beam.

  1. Lifetime unbiased beauty and charm triggers at LHCb

    CERN Document Server

    Kenzie, Matthew William

    2016-01-01

    This note describes the use of lifetime unbiased triggers in LHCb's High Level Trigger system, implemented during Run 2 of LHC data collection. This is the first time such a strategy has been employed to exclusively trigger on signal candidates in a lifetime unbiased way at a hadron collider. It provides samples of charm and beauty hadrons whose lifetime acceptance due to the trigger requirements is uniform. Consequently, these triggers are suitable for time-dependent measurements and calibration purposes.

  2. The Beam Conditions Monitor of the LHCb Experiment

    CERN Document Server

    Ilgner, Ch; Lieng, M; Nedos, M; Sauerbrey, J; Schleich, S; Spaan, B; Warda, K; Wishahi, J

    2010-01-01

    The LHCb experiment at the European Organization for Nuclear Research (CERN) is dedicated to precision measurements of CP violation and rare decays of B hadrons. Its most sensitive components are protected by means of a Beam Conditions Monitor (BCM), based on polycrystalline CVD diamond sensors. Its configuration, operation and decision logics to issue or remove the beam permit signal for the Large Hadron Collider (LHC) are described in this paper.

  3. Readiness of the LHCb experiment for first data

    CERN Document Server

    Lai, Adriano

    2009-01-01

    This paper deals with the present status of the LHCb detector, with special emphasis on the commissioning tests and analysis. The detector response has been widely tested by means of cosmic particle events and with the very first beam before the LHC rupture in September 2008. Some of the results of these studies are reported. Finally, plans on the use of the first beam data, expected in 2009, are shortly presented.

  4. Selected CPV Results from LHCb Run 1 and Prospects for CKM $\\gamma $ Angle Measurements in Run 2

    CERN Document Server

    Oblakowska-Mucha, Agniezka

    2016-01-01

    The LHCb detector is a single-arm forward spectrometer that collects data at the LHC, designed for studies of flavour physics with high precision. In this review, a few selected results regarding CP violation are discussed with particular emphasis on the CKM angle measurements. This sum- mary covers results based on the data collected by the LHCb detector during 2011 and 2012 proton–proton LHC runs at the centre-of-mass ener- gies of 7 and 8 TeV, respectively. Some remarks on prospects for analyses foreseen in the ongoing LHC Run 2 are also presented

  5. 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 ...

  6. 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

  7. 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.

  8. 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 ...

  9. LHCb flavour tagging performance

    CERN Document Server

    Calvi, M; Musy, M

    2003-01-01

    In CP violation measurements, the most accurate determination of the B flavour of neutral and charged B-mesons is necessary. In this note we summarize the tagging performances for the LHCb experiment, using different approaches and studying different decay channels.

  10. LHCb VELO Upgrade

    CERN Multimedia

    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...

  11. Fixed-target physics at LHCb arXiv

    CERN Document Server

    Maurice, Emilie

    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.

  12. $J/\\psi$ Production Study at the LHCb Experiment

    CERN Document Server

    Qian, W; Schune, M-H; Robbe, P

    2010-01-01

    The large hadron collider (LHC) at Conseil European Pour Recherches Nucleaires (CERN) in Geneva is the largest particle physics accelerator. Protonproton collisions up to a center-of-mass energy of 14 TeV to be produced at the LHC will offer great opportunity to address most fundamental questions in physics. The LHCb experiment is one of the four main experiments at the LHC. Dedicated to b physics studies, the primary goal of the LHCb experiment is to explore possible New Physics beyond the Standard Model through the studies of rare decays of charm and beauty-flavoured hadrons and precision measurements of CP-violating observables. Even at its first running phase, the enormous number of $J/\\psi$ particles to be collected by the LHCb detector will allow us to realize some very interesting physics studies on charmonium productions. The measurement may shed new light on the long standing puzzle in understanding the mechanism of quarkonia production in hadron-hadron collisions. In this thesis, studies of $J/\\psi$...

  13. J/ψ production study at the LHCb experiment

    CERN Document Server

    Qian, W; Schune, M H

    The large hadron collider (LHC) at Conseil European Pour Recherches Nucleaires (CERN) in Geneva is the largest particle physics accelerator. Proton-proton collisions up to a center-of-mass energy of 14 TeV to be produced at the LHC will offer great opportunity to address most fundamental questions in physics. The LHCb experiment is one of the four main experiments at the LHC. Dedicated to b physics studies, the primary goal of the LHCb experiment is to explore possible New Physics beyond the Standard Model through the studies of rare decays of charm and beauty-flavoured hadrons and precision measurements of CP-violating observables. Even at its first running phase, the enormous number of J/ψ particles to be collected by the LHCb detector will allow us to realize some very interesting physics studies on charmonium productions. The measurement may shed new light on the long standing puzzle in understanding the mechanism of quarkonia production in hadron-hadron collisions. In this thesis, studies of J/ψ pro...

  14. 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...

  15. 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...

  16. 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.

  17. 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 $C_{J/\\psi K^0_S} = 0.03 \\pm 0.09 (\\text{stat})\\pm 0.01 (\\text{syst})$.

  18. 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.

  19. Optimisation of the LHCb detector

    CERN Document Server

    Hierck, R

    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.

  20. 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.

  1. Particles are back in the LHC!

    CERN Multimedia

    2009-01-01

    Last weekend (23-25 October) particles once again entered the LHC after the one-year interruption following the incident of September 2008. Particles travelled through one sector clockwise and one anticlockwise. ALICE and LHCb, the two experiments sitting along the portion of the beam lines in question, were able to observe the first effects of real beams in the machine.

  2. Recent Electroweak Results from the LHC

    CERN Document Server

    Helary, Louis; The ATLAS collaboration

    2016-01-01

    Slides for conference Aspen 2016. The talk is about recent Electroweak results at the LHC. It is focused on multi-boson physics and boson EWK production. It is supposed to summarize results from ATLAS, CMS and LHCb, but given the topic it contains only material from ATLAS and CMS.

  3. The LHCb RICH system: current detector performance and status of the upgrade program

    CERN Document Server

    Fiorini, Massimiliano

    2016-01-01

    LHCb is a precision experiment devoted to the study of CP violation and rare decays of b and c quarks, and to the search for new physics beyond the Standard Model at the Large Hadron Collider (LHC) at CERN. The Ring-Imaging Cherenkov (RICH) system is a key component of the LHCb experiment: it consists of two RICH detectors that provide charged particle identification over a wide momentum range (2-100 GeV/c) and angular acceptance (15-300 mrad). The LHCb RICH system has been performing extremely well during Run 1 and is providing the LHCb experiment also in Run 2 with a robust, reliable and precise particle identification system. Performance of the RICH detectors measured from data will be presented, with special reference to its dependence on calibration parameters and event multiplicities. The LHCb experiment is preparing for an upgrade during the second LHC long shutdown (2019-2020) in order to fully exploit the LHC flavour physics potential. A five-fold increase in instantaneous luminosity is foreseen reac...

  4. Electroweak physics at the LHC

    Science.gov (United States)

    Berryhill, J.; Oh, A.

    2017-02-01

    The Large Hadron Collider (LHC) has completed in 2012 its first running phase and the experiments have collected data sets of proton-proton collisions at center-of-mass energies of 7 and 8 TeV with an integrated luminosity of about 5 and 20 {{fb}}-1, respectively. Analyses of these data sets have produced a rich set of results in the electroweak sector of the standard model. This article reviews the status of electroweak measurements of the ATLAS, CMS and LHCb experiments at the LHC.

  5. LHCb: Beam Pipe portrait

    CERN Multimedia

    LHCb, Collaboration

    2005-01-01

    The proton beams circulate in the accelerator in Ultra High Vacuum to make them interact only with each other when colliding at the interaction point. A special beam pipe "holds" the vacuum where they pass through the LHCb detector: it has to be mechanically very strong to stand the difference in pressure between the vacuum inside it and the air in the cavern but also be as transparent as possible for the particles originating in the proton−proton collisions.

  6. LHCb: Beam Pipe

    CERN Multimedia

    LHCb, Collaboration

    2005-01-01

    The proton beams circulate in the accelerator in Ultra High Vacuum to make them interact only with each other when colliding at the interaction point. A special beam pipe "holds" the vacuum where they pass through the LHCb detector:it has to be mechanically very strong to stand the difference in pressure between the vacuum inside it and the air in the cavern but also be as transparent as possible for the particles originating in the proton−proton collisions.

  7. LHCb GPU Acceleration Project

    CERN Document Server

    AUTHOR|(SzGeCERN)744808; Campora Perez, Daniel Hugo; Neufeld, Niko; Vilasis Cardona, Xavier

    2016-01-01

    The LHCb detector is due to be upgraded for processing high-luminosity collisions, which will increase the load on its computation infrastructure from 100 GB/s to 4 TB/s, encouraging us to look for new ways of accelerating the Online reconstruction. The Coprocessor Manager is our new framework for integrating LHCb’s existing computation pipelines with massively parallel algorithms running on GPUs and other accelerators. This paper describes the system and analyzes its performance.

  8. 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.

  9. 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.

  10. The Large Hadron Collider (LHC): The Energy Frontier

    Science.gov (United States)

    Brianti, Giorgio; Jenni, Peter

    The following sections are included: * Introduction * Superconducting Magnets: Powerful, Precise, Plentiful * LHC Cryogenics: Quantum Fluids at Work * Current Leads: High Temperature Superconductors to the Fore * A Pumping Vacuum Chamber: Ultimate Simplicity * Vertex Detectors at LHC: In Search of Beauty * Large Silicon Trackers: Fast, Precise, Efficient * Two Approaches to High Resolution Electromagnetic Calorimetry * Multigap Resistive Plate Chamber: Chronometry of Particles * The LHCb RICH: The Lord of the Cherenkov Rings * Signal Processing: Taming the LHC Data Avalanche * Giant Magnets for Giant Detectors

  11. Tracking and Alignment of the LHCb detector

    CERN Document Server

    Martinelli, Maurizio

    2014-01-01

    The LHCb experiment is designed to study $B$-decays at the LHC. This purpose is achieved by means of an outstanding track momentum resolution and excellent particle identification. The performance of the detector exceeds expectations, and the physics program of the collaboration is extended to the study of charm decays, QCD and electroweak physics. Both tracking and alignment play a key role for obtaining these results. The tracking efficiency in this high-occupancy environment has been measured during LHC Run I (2010-2012) to be larger than 95% over a wide range of momentum and pseudo-rapidity. The alignment of the detector is based on a Kalman filter fit of the tracks and provides an uncertainty on the momentum scale below 1 x 10$^{-4}$ and a momentum resolution of about 0.4%. These results allowed one to achieve high-precision mass measurements of many charm and $B$ hadrons so far. Starting from Run II of the LHC, the running conditions will continue to push the performance of the detector to its limits. A...

  12. 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...

  13. Full offline reconstruction in real-time with the LHCb detector

    CERN Document Server

    Dziurda, Agnieszka

    2016-01-01

    This document describes the novel, unique in High Energy Physics, real-time alignment and calibration of the full LHCb detector. The LHCb experiment has been designed as a dedicated heavy flavour physics experiment focused on the reconstruction of c and b hadrons. The LHCb detector is a single-arm forward spectrometer, which measures proton-proton interactions at the LHC. The operational bunch crossing rate is several orders of magnitude above the current abilities of data recording and storage. Therefore, a trigger system has been implemented to reduce this rate to an acceptable value. The LHCb trigger system has been redesigned during the 2013-2015 long shutdown, achieving oine-quality alignment and calibration online. It also allows analyses to be performed entirely at the trigger level. In addition, having the best performing reconstruction in the trigger gives the possibility to fully use the particle identification selection criteria and greatly increases the eciency, in particular for the selection of...

  14. 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.

  15. 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.

  16. 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.

  17. Rare beauty and charm decays at LHCb

    Directory of Open Access Journals (Sweden)

    Albrecht Johannes

    2013-05-01

    Full Text Available Rare heavy flavor decays are an ideal place to search for the effects of potential new particles that modify the decay rates or the Lorentz structure of the decay vertices. The LHCb experiment, a dedicated heavy flavour experiment at the LHC at CERN. It has recorded the worlds largest sample of heavy meson and lepton decays. The status of the rare decay analyses with 1 fb−1 of √s = 7 TeV and 1.1 fb−1 of √s = 8 TeV of pp–collisions collected by the LHCb experiment in 2011 and 2012 is reviewed. The worlds most precise measurements of the angular structure of B0 → K*0μ+μ− and B+ → K+μ+μ− decays is discussed, as well as the isospin asymmetry measurement in B → K(*μ+μ− decays. The first evidence for the very rare decay Bs0 → µ+µ− is presented together with the most stringent upper exclusion limits on the branching fraction of decays of B0, D0 and Ks0 mesons into two muons. This note finishes with the discussion of searches for lepton number and lepton flavor violating τ decays.

  18. The LHCb level 1 vertex trigger

    CERN Document Server

    Koratzinos, M

    1999-01-01

    Summary form only given. The Level 1 Vertex trigger of LHCb has certain features that make it unique amongst the LHC experiment trigger schemes: The problem it addresses is a reduction factor of 25 for minimum bias events while retaining good efficiency for signal B events. The best way to achieve such reduction factors is to rely on the most striking property of those B events, the long decay time of the B particles. The trigger therefore has to reconstruct the event around the interaction region and tag signal events using topological criteria. An accurate vertex detector is one of the key components of LHCb and a natural choice for providing the data for such a triggering scheme. The algorithm for the reconstruction of the event is complicated and not readily parallelisable in its totality. We are therefore proposing an architecture that resembles a high-level trigger architecture, where the event building function is performed by a switch network and each event is processed by a single processor, part of ...

  19. 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...

  20. SIMD studies in the LHCb reconstruction software

    Science.gov (United States)

    Cámpora Pérez, Daniel Hugo; Couturier, Ben

    2015-12-01

    During the data taking process in the LHC at CERN, millions of collisions are recorded every second by the LHCb Detector. The LHCb Online computing farm, counting around 15000 cores, is dedicated to the reconstruction of the events in real-time, in order to filter those with interesting Physics. The ones kept are later analysed Offline in a more precise fashion on the Grid. This imposes very stringent requirements on the reconstruction software, which has to be as efficient as possible. Modern CPUs support so-called vector-extensions, which extend their Instruction Sets, allowing for concurrent execution across functional units. Several libraries expose the Single Instruction Multiple Data programming paradigm to issue these instructions. The use of vectorisation in our codebase can provide performance boosts, leading ultimately to Physics reconstruction enhancements. In this paper, we present vectorisation studies of significant reconstruction algorithms. A variety of vectorisation libraries are analysed and compared in terms of design, maintainability and performance. We also present the steps taken to systematically measure the performance of the released software, to ensure the consistency of the run-time of the vectorised software.

  1. The Tracker in the Trigger of LHCb

    CERN Document Server

    Hommels, L B A; Merk, M; Tuning, N

    2006-01-01

    Situated at the LHC, the LHCb experiment is to measure B meson decay with high statistics. Its primary goals are the establishment of CP violation parameters with high precision, and the study of rare B meson decays to look for physics processes beyond the Standard Model. In this thesis, an overview is given on the Outer Tracker (OT) subdetector of the LHCb experiment. The requirements on efficiency, resolution, occupancy and radiation hardness are discussed. The detector design and readout electronics of the OT, a gas filled detector, are presented. To meet the requirements, straw tube cathodes of 4.9mm inner diameter surround the anode wires. The tubes are filled with an Argon based counting gas at atmospheric pressure, allowing for a channel resolution better then 200mum. To limit multiple scattering, the OT is built from lightweight composite materials, resulting in a momentum resolution of dp/p < 0.6% for p between 0 and 150 GeV/c. From extensive ageing tests involving single channels as well as entir...

  2. Studies of Soft QCD at LHCb

    CERN Document Server

    Meissner, Marco

    2013-01-01

    The LHCb detector at the LHC has a unique peudorapidity coverage (2 < $\\eta$ < 5) which allows to perform soft QCD measurements in the kinematic forward region where QCD models have large uncertainties. Selected analyses on soft QCD measurements in $pp$ collisions are summarised in these proceedings. The energy flow has been measured separately for different event classes allowing to probe multi-parton interactions at large $\\eta$. The measured prompt hadron ratios are important for hadronisation models, while the $\\bar{p}/p$ is a good observable to test models of baryon number transport. Charm production has been studied to determine cross-sections and production ratios. All measurements are compared to Monte Carlo simulation or theory predictions.

  3. Radiation hardness of the LHCb Outer Tracker

    Energy Technology Data Exchange (ETDEWEB)

    Eijk, D. van, E-mail: dveijk@nikhef.nl [Nikhef, Amsterdam (Netherlands); Bachmann, S. [Physikalisches Institut, Heidelberg (Germany); Bauer, Th. [Nikhef, Amsterdam (Netherlands); Faerber, Ch.; Bien, A. [Physikalisches Institut, Heidelberg (Germany); Coco, V. [Nikhef, Amsterdam (Netherlands); Deckenhoff, M. [Technische Universitaet Dortmund (Germany); Dettori, F. [Nikhef, Amsterdam (Netherlands); Ekelhof, R. [Technische Universitaet Dortmund (Germany); Gersabeck, E. [Physikalisches Institut, Heidelberg (Germany); Karbach, T.M. [Technische Universitaet Dortmund (Germany); Koopman, R.; Kozlinskiy, A. [Nikhef, Amsterdam (Netherlands); Langenbruch, Ch.; Linn, Ch. [Physikalisches Institut, Heidelberg (Germany); Merk, M. [Nikhef, Amsterdam (Netherlands); Meissner, M. [Physikalisches Institut, Heidelberg (Germany); Morawski, P. [H. Niewodniczanski Institute of Nuclear Physics, Cracow (Poland); Pellegrino, A. [Nikhef, Amsterdam (Netherlands); Serra, N. [Physik-Institut, Universitaet Zuerich (Switzerland); and others

    2012-09-01

    This paper presents results on the radiation hardness of the LHCb Outer Tracker (OT) during LHC operation in 2010 and 2011. Modules of the OT have shown to suffer from ageing effects that lead to gain loss, after irradiation in the laboratory. Under irradiation at moderate intensities an insulating layer is formed on the anode wire of the OT straw cells. This ageing effect is caused by contamination of the counting gas due to outgassing of the glue used in the construction of the OT modules. Two methods to monitor gain stability in the OT are presented: module scans with radioactive sources and the study of hit efficiency as a function of amplifier threshold. No gain loss is observed after receiving 1.3 fb{sup -1} of integrated luminosity corresponding to an integrated charge of 0.055 C/cm in the hottest spot of the detector.

  4. Radiation hardness of the LHCb Outer Tracker

    CERN Document Server

    van Eijk, D; Bauer, T; Färber, C; Bien, A; Coco, V; Deckenhoff, M; Dettori, F; Ekelhof, R; Gersabeck, E; Karbach, T M; Koopman, R; Kozlinskiy, A; Langenbruch, C; Linn, C; Merk, M; Meissner, M; Morawski, P; Pellegrino, A; Serra, N; Seyfert, P; Spaan, B; Swientek, S; Storaci, B; Tuning, N; Szczekowski, M; Uwer, U; Visser, E; Wiedner, D; Witek, M

    2012-01-01

    This paper presents results on the radiation hardness of the LHCb Outer Tracker (OT) during LHC operation in 2010 and 2011. Modules of the OT have shown to suffer from ageing effects that lead to gain loss, after irradiation in the laboratory. Under irradiation at moderate intensities an insulating layer is formed on the anode wire of the OT straw cells. This ageing effect is caused by contamination of the counting gas due to outgassing of the glue used in the construction of the OT modules. Two methods to monitor gain stability in the OT are presented: module scans with radioactive sources and the study of hit efficiency as a function of amplifier threshold. No gain loss is observed after receiving 1.3 fb−1 of integrated luminosity corresponding to an integrated charge of 0.055 C/cm in the hottest spot of the detector.

  5. Performance of the LHCb Outer Tracker

    CERN Document Server

    Arink, R; 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.

  6. Heavy quark spectroscopy at LHCb

    CERN Document Server

    INSPIRE-00165164

    2015-01-01

    The analysis of $3.0 fb^{-1}$ of proton-proton collisions collected with the LHCb detector has yielded a broad range of results in spectroscopy of conventional and exotic hadrons with heavy quark(s) inside. We review the LHCb results which have been obtained over the last year.

  7. 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...

  8. 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...

  9. 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...

  10. LHCb: Universal Logging System for LHCb

    CERN Multimedia

    Nikolaidis, F; Garnier, J-C; Neufeld, N

    2010-01-01

    In a large-scale IT infrastructure such as the LHCb Online system many applications are running on thousands of machines producing many GBs of logs every day. Although most of the logs are just routine logs, some of them may indicate an attack, a malfunction or provide vital debugging information. Due to their volume only automatisation of the analysis of the logs can provide us with an efficient way to handle all of these logs, ensuring that even the most rare logs will be processed. We present a centralized logging system which allow us to do in-depth analysis of every log. The description of the architecture includes information from how we integrate logging from many devices to a centralized server using syslog and in particular how a correlation can indicate an attack. Special emphasis is given both to security monitoring as well as to the logs that indicate developing malfunctions. To secure our network we have deployed the most known of HIDS, NIDS , LIDS (Host , Network, Log intrusion detection). Each ...

  11. 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 (...

  12. Performance and operational aspects of LHCb's VELO and ST

    CERN Document Server

    Rodrigues, E

    2014-01-01

    The LHCb experiment aims at the search for New Physics with the study of rare heavy hadron decays and the study of CP violation in the decays of charm and beauty hadrons. The detector, a single-arm spectrometer at the Large Hadron Collider (LHC), Geneva, includes a high precision tracking system: a silicon-strip vertex detector, a silicon-strip tracker upstream of the magnet, and three stations of silicon-strip detectors and straw tubes downstream of the magnet. The excellent performance of the silicon-strip detectors during the first run of the LHC is detailed, focussing on the most recent studies. Highlights will include alignment, cluster finding efficiency, single hit resolution, and impact parameter and vertex resolutions, with updates based on recent results from the 2012 LHC running.

  13. The Performance of the Outer Tracker Detector at LHCb

    CERN Document Server

    Storaci, Barbara

    2011-01-01

    The LHCb experiment is a single arm spectrometer, designed to study CP violation in $B$-decays at the Large Hadron Collider (LHC). It is crucial to accurately and efficiently detect the charged decay particles, in the high-density particle environment of the LHC. For this, the Outer Tracker was constructed, consisting of $\\sim$55,000 straw tubes, covering in total an area of 360 m2 of double layers. A precise drift-time measurement results in a single hit resolution of 220 $\\mu$m, at an average occupancy up to 10% and at 1 MHz trigger rate. At the time of the conference, the detector has been commissioned with almost two years of LHC beam collision data. After dedicated studies to establish timing and spatial alignment, the first results on the detector performance (efficiency, resolutions, etc.) have been obtained.

  14. Top Production at LHCb

    CERN Multimedia

    Santana Rangel, Murilo

    2015-01-01

    Single and pair top production in the forward direction at the LHC allows for precision tests of the Standard Model. The observation of top quarks in 7 and 8 TeV data and prospects for precision measurements are shown.

  15. 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.

  16. Rare decays at LHCb

    CERN Document Server

    Lafferty, George

    2015-01-01

    We review recent results from the LHCb experiment on studies of particle decays that are forbidden or rare in the Standard Model. The studies include searches for lepton flavour violating decays of the $\\tau$ lepton and the $B$ and $D$ mesons, and of $B$ and $D$ meson decays that would be mediated by Majorana neutrinos. Results are also presented for the rare processes $B_s \\to \\mu^+\\mu^-$ and $B^0 \\to \\mu^+\\mu^-$, $D^0 \\to \\pi^+\\pi^-\\mu^+\\mu^-$, $b \\to s\\gamma$ transitions, and $B \\to K^{(*)}\\mu^+\\mu^-$.

  17. Automated Grid Monitoring for LHCb through HammerCloud

    CERN Document Server

    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.

  18. The LHCb Vertex Locator (VELO) Pixel Detector Upgrade

    CERN Document Server

    Buchanan, Emma

    2017-01-01

    The LHCb experiment is designed to perform high-precision measurements of CP violation and the decays of beauty and charm hadrons at the Large Hadron Collider (LHC) at CERN. There is a planned upgrade during Long Shutdown 2 (LS2), expected in 2019, which will allow the detector to run at higher luminosities by transforming the entire readout to a trigger-less system. This will include a substantial upgrade of the Vertex Locator (VELO), the silicon tracker that surrounds the LHCb interaction region. The VELO is moving from silicon strip technology to hybrid pixel sensors, where silicon sensors are bonded to VeloPix ASICs. Sensor prototypes have undergone rigorous testing using the Timepix3 Telescope at the SPS, CERN. The main components of the upgrade are summarised and testbeam results presented.

  19. 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.

  20. The LHCb Trigger and its Performance in 2011

    CERN Document Server

    Aaij, R; Alessio, F; Amato, S; Aslanides, E; Belyaev, I; van Beuzekom, M; Bonaccorsi, E; Bonnefoy, R; Brarda, L; Callot, O; Cattaneo, M; Chanal, H; Chebbi, M; Cid Vidal, X; Clemencic, M; Closier, J; Coco, V; Cogan, J; Deschamps, O; Dijkstra, H; Drancourt, C; Dzhelyadin, R; Frank, M; Gandelman, M; Gaspar, C; Gligorov, V V; Göbel, C; Granado Cardoso, L A; Guz, Yu; Haen, C; He, J; van Herwijnen, E; Hulsbergen, W; Jacobsson, R; Jost, B; Karbach, T M; Kerzel, U; Koppenburg, P; Krocker, G; Langenbruch, C; Lax, I; Le Gac, R; Lefèvre, R; Lefrançois, J; Leroy, O; Li Gioi, L; Liu, G; Machefert, F; Machikhiliyan, I V; Magne, M; Mancinelli, G; Marconi, U; Martín Sánchez, A; Minard, M-N; Monteil, S; Neufeld, N; Niess, V; Oggero, S; Pérez-Calero Yzquierdo, A; Perret, P; Perrin-Terrin, M; Pietrzyk, B; Puig Navarro, A; Raven, G; Robbe, P; Ruiz, H; Schune, M-H; Schwemmer, R; Serrano, J; Shapoval, I; Skwarnicki, T; Souza De Paula, B; Spradlin, P; Stahl, S; Subbiah, V K; T’Jampens, S; Teubert, F; Thomas, C; Vesterinen, M; Williams, M; Witek, M; Zvyagin, A

    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 11MHz 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.

  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 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...

  3. Novel real-time alignment and calibration of the LHCb detector and its performance

    Science.gov (United States)

    Borghi, S.

    2017-02-01

    The LHCb detector is a forward spectrometer at the LHC, designed to perform high precision studies of B and D hadrons. In Run II of the LHC, a new scheme for the software trigger at LHCb allows splitting the triggering of events in two stages, giving room to perform the detector 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 constants, 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 us 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.

  4. B meson proper time measurements with the LHCb experiment impact on physics parameters and calibration methods

    CERN Document Server

    Balbi, G

    2007-01-01

    The LHCb (Large Hadron Collider beauty) experiment is one of the four experiments at the LHC, and is specifically dedicated to explore the B-meson dynamics. To this end, LHCb will exploit the large beauty production cross section, expected to be about 500 µb at 14 TeV p-p collisions. Differently from the B-factory case, the hadronization of the b-quarks at LHC will generate all the possible B-hadrons, remarkably the Bs and Bc mesons, where the present experimental knowledge is still rather poor. The number of b/b_bar pairs produced at the LHCb interaction point will be of the order of 10^12 per year, allowing for the search of extremely rare decays, with branching fractions at the level of 10^-9. In order to reduce the acquisition rate to a sustainable level (order of 2 kHz), maintaining at the same time a high efficiency on the signals of interest, LHCb is provided with an efficient and flexible trigger system. LHCb, by means of its vertex detector, will be able to reconstruct the proper time of decays wi...

  5. 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.

  6. Collision Rate Monitors for LHC

    CERN Document Server

    Bravin, E; Burger, S; Byrd, J M; Chow, K; Dutriat, C; Jolliot, M; Lefèvre, T; Matis, H S; Monroy, M; Talanov, V; Turner, W C; Ratti, A; Renet, S

    2007-01-01

    Collision rate monitors are essential in bringing particle beams into collision and optimizing the performances of a collider. In the case of LHC the relative luminosity will be monitored by measuring the flux of small angle neutral particles produced in the collisions. Due to the very different luminosity levels at the four interaction regions (IR) of LHC two different types of monitors have been developed. At the high luminosity IR (ATLAS and CMS) fast ionization chambers will be installed while at the other two (ALICE and LHC-b) solid state polycrystalline Cadmium Telluride (CdTe) detectors will be used. The ionization chambers are being developed by LBNL while the CdTe monitors are being developed by CERN and CEA-LETI.

  7. A study of $B \\to K\\pi$ decays with the LHCb experiment

    CERN Document Server

    Buckley, A; Gibson, V

    2005-01-01

    LHCb is a b-physics detector experiment which will take data at the 14 TeV LHC accelerator at CERN from 2007 onward. In this thesis I present two main areas of work relating to LHCb; firstly an investigation of a novel pattern recognition method in the LHCb RICH detectors and secondly a study of LHCb's potential to reconstruct and identify B -> K pi decays. The pattern recognition studies presented here make use of a Markov Chain sampler to identify Cerenkov rings on a detector pixel array. The method presented does not use the tracking information required by the standard LHCb particle identification system. Studies have been performed to characterise the performance of the trackless ring-finder in the RICH2 detector and to investigate the sources of untracked rings. The ring-finder performance is seen to seriously degrade in high-occupancy regions, indicating that tracking information is required for realistic particle ID in LHCb. The sampler has also been integrated into the RICH2 background-estimation sys...

  8. 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.

  9. The LHCb Data Management System

    CERN Document Server

    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.

  10. Searches for exotica at LHCb

    CERN Document Server

    Vazquez Gomez, Ricardo

    2014-01-01

    Direct and indirect searches for the existence of particles beyond the Standard Model can be performed at the LHCb detector exploiting its unique forward acceptance, high vertex and momentum resolution, and excellent particle identification. In these proceedings, the latest results obtained with the LHCb detector are presented, focusing on rare $\\tau$ and $B$ decays and on decays involving $b\\overline{b}$ pairs in the final state.

  11. LHCb results on multi-parton interactions, soft QCD and diffraction

    CERN Document Server

    Kucharczyk, Marcin

    2016-01-01

    Due to its unique pseudorapidity coverage ($2 < \\eta < 5$) and excellent performance, the LHCb detector allows for studying soft QCD processes at large rapidities and low transverse momenta. Selected results, such as charged particle multiplicities and densities, forward energy flow and prompt charm production are briefly summarized in these proceedings. The measurements are performed using large samples of proton–proton collision data accumulated with the LHCb detector at $\\sqrt s = 7~ \\text {TeV}$. The results are compared with predictions from a number of different Monte Carlo event generators providing a unique insight into particle production in the forward region at the LHC.

  12. Test of the photon detection system for the LHCb RICH Upgrade in a charged particle beam

    CERN Document Server

    Baszczyk, Mateusz Karol; Calabrese, Roberto; Cardinale, Roberta; Carniti, Paolo; Cassina, Lorenzo; Cavallero, Giovanni; Cojocariu, Lucian Nicolae; Cotta Ramusino, Angelo; D'Ambrosio, Carmelo; Dorosz, Piotr Andrzej; Easo, Sajan; Eisenhardt, Stephan; Fiorini, Massimiliano; Frei, Christoph; Gambetta, Silvia; Gibson, Valerie; Gotti, Claudio; Harnew, Neville; He, Jibo; Keizer, Floris; Kucewicz, Wojciech; Maciuc, Florin; Maino, Matteo; Malaguti, Roberto; Matteuzzi, Clara; Mccann, Michael Andrew; Morris, Adam; Muheim, Franz; Papanestis, Antonis; Pessina, Gianluigi; Petrolini, Alessandro; Piedigrossi, Didier; Pistone, Alessandro; Placinta, Vlad-Mihai; Sigurdsson, Saevar; Simi, Gabriele; Smith, Jackson William; Spradlin, Patrick; Tomassetti, Luca; Wotton, Stephen

    2016-01-01

    The LHCb detector will be upgraded to use the available luminosity at the LHC in Run III and extend its potential for discovery. The Ring Imaging Cherenkov (RICH) detectors are one of the key components of the LHCb detector for particle identification. In this paper, we describe the setup and the results of the first tests in a particle beam carried out to assess prototypes of the upgraded optoelectronic chain from the Multi-Anode PMT photosensor to the readout and data acquisition system.

  13. More beauty quarks to understand antimatter better Follow LHCb physicist Patrick Koppenburg

    CERN Document Server

    2015-01-01

    Follow Swiss @LHCbExperiment physicist @PKoppenburg from Nikhef National institute for subatomic physics in the Netherlands, as he shares his thoughts about the new physics frontiers opening up when the LHC begins collisions at the higher energy of #13TeV. Each week a new video will be uploaded to https://www.youtube.com/playlist?list... allowing you to follow physicists from @ATLASexperiment @ALICEexperiment @CMSexperiment or @LHCbExperiment as the search the new frontiers in physics. Read more about these new frontiers in physics: http://cern.ch/go/x8VH

  14. Test of the photon detection system for the LHCb RICH Upgrade in a charged particle beam

    CERN Document Server

    Baszczyk, M.K.

    2017-01-01

    The LHCb detector will be upgraded to make more efficient use of the available luminosity at the LHC in Run III and extend its potential for discovery. The Ring Imaging Cherenkov detectors are key components of the LHCb detector for particle identification. In this paper we describe the setup and the results of tests in a charged particle beam, carried out to assess prototypes of the upgraded opto-electronic chain from the Multi-Anode PMT photosensor to the readout and data acquisition system.

  15. Distributed control and monitoring of high-level trigger processes on the LHCb online farm

    CERN Document Server

    Vannerem, P; Jost, B; Neufeld, N

    2003-01-01

    The on-line data taking of the LHCb experiment at the future LHC collider will be controlled by a fully integrated and distributed Experiment Control System (ECS). The ECS will supervise both the detector operation (DCS) and the trigger and data acquisition (DAQ) activities of the experiment. These tasks require a large distributed information management system. The aim of this paper is to show how the control and monitoring of software processes such as trigger algorithms are integrated in the ECS of LHCb.

  16. Electroweak results at LHCb

    Directory of Open Access Journals (Sweden)

    Amhis Yasmine

    2012-06-01

    Full Text Available W and Z production cross-sections have been measured in proton-proton collisions at a center-of-mass energy of 7 TeV using the decays W → μv, Z → μμ and Z → ττ collected by the LHCb detector. For all the measurements at least one of the reconstructed muons has a transverse momentum, pT, above 20 GeV/c and a pseudorapidity, η, between 2 and 4.5. In the case of the Z, a di-muon invariant mass between 60 GeV/c2 and 120 GeV/c2 is required. Theoretical predictions, calculated at next-to-next-to-leading order in QCD using recent parton distribution functions (PDFs, are found to be in agreement with the measurements.

  17. LHCb Tag Collector

    CERN Document Server

    Fuente Fernàndez, P; Cousin, N

    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 software management and Nightly Build programs is possible via a Python API. Data are stored in a relational database with the help of an ORM (Object-Relational Mapping) library.

  18. 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...

  19. 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.

  20. 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.

  1. 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...

  2. 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.

  3. Electroweak physics at LHCb

    CERN Document Server

    Bifani, Simone

    2014-01-01

    Measurements of electroweak boson production provide an important test of the Standard Model at the LHC energies and allow the partonic content of the proton to be constrained. $W$ and $Z$ bosons are reconstructed in several leptonic final states using data samples corresponding to an integrated luminosity of up to about 1 $fb^{-1}$. Inclusive and associated production cross-sections are reported.

  4. Optimization of the Muon Identification software for LHCb Run II

    CERN Document Server

    Albrecht, Johannes; Dungs, Kevin; Lopes, Helder; Martinez Santos, Diego; Prisciandaro, Jessica; Sciascia, Barbara; Syropoulos, Vasileios; Vazquez Gomez, Ricardo

    2017-01-01

    The muon identification code in the LHCb HLT software trigger and offline reconstruction has been revisited in view of the LHC Run 2. This software has undergone a significant refactorisation, resulting in a modularized common code base between the HLT and offline event processing. Because of the later, the muon identification is now identical in HLT and offline. The HLT1 algorithm sequence has been updated given the new rate and timing constraints. Also information from the TT subdetector is used in order to reduce ghost tracks and optimize for low pT muons. The current software is presented here together with performances studies showing improved efficiencies and timing.

  5. LHCb Upgraded RICH 2 Engineering Design Review Report

    CERN Document Server

    Garsed, Philip John; Cardinale, Roberta; Petrolini, Alessandro; Benettoni, Massimo; Simi, Gabriele; Zago, M; Easo, Sajan; D'Ambrosio, Carmelo; Frei, Christoph; He, Jibo; Piedigrossi, Didier

    2016-01-01

    During the Long Shutdown 2 of the LHC, the LHCb experiment and, specifically, its two Ring Imaging Cherenkov (RICH) detectors will undergo a major upgrade. RICH 2 will be refurbished with new photon detectors and their associated electronics, with the capability of up to 40 MHz sustained acquisition rate. A new support and cooling system has been developed for the two photodetector arrays, retaining the vessel, gas and optical systems unchanged. This document describes their new mechanical arrangement, its engineering design, installation and alignment. A summary of the project schedule and Institute responsibilities is provided.

  6. System Test of a Prototype LHCb RICH Detector

    CERN Document Server

    Patel, M

    2004-01-01

    A prototype of the LHCb Ring Imaging Cherenkov detector has been constructed. The prototype module contained a pre-production Pixel Hybrid Photon Detector, mounted on the final photon detector mechanics. The photon detector was read out at the full LHC speed of 40 MHz using the full prototype on-detector RICH electronics readout chain. The readout uses radiation-tolerant FPGA technology, 1.6 GHz optical links and 40 MHz trigger-timing and control (TTC). The photon detector was mounted in a gas vessel and Cherenkov rings have been observed from and N$_2$ radiator using electron and pion beams.

  7. Flavour tagging of $b$ mesons in $pp$ collisions at LHCb

    CERN Multimedia

    Mueller, Vanessa

    2016-01-01

    Flavour tagging, i.e. the inference of the production flavour of reconstructed $b$ hadrons, is essential for precision measurements of decay time-dependent $CP$ violation and of mixing parameters in the the neutral $B$ meson systems. LHC's $pp$ collisions with their high track multiplicities constitute a challenging environment for flavour tagging and demand for new and improved strategies. We present recent progress and new developments in flavour tagging at the LHCb experiment, which will allow for a further improvement of $CP$ violation measurements in decays of $B^0$ and $B_s^0$ mesons.

  8. LHCb Upgraded RICH 1 Engineering Design Review Report

    CERN Document Server

    Adinolfi, Marco; Petridis, Konstantinos; Rademacker, Jonas; Garsed, Philip John; Wotton, Stephen; Cardinale, Roberta; Petrolini, Alessandro; Clark, David Edward; Egede, Ulrik; Mccann, Michael Andrew; Patel, Mitesh; Savidge, Trevor Edward; Websdale, David; Brock, Matthew; Harnew, Neville; Tacon, M; Benettoni, Massimo; Brummitt, Amanda Jayne; Easo, Sajan; Papanestis, Antonis; Ricciardi, Stefania; Wilson, Fergus; D'ambrosio, Carmelo; Frei, Christoph; He, jibo; Piedigrossi, Didier

    2016-01-01

    During the Long Shutdown 2 of the LHC, the LHCb collaboration will replace the upstream Ring Imaging Cherenkov detector (RICH 1). The magnetic shield of the current RICH 1 will be modified, new spherical and plane mirrors will be installed and a new gas enclosure will be manufactured. New photon detectors (multianode photomultiplier tubes) will be used and these, together with their readout electronics, require a new mechanical support system. This document describes the new optical arrangement of RICH 1, its engineering design, installation and alignment. A summary of the project schedule and institute responsibilities is provided.

  9. 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...

  10. LHCb: Beam and Background Monitoring and the Upgrade of the Timing and Fast Control System of the LHCb experiment at CERN

    CERN Document Server

    Alessio, F

    2009-01-01

    The LHCb experiment at CERN is preparing for first real data taking, foreseen by the end of the year 2009 with the start-up of the LHC. A large amount of work of commissioning, tests and improvements of the full detector has been done in order to optimize its performance. During my first year as a Doctoral Student at CERN, I have been working on the timing and readout control of the LHCb experiment in the frame of the LHCb Online group. The group is responsible for the full data acquisition of the LHCb experiment, from the Front-End Electronics (FEE) to the storage of the data for offline analysis, as well as the Timing and Fast Control (TFC) system. The latter controls and distributes centrally timing and trigger information, as well as synchronous and asynchronous commands to the readout system. It is also responsible for receiving and adjusting the bunch and orbit clocks of the LHC machine and distributing it to the electronics of the whole experiment. It is of vital importance to assure that the timing o...

  11. Absence of the Lhcb1 and Lhcb2 proteins of the light-harvesting complex of photosystem II - effects on photosynthesis, grana stacking and fitness.

    Science.gov (United States)

    Andersson, Jenny; Wentworth, Mark; Walters, Robin G; Howard, Caroline A; Ruban, Alexander V; Horton, Peter; Jansson, Stefan

    2003-08-01

    We have constructed Arabidopsis thaliana plants that are virtually devoid of the major light-harvesting complex, LHC II. This was accomplished by introducing the Lhcb2.1 coding region in the antisense orientation into the genome by Agrobacterium-mediated transformation. Lhcb1 and Lhcb2 were absent, while Lhcb3, a protein present in LHC II associated with photosystem (PS) II, was retained. Plants had a pale green appearance and showed reduced chlorophyll content and an elevated chlorophyll a/b ratio. The content of PS II reaction centres was unchanged on a leaf area basis, but there was evidence for increases in the relative levels of other light harvesting proteins, notably CP26, associated with PS II, and Lhca4, associated with PS I. Electron microscopy showed the presence of grana. Photosynthetic rates at saturating irradiance were the same in wild-type and antisense plants, but there was a 10-15% reduction in quantum yield that reflected the decrease in light absorption by the leaf. The antisense plants were not able to perform state transitions, and their capacity for non-photochemical quenching was reduced. There was no difference in growth between wild-type and antisense plants under controlled climate conditions, but the antisense plants performed worse compared to the wild type in the field, with decreases in seed production of up to 70%.

  12. Supervision de l'écriture de données de l'expérience LHCb

    CERN Document Server

    Fanane, C

    2008-01-01

    Located on the French-Swiss border near Geneva, CERN is one of the world's biggest scientific laboratories in particles physics, home for both theoretical and experimental research. At CERN the world's most powerful particle collider was build and is now being commissioned, the Large Hadron Collider (LHC). The LHC, designed as a ring collider, is hosting several big physics experiments,including the Large Hadron Collider beauty experiment (LHCb). The LHC, together with the LHCb experiment are expected to go officially into operation in the middle of September 2008. It is precisely in this commissioning phase of the LHCb detector that my internship between April and September 2008 takes place. The aim of my project is to implement a monitoring system for the event data writing of physics data coming from the LHCb DAQ System. Event data writing is the last stage of the LHCb DAQ System and is a crucial part for the success of the experiment. It is a fully redundant distributed system composed of various tasks an...

  13. Start of run2 physics at the Large Hadron Collider (LHC)

    CERN Multimedia

    Brice, Maximilien

    2015-01-01

    Images from the CERN Control Centre (CCC), where operators control the LHC, and from the control rooms of the ALICE, ATLAS, CMS and LHCb experiments, where operators control huge detectors that capture data from collisions between beams of protons in the LHC.

  14. Processing LHC data

    CERN Multimedia

    CERN IT department

    2013-01-01

    The LHC produces 600 million collisions every second in each detector, which generates approximately one petabyte of data per second. None of today’s computing systems are capable of recording such rates. Hence sophisticated selection systems are used for a first fast electronic pre-selection, only passing one out of 10 000 events. Tens of thousands of processor cores then select 1% of the remaining events. Even after such a drastic data reduction, the four big experiments, ALICE, ATLAS, CMS and LHCb, together need to store over 25 petabytes per year. The LHC data are aggregated in the CERN Data Centre, where initial data reconstruction is performed, and a copy is archived to long-term tape storage. Another copy is sent to several large scale data centres around the world. Subsequently hundreds of thousands of computers from around the world come into action: harnessed in a distributed computing service, they form the Worldwide LHC Computing Grid (WLCG), which provides the resources to store, distribute, an...

  15. 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.

  16. Imaging the LHC beams with silicon and scintillating fibre vertex detectors

    Science.gov (United States)

    Rihl, M.

    2017-02-01

    The LHCb Vertex Locator (VELO) is used to reconstruct beam-gas interaction vertices which allows one to obtain precise profiles of the LHC beams. In LHCb, this information is combined with the profile of the reconstructed beam-beam collisions and with the LHC beam currents to perform precise measurements of the luminosity. This beam-gas imaging (BGI) method also allows one to study the transverse beam shapes, beam positions and angles in real time. Therefore, a demonstrator beam-gas vertex detector (BGV) based on scintillating fibre modules has been built and installed in LHC Ring 2 at point 4.

  17. Imaging the LHC beams with silicon and scintillating fibre vertex detectors

    CERN Document Server

    Rihl, M

    2016-01-01

    The LHCb Vertex Locator (VELO) is used to reconstruct beam–gas interaction vertices which allows one to obtain precise profiles of the LHC beams. In LHCb, this information is combined with the profile of the reconstructed beam–beam collisions and with the LHC beam currents to perform precise measurements of the luminosity. This beam–gas imaging (BGI) method also allows one to study the transverse beam shapes, beam positions and angles in real time. Therefore, a demonstrator beam–gas vertex detector (BGV) based on scintillating fibre modules has been built and installed in LHC Ring 2 at point 4.

  18. Imaging the LHC beams with silicon and scintillating fibre vertex detectors

    CERN Document Server

    Rihl, M

    2016-01-01

    The LHCb Vertex Locator (VELO) is used to reconstruct beam–gas interaction vertices which allows one to obtain precise profiles of the LHC beams. In LHCb, this information is combined with the profile of the reconstructed beam–beam collisions and with the LHC beam currents to perform precise measurements of the luminosity. This beam–gas imaging (BGI) method also allows one to study the transverse beam shapes, beam positions and angles in real time. Therefore, a demonstrator beam–gas vertex detector (BGV) based on scintillating fibre modules has been built and installed in LHC Ring 2 at point 4.

  19. Production measurements at LHCb

    CERN Document Server

    Rachwal, Bartlomiej

    2017-01-01

    The $\\text{LHC}b$ detector, with its excellent momentum resolution and flexible trigger strategy, is ideally suited for measuring heavy quark and quarkonia production properties. In addition, the new system of forward shower counters installed upstream and downstream has begun to be used, therefore the experiment is being suited to measure central exclusive production. The $\\text{LHC}b$ measurements of inclusive and differential cross-sections of the production of $\\text{J}/\\psi$ resonance and $\\text{J}/\\psi$ pairs, as well bottom quarks and $\\text{Z}^0$ boson, based on Run 2 datasets are summarized. Finally, results on the prompt production of open charm hadrons and the exclusive production of charmonium are discussed.

  20. LHCb Computing Resource usage in 2015 (II)

    CERN Document Server

    Bozzi, Concezio

    2016-01-01

    This documents reports the usage of computing resources by the LHCb collaboration during the period January 1st – December 31st 2015. The data in the following sections has 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. Open Access to the LHC takes on a new meaning

    CERN Multimedia

    2008-01-01

    Complete scientific documentation on the LHC machine and detectors is now freely available on the Web. The ATLAS collaboration, shown here, contributed to the 1,600-page scientific documentation of the LHC, along with staff from the other five detectors and the LHC machine.Now that the LHC tunnel and the experimental caverns are shut down for public visits, "Open Access to the LHC" has taken on an entirely new meaning. Last Thursday, 14 August, seven major articles were published electronically in a special issue of the Journal of Instrumentation (JINST). Together they form the complete scientific documentation on the design and construction of the LHC machine and the six detectors (ALICE, ATLAS, CMS, LHCb, LHCf and TOTEM), and thus on the entire LHC project, well before start-up on 10 September. For many years to come, these papers will serve as key references for the stream of scientific results that will begin to emerge from the ...

  2. 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...

  3. Development of ring imaging Cherenkov detectors for the LHCb experiment

    CERN Document Server

    John, M J J

    2001-01-01

    This thesis reports on work done as part of the development of the Ring Imaging Cherenkov (RICH) detectors of the LHCb experiment. The context of this work is set out in Chapter 1, which includes an overview of the physics of CP violation, followed by a discussion of other experiments that study B physics. LHCb itself is then described, with particular emphasis on its RICH detectors, and the photon detectors to be used therein. The work done by the author to ensure an adequate shielding of the photon detectors in the two RICH detectors from the magnetic fields produced by the LHCb dipole is then presented. A candidate photodetector for the RICH is the Pixel HPD. The author's contribution to the upgrade of the HPD test system to operate at the LHC bunch-crossing rate of 40MHz is the subject of the following section. This system was used to investigate and optimise a method of minimising the threshold distribution of the Pixel HPD's encapsulated readout chip. The final chapter of the thesis concerns the aerogel...

  4. Using Rare Decays to Probe the Standard Model at LHCb

    CERN Document Server

    Sepp, Indrek

    The Large Hadron Collider beauty Experiment (LHCb) detector is one of the four main particle detectors on the Large Hadron Collider (LHC). It is dedicated to the study of physics processes involving b quarks. This thesis presents three analyses of data collected by LHCb. The first measures the photoelectron yield of the Ring Imaging Cherenkov Detector (RICH) detector subsystem, which distinguishes between pions, kaons and protons. The yield is seen to be 15% (19%) less than that in the simulation for the $\\rm C_4 F_{10}$ ($\\rm CF_4$) radiator medium. The result is a Particle Identication (PID) performance which is sufficient for the physics goals of LHCb, albeit slightly less than expected from simulation. No evidence is found for the deterioration of the Hybrid Photon Detector (HPD) quantum efficiency, mirror reflectivity or RICH medium transparency over the course of 2011 and 2012 data collection. The second analysis measures the dependence of the $b \\to \\Lambda^0_b$ to $b \\to B^0$ hadronisation ratio on th...

  5. 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 ...

  6. The LHCb Vertex Locator performance and Vertex Locator upgrade

    CERN Document Server

    INSPIRE-00259789

    2012-01-01

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

  7. Development of Ring Imaging Cherenkov Detectors for LHCb

    CERN Document Server

    Bellunato, T; Matteuzzi, C

    2003-01-01

    The work described in this thesis has been carried out in the framework of the development program of the Ring Imaging Cherenkov (RICH) detectors of the LHCb experiment. LHCb will operate at the Large Hadron Collider at CERN, and it will perform a wide range of measurements in the b-hadrons realm. The extensive study of CP violation and rare decays in the b-hadron system are the main goals of the experiment. An introduction to CP violation in hadronic interactions is given in chapter 1. The high b-b bar production cross section at the LHC energy will provide an unprecedented amount of data which will give LHCb a unique opportunity for precision tests on a large set of physics channels as well as a promising discovery potential for sources of CP violation arising from physics beyond the Standard Model. The experiment is designed in such a way to optimally match the kinematic structure of events where a pair of b quarks is produced in the collision between to 7 GeV protons. Chapter 2 is devoted to an overview o...

  8. The silicon vertex locator for the LHCb upgrade

    CERN Document Server

    Head, Tim

    2014-01-01

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

  9. Tests and Field Map of LHCb Dipole Magnet

    CERN Document Server

    Losasso, Marcello; Flegel, Wilfried; Giudici, Pierre-Ange; Hernando, Jose Angel; Jamet, Olivier; Lindner, Rolf; Renaud, Jean; Teubert, Frederic

    2005-01-01

    The LHCb experiment at the LHC at CERN is aimed to study CP violation and to measure the rare decays of B-mesons with exceptionally high precision. A 4 Tm dipole magnet is required for particle separation and momentum measurements. The 1600 ton warm magnet with sloping poles was installed and fully commissioned by the end of 2004. It is the first detector magnet of the four LHC experiments to have been aligned and commissioned in its final position. In this paper the magnet installation in the underground cavern of Point 8 and its alignment on the beam line are shortly reviewed. Results of a first magnetic field mapping in the region of the magnet poles and the fringe field in the location of the RICH detectors are presented. The mechanical equipment used for the automatic displacement of the Hall probe array is described together with the precision of the measurements obtained which are compared with TOSCA finite element calculations.

  10. Beam test results for the upgraded LHCb RICH opto-electronic readout system

    CERN Multimedia

    Carniti, Paolo

    2016-01-01

    The LHCb experiment is devoted to high-precision measurements of CP violation and search for New Physics by studying the decays of beauty and charmed hadrons produced at the Large Hadron Collider (LHC). Two RICH detectors are currently installed and operating successfully, providing a crucial role in the particle identification system of the LHCb experiment. Starting from 2019, the LHCb experiment will be upgraded to operate at higher luminosity, extending its potential for discovery and study of new phenomena. Both the RICH detectors will be upgraded and the entire opto-electronic system has been redesigned in order to cope with the new specifications, namely higher readout rates, and increased occupancies. The new photodetectors, readout electronics, mechanical assembly and cooling system have reached the final phase of development and their performance was thoroughly and successfully validated during several beam test sessions in 2014 and 2015 at the SPS facility at CERN. Details of the test setup and perf...

  11. The early career, gender, and diversity actions at the LHCb Collaboration

    CERN Multimedia

    Rademacker, Jonas

    2016-01-01

    Numerous surveys of modern particle physics indicate that the discipline is still largely a male pursuit, and one in which women and other marginalised groups continue to face discriminatory practices. The fraction of female particle physicists reduces with each career stage. Early career particle physicists face precarious employment conditions with serial short term contracts, long working hours, the frequent need to relocate, and little prospect for a permanent academic position. There are indications that these employment conditions add to the gender-imbalance in the field, but clearly, this problem directly affects both male and female early career scientists. The LHCb experiment has, as the first (and so far only) LHC experiment, created a dedicated office for Early Career Gender and Diversity (ECGD) (see http://lhcb.web.cern.ch/lhcb/ECGD_Office/ECGD-intro.html ). The ECGD office’s role is to to advise the management on ECGD matters; provide a point of contact for anybody experiencing any kind discrim...

  12. Handling of the Generation of Primary Events in Gauss, the LHCb Simulation Framework

    CERN Multimedia

    Corti, G; Brambach, T; Brook, N H; Gauvin, N; Harrison, K; Harrison, P; He, J; Ilten, P J; Jones, C R; Lieng, M H; Manca, G; Miglioranzi, S; Robbe, P; Vagnoni, V; Whitehead, M; Wishahi, J

    2010-01-01

    The LHCb simulation application, Gauss, consists of two independent phases, the generation of the primary event and the tracking of particles produced in the experimental setup. For the LHCb experimental program it is particularly important to model B meson decays: the EvtGen code developed in CLEO and BaBar has been chosen and customized for non coherent B production as occuring in pp collisions at the LHC. The initial proton-proton collision is provided by a different generator engine, currently Pythia 6 for massive production of signal and generic pp collisions events. Beam gas events, background events originating from proton halo, cosmics and calibration events for different detectors can be generated in addition to pp collisions. Different generator packages are available in the physics community or specifically developed in LHCb, and are used for the different purposes. Running conditions affecting the events generated such as the size of the luminous region, the number of collisions occuring in a bunc...

  13. Improving the gas gain monitoring system in multiwire proportional chambers for MUON detector of LHCb experiment.

    CERN Document Server

    Ruvinskaia, Ekaterina

    2016-01-01

    The gas gain monitoring system in multi-wire proportional chambers for MUON detector of LHCb has been constructed and commissioned. It includes an online- monitoring, tools for analysis the archived data and an alarm system on the quality of the gas mixture. Finally, it will be implemented in the main ECS of LHCb for MUON detector and as a part of safety system of LHCb as a permanent online monitor of the quality of the gas mixture in MWPCs. The main advantage of this setup is a monitoring of Gas Gain (GG) in MWPCs with radioactive sources independently from the presence of beam at LHC. It also provides an option for prompt reaction in case of a problem with the gas.

  14. Highlights of LHCb Measurement in Rare Decays and Discovery of First Pentaquark States with Run 1 Data

    CERN Document Server

    Ukleja, Artur

    2016-01-01

    In pp collisions at the LHC, the LHCb experiment has collected the world’s largest sample of beauty and charmed hadrons. Very precise mea- surements obtained from these data provide tests of the Standard Model, which are indirect searches for new physics. The highlights obtained using data of an integrated luminosity of 3.0 fb

  15. 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...

  16. 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...

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Multiple charm production at the LHC energy

    Energy Technology Data Exchange (ETDEWEB)

    Berezhnoy, A. V., E-mail: Alexander.Berezhnoy@cern.ch [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation); Likhoded, A. K., E-mail: Anatolii.Likhoded@ihep.ru; Luchinsky, A. V., E-mail: Alexey.Luchinsky@ihep.ru; Novoselov, A. A., E-mail: Alexey.Novoselov@cern.ch [Institute for High Energy Physics (Russian Federation)

    2013-01-15

    Cross sections for J/{psi} mesons produced in association with open charm and two charmed hadrons from different cc-bar pairs under LHC conditions are predicted theoretically. The respective processes are considered both in single and in double parton interactions. Particular attention is given to kinematical limits of the LHCb detector, and a comparison with the most recent experimental data is performed for them.

  2. Forward EW Physics at the LHC

    CERN Document Server

    Farry, Stephen

    2016-01-01

    Measurements of electroweak production in the forward region at the LHC provide unique and complementary information to those performed in the central region. Studies have been performed not just by LHCb, a dedicated forward detector, but also by ATLAS and CMS, which are primarily situated in the central region but can exploit forward calorimetry coverage to contribute to the understanding of SM processes in the forward region.

  3. Highlights of LHC experiments – Part I

    CERN Document Server

    Charlton, Dave; The ATLAS collaboration

    2017-01-01

    The superb performance of the LHC accelerator in 2016, in both live time and peak luminosity, has provided a large data sample of collisions at 13 TeV. Excellent performances of the ATLAS and LHCb detectors, together with highly performant offline and analysis systems, mean that a wealth of results are already available from 13 TeV data. Selected highlights are reported here.

  4. SciFi - A large scintillating fibre tracker for LHCb

    Science.gov (United States)

    Kirn, Thomas

    2017-02-01

    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. Concept, design and operational parameters are driven by the challenging LHC environment including significant ionising and neutron radiation levels. Over a total active surface of 360 m2 the SciFi Tracker will use scintillating fibres (∅ = 0.25 mm) read out by state-of-the-art multi-channel Silicon Photomultipliers (SiPMs) arrays. A custom ASIC will be used to digitise the signals from the SiPMs. The project is now at the transition from R&D to series production. We will present the evolution of the design and the latest lab and test beam results.

  5. SciFi - A large Scintillating Fibre Tracker for LHCb

    CERN Multimedia

    Quagliani, Renato

    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 40MHz 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. Concept, design and operational parameters are driven by the challenging LHC environment including significant ionising and neutron radiation levels. Over a total active surface of 360 m2 the SciFi Tracker will use scintillating fibres (Ø 0.25 mm) 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 project is now at the transition from R&D to series production. We will present the evolution of the design a...

  6. 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...

  7. Parton distributions with LHC data

    DEFF Research Database (Denmark)

    Ball, R.D.; Deans, C.S.; Del Debbio, L.;

    2013-01-01

    We present the first determination of parton distributions of the nucleon at NLO and NNLO based on a global data set which includes LHC data: NNPDF2.3. Our data set includes, besides the deep inelastic, Drell-Yan, gauge boson production and jet data already used in previous global PDF determinati......We present the first determination of parton distributions of the nucleon at NLO and NNLO based on a global data set which includes LHC data: NNPDF2.3. Our data set includes, besides the deep inelastic, Drell-Yan, gauge boson production and jet data already used in previous global PDF...... determinations, all the relevant LHC data for which experimental systematic uncertainties are currently available: ATLAS and LHCb W and Z rapidity distributions from the 2010 run, CMS W electron asymmetry data from the 2011 run, and ATLAS inclusive jet cross-sections from the 2010 run. We introduce an improved...... implementation of the FastKernel method which allows us to fit to this extended data set, and also to adopt a more effective minimization methodology. We present the NNPDF2.3 PDF sets, and compare them to the NNPDF2.1 sets to assess the impact of the LHC data. We find that all the LHC data are broadly consistent...

  8. Physics at LHC and beyond

    CERN Document Server

    2014-01-01

    The topics addressed during this Conference are as follows. ---An overview of the legacy results of the LHC experiments with 7 and 8 TeV data on Standard Model physics, Scalar sector and searches for New Physics. ---A discussion of the readiness of the CMS, ATLAS, and LHCb experiments for the forthcoming high-energy run and status of the detector upgrades ---A review of the most up-to-date theory outcome on cross-sections and uncertainties, phenomenology of the scalar sector, constraints and portals for new physics. ---The presentation of the improvements and of the expected sensibilities for the Run 2 of the LHC at 13 TeV and beyond. ---A comparison of the relative scientific merits of the future projects for hadron and e+e- colliders (HL-LHC, HE-LHC, ILC, CLIC, TLEP, VHE-LHC) towards precision measurements of the Scalar boson properties and of the Electroweak-Symmetry-Breaking parameters, and towards direct searches for New Physics.

  9. 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.

  10. Performance of Hybrid Photon Detectors and Studies of Two-Body Hadronic B Decays at LHCb

    CERN Document Server

    Carson, L; Parkes, C

    2009-01-01

    The LHCb experiment at the CERN LHC accelerator will begin physics data taking in late 2009. LHCb aims to discover New Physics processes via precision measurements using heavy flavoured hadrons, such as $B$ and $D$ hadrons. This thesis describes studies relevant to measurements of $B$ decays to hadronic final states at LHCb. The Ring Imaging Cherenkov (RICH) counters of LHCb are crucial to the performance of such measurements. They use arrays of Hybrid Photon Detectors (HPDs) as their photodetection system. Detailed results are presented from the characterisation programme of the entire sample of 557 HPDs that were produced. Their overall performance is found to be outstanding, with only 2.2\\% of HPDs judged to be unusable for the RICHes. The LHCb requirements and the contractual specifications are met and often exceeded in key areas. The measurement of the single photoelectron detection efficiency, $\\eta$, of the HPD anode is described in detail. The efficiency was measured as $\\eta=(87.9\\pm 1.4)\\%$. This va...

  11. Proton structure at the LHC

    CERN Document Server

    Hartland, Nathan

    2014-01-01

    A determination of Parton Distribution Functions (PDFs) from a global fit to a dataset including measurements from the LHC has been performed. The determinations have been carried out according to the NNPDF methodology, leading to a fit minimising parametrisation bias and with an accurate account of PDF uncertainty. In this thesis the importance of QCD measurements at the LHC to PDF extraction are discussed, and we summarise some of the technical difficulties in their inclusion into PDF fits. A number of methods are presented that permit the efficient inclusion of these observables into PDF determinations. Firstly a Bayesian reweighting procedure taking advantage of the Monte Carlo representation of PDF uncertainties in NNPDF sets is discussed, which is demonstrated by a study of the impact of early W production asymmetry measurements from ATLAS, CMS and LHCb upon an earlier PDF set. A package for the fast computation of observables in an automated NLO framework is presented, providing an interface between Mo...

  12. The LHC at the AAAS

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    The American Association for the Advancement of Science held its annual meeting in the Walter E. Washington Convention Center in Washington D.C. last week.   Veteran science writer Tim Radford introduces LHC scientists during a media briefing at the AAAS annual meeting. Left to right: Felicitas Pauss, Tom LeCompte, Yves Schutz and Nick Hadley. As the world’s largest popular science meeting, the AAAS meeting is a major event in the calendar of science journalists.  At this year’s LHC session, CERN’s coordinator for international relations, Felicitas Pauss, opened the discussion, paving the way for Tom LeCompte of ATLAS, Joe Incandela of CMS, Yves Schutz of ALICE and Monica Pepe-Altarelli of LHCb to report on the status of the first year’s analysis from their experiments.    

  13. Rare leptonic and semileptonic $b$-hadron decays and tests of lepton flavour universality at LHCb

    CERN Document Server

    Bifani, Simone

    2016-01-01

    Rare decays of heavy-flavoured particles provide an ideal laboratory to look for deviations from the Standard Model, and explore energy regimes beyond the LHC reach. Decays proceeding via electroweak penguin diagrams are excellent probes to search for New Physics, and $b \\to s \\ell^+ \\ell^-$ processes are particularly interesting since they give access to many observables such as branching fractions, asymmetries and angular observables. Recent results from the LHCb experiment are reviewed.

  14. Weak boson production from D0 and LHCb in the NNPDF global analysis

    CERN Document Server

    Rojo, Juan

    2016-01-01

    High-precision electroweak production measurements from the Tevatron and the LHC provide important constraints on the quark flavor separation in global PDF fits. In this contribution, we study the impact of the recent D0 W asymmetry measurements and of the LHCb W and Z Run I combination in the global NNPDF analysis. We find that these measurements can be described by NLO QCD theory and that they lead to a significant reduction of PDF uncertainties.

  15. $B_{s}^{0} \\rightarrow D_{s}^{+(*)} D_{s}^{-(*)}$ decays in LHCb

    CERN Multimedia

    Pritchard, A

    2014-01-01

    The decay of a $B_{s}^{0}$ meson to two oppositely charged $D_{s}$ mesons is one that is postulated to be almost exclusively CP even. Measuring the properties of this decay can therefore give important information about the behaviour of the $B_{s}^{0}$ system. This poster presents two of these measurements, made by LHCb, using data from run 1 of the LHC.

  16. 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 ...

  17. Hybrid photon detectors for the LHCb RICH

    CERN Document Server

    Eisenhardt, Stephan

    2006-01-01

    The LHCb Ring Imaging Cherenkov (RICH) counters use the pixel Hybrid Photon Detector (HPD) as a photo-sensitive device. Photo-electrons are produced in semi-transparent multi-alkali photo-cathode (S20) and are accelerated by a voltage of 20 kV onto a pixelated silicon anode. The anode is bump-bonded to the LHCBPIX1 pixel readout chip which amplifies and digitises the anode signals at the LHC speed of 40 MHz. Using a demagnification of five, the effective pixel size at the HPD window is 2.5 x 2.5 mm$^2$. Over the course of 18 months, 550 HPSs will undergo a quality-assurance programme to verify the specifications and to characterise the tubes. The tested parameters include the threshold and noise behaviour of the chip, the response to light emitting diode (LED) light, the demagnification of the electron optics, the leakage current and the depletion of the silicon sensor, the quality of the vacuum, the signal efficiency and the dark count rate. Results of tests of the first nine HPDs of the final design are pr...

  18. 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.

  19. Exotic meson studies at LHCb

    CERN Document Server

    Kreps, Michal

    2014-01-01

    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 $\\psi (2S ) \\gamma$ final state, as well as confirmation the $Z(4430)^+$ state.

  20. Photomultipliers on an LHCb calorimeter

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    An engineer attaches photomultiplier tubes to the electromagnetic calorimeter on the LHCb experiment. These large wall detectors will be used to study the bottom quark, a heavy, short-lived version of quarks found in protons and neutrons. The electromagnetic calorimeter will be used to detect photons, electrons and positrons produced by the decay of these short-lived quarks.

  1. Open charm spectroscopy at LHCb

    CERN Document Server

    Whitehead, Mark

    2015-01-01

    Recent charm spectroscopy results from Dalitz plot analyses of $B$ decays to open charm final states at LHCb are presented. The decay modes used are $B^{+} \\to D^{-} K^{+} \\pi^{+}$, $B^{0} \\to \\overline{D}{}^{0} \\pi^{+} \\pi^{-}$ and $B^{0} \\to \\overline{D}{}^{0} K^{+} \\pi^{-}$.

  2. Charmonia and beauty production measurements with J/psi events at LHCb

    CERN Multimedia

    Sabatino, G

    2009-01-01

    We report on the possibilities of measuring charmonia and beauty productions with the LHCb experiment. Using reconstructed $J/psi$ decays to $/mu^+mu^-$, both the prompt $J/psi$ and the $b-)J/psi$ production cross sections in p-p collisions at LHC energies will be determined in the $J/psi$ eta range 2-5. Due to the very large statistics, this analysis will be possible very early after the LHC start. Other charmonia related measurements will also be discussed, such as that of the $J/psi$ polarization at production or of the production of some of the new X, Y and Z states.

  3. $B^{0}_{s} \\to J \\psi \\eta$ decays and sensitivity to the $B^{0}_{s}$ mixing phase at LHCb

    CERN Document Server

    Carron, B

    2005-01-01

    The LHCb experiment will be installed in the proton-proton Large Hadron Collider (LHC) at CERN, Geneva. The detector is a single arm spectrometer currently under construction: LHC running and LHCb data taking will start in 2007. LHCb will then benefit from the prolific source of B-mesons provided by the LHC. The main goals of the LHCb experiment are to measure the CP asymmetries in the B-meson sector and to study rare decays of b-hadrons. These will extend the measurements presently made with B_d mesons by the Belle (Japan) and BABAR (USA) experiments. The expected accuracy on the comprehensive measurements with both B_d and B s mesons will allow to open new windows on physics beyond the Standard Model. The Standard Model of particle physics (SM) provides the framework for the description of a possible violation of the CP symmetry in the neutral B-meson sector. In particular, it predicts an asymmetry due to CP violation in the time dependent rates for B_{d,s} and B_{d,s}- bar to a common CP eigenstate when th...

  4. LHC Report: The beam is back at the LHC

    CERN Document Server

    Reyes Alemany

    2015-01-01

    A series of sector beam tests paved the way for the start-up of the LHC in 2008 and 2009. These tests and the follow-up of the issues that arose were part of the process that led to a smooth start-up with beam.   Given this experience, sector tests were scheduled to take place several weeks before the 2015 start-up. On the weekend of 6-9 March, beam from the SPS was injected into both LHC injection regions, followed by a first pass through the downstream LHC sectors. For the clockwise LHC beam (called “beam 1”) this meant passing through ALICE and into Sector 2-3, while the anticlockwise beam (called “beam 2”) was threaded through LHCb and all the way from Point 8 to Point 6, where it was extracted by the beam dump kickers onto the beam dump block. The dry runs in the previous weeks were mainly targeted at preparation for the sector tests. The systems tested included: injection, timing, synchronisation and beam instrumentation. The beam interlock ...

  5. $B_{d} \\to K^{*0}\\mu^{+}\\mu^{-}$ as a lab for discovering new physics at LHCb

    CERN Document Server

    Skottowe, Hugh

    2010-01-01

    The analysis of the penguin decay Bd->K*MuMu at LHCb can act as a laboratory for the discovery and understanding of new physics. Through the Operator Product Expansion, the decay kinematics are well understood in both the Standard Model and in a large range of new physics scenarios. The theoretical errors from QCD effects can be characterized and a set of observables have been derived which minimise their influence in measurements. We will describe how these measurements can be made in LHCb with special emphasis on what can be done with a first run of the LHC with a few hundred pb-1 of integrated luminosity.

  6. 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.

  7. 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.

  8. 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 ...

  9. 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 ...

  10. 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.

  11. 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.

  12. LHCb: $\\Upsilon$ and double $J/\\psi$ production at LHCb

    CERN Multimedia

    Frosini, M

    2011-01-01

    The measurement of the $\\Upsilon(1S)$ production cross-section with the LHCb detector is presented, as a function of the $\\Upsilon(1S)$ transverse momentum and rapidity. First observation of double $J/\\psi$ production is also reported together with a first measurement of the cross-section. Prospects for measurements of the $\\chi_c$ and $\\psi(2S)$ cross-sections are also shown.

  13. Quarkonium results from LHCb

    CERN Document Server

    Sabatino, Giovanni

    2012-01-01

    The mechanism for the production of quarkonia in hadronic collisions is not yet completely understood. It is well kown that the LO Colour Singlet Model (CSM) leads to predictions of the cross-sections which are in disagreement with the osbervations at High $P_T$. New theoretical approaches have been proposed in recent years. For example, the Non-Relativistic QCD factorisation formalism, in which Colour Octet diagrams are introduced. Another approach consists in extending the computation of the cross-sections in Colour Singlet Model up to the NNLO. In the Colour Evaporation Model (CEM) instead, the probability of forming a specific quarkonium state is assumed to be independent of the color of the $Q\\bar{Q}$ pair. The debate is still open and experimental confirmations from the LHC experiments are needed to determine the reliability of the proposed models. Open charm can be produced in p-p collisions in association to a $J/\\psi$ meson or in association to another open charm hadron. Predictions for the productio...

  14. Exclusive dimuon production with LHCb

    CERN Multimedia

    Shears, Tara

    2011-01-01

    We report on studies of exclusive dimuon production using LHCb experimental data. Exclusively produced muon pairs can be produced by two photon fusion (a QED process ideally suited to obtaining a precise integrated luminosity measure), or through resonances produced by pomeron-photon fusion or double pomeron exchange.We present cross-section measurements for exclusive dimuon production, and the first observations at a proton-proton collider of exclusive J/psi, psi’ and chi_c states, obtained with 37 pb-1 of data at centre of mass energy of 7 TeV. The resolution of the LHCb detectors allow the chic0, chic1 and chic2 states to be separated. We compare our results to theoretical predictions.

  15. Detector Description Framework in LHCb

    CERN Document Server

    Ponce, Sébastien

    2003-01-01

    The Gaudi architecture and framework are designed to provide a common infrastructure and environment for simulation, filtering, reconstruction and analysis applications. In this context, a Detector Description Service was developed in LHCb in order to also provide easy and coherent access to the description of the experimental apparatus. This service centralizes every information about the detector, including geometry, materials, alignment, calibration, structure and controls. From the proof of concept given by the first functional implementation of this service late 2000, the Detector Description Service has grown and has become one of the major components of the LHCb software, shared among all applications, including simulation, reconstruction, analysis and visualization. We describe here the full and functional implementation of the service. We stress the easiness of customization and extension of the detector description by the user, on the seamless integration with condition databases in order to handle ...

  16. Rare beauty decays at LHCb

    CERN Document Server

    INSPIRE-00258140

    2015-01-01

    In this contribution we review the most recent measurements of the LHCb experiment in the field of rare decays of B mesons. In particular the first observation of the $B^0_s \\to µ^+ µ^-$,­ decay, the angular analysis of $B^0_d \\to K*l^+l^-$ decays and the test of lepton universality in $B^+ \\to K^+ l^+ l^-$ decays are presented.

  17. Reconstruction of two-body B decays in LHCb

    CERN Document Server

    AUTHOR|(CDS)2068023

    2007-01-01

    The observed dominance of matter over antimatter in the Universe leads to the hypothesis of the Sakharov conditions for the laws of nature. One of them implies the breaking of the charge-parity (CP) symmetry. The violation of the CP symmetry has been observed in several decays of kaons and B mesons and is incorporated in the Standard Model via the CKM matrix, describing the quark transitions in the charged current weak interactions. The Large Hadron Collider (LHC) provides a copious source of bb quark pairs, offering an excellent facility to study CP violation in the B meson system. The LHC is a powerful pp collider, which will accelerate proton bunches in opposite directions in a ring of 27 km circumference. Protons will collide every 25 ns at a center-of-mass energy of 14 TeV. It is foreseen to start operation in 2008. LHCb, one of the four experiments along the LHC ring, is dedicated to the study of CP violation and rare decays in the B meson system. Since bb pairs are mostly produced in a forward cone alo...

  18. Automatised Data Quality Monitoring of the LHCb Vertex Locator

    CERN Multimedia

    Szumlak, Tomasz

    2016-01-01

    The LHCb Vertex Locator (VELO) is a silicon strip semiconductor detector operating at just 8mm distance to the LHC beams. Its 172,000 strips are read at a frequency of 1 MHz and processed by off-detector FPGAs followed by a PC cluster that reduces the event rate to about 10 kHz. During the second run of the LHC, which lasts from 2015 until 2018, the detector performance will undergo continued change due to radiation damage effects. This necessitates a detailed monitoring of the data quality to avoid adverse effects on the physics analysis performance. The VELO monitoring infrastructure has been re-designed compared to the first run of the LHC when it was based on manual checks. The new system is based around an automatic analysis framework, which monitors the performance of new data as well as long-term trends and flags issues whenever they arise. An unbiased subset of the detector data are processed about once per hour by monitoring algorithms. The new analysis framework then analyses the plots that are prod...

  19. Reconstruction of two-body B decays in LHCb

    CERN Document Server

    AUTHOR|(CDS)2068023

    2007-01-01

    The observed dominance of matter over antimatter in the Universe leads to the hypothesis of the Sakharov conditions for the laws of nature. One of them implies the breaking of the charge-parity (CP) symmetry. The violation of the CP symmetry has been observed in several decays of kaons and B mesons and is incorporated in the Standard Model via the CKM matrix, describing the quark transitions in the charged current weak interactions. The Large Hadron Collider (LHC) provides a copious source of bb quark pairs, offering an excellent facility to study CP violation in the B meson system. The LHC is a powerful pp collider, which will accelerate proton bunches in opposite directions in a ring of 27 km circumference. Protons will collide every 25 ns at a center-of-mass energy of 14 TeV. It is foreseen to start operation in 2008. LHCb, one of the four experiments along the LHC ring, is dedicated to the study of CP violation and rare decays in the B meson system. Since bb pairs are mostly produced in a forward cone alo...

  20. Latest CERN-LHC HD footage

    CERN Multimedia

    CERN video productions; Daniel Dominguez

    2012-01-01

    Dopesheet Lastest CERN-LHC footage short version 00:00:00:00 to 00:02:03:16 LHC tunnel 00:02:03:16 to 00:02:24:14 Radio frequency cavities 00:02:24:14 to 00:03:32:22 ATLAS cavern and detector 00:03:32:22 to 00:04:24:22 CMS cavern and detector 00:04:24:22 to 00:04:58:16 ALICE cavern and detector 00:04:58:16 to 00:05:52:16 LHCb cavern and detector 00:05:52:16 to 00:07:05:02 Computing centre 00:07:05:03 to 00:07:56:05 Higgs animation 00:07:56:06 to end LHC dipole animation with beams

  1. A Cherenkov-based Beam Loss Scintillator system for beam, background and online luminosity monitoring at the LHCb experiment at CERN

    CERN Document Server

    Alessio, F; Jacobsson, R

    2013-01-01

    The installation of a scintillator-based system in the LHCb cavern was initially proposed in order to observe injection problems around the LHCb interaction region. Thanks to the fact that LHCb had already developed a custom-made electronics board (BPIM) for the LHCb beam pickups and global LHCb timing monitoring, a complete, inexpensive but flexible and robust system was quickly developed and installed few cm from the beam pipe just in front of the LHCb VELO detector in time for the very first beams injected in the LHC. The current and final system – commonly referred to as Beam Loss Scintillator (BLS) system - ultimately played a central role in the fast beam, background and online luminosity monitoring at LHCb. In this paper, the features of the detector – based on quartz radiator and Cherenkov light - are described, including the functionalities that the system acquired during the proton-proton physics programmes in 2009- 2013 thanks to its flexibility, reliability and sensitivity to beam hal...

  2. Studies of the Machine Induced Background, simulations for the design of the Beam Condition Monitor and implementation of the Inclusive $\\phi$ Trigger at the LHCb experiment at CERN

    CERN Document Server

    Lieng, Magnus

    2011-01-01

    LHCb is one of the four major experiments of the LHC at CERN, built to perform precision measurements of CP violation and rare decays. In order to protect the sensitive elements of the experiment from adverse beam conditions the Beam Condition Monitor has been created. Such conditions increase the particle flux arriving from the LHC, known as Machine Induced Background. These particles interfere with the experiment, for example through the physics trigger. In this thesis software development and simulations for the design and validation of the Beam Condition Monitor is shown, ranging from LHCb-specific algorithm implementation to beam dump threshold determination. Furthermore, software development in order to attain a complete simulation chain of machine induced background is shown. The results of these simulations are compared to early data collected at LHCb. Lastly, the development and implementation of the Inclusive $\\phi$ trigger line for the High Level Trigger is presented. This line aims to reconstruct ...

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

    CERN Document Server

    De Capua, S

    2013-01-01

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

  4. New Observations of beauty baryon decays at LHCb

    CERN Document Server

    Vitaly, Andreev

    2014-01-01

    This report describes the work I have done during my summer student association with the LHCb (Large Hadron Collider Beauty Experiment) collaboration at CERN from 30.06 till 26.09.2014. The project was performed in a team with two other summer students. In this report I concentrate on my contribution to the team work. In addition, one section is dedicated to the management framework called “scrum” which we used to collaborate as a team. The goal of my task was to analyze yet unobserved decays of the beauty Lambda-b-0 baryon. This is interesting since the CP violation still remains unobserved in baryons and beauty baryons are generally not well-known yet. LHCb is the first detector where these heavy baryons can be analyzed in detail. In addition these decays may play an important role in other processes and one can gain new insights into the strong interaction. The analysis presented here was performed on the full 2011-2012 LHC run data and includes several decays which are observed for the first time.

  5. Instruments for calibration and monitoring of the LHCb Muon Detector

    CERN Document Server

    Deplano, C; Lai, A

    2006-01-01

    The subject of this Ph. D. thesis is the study and the development of the instruments needed to monitor and calibrate the Muon Detector of the LHCb (Large Hadron Collider beauty) experiment. LHCb is currently under installation at the CERN Large Hadron Collider (LHC) and will start to take data during 2007. The experiment will study B mesons decays to achieve a profound understanding of favour physics in the Standard Model framework and to search signs of new physics beyond. Muons can be found in the final states of many B-decays which are sensitive to CP violation. The Muon Detector has the crucial role to identify the muon particles generated by the b-hadron decays through a measurement of their transverse momentum, already at the first trigger level (Level-0). A 95% effciency in events selection is required for the Muon Trigger, which operates at the Level-0. 1380 detectors are used to equip the whole Muon System and the corresponding 122,112 readout channels must be time aligned and monitored with a resol...

  6. The LHCb Data Acquisition and High Level Trigger Processing Architecture

    Science.gov (United States)

    Frank, M.; Gaspar, C.; Jost, B.; Neufeld, N.

    2015-12-01

    The LHCb experiment at the LHC accelerator at CERN collects collisions of particle bunches at 40 MHz. After a first level of hardware trigger with an output rate of 1 MHz, the physically interesting collisions are selected by running dedicated trigger algorithms in the High Level Trigger (HLT) computing farm. This farm consists of up to roughly 25000 CPU cores in roughly 1750 physical nodes each equipped with up to 4 TB local storage space. This work describes the LHCb online system with an emphasis on the developments implemented during the current long shutdown (LS1). We will elaborate the architecture to treble the available CPU power of the HLT farm and the technicalities to determine and verify precise calibration and alignment constants which are fed to the HLT event selection procedure. We will describe how the constants are fed into a two stage HLT event selection facility using extensively the local disk buffering capabilities on the worker nodes. With the installed disk buffers, the CPU resources can be used during periods of up to ten days without beams. These periods in the past accounted to more than 70% of the total time.

  7. Central Exclusive Production of $\\chi$ Mesons at LHCb

    CERN Document Server

    Bjornstad, Pal Marius

    The LHCb experiment is a forward spectrometer at the Large Hadron Collider, covering a range of pseudorapidity $1.9<\\eta<4.9$. It has a very precise vertex detector called the VELO, near the interaction point. The monitoring software for the VELO is discussed in this thesis. In proton-proton interactions, Central Exclusive Production (CEP) is a process where the protons remain intact after the interaction, and an additional simple central system is produced. CEP processes are selected experimentally by requiring that there is no activity in the detector apart from the central system. The installation of additional detectors to increase the sensitivity at small angles from the beam axis is discussed. A geometrical description of the region of the LHC up to $100$~m on each side of the LHCb interaction point is developed. Simulated forward shower counters are added to the model, and the efficiencies of the detectors are measured. The main part of this thesis describes an analysis of CEP of $\\chi_c$ mes...

  8. LHCb Silicon Tracker DAQ and DCS Online Systems

    CERN Document Server

    Esperante-Pereira, D; Büchler, A; Keune, A; Bay, A; Blanc, F; Bettler, M O; Conti, G; Fave, V; Frei, R; Perrin, A; Potterat, C; Schneider, O; Tran, M; Bauer, C; Britsch, M; Hofmann, W; Maciuc, F; Schmelling, M; Voss, H; Straumann, U; Anderson, J; Chiapolini, N; Hangartner, V; Salzmann, S; Steiner, A; Steinkamp, O; Van Tilburg, J; Tobin, M; Vollhardt, A; Adeva, B; Fungueirino Pazos, A; Gallas, A; Pazos-Alvarez, A; Pérez-Trigo, E; Pló Casasús, M; Saborido, J; Vázquez, P; Gong, A; Iavenko, V; Okhrimenko, O; Pugatch, V

    2009-01-01

    The LHCb experiment at the Large Hadron Collider (LHC) at CERN in Geneva Switzerland is specialized on precision measurements of b quark decays. The Silicon Tracker (ST) contributes a crucial part in tracking the particle trajectories and consists of two silicon micro-strip detectors, the Tracker Turicensis upstream of the LHCb magnet and the Inner Tracker downstream. The radiation and the magnetic field represent new challenges for the implementation of a Detector Control System (DCS) and the data acquisition (DAQ). The DAQ has to deal with more than 270K analog readout channels, 2K readout chips and real time DAQ at a rate of 1.1 MHz with data processing at TELL1 level. The TELL1 real time algorithms for clustering thresholds and other computations run on dedicated FPGAs that implement 13K configurable parameters per board, in total 1.17 K parameters for the ST. After data processing the total throughput amounts to about 6.4 Gbytes from an input data rate of around ~337 Gbytes per second. A finite state mac...

  9. LHCb Silicon Tracker DAQ and DCS Online Systems

    CERN Multimedia

    Buechler, A; Rodriguez, P

    2009-01-01

    The LHCb experiment at the Large Hadron Collider (LHC) at CERN in Geneva Switzerland is specialized on precision measurements of b quark decays. The Silicon Tracker (ST) contributes a crucial part in tracking the particle trajectories and consists of two silicon micro-strip detectors, the Tracker Turicensis upstream of the LHCb magnet and the Inner Tracker downstream. The radiation and the magnetic field represent new challenges for the implementation of a Detector Control System (DCS) and the data acquisition (DAQ). The DAQ has to deal with more than 270K analog readout channels, 2K readout chips and real time DAQ at a rate of 1.1 MHz with data processing at TELL1 level. The TELL1 real time algorithms for clustering thresholds and other computations run on dedicated FPGAs that implement 13K configurable parameters per board, in total 1.17 K parameters for the ST. After data processing the total throughput amounts to about 6.4 Gbytes from an input data rate of around ~337 Gbytes per second. A finite state ma...

  10. LHCb is trying to crack the Standard Model

    CERN Multimedia

    2011-01-01

    LHCb will reveal new results tomorrow that will shed more light on the possible CP-violation measurement reported recently by the Tevatron experiments, different from Standard Model predictions. Quantum Diaries blogger for CERN, Pauline Gagnon, explains how.   LHCb, one of the Large Hadron Collider (LHC) experiments, was designed specifically to study charge-parity or CP violation. In simple words, its goal is to explain why more matter than antimatter was produced when the Universe slowly cooled down after the Big Bang, leading to a world predominantly composed of matter. This is quite puzzling since in laboratory experiments we do not measure a preference for the creation of matter over antimatter. Hence the CP-conservation law in physics that states that Nature should not have a preference for matter over antimatter. So why did the Universe evolve this way? One of the best ways to study this phenomenon is with b quarks. Since they are heavy, they can decay (i.e break down into smaller parts) ...

  11. Prompt physics analysis from the trigger candidates at LHCb: strategy and new dedicated "TURBO" and PID calibration streams

    CERN Document Server

    Sciascia, Barbara

    2016-01-01

    During the first long shutdown of the LHC (2013-2014), the LHCb detector remained essentially unchanged, while the trigger system has been completely revised. Upgrades to the LHCb computing infrastructure have allowed for high quality decay information to be calculated by the software trigger, making separate offline event reconstruction unnecessary. The storage space of the triggered candidate is an order of magnitude smaller than the entire raw event that would otherwise need to be persisted. An application has been designed to process the information calculated by the trigger, with the resulting output used to directly perform physics measurements. Reaching the ultimate precision of the LHCb experiment in real time as the data arrive has the power to transform the experimental approach to processing large quantities of data.

  12. Optimisation of LHCb Applications for Multi- and Manycore Job Submission

    CERN Document Server

    Rauschmayr, Nathalie; Graciani Diaz, Ricardo; Charpentier, Philippe

    The Worldwide LHC Computing Grid (WLCG) is the largest Computing Grid and is used by all Large Hadron Collider experiments in order to process their recorded data. It provides approximately 400k cores and storages. Nowadays, most of the resources consist of multi- and manycore processors. Conditions at the Large Hadron Collider experiments will change and much larger workloads and jobs consuming more memory are expected in future. This has lead to a shift of paradigm which focuses on executing jobs as multiprocessor tasks in order to use multi- and manycore processors more efficiently. All experiments at CERN are currently investigating how such computing resources can be used more efficiently in terms of memory requirements and handling of concurrency. Until now, there are still many unsolved issues regarding software, scheduling, CPU accounting, task queues, which need to be solved by grid sites and experiments. This thesis develops a systematic approach to optimise the software of the LHCb experiment fo...

  13. Measurement of the Bs mixing phase at LHCb

    CERN Document Server

    CERN. Geneva

    2014-01-01

    At scales that are not accessible by direct searches at the LHC, precision measurements of CP violating observables in the mixing and decay of B mesons  may reveal new physics through loop corrections. A good candidate for such indirect searches is the measurement of the CP violating phase phi_s which arises in the interference between the amplitudes of Bs meson decaying directly and after oscillation via b->ccs transitions. This talk will cover recent measurements of phi_s from Bs->J/psihh and DsDs decays at LHCb. Additionally, estimates of possible penguin contributions which are assumed to be zero in SM predictions will be discussed.  

  14. Test beam results of LHCb scintillating fibre tracker prototypes

    Energy Technology Data Exchange (ETDEWEB)

    Bachmann, Sebastian; Comerma, Albert; Gerick, David; Hansmann-Menzemer, Stephanie; Kecke, Matthieu; Leverington, Blake; Mazorra de Cos, Jose; Mitzel, Dominik; Neuner, Max; Uwer, Ulrich; Han, Xiaoxue [Physikalisches Institut, Universitaet Heidelberg (Germany); Collaboration: LHCb-Collaboration

    2016-07-01

    During the Long Shutdown 2 of the LHC, the LHCb detector will undergo a major upgrade to meet the challenges of running at a higher luminosity. The current Inner and Outer Tracking system will not be sufficient to deal with the envisaged increased detector occupancy and higher radiation levels and will be replaced by a single tracking detector based on 0.250 mm diameter plastic scintillating fibres. The fibres are wound to multilayer ribbons 2.4 m long and read out by 128 channel silicon photomultiplier arrays. The Scintillating Fibre (SciFi) tracker will cover a total active area of 360 m{sup 2}, arranged in 12 layers. The performances of prototype modules having 6 and 8 layers of fibre have been tested at the SPS at CERN. This talk focuses on basic properties of the prototype modules such as spatial resolution, single hit efficiency and light yield measured during the test beam campaigns in 2015.

  15. Commissioning and Performance of the LHCb Silicon Tracker

    CERN Multimedia

    van Tilburg, J; Buechler, A; Bursche , A; Chiapolini, N; Elsaesser, C; Hangartner, V; Salzmann, C; Steiner, S; Steinkamp, O; Staumann, U; Tobin, M; Vollhardt, A; Bay, A; Bettler, M O; Blanc, F; Bressieux, J; Conti, G; Fave, V; Frei, R; Gauvin, N; Gonzalez, R; Haefeli, G; Hicheur, A; Keune, A; Luisier, J; Muresan, R; Nakada, T; Needham, M; Nicolas, L; Knecht, M; Perrin, A; Potterat, C; Schneider, O; Tran, M; Aquines Gutierrez, O; Bauer, C; Britsch, M; Hofmann, W; Maciuc, F; Schmelling, M; Voss, H; Adeva, B; Esperante, D; Fungueiriño Pazos, J; Gallas, A; Pazos-Alvarez, A; Pérez-Trigo, E; Pló Casasús, M; Rogríguez Pérez, P; Saborido, J; Vázquez, P; Iakovenko, V; Okhrimenko, O; Pugatch, V

    2010-01-01

    The LHCb Silicon Tracker is a silicon micro-strip detector with a sensitive area of 12 m$^2$ and a total of 272k readout channels. The Silicon Tracker consists of two parts that use different detector modules. The detector installation was completed by early summer 2008 and the commissioning without beam has reached its finals stage, successfully overcoming most of the encountered problems. Currently, the detector has more than 99% of the channels fully functioning. Commissioning with particles has started using beam-induced events from the LHC injection tests in 2008 and 2009. These events allowed initial studies of the detector performance. Especially, the detector modules could be aligned with an accuracy of about 20 $\\mu$m. Furthermore, with the first beam collisions that took place end of 2009 we could further study the performance and improve the alignment of the detector.

  16. Radiation hard programmable delay line for LHCb calorimeter upgrade

    Science.gov (United States)

    Mauricio, J.; Gascón, D.; Vilasís, X.; Picatoste, E.; Machefert, F.; Lefrancois, J.; Duarte, O.; Beigbeder, C.

    2014-01-01

    This paper 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 less than 5 ps jitter and 23 ps of DNL. The delay lines will be integrated into ICECAL, the LHCb calorimeter front-end analog signal processing 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 0.35 μm technology.

  17. Machine learning based global particle indentification algorithms at LHCb experiment

    CERN Multimedia

    Derkach, Denis; Likhomanenko, Tatiana; Rogozhnikov, Aleksei; Ratnikov, Fedor

    2017-01-01

    One of the most important aspects of data processing at LHC experiments is the particle identification (PID) algorithm. In LHCb, several different sub-detector systems provide PID information: the Ring Imaging CHerenkov (RICH) detector, the hadronic and electromagnetic calorimeters, and the muon chambers. To improve charged particle identification, several neural networks including a deep architecture and gradient boosting have been applied to data. These new approaches provide higher identification efficiencies than existing implementations for all charged particle types. It is also necessary to achieve a flat dependency between efficiencies and spectator variables such as particle momentum, in order to reduce systematic uncertainties during later stages of data analysis. For this purpose, "flat” algorithms that guarantee the flatness property for efficiencies have also been developed. This talk presents this new approach based on machine learning and its performance.

  18. Detailed Performance of the Outer Tracker at LHCb

    CERN Document Server

    Tuning, N

    2014-01-01

    The LHCb Outer Tracker is a gaseous detector covering an area of 5x6m2 with 12 double layers of straw tubes. Based on data of the first LHC running period from 2010 to 2012, the performance in terms of the single hit resolution and efficiency are presented. Details on the ionization length and subtle effects regarding signal reflections and the subsequent time-walk correction are given. 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, depending on the detailed implementation of the internal alignment of individual detector modules. 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.

  19. Operational aspects of the VELO cooling system of LHCb

    CERN Document Server

    Jans, E

    2014-01-01

    The VELO is a silicon strip detector that is positioned around the interaction region of LHCb. It is placed inside a secondary vacuum with respect to that of the LHC. The cooling system of the VELO is based on the bi-phase accumulator controlled method, using CO$_2$ as coolant. The main objective is the removal of the heat produced by the front-end electronics. Moreover, the leakage currents of the sensors are strongly reduced and thermal runaway is prevented. Since the sensors have been irradiated in Run 1 they should always be cooled to below $^-$5 $^{\\rm{o}}$C. The operational principle and main characteristics of the system are described, as well as the warning and safety systems that guarantee the safe operation of the detector. The few problems that have been encountered during the four years of continuous operation are discussed together with the solutions that have been implemented.

  20. Timing and Readout Contorl in the LHCb Upgraded Readout System

    CERN Document Server

    Alessio, Federico

    2016-01-01

    In 2019, the LHCb experiment at CERN will undergo a major upgrade where its detectors electronics and entire readout system will be changed to read-out events at the full LHC rate of 40 MHz. In this paper, the new timing, trigger and readout control system for such upgrade is reviewed. Particular attention is given to the distribution of the clock, timing and synchronization information across the entire readout system using generic FTTH technology like Passive Optical Networks. Moreover the system will be responsible to generically control the Front-End electronics by transmitting configuration data and receiving monitoring data, offloading the software control system from the heavy task of manipulating complex protocols of thousands of Front-End electronics devices. The way in which this was implemented is here reviewed with a description of results from first implementations of the system, including usages in test-benches, implementation of techniques for timing distribution and latency control."

  1. LHCb: DIRAC A community grid solution

    CERN Multimedia

    Tsaregorodtsev, A

    2007-01-01

    The DIRAC project began as a solution for the LHCb experiment at CERN to carry out massive Monte Carlo simulation and data processing on various distributed computing resources. Now it is evolving to a complete Grid solution for community of users such as LHCb.

  2. Hadronic b decays and $\\gamma$ at LHCb

    CERN Document Server

    AUTHOR|(CDS)2067638

    2014-01-01

    The LHCb experiment is ideally suited to the study of decays involving b quarks to fully hadronic final states. In these proceedings I summarise the status of the LHCb $\\gamma$ combination and present several recent analyses involving beauty baryon and meson decays.

  3. 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 ...

  4. 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...

  5. 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...

  6. Contribution to the Development of the LHCb Vertex Locator Readout Electronics

    CERN Document Server

    Ermoline, Iouri

    The LHCb experiment is being built at the future LHC accelerator at CERN. It is a forward single-arm spectrometer dedicated to precision measurements of CP violation and rare decays in the b quark sector. Presently it is finishing its R&D and final design stage. The construction already started for the magnet and calorimeters. In the Standard Model, CP violation arises via the complex phase of the 3 x 3 CKM (Cabibbo-Kobayashi-Maskawa) quark mixing matrix. The LHCb experiment will test the unitarity of this matrix by measuring in several theoretically unrelated ways all angles and sides of the so-called "unitary triangle". This will allow to over-constrain the model and - hopefully - to exhibit inconsistencies which will be a signal of physics beyond the Standard Model. The Vertex reconstruction is a fundamental requirement for the LHCb experiment. Displaced secondary vertices are a distinctive feature of b-hadron decays. This signature is used in the LHCb topology trigger. The Vertex Locator (VeLo) has to...

  7. LHCb: Not just a precision experiment but also a detector ready for discoveries

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    The first proton run has confirmed that LHCb has powerful capabilities in the field of flavour physics and that many possible signatures of non-Standard Model effects are within the experiment's reach. Furthermore, this run has confirmed that LHCb is able to make important contributions beyond the flavour sector. The collaboration is working on a Letter of Intent for an upgrade, which will take advantage of the open geometry of the experiment, and will aim at improved sensitivity both in the flavour sector and in a wider physics programme.   Unlike ATLAS and CMS, LHCb does not have a cylindrical geometry. Rather, it is laid out horizontally along the beam line. This layout prevented the collaboration from testing the detector with cosmic rays prior to starting to collect data from the LHC collisions. However, despite these more challenging initial conditions, LHCb was soon able to demonstrate excellent performance during the LHC’s first proton run. “Just a few years ago, we co...

  8. First LHCb results from pA and Pb-Pb collisions

    CERN Document Server

    Massacrier, L.

    2016-01-01

    In 2015, the LHCb collaboration endorsed the proposal to pursue an ambitious heavy-ion physics program. In 2013, LHCb has demonstrated its capabilities to operate successfully in p-Pb and Pb-p collisions, leading already to several important publications in the field. The measurements of the nuclear modification factor and forward-backward production of prompt and displaced J/$\\psi$, $\\psi$(2S) and $\\Upsilon$(1S) states, as well as the production of prompt $D^{0}$ mesons, have allowed to extend the knowledge of Cold Nuclear Matter effects on open heavy flavours and quarkonium production. The measurement of Z-boson production, important to constrain nuclear PDFs, and the measurement of two-particle angular correlations, probing collective effects in the dense environment of high energy collisions, have also been performed. Furthermore, LHCb is the only experiment at the LHC that can be operated in fixed-target mode, owing to the injection of a small amount of gas inside the LHCb collision area. There have been...

  9. The search for τ→μμμ at LHCb

    Energy Technology Data Exchange (ETDEWEB)

    Seyfert, Paul

    2015-01-14

    The charged lepton flavour violating decay τ→μμμ is searched for, using the LHCb experiment. Violation of lepton flavour in the charged lepton sector is unobserved to date. Within the Standard Model of particle physics including neutrino oscillation, the branching fraction is expected to be umeasureable small and an observation would be an unambiguous sign for physics beyond the Standard Model. Over 10{sup 11} τ leptons have been produced in proton-proton collisions at LHCb during the first run of the LHC. Most of them in decays of D{sub s} mesons. Compared to previous experiments at electron-positron colliders, the signature of τ→μμμ is harder to identify in hadronic collisions and background processes are more abundant. A multivariate event classification has been developed to distinguish a possible signal from background events. The number of τ leptons produced in the LHCb acceptance is estimated by measuring the yield of D{sub s}→φ(μμ)π decays. The sensitivity reached by analysing LHCb data corresponding to 3 fb{sup -1} is sufficient to constrain the branching fraction of τ→μμμ to be smaller than 7.1 x 10{sup -8} at 90% confidence level.

  10. Heavy ion and fixed target physics at LHCb: results and prospects

    CERN Document Server

    CERN. Geneva

    2016-01-01

    In 2015, the LHCb collaboration endorsed the proposal to pursue an ambitious heavy ion physics program. In 2013, LHCb has demonstrated its capabilities to operate successfully in p-Pb and Pb-p collisions, leading already to several important publications in the field. The measurements of the nuclear modification factors and forward-backward production of prompt and displaced J/psi, psi(2S) and Upsilon states, as well as the production of prompt D0 mesons, have allowed to extend the knowledge of Cold Nuclear Matter effects on open heavy flavours and quarkonium production. The measurement of Z-boson production, important to constrain nuclear PDFs, and the measurement of two-particle angular correlations, probing collective effects in the dense environment of high energy collisions, have also been performed. Furthermore, LHCb is the only experiment at the LHC that can be operated in fixed-target mode, owing to the injection of a small amount of gas inside the LHCb collision area. There have been several p-gas an...

  11. LHC Phenomenology

    CERN Document Server

    Logan, Heather E

    2011-01-01

    The analyses of the first 1-2/fb of Large Hadron Collider (LHC) data are already having significant impacts on a wide range of models. In this talk I give my perspective on why we expect to find new physics at the LHC, and how such a discovery might unfold.

  12. 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.

  13. 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.

  14. Real time analysis with the upgraded LHCb trigger in Run-III

    CERN Multimedia

    Szumlak, Tomasz

    2016-01-01

    The current LHCb trigger system consists of a hardware level, which reduces the LHC bunch-crossing rate of 40 MHz to 1 MHz, a rate at which the entire detector is read out. A second level, implemented in a farm of around 20k parallel processing CPUs, the event rate is reduced to around 12.5 kHz. The LHCb experiment plans a major upgrade of the detector and DAQ system in the LHC long shutdown II (2018-2019 ). In this upgrade, a purely software based trigger system is being developed and it will have to process the full 30 MHz of bunch crossings with inelastic collisions. LHCb will also receive a factor of 5 increase in the instantaneous luminosity, which further contributes to the challenge of reconstructing and selecting events in real time with the CPU farm. We discuss the plans and progress towards achieving efficient reconstruction and selection with a 30 MHz throughput. Another challenge is to exploit the increased signal rate that results from removing the 1 MHz readout bottleneck, combined with the high...

  15. Contribution to the development of the acquisition electronics for the LHCb experiment

    CERN Document Server

    AUTHOR|(CDS)2069680

    2004-01-01

    The LHCb experiment is one of the four large particle detectors currently under construction at the LHC accelerator at CERN. It is a forward single-arm spectrometer to precision measurements of CP violation and rare decays in the b quark sector. In the Standard Model CP violation arises via the complex phase of the 3x3 CKM quark mixing matrix. The LHCb experiment will test the unitarity of this matrix by measuring in several theoretically unrelated ways all angles and all sides of the unitarity triangle. This will allow to over-constrain the model and - hopefully - to exhibit inconsistencies which will be a signal of physics beyond the Standard Model. The LHCb detector consists of roughly one million sensors and is read out every LHC bunch crossing at 40 MHz. In the subsequent selection of events a multilevel trigger scheme is applied. The data is required to reside in the radiation environment on the front-end chips until the first level trigger (L0) decision is taken. For the second level trigger (L1) proce...

  16. Physics at 13 TeV: LHCb - a new data-processing strategy

    CERN Multimedia

    Antonella Del Rosso

    2014-01-01

    Originally, the LHCb detector was designed for operation with moderate luminosity and low pile-up. However, in 2010, the collaboration opted for “luminosity levelling”, a novel solution which allows the experiment to adapt automatically to normal variations in luminosity which occur during an LHC run.   In this way, the detector operates optimally at all times. “For the second LHC run, we will have to redefine the luminosity, to adapt to the conditions at the new energy of 13 TeV,” explains Patrick Koppenburg, physics coordinator of the LHCb collaboration. “However, the most important experimental challenge for us will be the new trigger system.” The trigger rapidly sorts the most interesting data from the data that can be discarded without a significant loss of information. The zero-level (i.e. the first level) trigger system of LHCb “only” lets through one sixteenth of the initial data, but even that is too muc...

  17. Live facebook event on the 2017 LHC physics season kick-off

    CERN Multimedia

    2017-01-01

    Live facebook event on the 2017 LHC physics season kick-off covering the start of the data taking season for the LHC experiments for the first time this year, from the CERN control center, as it happens. CERN host Paola Catapano moderates a round table and Q/A session with physicists from the LHC Machine (Jamie Boyd) and the LHC experiments: Alexander Oh (ATLAS) Anne Dabrowski (CMS), Despina Hatzifodiatou (ALICE) and Barbara Storaci (LHCb). Questions from the live audience to the physicists.

  18. Študij sevalnih poškodb silicijevih detektorjev za eksperimente z visoko luminoznostjo na trkalniku LHC

    CERN Document Server

    Žontar, Dejan; Mikuž, Marko

    1998-01-01

    Radiation damage of the silicon bulk will play an important role in the vertex detectors in the future experiments at LHC. To study its macroscopic effects, high resistivity p-n-n diodes were irradiated with neutrons at the TRIGA research reactor of Jožef Stefan Institute in Ljubljana. Irradiation fluences were in the range from 10^13 to 2.5x10^14 cm2 of equivalent 1 MeV neutrons. Development of effective doping concentration and reverse current during and after irradiations was studied under controlled conditions (bias, temperature). Long term annealing of effective doping concentration was studied to determine the dynamics of the process responsible. Results obtained from a set of unbiased diodes kept at 20"C gave conclusive evidence that, at least during the initial stage, time development can be described by a first order process. Flux dependence of defect creation has been checked in the flux range from 2x10^8 to approx 5x10^15 n/cm2s. No significant difference among the samples was observed in a...

  19. Thermal study and design of a cooling system for the electronics boards of the LHCb SciFi tracker

    CERN Multimedia

    Hamrat, Sonia

    2017-01-01

    The LHCb detector, one of the four large LHC detectors, has launched a major upgrade program with the goal to enormously boost the rate and selectivity of the data taking. The LHCb upgrade comprises the complete replacement of several sub-detectors, the substantial upgrade of the front-end electronics and the introduction of a new paradigm, namely the suppression of a hardware trigger by reading out the whole experiment synchronously at a rate of 40 MHz. The high readout frequency, unprecedented in a particle physics experiment, and the harsh radiation environment related to the increased LHC intensity, are the major challenges to be addressed by the new sub-detectors. The development and construction of a new large-scale tracking detector, based on a novel scintillating fibre (SciFi) technology, read out with silicon photomultipliers (SiPM), is one of the key projects of the LHCb upgrade program. The LHCb SciFi detector will count more than 500,000 channels. It is composed of 12 layers arranged in 3 tracking...

  20. 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.

  1. 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.

  2. 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...

  3. 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.

  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. Half way round the LHC

    CERN Multimedia

    CERN Bulletin

    The LHC operations teams are preparing the machine for circulating beams and things are going very smoothly. ALICE and LHCb are getting used to observing particle tracks coming from the LHC beams. During the weekend of 7-8 November, CMS also  saw its first signals from beams dumped just upstream of  the experiment cavern.   Operators in the CMS control room observe the good performance of their detector. Particles are smoothly making their way around the 27 km circumference of the LHC. Last weekend (7-8 November), the first bunches of injection energy protons completed their journey (anti-clockwise) through three octants of the LHC’s circumference and were dumped in a collimator just before entering the CMS cavern. The particles produced by the impact of the protons on the tertiary collimators (used to stop the beam) left their tracks in the calorimeters and the muon chambers of the experiment. The more delicate inner detectors were switched off for protection reasons....

  6. Automated Grid Monitoring for the LHCb Experiment Through HammerCloud

    CERN Document Server

    Dice, Bradley

    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. Triple-GEM detectors for the innermost region of the muon apparatus at the LHCb experiment

    CERN Document Server

    Poli-Lener, M; Bencivenni, G

    2005-01-01

    The LHCb experiment will take place at the future LHC accelerator at CERN and will start in 2007. It is a single arm spectrometer to precision measurements of CP violation and rare decays in the b quark sector. Recent experimental results have shown that CP violation is large in this sector. LHCb is designed with a robust and flexible trigger in order to extensively gain access to a wide spread of different physical processes involving the beauty particles. This will allow to over-constrain the Standard Model predictions about $\\mathcal{CP}$ violation, and to discover any possible inconsistency, which would reveal the presence of ''New Physics''. The work presented in this thesis has two main parts: the development of a charged particle detector based on Gas Electron Multiplication (GEM) and the study of luminosity measurements with the physical channels $Z^{0} \\rightarrow \\mu^{+} \\mu^{-}$ and $W^{\\pm} \\rightarrow \\mu^{\\pm} \

  8. A stand-alone track reconstruction algorithm for the scintillating fibre tracker at the LHCb upgrade

    CERN Multimedia

    Quagliani, Renato

    2017-01-01

    The LHCb upgrade detector project foresees the presence of a scintillating fiber tracker (SciFi) to be used during the LHC Run III, starting in 2020. The instantaneous luminosity will be increased up to $2\\times10^{33}$, five times larger than in Run II and a full software event reconstruction will be performed at the full bunch crossing rate by the trigger. The new running conditions, and the tighter timing constraints in the software trigger, represent a big challenge for track reconstruction. This poster presents the design and performance of a novel algorithm that has been developed to reconstruct track segments using solely hits from the SciFi. This algorithm is crucial for the reconstruction of tracks originating from long-lived particles such as $K_{S}^{0}$ and $\\Lambda$ and allows to greatly enhance the physics potential and capabilities of the LHCb upgrade when compared to its previous implementation.

  9. Fast simulation options in LHCb from ReDecay to fully parametrised

    CERN Multimedia

    Muller, Dominik

    2017-01-01

    With the steady increase in the precision of flavour physics measurements with data from Run 2 of the LHC, the LHCb experiment requires simulated data samples of ever increasing magnitude to study the detector response in detail. However, relying on an increase of computing resources available for the production of simulated samples will not suffice to achieve this goal. Therefore, multiple efforts are currently being investigated to reduce the time needed to simulate an event. This talk presents a summary of those efforts in LHCb, focusing on the newest developments: re-using parts of previously simulated events and a fully parametric detector description using the DELPHES framework. The former merges a simulation of an underlying event multiple times with signal decays simulated separately, achieving an order of magnitude increase in speed with identical precision. The latter provides a parametric solution replacing the full, GEANT4-based simulation, including the smearing of particles' energies, efficienci...

  10. Performance of the LHCb Detector during 2010-2011 data taking

    CERN Document Server

    van Beuzekom, Martin

    2012-01-01

    The status and performance of the LHCb detector during the physics LHC physics run is described. The LHCb detector has a number of notable features including: 12 micron resolution in the transverse plane on 30-35 track primary vertices, pion and kaon separation from 1 to 100 GeV, and 1 MHz full readout of all sub-systems. The detector is being operating above its design luminosity and is comprised of a silicon vertex detector, silicon and straw-tube tracking systems, ring imaging Cherenkov particle identification systems, electromagnetic and hadronic calorimetry, and muon systems. Hardware and software based trigger levels are utilised to efficiently select leptonically and hadronically decay beauty and charm hadrons. The alignment, tracking and particle identification performance will be discussed.

  11. Forward Physics at LHCb – Prospects for the Study of Diffractive Interactions

    CERN Document Server

    Schmelling, Michael

    2010-01-01

    LHCb, the smallest of the large LHC experiments is a forward spectrometer covering the angular range 2 < $\\eta$ < 5 with tracking, calorimetry and particle identification. Partial coverage of the backward hemisphere is also provided by the vertex detector (Vertex Locator, VeLo), a silicon strip detector surrounding the interaction region. Generator level Monte Carlo studies suggest that using the VeLo to ask for a rapidity gap of $\\delta\\eta$ = 2.5 in the backward region allows to select event samples dominated by diffractive processes. Making use of the excellent tracking, vertexing and particle identification capabilities of the LHCb detector, the characteristics of diffractive particle production thus can be studied in detail in the forward acceptance covered by the experiment.

  12. Novel Real-time Calibration and Alignment Procedure for LHCb Run II

    CERN Multimedia

    Prouve, Claire

    2016-01-01

    In order to achieve optimal detector performance the LHCb experiment has introduced a novel real-time detector alignment and calibration strategy for Run II of the LHC. For the alignment tasks, data is collected and processed at the beginning of each fill while the calibrations are performed for each run. This real time alignment and calibration allows the same constants being used in both the online and offline reconstruction, thus improving the correlation between triggered and offline selected events. Additionally the newly computed alignment and calibration constants can be instantly used in the trigger, making it more efficient. The online alignment and calibration of the RICH detectors also enable the use of hadronic particle identification in the trigger. The computing time constraints are met through the use of a new dedicated framework using the multi-core farm infrastructure for the LHCb trigger. An overview of all alignment and calibration tasks is presented and their performance is shown.

  13. LHC Report: Ticking over

    CERN Multimedia

    Mike Lamont for the LHC Team

    2012-01-01

    The past two weeks have seen luminosity production rates vary somewhat but the overall upwards slope has remained steady. Over 17 fb-1 have been delivered to both ATLAS and CMS; LHCb is also doing well, with around 1.6 fb-1 delivered so far in 2012. The proton physics production also slotted in a five-day machine development period (Monday 8 to Saturday 13 October).   When producing the LHC beam in the PS, some parasitic low-intensity satellite bunches are formed 25 ns from the main bunches, which are spaced by 50 ns. ALICE, whose detector is designed to work with relatively low collision rates, has been taking data from satellite-main collisions. The population of these satellites has recently been increased thanks to gentle tweaks by the PS radio frequency experts. This has increased the peak luminosity in ALICE and will help them to reach their proton-proton integrated luminosity goal for the year. The October machine development programme was a mixed bag. While some studies were aimed at sho...

  14. The LHCb magnet design team

    CERN Document Server

    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. Event Data Definition in LHCb

    CERN Document Server

    Cattaneo, M; Frank, M; Vila, P M; Miksch, S; Roiser, S; Cattaneo, Marco; Corti, Gloria; Frank, Markus; Vila, Pere Mato; Miksch, Silvia; Roiser, Stefan

    2003-01-01

    We present the approach used for defining the event object model for the LHCb experiment. This approach is based on a high level modelling language, which is independent of the programming language used in the current implementation of the event data processing software. The different possibilities of object modelling languages are evaluated, and the advantages of a dedicated model based on XML over other possible candidates are shown. After a description of the language itself, we explain the benefits obtained by applying this approach in the description of the event model of an experiment such as LHCb. Examples of these benefits are uniform and coherent mapping of the object model to the implementation language across the experiment software development teams, easy maintenance of the event model, conformance to experiment coding rules, etc. The description of the object model is parsed by means of a so called front-end which allows to feed several back-ends. We give an introduction to the model itself and t...

  16. 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.

  17. The LHC

    CERN Multimedia

    2002-01-01

    The LHC will use the latest technologies on an enormous scale. 8000 superconducting magnets will keep the beams on track. The entire 27 km ring will be cooled by 700 000 litres of liquid helium to a temperature of -271 degrees Celsius , making the LHC the world's largest superconducting installation. Conventional superconducting wire will form the magnet coils, while high-temperature superconductors will carry a total of 2 300 000 amperes from the power supplies into the magnet cryostat

  18. Hangout With CERN: LHC and the Grid - The world is our calculator (S02E03)

    CERN Multimedia

    Kahle, Kate

    2013-01-01

    With around 25 Petabytes (25 million Gigabytes) of data generated per year from CERN's Large Hadron Collider, global computing is the only way to store, distribute and analyse this mountain of information. The world is our calculator!In this hangout, IT experts from CERN and the experiments talk about the Worldwide LHC Computing Grid (WLCG) project - a global collaboration of more than 170 computing centres in 36 countries. What happens to the data when it leaves the LHC? How does this global calculator work?ATLAS physicist Steven Goldfarb is joined by ATLAS Computing Coordinator Richard Mount and visiting Swedish student Buster Berggren, along with CERN IT experts Oliver Keeble and Markus Schultz with Swedish student Filip af Malmborg at the CERN computer centre, and LHCb Grid operations expert Stefan Roiser and LHCb physicist Patrick Koppenburg at the LHCb offline control room. ALICE physicist Ken Read monitors questions coming in from social media. Recorded live on 7 February 2013.

  19. Charmonium production in pp collisions with ALICE at the LHC

    CERN Document Server

    Hugo, Pereira Da Costa

    2016-01-01

    We report on forward-rapidity charmonium production in pp collisions at a center of mass energy $\\sqrt{s} = 13$ TeV, as measured by ALICE at the LHC. Differential cross sections for both J/{\\psi} and {\\psi}(2S) are presented as a function of the charmonium transverse momentum and rapidity. Results are compared to similar measurements performed by LHCb, to lower energy measurements and to state of the art model calculations.

  20. LHCb siliicon detectors: the Run 1 to Run 2 transition and first experience of Run 2

    CERN Document Server

    Rinnert, Kurt

    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. The detector includes a high precision tracking system consisting of a silicon-strip vertex detector (VELO) surrounding the pp interaction region, a large- area silicon-strip detector located upstream of a dipole magnet (TT), and three stations of silicon- strip detectors (IT) and straw drift tubes placed downstream (OT). The operational transition of the silicon detectors VELO, TT and IT from LHC Run 1 to Run 2 and first Run 2 experiences will be presented. During the long shutdown of the LHC the silicon detectors have been maintained in a safe state and operated regularly to validate changes in the control infrastructure, new operational procedures, updates to the alarm systems and monitoring software. In addition, there have been some infrastructure related challenges due to maintenance performed in the vicinity of the silicon detectors that will be discussed. The LHCb silicon dete...

  1. 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...

  2. 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.

  3. The $X(3872)$ and the search for its bottomonium counterpart at the LHC

    CERN Document Server

    Toms, Konstantin; The ATLAS collaboration

    2016-01-01

    We present results on $X(3872)$ particle studies at three LHC experiments: ATLAS, CMS, and LHCb. Production cross section measurements are reported, as well as determination of the $X(3872)$ quantum numbers. The search of the $X(3872)$ bottomonium counterpart is also described.

  4. Scintillating Fibre Tracker Front-End Electronics for LHCb upgrade

    CERN Multimedia

    Comerma, A

    2014-01-01

    The LHCb detector will be upgraded during the next LHC shutdown in 2018/19. The tracker system will undergo major changes. Its components will be replaced by new technologies in order to cope with the increased hit occupancy and the higher radiation dose. A detector made of scintillating fibres read out by silicon photomultipliers (SiPM) is envisaged 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. The detector will consist of 12 planes of 5 to 6 layers of 250μm fibres stacked covering a total area of 5x6m^2 . The desired spacial resolution on the reconstructed hit is 100μm. SiPMs have been adapted to the detector geometry reducing the dead area between channels. A total of 64 channels are arranged in a single die with common cathode connection and channel size of 0.23x1.32mm^2 . Two dies are packaged together with only 0.25mm of dead area between them. Radiation tolerance of such devices is ...

  5. Double Heavy Flavour Production at LHCb

    CERN Document Server

    Li, Yiming

    2017-01-01

    This proceeding summarises the latest LHCb results on associated heavy flavour productions, including double charm production and associated bottomonia and charm production. This article belongs to the Topical Collection “New Observables in Quarkonium Production”.

  6. Radiation damage of LHCb electromagnetic calorimeter

    CERN Document Server

    Barsuk, S; Kirichenko, V; Korolko, I; Malyshev, S; Rusinov, V Yu; Tarkovski, E

    2000-01-01

    Addressed is an extensive irradiation test program carried on to establish proper design and materials to build electromagnetic calorimeter that matches radiation conditions of the LHCb experiment at CERN. The results obtained are compared with measurements by other groups.

  7. 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.

  8. CPV in beauty decays with LHCb

    CERN Document Server

    Meier, Frank

    2016-01-01

    During 2011 and 2012, $pp$ collision data corresponding to integrated luminosities of 1fb$^{-1}$ at a centre-of-mass energy of 7 TeV and 2fb$^{-1}$ at 8 TeV have been collected with the LHCb detector. This dataset has allowed LHCb to measure with unprecedented precision observables relating to the CKM unitary triangles. In these proceedings I describe measurements sensitive to $\\gamma$, the least well constrained unitary triangle angle.

  9. The RICH detectors of the LHCb experiment

    CERN Document Server

    Perego, D L

    2009-01-01

    The status of the Ring Imaging Cherenkov (RICH) system of the LHCb experiment is presented. The commissioning of both RICH detectors is in an advanced phase and they are ready to take data at the start–up of the Large Hadron Collider. The detectors provide essential contributions to the LHCb physics program. The expected performance of the RICH system, the pattern recognition and the particle identification is discussed.

  10. Studies of Soft QCD at LHCb

    Directory of Open Access Journals (Sweden)

    Grecu Alexandru T.

    2013-11-01

    Full Text Available Due to its unique pseudorapidity coverage and the possibility of extending measurements to low transverse momenta, LHCb provides important input to the understanding of particle production in a kinematic range where QCD models have large uncertainties. Measurements of charged, strange and charmed particle production and energy flow are performed in the approximate pseudorapidity range 2 < η < 5, which corresponds to the acceptance of the LHCb spectrometer. The results are compared to predictions given by several Monte Carlo event generators.

  11. Prospects for the search of at LHCb

    Science.gov (United States)

    Lucio Martinez, Miriam

    2017-01-01

    The sensitivity of the LHCb experiment to is analyzed in light of the 2011, 2012 and 2016 data and the oportunity of having a full software trigger with the LHCb upgrade. Two strategies are considered: the full reconstruction of the decay products and the partial reconstruction using only the dilepton pair and kinematic constraints. In both cases, the sensitivity achieved can surpass the world's current best measurement. Both approaches could be statistically combined to further improve the result.

  12. Heavy Flavour and Quarkonia production at LHCb

    CERN Document Server

    Mueller, Katharina

    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.

  13. 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.

  14. Central Exclusive Production at LHCb

    CERN Document Server

    McNulty, Ronan

    2016-01-01

    Central Exclusive Production (CEP) is a unique process at hadron machines in which particles are produced via colourless propagators. LHCb have measured the cross-sections for the CEP of vector mesons, $J/\\psi,\\psi(2S),\\Upsilon(1S),\\Upsilon(2S)$ and $\\Upsilon(3S)$, which are photo-produced. In the double pomeron exchange process, preliminary measurements have been made of $\\chi_{c0},\\chi_{c1}, \\chi_{c2}$ meson production while the first observations of the CEP of pairs of charmonia, $J/\\psi J/\\psi$ and $J/\\psi \\psi(2S)$, have been made and limits obtained on the pair production of other charmonia.

  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. Amplitude Analysis of $D^+ \\rightarrow K^- K^+ \\pi^+$ Decay with LHCb 2012 Data and RF-foil Simulations for the LHCb Upgrade

    CERN Document Server

    AUTHOR|(CDS)2073713

    The $D^{+} \\to K^{-}K^{+}\\pi^{+}$ decay is a hadronic process dominated by resonant intermediate states. In order to quantify and understand the nature of each contribution, an amplitude analysis must be performed. The most common approach for this task is the Isobar Model, where each resonant contribution is described by a combination of Breit-Wigner functions, form factors and angular distribution functions. Achieving a precise description using the Isobar model is a challenging task since it does not provide an adequate framework for broad, overlapping structures typical from the S-wave amplitudes. Due to the huge statistics provided by LHCb, subtle effects might become relevant to our model. The LHCb experiment is going through an upgrade process for the next LHC run period. LHC will provide a much higher luminosity and all subsystems are required to upgrade in order to improve the experiment performance and make good use of the available data. The Vertex Locator, in particular, will be upgraded to a hybr...

  17. 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...

  18. DIRAC: reliable data management for LHCb

    Science.gov (United States)

    Smith, A. C.; Tsaregorodtsev, A.

    2008-07-01

    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.

  19. A High-Efficiency and High-Resolution Straw Tube Tracker for the LHCb Experiment

    CERN Document Server

    Tuning, Niels

    2005-01-01

    The Outer Tracker detector for the LHCb experiment at CERN will provide accurate position information on the charged particles in B-decays. It is crucial to accurately and efficiently detect these particles, in the high-density particle environment of the LHC. For this, the Outer Tracker is being constructed, consisting of $\\sim$ 55,000 straw tubes, covering in total an area of 360 m$^2$ of double layers. At present, approximately 90% of the detector has been constructed and fully tested. In addition, a beam test has been performed at DESY, Hamburg, to validate the final read-out electronics, in terms of efficiency, position resolution, noise and cross talk.

  20. Performance Studies of Pixel Hybrid Photon Detectors for the LHCb RICH Counters

    CERN Document Server

    Aglieri Rinella, G; Piedigrossi, D; Van Lysebetten, A

    2004-01-01

    The Pixel Hybrid Photon Detector is a vacuum tube with a multi-alkali photo cathode, high voltage cross-focused electron optics and an anode consisting of a silicon pixel detector bump-bonded to a readout CMOS electronic chip fully encapsulated in the device. The Pixel HPD fulfils the requirements of the Ring Imaging Cherenkov counters of the LHCb experiment at LHC. The performances of the Pixel HPD will be discussed with reference to laboratory measurements, Cherenkov light imaging in recent beam tests, image distortions due to a magnetic field.

  1. Performance studies of pixel hybrid photon detectors for the LHCb RICH counters

    CERN Document Server

    Aglieri-Rinella, G; Piedigrossi, D; Van Lysebetten, A

    2006-01-01

    The Pixel Hybrid Photon Detector is a vacuum tube with a multi-alkali photo cathode, high voltage cross-focused electron optics and an anode consisting of a silicon pixel detector bump-bonded to a readout CMOS electronic chip fully encapsulated in the device. The Pixel HPD fulfils the requirements of the Ring Imaging Cherenkov counters of the LHCb experiment at LHC. The performances of the Pixel HPD will be discussed with reference to laboratory measurements, Cherenkov light imaging in recent beam tests, image distortions due to a magnetic field.

  2. Open charm meson production at LHC*

    Directory of Open Access Journals (Sweden)

    Luszczak Marta

    2012-12-01

    Full Text Available We discuss charm production at the LHC. The production of single cc¯$car c$ pairs is calculated in the kt-factorization approach. We use Kimber-Martin-Ryskin unintegrated gluon distributions in the proton. The hadronization is included with the help of Peterson fragmentation functions. Transverse momentum and pseudorapidity distributions of charmed mesons are presented and compared to recent results of the ALICE, LHCb and ATLAS collaborations. Furthermore we discuss production of two pairs of cc¯ $car c$ within a simple formalism of double-parton scattering (DPS. Surprisingly large cross sections, comparable to single-parton scattering (SPS, are predicted for LHC energies. We discuss perspectives how to identify the double scattering contribution. We predict much larger cross section for large rapidity distance between charm quarks from different hard parton scatterings compared to single scattering.

  3. 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.

  4. Reconstruction and calibration strategies for the LHCb RICH detector

    CERN Document Server

    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

  5. LHCb experiment announces the unambiguous observation of an exotic particle

    CERN Multimedia

    2014-01-01

    Short interview to pier Luigi Campana, LHCb spokesperson, and Richard Jacobsson, LHCb physicist, on the unambiguous observation of an exotic particle which cannot be classified within the traditional quark model

  6. 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

  7. 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.

  8. LHC Create

    CERN Document Server

    CERN. Geneva

    2017-01-01

    LHC Create is an upcoming 2-day workshop held at IdeaSquare in November. Participants from CERN and IPAC school of design will compete to design an exhibit that explains why CERN does what it does. The winner will have their exhibit fully realised and made available to experiments, institutes, and tourism agencies around the world.

  9. 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...

  10. Contribution to the Development of the LHCb vertex locator and study of rare semileptonic decays

    CERN Document Server

    AUTHOR|(CDS)2067796

    2002-01-01

    The LHCb experiment will take place at the future LHC accelerator at CERN and will start in 2006. It is a forward single-arm spectrometer dedicated to precision measurements of CP violation and rare decays in the b quark sector. Recent experimental results have shown that CP violation is large in this sector. In the Standard Model, CP violation arises via the complex phase of the 3x3 CKM quark mixing matrix. The LHCb experiment will test the unitarity of this matrix by measuring in several theoretically unrelated ways all angles and all sides of the unitarity triangle. This will allow to over-constrain the model and - hopefully - to exhibit inconsistencies which will be a signal of physics beyond the Standard Model. This thesis presents the sensitivity of the LHCb experiment to the recently observed flavour changing neutral current decays b → lld,s. Comparing the inclusive branching ratios of the B → μμXs and B → μμXd decays allows to extract the CKM matrix elements ratio Vtd/Vts. This constrains t...

  11. Experimental mini-review on $R(D)$ and $R(D^*)$ measurements at LHCb

    CERN Document Server

    Bozzi, Concezio

    2017-01-01

    The large cross section for the production of b quark pairs at the LHC and the large boost of the resulting b -hadrons, combined to the excellent vertexing capabilities of the LHCb detector, enable precise measurements of semi-tauonic decays in an hadronic environment. By using a data sample of pp collisions, corresponding to 3 fb − 1 integrated luminosity, LHCb has measured the ratio R ( D ∗ ) of branching fractions for the B 0 → D ∗− τ + ν τ and B 0 → D ∗− μ + ν μ decays. The result R ( D ∗ ) = 0 . 336 ± 0 . 027 ± 0 . 030 is in tension with the Standard Model prediction at the 2 σ level and, when combined with other measurements from the B Factories on decays with D and D ∗ mesons in the final states, increases the discrepancy with the Standard Model at the 4 σ level. In this review, the LHCb measurement is described and an outlook on other possible studies in the domain of semitauonic decays of b -hadrons is given.

  12. Evaporative CO2 microchannel cooling for the LHCb VELO pixel upgrade

    Science.gov (United States)

    de Aguiar Francisco, O. A.; Buytaert, J.; Collins, P.; Dumps, R.; John, M.; Mapelli, A.; Romagnoli, G.

    2015-05-01

    The LHCb Vertex Detector (VELO) will be upgraded in 2018 to a lightweight pixel detector capable of 40 MHz readout and operation in very close proximity to the LHC beams. The thermal management of the system will be provided by evaporative CO2 circulating in microchannels embedded within thin silicon plates. This solution has been selected due to the excellent thermal efficiency, the absence of thermal expansion mismatch with silicon ASICs and sensors, the radiation hardness of CO2, and very low contribution to the material budget. Although microchannel cooling is gaining considerable attention for applications related to microelectronics, it is still a novel technology for particle physics experiments, in particular when combined with evaporative CO2 cooling. The R&D effort for LHCb is focused on the design and layout of the channels together with a fluidic connector and its attachment which must withstand pressures up to 170 bar. Even distribution of the coolant is ensured by means of the use of restrictions implemented before the entrance to a race track like layout of the main cooling channels. The coolant flow and pressure drop have been simulated as well as the thermal performance of the device. This proceeding describes the design and optimization of the cooling system for LHCb and the latest prototyping results.

  13. An ASIC for fast single photon counting in the LHCb RICH upgrade

    Science.gov (United States)

    Gotti, C.

    2017-03-01

    The LHCb experiment will be upgraded during the second LHC long shutdown (years 2019–2020) to operate at higher luminosity. The new triggerless architecture of LHCb requires data from the entire detector to be read out at 40 MHz. The basic element of the front-end electronics of the Ring Imaging Cherenkov (RICH) detector upgrade is the "Elementary Cell" (EC), a readout system for multianode photomultiplier tubes designed to minimise parasitic capacitance at the anodes, to obtain a fast readout with low noise and low crosstalk. At the heart of the EC is the CLARO, an 8 channel, low power and radiation hard front-end ASIC designed in 0.35 μm CMOS technology. Each channel compares the charge signals from the photomultiplier anodes with a programmable threshold, and gives a digital pulse at the output when the threshold is exceeded. Baseline recovery occurs in less than 25 ns for typical single photon signals. In the LHCb RICH upgrade environment, the chips will have to withstand radiation up to a total ionising dose of 2 kGy (200 krad) and neutron and hadron fluences up to 03×112 cm‑2 and following irradiation, the chips have been shown to tolerate such doses with a margin of safety.

  14. The LHCb Experience on the Grid from the DIRAC Accounting Data

    CERN Document Server

    Puig, A; Graciani, R; Casajús, A

    2011-01-01

    DIRAC is the software framework developed by LHCb to manage all its computing operations on the Grid. Since 2003 it has been used for large scale Monte Carlo simulation productions and for user analysis of these data. Since the end of 2009, with the start-up of LHC, DIRAC also takes care of the distribution, reconstruction, selection and analysis of the physics data taken by the detector apparatus. During 2009, DIRAC executed almost 5 million jobs for LHCb. In order to execute this workload slightly over 6 million of pilot jobs were submitted, out of which approximately one third were aborted by the Grid infrastructure. In 2010, thanks to their improved efficiency, DIRAC pilots are able, on average, to match and execute between 2 and 3 LHCb jobs during their lifetime, largely reducing the load on the Grid infrastructure. Given the large amount of submitted jobs and used resources, it becomes essential to store detailed information about their execution to track the behaviour of the system. The DIRAC Accountin...

  15. The LHCb Experience on the Grid from the DIRAC Accounting Data

    CERN Document Server

    Casajús, A; Puig, A; Vázquez, R

    2011-01-01

    DIRAC is the software framework developed by LHCb to manage all its computing operations on the Grid. Since 2003 it has been used for large scale Monte Carlo simulation productions and for user analysis of these data. Since the end of 2009, with the start-up of LHC, DIRAC also takes care of the distribution, reconstruction, selection and analysis of the physics data taken by the detector apparatus. During 2009, DIRAC executed almost 5 million jobs for LHCb. In order to execute this workload slightly over 6 million of pilot jobs were submitted, out of which approximately one third were aborted by the Grid infrastructure. In 2010, thanks to their improved efficiency, DIRAC pilots are able, on average, to match and execute between 2 and 3 LHCb jobs during their lifetime, largely reducing the load on the Grid infrastructure.\\\\ Given the large amount of submitted jobs and used resources, it becomes essential to store detailed information about their execution to track the behaviour of the system. The DIRAC Account...

  16. DbarD and DD pair production at the LHCb in the parton Reggeization approach

    CERN Document Server

    Karpishkov, A V; Saleev, V A; Shipilova, A V

    2016-01-01

    We study the inclusive DbarD and DD pair production in proton-proton collisions at the LHC at lead- ing order of the parton Reggeization approach endowed with universal scale-depended fragmen- tation functions for c-quark to D-meson and for gluon to D-meson transitions. We have described DbarD and DD distributions in azimuthal angle, as well as transverse momentum, rapidity distance, and invariant mass measured in the region of large rapidity 2 < y < 4 by the LHCb Collabora- tion at the LHC without free parameters. We have used Reggeized amplitudes for the processes RR - gg and RR - c barc which are obtained accordingly to Feynman rules of the L.N. Lipatov effective theory of Reggeized partons, and Kimber-Martin-Ryskin model for unintegrated gluon distribution function in a proton with Martin-Stirling-Thorne-Watt collinear parton distributions as inputs.

  17. Physics with jets in LHCb arXiv

    CERN Document Server

    Cid Vidal, X.

    LHCb, while purpose built for $b-$physics, also functions as a general purpose forward detector, covering the pseudo-rapidity range 2.0 to 5.0. LHCb has performed several measurements including jets, which concern, e.g., QCD, top and Higgs physics. A selection of LHCb results in this area will be presented, focusing on the most recent ones.

  18. 6th implications of LHCb measurements and future prospects

    CERN Document Server

    2016-01-01

    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. Furthermore, part of the talks will be devoted to theoretical and experimental prospects for a possible future LHCb upgrade, targeting an integrated luminosity of 300 fb-1.

  19. 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.

  20. $CPT$ violation searches and prospects for LHCb

    CERN Document Server

    van Tilburg, Jeroen

    2015-01-01

    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...