R & D status for the LHCb TORCH project

Journal of Instrumentation IOP Publishing 6:10 (2011) c10004-c10004

Measurements of the Branching fractions for $B_(s) -> D_(s)\pi\pi\pi$ and $\Lambda_b^0 -> \Lambda_c^+\pi\pi\pi$

(2011)

Authors:

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

Measurements of the Branching fractions for $B_(s) -> D_(s)πππ$ and $Λ_b^0 -> Λ_c^+πππ$

ArXiv 1109.6831 (2011)

Authors:

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

Abstract:

Branching fractions of the decays $H_b\to H_c\pi^-\pi^+\pi^-$ relative to $H_b\to H_c\pi^-$ are presented, where $H_b$ ($H_c$) represents B^0-bar($D^+$), $B^-$ ($D^0$), B_s^0-bar ($D_s^+$) and $\Lambda_b^0$ ($\Lambda_c^+$). The measurements are performed with the LHCb detector using 35${\rm pb^{-1}}$ of data collected at $\sqrt{s}=7$ TeV. The ratios of branching fractions are measured to be B(B^0-bar -> D^+\pi^-\pi^+\pi^-)/ B(B^0-bar -> D^+\pi^-) = 2.38\pm0.11\pm0.21 B(B^- -> D^0\pi^-\pi^+\pi^-) / B(B^- -> D^0\pi^-) = 1.27\pm0.06\pm0.11 B(B_s^0-bar -> D_s^+\pi^-\pi^+\pi^-) / B(B_s^0-bar -> D_s^+\pi^-) = 2.01\pm0.37\pm0.20 B(\Lambda_b^0->\Lambda_c^+\pi^-\pi^+\pi^-) / B(\Lambda_b^0 -> \Lambda_c^+\pi^-) = 1.43\pm0.16\pm0.13. We also report measurements of partial decay rates of these decays to excited charm hadrons. These results are of comparable or higher precision than existing measurements.

Amplitude analyses of the decays chi_c1 -> eta pi+ pi- and chi_c1 -> eta' pi+ pi-

(2011)

Authors:

CLEO Collaboration, GS Adams, J Napolitano, KM Ecklund, J Insler, H Muramatsu, CS Park, LJ Pearson, EH Thorndike, S Ricciardi, C Thomas, M Artuso, S Blusk, R Mountain, T Skwarnicki, S Stone, LM Zhang, G Bonvicini, D Cinabro, A Lincoln, MJ Smith, P Zhou, J Zhu, P Naik, J Rademacker, DM Asner, KW Edwards, K Randrianarivony, G Tatishvili, RA Briere, H Vogel, PUE Onyisi, JL Rosner, JP Alexander, DG Cassel, S Das, R Ehrlich, L Gibbons, SW Gray, DL Hartill, BK Heltsley, DL Kreinick, VE Kuznetsov, JR Patterson, D Peterson, D Riley, A Ryd, AJ Sadoff, X Shi, WM Sun, J Yelton, P Rubin, N Lowrey, S Mehrabyan, M Selen, J Wiss, J Libby, M Kornicer, RE Mitchell, MR Shepherd, A Szczepaniak, D Besson, TK Pedlar, D Cronin-Hennessy, J Hietala, S Dobbs, Z Metreveli, KK Seth, A Tomaradze, T Xiao, L Martin, A Powell, G Wilkinson, JY Ge, DH Miller, IPJ Shipsey, B Xin

Observation of $J/ψ$ pair production in pp collisions at $\sqrt{s}=7 TeV$

ArXiv 1109.0963 (2011)

Authors:

LHCb Collaboration, R Aaij, B Adeva, M Adinolfi, C Adrover, A Affolder, Z Ajaltouni, J Albrecht, F Alessio, M Alexander, G Alkhazov, P Alvarez Cartelle, AA Alves Jr, S Amato, Y Amhis, J Anderson, RB Appleby, O Aquines Gutierrez, F Archilli, L Arrabito, A Artamonov, M Artuso, E Aslanides, G Auriemma, S Bachmann, JJ Back, DS Bailey, V Balagura, W Baldini, RJ Barlow, C Barschel, S Barsuk, W Barter, A Bates, C Bauer, Th Bauer, A Bay, I Bediaga, K Belous, I Belyaev, E Ben-Haim, M Benayoun, G Bencivenni, S Benson, J Benton, R Bernet, M-O Bettler, M van Beuzekom, A Bien, S Bifani, A Bizzeti, PM Bjørnstad, T Blake, F Blanc, C Blanks, J Blouw, S Blusk, A Bobrov, V Bocci, A Bondar, N Bondar, W Bonivento, S Borghi, A Borgia, TJV Bowcock, C Bozzi, T Brambach, J van den Brand, J Bressieux, D Brett, S Brisbane, M Britsch, T Britton, NH Brook, H Brown, A Büchler-Germann, I Burducea, A Bursche, J Buytaert, S Cadeddu, JM Caicedo Carvajal, O Callot, M Calvi, M Calvo Gomez, A Camboni, P Campana, A Carbone, G Carboni, R Cardinale, A Cardini, L Carson, K Carvalho Akiba, G Casse, M Cattaneo, M Charles, Ph Charpentier, N Chiapolini, K Ciba, X Cid Vidal, G Ciezarek, PEL Clarke, M Clemencic, HV Cliff, J Closier, C Coca, V Coco, J Cogan, P Collins, F Constantin, G Conti, A Contu, A Cook, M Coombes, G Corti, GA Cowan, R Currie, B D'Almagne, C D'Ambrosio, P David, I De Bonis, S De Capua, M De Cian, F De Lorenzi, JM De Miranda, L De Paula, P De Simone, D Decamp, M Deckenhoff, H Degaudenzi, M Deissenroth, L Del Buono, C Deplano, O Deschamps, F Dettori, J Dickens, H Dijkstra, P Diniz Batista, S Donleavy, A Dosil Suárez, D Dossett, A Dovbnya, F Dupertuis, R Dzhelyadin, C Eames, S Easo, U Egede, V Egorychev, S Eidelman, D van Eijk, F Eisele, S Eisenhardt, R Ekelhof, L Eklund, Ch Elsasser, DG d'Enterria, D Esperante Pereira, L Estève, A Falabella, E Fanchini, C Färber, G Fardell, C Farinelli, S Farry, V Fave, V Fernandez Albor, M Ferro-Luzzi, S Filippov, C Fitzpatrick, M Fontana, F Fontanelli, R Forty, M Frank, C Frei, M Frosini, S Furcas, A Gallas Torreira, D Galli, M Gandelman, P Gandini, Y Gao, J-C Garnier, J Garofoli, J Garra Tico, L Garrido, C Gaspar, N Gauvin, M Gersabeck, T Gershon, Ph Ghez, V Gibson, VV Gligorov, C Göbel, D Golubkov, A Golutvin, A Gomes, H Gordon, M Grabalosa Gándara, R Graciani Diaz, LA Granado Cardoso, E Graugés, G Graziani, A Grecu, S Gregson, B Gui, E Gushchin, Yu Guz, T Gys, G Haefeli, C Haen, SC Haines, T Hampson, S Hansmann-Menzemer, R Harji, N Harnew, J Harrison, PF Harrison, J He, V Heijne, K Hennessy, P Henrard, JA Hernando Morata, E van Herwijnen, E Hicks, W Hofmann, K Holubyev, P Hopchev, W Hulsbergen, P Hunt, T Huse, RS Huston, D Hutchcroft, D Hynds, V Iakovenko, P Ilten, J Imong, R Jacobsson, A Jaeger, M Jahjah Hussein, E Jans, F Jansen, P Jaton, B Jean-Marie, F Jing, M John, D Johnson, CR Jones, B Jost, S Kandybei, M Karacson, TM Karbach, J Keaveney, U Kerzel, T Ketel, A Keune, B Khanji, YM Kim, M Knecht, S Koblitz, P Koppenburg, A Kozlinskiy, L Kravchuk, K Kreplin, M Kreps, G Krocker, P Krokovny, F Kruse, K Kruzelecki, M Kucharczyk, S Kukulak, R Kumar, T Kvaratskheliya, VN La Thi, D Lacarrere, G Lafferty, A Lai, D Lambert, RW Lambert, E Lanciotti, G Lanfranchi, C Langenbruch, T Latham, R Le Gac, J van Leerdam, J-P Lees, R Lefèvre, A Leflat, J Lefrançois, O Leroy, T Lesiak, L Li, L Li Gioi, M Lieng, M Liles, R Lindner, C Linn, B Liu, G Liu, JH Lopes, E Lopez Asamar, N Lopez-March, J Luisier, F Machefert, IV Machikhiliyan, F Maciuc, O Maev, J Magnin, S Malde, RMD Mamunur, G Manca, G Mancinelli, N Mangiafave, U Marconi, R Märki, J Marks, G Martellotti, A Martens, L Martin, A Martín Sánchez, D Martinez Santos, A Massafferri, Z Mathe, C Matteuzzi, M Matveev, E Maurice, B Maynard, A Mazurov, G McGregor, R McNulty, C Mclean, M Meissner, M Merk, J Merkel, R Messi, S Miglioranzi, DA Milanes, M-N Minard, S Monteil, D Moran, P Morawski, R Mountain, I Mous, F Muheim, K Müller, R Muresan, B Muryn, M Musy, J Mylroie-Smith, P 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Abstract:

The production of $J/\psi$ pairs in proton-proton collisions at a centre-of-mass energy of 7 TeV has been observed using an integrated luminosity of $37.5 pb^{-1}$ collected with the LHCb detector. The production cross-section for pairs with both \jpsi in the rapidity range $2