Searches for Majorana neutrinos in B- decays

(2012)

Authors:

LHCb Collaboration, R Aaij, C Abellan Beteta, 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, S Belogurov, 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, T Bird, 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, M Britsch, T Britton, NH Brook, H Brown, A Büchler-Germann, I Burducea, A Bursche, J Buytaert, S Cadeddu, 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, Ch Cauet, 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, A Comerma-Montells, F Constantin, A Contu, A Cook, M Coombes, G Corti, GA Cowan, R Currie, C D'Ambrosio, P David, PNY 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, L Del Buono, C Deplano, D Derkach, O Deschamps, F Dettori, J Dickens, H Dijkstra, P Diniz Batista, F Domingo Bonal, S Donleavy, F Dordei, A Dosil Suárez, D Dossett, A Dovbnya, F Dupertuis, R Dzhelyadin, A Dziurda, S Easo, U Egede, V Egorychev, S Eidelman, D van Eijk, F Eisele, S Eisenhardt, R Ekelhof, L Eklund, Ch Elsasser, D Elsby, D Esperante Pereira, 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, D Gascon, C Gaspar, R Gauld, 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, E Greening, S Gregson, B Gui, E Gushchin, Yu Guz, T Gys, C Hadjivasiliou, G Haefeli, C Haen, SC Haines, T Hampson, S Hansmann-Menzemer, R Harji, N Harnew, J Harrison, PF Harrison, T Hartmann, J He, V Heijne, K Hennessy, P Henrard, JA Hernando Morata, E van Herwijnen, E Hicks, 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, M Kaballo, S Kandybei, M Karacson, TM Karbach, J Keaveney, IR Kenyon, U Kerzel, T Ketel, A Keune, B Khanji, YM Kim, M Knecht, R Koopman, P Koppenburg, A Kozlinskiy, L Kravchuk, K Kreplin, M Kreps, G Krocker, P Krokovny, F Kruse, K Kruzelecki, M Kucharczyk, T Kvaratskheliya, VN La Thi, D Lacarrere, G Lafferty, A Lai, D Lambert, RW Lambert, E Lanciotti, G Lanfranchi, C Langenbruch, T Latham, C Lazzeroni, 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, J von Loeben, JH Lopes, E Lopez Asamar, N Lopez-March, H Lu, J Luisier, A Mac Raighne, 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, M Meissner, M Merk, J Merkel, R Messi, S Miglioranzi, DA Milanes, M-N Minard, J Molina Rodriguez, S Monteil, D Moran, P Morawski, R Mountain, I Mous, F Muheim, K Müller, R Muresan, B Muryn, B Muster, M Musy, J Mylroie-Smith, P Naik, T Nakada, R Nandakumar, I Nasteva, M Nedos, M Needham, N Neufeld, AD Nguyen, C Nguyen-Mau, M Nicol, V Niess, N Nikitin, A Nomerotski, A Novoselov, A Oblakowska-Mucha, V Obraztsov, S Oggero, S Ogilvy, O Okhrimenko, R Oldeman, M Orlandea, JM Otalora Goicochea, P Owen, K Pal, J Palacios, A Palano, 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, A Phan, E Picatoste Olloqui, B Pie Valls, B Pietrzyk, T Pilař, D Pinci, R Plackett, S Playfer, M Plo Casasus, G Polok, A Poluektov, E Polycarpo, D Popov, B Popovici, C Potterat, A Powell, 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, A Richards, K Rinnert, DA Roa Romero, P Robbe, E Rodrigues, F Rodrigues, P Rodriguez Perez, GJ Rogers, S Roiser, V Romanovsky, M Rosello, J Rouvinet, T Ruf, H Ruiz, G Sabatino, JJ Saborido Silva, N Sagidova, P Sail, B Saitta, C Salzmann, M Sannino, R Santacesaria, C Santamarina Rios, R Santinelli, E Santovetti, M Sapunov, A Sarti, C Satriano, A Satta, M Savrie, D Savrina, P Schaack, M Schiller, S Schleich, M Schlupp, M Schmelling, B Schmidt, O Schneider, A Schopper, M-H Schune, R Schwemmer, B Sciascia, A Sciubba, M Seco, A Semennikov, K Senderowska, I Sepp, N Serra, J Serrano, P Seyfert, M Shapkin, I Shapoval, P Shatalov, Y Shcheglov, T Shears, L Shekhtman, O Shevchenko, V Shevchenko, A Shires, R Silva Coutinho, T Skwarnicki, NA Smith, E 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, 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, N Torr, E Tournefier, S Tourneur, MT Tran, A Tsaregorodtsev, N Tuning, M Ubeda Garcia, A Ukleja, P Urquijo, U Uwer, V Vagnoni, G Valenti, R Vazquez Gomez, P Vazquez Regueiro, S Vecchi, JJ Velthuis, M Veltri, B Viaud, I Videau, X Vilasis-Cardona, J Visniakov, A Vollhardt, D Volyanskyy, D Voong, A Vorobyev, H Voss, S Wandernoth, J Wang, DR Ward, NK Watson, 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 Xing, Z Yang, R Young, O Yushchenko, M Zavertyaev, F Zhang, L Zhang, WC Zhang, Y Zhang, A Zhelezov, L Zhong, E Zverev, A Zvyagin

First observation of the decays B0bar -->D+ K- pi+ pi- and B- --> D0 K- pi+ pi-

(2012)

Authors:

LHCb Collaboration, R Aaij, C Abellan Beteta, 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, S Belogurov, 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, T Bird, 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, M Britsch, T Britton, NH Brook, H Brown, A Büchler-Germann, I Burducea, A Bursche, J Buytaert, S Cadeddu, 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, Ch Cauet, 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, A Comerma-Montells, F Constantin, A Contu, A Cook, M Coombes, G Corti, GA Cowan, R Currie, C D'Ambrosio, P David, PNY 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, L Del Buono, C Deplano, D Derkach, O Deschamps, F Dettori, J Dickens, H Dijkstra, P Diniz Batista, F Domingo Bonal, S Donleavy, F Dordei, A Dosil Suárez, D Dossett, A Dovbnya, F Dupertuis, R Dzhelyadin, A Dziurda, S Easo, U Egede, V Egorychev, S Eidelman, D van Eijk, F Eisele, S Eisenhardt, R Ekelhof, L Eklund, Ch Elsasser, D Elsby, 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, D Gascon, 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, E Greening, 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, T Hartmann, J He, V Heijne, K Hennessy, P Henrard, JA Hernando Morata, E van Herwijnen, E Hicks, 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, M Kaballo, S Kandybei, M Karacson, TM Karbach, J Keaveney, IR Kenyon, U Kerzel, T Ketel, A Keune, B Khanji, YM Kim, M Knecht, R Koopman, P Koppenburg, A Kozlinskiy, L Kravchuk, K Kreplin, M Kreps, G Krocker, P Krokovny, F Kruse, K Kruzelecki, M Kucharczyk, T Kvaratskheliya, VN La Thi, D Lacarrere, G Lafferty, A Lai, D Lambert, RW Lambert, E Lanciotti, G Lanfranchi, C Langenbruch, T Latham, C Lazzeroni, 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, J von Loeben, JH Lopes, E Lopez Asamar, N Lopez-March, H Lu, J Luisier, A Mac Raighne, 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, M Meissner, M Merk, J Merkel, R Messi, S Miglioranzi, DA Milanes, M-N Minard, J Molina Rodriguez, S Monteil, D Moran, P Morawski, R Mountain, I Mous, F Muheim, K Müller, R Muresan, B Muryn, B Muster, M Musy, J Mylroie-Smith, P Naik, T Nakada, R Nandakumar, I Nasteva, M Nedos, M Needham, N Neufeld, C Nguyen-Mau, M Nicol, V Niess, N Nikitin, A Nomerotski, A Novoselov, A Oblakowska-Mucha, V Obraztsov, S Oggero, S Ogilvy, O Okhrimenko, R Oldeman, M Orlandea, JM Otalora Goicochea, P Owen, K Pal, J Palacios, A Palano, 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, A Phan, E Picatoste Olloqui, B Pie Valls, B Pietrzyk, T Pilař, D Pinci, R Plackett, S Playfer, M Plo Casasus, G Polok, A Poluektov, E Polycarpo, D Popov, B Popovici, C Potterat, A Powell, 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, M Rosello, J Rouvinet, T Ruf, H Ruiz, G Sabatino, JJ Saborido Silva, N Sagidova, P Sail, B Saitta, C Salzmann, M Sannino, R Santacesaria, C Santamarina Rios, R Santinelli, E Santovetti, M Sapunov, A Sarti, C Satriano, A Satta, M Savrie, D Savrina, P Schaack, M Schiller, S Schleich, M Schlupp, M Schmelling, B Schmidt, O Schneider, A Schopper, M-H Schune, R Schwemmer, B Sciascia, A Sciubba, M Seco, A Semennikov, K Senderowska, I Sepp, N Serra, J Serrano, P Seyfert, M Shapkin, I Shapoval, P Shatalov, Y Shcheglov, T Shears, L Shekhtman, O Shevchenko, V Shevchenko, A Shires, R Silva Coutinho, T Skwarnicki, AC Smith, NA Smith, E 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, 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, N Torr, E Tournefier, MT Tran, A Tsaregorodtsev, N Tuning, M Ubeda Garcia, A Ukleja, P Urquijo, U Uwer, V Vagnoni, G Valenti, R Vazquez Gomez, P Vazquez Regueiro, S Vecchi, JJ Velthuis, M Veltri, B Viaud, I Videau, X Vilasis-Cardona, J Visniakov, A Vollhardt, D Volyanskyy, D Voong, A Vorobyev, H Voss, S Wandernoth, J Wang, DR Ward, NK Watson, 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 Xing, Z Yang, R Young, O Yushchenko, M Zavertyaev, F Zhang, L Zhang, WC Zhang, Y Zhang, A Zhelezov, L Zhong, E Zverev, A Zvyagin

Observation of J/ψ-pair production in pp collisions at √s=7 TeV

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 707:1 (2012) 52-59

Authors:

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, T Bauer, A Bay, I Bediaga, K Belous, I Belyaev, E Ben-Haim, M Benayoun, G Bencivenni, S Benson, J Benton, R Bernet, MO 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, P Charpentier, N Chiapolini, K Ciba, X Cid Vidal, G Ciezarek, PEL Clarke

Abstract:

The production of J/ψ 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 J/ψ in the rapidity range 2

A multi-cohort study of polymorphisms in the GH/IGF axis and physical capability: The HALCyon programme

PLoS ONE 7:1 (2012)

Authors:

T Alfred, Y Ben-Shlomo, R Cooper, R Hardy, C Cooper, IJ Deary, TR Gaunt, D Gunnell, SE Harris, M Kumari, RM Martin, AA Sayer, JM Starr, D Kuh, INM Day

Abstract:

Background: Low muscle mass and function have been associated with poorer indicators of physical capability in older people, which are in-turn associated with increased mortality rates. The growth hormone/insulin-like growth factor (GH/IGF) axis is involved in muscle function and genetic variants in genes in the axis may influence measures of physical capability. Methods: As part of the Healthy Ageing across the Life Course (HALCyon) programme, men and women from seven UK cohorts aged between 52 and 90 years old were genotyped for six polymorphisms: rs35767 (IGF1), rs7127900 (IGF2), rs2854744 (IGFBP3), rs2943641 (IRS1), rs2665802 (GH1) and the exon-3 deletion of GHR. The polymorphisms have previously been robustly associated with age-related traits or are potentially functional. Meta-analysis was used to pool within-study genotypic effects of the associations between the polymorphisms and four measures of physical capability: grip strength, timed walk or get up and go, chair rises and standing balance. Results: Few important associations were observed among the several tests. We found evidence that rs2665802 in GH1 was associated with inability to balance for 5 s (pooled odds ratio per minor allele = 0.90, 95% CI: 0.82-0.98, p-value = 0.01, n = 10,748), after adjusting for age and sex. We found no evidence for other associations between the polymorphisms and physical capability traits. Conclusion: Our findings do not provide evidence for a substantial influence of these common polymorphisms in the GH/IGF axis on objectively measured physical capability levels in older adults. © 2012 Alfred et al.

Absolute luminosity measurements with the LHCb detector at the LHC

Journal of Instrumentation 7:1 (2012)

Authors:

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, T 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, T.j.v. 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, P Charpentier, N Chiapolini, K Ciba, X Cid Vidal, G Ciezarek, P.e.l. Clarke

Abstract:

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. Using data taken in 2010, 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 overal precision of 3.5% in the absolute luminosity determination is reached. The techniques used to transport the absolute luminosity calibration to the full 2010 data-taking period are presented. © 2012 CERN.