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Measurement of ϒ production in pp collisions at √s =7 TeV

European Physical Journal C 72:6 (2012)

Authors:

R Aaij, CA Beteta, B Adeva, M Adinolfi, C Adrover, A Affolder, Z Ajaltouni, J Albrecht, F Alessio, M Alexander, G Alkhazov, PA Cartelle, AA Alves, S Amato, Y Amhis, J Anderson, RB Appleby, OA 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, S Belogurov, 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, 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, K De Bruyn, A Büchler-Germann, I Burducea, A Bursche, J Buytaert, S Cadeddu, O Callot, M Calvi, MC Gomez, A Camboni, P Campana, A Carbone, G Carboni, R Cardinale, A Cardini, L Carson, KC Akiba, G Casse, M Cattaneo, C Cauet, M Charles, P Charpentier, N Chiapolini, K Ciba

Abstract:

The production of ϒ (1S), ϒ (2S) and ϒ (3S) mesons in proton-proton collisions at the centre-of-mass energy of √s = 7 TeV is studied with the LHCb detector. The analysis is based on a data sample of 25 pb−1 collected at the Large Hadron Collider. The ϒ mesons are reconstructed in the decay mode ϒ →μ + μ − and the signal yields are extracted from a fit to the μ + μ − invariant mass distributions. The differential production cross-sections times dimuon branching fractions are measured as a function of the ϒ transverse momentum pT and rapidity y, over the range pT < 15 GeV/c and 2.0+ μ −) = 2.29 ± 0.01 ± 0.10+0.19 −0.37 nb, σ(pp→ϒ (2S)X)×B(ϒ (2S)→μ + μ −) = 0.562±0.007±0.023+0.048 −0.092 nb, σ(pp→ϒ (3S)X)×B(ϒ (3S)→μ + μ −) = 0.283±0.005±0.012+0.025 −0.048 nb, where the first uncertainty is statistical, the second systematic and the third is due to the unknown polarisation of the three ϒ states.
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Opposite-side flavour tagging of B mesons at the LHCb experiment

European Physical Journal C 72:6 (2012)

Authors:

R Aaij, CA Beteta, B Adeva, M Adinolfi, C Adrover, A Affolder, Z Ajaltouni, J Albrecht, F Alessio, M Alexander, G Alkhazov, PA Cartelle, AA Alves, S Amato, Y Amhis, J Anderson, RB Appleby, OA 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, S Belogurov, 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, 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, K De Bruyn, A Büchler-Germann, I Burducea, A Bursche, J Buytaert, S Cadeddu, O Callot, M Calvi, MC Gomez, A Camboni, P Campana, A Carbone, G Carboni, R Cardinale, A Cardini, L Carson, KC Akiba, G Casse, M Cattaneo, C Cauet, M Charles, P Charpentier, N Chiapolini, K Ciba

Abstract:

The calibration and performance of the opposites-ide flavour tagging algorithms used for the measurements of time-dependent asymmetries at the LHCb experiment are described. The algorithms have been developed using simulated events and optimized and calibrated with B + → J/ψ K + , B 0 →J/ψK* 0 and B 0 →D* − μ + ν μ decay modes with 0.37 fb −1 of data collected in pp collisions at √s = 7 TeV during the 2011 physics run. The opposite-side tagging power is determined in the B + → J/ψ K + channel to be (2.10 ± 0.08 ± 0.24) %, where the first uncertainty is statistical and the second is systematic.
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Observation of CP violation in B ±→DK ± decays

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 712:3 (2012) 203-212

Authors:

R Aaij, C Abellan Beteta, B Adeva, M Adinolfi, C Adrover, A Affolder, Z Ajaltouni, J Albrecht, F Alessio, M Alexander, S Ali, G Alkhazov, P Alvarez Cartelle, AA Alves, S Amato, Y Amhis, J Anderson, RB Appleby, O Aquines Gutierrez, F Archilli, F Archilli, A Artamonov, M Artuso, M Artuso, E Aslanides, G Auriemma, S Bachmann, JJ Back, V Balagura, V Balagura, W Baldini, RJ Barlow, C Barschel, S Barsuk, W Barter, A Bates, C Bauer, T Bauer, A Bay, I Bediaga, S Belogurov, 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, 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, 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, K de Bruyn, A Büchler-Germann, I Burducea, A Bursche, J Buytaert, S Cadeddu, O Callot, M Calvi, M Calvo Gomez, A Camboni, P Campana, P Campana, A Carbone, G Carboni, R Cardinale, R Cardinale, A Cardini, L Carson, K Carvalho Akiba, G Casse, M Cattaneo

Abstract:

An analysis of B ±→DK ± and B ±→Dπ ± decays is presented where the D meson is reconstructed in the two-body final states: K ±π ∓, K +K - and π +π -. Using 1.0 fb -1 of s=7TeV pp collisions, measurements of several observables are made including the first observation of the suppressed mode B±→[π±K∓]DK± CP violation in B ±→DK ± decays is observed with 5.8σ significance. © 2012 CERN.
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Observation of CP violation in B±→DK± decays

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 712:3 (2012) 203-212

Authors:

R Aaij, C Abellan Beteta, B Adeva, M Adinolfi, C Adrover, A Affolder, Z Ajaltouni, J Albrecht, F Alessio, M Alexander, S Ali, G Alkhazov, P Alvarez Cartelle, AA Alves, S Amato, Y Amhis, J Anderson, RB Appleby, O Aquines Gutierrez, F Archilli, A Artamonov, M Artuso, E Aslanides, G Auriemma, S Bachmann, JJ Back, V Balagura, W Baldini, RJ Barlow, C Barschel, S Barsuk, W Barter, A Bates, C Bauer, T Bauer, A Bay, I Bediaga, S Belogurov, 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, 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, K de Bruyn, 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, C Cauet, M Charles, P Charpentier, N Chiapolini, K Ciba, X Cid Vidal

Abstract:

An analysis of B±→DK± and B±→Dπ± decays is presented where the D meson is reconstructed in the two-body final states: K±π∓, K+K- and π+π-. Using 1.0 fb-1 of s=7TeV pp collisions, measurements of several observables are made including the first observation of the suppressed mode B±→[π±K∓]DK± CP violation in B±→DK± decays is observed with 5.8σ significance. © 2012 CERN.
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Strong constraints on the rare decays Bs0→μ +μ - and B0→μ +μ -

Physical Review Letters 108:23 (2012)

Authors:

R Aaij, C Abellan Beteta, A Adametz, B Adeva, M Adinolfi, C Adrover, A Affolder, Z Ajaltouni, J Albrecht, F Alessio, M Alexander, S Ali, G Alkhazov, P Alvarez Cartelle, AA Alves, S Amato, Y Amhis, J Anderson, RB Appleby, O Aquines Gutierrez, F Archilli, A Artamonov, M Artuso, E Aslanides, G Auriemma, S Bachmann, JJ Back, V Balagura, W Baldini, RJ Barlow, C Barschel, S Barsuk, W Barter, A Bates, C Bauer, T Bauer, A Bay, J Beddow, I Bediaga, S Belogurov, 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, 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, C Cauet, M Charles, P Charpentier, N Chiapolini, M Chrzaszcz

Abstract:

A search for Bs0→μ +μ - and B0→μ +μ - decays is performed using 1.0fb -1 of pp collision data collected at √s=7TeV with the LHCb experiment at the Large Hadron Collider. For both decays, the number of observed events is consistent with expectation from background and standard model signal predictions. Upper limits on the branching fractions are determined to be B(Bs0→μ +μ -)<4.5(3.8)×10 -9 and B(B0→μ +μ -)<1.0(0.81)×10 -9 at 95% (90%) confidence level. © 2012 CERN.
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