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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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Constraints on brittle field exhumation of the Everest-Makalu section of the Greater Himalayan Sequence: Implications for models of crustal flow

Tectonics 31:3 (2012)

Authors:

MJ Streule, A Carter, MP Searle, JM Cottle

Abstract:

New apatite and zircon fission track (FT) data from the summit slopes of Everest and along the Barun, Arun, Dudh Kosi, and Kangshung valleys that drain the Everest and Makalu massifs cover a vertical sample transect of almost 8000m of the Eastern Nepal Greater Himalayan Sequence (GHS). Apatite FT ages range from 0.9±0.3Ma to 3.1±0.3Ma in the GHS with ages increasing systematically with elevation. Apatite FT ages in the Everest Series and summit Ordovician limestones are much older, up to 30.5±5.1Ma. Zircon FT ages from the GHS range from 3.8±0.4Ma to 16.3±0.8Ma. The brittle exhumation rates calculated from these data show the GHS was exhumed, since ∼9Ma, at an average rate of 1.0±0.2mm/a. Pliocene exhumation rates are higher at 1.7±0.3mm/a. These values are not significantly different from the estimate of ductile exhumation rates of 1.8mm/a recorded by metamorphic minerals undergoing decompression between 18.7 and 15.6Ma but are well below the values (up to 10mm/a) used by thermomechanical models for ductile channel flow in the GHS. If representative of the GHS these models will therefore require further tuning. Higher exhumation rates in the Pliocene have also been observed in other parts of the Himalaya and points to a regional cause, likely increased erosion due to the onset of late Pliocene-Pleistocene glaciation of the high Himalaya. Copyright © 2012 by the American Geophysical Union.
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