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

European Physical Journal C 72:6 (2012) 1-12

Authors:

R Aaij, R Aaij, CA Beteta, CA Beteta, B Adeva, B Adeva, M Adinolfi, M Adinolfi, C Adrover, C Adrover, A Affolder, A Affolder, Z Ajaltouni, Z Ajaltouni, J Albrecht, J Albrecht, F Alessio, F Alessio, M Alexander, M Alexander, G Alkhazov, G Alkhazov, P Alvarez Cartelle, P Alvarez Cartelle, AA Alves, AA Alves, S Amato, S Amato, Y Amhis, Y Amhis, J Anderson, J Anderson, RB Appleby, RB Appleby, O Aquines Gutierrez, O Aquines Gutierrez, F Archilli, F Archilli, F Archilli, L Arrabito, L Arrabito, A Artamonov, A Artamonov, M Artuso, M Artuso, M Artuso, E Aslanides, E Aslanides, G Auriemma, G Auriemma, S Bachmann, S Bachmann, JJ Back, JJ Back, DS Bailey, DS Bailey, V Balagura, V Balagura, V Balagura, W Baldini, W Baldini, RJ Barlow, RJ Barlow, C Barschel, C Barschel, S Barsuk, S Barsuk, W Barter, W Barter, A Bates, A Bates, C Bauer, C Bauer, T Bauer, T Bauer, A Bay, A Bay, I Bediaga, I Bediaga, S Belogurov, S Belogurov, K Belous, K Belous, I Belyaev, I Belyaev, E Ben-Haim, E Ben-Haim, M Benayoun, M Benayoun, G Bencivenni, G Bencivenni, S Benson, S Benson, J Benton, J Benton, R Bernet, R Bernet, MO Bettler, MO Bettler, M van Beuzekom

Abstract:

The production of Υ{hooked}(1S), Υ{hooked}(2S) and Υ{hooked}(3S) mesons in proton-proton collisions at the centre-of-mass energy of √ s = 7TeV 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{hooked} mesons are reconstructed in the decay mode Υ{hooked}→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{hooked} transverse momentum pT and rapidity y, over the range pT<15 GeV/c and 2. 0
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Opposite-side flavour tagging of B mesons at the LHCb experiment

European Physical Journal C 72:6 (2012) 1-16

Authors:

R Aaij, R Aaij, CA Beteta, CA Beteta, B Adeva, B Adeva, M Adinolfi, M Adinolfi, C Adrover, C Adrover, A Affolder, A Affolder, Z Ajaltouni, Z Ajaltouni, J Albrecht, J Albrecht, F Alessio, F Alessio, M Alexander, M Alexander, G Alkhazov, G Alkhazov, PA Cartelle, PA Cartelle, AA Alves, AA Alves, S Amato, S Amato, Y Amhis, Y Amhis, J Anderson, J Anderson, RB Appleby, RB Appleby, OA Gutierrez, OA Gutierrez, F Archilli, F Archilli, F Archilli, L Arrabito, L Arrabito, A Artamonov, A Artamonov, M Artuso, M Artuso, M Artuso, E Aslanides, E Aslanides, G Auriemma, G Auriemma, S Bachmann, S Bachmann, JJ Back, JJ Back, DS Bailey, DS Bailey, V Balagura, V Balagura, V Balagura, W Baldini, W Baldini, RJ Barlow, RJ Barlow, C Barschel, C Barschel, S Barsuk, S Barsuk, W Barter, W Barter, A Bates, A Bates, C Bauer, C Bauer, T Bauer, T Bauer, A Bay, A Bay, I Bediaga, I Bediaga, S Belogurov, S Belogurov, K Belous, K Belous, I Belyaev, I Belyaev, E Ben-Haim, E Ben-Haim, M Benayoun, M Benayoun, G Bencivenni, G Bencivenni, S Benson, S Benson, J Benton, J Benton, R Bernet, R Bernet, MO Bettler, MO Bettler, M van Beuzekom

Abstract:

The calibration and performance of the opposite-side 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/ψK+, B0→J/ψK*0 and B0→D*-μ+νμ 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/ψK+ channel to be (2. 10±0. 08±0. 24) %, where the first uncertainty is statistical and the second is systematic. © 2012 CERN for the benefit of the LHCb collaboration.
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Studies of the decays D0→KS0K-π+ and D0→KS0K+π-

Physical Review D - Particles, Fields, Gravitation and Cosmology 85:9 (2012)

Authors:

J Insler, H Muramatsu, CS Park, LJ Pearson, EH Thorndike, S Ricciardi, C Thomas, M Artuso, S Blusk, R Mountain, T Skwarnicki, S Stone, JC Wang, LM Zhang, G Bonvicini, D Cinabro, MJ Smith, P Zhou, T Gershon, P Naik, J Rademacker, KW Edwards, K Randrianarivony, RA Briere, H Vogel, PUE Onyisi, JL Rosner, JP Alexander, DG Cassel, S Das, R Ehrlich, L Gibbons, SW Gray, DL Hartill, 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, D Besson, TK Pedlar, D Cronin-Hennessy, J Hietala, S Dobbs, Z Metreveli, KK Seth, A Tomaradze, T Xiao, D Johnson, S Malde, L Martin, A Powell, G Wilkinson, DM Asner, G Tatishvili, JY Ge, DH Miller, IPJ Shipsey, B Xin, GS Adams, J Napolitano, KM Ecklund

Abstract:

The first measurements of the coherence factor RKS0Kπ and the average strong-phase difference δDKS0Kπ in D0→KS0K ∓π± decays are reported. These parameters can be used to improve the determination of the unitary triangle angle γ in B-→D∼K- decays, where D∼ is either a D0 or a D̄0 meson decaying to the same final state, and also in studies of charm mixing. The measurements of the coherence factor and strong-phase difference are made using quantum-correlated, fully reconstructed D0D̄0 pairs produced in e+e- collisions at the ψ(3770) resonance. The measured values are RKS0Kπ=0. 73±0.08 and δDKS0Kπ=(8.3±15.2)° for an unrestricted kinematic region and RK*K=1.00±0.16 and δDK *K=(26.5±15.8)° for a region where the combined KS0π± invariant mass is within 100MeV/c2 of the K *(892)± mass. These results indicate a significant level of coherence in the decay. In addition, isobar models are presented for the two decays, which show the dominance of the K *(892)± resonance. The branching ratio B(D0→KS0K+π-)/B(D0→KS0K -π+) is determined to be 0.592±0.044(stat) ±0.018(syst), which is more precise than previous measurements. © 2012 American Physical Society.
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