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First measurement of time-dependent CP violation in B0 → K+K- decays

Journal of High Energy Physics 2013:10 (2013)

Authors:

R Aaij, B Adeva, M Adinolfi, C Adrover, A Affolder, Z Ajaltouni, J Albrecht, F Alessio, M Alexander, S Ali, G Alkhazov, PA Cartelle, AA Alves, S Amato, S Amerio, Y Amhis, L Anderlini, J Anderson, R Andreassen, JE Andrews, RB Appleby, OA Gutierrez, F Archilli, A Artamonov, M Artuso, E Aslanides, G Auriemma, M Baalouch, S Bachmann, JJ Back, C Baesso, V Balagura, W Baldini, RJ Barlow, C Barschel, S Barsuk, W Barter, T Bauer, A Bay, J Beddow, F Bedeschi, I Bediaga, S Belogurov, K Belous, I Belyaev, E Ben-Hai, G Bencivenni, S Benson, J Benton, A Berezhnoy, R Bernet, MO Bettler, MV Beuzeko, A Bien, S Bifani, T Bird, A Bizzeti, PM Bjørnstad, T Blake, F Blanc, J Blouw, S Blusk, V Bocci, A Bondar, N Bondar, W Bonivento, S Borghic, A Borgia, TJV Bowcock, E Bowen, C Bozzi, T Brambach, JVD Brand, J Bressieux, D Brett, M Britsch, T Britton, NH Brook, H Brown, I Burducea, A Bursche, G Busetto, J Buytaert, S Cadeddu, O Callot, M Calvi, MC Gomez, A Camboni, P Campana, DC Perez, A Carbone, G Carboni, R Cardinale, A Cardini, H Carranza-Mejia, L Carson, KC Akiba, G Casse, LC Garcia, M Cattaneo

Abstract:

Direct and mixing-induced CP-violating asymmetries in B0s → K+K- decays are measured for the first time using a data sample of pp collisions, corresponding to an integrated luminosity of 1.0 fb-1, collected with the LHCb detector at a centre-of-mass energy of 7TeV. The results are CKK = 0.14 ± 0.11 ± 0.03 and SKK = 0.30 ± 0.12 ± 0.04, where the first uncertainties are statistical and the second systematic. The corresponding quantities are also determined for B0→π +π- decays to be Cππ = -0.38±0.15±0.02 and Sππ = -0.71±0. 13±0.02, in good agreement with existing measurements.
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First observation of the decay Bc+to → J/ψ K+

Journal of High Energy Physics 2013:9 (2013)

Authors:

R Aaij, CA Beteta, B Adeva, M Adinolfi, C Adrover, A Affolder, Z Ajaltouni, J Albrecht, F Alessio, M Alexander, S Ali, G Alkhazov, PA Cartelle, AA Alves, S Amato, S Amerio, Y Amhis, L Anderlini, J Anderson, R Andreassen, RB Appleby, OA Gutierrez, F Archilli, A Artamonov, M Artuso, E Aslanides, G Auriemma, S Bachmann, JJ Back, C Baesso, V Balagura, W Baldini, RJ Barlow, C Barschel, S Barsuk, W Barter, T Bauer, A Bay, J Beddow, F Bedeschi, I Bediaga, S Belogurov, K Belous, I Belyaev, E Ben-Haim, G Bencivenni, S Benson, J Benton, A Berezhnoy, R Bernet, MO Bettler, M Van Beuzekom, A Bien, S Bifani, T Bird, A Bizzeti, PM Bjørnstad, T Blake, F Blanc, J Blouw, S Blusk, V Bocci, A Bondar, N Bondar, W Bonivento, S Borghi, A Borgia, TJV Bowcock, E Bowen, C Bozzi, T Brambach, J Van Den Brand, J Bressieux, D Brett, M Britsch, T Britton, NH Brook, H Brown, I Burducea, A Bursche, G Busetto, J Buytaert, S Cadeddu, O Callot, M Calvi, MC Gomez, A Camboni, P Campana, DC Perez, A Carbone, G Carboni, R Cardinale, A Cardini, H Carranza-Mejia, L Carson, KC Akiba, G Casse, LC Garcia, M Cattaneo, C Cauet

Abstract:

The decay Bc+to → J/ψ K+ is observed for the first time using a data sample, corresponding to an integrated luminosity of 1.0 fb-1, collected by the LHCb experiment in pp collisions at a centre-of-mass energy of 7 TeV. A yield of 46 ± 12 events is reported, with a significance of 5.0 standard deviations. The ratio of the branching fraction of Bc+to → J/ψ K+ to that of Bc+to → J/ψ K+ is measured to be 0.069 ± 0.019 ± 0.005, where the first uncertainty is statistical and the second is systematic. © 2013 Cern for the benefit of the LHCb collaboration.
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First observation of the decay Bs0 → φ K̄*0

Journal of High Energy Physics 2013:11 (2013)

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, S Amerio, Y Amhis, L Anderlini, J Anderson, R Andreassen, RB Appleby, O Aquines Gutierrez, F Archilli, A Artamonov, M Artuso, E Aslanides, G Auriemma, S Bachmann, JJ Back, C Baesso, V Balagura, W Baldini, RJ Barlow, C Barschel, S Barsuk, W Barter, T Bauer, A Bay, J Beddow, F Bedeschi, I Bediaga, S Belogurov, K Belous, I Belyaev, E Ben-Haim, M Benayoun, G Bencivenni, S Benson, J Benton, A Berezhnoy, R Bernet, MO Bettler, M Van Beuzekom, A Bien, S Bifani, T Bird, A Bizzeti, PM Bjørnstad, T Blake, F Blanc, J Blouw, S Blusk, V Bocci, A Bondar, N Bondar, W Bonivento, S Borghi, A Borgia, TJV Bowcock, E Bowen, C Bozzi, T Brambach, J Van Den Brand, J Bressieux, D Brett, M Britsch, T Britton, NH Brook, H Brown, I Burducea, A Bursche, G Busetto, J Buytaert, S Cadeddu, O Callot, M Calvi, M Calvo Gomez, A Camboni, P Campana, D Campora Perez, A Carbone, G Carboni, R Cardinale, A Cardini, H Carranza-Mejia, L Carson, K Carvalho Akiba, G Casse, L Castillo Garcia, M Cattaneo

Abstract:

The first observation of the decay Bs0 → φK̄*0 is reported. The analysis is based on a data sample corresponding to an integrated luminosity of 1.0 fb-1 of pp collisions at √s = 7 TeV, collected with the LHCb detector. A yield of 30 ± 6 Bs0 → (K+K-)(K -π+) decays is found in the mass windows 1012:5 < M(K+K) < 1026:5MeV/c2 and 746 < M(K -π+) < 1046MeV/c2. The signal yield is found to be dominated by Bs0 → φK̄* 0 decays, and the corresponding branching fraction is measured to be B(Bs0 → φK̄*0) = (1:10 ± 0:24 (stat) ± 0:14 (syst) ± 0:08 (fd/f s)) × 10-6, where the uncertainties are statistical, systematic and from the ratio of fragmentation fractions fd/f s which accounts for the different production rate of B0 and Bs0 mesons. The significance of Bs0 → φK̄*0 signal is 6.1 standard deviations. The fraction of longitudinal polarization in Bs0 → φK̄*0 decays is found to be f 0 = 0:51 ± 0:15 (stat) ± 0:07 (syst). Copyright CERN.
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Limits on neutral Higgs boson production in the forward region in pp collisions at √s = 7 TeV

Journal of High Energy Physics 2013:5 (2013)

Authors:

R Aaij, CA Beteta, B Adeva, M Adinolfi, C Adrover, A Affolder, Z Ajaltouni, J Albrecht, F Alessio, M Alexander, S Ali, G Alkhazov, PA Cartelle, AA Alves, S Amato, S Amerio, Y Amhis, L Anderlini, J Anderson, R Andreassen, RB Appleby, OA Gutierrez, F Archilli, A Artamonov, M Artuso, E Aslanides, G Auriemma, S Bachmann, JJ Back, C Baesso, V Balagura, W Baldini, RJ Barlow, C Barschel, S Barsuk, W Barter, T Bauer, A Bay, J Beddow, F Bedeschi, I Bediaga, S Belogurov, K Belous, I Belyaev, E Ben-Haim, M Benayoun, G Bencivenni, S Benson, J Benton, A Berezhnoy, R Bernet, MO Bettler, M Van Beuzekom, A Bien, S Bifani, T Bird, A Bizzeti, PM Bjørnstad, T Blake, F Blanc, J Blouw, S Blusk, V Bocci, A Bondar, N Bondar, W Bonivento, S Borghi, A Borgia, TJV Bowcock, E Bowen, C Bozzi, T Brambach, J Van Den Brand, J Bressieux, D Brett, M Britsch, T Britton, NH Brook, H Brown, I Burducea, A Bursche, G Busetto, J Buytaert, S Cadeddu, O Callot, M Calvi, MC Gomez, A Camboni, P Campana, DC Perez, A Carbone, G Carboni, R Cardinale, A Cardini, H Carranza-Mejia, L Carson, KC Akiba, G Casse, M Cattaneo, C Cauet

Abstract:

Limits on the cross-section times branching fraction for neutral Higgs bosons, produced in pp collisions at √s = 7 TeV, and decaying to two tau leptons with pseudorapidities between 2.0 and 4.5, are presented. The result is based on a dataset, corresponding to an integrated luminosity of 1.0 fb -1, collected with the LHCb detector. Candidates are identified by reconstructing final states with two muons, a muon and an electron, a muon and a hadron, or an electron and a hadron. A model independent upper limit at the 95% confidence level is set on a neutral Higgs boson cross-section times branching fraction. It varies from 8.6 pb for a Higgs boson mass of 90 GeV to 0.7 pb for a Higgs boson mass of 250 GeV, and is compared to the Standard Model expectation. An upper limit on tan β in the Minimal Supersymmetric Model is set in the mh0max scenario. It ranges from 34 for a CP -odd Higgs boson mass of 90 GeV to 70 for a pseudo-scalar Higgs boson mass of 140 GeV. [Figure not available: see fulltext.] © 2013 Cern for the benefit of the LHCb collaboration.
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Low mass integrated cooling

Proceedings of Science 15-20-September-2013 (2013)

Authors:

A Mapelli, OA De Aguiar Francisco, J Buytaert, A Catinaccio, J Degrange, R Dumps, A Francescon, C Gargiulo, K Howell, M John, M Morel, J Noel, A Nomerotski, G Nuessle, P Petagna, G Romagnoli, P Renaud, M Van Stenis, B Verlaat

Abstract:

Low mass on-detector cooling systems are being developed and studied by the Detector Technology group (PH-DT) in the CERN Physics Department in close collaboration with LHC and non-LHC experiments. Two approaches are currently being investigated. The first approach, for barrel configurations, consists in integrating the cooling apparatus in light mechanical structures supporting the detectors. In this case, the thermal management can be achieved either with light cooling pipes and thin plates or with a network of microchannels embedded in thin strips of silicon or polyimide. Both configurations are being investigated in the context of the 2018 upgrade program of the ALICE Inner Tracking System (ITS). Moreover, it is also possible to use a silicon microchannel cooling device itself as structural support for the detectors and electronics. Such a configuration has been adopted by the NA62 collaboration for their GigaTracKer (GTK) as well as by the LHCb collaboration for the 2018 major upgrade of the Vertex Locator (VeLo).