A new algorithm for the determination of the initial flavour of B-s(0) mesons is presented. The algorithm is based on two neural networks and exploits the b hadron production mechanism at a hadron collider. The first network is trained to select charged kaons produced in association with the B-s(0) meson. The second network combines the kaon charges to assign the B-s(0) flavour and estimates the probability of a wrong assignment. The algorithm is calibrated using data corresponding to an integrated luminosity of 3 fb(-1) collected by the LHCb experiment in proton-proton collisions at 7 and 8 TeV centre-of-mass energies. The calibration is performed in two ways: by resolving the B-s(0)-B-s(0) flavour oscillations in B-s(0) -> D-s(-)pi(+) decays, and by analysing flavour-specific B-s2*(5840)(0) -> B+K- decays. The tagging power measured in B-s(0) -> D-s(-)pi(+) decays is found to be (1.80 +/- 0.19 ( stat) +/- 0.18 (syst))%, which is an improvement of about 50% compared to a similar algorithm previously used in the LHCb experiment.
A new algorithm for identifying the flavour of B-s(0) mesons at LHCb
2016-05-01
Aaij , R , Beteta , C A , Adeva , B , Adinolfi , M , Affolder , A , Ajaltouni , Z , Akar , S , Albrecht , J , Alessio , F , Alexander , M , Ali , S , Alkhazov , G , Cartelle , P A , Alves , A A , Amato , S , Amerio , S , Amhis , Y , An , L , Anderlini , L , Andreassi , G , Andreotti , M , Andrews , J E , Appleby , R B , Gutierrez , O A , Archilli , F , d'Argent , P , Artamonov , A , Artuso , M , Aslanides , E , Auriemma , G , Baalouch , M , Bachmann , S , Back , J J , Badalov , A , Baesso , C , Baldini , W , Barlow , R J , Barschel , C , Barsuk , S , Barter , W , Batozskaya , V , Battista , V , Beaucourt , L , Beddow , J , Bedeschi , F , Bediaga , I , Bel , L J , Onderwater , C J G , Pellegrino , A , Tolk , S & LHCb Collaboration 2016 , ' A new algorithm for identifying the flavour of B-s(0) mesons at LHCb ' , Journal of Instrumentation , vol. 11 , 05010 . https://doi.org/10.1088/1748-0221/11/05/P05010 ; ISSN:1748-0221
Article (Journal)
Electronic Resource
English
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