DSpace at VNU: Measurement of the fragmentation fraction ratio f(s) f(d) and its dependence on B meson kinematics

Published for SISSA by Springer Received: January 23, 2013 Accepted: March 18, 2013 Published: April 2, 2013 The LHCb collaboration E-mail: Barbara.Storaci@cern.ch Abstract: The relative production rate of Bs0 and B mesons is determined with the hadronic decays Bs0 → Ds− π + and B → D− K + The measurement uses data corre√ sponding to 1.0 fb−1 of pp collisions at a centre-of-mass energy of s = TeV recorded in the forward region with the LHCb experiment The ratio of production rates, fs /fd , is measured to be 0.238 ± 0.004 ± 0.015 ± 0.021, where the first uncertainty is statistical, the second systematic, and the third theoretical This is combined with a previous LHCb measurement to obtain fs /fd = 0.256 ± 0.020 The dependence of fs /fd on the transverse momentum and pseudorapidity of the B meson is determined using the decays Bs0 → Ds− π + and B → D− π + There is evidence for a decrease with increasing transverse momentum, whereas the ratio remains constant as a function of pseudorapidity In addition, the ratio of branching fractions of the decays B → D− K + and B → D− π + is measured to be 0.0822 ± 0.0011 (stat) ± 0.0025 (syst) Keywords: Hadron-Hadron Scattering, Branching fraction, B physics, Flavor physics ArXiv ePrint: 1301.5286 Open Access, Copyright CERN, for the benefit of the LHCb collaboration doi:10.1007/JHEP04(2013)001 JHEP04(2013)001 Measurement of the fragmentation fraction ratio fs/fd and its dependence on B meson kinematics Contents Detector and software Event selection Event yields Systematic uncertainties Results Conclusions 10 The LHCb collaboration 13 Introduction The ratio of fragmentation fractions fs /fd quantifies the relative production rate of Bs0 mesons with respect to B mesons Knowledge of this quantity is essential when determining any Bs0 branching fraction at the LHC The measurement of the branching fraction of the rare decay Bs0 → µ+ µ− [1] is the prime example where a precise measurement of fs /fd is crucial for reaching the highest sensitivity in the search for physics beyond the Standard Model The branching fractions of a large number of B and B + decays have been measured to high precision at the B factories [2], but no Bs0 branching fraction is yet known with sufficiently high precision to be used as a normalisation channel The relative production rates of b hadrons are determined by the fragmentation fractions fu , fd , fs , fc and fΛ , which describe the probability that a b quark will hadronize into a Bq meson (where q = u, d, s, c), or a b baryon, respectively1 The ratio of fragmentation fractions fs /fd has been previously measured at LHCb with hadronic [3] and semileptonic decays [4], and the resulting values were combined [4] In this paper, the ratio of fragmentation fractions fs /fd is determined using Bs0 → Ds− π + and B → D− K + decays collected in pp collisions at a centre-of-mass energy of √ s = TeV, with data corresponding to an integrated luminosity of 1.0 fb−1 recorded with the LHCb detector Since the framework of factorization is well applicable to these decays [5], their ratio of branching fractions is theoretically well understood [6] and their Charge conjugation is implied throughout this paper –1– JHEP04(2013)001 Introduction relative decay rates can be used to determine the ratio of fragmentation fractions for Bs0 and B mesons through fs B(B → D− K + ) = fd B(Bs0 → Ds− π + ) = ΦPS Vus Vud fK fπ NDs π Ds π NDK DK τB B(D− → K + π − π − ) τBs0 Na NF B(Ds− → K + K − π − ) NDs π , Ds π NDK DK (1.1) Detector and software The LHCb detector [12] is a single-arm forward spectrometer covering the pseudorapidity range < η < 5, designed for the study of particles containing b or c quarks The detector includes a high precision tracking system consisting of a silicon-strip vertex detector surrounding the pp interaction region, a large-area silicon-strip detector located upstream of a dipole magnet with a bending power of about Tm, and three stations of silicon-strip detectors and straw drift tubes placed downstream Data are taken with both magnet polarities The combined tracking system has momentum resolution ∆p/p that varies from –2– JHEP04(2013)001 where N corresponds to a signal yield, corresponds to a total efficiency, τBs0 /τB = 0.984 ± 0.011 [7] corresponds to the ratio of lifetimes and B(D− → K + π − π − ) = (9.14 ± − 0.20)% [8] and B(Ds− → K + K − π − ) = (5.50 ± 0.27)% [9] correspond to the D(s) meson branching fractions The factor Na = 1.00 ± 0.02 accounts for the ratio of non-factorizable → D − form factors [11], and corrections [10], NF = 1.092 ± 0.093 for the ratio of B(s) (s) ΦPS = 0.971 for the difference in phase space due to the mass differences of the initial and final state particles The numerical values used for the CKM matrix elements are |Vus | = 0.2252, |Vud | = 0.97425, and for the decay constants are fπ = 130.41 MeV, fK = 156.1 MeV, with negligible uncertainties, below 1% [2] The measurement is not statistically limited by the size of the B → D− K + sample , and therefore the theoretically less clean B → D− π + decays, where exchange diagrams contribute to the total amplitude, not contribute to the knowledge of fs /fd The ratio of fragmentation fractions can depend on the centre-of-mass energy, as well meson, as was studied previously at LHCb with partially as on the kinematics of the B(s) reconstructed B decays [4] The dependence of the ratio of fragmentation fractions on meson is determined using the transverse momentum pT and pseudorapidity η of the B(s) fully reconstructed B → D− π + and Bs0 → Ds− π + decays Since it is only the dependence that is of interest here, the more abundant B → D− π + decay is used rather than the B → D− K + decay The B → D− K + and B → D− π + decays are also used to determine their ratio of branching fractions, which can be used to quantify non-factorizable effects in such heavy-to-light decays [10] The paper is organised as follows: the detector is described in section 2, followed by the event selection and the relative selection efficiencies in section The fit to the mass distributions and the determination of the signal yields are discussed in section The systematic uncertainties are presented in section 5, and the final results are given in section 3 Event selection The three decay modes, B → D− π + , B → D− K + and Bs0 → Ds− π + , are topologically very similar and can therefore be selected using the same event selection criteria, thus candidates are reconstructed minimizing efficiency differences between the modes The B(s) − from a D(s) candidate and an additional pion or kaon (the “bachelor” particle), with the − D(s) meson decaying to K + π − π − (K + K − π − ) and D − masses, After the trigger selection, a loose preselection is made using the B(s) (s) lifetimes and vertex qualities A boosted decision tree (BDT) [21] is used to further separate signal from background The BDT is trained on half the Bs0 → Ds− π + data sample The impact parameter χ2 , the pointing angle of the most discriminating variables are the B(s) B(s) candidate to the primary vertex and the pT of the tracks A cut value for the BDT output variable was chosen to optimally reduce the number of combinatorial background events, retaining approximately 84% of the signal events − The D(s) candidates are identified by requiring the invariant mass under the K + π − π − (K + K − π − ) hypothesis to fall within the selection window 1844–1890 (1944–1990) MeV/c2 The relative efficiency of the selection procedure is evaluated for all decay modes using simulated events, generated with the appropriate Dalitz plot structures [22, 23] Since the analysis is only sensitive to relative efficiencies, the impact of any discrepancy between data and simulation is small Impact parameter (IP) is defined as the transverse distance of closest approach between the track and a primary interaction –3– JHEP04(2013)001 0.4% at GeV/c to 0.6% at 100 GeV/c, and impact parameter2 resolution of 20 µm for tracks with high transverse momentum Charged hadrons are identified using two ring-imaging Cherenkov detectors The trigger [13] consists of a hardware stage, based on information from the calorimeter and muon systems, followed by a software stage which applies a full event reconstruction The events used in this analysis are selected at the hardware stage by requiring a cluster in the calorimeters with transverse energy larger than 3.6 GeV The software stage requires a two-, three- or four-track secondary vertex with a high sum of the pT of the tracks and a significant displacement from the primary pp interaction vertices (PVs) At least one track should have pT greater than 1.7 GeV/c, track fit χ2 over the number of degrees of freedom less than two, and IP χ2 with respect to the associated primary interaction greater than sixteen The IP χ2 is defined as the difference between the χ2 from the vertex fit of the associated PV reconstructed with and without the considered track A multivariate algorithm is used for the identification of the secondary vertices consistent with the decay of a b hadron In the simulation, pp collisions are generated using Pythia 6.4 [14] with a specific LHCb configuration [15] Decays of hadronic particles are described by EvtGen [16], whilst final state radiation is generated using Photos [17] The interaction of the generated particles with the detector and its response are implemented using the Geant4 toolkit [18, 19] as described in ref [20] 4 Event yields The relative yields of the three decay modes are determined from unbinned extended maxi0 candidates as shown mum likelihood fits to the mass distributions of the reconstructed B(s) in figure In order to achieve the highest sensitivity, the sample is separated according to the two magnet polarities, allowing for possible differences in PID performance and in running conditions A simultaneous fit to the two magnet polarities is performed for each decay mode, with the peak position and width of each signal shared between the two The signal mass shape is described by a Gaussian distribution with power-law tails on either side to model the radiative tail and non-Gaussian detector effects It consists of a Crystal Ball function [24]  (m−µ)2 m−µ   for > −α  e− 2σ2 , σ n −n fleft (m, α, n, µ, σ) = N · n n m−µ m−µ   · e−|α| /2 · −|α|− , for ≤ −α  |α| |α| σ σ (4.1) and a second, similar but mirrored, function to describe the right tail, resulting in the signal mass shape f2CB (m) = fleft (m) + fright (m) The parameters of the tails are obtained from simulated events The mean µ and the width σ of the Gaussian distribution are equal in both Crystal Ball functions, and are allowed to vary in the fit The parameter N is a normalisation factor Three classes of background are considered in the fit: fully reconstructed decays where at least one track is misidentified, partially reconstructed decays with or without misidentified tracks and combinatorial background The shapes of the invariant mass distributions for the partially reconstructed decays are taken from large samples of simulated events The main sources are B → D− ρ+ and B → D∗− π + (K + ) for the B → D− π + (K + ) sample, and Bs0 → Ds− ρ+ and Bs0 → Ds∗− π + for the Bs0 → Ds− π + sample –4– JHEP04(2013)001 The final Bs0 → Ds− π + , B → D− π + and B → D− K + event samples are obtained after particle identification (PID) criteria, based on the difference in log-likelihood between the kaon and pion hypotheses (DLL) The PID performance as a function of pT and η of the track is estimated from data using a calibration sample of approximately 27 million D∗− → D0 (K + π − )π − decays, of Λb → Λ− c π decays is allowed to vary in the fit The cross-feeds from B → D− K + and Bs0 → Ds− π + events in the B → D− π + signal is small, and are constrained to their respective predicted yields In addition, a contribution from the rare B → Ds− π + decay is expected with a yield of 3.3% compared to the Bs0 → Ds− π + signal, and is accounted for accordingly The combinatorial background consists of events with random pions and kaons, forming a fake D− or Ds− candidate, as well as real D− or Ds− mesons, that combine with a random pion or kaon The combinatorial background is modelled with an exponential shape The results of the fits are presented in figure 1, and the corresponding signal yields are listed in table The total yields of the decays B → D− π + and B → D− K + are used to determine the ratio of their branching fractions, while the event yields of the decays Bs0 → Ds− π + and B → D− K + are used to measure the average ratio of fragmentation fractions The dependence of the relative b-hadron production fractions as a function of the meson is studied in the ranges 2.0 < transverse momentum and pseudorapidity of the B(s) η < 5.0 and 1.5 < pT < 40 GeV/c, using B → D− π + and Bs0 → Ds− π + decays The Source (%) 0.7 2.0 1.2 1.0 1.0 0.7 0.5 0.8 0.4 3.1 Bs0→Ds− π + B 0→D− K + 0.7 2.0 1.1 1.0 1.5 1.0 0.6 1.0 — 3.4 (%) Bs0→Ds− π + B 0→D− π + (%) 2.0 − 2.9 0.8 1.2 1.5 1.1 0.8 [correl.] [correl.] [correl.] 3.2 − 3.8 Table Systematic uncertainties for the measurement of the corrected ratio of event yields used for the measurements of fs /fd and the relative branching fraction of B → D− K + The systematic uncertainty in pT and η bins is shown as a range in the last column, and the total systematic uncertainty is the quadratic sum of the uncorrelated uncertainties The systematic uncertainties on the ratio of B → D− π + and Bs0 → Ds− π + yields that are correlated among the bins not affect the dependence on pT or η, and are not accounted for in the total systematic uncertainty event sample is subdivided in 20 bins in pT and 10 bins in η, with the bin sizes chosen to obtain approximately equal number of events per bin The fitting model for each bin is the same as that for the integrated samples, apart from the treatment of the exponent of the combinatorial background distribution, which is fixed to the value obtained from the fits to the integrated sample Systematic uncertainties The systematic uncertainties on the measurement of the relative event yields of the B → D− π + , B → D− K + and Bs0 → Ds− π + decay modes are related to trigger and offline selection efficiency corrections, particle identification calibration and the fit model The response to charged pions and kaons of the hadronic calorimeter used at the hardware trigger level has been investigated As the hardware trigger mostly triggers on the high-pT bachelor, a systematic uncertainty of 2% is assigned to the ratio of trigger efficiencies for the decays B → D− K + and B → D− π + , estimated from dedicated studies with D∗− → D0 (K + π − )π − decays This uncertainty is assumed to be uncorrelated between the individual bins in the binned analysis The relative selection efficiencies from simulation are studied by varying the BDT criterion, changing the signal yields by about ±25% The variation of the relative efficiency is 1.0% which is assigned as systematic uncertainty The uncertainty on the PID efficiencies is estimated by comparing, in simulated events, the results obtained using the D∗− calibration sample to the true simulated PID perfor- –7– JHEP04(2013)001 Detector acceptance and reconstruction Hardware trigger efficiency Offline selection BDT cut PID selection Comb background Signal shape (tails) Signal shape (core) Charmless background Total B 0→D− π + B 0→D− K + Results The relative signal yields of the decays B → D− π + , B → D− K + and Bs0 → Ds− π + are used to determine the branching fraction of the decay B → D− K + , and the ratio of fragmentation fractions fs /fd The efficiency corrected ratio of B → D− K + and B → D− π + signal yields results in the ratio of branching fractions B B → D− K + = 0.0822 ± 0.0011 (stat) ± 0.0025 (syst) B (B → D− π + ) –8– JHEP04(2013)001 mance on the signal decays The corresponding uncertainty ranges from 1.0% to 1.5% for the different measurements The exponent of the combinatorial background distribution is allowed to vary in the fits to the B → D− π + and Bs0 → Ds− π + mass distributions By studying D− π − and D− K − combinations, it is suggested that the value of the exponent is smaller for the B → D− K + decays than for the B → D− π + decays, and therefore in the fit to the B → D− K + candidates the exponent is fixed to half the value found in the fit to the B → D− π + sample The uncertainty on the signal yields due to the shape of the combinatorial background is estimated by reducing the exponent to half its value in the fits to the B → D− π + and Bs0 → Ds− π + mass distributions, and by taking a flat background for the fit to the B → D− K + mass distribution An uncertainty of 1.0% (0.7%) is assigned to the relative B → D− K + and Bs0 → Ds− π + (B → D− π + ) yields The tails of the signal distributions are fixed from simulation due to the presence of large amounts of partially reconstructed decays in the lower sidebands The uncertainty on the signal yield is estimated by varying the parameters that describe the tails by 10% The uncertainty from the shape of the central peak is taken from a fit allowing for two different widths for the Crystal Ball functions in eq 4.1, leading to a 1.0% (0.8%) uncertainty on the relative B → D− K + and Bs0 → Ds− π + (B → D− π + ) yields The contribution of charmless B decays without an intermediate D meson is ignored in the fit To evaluate the systematic uncertainty due to these decays, the B mass spectra for candidates in the sidebands of the D mass distribution are examined A contribution of 0.4% relative to the signal yield is found in the B → D− π + decay mode, and no contribution is seen in the other modes For the B → D− π + decay mode no correction is applied and the full size is taken as an uncertainty No systematic uncertainty is assigned for the other decay modes The various sources of the systematic uncertainty that contribute to the uncertainties on the ratios of signal yields are listed in table No uncertainty is associated to the + Λb → Λ− c π background, as the yield is allowed to vary in the fit Other cross checks, like + varying the B → Ds− π + yield in the Bs0 → Ds− π + fit or including Λb → Λ− c K in the − + B → D K fit, show a negligible effect on the signal yields All systematic variations are also performed in bins, and the corresponding relative changes in the ratio of yields have been quantified Variations showing correlated behaviour not affect the slope and are therefore not considered further 0.35 d (a) fs f LHCb / / fs f d 0.35 0.3 0.3 0.25 0.25 0.2 10000 20000 30000 0.2 40000 p (B) [MeV/ c] (b) LHCb η(B) Figure Ratio of fragmentation fractions fs /fd as functions of (a) pT and (b) η The errors on the data points are the statistical and uncorrelated systematic uncertainties added in quadrature The solid line is the result of a linear fit, and the dashed line corresponds to the fit for the no-dependence hypothesis The average value of pT or η is determined for each bin and used as the center of the bin The horizontal error bars indicate the bin size Note that the scale is zero suppressed This is combined with the world average branching fraction B B → D− π + = (26.8 ± 1.3) × 10−4 [2], to give B B → D− K + = (2.20 ± 0.03 ± 0.07 ± 0.11) × 10−4 , where the first uncertainty is statistical, the second is systematic and the last is due to the uncertainty on the B → D− π + branching fraction The ratio of fragmentation fractions is determined from the efficiency corrected event yields The ratio of efficiencies is 0.913 ± 0.027 This results in fs = (0.261 ± 0.004 ± 0.017) × fd Na NF = 0.238 ± 0.004 ± 0.015 ± 0.021 , where the first uncertainty is statistical, the second is systematic containing the sources listed in table as well as errors from external measurements, and the third is theoretical, due to the knowledge of Na and NF The last source is dominated by the uncertainty on the form factor ratio This measurement supersedes and is in agreement with the previous determination with hadronic decays [3] It also agrees with the previous measurement based on semileptonic decays [4] The two independent results are combined taking into account the various − sources of correlated systematic uncertainties, notably the D(s) branching fractions and B(s) lifetimes, to give fs = 0.256 ± 0.020, fd which supersedes the previous measurement from LHCb –9– (6.1) JHEP04(2013)001 T The value of fs /fd in bins of pT or η is determined using the Bs0 → Ds− π + and B → D− π + decay modes and is presented in figure A linear χ2 fit gives fs /fd (pT ) = (0.256 ± 0.020) + (−2.0 ± 0.6) × 10−3 / GeV/c × (pT − pT ) fs /fd (η) = (0.256 ± 0.020) + (0.005 ± 0.006) × (η − η ), Conclusions The relative production rate of Bs0 and B mesons is determined using the hadronic decays Bs0 → Ds− π + and B → D− K + resulting in fs /fd = 0.238 ± 0.004(stat) ± 0.015(syst) ± 0.021(theo) This value is consistent with a previous LHCb measurement based on semileptonic decays, with which it is averaged to obtain fs /fd = 0.256 ± 0.020 The ratio of fragmentation fractions fs /fd is determined as a function of the transverse momentum meson, and a variation consistent with a linear depenand pseudorapidity of the B(s) meson is observed, with a significance dence on the transverse momentum of the the B(s) of three standard deviations In addition, the ratio of branching fractions of the decays B → D− K + and B → D− π + is measured to be 0.0822 ± 0.0011 (stat) ± 0.0025 (syst) Acknowledgments We express our gratitude to our colleagues in the CERN accelerator departments for the excellent performance of the LHC We thank the technical and administrative staff at the LHCb institutes We acknowledge support from CERN and from the national agencies: CAPES, CNPq, FAPERJ and FINEP (Brazil); NSFC (China); CNRS/IN2P3 and Region Auvergne (France); BMBF, DFG, HGF and MPG (Germany); SFI (Ireland); INFN (Italy); FOM and NWO (The Netherlands); SCSR (Poland); ANCS/IFA (Romania); MinES, Rosatom, RFBR and NRC “Kurchatov Institute” (Russia); MinECo, XuntaGal and GENCAT (Spain); SNSF and SER (Switzerland); NAS Ukraine (Ukraine); STFC (United Kingdom); NSF (USA) We also acknowledge the support received from the ERC under FP7 The Tier1 computing centres are supported by IN2P3 (France), KIT and BMBF (Germany), INFN (Italy), NWO and SURF (The Netherlands), PIC (Spain), GridPP (United Kingdom) We are thankful for the computing resources put at our disposal by Yandex LLC (Russia), as well as to the communities behind the multiple open source software packages that we depend on Open Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited – 10 – JHEP04(2013)001 with pT = 10.4 GeV/c and η = 3.28 The data points are normalised with a scale factor to match the average value of 0.256 The uncertainty associated to this parameter is taken from eq 6.1, whilst the error from the fit is 0.003 for both pT and η The p-value for this linear fit is found to be 0.16 (0.87) for pT (η) The observed slope meson deviates from zero with for the dependence on the transverse momentum of the B(s) a significance of three standard deviations No indication of a dependence on η(B) is found References [1] LHCb collaboration, First evidence for the decay Bs → µ+ µ− , Phys Rev Lett 110 (2013) 021801 [arXiv:1211.2674] [INSPIRE] [2] Particle Data Group collaboration, J Beringer et al., Review of particle physics, Phys Rev D 86 (2012) 010001 [INSPIRE] [3] LHCb collaboration, Determination of fs /fd for TeV pp collisions and a measurement of the branching fraction of the decay Bd → D− K + ”, Phys Rev Lett 107 (2011) 211801 [arXiv:1106.4435] [INSPIRE] [5] M Beneke, G Buchalla, M Neubert and C.T Sachrajda, QCD factorization for exclusive, nonleptonic B meson 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collaboration, G Bonvicini et al., Dalitz plot analysis of the D+ → K − π + π + decay, Phys Rev D 78 (2008) 052001 [arXiv:0802.4214] [INSPIRE] The LHCb collaboration – 13 – JHEP04(2013)001 R Aaij38 , C Abellan Beteta33,n , A Adametz11 , B Adeva34 , M Adinolfi43 , C Adrover6 , A Affolder49 , Z Ajaltouni5 , J Albrecht35 , F Alessio35 , M Alexander48 , S Ali38 , G Alkhazov27 , P Alvarez Cartelle34 , A.A Alves Jr22,35 , S Amato2 , Y Amhis7 , L Anderlini17,f , J Anderson37 , R Andreassen57 , R.B Appleby51 , O Aquines Gutierrez10 , F Archilli18 , A Artamonov 32 , M Artuso53 , E Aslanides6 , G Auriemma22,m , S Bachmann11 , J.J Back45 , C Baesso54 , V Balagura28 , W Baldini16 , R.J Barlow51 , C Barschel35 , S Barsuk7 , W Barter44 , A Bates48 , Th Bauer38 , A Bay36 , J Beddow48 , I Bediaga1 , S Belogurov28 , K Belous32 , I Belyaev28 , E Ben-Haim8 , M Benayoun8 , G Bencivenni18 , S Benson47 , J Benton43 , A Berezhnoy29 , R Bernet37 , M.-O Bettler44 , M van Beuzekom38 , A Bien11 , S Bifani12 , T Bird51 , A Bizzeti17,h , P.M Bjørnstad51 , T Blake35 , F Blanc36 , C Blanks50 , J Blouw11 , S Blusk53 , A Bobrov31 , V Bocci22 , A Bondar31 , N Bondar27 , W Bonivento15 , S Borghi51 , A Borgia53 , T.J.V Bowcock49 , E Bowen37 , C Bozzi16 , T Brambach9 , J van den Brand39 , J Bressieux36 , D Brett51 , M Britsch10 , T Britton53 , N.H Brook43 , H Brown49 , A Bă uchler-Germann37 , I Burducea26 , A Bursche37 , J Buytaert35 , S Cadeddu15 , O Callot7 , M Calvi20,j , M Calvo Gomez33,n , A Camboni33 , P Campana18,35 , A Carbone14,c , G Carboni21,k , R Cardinale19,i , A Cardini15 , H Carranza-Mejia47 , L Carson50 , K Carvalho Akiba2 , G Casse49 , M Cattaneo35 , Ch Cauet9 , M Charles52 , Ph Charpentier35 , P Chen3,36 , N Chiapolini37 , M Chrzaszcz 23 , K Ciba35 , X Cid Vidal34 , G Ciezarek50 , P.E.L Clarke47 , M Clemencic35 , H.V Cliff44 , J Closier35 , C Coca26 , V Coco38 , J Cogan6 , E Cogneras5 , P Collins35 , A Comerma-Montells33 , A Contu15 , A Cook43 , M Coombes43 , G Corti35 , B Couturier35 , G.A Cowan36 , D Craik45 , S Cunliffe50 , R Currie47 , C D’Ambrosio35 , P David8 , P.N.Y David38 , I De Bonis4 , K De Bruyn38 , S De Capua51 , M De Cian37 , J.M De Miranda1 , L De Paula2 , W De Silva57 , P De Simone18 , D Decamp4 , M Deckenhoff9 , H Degaudenzi36,35 , L Del Buono8 , C Deplano15 , D Derkach14 , O Deschamps5 , F Dettori39 , A Di Canto11 , J Dickens44 , H Dijkstra35 , P Diniz Batista1 , M Dogaru26 , F Domingo Bonal33,n , S Donleavy49 , F Dordei11 , A Dosil Su´ arez34 , D Dossett45 , A Dovbnya40 , F Dupertuis36 , R Dzhelyadin32 , 23 A Dziurda , A Dzyuba27 , S Easo46,35 , U Egede50 , V Egorychev28 , S Eidelman31 , D van Eijk38 , S Eisenhardt47 , U Eitschberger9 , R Ekelhof9 , L Eklund48 , I El Rifai5 , Ch Elsasser37 , D Elsby42 , A Falabella14,e , C Făarber11 , G Fardell47 , C Farinelli38 , S Farry12 , V Fave36 , D Ferguson47 , V Fernandez Albor34 , F Ferreira Rodrigues1 , M Ferro-Luzzi35 , S Filippov30 , C Fitzpatrick35 , M Fontana10 , F Fontanelli19,i , R Forty35 , O Francisco2 , M Frank35 , C Frei35 , M Frosini17,f , S Furcas20 , E Furfaro21 , A Gallas Torreira34 , D Galli14,c , M Gandelman2 , P Gandini52 , Y Gao3 , J Garofoli53 , P Garosi51 , J Garra Tico44 , L Garrido33 , C Gaspar35 , R Gauld52 , E Gersabeck11 , M Gersabeck51 , T Gershon45,35 , Ph Ghez4 , V Gibson44 , V.V Gligorov35 , C Gă obel54 , D Golubkov28 , A Golutvin50,28,35 , A Gomes2 , 52 H Gordon , M Grabalosa G´ andara5 , R Graciani Diaz33 , L.A Granado Cardoso35 , 33 17 E Graug´es , G Graziani , A Grecu26 , E Greening52 , S Gregson44 , O Gră unberg55 , B Gui53 , E Gushchin30 , Yu Guz32 , T Gys35 , C Hadjivasiliou53 , G Haefeli36 , C Haen35 , S.C Haines44 , S Hall50 , T Hampson43 , S Hansmann-Menzemer11 , N Harnew52 , S.T Harnew43 , J Harrison51 , P.F Harrison45 , T Hartmann55 , J He7 , V Heijne38 , K Hennessy49 , P Henrard5 , J.A Hernando Morata34 , E van Herwijnen35 , E Hicks49 , D Hill52 , M Hoballah5 , C Hombach51 , P Hopchev4 , W Hulsbergen38 , P Hunt52 , T Huse49 , N Hussain52 , D Hutchcroft49 , D Hynds48 , V Iakovenko41 , P Ilten12 , J Imong43 , R Jacobsson35 , A Jaeger11 , E Jans38 , F Jansen38 , P Jaton36 , F Jing3 , M John52 , D Johnson52 , C.R Jones44 , B Jost35 , M Kaballo9 , S Kandybei40 , M Karacson35 , T.M Karbach35 , I.R Kenyon42 , U Kerzel35 , T Ketel39 , A Keune36 , B Khanji20 , O Kochebina7 , I Komarov36,29 , R.F Koopman39 , P Koppenburg38 , – 14 – JHEP04(2013)001 M Korolev29 , A Kozlinskiy38 , L Kravchuk30 , K Kreplin11 , M Kreps45 , G Krocker11 , P Krokovny31 , F Kruse9 , M Kucharczyk20,23,j , V Kudryavtsev31 , T Kvaratskheliya28,35 , V.N La Thi36 , D Lacarrere35 , G Lafferty51 , A Lai15 , D Lambert47 , R.W Lambert39 , E Lanciotti35 , G Lanfranchi18,35 , C Langenbruch35 , T Latham45 , C Lazzeroni42 , R Le Gac6 , J van Leerdam38 , J.-P Lees4 , R Lef`evre5 , A Leflat29,35 , J Lefran¸cois7 , O Leroy6 , Y Li3 , L Li Gioi5 , M Liles49 , R Lindner35 , C Linn11 , B Liu3 , G Liu35 , J von Loeben20 , J.H Lopes2 , E Lopez Asamar33 , N Lopez-March36 , H Lu3 , J Luisier36 , H Luo47 , A Mac Raighne48 , F Machefert7 , I.V Machikhiliyan4,28 , F Maciuc26 , O Maev27,35 , S Malde52 , G Manca15,d , G Mancinelli6 , N Mangiafave44 , U Marconi14 , R Măarki36 , J Marks11 , G Martellotti22 , A Martens8 , L Martin52 , A Mart´ın S´ anchez7 , M Martinelli38 , D Martinez Santos39 , D Martins Tostes , A Massafferri , R Matev35 , Z Mathe35 , C Matteuzzi20 , M Matveev27 , E Maurice6 , A Mazurov16,30,35,e , J McCarthy42 , R McNulty12 , B Meadows57,52 , F Meier9 , M Meissner11 , M Merk38 , D.A Milanes13 , M.-N Minard4 , J Molina Rodriguez54 , S Monteil5 , D Moran51 , P Morawski23 , R Mountain53 , I Mous38 , F Muheim47 , K Mă uller37 , R Muresan26 , 24 36 43 36 46 B Muryn , B Muster , P Naik , T Nakada , R Nandakumar , I Nasteva1 , M Needham47 , N Neufeld35 , A.D Nguyen36 , T.D Nguyen36 , C Nguyen-Mau36,o , M Nicol7 , V Niess5 , R Niet9 , N Nikitin29 , T Nikodem11 , S Nisar56 , A Nomerotski52 , A Novoselov32 , A Oblakowska-Mucha24 , V Obraztsov32 , S Oggero38 , S Ogilvy48 , O Okhrimenko41 , R Oldeman15,d,35 , M Orlandea26 , J.M Otalora Goicochea2 , P Owen50 , B.K Pal53 , A Palano13,b , M Palutan18 , J Panman35 , A Papanestis46 , M Pappagallo48 , C Parkes51 , C.J Parkinson50 , G Passaleva17 , G.D Patel49 , M Patel50 , G.N Patrick46 , C Patrignani19,i , C Pavel-Nicorescu26 , A Pazos Alvarez34 , A Pellegrino38 , G Penso22,l , M Pepe Altarelli35 , S Perazzini14,c , D.L Perego20,j , E Perez Trigo34 , A P´erez-Calero Yzquierdo33 , P Perret5 , M Perrin-Terrin6 , G Pessina20 , K Petridis50 , A Petrolini19,i , A Phan53 , E Picatoste Olloqui33 , B Pietrzyk4 , T Pilaˇr45 , D Pinci22 , S Playfer47 , M Plo Casasus34 , F Polci8 , G Polok23 , A Poluektov45,31 , E Polycarpo2 , D Popov10 , B Popovici26 , C Potterat33 , A Powell52 , J Prisciandaro36 , V Pugatch41 , A Puig Navarro36 , W Qian4 , J.H Rademacker43 , B Rakotomiaramanana36 , M.S Rangel2 , I Raniuk40 , N Rauschmayr35 , G Raven39 , S Redford52 , M.M Reid45 , A.C dos Reis1 , S Ricciardi46 , A Richards50 , K Rinnert49 , V Rives Molina33 , D.A Roa Romero5 , P Robbe7 , E Rodrigues51 , P Rodriguez Perez34 , G.J Rogers44 , S Roiser35 , V Romanovsky32 , A Romero Vidal34 , J Rouvinet36 , T Ruf35 , H Ruiz33 , G Sabatino22,k , J.J Saborido Silva34 , N Sagidova27 , P Sail48 , B Saitta15,d , C Salzmann37 , B Sanmartin Sedes34 , M Sannino19,i , R Santacesaria22 , C Santamarina Rios34 , E Santovetti21,k , M Sapunov6 , A Sarti18,l , C Satriano22,m , A Satta21 , M Savrie16,e , D Savrina28,29 , P Schaack50 , M Schiller39 , H Schindler35 , S Schleich9 , M Schlupp9 , M Schmelling10 , B Schmidt35 , O Schneider36 , A Schopper35 , M.-H Schune7 , R Schwemmer35 , B Sciascia18 , A Sciubba18,l , M Seco34 , A Semennikov28 , K Senderowska24 , I Sepp50 , N Serra37 , J Serrano6 , P Seyfert11 , M Shapkin32 , I Shapoval40,35 , P Shatalov28 , Y Shcheglov27 , T Shears49,35 , L Shekhtman31 , O Shevchenko40 , V Shevchenko28 , A Shires50 , R Silva Coutinho45 , T Skwarnicki53 , N.A Smith49 , E Smith52,46 , M Smith51 , K Sobczak5 , M.D Sokoloff57 , F.J.P Soler48 , F Soomro18,35 , D Souza43 , B Souza De Paula2 , B Spaan9 , A Sparkes47 , P Spradlin48 , F Stagni35 , S Stahl11 , O Steinkamp37 , S Stoica26 , S Stone53 , B Storaci37 , M Straticiuc26 , U Straumann37 , V.K Subbiah35 , S Swientek9 , V Syropoulos39 , M Szczekowski25 , P Szczypka36,35 , T Szumlak24 , S T’Jampens4 , M Teklishyn7 , E Teodorescu26 , F Teubert35 , C Thomas52 , E Thomas35 , J van Tilburg11 , V Tisserand4 , M Tobin37 , S Tolk39 , D Tonelli35 , S Topp-Joergensen52 , N Torr52 , E Tournefier4,50 , S Tourneur36 , M.T Tran36 , M Tresch37 , A Tsaregorodtsev6 , P Tsopelas38 , N Tuning38 , M Ubeda Garcia35 , A Ukleja25 , D Urner51 , U Uwer11 , V Vagnoni14 , G Valenti14 , R Vazquez Gomez33 , P Vazquez Regueiro34 , S Vecchi16 , J.J Velthuis43 , M Veltri17,g , G Veneziano36 , M Vesterinen35 , B Viaud7 , D Vieira2 , X Vilasis-Cardona33,n , A Vollhardt37 , D Volyanskyy10 , D Voong43 , A Vorobyev27 , V Vorobyev31 , C Voß55 , H Voss10 , R Waldi55 , R Wallace12 , S Wandernoth11 , J Wang53 , D.R Ward44 , N.K Watson42 , A.D Webber51 , D Websdale50 , M Whitehead45 , J Wicht35 , D Wiedner11 , L Wiggers38 , G Wilkinson52 , M.P Williams45,46 , M Williams50,p , F.F Wilson46 , J Wishahi9 , M Witek23 , W Witzeling35 , S.A Wotton44 , S Wright44 , S Wu3 , K Wyllie35 , Y Xie47,35 , F Xing52 , Z Xing53 , Z Yang3 , R Young47 , X Yuan3 , O Yushchenko32 , M Zangoli14 , M Zavertyaev10,a , F Zhang3 , L Zhang53 , W.C Zhang12 , Y Zhang3 , A Zhelezov11 , A Zhokhov28 , L Zhong3 , A Zvyagin35 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 Centro Brasileiro de Pesquisas F´ısicas (CBPF), Rio de Janeiro, Brazil Universidade Federal Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil Center for High Energy Physics, Tsinghua University, Beijing, China LAPP, Universit´e de Savoie, CNRS/IN2P3, Annecy-Le-Vieux, France Clermont Universit´e, Universit´e Blaise Pascal, CNRS/IN2P3, LPC, Clermont-Ferrand, France CPPM, Aix-Marseille Universit´e, CNRS/IN2P3, Marseille, France LAL, Universit´e Paris-Sud, CNRS/IN2P3, Orsay, France LPNHE, Universit´e Pierre et Marie Curie, Universit´e Paris Diderot, CNRS/IN2P3, Paris, France Fakultă at Physik, Technische Universită at Dortmund, Dortmund, Germany Max-Planck-Institut fă ur Kernphysik (MPIK), Heidelberg, Germany Physikalisches Institut, Ruprecht-Karls-Universită at Heidelberg, Heidelberg, Germany School of Physics, University College Dublin, Dublin, Ireland Sezione INFN di Bari, Bari, Italy Sezione INFN di Bologna, Bologna, Italy Sezione INFN di Cagliari, Cagliari, Italy Sezione INFN di Ferrara, Ferrara, Italy Sezione INFN di Firenze, Firenze, Italy Laboratori Nazionali dell’INFN di Frascati, Frascati, Italy Sezione INFN di Genova, Genova, Italy Sezione INFN di Milano Bicocca, Milano, Italy Sezione INFN di Roma Tor Vergata, Roma, Italy Sezione INFN di Roma La Sapienza, Roma, Italy Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences, Krak´ ow, Poland AGH University of Science and Technology, Krak´ ow, Poland National Center for Nuclear Research (NCBJ), Warsaw, Poland Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest-Magurele, Romania Petersburg Nuclear Physics Institute (PNPI), Gatchina, Russia Institute of Theoretical and Experimental Physics (ITEP), Moscow, Russia Institute of Nuclear Physics, Moscow State University (SINP MSU), Moscow, Russia Institute for Nuclear Research of the Russian Academy of Sciences (INR RAN), Moscow, Russia Budker Institute of Nuclear Physics (SB RAS) and Novosibirsk State University, Novosibirsk, Russia Institute for High Energy Physics (IHEP), Protvino, Russia Universitat de Barcelona, Barcelona, Spain Universidad de Santiago de Compostela, Santiago de Compostela, Spain European Organization for Nuclear Research (CERN), Geneva, Switzerland Ecole Polytechnique F´ed´erale de Lausanne (EPFL), Lausanne, Switzerland Physik-Institut, Universită at Ză urich, Ză urich, Switzerland Nikhef National Institute for Subatomic Physics, Amsterdam, The Netherlands Nikhef National Institute for Subatomic Physics and VU University Amsterdam, Amsterdam, The Netherlands – 15 – JHEP04(2013)001 40 41 42 43 44 45 46 47 48 49 50 52 53 54 55 56 57 a b c d e f g h i j k l m n o p P.N Lebedev Physical Institute, Russian Academy of Science (LPI RAS), Moscow, Russia Universit` a di Bari, Bari, Italy Universit` a di Bologna, Bologna, Italy Universit` a di Cagliari, Cagliari, Italy Universit` a di Ferrara, Ferrara, Italy Universit` a di Firenze, Firenze, Italy Universit` a di Urbino, Urbino, Italy Universit` a di Modena e Reggio Emilia, Modena, Italy Universit` a di Genova, Genova, Italy Universit` a di Milano Bicocca, Milano, Italy Universit` a di Roma Tor Vergata, Roma, Italy Universit` a di Roma La Sapienza, Roma, Italy Universit` a della Basilicata, Potenza, Italy LIFAELS, La Salle, Universitat Ramon Llull, Barcelona, Spain Hanoi University of Science, Hanoi, Viet Nam Massachusetts Institute of Technology, Cambridge, MA, United States – 16 – JHEP04(2013)001 51 NSC Kharkiv Institute of Physics and Technology (NSC KIPT), Kharkiv, Ukraine Institute for Nuclear Research of the National Academy of Sciences (KINR), Kyiv, Ukraine University of Birmingham, Birmingham, United Kingdom H.H Wills Physics Laboratory, University of Bristol, Bristol, United Kingdom Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom Department of Physics, University of Warwick, Coventry, United Kingdom STFC Rutherford Appleton Laboratory, Didcot, United Kingdom School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom School of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom Oliver Lodge Laboratory, University of Liverpool, Liverpool, United Kingdom Imperial College London, London, United Kingdom School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom Department of Physics, University of Oxford, Oxford, United Kingdom Syracuse University, Syracuse, NY, United States Pontif´ıcia Universidade Cat´ olica Rio de Janeiro (PUC-Rio), Rio de Janeiro, Brazil, associated to2 Institut fă ur Physik, Universită at Rostock, Rostock, Germany, associated to11 Institute of Information Technology, COMSATS, Lahore, Pakistan, associated to53 University of Cincinnati, Cincinnati, OH, United States, associated to53 ... studied previously at LHCb with partially as on the kinematics of the B( s) reconstructed B decays [4] The dependence of the ratio of fragmentation fractions on meson is determined using the transverse... determine the ratio of their branching fractions, while the event yields of the decays Bs0 → Ds− π + and B → D− K + are used to measure the average ratio of fragmentation fractions The dependence of the. .. + and Bs0 → Ds− π + are used to determine the branching fraction of the decay B → D− K + , and the ratio of fragmentation fractions fs /fd The efficiency corrected ratio of B → D− K + and B