Measurement of b-hadron fractions in 13 TeV pp collisions
LHCb Collaboration, R. Aaij, C. Abellán Beteta, B. Adeva, M. Adinolfi, C.A. Aidala, Z. Ajaltouni, S. Akar, P. Albicocco, J. Albrecht, F. Alessio, M. Alexander, A. Alfonso Albero, G. Alkhazov, P. Alvarez Cartelle, A.A. Alves Jr, S. Amato, S. Amerio, Y. Amhis, L. An, L. Anderlini, G. Andreassi, M. Andreotti, J.E. Andrews, F. Archilli, J. Arnau Romeu, A. Artamonov, M. Artuso, K. Arzymatov, E. Aslanides, M. Atzeni, B. Audurier, S. Bachmann, J.J. Back, S. Baker, V. Balagura, W. Baldini, A. Baranov, R.J. Barlow, G.C. Barrand, S. Barsuk, W. Barter, M. Bartolini, F. Baryshnikov, V. Batozskaya, B. Batsukh, A. Battig, V. Battista, A. Bay, J. Beddow, F. Bedeschi, I. Bediaga, A. Beiter, L.J. Bel, S. Belin, N. Beliy, V. Bellee, N. Belloli, K. Belous, I. Belyaev, G. Bencivenni, E. Ben-Haim, S. Benson, S. Beranek, A. Berezhnoy, R. Bernet, D. Berninghoff, E. Bertholet, A. Bertolin, C. Betancourt, F. Betti, M.O. Bettler, Ia. Bezshyiko, S. Bhasin, J. Bhom, M.S. Bieker, S. Bifani, P. Billoir, A. Birnkraut, A. Bizzeti, M. Bjørn, M.P. Blago, T. Blake, F. Blanc, S. Blusk, D. Bobulska, V. Bocci, O. Boente Garcia, T. Boettcher, A. Bondar, N. Bondar, S. Borghi, M. Borisyak, M. Borsato, M. Boubdir, T.J.V. Bowcock, C. Bozzi, S. Braun, M. Brodski, J. Brodzicka, et al. (748 additional authors not shown)
EEUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH (CERN)
CERN-EP-2019-016LHCb-PAPER-2018-050February 18, 2019
Measurement of b -hadron fractionsin 13 TeV pp collisions LHCb collaboration † Abstract
The production fractions of B s and Λ b hadrons, normalized to the sum of B − and B fractions, are measured in 13 TeV pp collisions using data collected by the LHCbexperiment, corresponding to an integrated luminosity of 1.67 fb − . These ratios,averaged over the b -hadron transverse momenta from 4 to 25 GeV and pseudorapidityfrom 2 to 5, are 0 . ± .
006 for B s , and 0 . ± .
018 for Λ b , where the uncertaintiesarise from both statistical and systematic sources. The Λ b ratio depends stronglyon transverse momentum, while the B s ratio shows a mild dependence. Neitherratio shows variations with pseudorapidity. The measurements are made usingsemileptonic decays to minimize theoretical uncertainties. In addition, the ratioof D + to D mesons produced in the sum of B and B − semileptonic decays isdetermined as 0 . ± . ± . To be published in Physical Review D Rapid Communications c (cid:13) † Authors are listed at the end of this paper. a r X i v : . [ h e p - e x ] A ug inowledge of the fragmentation fractions of B s ( f s ) and Λ b ( f Λ b ) hadrons is essentialfor determining absolute branching fractions ( B ) of decays of these hadrons at the LHC,allowing measurements, for example, of B ( B s → µ + µ − ) [1] and the future evaluation of | V cb | from Λ b → Λ + c µ − ν µ decays [2]. Once these fractions are determined, measurementsof absolute branching fractions of B − and B mesons performed at e + e − colliders operatingat the Υ (4 S ) resonance can be used to determine the B s and Λ b branching fractions [3].In this Letter we measure the ratios f s / ( f u + f d ) and f Λ b / ( f u + f d ), where the denomi-nator is the sum of B − and B contributions, in the LHCb acceptance of pseudorapidity2 < η < < p T <
25 GeV, in 13 TeV pp collisions. Theseratios can depend on p T and η ; therefore, we perform the analysis using two-dimensionalbinning.Much of the analysis method adopted in this study is an evolution of our previous b -hadron fraction measurements for 7 TeV pp collisions [4]. We use the inclusive semilep-tonic decays H b → H c Xµ − ν µ , where H b indicates a b hadron, H c a charm hadron, and X possible additional particles. Each of the different H c plus muon final states can originatefrom the decay of different b hadrons. Semileptonic decays of B mesons usually result ina mixture of D and D + mesons, while B − mesons decay predominantly into D mesonswith a smaller admixture of D + mesons. Both include a tiny component of D + s K mesonpairs. Similarly, B s mesons decay predominantly into D + s mesons, but can also decay into D K + and D + K meson pairs; this is expected if the B s meson decays into an excited D + s state that is heavy enough to decay into a DK pair. We measure this contributionusing D K + Xµ − ν µ events. Finally, Λ b baryons decay semileptonically mostly into Λ + c final states, but can also decay into D p and D + n pairs. We ignore the contributionsof b → u decays that comprise approximately 1% of semileptonic b -hadron decays, andcontribute almost equally to all b -hadron species. The detailed equations relating theseyields to the final results are given in Ref. [4] and in the Supplemental material.The theoretical basis for this measurement is the near equality of semileptonic widths,Γ SL , for all b -hadron species [5] whose differences are predicted to precisions of about 1%.The values we use for the individual H b semileptonic branching fractions ( B SL ) are listedin Table 1. The H c decay modes used and their branching fractions are given in Table 2.The ratio of D + to D meson production in the sum of semileptonic B and B − decays, f + /f , is used to check the analysis method. This result can be related to models of thehadronic final states in B − and B semileptonic decays [6].The data sample corresponds to 1.67 fb − of integrated luminosity obtained withthe LHCb detector in 13 TeV pp collisions during 2016. The LHCb detector [7, 8] is asingle-arm forward spectrometer covering the pseudorapidity range 2 < η <
5, designed forthe study of particles containing b or c quarks. The detector elements that are particularlyrelevant to this analysis are: a silicon-strip vertex detector surrounding the pp interactionregion that allows c and b hadrons to be identified from their characteristically long flightdistance from the primary vertex (PV); a tracking system that provides a measurementof the momentum, p , of charged particles, two ring-imaging Cherenkov detectors that areable to discriminate between different species of charged hadrons, and a muon detectionsystem.The online event selection is performed by a trigger [9] which consists of a hardware Mention of a particular decay mode implies the use of the charge-conjugate one as well. We use natural units where c = (cid:126) = 1. able 1: Branching fractions of semileptonic b -hadron decays from direct measurements for B and B − mesons, ( (cid:104) B (cid:105) ≡ (cid:10) B + B − (cid:11) ), and derived for B s and Λ b hadrons based on the equalityof semileptonic widths and the lifetime ratios [3, 5]. Corrections to Γ SL for B s ( − . ± . Λ b (3 . ± . B and B − branching fraction measurementshave been taken into account. See Ref. [17] for more information. Particle τ (ps) B SL (%) B SL (%)measured measured used B . ± .
004 10 . ± .
19 10 . ± . B − . ± .
004 11 . ± .
20 11 . ± . (cid:104) B (cid:105) . ± .
19 10 . ± . B s . ± .
015 10 . ± . Λ b . ± .
010 10 . ± . p T or a hadron, photon or electron with hightransverse energy in the calorimeters. For hadrons, the transverse energy threshold is3.5 GeV. The software trigger requires a two-, three- or four-track secondary vertex witha significant displacement from any primary pp interaction vertex. At least one chargedparticle must have p T > . b hadron.Simulation is required to model the effects of the detector acceptance and the imposedselection requirements. Here pp collisions are generated using Pythia [11] with a specificLHCb configuration [12]. Decays of unstable particles are described by
EvtGen [13],in which final-state radiation is generated using
Photos [14]. The interaction of thegenerated particles with the detector, and its response, are implemented using the
Geant4 toolkit [15] as described in Ref. [16].Selection criteria are applied to muons and H c decay particles. The transverse mo-mentum of each hadron must be greater than 0.3 GeV, and that of the muon larger than1.3 GeV. Each track cannot point to any PV, implemented by requiring χ > χ is defined as the difference in the vertex-fit χ of a given PVreconstructed with and without the track under consideration being included. All final Table 2: Charm-hadron branching fractions for the decay modes used in this analysis. Note, the Λ + c branching fraction has been significantly improved since the previous analysis. Decay B (%) Source D → K − π + . ± .
05 PDG average [3] D + → K − π + π + . ± .
17 CLEO-c [18] D + s → K − K + π + . ± .
18 PDG average [3] Λ + c → pK − π + . ± .
33 From Refs. [19, 20]2 [MeV] ) + p - m(K C a nd i d a t e s / ( M e V ) LHCb (a) [MeV] ) + p + p - m(K C a nd i d a t e s / ( M e V ) LHCb (b) [MeV] ) + p - K + m(K C a nd i d a t e s / ( M e V ) LHCb (c) [MeV] ) + p - m(pK C a nd i d a t e s / ( M e V ) LHCb (d)
Figure 1: Fit to the mass spectra of the H c candidates of the selected H b decays: (a) D , (b) D + , (c) D + s mesons, and (d) the Λ + c baryon. The data are shown as black points with error bars.The signal component is shown as the dashed (green) line and the combinatorial backgroundcomponent is shown as the dashed (red) line. The solid (blue) line shows all components addedtogether. state particles are required to be positively identified using information from the RICHdetectors (PID). Particles from H c decay candidates must have a good fit to a commonvertex with χ /ndof <
9, where ndof is the number of degrees of freedom. They must alsobe well separated from the nearest PV, with the flight distance divided by its uncertaintygreater than 5.Candidate b hadrons are formed by combining H c and muon candidates originatingfrom a common vertex with χ /ndof < H c µ − invariant mass, m H c µ − , in therange 3.0–5.0 GeV for D and D + , 3.1–5.1 GeV for D + s and 3.3–5.3 GeV for Λ + c candidates.In addition, we define m corr ≡ (cid:113) m H c µ + p ⊥ + p ⊥ , where p ⊥ is the magnitude of thecombination’s momentum component transverse to the b -hadron flight direction; werequire that m corr > . . B s or Λ b candidates, respectively. For the D + s → K + K − π + decay mode, vetoes are employed to remove backgrounds from real D + or Λ + c decays where the particle assignments are incorrect.Background from prompt H c production at the PV needs to be considered. We usethe natural logarithm of the H c impact parameter, IP, with respect to the PV in units ofmm. Requiring ln(IP/mm) > − H c candidate mass spectra to find the b -hadron decay yields.The H c candidates mass distributions integrated over p T ( H b ) and η are shown inFig. 1. They consist of a prominent peak resulting from signal, and a small contributiondue to combinatorial background from random combinations of particles that pass theselection. They are fit with a signal component comprised of two Gaussian functions,3nd a combinatorial background component modeled as a linear function. The totalsignal yields for D Xµ − ν µ , D + Xµ − ν µ , D + s Xµ − ν µ and Λ + c µ − Xν µ are 13 775 000, 4 282 700,845 300, and 1 753 600, respectively.Background contributions to the b -hadron candidates include hadrons faking muons,false combinations of charm hadrons and muons from the two b hadrons in the event,as well as real muons and charm hadrons from B → DDX decays, where one of the D mesons decays into a muon. All the backgrounds are evaluated in two-dimensional η and p T intervals. The first two backgrounds are evaluated using events where the H c is combined with a muon of the wrong-sign ( e.g. D µ + ), forbidden in a semileptonic b -hadron decay. The wrong-sign backgrounds are <
1% for each H c species. The backgroundfrom B → DDX decays is determined by simulating a mixture of these decays usingtheir measured branching fractions [3]. The only decay mode significantly affected is B s → D + s Xµ − ν µ with contributions varying from 0.1% for D D − s X to 1.8% for D + s D − s X due to the large D + s → µ + ν decay rate. The total B → DDX background is (5 . ± . B s semileptonic decays is D + s Xµ − ν µ , where X containspossible additional hadrons. However, the B s meson also can decay into D K + or D + K instead of D + s , so we must add this component to the B s rate and subtract it from the f u + f d fraction. Similarly, in Λ b semileptonic decays we find a D pX component. Theselection criteria for these final states are similar to those for the D Xµ − ν µ and Λ + c Xµ − ν µ final states described above with the addition of a kaon or proton with p T >
300 MeVthat has been positively identified. A veto is also applied to reject D ∗ + → π + D decayswhere the pion mimics a kaon or a proton.These samples contain background, resonant and nonresonant decays. Separationof these components is achieved by using both right-sign ( H c with µ − ) and wrong-sign( H c with µ + ) candidates. In addition, the logarithm of the difference between thevertex χ formed by the added hadron track and the Dµ system and the vertex χ ofthe Dµ system, ln(∆ χ ), provides separation between combinatorial background andnonresonant semileptonic decays. True resonant and nonresonant B s → D K + µ − ν µ or Λ b → D pµ − ν µ decays peak in the ln(∆ χ ) distribution at a value of unity whilethe background is smooth and rises at higher values as the added track is generallynot associated with the D µ − vertex. To distinguish signal from background we define m ( D h ) C ≡ m ( D h ) − m ( D ) + m ( D ) PDG , and perform two-dimensional fits to the m ( D h ) C and ln(∆ χ ) distributions, where h = K + ( p ) for right-sign B s ( Λ b ) decays.The wrong-sign shapes are used to model the backgrounds. The resonant structuresare modeled with relativistic Breit–Wigner functions convoluted with Gaussians to takeinto account the experimental resolution, except for the narrow D s (2536) + which ismodeled with the sum of two Gaussians with a fixed mean. The nonresonant shape forthe ln(∆ χ ) distribution is taken as the same as the resonant one. Figure 2 shows thedata and result of the fits for B s and Λ b candidates.For the B s case, we find 22 610 ± D s (2536) + , 14 290 ± D ∗ s (2573) + , and38 140 ±
460 nonresonant decays, confirming the existence of both the D + s [21, 22] and D ∗ + s [22] particles in semileptonic B s decays with substantially more data, and showingthe existence of the nonresonant component. To account for the unmeasured D + K channel we take different mixtures of D ∗ and D final states for the different resonantand nonresonant components. The D + s decays dominantly into D ∗ , while the D ∗ + s decaysdominantly into D mesons [3]. For the nonresonant part we assume equal D ∗ and D yields. 4 [MeV] C ) – K D ( m C a nd i d a t e s / ( M e V ) LHCb (a) ) V2 cD ( ln -4 -2 0 2 4 C a nd i d a t e s / ( . ) LHCb (b) [MeV] C ) ) - ( p D(m C a nd i d a t e s / ( M e V ) LHCb (c) ) V2 cD ( ln -4 -2 0 2 4 C a nd i d a t e s / ( . ) LHCb (d)
Figure 2: Projections of the two-dimensional fits to the (a) m ( D K ± ) C and (c) m ( D ( ) p ) C mass distributions and (b, d) ln(∆ χ ) for (top) D K ± Xµ − ν µ candidates, and (bottom) for D ( ) p Xν µ candidates. The curves show projections of the 2D fit. The dashed (red) curvesshow the D + s and D ∗ + s resonant components in (a) and (b), and Λ + c (2860), Λ + c (2880) and Λ + c (2940) resonant components in (c) and (d). The long-dashed-dotted (green) curves show thenonresonant component, the dotted (black) curves are the background components, whose shapesare determined from wrong-sign combinations, and the solid (blue) curve shows all componentsadded together. In the Λ b case, we find 6120 ± Λ + c (2860), 2200 ± Λ + c (2880), 1200 ± Λ + c (2940),and 29 770 ±
690 nonresonant events. The decay rate into D p is assumed to be equal tothat into D + n using isospin conservation. All decays with an extra hadron have lowerdetection efficiencies than the sample without.Efficiencies for all the samples are determined using data in two-dimensional p T and η bins. Trigger efficiencies are determined using a sample of B − → J/ψ K − , with J/ψ → µ + µ − decays where only one muon track is positively identified, in conjunction withviewing the effects of combinations of different triggers [23]. This sample is also used todetermine muon identification efficiencies. Decays of J/ψ mesons to muons reconstructedusing partial information from the tracking system, e.g. eliminating the vertex locatorinformation, are also used to determine tracking efficiencies using data and to correctthe simulation. Finally, the PID efficiencies are evaluated using kaons and pions from D ∗ + → π + D decays, with D → K − π + , and protons from Λ → pπ − and Λ + c → pK − π + decays [24]. In the measurement of b -hadron fraction ratios many of the efficiencies canceland we are left with only residual effects to which we assign systematic uncertainties.The b -hadron η and p T , p T ( H b ), must be known because the b fractions can dependon production kinematics. While η can be evaluated directly using the measured primaryand secondary b vertices, the value of p T ( H b ) must be determined to account for themissing neutrino plus extra particles. The correction factor k is given by the ratio of the5verage reconstructed to true p T ( H b ) as a function of m ( H c µ − ) and is determined usingsimulation. It varies from 0.75 for m ( H c µ − ) equals 3 GeV to unity at m ( H c µ − ) = m ( H b ).The distribution of f s / ( f u + f d ) as a function of p T ( H b ) is shown in Fig. 3. We performa linear χ fit incorporating a full covariance matrix which takes into account the bin-by-bin correlations introduced from the kaon kinematics, and PID and tracking systematicuncertainties. The factor A in Eq. 1 incorporates the global systematic uncertaintiesdescribed later, which are independent of p T ( H b ). The resulting function is f s f u + f d ( p T ) = A [ p + p × ( p T − (cid:104) p T (cid:105) )] , (1)where p T here refers to p T ( H b ), A = 1 ± . p = 0 . ± . p = ( − . ± . · − GeV − , and (cid:104) p T (cid:105) = 10 . p T ( H b ), no η dependence is observed (see the Supplementalmaterial).We determine an average value for f s / ( f u + f d ) by dividing the yields of B s semileptonicdecays by the sum of B and B − semileptonic yields, which are all efficiency-corrected,between the limits of p T ( H b ) of 4 and 25 GeV and η of 2 and 5, resulting in f s f u + f d = 0 . ± . , where the uncertainty contains both statistical and systematic components, with the latterbeing dominant, and discussed subsequently. The total relative uncertainty is 4.8%. ) [GeV] b H ( T p F r ac ti on s L a nd s B LHCb = 13 TeVs u f + d f s f u f + d f b L f Figure 3: The ratios f s / ( f u + f d ) and f Λ b / ( f u + f d ) in bins of p T ( H b ). The B s data are indicatedby solid circles, while the Λ b by triangles. The smaller (black) error bars show the combinedbin-by-bin statistical and systematic uncertainties, and the larger (blue) ones show the globalsystematics added in quadrature. The fits to the data are shown as the solid (green) bands,whose widths represents the ± σ uncertainty limits on the fit shapes, and the dashed (black)lines give the total uncertainty on the fit results including the global scale uncertainty. In thehighest two p T bins the points have been displaced from the center of the bin. Λ b fraction as a function of p T ( H b ) demonstrating a large p T dependence. The distribution in η is flat. We perform a similar fit as in the B s fractioncase, using f Λ b f u + f d ( p T ) = A [ p + exp ( p + p × p T )] , (2)where p T here refers to p T ( H b ), A = 1 ± . p = (7 . ± . · − , p = − . ± . p = − . ± .
002 GeV − . The correlation coefficients among the fit parametersare 0.40 ( ρ ), –0.95 ( ρ ), and –0.63 ( ρ ).The average value for f Λ b / ( f u + f d ) is determined using the same method as in the B s case. The result is f Λ b f u + f d = 0 . ± . , where the dominant uncertainty is systematic, and the statistical uncertainty is included.The overall uncertainty is 6.9%.As a systematic check of the analysis method, and a useful measurement to test theknowledge of known semileptonic branching fractions and extrapolations used to saturatethe unknown portion of the inclusive hadron spectrum, we measure the ratio of the D Xµ − ν µ to D + Xµ − ν µ corrected yields f + /f . We subtract the small contributions from B s and Λ b decays, and a very small contribution from B → D + s Kµ − X decays has beentaken into account [25], as in all the fractions measured above.Assuming f u equals f d , Ref. [6] estimates the fraction of D + µ with respect to D µ modes in the sum of B − and B decays as 0 . ± . ± . D mesons used to saturate the remainingportion of the inclusive rate.The f + /f ratio must be independent of η and p T . To derive an overall value for f + /f , the p T ( H b ) distribution is fit to a constant. Only the PID and tracking systematicuncertainties on the second pion in the D + decay need be considered. Performing a χ fit using the full covariance matrix we find f + /f = 0 . ± . ± . χ /ndof is 0.63, in agreement with a flatspectrum. The measurement is consistent with the prediction and places some constraintson the D ∗∗ content of semileptonic B decays [6].The dominant global systematic uncertainties are listed in Table 3. Simulation uncer-tainties are due to the modeling of excited charm states for the f s / ( f u + f d ) determinationand the weighting required for the f Λ b / ( f u + f d ) ratio, due to differences between thesimulated and measured p T spectra. Background uncertainties arise from DDX finalstates with uncertain branching fractions. Cross-feed uncertainties come from errors onefficiency estimates and the assumed D ∗ to D mixtures. Other smaller uncertaintiesdepend on p T ( H b ) and include tracking (0.2–1.8)%, particle identification (0.4–3.0)%,trigger (0.3–3.9)% and k -factor (0.2–1.8)%.In conclusion, we measure the ratios of B s and Λ b production to the sum of B − and B to be p T ( H b ) dependent (see Eqs. 1 and 2). The averages in theranges 4 < p T ( H b ) <
25 GeV, and 2 < η < f s / ( f u + f d ) = 0 . ± . f Λ b / ( f u + f d ) = 0 . ± . f s / ( f u + f d ) = 0 . ± . p T ( H b ) slope larger than, but consistent with these7 able 3: Global systematic uncertainties. The D and D + branching fraction uncertainties arescaled by the fraction of each decay, f and f + for f s / ( f u + f d ) and f Λ b / ( f u + f d ) uncertainties. Source Value (%) f s / ( f u + f d ) f Λ b / ( f u + f d ) f + /f Simulation 1.7 2.4 –Backgrounds 0.9 0.3 –Cross-feeds 1.2 0.4 0.2 B ( D → K − π + ) 1.0 1.0 1.3 B ( D + → K + π − π − ) 0.6 0.6 1.8 B ( D + s → K + K − π + ) 3.3 – – B ( Λ + c → pK + π − ) – 5.3 –Measured lifetime ratio 1.2 0.7 –Γ SL correction 0.5 1.5 –Total 4.3 6.1 2.213 TeV results [26]; no dependence on η was observed. For the Λ b baryon, the fractionratio is consistent with the 7 TeV measurements after taking into account the different p T ( H b ) ranges used [4, 27, 28]. We observe no rapidity dependence over a similar p T ( H b )range as in Ref. [28].These results are crucial for determining absolute branching fractions of B s and Λ b hadron decays in LHC experiments. We also determine the ratio of D to D + mesonsproduced in the sum of B and B − semileptonic decays as f + /f = 0 . ± . ± . Acknowledgements
We express our gratitude to our colleagues in the CERN accelerator departments for theexcellent performance of the LHC. We thank the technical and administrative staff at theLHCb institutes. We acknowledge support from CERN and from the national agencies:CAPES, CNPq, FAPERJ and FINEP (Brazil); MOST and NSFC (China); CNRS/IN2P3(France); BMBF, DFG and MPG (Germany); INFN (Italy); NWO (Netherlands); MNiSWand NCN (Poland); MEN/IFA (Romania); MSHE (Russia); MinECo (Spain); SNSFand SER (Switzerland); NASU (Ukraine); STFC (United Kingdom); NSF (USA). Weacknowledge the computing resources that are provided by CERN, IN2P3 (France), KITand DESY (Germany), INFN (Italy), SURF (Netherlands), PIC (Spain), GridPP (UnitedKingdom), RRCKI and Yandex LLC (Russia), CSCS (Switzerland), IFIN-HH (Romania),CBPF (Brazil), PL-GRID (Poland) and OSC (USA). We are indebted to the communitiesbehind the multiple open-source software packages on which we depend. Individualgroups or members have received support from AvH Foundation (Germany); EPLANET,Marie Sk(cid:32)lodowska-Curie Actions and ERC (European Union); ANR, Labex P2IO andOCEVU, and R´egion Auvergne-Rhˆone-Alpes (France); Key Research Program of FrontierSciences of CAS, CAS PIFI, and the Thousand Talents Program (China); RFBR, RSFand Yandex LLC (Russia); GVA, XuntaGal and GENCAT (Spain); the Royal Society andthe Leverhulme Trust (United Kingdom); Laboratory Directed Research and Developmentprogram of LANL (USA). 8
Supplemental material H c µ − X measured yields and cor-rected yields The corrected yields for B or B − mesons decaying into D µ − ν µ X or D + µ − ν µ X , n corr ,can be expressed in terms of the measured yields, n , as n corr ( B → D µ − ) = 1 B ( D → K − π + ) (cid:15) ( B → D ) × (3) (cid:20) n ( D µ − ) − n ( D K + µ − ) (cid:15) ( B s → D ) (cid:15) ( B s → D K + ) − n ( D pµ − ) (cid:15) ( Λ b → D ) (cid:15) ( Λ b → D p ) (cid:21) , where we use the shorthand n ( Dµ − ) ≡ n ( DXµ − ν µ ). An analogous abbreviation (cid:15) is used for the total trigger and detection efficiencies. For example, the ratio (cid:15) ( B s → D K + ) /(cid:15) ( B s → D ) gives the relative efficiency to reconstruct a charged kaon insemimuonic B s decays producing a D meson. The second term in this equation accountsfor the D µ − pairs originating from a B s decay, such as B s → D K + µ − , while the thirdterm accounts for the D µ − pairs originating from Λ b semileptonic decays. These compo-nents are determined from the study of the final states D K + µ − and D pµ − respectively.The branching fraction B ( D → K − π + ) appears because this decay mode is used in thisstudy. Similarly n corr ( B → D + µ − ) = 1 (cid:15) ( B → D + ) (cid:20) n ( D + µ − ) B ( D + → K − π + π + ) − n ( D K + µ − ) B ( D → K − π + ) (cid:15) ( B s → D + ) (cid:15) ( B s → D K + ) − n ( D pµ − ) B ( D → K − π + ) (cid:15) ( Λ b → D + ) (cid:15) ( Λ b → D p ) (cid:21) . (4)Both the D Xµ − ν µ and the D + Xµ − ν µ final states contain small components of cross-feedfrom B s decays to D K + Xµ − ν µ and to D + K Xµ − ν µ , and from Λ b decays to D pXµ − ν µ and to D + nXµ − ν µ . Here we use isospin symmetry and infer the contributions by D + µ − pairs originating from a B s decay, such as B s → D + K µ − ν µ from the D K + µ − finalstates, and the contributions from Λ b → D + nµ − ν µ from the D pµ − yields.The number of B s → D + s Xµ − ν µ decays in the final state is given by n corr ( B s → D + s µ − ) = n ( D + s µ − ) B ( D + s → K + K − π + ) (cid:15) ( B s → D + s µ − ) − N ( B + B − ) B ( B → D + s K ) (cid:15) ( B → D + s K µ − ) (cid:15) ( B s → D + s µ − ) . (5)In addition, the B s meson decays semileptonically into DKXµ − ν µ , and thus we need toadd to Eq. 5 the term n corr ( B s → DKµ − ) = κ n ( D K + µ − ) B ( D → K − π + ) (cid:15) ( B s → D K + µ − ) , (6)9here κ accounts for the unmeasured B s → D + KXµ − ν µ semileptonic decays. Thecorrection κ is evaluated using the known decay modes of the D s (2536) + and D ∗ s (2573) + states and assuming that the nonresonant component of the hadronic mass spectrumdecays in equal portions into D or D ∗ final states. The last term in Eq. 5 accounts for D + s KXµ − ν µ final states originating from B or B − semileptonic decays, and N ( B + B − )indicates the total number of B and B − produced. We derive this correction using thePDG value for the branching fraction B ( B − → D ( ∗ )+ s K − µ − ν ) = (6 . ± . × − , andassuming the same rate for B s decays using isospin invariance [3].The equation for the ratio f s / ( f u + f d ) is f s f u + f d = n corr ( B s → Dµ − ) n corr ( B → D µ − ) + n corr ( B → D + µ − ) τ B − + τ B τ B s (1 − ξ s ) − B ( B → D s Kµ − ) (cid:104)B SL (cid:105) (cid:15) ( B → D + s ) (cid:15) ( B s → D + s ) , (7)where B s → Dµ represents B s semileptonic decays to a charmed hadron, given by the sumof the contributions shown in Eqs. 5 and 6, and the symbols τ B i indicate the B i hadronlifetimes, that are all well measured [3]. We use the average B s lifetime, 1 . ± .
015 ps.This equation assumes equality of the semileptonic widths of all the b -hadron species.This is a reliable assumption, as corrections in HQET arise only to order 1/ m b and theSU(3) breaking correction is quite small, ( − . ± . ξ s accountsfor this small adjustment. The second term is the subtraction of the B − , → D + s KXµ − ν µ component that is reconstructed in the signal sample as described in Eq. 5. The B SL termin the denominator is the semileptonic branching fraction of the B s derived using theequality of the semileptonic widths and the measured lifetime of the B s , listed in Table 1.The Λ b corrected yield is derived in an analogous manner n corr ( Λ b → H c µ − ) = n ( Λ + c µ − ) B ( Λ + c → pK − π + ) (cid:15) ( Λ b → Λ + c ) + 2 n ( D pµ − ) B ( D → K − π + ) (cid:15) ( Λ b → D p ) , (8)where H c represents a generic charmed hadron. The second term includes the cross-feedchannel and the factor of two accounts for the isospin Λ b → D + nµ − decay. The Λ b fraction is written as f Λ b f u + f d = n corr ( Λ b → H c µ − ) n corr ( B → D µ − ) + n corr ( B → D + µ − ) τ B − + τ B τ Λ b (1 − ξ Λ b ) . (9)While we assume near equality of the semileptonic widths of different b hadrons, we applya small adjustment ξ Λ b = (3 . ± . b -flavored mesons but not b baryons [5]. The uncertainty is evaluated withconservative assumptions for all the parameters of the heavy quark expansion.10 .2 Table of b -fractions versus p T ( H b ) Table 4: Values of f s / ( f u + f d ) and f Λ b / ( f u + f d ) in each p T ( H b ) bin. The first uncertainty isstatistical and incorporates both the uncertainties due to the data sample size and the finiteamount of simulated events, while the second is the overall systematic uncertainty, includingglobal and bin-dependent systematic uncertainties. p T ( H b )[GeV] f s / ( f u + f d ) f Λ b / ( f u + f d )4–5 0 . ± . ± .
007 0 . ± . ± . . ± . ± .
007 0 . ± . ± . . ± . ± .
006 0 . ± . ± . . ± . ± .
006 0 . ± . ± . . ± . ± .
006 0 . ± . ± . . ± . ± .
006 0 . ± . ± . . ± . ± .
006 0 . ± . ± . . ± . ± .
006 0 . ± . ± . . ± . ± .
006 0 . ± . ± . . ± . ± .
007 0 . ± . ± . . ± . ± .
006 0 . ± . ± . . ± . ± .
006 0 . ± . ± . . ± . ± .
008 0 . ± . ± . . ± . ± .
007 0 . ± . ± . η Figure 4 shows measurements of the fraction ratios f s / ( f u + f d ) and f Λ b / ( f u + f d ) asfunctions of η , integrated over p T . No η dependence is visible with the current datasample. h u f + d f s f LHCb = 13 TeVs h u f + d f b L f LHCb = 13 TeVs
Figure 4: Measurement of the fraction ratios (a) f s / ( f u + f d ) and (b) f Λ b / ( f u + f d ) as functionsof η integrated over p T . .4 Correlation matrices for the fits to f s / ( f u + f d ) and f Λ b / ( f u + f d ) Table 5 shows the covariance matrix among the different p T ( H b ) bins for f s / ( f u + f d ), whileTable 6 shows the covariance matrix among the different p T ( H b ) bins for f Λ b / ( f u + f d ).12 a b l e : C o v a r i a n ce m a t r i x f o r f s / ( f u + f d ) i n p T ( H b ) [ G e V ] b i n s ;i t a cc o un t s f o r s t a t i s t i c a l a ndb i n - d e p e nd e n t s y s t e m a t i c un ce r t a i n t i e s , bu t n o t t h e g l o b a l s y s t e m a t i c un ce r t a i n t i e s . p T ( H b ) . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E -
07 5–63 . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E -
07 6–71 . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E -
07 7–81 . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E -
07 8–99 . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E -
07 9–101 . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E -
07 10–111 . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E -
07 11–129 . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E -
07 12–137 . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E -
07 13–146 . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E -
07 14–166 . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E -
07 16–186 . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E -
07 18–205 . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E -
07 20–255 . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - a b l e : C o v a r i a n ce m a t r i x f o r f Λ b / ( f u + f d ) i n p T ( H b ) [ G e V ] b i n s ;i t a cc o un t s f o r s t a t i s t i c a l a ndb i n - d e p e nd e n t s y s t e m a t i c un ce r t a i n t i e s , bu t n o tt h e g l o b a l s y s t e m a t i c un ce r t a i n t i e s . p T ( H b ) . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - . E - eferences [1] CMS collaboration, V. Khachatryan et al. , Observation of the rare B s → µ + µ − decay from the combined analysis of CMS and LHCb data , Nature (2015) 68, arXiv:1411.4413 .[2] LHCb collaboration, R. Aaij et al. , Measurement of the shape of the Λ b → Λ + c µ − ν µ differential decay rate , Phys. Rev. D96 (2017) 112005, arXiv:1709.01920 .[3] Particle Data Group, M. Tanabashi et al. , Review of Particle Physics , Phys. Rev.
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Cindolo , P.E.L. Clarke ,M. Clemencic , H.V. Cliff , J. Closier , V. Coco , J.A.B. Coelho , J. Cogan , E. Cogneras ,L. Cojocariu , P. Collins , T. Colombo , A. Comerma-Montells , A. Contu , G. Coombs ,S. Coquereau , G. Corti , M. Corvo ,g , C.M. Costa Sobral , B. Couturier , G.A. Cowan ,D.C. Craik , A. Crocombe , M. Cruz Torres , R. Currie , F. Da Cunha Marinho ,C.L. Da Silva , E. Dall’Occo , J. Dalseno ,v , C. D’Ambrosio , A. Danilina , P. d’Argent ,A. Davis , O. De Aguiar Francisco , K. De Bruyn , S. De Capua , M. De Cian ,J.M. De Miranda , L. De Paula , M. De Serio ,d , P. De Simone , J.A. de Vries , C.T. Dean ,W. Dean , D. Decamp , L. Del Buono , B. Delaney , H.-P. Dembinski , M. Demmer ,A. Dendek , D. Derkach , O. Deschamps , F. Desse , F. Dettori , B. Dey , A. Di Canto ,P. Di Nezza , S. Didenko , H. Dijkstra , F. Dordei , M. Dorigo ,y , A.C. dos Reis ,A. Dosil Su´arez , L. Douglas , A. Dovbnya , K. Dreimanis , L. Dufour , G. Dujany ,P. Durante , J.M. Durham , D. Dutta , R. Dzhelyadin , † , M. Dziewiecki , A. Dziurda ,A. Dzyuba , S. Easo , U. Egede , V. Egorychev , S. Eidelman ,x , S. Eisenhardt ,U. Eitschberger , R. Ekelhof , L. Eklund , S. Ely , A. Ene , S. Escher , S. Esen ,T. Evans , A. Falabella , C. F¨arber , N. Farley , S. Farry , D. Fazzini , ,i , M. F´eo ,P. Fernandez Declara , A. Fernandez Prieto , F. Ferrari ,e , L. Ferreira Lopes ,F. Ferreira Rodrigues , M. Ferro-Luzzi , S. Filippov , R.A. Fini , M. Fiorini ,g , M. Firlej ,C. Fitzpatrick , T. Fiutowski , F. Fleuret ,b , M. Fontana , F. Fontanelli ,h , R. Forty ,V. Franco Lima , M. Frank , C. Frei , J. Fu ,q , W. Funk , E. Gabriel ,A. Gallas Torreira , D. Galli ,e , S. Gallorini , S. Gambetta , Y. Gan , M. Gandelman ,P. Gandini , Y. Gao , L.M. Garcia Martin , J. Garc´ıa Pardi˜nas , B. Garcia Plana ,J. Garra Tico , L. Garrido , D. Gascon , C. Gaspar , G. Gazzoni , D. Gerick ,E. Gersabeck , M. Gersabeck , T. Gershon , D. Gerstel , Ph. Ghez , V. Gibson ,O.G. Girard , P. Gironella Gironell , L. Giubega , K. Gizdov , V.V. Gligorov , C. G¨obel , . Golubkov , A. Golutvin , , A. Gomes ,a , I.V. Gorelov , C. Gotti ,i , E. Govorkova ,J.P. Grabowski , R. Graciani Diaz , L.A. Granado Cardoso , E. Graug´es , E. Graverini ,G. Graziani , A. Grecu , R. Greim , P. Griffith , L. Grillo , L. Gruber ,B.R. Gruberg Cazon , O. Gr¨unberg , C. Gu , E. Gushchin , A. Guth , Yu. Guz , ,T. Gys , T. Hadavizadeh , C. Hadjivasiliou , G. Haefeli , C. Haen , S.C. Haines ,B. Hamilton , X. Han , T.H. Hancock , S. Hansmann-Menzemer , N. Harnew ,T. Harrison , C. Hasse , M. Hatch , J. He , M. Hecker , K. Heinicke , A. Heister ,K. Hennessy , L. Henry , M. Heß , J. Heuel , A. Hicheur , R. Hidalgo Charman ,D. Hill , M. Hilton , P.H. Hopchev , J. Hu , W. Hu , W. Huang , Z.C. Huard ,W. Hulsbergen , T. Humair , M. Hushchyn , D. Hutchcroft , D. Hynds , P. Ibis ,M. Idzik , P. Ilten , A. Inglessi , A. Inyakin , K. Ivshin , R. Jacobsson , S. Jakobsen ,J. Jalocha , E. Jans , B.K. Jashal , A. Jawahery , F. Jiang , M. John , D. Johnson ,C.R. Jones , C. Joram , B. Jost , N. Jurik , S. Kandybei , M. Karacson , J.M. Kariuki ,S. Karodia , N. Kazeev , M. Kecke , F. Keizer , M. Kelsey , M. Kenzie , T. Ketel ,E. Khairullin , B. Khanji , C. Khurewathanakul , K.E. Kim , T. Kirn , V.S. Kirsebom ,S. Klaver , K. Klimaszewski , T. Klimkovich , S. Koliiev , M. Kolpin , R. Kopecna ,P. Koppenburg , I. Kostiuk , , S. Kotriakhova , M. Kozeiha , L. Kravchuk , M. Kreps ,F. Kress , P. Krokovny ,x , W. Krupa , W. Krzemien , W. Kucewicz ,l , M. Kucharczyk ,V. Kudryavtsev ,x , A.K. Kuonen , T. Kvaratskheliya , , D. Lacarrere , G. Lafferty ,A. Lai , D. Lancierini , G. Lanfranchi , C. Langenbruch , T. Latham , C. Lazzeroni ,R. Le Gac , R. Lef`evre , A. Leflat , F. Lemaitre , O. Leroy , T. Lesiak , B. Leverington ,P.-R. Li ,ab , Y. Li , Z. Li , X. Liang , T. Likhomanenko , R. Lindner , F. Lionetto ,V. Lisovskyi , G. Liu , X. Liu , D. Loh , A. Loi , I. Longstaff , J.H. Lopes , G. Loustau ,G.H. Lovell , D. Lucchesi ,o , M. Lucio Martinez , Y. Luo , A. Lupato , E. Luppi ,g ,O. Lupton , A. Lusiani , X. Lyu , F. Machefert , F. Maciuc , V. Macko , P. Mackowiak ,S. Maddrell-Mander , O. Maev , , K. Maguire , D. Maisuzenko , M.W. Majewski ,S. Malde , B. Malecki , A. Malinin , T. Maltsev ,x , H. Malygina , G. Manca ,f ,G. Mancinelli , D. Marangotto ,q , J. Maratas ,w , J.F. Marchand , U. Marconi ,C. Marin Benito , M. Marinangeli , P. Marino , J. Marks , P.J. Marshall , G. Martellotti ,M. Martinelli , D. Martinez Santos , F. Martinez Vidal , A. Massafferri , M. Materok ,R. Matev , A. Mathad , Z. Mathe , C. Matteuzzi , K.R. Mattioli , A. Mauri ,E. Maurice ,b , B. Maurin , M. McCann , , A. McNab , R. McNulty , J.V. Mead ,B. Meadows , C. Meaux , N. Meinert , D. Melnychuk , M. Merk , A. Merli ,q ,E. Michielin , D.A. Milanes , E. Millard , M.-N. Minard , L. Minzoni ,g , D.S. Mitzel ,A. M¨odden , A. Mogini , R.D. Moise , T. Momb¨acher , I.A. Monroy , S. Monteil ,M. Morandin , G. Morello , M.J. Morello ,t , O. Morgunova , J. Moron , A.B. Morris ,R. Mountain , F. Muheim , M. Mukherjee , M. Mulder , D. M¨uller , J. M¨uller ,K. M¨uller , V. M¨uller , C.H. Murphy , D. Murray , P. Naik , T. Nakada ,R. Nandakumar , A. Nandi , T. Nanut , I. Nasteva , M. Needham , N. Neri ,q ,S. Neubert , N. Neufeld , R. Newcombe , T.D. Nguyen , C. Nguyen-Mau ,n , S. Nieswand ,R. Niet , N. Nikitin , A. Nogay , N.S. Nolte , A. Oblakowska-Mucha , V. Obraztsov ,S. Ogilvy , D.P. O’Hanlon , R. Oldeman ,f , C.J.G. Onderwater , A. Ossowska ,J.M. Otalora Goicochea , T. Ovsiannikova , P. Owen , A. Oyanguren , P.R. Pais ,T. Pajero ,t , A. Palano , M. Palutan , G. Panshin , A. Papanestis , M. Pappagallo ,L.L. Pappalardo ,g , W. Parker , C. Parkes , , G. Passaleva , , A. Pastore , M. Patel ,C. Patrignani ,e , A. Pearce , A. Pellegrino , G. Penso , M. Pepe Altarelli , S. Perazzini ,D. Pereima , P. Perret , L. Pescatore , K. Petridis , A. Petrolini ,h , A. Petrov ,S. Petrucci , M. Petruzzo ,q , B. Pietrzyk , G. Pietrzyk , M. Pikies , M. Pili , D. Pinci ,J. Pinzino , F. Pisani , A. Piucci , V. Placinta , S. Playfer , J. Plews , M. Plo Casasus ,F. Polci , M. Poli Lener , A. Poluektov , N. Polukhina ,c , I. Polyakov , E. Polycarpo , .J. Pomery , S. Ponce , A. Popov , D. Popov , , S. Poslavskii , E. Price ,J. Prisciandaro , C. Prouve , V. Pugatch , A. Puig Navarro , H. Pullen , G. Punzi ,p ,W. Qian , J. Qin , R. Quagliani , B. Quintana , N.V. Raab , B. Rachwal ,J.H. Rademacker , M. Rama , M. Ramos Pernas , M.S. Rangel , F. Ratnikov , ,G. Raven , M. Ravonel Salzgeber , M. Reboud , F. Redi , S. Reichert , F. Reiss ,C. Remon Alepuz , Z. Ren , V. Renaudin , S. Ricciardi , S. Richards , K. Rinnert ,P. Robbe , A. Robert , A.B. Rodrigues , E. Rodrigues , J.A. Rodriguez Lopez ,M. Roehrken , S. Roiser , A. Rollings , V. Romanovskiy , A. Romero Vidal , J.D. Roth ,M. Rotondo , M.S. Rudolph , T. Ruf , J. Ruiz Vidal , J.J. Saborido Silva , N. Sagidova ,B. Saitta ,f , V. Salustino Guimaraes , C. Sanchez Gras , C. Sanchez Mayordomo ,B. Sanmartin Sedes , R. Santacesaria , C. Santamarina Rios , M. Santimaria , ,E. Santovetti ,j , G. Sarpis , A. Sarti ,k , C. Satriano ,s , A. Satta , M. Saur , D. Savrina , ,S. Schael , M. Schellenberg , M. Schiller , H. Schindler , M. Schmelling , T. Schmelzer ,B. Schmidt , O. Schneider , A. Schopper , H.F. Schreiner , M. Schubiger , S. Schulte ,M.H. Schune , R. Schwemmer , B. Sciascia , A. Sciubba ,k , A. Semennikov ,E.S. Sepulveda , A. Sergi , N. Serra , J. Serrano , L. Sestini , A. Seuthe , P. Seyfert ,M. Shapkin , T. Shears , L. Shekhtman ,x , V. Shevchenko , E. Shmanin , B.G. Siddi ,R. Silva Coutinho , L. Silva de Oliveira , G. Simi ,o , S. Simone ,d , I. Skiba , N. Skidmore ,T. Skwarnicki , M.W. Slater , J.G. Smeaton , E. Smith , I.T. Smith , M. Smith ,M. Soares , l. Soares Lavra , M.D. Sokoloff , F.J.P. Soler , B. Souza De Paula , B. Spaan ,E. Spadaro Norella ,q , P. Spradlin , F. Stagni , M. Stahl , S. Stahl , P. Stefko ,S. Stefkova , O. Steinkamp , S. Stemmle , O. Stenyakin , M. Stepanova , H. Stevens ,A. Stocchi , S. Stone , B. Storaci , S. Stracka , M.E. Stramaglia , M. Straticiuc ,U. Straumann , S. Strokov , J. Sun , L. Sun , Y. Sun , K. Swientek , A. Szabelski ,T. Szumlak , M. Szymanski , Z. Tang , T. Tekampe , G. Tellarini , F. Teubert ,E. Thomas , M.J. Tilley , V. Tisserand , S. T’Jampens , M. Tobin , S. Tolk ,L. Tomassetti ,g , D. Tonelli , D.Y. Tou , R. Tourinho Jadallah Aoude , E. Tournefier ,M. Traill , M.T. Tran , A. Trisovic , A. Tsaregorodtsev , G. Tuci ,p , A. Tully ,N. Tuning , , A. Ukleja , A. Usachov , A. Ustyuzhanin , , U. Uwer , A. Vagner ,V. Vagnoni , A. Valassi , S. Valat , G. Valenti , M. van Beuzekom , E. van Herwijnen ,J. van Tilburg , M. van Veghel , R. Vazquez Gomez , P. Vazquez Regueiro ,C. V´azquez Sierra , S. Vecchi , J.J. Velthuis , M. Veltri ,r , A. Venkateswaran , M. Vernet ,M. Veronesi , M. Vesterinen , J.V. Viana Barbosa , D. Vieira , M. Vieites Diaz ,H. Viemann , X. Vilasis-Cardona ,m , A. Vitkovskiy , M. Vitti , V. Volkov , A. Vollhardt ,D. Vom Bruch , B. Voneki , A. Vorobyev , V. Vorobyev ,x , N. Voropaev , R. Waldi ,J. Walsh , J. Wang , M. Wang , Y. Wang , Z. Wang , D.R. Ward , H.M. Wark ,N.K. Watson , D. Websdale , A. Weiden , C. Weisser , M. Whitehead , G. Wilkinson ,M. Wilkinson , I. Williams , M. Williams , M.R.J. Williams , T. Williams , F.F. Wilson ,M. Winn , W. Wislicki , M. Witek , G. Wormser , S.A. Wotton , K. Wyllie , D. Xiao ,Y. Xie , A. Xu , M. Xu , Q. Xu , Z. Xu , Z. Xu , Z. Yang , Z. Yang , Y. Yao ,L.E. Yeomans , H. Yin , J. Yu ,aa , X. Yuan , O. Yushchenko , K.A. Zarebski ,M. Zavertyaev ,c , D. Zhang , L. Zhang , W.C. Zhang ,z , Y. Zhang , A. Zhelezov ,Y. Zheng , X. Zhu , V. Zhukov , , J.B. Zonneveld , S. Zucchelli ,e . Centro Brasileiro de Pesquisas F´ısicas (CBPF), Rio de Janeiro, Brazil Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil Center for High Energy Physics, Tsinghua University, Beijing, China University of Chinese Academy of Sciences, Beijing, China Institute Of High Energy Physics (ihep), Beijing, China Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IN2P3-LAPP, Annecy, France Universit´e Clermont Auvergne, CNRS/IN2P3, LPC, Clermont-Ferrand, France Aix Marseille Univ, CNRS/IN2P3, CPPM, Marseille, France LAL, Univ. Paris-Sud, CNRS/IN2P3, Universit´e Paris-Saclay, Orsay, France LPNHE, Sorbonne Universit´e, Paris Diderot Sorbonne Paris Cit´e, CNRS/IN2P3, Paris, France I. Physikalisches Institut, RWTH Aachen University, Aachen, Germany Fakult¨at Physik, Technische Universit¨at Dortmund, Dortmund, Germany Max-Planck-Institut f¨ur Kernphysik (MPIK), Heidelberg, Germany Physikalisches Institut, Ruprecht-Karls-Universit¨at Heidelberg, Heidelberg, Germany School of Physics, University College Dublin, Dublin, Ireland INFN Sezione di Bari, Bari, Italy INFN Sezione di Bologna, Bologna, Italy INFN Sezione di Ferrara, Ferrara, Italy INFN Sezione di Firenze, Firenze, Italy INFN Laboratori Nazionali di Frascati, Frascati, Italy INFN Sezione di Genova, Genova, Italy INFN Sezione di Milano-Bicocca, Milano, Italy INFN Sezione di Milano, Milano, Italy INFN Sezione di Cagliari, Monserrato, Italy INFN Sezione di Padova, Padova, Italy INFN Sezione di Pisa, Pisa, Italy INFN Sezione di Roma Tor Vergata, Roma, Italy INFN Sezione di Roma La Sapienza, Roma, Italy Nikhef National Institute for Subatomic Physics, Amsterdam, Netherlands Nikhef National Institute for Subatomic Physics and VU University Amsterdam, Amsterdam,Netherlands Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences, Krak´ow, Poland AGH - University of Science and Technology, Faculty of Physics and Applied Computer Science,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 RAS), Moscow, Russia Yandex School of Data Analysis, Moscow, Russia Budker Institute of Nuclear Physics (SB RAS), Novosibirsk, Russia Institute for High Energy Physics (IHEP), Protvino, Russia ICCUB, Universitat de Barcelona, Barcelona, Spain Instituto Galego de F´ısica de Altas Enerx´ıas (IGFAE), Universidade de Santiago de Compostela,Santiago de Compostela, Spain European Organization for Nuclear Research (CERN), Geneva, Switzerland Institute of Physics, Ecole Polytechnique F´ed´erale de Lausanne (EPFL), Lausanne, Switzerland Physik-Institut, Universit¨at Z¨urich, Z¨urich, Switzerland 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 Massachusetts Institute of Technology, Cambridge, MA, United States University of Cincinnati, Cincinnati, OH, United States University of Maryland, College Park, MD, United States Syracuse University, Syracuse, NY, United States Laboratory of Mathematical and Subatomic Physics , Constantine, Algeria, associated to
Pontif´ıcia Universidade Cat´olica do Rio de Janeiro (PUC-Rio), Rio de Janeiro, Brazil, associated to
South China Normal University, Guangzhou, China, associated to
School of Physics and Technology, Wuhan University, Wuhan, China, associated to
Institute of Particle Physics, Central China Normal University, Wuhan, Hubei, China, associated to
Departamento de Fisica , Universidad Nacional de Colombia, Bogota, Colombia, associated to
Institut f¨ur Physik, Universit¨at Rostock, Rostock, Germany, associated to
Van Swinderen Institute, University of Groningen, Groningen, Netherlands, associated to
National Research Centre Kurchatov Institute, Moscow, Russia, associated to
National University of Science and Technology “MISIS”, Moscow, Russia, associated to
National Research University Higher School of Economics, Moscow, Russia, associated to
National Research Tomsk Polytechnic University, Tomsk, Russia, associated to
Instituto de Fisica Corpuscular, Centro Mixto Universidad de Valencia - CSIC, Valencia, Spain,associated to
University of Michigan, Ann Arbor, United States, associated to