D (s) Hadronic Decays From CLEO-c

Transcription

1 D () Hadronic Decay From CLEOc e e D D D D γ γ π π Peter Onyii Cornell Univerity CLEO Collaboration Charm 26, June 57, 26 Peter Onyii CLEOc Charm Hadronic Decay Charm 26 1 / 37

2 Outline Scope of hadronic decay analye (and thi talk) Analyi technique Reult: D /D /D abolute branching fraction D /D (m)π ± (n)π D S,L π D /D /D (φ, η, η )X Peter Onyii CLEOc Charm Hadronic Decay Charm 26 2 / 37

3 Scope and Phyic The hadronic decay of charmed meon are a very active field of tudy at CLEOc multiple talk are covering our reult: The Quantum Correlation Analyi (D. Aner) Dalitz analye (M. Dubrovin) High energy can [ GeV] (R. Poling) Thi talk will cover branching fraction reult. Phyic from branching fraction: Important a engineering number: Reference mode, e.g. D π and D π π, normalize many D and B decay Incluive rate help dientangle charm content Relative rate of decay meaure variou decay amplitude, probe final tate interaction Peter Onyii CLEOc Charm Hadronic Decay Charm 26 3 / 37

4 CLEOc CLEOc SC Quadrupole Pylon Solenoid Coil Barrel Calorimeter Ring Imaging Cherenkov Detector Drift Chamber Inner Drift Chamber / Beampipe Detector lightly modified from Υ phyic configuration: ilicon vertex detector replaced with (all tereo) drift chamber SC Quadrupole Rare Earth Quadrupole Endcap Calorimeter Iron Polepiece Solenoid magnetic field changed from 1.5T to 1.T to compenate for lowermomentum track Magnet Iron Barrel Muon Chamber DAQ, trigger, oftware, etc. from CLEOIII with only minor change Particle ID (from de/dx, Čerenkov) better due to lower p track Muon ytem now only ueful for high momentum (e.g. J/ψ µ µ ) Peter Onyii CLEOc Charm Hadronic Decay Charm 26 4 / 37

5 Dataet CLEOc ha accumulated: 281 pb 1 at ψ(377) DD at 6 nb The D /D abolute BF ue 56 pb 1 only, are being updated 2 pb 1 near 4.17 GeV D D at 1 nb, DD D D D D at 7 nb Only 75 pb 1 ued for reult here operating point CLEOc Scan Preliminary R E cm DD D D PDG Peter Onyii CLEOc Charm Hadronic Decay Charm 26 5 / 37

6 Analyi technique Thee analye ue ingle tag and double tag technique: Single tag event recontruct the ignal in event without regard for the ret of the event Double tag event recontruct the ignal oppoite a wellundertood (flavor tagging) decay Single tag: Full tatitic available Branching ratio only (ratio of ST yield) D BF affected by quantum correlation, epecially CP eigentate Double tag: Very clean Branching fraction from ratio of DT and ST yield Can infer L Flavor tag minimize quantum correlation Tag efficiency O(1)% Peter Onyii CLEOc Charm Hadronic Decay Charm 26 6 / 37

7 Tagging at different energie At ψ(377), only open charm channel are D D, D D Cut on E E cand E beam, fit in m BC E 2 beam p cand 2 At E cm = 4.17 GeV, multiple open channel. For D we ue D D We ue m BC a a proxy for momentum to chooe the D D twobody decay Fit are in invariant ma Charged, π ditinguihed uing de/dx (all momenta) and Čerenkov (for high momentum) Find π by combining pair of iolated hower in the CI calorimeter, requiring 3σ conitency with π ma (σ 6 MeV) Find S by combining pair of track that lie within a ma window Peter Onyii CLEOc Charm Hadronic Decay Charm 26 7 / 37

8 inematic Separation at Ecm = 4.17 GeV minv (GeV) minv v. mbc for π candidate MC 2.1 D refl D D D D D D DD D D p 2 2 Ebeam ~pcand Peter Onyii CLEOc Charm Hadronic Decay 2.5 mbc (GeV) Charm 26 8 / 37

9 D () Abolute Hadronic Branching Fraction: Overview D /D reference decay mode are D π and D π π The claic D reference decay ha been the excluive mode D φπ π Thi caue problem ince φ ignal i ambiguou given the preciion we will oon achieve. All reult here are incluive branching fraction only. Decay PDG 24 fit Rel uncert D π 3.8% 2.4% D π π 13.% 6.2% D π π π 7.46% 4.2% D π π 9.2% 6.5% D π π π 6.5% 17% D S π 1.41% 6.7% D S π π 4.85% 31% D S π π π 3.55% 14% D π.89% 9.% D S 1.8% 31% D π 4.3% 28% D π π D π π π 1.% 28% BaBar ha a 25 φπ meaurement, 34% higher than the PDG, with 13% error. Peter Onyii CLEOc Charm Hadronic Decay Charm 26 9 / 37

10 Abolute Hadronic Branching Fraction: General Method (Follow pioneering analyi at ψ(377) by Mark III... ) Exploit lowenergy production procee: At 3.77 GeV, open charm only produced a D D and D D At 4.17 GeV, D produced almot entirely a D D Single tag pin down ratio between mode, double tag etablih abolute BF cale Ue a χ 2 (D /D ) or maximum likelihood (D ) fit to the oberved yield to extract maximum information For D /D, double tag recontruct entire event. For D, we only recontruct the D D (the γ or π from the D D tranition i ignored) Peter Onyii CLEOc Charm Hadronic Decay Charm 26 1 / 37

11 D /D Yield Extraction Event / (.2 GeV/c 2 ) Event / (.12 GeV/c 2 ) DATA: Single tag D π D π π D π S D π π π π D π D π S π D π π π D π π π S M (GeV/c 2 ) D D M (GeV/c 2 ) D D D π DATA: Double tag projection Event / (.12 GeV/c 2 ) M (GeV/c 2 ) Fit ignal with a priori function of phyical parameter (detector momentum reolution, beam energy pread, ψ(377) linehape, ISR pectrum) Smooth background fit a combinatoric phae pace ( ARGUS function ) Peaking background etimated from known BF and ubtracted In double tag, fit 2D plane of M BC (1) v. M BC (2) Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

12 D /D Sytematic Uncertaintie (56 pb 1 analyi) Source Fractional uncertainty (%) Tracking/ S /π.7/3./2. per particle Particle ID.3 per π, 1.3 per Trigger efficiency <.2 E cut per D FSR modeling.5 per ingle tag ψ width.6 Reonant ubtructure Event environment. 1.3 Yield fit function.5 Mic. event election.3 Double DCSD interference.8 in neutral double tag D π uncert 2.3%, D π π uncert 2.8% For thee, larget contributor are kaon PID and E cut Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

13 D /D Reult Branching fraction... Mode Value B(D π ) (3.91±.8±.9)% B(D π π ) (14.9 ±.3 ±.5)% B(D π π π ) (8.3 ±.2 ±.3)% B(D π π ) (9.5±.2±.3)% B(D π π π ) (6. ±.2 ±.2)% B(D S π ) (1.55 ±.5 ±.6)% B(D S π π ) (7.2 ±.2 ±.4)% B(D S π π π ) (3.2 ±.1 ±.2)% B(D π ) (.97 ±.4 ±.4)% σ D D (nb) σ D D (nb) σ DD (nb) σ D D /σ D D 2.79 ± ± ± ± and cro ection from 55.8 pb 1 (PRL ) Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

14 D /D Reult Comparion PDG CLEOc PDG B(D π ) B(CLEOc) B(PDG) previou abolute meaurement and PDG fit PDG CLEOc Br. Ratio(CLEOc) Br. Ratio(PDG) PDG B(D π π ) previou abolute meaurement and PDG fit Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

15 D Data Yield m(d ), D S S 788 ± 34 Event / 3 MeV Single Tag π m(d ), D π 3344 ± 77 Event / 3 MeV All double tag 2 m(d ) (GeV/c ) Double Tag m(d ) (GeV) m(d ), D π π 79 ± 54 π π Event / 3 MeV m(d ) (GeV) m(d ), D π π π 539 ± 41 π π π Event / 3 MeV m(d 2 ) (GeV/c ) All double tag Event / 8 MeV ignal 28 ideband m(d ) (GeV) m(d ) (GeV) m(d ) m(d ) (GeV) Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

16 D Sytematic Uncertaintie Source Fractional uncertainty (%) Tracking/ S /π.35/1.1/5. per particle Particle ID correlated by decay Reonant ubtructure 6. correlated by decay Fit procedure 3.5 in fit reult Event environment 3.5 in ππ Initial tate radiation correction 5 per ingle tag B(D π D ).7 in ππ, πππ Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

17 D Reult Preliminary Mode CLEOc (%) PDG 24 fit (%) B( S ) ± ±.55 B( π ) ± ± 1.2 B( π π ) ±.46 B(π π π ) ±.5 1. ±.28 S PDG 24 fit 1 CLEO Preliminary, 76 pb S PDG 24 fit PDG 24 fit, BR error only 1 CLEO Preliminary, 76 pb π π π π π π π π π π Branching Fraction (%) BF/PDG 24 fit Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

18 Abolute Branching Fraction Summary and Outlook D /D : Branching fraction from 56 pb 1 have preciion comparable to world average Updating to 281 pb 1 : we will be ytematiclimited Aiming for < 1.5% uncertainty on reference mode D : Preliminary abolute branching fraction for four D decay mode from 76 pb 1 of data Preciion about 11% for allcharged mode Incluive π π i a firt meaurement The meaured BF are conitent with the PDG 24 fit We are actively working on adding more mode (epecially decay with η, η ) We are aiming for < 4% uncertaintie with full CLEOc dataet Have more than 12 pb 1 additional data on tape Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

19 D /D (m)π ± (n)π (281 pb 1 ) Motivation: Cabibbouppreed BF badly known, in particular for mode with π Iopin analyi from D ππ probe final tate interaction Find reonant contribution and tune MC Single tag analyi provide full reach for thee low rate mode Branching ratio meaured relative to D π and D π π Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

20 D /D (m)π ± (n)π D D Shaded hitogram i normalized ideband Signal een in all channel except D π π π Peter Onyii CLEOc Charm Hadronic Decay Charm 26 2 / 37

21 D /D (m)π ± (n)π Mode B (1 3 ) PDG (1 3 ) π π 1.39 ±.4 ±.4 ±.3 ± ±.5 π π.79 ±.5 ±.6 ±.1 ±.1.84 ±.22 π π π 13.2 ±.2 ±.5 ±.2 ±.1 11 ± 4 π π π π 7.3 ±.1 ±.3 ±.1 ± ±.5 π π π π 9.9 ±.6 ±.7 ±.2 ±.1 π π π π π 4.1 ±.5 ±.2 ±.1 ±. ωπ π 1.7 ±.5 ±.2 ±. ±. ηπ.62 ±.14 ±.5 ±.1 ±.1 π π π <.35 (9% CL) ωπ <.26 (9% CL) ηπ π < 1.9 (9% CL) π π 1.25 ±.6 ±.7 ± ±.22 π π π 3.35 ±.1 ±.16 ± ±.4 π π π 4.8 ±.3 ±.3 ±.2 π π π π 11.6 ±.4 ±.6 ±.4 π π π π π 1.6 ±.18 ±.16 ± ±.23 ηπ 3.61 ±.25 ±.23 ± ±.6 ωπ <.34 (9% CL) For ππ decay, obtain amplitude ratio for A 2 ( I = 3/2) and A ( I = 1/2): A 2 A =.42±.14±.16 arg(a 2 /A ) = (86.4±2.8±3.3) (Error: tat, yt, normalizing mode, [CP correlation]) PRL 96, 8182 Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

22 D S,L π (281 pb 1 ) Uually aume B(D L X ) = B(D S X ) but thi i not trictly true... Can produce both Cabibboallowed and doublycabibbouppreed, and their amplitude for producing L and S interfere with oppoite ign; thu we expect L and S decay to have unequal rate (Bigi & Yamamoto, PL B349, 363) Interference effect tan 2 (θ C ) Expect B(D S π ) B(D L π ) by up to 1% Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

23 D S,L π Double tag analyi Tag D, find extra pion Form miing ma 2 of ret of ytem: fit for peak at kaon ma 2 independent of whether it L or S Careful undertanding of background hape required Combine with abolute D S π BF to form aymmetry Event / (.1 GeV ) Fit for D yield D yield in 1.86 < DMbc < 1.88: / beam contrained ma of D (GeV) Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

24 D S,L π Event / (.1 GeV^2 ) π π µ ν µ π S,L 3871 ± 71 π η Miing ma quared (GeV^2) B( S π ) B( L π ) = (3.55 ±.57 ±.158)% B( L π ) B( S π ) B( L π )B( S π ) =.1 ±.4 ±.7 B(D ηπ ) = (.391 ±.31 ±.33)% Preliminary Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

25 D /D /D (φ, η, η )X Incluive D /D branching fraction to meon with large content extremely poorly known D final tate have more content, hence expect larger η, η, φ branching fraction Incluive rate help dientangle decay chain through open charm ( e.g. undertand B from Υ(5S)) Ue 281 pb 1 for D /D and 71 pb 1 for D Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

26 D /D /D (φ, η, η )X Double tag: find D /D /D ; recontruct φ, η, η with remaining hower and track Ue φ, η γγ, η π π η π π γγ Ue ideband in E (D /D ) and m BC (D ) of the tag ide to get the background pectrum Fit invariant ma of φ and η, and η η ma difference Candidate / 2 MeV D η X (data) Signal tag 19.1 ± 5.3 Sideband tag no event η η ma difference (GeV) Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

27 D /D /D (φ, η, η )X Preliminary B(φX ) (%) B(ηX ) (%) B(η X ) (%) D 1. ±.1 ± ±.4 ± ±.2 ±.2 D 1.1 ±.1 ± ±.5 ±.5 1. ±.2 ±.1 D 15.1 ± 2.1 ± ± 5.6 ± ± 3.3 ± 1.2 η ignal include feeddown from η All except D /D φx are firt meaurement nown D excluive mode eentially aturate incluive meaurement Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

28 Summary Excellent detector, clean event, and large data ample branching fraction for open charm decay with preciion world average BF meaurement help normalize D and B phyic, probe trong interaction phyic CLEOc plan on taking 1.5 fb 1 of open charm data over the next two year, aim for abolute BF preciion of 1.5% for D, D and 4% for D Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

29 Backup Slide Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

30 Method Numeric Single tag yield: N i = N DD B i ɛ i Double tag yield: N ij = N DD B i B j ɛ ij Branching fraction: B j = N ij N i ɛ i ɛ ij In practice, we fit all the yield imultaneouly Maximize power: limiting tatitical uncertainty i total double tag in every mode Bad χ 2 omething wrong... Can correlate ytematic Obtain croection a well Peter Onyii CLEOc Charm Hadronic Decay Charm 26 3 / 37

31 Yield extraction DATA: π Single Tag Event / (.325 GeV ) m inv, D m(d ) (GeV/c ) π D Invariant ma (GeV) m v. m D D (D bkg = / (87., 87.7) Event / (.325 GeV ) bkgbar = / (86.6, 87.3) c1 =.98 / (.,.) 6 yield = / (52.9, 53.6) m inv, D yieldbar = / (54.1, ) π / D π D Invariant ma (GeV) DATA: π /π Double Tag π ) Fit ingle tag ignal with double Gauian or Crytal Ball function (parameter fixed from Monte Carlo) plu a linear background Each charge done eparately In double tag, count event in ignal and ideband boxe Combinatoric background i flat in m(d ) m(d ), ha tructure in m(d ) m(d ) m(d 2 ) (GeV/c ) Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

32 Background Nonpeaking background removed in the yield fit Peaking background are from crofeed between mode we conider, and contamination from other mode Latter dominated by Cabibbouppreed decay in S mode, e.g. prompt D 5π fake D S 3π; in ome mode up to 3% correction Etimate background to ingle and double tag with PDG branching fraction and efficiencie from MC, ubtract from meaured yield Fake type kpi Event / (.6 GeV ) MC 3x data yield = 228 ± Beam contrained ma (GeV) 15 DCSD decay D π faking D π in 3x MC ample. In data, contribute.15% of oberved peak. Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

33 Reonant Subtructure φ π Invariant ma (GeV) * Invariant ma (GeV) φ π Invariant ma (GeV) * π Invariant ma (GeV) m inv, D bkg = / (15., 15.8) 18 bkgbar = / (14., 14.8) c1 =.217 / (.1,.1) 16 yield = / (25.1, 25.8) 14 yieldbar = / (24.6, 25.4) m inv, D bkg = / (35.2, 35.9) bkgbar = / (35.2, 36.) 2 c1 =.175 / (.,.) 18 yield = / (27., 27.7) yieldbar = / (28.7, ) m inv, D bkg = / (19.6, 2.3) bkgbar = / (19.2, 2.1) 4 c1 =.11 / (.1,.1) yield = / (14.8, ) yieldbar = / (15.2, 15.9) m inv, D bkg = / (32.8, 33.7) bkgbar = / (33.4, 34.2) φ π Invariant ma (GeV) * Invariant ma (GeV) 5 c1 =.125 / (.,.) 5 yield = / (19.4, 2.) yieldbar = / (2.3, 2.6) φ π π Invariant ma (GeV) * π Invariant ma (GeV) Event / (.325 GeV ) m inv, D Event / (.325 GeV ) Our Monte Carlo ha ome reaonable mixture of intermediate reonance Our efficiencie depend on the intermediate tate We reweight the expected efficiencie by comparing data yield with MC expectation Size of correction i larget ytematic for π π The correction for a given mode affect that mode BF only Event / (.325 GeV ) Event / (.325 GeV ) Event / (.325 GeV ) m inv, D m inv, D m inv, D π Event / (.325 GeV ) Event / (.325 GeV ) Event / (.325 GeV ) Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

34 Sytematic tudie uing ψ Clean decay ψ J/ψ π π and J/ψ π π ued to compare tracking and π efficiencie in MC and data Recontruct J/ψ and one pion; compute recoil ma: peak at pion ma Find fraction of uch event with other pion recontructed Right: Plot for J/ψ π π,.15 < co θ π <.55 ɛ = (95.89 ±.2)%; agree with MC within tatitic Event / (.15 GeV ) Event / (.15 GeV ) piprime_data_new_cotheta_p_piprime.evt Fit parameter DATA 2nd π found igma2 =.1612 ± igma1 =.836 ± mpiq2 =.2214 ± mpiq1 =.1744 ± fract =.5 ± Npeak = 923 ± NBkgdExp = 98 ± M2mi (GeV) piprime_data_new_cotheta_p_nopiprime.evt Fit parameter DATA 2nd π not found p2 = 14.8 ± Npeak = 396 ± NBkgd = 457 ± NBkgdExp = 1. ± M2mi (GeV) Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

35 Production Channel We ue event with the topology e e D ± D D D (γ, π ). We do not recontruct the γ or π. We ue the momentum of the D candidate to elect for event with an intermediate D. (The quantity m BC = Ebeam 2 p2 D i a proxy for momentum.) We can ue a looe cut to include the daughter of D, or a tight cut for the directly produced D m BC, D S Direct D D from D MC mbcplt_4 m BC, D S Entrie 2178 Mean 2.2 RMS Data Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

36 The φπ problem φ π Invariant ma (GeV) φ π SIDEBAND Invariant ma (GeV) m inv, D bkg = / (15., 15.8) 18 bkgbar = / (14., 14.8) c1 =.217 / (.1,.1) 16 yield = / (25.1, 25.8) 14 yieldbar = / (24.6, 25.4) m inv, D bkg = 5.73 / (7.5, 8.3) 18 bkgbar = / (6.6, 7.4) c1 =.154 / (.2,.2) 16 yield = / (6.5, 7.2) 14 yieldbar = / (7.2, 7.9) 1 φ π Invariant ma (GeV) φ π SIDEBAND Entrie 2384 Mean 1.5e16 RMS Invariant ma (GeV) Event / (.325 GeV ) m inv, D Event / (.325 GeV ) Expect (f (98) )π to contribute to any φ ma region, with badly controlled parameter Correction might be on the order of 5% or more but depend on experiment ma window, reolution, angular ditribution requirement! Event / (.325 GeV ) helicity angle, phi band m inv, D khlangphi Event / (.325 GeV ) Looking at lowma pair (m() < 1.5 GeV) we ee evidence for calar production by looking at helicity angle helicity angle, low ma Peter Onyii CLEOc Charm Hadronic Decay Charm / 37

37 Comparion with BaBar φπ Can we compare with the BaBar B(D φπ ) reult? We can ue the PDG fit branching ratio... S PDG 24 fit 1 CLEO Preliminary, 76 pb S PDG 24 BR BaBar φπ 1 CLEO Preliminary, 76 pb π π π π π π π π π PDG 4: 3.6% Branching Fraction (%) We are more conitent with 3.6% than 4.8% π π π BaBar 5: 4.81% Branching Fraction (%) Peter Onyii CLEOc Charm Hadronic Decay Charm / 37