Presentation is loading. Please wait.

Presentation is loading. Please wait.

Hadronic Moments in Semileptonic B Decays Ramon Miquel Lawrence Berkeley National Laboratory (for the CDF II Collaboration)

Published by Modified over 9 years ago

Similar presentations

Presentation on theme: "Hadronic Moments in Semileptonic B Decays Ramon Miquel Lawrence Berkeley National Laboratory (for the CDF II Collaboration)"— Presentation transcript:

1 Hadronic Moments in Semileptonic B Decays Ramon Miquel Lawrence Berkeley National Laboratory (for the CDF II Collaboration)

2 7/2/04Ramon Miquel BEACH 042 F theory evaluated using OPE in HQET: expansion in  s and 1/m B powers: O(1/m B )  1 parameter:  (Bauer et al., PRD 67 (2003) 071301) O(1/m B 2 )  2 more parameters: 1, 2 O(1/m B 3 )  6 more parameters:  1,  2, T 1-4 Motivation (I)  (4S), LEP/SLD, CDF measurements. Experimental  |V cb |~1% Theory with pert. and non-pert. corrections.  |V cb |~2.5% Most precise determination of V cb comes from  sl (“inclusive” determination):

3 7/2/04Ramon Miquel BEACH 043 Motivation (II) Hadronic moments: B  X c l, recoil mass M(X c ) Leptonic moments: B  X c l, lepton E in B rest frame Photonic moments: Photon energy in b  s  (CLEO, DELPHI, BABAR) (CLEO) (CLEO, DELPHI, BABAR, CDFII) Many inclusive observables can be written using the same expansion (same non-perturbative parameters): the spectral moments: Constrain the unknown non-pert. parameters and reduce |V cb | uncertainty. With enough measurements: test of underlying assumptions (duality…).

4 7/2/04Ramon Miquel BEACH 044 What is X c ?  ~25% of semi-leptonic width is poorly known Higher mass states: D**Semi-leptonic widths (PDG 03): Br (%) B +  X c l 10.89  0.26 B +  D* l 6.00  0.24 B +  D l 2.23  0.15 (b/B + /B 0 combination, b  u subtracted) Possible D’  D ( * )  contributions neglected: No experimental evidence so far DELPHI limit: We assume no D’ contribution in our sample

5 7/2/04Ramon Miquel BEACH 045 Analysis Strategy Typical mass spectrum M(X 0 c ) (Monte Carlo): D 0 and D* 0 well-known  measure only f**  only shape needed 1) Measure f**(s H ) 2) Correct for background, acceptances, bias  moments of D** 3) Add D and D*  M 1,M 2 4) Extract , 1

6 7/2/04Ramon Miquel BEACH 046 Channels −D **0  D +   OK –D **0  D 0  0 Not reconstructed. Half the rate of D +   –D **0  D *+   D *+  D 0  + OK D *+  D +  0 Not reconstructed. Feed-down to D +   –D **0  D *0  0 Not reconstructed. Half the rate of D *+   Must reconstruct all channels to get all the D ** states.  However CDF has limited capability for neutrals B 0  D **  l + always leads to neutral particles  ignore it B -  D **0 l  better, use isospin for missing channels:

7 7/2/04Ramon Miquel BEACH 047 D **0 D *+  **- D 0  *+ (Br=67.7%) K -  + (Br=3.8%) K -  +  -  + (Br=7.5%) K -  +  0 (Br=13.1%) Event Topology Exclusive reconstruction of D ** : D **0 D +  **- K -  +  + (Br=9.1%) “D + ”“D* + ”

8 7/2/04Ramon Miquel BEACH 048 Backgrounds Combinatorial background under the D ( * ) peaks:  sideband subtraction Physics background: B  D ( * )+ D s , D (s)  Xl  MC, subtracted Prompt pions faking  **: fragmentation underlying event  separate B and primary vertices (kills also prompt charm)  use impact parameters to discriminate  model: wrong-sign  ** +  combinations Feed-down in signal: D** 0  D* + (  D +  0 )   irreducible background to D** 0  D +  .  subtracted using data:  shape from D 0   in D** 0  D* + (  D 0  + )    rate: ½ (isospin) x eff. x BR

9 7/2/04Ramon Miquel BEACH 049 Lepton + D ( * )+ Reconstruction Lepton + D ( * )+ : D vertex: 3D l+D(+  * ) vertex (“B”): 3D L xy (B) > 500  m M(B) < 5.3 GeV Data Sample: e/  + displaced track ~ 180 pb -1 (  Sept 2003) Track Selection: e/  : p T > 4 GeV other: p T > 0.4 GeV Total: ~ 28000 events

10 7/2/04Ramon Miquel BEACH 0410  ** Selection Based on topology: impact parameter significances w.r.t. primary, B and D vertices  ** 3D IP signif. wrt BV  ** 2D IP signif. wrt PV p T > 0.4 GeV  R < 1.0 |d 0 PV /  | > 3.0 |d 0 BV /  | < 2.5 |d 0 DV /  | > 0.8 L xy B  D > 500  m Cuts are optimized using MC and background data: Additional cuts only for D + :

11 7/2/04Ramon Miquel BEACH 0411 Raw m** Distribution Measured in  m**, shifted by M(D ( * )+ ), side-band subtracted. D 1,D 1 *,D 2 * D 2 *,D 0 * Feed-down

12 7/2/04Ramon Miquel BEACH 0412 Efficiency Corrections 1) Correct the raw mass for any dependence of  reco on M(D**): Possible dependence on the D** species (spin). Monte-Carlo for all D** (Goity-Roberts for non-resonant), cross-checked with pure phase space decays. 2) Cut on lepton energy in B rest frame: Theoretical predictions need well-defined p l * cut. We can’t measure p l *, but we can correct our measurement to a given cut:  p l * > 700 MeV/c.

13 7/2/04Ramon Miquel BEACH 0413 Corrected Mass and D** Moments Procedure: Unbinned procedure using weighted events. Assign negative weights to background samples. Propagate efficiency corrections to weights. Take care of the D + / D* + relative normalization. Compute mean and sigma of distribution. Results: No Fit !

14 7/2/04Ramon Miquel BEACH 0414 Final Results Pole mass scheme 1S mass scheme 0.61 0.69

15 7/2/04Ramon Miquel BEACH 0415 Systematic Errors  m 1 (GeV 2 )  m 2 (GeV 4 )  M 1 (GeV 2 )  M 2 (GeV 4 )  (GeV)  1 (GeV 2 ) Stat.0.160.690.0370.250.0750.055 Syst.0.080.200.0650.120.0900.082 Mass resolution0.020.130.0050.040.0120.009 Eff. Corr. (data)0.030.130.0060.050.0140.011 Eff. Corr. (MC)0.060.050.0160.030.0170.006 Bkgd. (scale)0.010.030.0020.010.0030.002 Physics bkgd.0.010.020.0020.010.0040.002 D + / D *+ BR0.010.020.0020.010.0040.002 D + / D *+ Eff.0.020.030.0040.010.0050.002 Semileptonic BRs0.0620.100.0640.022 11 0.0410.069 TiTi 0.0320.031 ss 0.0180.007 m b, m c 0.0010.008 Choice of p l * cut0.0190.009

16 7/2/04Ramon Miquel BEACH 0416 Comparison with Previous Measurements Pole mass scheme

17 7/2/04Ramon Miquel BEACH 0417 Summary First measurement of hadronic moments in semileptonic B decays performed at a hadron collider. Good agreement with HQET and previous determinations. Competitive with other experiments. Little model dependency. No assumptions on shape or rate of D** components. Increased statistics and improved tracking will lead to substantially more precise results in the near future.

18 BACK-UP SLIDES

19 7/2/04Ramon Miquel BEACH 0419 CKM and V cb | V cb | = A 2 (defines the scale of UT)

20 7/2/04Ramon Miquel BEACH 0420 |V cb | from inclusive B decays Experiment: large statistics on BR(B  X c - ) and  B and small systematics V cb measurements |V cb | from exclusive B decays Large statistics on B d 0  D (*) - available and new measurements are coming Present precision (5%) is systematics limited : Experiments: D** states, D’s BR Theory: form factor extrapolation, corrections to F (1)=1 can be reduced in the future |V cb | excl =(42.1  1.1 exp  1.9 theo )  10 -3 (PDG 2002, V cb review) |V cb | incl = (40.4 ± 0.5 exp ± 0.5 , ± 0.8 theo )  10 -3 (PDG 2002, V cb review)

21 7/2/04Ramon Miquel BEACH 0421 Lepton + D Reconstruction Lepton + D ( * )+ : D vertex: 3D l+D(+  * ) vertex (“B”): 3D L xy (B) > 500  m L xy (D /B ) > -200  m m(B) < 5.3 GeV Data Sample: e/  + displaced track ~ 180 pb -1 (  Sept 2003) Track Selection: e/  : p T > 4 GeV other: p T > 0.4 GeV

22 7/2/04Ramon Miquel BEACH 0422 D* + Reconstruction and Yields D* + channels:  m*  M(D 0  * ) – M(D 0 ) D ( * )+ l  (+cc)   yields: ~ 28000 events

23 7/2/04Ramon Miquel BEACH 0423 Monte-Carlo Validation (I) K , e K , e K ,  K  0, e K ,  K , e MC vs. semileptonic sample: Matching  2 probability for those plots: 67%74%23% 43%69%87%

24 7/2/04Ramon Miquel BEACH 0424 Monte-Carlo Validation (II) Relative yield prediction K3  /K  : (cross-check) R data = 0.77±0.02 R pred = 0.80±0.04 R pred /R data = 1.04±0.06  efficiency for adding tracks understood Relative yield prediction K2  /K  : (needed for D + /D* normalization) Two methods (a,b) to derive this BR a)Based on inclusive b  D (*)+ l b)Based on exclusive B  D (*)+ l, D ** l + PDG BR + MC efficiency ratios  uncertainties in Br (incl.) and D** spectroscopy (excl.) compromise prediction  1. – 0.87 = 13% used as systematics R data R pred R pred /R data 3.71±0.083.31±0.580.89±0.16 3.71±0.083.23±0.290.87±0.08

25 7/2/04Ramon Miquel BEACH 0425 Impact Parameters in MC Comparison data/MC for IP: (worst case) KK  ** 2D IP signif. wrt PV KK  ** 3D IP signif. wrt BV Residual corrections: derived from data:  * non-SVT D daughters (p T > 1.5 GeV) corrections from double ratios in p T in m**

26 7/2/04Ramon Miquel BEACH 0426 Background Subtraction Use mass side-bands to subtract combinatorial background. Use D* + [  D 0  + ]   to subtract feed-down from D* + [  D +  0 ]   to D +  . Use wrong-sign  ** + l  combinations to subtract prompt background to  **. –Possible charge asymmetry of prompt background studied with fully reconstructed B’s: 4% contribution at most. Possible D’  D ( * )  contributions neglected: –No experimental evidence so far. –DELPHI limit: We assume no D’ contribution in our sample

27 7/2/04Ramon Miquel BEACH 0427 Combination with D 0, D* 0 Take M(D 0 ), M(D* 0 ),  sl,  0,  * from PDG 2003 : −  sl  0,  * are obtained combining BR’s for B , B 0 and admixture, assuming the widths are identical (not the BR’s themselves), and using f  / f 0 = 1.04 ± 0.08  (B  ) /  (B 0 ) = 1.085 ± 0.017 –Results: BR(B +  X 0 c l + l ) = 0.1089 ± 0.0026 BR(B +  D 0 l + l ) = 0.0223 ± 0.0015 BR(B +  D* 0 l + l ) = 0.0600 ± 0.0024

28 7/2/04Ramon Miquel BEACH 0428 Main Systematics Semileptonic branching ratios when combining D** with D and D* Efficiency corrections from data − Use data-corrected efficiency. vs. pure MC efficiency Efficiency corrections from D** Monte-Carlo − D** states + NR Goity-Roberts vs. pure phase-space Mass resolution: − Dominated by satellite: ± 60 MeV Prompt background scale − Charge correlations WS / RS: ± 4% Other: D + /D* normalization, physics, p l * cut, theory…

Download ppt "Hadronic Moments in Semileptonic B Decays Ramon Miquel Lawrence Berkeley National Laboratory (for the CDF II Collaboration)"

Similar presentations

14 Sept 2004 D.Dedovich Tau041 Measurement of Tau hadronic branching ratios in DELPHI experiment at LEP Dima Dedovich (Dubna) DELPHI Collaboration E.Phys.J.

14 Sept 2004 D.Dedovich Tau041 Measurement of Tau hadronic branching ratios in DELPHI experiment at LEP Dima Dedovich (Dubna) DELPHI Collaboration E.Phys.J.
Studies of open heavy flavour production at LHCb Artur Ukleja (The Andrzej Sołtan Institute for Nuclear Studies, Warsaw) on behalf of the LHCb Collaboration.

Studies of open heavy flavour production at LHCb Artur Ukleja (The Andrzej Sołtan Institute for Nuclear Studies, Warsaw) on behalf of the LHCb Collaboration.
Measuring the bb cross- section using B  D o X   decays Liming Zhang & Sheldon Stone Syracuse University.

Measuring the bb cross- section using B  D o X   decays Liming Zhang & Sheldon Stone Syracuse University.
Study of B  D S ( * )  D*  *   and D ( * ) (4  )   at CLEO Jianchun Wang Syracuse University Representing The CLEO Collaboration DPF 2000 Aug 9.

Study of B  D S ( * )  D*  *   and D ( * ) (4  )   at CLEO Jianchun Wang Syracuse University Representing The CLEO Collaboration DPF 2000 Aug 9.
Determination of and related results from B A B AR Masahiro Morii, Harvard University on behalf of the B A B AR Collaboration |V cb | MESON 2004, Krakow,

Determination of and related results from B A B AR Masahiro Morii, Harvard University on behalf of the B A B AR Collaboration |V cb | MESON 2004, Krakow,
ICFP 2005, Taiwan Colin Gay, Yale University B Mixing and Lifetimes from CDF Colin Gay, Yale University for the CDF II Collaboration.

ICFP 2005, Taiwan Colin Gay, Yale University B Mixing and Lifetimes from CDF Colin Gay, Yale University for the CDF II Collaboration.
Radiative B Decays (an Experimental Overview) E.H. Thorndike University of Rochester CLEO Collaboration FPCP May 18, 2002.

Radiative B Decays (an Experimental Overview) E.H. Thorndike University of Rochester CLEO Collaboration FPCP May 18, 2002.
Current Methods of determining V ub I. Endpoint of the inclusive lepton spectrum II. Exclusive decays Methods of determining V ub with small theoretical.

Current Methods of determining V ub I. Endpoint of the inclusive lepton spectrum II. Exclusive decays Methods of determining V ub with small theoretical.
Sep. 29, 2006 Henry Band - U. of Wisconsin 1 Hadronic Charm Decays From B Factories Henry Band University of Wisconsin 11th International Conference on.

Sep. 29, 2006 Henry Band - U. of Wisconsin 1 Hadronic Charm Decays From B Factories Henry Band University of Wisconsin 11th International Conference on.
Recent Electroweak Results from the Tevatron Weak Interactions and Neutrinos Workshop Delphi, Greece, 6-11 June, 2005 Dhiman Chakraborty Northern Illinois.

Recent Electroweak Results from the Tevatron Weak Interactions and Neutrinos Workshop Delphi, Greece, 6-11 June, 2005 Dhiman Chakraborty Northern Illinois.
1 Inclusive B Decays - Spectra, Moments and CKM Matrix Elements Presented by Daniel Cronin-Hennessy University of Rochester (CLEO Collaboration) ICHEP.

1 Inclusive B Decays - Spectra, Moments and CKM Matrix Elements Presented by Daniel Cronin-Hennessy University of Rochester (CLEO Collaboration) ICHEP.
Heavy Flavor Production at the Tevatron Jennifer Pursley The Johns Hopkins University on behalf of the CDF and D0 Collaborations Beauty 2006 - University.

Heavy Flavor Production at the Tevatron Jennifer Pursley The Johns Hopkins University on behalf of the CDF and D0 Collaborations Beauty University.
1 V cb : experimental and theoretical highlights Marina Artuso Syracuse University.

1 V cb : experimental and theoretical highlights Marina Artuso Syracuse University.
CHARM 2007, Cornell University, Aug. 5-8, 20071Steven Blusk, Syracuse University D Leptonic Decays near Production Threshold Steven Blusk Syracuse University.

CHARM 2007, Cornell University, Aug. 5-8, 20071Steven Blusk, Syracuse University D Leptonic Decays near Production Threshold Steven Blusk Syracuse University.
Search for B     with SemiExclusive reconstruction C.Cartaro, G. De Nardo, F. Fabozzi, L. Lista Università & INFN - Sezione di Napoli.

Search for B     with SemiExclusive reconstruction C.Cartaro, G. De Nardo, F. Fabozzi, L. Lista Università & INFN - Sezione di Napoli.
1 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results ALEPH Results on  Branching Ratios and Spectral Functions Michel Davier Laboratoire.

1 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results ALEPH Results on  Branching Ratios and Spectral Functions Michel Davier Laboratoire.
Alex Smith – University of Minnesota Determination of |V cb | Using Moments of Inclusive B Decay Spectra BEACH04 Conference June 28-July 3, 2004 Chicago,

Alex Smith – University of Minnesota Determination of |V cb | Using Moments of Inclusive B Decay Spectra BEACH04 Conference June 28-July 3, 2004 Chicago,
Jochen Dingfelder, SLAC Semileptonic Decay Studies with B A B AR Annual DOE HEP Program Review, June 5-8, 2006, SLAC B D   X c,X u.

Jochen Dingfelder, SLAC Semileptonic Decay Studies with B A B AR Annual DOE HEP Program Review, June 5-8, 2006, SLAC B D   X c,X u.
Study of the semileptonic decays at 4170 MeV Koloina Randrianarivony Marina Artuso (Syracuse University)

Study of the semileptonic decays at 4170 MeV Koloina Randrianarivony Marina Artuso (Syracuse University)
Preliminary Measurement of the BF(   → K -  0  ) using the B A B AR Detector Fabrizio Salvatore Royal Holloway University of London for the B A B AR.

Preliminary Measurement of the BF(   → K -  0  ) using the B A B AR Detector Fabrizio Salvatore Royal Holloway University of London for the B A B AR.

Similar presentations

Ads by Google