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Resonances in decay Resonances in decay (for 400fb -1 ) (for 400fb -1 )BAM February 27th, 2006 J.Brodzicka, H.Palka INP Kraków J.Brodzicka, H.Palka INP.

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Presentation on theme: "Resonances in decay Resonances in decay (for 400fb -1 ) (for 400fb -1 )BAM February 27th, 2006 J.Brodzicka, H.Palka INP Kraków J.Brodzicka, H.Palka INP."— Presentation transcript:

1 Resonances in decay Resonances in decay (for 400fb -1 ) (for 400fb -1 )BAM February 27th, 2006 J.Brodzicka, H.Palka INP Kraków J.Brodzicka, H.Palka INP Kraków B +  D 0 D 0 K + B +  D 0 D 0 K + Outline :  B +  D 0 D 0 K + for  400fb -1  Dalitz plot and projections  Background-free 2-body mass distributions  Fits to mass distributions, the D sJ (2700) and charmonia parameters  Angular distrbutions  Conclusions

2  B+  D0D0K+ B+  D0D0K+ B+  D0D0K+ B+  D0D0K+ J.Brodzicka, H.Palka INP BAM February 27th, 2006 LR>0.01 LR>0.01 for  E  <20MeV ~ 3  for M bc >5.273GeV ~ 3  Fitting method: 2-dimensional unbinned likelihood fit on the M bc vs.  E plane Signal Bckgd. :399 ± 40 ~1500 400 fb -1 : 399 ± 40 ~1500 ( 250 : ( 250 fb -1 : 234 ± 30 ~ 900 BF = (1.25 ± 0.16 + 0.16 )  10 -3 – 0.27 BF = (1.31 ± 0.13 + 0.17 )  10 -3 – 0.27

3 Dalitz-plot projections for Background: elliptical strip 6  to 10  in Mbc,  E, surrounding the signal region B +  D 0 D 0 K + For Mbc > 5.277GeV  E  <10 MeV ( ~1.5  M bc,  E signal region ) LR > 0.01  (3770)  (4160) D sJ (2700)  (3770)  (4160)  (3770)  (4160) D sJ (2700) for 400fb -1 for 250fb -1 J.Brodzicka, H.Palka INP BAM February 27th, 2006

4 Background-free invariant mass distributions Background-free invariant mass distributions 2-dim M bc -  E fits in 2-body inv. mass bins B signal in mass bins D sJ (2700) +  (4160) reflection  (4160) + D sJ (2700) reflection  (3770) Background-free mass spectra are very consistent with the Dalitz-plot projections over the estimated background. fitted B Signal J.Brodzicka, H.Palka INP BAM February 27th, 2006

5 Estimation of the resonance contributions  (4160)  (3770) D sJ (2700) (to remove  (3770) reflection from high M( D 0 K + ) region) for M(D 0 D 0 )>3.85 GeV Lower curve: MC predicted  (4160) reflection + non-resonant component described by 3-body MC for  (4160) in ½ helicity distr: 24 ± 11 events (~2σ) (for 2nd half helicity distr:  20% smaller efficiency) Breit Wigner functions + threshold function D sJ (2700) parameters consistent with previous estimations Z (3930) J.Brodzicka, H.Palka INP BAM February 27th, 2006 Non-resonant component yield : 47 ± 32

6 Contributions from quasi-two-body components: (normalized to measured yields and superimposed by adding histograms) B+  (4160) K+ B+  (3770) K+ B+  D 0 D sJ + (2700) Explanation of 2-body mass spectra Shapes predicted by MC simulations D sJ + (2700),  (3770) are not the full story, but the ‘fit’ is acceptable J.Brodzicka, H.Palka INP BAM February 27th, 2006

7 Background-free mass distr. corrected for acceptance M(D 0 D 0 ) strongly affected by acceptance losses  M(D 0 D 0 ) strongly affected by acceptance losses  influence of these losses on D sJ (2700) region is minor B+  (4160) K+ B+  (3770) K+ B+  D 0 D sJ + (2700)  (3770) D sJ (2700) Z (3930) J.Brodzicka, H.Palka INP BAM February 27th, 2006

8 Angular distributions in the helicity frames of DsJ(2700) and  (3770) D sJ (2700) region: 2.5 < M(D 0 K + ) < 2.9 GeV  (3770) region: M(D 0 D 0 ) < 3.85 GeV Background-free cos  distributions obtained using 2-dim M bc -  E fit in each cos  bin  (4160) reflection fitted B Signal corrected for acceptance D sJ (2700) spin hypotheses: J=1  2 /n.d.f = 3.4/4 J=2  2 /n.d.f = 16.2/4 J=0  2 /n.d.f = 36.5/4  (3770) spin hypothesis: J=1  2 /n.d.f = 3.5/5 1 - favoured J.Brodzicka, H.Palka INP BAM February 27th, 2006

9 Summary 400 fb -1 sample has been analysed;  400 fb -1 sample has been analysed; all features seen in the 250 fb -1 sample are confirmed all features seen in the 250 fb -1 sample are confirmed  strong D sJ (2700) → D 0 K + resonance (significance = 6.7σ) M= 2709 ± 10 MeV Γ= 137 ± 27 MeV J P =1 - favoured M= 2709 ± 10 MeV Γ= 137 ± 27 MeV J P =1 - favoured  Ψ(3770) confirmed M= 3777 ± 3 MeV Γ= 27 ± 9 MeV M= 3777 ± 3 MeV Γ= 27 ± 9 MeV  remaining structures in M(D 0 D 0 ) could not be resolved, but their influence on the D sJ (2700) parameters is small but their influence on the D sJ (2700) parameters is small (included into systematic errors) (included into systematic errors)  We would like to publish D sJ (2700) as it is now, deeper insight into M(D 0 D 0 ) and M(D 0 K + ) dynamics deeper insight into M(D 0 D 0 ) and M(D 0 K + ) dynamics will be possible after full Dalitz plot analysis (if it is successful) will be possible after full Dalitz plot analysis (if it is successful) J.Brodzicka, H.Palka INP BAM February 27th, 2006

10 Backups

11 Dalitz plot and projections for Background: elliptical strip 6  to 10  in Mbc,  E, surrounding the signal region B +  D 0 D 0 K + For Mbc > 5.277GeV  E  <10 MeV ( 1.5  signal region ) LR > 0.01  (4160)  (3770) D sJ (2700) D sJ (2700)  (3770)  (4160) D sJ (2700)  (3770)  (4160)  (3770)  (4160) D sJ (2700) J.Brodzicka, H.Palka INP BAM February 27th, 2006

12 Dalitz plot projections for with smaller 20MeV binning Background B +  D 0 D 0 K + For 1.5   E-Mbc signal region LR > 0.01 for 400fb -1  no significant narow states J.Brodzicka, H.Palka INP BAM February 27th, 2006

13 Acceptance losses over the Dalitz plot Efficiency map for B +  D 0 D 0 K + D 0  Kπ D 0  Kπ, K3π, Kππ 0, K s ππ, KK [10 -3 ] [10 -3 ] Acceptance corrections for mass distributions W acc = N rec (M)/N gen (M) W acc = N rec (M)/N gen (M) J.Brodzicka, H.Palka INP BAM February 27th, 2006

14 Mass distributions corrected for acceptance Events from 1.5   E-Mbc signal region Background J.Brodzicka, H.Palka INP BAM February 27th, 2006

15 Angular distribution in the helicity frame of DsJ(2700) fitted B Signal corrected for acceptance Comparison with the D sJ (2700) spin hypotheses: J=1  2 /n.d.f = 3.4/4 J=2  2 /n.d.f = 16.2/4 J=0  2 /n.d.f = 36.5/4

16 Explanation of 2-body mass spectra with no ψ(4160) contribution D sJ (2700) N DsJ = 231 ± 32 M DsJ = 2706 ± 9 MeV Γ DsJ = 136 ± 25 MeV

17 J.Brodzicka, H.Palka INP BAM February 27th, 2006

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19 Systematic error contributions to BF () Systematic error contributions to BF (B +  D 0 D 0 K + )


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