# Resonances in B D 0 D 0 Kdecay

- Slides: 23

Resonances in B+ D 0 D 0 K+decay for 400 fb-1 J. Brodzicka, H. Palka INP Kraków DC Meeting April 10 th, 2006

Dalitz plot projections for B + D 0 K+ with 20 Me. V binning For 1. 5 E-Mbc signal region Background ØDs. J(2700) is not split up Øno significant narow states are seen besides (3770) J. Brodzicka, H. Palka INP Krakow DC February 6 th, 2006 LR > 0. 01

B+ D 0 D 0 K+ candidates with D 0(’s) from the mass sideband D mass sideband: |M(D) - 1. 865 Ge. V| >15 Me. V (~2σ) at least one D from mass sideband no LR cut both D’s from mass sideband for Mbc > 5. 273 Ge. V (3 ) for E <20 Me. V (3 ) no peaking background J. Brodzicka, H. Palka INP Krakow DC April 10 th, 2006

B+ D 0 D 0 K+ candidates with D 0(’s) from the mass sideband at least one D from mass sideband both D from mass sideband for Mbc>5. 277 Ge. V (1. 5 ) for E <10 Me. V (1. 5 ) J. Brodzicka, H. Palka INP Krakow DC April 10 th, 2006

Two-body mass distributions for B+ D 0 D 0 K+ candidates with D 0(’s) from the mass sideband one D from mass sideband for Mbc > 5. 273 Ge. V (3 ) and E <20 Me. V (3 ) Mass spectra shapes consistent with background estimated from E-Mbc sideband J. Brodzicka, H. Palka INP Krakow DC April 10 th, 2006

Two-body mass distributions for B+ D 0 D 0 K+ candidates with D 0(’s) from the mass sideband both D from mass sideband J. Brodzicka, H. Palka INP Krakow for Mbc > 5. 273 Ge. V (3 ) and E <20 Me. V (3 ) DC April 10 th, 2006

Two-body mass distributions for B+ D 0 D 0 K+ candidates with D 0(’s) from the mass sideband one D from mass sideband for Mbc > 5. 277 Ge. V (1. 5 ) and E <10 Me. V (1. 5 ) J. Brodzicka, H. Palka INP Krakow DC April 10 th, 2006

Dalitz plot for B+ D 0 corrected D 0 K+ for acceptance ( with correction conserving number of events observed ) for Mbc > 5. 277 Ge. V and E <10 Me. V ( 1. 5 signal region ) ~2. 5 Ge. V Ds. J(2700) J. Brodzicka, H. Palka INP Krakow DC April 10 th, 2006

Dalitz plot for B+ D 0 corrected D 0 K+ for acceptance ( scaled to BF(B+ D 0 D 0 K+) by effective efficiency obtained ) for Mbc > 5. 277 Ge. V and E <10 Me. V ( 1. 5 signal region ) J. Brodzicka, H. Palka INP Krakow DC April 10 th, 2006

Mass distributions corrected for acceptance (using large ~700 K B+ D 0 D 0 K+ MC sample) Events from 1. 5 E-Mbc signal region Background from 6 < d <10 strip surrounding Mbc signal region J. Brodzicka, H. Palka INP Krakow DC April 10 th, 2006 the E-

Background-free invariant mass distributions corrected for acceptance B signal in mass bins obtained from 2 -dim Mbc- E fits in two-body inv. mass bins fitted B Signal corrected for acceptance J. Brodzicka, H. Palka INP Krakow DC April 10 th, 2006

B + D 0 K+ Dalitz plots for various decay models for MC studies based on the relative contributions from the resonant components and 3 -body decay obtained from data analysis (non coherent approach) How interference between Ds. J(2700) and (4160) (states crossing in the Dalitz plot) influences the Ds. J parametres Generated distributions no interference J. Brodzicka, H. Palka INP Krakow max constructive interf. max destructive interf. Ds. J(2700) and (4160) DC April 10 th, 2006

Comparison of mass spectra in various decay models for B+ D 0 D 0 K+ non-coherent approach no interference Generated distributions J. Brodzicka, H. Palka INP Krakow max constructive interf. = 0 between Ds. J(2700) and (4160) max destructive interf. = 180 between Ds. J(2700) and (4160) DC April 10 th, 2006

B + D 0 K+ Dalitz plots for various decay models for Reconstructed distributions no interference J. Brodzicka, H. Palka INP Krakow max constructive interf. max destructive interf. Ds. J(2700) and (4160) DC April 10 th, 2006

Comparison of mass spectra in various decay models non-coherent approach for B+ D 0 D 0 K+ no interference max constructive interf. between Ds. J(2700) and (4160) Reconstructed distributions J. Brodzicka, H. Palka INP Krakow max destructive interf. between Ds. J(2700) and (4160) DC April 10 th, 2006

Comparison of mass spectra in various decay models with data distributions data q interference effects do not influence the 2 -body mass distributions substantially q decay model is not decided J. Brodzicka, H. Palka INP Krakow non-coherent approach no interference max constructive interf. between Ds. J(2700) and (4160) max destructive interf. between Ds. J(2700) and (4160) DC April 10 th, 2006

Interference related systematics on Ds. J parameters Fits like in data analysis: for M(D 0 D 0)>3. 85 Ge. V (to remove (3770) reflection from high M(D 0 K+) region) BW + MC predicted (4160) reflection + non-resonant component described by 3 -body MC no interference max constructive interf. max destructive interf. Uncertainty on: Yield: +4 % M: +3 -8 Me. V Γ: +36 -30 Me. V J. Brodzicka, H. Palka INP Krakow DC April 10 th, 2006

Angular distribution in the Ds. J(2700) helicity frame Ds. J(2700) region: 2. 57 < M(D 0 K+) < 2. 84 Ge. V Comparison with the Ds. J(2700) spin hypotheses: J=1 2/n. d. f = 6. 7/5 ~cos 2θ J=2 2/n. d. f = 249. 9/5 ~(1 -3 cos 2θ)2 J=0 2/n. d. f = 184. 7/4 flat 1 - strongly favoured fitted B Signal corrected for acceptance J. Brodzicka, H. Palka INP Krakow DC April 10 th, 2006

Backups J. Brodzicka, H. Palka INP Krakow DC April 10 th, 2006

Dalitz plot and projections for For Mbc > 5. 277 Ge. V E <10 Me. V 1. 5 signal region ) Ds. J(2700) ( B + D 0 K+ Background: elliptical strip 6 to 10 in Mbc, E, surrounding the signal region (3770) (4160) Ds. J(2700) (4160) (3770) Ds. J(2700) (4160) (3770) J. Brodzicka, H. Palka INP Krakow LR > 0. 01 Ds. J(2700) (4160) (3770) DC February 6 th, 2006

Background-free invariant mass distributions 2 -dim Mbc- E fits in 2 -body inv. mass bins (3770) (4160) +Ds. J(2700) B signal in mass bins Ds. J(2700) + (4160) reflection Background-free mass spectra are very consistent with the Dalitz-plot projections over the estimated background. J. Brodzicka, H. Palka INP Krakow fitted B Signal DC February 6 th, 2006

Estimation of the resonance contributions Ds. J(2700) (3770) (4160) Z(3930) Breit Wigner functions + threshold function for (4160) in ½ helicity distr: 24 ± 11 events (~2σ) (for 2 nd half helicity distr: 20% smaller efficiency) for M(D 0 D 0)>3. 85 Ge. V (to remove (3770) reflection from high M(D 0 K+) region) Lower curve: MC predicted (4160) reflection + non-resonant component described by 3 -body MC Ds. J(2700) parameters consistent with previous estimations Non-resonant component yield: 47 ± 32 J. Brodzicka, H. Palka INP BAM February 27 th, 2006

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