170 likes | 280 Views
D sJ (2700) in decay J.Brodzicka, H.Palka INP Krak ó w DC June 12 , 2006. B + D 0 D 0 K +. How to describe M(D0K+) distribution?. M(D 0 K + ) for M(D 0 D 0 )>3 . 85 GeV to remove (3770) r eflection from high M( D 0 K + ) region. previous fit:.
E N D
DsJ(2700) in decay J.Brodzicka, H.Palka INP Kraków DC June12, 2006 B+ D0D0K+
How to describe M(D0K+) distribution? M(D0K+)for M(D0D0)>3.85GeVto remove (3770)reflection from high M(D0K+) region previous fit: now: + scalar exponential component BW + MC predicted (4160)reflection + non-resonantcomponent described by 3-body MC 3-body PS: 47 ± 32 J.Brodzicka, H.Palka INP DCJune12, 2006
M(D0K+) corrected for acceptance Fit: BW + MC predicted (4160)reflection + exp[-A * M(D0K+) ] + non-resonantcomponent described by 3-body MC Physics interpretation of this exponential component? J.Brodzicka, H.Palka INP DCJune12, 2006
B+ (4160)K+ B+ (3770)K+ B+ D0DsJ+(2700) exp. component Explanation ofeff. corrected2-body mass spectra Contribution from each component: normalized to measured yield and superimposed by adding histograms – non coherent approach Shapes predicted by MC simulations J.Brodzicka, H.Palka INP DCJune12, 2006
B+ (4160)K+ B+ (3770)K+ B+ D0DsJ+(2700) exp. component Explanation of2-body mass spectra Shapes predicted by MC simulations J.Brodzicka, H.Palka INP DCJune12, 2006
B+ D0D0K+ Dalitz plots for various decay models for How interference between DsJ(2700)and scalar exp. component influences the DsJ parametres? MC studies based on the relative intensitiesof contributing components obtained from data analysis (non coherent approach) no interference max constructive interf. max destructive interf. J.Brodzicka, H.Palka INP DCJune12, 2006
non-coherent approach no interference max constructive interf. between DsJ(2700)and exp max destructive interf. between DsJ(2700)exp Decay model predictions vs. observed mass spectra • interference effects do not influence DsJ parameters strongly • decay model is not decided (included in systematics) • look at angular distributions is needed J.Brodzicka, H.Palka INP DCJune12, 2006
for uncorrected distributions no interference max constructive interf. max destructive interf. J.Brodzicka, H.Palka INP DCJune12, 2006
Backups J.Brodzicka, H.Palka INP DCJune12, 2006
Comparison with the DsJ(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 fitted B Signal corrected for acceptance 1-favoured Angular distribution in the helicity frame of DsJ(2700) Background-free cos distribution obtained using 2-dim Mbc-E fit in eachcos bin DsJ(2700) →D0K+ : 1→0-0-P-wave decay thusDsJ(2700) P parity : - J.Brodzicka, H.Palka INP BAM February 27th, 2006
B+ (4160)K+ B+ (3770)K+ B+ D0DsJ+(2700) DsJ+(2700), (3770) are not the full story, but the ‘fit’ is acceptable Explanation of2-body mass spectra Contributions from quasi-two-body components: (normalized to measured yields and superimposed by adding histograms) Shapes predicted by MC simulations J.Brodzicka, H.Palka INP BAM February 27th, 2006
B+ (4160)K+ B+ (3770)K+ B+ D0DsJ+(2700) Background-free mass distr. corrected for acceptance (3770) DsJ(2700) Z(3930) • M(D0D0) strongly affected by acceptance losses • influence of these losses on DsJ(2700) regionis minor J.Brodzicka, H.Palka INP BAM February 27th, 2006
DsJ(2700) (3770) (4160) DsJ(2700) (4160) (3770) DsJ(2700) (4160) (4160) (3770) DsJ(2700) (3770) Dalitz plot and projections for B+ D0D0K+ LR > 0.01 For Mbc > 5.277GeV E<10 MeV( 1.5 signal region ) Background:elliptical strip 6 to 10 in Mbc, E, surrounding the signal region J.Brodzicka, H.Palka INP BAM February 27th, 2006
Events from 1.5E-Mbc signal region Background Mass distributions corrected for acceptance J.Brodzicka, H.Palka INP BAM February 27th, 2006
Dalitz plot projections for with smaller 20MeV binning B+ D0D0K+ LR > 0.01 For 1.5E-Mbc signal region Background for 400fb-1 no significant narow states J.Brodzicka, H.Palka INP BAM February 27th, 2006
Summary • 400 fb-1 sample has been analysed; all features seen in the 250 fb-1 sample are confirmed • strong DsJ(2700)→D0K+resonance(significance = 6.7σ) M= 2709 ± 10 MeV Γ= 137 ± 27 MeV JP=1- favoured • Ψ(3770) confirmed M= 3777 ± 3 MeV Γ= 27 ± 9 MeV • remaining structures in M(D0D0) could not be resolved, but their influence on the DsJ(2700) parameters is small (included into systematic errors) • We would like to publish DsJ(2700) as it is now, deeper insight into M(D0D0) and M(D0K+) dynamics will be possible after full Dalitz plot analysis (if it is successful) J.Brodzicka, H.Palka INP BAM February 27th, 2006