on quasi-two-body components of (for 250fb -1 ) (for 250fb -1 ) j.brodzicka, h.palka inp krakow dc...

On quasi-two-body components On quasi-two-body components ofof

(for 250fb(for 250fb-1-1))

J.Brodzicka, H.Palka INP Krakow DC Meeting May 16, J.Brodzicka, H.Palka INP Krakow DC Meeting May 16, 20052005

BB++ D D00DD00KK++

Looser LR cut applied Looser LR cut applied LR>0.01LR>0.01 ( ( previously LR>0.04 previously LR>0.04 S=151 ± 18 S=151 ± 18 ) )


BB++ D D00DD00KK++

S = S = 234234 ±± 3030

SS/B = 0.25/B = 0.25

N/7

MeV

E

for Mbc >5.273 GeV (3) N

/2.5

MeV

Mbc

for E<15MeV (3)

Fitting method: 2-dim Mbc vs. E unbinned likelihood fit

BF=(1.25 ± 0.16 + 0.26 ) 10-3 – 0.16


Dalitz plot and projections for Background: elliptical strip 6 to 10

in Mbc, E, surrounding the signal region

B+ D0D0K+

For Mbc > 5.277 GeV E<7.5 MeV

( 1.5 signal region )

LR > 0.01

N /

50M

eV

M( D0 K+ )

N /

50M

eV

M( D0K+ )

N /

50M

eV

M( D0D0 )M2( D0K+ )

M2(

D0D

0 )


Background-free invariant mass distributions2-dim Mbc vs. E fits in 2-body inv. mass bins B signal in mass bins

DsJ(2700) +(4160) reflection

(4160) +DsJ(2700) reflection

(3770)

Sig

nal /

50

MeV

M( D0D0 )M( D0 K+ ) M( D0K+ )

Sig

nal /

50

MeV

Sig

nal /

50

MeV

fitted B Signal

Background-free spectra are very consistent with the Dalitz-plot projections over the estimated background.

Estimation of the resonance contributionsEstimation of the resonance contributions


M( D0 K+ )M( D0D0 )M( D0D0 )

Sig

nal /

25

MeV

Sig

nal /

50

MeV

Sig

nal /

50

MeV

(4160) in ½ helicity distr. 33.9 ± 6.1 events

.0cos DDfor

total (4160) yield: 61 ± 11(for 2nd half helicity distr: 20% smaller eff. )

(to remove (3770)reflection

from high D0K+ mass region)

for M(D0D0)>3.85 GeV

(4160)(3770) DsJ(2700)

Lower curve in the fit:MC predicted reflection from (4160) (normalized to 61) + non-resonant componentdescribed by 3-body MC Phase Space

fitted B Signal

Result of fits to background-free 2-body mass spectra


Non-resonant component yield: NNR = 37 ± 13


Sig

nal /

50

MeV

Sig

nal /

50

MeV

Sig

nal /

50

MeV

M( D0D0 )M( D0 K+ ) M( D0K+ )

Explanation of 2-body mass spectraContributions from quasi-two-body components:(normalized to measured yields and superimposed by adding histograms)

(Shapes predicted by MC simulations generated with parameters of contributing resonances obtained in the analysis)

B+ (4160) K+

B+ (3770) K+

B+ D0 DsJ+(2700)

2/n.d.f =20/21 2/n.d.f =18/21 2/n.d.f =24/22


M( D0D0 )M( D0 K+ ) M( D0K+ )

Sig

nal /

50

MeV

MC simulations of the Dalitz plot based on the determined strenghts of thequasi-two-body components: B+D0DsJ+(2700), B+(4160)K+ and B+(3770)K+

non-coherent approach (no interference)

maximal constructive interference

between DsJ(2700) and (4160)

maximal destructive interference


MC simulations for: fitted B Signal

Various decay models predictions versus data

None hypothesis can be rejected.

It is taken into account as source of systematic error, mainly on DsJ(2700) yield and parameters (see Table).

Interference between (4160) and (3770) is found to be negligible.

Acceptance corrected M(D0K+) spectrum

(Applied efficiency correction describes efficiency deviations along M(D0K+) from average efficiency it conserves total number of corrected events.)


M( D0 K+ )

Eff

. corr

ecte

d s

ign

al /

50 M

eV

for M(D0D0)>3.85 GeV

Acceptance-looses related systematic error on DsJ(2700) parameters


Systematic uncertainty on (4160):

no interference-effect related contribution (since (4160) is estimated from region without interference with DsJ(2700)) negligible systematics from acceptance looses range of fitting, fit parameterization and 3-body component yield gives N: ± 3%, M: ± 2MeV, : ± 5MeV

from DsJ(2700) and yields and parameters : NNR : +40% -27%

Systematic uncertainty on non-resonant component:


Angular distribution in the helicity frames of DsJ(2700), (4160) and (3770)

Background-free cos distribution obtained using 2-dim Mbc vs. E fit in each cos bin

DsJ(2700) region: 2.5<M(D0K+)<2.9 GeV

(4160) region: 3.95<M(D0D0)<4.25 GeV

(3770) region: M(D0D0)<3.85 GeV

Eff

. corr

ecte

d s

ign

al

Eff

. corr

ecte

d s

ign

al

Eff

. corr

ecte

d s

ign

al

DDcos DDcosDKcos

(4160) reflection

DsJ(2700) reflection

DsJ(2700) spin hypotheses:

J=1 2/n.d.f = 3.8/4J=2 2/n.d.f = 4.5/4J=0 2/n.d.f = 9.4/4

(4160) spin hypothesis: J=1 2/n.d.f = 1.3/3

(3770) spin hypothesis: J=1 2/n.d.f = 2.6/5

fitted B Signalcorrected for acceptance


Sig

nal

DDcosDKcos

Angular distributions in various decay models versus data

non-coherent approach (no interference)

maximal constructive interference


maximal destructive interference


MC simulations for:

fitted B signal not corrected for acceptance

The effect of maximal interferences is minor in angular distributions.

Estimation of contributions from other resonances


DsJ+(2573) spin-2 state

The M( D0 K+ ) Dalitz-plot projection is fitted

SELEX DsJ+(2632) state

N /

2 M

eV

M( D0 K+ )

M( D0 K+ )

N /

10M

eV

Fitted functions: BW(DsJ(2573))+BW(DsJ(2700))+Linear background with BW’s parameters fixed: M(DsJ(2573))=2573MeV (DsJ(2573))=15MeV M(DsJ(2700))=2713MeV (DsJ(2700))=130MeV

N(DsJ(2573))= 1.6 ± 4.4

Fitted functions: G(DsJ(2632))+Linear background with Gaussian parameters fixed: M(DsJ(2632))=2632MeV (DsJ(2632))=5MeV

N(DsJ(2632))= -2.3 ± 2.2


Branching fractions of components of BB++ D D00DD00KK++

BF( B+ D0DsJ+(2700) ) = (0.65 ± 0.10 +0.14 –0.15)10-3

BF( B+ (4160)K+ ) = (0.26 ± 0.05 ± 0.03)10-3

BF( B+ (3770)K+ ) = (0.19 ± 0.03 ± 0.03)10-3

BF( B+ D0D0K+ NR ) = (0.14 ± 0.05 +0.06 –0.04)10-3

90%C.L upper limits: BF( B+ D0DsJ+(2632) ) = 5.710-6

BF( B+ D0DsJ+(2573) ) = 1.610-4

BF( B+ Y(3940)K+ ) = 1.1 10-4

on quasi-two-body components of (for 250fb -1 ) (for 250fb -1 ) j.brodzicka, h.palka inp krakow dc...

Documents