jolanta brodzicka

JOLANTA BRODZICKA

Institute of Nuclear Physics, Krakow

ICPV MeetingDecember 12, 2002

Doubly charmed B decays

B D(*) D(*) K

JOLANTA BRODZICKA December 12, 2002

B D(*) D(*) K

Plan

b c c s transition “wrong-sign” D production physics motivations analysis details (very) preliminary results ( for ~78 fb-1 ) future plan


B D(*) D(*) K

Mechanisms of BD(*)D(*)K decays

( I ) through external W-emission amplitudes

( II ) internal W-emission amplitudes (color-suppressed)

( III ) external +internal W-emission amplitudes

phase-space suppressed b cW - c c s + dd (uu) pair creation

B+ D(*)0 D(*)+ K0

B0 D(*)- D(*)0 K+

B+ D(*)+ D(*)- K+

B0 D(*)0 D(*)0 K0

B0 D(*)- D(*)+ K0

B+ D(*)0 D(*)0 K+

22 decay modes + c.c


B D(*) D(*) K

Physics motivations charm counting puzzle

B D(*) D(*) K : significant (~1/2) contribution to b ccs transitions precise BF’s measurements needed

B0 D(*) D(*) K0S to probe both sin2 and cos2

small penguin pollution expected possible resonant contribution cc-bar states ((3770), (4040), …) upper-vertex D(*)K system vector-dominance model 1+ 1- particles easily produced from W-vertex (because of V-A) quasi-2-body B decays rather than 3-body

( e.g high BF`s for B D(*), a1 (1260) D(*), Ds*D )

expected decays to orbitally-excited Ds mesons followed by Ds** D(*)K

p-wave excited (c s) states : according to HQS 2 doublets :

jP = 1/2+ JP = (0 + , 1+ ) D*s0 D*s1 not seen, wide

jP = 3/2+ JP = (1 + , 2+ ) probably Ds1 ±(2536) DsJ ±(2573) narrow


B D(*) D(*) K

Analysis details at least 5 good tracks : abs(IP_dz)< 5cm abs(IP_dr)< 0.4cm R2< 0.3 K± : P(K/) > 0.6 ± : P(/K) > 0.6 electron veto: el_id < 0.95 K0

S abs( M(+ -) - MKs ) < 15 MeV only good_Ks

0 E > 50 MeV abs( M( ) -M0 ) < 15MeV

D±, D0 and D*±, D*0 reconstruction ( N(D)>1 : p(D) < 2 GeV )

B±, B0 reconstruction : all possible (22 + c.c) physical combinations D(*)D(*)K B vertex fit: with IP and B lifetime constraints “shape” cuts: abs(cosTHR)<0.8 abs(cosPROD)<0.8 Mbc > 5.2GeV -0.40 < E < 0.35 GeV


B D(*) D(*) K

D0

reconstruction

D0 K D0 K3 D0 K0

D0 Ks D0 KKD0 KsKK

S=93K S=22K S=101K

S=18K S=10K S=4K

D(*) plots for ~ 11fb-1 (exp17)

• vertex fit (refit 0 )

• M (DREC) cut: ± 20MeV

• (D0 K0 : ± 50MeV)

• constraint_mass fit

BF ~ 28%

for skimmed sample (with DDK candidate )

(doesn`t applied for these plots)


B D(*) D(*) K

D± reconstruction

D± K D± Ks

D± Ks0 D± KsK D± KK

BF ~ 15%

S=59K S=6.5K

S=1.7K S=10KS=4.4K

• reconstruction procedure like in D0 case

D(*) plots for ~ 11fb-1 (exp17)

D±


B D(*) D(*) K

D*± reconstructionD(*) plots for ~ 11fb-1 (exp17)

D*± D0 ± BF ~ 68%

• slow_ ID: P(/K) > 0.1• vertex fit

(constraints :IP, B)

• abs(M(D*)-M(D)-mPDG)< 2.5MeV

( D*± D± 0 hopeless )

D0 KD0 K3 D0 K0

D0 Ks

D0 KK D0 KsKK

S=6K

S=0.25KS=0.8KS=1.5K

S=9.5KS=9K


B D(*) D(*) K

D*0 reconstructionD(*) plots for ~ 11fb-1 (exp17)

• vertex fit

(constraints :IP, B) refit 0 (vtx_constraint)• abs(M(D*)-M(D)-mPDG)< 5MeV

D*0 D0 0

BF ~ 62%

D0 K D0 Ks D0 K0

S=0.4K S=3.5KS=1.5K


B D(*) D(*) K

Multi-candidates events treatment

more than 1 candidates in the same B sub-mode• multi D(*) candidates per event • D(*)D(*) combinations with different K`s

~3. B cand per event ( all sub-modes )

D, D* probabilities (LR):

B(B(MMDD**)) LR_DLR_D** ((MMDD**) =) =

S(S(MMDD**))

S(S(MMDD**))++

S(MD), B(MD)parameterization from MD fitB(MB(MDD))

LR_D (MLR_D (MDD) ) =S(MS(MDD))

S(MS(MDD))++

S(MD*), B( MD*) parameterization

from MD* fit


B D(*) D(*) K

Choice of the best B candidate

( for each B decay sub-mode separately )

LR_B = LR_DLR_B = LR_D(*) (*) ×× LR_D LR_D(*)(*)

• best B candidate : with max LR_B • equal LR_B case ( B`s differ only in K ) : larger K±_ID or better K0

S mass candidate chosen

B probability (LR_B)

S/(S+B) choice method “combines” both criteria:(M-MPDG)/ and S/B ratio


B D(*) D(*) K

LR_B cut efficiency LR_B cut: good for background reduction and s /b ratio

improvement

LR_D1 * LR_D2 cut LR_D1 * LR_D2 cut

Back

gro

und

reduct

ion (

DA

TA

)

Effi

cien

cy

reduct

ion (

sig

nal

MC

)

Signal MC: B± D0 D0B K± for all D0D0B combinations

Background: B± D0 D0B K± sideband

allall


B D(*) D(*) K

B± D0 D0B K± D0, D0 K

MASS_D0D0Bfor signal-box events

Mbc vs. E E

Mbc Mbc Mbc lost 2 lostS=16±4eff~11% S=87±10 S=157±12

comb. bckg

phase space

N/2

0M

eV


B D(*) D(*) K

B± D0 D0B K±

LR_Bcut

0.05

0.1

0.2

E MbcMbcMbc lost 2 lost

S=36±17 S=258±20 S=557±28

S=16±5 S=152±14 S=273±17

S=9±12 S=86±10 S=161±12


B D(*) D(*) K

B± D+ D- K±

E

lost

Mbc

Mbc

LR_B > 0.02

S=45±11

S=28±7


B D(*) D(*) K

B0 D0 D- K+

E

lost 2 lostMbc Mbc

Mbc

LR_B > 0.02

S=40±8

S=144±16

S=161±16


B D(*) D(*) K

B0 D0 D0B Ks (color suppressed channel )

E

lost 2 lost Mbc Mbc Mbc

LR_B > 0.01

S=3±3

S=62±10 S=104±14

JOLANTA BRODZICKA December 12, 2002B D(*) D(*) K

B0 D*± D0 K±

Mbc vs. E E

lost Mbc Mbc

LR_B > 0.005

S=137±12S=47±7


B0 D*± D0 Ks

Mbc vs. E E

lost Mbc Mbc

LR_B > 0.001

S=37±6

S=12±4


B0 D*0 D- K+

Mbc vs. E E

lost Mbc Mbc

LR_B > 0.002

S=48±10S=25±6


B D(*) D(*) K

B± D*0 D0 K±

MASS_D*K

for signal-box events

MASS_D*K

for lost -pion box events

E

lost Mbc Mbc

LR_B > 0.01

S=98±13

S=42±9

N/4

0M

eV

right flavor comb.

wrong flavor comb.

D*0K- D*0K+

D*0K+ D*0K-


B D(*) D(*) K

B0 D*±D*0 K±

E Mbc

LR_B > 0.0

S=18±5


B D(*) D(*) K

Future Plan

more D(*)D(*)K channels will be analyzed more attention for resonant structure exploration the stuff for 2-dim likelihood fits MC studies for background investigation BF’s determination incorporate D(*)D(*)K* channels


B D(*) D(*) K

LR_D*± vs. M plots

D0 K D0 K3

D0 K0D0 Ks

D0 KK D0 KsKK

LR_D0 vs. D_mass plots

jolanta brodzicka

Documents

event d

k0b0 d

k0b d

puzzle b d

uppervertex d

charmed b decaysb d

d expected decays

submodes d