Transcript Prezentacja programu PowerPoint

New Resonance in D0K+
Jolanta Brodzicka, Henryk Palka
INP Krakow
BGM
August 10, 2004

for 250fb-1
(exp7-37)
B+ D0D0K+
 B0 D-D0K+
Outline :
 B+ D0D0K+ B0 D-D0K+ for 250fb-1
 Dalitz plots and projections
 Background-free M(D0K+) distributions
 Fits to M(D0K+) and the DsJ(2720) parameters
 Angular distrbutions
 Conclusions
N/7.5MeV
B+  D0D0K+
LR > 0.04
for Mbc >5.273 GeV
Fitting method:
2-dim Mbc vs. E unbinned likelihood fit:
L_Sig(Mbc, E) = S•( G (Mbc) • G (E) )
+ S•( G (Mbc) • G (E) )
+ S2•( G (Mbc) • G (E) )2
L_Bckg (Mbc, E) = B•ARG (Mbc) • POL_2 (E)
L= L_Sig + L_Bckg
S , S2 : regions with missing ,2
N/2.5MeV
E
for E<18MeV
Fit result:
S = 145.2 ± 17.3
S/B=0.55
G0(E) = -0.27E-02 ± 0.07E-02
GeV
 (E) = 0.50E-02 ± 0.06E-02 GeV
G0(Mbc) = 5.2814 ± 0.0003 GeV
 (Mbc) = 0.24E-02 ± 0.02E-02 GeV
Mbc
Jolanta Brodzicka, Henryk Palka INP Krakow
ICPV
August 10, 2004
N/7.5MeV
B0  D-D0K+
LR > 0.01
for Mbc >5.273 GeV
Fit result (for fully reconstructed region):
S = 191.3 ± 19.2
N/2.5MeV
E
for E<18MeV
Mbc
Jolanta Brodzicka, Henryk Palka INP Krakow
S/B=0.46
G0(E) = -0.17E-02 ± 0.07E-02 GeV
 (E) =
0.57E-02 ± 0.06E-02 GeV
G0(Mbc) = 5.2808 ± 0.0003 GeV
 (Mbc) = 0.25E-02 ± 0.02E-02 GeV
ICPV
August 10, 2004
Mode
Signal
for 140fb-1
eff [ 10-4 ]
BF [ 10-3 ]
Signal
for 250fb-1
B+  D0D0K+
94.4 ± 13.0
4.80 ± 0.14
1.30 ± 0.18 ± 0.21
145.2 ± 17.3
B0  D-D0K+
127.6 ± 15.3
6.98 ± 0.14
1.68 ± 0.20 ± 0.25
191.3 ± 19.2
BF calculations based on 140fb-1
Jolanta Brodzicka, Henryk Palka INP Krakow
ICPV
August 10, 2004
Dalitz plot and projections for
for signal-box events :
Mbc > 5.273 GeV E<16 MeV (~3 )
M2(
D
Background: elliptical strip
in
K+ )
0
N / 20MeV
DsJ(2573) DsJ(2720)
M2( D0D0 )
B+  D0D0K+
LR > 0.04
6 to 10
Mbc, E, surrounding the signal region
(4160)
(3770)
(4040)
DsJ(2720)
reflection
(4160)
(3770)
M( D0D0 )
(3770) reflection
DsJ(2573)
N / 20MeV
N / 20MeV
DsJ(2720) (4160) reflection possible
(3770) reflection
M( D0K+ )
M( D0 K+ )
Jolanta Brodzicka, Henryk Palka INP Krakow
(4160) reflection
ICPV
August 10, 2004
Dalitz plot and projections
B0  D-D0K+
Mbc > 5.273 GeV E<18 MeV (~3 )
for signal-box events :
N / 20MeV
M2( D0D- )
reflection
M( D-D0 )
M2( D0K+ )
DsJ(2720)
M( D0K+ )
Jolanta Brodzicka, Henryk Palka INP Krakow
DsJ(2720)
N / 20MeV
N / 20MeV
Background normalized to
number of bckgd. events in
signal box
DsJ(2573) DsJ(2720)
DsJ(2573)
LR > 0.01
ICPV
M( D-K+ )
August 10, 2004
M(D0K+) background subtracted distributions
B signal in M( D0K+ ) bins
2dim Mbc vs. E fits in M( D0K+ ) bins
B+  D0D0K+
Signal / 50MeV
Signal / 50MeV
•peak at 2.720 GeV seen, no DsJ(2573)
• (3770) reflections at 3.1 and 3.3GeV
• is the (4160) contributing to 2720 peak?
B0  D-D0K+
•DsJ(2720) observed and a shoulder (DsJ(2573) ?)
M( D0K+ )
fitted Signal with error
Jolanta Brodzicka, Henryk Palka INP Krakow
ICPV
August 10, 2004
Signal / 50MeV
M(D0D0) background subtracted distribution for
(3770)
(4160)
B+  D0D0K+
M( D0K+ ) peak at 2.7GeV
contributed to the (4160) and vice versa
(they overlap on Dalitz plot)
To estimate of the (4160) contribution
to the 2.7GeV peak:
M(D0D0) for M(D0K+) > 2.9GeV
( ≡ ½ of the (4160) helicity distr.)
(4160) contribution to the DsJ(2720)
11± 5 events
Reflection shape: (according to cos2 angular
distribution of the polarized (4160) )
From MC : B+ (4160) K+
Signal / 50MeV
M(D0 D0)
(4160)
M(D0 D0)
Jolanta Brodzicka, Henryk Palka INP Krakow
ICPV
August 10, 2004
Fits to background-free D0K+ mass spectra (1)
• resonances described by non-relativistic Breit-Wigners
• Phase Space (nonresonant component) is described by 3body MC PS
• Reflection shape: (according to cos2 angular distribution of the polarized (4160) )
from MC : B+ (4160) K+

fitted B Signal
D0D0K+
Signal / 50MeV
B+
DsJ(2720)
N = 70.8 ± 11.6
M = 2706 ± 13 MeV
 = 139 ± 34 MeV
M( D0K+ )
reflection from (4160) (+ non-resonant component )
(3770) region removed: M(D0D0)>3845
Jolanta Brodzicka, Henryk Palka INP Krakow
ICPV
August 10, 2004
Fits to background-free D0K+ mass spectra (2)
• resonances described by non-relativistic Breit-Wigners
• DsJ(2573) the convolution BW  G(=50MeV)
• Phase Space (nonresonant component) is described by 3body MC PS
fitted B Signal
Signal / 50MeV
B0  D-D0K+
Fit
variants:
M( D0K+ )
DsJ(2573)
N = 10.8 ± 3.6
M = 2573 MeV fixed
 = 15 MeV fixed
DsJ(2720)
N = 126.7 ± 15.1
M = 2706 MeV fixed
 = 139 MeV fixed
Jolanta Brodzicka, Henryk Palka INP Krakow
Yield
M MeV
 MeV
2/ndf
127 ±15
2700 ± 8
139
fixed
14.7/13
133 ±20
2706
fixed
154 ±33
14.3/13
138 ±19
2695 ±11
166 ±31
15.4/13
ICPV
August 10, 2004
Angular distribution (2)
DsJ (2720) region:
B
DD0K+
Acceptance for signal MC
B+  D0 DsJ(2720) (K)(K)
For DsJ(2720) J=2 assumed
Ang.distribution:
9cos4  -6cos2  +1
(previously 3-body D0D0K+ MC )
signal-box
Eff. corrected signal
2.64 < M(D0K+) < 2.8 GeV (80MeV window )
B+  D0D0K+
J=1 hypothesis
/n.d.f = 16/4
J=2 hypothesis
/n.d.f = 40/4
Eff. corrected signal
cos
cos
B0  D-D0K+
cos
Acceptance for signal MC
B0  D- DsJ(2720) (K)(K)
For DsJ(2720) J=2 assumed
(previously 3-body D-D0K+ MC )
J=1 hypothesis
/n.d.f = 12/4
J=2 hypothesis
/n.d.f = 20/4
fitted B Signal corrected for acceptance
Jolanta Brodzicka, Henryk Palka INP Krakow
ICPV
August 10, 2004
cos
Angular distribution
K+
Helicity angle  :
K+

D0K+
angle between
momentum in
rest frame
and D0K+ momentum (the boost direction) in B rest frame
D0K+
cos distribution obtained using
2-dim Mbc vs. E fit in each cos bin (to subtract background)
D (2573) region: B0  D-D0K+ signal-box
SJ
Eff. corrected signal
2.54 < M(D0K+) < 2.6 GeV
(30 MeV window )
B
D
D0
Acceptance for MC:
B0  D- DsJ(2573) (K)(K)
For DsJ(2573) J=2
Ang.distribution: 9cos4  - 6cos2  + 1
(previously 3-body D-D0K+ MC used)
Compatible with
J=2
cos
fitted B Signal corrected for acceptance
Jolanta Brodzicka, Henryk Palka INP Krakow
cos
ICPV
August 10, 2004
Conclusions
 In 250fb-1 clean (S/B=0.5) DDK samples observed :
145 ± 17
B+ D0D0K+ (external+colour suppressed)
191 ± 19 B0  D-D0K+ (external)
BF (D-D0K+) /BF (D0D0K+ ) = 1.1 ± 0.2 ± 0.2
 Background-free 2-body mass spectra obtained and analysed
M(D0K+) dominated by the resonant structure at 2720
(~50% in B+ D0D0K+ , ~70% in B0  D-D0K+ )
(3770), (4160) charmonia (~50% in B+ D0D0K+ )
Nonresonant contribution is negligible
 DsJ(2720) → D0K+ observed in both reactions:
In B+ D0D0K+ : N = 70.8 ± 11.6
M = 2706 ± 13 MeV
 = 139 ± 34 MeV
In B0  D-D0K+ : N = 126.7 ± 15.1
M = 2706 MeV fixed
 = 139 MeV fixed
Spin cannot be decided but J=1 prefered
Many predicted states in this region (radial qq, chiral doublers etc.)
DsJ(2573) needed to describe D0K+ mass spectrum in B0  D-D0K+
Jolanta Brodzicka, Henryk Palka INP Krakow
ICPV
August 10, 2004
Backup slides
Jolanta Brodzicka, Henryk Palka INP Krakow
ICPV
August 10, 2004
Mbc & E “movie”
for B0 D0D0K+
from 2dim Mbc vs. E
fit
in M( D0K+ ) 50MeV bins
M( D0K+ ) bin
2.65 - 2.70 GeV
2.45 - 2.50 GeV
2.50 - 2.55 GeV
2.70 - 2.75 GeV
2.55 - 2.60 GeV
2.75 - 2.80 GeV
2.60 - 2.65 GeV
2.85 - 2.90 GeV
Mbc
E
Jolanta Brodzicka, Henryk Palka INP Krakow
ICPV
Mbc
August 10, 2004
E
Mbc & E “movie”
for B0 D-D0K+
from 2dim Mbc vs. E
fit
in M( D0K+ ) 50MeV bins
M( D0K+ ) bin
2.65 - 2.70 GeV
2.45 - 2.50 GeV
2.50 - 2.55 GeV
2.70 - 2.75 GeV
2.55 - 2.60 GeV
2.75 - 2.80 GeV
2.60 - 2.65 GeV
2.85 - 2.90 GeV
Mbc
E
Jolanta Brodzicka, Henryk Palka INP Krakow
ICPV
Mbc
August 10, 2004
E
B0  D*-D0K+
Dalitz plot and projections
Mbc > 5.273 GeV E<30 MeV (~3 )
Background
M2 ( D0K+ )
N / 20MeV
for signal-box events :
LR > 0.005
DsJ(2720)
DsJ(2573)
DsJ(2720)
M( D0K+ )
Jolanta Brodzicka, Henryk Palka INP Krakow
M( D*-D0 )
N / 20MeV
N / 20MeV
M2 ( D0D*- )
ICPV
M( D*-K+ )
August 10, 2004
N/7.5MeV
B0  D*-D0K+
Fit result (for fully reconstr. region):
LR > 0.005
S/B=0.82
S = 222.4 ± 21.5
G0(E) = -0.36E-02 ± 0.09E-02 GeV
for Mbc >5.273 GeV
 (E) =
0.99E-02 ± 0.10E-02 GeV
G0(Mbc) = 5.2814 ± 0.0003 GeV
 (Mbc) = 0.26E-02 ± 0.02E-02 GeV
E
for E<30MeV
fitted B Signal
in M(D0K+) bins
Signal / 50MeV
N/2.5MeV
B0  D*-D0K+
DsJ(2573)
Mbc
Jolanta Brodzicka, Henryk Palka INP Krakow
M( D0K+ )
N = 29.9 ± 7.5
M = 2573 MeV fixed
 = 15 MeV fixed
ICPV
DsJ(2720)
N = 145.8 ± 21.9
M = 2706 MeV fixed
 = 139 MeV fixed
August 10, 2004
D0K+ from continuum
 for 230 fb-1
DsJ(2573)
DsJ(2720)
N/20MeV
N/20MeV
M(D)-M(DPDG)  < 20MeV
 D0  K
 DK vertex fit with IP constraint (to reduce background) cl>.9
 P*(DK) > 3.5 GeV in (4S) system
 for 260 * 106 cc continuum MC
M( D0K+ )
Jolanta Brodzicka, Henryk Palka INP Krakow
M( D0K+ )
ICPV
August 10, 2004
Signal / 50MeV
B+  D0D0K+
M( D0K+ ) – M(D0K+)
„right” - ”wrong” flavour combinations
to remove reflections from charmonium states
DsJ(2720)
N = 65.1 ± 8.4
M = 2710 ± 7 MeV
 = 112 ± 22 MeV
Jolanta Brodzicka, Henryk Palka INP Krakow
ICPV
August 10, 2004
Background subtracted mass distributions
B+  D0D0K+
Signal / 50MeV
Signal / 50MeV
wrong flavour comb.
M( D0D0 )
Jolanta Brodzicka, Henryk Palka INP Krakow
M( D0K+ )
ICPV
August 10, 2004
Angular distribution uncorrected for acceptance
DSJ (2573) region:
2.54 <
M(D0K+)
B0  D-D0K+ signal-box
fitted B Signal
< 2.6 GeV
B0  D-D0K+
cos
DsJ (2720) region:
B  DD0K+ signal-box
2.64 < M(D0K+) < 2.8 GeV
B0  D-D0K+
cos
Jolanta Brodzicka, Henryk Palka INP Krakow
B+  D0D0K+
ICPV
cos
August 10, 2004
Angular distribution : fits with J hypothesis of DsJ(2720)
DsJ (2720) region:
2.64 <
M(D0K+)
B  D0D0K+ signal-box
fitted B Signal
< 2.8 GeV
J=1 hypothesis
J=2 hypothesis
cos2
/n.d.f = 16/4
9cos4-6cos2+1
/n.d.f = 40/4
cos
DsJ (2720) region:
cos
B  D-D0K+ signal-box
2.64 < M(D0K+) < 2.8 GeV
J=2 hypothesis
J=1 hypothesis
9cos4-6cos2+1
/n.d.f = 20/4
cos2
/n.d.f = 12/4
cos
Jolanta Brodzicka, Henryk Palka INP Krakow
cos
ICPV
August 10, 2004
Analysis method
 selection cuts
accepted events : R2< 0.3
tracks : IP_dz< 5cm IP_dr< 0.4cm
K± :
K 0S :
0
P(K/) > 0.4
± : P(/K) > 0.1
electron veto: el_id < 0.95
M(+ -) - MKs <15MeV
only good K0s accepted
: E >50 MeV M( ) -M0 <15MeV
 D(*) reconstruction
D0  K, K3, K0, Ks, KK
D±  K, Ks, KK, KsK
BF ~ 28% of total
BF ~ 12% of total
M(D)-M(DPDG)  < 20MeV ( D0 K0 : -50MeV )
vertex fit (cl > 0.) and mass constraint fit applied
p(D) < 2 GeV in (4S) system
D(*) ±  D0 ±
M(D*)-M(D)-mPDG)  < 2.5MeV
vertex fit (cl > 0.)
 B D(*)D(*)K reconstruction
B vertex fit: with IP and B constraints
Mbc > 5.2 GeV
-0.40 < E < 0.35 GeV
Jolanta Brodzicka, Henryk Palka INP Krakow
ICPV
August 10, 2004
D plots for ~11fb-1 after preselection
p(D) < 2GeV in (4S) system
Multi-candidates events treatment
D0  K
D0 K3
D probabilities ( LR_D ):
LR_D
LR_D ( MD )=
S(MD)
LR_D
S(MD) + B(MD)
S(MD), B(MD) parameterization from
fits to data ( inclusively reconstructed
D0, D± in each decay mode separately )
MD
MD
D0 K0
LR_D
B probability ( LR_B ):
LR_B = LR_D1
×
LR_D2
 best B candidate :
with max LR_B
D±  K
MD
D± Ks
LR_D
LR_D
LR_B used also for
background
discrimination
MD
Jolanta Brodzicka, Henryk Palka INP Krakow
ICPV
August 10, 2004
MD
LR_B cut
Data
( good for background reduction
and S/B improvement )
B+  D0D0K+
for Mbc>5.27GeV
no LR_B cut
S / sqrt (S + B )
Signal MC B+  D0D0K+
LR_B > 0.04
LR_B > 0.1
LR_D0 * LR_D0 cut
Signal MC
B+  D0D0K+
BF = 1.5 * 10-3
Background: B+  D0D0K+ Mbc sideband
E
Jolanta Brodzicka, Henryk Palka INP Krakow
ICPV
August 10, 2004
Physics motivations
B  D(*)D(*)K : good place to explore spectroscopy:
b  cW - c c s + dd (uu)
D(*) K from W vertex
Leading quark diagrams:
B+  D0D0K+
B0  D-D0K+
B0  D*-D0K+
 only External diagram
 D0K+ is the only non-exotic comb.,
 External + Internal diagrams
 Both
_ DK and DD states expected
 D0K+ is exotic
Jolanta Brodzicka, Henryk Palka INP Krakow
D*-D0 have > 2q content
ICPV
August 10, 2004
Jolanta Brodzicka, Henryk Palka INP Krakow
ICPV
August 10, 2004