viewofresultsfrom
SND
detector
August,30,2001
Review
ofresultsfrom
SND
detector
T.Dimova
BINP,Novosibirsk,Russia
D
BINP,Novosibirsk
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view of results from SND detector August,30,2001
VEPP-2M e+e� collider
,
Beam energy, MeV 180-700
Peak luminosity (Eb = 500MeV), cm�1s�1 3 � 1030
Energy spread (Eb = 500MeV), keV 300
Beam current, mA 50
Time between collisions, ns 60
Bunch length, cm 2
D BINP,Novosibirsk
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view of results from SND detector August,30,2001
SND Detector
3
4
5
1
26
10
9
7
13
12
8
11
0 20 40 60 80 100 cm
e e+-
2
3
1
6
8
7
9
11
1 - beam pipe, 2 - drift chambers, 3 - scintillation counter,4 - lightguides, 5 - PMTs, 6 - NaI(Tl)
crystals, 7 - vacuum phototriodes, 8 - iron absorber, 9 - streamer tubes, 10 - 1 cm iron plates, 11 -
scintillation counters, 12 and 13 - collider magnets.
D BINP,Novosibirsk
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viewofresultsfrom
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detector
August,30,2001
ListofSND
parameters:Calorimeter:
TotalnumberofNaI(Tl)counters
1632
Angularsizeofthecounter
�'=�#=9�
Energyresolutionfor 's
�E=E=
4:2%
4 p(E(GeV)
Angularresolutionfor 's
�'
=
0:82 �
pE
(G
eV
)�0:63�
Minimalspatialanglefor
twophotonsseparation
�'��#�18�
D
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view of results from SND detector August,30,2001
SND calorimeter performance
Invariant-mass spectra in �0 ! decay Invariant-mass spectra in K
S
! �
0�
0 decay
Mπγ, MeV
Even
ts
0
100
200
300
400
700 750 800 850
Invariant-mass spectra in ! ! �
0 decay
mπππ (MeV)
EV
EN
TS
EXP
- MC
0
100
200
300
400
450 500 550 600 650
Invariant-mass spectra in � ! 3�0 decay
D BINP,Novosibirsk
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viewofresultsfrom
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August,30,2001
ListofSND
parameters:Driftchambers:
��distributionfore+e�
!
�+��
��distributionfore+e�
!
�+��
Spatialresolutionfortracks
�'
=0:54�
,
(P=300MeV/c)
�#
=1:9�
Minimalazimuthangleforchargedparticlesseparation
�'�18�
Materialbeforethechamber
0.27g=cm2
Probabilityof -conversionbeforethechamber
0.57%
D
BINP,Novosibirsk
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viewofresultsfrom
SND
detector
August,30,2001
SND
trackingsystem
performance
dE=dxdistributionfor
e�and��
dE=dxdistributionfor
��andK�p
s�1GeV
�dE=dx�
30%
D
BINP,Novosibirsk
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view of results from SND detector August,30,2001
Integrated Luminosity
Experimental Years
IL(p
b)-1
per
Yea
r
0
5
10
15
20
2 4 6
Integrated luminosity collected by SND per
experimental year
√s-- (MeV)
IL (
pb
)-1
10-2
10-1
1
500 750 1000 1250
Integrated luminosity collected by SND in the energy
regionps = 360 { 1380 MeV
Total integrated luminosity IL ' 30 (pb)�1 (1995 { 2000 )
Luminosity measurement:
e+e� ! e+e�, e+e� !
Accuracy � 1.5% { 2%
D BINP,Novosibirsk
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view of results from SND detector August,30,2001
Electric dipole radiative decays
V S γ
l=0,s=1 l=1,s=1V ! S
(V = �; !; �)
(S = f0(980); a0(980); �(?))
SND study:
e+e� ! �! �0�0 , ��0
e+e� ! ! ! �0�0 ,
e+e� ! �! �0�0
D BINP,Novosibirsk
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view of results from SND detector August,30,2001
Electric dipole radiative decays of � meson
m ππ , MeV
dB(
φπ0 π
0 γ)/d
mπ
π10
8 MeV
-1
f 0γ + ρ0π
0
0
20
40
60
80
400 600 800 1000
x
xmηπ , MeV
dΒ(φ
ηπγ)/
dm10
7 MeV
-1
0
5
10
15
700 800 900 1000
B(�! �0�0 ) = (1:22� 0:12) � 10�4
B(�! ��0 ) = (0:88� 0:17) � 10�4
B(�! f0 ) = (3:5� 0:3�1:30:5) � 10�4
B(�! a0 ) = (0:88� 0:17) � 10�4
D BINP,Novosibirsk
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viewofresultsfrom
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August,30,2001
Electricdipoleradiativedecaysof�
meson
SND
CMD-2
KLOE(�
)
B(�!�0�0 )(�10�
4)
1:034�0:066�0:046
0:92�0:08�0:06
0:79�0:02�0:08
m��
>700MeV
B(�!��0 )
0:88�0:17
0:90�0:24�0:10
0:74�0:05�0:07
(�10�
4)
B(�!f0 )
3:5�0:3+1:3
�
0:5
2:90�0:21�1:54
2:37�0:06�0:24
(�10�
4)
B(�!a0 )
0:88�0:17
0:58�0:05�0:06
(�10�
4)
(*)-systematicerrorwassetto10%
D
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view of results from SND detector August,30,2001
�, ! ! �0�0 decays
E, MeV
Cro
ss s
ecti
on, n
b
0
0.1
0.2
0.3
0.4
0.5
0.6
600 650 700 750 800 850 900 950
e+e� ! �
0�
0 cross-section
SND results (IL = 9 (pb)�1):
B(! ! �0�0 ) = (6:3� 1:4� 0:8) � 10�5
B(�! �0�0 ) = (4:0�1:00:9 �0:4) � 10�5
B(�! S ! �0�0 ) = (2:0�0:80:7 �0:3) � 10�5
D BINP,Novosibirsk
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Magnetic dipole radiative decays
V P γ
l=0,s=1 l=0,s=0V ! P
(V = �; !; �)
(P = �0; �; �0)
SND study:
e+e� ! �! �0 , �0 , � ,
e+e� ! ! ! �0 , �
e+e� ! �! �0 , �
D BINP,Novosibirsk
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view of results from SND detector August,30,2001
�! �0
EntriesMeanRMS
17 937.8 33.70
0
0.5
1
1.5
2
2.5
3
860 880 900 920 940 960 980
�0
! �+��
�; � ! :
B(�! �0
) = (6:7�3:4
2:9) � 10�5
�0
! �0�0�; � ! :
B(�! �0
) = (4:3� 1:6� 0:9) � 10�5
SND CMD2 KLOE
B(�! �0 ) � 105 4:9�1:61:5 6:4� 1:6 6:8� 0:8
D BINP,Novosibirsk
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�; !; �! �
2E 0, MeV
σ, n
b
0
0.5
1
1.5
2
2.5
3
3.5
4
700 720 740 760 780 800 820 840
2E 0, MeV
0
10
20
30
40
50
60
1000 1005 1010 1015 1020 1025 1030 1035 1040
B(�! � )(�10�2)
� ! : 1:34� 0:01� 0:05
� ! �+��
�0:1:26� 0:03� 0:06
� ! �0�0�0:1:35� 0:01� 0:05
Average: 1:310� 0:045
B(�! � ) = (2:77� 0:26� 0:16) � 10�4
B(! ! � ) = (4:22� 0:47� 0:17) � 10�4
Experimental ratio of the partial width:
�!� : ��� : ��� = 1 : (11:7� 1:9) : (15:9� 1:9)
Prediction of the simple quark model: 1:8:12
D BINP,Novosibirsk
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view of results from SND detector August,30,2001
�; !; �! �0
√s-, MeV
σ, n
b
1
10
10 2
600 700 800 900 1000B(�! �0 ) = (5:03� 1:17� 0:83) � 10�4
B(! ! �0 ) = (9:17� 0:16� 0:46) � 10�2
B(�! �0 ) = (1:23� 0:04� 0:09) � 10�3
Experimental ratio of the partial width:
�!�0 : ���0 : ���0 = 1 : (0:97� 2:8) : (7� 0:6) � 10�3
Prediction of the quark model: 1 : 1/9 : 0.01
D BINP,Novosibirsk
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view of results from SND detector August,30,2001
Conversion decays �! �e+e�; �! �0e+e�; � ! e+e�
*-
+e
e
γ
(γ)PV(P)
F(q )2
Branching Ratios
�! �e+e�
� ! e+e� �! �0e+e�
(�10�4) (�10�3) (�10�5)
SND 1:19� 0:22 5:15� 0:96 1:05� 0:37
CMD-2 1:17� 0:12 7:10� 0:79 1:22� 0:40
SND&CMD-2 1:18� 0:11 6:31� 0:61 1:13� 0:27
Theory 1:10� 0:1 6.5{6.8 1.3{1.6
PDG(2000) 1:3+0:8�0:6 4:9� 1:1 < 1:2 � 10�4
q2
dq2
+-
dB(V
Pee
)
32
1
e2(2m )
Transition Form Factors Slopes
�! �e+e�
� ! e+e� �! �0e+e�
GeV�2 GeV�2 GeV�2
SND 3:8� 1:8 1:6� 2:0 |
Theory (VDM) 1.0 1.8
Previous
measurement | �0:7� 1:5 |
D BINP,Novosibirsk
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view of results from SND detector August,30,2001
OZI and G-parity suppressed �! !�0 and �+�� decays
E, MeV
σvi
s,n
b
0
5
10
15
20
25
980 1000 1020 1040 1060
e+
e�
! �+
��
E, MeVV
isib
le c
ro
ss s
ecti
on
, n
b
0
0.2
0.4
0.6
0.8
1
1.2
1.4
980 1000 1020 1040 1060
e+
e�
! !�0
�(s) = �0(s)�
��
��
��1� Z
m���
D�(s)�
��
��
�2
�+
��
!�0
Re(Z) 0:061� 0:006 0:108� 0:16
Im(Z) �0:041� 0:007 �0:125� 0:020
B(�! X) � 105 7:1� 1:4 5:2�1:3
1:1
D BINP,Novosibirsk
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viewofresultsfrom
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August,30,2001
�m
eson
param
etersstudy
e+
e�
!�+
��
�0,
K
+
K
�
,
K
S
K
L
980
�ps
�1060
MeV
IL
=
8:5
(pb)�
1
N
K
+
K
�
=
106
N
K
S
K
L
=
0:5
�106
N
3�
=
0:4
�106
D
BINP,Novosibirsk
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viewofresultsfrom
SND
detector
August,30,2001
�
mesonparametersstudy
SND
PDG-2000
m
�
,MeV
1019:42�0:05
1019:417�0:014
��
,MeV
4:21�0:04
4:458�0:032
B
(�
!e+e�
)�104
2:93�0:14
2:91�0:07
B
(�
!K
+K
�
),%
47:6�1:7
49:2�0:7
B
(�
!K
S
K
L
),%
35:1�1:3
33:8�0:6
B
(�
!3�),%
15:9�0:8
15:5�0:6
B
(�
!� ),%
1:33�0:06
1:297�0:033
g�
K
+
K
�
g�
K
S
K
L
1
pZ
(m
�
)
0:92�0:03
0:95�0:01
D
BINP,Novosibirsk
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viewofresultsfrom
SND
detector
August,30,2001
�
mesonparametersstudy
4 5
CMD2-01
SND-00
CMD2-98
CMD2-95
SPEC-86
AEMS-82
OLYA-81
WIRE-80
OLYA-78
CNTR-74
OSPK-71
OSPK-70
Γφ(MeV)
D
BINP,Novosibirsk
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viewofresultsfrom
SND
detector
August,30,2001
e+e�annihilationintohadronsabove1GeV
SND
studiesofthee+e �!
hadrons:
�
e+e �!
��;!�!
�+���0
�
e+e �!
!�!
�0�0
�
e+e �!
���!
�+���+��
�
e+e �!
!�;���;�+��!
�+���0�0
�
e+e �!
!��;���!
�+���+���0
�
e+e �!
K
SK
L
D
BINP,Novosibirsk
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view of results from SND detector August,30,2001
e+e�! �0�0
SNDDM2CMD2CLEO
E, MeV
Cro
ss s
ecti
on, n
b
0
0.5
1
1.5
1000 1200 1400 1600 1800 2000 2200
e+e� ! !� ! �0�0
Systematic error: 5 %
D BINP,Novosibirsk
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view of results from SND detector August,30,2001
e+e�! �+���0�0
√s-- (MeV)
σ (n
b) SND
SND, ωπo→ πoπoγ CLEO, τ→ ωπoντ CMD2 DM2
0
5
10
15
20
25
1000 1250 1500 1750 2000
√s-- (MeV)
σ (n
b)
SND CLEO, τ→ 3ππoντ CMD2 DM2
0
5
10
15
20
25
1000 1250 1500 1750 2000
e+
e� ! !�0
Systematic error: 20 % (ps < 1150 MeV)
15 % (ps > 1150 MeV)
e+
e� ! �+
��2�0
(!�0
subtracted)
Systematic error: 20 %
D BINP,Novosibirsk
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view of results from SND detector August,30,2001
e+e�! �+���+��
√s-- (MeV)
σ (n
b)
SND CLEO, τ→ 3ππoντ CMD2 DM2
0
10
20
30
40
1000 1250 1500 1750 2000
√s-- (MeV)
σ 2π+
2π- /
σπ+
π- 2πo
1
2
3
1100 1200 1300 1400
e+
e� ! �+
��
�+
��
Systematic error: 12 % (ps < 1150 MeV)
8 % (ps > 1150 MeV)
��+���+��
=��+���0�0
D BINP,Novosibirsk
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view of results from SND detector August,30,2001
e+e�! �+���+���0
√s-- (MeV)
σ (n
b)
SND CMD2 DM2
0
0.2
0.4
0.6
0.8
1
1200 1300 1400 1500
√s-- (MeV)
σ (n
b)
SND
CMD2
DM2
0
1
2
3
4
5
1200 1300 1400 1500
e+e� ! !�+��
e+e� ! ��+��
D BINP,Novosibirsk
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view of results from SND detector August,30,2001
e+e�! KSKL2E0, MeV
σ 0(e+
e- →K
SKL),
nb
SND VEPP2M'97-99 OLYA VEPP2M'82 DM1 DCI'80
10-2
10-1
1
10
10 2
10 3
1000 1200 1400 1600 1800 2000 2200
e+e� ! KSKL
(KS ! �0�0)
Systematic error: 7 % (p
s < 1100) MeV, 16 % (p
s > 1100) MeV
D BINP,Novosibirsk
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view of results from SND detector August,30,2001
e+e�! �+���0
2Eo, MeV
σ 3π, n
b
SND-2001
SND-1999
DM2-1992
0
1
2
3
4
5
6
7
8
1200 1400 1600 1800 2000
Systematic error: 5 %
D BINP,Novosibirsk
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view of results from SND detector August,30,2001
e+e�! �+���0 + !�+��
√s-- (MeV)
σ (n
b)
SND DM2
0
2
4
6
8
1000 1250 1500 1750 2000
e+
e�
! �
+
�
�
�
0 √s-- (MeV)
σ (n
b)
SND
DM2
0
1
2
3
4
1250 1500 1750 2000
e+
e�
! !�
+
�
�
!1
!2
!3
m, MeV 1250�29 1400�19 1771�28
�, MeV 426�135 626�89 473�76
�(V ! ��), nb 0.56�0.25 3.90�0.39 2.28�0.46
�(V ! !��), nb 0 0.046�0.039 2.49�0.33
� � � 0
�(V ! e+
e�),eV � 25 � 300 � 470
D BINP,Novosibirsk
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viewofresultsfrom
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August,30,2001
New
project:VEPP-2000
Maximum
beam
energy{1GeV
Perimeter{24.388m
Timebetweencollisions{0.04�s
parametersatEbeam
=900MeV:
Luminosity{1�1032
Beam
current{200mA
Numberofparticlesinonebunch{1�1011
Bunchlength{3.3cm
Betafunctionatinteractionpoint{�x
=�z=6:3cm
Energyspread{�E
=6:4�10�
4
D
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view of results from SND detector August,30,2001
New project: SND Upgrade
3
2
1
µ−
µ+
4
6
5
7
9
3
1
2
4
8
7
5
10
6
9
0 20 40 60 80 100 cm
µ −
µ +
e e+-
1 - beam pipe, 2 - drift chamber, 3 - aerogel cherenkov counters, 4 - NaI(Tl) crystals, 5 - vacuum
phototriodes, 6 - iron absorber, 7 - streamer tubes, 8 - 1cm iron absorber, 9 - scintillation
counters, 10 - solenoids
D BINP,Novosibirsk
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viewofresultsfrom
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August,30,2001
New
project:SND
Upgrade
Driftchamber
�R�
�
=150�m;�z=1�1:5mm;
��
=��=0:25�
(jet,gasAr+10%CO2)
dE/dx:�=K
forjpj�300MeV;
=0:94�4�
Calorimeter
newphototriodsandelectronics
AerogelCounters
�=K
for250MeV<jpj<900MeV
Physicsprogram
�measurementofcrosssectionsofdi�erentprocesses,forexample,
e+e�
!2�;��;!�;KK;4�;KK�etc.;
�measurementoffullcrosssectione+e�
!hadrons;
�studyingofparametersofvectorresonancesinenergyrange1:2�2GeV;
�n�n,p�pform
factorsonthreshold;
�two-photonphysics:e+e�
!e+e�
+�0;�;�0;2�0
etc.
D
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