1. Status of the experiments with the CMD-3 detector at VEPP-2000
FRASCATI
28 – 29 March, 2011

2. Short outline
1. Physical program in runs 2010 & Detector resolutions 3. Data taking 4. Some preliminary results 5. Nearest plans 2

3. Vector mesons in VEPP-2000 energy range
F. State
Mass, MeV
Width, MeV
Decay modes
13S1 (770)
775.490.34
149.10.8
Known to the level 105
13S1 (782)
0.12
8.49 0.08
13S1 (1020)
0.020
4.26 0.04
23S1 (1450)
146525
40060
, 4 seen
23S1 (1420)
1400  1450
180250
ρπ dominant
(1570)
157070
14490
May be an OZI-violating decay
mode of ρ(1700)
23S1 (1680)
168020
15050
K bar K* (892) + c.c. dominant
13D1 (1700)
172020
250100
2(+-) large,  dominant
13D1 (1650)
167030
31535
, ,  seen
13D1 (??)
??? (1900)
6 seen

4. Lay-out of VEPP-2000 SND beam length – 3.3 cm energy spread – 0.7 MeV
revolution time – 82 ns beam current – mA
beam length – cm energy spread – MeV
circumference – m beta function in IP x= z =4.3cm
L = 1032 cm-2s-1 at 2.0 GeV, L = 1031 cm-2s-1 at 1 GeV
CMD-3
SND

5. 3D view CMD-3 detector (real scale)
DC – 1218 hexagonal cells with sensitive
wires, W-Re alloy, 15  in diameter.
Z-chamber – start FLT, precise determine
z-coordinate ~ 500  (detector acceptance)
LXe calorimeter thickness 7 X0, 196 towers & 1286 strips. Spatial resolution 1 – 2 mm.
Calorimeter with CsI crystals (3.5t), 8 X0 8 octants, number of crystals
TOF – 16 counters, time resolution ~ 1ns
MR system – 8 octants, cosmic veto, ~ 1ns
Project magnetic field is 1.5 T
(we are working at 1T while)

6. First run: spring-summer 2010 Integrated luminosity, 1/nb
Beam energy, MeV
Date
Run numbers
Integrated luminosity, 1/nb
Events number, 10^6
Hard disk space, GB
OnLine
OffLine
700
# #6549
300 20
150
750
# #6693
400 17
145
800
# #6828
170 13
105
850
# #6937
340
15.5
100
900
# #7159
240 40
950
# #7340 75 25
1525
130.5
910

7. First run: spring-summer 2010
Collected integral luminosity 1.5 pb-1
Empty gaps reflect our problems with solenoid
reflect

8. First run: spring-summer 2010
event e+e-  e+e-
R-z plane
R- plane

9. First run: winter-spring 2010
Event e+e- ++

10. p-pbar event in SND (1900 MeV)10

11. Short run around  meson
15 – 30 December 2010
KK
Integr. lum .
 1.5 pb-1
KLKS

12. 2011 energy scan program from  to 2 GeV
2E, МeV
Integr. lum., nb-1
2E, MeV 1
1050
440 19
1975
5 days 2
1100
470 20
1925 3
1150
480 21
1875 4
1200
540 22
1825 5
1250
400 23
1775 6
1300 24
1725 7
1350
550 25
1675
500 8
1400
520 26
1625 9
1450
430 27
1575 10
1500 28
1525 11
1550
510 29
1475 12
1600 30
1425 13
1650
450 31
1375 14
1700 32
1325 15
1750 33
1275 16
1800 34
1225 17
1950 35
1175 18
2000
10 days 36
1125 37
1075
Up & down energy scan (shift on half step)
Integrated luminosity
20 pb-1 (equivalent to CMD-2 for all time)
Total program 180
days with current temp
Upper 1700 MeV –
max injection energy
Until summer ????

13. History data taking in 2011
Reason was found and eliminated. Vacuum degradation.
Spent 3 weeks to repair detector Up to now we haven’t pr.
Field quench

14. DC momentum resolutions
E= 505 MeV
E= 508 MeV
E= 510 MeV
E= MeV

15. DC & calorimeters resolutions
min=100 
e+ee+e
Ebeam=850 МeV
p/p=5%
m.i.p.
e+ee+e
CsI response vs energy deposition
in Lxe calorimeter
The summ energy deposition
In CsI & Lxe calorimetrs
e+ee+e
m.i.p.
E/E=6%

16. preliminary Preliminary results (2010): 2E>1.3 GeV p e+e  + K
Energy depos. vs momentum
electrons
muons K p
e+e   + a1+00
e+e  +
preliminary

17. One of the main physical task is to measure quantity R(s)
aμ(theory) = aμ(QED) + aμ(Weak) + aμ(Hadronic)
Contribution to am vs energy,
10 MeV step
Contribution to error of the am vs energy, 10 MeV step
black points- statistic
red points-systematic

18. What else? Depends on and value R(s)
About 40% of the error comes from energy range 1 to 2.5 GeV.
Today integrated luminosity inside this energy band is  200 nb-1.
After this energy scan we will have about 20 pb-1 (100 times more).

19. Nearest plans?
Collect integrated luminosity in this season about 20 pb-1.
Search for N-Ñbar, select events and study detection efficiency for this process (prepare preliminary results for summer conferences)
Study in detail 4, 5 and 6 channels
Vacuum chamber of the VEPP-2000 will be redone to increase dynamic aperture and arrange energy determination using Compton’s back scattering techniques (10-4). It can be taken about 3 – 4 months.
Low energy program will depend on success of the above item. But in any case short energy scan will be done. 19

20. Nearest plans?
RF system of the booster will be redone to provide beam energy injection up to 1000 MeV (850 MeV). We loose about 30% of integrated luminosity for higher energies while. The ramping up and ramping down of the beam energy in VEPP-2000 is a complicated arrangement and repeats in average every 15 minutes.
Luminosity is limited by positron storage rate (peak 1031). New injection complex will provide project luminosity 1032
The all elements for the new injection channel (length 100 m) are made and installed. Power supply equipment for lenses & magnets is in progress now. 80% is done.
During this time we will repair some detector imperfections. Some part of the digitizing electronics for LXe and ZC will be changed to a new one.

21. Conclusions VEPP-2000 started-up for data taking.
Idea with «round beams» proved luminosity enhancement.
Peak luminosity 1031 cm-2s-1 was achieved at phi – meson.
Potentially 2×1031 cm-2s-1 is possible at φ and 1.6×1032
cm-2s-1 at 2 GeV.
To reach the target luminosity, more positrons are needed.
Booster RF system upgrade is required. When will be done?
Beam en. calibr. is in progress now. All parts are available.
We plan to make low energy scan in the next run. Prelimi-
nary results will be reported on summer conferences. 21

22. Thank you
for your attention

23. Beam energy calibration23

24. DC resolutions R- (drift time) 100 140 m
R-z (charge division)  3 mm
(dE/dx) *dE/dx

25. Nearest plans? e  e+ VEPP-2000 BEP e+, e booster 850 MeV ILU CMD-3
Linac
B-3M
200 MeV
synchro-
betatron
BEP
e+, e
booster
850 MeV
SND
CMD-3
e  e+
convertor
2 m
VEPP-2000

26. Exclusive decay modes
Search for (1420) & (1650) decay into 3 vs energy
a1(1260) is enough to describe cross section dependence vs energy for 4 channel. But at high statistic  channel will contribute at notice- able level too? Search for intermediate dynamics is very importance.
5 channel with intermediate states (1450) & (1700) which can decay to 
6 channel - gold mode for search (1900). What is the mass? It is upper or lower of the threshold production N-Nbar? Is this state baryonium? Hybrid or something else?
Search for decay (1680)  K+K-, KSKL and strange vector hybrid
in decays (1680)  K*K  KK  &   K1(1400)K K*K  KK.
f0(980), , , radiation decays and physics of  и  mesons…

27. BaBar Radiation return Half statistic is processed (1450) (1570)
(1420)
(1650)
(1680)
(1700)
(1900)
Half statistic
is processed