Status of the experiments with the CMD-3 detector at VEPP-2000 FRASCATI 28 – 29 March, 2011
Short outline • 1. Physical program in runs 2010 & 20112. Detector resolutions3. Data taking4. Some preliminary results5. Nearest plans
CMD-3 Lay-out of VEPP-2000 • revolution time – 82 ns beam current– 200 mA • beam length – 3.3 cm energy spread– 0.7 MeV • circumference– 24.4 m beta function in IP x=z =4.3cm • L = 1032cm-2s-1at 2.0 GeV, L = 1031cm-2s-1 at 1 GeV SND
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 - 1152. 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)
First run: spring-summer 2010 Collected integral luminosity 1.5 pb-1 Empty gaps reflect our problems with solenoid reflect
First run: spring-summer 2010 event e+e- e+e- R-z plane R- plane
First run: winter-spring 2010 Event e+e-++
Short run around meson 15 – 30 December 2010 KK Integr. lum . 1.5 pb-1 KLKS
2011 energy scan program from to 2 GeV • Up & down energy scan (shift on half step) • Integratedluminosity • 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 ????
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
DC momentum resolutions E= 505 MeV E= 508 MeV E= 511.5 MeV E= 510 MeV
DC & calorimeters resolutions m.i.p. e+ee+e min=100 e+ee+e Ebeam=850 МeV p/p=5% CsIresponse vs energy deposition in Lxe calorimeter The summ energydeposition In CsI &Lxe calorimetrs e+ee+e m.i.p. E/E=6%
Preliminary results (2010): 2E>1.3 GeV Energy depos. vs momentum electrons p K muons e+e + a1+00 e+e+ preliminary
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
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 about20pb-1 (100 times more).
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.
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.
Conclusions • VEPP-2000started-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.
Thank you for your attention
DC resolutions R- (drift time) 100 140 m R-z (charge division)2 3 mm (dE/dx) 0.15*dE/dx
ILU CMD-3 3 MeV Linac VEPP-2000 B-3M BEP 200 MeV synchro- e+,e betatron booster 850 MeV SND 2 m 2 m ee+ convertor Nearest plans?
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 channelwillcontribute 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)KK*K KK. f0(980), , , radiation decays and physics of и mesons…
BaBar Radiation return (1450) (1570) (1420) (1650) (1680) (1700) (1900) Half statistic is processed