M ixed P hase D etector ( MPD )

1. MPD Mixed Phase Detector (MPD) Joint Institute for Nuclear Research Conceptual project S.Afanasiev, V.Babkin, A.Baldin, S.Bazylev, V.Borisov, D.Driablov, V.Golovatyuk, A.Isupov, V.Krasnov, V.Ladygin, A.Litvinenko, Ju.Lukstinsh, A.Malakhov, E.Matyushevskiy, I.Migulina, N.Piskunov, E.Plekhanov, A.Shabunov, S.Shimansky, I.Slepnev, V.Slepnev, I.Tyapkin, S.Vokal, Yu.Zanevsky, P.Zarubin, L.Zolin. 6-7 October 2006 Dubna, Russia

2. MPD • Experimental setup should allow to measure: • - Event-by-event fluctuations. The hadron yields and momentashould be analyzed event-wise in order to search for strongfluctuations which are predicted to occur in the vicinity of thecritical endpoint and when penetrating the coexistence phase (themixed quark-hadron phase) of the first order deconfinement phasetransition. In order to subtract the (dominant) contributions fromresonance decays one should measure the yields of the relevantshort-lived hadron resonances. • - Multistrange hyperons.The yields, spectra and collectiveflow of (multi) strange hyperons are expected to provideinformation on the early and dense phase of the collision as theyare produced close to threshold. Therefore, these particles arepromising probes of the nuclear matter equation of state at highbaryon density. • - HBT correlations. Observation of short correlations ofπ, K, p, Λ hadrons allows one to estimate thespace-time size of a system formed in nucleus-nucleusinteractions. Alongside with the increase of fluctuations, thespatial size of the system is expected to be enhanced at the phase transition getting smaller nearthe deconfinement point due to softening the equationof state (the "softest point" effect). • - Penetrating probes. Measurements of dilepton pairspermitto investigate the in-medium spectral functions of low-mass vectormesons which are expected to be noticeably modified due to effects of chiralsymmetry restoration in dense and hot matter. Specific propertiesof the σ-meson as a chiral partner of pions, whichcharacterizes a degree of chiral symmetry violation, may be inprinciple detected near the phase boundary via a particularchannel of σ-decay into dileptons or correlatedγγ-pairs. Above a beam energy of about 15 AGeV alsocharmonium might be detectable. J/Ψ mesons are a promisingprobe for the deconfinement phase transition. • - Open charm. D-mesons probe the early phaseof the collision and are sensitive to in-medium effects due tochiral symmetry restoration. 6-7 October 2006 Dubna, Russia

3. MPD Setup overview Scheme of the MPD setup. TPC - Time Projection Chamber; SVS - Silicon Vertex tracking System; TRD - Transition Radiation Detectors; TOF - Time of Flight detectors; EC - Electromagnetic Calorimeters; LENS - magnetic focusing lens of collider 6-7 October 2006 Dubna, Russia

4. MPD 6-7 October 2006 Dubna, Russia

5. MPD Main components of proposed MPD setup: - Superconductive Magnet System (MAGNET COILS); - Vertex tracking System; - Central Arm; - Two Forward arms; Each Arm include Time Projection Chamber (TPC); Transition Radiation Detectors (TRD); Time of Flight detectors (TOF); Electromagnetic Calorimeters (EC). 6-7 October 2006 Dubna, Russia

6. MPD 6.2 Superconductive Magnet System The superconductive magnet system is composed by two pairs of concentric coils and provides a field (1-2T) parallel to the beam. For the forward angle, the magnetic field is formed by iron cones and produces a radial magnetic field for the forward angle analysis. The primary physics-driven requirements for the central magnet design are: (i) No mass in the apertures of the spectrometer arms to minimize interactions and multiple scattering of particles produced in the primary collision and to minimize albedo from the magnet poles. (ii) Dense material near the collision point in the apertures of the forward arms to serve as hadron absorbers. (iii) Reasonably uniform field that could be mapped to a precision in the field integral of about 2 parts in 1000. (iv) Control over the radial field distribution to allow creation of a "zero field" region near R = 0. (v) Minimal field integral for the region R > 200 cm, the radius of the TPC. Field in the region of the photomultiplier tubes of the TOF and the Electromagnetic Calorimeter are also required to be low. (vi) The magnet must be easily moveable to allow access to detector components for commissioning, maintenance and replacement. 6-7 October 2006 Dubna, Russia

7. MPD Silicon Vertex tracking System(SVS); The vertex tracking is based on highly segmented silicon pixel and microstrip detectors at mid-rapidity, and further silicon pixel detectors in the forward direction. Three internal central layers of SVS are constructed from silicon pixel detectors and three outer layers are built from microstrip silicon detectors with a pitch from 25 to 50 mkm. They will be arranged in two half-shells and will cover approximately −5o<<40o and almost 2 in azimuth. Pixel sensor technology is essential for the resolution of the high track density in heavy ion collision in the internal layer. Microstrip detectors also could be used in the more outward layers where the occupancies are less severe. The forward silicon detectors will consist of four pixel cones per side that match the geometrical acceptance 6-7 October 2006 Dubna, Russia

8. MPD Tracking System A large Time Projection Chamber (TPC) is proposed as a main tracking device for the detector at future collider. The ambitious physics program poses unprecedented requirements on the precision of the TPC. This modern experiments plan to use TPC at high charged particles multiplicities of up to 800 per event. The modern experiments are propose to work at unprecedented high multiplicities up to 8000 per unit rapidity - ALICE TPC (CERN/LHCC 2000–001). Another example of the tracking system is the STAR TPC which is able routinely reconstructs more than 3000 tracks per one event (M.Anderson et al., Nucl.Instr.Meth.A499 (2003) 659). TPC operation parameters Centarl TPC - diameter = 5.6m - lenght = 2.0m Forward TPC - diameter 1 = 1.5m diameter 2 = 5.0m - lenght = 2.0m Drift time -=50s 6-7 October 2006 Dubna, Russia

9. MPD A L I C E TDR of the Time Projection Chamber The STAR TPC The STAR detector contains a large, cylindrical, Time Projection Chamber (TPC) as its primary detector element. The TPC has an active volume that extends from -1.8 to +1.8 units of pseudo-rapidity with full azimuthal coverage. It sits inside a large solenoidal magnet which is designed to run with a .eld between 0 and 0.5 T. The event multiplicities excess of 3000 tracks per event. The momentum resolution is 2% at 500 MeV/c: The two-track resolution for HBT pairs of tracks is 2.5 cm. The dE=dx resolution is Excellent It able to separate the pion band and the proton band at momenta up to 1.3 GeV/c and the resolution is 7.5%. To cover this acceptance the TPC is of cylindrical designwith an inner radius of about 80 cm, an outer radius of about 250 cm, and an overall length in the beam direction of 500 cm. Two-track resolution: a resolution in relative momentum of a few (_ 5) MeV/c can be performed. Resolution in dE/dx: For hadron identification a dE/dx resolution of 8% is desirable, following the experience of NA49. Track matching capability to ITS and TOF: Should be 85%–95%. Electronics: At about 570 000 channels the front-end electronics 6-7 October 2006 Dubna, Russia

10. MPD 6-7 October 2006 Dubna, Russia

11. MPD Particle identification with TPCAn strength of the tracker in solenoid magnetic field at MPD is a large and uniform acceptance capable to measure and to identify substantial fraction of the particles produced in heavy-ion collisions. For stable charged hadrons, the TPC provides pions and kaons (protons) identification up to pt ~ 0.7 (1,1) GeV/c by ionization energy loss (dE/dx). A TOF system with a time resolution of <100 ps is able to identify pions and kaons (protons) up to pt ~ 1.6 (3.0) GeV/c, as demonstrated in Fig.. Combination of dE/dx in the TPC and velocity measurements by TOF provides a strong tool for the dilepton measurements. 6-7 October 2006 Dubna, Russia

12. MPD TRD Straw tubes MWPC The Transition Radiation Detector (TRD) will provide, in conjunction with data from the TPC and EC detectors, sufficient electron identification to measure, in the dielectron channel, the production of light and heavy vector-meson resonances for U-U collisions at the NICA, as well as allow to study the dilepton continuum. In addition, the electron identification provided by the TPC and TRD at relatively large transverse momenta (pt1 GeV/c) can be used, in conjunction with the impact-parameter determination of electron tracks in the ITS, to determine the overall amount of open charm and open beauty produced in the collision. With a similar technique one can also separate directly produced J y mesons. TRD system Design goals e/π discrimination of > 100 (p > 1 GeV/c) High rate capability up to 150 kHz/cm2 Position resolution of about 200 μm. Large area ( 50m2, 3 layers) 6-7 October 2006 Dubna, Russia

13. MPD Electromagnetic Calorimeter. (EC) Lead-Scintillator Calorimeter The Pb-scintillator electromagnetic calorimeter is a shashlik type samplingcalorimeter made of alternating tiles of Pb and scintillator consisting of 1500 individual towers and covering an area of approximately 18 m2. The basic building block is a module consisting of four (optically isolated) towers which are read out individually. The PbSc calorimeter has a nominal energy resolution of 8.1%/E(GeV ) +2.1% and an intrinsic timing resolution better than 200 ps for electromagnetic showers 6-7 October 2006 Dubna, Russia

14. MPD ZDC 6-7 October 2006 Dubna, Russia

15. MPD Table 8.4. Schedule of MPD group II realization 6-7 October 2006 Dubna, Russia

16. MPD 6-7 October 2006 Dubna, Russia

17. MPD Summary Mixed Phase Detector (MPD) • - operate at the energy of beams 2.5 x 2.5 GeV/u; • - work at the luminosity of the heavy ion beams up to 1027 cm-2s-1 for U+U; • - has practically 4 geometry; • - has minimum of passive matter in the detector volume; • - allow to measure high multiplicity events, up to 1000 particles/event; • - to separate e, , K, p particles in range 200<P<2000 MeV/c; • - to measure lepton-pairs and -pairs; • This setup can be use for solution offundamental scientific questions : • the nuclear matter equation-of-state at high baryonicdensities; • the in-medium properties of hadrons; • space-time evolution of nuclear interaction; • the phase transitions; • the QCD critical endpoint; • +Polarization studies at new facility 6-7 October 2006 Dubna, Russia

18. MPD Thanks for attention! 6-7 October 2006 Dubna, Russia

19. MPD 6-7 October 2006 Dubna, Russia