G. Musulmanbekov, K. Gudima, D.Dryablov, V.Geger, E.Litvinenko, V.Voronyuk, M.Kapishin, A.Zinchenko, V.Vasendina Physics Priorities at NICA/MPD

What are we searching for? Signatures of phase transition and/or mixed phase Signatures of phase transition and/or mixed phase QCD critical (triple)endpoint QCD critical (triple)endpoint Onset of chiral symmetry restoration at high ρ B Onset of chiral symmetry restoration at high ρ B The equation-of-state at high ρ B The equation-of-state at high ρ B

Observables Signatures of phase transition and/or mixed phase excitation function of particle yields and ratios (π, K, Λ, Σ, Ξ, Ω) excitation function of particle yields and ratios (π, K, Λ, Σ, Ξ, Ω) transverse mass spectra of kaon transverse mass spectra of kaon particle correlations particle correlations QCD critical endpoint excitation function of event-by-event fluctuations (multiplicities, K/π, transverse momenta, …) excitation function of event-by-event fluctuations (multiplicities, K/π, transverse momenta, …) Onset of chiral symmetry restoration at high ρ B in-medium modifications of hadrons (ρ, ω, φ → e+e-(μ+μ-)) in-medium modifications of hadrons (ρ, ω, φ → e+e-(μ+μ-)) The equation-of-state at high ρ B collective flow of hadrons collective flow of hadrons particle production at threshold particle production at threshold

What have been measured at AGS, SPS and BES RHIC ? excitation function of particle yields and ratios (π, K, Λ, Σ, Ξ, Ω)? excitation function of particle yields and ratios (π, K, Λ, Σ, Ξ, Ω)? transverse mass spectra of kaon transverse mass spectra of kaon e-by-e fluctuations e-by-e fluctuations femtoscopy correlations femtoscopy correlations dilepton spectra dilepton spectra azimuthal asymmetry of particle yield azimuthal asymmetry of particle yield flows of particles flows of particles

1. Bulk properties : yield of particles, n ch, , p t, m t distributions, 2. Event-by-event fluctuations: particle ratio, net baryon (proton), p t 3. Collective flows, Reaction Plane 4. Femtoscopy correlations 5. Dileptons yield 6. Strange particle (mesons and hyperons) yield 7. Azymuthal Asymmetries: CME, CVE What is planed to measure Simulation of AuAu events for central and semicentral collisions√s = 4 – 11 GeV Models 1. Model generators: UrQMD, HSD, PLUTO, FASTMC, LAQGSM, Glauber models

Particle Yield AGS SPS

UrQMD vs Exp. Data Model Adequacy

LAQGSM vs UrQMD Model Adequacy √s = 4.7 GeV

LAQGSM vs UrQMD Model Adequacy use existing generated events produced with QGSM at √s = 5 and 9 AGeV and with UrQMD at √s = 3, 5 and 9 AGeV to estimate model dependence, 5-7k events per sample QGSM and UrQMD generate very different particle and energy flow spectra in pseudo-rapidity range of extZDC UrQMD failed to describe emission of nucleons and nuclear fragments in forward rapidities! QGSM suits for this purpose.

MPD Reconstruction efficiency √s = 4 GeV

Hyperon Study Track acceptance criterium: in TPC with |η| < 1.3 and N hits ≥ 10 “Perfect particle ID dN / dp t = p t · exp (-m t / T), where m t = √(M · M + p t · p t ), M – hyperon mass, T ~ 200 MeV dN / dy = exp (-y 2 / 2σ 2 y ), σ 2 y ≈ 0.7 Hyperon Generator MPD Reconstruction efficiency

Hyperons Study: Λ TPC + ITSOnly TPC Only TPC: Eff. ≈ 4.3% S / B (± 3σ) = 2434 / 443 ≈ 5.5 S / √(S+B) ≈ 45.4 TPC + ITS: Eff. ≈ 8.1% S / B (± 3σ) = 4310 / 468 ≈ 9.2 S / √(S+B) ≈ 62.4

Hyperons Study Ξ - TPC + ITS: Eff. ≈ 3.8% S / B (± 3σ) = 245 / 18 ≈ 13.7 S / √(S+B) ≈ 15.1 Ω - TPC + ITS: Eff. ≈ 3.8% S / B (± 3σ) = 245 / 18 ≈ 13.7 S / √(S+B) ≈ 15.1

Estimated particle yields (central AuAu collisions at √s = 9 GeV, event rate 300 Hz)‏ ParticleMultiplicityDecay ModeBRε, %Yield, s -1 Yield, 10w Λ pπ-pπ · ·10 9 Ξ-Ξ Λπ ·10 7 Ω-Ω- 7.3*10 -2 ΛK-ΛK ·10 6 Charged hyperon study with MPD looks feasible ITS significantly improves detector capabilities for such analysis

E-byE Fluctuations Theory predictions: enhancement of fluctuations near the Critical Point

Terence TarnowskyQuark Matter 2011 May 23, TPC+TOF (GeV/c): p : 0.2 < p T < 1.4 K : 0.2 < p T < 1.4 TPC+TOF includes statistical and systematic errors from electron contamination. Pion contamination of kaons < 3% using TPC and TOF. Difference between STAR and NA49 result below √s NN = 11.5 GeV. (NA49 data from C. Alt et al. [NA49 Collab.], Phys. Rev. C 79, (2009) Both models show little acceptance effects. UrQMD predicts little energy dependence. HSD predicts an energy dependence. K/pi ratio E-by-E fluctuations dyn,K/  Differences could be due to difference in acceptance and/or PID selections --- under discussion Additional check is needed!

K/pi Ratio Fluctuations Observables at MPD  dyn

Transverse Momentum Fluctuations Event mixing for the statistical background estimation: For the system of independently emitted particles fluctuation Ф p t goes to zero. No evidence for enhancement of fluctuations!, where

Femtoscopy correlations of pions Reconstruction of Correlation functions in central AuAu collisions at √s = 9 GeV

Reaction Plane Resolution Reaction Plane Resolution By elliptic flow in TPC Resolution vs centrality at √s = 9 GeV Resolution vs collision energy NICA/MPD results are comarable with STAR data

Event Plane Reconstruction at STAR with Directed Flow: 1 STAR Resolution  Event plane measurements at STAR: (1)TPC(|η| ≤ 1) (2) (3) BBC(3.8 ≤ |η| ≤ 5.2)

Reaction Plane Resolution Reaction Plane Resolution With direct flow in ExtZDC Resolution vs centrality at √s = 9 GeV Extended ZDC detector (2.2<η<4.8) can measure RP with resolution of δφ RP ~22 o -30 o at medium b (4<b<10 fm for 9 GeV AuAu), which is much more better then TPCs at NICA and TPC and BBC at STAR can give!

Which measurements could be preferable in NICA energy region Enhanced yield of positive and neutral kaons near threshold. Enhanced yield of one, double and triple strange baryons near threshould. Correlation of kaons with hyperons Elliptic and direct flows of hyperons Polarization of hyperons Enhanced mass spectra of dileptons Polarization of dileptons

Thank you for your attention!