Feasibility of J/Feasibility of J/ψψ studies by MPD studies by MPD detectordetector Alla Maevskaya, Alexei KurepinAlla Maevskaya, Alexei KurepinINR RAS MoscowINR RAS Moscow

NICA Roundtable WorkshopNICA Roundtable Workshop11 September 200911 September 2009

2

Charm production at thresholdCharm production at threshold

[W. Cassing et al., Nucl. Phys. A 691 (2001) 753]

HSD simulations

• CBM (NICA) will measure charm production at threshold

→ after primordial production, the survival and momentum of the charm quarks depends on the interactions with the dense and hot medium!

→ direct probe of the medium!

charmonium in hot and dense matter?• relation to deconfinement?• relation to open charm?

Claudia Höhne Quark Matter Conference India, February 2008Claudia Höhne Quark Matter Conference India, February 2008

GeneratorsGeneratorsSignal:Signal:

10000 J/10000 J/ψψ generated by HSD generated by HSD

√√s = 7 AGeV multiplicity 1.9s = 7 AGeV multiplicity 1.91010-5-5

√√s = 9 AGeV multiplicity 8s = 9 AGeV multiplicity 81010-5-5

Background :Background :

6400 central Au+Au events 6400 central Au+Au events UrQMDUrQMD

√√s = 7 AGeV & 9 AGeVs = 7 AGeV & 9 AGeV

Alla Maevskaya INR RAS NICA Roundtable Workshop 11 September 2009

Multiplicity of DMultiplicity of D00, D, D++, D, D-- and J/ and J/ψψ predicted for central Au+Au predicted for central Au+Au collisions as function of beam collisions as function of beam energy by the HSD modelenergy by the HSD model

[CBM TSR 2005 p371]

Simulation environmentSimulation environmentMpdRoot from end of May 2009 MpdRoot from end of May 2009

Set-up:Set-up:

ITIT

TPCTPC

TOFTOF

ECALECAL

MC tracks in TPC acceptanceMC tracks in TPC acceptance

with Y<1.2with Y<1.2

Mass resolution assumed 1%Mass resolution assumed 1%

Alla Maevskaya INR RAS NICA Roundtable Workshop 11 September 2009

J/J/ψψ distributions for √s = 9 AGeV distributions for √s = 9 AGeV

momentummomentum transverse transverse momentummomentum

rapidityrapidity

Alla Maevskaya INR RAS NICA Roundtable Workshop 11 September 2009

HSDHSD RegisteredRegisteredin TPCin TPC

J/J/ψψ distributions for √s = 7AGeV distributions for √s = 7AGeV

momentummomentum transversetransverse momentummomentum

rapidityrapidity

Alla Maevskaya INR RAS NICA Roundtable Workshop 11 September 2009

HSDHSD Registered Registered in TPCin TPC

Background sourcesBackground sources6400 UrQMD Au+Au central events √s =9AGeV 6400 UrQMD Au+Au central events √s =9AGeV J/J/ψψ multiplicity ~8x10 multiplicity ~8x10-5-5

Alla Maevskaya INR RAS NICA Roundtable Workshop 11 September 2009

Momentum and transverse momentum of Momentum and transverse momentum of J/J/ψψ different background sources: different background sources: ππ°Dalitz decay°Dalitz decay; ; misidentified misidentified pionspions, , protons protons and and kaonskaons

Invariant mass spectra J/Invariant mass spectra J/ψψ + combinatorial + combinatorial background for different pions, kaons and background for different pions, kaons and

protons suppression factorsprotons suppression factorsSuppression S/B in 3Suppression S/B in 3σσBeam energyBeam energy 7AGeV 9AGeV7AGeV 9AGeVprotons 10000 0.55 1.5protons 10000 0.55 1.5ππ & k & k 1000 1000

protons 10000 2.0 8protons 10000 2.0 8ππ & k & k 10000 10000protons 50000 3.7 12protons 50000 3.7 12ππ & k & k 10000 10000

J/J/ψψ efficiency 55% efficiency 55% 55%55%

Alla Maevskaya INR RAS NICA Roundtable Workshop 11 September 2009

Superevent technique was used for invariant mass of background, so 196 Superevent technique was used for invariant mass of background, so 196 J/J/ψψ were added to corresponding 40960000 (6400x6400) central events were added to corresponding 40960000 (6400x6400) central events √s =9AGeV√s =9AGeV

ConclusionsConclusions

NICA will produce ~400 NICA will produce ~400 ( or up to 1000 if MPD ( or up to 1000 if MPD efficiency wil be more than 10%)efficiency wil be more than 10%) J/ J/ψψ per 10 weeks, so per 10 weeks, so during long enough run period significant amount of during long enough run period significant amount of particles could be collected and studies.particles could be collected and studies.

J/J/ψψ could be measured by MPD with existing set-up: could be measured by MPD with existing set-up: TPC, TOF and ECAL together could provide TPC, TOF and ECAL together could provide background suppression as needed.background suppression as needed.

Alla Maevskaya INR RAS NICA Roundtable Workshop 11 September 2009