Feasibility of J studies by MPD detector

1
Feasibility of J/? studies by MPD detector

• Alla Maevskaya, Alexei Kurepin
• INR RAS Moscow
• NICA Roundtable Workshop
• 11 September 2009

2
Charm production at threshold

• 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!

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

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

HSD simulations
Claudia Höhne Quark Matter
Conference India, February 2008
3
Generators
CBM TSR 2005 p371
Signal 10000 J/? generated by HSD vs 7 AGeV
multiplicity 1.9?10-5 vs 9 AGeV multiplicity
8?10-5 Background 6400 central AuAu events
UrQMD vs 7 AGeV 9 AGeV
Multiplicity of D0, D, D- and J/? predicted for
central AuAu collisions as function of beam
energy by the HSD model
Alla Maevskaya INR RAS
NICA Roundtable Workshop
11 September 2009
4
Simulation environment
MpdRoot from end of May 2009 Set-up IT TPC TOF E
CAL MC tracks in TPC acceptance with Ylt1.2 Mass
resolution assumed 1
Alla Maevskaya INR RAS
NICA Roundtable Workshop
11 September 2009
5
J/? distributions for vs 9 AGeV
Registeredin TPC
HSD
momentum
transverse momentum
rapidity
Alla Maevskaya INR RAS
NICA Roundtable Workshop
11 September 2009
6
J/? distributions for vs 7AGeV
Registered in TPC
HSD
momentum
transverse momentum
rapidity
Alla Maevskaya INR RAS
NICA Roundtable Workshop
11 September 2009
7
Background sources
6400 UrQMD AuAu central events vs 9AGeV J/?
multiplicity 8x10-5
Momentum and transverse momentum of J/?
different
background sources pDalitz decay
misidentified
pions, protons and kaons
Alla Maevskaya INR RAS
NICA Roundtable Workshop 11
September 2009
8
Invariant mass spectra J/? combinatorial
background for different pions, kaons and protons
suppression factors
Suppression S/B in 3s Beam
energy 7AGeV 9AGeV protons
10000 0.55 1.5 p k
1000 protons 10000 2.0
8 p k 10000 protons 50000
3.7 12 p k 10000 J/?
efficiency 55 55
Superevent technique was used for invariant mass
of background, so 196 J/? were added to
corresponding 40960000 (6400x6400) central events
vs 9AGeV
Alla Maevskaya INR RAS
NICA Roundtable Workshop 11
September 2009
9
Conclusions
NICA will produce 400 ( or up to 1000 if MPD
efficiency wil be more than 10) J/? per 10
weeks, so during long enough run period
significant amount of particles could be
collected and studies. J/? could be measured by
MPD with existing set-up TPC, TOF and ECAL
together could provide background suppression as
needed.
Alla Maevskaya INR RAS
NICA Roundtable Workshop 11
September 2009