Presentazione di PowerPoint
1 - Onset of deconfinementNA60+ - Existence (or non existence)
of QCD critical point - Chiral symmetry restorationMeasuring
dimuons at different energies in the range 20-160 AGeV and with
different collision systems: Simulation studies for the apparatus
setup (PRIN 2009): - acceptances - rec eff - mass resolution -
rates1
First order transition and onset of deconfinementFull circles:
early stage of systems created in central Pb-Pb collisions at
different energies at sNN = 6.3 , 7.6, 8.7 and 12.3 GeV (NA49 PbPb,
AGS AuAu)
Systems cool and expand evolving along the solid lines to the
freeze-out points (squares and triangles)
The magenta circle might lie on the first order transition line
marking the onset of deconfinement QCD phase diagram poorly known
in the region of highest baryon densities and moderate temperatures
is there a critical point?
Critical point(s) search
Search for the critical pointEnergy interval covered by SPS:
fundamental for search of CPRequires a bidimensional scan in energy
and collision systemAccelerator landscape Beam conditions: CERN vs.
GSI/FAIRLuminosity at the SPS comparable to that of SIS100/300 No
losses of beam quality at lower energies except for emittance
growth RP limits at CERN in EHN1, not in (former) NA60 cave < 11
35 (45) SPS SIS100/300 beam target interaction intensity thickness
rate2.5106 5105 [i ] [Hz] [Hz] 20% NA60 (2003) new injection scheme
108 10% 107 108 1% 106 interaction rate [Hz] 105 - 107Energy range:
10 158 [AGeV] LHC AA 5104 Pb beams scheduled for the SPS in
2016-2017, 2019-2021 H.J.Specht, ECT* Trento 2013
qqCharacteristic regimes in invariant m+m- mass, M2=(pe++ pe- )2
: Drell-Yan: power law ~ Mn thermal ~ exp(-M/T): - QGP - HG (4p
processes)Measuring dileptons in the IMR region~ exponential
fall-off Planck-like M>1 GeV
fit to T>Tc: partons dominaterange 1.1-2.0 GeV: T=20512 MeV
1.1-2.4 GeV: T=23010 MeV
Evolution of yield and T vs beam energy
QGP spectrum using a lattice-QCD constrained rate (Rapp et
al.)hadronic spectrum using the in-medium r+w+4p spectral function
(Rapp et al.)PbPb 40 AGeV 0-5% central collisionsQGP fraction still
relevant even at 20-40 AGeV?
Measure evolution of yield and temperature vs beam energyIn-In
160 AGeV dNch/dh>30 6
pT spectra nearly thermal
Fit with dN/dpT=pTexp(-MT/T) in 50 MeV mass bins (using 107 ev
MC sample) HG radiationQGP radiation
mass spectrum: T = 20512 MeV pT spectra: = 19012 MeV M >1 GeV
T = 205 MeV > Tc = 170 (MeV) - Teff independent of mass within
errors - same values within errors negligible flow soft EoS above
Tc all consistent with partonic phase Transverse momentum spectra:
evolution of Teff vs beam energyPbPb 40 AGeV 0-5% central
collisions (Rapp et al.)Measure the evolution of Teff vs mass vs
beam energy
Phys. Rev. Lett. 91 (2003) 042301Higher baryon density at 40
than at 158 AGeVEnhancement factor:5.91.5(stat.)1.2(syst.)
(published 1.8 (syst. cocktail) removed due to the new NA60
results on the and FFs)Larger enhancement in support of the
decisive role of baryon interactions Measuring the rho regionLarge
enhancement: might not be just coincidental with expectation of
emergence of CPOnly one exisiting measurement at 40 AGeV with very
low statistics
Muon spectrometerToroid field (R=160 cm)beam5 m9Compress the
spectrometer reducing the absorber and enlarge transverse
dimensionsdimuons@160 GeV (NA60) rapidity coverage 2.9