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Experiment NA60

Experiment NA60. Bose/Einstein Correlations. Advisors: ->Atila Neves: Lisbon, Portugal ->Sanja Damjanovic: University of Heidelberg ->Hans J. Specht: University of Heidelberg ->Hiroaki Ohnishi: Riken, Japan. Quark Gluon Plasma (QGP).

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Experiment NA60

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  1. Experiment NA60 Bose/Einstein Correlations Advisors: ->Atila Neves: Lisbon, Portugal ->Sanja Damjanovic: University of Heidelberg ->Hans J. Specht: University of Heidelberg ->Hiroaki Ohnishi: Riken, Japan David J Hover

  2. Quark Gluon Plasma (QGP) • QGP describes a new state of matter where quarks and gluons no longer exist in bound states. • QGP exists as a function of temperature and density. • Want to map out details of phase transition: • Freeze out temperature? Fireball radius? • Significance evidence shown in past SPS and offsite experiments but details still need to be confirmed.. What is the Threshold??? David J Hover

  3. Bose-Einstein Correlations (HBT) • “…intensity interferometry uses correlations between like particles induced by Fermi or Bose statistics to determine the space and time dimensions of the particle source.” • This analysis used to measure the hadronic interaction regions • Essentially a continuous double slit experiment using boson intensity instead of amplitude. • Pions are created in the same event. There are two ways to obtain the same information at the two detectors: X1 and X2. Since the two particles are indistinguishable, we must add together the two path amplitudes in order to calculate the probability. Source Detectors David J Hover

  4. Parameterize the Correlation • The correlation is observable in terms of relative momentum • S=Source, or mixed particles in same event (correlated). • B=Background, or mixed particles of different events (uncorrelated) • F(q) = Functional form described by theory • Different extracted variables (the Q coordinates): • Qs,Ql,Qo and Qinv David J Hover

  5. Correlated Data!!! • 50K dimuon triggered events binned by centrality, pair charge and target (made 2520 plots to analyze): BACKGROUND More pairs the better: decreases error but with increase in computing time. SOURCE Or Correlated Need more statistics at low relative momentum David J Hover

  6. Correlated Data C=S/B: MM is Correlated? David J Hover

  7. Corrections (1) • Momentum Resolution: • Qinv( MCgen – MCreco) • Fit with Gaussian • Extract sigma = momentum resolution = 0.023 GeV • Not Complete: • Need more MC events (more than 50K) binned in same way as data. • Once know, rerun Data with correct bin size. David J Hover

  8. Corrections (2) • Coulomb Corrections: • Correlation fit assumes particles do not correlate after production, but they do!! • Coulomb interaction reduces correlations at small relative momentums. • Solve by multiplying with Gamow factor: • Only source/same event • Both data and MCreco • Not entirely correct: • Different result at small relative momentums (overlap) • Need to check by adding into MCgen David J Hover

  9. Fit and Extract • λ=correlation factor, Rinv = Invariant Radius • I tried to minimize (Chi-Square) / ndof through grid and iterate method. • Found Rinv = 9.75 fm; λ= 0.14; Chi-Square / ndof = 3.01 • Unacceptable!! David J Hover

  10. So Much More to Do • Fix the Gamow factor. • More events. • Generate correlation and compare. • Include momentum resolution in data. • Other variables. David J Hover

  11. Many Thanks to… • NSF • Herr Jeremey • Jean Krisch • Ford • Homer Neal • My advisors • Europe • Google • French doctors • Trains that do not go through France David J Hover

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