Understanding J/ Ψ Suppression Cold Nuclear Matter (CNM) extrapolations from p(d)+A to A+A

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5/25/2009 Mike Leitch 1 Understanding J/Ψ Suppression Cold Nuclear Matter (CNM) extrapolations from p(d)+A to A+A

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Understanding J/ Ψ Suppression Cold Nuclear Matter (CNM) extrapolations from p(d)+A to A+A. Present (PPG078) CNM Constraints on A+A data. R AA. - PowerPoint PPT Presentation

Transcript of Understanding J/ Ψ Suppression Cold Nuclear Matter (CNM) extrapolations from p(d)+A to A+A

  • 5/25/2009Mike Leitch*Understanding J/ Suppression

    Cold Nuclear Matter (CNM) extrapolations from p(d)+A to A+A

    Mike Leitch

  • Present (PPG078) CNM Constraints on A+A dataCNM effects (EKS shadowing + dissociation from fits to d+Au data, with R. Vogt calculations) give large fraction of observed Au+Au suppression, especially at mid-rapiditymore accurate d+Au constraint soon from 2008 datad+Ausmall-x(shadowing region)PRC 77,024912(2008)RdAu5/25/2009*Mike Leitch& Erratum: arXiv:0903.4845

    Mike Leitch

  • New 2008 d+Au J/ data - RCPInitial d+Au J/ update from new 2008 data (~30x 2003)

    RCP pretty flat vs centrality at backward rapidity; but falls at forward rapidity (small-x)

    more soon precision statistics requires precision systematics & careful analysisEKS = 0,1,2,3,4,155/25/2009*Mike Leitch

    Mike Leitch

  • 6/24/2009Mike Leitch* similar to before, use models with shadowing & absorption/breakup but allow effective breakup cross section to vary with rapidity to obtain good description of data for projections to A+A

    get breakup(y); compare to E866/NuSea & HERA-B Lourenco, Vogt, Woehri - arXiv:0901.3054

    common trend, with large increasing effective breakup cross section at large positive rapidity need additional physics in CNM model e.g. initial-state dE/dxwith EKS shadowingwith NDSG shadowingNew CNM fits using 2008 PHENIX d+Au Rcp

    Mike Leitch

  • 6/24/2009Mike Leitch*Cross Check - Comparision of New Effective Breakup Cross Section fits to published 2003 d+Au RdAu ResultsFairly consistent with RdAu from old 2003 data PRC 77,024912(2008)

    Mike Leitch

  • 6/24/2009Mike Leitch*Survival Probability after dividing out CNM extrapolationThe relation between the charged multiplicity and NPart is obtained AuAu using PHOBOS data(Phys.Rev.C65 061901 (2002)

    PbPb using NA50 data(Phys.Lett.B 530 1-4 (2002) 43-55) Good agreement between PbPb and AuAuResults are shown as a function of a the multiplicity of charged particles (~ energy density, assuming SPS~RHIC)

    Mike Leitch

  • 5/25/2009Mike Leitch* Both Pb-Pb and Au-Au seem to depart from the reference curve at NPart~200

    For central collisions more important suppression in Au-Au with respect to Pb-PbMeasured/Expected SPS results are compared with AuAu RHIC RAA results normalized to RAA(CNM)Comparison with new RHIC results

    Mike Leitch

  • 5/25/2009Mike Leitch*Open Charm Nuclear Dependence from FNAL-E789/E866

    Mike Leitch

  • 6/24/2009Mike Leitch*Fermilab E789: D0 & B J/ X(charm & beauty using silicon)Dimuon spectrometer+16-plane, 50m pitch/8.5k strip silicon vertex detectorupstreamdownstreamB J/ + X

    Mike Leitch

  • 6/24/2009Mike Leitch*E866/NuSea Open Charm MeasurementDumpTargettarget dump hadronic cocktail explains ~30% of target &
  • 6/24/2009Mike Leitch*Rapidity dependence of open charmOpen-charm p+A nuclear dependence (single- pT > 1 GeV/c) very similar to that of J/ dominant effects are in the initial state e.g. shadowing, dE/dx, Cronin weaker open-charm suppression at y=0 attributed to lack of absorption for open charmE866/NuSea 800 GeV p+A

    Mike Leitch

  • 6/24/2009Mike Leitch*

    Mike Leitch

  • 5/25/2009Mike Leitch*

    Mike Leitch

  • PHENIX Au+Au data shows suppression at mid-rapidity about the same as seen at the SPS at lower energy but stronger suppression at forward rapidity. Forward/Mid RAA ratio looks flat above a centrality with Npart = 100

    Several scenarios may contribute: Cold nuclear matter (CNM) effects important, need better constraint Sequential suppression QGP screening only of C & - removing their feed-down contribution to J/ at both SPS & RHIC Regeneration models give enhancement that compensates for screeningPHENIX A+A Data and FeaturesCentrality (Npart)5/25/2009*Mike Leitch

    Mike Leitch

  • Looking for the cold nuclear matter baseline for J/ production at RHIC

    Tony FrawleyFlorida State University

    ECT, TrentoMay 26, 2009

  • May 26, 2009Tony Frawley, FSU*

    Many thanks for contributions/help from:

    Ramona VogtMike LeitchAlex Linden LevyJamie NagleDarren McGlinchey

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*The quarkonium plan

    SpeciesPurpose

    p+pQuarkonium production mechanismsBaseline cross sections for heavy ions

    d+Au Cold nuclear matter effectsBaseline CNM RAA for heavy ions

    Cu+CuHot nuclear matter effects near TC

    Au+AuHot nuclear matter effects well above TC

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*The PHENIX Detector

    J/e+e--0.35 < y < 0.35J/+-1.2 < |y| < 2.2

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Brief review of the relevant J/ data

    Au+Au RAARun 4 Au+Au+ Run 5 p+p

    Cu+Cu RAARun 5 Cu+Cu + Run 5 p+p

    d+Au RCPRun 8 d+Au

    To come: Run 8 RdAu with Run 6 pp reference

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Reference data Run 5 p+p

    PHENIX, PRL98, 2002 (2007)This is the reference data set for all nuclear modification factors shown here.

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Cu+Cu and Au+Au RAA

    Phys. Rev. Lett. 101, 122301 (2008)The Npart dependence of Au+Au and Cu+Cu is consistent.

    Note the smaller systematic uncertainties for the Cu+Cu data. This is primarily due to smaller uncertainties on Ncoll from the Glauber calculation.

    Thus the Cu+Cu data will be much better for studying the onset of hot nuclear matter effects.

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Au+Au RAA

    PHENIX reference hereThe stronger Au+Au suppression at forward/backward rapidity has generated considerable interest.

    But what is the expected suppression due to cold nuclear matter effects?

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*d+Au RCP

    The first results for d+Au from Run 8, shown at QM09.

    Four centrality bins to make three RCP points:

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*What can we learn from the existing charmonium RAA data?

    The heavy ion charmonium data alone have not taught us as much as we would like, because of serious uncertainties caused by:

    1) Poorly known initial state effects at RHIC: Break up cross section for collisions with nucleons. Shadowing. Other effects? Initial state energy loss?

    2) Poorly known open charm production cross sections.

    Thus the trade-off between coalescence and destruction is difficult to illuminate experimentally.

    To try to make inroads on 1), we start from the most recent d+Au data set: Run 8 d+Au

    First we briefly review previous attempts to use Run 3 d+Au data for this.

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Estimating the CNM RAA from Run 3 d+Au data - 1

    This has been done before in three ways:

    1) PHENIX (Phys. Rev. C 77, 024912 (2008) and erratum arXiv:0903.4845) fitted Run 3 RdAu using a single breakup at all rapidities + EKS98/nDSg shadowing calculations by Ramona Vogt.

    The CNM RAA was estimated using calculations of RAA for Cu+Cu and Au+Au by Ramona, using the fitted breakup + EKS98/nDSg.

    However (Phys. Rev. Lett. 101, 122301 (2008)PPG071), when a single breakup is used at all rapidities the ratio of the predicted y=0 to |y|=1.7 CNM RAA values is just a prediction of the shadowing model. Therefore this is not a good way to use the RdAu data to test if the increased suppression at |y|=1.7 is due to CNM effects.RAA

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Estimating the CNM RAA from Run 3 d+Au data - 2

    2) Raphael Granier de Cassagnac (J. Phys. G34, S955 (2007)) used direct folding of the RdAu data, with some assumptions, to predict the CNM RAA for Au+Au. This works only for Au+Au, since RdAu is used directly.

    This approach produces completely independent CNM RAA values at y=0 and |y|=1.7 which is very good. But because of the low statistical precision of the Run 3 d+Au data, the results are inconclusive.

    This approach cannot be used with d+Au RCP data, nor can it be used to estimate a CNM RAA baseline for Cu+Cu.

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Estimating the CNM RAA from Run 3 d+Au data - 3

    Phys. Rev. Lett. 101, 122301 (2008)

    3) The PHENIX RdAu data were fitted separately at y=0 and |y|=1.7 with breakup + EKS98/nDSg calculations by Ramona. The CNM RAA was predicted for Cu+Cu and Au+Au independently at y=0 and |y|=1.7 using calculations by Ramona.

    While this makes the ratio of the estimated CNM RAA at y=0 and |y|=1.7 sensitive to the RdAu data, it still assumes the forward and backward rapidity data have the same breakup. We will see this is not justified.

    NOTE: The uncertainty bands here are underestimated due to the fitting error that was corrected for 1). Not fixed here yet!

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Fitting the Run 8 d+Au RCP

    We want to parameterize the d+Au RCP data so that we can predict the heavy ion RAA that would result from p+A physics only.

    Fit RCP vs centrality independently at each rapidity using calculations of RdAu vs impact parameter by Ramona Vogt that include: breakup for collisions of (forming) J/ with nucleons (0-15 mb, 1 mb steps). A shadowing model EKS98 and nDSg are used here.

    Convert RdAu vs impact parameter to RdAu vs centrality using PHENIX Glauber impact parameter distribution for each dAu centrality bin.

    Fit procedure: Fit RCP vs centrality using only uncertainties that are uncorrelated in rapidity. Vary RCP by +/- 1 in uncertainties that are correlated in rapidity, and refit. Vary RCP by +/- 1 in uncertainties that are global with rapidity and refit.Uncertainties are shown respectively as bars, boxes, and a global number.

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Fits to d+Au RCP example for EKS98

    Integrated for each muon arm

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*breakup vs y from d+Au RCP fits with EKS98 and nDSg

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Comparison with lower energy data EKS98 fits

    Lourenco, Vogt and Woehri (JHEP 02 (2009) 014) published the effective breakup cross section vs y from fits to E866 and HERA-B data.

    Our results from 200 GeV are shown here compared with their results for the EKS98 case.

    For y > 1.2 the 200 GeV data follow the trend observed at lower energy remarkably closely!

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Comparison with lower energy data nDSG fits

    Note that the effective breakup cross section is significantly lower for y < 1.2.

    But for y > 1.2 there is little difference from the EKS case.

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Sanity check! Comparision of new effective breakup cross section fits from RCP to published 2003 d+Au RdAu resultsFrom the talk by Mike Leitch.

    Fairly consistent with centrality integrated RdAu from old 2003 data PRC 77,024912(2008)

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Parameterize d+Au RCP at |y|= 0, 1.7 EKS98

    Integrated for each muon arm

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Effective breakup used in Glauber calculations |y| = 0, 1.7

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Cold Nuclear Matter RAA for heavy ions

    Having calibrated the Vogt calculations at each rapidity, we estimate the CNM RAA using the results from the dAu RCP fits.

    To do this, we use a Glauber calculation for Au+Au that reproduces well the average Npart and Ncoll values for the centrality bins used by PHENIX.

    In the Glauber calculation:Each nuclear collision is placed in a centrality bin according to Npart. For each nucleon-nucleon collision: Determine impact parameter b1 of nucleon 1 in its target nucleus. Determine impact parameter b2 of nucleon 2 in its target nucleus. Add to the accumulated RAA: RdAu(b1,y=0) * RdAu(b2,y=0) Add to the accumulated RAA: RdAu(b1,y=-1.75) * RdAu(b2,y=1.75)

    After processing all events, print out at y=0 and y=1.7 for centrality bin j: Nevts[j], (RAA[j])/Nevts[j], (Ncoll[j])/Nevts[j], (Npart[j])/Nevts[j]

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Estimation of uncertainties

    The CNM RAA is calculated for the central fitted breakup and for +/- 1 in the type A (uncorrelated in rapidity) uncertainty and for +/- 1 in the type B (correlated in rapidity) uncertainty.

    The type A uncertainty is shown as a vertical bar, and the type B as a box.

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Heavy ion CNM baseline RAA EKS98 parameterization

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Heavy ion CNM baseline RAA nDSg parameterization

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Calculating the heavy ion RAA survival probability

    Now we can calculate the ratio RAA/RAA(CNM) from the measured RAA and the estimated RAA(CNM) shown on the previous slides.

    In the following plots the uncertainty in RAA/RAA(CNM) due to the uncorrelated (mostly statistical) uncertainty in the measured RAA is shown as a bar, the correlated uncertainty in the measured RAA us shown as a narrow box, and the uncertainty due to the estimated CNM RAA is shown as a wider box.

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Heavy ion survival probability at y=0 (EKS example)

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Heavy ion survival probability at |y| = 1.7 (EKS example)

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Heavy ion survival probability - EKS98 parameterization

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Heavy ion survival probability - nDSg parameterization

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Comments

    We are just starting to try to understand the d+Au data and their implications for heavy ions. Keep several things in mind about what was done here:

    We assume that we can isolate hot nuclear matter effects by calculating RAA due to a (Glauber guided) superposition of d+Au collisions. Perhaps not!

    The role of Glauber uncertainties (mostly Ncoll) needs to be understood in detail. The systematic uncertainties should be considered tentative until then.

    We believe that fitting the RdAu data, rather than RCP, will provide greater precision when estimating the CNM baseline RAA for Au+Au and Cu+Cu.

    Although the parameterization at each rapidity is precise, it would be more satisfying if the model worked well over the full d+Au rapidity range!

    We need to repeat this exercise for the Cu+Cu data (easy enough to do, did not have time yet).

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Summary

    The PHENIX d+Au data at 200 GeV seem to follow the trend observed at lower energy of a rapid rise in the effective breakup at forward rapidity.

    The effective breakup appears to be roughly constant below y ~ 1.25 at 200 GeV.

    The RAA(CNM) estimated from the fits to the RdAu data show significantly stronger suppression at |y|=1.7 than at y=0.

    The measured suppression beyond the estimated RAA(CNM) values, presumably due to hot nuclear matter effects, seems to be very similar at y=0 and |y|=1.7 at about 50%.

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*What next

    Calculate RAA(CNM) for Cu+Cu.

    Investigate the transverse momentum dependence.

    Understand the role of Ncoll uncertainties better.

    Do it all again with RdAu instead of RCP.

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Backup

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*EPS08 parameterization

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Existing RHIC Data - Au+Au

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Existing RHIC Data - Cu+Cu

    Tony Frawley, FSU

  • May 26, 2009Tony Frawley, FSU*Reference data: Run 6 p+p will be used for RdAu

    The best p+p data set that has been analyzed so far is from Run 6.

    Tony Frawley, FSU

    Update to Erratum plots****************************************