New cold nuclear matter constraints from J/ψ suppression in d+Au at PHENIX L. A. Linden Levy for the PHENIX collaboration lindenle@colorado.edu Department of Physics 390 UCB University of Colorado Boulder, CO 80309-0390

Why heavy quarkonia? J/ψ was predicted as an excellent QCD thermometer. Heavy quark anti-quark pairs allow potential models. Different states have different binding energies (radii) as the pair is screened they dissociate. → Color Debye screening. (Matsui and Satz). Corollary: The picture of sQGP has become even more complicated Cold Nuclear Matter effects Recombination of uncorrelated heavy flavor. LQCD predictions of correlations T>TC. Gluo-disassociation Detailed balance of J/ψ depletion and restoration is necessary. 1.2 TC A. Mocsy 9/22/2018 WWND, Jamaica

PHENIX Coordinate System South Arm Central Arm North Arm Au d 200GeV d+Au collisions. Di-Muons recorded via MuTr and MuID in N. & S. arm. Di-Electrons from Central arm PC, DC, EMCal and RICH. 9/22/2018 WWND, Jamaica

Nuclear modification factor. Suppression due to normal density nuclear matter in d+Au 200GeV (RHIC 2003) Baseline p+p 200GeV data (RHIC 2005) Forward Mid Backward d Au Phys Rev C 77, 024912 Au d 9/22/2018 WWND, Jamaica

Quantitative comparison vs. centrality. Ncoll dependence of the model from a Glauber inspired geometric model. (R. Vogt hep-ph 0411378)‏ Breakup cross section is a free param. CEM model for x1,x2 (R. Vogt) Woods-Saxon density profile for Au. 9/22/2018 WWND, Jamaica

More about fitting…. Type A: point to point uncorrelated (bars) Phys Rev C 77, 024912 Type A: point to point uncorrelated (bars) Type B: point to point correlated (boxes) Type C: global (relative) PRC77 064907 9/22/2018 WWND, Jamaica

Breakup cross section NDSG σ = 0 mb σ = 4 mb EKS σ = 0 mb σ = 4 mb 2008 d+Au J/ψ results from PHENIX Systematics cancel within a run. ~15X statistics of 2003 data set. Expect a reduction in the Type A error of ~1/√2. First look at shadowing predictions based on nPDF calculation (R. Vogt private communication). Still interpreting the data: no sigma breakup best value yet. Expect a a PRL publication in the near future. NDSG σ = 0 mb σ = 4 mb EKS σ = 0 mb σ = 4 mb EPS08 σ = 0 mb σ = 4 mb Difficult to account for the forward rapidity with a breakup cross section ~0. Or something completely different… 9/22/2018 WWND, Jamaica

√s=40GeV Other physics at work? Note: E866 has x2 range is ~ 0.01-0.1 near the crossover from shadowing to anti-shadowing. 9/22/2018 WWND, Jamaica

Quantitative Extraction @ Fixed y RCP Npart 9/22/2018 WWND, Jamaica

Rapidity dependence! Extract best fit to RCP at a given rapidity versus centrality. Based on predictions from R. Vogt. Excellent agreement with E866 data versus yCM. Parametrizes all the effect that shadowing is missing. T. Frawley ETC, Trento T. Frawley ECT, Trento 9/22/2018 WWND, Jamaica

Extrapolation for HI Corollaries: A. Suppression of excited states assumed to be the same as J/ψ. B. Only folded p+A not necessarily clear that CNM effects factorize in HI collisions Extrapolation when σ(y) allowed (CEM - T. Frawley ) 9/22/2018 WWND, Jamaica

A long d+Au run (with upgrades) to answer this quantitatively! Resolves SPS ε question.(?) 9/22/2018 WWND, Jamaica

More than shadowing? Production Model? Color Glass Initial State? CDF puzzle still not resolved! Color Glass Initial State? Initial State energy loss? 9/22/2018 WWND, Jamaica

Production model? Intrinsic 2 -> 1 RdAu Softens the result Does not completely describe forward suppression (shadowing model dependent) What does this look like for CSM+IC? (arXiv:0908.0754) RdAu Extrinsic 2 -> 2 & model dep. Lansberg et al. arXiv:0912.4498 9/22/2018 WWND, Jamaica

Coherent Multiple Scattering (CGC)? Also calculate the backward rapidity? (anti-shadowing as conservation of momentum) How is this valid for the low energy data at the SPS? “Due to slow energy dependence of Qs” σpA=Aασpp 9/22/2018 WWND, Jamaica

“Guys this is important.” We use 4 centrality bins, each corresponding to a range of impact parameters. Therefore the curve and data on the previous slide are not exactly comparable. One needs to convolute the impact parameter distribution with the theory. This should reduce the amount of suppression. We need to get together and make this plot. “Guys this is important.” -L. McLerran 9/22/2018 WWND, Jamaica

Energy Loss? Data from Drell-Yan at E772 and E866 at Fermilab Energy loss calculated in target rest frame. dE/dx = 2.73  0.37  0.5 GeV/fm (from hadronization) dE/dx ~ 0.2 GeV/fm (from gluon radiation) “This is the first observation of a non-zero energy loss effect in such experiments.” Johnson, Kopeliovich, Potashnikova, E772 et al. Phys. Rev.C 65, 025203 (2002) hep-ph/0105195 Phys. Rev. Lett. 86, 4487 (2001) hep=ex/0010051 9/22/2018 WWND, Jamaica

Why didn’t this catch on? Is this the same as CGC? (CATHIE-INT) Backward shift in xF leads to a slope in rapidity CEM with fixed fractional energy loss. 9/22/2018 WWND, Jamaica

A puzzle Parametrized breakup cross section has a strong kinematic dependence on rapidity. It contains some physics that we have missed with shadowing! Possible Explanations Production Mechanism? “Intrinsic Charm?”– S.Brodsky hep-ph/0904.3037 Gluon Saturation (CGC) ? Tuchin hep-ph/0809.2933 Initial State energy loss? Limiting Fragmentation? Good News: There is more data coming RdAu(y;pT;b) 9/22/2018 WWND, Jamaica

Conclusions Shadowing does not contain all the physics of d+Au collisions. Cold nuclear matter effects predict the rapidity difference in HI collisions (still onset of suppression for central collisions) Experiment: Increase statistics, reduce systematic uncertainties in the measurements. Make more measurements (i.e. χC in d+Au) Theory: Think about the missing physics. 9/22/2018 WWND, Jamaica

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