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PPG067 Physics Statements Michael P. McCumber and Barbara Jacak August + September, 2006
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25 September 2006Michael P. McCumber & Barbara Jacak 2 Figure 3 rms increases with npart kurtosis decreases rapidly from near- gaussian values away side peak dispacement is consistent with 0 in dAu & peripheral AuAu. rapidly increases to about 1 rad.
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25 September 2006Michael P. McCumber & Barbara Jacak 3 Mechanisms for away-side modification Mach Cone Cherenkov Gluon-Radiation Wake Waves Medium-induced gluon radiation at large emission angles Damping of jet by strongly coupled medium (via AdS/CFT)
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25 September 2006Michael P. McCumber & Barbara Jacak 4 Mach Cones – Renk & Ruppert hep-ph/0605330 Mach cone survives expansion! Longitudinal flow → better Δφ signal from a Mach Cone Data → large fractional of energy deposited in collective, propagating mode AwayNear→
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25 September 2006Michael P. McCumber & Barbara Jacak 5 Mach Cones – Chaudhuri & Heinz hydro simulations: assume lost energy instantaneously thermalized No Mach cone produced Large energy loss scenarios give “splash-back” signal rejected by data PRL97, 062301 (2006)
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25 September 2006Michael P. McCumber & Barbara Jacak 6 Mach Cones – Jorge & Edward Modified away side peak shape is due to propagation of a sound wave Speed of sound intermediate between QGP (c s = 0.33) and hadron gas (c s = 0.2) First order phase transition causes existence of region with c s =0. This would give a reflected wave, and 2 nd peak at =1.4 rad NP A774, 577 (2006) & hep-ph/0511263
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25 September 2006Michael P. McCumber & Barbara Jacak 7 Mach Cones – Jorge & Edward hep-ph/0511263 No clear (or even unclear) evidence for second peak in ppg032 result
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25 September 2006Michael P. McCumber & Barbara Jacak 8 Run 4 AuAu not here either… (maybe in 0-5% bin?)
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25 September 2006Michael P. McCumber & Barbara Jacak 9 Cherenkov – Koch, Majumder, Wang Cherenkov production has “a strong dependence on the gluon momentum” & will “disappear for high-energy gluons” D values will “gradually” shrink as associated momentum is increased. Not consistent with our data PRL 96,172302 (2006) Paul C’s AN
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25 September 2006Michael P. McCumber & Barbara Jacak 10 Wake Waves – Ruppert, Muller Excite either a density wave or a plasma collective mode (plasmon) Sub-sonic partons drag along a screening cloud as a wake (the response of plasma to color charge) Super-sonic partons create Mach cone signal If plasma is strongly coupled, high p parton excites plasma oscillations analogous to Cherenkov radiation (but it looks like Mach cone…) PL B618, 123 (2005)
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25 September 2006Michael P. McCumber & Barbara Jacak 11 Large angle gluon emission -- Vitev PL B630, 178 (2005) Predicted angles are typically smaller than observed. p T dependence in central collisions (like the data) Average scattering angle decreases with path length This contrasts our centrality dependence!
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25 September 2006Michael P. McCumber & Barbara Jacak 12 large angle gluon emission #2 Polosa & Salgado hep-ph/0607295 Look at symmetric & asymmetric gluon splittings (asym ~ like Vitev) p T trigger ~ p T associated restrict signal to a small number of splittings Smaller qhat & larger radiated – gluons more collinear. So effects should disappear at smaller pTassoc at 62 than 200 GeV. can we say anything about this? Vitev does opacity expansion, they use BDMPS
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25 September 2006Michael P. McCumber & Barbara Jacak 13 AdS/CFT correspondence of gravity in 5D string theory & field theory similar (but not identical) to QCD → field properties in limit of super strong coupling. Friess, et al. (hep-th/0607022) stress tensor →wake of directional emission at p = several times the temperature see also Casalderry &Teaney (nucl-th/0605199) Liu, Rajagopal, Wiedemann (hep-ph/0607062) on qhat
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25 September 2006Michael P. McCumber & Barbara Jacak 14 Figure 3 universal curve with N part ! data imply: away side jet splitting is a property of the medium, rather than the specific collision system successful models include strong medium response to jet
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