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Focus talk on interactions between jets and medium

Jörg Ruppert. Nuclear Theory, Duke University. Focus talk on interactions between jets and medium. Outline Energy deposition in the medium, comparison between the mechanisms Mach cones in hydro Probing color response - wakes in a QCD plasma Cherenkov-like gluon bremsstahlung

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Focus talk on interactions between jets and medium

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  1. Jörg Ruppert Nuclear Theory, Duke University Focus talk on interactions between jets and medium Outline • Energy deposition in the medium, comparison between the mechanisms • Mach cones in hydro • Probing color response - wakes in a QCD plasma • Cherenkov-like gluon bremsstahlung • Mach cones in an evolving medium • Conclusion J. Ruppert

  2. f Jet correlations of secondaries Near-side Away-side PHENIX STAR T. Renk, J. Ruppert J. Ruppert

  3. Jet energy loss to the medium • What part of the energy is simply “heating” the plasma,what part is redistributed into excitations of 1) colorless (hydrodynamical) modes => Mach cones J. Casalderray, E. Shuryak, D. Teaney, (2004) hep-ph/0411315, Ulrich Heinz in preparation2) colorful modes: 2.1) longitudinal modes => Mach conesH. Stöcker, Nucl. Phys. A750, (2005) 121, J. Ruppert, B. Müller, Phys. Lett. B618 (2005) 123 2.2) transverse modes =>Cherenkov (like) radiation I. Dremin, JETP Lett.30, (1979) 140 and I. Dremin, hep-ph/0507167, A. Majumder and X.-N. Wang, nucl-th/0507062 • Constraints imposed by momentum conservationBorghini, Eur. Phys. J. C30 (2003), 381-385 • Medium evolution of radiated gluonsS. Pal and S. Pratt, Phys. Lett. B574 (2003), 21-26 J. Ruppert

  4. Mach cones in a hydrodynamical framework? Colorless sound Radiative energy could be deposited in collective hydrodynamical modes. J. Casalderray, E. Shuryak, D. Teaney, (2004) hep-ph/0411315 Idea similar to studies of waves in the nuclear medium which can be excited if supersonically travelling source occurs: See e.g. A. E. Glassgold, W. Heckroth, and KM Watson, Ann. Phys. (Paris) 6, 1 (1959), Scheid et al. Phys.Rev. Lett. 32 (1974), 741 J. Casalderray, E. Shuryak, D. Teaney, (2004) hep-ph/0411315 J. Ruppert

  5. Mach cones from colored sound? [v: parton velocity, u: plasmon propag. velocity] • What is the wake structure induced by a high-pT color charge traversing the QCD medium? • Can Mach waves in the QGP be created? • Information on part of plasma’s properties is contained in longitudinal and transverse components of the dielectric tensor Two scenarios of interest: • High temperature pQCD plasma • Plasma as a quantum liquid H. Stöcker, Nucl. Phys. A750 (2005) 121 J. Ruppert & B. Müller, Phys. Lett. B618 (2005) 123 J. Ruppert

  6. Plasmon branches Longitudinal modes Transverse modes Colored sound Generic result: if a space-like transverse plasmon branch exist Cherenkov-like gluon radiation could be induced.A. Majumder, X.-N. Wang, hep-ph/0507062 Generic result: if a space-like longitudinal plasmon branch exist Mach cone structures could be induced. J. Ruppert & B. Müller, Phys. Lett. B618 (2005) 123 J. Ruppert

  7. 2. Plasma as a quantum liquid: • Subsonic jet: analogous results to pQCD plasma case • Supersonic jet: excitation of longitudinal plasma modes (colored sound) with Mach cone emission angle: Colored wakes in the QCD Medium 1. High temperature pQCD plasma: • Color charge density wake is a co-moving screening cloud: J. Ruppert & B. Müller, Phys. Lett. B618 (2005) 123 J. Ruppert

  8. /T Cherenkov-like gluon bremsstrahlung? Idea of Cherenkov gluon radiation from jets Dremin, JETP Lett.30, (1979) 140 and hep-ph/0507167 Assuming a QGP with space-like transverse plasmon the induced gluon bremsstrahlung via multiple scattering for a superluminally travelling jet can be calculated. A. Majumder, X.-N. Wang, hep-ph/0507062 Predicted angle in the soft-radiation Limit is momentum dependent: ΔΦ=arccos(1/n(p)). Space-like transverse plasmon branches from interaction with bound states(V. Koch, A. Majumder, X.-N. Wang, hep-ph/0507063) J. Ruppert

  9. Fireball evolution model describing hadronic mt spectra, HBT, photon emission and RAA (cf. T. Renk, Phys. Rev. C. 70 (2004) 021903) • Space-time position dependent jet energy deposition into the medium • Fraction fmach of energy deposition into collective mode (sound) • Local speed of sound u (and fireball thermodynamics) from lattice EOS • Propagation of sound waves through evolving medium (incl. flow) • Freeze-out using Cooper-Frye formula • Monte-Carlo sampling using PHENIX trigger conditions and acceptance cuts Mach cones in an evolving medium T. Renk, J. Ruppert J. Ruppert

  10. Mach cone physics at RHIC Propagation through soft point Near side peak Remanents of forward jet momentum Ideal QGP (colorless sound) T. Renk, J. Ruppert J. Ruppert

  11. Conclusion • Mach cones in a quantum liquid plasma are possible! • Calculation of energy deposition into collective sound mode is compatible with data! • Studies of correlations in jet physics teach about the collective phenomena of the nuclear medium created in heavy-ion collision! Be careful: clear 3-particle correlation signals might not necessarily appear in a Mach cone description! J. Ruppert

  12. Mach cone angle J. Ruppert

  13. /T • Majumder, X.-N. Wang, hep- ph/0507062, V. Koch, A. Majumder, X.N. Wang, hep-ph/0507063 STAR PHENIX pTtrig=4-6 GeV/c pTassoc=0.15-4 GeV/c J. Ruppert

  14. Color Octet vs. color Singlet Colored sound J. Ruppert

  15. Making colorful wakes Hard scattered parton (=jet-precursor) acts as a point-like probe current: In a simplified model description one disregards changes of the incident color charges. Thoma, Gyulassy, Nucl.Phys. B351:491 (1990), Weldon, Phys. Rev. D26, 1394 (1983) Induced charge- and current densities: J. Ruppert

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