1 / 21

Heavy Flavor Flow

Heavy Flavor Flow. Che-Ming Ko Texas A&M University. Light hadron flows at RHIC Charm flow at RHIC Charm and beauty flow at LHC Summary. Collaborator: Lie-Wen Chen (Shanghai), Vincenzo Greco, Ralf Rapp, Bin Zhang (Arkansas). (. ). T. ¹.

ursula
Download Presentation

Heavy Flavor Flow

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Heavy Flavor Flow Che-Ming Ko Texas A&M University • Light hadron flows at RHIC • Charm flow at RHIC • Charm and beauty flow at LHC • Summary Collaborator: Lie-Wen Chen (Shanghai), Vincenzo Greco, Ralf Rapp, Bin Zhang (Arkansas)

  2. ( ) T ¹ º ¹ º ¹ º + ¡ e p u u p g = ¹ º @ T 0 = ¹ ¹ @ 0 n = i ¹ Elliptic flow from hydrodynamic model Heinz & Kolb; Teaney & Shuryak; Hirano e: energy density p: pressure uμ: four velocity With an initial energy density of ~25 GeV/fm3, hydro describes very well data at low pT (mass effect) but fails at intermediate pT.

  3. Elliptic flow from AMPT Lin & Ko, PRC 65, 034904 (2002) • Using αs=0.5 and screening mass • μ=gT≈0.6 GeV at T≈0.25 GeV, then • <s>1/2≈4.2T≈1 GeV, and pQCD gives • σ≈2.5 mb and a transport cross section • σ=6 mb → μ≈0.44 GeV, σt≈2.7 mb • σ=10 mb → μ≈0.35 GeV, σt≈3.6 mb Need string melting and large parton scattering cross section.

  4. Elliptic flow from quark coalescence/recombination Greco, Levai & Ko, PRC 68, 034904 (2003) Fries, Meuller, Nonaka & Bass, PRC 68, 044902 (2003) With Δp=0.24 GeV for mesons and 0.36 GeV for baryons

  5. Naïve quark coalescence model and constituent quark numer scaling of hadron elliptic flows Only quarks of same momentum can coalescence, i.e., Δp=0 Quark transverse momentum distribution Meson elliptic flow Quark number scaling of hadron v2 (except pions): Baryon elliptic flow same for mesons and baryons

  6. Effects due to momentum dispersion and resonance decays Effect of resonance decays Momentum dispersion effect Mom. Disp + res. decays

  7. Higher-order anisotropic flows Data can be described by a multiphase transport (AMPT) model. Parton cascade Data

  8. S. Kelly,QM04 Charm elliptic flow at RHIC Smaller charm v2 than light quark V2 at low pT due to mass effect V2 of electrons Data consistent with thermalized charm quark with same v2 as light quarks. Greco, Rapp & Ko, PLB595, 202 (04)

  9. Quark elliptic flows from AMPT • Compared to v2 of light quarks, charm quark v2 is smaller at low • pT due to its large mass but becomes comparable at high pT. • Charm quark v2 is also sensitive to it scattering cross section.

  10. Charm transverse momentum spectra from AMPT

  11. Charmed meson elliptic flow from AMPT Zhang, Chen & Ko, nucl-th/0502056 Current light quark masses are used in AMPT. Charmed meson elliptic flow will be larger if constituent quark masses are used.

  12. Elliptic flow from Molnar’s Parton Cascade Molnar, JPG 31, S421 (2005) Results were obtained with constituent quark masses and σgg→gg≈(9/4)σqg→qg≈(9/4)2σqq→qq=10 mb, which is about 4 times those from pQCD.

  13. Charm elliptic flow from the Langevin model Moore & Teaney, hep-ph/0412346 Light hadron v2 from STAR a=1.5 Momentum drag coefficient a=3 Spatial diffusion coefficient a=6 mean squared momentum transfer per unit time, proportional to σ a=12 pQCD gives D≈a/(2πT) in QGP with a=6 a=24

  14. Charm flow from HSD (Hadron-String-Dynamics) transport model Bratkovskaya, Cassing, Stoecker & Xu, PRC 71, 044901 (2005) Hadronic scattering in HSD gives a smaller elliptic flow than that from partonic scattering in AMPT and MPC.

  15. Hadron rapidity distributions at LHC from AMPT Pb+Pb @ 5.5 TeV Charged particle multiplicity is about a factor of two larger than at RHIC.

  16. Hadron transverse momentum spectra at LHC Larger inverse slope parameters due to larger radial flow at LHC.

  17. Quark elliptic flow at LHC Quark elliptic flow is about twice that at RHIC.

  18. Heavy flavor 4th-order anisotropic flow

  19. Summary • Heavy flavor flow is sensitive to its scattering cross section or diffusion coefficient in QGP. • Existing data at RHIC are consistent with a large scattering cross section. • Heavy flavor flows are expected to be even larger at LHC than at RHIC. • Heavy flavor v4 non-negligible and v4~1.1(v2)2. • What is the origin of large charm scattering cross section? • How does charm elliptic flow depend on system size?

  20. Resonance effect on charm scattering in QGP Van Hees & Rapp, PRC 71, 034907 (2005) With mc≈1.5 GeV, mq≈5-10 MeV, mD≈2 GeV, ΓD≈0.3-0.5 GeV, and including scalar, pseudoscalar, vector, and axial vector D mesons gives σcq→cq(s1/2=mD)≈6 mb Since the cross section is isotropic, the transport cross section is 6 mb, which is about 4 times larger than that due to pQCD t-channel diagrams.

  21. System size dependence of elliptic flow

More Related