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Resonance production in jets

Resonance production in jets. Christina Markert University of Texas at Austin. Motivation Resonance measurements Time evolution of hadronic phase Chiral symmetry restoration Resonances from jets Summary and a lot of future plans. T chemical. T chemical.

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Resonance production in jets

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  1. Resonance production in jets Christina Markert University of Texas at Austin • Motivation • Resonance measurements • Time evolution of hadronic phase • Chiral symmetry restoration • Resonances from jets • Summary and a lot of future plans Christina Markert23rd WWND Montana, Big Sky, Feb 12-17

  2. Tchemical Tchemical Lifetime of nuclear medium Dt ~ > 4 fm/c resonances t ~ 10 fm/c 2 particle correlation Partonic phase  < 6 fm/c Christina Markert23rd WWND Montana, Big Sky, Feb 12-17

  3. K f signal measured late decay p K p K* K rescattering signal lost p K* p kinetic freeze-out signal measured chemical freeze-out K K regeneration e+ signal measured early decay r e- p+ signal measured late decay r p- p r e+ signal measured late decay p e- time Hadronic re-scattering and regeneration Life-time [fm/c] : r = 1.3 ++ = 1.7 K(892) = 4.0 S(1385) = 5.7 L(1520) = 13  (1020) = 45 • Depends on: • hadronic phase density • hadronic phase lifetime Christina Markert23rd WWND Montana, Big Sky, Feb 12-17

  4. Resonance suppression in central collisions Phys. Rev. Lett. 97 (2006) 132301e-Print Archive: nucl-ex/0604019 Resonances from late decay Christina Markert23rd WWND Montana, Big Sky, Feb 12-17

  5. Resonance decay product re-scattering Decay daughters from low pT resonances re-scatter in hadronic phase Decay daughters from high pT resonances are less affected by hadronic phase Net shift in <pT> • Resonance signal from early medium • Leptonic decay • High momentum resonance Christina Markert23rd WWND Montana, Big Sky, Feb 12-17

  6. Resonance response to medium Temperature LHC? Shuryak QM04 Quark Gluon Plasma partons Resonances below and above Tc: • Chiral symmetry restoration Mass and width of resonances • Hadronic time evolution From hadronization (chemical freeze-out) to kinetic freeze-out. Tc T Freeze hadrons Hadron Gas Baryochemical potential Christina Markert23rd WWND Montana, Big Sky, Feb 12-17

  7. Chiral symmetry restoration Vacuum At Tc: Chiral Restoration Data: ALEPH Collaboration R. Barate et al. Eur. Phys. J. C4 409 (1998) Measure chiral partners near critical temperature Tc (e.g. r and a1) a1p + g Ralf Rapp (Texas A&M) J.Phys. G31 (2005) S217-S230 Christina Markert23rd WWND Montana, Big Sky, Feb 12-17

  8. |1/β-1|<0.03 Leptonic resonance reconstruction Electronics and detector assembling at UT Austin STAR Experiment J.WU QM2006 STAR: Electron hadron separation with Time of Flight upgrade detector Christina Markert23rd WWND Montana, Big Sky, Feb 12-17

  9. Resonance in a medium (nuclear matter) Mass shift and width broadenings are predicted as influence of medium on resonance spectral function, e.g.: For baryonic and strange resonances M.F.M Lutz (SQM 2001) J.Phys.G28:1729-1736,2002 M.F.M Lutz, E.E. Kolomeitsev, Nucl.Phys.A755:29-39,2005. hep-ph/0501224 For mesonic resonances Ralf Rapp (Texas A&M) J.Phys. G31 (2005) S217-S230 L(1520) andS(1385) resonances decay channel change M. Kaskulov et al., nucl-th/0509088 Christina Markert23rd WWND Montana, Big Sky, Feb 12-17

  10. Resonance in a medium (nuclear matter) Spectral function of L states M.F.M Lutz J.Phys.G28:1729-1736,2002 (1520) and S(1385) in medium r= 1r0 (1520): ~100 MeV mass shift and (100 MeV width) S(1385): ~40 MeV mass shift and (50 MeV width) Christina Markert23rd WWND Montana, Big Sky, Feb 12-17

  11. near away T=170 MeV, bT=0 Leading hadrons Medium Resonances from jets to probe chirality L* jets ?  L* Bourquin and Gaillard Nucl. Phys. B114 (1976) • In p+p collisions resonances are predominantly • formed in jets. • Comparison of resonances from jets (no medium) • with resonances from bulk (medium) Christina Markert23rd WWND Montana, Big Sky, Feb 12-17

  12. away near STAR Preliminary Resonances from jets In jet –plane Df = 0 In jet-plane Out of jet-plane Df = p Df = p/2 Study Chiral Symmetry Restoration by comparing resonance production in event classes based on azimuthal distribution: We expect high pT resonances from the away side jet to be medium modified due to the high density and temperature of the partonic and early hadronic medium Christina Markert23rd WWND Montana, Big Sky, Feb 12-17

  13. side 1 near away side 2 Resonances from jets and formation time K. Gallmeister, T. Falter. Phys.Lett.B630:40-48,2005 General pQCD: Formation time [fm/c] ~ pT [GeV] Specific string fragmentation (PYTHIA) formalism: Gallmeister, Falter, PLB630, 40 (2005) Heavier particles form later, Resonances form earlier Which are the right momenta for trigger and resonance particle? Christina Markert23rd WWND Montana, Big Sky, Feb 12-17

  14. First attempt: f(1020) reconstruction in STAR Trigger/Event Number of triggers M inv (K+ K-) • 4.5 M Au+Au 0-20% most central data • Leading hadron particle pT > 4.0 •  trigger/event = 0.12 • Associated resonance particle f(1020) •  <pT>~ 0.9 GeV • f(1020)/event = 0.05 M inv (K+ K-) Christina Markert23rd WWND Montana, Big Sky, Feb 12-17

  15. side 1 near away side 2 f(1020) from same/away side in/out of plane Trigger pT > 4GeV, f(1020) <pT>~ 0.9 GeV All angles In Jet-Plane Same Sidenear M inv (K+ K-) M inv (K+ K-) Out of Jet-Planeside1 + side2 In Jet-Plane Away Sideaway Systematic errors not included ! M inv (K+ K-) M inv (K+ K-) No mass shifts or width broadenings visible  Expected, since pT of f(1020) is small, need to increase f pT Less signal at the same side compared to away side (20%±10%) Christina Markert23rd WWND Montana, Big Sky, Feb 12-17

  16. Hadron - resonance correlation in Au+Au Df of h-f(1020) – C • h-f(1020) mixed event Hadron trigger pT > 4 GeV f(1020) <pT > ~ 0.9 GeV ( need higher pt ) Not corrected for acceptance Systematic BG normalization error not included STAR preliminary ZYAM = zero yield at minimum Pythia 75M events p+p 200 GeV only phi (no background from K+K combinations) Pythia p+p QM2006 M.Horner See Jana’s and Betty’s talk Christina Markert23rd WWND Montana, Big Sky, Feb 12-17

  17. Conclusion and future plans • Hadronic low momentum resonances are affected by hadronic • interaction medium Measurement provides lifetime between chemical and thermal freeze out • High momentum resonances from jets might be used as a tool to • trigger on early produced resonances and test chiral symmetry • restoration if they leave the hadronic medium without interaction • Need theoretical description of resonance momentum • and medium density when decay occur. • Study p+p and Au+Au data with different pT selections for • associated and trigger resonances in hadron-resonance • correlations. • Reconstruct resonances in jets with shorter lifetime as • f(1020) but sufficient statistics (e.g. K*, D) Christina Markert23rd WWND Montana, Big Sky, Feb 12-17

  18. EMCal in ALICE • Without single jet reconstruction only statistical • Analysis possible. • Jet reconstruction Calorimeter necessary • Major advantages at the LHC: • Jet energy known, i.e. measure effect as function of fractional momentum • Enhanced statistics in relevant resonance pt-Range (3-10 GeV/c) • Trigger on quark and gluon jets separately Christina Markert23rd WWND Montana, Big Sky, Feb 12-17

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