fMeson Production in d Au and Au Au

f-Meson Production in d – Au and Au – Au Collisions at √s. NN = 200 Ge. V Dipali Pal Vanderbilt University (for the PHENIX Collaboration) Fall DNP 2004, Chicago 1

Outline • Motivation § PHENIX experiment § f mesons in d-Au collisions • Line shape analysis • Yield analysis – Centrality dependence – Comparison with Au – Au results (for Au – Au f K+K- reults, see the presentation JB 9 by D. S. Mukhopadhyay) • Summary and outlook Fall DNP 2004, Chicago 2

Physics motivation f mesons • Chiral symmetry restoration and medium effects - mass shift, width broadening Line shape analysis • Strangeness production - f meson yield and centrality dependence • Au – Au & d – Au collisions – Distinguish between hot and cold partonic matter – Evolution of medium properties with density and temperature – Probing nuclear effects Fall DNP 2004, Chicago 3

PHENIX Setup K+ K- KK+K- Collision vertex and centrality: Beam-beam Counter Tracking : DC – PC 1 – PC 3 Momentum K+ Kf K+KKaon identification: TOF: |Dh| < 0. 35, Df = 45 o Pb. Sc (East): |Dh| < 0. 35, Df = 45 o Pb. Sc (West): |Dh| < 0. 35, |Df| = 90 o Fall DNP 2004, Chicago 4

Line shape analysis d – Au collisions at √s. NN = 200 Ge. V f K+K- Minimum bias events Nevt = 54 M Fitting function: Breit Wigner convolved with Gaussian Mass resolution function of s ~ 1. 4 Me. V/c 2 <m> = 1. 01911 ± 0. 00016 ± 0. 00085 Ge. V/c 2 (stat) (syst) G = 4. 567± 0. 441 (stat)± 0. 313 (syst) Me. V/c 2 S = 786 ± 34, S/B = 1/0. 47 Work-in-progress Minimum bias centroid and width is consistent with PDG values: <m>PDG = 1. 019456 Ge. V/c 2 G = 4. 26 Me. V/c 2 Study the centrality dependence of line shape. Fall DNP 2004, Chicago 5

Centrality dependence of Line shape Systematic error band PHENIX Preliminary Systematic error PHENIX Preliminary f meson’s line shape in cold nuclear matter: è Centroids are consistent with PDG at all centralities è Widths are consistent with PDG within less than 2 s Fall DNP 2004, Chicago 6

m. T spectrum (Minimum bias) • Yield of f in each m. T bin is corrected with acceptance and reconstruction efficiencies by PHENIX MC simulation. • The corrected spectra is fitted with m. T exponential function with d. N/dy and T as two fitting function. • Preliminary d. N/dy and T of f in K+K- and e+e- decay channels are consistent with each other. (See the presentation by D. Kotchetkov, JB 003 for the status of f e+e- analysis) Systematic error Work-in-progress Fall DNP 2004, Chicago 7

m. T spectrum (centrality selected) Systematic error PHENIX Preliminary d. N/dy = 0. 016 ± 0. 003 (stat) ± 0. 003 (syst) T = 313 ± 32(Stat) ± 22 (Syst) Me. V Systematic error PHENIX Preliminary Fall DNP 2004, Chicago 8

Centrality dependence: Yield Au-Au @ √s. NN=200 Ge. V (PHENIX Final) è d. N/dy increases with centrality and from d-Au to Au-Au system. è d. N/dy per participant pair is flat for d-Au system within errors, but increases from d-Au to Au – Au system. Fall DNP 2004, Chicago 9

Centrality dependence: Inverse slope Au – Au @ √s. NN = 200 Ge. V (PHENIX Final) è The inverse slope is almost constant within different centrality classes of d-Au and is consistent with Au-Au system. Fall DNP 2004, Chicago 10

Summary and outlook § f mesons are measured in d-Au and Au-Au collisions. • Preliminary results on f meson line shape study in d-Au collisions shows consistency with PDG values. • m. T spectra, d. N/dy and T is measured at five centrality classes. Preliminary results show that both d. N/dy and T are independent of centrality within errors. • Increase in d. N/dy from d-Au (Preliminary) to Au-Au (Final) while the temperature remains almost constant within errors. Fall DNP 2004, Chicago 11