f meson production in AuAu collisions at RHIC

f meson production in Au+Au collisions at RHIC - Current status and outlook - Tatsuya Chujo (BNL) for the PHENIX Collaboration Tatsuya CHUJO/ BNL Hawaii 2001, DNP/JPS meeting 10/20/2001

f meson physics @ RHIC • In dense and hot matter, the modification of properties of vector meson (e. g. mass shift, branching ratio) is predicted, due to the partial chiral symmetry restoration. (T. Hatsuda et al. PRC 46 (1992) R 42, E. G. Drukarev et al. , Nucl. Phys. 27 (1991) 77) • In Au+Au at RHIC energy, 1. 2. 3. if it’s changed Invariant mass distribution Simultaneous measurements of different decay channel (f K+K, e+e-) Centrality dependence of yields and p. T distribution Possible signature of QGP Constraint of freeze-out condition Tatsuya CHUJO/ BNL Hawaii 2001, DNP/JPS meeting 10/20/2001

PHENIX acceptance for f K+K- @ TOF f K+ K • TOF Acceptance Dq = 40 deg. (Dh = 0. 7) , Df = 45 deg. TOF was designed to cover f meson acceptance and HBT measurement Tatsuya CHUJO/ BNL Hawaii 2001, DNP/JPS meeting 10/20/2001

PHENIX-TOF 96 slats/panel Plastic Scintillator 385 cm 10 panels 200 cm PMT 200 cm • • Consists of 960 plastic scintillators PMT readout at both ends of scint. (1920 ch. ) Enough granularity to reduce the double hit probability in the same slat (Occupancy < 10%) Tatsuya CHUJO/ BNL Hawaii 2001, DNP/JPS meeting 10/20/2001

TOF Resolution Update • Overall Time-of-Flight resolution s TOF < 96 ps (@ Oct. 2001) • Flight path length : ~ 5 m • K/p separation : < ~2 Ge. V/c • p/K separation : < ~4 Ge. V/c Achieved timing resolution of less than 96 ps! (improvement of slewing correction and run dependent timing offset. ) Tatsuya CHUJO/ BNL Hawaii 2001, DNP/JPS meeting 10/20/2001

Mass Squared Distribution m 2 vs. momentum Mass squared distribution 2. 0 < p < 2. 2 Ge. V/c p K p p/K separation up to ~2. 2 Ge. V/c Introduced 3 s cut in (m 2 – m 0) for Kaon PID Tatsuya CHUJO/ BNL Hawaii 2001, DNP/JPS meeting 10/20/2001

Single Particle Simulation (f K+K-) • MC simulation of single f meson including PHENIX detector response. • Forced to decay to K+K- channel. • Exponential + flat Pt distribution for f meson. • Invariant mass Reconstructed (K+K-) f simulation Generated f Invariant mass [Ge. V/c 2] * Momentum cut off 0. 2 < p < 2. 0 Ge. V/c Tatsuya CHUJO/ BNL Hawaii 2001, DNP/JPS meeting 10/20/2001

Invariant Mass (f K+K-) from Year-1 Data (a. u. ) Invariant mass (K+K-) in TOF Acceptance Au+Au @ , Minimum bias Difficulties due to. . • Statistical limitation • Limited Acceptance • Drift Chamber inefficiency in year-1 data in TOF acceptance Improvement in Year-2 data! rk o W ss e r rog p in f (1020) ? Tatsuya CHUJO/ BNL Hawaii 2001, DNP/JPS meeting 10/20/2001

Outlook of Run 2001 data l l l Expected the drastic improvement of f statistics in this year’s data. (integrated luminosity in Au+Au will be 300 mb-1 Au+Au) Full central arm acceptance using the EMC (Pb. Sc, Pb. Gl) in this year. Good Dch efficiency in TOF acceptance in this year. f K+ K- Physics: 1. 2. Centrality dependence of yield and pt distribution of f at RHIC full energy. Measurements of branching ratio using the full central arm acceptance (EMC-RHIC). N(f K+K-)/N(f e+e-) Event reconstruction is now in progress Tatsuya CHUJO/ BNL Hawaii 2001, DNP/JPS meeting 10/20/2001