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Experiment Summary. Craig Ogilvie Iowa State University, cogilvie@iastate.edu. Highlights of new results shown at this meeting Experimental consistency between experiments baryons, anti-baryons Top 10 “Baryon” results I’m excited to see at QM2002 (and beyond).
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Experiment Summary Craig Ogilvie Iowa State University, cogilvie@iastate.edu • Highlights of new results shown at this meeting • Experimental consistency between experiments • baryons, anti-baryons • Top 10 “Baryon” results I’m excited to see at QM2002 (and beyond)
Ratios @ 200 AGeV (I): BRAHMS Craig Ogilvie
200 GeV Ratios from PHOBOS Craig Ogilvie
pp ->pbar and pn->Pbar 158 GeV Craig Ogilvie
pAu => L, 18 GeV/c E910 Phys.Rev.Lett. 85 (2000) 4868 Increase in L with n reproduces much of A+A strangeness Craig Ogilvie
Rapidity Loss AGS Craig Ogilvie
Baryons, Experiment Consistency (I) Craig Ogilvie
Message • Experimental results are consistent with each other • STAR’s improved dN/dy analysis (more constraint on shape) • well within the systematic errors quoted by their papers Craig Ogilvie
Baryons, Experiment Consistency (II) Craig Ogilvie
Top 10 “Baryon” Results I’m Looking Forward toAt QM and Beyond
10: Systematics • p+p @ 200 GeV => hadron spectra and yields • p+-, K+-, p, p, L, L, n • provides expt. foundation for all our physics • d+Au Run III RHIC • provides p+Au and n+Au mixed • challenge to measure Ngrey • Ngrey => np + nn additional smearing, Craig Ogilvie
9: Degree of Strangeness Saturation: • Yield of multi-strange baryons in Au+Au 200 AGeV • If strangeness fully equilibrated => gs = 1 F. Becattini hep-ph 0202071 What is gs at RHIC? If gs larger than SPS, suggests rescattering: QGP or in hadron gas? Craig Ogilvie
Cascade/pion from STAR Craig Ogilvie
8: Nice to Get Some Understanding of L/pdirect Central, Au+Au and Pb+Pb pdirect corrected for feed-down E917 Phys.Rev.Lett. 87:242301,2001 L WA97 Phys. Lett B 449, 401 (1999) p NA49 Nucl. Phys A661 383 (1999) L/pdirect ~ 1 at RHIC !! L/p ~ 0.2-0.3 pp Craig Ogilvie
7: Charmed Baryons Baryon-junction models => enhanced mid-rapidity L and p could also lead to enhanced Lc ? Lc+ => pK-p+ B.R. 5%, ct ~ 60mm combinatorial background large, vertex detector upgrades? Lc+ => Lp+ B.R. 0.009%, HIJING min-bias estimate 1 Lc per 300 events Craig Ogilvie
PHENIX Au+Au 130 GeV Open symbols pp reactionsnucl-ex/0112006 6: Accurate <pt> in Near-Peripheral Collisions • Measure <pt> from pp, dA • baseline, multiple collisions • 2) Measure <pt> Au+Au Npart < 50 • 3) Si+Si to control Npart • multiple collisions ? • onset of expansion ? • pt kick from junction ? Craig Ogilvie
5: p/p vs pt measure p / p and K/ p Au+Au and baseline pp @ 200 GeV - does p / p in Au+Au continue to rise at high-pt (hydro) ? - or fall at high-pt (fragmentation models) ? PHENIX prelim Au+Au 130 GeV Craig Ogilvie
Au+Au 130 AGeV PHENIX prelim 1.4 1.2 1 0.8 0.6 0.4 0.2 1 2 3 pt (GeV/c) 4: p / p at High-pt In p+p, ratio decreases, fragmentation q => p dominate g => p a) measure p / p with Au+Au, pp @ 200 GeV b) energy-loss predicts stronger decrease in p / p Wang Phys.Rev. C58 (1998) 2321 pt (GeV/c) Craig Ogilvie
3: Balance Function For Baryons given p, what is cond. probability of finding proton at Dy? and inverse questions, with a subtraction of combinatorics • Thermal + long. expansion • late hadronization • protons anti-protons tightly correlated in rapidity Craig Ogilvie
2: Rapidity Distribution of p-p Strive for p - p over broad range of rapidity - p+p, d+Au and Au+Au - discriminate between models Currently p/p available Au+Au central 130 AGeV BRAHMS Phys.Rev.Lett. 87 (2001) 112305 Craig Ogilvie
1: L-L and pdirect-pdirect Au+Au central 5% 130 AGeV HIJING/B describes both L -L and pdirect -pdirect But not L yield ( factor two underpredict, Vasile Pop Mar’02) STAR’s (L -L = 5.0 0.2 0.5) eliminates HIJING L and L yieldschallenge to models Craig Ogilvie