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Essential Measurements to be made at RHIC using the PHOBOS Detector

Essential Measurements to be made at RHIC using the PHOBOS Detector. Mark D. Baker Brookhaven National Laboratory for the PHOBOS Experiment. BNL 08-SEP-2004 Physics Advisory Committee Meeting. Collaboration (Oct. 2004).

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Essential Measurements to be made at RHIC using the PHOBOS Detector

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  1. Essential Measurements to be made at RHIC using the PHOBOS Detector Mark D. Baker Brookhaven National Laboratory for the PHOBOS Experiment BNL 08-SEP-2004 Physics Advisory Committee Meeting

  2. Collaboration (Oct. 2004) Birger Back,Mark Baker, Maarten Ballintijn, Donald Barton, Russell Betts, Abigail Bickley, Richard Bindel, Wit Busza (Spokesperson), Alan Carroll, Zhengwei Chai, Patrick Decowski, Edmundo García, Tomasz Gburek, Nigel George, Kristjan Gulbrandsen, Clive Halliwell, Joshua Hamblen, Adam Harrington, Michael Hauer, Conor Henderson, David Hofman, Richard Hollis, Roman Hołyński, Burt Holzman, Aneta Iordanova, Jay Kane, Nazim Khan, Piotr Kulinich, Chia Ming Kuo, Willis Lin, Steven Manly, Alice Mignerey, Gerrit van Nieuwenhuizen, Rachid Nouicer, Andrzej Olszewski, Robert Pak, Inkyu Park, Heinz Pernegger, Corey Reed, Christof Roland, Gunther Roland, Joe Sagerer, Helen Seals, Iouri Sedykh, Wojtek Skulski, Chadd Smith, Maciej Stankiewicz, Peter Steinberg, George Stephans, Andrei Sukhanov, Marguerite Belt Tonjes, Adam Trzupek, Carla Vale, Sergei Vaurynovich, Robin Verdier, Gábor Veres, Peter Walters, Edward Wenger, Frank Wolfs, Barbara Wosiek, Krzysztof Woźniak, Alan Wuosmaa, Bolek Wysłouch ARGONNE NATIONAL LABORATORY BROOKHAVEN NATIONAL LABORATORY INSTITUTE OF NUCLEAR PHYSICS PAN, KRAKOW MASSACHUSETTS INSTITUTE OF TECHNOLOGY NATIONAL CENTRAL UNIVERSITY, TAIWAN UNIVERSITY OF ILLINOIS AT CHICAGO UNIVERSITY OF MARYLAND UNIVERSITY OF ROCHESTER Mark D. Baker

  3. The PHOBOS Detector (2004) • 4-p Multiplicity Detector • Comprehensive centrality measures • Magnetic Spectrometer + ToF • Extends to very low pT • Good rejection of weak decays T0 counter SpecTrig TOF Paddle Trigger Counter Octagon Spectrometer NIM A 499 (2003) 603 Mark D. Baker

  4. Physics Publications (Sept. 2003) Phys. Rev. Lett. 85 , 3100 (2000) Phys. Rev. Lett. 87, 102301 (2001) Phys. Rev. Lett. 87, 102303 (2001) Phys. Rev. C 65 , 31901R (2002) Phys. Rev. Lett. 88 , 22302 (2002) Phys. Rev. C 65 , 061901R (2002) Phys. Rev. Lett. 89 , 222301 (2002) Phys. Rev. C 67, 021901R (2003) Phys. Rev. Lett. 91, 052303 (2003) nucl-ex/0301017, subm. to PRL nucl-ex/0302015, subm. to PLB Phys. Rev. Lett. 91, 072302 (2003) nucl-ex/0309013, subm. to PRC-RC & Comparable # in the pipeline! Mark D. Baker

  5. Physics Publications (Sept. 2004) Phys. Rev. Lett. 85 , 3100 (2000) Phys. Rev. Lett. 87, 102301 (2001) Phys. Rev. Lett. 87, 102303 (2001) Phys. Rev. C 65 , 31901R (2002) Phys. Rev. Lett. 88 , 22302 (2002)  Phys. Rev. C 65 , 061901R (2002) Phys. Rev. Lett. 89 , 222301 (2002) Phys. Rev. C 67, 021901R (2003) Phys. Rev. Lett. 91, 052303 (2003) nucl-ex/0301017, subm. to PRL Phys. Lett. B 578, 072302 (2003) Phys. Rev. Lett. 91, 072302 (2003) Phys. Rev. C 70, 011901R (2004) Phys. Rev. Lett. 93, 082301 (2004) dN/dh for dAu nucl-ex/0401006, subm. to PRL PID at very low pT nucl-ex/0405003, subm. to PRL Energy dependence of R(AA) Phys. Rev. C 70, 021902R (2004) Geometric dN/dh scaling nucl-ex/0406017, subm. to PRC-RC R(dAu) vs. h nucl-ex/0406021, subm. to PRL v2 vs. h’ at 4 energies nucl-ex/0407012, subm. to PRC-RCv2 vs. h, centrality, pT nucl-ex/0409001, subm. to PRC-RCHBT vs pT, y at 62.4, 200 nucl-ex/0409003, subm. to PRC-RCpbar/p for pp >700 citations total ~20 more in pipeline! Mark D. Baker

  6. Physics Publications (Sept. 2004) Phys. Rev. Lett. 85 , 3100 (2000) Phys. Rev. Lett. 87, 102301 (2001) Phys. Rev. Lett. 87, 102303 (2001) Phys. Rev. C 65 , 31901R (2002) Phys. Rev. Lett. 88 , 22302 (2002)  Phys. Rev. C 65 , 061901R (2002) Phys. Rev. Lett. 89 , 222301 (2002) Phys. Rev. C 67, 021901R (2003) Phys. Rev. Lett. 91, 052303 (2003) nucl-ex/0301017, subm. to PRL Phys. Lett. B 578, 072302 (2003) Phys. Rev. Lett. 91, 072302 (2003) Phys. Rev. C 70, 011901R (2004) Phys. Rev. Lett. 93, 082301 (2004) dN/dh for dAu nucl-ex/0401006, subm. to PRL PID at very low pT nucl-ex/0405003, subm. to PRL Energy dependence of R(AA) Phys. Rev. C 70, 021902R (2004) Geometric dN/dh scaling nucl-ex/0406017, subm. to PRC-RC R(dAu) vs. h nucl-ex/0406021, subm. to PRL v2 vs. h’ at 4 energies nucl-ex/0407012, subm. to PRC-RCv2 vs. h, centrality, pT nucl-ex/0409001, subm. to PRC-RCHBT vs pT, y at 62.4, 200 nucl-ex/0409003, subm. to PRC-RCpbar/p for pp * AuAu energies: 19.6, 55.9, 62.4 130., 200. >700 citations total * * * (1st Run IV paper) * * (2nd Run IV paper) * (3rd Run IV paper) * ~20 more in pipeline! Mark D. Baker

  7. PRL 91 (2003) 072302-5 Results from dAu - an update RdA(h,pT)? dN/dh data from nucl-ex/0403033 J.Phys.G30 (2004) S1133 Mark D. Baker

  8. Results from dAu - an update RdA(h,pT)! dN/dh data from nucl-ex/0403033 J.Phys.G30 (2004) S1133 nucl-ex/0406017 Mark D. Baker

  9. Varying the beam energy changes: • Initial state: sNN, Ncoll/Npart, Qs(?) • System: , mB, Nch • Partonic: xT, dE/dx The program: vary energy and geometry Varying the geometry (A,b): • jet quenching • vary overall path length • vary asymmetry • Elliptic (and directed) flow • Study A dependence at fixed eccentricity. Npart Mark D. Baker eccentricity

  10. Surprise from 19.6 & 62.4 GeV AuAu: nucl-ex/0406021 v2 Longitudinal scaling of elliptic flow h’=|h|-ybeam Mark D. Baker

  11. Surprise from 19.6 GeV AuAu: PRC 70 (2004) 021902R Energy & Centrality Dependences Factorize Where are the minijets? Mark D. Baker

  12. 62.4 GeV 200 GeV RAA ratios at 200 and 62.4 GeV (AuAu) PHOBOS • Large variation of RAA with centrality • <Npart> from 61 to 335 • <Ncoll> from 76 to 820 • 0 < b < 10.5 fm PLB (2004) 578297 arXiv:nucl-ex/0405003 Mark D. Baker

  13. 62.4 GeV 200 GeV PHOBOS RAA ratios at 200 and 62.4 GeV (AuAu) Mark D. Baker arXiv:nucl-ex/0405003

  14. 62.4 GeV 200 GeV PHOBOS RAA ratios at 200 and 62.4 GeV (AuAu) For b<10.5 fm: Mark D. Baker arXiv:nucl-ex/0405003

  15. 62.4 GeV 200 GeV PHOBOS RAA ratios at 200 and 62.4 GeV (AuAu) For b<10.5 fm: • Energy-independent • Weak function of Npart, pT Mark D. Baker arXiv:nucl-ex/0405003

  16. 62.4 GeV 200 GeV PHOBOS Another surprise from energy variation For b<10.5 fm: arXiv:nucl-ex/0405003 Varying the beam energy changes: • Initial state: sNN, Ncoll/Npart, Qs(?) • System: , mB, Nch, • Partonic: xT, dE/dx Why does the energy dependence factorize? Mark D. Baker

  17. What Have We Learned?& what are the essential measurements w/ ? http://www.phobos.bnl.gov/Publications/PublicDocuments/PhobosWhitePaper.pdf (or .ps) • We have discovered a strongly interacting medium with extremely high energy density whose description in terms of simple hadronic degrees of freedom is not appropriate. • Study the systematics of this “medium” (vary A & sNN). • Furthermore, we have discovered that much of the data can be expressed in terms of simple scaling rules which suggest the existence of strong global constraints or some kind of universality in the mechanism of the production of hadrons in high energy collisions (possible connection to ideas of parton saturation). • Study these simple scaling rules systematically. • Will they survive further scrutiny?

  18. Benefits of very light ions (SiSi e.g.) • Clearly different from AuAu • study flow, “jet quenching” • Extensive low energy comparison data exists (CC,SiSi,SiAl,SS...) • See BUP refs. 3-15 for a partial listing NA49 (C. Hohne et al.), NPA715 (2003) 474c Mark D. Baker

  19. Benefits of intermediate ions (CuCu) • Npart~100 is better determined for central CuCu than for AuAu • Overlaps both AuAu & SiSi • Geometry different. • study flow, “jet quenching” nucl-ex/0301017 Mark D. Baker

  20. Benefits of a short pp run @ 400-500 GeV • Compare pp@400 to AA@200. • Better systematics within a single experiment. • Better coverage than UA5 • Better statistical power. J.Phys.G30 (2004) S1133 nucl-ex/0403033 Mark D. Baker

  21. Proposed scenario (updated) • Boundary conditions • Run CuCu as the light ion species this year • RHIC will run 7 weeks of pp200 physics • Phobos does not request any pp @ 200 GeV. • 31 - 10 weeks of setup - 7 weeks pp200 • 14 weeks: • 200 GeV CuCu (10 weeks physics) • 62.4 GeV CuCu (3 weeks incl. setup) • 22.5 GeV CuCu (3 days incl. setup) • 400 GeV pp (4 days incl. setup) Mark D. Baker

  22. Fallback Scenario (updated) • Constrained to 10 weeks • 27 weeks of cryo., still 7 weeks of pp200 • RHIC becomes RppC • 31 weeks, but 11 weeks for pp @ 200 GeV • 10 weeks: • 200 GeV CuCu (7 weeks physics) • 62.4 GeV CuCu (2.5 weeks incl. setup) • 22.5 GeV CuCu (3 days incl. setup) Mark D. Baker

  23. Scenarios at a glance d2Nch/dhdf d2N/dydpT HBT d2Nch/dhdf d2N/dydpT HBT d2Nch/dhdf dNch/dh * = including energy-change setup time Mark D. Baker

  24. Run VI + ?? • Highest priority: SiSi @ 3 energies • Other possibilities depend on results • Longer 19.6 GeV AuAu • 200 GeV SiAu • Au-d(yellow) • ??? Mark D. Baker

  25. Summary • Many new interesting results from Phobos • Rate of publication growing exponentially. • “Golden” opportunity in Run V • RHIC tuned for Cu ions • PHOBOS-specific features • Unique h coverage • Total Nch event-by-event • Unique centrality measures • Run CuCu at 200, 62.4 and 22.5 GeV! • Run VI • SiSi at 200, 62.4 and 24 GeV • & base further running on what we learn... Mark D. Baker

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