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Physics With Polarized Protons at RHIC II

Physics With Polarized Protons at RHIC II. Proton Structure and RHIC Spin: A new experimental method to

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Physics With Polarized Protons at RHIC II

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  1. Physics With Polarized Protons at RHIC II • Proton Structure and RHIC Spin: • A new experimental method to • explore the spin structure of the fundamental bound state of QCD • New Opportunities at high luminosities (+ upgrades) • How is a transversely polarized proton different from a longitudinal • polarized proton? What can we learn from the difference? • What is the role of strange quarks in the proton? • Precision measurement of the nucleon (p+3He?) helicity structure. • Precision cross section measurements and their QCD analysis. E. Sichtermann, LBL M. Stratmann, Regensburg M. G. Perdekamp, UIUC/RBRC

  2. The Big Picture:Structure of Basic Building Blocks of Matter ⇔ Fundamental Forces in Nature measurements with new tools + better precision fundamental bound state of matter interaction between the constituents of the bound state theory predictions increasingly quantitative Physics with Polarized Protons at RHIC II

  3. Structure of the Basic Building Blocks of Matter vs Fundamental Forces in Nature Example: Doppler free saturation spectroscopy  Lamb shift Lamb Doppler free saturation spectroscopy hydrogen atom Quantum Electro Dynamics Lamb shift Tomonaga, Feynman, Schwinger Physics with Polarized Protons at RHIC II

  4. A novel experimental method: Probing Proton Spin Structure in High Energy Polarized Proton Collisions at RHIC RHIC pC Polarimeters Absolute Polarimeter (H jet) Siberian Snakes BRAHMS & PP2PP Siberian Snakes RIKEN & BNL Spin Flipper PHENIX STAR Spin Rotators Partial Snake Helical Partial Snake Strong Snake Polarized Source LINAC AGS BOOSTER 200 MeV Polarimeter Rf Dipole AGS Internal Polarimeter AGS pC Polarimeter Physics with Polarized Protons at RHIC II

  5. The Proton as QCD Laboratory q(x) -- G(x) -- ∆q(x) – DVCS -- δq(x) -- Sivers -- ∆G(x) -- ∆q(x) -- ∆s(x) SLAC DIS, polarized-DIS CERN DIS, polarized-DIS FNAL DIS, pp DESY collider-DIS, polarized-DIS JLAB DIS, polarized-DIS RHIC I+II polarized-pp e-RHIC polarized collider DIS GSI-PAX polarized anti-protons 2000 2010 1995 2007 ongoing ongoing  2015 ?  2015 Physics with Polarized Protons at RHIC II

  6. Physics Channels for RHIC II Transverse Spin Physics o Measure transversity-, Sivers- and Boer-Mulders distributions in Drell Yan o AN in direct photon production  direct measurements with good statistical resolution  explore origin of transverse spin phenomena in QCD  study transverse proton spin structure  unique test of factorization & universality for kT-dependent distribution functions  possible connection to orbital angular momentum Polarization of the strange sea o Access ∆s(x) through inclusive anti-Lambda production and charm associated W-production (very luminosity hungry)  study polarization of the strange sea  verify ∆s from DIS (spin crisis!), neutrinos Physics with Polarized Protons at RHIC II

  7. Physics Channels for RHIC II Precision measurement of the proton helicity structure o ∆G(x) and ∆q(x), ∆q(x) with high luminosity in multiple channels with available detector upgrades. Extend measurements to 3He  neutron. (can this be done with high polarization + intensity??)  minimize errors and increase x-coverage of ∆G(x) for precision measurement of the first moment of the spin-dependent gluon distribution ∆G=ʃ∆G(x)dx: minimize errors in  observe scale evolution of the first moment.  global QCD analysis for best knowledge of polarized nucleon structure + pdfs Precision cross section measurements + QCD analysis o Measure cross sections in direct photon production, inclusive jet + hadron production as input to QCD analysis to improve knowledge of  G(x) at large x  Gluon fragmentation function Physics with Polarized Protons at RHIC II

  8. Present knowledge of the Gluon Distribution Function G(x,Q2) J. Pumplin et.al JEHP 0207:012 (2002) CTEQ6: use DGLAP Q2-evolution of quark and gluon distributions to extract q(x,Q2) and G(x,Q2) from global fit to data sets at different scales Q2. error on G(x,Q2) ! +/- 10% Quark and Gluon Distributions H1 + Zeus F2 CTEQ6M up-quarks CDF + D0 Jets gluon CTEQ5M1 10-410-3 10-2 10-1 0.5 x error for d(x,Q2) error for u(x,Q2) down anti-down +/- 5% +/- 5% 10-410-3 10-2 10-1 0.5 x Physics with Polarized Protons at RHIC II

  9. Work in Progress: general working group meeting October 7 +8 at BNL Transverse spin physics: S. Menzel (Bochum), L. Gamberg (Penn State), J. Soffer (Marseille), M. Burkardt (New Mexico), F. Yuan (RBRC), M. Radici (Pavia) (there was also a very well attend RBRC workshop organized by Vogelsang and Yuan in June) Hyperons : Z. Liang (Shandong), Q. Xu (Shandong+LBL), K. Sudoh (KEK) W-physics: P. Nadolsky (Argonne), K. Sudoh (KEK), J. Soffer (Marseille) Beyond the SM: J. Soffer (Marseille), D. Maitre (Zurich) + usual RHIC spin crowd Work in progress; eg. projections for access to Strange polarization in lambda production. Final document will be based on written contributions from working group participants  December Physics with Polarized Protons at RHIC II

  10. Transverse spin program at RHIC is luminosity limited Physics channel Luminosity? RHIC by 2009 at 200 GeV ∫Ldt ~275pb-1delivered ∫Ldt ~100pb-1 accepted (eg. PHENIX: vertex cut, trigger efficiencies, duty factor)  ∫Ldt ~25 pb-1 transverse AN yes, very good AN(back-to-back) good AT (Collins FF) fair AT (Interference FF) limited ATT (Jets) not studied experimentally AT (Drell Yan) --- ATT( Drell Yan) --- Direct photons --- (AN,AT(CFF, IFF)) RHIC II • Dedicated Drell Yan experiment for transverse spin physics at PHOBOS IR? Physics with Polarized Protons at RHIC II

  11. Transversity vs Sivers vs Boer-Mulders in Drell Yan Transversity : correlation between transverse proton spin and quark spin Sivers : correlation between transverse proton spin and quark transverse momentum Boer/Mulders: correlation between transverse quark spin and quark transverse momentum Physics with Polarized Protons at RHIC II

  12. Sivers-Asymmetries, AT in Drell Yan (S. Menzel) Sensitivity to anti-quark Sivers distribution (not probed at GSI) Sign with respect to DIS! Brodsky, Hwang, Schmidt Collins Boer, Mulders, Pijlman Belitsky, Ji, Yuan Physics with Polarized Protons at RHIC II

  13. Sivers-Asymmetries, AT in Drell Yan (S. Menzel) Sensitivity to anti-quark Sivers distribution (not probed at GSI) Physics with Polarized Protons at RHIC II

  14. Sivers-Asymmetries, AT in Drell Yan (S. Menzel) STAR for 125pb-1 Dedicated DY Experiment 1250 pb-1 (fraction of transverse Running + mini quads) “entrance door” for DIS colleagues Interessted in e-RHIC Physics with Polarized Protons at RHIC II

  15. Projections for pp at 200 GeV and 1250 pb-1 ATT for Drell Yan with dedicated DY detector projections for 1250pb-1 of running, 5-10% higher polarization, with RHIC II luminosities and large acceptance Drell Yan 1.25fb-1, large acceptance detector for Drell Yan This measurement appears to be also possible at 500 GeV Physics with Polarized Protons at RHIC II

  16. Physics with Polarized Protons at RHIC II

  17. K. Sudoh Physics with Polarized Protons at RHIC II

  18. K. Sudoh AL(W+) sensitivity to ∆s seems difficult, work in progress! AL(W+) Physics with Polarized Protons at RHIC II

  19. Summary of RHIC II Physics Channels for Polarized Protons • Active studies underway to evaluate the benefit • of RHIC II luminosities and upgrades to the spin • physics program (complete in December) • Physics case under study: • How is a transversely polarized proton different from a longitudinal • polarized proton? What can we learn from the difference? • What is the role of strange quarks in the proton? • Precision measurement of the nucleon (p+3He?) helicity structure. • Precision cross section measurements and their QCD analysis. Physics with Polarized Protons at RHIC II

  20. The Structure of Matter: The Atomic Hypothesis If, in some cataclysm, all of scientific knowledge were to be destroyed, and only one sentence passed on to the next generation of creatures, what statement would contain the most information in the fewest words? I believe it is the atomic hypothesis, that all things are made of atoms -- little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another. In that one sentence, you will see, there is an enormous amount of information about the world, if just a little imagination and thinking are applied. Richard Feynman Physics with Polarized Protons at RHIC II

  21. An Old (and fundamental!) Question: What is the structure of matter in the Universe? Leukipp and Demokrit (~ 450-400 bc) formulated the atomic hypothesis: There are small particles, atoms, of which all matter is made and which cannot be divided in smaller parts Physics with Polarized Protons at RHIC II

  22. Summary Structure and origin of matter have been subject of century long investigation first in philosophy and over the last two centuries also in the natural sciences. We well may be the generation who will see the solution of a 2500 year old puzzle. This are exciting times! RHIC Spin (I+II) provides a powerful new experimental method to study the structure of the nucleon Physics with Polarized Protons at RHIC II

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