Physics With Polarized Protons at RHIC II E. Sichtermann, LBL M. Stratmann, Regensburg M. G. Perdekamp, UIUC/RBRC o Proton Structure and RHIC Spin: A new experimental method to explore the spin structure of the fundamental bound state of QCD o 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+ 3 He?) helicity structure. Precision cross section measurements and their QCD analysis.

Physics with Polarized Protons at RHIC II2 November 11 th The Big Picture: Structure of Basic Building Blocks of Matter ⇔ Fundamental Forces in Nature fundamental bound state of matter interaction between the constituents of the bound state measurements with new tools + better precision theory predictions increasingly quantitative

Physics with Polarized Protons at RHIC II3 November 11 th Structure of the Basic Building Blocks of Matter vs Fundamental Forces in Nature hydrogen atom Quantum Electro Dynamics Doppler free saturation spectroscopy Lamb shift Example: Doppler free saturation spectroscopy  Lamb shift Tomonaga, Feynman, Schwinger Lamb

Physics with Polarized Protons at RHIC II November 11 th AGS LINAC BOOSTER Polarized Source Spin Rotators Partial Snake Siberian Snakes 200 MeV Polarimeter AGS Internal Polarimeter Rf Dipole RHIC pC Polarimeters Absolute Polarimeter (H jet) P HENIX B RAHMS & PP2PP S TAR Siberian Snakes AGS pC Polarimeter Helical Partial Snake Strong Snake Spin Flipper A novel experimental method A novel experimental method: Probing Proton Spin Structure in High Energy Polarized Proton Collisions at RHIC RIKEN & BNL

Physics with Polarized Protons at RHIC II5 November 11 th The Proton as QCD Laboratory  2000  2010  1995  2007 ongoing  2015 ?  2015 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

Physics with Polarized Protons at RHIC II6 November 11 th Physics Channels for RHIC II Transverse Spin Physics o Measure transversity-, Sivers- and Boer-Mulders distributions in Drell Yan o A N 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 k T -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 II7 November 11 th 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 3 He  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 II8 November 11 th Present knowledge of the Gluon Distribution Function G(x,Q 2 ) J. Pumplin et.al JEHP 0207:012 (2002) x gluon down up-quarks anti-down Quark and Gluon Distributions error on G(x,Q 2 ) error for u(x,Q 2 ) +/- 10% +/- 5% error for d(x,Q 2 ) x CTEQ6: use DGLAP Q 2 -evolution of quark and gluon distributions to extract q(x,Q 2 ) and G(x,Q 2 ) from global fit to data sets at different scales Q 2. H1 + Zeus F 2 CDF + D0 Jets CTEQ5M1 CTEQ6M !

Physics with Polarized Protons at RHIC II9 November 11 th 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 II10 November 11 th Transverse spin program at RHIC is luminosity limited A N yes, very good A N (back-to-back) good A T (Collins FF) fair A T (Interference FF) limited A TT (Jets) not studied experimentally A T (Drell Yan) --- A TT ( Drell Yan) --- Direct photons --- (A N,A T (CFF, IFF)) RHIC by 2009 at 200 GeV ∫Ldt ~275pb -1 delivered ∫Ldt ~100pb -1 accepted (eg. PHENIX: vertex cut, trigger efficiencies, duty factor)  ∫Ldt ~25 pb -1 transverse RHIC II Physics channel Luminosity?  Dedicated Drell Yan experiment for transverse spin physics at PHOBOS IR?

Physics with Polarized Protons at RHIC II11 November 11 th 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 Transversity vs Sivers vs Boer-Mulders in Drell Yan

Physics with Polarized Protons at RHIC II12 November 11 th Sivers-Asymmetries, A T 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 II13 November 11 th Sivers-Asymmetries, A T in Drell Yan (S. Menzel) Sensitivity to anti-quark Sivers distribution (not probed at GSI)

Physics with Polarized Protons at RHIC II14 November 11 th Sivers-Asymmetries, A T 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 II15 November 11 th Projections for pp at 200 GeV and 1250 pb -1 A TT 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 II16 November 11 th

Physics with Polarized Protons at RHIC II17 November 11 th K. Sudoh

Physics with Polarized Protons at RHIC II18 November 11 th K. Sudoh A L (W + ) sensitivity to ∆s seems difficult, work in progress!

Physics with Polarized Protons at RHIC II19 November 11 th Summary of RHIC II Physics Channels for Polarized Protons o Active studies underway to evaluate the benefit of RHIC II luminosities and upgrades to the spin physics program (complete in December) o 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+ 3 He?) helicity structure. Precision cross section measurements and their QCD analysis.

Physics with Polarized Protons at RHIC II20 November 11 th 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 II21 November 11 th Leukipp and Demokrit (~ bc) formulated the atomic hypothesis: There are small particles, atoms, of which all matter is made and which cannot be divided in smaller parts An Old (and fundamental!) Question: What is the structure of matter in the Universe?

Physics with Polarized Protons at RHIC II22 November 11 th 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