TheThe E-906E-906 // SeaQuestSeaQuest experimentexperiment atat FermilabFermilab Markus Diefenthaler University of Illinois at Urbana-Champaign TheThe SeaQuestSeaQuest collaborationcollaboration ● Abilene Christian University: Donald ● Los Alamos National Laboratory: Christine Isenhower, Tyler Hague, Rusty Towell, Shon Aidala, Gerry Garvey, Mike Leitch, Han Liu, Ming Watson Liu, Pat McGaughey, Joel Moss, Andrew Puckett ● Academia Sinica: Wen-Chen Chang, Yen-Chu ● University of Maryland: Betsy Beise, Kazutaka Chen, Shiu Shiuan-Hal, Da-Shung Su Nakahara ● Argonne National Laboratory: John Arrington, ● University of Michigan: Chiranjib Dutta, Donald F. Geesaman (co-spokesperson), Wolfgang Lorenzon, Richard Raymond, Michael Kawtar Hafidi, Roy Holt, Harold Jackson, David Stewart Potterveld, Paul E. Reimer (co-spokesperson), Joshua Rubin ● National Kaohsiung Normal University: Rurngsheng Guo, Su-Yin Wang ● University of Colorado: Ed(ward) Kinney, Joseph Katich, Po-Ju Lin ● University of New Mexico: Younus Imran ● Fermi National Accelerator Laboratory: Chuck ● RIKEN: Yoshinori Fukao, Yuji Goto, Atsushi Brown, Dave Christian, Jin-Yuan Wu Taketani, Manabu Togawa ● University of Illinois: Bryan Dannowitz, Markus ● Rutgers University: Lamiaa El Fassi, Ron Diefenthaler, Bryan Kerns, Naomi C.R Makins, Gilman, Ron Ransome, Brian Tice, Ryan R. Evan McClellan, Jen-Chieh Peng Thorpe, Yawei Zhang ● KEK: Shin'ya Sawada ● Tokyo Tech: Shou Miyaska, Kenichi Nakano, Florian Sanftl, Toshi-Aki Shibata ● Ling-Tung University: Ting-Hua Chang ● Yamagata University: Yoshiyuki Miyachi2 TheThe innerinner structurestructure ofof thethe nucleonnucleon origin of origin of the nucleon sea nucleon spin nucleons in nuclei 3 ComplimentaryComplimentary processesprocesses Deep-inelastic scattering Drell-Yan scattering 4 AA laboratorylaboratory forfor seasea quarksquarks The Drell-Yan process x target x beam beam: valence quarks at high-x target: sea quarks at low/intermediate-x 5 ProbingProbing thethe protonproton seasea ● perturbative sea: g → qq, flavor-symmetric, u = d ● analysis of cross-section differences → sensitivity to d - u in valence region ● measurement of cross-section ratios → sensitivity to u and d in proton sea 6 InsightsInsights intointo thethe protonproton seasea d > u alternate degrees of freedom? 7 SeaQuestSeaQuest probingprobing thethe protonproton seasea Global NLO PDF fit extend measurement SeaQuest: Syst. ~ 1% 8 NucleonsNucleons embeddedembedded inin nucleinuclei ● Do nucleons change their internal properties when embedded in a nucleus? Fermi motion ● Is confinement influenced by the nuclear medium? ● Do quarks and gluons play any role in the understanding of nuclear forces? ● Can the model of nuclear forces be replaced by a fundamental theory based on the strong interaction between quarks and gluons? 9 TheThe EMCEMC effecteffect antishadowing shadowing 10 TheThe EMCEMC effecteffect inin Drell-YanDrell-Yan valence quark effect? no antishadowing shadowing antiquark feature? 11 TheThe innerinner structurestructure ofof aa nucleusnucleus ● nuclear force mediated by meson exchange large effects to antiquark PDF predicted as x increases no antiquak enhancement ● Where are the nuclear pions? 12 Spin-orbitSpin-orbit correlationscorrelations ● angular dependence of the Drell-Yan cross-section: ● Lam-Tung relation: Boer-Mulders TMD 13 TheThe SeaQuestSeaQuest missionmission ● significant increase in physics reach ● unique access to sea quarks at high-x ● What is the structure of the nucleon? ● What is d / u? ● What are the origins of the sea quarks? ● What is the high-x structure of the proton? ● How are quark spin and orbital motion correlated? ● What is the struture of nucleonic matter? ● Where are the nuclear pions? ● Is antishadowing a valence effect? ● Do colored partons lose energy in cold nuclear matter? 14 TheThe protonproton beambeam forfor SeaQuestSeaQuest ● extracted from Fermilab Main Injector fixed target beam lines Tevatron 800 GeV Main Injector 120 GeV 12 ● 2x10 protons / s for 5s spills each minute ● 120 GeV proton beam instead of a 800 GeV proton beam (as used for E-866 / NuSea): ● Drell-Yan cross section scales as 1/s ● decay (dominant background) scales as s 15 ● 50x luminosity as E-866 (for same rate) TheThe SeaQuestSeaQuest targettarget luminosity: liquid 3.4x1035/cm2/s hydrogen liquid deuterium Carbon Calcium Tungsten 16 TheThe SeaQuestSeaQuest spectrometerspectrometer ~25m spectrometer magnet focusing magnet hadron absorber hadronhadron absorber hodoscope beam(iron dumpwall) tracking 17 ReuseReuse andand recylcerecylce 18 ““JoyJoy andand toiltoil asas FermilabFermilab sendssends firstfirst particlesparticles toto SeaQuest”SeaQuest” Fermilab Today: On the night of March 7, SeaQuest celebrated the detection of their first particles – a new milestone for the experiment. 19 TheThe futurefuture ofof SeaQuest:SeaQuest: PolarizedPolarized Drell-YanDrell-Yan measurementsmeasurements atat FermilabFermilab TheThe SiversSivers functionfunction ● transverse-momentum dependent PDF: ● rather exotic in being naive-time-reversal-odd ↔ initial (Drell-Yan) and final state (SIDIS) interactions → single-spin asymmetries: ● close relationship to quark orbital angular momentum ● challenging the concept of factorization and universality ● fundamental QCD prediction: ● remains to be experimentally tested ● polarized Drell-Yan measurement required 21 PolarizedPolarized Drell-YanDrell-Yan experimentsexperiments in 2014: well-understood experiment, optimized for Drell-Yan sensitive to valence quark effects → large asymmetries expected → sign, magnitude and shape of the Sivers effect 22 ReestablishingReestablishing spinspin atat FermilabFermilab * based on RHIC 4-helical dipole design polarized H- ion source superconducting siberiansiberian snakessnakes* 75% polarization enginiering & superconducting fabrication: 2yr spin rotator 23 TheThe SeaQuestSeaQuest missionmission unique laboratory for sea quarks at high-x → structure of nucleons and nucleonic matter finally: commissioning of the experiment → data taking until shutdown in April 2012 due to main-injector update (~11 months) → continue data taking in 2013 exciting extensions possible 24.