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“We had a BLAST at MIT-Bates”

“We had a BLAST at MIT-Bates”. BLAST: A Detector for Internal Target Experiments. Introduction Overview Present Results Outlook. John Calarco, EINN 2005. Approved BLAST Scientific Program Form Factor Measurements: Q 2  1.0 (GeV/c) 2

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“We had a BLAST at MIT-Bates”

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  1. “We had a BLAST at MIT-Bates” BLAST: A Detector for Internal Target Experiments • Introduction • Overview • Present Results • Outlook John Calarco, EINN 2005 EINN 2005

  2. Approved BLAST Scientific Program Form Factor Measurements: Q2  1.0 (GeV/c)2 Proton Charge and Magnetism Elastic Scattering with Polarized Beam and H Target (01-01) Neutron Charge and Magnetism and Deuteron Electromagnetic Structure Quasi-elastic Scattering with Polarized Beam and D Target (89-12 and 91-09) Elastic scattering off Tensor and Vector Polarized Deuterium (00-03 and 03-02) EINN 2005

  3. General Kinematics for Polarized e Scattering on a Polarized Target EINN 2005

  4. 500MeV Linac recirculated to reach up to 1GeV • Inject into South Hall Ring • Polarization maintained by Siberian snake • Polarization monitored real time by Compton Polarimeter • Internal Target located in the ring vacuum Bates Linac EINN 2005

  5. The BLAST Spectrometer BEAM DRIFT CHAMBERS TARGET • Left-right symmetric detector • simultaneous parallel and perpendicular asymmetry determination • Large acceptance • covers 0.1GeV2 ≤ Q2 ≤ 1GeV2 • out-of-plane measurements • DRIFT CHAMBERS • momentum determination, particle identification • CERENKOV COUNTERS • electron/pion discrimination • SCINTILLATORS • TOF, particle identification • NEUTRON COUNTERS • neutron determination • MAGNETIC COILS • 3.8kG toroidal field CERENKOV COUNTERS BEAM NEUTRON COUNTERS SCINTILLATORS EINN 2005

  6. BLAST: Configuration used for present data EINN 2005

  7. EINN 2005

  8. ep Elastic Kinematic Correlation EINN 2005

  9. GE/GM Results EINN 2005

  10. e-d elastic scattering: GC GM GQ • GQ > D-state > Tensor Force • Rosenbluth Separation • 3rd Measurement to separate 3 form factors • Tensor Asymmetry in e-d elastic scattering Motivation: Why T20 EINN 2005

  11. Protons + ? Deuterons e- left, d+ right e- right, d+ left e-d Elastic Event Selection • Mass: timing & tracking Blue: everything Red: after coplanarity cut • Kinematics: pe=24MeV d=1o … … EINN 2005

  12. T20and T21 foredelastic scattering EINN 2005

  13. Difference between T20 and theory EINN 2005

  14. Helicity dependent T10and T11from ed elastic scattering EINN 2005

  15. GM from world A(Q2) and BLAST T20 , T21 , and helicity dependent T11 EINN 2005

  16. Beam-Vector Asymmetry for D(e,e’p) QES EINN 2005

  17. Beam-Vector Asymmetry (cont.) EINN 2005

  18. Tensor Asymmetry Results EINN 2005

  19. Potential Dependence • Monte Carlo for Bonn, Paris, and V18 potentials compared to BLAST data • Potential dependence small compared to MEC and IC contributions EINN 2005

  20. GEn from Avedin polarized D(e,e’n) EINN 2005

  21. Conclusions and Outlook • World-class data forGpE/GpM , GnE , D(e,e’)elasticT20, T21 , and helicity dependent T11, D(e,e’p) QES AVedandATd,, • InclusiveH(e,e’)XandD(e,e’)X • Analysis still in progress • Many other channels to be analyzed: H(e,e’p)p0 , H(e,e’n)p+ , H(g,np+) , etc.. • Will BLAST run again at another facility? EINN 2005

  22. BLAST COLLABORATION R. Alarcon, E. Geis, J. Prince, B. Tonguc, A. Young Arizona State University, Tempe, AZ 85287 J. Althouse, C. D’Andrea, A. Goodhue, J. Pavel, T. Smith, Dartmouth College, Dartmouth, NH D. Dutta, H. Gao, W. Xu Duke UniversityDurham, NC 27708-0305 H. Arenhövel, Johannes Gutenberg-Universität, Mainz, Germany T. Akdogan, W. Bertozzi, T. Botto, M. Chtangeev, B. Clasie, C. Crawford, A. Degrush, K. Dow, M. Farkhondeh, W. Franklin, S. Gilad, D. Hasell, E. Ilhoff, J. Kelsey, M. Kohl, H. Kolster, A. Maschinot, J. Matthews, N. Meitanis, R. Milner, R. Redwine, J. Seely, S. Sobczynski, C. Tschalaer, E. Tsentalovich, W. Turchinetz, Y. Xiao, C. Zhang, V. Ziskin, T. Zwart Massachusetts Institute of Technology, Cambridge, MA 02139 and Bates Linear Accelerator Center, Middleton, MA 01949 J. Calarco, W. Hersman, M. Holtrop, O. Filoti, P. Karpius, A. Sindile, T. Lee University of New Hampshire, Durham, NH 03824 J. Rapaport Ohio University, Athens, OH 45701 K. McIlhany, A. Mosser United States Naval Academy, Annapolis, MD 21402 J. F. J. van den Brand, H. J. Bulten, H. R. Poolman Vrije Universitaet and NIKHEF, Amsterdam, The Netherlands W. Haeberli, T. Wise University of Wisconsin, Madison, WI 53706 EINN 2005

  23. The BLASTers EINN 2005

  24. GnM EINN 2005

  25. Asymmetries AL and AR EINN 2005

  26. mGE/GM from ep Elastic EINN 2005

  27. Tensor Asymmetry (cont.) EINN 2005

  28. GE/GM — World Data EINN 2005

  29. BLAST + World Data GE and GM Results EINN 2005

  30. Detector Performance • All detectors operated at or near designed level • Drift chambers ~98% efficient per wire • TOF resolution of 300ps • Clean event selection • Cerenkov counters 85% efficient in electron/pion discrimination • Neutron counters 10% (25-30%) efficient in left (right) sectors • Reconstruction resolutions good but still being improved EINN 2005

  31. T20 for edelastic scattering EINN 2005

  32. GnEfrom D(e,e’n) EINN 2005

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