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Search for Hidden Gauge Vector Bosons and Scalars with the PrimEx Setup

Search for Hidden Gauge Vector Bosons and Scalars with the PrimEx Setup. “Ready-to-Run” Survey Type Experiments. A. Gasparian NC A&T State University, Greensboro, NC. Outline: Suggested experiment for A’ vector boson Suggested experiment for X  scalar boson. Current PrimEx Setup.

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Search for Hidden Gauge Vector Bosons and Scalars with the PrimEx Setup

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  1. Search for Hidden Gauge Vector Bosons andScalars with the PrimEx Setup “Ready-to-Run” Survey Type Experiments A. Gasparian NC A&T State University, Greensboro, NC Outline: • Suggested experiment for A’ vector boson • Suggested experiment for X scalar boson

  2. Current PrimEx Setup • Photon Tagger • Pair Spectrometer with 17 KG x m Dipole magnet • X, Y veto counters in front of HyCal •  2000 channel HyCal Electromagnetic Calorimeter DM_Workshop, Sept. 21, 2010

  3. Current PrimEx Setup • HyCal Calorimeter: • 1200 PbWO4 Crystal counters • 700 Pb-glass counters HyCal size: 118 x 118 cm2 DM_Workshop, Sept. 21, 2010

  4.  Invariant Mass resolution from PrimEx-I M = 135 MeV (0) Range DM_Workshop, Sept. 21, 2010

  5. Suggested Experiment to Search for A’ Boson e-+Pb e’+Pb+A’ A’ e+e- Sizeable acceptance to detect all 3 final state leptons • Non-magnetic • High acceptance • High resolution • Large acceptance for M(e+e-) • “Ready-to-Run” Survey experiment Veto counters DM_Workshop, Sept. 21, 2010

  6. Detection Efficiencies • Can reach low mass range: M(e+e-) = [50 – 300] MeV • <Eff. for e+e-> = 50% • <Eff. for all 3 leptons> = 20% DM_Workshop, Sept. 21, 2010

  7. e+ e- Invariant Mass Resolution MA= 50 MeV MA= 100 MeV  = 1.21 MeV  = 1.6 MeV DM_Workshop, Sept. 21, 2010

  8. e+ e- Invariant Mass Resolution MA= 135 MeV MA= 200 MeV  = 2.35MeV  = 4.31MeV DM_Workshop, Sept. 21, 2010

  9. Measured Energies of Secondary Particles MA= 75 MeV MA= 75 MeV DM_Workshop, Sept. 21, 2010

  10. Polar Angles of Secondary Particles MA= 75 MeV MA= 75 MeV Scatt. e- Polar angle A’ Polar angle DM_Workshop, Sept. 21, 2010

  11. Scattered e- and A’ Co-planarity MA= 75 MeV  = 26 0 DM_Workshop, Sept. 21, 2010

  12. Background Rate in HyCal (Trigger Rate) • Target: 0.5% Pb • Ie = 0.1 A • Run equiv. time 0.2 msec • Total rate on HyCal:  60 MHz Applied Cuts: •  (Ei) > 4 GeV • more than one cluster • Ei < 5.0 GeV • Ei > 0.1 GeV • (cluster separ.) > 15 cm Trigger Rate  3 / 0.2 msec  15 KHz Work is in progress to optimize the Trigger Rate Very Preliminary DM_Workshop, Sept. 21, 2010

  13. Estimated Cross Sections and Count Rates • Estimated Total Cross Section: (reference: Hall A proposal, page #5): (heavy targets): A  100 pb (/10-4)2 (100 MeV/MA)2 • for  = 1x10-4, MA = 100 MeV, we have: A  100 pb • Estimated Rate: Assume: • Electron beam current: Ie = 0.1 A = 6.25x10+11 e/sec • Target: 0.5% Pb target, NPb = 0.9x10+20 Pb atoms/cm2 • Detection Efficiency: 25% NA  Ne xNPbx x(Det. Eff.)  6.25x10+11x0.9x10+20x100x10-12x10-24x0.25  5 A’/hour  120 A’/day DM_Workshop, Sept. 21, 2010

  14. Search for Scalar Bosons (X) • If there are hidden vector bosons, • there should be scalar bosons also to search with: X    DM_Workshop, Sept. 21, 2010

  15. Suggested PrimEx Setup: Two Photon Channel DM_Workshop, Sept. 21, 2010

  16. Detection Efficiencies for Two Photon Experiment (Mx Acceptance) • Good detection acceptance for low invariant mass region: [15 – 45] MeV • Unique way to access this low mass region DM_Workshop, Sept. 21, 2010

  17.  Invariant Mass Resolution MA= 10 MeV MA= 20 MeV  = 0.43 MeV  = 0.34 MeV DM_Workshop, Sept. 21, 2010

  18. Measured Parameters of X+ MA= 25 MeV MA= 25 MeV DM_Workshop, Sept. 21, 2010

  19. Count Rates, Backgroundfor Two photon Experiment • Cross sections typically scale as: A  (/10-4)2 (100 MeV/Mx)2 • for low invariant mass we may expect higher cross sections ( an order of magnitude for this mass range) • Estimated Rate: We assume: • Electron beam current: Ie = 0.1 A = 6.25x10+11 e/sec • Target:  0.5% Pb target • Detection Efficiency: 20% Expect more rate vs. A’ experiment (work is in progress) • Background conditions expected to be better than in A’ experiment • Work is in progress DM_Workshop, Sept. 21, 2010

  20. Summary • We suggest two search experiments for A’ and Scalar gauge bosons in Hall B at Jlab • A’  e+ e- • X    • “Ready-to-Run survey type experiments. • Experimental capabilities: • high detection efficiencies (~25 – 50%) • large acceptance for MA’ and Mx (15 – 300 MeV) • high resolution (1.3 MeV @ MA’ = 75 MeV) • possibility for three particle detection • Work in progress to optimize setup and detection capabilities. DM_Workshop, Sept. 21, 2010

  21. The End DM_Workshop, Sept. 21, 2010

  22. PrimEx-I Experiment: Γ(0) Decay Width • Nuclear targets: 12C and 208Pb; • 6 GeV Hall B tagged beam; • experiment performed in 2004 12C 208Pb DM_Workshop, Sept. 21, 2010

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