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

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 A. Gasparian DM_Workshop, Sept. 21, 2010

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

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

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

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

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

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

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

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

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

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 A. Gasparian DM_Workshop, Sept. 21, 2010

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 A. Gasparian DM_Workshop, Sept. 21, 2010

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

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

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 A. Gasparian DM_Workshop, Sept. 21, 2010

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

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

Count Rates, Background for 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 A. Gasparian DM_Workshop, Sept. 21, 2010

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. A. Gasparian DM_Workshop, Sept. 21, 2010

The End A. Gasparian DM_Workshop, Sept. 21, 2010

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