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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

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
current primex setup
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

current primex setup1
Current PrimEx Setup
  • HyCal Calorimeter:
    • 1200 PbWO4 Crystal counters
    • 700 Pb-glass counters

HyCal size: 118 x 118 cm2

DM_Workshop, Sept. 21, 2010

invariant mass resolution from primex i
 Invariant Mass resolution from PrimEx-I

M = 135 MeV (0) Range

DM_Workshop, Sept. 21, 2010

suggested experiment to search for a boson
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

detection efficiencies
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

e e invariant mass resolution
e+ e- Invariant Mass Resolution

MA= 50 MeV

MA= 100 MeV

 = 1.21 MeV

 = 1.6 MeV

DM_Workshop, Sept. 21, 2010

e e invariant mass resolution1
e+ e- Invariant Mass Resolution

MA= 135 MeV

MA= 200 MeV

 = 2.35MeV

 = 4.31MeV

DM_Workshop, Sept. 21, 2010

measured energies of secondary particles
Measured Energies of Secondary Particles

MA= 75 MeV

MA= 75 MeV

DM_Workshop, Sept. 21, 2010

polar angles of secondary particles
Polar Angles of Secondary Particles

MA= 75 MeV

MA= 75 MeV

Scatt. e- Polar angle

A’ Polar angle

DM_Workshop, Sept. 21, 2010

scattered e and a co planarity
Scattered e- and A’ Co-planarity

MA= 75 MeV

 = 26 0

DM_Workshop, Sept. 21, 2010

background rate in hycal trigger rate
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

estimated cross sections and count rates
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

search for scalar bosons x
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

detection efficiencies for two photon experiment m x acceptance
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

invariant mass resolution
 Invariant Mass Resolution

MA= 10 MeV

MA= 20 MeV

 = 0.43 MeV

 = 0.34 MeV

DM_Workshop, Sept. 21, 2010

measured parameters of x
Measured Parameters of X+

MA= 25 MeV

MA= 25 MeV

DM_Workshop, Sept. 21, 2010

count rates background for two photon experiment
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

summary
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

the end
The End

DM_Workshop, Sept. 21, 2010

primex i experiment 0 decay width
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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