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Data Analysis of F2 and R in Deuterium and Nuclei

Data Analysis of F2 and R in Deuterium and Nuclei. Vahe Mamyan Ibrahim Albayrak. Physics Experiment Setup HMS Detectors Calibrations Data Analysis Cross Section calculation. Hampton University. Measurement of R = s L / s T on Deuterium in the Nucleon Resonance Region.

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Data Analysis of F2 and R in Deuterium and Nuclei

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  1. Data Analysis of F2 and R in Deuterium and Nuclei Vahe Mamyan Ibrahim Albayrak • Physics • Experiment Setup • HMS Detectors • Calibrations • Data Analysis • Cross Section calculation Hampton University

  2. Measurement of R = sL / sT on Deuterium in the Nucleon Resonance Region. Physics

  3. Transverse longitudinal mIxEd Inclusivee + d  e + X Scattering Rosenbluth Separation Technique: Where:  = flux of transversely polarized virtual photons  = relative longitudinal flux

  4. New data with high Q^2 above 3 And new epsilon points for LT separation ROSEN07 JAN05

  5. Physics • FL, F1, F2 Fundamental Structure Function Measurements on Deuterium • Structure Function Moments • Lattice QCD comparisons • Singlet and non-singlet distribution functions • Support Broad Range of Deuteron Physics • Elastic form factors • Spin structure functions • Structure functions from deuterium cross sections • BONUS neutron structure functions • Important input for neutrino physics • Quark-hadron duality studies

  6. FL can probe the gluon distributions….. • Nucleon structure composed of singlet (gluons, sea) and non-singlet (valence) distributions • At moderate x (~ 0.3), singlet comparable to non-singlet 1

  7. ∫(Fd – 2Fp)dx yields non-singlet distribution • The non-singlet moments can only be determined from differences of proton and neutron moments. • Assuming a charge-symmetric sea, n-p isolates the non-singlet • Need to pin down non-singlet (n-p) to extract singlet (FL) • OPEN QUESTION IN QCD: Do we have valence, or intrinsic, glue? Need FLd – 2FLp • “..highly precise deuteron data - due to the above aspects - • are forming a conditio sine qua non for any real precision test of QCD.” – Johannes Bluemlein

  8. Moments of the Structure Functions Mn(Q2) = ∫dxxn-2F(x,Q2) Calculated on the lattice at Q2 = 4 GeV2 Well understood in QCD Operator Product Expansion 1 0

  9. Preliminary cross section for Deuterium…

  10. Data to Monte Carlo simulation comparisons…

  11. In Conclusion… • No L/T separated resonance region (large x) data on deuterium currently • Impossible to extract high precision moments • Compare to lattice • FL to access singlet

  12. Experimental Setup HMS Detector Hut Target Scattering Chamber e´- e- Electron Beam X

  13. HMS Detectors Drift Chambers, Horizontal and vertical Electro-magnetic calorimeter Gas Cerenkov Vertically and Horizontally segmented hodoscopes

  14. Calibrations • BCM calibration • A new BCM calibration script is written based on C++/ROOT. • Drift Chamber and TOF calibration • The calibration is done by one command, just run a batch job and result is ready, quality is checked by examining the PS files produced after calibration. • Calorimeter calibration • Gas Cerenkov calibration

  15. BCM calibration

  16. BCM calibration-cont.

  17. Calorimeter calibration

  18. Gas Cerenkov calibration

  19. Data Analysis • Particle identification • Background subtraction • Acceptance calculation • Corrections • Cross section calculation

  20. Particle Identification Most background come from negative pions. Calorimeter and Gas Cerenkov are used to reject these pions. HMS P=0.44 GeV, Θ=75 degree Rejection factor is 100:1.8

  21. Background subtraction Electrons produced from charge-symmetric πo and γ production and decay are background for us. For this purpose special runs are taken with HMS at positive polarity. Since the background is charge-symmetric, it allows to count the number of positrons and subtract it from our data.

  22. Acceptance calculation • Acceptance is calculated for each Θ-W2 bin. • Number of Θ bins is fixed, 20 bins. • Size of the W bin is 0.04 GeV2.

  23. Corrections • Target boiling. • Radiative corrections.

  24. Cross Section calculation Measured CS Rad. corrected CS Bin correction factor Bin corrected cross section

  25. Cross Section • No charge symmetric background subtracted

  26. Summary • Calibrations are mostly done. • Implement charge symmetric background subtraction. • Continue data analysis

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