1. Experiment Rosen07: Measurement of R =  L /  T on Deuterium in the Nucleon Resonance Region. 1  Physics  Data Analysis  Cross Section calculation  L/T Separations Ibrahim H. Albayrak Hampton University

2. 2  ROSEN07 (E06-009) is the second phase of the experiment JAN05(E04-001) with higher Q 2 data.  ROSEN07 is combination of two experiments:  Measurement ofR =  L /  T on Deuterium in the Nucleon Resonance Region.(I.Albayrak)  Measurement of R =  L /  T on Deuterium in the Nucleon Resonance Region.(I.Albayrak)  Measurement ofR =  L /  T on Nuclear targets in the Nucleon Resonance Region.(Vahe Mamyan)  Measurement of R =  L /  T on Nuclear targets in the Nucleon Resonance Region.(Vahe Mamyan)  JAN05 is combination of two experiments:  Measurement ofR =  L /  T on Deuterium in the Nucleon Resonance Region.(Ya Li)  Measurement of R =  L /  T on Deuterium in the Nucleon Resonance Region.(Ya Li)  Measurement ofR =  L /  T on Nuclear targets in the Nucleon Resonance Region.(Ya Li)  Measurement of R =  L /  T on Nuclear targets in the Nucleon Resonance Region.(Ya Li) ROSEN07 and JAN05 experiments

3. F L, F 1, F 2 and R fundamental Structure Function Measurements on Deuterium. - These structure functions provide us important information about internal structure of nucleon, i. e. distribution of quarks and gluons inside the nucleus. Since these are fundamental measurements, they allow a variety of physics issues to be addressed, such as: – Structure Function Moments Lattice QCD comparisons Singlet and non-singlet distribution functions – Quark-hadron duality studies – Neutron form factors. – Support Broad Range of Deuteron Physics Spin structure functions BONUS (BOund NUcleon Structure) neutron structure functions - Hall B experiment for NEUTRON cross sections via spectator tagging. 3 Physics Physics Motivation

4. Structure functions (F1 and F2) which have the Information of the nucleon’s internal structure. Physics of Interest (Nucleon Structure) Calculable in Quantum Electrodynamics (QED) { Physics Structure Functions: F1, F2, FL 4

5. Where:  = flux of transversely polarized virtual photons  = relative longitudinal flux Rosenbluth Separation Technique: Physics 5 longitudinalTransverse

6. The non-singlet moments can only be determined from differences of proton and neutron moments. 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 Assuming a charge-symmetric sea, n-p isolates the non-singlet WhereWhere Need to pin down non-singlet (n-p) to extract singlet. Need to pin down non-singlet (n-p) to extract singlet. M d – 2M p = ∫ x n-2 (F d ∙ f – 2F p )dx yields non-singlet distribution 6 Physics Moments of the Structure Functions Moments Calculated on the lattice at Q 2 = 4 GeV 2 M n (Q 2 ) = ∫dx x n-2 F(x,Q 2 )

7. JAN05 ROSEN07 New data with higher Q 2 And new epsilon points for LT separation Physics ROSEN07 experiment is the second phase of this experiment, the first phase was JAN05 experiment… Purely New data with high Q 2 above 3 GeV 7

8. Current Status and Update  Detector Calibrations  Kinematic Corrections  Dead Times  Efficiencies  Background Estimation and Subtraction:  Target Density Correction  Acceptance Corrections  Bin-centering corrections  Radiative corrections  Iteration Procedure  Systematic Uncertainties  Extracting Differential Cross Sections  Doing Rosenbluth L/T Separation  Moment extraction  N-p analysis 8 Experiment & Data analysis

9. Data to Monte Carlo simulation comparisons… Experiment & Data analysis 9

10. Drift Chamber Positions Offsets Checked optics elements, magnets fields, matrix elements and no difference found from previous data. Significantly different from previous data!!! Could it be because of DC offsets? 10

11. Drift Chamber Positions Offsets X direction Experiment & Data analysis Without X pos offset Peak gets wider with any x offset Must be Straight. Gets tilted with any x offset No DC offset in X (vertical) direction! For drift chamber position offset study I studied the width of the Elastic peak and Xptar. The narrowest the peak the best the position. XpTar plots should not be correlated with DC positioning. With X pos offset 11

12. Drift Chamber Positions Offsets Y Direction Experiment & Data analysis Ytar plot for Carbon target should be narrowest with correct positions Peak gets narrower Slope of the valley gives the best Y offset! With Y pos offset 12 Without Y pos offset There is about 0.45 mm relative offset (distance) between the DCs

13. Offsets for Drift Chamber Positions Experiment & Data analysis Before After After correction y pos gets narrow, which indicates that we are doing the right thing. After putting the relative offset 0.45 mm for Y position we get better comparison! 13

14. Target Position Study (Again) Experiment & Data analysis After getting correct position information for Drift Chambers, Target position study needed to be redone. C -0.105 0.0928 D2 -0.0665 0.0382 Al -0.116 0.173 Fe -0.0861 0.0972 Cu -0.0764 0.0749 Del X (cm) Del Z (cm) 14

15. Experiment & Data analysis Two simulation runs compared with and without radiative corrections to get the radiative effect on peak position. Elastic Study (Kinematic Corrections) And correct elastic peak position calculated after subtracting the radiative effect. 15

16. Experiment & Data analysis There is not enough data to do a precise kinematic offset study! Elastic Study (Kinematic Corrections) Two Photon experiment has enough number of elastic H data. They could provide more precise results. 16 A possible 0.3 mrad Theta offset. On average it gives better results. All this data is consistent with very small (> 10 -4 ) E and E’ offsets

17. Experiment & Data analysis Monte Carlo ratio method is used to extract data cross sections: We can simulate Monte Carlo data using a cross section model to obtain Y MC (E',q) = L*  mod *(  E  W)*A MC (E',q) Taking ratio to data and assuming that A MC = A, yields  d  /dWdE' =  mod * (Y(E',q)/Y MC (E',q)) (MC ratio method) Cross Sections Extraction Method 17 Peter Bosted’s model used as input model. And this data has helped in the development of this model.

18. Experiment & Data analysis Cross Sections (preliminary) 18

19. And L/T Separations… 19 Experiment & Data analysis Here is some almost final rosenbluth separation plots for 2 different W2,Q2 pairs Advantage of this method: Systematic errors cancel.

20. And L/T Separations… Plots of R,first one have Q2 range 0.5-2.25 second one Q2 range 2.25-4.5 for Carbon. 20 Experiment & Data analysis

21. Summary Calibrations are done. Charge symmetric background subtraction, radiative corrections and other corrections are mostly done. Some L/T separations have already been done (Vahe). Continue data analysis L/T separations Moment extractions n-p analysis 21 Experiment & Data analysis