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

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting Physics e e  

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting 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

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting Where:  = flux of transversely polarized virtual photons  = relative longitudinal flux Rosenbluth Separation Technique: Physics

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting 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 Singlet and non-singlet distribution functions Lattice QCD comparisons – 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. Physics Physics Motivation

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting F L, F 1, F 2 structure functions Physics F 1 is transverse structure function F 2 is mixed structure function describes the momentum distribution of the quarks inside the nucleon. describes the momentum distribution of the quarks inside the nucleon. longitudinalTransverse MIxEdMIxEdMIxEdMIxEd

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting Physics This Data Provides Constraints on Gluon Distributions in two Ways: 1- F L can probe the gluon distributions….. Nucleon structure composed of singlet (gluons, sea) and non-singlet (valence) distributions Nucleon structure composed of singlet (gluons, sea) and non-singlet (valence) distributions At moderate x (~ 0.3), singlet comparable to non-singletAt moderate x (~ 0.3), singlet comparable to non-singlet = > Singlet and non-singlet separation provides extra constraint on gluon distribution. = > Singlet and non-singlet separation provides extra constraint on gluon distribution. F L (x,Q 2 ) = (  s (Q)/2  )x 2  dy/y 3 [8/3F 2 (y,Q 2 ) + 2∑e i 2 (y-x)g(y,Q 2 )] + … 2- n-p provides non-singlet and therefore singlet 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 Need to pin down non-singlet (n-p) to extract singlet. Need to pin down non-singlet (n-p) to extract singlet. ∫(F d – 2F p )dx yields non-singlet distribution

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting Physics Moments of the Structure Functions Moments Calculated on the lattice at Q 2 = 4 GeV 2 For proton, n= 2 F 2 moment = / For deuteron, n=2 F 2 moment / nucleon = / Since Lattice calculates only valence quarks, singlet/non-singlet separation allows for precise Lattice comparisons. M n (Q 2 ) = ∫dx x n-2 F(x,Q 2 )

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting Deuteron, Neutron, and non- singlet L/T Moments - Can extract low Q 2 neutron moments with minimal uncertainties from nuclear corrections! - Below x < 0.7 is the safe region to extract neutron moments because nuclear corrections are small in this region. - Neutron L/T SFs can be extracted using proton and deuteron L/T SFs combined with BoNuS neutron cross sections. Physics

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting JAN05 ROSEN07 New data with high Q 2 above 3 GeV And new epsilon points for LT separation Physics ROSEN07 experiment is the second phase of this experiment, the first phase was JAN05 experiment…

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting Current Status and Update Experiment & Data analysis Detector Calibration Completed Calorimeter Eff. Completed Cerenkov Eff. Completed Tracking Eff. Detailed study in progress Trigger Eff. Detailed study in progress Computer Dead Time Detailed study in progress Acceptance Corrections Needs to be redone Beam Position Stability Study Completed Beam Position Offsets Needs to be redone Target Position Offsets Needs to be redone Optics Checks Preliminary Checks Charge Symmetric Background Completed Radiative Corrections Iterating Cross Sections Iterating

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting Experiment & Data analysis Charge Symmetric Background Subtraction…(From Vahe) Cross Section(CS) fit function has exponential form, with constraint CS=0 at E’=Ebeam. Cross section is interpolated by a polynomial in theta and used in CSB subtraction.

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting Cerenkov Center Efficiency Correction… Experiment & Data analysis Due to the gap between the cerenkov mirrors, there is an efficiency problem in the center region. #PE>1 Corr < 0.5% 1/Eff  p/p 1/Eff Position dependency of Cerenkov efficiency #PE>2 Corr ~ 2% This effect is bigger than we had in Jan05. That might be because cerenkov had been moved between the two experiments.

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting Experiment & Data analysis Cerenkov Center Efficiency Correction… Before the correctionAfter the correction

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting Data to Monte Carlo simulation comparisons… Experiment & Data analysis

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting Experiment & Data analysis Checked optics elements, magnets fields, matrix elements and no difference found from previous data. Significantly different from previous data!!! FPP was tested before ROSEN07. Would detector positions have been effected by all that weight on detector frame? Could it be because of DC offsets? Preliminary Drift Chamber Position Studies

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting Experiment & Data analysis xx yy x and y positions of drift chambers of old (Jan05) and new (Rosen07) data compared to find the amount of shift.  x_DC1=0.70cm  y_DC1=0.33 cm  x_DC2=0.45 cm  y_DC2=0.30 cm Mean = 0.34 Mean = 0.01 Center pos of Jan05 data Center pos of ROSEN07 data ROSEN07 JAN05 Preliminary Drift Chamber Position Studies

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting Preliminary Drift Chamber Position Studies Experiment & Data analysis BeforeAfter After DC position adjustment in replay: 1-Y / tar comparison gets better, 2- Y tar becomes narrower, Point target study [1% RL Carbon target]

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting 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 Peter Bosted’s model used as input model. And this data has helped in the development of this model.

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting Cross Sections (preliminary) Experiment & Data analysis

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting Experiment & Data analysis Cross Sections (preliminary)

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting And L/T Separations… Here is some preliminary L/T separations from Vahe Mamyan. Experiment & Data analysis

Ibrahim H. Albayrak, January 2009 HallC Collaboration Meeting Summary Calibrations are done. Charge symmetric background subtraction, radiative corrections and other corrections are mostly done. Some preliminary L/T separations have already been done (Vahe). Continue data analysis L/T separations Moment extractions n-p analysis Experiment & Data analysis