Vahe Mamyan, Hall-C collaboration meeting, January Data Analysis of F2 and R in Deuterium and Nuclei  Physics  Experiment Setup  HMS Detectors  Calibrations  Data Analysis  Cross Section calculation Vahe Mamyan Ibrahim Albayrak Hampton University

Vahe Mamyan, January 2008 Hall C Users Meeting Measurement of R =  L /  T on Deuterium in the Nucleon Resonance Region. Physics

Vahe Mamyan, January 2008 Hall C Users Meeting Inclusive Scattering Inclusive e + d  e + X Scattering Where:  = flux of transversely polarized virtual photons  = relative longitudinal flux longitudinalTransverse mIxEdmIxEdmIxEdmIxEd Rosenbluth Separation Technique :

Vahe Mamyan, January 2008 Hall C Users Meeting JAN05 ROSEN07 New data with high Q^2 above 3 And new epsilon points for LT separation

Vahe Mamyan, January 2008 Hall C Users Meeting Physics F L, F 1, F 2 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

Vahe Mamyan, January 2008 Hall C Users Meeting Deuteron, Neutron, and non-singlet L/T Moments - Can extract low Q 2 neutron moments with minimal uncertainties from nuclear corrections! - Neutron L/T SFs can be extracted using proton and deuteron L/T SFs combined with BoNuS neutron cross sections. - Below x < 0.7 is the safe region to extract neutron moments

Vahe Mamyan, January 2008 Hall C Users Meeting 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-singlet At moderate x (~ 0.3), singlet comparable to non-singlet 1

Vahe Mamyan, January 2008 Hall C Users Meeting ∫(F d – 2F p )dx yields non-singlet distribution 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 (F L ) Need to pin down non-singlet (n-p) to extract singlet (F L ) OPEN QUESTION IN QCD: Do we have valence, or intrinsic, glue? Need F L d – 2F L p OPEN QUESTION IN QCD: Do we have valence, or intrinsic, glue? Need F L d – 2F L p “..highly precise deuteron data - due to the above aspects - “..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

Vahe Mamyan, January 2008 Hall C Users Meeting Moments of the Structure Functions M n (Q 2 ) = ∫ dx x n-2 F(x,Q 2 ) Calculated on the lattice at Q 2 = 4 GeV 2 Well understood in QCD Operator Product Expansion 0 1

Vahe Mamyan, January 2008 Hall C Users Meeting Preliminary cross section for Deuterium…

Vahe Mamyan, January 2008 Hall C Users Meeting Data to Monte Carlo simulation comparisons…

Vahe Mamyan, January 2008 Hall C Users Meeting In Conclusion… No L/T separated resonance region (large x) data on deuterium currently Impossible to extract high precision moments Compare to lattice F L to access singlet

Vahe Mamyan, January 2008 Hall C Users Meeting Experimental Setup e- e´- Electron Beam Target Scattering Chamber HMS X Detector Hut

Vahe Mamyan, January 2008 Hall C Users Meeting HMS Detectors Drift Chambers, Horizontal and vertical Vertically and Horizontally segmented hodoscopes Gas Cerenkov Electro-magnetic calorimeter

Vahe Mamyan, January 2008 Hall C Users Meeting 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

Vahe Mamyan, January 2008 Hall C Users Meeting BCM calibration

Vahe Mamyan, January 2008 Hall C Users Meeting BCM calibration-cont.

Vahe Mamyan, January 2008 Hall C Users Meeting Calorimeter calibration

Vahe Mamyan, January 2008 Hall C Users Meeting Gas Cerenkov calibration

Vahe Mamyan, January 2008 Hall C Users Meeting Data Analysis Particle identification Background subtraction Acceptance calculation Corrections Cross section calculation

Vahe Mamyan, January 2008 Hall C Users Meeting 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

Vahe Mamyan, January 2008 Hall C Users Meeting Background subtraction Electrons produced from charge-symmetric π o 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.

Vahe Mamyan, January 2008 Hall C Users Meeting Acceptance calculation Acceptance is calculated for each Θ-W 2 bin. Number of Θ bins is fixed, 20 bins. Size of the W bin is 0.04 GeV 2.

Vahe Mamyan, January 2008 Hall C Users Meeting Corrections Target boiling. Radiative corrections.

Vahe Mamyan, January 2008 Hall C Users Meeting Cross Section calculation Measured CS Rad. corrected CS Bin correction factor Bin corrected cross section

Vahe Mamyan, January 2008 Hall C Users Meeting Cross Section No charge symmetric background subtracted

Vahe Mamyan, January 2008 Hall C Users Meeting Summary Calibrations are mostly done. Implement charge symmetric background subtraction. Continue data analysis