GDH Analysis Meeting
December 06, 2002



    Karl Slifer discussed his work on target thickness and cross sections:
        Karl looked at the thickness along the beam line before and after scattering.
    He discovered that Be window was 15 mil, and Ed had never used a 10 mil
    window.  By comparing previous values with Karl's thickness values, Karl
    found that the after scattering values are similar, but the before scattering
    thickness increased by 30%.

        Karl gave an overview of the procedure to calculate the Born cross
    section from the raw cross section.  He also discussed the calculation of
    the errors.

        A spectrometer comparison for Jin, a cell for which the thickness is known
    well, shows that  the difference between the cross sections is only 2.5 to 5%.
    But for Armageddon the thickness is not known well, and the difference in the
    cross sections is much larger.

        Karl will check the effect of the radiation length increase due to the 15 mil
    Be window and rerun the  cross sections with the correct RL.  He will soon
    start the 3He GDH analysis.

    The collaboration will discuss the second paper on structure functions
     next week on Friday, December 13, 2002, since Zein-Eddine Meziani
    could not make to the meeting:
 

    Nilanga Liyanage discussed the third paper on twist expansions/duality:
        Nilanga will have more results for the next meeting.

     The collaboration discussed upcoming and new experiments:
        Doug Higinbotham talked about the approved 3He(e,e'd) experiment.  The
    experiment will measure the Ax and Az asymmetries to pin down the error
    from the nuclear polarizations.  Big Bite will be used 1 meter from the target.

        Gordon Cates discussed the preparations for GE at high Q2.   Magnetic field
    calculations are being done to find a way to compensate for the gradient field from
    Big Bite.  For the experiment the laser hut and current scattering chamber will not
    be used.  To compensate for the gradient, a new idea is being considered to replace
    the coils with plates and to wrap the coils around the plates.

         Xiaodong Jiang, discussed a new proposal that will be presented at the next
    PAC.  The proposal will measure the transversity of the neutron.  The experiment
    will use Big Bite to detect electrons, and the HRS to detect charged pions.  Big Bite
    will be located 1.5 meters from the target, where gradients are not expected to be
    a large problem.

    JP Chen discussed conferences for 2003:
     JP suggested that members of the collaboration think about possible
    conferences to which they would like to go and to let him know of any
    conferences not included on the list.  JP will send out an updated list, when
    he gets all the information together.
 

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