[Gdh_lowq2] Abstract for PANIC 2011

[Marco Ripani]

... or better "...composite nucleon undergoes a transition to all 
possible...."
Marco

Marco Ripani wrote:
> Hi Sarah,
> your abstract looks fine to me, except that I would modify one 
> sentence as follows:
> "the spin structure functions g1 and g2, fundamental spin observables 
> which parameterize the way a polarized composite nucleon fragments 
> into all possible final states". I think speaking in terms of 
> deviation from point-like behavior recalls more the elastic form 
> factors, rather than the inclusive structure functions.
>
> Regards
> Marco
>
> Sarah Phillips wrote:
>> Dear EG4 collaborators,
>>
>>        I would like to submit the following abstract for PANIC 2011 (see
>> http://web.mit.edu/panic11/index.html).  Please let me know if you have
>> comments.  The abstract deadline is tomorrow, so please do not delay in
>> sending your comments!  I apologize for the last-minute nature of this
>> request, and thank you for your time.
>>
>> With Regards,
>>
>> Sarah
>>
>>
>>
>> Nucleon Spin Structure and the JLab CLAS EG4 Experiment
>>
>>
>> Our picture of the nucleon is not complete without a thorough
>> understanding of the spin structure of the nucleon.  One way to access
>> spin information is by measuring the spin structure functions g1 and g2,
>> which are fundamental spin observables which characterize the 
>> deviation of
>> the nucleon's spin-dependent properties from point-like behavior.
>> Knowledge of g1 at low Q^2 would provide tests of chiral perturbation
>> theory predictions in the resonance region.  However, data on g1 for the
>> proton at very low Q^2 are lacking.  The CLAS EG4 experiment was 
>> performed
>> at Jefferson Lab to determine the generalized GDH sum for the proton and
>> the neutron at very low Q^2 from 0.015 to 0.5 (GeV/c)^2.   The 
>> experiment
>> used Hall B's CLAS (CEBAF Large Acceptance Spectrometer) to perform a
>> measurement of the helicity-dependent inclusive cross section 
>> differences
>> for the scattering of polarized electrons from polarized protons and
>> deuterons in solid polarized NH3 and ND3 targets.  From this absolute
>> polarized cross section measurement, we will be able to extract the
>> inclusive spin structure function g1 for the proton and the 
>> deuteron.  In
>> addition to the spin structure functions that can be obtained from the
>> inclusive measurement, the same data can be used to extract pion
>> electroproduction asymmetries in the resonance region through the 
>> analysis
>> of exclusive channels.  Upon completion of the analysis, the inclusive
>> results will give a good test of chiral perturbation theory predictions.
>> An overview of the EG4 experiment will be given, as well as preliminary
>> results for the inclusive and exclusive analyses.
>>
>>
>>
>>
>> _______________________________________________
>> Gdh_lowq2 mailing list
>> Gdh_lowq2 at jlab.org
>> https://mailman.jlab.org/mailman/listinfo/gdh_lowq2
>

-- 

Marco Ripani
Senior Scientist, Istituto Nazionale di Fisica Nucleare - Genova
Address:
INFN
Via Dodecaneso 33
16146 GENOVA - ITALY
tel./fax 39-010-3536458
cell. 39-328-2191138
Jlab office room F244
tel. 1-757-269-7266  fax 1-757-269-6273
E-Mail: ripani at ge.infn.it