( ) ô ö .04.16 - ž
- : - (SSA) (TMD) (GPDs), : HERMES Hall B- : - (SIDIS) , :
, , - , TMD-, : : , (QCD) : Hermes- CLAS- -3 :
, - [1,2] [3,4] , [5, 6] ,  , - [1,9], ` , - (DVCS) , - (DVMP) :
, (GPDs) , (TMDs), JLab 12 - : , GPD TMD JLab-, JLab- (PAC) , : JLab- CLAS12 , ` , , , :
In this dissertation we present a series of measurements of spin and azimuthal asymmetries in electroproduction of final state particles in semi-inclusive hard exclusive processes.
Theáástudiesááofááspinááandááspin azimuthal asymmetries in electroproduction providing access to differentá Transverse Momentum Dependent (TMD) partonic distributions and á aGeneralized Parton Distributions ( GPDs)á areá aá core subjectsá of this dissertation,á andá theyá are based oná theá data fromá the HERMESá collaborationá andá fourá experimentsá carriedá outá iná Hallá Bá at Jeffersoná Laboratory.
MeasuredáásingleááspinááasymmetriesááinááelectroproductionááofáápionsááinááSIDISááindicateááthatááthe correlatiţnsá ofá the transverse spin of quarks with their transverse momentum leadáátoááobservableááspinááand azimuthal asymmetries. The measurement of the siná2 momentsá áin particular provides directá information on spin-orbit correlations by measuring the leading twist TMDs related to the interference between states with different orbital momenta. The PT-dependence of the double spin asymmetries provide additional information on the avor and polarization dependence ofá transverse momentum dependence of helicity distributions of quarks, providing complementary to SSA measurements access to spin-orbit correlations. The siná and siná2 moments have been studied toá probeá he underlying T-odd distribution and fragmentation functions. Signicant experimental, phenomenological and theoretical efforts have been made to understand the SSAs in QCD at twist-2 and beyond. Parton model analysis of sub-leading single-spin asymmetriesá observed at HERMESá andá CLASá ledá toá introductioná ofá a completeá setááofá twist-3á distributionááfunctions.
Mainááresultsááweááwilláádefendááinááthisáádissertationááinclude:áárstááobservation of polarized target SSAs in electroproductioná ofá chargedá [1,áá2] and neutral [3,áá4] pionsááiná semi-inclusiveááDIS, rstá observationá ofá polarizedá beamá SSAs in electroproductioná ofá positiveá pionsáá[5,áá6]á andá rstá signicantá measurementsá ofá SSAsá forá negativeáá,ááandá neutralááá pionsá iná semi-inclusiveááDIS,áárst measurementááofááKotzinian-Muldersá asymmetryáá[1,áá9],á rstá measurementsááofá transverseá momentum dependencesá ofáádoubleá spiná asymmetriesá iná SIDISá ,á rstá observationá ofá polarizedá targetá SSAsá in hardá exclusiveá productioná ofá photonsá (DVCS),á rstá observationá ofá polarized beamá SSAsá in hard exclusiveáproductionáofá pionsá . Transverseááspaceáádistributionsááofáápartons,ááencodedááinááGeneralizedááPartonááDistributions,ááand transverseá momentumá dependentá distributions,á encoded in Transverse Momentum Distributions, haveá beená widely árecognizedá asá key objectivesá ofá theá JLabá 12á GeVá upgradeáand aá drivingá forceá behindá construction of the Electron Ion Collider. Several proposals have been alreadyá approved by the JLab PAC to study GPDs and TMDs at JLab12 and were áawarded the highest physics rating.
Using the upgraded JLab electron beam and CLAS12 detector at its maximum luminosity future experiments will take full advantage of the unique combination of wide kinematic coverage, high beam intensity (luminosity), high energy, high polarization, and advanced detection capabilities to extend presented measurements and study the transverse momentum and spin correlations in hard scattering ináexclusive and semi-inclusive DIS with unprecedented precision.