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- : - (SSA) (TMD) (GPDs), : HERMES Hall B- : - (SIDIS) , :

[9], , - , TMD-, : : , (QCD) : Hermes- CLAS- -3 :

, - [1,2] [3,4] , [5, 6] [7], [8] , - [1,9], ` [9], - (DVCS) [10], - (DVMP) [11]:

, (GPDs) , (TMDs), JLab 12 - : , GPD TMD JLab-, JLab- (PAC) , : JLab- CLAS12 , ` , , , :

StudiesoftheSpinandAzimuthalAsymmetriesin Electroproduction


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.

Thestudiesofspinandspin azimuthal asymmetries in electroproduction providing access to different Transverse Momentum Dependent (TMD) partonic distributions and aGeneralized Parton Distributions ( GPDs) are a core subjects of this dissertation, and they are based on the data from the HERMES collaboration and four experiments carried out in Hall B at Jefferson Laboratory.

MeasuredsinglespinasymmetriesinelectroproductionofpionsinSIDISindicatethatthe correlatins of the transverse spin of quarks with their transverse momentum leadtoobservablespinand azimuthal asymmetries. The measurement of the sin2 moments [9]in particular provides direct 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 of transverse momentum dependence of helicity distributions of quarks, providing complementary to SSA measurements access to spin-orbit correlations. The sin and sin2 moments have been studied to probe 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 asymmetries observed at HERMES and CLAS led to introduction of a complete setof twist-3 distributionfunctions.

Mainresultswewilldefendinthisdissertationinclude:rstobservation of polarized target SSAs in electroproduction of charged [1,2] and neutral [3,4] pionsin semi-inclusiveDIS, rst observation of polarized beam SSAs in electroproduction of positive pions[5,6] and rst signicant measurements of SSAs for negative[7],and neutral[8] pions in semi-inclusiveDIS,rst measurementofKotzinian-Mulders asymmetry[1,9], rst measurementsof transverse momentum dependences ofdouble spin asymmetries in SIDIS [9], rst observation of polarized target SSAs in hard exclusive production of photons (DVCS)[10], rst observation of polarized beam SSAs in hard exclusiveproductionof pions [11]. Transversespacedistributionsofpartons,encodedinGeneralizedPartonDistributions,and transverse momentum dependent distributions, encoded in Transverse Momentum Distributions, have been widely recognized as key objectives of the JLab 12 GeV upgradeand a driving force behind construction of the Electron Ion Collider. Several proposals have been already approved by the JLab PAC to study GPDs and TMDs at JLab12 and were awarded 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 inexclusive and semi-inclusive DIS with unprecedented precision.

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