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Single Spin Asymmetry in Correlated Quark Model G. Musulmanbekov JINR, Dubna e-mail:genis@jinr.ru. Contents Introduction Strongly Correlated Quark Model (SCQM) Single Spin Asymmetry in hadronic reactions Collins Effect Sivers Effect Conclusions SPIN2006. Introduction.
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Single Spin Asymmetry in Correlated Quark Model G. MusulmanbekovJINR, Dubnae-mail:genis@jinr.ru Contents Introduction Strongly Correlated Quark Model (SCQM) Single Spin Asymmetry in hadronic reactions Collins Effect Sivers Effect Conclusions SPIN2006
Introduction Where does the Proton Spin come from? Spin "Crisis“: DIS experiments: ΔΣ=Δu+Δd+Δs ≪ 1 SU(6) 1 Sum rule for the nucleon spin: 1/2 =(1/2)ΔΣ(Q²)+Δg(Q²)+L(Q2)q+g • SCQM: • Total nucleon spin comes from circulating • around each of three valence quarks gluon • and quark-antiquark condensate.
(x) Vacuum fluctuations (radiation) pressure Vacuum fluctuations (radiation) pressure Vacuum polarization around single quark Quark and Gluon Condensate Attractive Force Attractive Force Strongly Correlated Quark Model (SCQM)
Constituent Quarks – Solitons Sine- Gordon (SG) equation Breather – oscillating soliton-antisoliton pair, the periodic solution of SG: The density profile of the breather: Breather solution of SG is Lorenz – invariant. Effective soliton – antisoliton potential
is the potential energy of the quark. Hamiltonian of the Quark – AntiQuark System , are the current masses of quarks, = (x)– the velocity of the quark (antiquark), is the quark–antiquark potential.
For simplicity Conjecture: where is the dynamical mass of the constituent quark and
Quark Potential inside Light Hadons I II U(x) > I – constituent quarks U(x) < II – current(relativistic) quarks
Quark Potential inside Light Hadrons Uq x Uq= 0.36tanh2(m0x)
Generalization to the 3 – quark system (baryons) _ 3 3 CMY RGB, qqq _ ( 3)Color qq
The Proton One–Quark color wave function Where are orthonormal states with i = R,G,B Nucleon color wave function
Considering each quark separatelySU(3)Color U(1) Destructive Interference of color fields Phase rotation of the quark w.f. in color space: Phase rotation in color space dressing (undressing) of the quark the gauge transformation chiral symmetry breaking (restoration) here
Spin in SCQM • Now we accept that and intersecting Echand Bchcreate around VQcirculating flow of energy, color analog of the Pointing’s vector Sch=c²Ech×Bch. Classical analog of electron spin – F.Belinfante 1939; R. Feynman 1964; H.Ohanian 1986; J. Higbie 1988. 2. Circulating flow of energy carrying along with it hadronic matter is associated with hadronic matter current. 3. Total angular momentum created by this Pointing’s vector is associated with the total spin angular momentum of the constituent quark.
4. Quark oscillations lead to changing of the values of Echand Bch : at the origin of oscillations they are concentrated in a small space region around VQ. As a result hadronic current is concentrated on a narrow shell with small radius. 5. Quark spins are perpendicular to the plane of oscillation. 6. Quark spin module is conserved during oscillation: Analogue from hydrodynamics Helmholtz laws for velocity field ((∂ξ)/(∂t))+∇×(ξ×v)=0, ξ=∇×v, ∇⋅v=0, lead to
1.Mass of Consituent Quark Parameters of SCQM 2.Maximal Displacement of Quarks:xmax=0.64 fm, 3.Constituent quark sizes(parameters of gaussian distribution): x,y=0.24 fm, z =0.12 fm Parameters 2 and 3 are derived from the calculations of Inelastic Overlap Function (IOF) and in and pp – collisions.
Summary on SCQM • Quarks and gluons inside hadrons are strongly correlated; • Constituent quarks are identical to vortical solitons. • Hadronic matter distribution inside hadrons is fluctuating quantity resulting in interplay between constituent and current quarks. • Hadronic matter distribution inside the nucleon is deformed; it is oblate in relation to the spin direction.
Single Spin Asymmetry in proton – proton collisions • In the factorized parton model where
Geometrical viewof possible quark configurations inside colliding protons at the instant of collision
Geometrical viewof possible quark configurations inside colliding protons at the instant of collision
Calculation of cross section with the use of Inelastic Overlap Fuction Monte-Carlo simulation of inelastic events using modified Heisenberg picture: + energy – momentum conservation
Calculationsof Collins Effect PureCollinsEffect: leading quark is a spectator
“Sivers” Effect in SSA Single Spin Asymmetries Spin-up polarized quark - vortex Chou & Yang 1976 Hadronic matter current distributions inside polarized hadrons and nuclei
Collins & “Sivers” Effect in SSA Single Spin Asymmetries
Experiments with Polarized Protons Double Spin Asymmetries Anti-parallel Spins Parallel Spins