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account their RG evolution. As a result, we extract the value of the singlet axial charge a0(1 GeV 2 ) = 0.33 ± 0.05. This value is very close to the corresponding COMPASS 0.35 ± 0.06 [7] and HERMES 0.35 ± 0.06 [8] results. Table 1: Combined fit results of the proton Γ p 1 (Q2 ) data (elastic contribution excluded). APT fit results a0 AP T and μ4,6,8 (at the scale Q2 0 =1GeV2 ) are given without and with taking into account the RG Q2-evolution of a0(Q2 AP T ) and μ4 (Q2 ). The minimal borders of fitting domains in Q2 are settled from the ad hoc restriction χ2 � 1 and monotonous behavior of the resulting fitted curves. Method Q 2 min, GeV 2 a0 μ4/M 2 μ6/M 4 μ8/M 6 0.59 0.33(3) −0.050(4) 0 0 PT 0.35 0.43(5) −0.087(9) 0.024(5) 0 0.29 0.37(5) −0.060(15) -0.001(8) 0.006(5) 0.47 0.35(4) −0.054(4) 0 0 APT 0.17 0.39(3) −0.069(4) 0.0081(8) 0 (no evolution) 0.10 0.43(3) −0.078(4) 0.0132(9) −0.0007(5) 0.47 0.33(4) −0.051(4) 0 0 APT 0.17 0.31(3) −0.059(4) 0.0098(8) 0 (with evolution) 0.10 0.32(4) −0.065(4) 0.0146(9) −0.0006(5) In order to see how the Q2 min scale and fit results for the μ-terms change with varying ΛQCD, we have performed three different NLO fits with ΛQCD = 300, 400, 500 MeV. It turns out that the term μ4 is quite sensitive to the Landau singularity position, and its value noticeably increases with increasing ΛQCD. The APT is free of such a problem thus providing a reliable tool of investigating the behavior of higher twist terms extracted directly from the low-energy data. In the APT approach the convergence of both the higher orders and higher twist series is much better. In both the nonsinglet and singlet case, while the twist-4 term happened to be larger in magnitude in the APT than in the conventional PT, the subsequent terms are essentially smaller and quickly decreasing (as the APT absorbs some part of nonperturbative dynamics described by higher twists). This is the main reason of the shift of the pQCD frontier to lower Q values. A satisfactory description of the proton spin sum rule data down to Q ∼ ΛQCD � 350 MeV was achieved (see Fig. 1b). In a sense, this could be natural if the main reason of such a success was the disappearance of unphysical singularities. Note that the data at very low Q ∼ ΛQCD are usually dropped from the analysis of a0 and higher-twist term in the standard PT analysis because of Landau singularities. The compatibility of our results for a0 and previous results [7, 8] demonstrates the universality of the nucleon spin structure at large and low Q2 scales. This work was partially supported by RFBR grants 07-02-91557, 08-01-00686, 08- 02-00896-a, and 09-02-66732, the JINR-Belorussian Grant (contract F08D-001) and RF Scientific School grant 1027.2008.2. References [1] S.E. Kuhn, J.P. Chen and E. Leader, Prog. Part. Nucl. Phys. 63 (2009) 1. 100
[2] Y. Prok et al. [CLAS Collaboration], Phys. Lett. B672 (2009) 12; see also talk at this conference. [3] R.S. Pasechnik, D.V. Shirkov and O.V. Teryaev, Phys. Rev. D78 (2008) 071902. [4] D.V. Shirkov and I.L. Solovtsov, Phys. Rev. Lett. 79 (1997) 1209. [5] R.S. Pasechnik, D.V. Shirkov, O.V. Teryaev, O.P. Solovtsova and V.L. Khandramai, arXiv:0911.3297 [hep-ph]. [6] Yu.A. Simonov, Phys. Atom. Nucl. 65, 135 (2002). [7] V.Y. Alexakhin et al. [COMPASS Collaboration], Phys. Lett. B647 (2007) 8. [8] A. Airapetian et al. [HERMES Collaboration], Phys. Rev. D75 (2007) 012007. [9] J. Soffer and O. Teryaev, Phys. Rev. Lett. 70, 3373 (1993); Phys. Rev. D70, 116004 (2004). 101
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XIII Advanced Research Workshop on
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ã�� [539.12.01 + 539.12 ... 14
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Analytic perturbation theory and pr
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Measurements of GEp/GMp to high Q 2
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WELCOME ADDRESS Alexei Sissakian Di
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he joined the group of prof. Przemy
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proton. Dividing these 90 ◦ cm p-
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p-p scattering angle fixed at exact
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tuning for each ring. The Workshop
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was only about 10 5 per second, but
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[10] E.F. Parker et al., Phys. Rev.
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MICROSCOPIC STERN-GERLACH EFFECT AN
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DeGrand-Miettinen model predicted P
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TOWARDS STUDY OF LIGHT SCALAR MESON
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104xdBR(φ--> π η 0 -1 γ )/dm, G
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RECURSIVE FRAGMENTATION MODEL WITH
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Figure 2: String decaying into pseu
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pT -distributions in the quark frag
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4 Inclusion of spin-1 mesons For a
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CONSTITUENT QUARK REST ENERGY AND W
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〈r 2 ch 〉≈1fm2 . Now with Eqs
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TOWARDS A MODEL INDEPENDENT DETERMI
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Common for the difference cross sec
Page 51 and 52: TRANSVERSITY GPDs FROM γN → πρ
Page 53 and 54: The scattering amplitude of the pro
Page 55 and 56: INFRARED PROPERTIES OF THE SPIN STR
Page 57 and 58: 5 Acknowledgement B.I. Ermolaev is
Page 59 and 60: We shall call this model the “sec
Page 61 and 62: y f ν V = f l V = f u V = f d gz V
Page 63 and 64: 2. We remind, that the celebrated G
Page 65 and 66: of the resonance A, θV � 39 o .
Page 67 and 68: • Right-handed EW currents. The c
Page 69 and 70: pesum- (p Entries 0 + pe)-(p-pe) Me
Page 71 and 72: CROSS SECTIONS AND SPIN ASYMMETRIES
Page 73 and 74: R(ρ) 5 4 3 2 1 0 2 3 4 5 6 7 8 9 1
Page 75 and 76: TWO-PHOTON EXCHANGE IN ELASTIC ELEC
Page 77 and 78: and depend on three parameters : fN
Page 79 and 80: O(αs) SPIN EFFECTS IN e + e −
Page 81 and 82: 3 Polarization results for mq → 0
Page 83 and 84: Since one has (↑↓) pc Born =(
Page 85 and 86: Figure 1: A typical lowest order Fe
Page 87 and 88: sin φ S (π + ) A UT 1.0 0.8 0.6 0
Page 89 and 90: form the agreement with these data
Page 91 and 92: in settling this dynamical issue. G
Page 93 and 94: SPIN CORRELATIONS OF THE ELECTRON A
Page 95 and 96: the two-photon system equaling 1).
Page 97 and 98: ANOTHER NEW TRACE FORMULA FOR THE C
Page 99 and 100: Compare the gain of time and effort
Page 101: where the triplet and octet axial c
Page 105 and 106: Melosh rotations which boost the re
Page 107 and 108: ky �GeV� 0.4 0.2 0.0 �0.2 �
Page 109 and 110: [2] B. Pasquini, and S. Boffi, Phys
Page 111 and 112: The appearance of both |+〉 and |
Page 113 and 114: 2.2 Intrinsic Transverse Motion Qua
Page 115 and 116: are still complex: for a given corr
Page 117 and 118: This last is required to complete t
Page 119 and 120: [16] P.G. Ratcliffe and O.V. Teryae
Page 121 and 122: Figure 1: a)[left] μpG p E /Gp M (
Page 123 and 124: 4 Conclusion We introduced a simple
Page 125 and 126: √ δΔq8 x for Δq8 and γΔGx fo
Page 127 and 128: understanding of polarized light qu
Page 129 and 130: They are inverse powers of Q 2 kine
Page 131 and 132: accounts approximately for the TM a
Page 133 and 134: POTENTIAL FOR A NEW MUON g-2 EXPERI
Page 135 and 136: When the momentum increases (p >p0)
Page 137 and 138: EVOLUTION EQUATIONS FOR TRUNCATED M
Page 139 and 140: 4 Perspectives Evolution equations
Page 141 and 142: NEW DEVELOPMENTS IN THE QUANTUM STA
Page 143 and 144: statistical approach compared to th
Page 145 and 146: POLARIZED HADRON STRUCTURE IN THE V
Page 147 and 148: g 3 A =Δuv(Q 2 ) − Δdv(Q 2 ), g
Page 149 and 150: AXIAL ANOMALIES, NUCLEON SPIN STRUC
Page 151 and 152: 3. Vector current of strange quarks
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ORBITAL MOMENTUM EFFECTS DUE TO A L
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The elastic scattering S-matrix in
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IDENTIFICATION OF EXTRA NEUTRAL GAU
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for final l + l − events (l = μ,
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QUARK INTRINSIC MOTION AND THE LINK
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where wP = − m 2M 2 −p1 cos ω
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where g q 2x − ξ 1(x, pT )= πM2
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EXPERIMENTAL RESULTS
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01 00 11 01 01 01 00 11 01 01 01 00
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where C1, C2 and A1 - signals from
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Figure 1: Layout of experiment targ
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According to requirements of the de
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Electron energy is measured at ATLA
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Fig. 2 shows the results of the lon
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e γ* e’ x+ ξ x− ξ A A’ e e
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cos 0φ C A φ cos C A cos 2φ C A
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5 Summary HERMES has measured signi
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(1.205 ± 0.0012) GeV/c, 10 10 p/s,
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was done in the interval ”−t”
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If we admit a non-zero quark transv
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which is trivial in collinear LO ap
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In figure 3 the expected errors on
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[12] A. V. Efremov and O. V. Teryae
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Figure 1: The COMPASS spectrometer.
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Comparing this formula to the inclu
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Figure 5: Comparison of COMPASS inc
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[9] B. Adeva et al. (SMC Coll.), Ph
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q T sin( φ-φ ) M AUT 0.14 0.12 0.
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proton beam is planned. References
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Run Year √ s (GeV) Polarization R
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ackground fraction, and asymmetry i
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At √ s = 200 GeV, ALL(pp → π
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[6] D. de Florian, W. Vogelsang, an
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higher energies, where the cross se
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Figure 3: The experimental results
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kinematic range to low values of Bj
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3 Semi-Inclusive DIS Collins and Si
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Unpolarized target asymmetries. The
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4 Summary Since the end of data-tak
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polarization as well as a construct
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Finally the COMPASS reconstruction
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tained in the NLO QCD approximation
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with only modern NN potential are r
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(a) (b) Figure 3: (a) T20 data take
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of electroproduction from polarized
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As is seen in Fig. 1 values of the
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SEMI-INCLUSIVE DIS AND TRANSVERSE M
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The yellow band in Fig. 1 is the re
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At leading twist, a third asymmetry
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THE COMPLETION OF SINGLE-SPIN ASYMM
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A N , % 30 20 10 0 0 0.2 0.4 0.6 0.
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Unexpectedly large single spin asym
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THE GENERALIZED PARTON DISTRIBUTION
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, E) H ~ (H, I Im C 5 4 3 2 1 Q = 1
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Reducing to a common denominator (
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LAMBDA PHYSICS AT HERMES S. Belosto
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analysis was carried out reconstruc
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SPIN PHYSICS AT NICA A. Nagaytsev J
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original software packages (MC simu
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MEASUREMENTS OF TRANSVERSE SPIN EFF
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to “near-side” and “away-side
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THE FIRST STAGE OF POLARIZATION PRO
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In paper [12] the study was made of
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emphasis to increase the statistics
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Table 2: The parameters of the main
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POLARIZATION MEASUREMENTS IN PHOTOP
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With a polarized electron beam inci
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Figure 3: Preliminary helicity asym
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INVESTIGATION OF DP-ELASTIC SCATTER
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framework with the use of deuteron
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SPIN PHYSICS WITH CLAS Y. Prok 12,
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1.3 Flavor Decomposition of the Hel
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Γ p 1 0.15 0.125 0.1 0.075 0.05 0.
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The upcoming energy upgrade of Jeff
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y the nearly 1000 combined citation
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� R = −Pt/Pl τ(1 + ε)/2ε; he
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4 Results of GEp-III Experiment In
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6 Theoretical Developments The earl
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lz = 0 (along the direction of the
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models have recently been challenge
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[32] Chung P. L. and F. Coester, Ph
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48 ± 3% for two beams. The proton
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is constant with cos θ∗ , as exp
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In summary, we made measurements on
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angle between the direction of the
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The sensitivity of the data to the
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COMPASS could be converted into a f
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3.1.2 Beam charge and spin asymmetr
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contributions enter only beyond lea
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References [1] D. Mueller et al, Fo
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l’ l p q p h H (z) 1 h (x) 1 l l
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3. Data selection. The data selecti
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φ sin3 a 0.06 0.04 0.02 0 -0.02 -0
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TRANSVERSE SPIN AND MOMENTUM EFFECT
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model. Both the cos φh and the cos
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D cos φ A 0 -0.1 -0.2 -0.3 + h -2
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4.3 The Sivers asymmetry According
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[3] A. Airapetian et al. [HERMES co
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2. Delta-Sigma Experimental Set-up.
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6. Estimate of the count rate in tr
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2 Analysis Formalism Spin-dependent
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The MC production comprises three s
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6 High pT hadron pair analysis for
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[2] V. Y. Alexakhin et al. [COMPASS
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2 Towards polarized Antiprotons For
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4 Spin-Filtering Experiments at COS
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to test the theoretical models of t
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C1 C2 π CH1,2 CH3,4 CH5,6 111 000
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not even resemble the data behavior
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to the slope of the Rosenbluth plot
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The differential cross section of t
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with zero for all mass ranges, with
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more precise and dedicated measurem
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oth types of experiment results are
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is recorded, a good particle identi
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error of the extracted asymmetries
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2.6 Summary and Outlook The first d
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386
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PROTON BEAM POLARIZATION MEASUREMEN
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N A 0.06 0.05 0.04 0.03 0.02 0.01 0
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Intensity profile (arb. units) 1 0.
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[4] H. Okada et al., Proc. of the 1
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The amplitudes of the signals and t
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The following results has been obta
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interaction vanishes and a single Z
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an amorphous NH3 for low and high,
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and depends on a choice of � ℓ1
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3 The conditions for transparent sp
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where angles α and β are defined
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forward angles, where vector Ay and
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espectively. The open symbols repre
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RF dipole (transverse B): εBdl = 1
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i PV / PV i PV / PV 1 0.5 0 -0.5 -1
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The energies of the states Ψ1 −
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field P ≈ +1. If we add the trans
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econstruction provide more accurate
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y detector saturation from pC colli
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2 �p+ 8 He analyzing power measur
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3.3 Effect of valence neutrons on s
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i.e. n0(θ +2π) =n0(θ) . There ar
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w and ˙ɛ. For example, we use par
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436
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REGULARIZATION OF SOURCE OF THE KER
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The corresponding phase transition
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ABOUT SPIN PARTICLE SOLUTION IN BOR
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where the functions fi(s, η) must
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SPINDYNAMICS I.B. Pestov JINR, 1419
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State of hadron matter is defined t
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REMARK ON SPIN PRECESSION FORMULAE
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It is easy to see that for a (massi
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DYNAMICS OF SPIN IN NONSTATIC SPACE
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Schwinger gauge. Probably for the f
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DSPIN-09 WORKSHOP SUMMARY Jacques S
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to some preliminary results reporte
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A new measurement of the polarizati
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new NLO QCD parametrization of the
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Name (Institution, Town, Country) E
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References - Bogoliubov Laboratory of Theoretical Physics - JINR

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