References - Bogoliubov Laboratory of Theoretical Physics - JINR

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of electroproduction from polarized targets is richer than that for polarized lepton beams and unpolarized targets, and the formalism was generalized for the case of polarized targets. Recently a new general formalism for the description of vector-meson SDMEs was proposed in [3]. From the symmetry properties [1–3] of the helicity amplitudes it follows that there are 18 independent amplitudes. Since the SDMEs depend on ratios of these amplitudes, there are 34 independent real parameters needed to determine all the SDMEs. However the number of SDMEs for a given measurement can exceed 34 as, for example, in the case of the 45 [3] SDMEs observable from electroproduction from a transversely polarized target with an unpolarized lepton beam. This means that the SDMEs themselves are not independent and amplitude ratios Ai provide a more economic basis for fitting the angular distributions of the decay particles. The hierarchy of amplitudes established at HERMES kinematics [4], namely |T00| 2 ∼|T11| 2 ≫|U11| 2 > |T01| 2 ≫|T10| 2 ∼|T1−1| 2 , (2) permits one to reduce the number of essential free amplitude ratios to 5: A1 =Re(T11/T00), A2 =Im(T11/T00), A3 =Re(T01/T00), A4 =Im(T01/T00), and A9 = |U11/T00|. The ratios A5 − A8 are found to be very small, where A5 =Re(T10/T00), A6 =Im(T10/T00), A7 =Re(T1−1/T00), A8 =Im(T1−1/T00). The quantities TλV λγ are a shorthand notation for the amplitudes TλV 1 1 λγ 2 2 for natural-parity exchange (NPE) without nucleon spin flip; | 2 + the amplitude of unnatural-parity exchange (UPE) is UλV νN λγλN and |U11| 2 = |U 1 1 2 |U 1− 1 2 1 1 2 | 2 . These NPE and UPE amplitudes are related to helicity amplitudes FλV νN λγλN by the equations [1–3] TλV νN λγλN =(FλV νN λγλN +(−1)λV −λγ F−λV νN −λγλN )/2, UλV νN λγλN = )/2. In Regge phenomenology, the NPE amplitudes (FλV νN λγλN − (−1)λV −λγF−λV νN −λγλN correspond to exchanges of reggeons of natural parity with P =(−1) J (Pomeron, ρ, f2, a2, ...), whereas exchanges of reggeons of unnatural parity with P = −(−1) J (π, a1, b1, ...) contribute to the UPE amplitudes. 2 Selection of Exclusive Vector Meson Events The ρ 0 and φ events used for the SDME analayis were produced in DIS of longitudinally polarized electrons and positrons with an energy 27.57 GeV from unpolarized hydrogen and deuterium targets; the ω events were collected from DIS with a transversely polarized proton and unpolarized beam. The scattered electron (positron) and particles from the decays ρ 0 → π + π − , φ → K + K − , ω → π + π − π 0 (π 0 → 2γ) were detected and identified by the HERMES spectrometer [5]. In the period 1996-2000 particles were identified using a threshold Čerenkov detector, lead glass electromagnetic calorimeter and preshower detector; since 2000 a dual-radiator RICH detector [6] replaced the threshold detector. The constraints 0.6
subtracted using simulated events generated by PYTHIA. The fraction of semi-inclusive DIS events for the entire kinematic region was found to be 8% for ρ 0 ,1.6%forφ, and 29% for ω mesons. The SDMEs were considered as free parameters in fitting the angular distributions of scattered leptons and decay hadrons using the formalism of Ref. [1]. The maximum likelihood method was used to determine the best fit with uncertainty calculations being performed by MINUIT (see details in [4]). 3 Spin Density Matrix Elements and Azimuthal Target Spin Asymmetry The SDMEs for ρ 0 and φ mesons extracted for the entire kinematic region 1
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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
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TRANSVERSITY GPDs FROM γN → πρ
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The scattering amplitude of the pro
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INFRARED PROPERTIES OF THE SPIN STR
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5 Acknowledgement B.I. Ermolaev is
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We shall call this model the “sec
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y f ν V = f l V = f u V = f d gz V
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2. We remind, that the celebrated G
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of the resonance A, θV � 39 o .
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• Right-handed EW currents. The c
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pesum- (p Entries 0 + pe)-(p-pe) Me
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CROSS SECTIONS AND SPIN ASYMMETRIES
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R(ρ) 5 4 3 2 1 0 2 3 4 5 6 7 8 9 1
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TWO-PHOTON EXCHANGE IN ELASTIC ELEC
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and depend on three parameters : fN
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O(αs) SPIN EFFECTS IN e + e −
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3 Polarization results for mq → 0
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Since one has (↑↓) pc Born =(
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Figure 1: A typical lowest order Fe
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sin φ S (π + ) A UT 1.0 0.8 0.6 0
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form the agreement with these data
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in settling this dynamical issue. G
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SPIN CORRELATIONS OF THE ELECTRON A
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the two-photon system equaling 1).
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ANOTHER NEW TRACE FORMULA FOR THE C
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Compare the gain of time and effort
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where the triplet and octet axial c
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[2] Y. Prok et al. [CLAS Collaborat
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Melosh rotations which boost the re
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ky �GeV� 0.4 0.2 0.0 �0.2 �
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[2] B. Pasquini, and S. Boffi, Phys
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The appearance of both |+〉 and |
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2.2 Intrinsic Transverse Motion Qua
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are still complex: for a given corr
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This last is required to complete t
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[16] P.G. Ratcliffe and O.V. Teryae
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Figure 1: a)[left] μpG p E /Gp M (
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4 Conclusion We introduced a simple
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√ δΔq8 x for Δq8 and γΔGx fo
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understanding of polarized light qu
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They are inverse powers of Q 2 kine
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accounts approximately for the TM a
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POTENTIAL FOR A NEW MUON g-2 EXPERI
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When the momentum increases (p >p0)
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EVOLUTION EQUATIONS FOR TRUNCATED M
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4 Perspectives Evolution equations
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NEW DEVELOPMENTS IN THE QUANTUM STA
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statistical approach compared to th
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POLARIZED HADRON STRUCTURE IN THE V
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g 3 A =Δuv(Q 2 ) − Δdv(Q 2 ), g
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AXIAL ANOMALIES, NUCLEON SPIN STRUC
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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”
Page 192 and 193: If we admit a non-zero quark transv
Page 194 and 195: which is trivial in collinear LO ap
Page 196 and 197: In figure 3 the expected errors on
Page 198 and 199: [12] A. V. Efremov and O. V. Teryae
Page 200 and 201: Figure 1: The COMPASS spectrometer.
Page 202 and 203: Comparing this formula to the inclu
Page 204 and 205: Figure 5: Comparison of COMPASS inc
Page 206 and 207: [9] B. Adeva et al. (SMC Coll.), Ph
Page 208 and 209: q T sin( φ-φ ) M AUT 0.14 0.12 0.
Page 210 and 211: proton beam is planned. References
Page 212 and 213: Run Year √ s (GeV) Polarization R
Page 214 and 215: ackground fraction, and asymmetry i
Page 216 and 217: At √ s = 200 GeV, ALL(pp → π
Page 218 and 219: [6] D. de Florian, W. Vogelsang, an
Page 220 and 221: higher energies, where the cross se
Page 222 and 223: Figure 3: The experimental results
Page 224 and 225: kinematic range to low values of Bj
Page 226 and 227: 3 Semi-Inclusive DIS Collins and Si
Page 228 and 229: Unpolarized target asymmetries. The
Page 230 and 231: 4 Summary Since the end of data-tak
Page 232 and 233: polarization as well as a construct
Page 234 and 235: Finally the COMPASS reconstruction
Page 236 and 237: tained in the NLO QCD approximation
Page 238 and 239: with only modern NN potential are r
Page 240 and 241: (a) (b) Figure 3: (a) T20 data take
Page 244 and 245: As is seen in Fig. 1 values of the
Page 246 and 247: SEMI-INCLUSIVE DIS AND TRANSVERSE M
Page 248 and 249: The yellow band in Fig. 1 is the re
Page 250 and 251: At leading twist, a third asymmetry
Page 252 and 253: THE COMPLETION OF SINGLE-SPIN ASYMM
Page 254 and 255: A N , % 30 20 10 0 0 0.2 0.4 0.6 0.
Page 256 and 257: Unexpectedly large single spin asym
Page 258 and 259: THE GENERALIZED PARTON DISTRIBUTION
Page 260 and 261: , E) H ~ (H, I Im C 5 4 3 2 1 Q = 1
Page 262 and 263: Reducing to a common denominator (
Page 264 and 265: LAMBDA PHYSICS AT HERMES S. Belosto
Page 266 and 267: analysis was carried out reconstruc
Page 268 and 269: SPIN PHYSICS AT NICA A. Nagaytsev J
Page 270 and 271: original software packages (MC simu
Page 272 and 273: MEASUREMENTS OF TRANSVERSE SPIN EFF
Page 274 and 275: to “near-side” and “away-side
Page 276 and 277: THE FIRST STAGE OF POLARIZATION PRO
Page 278 and 279: In paper [12] the study was made of
Page 280 and 281: emphasis to increase the statistics
Page 282 and 283: Table 2: The parameters of the main
Page 284 and 285: POLARIZATION MEASUREMENTS IN PHOTOP
Page 286 and 287: With a polarized electron beam inci
Page 288 and 289: Figure 3: Preliminary helicity asym
Page 290 and 291: 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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