Extracting Resonance Parameters from Exclusive Electroproduction off Protons at CLAS. Kijun Park. August 23, 2017

Transcription

1 Extracting Resonance Parameters from Exclusive Electroproduction off Protons at CLAS Kijun Park August 23, 27

2 Overview Introduction 2 Physics Result Highlight! 3 New Interesting Results! 4 Summary K. Park (JLAB) NStar 27 August 23, 27 / 23

3 Long Range Plan 25 ( 2 st Century Nuclear Science ). Fully utilize programs at existing & under construction facilities (JLab2, RHIC, NSCL, FRIB,...) (a) How did visible matter come into being and how does it evolve? (b) How does subatomic matter organize itself and what phenomena emerge? (c) Do we understand the fundamental interactions that are basic to the structure of matter? K. Park (JLAB) NStar 27 August 23, 27 / 23

4 How to approach? Public Lecture by, C. Robert, Monday K. Park (JLAB) NStar 27 August 23, 27 / 23

5 The most challenging problems in Hadron Physics Non-perturbative DCSB generates more than 98% of dress quark masses as well as dynamical structure although, Higgs mechanism < 2% in N, N masses Quark-gluon confinement in bayrons emerges from QCD; dressed quarks, meson-baryon cloud, dressed gluon,... Talk by, V. Mokev, C. Robert, Sunday, P Study of the excited states of the nucleon is important step in the development of a fundamental understanding of strong interaction; QGP Hadrons Talk by V. Burkert, Sunday, P The most fundamental question: WHAT ARE THE RELEVANT DEGREE-OF-FREEDOM AT VARYING DISTANCE SCALE? K. Park (JLAB) NStar 27 August 23, 27 2 / 23

6 SU(6) O(3) Classification of Baryons There are questions about underlying DoF of some well known state...but still many open questions.. related with QCD, FT, CQM, LQCD... Effective degrees of freedom / Transition charge densities / Running quark mass Nature of States K. Park (JLAB) NStar 27 August 23, 27 3 / 23

7 SU(6) O(3) Classification of Baryons There are questions about underlying DoF of some well known state...but still many open questions.. related with QCD, FT, CQM, LQCD... Effective degrees of freedom / Transition charge densities / Running quark mass Nature of States K. Park (JLAB) NStar 27 August 23, 27 3 / 23

8 Analysis Chain Modified the original flowchart Credit to R. Briceno K. Park (JLAB) NStar 27 August 23, 27 4 / 23

9 Analysis Approaches and CLAS data analyses UIM, DR for π + n and π p - [Speaker: K. Park, N. Markov] I. G. Aznauryan, Phys. Rev. C67, 529 (23). I. G. Aznauryan et al., CLAS Coll., Phys. Rev. C8, 5523 (29). I. G. Aznauryan et al., CLAS Coll., Phys. Rev. C9, 4523 (25). Extension of UIM, DR, Data fit for ηp, ωp - [Speaker: E. Phelps] I. G. Aznauryan, Phys. Rev. C68, 6524 (23). H. Denizli et al., CLAS Coll., Phys. Rev. C76, 524 (27). JM-MB model, Data fit for π + π p - [Speaker: A. Trivedi, G. Fedotov] V. I. Mokeev, V. D. Burkert et al., Phys. Rev. C8, 4522 (29). V. I. Mokeev et al., CLAS Coll., Phys. Rev. C86, 3523 (22). V. I. Mokeev, V. D. Burkert et al., Phys. Rev. C93, 546 (26). Overview: NN Electrocoupling Extraction from CLAS data Talk by V. Mokeev, Tuesday, P5 Global coupled-channel analyses for exclusive γn, πn, ππn, K Λ, K Σ Talk by H. Kamano [ANL-Osaka], Monday, P3 Talk by M. Doering [Juli-Bonn], Tuesday, P5 K. Park (JLAB) NStar 27 August 23, 27 5 / 23

10 Analysis Approaches Two different approaches: UIM, DR UIM BG UIM is built from nucleon exchange in s-, u- and π,ω,ρ exchange in t- channel Unitarization of multipole amplitudes in the K-matrix approximation Resonance contributions are parameterized in the unified BW form with energy dependence DR Fixed-t dispersion relation for the invariant amplitude Re-Amplitude to Born-term (nucleon exchange in s-,u-, π exchange in t-channel) Integral Im-Amplitude with the isospin structure Two model-uncertainties BG determination in the UIM and Born term in DR A width and mass of resonances from PDG Take into account... All(3) **** and *** states in the st,2 nd,3 rd (95)F 35, (95)F 37 in 4 th resonance region Same BR from PDG22 K. Park (JLAB) NStar 27 August 23, 27 6 / 23

11 Data Analyses, ep e πn, ep e ππn assume: one photon exchange approximation d 5 σ de f dω edω = Γ ν d2 σ π dω π e-beam e, γ * θ e φ π * θ π * π + z-axis where, Γ ν:virtual photon flux: ǫ: virtual photon polarization: α (W 2 Mp 2 )E f 2π 2 Q 2 2M pe e ǫ, ( +2 (+ ν2 Q 2 ) ) tan 2 θe 2 SCATTERING PLANE n REACTION PLANE d 2 σ dω π = p π k (σ +h ) 2ǫ( ǫ)σ π LT sinθ πsinφ π σ = σ U +ǫσ TT sin 2 θ πcos2φ π + 2ǫ(+ǫ)σ LT sinθ πcosφ π where, h: beam helicity state σ : unpolarized cross-section σ U = σ T +ǫσ L Kinematics is completely defined by five variables (Q 2, W, θ π, φ π, and φ e) K. Park (JLAB) NStar 27 August 23, 27 7 / 23

12 Let me briefly talk about the highlighted results... K. Park (JLAB) NStar 27 August 23, 27 8 / 23

13 Let me briefly talk about the highlighted results... K. Park (JLAB) NStar 27 August 23, 27 8 / 23

14 In particular, ep e π + n Kinematic range W(excitation), Q 2 (resolution) of γ p nπ + From the near pion threshold to Deep Process regime K. Park (JLAB) NStar 27 August 23, 27 9 / 23

15 ep e π + n for low lying N (W =.5.69 GeV) Transition Form Factors for N(44)/2 + (old conv: P (44) ) A /2 shows a sign change in Q 2.8 GeV 2 S /2 is large at low Q 2 and drop off smoothly with increasing Q 2 A complex interplay btw inner core of quarks in the first radial excitation and external MB cloud LF RQM (thick red curve), Quark core in DSEQCD (thick dashed curve) MB cloud contribution (shaded band) Talk by V. Burkert, Tuesday, D3; J. Segovia, Tuesday, P6; H. Kamano, Monday, P3;... Phys.Rev.C78, 4529 (28) K. Park (JLAB) NStar 27 August 23, 27 / 23

16 ep e π + n for low lying N (W =.5.69 GeV) Transition Form Factors for N(535)/2 (old conv: S (535)) βnη PDG =.45.6 βnπ PDG =.485 & βnη PDG =.46, excellent agreement Sensitive to long. as well (strong interference S -P ) Previously Opposite sign of S /2! Impossible to change in quark model (LFRQM failed for S /2!) Combined with the difficulties in the description of () large width of S (535) ηn (2) large S (535) φn, ΛK couplings It shows that 3q picture for S (535) should be complemented! [I.Aznuryan] Talk by G. Ramalho, Tuesday, D3;... [ solid: LFRQM, dash-dot: LCSR ] K. Park (JLAB) NStar 27 August 23, 27 / 23

17 ep e π + n for low lying N (W =.5.69 GeV) Transition Form Factors for N(52)3/2 (old conv: D 3(52) ) A /2 is large at high Q 2, A 3/2 is small at high Q 2 [ : RPP(24),, : DESY, NINA data] A D3 /2 A D3 3/2 = 3 ( Q2 α ) A hel = A2 /2 A2 3/2 A 2 /2 +A2 3/2 Asymptotic Q 2 behavior of A hel vs. Q 2 - NRQ simple harmonic oscillator model (solid line) with spin, orbit flip amplitudes A /2 A 3/2 at low Q 2, A 3/2 A /2 at high Q 2 K. Park (JLAB) NStar 27 August 23, 27 2 / 23

18 ep e π + n for high lying N (.65 < W < 2. GeV) differential cross-sections (2 bins of φ ) for third resonance region dσ/dω [µb/sr] dσ/dω [µb/sr] dσ/dω [µb/sr] dσ/dω [µb/sr] dσ/dω [µb/sr] 2 π = =-.5 2 π π = π = π = φ π * (deg) 2 π = π = π =. 2 3 π = π = φ π * (deg) K. Park (JLAB) NStar 27 August 23, 27 3 / 23

19 ep e π + n for high lying N (.65 < W < 2. GeV) differential cross-sections (24 bins of φ ) for third resonance region dσ/dω [µb/sr] dσ/dω [µb/sr] dσ/dω [µb/sr] dσ/dω [µb/sr] dσ/dω [µb/sr].5 π = π = π = π = =.7 2 π 2 3 φ π * (deg).5 π = π = π =. 2 3 =.5 2 π 2 3 π = φ π * (deg) K. Park (JLAB) NStar 27 August 23, 27 3 / 23

20 Moorhouse selection rule must be violated! Spin-dependent potential from one-gluon-exchange and SU(6) O(3) symmetry breaking, color hyperfine interaction Hhyper is introducing mass splitting and configuration mixing in SU(6) multiplets Isgur, Karl, PRL 4, 269 (978). 3(Si rij )(Sj rij ) 2αs 8π 3 Hhyper = 3mi mj 3 Si Sj δ (rij ) + r 3 Si Sj r2 ij ij [R. G. Moorhouse, Phys. Rev. Lett. 6, 77 (966)] K. Park (JLAB) NStar 27 August 23, 27 4 / 23

21 ep e π + n for high lying N (W = GeV) Transition Form Factors for N(675)5/2 (old conv: D 5(675) ) SQTM, Moorhouse selection rule: suppression Transverse Amplitudes Solid: M. M. Gianini/E. Santopinto (hqcm) dash: D.Merten& U.Loring(23) Non-quark contributions dominance, A strong coupling A /2 for Q 2 < 4 GeV 2 Significant MB contribution from the dynamical coupled-channel model (dash-dot: B. Julia-Diaz, T-S. H. Lee, A. Matsuyama) A strong suppression of A 3/2 for Q 2 >.8 GeV 2 A /2 ( -3 GeV -/2 ) 2 A 3/2 ( -3 GeV -/2 ) 2 S /2 ( -3 GeV -/2 ) Q 2 (GeV 2 ) 2 4 Q 2 (GeV 2 ) 2 4 Q 2 (GeV 2 ) K. Park (JLAB) NStar 27 August 23, 27 5 / 23

22 ep e π + n for high lying N (W = GeV) Transition Form Factors for N(68)5/2 + (old conv: F 5(68) ) RPP(PDG:24), V.Mokeev& I.G.Aznauryan(23), I.G.Aznauryan(25) Solid: M.M.Gianini/E.Santopinto (hqcm), dash-dot: Z.Lee& F.Close(99), dash: D.Merten& U.Loring(23) All models estimates amplitudes larger A /2 ( lower A 3/2 ) than data MB contribution should be taken into account? A /2 ( -3 GeV -/2 ) A 3/2 ( -3 GeV -/2 ) 5 5 S /2 ( -3 GeV -/2 ) - -2 A hel Q 2 (GeV 2 ) 2 4 Q 2 (GeV 2 ) Q 2 (GeV 2 ) Q 2 (GeV 2 ) K. Park (JLAB) NStar 27 August 23, 27 6 / 23

23 ep e π + n for high lying N (W = GeV) Transition Form Factors for N(7)/2 + (old conv: P (7) ) Finite size of A /2 for Q 2 < 2.5 GeV 2 Finite size and negative of S /2 for all given Q 2 GeV 2 A /2 ( -3 GeV -/2 ) S /2 ( -3 GeV -/2 ) Solid: M.M.Gianini E.Santopinto (hqcm) Q 2 (GeV 2 ) Q 2 (GeV 2 ) K. Park (JLAB) NStar 27 August 23, 27 7 / 23

24 Deep Inelastic Scattering Regime (W > 2. GeV) Transition between hadronic and partonic picture of strong interaction GPD Correlations of longitudinal momentum fraction with transverse spatial position DVMP: N(e,e NM), M =π, ρ, φ,... Connection to the transversity GPD Blue box [K.Park, et al., Eur. Phys. J. A49 6, (23)] Q 2 [GeV 2 ] t [GeV 2 ] K. Park (JLAB) NStar 27 August 23, 27 8 / 23

25 Hard Exclusive Forward, Large-angle γ p nπ + Solid (dσ/dt), dashed curves (dσ L /dt) Red curves: J. M. Laget, Regge-model Blue curves: M. Kaskulov, Hybrid (hadron-parton) model K. Park (JLAB) NStar 27 August 23, 27 9 / 23

26 Hard Exclusive Forward, Large angle γ p nπ + Solid (dσ/dt), dashed curves (dσ L /dt) Magenta curves: M. Kaskulov, Duality model Transverse: resonance excitation Longitudinal: t-channel meson exchange Blue curves: G-K : Transversity of GPDs Partonic model (handbag diagram) (But w/o adjusting Jlab kinematics) K. Park (JLAB) NStar 27 August 23, 27 2 / 23

27 New upcoming results 27!!! under CLAS 6 Paper Review K. Park (JLAB) NStar 27 August 23, 27 2 / 23

28 Hard Exclusive Backward angle γ p nπ + Q 2 (GeV 2 ) Yield/2 MeV t (GeV 2 ) Mx (eπ + X) [GeV] K. Park (JLAB) NStar 27 August 23, 27 2 / 23

29 Structure functions vs. πn-tda calculation σ U, σ LT, σ TT (nb/sr) Q 2 (GeV 2 ) σ T + ǫσ L ( ), σ TT ( ), and σ LT ( ) A recent theoretical calculation as a function of ξ Q 2 /(Q 2 + 2W 2 ) Nucleon to meson TDAs provide new information about correlation of partons inside hadrons Curves : the contribution of πn-tda model Red band: BLW NNLO a, dark blue band: COZ b, and light blue band: KS c Theoretical understanding is growing up: spectral representation for πn TDA based on quadruple distributions; factorized Ansatz for quadruple distributions with input at ξ =. Open questions: proof of factorization theorems, interpretation in the impact parameter space, analytic properties of the amplitude a A. Lenz, et al., Phys.Rev. D79, 937, (29). b V.L Chernyak, et al., Z. Phys. C42, 583 (989).. c I.D. King et al., Nucl. Phys. B279, 785, (987). K. Park (JLAB) NStar 27 August 23, / 23

30 Summary Extraction of the transition form factor should be carried out through the differential cross-sections/asymmetries measurements for near full angles and large kinematics W, Q 2 Precision data for γ p nπ + from CLAS allows to extract the helicity amplitudes for various reonance states, N(44)/2 +, N(52)3/2, N(535)/2, N(675)5/2, N(68)5/2 +, and N(7)/2 + Coupled-channel analysis (including πn, ππn, KY,...) is crucial in particular high W and this will improve considerably our knowledge on N -state electro-couplings. Full Mass Spectrum with Q 2 evolution and Coupled-Channel Analyses help us to map out nucleon structure in terms of the effective degree of freedom K. Park (JLAB) NStar 27 August 23, / 23