Measurement of differential cross sections of p(e,e’p+)n for high-lying resonances at Q2 < 5GeV2 K. Park What we can learn from this experiment ? NSTAR 2013 Workshop May, 27 - 30, 2013

Why e.m. probes for study of hadron structure ? B=N,N*,D* Allows to address central question: “ What are the relevant degrees-of-freedom at varying distance scale ?” N q q q Why do we use electromagnetic probes to study hadron structure? I think the answer is that the e.m. probe allows us to efficiently address the central question of hadron physics: What are the relevant degrees of freedom at varying distance scales? To simply illustrate this I show here the quark propagator mass calculated in LQCD, Dyson Schwinger, and other approaches as a function of the momentum transfer. In the e.m. probe we can vary the resolution and momentum transfer. In doing so, we probe the effective degrees of freedom in the nucleon from meson-nucleon, to constituent quarks, to elementary partons. The study of nucleon resonance transitions provides a testing ground for our understanding of these effective degrees of freedom. e' e' e' g* g* g* e e e NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park 2

Electroproduction Amplitudes Sz= 1 Sz= 1/2 photocoupling amplitudes → A1/2, A3/2 and S1/2 Sz= 1 Sz= 1/2 Sz= 0 S1/2 Sz= 1/2 p g* N N* Pion electroproduction multipole amplitude → El, Ml and Sl . l : the orbital angular momentum in Nπ system. ± sign : spin of proton couples to the orbital momentum. Electroproduction of hadronic final states via s-channel resonance decay. A: transverse coupling S : scalar coupling respect to the total helicity of the gammaN system. The electroproduction of an excited state can be described in terms of 3 photocoupling amplitudes A1/2, A3/2 and S1/2 . We still need to learn a lot more about the light quark baryon spectrum. It has been studied mostly with pion probes. However, there may be many states that do not coupleto pions, especially higher mass state, while possibly coupling to photons. The spectrum can tell us about the underlying symmetry properties due to different quark-gluon configurations, or interaction mechanism At different photon virtualities we probe how the relevant dof change as a function of the distance scale. The quantities of interest are the helicity amplitudes A1/2,... as a function of Q2. Since both photon and nucleon carry spin, we probe the spin structure in the regime of strong QCD. Our main tool in resonance studies is meson production. However, mesons are not only produced via resonance decays. In order to understand the full production mechanism in terms of resonant and non-resonant amplitudes we need to further develop, what one may call the Standard Model of meson production. Finally, N* electroexcitation allows us to better understand the observed connections between the nucleon resonance region and the deeply inelastic regime. A1/2, A3/2,S1/2 El, Ml ,Sl NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

from CLAS Q2 evolution in low-mass has been done so far… A1/2 S1/2 GM* P11(1440) D(1232) from CLAS Q2 < 5.0GeV2 GM* A1/2 A1/2 PRC77, 015208 (2008) PRC78, 045209 (2008) PRC80, 055203 (2009) PRC73, 025204 (2006) PRL97, 112003 (2006) PRC72, 058202 (2005) PRC68, 032201 (2005) PRL88, 122001 (2002) * Publication includes analyses of Np channels … S1/2 REM S1/2 RSM A3/2 NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park 4

Q2 evolution in high-mass … ? I may skip this page …. By words, high mass is poorly known….. (1996) 30 years ago…. Transverse photocoupling amplitudes for state belongs to the [70,1-] super-multiplets 0 =neutron + = proton Data : Breuker H. et al, Z. Phy. C 17 (1983) 121 (Bonn) Foster F. and Hughes G : Rep. Prog. Phys. 46 (1983) 1445 Curves : SQTM. Dashed-lins : different parametrization of th S11. D13 RPP (PDG) J. Phys. G 37 (2010) I.G. Aznauryan, Phys. Rev. C 72 (2005) MAID 2007 (global fit) NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Single and double pion electroproduction 2PION CHANNEL HAS MORE STRONG SENSTIVITY ON THE HIGH-LYING RESONSNCES THAN SINGLE PION CHANNELS. HOWEVER, SIGNLE PION AND DOUBLE PION HAS THEIR OWN SPIN-FAVOR DECOMPOSITION, BRANCHING FRACTION… S11(1650), F15(1685) = 60%-90% FOR SINGLE PION HADRONIC DECAY PROMINENT N* FOR W<1.8GeV W (GeV) NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Single and double pion electroproduction 2PION CHANNEL HAS MORE STRONG SENSTIVITY ON THE HIGH-LYING RESONSNCES THAN SINGLE PION CHANNELS. HOWEVER, SIGNLE PION AND DOUBLE PION HAS THEIR OWN SPIN-FAVOR DECOMPOSITION, BRANCHING FRACTION… S11(1650), F15(1685) = 60%-90% FOR SINGLE PION HADRONIC DECAY PROMINENT N* FOR W<1.8GeV W (GeV) NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Kinematic binning ~ 29K cross-section data Exclusive single positively charged pion electroproduction off the proton Q2 < 5.0GeV2 This Work W (GeV) E0 =5.499 GeV Kinematic binning ~ 29K cross-section data Variable Range Number of bin (size) W 1.6 ~2.0 GeV 5(40MeV) , 3(60MeV) Q2 1.7 ~4.5 GeV2 5 (vary) cos qp* -1.0~+0.5,+0.5~+1.0 7 (0.2) , 10 (0.05) fp* 0o ~ 360o 24 (15o) , 48(7.5o) NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Differential cross sections Single pion electroproduction cross-section w/ one-photon exchange approx. NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary Fit differential cross sections vs. f* Samples Exp. e1-f NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary Fit differential cross sections vs. f* Samples A + B cos f + C cos2 f Samples Exp. e1-f NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary Differential cross sections vs. W MAID 2003 (Isobar model) DMT2001 (Dynamic model) MAID 2007 (Isobar model) Exp. e1-f : this work PRC 77, 015208 (2008) NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary Differential cross sections vs. W W (GeV) MAID 2003 (Isobar model) DMT2001 (Dynamic model) MAID 2007 (Isobar model) Exp. e1-f : this work PRC 77, 015208 (2008) NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary Structure functions @ W=1.62GeV (sT + e sL) (sTT) (sLT) Exp. e1-f PRC 77, 015208 (2008) (sLT) ** systematic uncertainty is NOT taken into account. NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary Structure functions @ W=1.74GeV (sT + e sL) (sTT) (sLT) Exp. e1-f (sLT) ** systematic uncertainty is NOT taken into account. NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Analysis ; (forward angle with finer binning) (sTT) NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Analysis ; (forward angle with finer binning) (sTT) +0.5 +0.9 +0.7 cosine bins +1.0 0.575 0.625 0.525 0.675 0.725 0.775 0.825 0.875 0.925 0.975 fine cosine bins at forward angle NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary Preliminary differential cross sections fine-angle binning at forward region Preliminary Only Yields, acceptances, radiative corrections and normalization were taken into account to get cross sections. No detail efficiencies and corrections are not yet applied. Samples NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary Preliminary differential cross sections fine-angle binning at forward region Preliminary Only Yields, acceptances, radiative corrections and normalization were taken into account to get cross sections. No detail efficiencies and corrections are not yet applied. NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary Structure functions fine-angle binning at forward region (sTT) Exp. e1-f w/ fine-bin Exp. e1-f PRC 77, 015208 (2008) NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary Structure functions W=1.89, 1.95, 2.01 GeV (sT + e sL) Exp. e1-f Exp. e1-f w/ fine-bin NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary ? ? Structure functions W=1.89, 1.95, 2.01 GeV (sT + e sL) Exp. e1-f Exp. e1-f w/ fine-bin NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary Zoom–in forward angle region (sT + e sL) W=1.89 GeV Exp. e1-f coarse-bin Exp. e1-f w/ fine-bin Exp. e1-f w/ hyper-fine bin NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary Legendre moments Exp. e1-f (dW= 20MeV) PRC 77, 015208 (2008) NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary Helicity Amplitude Extraction : N(1680)5/2+ RPP (PDG) J. Phys. G 37 (2010) I.G. Aznauryan, Phys. Rev. C 72 (2005) M. Dugger Phys. Rev. C 76 (2007) Do not show 2pion data SHOULD mention, no systematic uncertainty taken into account for either data and extraction of the helicity amplitude. Q2=0GeV2 should be updated with M.Dugger data value. Gianini (sound like : Janini) Quark model calculation curve ?? This analysis, I.G. Azauryan (UIM) MAID global analysis M.M. Gianini/E. Santopinto (hQCM) WARNING : systematic uncertainty is NOT taken into account. NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary Helicity Amplitude Extraction : N(1680)5/2+ RPP (PDG) J. Phys. G 37 (2010) I.G. Aznauryan, Phys. Rev. C 72 (2005) M. Dugger Phys. Rev. C 76 (2007) This analysis, I.G. Azauryan (UIM) MAID global analysis M.M. Gianini/E. Santopinto (hQCM) WARNING : systematic uncertainty is NOT taken into account. NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary Helicity Amplitude Extraction : N(1680)5/2+ I.G. Aznauryan, Phys. Rev. C 72 (2005) This analysis, I.G. Azauryan (UIM) MAID global analysis M.M. Gianini/E. Santopinto (hQCM) WARNING : systematic uncertainty is NOT taken into account. NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary Helicity Amplitude Extraction : N(1720)3/2+ RPP (PDG) J. Phys. G 37 (2010) I.G. Aznauryan, Phys. Rev. C 72 (2005) M. Dugger Phys. Rev. C 76 (2007) This analysis, I.G. Azauryan (UIM) MAID global analysis M.M. Gianini/E. Santopinto (hQCM) WARNING : systematic uncertainty is NOT taken into account. NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary Helicity Amplitude Extraction : N(1720)3/2+ RPP (PDG) J. Phys. G 37 (2010) I.G. Aznauryan, Phys. Rev. C 72 (2005) M. Dugger Phys. Rev. C 76 (2007) This analysis, I.G. Azauryan (UIM) MAID global analysis M.M. Gianini/E. Santopinto (hQCM) WARNING : systematic uncertainty is NOT taken into account. NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Summary and Plans Using the exclusive single positively charged pion off the proton data, the differential cross sections have been measured for high-lying resonances. (1.6 GeV< W< 2.0 GeV, 1.7 GeV 2< Q2 < 4.5 GeV 2). Preliminary results are consistent with the published data. Angular distribution at high W likely indicate the pion pole contribution. Preliminary helicity-amplitudes for F15(1680), P13(1720) resonances have been extracted using a unitary isobar model. Systematic study for fine-bin data is on going. Combined analysis of available and future data on all exclusive meson electroproduction channels at W >1.6 GeV and at Q2 >2.0 GeV 2 within the framework of coupled channel approaches will improve considerably our knowledge on high mass N*-state electro-couplings. NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Thank you for your attention Questions/comments ?

Preliminary Helicity Amplitude Extraction : N(1680)5/2+ Exp. e1-f ( this analysis ) MAID global analysis I. Aznaryannna (Old) NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary Helicity Amplitude Extraction : N(1720)3/2+ Exp. e1-f ( this analysis ) MAID global analysis I. Aznaryannna (Old) NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Helicity Amplitude Extraction: S11, S31, D13, D33 ad = 0.53 as = 0.46 S11: N(1650) 1/2- S31: Delta(1620) 1/2- D13: N(1700) 3/2- D33 : Delta(1700) 3/2- Preliminary Exp. e1-f ( this analysis ) SQTM SQTM NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Exclusive single positively charged pion electroproduction Exclusive single positively charged pion electroproduction off the proton Q2 < 5.0GeV2 from CLAS PRC85, 035208(2012) Eur. Phys. J. A 49, 16 (2013) PRC77, 015208(2008) PRC78, 045209(2008) PRC80, 055203(2009) This Work GM* REM RSM A1/2 S1/2 P11(1440) D(1232) S11(1535) D13(1520) ds/dt vs. xB, Q2, -t (<5GeV2) G1 and GA form factors W (GeV) NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park

Preliminary Zoom–in forward angle region (sT + e sL) W=1.89 GeV (sTT) (sLT) Exp. e1-f Exp. e1-f w/ fine-bin Exp. e1-f w/ hyper-fine bin NSTAR 2013 Workshop at Valencia SPAIN May. 27-30, 2013 K. Park