Strong Interaction from Quarks to Nuclei Ralf W. Gothe Many manifestations of nonperturbative QCD International workshop on nonperturbative phenomena in hadron and particle physics April 30 – May 5, 2018, Camburi, São Paulo, Brazil γ v NN* Experiments: The Best Access to the Quark and Baryon Structure? Analysis and New Results: Exclusive, quasi-free, and final state interaction! Outlook: New experiments with extended scope and kinematics! Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 This work is supported in parts by the National Science Foundation under Grant PHY 1505615. 1
Build your Mesons and Baryons … ? Frank Wilczek, Physics Today, August 2000 Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 2
Hadron Structure with Electromagnetic Probes Study the structure of the nucleon spectrum in the domain π,ρ,ω … Q 2 where dressed quarks are the major active degree of freedom. Explore the formation of excited nucleon states in interactions low of dressed quarks and their emergence from QCD. k N,N * , ∆,∆ * … 3q-core+MB-cloud K 2 µ N P 2 µ * Q 2 = − K µ 3q-core 2 K 1 µ N P 1 µ high pQCD Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 3
Hadron Structure with Electromagnetic Probes Study the structure of the nucleon spectrum in the domain Quark mass extrapolated to the chiral limit, where q π,ρ,ω … Q 2 where dressed quarks are the major active degree of freedom. is the momentum variable of the tree-level quark Explore the formation of excited nucleon states in interactions low propagator using the Asqtad action. of dressed quarks and their emergence from QCD. q N,N * , ∆,∆ * … meson dressed quark LQCD, DSE and … 3q-core+MB-cloud quark mass (GeV) confinement 3q-core current quark e.m. probe high pQCD Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 4
Baryon Excitations and Quasi-Elastic Scattering Quark-Hadron Duality PRL 16 (1970) 1140, PR D4 (1971) 2901 E.D. Bloom and F.J. Gilman Paticle and Nuclei, Povh et al., MAMI B W = 1.9 GeV E’ = 17.6 GeV ν = 2.37 GeV Q 2 = 1.72 GeV m q = Q 2 /2 ν m q = 0.36 GeV p F = 0.67 GeV Deep Inelastic Scattering S. Stein et al., PR D22 (1975) 1884 Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 5
Baryon Excitations and Quasi-Elastic Scattering quasi-elastic off point-like constituents Deep Inelastic Scattering M. Breidenbach et al., Phys. Rev. Lett. 23 (1969) 935 Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 6
Inclusive Structure Function in the Resonance Region P. Stoler, PRPLCM 226, 3 (1993) 103-171 Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 7
Baryon Excitations and Quasi-Elastic Scattering hard and confined quasi-elastic hard soft Deep Inelastic Scattering S. Stein et al., PR D22 (1975) 1884 Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 8
Baryon Excitations and Quasi-Elastic Scattering λ γ p =1/2 γ v N λ γ p =3/2 Deep Inelastic Scattering S. Stein et al., PR D22 (1975) 1884 Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 9
Transition Form Factors Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 10
Data-Driven Data Analyses QCD Consistent Results DSE, QM N*, Δ * LQCD Single meson production: Unitary Isobar Model (UIM) Fixed- t Dispersion Relations (DR) Amplitude Double pion production: Reaction analysis Models Unitarized Isobar Model (JM) Coupled-Channel Approaches: EBAC ⇒ Argonne-Osaka JAW ⇒ Jülich-Athens-Washington ⇒ JüBo Data BoGa ⇒ Bonn-Gatchina Hadronic Electromagnetic Int. J. Mod. Phys. E, Vol. 22, 1330015 (2013) 1-99 production production Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 11
Electrocouplings of N(1440)P 11 from CLAS Data S 1/2 A 1/2 N π (UIM, DR) N ππ (JM) preliminary N ππ (JM) 2012 PDG Consistent results obtained in the low-lying resonance region by independent analyses in the exclusive N π and p π + π - final-state channels – that have fundamentally different mechanisms for the nonresonant background – underscore the capability of the reaction models to extract reliable resonance electrocouplings. Phys. Rev. C 80, 055203 (2009) 1-22 and Phys. Rev. C 86, 035203 (2012) 1-22 Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 12
Electrocouplings of N(1440)P 11 History 10 -3 GeV -1/2 Lowest mass hybrid baryon should be J P =1/2 + as Roper. In 2002 Roper A 1/2 results were consistent with a hybrid state. Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 13
Transition Form Factors and QCD Models Roper resonance P 11 (1440) PDG 2013 update nrQM + q³g q 3 +Nσ LC QM + q³qq + N-Meson - q 2 q + … or q 3 G - … … all have distinctively different Q 2 dependencies A 1/2 has zero-crossing near Q 2 =0.5 and becomes dominant amplitude at high Q 2 . Consistent with radial excitation at high Q 2 and large meson-baryon coupling at small Q 2 . Eliminates gluonic excitation (q 3 G) as a dominant contribution. Nick Tyler closes the 1-2 GeV 2 gap for single pion production. Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 14
Roper Transition Form Factors in DSE Approach N(1440)P 11 J. Segovia et al., Phys. Rev. Lett. 115 , 171801 CLAS Data CLAS Data DSE Contact Radial excitation … DSE Realistic longer tail … r R /r p =1.8 Inferred meson-cloud contribution … color must be screened … greater Anticipated complete result need for a meson- baryon cloud! Importantly, the existence of a zero in F 2 is not influenced by meson-cloud effects, although its precise location is. Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 15
Roper Transition Form Factors in DSE Approach N(1440)P 11 J. Segovia and C.D. Roberts , arXiv:1607.04405 DSE realistic Flavor separation CLAS Data CLAS Data Scalar diquark Pseudovector Diquark exchange Diquark contributions DSE Realistic d-quark Dressed quark u-quark DSE Contact DSE Contact Diquarks Exchange quark DSE Realistic DSE Realistic Inferred meson-cloud contribution Inferred meson-cloud contribution Anticipated complete result Anticipated complete result Electrocoupling Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 16
DSE and EBAC/ANL-Osaka Approaches … more ( π,ππ ), ( π,πη ), and ( π, KY) data needed Semi-quantitative agreement with the first DSE 3-dressed-quark core radial excitation Two poles associated with the Roper resonance and one with the next higher P 11 resonance are all seeded by the same bare 3-dressed-quark state Int. J. Mod. Phys. E, Vol. 22, 1330015 (2013) Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 17
Electrocouplings of N(1520)D 13 and N(1535)S 11 10 -3 GeV -1/2 10 -3 GeV -1/2 10 -3 GeV -1/2 A 3/2 A 1/2 A 1/2 π + π − p π + π − p N π Argonne Osaka / EBAC DCC MB dressing (absolute values) 2010 2009 2012 E. Santopinto, M. Giannini, hCQM PRC 86, 065202 (2012) η p S. Capstick, B.D. Keister (rCQM) CLAS/Hall-C PRD51, 3598 (1995) Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 18
LQCD & Light Cone Sum Rule (LCSR) Approach N(1535)S 11 N S 11 LQCD is used to determine the moments of N* distribution amplitudes (DA) and the N* electrocouplings are determined from the respective DAs within the LCSR framework. Calculations of N(1535)S 11 electrocouplings at Q 2 up to 12 GeV 2 are already available and shown by shadowed bands on the plot. LQCD & LCSR electrocouplings of others N* resonances will be evaluated as part of the commitment of the University of Regensburg group. Int. J. Mod. Phys. E, Vol. 22, 1330015 (2013) 1-99 Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 19
LQCD, LCSR, and DSE Approaches N S 11 N(1535)S 11 x i is the momentum fraction of i-th valence quark I.V. Anikin et al., Phys. Rev. D92 , 014018 (2015) and V.M. Braun et al., Phys. Rev. D89 , 094511 (2014) N S 11 C.D. Roberts and C. Merzag, EPJ Web Conf. 137 , 01017 (2017) Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 20
Evidence for the Onset of Precocious Scaling? I. G. Aznauryan et al., Phys. Rev. C80, 055203 (2009) S 11 Q 3 A 1/2 F 15 Q 5 A 3/2 P 11 Q 3 A 1/2 D 13 Q 5 A 3/2 A 1/2 α 1/Q 3 F 15 Q 3 A 1/2 A 3/2 α 1/Q 5 D 13 Q 3 A 1/2 Ralf W. Gothe Camburi , São Paulo, April 30 - May 5, 2018 21
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