Partial-Wave-Analyses of Reactions in a Multichannel Framework Brian Hunt Advisor: D. Mark Manley Baryons 2016, May 18, 2016, Tallahassee, FL

Outline Introduction Energy-dependent fits N*(1685) Resonance Parameters Summary and Acknowledgments

Reactions Included in the Multichannel Framework My work focuses on adding the reactions Refitting reactions Other reactions with S.E. fits – (We use SAID single-energy pion amplitudes in our fits)

Why study photoproduction reactions? Search for resonances predicted by quark models and lattice QCD Pion beams have been primary tool to study resonances What about resonances that don’t couple strongly to the channel? reactions are pure I=½ reactions Only couple to resonances Fewer parameters leads to less ambiguity

KSU Fitting Procedure Start with a single-energy fit of data Fit observables in small energy bins Generate single-energy amplitudes Fit single-energy amplitudes with energy- dependent parametrization Energy-dependent code imposes unitarity Fits all reactions with a consistent set of parameters Iterate process until a good energy-dependent fit of the observables is found

World Data Included in Fits Observable 4796 4356 879 T 334* 360 0* 239 423 88 P 7 1658 F 241* E 204* Ox and Oz 0 and 0 363 and 363 Cx and Cz 8 and 0 106 and 106 Bins With 8 independent obs 10* *Unpublished data for these observables are used in my fits, but not included in table

The following energy-dependent fits are preliminary

FIX 0 line issue, legend

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T updated 13

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P updated 15

Cx - Top Cz - Bottom updated 16

Ox – Top Oz - Bottom updated 17

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Integrated Cross Section updated

Integrated Cross Section

Integrated Cross Section updated

Integrated Cross Section updated

N(1685)* vs D15(1675) Our fits for show D15(1675) has a modest coupling to D15(1675) is predicted to have a small coupling to due to Moorhouse selection rule. Coupling of D15(1675) to is significant in the reaction data allows for resonance width of ~130 MeV Preliminary fits to data for the reaction show interpreting N(1685) with D15(1675) is reasonable 26

D15(1675) 1671 131 Added new slide Group Mass (MeV) KSU BnGa 1664 152 SAID 1674 147 Shklyar 1666 148 PDG 1670-1680 130-165 Added new slide

S11 UPDATED 5/6/2016 Figures and parameters S11(1535) and S11(1650) KSU BnGa SAID PDG Mass (MeV) S11(1535) Width (MeV) S11(1535) 1530 173 1519 5 128 14 1547 0.7 188.4 3.8 1525-1545 125-175 Mass (MeV) S11(1650) Width (MeV) S11(1650) 1665 157 1651 6 104 14 1634.7 1.1 115.4 2.8 1645-1670 110-170

S11 S11(1535) UPDATED 5/6/2016 Figures and parameters S11(1650) 8.3 Br. Ratio % KSU BnGa SAID PDG 34 54 5 35.5 0.2 35-55 57 33 5 N/A 32-52 A1/2 p 0.117 0.105 0.010 0.128 0.004 0.115 0.015 A1/2 n -0.054 -0.093 0.011 -0.075 0.020 56 51 4 100 50-70 0.1 18 4 5-15 8.3 10 5 2.5-3.4 S11(1535) UPDATED 5/6/2016 Figures and parameters S11(1650)

P13 Updated 5/6/2016 – Figures and parameters P13(1720) and P13(1900) KSU BnGa SAID PDG Mass (MeV) P13(1720) 1721 1690 70 -35 1763.8 0.7 1700 - 1750 Width (MeV) P13(1720) 145 420 100 210 22 150 400 Mass (MeV) P13(1900) 1922 1905 30 N/A 1900 30 Width (MeV) P13(1900) 362 250 +120 -50 200 50

P13 UPDATED 5/6/2016 – Figures and parameter values 16.8 16 5 Br. Ratio % KSU BnGa SAID PDG 19 10 5 9.4 .5 8-14 3.5 3 2 N/A 0.6 – 3.5 4.7 4-4.8 3.7 3 2 ~5 13.3 10 4 ~12 16.8 16 5 0 - 10 P13(1720) P13(1900)

Resonances Included in Fits S11 - 1530, 1665, 1940, 2200 MeV P11 - 1419, 1681, 1940, 2250 MeV P13 - 1720, 1922, 2240 MeV D13 - 1517, 1664, 1915, 2220 MeV D15 – 1671, 2080 MeV F15 – 1683, 1900, 2250 MeV F17, G17, G19 - 2010, 2150, 2230 MeV, respectively Compared to pdg: extra S11 2200/

Summary D15 is a viable candidate for the bump in eta photoproduction on the neutron Bump can be fitted using a resonance as wide as maybe 140 MeV, with 131 MeV our current value Missing resonances problem is still an open question Only resonance in our fits not found in PDG is a 4th S11 resonance around 2200 MeV. Where possible, we currently analyze single-energy fits up to 2250 MeV due to additional high-energy data in multiple reactions

Acknowledgments This material is based upon work supported in part by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Award Numbers DE-FG02-01-ER41194 and DE-SC0014323 Thanks to Kent State University Physics Department for partial support of my research