SAID Facility and Database Development - CNS DAC Services ...

SAID Facility and Database Development 

Igor Strakovsky 

The George Washington University 

� Critical role of the pN analysis 

� Non-strange Resonances with I = 1/2 and 3/2 

� Recent gn�pN data and Multipole fits 

� JLab effort in g * N�pN 

� Summary and Prospects 

5/23/2011 

PWA2011 Workshop, Washington, DC, May 2011 

Igor Strakovsky 1

5/23/2011 Igor Strakovsky 2 


+

GW DAC Research is Focused on Fivefold Way 

��PWA: Partial-wave analysis of fundamental two- and three-body reactions 

��Experimental Program Support: Analysis of final and preliminary data, 

determination conflicting data, interpretation of new measurements, 

and studies of systematics and sensitivities required for the refinement 

of experimental proposals 

��Phenomenological and Theoretical Investigations: Studies which bridge the 

gap between theory and experiment, including the methodology used in 

PWA 

��Databases: Development of databases associated with the fundamental 

reactions 

��Development of the SAID Facility: Creation of new software, including 

graphical representations, to disseminate our results (and the results 

of competing analyses which have often employed different methods) 

5/23/2011 


Igor Strakovsky 3 

+

GW DAC Database Development 

��We update the SAID databases, 

develop and study PWAs, and 

keep current versions of 

phenomenological and theoretical models, 

both those of the CNS/DAC and other 

research groups, on a continual basis for 

relevant two- and three-body reactions of 

interest 

��These are made available to the nuclear and 

particle physics communities through 

web-based 

SAID: http://gwdac.phys.gwu.edu/ and 

secure-shell interfaces 

ssh –X –C said@gwdac.phys.gwu.edu [no passwd] 

to the SAID Facility 



+

SAID Database below 4 GeV 

��In the full database, one will occasionally 

find experiments which give conflicting 

results 

��Some data with very large c 2 contributions 

have been excluded from our fits 

��Redundant data are also excluded 

[these include s tot based on ds/dW 

already contained in the database] 

��Measurements of pol observables (P, 

for instance) with uncertainties 

more than 0.2 are not included as 

they have little influence in our fits 

��However, all available data have been 

retained in the database (the 

excluded data labeled as `flagged’) 

so that comparisons can be made 

through our on-line facility 

el 

31,402 

5,267 

25,660 

9,086 

1,030 

6,083 

[SAID: http://gwdac.phys.gwu.edu/] 

[W = 1320 to 1930 MeV ] 

241,214 evts+ 

For p�2p, we use log-likelihood 

while for the rest - least-squares 

technologies 

5/23/2011 



38,162 

113,900 

6,235 

1,914

Partial-Wave Analysis for N* and D* 

Originally: PWA arose as the technology to determine amplitude 

of the reaction via fitting scattering data 

[Solution of Ill-Posed Problem - Hadamard, Tikhonov, ea] 

Resonances appeared as a by-product 

That is the strategy of the GW/VPI pN PWA since 1987 

5/23/2011 



+

N* and D* States coupled to pN 

[SAID: http://gwdac.phys.gwu.edu/] 

� GW SAID N* program consists of pN�pN gN�pN g * N�pN 

As was established by Dick Arndt on 1997 

� Assuming dominance of 2-hadronic channels 

[pN elastic & p - p�hn], we parameterize 

g * N�pN in terms of pN�pN amplitudes 

� That is One of the most convincing ways to study Spectroscopy 

of N * & D * is pN PWA 

� Non-strange objects in the PDG Listings come mainly from: 

Karlsruhe-Helsinki, Carnegie-Mellon-Berkeley, and 

GW/VPI 

� The main source of EM couplings is the GW/VPI analysis 

5/23/2011 



+

Road Map for SAID Analysis of Scattering Data 

� pN PWA provides the base for Spectroscopy studies 

for non-strange baryons in all other processes 

� Our PWAs have been as model-independent as possible, so as to 

avoid bias when used 

� In resonance extraction or 

� Coupled-channel analysis 


PWA2011 Workshop, Washington, DC, May 2011

GW DAC Search for N* and D* 

� We are considering a resonance as a Pole in the complex plane which is not far away from the physical axis 

� Applied directly to the data via BW + Bckgr 

� Assume: S � S RS B S R = 1 + 2iT R 

T R = (G e/2) / [W R – W – i(G e/2 + G I/2)] 

G = G e + G I G e = r eGR G I = r iG (1 - R) 

T B = K B(1 - iK B) -1 K B = a + b(W – W R) + c 

� Map c 2 [W R,G] while searching all other PW parameters 

Look for significant improvement 

� Subjective variables are 

� Energy binning 

� Strength of constraints 

� Which PW to be searched 

� Standard PWA 

��Modified PWA 

� Tends (by construction) to miss narrow Resonances with G < 30 MeV 

� Reveals only wide Resonances, but not too wide [G < 500 MeV] 

and possessing not too small BR [BR > 0.04] 

� Allows to put a resonance by hands 

Then the search will allow to see how reliable/tolerable it is 



GW DAC for pN�pN & p - p�hn 

[R. Arndt, W. Briscoe, IS, R. Workman, Phys Rev C 74, 045205 (2006)] 

� Energy dependent SP06/WI08 and associated SES 

� T = 0 – 2600 MeV [W = 1078 – 2460 MeV] 

� 4-channel Chew-Mandelstam K-matrix parameterization [pN, pD, rN, hN] 

� 3 mapping variables: g 2 /4p, a[p - p], Eth 

� PWs = 30 pN {15 [I=1/2] + 15 [I=3/2]} + 4 hN [l < 9] 

� Prms = 99 [I=1/2] + 89 [I=3/2] 

��1st generation ('57-'79) 

Used by CMB79 and KH84 analyses 

10k p � p each & 1.5k CXS 

17% data is polarized 

��2nd generation ('80-'06) 

�SAID fits 

13k p � p each, 3k CXS & 0.3k p - p�hn 


Meson Factories [LAMPF, TRIUMF, & 

PSI] are the main source of new 

measurements 

There is no discrimination against data 

��3rd generation (06'+) 

New data may come from 

J-PARC, GSI, FNAL MIPP, etc 

5/23/2011 

Reaction Data c 2 

p + p�p + p 13,354 27,136 

p - p�p - p 11,978 22,632 

p - p�p 0 n 3,115 6,068 

p - p�hn 257 650 

DR constraint 2,775 671 

Total 31,479 57,157 

DRs have been derived 

from the first principles 


}[0 – 2600 MeV] � 10 data/MeV 

[550 – 800 MeV] � 1 data/MeV 

27 s tot and 37 P data 

above 800 MeV � 0.03 data/MeV 

Igor Strakovsky 10

ds/dW (mb/sr) 

p - p�hn Puzzle 


[Brown et al, Nucl Phys B153, 89 (1979)] 

[Feltesse et al, Nucl Phys B93, 242 (1975)] 

5/23/2011 

W = 1572 MeV 

q = 160 deg 

W = 1601 MeV 

� Several groups evaluated data before 1992 

Clajus & Nefkens, pN News Lett 7, 76 (1992) 

Cutkosky et al Phys Rev D 20, 2804 (1979) 

Koch & Pietarinen, Nucl Phys A336, 331 (1980) 

Wighman et al Phys Rev D 38, 3365 (1988) 

[Debenham et al, Phys Rev D 12, 2545 (1975)] 

Nimrod was a 7 GeV proton synchrotron 

operating in the Rutherford Appleton 

Laboratory in UK between 1964 and 1978 

� Most of Nimrod data do not satisfy requirements 

[systematics (10% or more), momentum err (up to 50 MeV/c), and so on] 

� For that reason, we are not able to use them in p - p�p - p, p 0 n, and hn PWAs 


Igor Strakovsky 11

N(2090)* 

N(1710)*** 

SP06 

Partial Waves [L (2I)(2J)] 


� Overall: the difference between KH and GW/VPI is rather small but… 

resonances may be essentially different 

N(2100)* 

ImT 

D(1600)*** 

ReT 

KA84 

SP06-SES 

ImT-T * T � 0 [unitarity boundary] 

PDG10 [K. Nakamura et al [RPP] J Phys G 37, 075021 (2010)] 

KA84 [R. Koch, Z Phys C 29, 597 (1985)] 

D(1920)*** 

� Old solutions may be not able to 

reproduce new measurements 

1300 MeV 

P 2 + R 2 + A 2 = 1 

Data: 

ITEP: p + p�p + p @ 1300 MeV 

[I.G. Alekseev et al Phys Lett B 351, 585 (1995)] 

PWA: 

KA84: Karlsruhe-Helsinki fit, 1984 

KB84: KH Barrelet corrected solution, 1997 

SP06: GW fit, 2006 

I. Alekseev et al Phys Rev C 55, 2049 (1997) 

5/23/2011 


Igor Strakovsky 12

Summary of N* and D* Finding from GW pN PWA 


� PDG10 states 

� Standard PWA 

� Allows to determine the N * s, D * s, and their quantum numbers using 

� The complex energy plane and 

� Breit-Wigner technique 

� Tends (by construction) to miss narrow Resonances with G < 30 MeV 

� Reveals only wide Resonances, but not too wide (G < 500 MeV) and 

possessing not too small BR (BR > 4%) 

The latest GWU analysis (Arndt06) finds no evidence for those resonances 

PDG10 *** D(1600)P 33, N(1700)D 13, N(1710)P 11, D(1920)P 33 

PDG10 ** N(1900)P 13, D(1900)S 31, N(1990)F 17, D(2000)F 35, 

N(2080)D 13, N(2200)D 15, D(2300)H 39, D(2750)I 313 

PDG10 * D(1750)P 31, D(1940)D 33, N(2090)S 11, N(2100)P 11, 

D(2150)S 31, D(2200)G 37, D(2350)D 35, D(2390)F 37 

� Our study does suggest several ‘new’ N*s and D*s: 

PDG10 **** D(2420)H 311 

PDG10 *** D(1930)D 35 

PDG10 ** N(2000)F 15, D(2400)G 39 

PDG10 new N(2245)H 111 



SAID for Pion Photoproduction 

[M. Dugger et al Phys Rev C 79, 065206 (2009) G. Mandaglio et al Phys Rev C 82, 045209 (2010)] 


� Energy dependent SP09/MA09 and associated SES 

� E = 145 – 2700 MeV [W = 1080 – 2460 MeV] 

� PWs = 60 [E & M multipoles] [J < 6] 

� Prms = 210 

� Constraint: M = (Born + a R)(1 + iT pN) + aRT pN + higher terms 

Reaction Data (Dpol) c 2 

gp�p 0 p 14,052 (3 %) 30,949 

gp�p + n 8,510 (5 %) 16,240 

gn�p - p 2,432 (0 %) 5,248 

gn�p 0 n 364 (0 %) 1,021 

Total 25,358 53,458 

N(gn) = 0.12*N(gp) 

��1st generation - (‘60-‘90) 

10k data [85% bremsstrahlung data] 


[limited coverage, broad energy binning] 

��2nd generation ('90-'10) � SAID fits 

Much less known 

25k data [60% tagged data] 


Dearth of neutron data 

��3rd generation ('10+) 

New data will come from JLab, MAMI-C, 

Spring-8, CB-ELSA, MAX-lab, etc 

5/23/2011 


Born: no free parameters to fit 

pN PWA [no theoretical input] 

Igor Strakovsky 14

Proton Multipoles for SP09 [CLAS p 0 p & p + n data included] 

[M. Dugger et al Phys Rev C 79, 065206 (2009)] 

SP09 

� Overall: the difference between MAID07 and SAID SP09 is rather small but… 

Resonances may be essentially different 

S 11 

A 1/2 = 100.9�3.0 [66] 

A 1/2 = 9.0�9.1 [33] 

MAID07 

S 31 

A 1/2 = 47.2�2.3 [66] 

P 11 

A 1/2 = -56.4�1.7 [-61] 

BW for pN SP06 

P 33 

A 1/2 = -139.6�1.8 [-140] 

A 3/2 = -258.9�2.3 [-265] 

� MAID07 does not include recent CLAS p 0 p & p + n and LEPS p 0 p data 

� MAID Ansatz has been used to 

determine EM couplings 

� The statistical significance of any 

inconsistencies with the MAID 

analysis cannot be determined, 

as no uncertainties for photon 

helicity amplitudes estimation 

have been presented 

� Significant changes have occurred 

at high energies 

� Comparisons to earlier SAID fits 

and fit from the Mainz group show 

that the new SP09 solution is much 

more satisfactory at higher energies 

MAID07: D. Drechsel et al Eur Phys J A 34, 69 (2007) 

5/23/2011 


Igor Strakovsky 15

CLAS for gn�p - p 

[g10: W. Chen et al Phys Rev Lett 103, 012301 (2009) g13: P. Mattione et al in progress] 

� Complementary measurements of p - Photo Production, 

required for an isospin decomposition of the multipoles 

PWA/Model: 

____ FA07 [No CLAS p - ] 

____ MAID07 [No CLAS p - ] 

____ WE09 [CLAS p - is in] 

5/23/2011 

CLAS g10: 850 ds/dW 

E g =1050–3500 MeV 

q = 37– 152 deg 

Stat = 3 % 

Syst = 7 % 


� Principal p - experiments were done 

at Meson Factories: LAMPF, PSI, & 

TRIUMF 

[Courtesy of Paul Mattione, CLAS Meeting 2010] 

��No FSI included in both CLAS 

g10 & g13 [2% of statistics] data 

��G13 vs g10: 

��broad angular coverage 

��smaller errs 

��smaller energy binning 

Igor Strakovsky 16

5/23/2011 

FSI for gn�p - p 

[V. Tarasov, A. Kudryavtsev, W. Briscoe, H. Gao, IS, arXiv: 1105.0225] 

� FSI plays a critical role in the state-of-the-art analysis 

��Effect: 5% – 60% It depends on E and q 

Input: SAID gN�pN, pN, NN amplitudes 

for 3 leading terms 

DWF: CD-Bonn 

IA 

� 


Fermi motion included 

pN-fsi 

vertex 

NN-fsi 

vertex 

Igor Strakovsky 17

FSI & gd�p - pp gn�p - p 

[V. Tarasov, A. Kudryavtsev, W. Briscoe, H. Gao, IS, arXiv: 1105.0225] 

gd�p - pp - No fit to the data 

DESY [Bubble Chamber data]: 

P. Benz ea Nucl Phys B65, 158 (1973) 

5/23/2011 

q(pg-LS) 

….. IA 

- - - IA + NN fsi 

___ IA + (NN+pN) fsi 

-- - [IA + NN fsi] / IA 

___ [IA + (NN+pN) fsi] / IA 

. 

gn�p - p 


. 

There is a sizeable 

FSI effect R < 1 from 

S- wave part of pp- 

FSI at small angles 

This region narrows 

as the E g increases 

gn�p - p 

q(pp-CM) 

Cuts: 

p s > 200 MeV/c 

p f > 200 MeV/c 

Igor Strakovsky 18

New GRAAL S for gn�p 0 n 

[R. Di Salvo et al Eur Phys J A 42, 151 (2009)] 

� The difference between previous Pion Prod and new GRAAL 

measurements may result in significant changes in the 

neutron couplings 

c 2 /dp 

MAID07 100 

SP09 223 

MA09 3.1 

No FSI included 

��216 GRAAL Ss 

are 60% of the 

World p 0 n data 



� 

. 

GRAAL data are in

New GRAAL S for gn�p - p 

[G. Mandaglio et al Phys Rev C 82, 045209 (2010)] 

� Previous gn�p - p measurements provided a better constraint 

vs gn�p 0 n case 

No FSI included 



� 

c 2 /dp 

MAID07 27 

SP09 89 

MA09 4.9 

. 

GRAAL data are in

Neutron Multipoles for MA09 [GRAAL p 0 n & p - p data included] 


� Overall: the difference between MAID07 and SAID MA09 is rather small but… 

Resonances may be essentially different 

S 11 

P 13 

GRAAL data are in 

5/23/2011 



P 11 

F 15 


D 13 

D 15

E 0+ Neutron Multipole 



GRAAL data are in 

S 11 

[R. Di Salvo et al Eur Phys J A 42, 151 (2009)] 

5/23/2011 



Im 

Re 

h-cusp is visible for MA09 

Modified 

MAID07 

MAID07

S 

Backward gn�p - p 

1179 new S vs. 167 ! [That is 50% of World p - p data] 

� No FSI included 

5/23/2011 

5/23/2011 



� 

.

� No FSI included 

Forward gn�p - p 


5/23/2011 


24 

� 

.

FSI for Polarized Measurements 

��There were several attempts to estimate FSI for gd�p- � 

pp 

FSI: M. Levchuk ea Phys Rev C 74, 014004 (2006) 

Data: prlm by LEGS Collab at BNL 

��There are no estimations below and above the D-region 

��The effect from FSI is small and at lowest energies 

has a noticeable impact on S 



Coming p and h Photo Prod Data on Nucleon 

On Proton: 

On Neutron: 

FSI is critical to determine 

Neutron Multipoles 

5/23/2011 

Mike Dugger, ASU: - CLAS g8b: S for gp�p + n, p 0 p 

Patrick Collins, ACU: - CLAS g8b: S for gp�hp 

Hideko Iwamoto & Bill Briscoe, GW: - CLAS g9a: E for gp�p 0 p 

Steffen Strauch, USC: - CLAS g9a: E for gp�p + n 

Brian Vernarsky & Mike Dugger, ASU: - CLAS g9a: E & G for gp�hp 

Jo McAndrew & Dan Watts, EU: - CLAS g9a: G for gp�p + n, p 0 p 

Wei Chen & Haiyan Gao, Duke U: - CLAS g12: ds/dW for gp�p + n 

Arthur Sabintsev & Bill Briscoe, GW: - CLAS g9b: T, H, F, & P for gp�p + n 

Steffen Strauch, USC: - CLAS g9b: T, H, F, & P for gp�p 0 p 

Reinhard Beck, Bonn U: - CB-ELSA: S, E, G, & T for gp�p 0 p, hp 

Wei Luo & Charles Perdrisat, W&M - Hall C: C x, C z & P for gp�p 0 p 

Derek Glazier & Dan Watts, EU: - MAMI-C : P & C x for gp�p 0 p,hp 

Viktor Kashevarov , INP: - CB@MAMI-C: F & T for gp�p 0 p, hp 

Kevin Fissum, Lund U/GW: - MAX-lab: s-tot for gp�p + n 

Andy Sandorfi, JLab: - LEGS: E & G for gp�p 0 p, p + n 

David Hornidge, MTA & Sergey Prakhov, UCLA: - CB@MAMI-C: ds/dW & S for gp�p 0 p 

Wei Chen & Haiyan Gao, Duke U: - CLAS g10: ds/dW for gn�p - p 

Daria Sokhan & Dan Watts, EU: - CLAS g13: S for gn�p - p 

Paul Mattione & Dan Carman, JLab: - CLAS g13: ds/dW for gn�p - p 

Andy Sandorfi, JLab & Franz Klein, ACU: - CLAS g14: E for gn�p - p 

Berhan Demissie & Bill Briscoe, GW: - CB@MAMI-C: ds/dW for gn�p 0 n 

Berndt Krusche, Basel U: - CB@MAMI-C: ds/dW & S for gn�hn 

Berndt Krusche, Basel U: - CB-ELSA: E for gn�hn 

Kevin Fissum, Lund U/GW & Bill Briscoe, GW: - MAX-lab: ds/dW for gn�p - p, p 0 n 

Hajime Shimizu, Tahoku U: - LNS: ds/dW for gn�hn 

Andy Sandorfi, JLab: - LEGS: E & G for gn�p - p, p 0 n 


Igor Strakovsky 26

GW DAC for Pion Electro Prod 

� Energy dependent SM08 and associated SES & SQS 

� W = 1080 – 2000 MeV Q2 = 0 – 6 GeV2 � PWs = 60 [multipoles] [J < 6] 

� Prms = 171 

� Constraint: pN + Pion Photo Prod PWAs [no theoretical input] 

� 0.85 World Electro Prod = JLab CLAS { 

� PWA Problems: 

� Additional [S] Multipoles 

� Q 2 dependence 

� Database Problems: 

� Most of data are unPolarized 

measurements 

� There are no p 0 n data and 

very few p - p [no Pol measurements] 

That does not allow to 

determine n-couplings at Q 2 > 0 

{ 

Reaction Data c 2 

g * p�p 0 p 55,766 81,284 

g * p�p + n 51,312 80,004 

Redundant 14,772 17,375 

Total 121,850 178,663 

gN�pN 25,358 53,458 

All Photo* 147,208 232,121 

pN�pN 31,479 57,157 

All pN 178,687 289,278 

g * n�p - p 801 

g * n�p 0 n No Data 

Q 2 -Data 

New CLAS data 

are coming 

5/23/2011 


Igor Strakovsky 27

� Where we are now 

Summary and Prospects 

� pN analysis is crucial for the N* program 

� Extended pN elastic and Pion Prod analyses are done up to W = 2.5 GeV 

��pN�hN and Eta Photo Prod analyses are done up to W = 1.65 GeV 

� What we have to do 

�� JLab FROST & HD-ICE, CB@MAMI-C, LEPS, CB-ELSA, & MAX-lab data could yield 

surprises 

� Prod measurements on the `neutron’ target are necessary to determine neutron 

couplings at Q 2 = 0 GeV 2 

� Complete experiment would make possible a direct reconstruction of helicity 

amplitudes for PseudoScalar meson Photo Prod 

� Proton Electro Prod PWA is included 125k data up to W = 2 GeV and Q 2 = 6 GeV 2 

� What to Expect when we are Expecting 

� Q 2 evaluation of Resonance couplings up to very large Q 2 

� Neutron Electro Prod measurements are necessary to determine neutron couplings 

at Q 2 > 0 

��Can we reach an asymptotic regime as PQCD predicted ? 

��With JLab 12 GeV upgrade the spectroscopy program will extend to strange baryons 



. 

THANK YOU 

5/23/2011 


Igor Strakovsky 29

. 

THANK YOU 

5/23/2011 


Igor Strakovsky 30

Forward Cross-Sections for p 0 Photo Prod 


PWA/Model: 

FA07 

MAID07 [No CLAS+LEPS data in] 

Gießen [No CLAS+LEPS data in] 

BoGa [No CLAS+LEPS data in] 

� Forward [< 40 deg in CM] measurements above E = 1200 MeV 

are 5% of the world data, they are Brem, and 30 years old 

� No Forward measurements above E = 2100 MeV 

[L. Tiator, Fall 2007] 

[V. Shklyar, July 2006] 

[A. Sarantsev, Sept 2005] 

Data: Syst 

� CLAS g1c [2007] [ 5 %] 

� CB-ELSA [2005] [15 %] 

� LEPS [2007] [10 %] 

o Brem before 1977 

[No MAID07 & Gießen above 1650 MeV] 

� There is a disagreement at forward angles 

� CLAS vs CB-ELSA 

� SAID vs MAID 

� Forward data are sensitive to highest N* [most of them are inelastic] 

5/23/2011 


Igor Strakovsky 31

CLAS for gp�p + n 


� No prior comprehensive tagged p + n measurements above 800 MeV 

� Near its upper energy limit (W = 2 GeV), MAID07 exhibits structures not seen in the data 

PWA/Model: 

____ SP09 [CLAS is in] 

____ FA07 [No CLAS] 

____ MAID07 [No CLAS] 

CLAS g1c: 618 ds/dW 

Eg =725–2875 MeV 

q = 32– 148 deg 

Stat = 3 % 

Syst = 6 % 



Effect of Double-Pol Hall A data in fits to Pion Photo Prod 

[R. Arndt, IS, R. Workman, Phys Rev C 67, 048201 (2003)] 

� That is not artifact ! 

� gp�p0 � �p 

at 1900 MeV 

� DNPL: T 

[P.J. Bussey et al Nucl Phys B159, 383 (1979) plus] 

� Hall A: 22 C x, 21 C z below 2 GeV 

[K. Wijesooriya et al Phys Rev C 66, 034614 (2002)] 

� Hall A data does allow to reproduce previous DNPL 

measurements for T-asymmetry well 

��No fits, predictions only 

[Courtesy of Wei Luo, March 2011] 

5/23/2011 


Igor Strakovsky 33

CLAS S Beam Asymmetry in Pion Photo Prod 

SAID09 

MAID07 

[Courtesy of Mike Dugger, MENU2010] 

� New S for pion reactions [g8b] will overlap previous measurements 

� Above 1500 MeV, many of g8b data will be new to the world 

� � 

S S 

� CLAS E g = 1025 – 2075 MeV 

q = 46 - 134 deg 

� No fits, predictions only 

5/23/2011 


Igor Strakovsky 34

CLAS FROST for Helicity Asymmetry E for gp�p 0 n 

E 


5/23/2011 



�� 

[Courtesy of Hideko Iwamoto, Feb 2011]

CLAS FROST for Helicity Asymmetry E for gp�p + n 

E 

Circularly polarized beam – longitudinally polarized target (analysis USC) 


�� 

[Courtesy of Steffen Strauch, APS 2010] 

5/23/2011 


Igor Strakovsky 36

MAMI-B for C x - Transferred Pol from Circ Pol g: p(g,�p 0 )p 

C x 

E g=425 MeV 

Pion angle in CM (Deg) 

E g=650 MeV 

E g=975 MeV 

5/23/2011 

E g=475 MeV 

E g=750 MeV 

SP09 gives 329/63 

1x weighting for Cx* gives 187/63 

4x weighting (forced fit) gives 175/63 


E g=1225 MeV 

[Courtesy of Dan Watts, N*2009] 

E g=550 MeV 

E g=850 MeV 

� Forced Fit results indicate that 

more Pol measurements required 

for constraint of a solution 


E g=1300 MeV 

� � 

Igor Strakovsky 37

CB@MAMI-C for F & T Asymmetries for gp�p 0 n 

h-thr 

F 

T 

MAID07 

SAID09 


�� 

P 2 + S 2 + T 2 + E 2 + F 2 + G 2 = 1 

FG + ST = P + EH 

[Courtesy of Viktor Kashevarov, Feb 2011] 

5/23/2011 


Igor Strakovsky 38

LEGS @ BNL [HD-ICE Target] for E & G Asymmetries 

�� 

for gp�pN 

E 

G 

5/23/2011 

[Courtesy of Andy Sandorfi, Apr 2010] 




MAID07 

SAID09

�� 

CLAS & CB-ELSA for G Asymmetry for gp�p 0 n 

G 

[Courtesy of Jo McAndrew , CLAS Meeting 2011] 

��No fits, predictions only [Courtesy of Reinhard Beck, MENU2010] 

5/23/2011 


Igor Strakovsky 40

….. 

E429 

hMAID 

GE09 

o CB+TAPS@MAMI-C 

included 

CB@MAMI-C for gp�hp 

[E.F. McNicoll et al. Phys Rev C 82, 035208 (2010)] 

18 deg 

162 deg 

s tot 

��Our data show a dip near W = 1670 MeV in s t and its association with 

a significant dip in the forward ds/dW 

� This feature was missed or questionable in the analysis of previous data 

0 deg 

180 deg 



R EM and R SM Ratios for P 33 vs Q 2 

[R. Arndt, W. Briscoe, IS, and R. Workman, SOH, Greece, April, 2006; nucl-th/0607017] 

PQCD: R EM = +1 @ Q 2 �� 

GW: R EM = -1.79 � 0.18 % 

PQCD: R SM = 0 @ Q 2 �� 

��The question is – can Electro Prod 

experiment reach asymptotic 

regime as PQCD predicted ? 

� No recent CLAS p + and DoblP p 0 in this GW fit 

� Agreement between Lattice 

and GW looks good 

___ SP06 

� SQS 

D Lattice 

C. Alexandrou et al Phys Rev Lett 94, 

021601 (2005) 

� Large M-multipole is not 

significantly different in 

different resonance 

extractions 

� Differences for E-multipole 

are much larger 



Minimization and Normalization Factor for pN PWA [c 2 /Data] 


��Modified c 2 function, to be minimized 

Standard c 2 [UnNorm] 

Modified c 2 [Norm] 

c 2 /Data SP06 FA02 KA84 

Reaction Norm UnNorm Norm UnNorm Norm UnNorm 

p + p�p + p 2.0 6.1 2.1 8.8 5.0 24.9 

p - p�p - p 1.9 6.2 2.0 6.6 9.1 51.9 

p - p�p 0 n 2.0 4.0 1.9 5.9 4.4 8.8 

p - p�hn 2.5 9.6 2.5 10.5 

FA02 [R. Arndt ea Phys Rev C 69, 035213 (2004)] 

KA84 [R. Koch, Z Phys C 29, 597 (1985)] 

} 

� Normalization freedom provides a significant improvement 

for our best fit results, we cannot ignore exp input 

� For nonSAID, the Normalization constants were searched to 

minimize c 2 (no adjustment of the partial waves was 

possible) 

q i exp measured, ei stat error, q i calculated, 

X norm const, e X its error 

� GW solutions look realistic & stable vs previous and models 

EBAC 

Norm UnNorm 

13.1 23.7 

4.9 16.0 

3.5 6.3 

Gießen 

Norm UnNorm 

10.5 17.7 

12.1 34.1 

6.3 15.2 

SAID: W < 2500 MeV 

KA84: W < 2900 MeV 

EBAC: W < 1910 MeV 

Gießen: W < 2000 MeV 

BoGA: W < 2260 MeV 

BoGa 

Norm UnNorm 

5.7 17.8 

5.6 43.5 

3.2 8.0 

EBAC [B. Julia-Diaz ea Phys Rev C 76, 065201 (2007)] )] BoGa: [A. Sarantsev ea (2009)] 

Gießen [V. Shklyar ea Phys Rev C 71, 055206 (2005)]

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