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Progress on Nucleon Resonancesfrom

Partial Wave Analysis

Progress on Nucleon ResonancesProgress on Nucleon Resonancesfromfrom

Partial Wave AnalysisPartial Wave Analysis

Lothar TiatorJohannes Gutenberg Universität Mainz

Baryons2013, Glasgow, Scotland, June 24-28, 2013

theoreticaltheoretical polespoles and experimental and experimental bumpsbumps

poles in thecomplex plane

bumps on thephysical axis

WW

WW

new in PDG 2012new in PDG 2012old names new names

more focus on resonance poles and pole parametersBreit-Wigner masses, widths and branching ratios will remain, but reduced in amount.

allall BW BW parametersparameters areare modelmodel dependentdependent!!

BW parameters are background subtracted amplitudesat somewhat arbitrary positions W = MBW on the physical axis

pole parameters are residues at the pole position W = Mpole – i/2 polein the complex region on the first unphysical sheet

for some resonances, the extrapolation into the lower complex half-planeproduces larger systematic errors than the model errors of BW parameters

more focus on pole parameters in PDG2012

N(1520) ELASTIC POLE RESIDUEModulusPhase

N(1520) INELASTIC POLE RESIDUESNormalized Residues for N -> Hadronsbranchings at the pole position

N(1520) BRANCHING RATIOSconventional branchings at the BW position

N(1520) PHOTON DECAY AMPLITUDEShelicity amplitudes A1/2 and A3/2

real values at the BW position

complex values at the pole position

(examples will be shown)

see also Ron Workman on Tuesday 2pm

status of status of resonancesresonances

red : 4-star

blue : new, upgradedor renamed

mainly fromkaon photoproduction

from BES-IIIJ

J

status of status of resonancesresonances

but many uncertain stateswith less than 3-stars

no changesno new states

upgraded upgraded (1900)(1900) 3/23/2++ resonance from resonance from pp

from V. Burkert (JLab), NSTAR2013: confirmed in different analysesclose to a four-star rating

new new resonances from resonances from JJandand ’’ decaysdecaysfrom Y. Liang (BES-III), NSTAR2013:

2 new states observed: N(2300) 1/2 N(2570) 5/2

N(2300)

N(2570)

reactions with reactions with ** excitationexcitation most important channel, but only few new data since 1990

most of the resonances were found in this channel

important channels for branching ratiosand for resonances weakly coupled to

most important channel for photon couplings to p and nwill become important for more accurate pole positions

‘ very important channels for new discoveriesof resonances weakly coupled to

JNNNNNN... very important mechanism for new discoveriesisospin filter , no excitations

ppNNpppp‘ channels involving NN interaction, more difficult analysisused in combined analysis

ppNNNNNN... future potential with PANDA

PWA groupsPWA groups

SAID model indep. single ch. PWA

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

BnGa multichannel partial wave analysis,

http://pwa.hiskp.uni-bonn.de/

MAID unitary isobar model, single ch. http://www.kph.uni-mainz.de/MAID/

DMT dynamical model with few coupled channels, http://www.kph.uni-mainz.de/MAID/

Jülich dynamical model with coupled ch.,

Gießen coupled ch. unitary Lagrangian model,

Kent State K matrix coupled channels,

ANL-Osaka dynamical model with coupled ch.,

comparison of pole parameters from PWA groups

SAID 2006:Arndt, Briscoe, Strakovsky, Workman, Phys. Rev. C 74, 045205 (2006)

DMT 2007:Chen, Kamalov, Yang, Drechsel, Tiator, Phys. Rev. C 76, 035206 (2007)

BNGA 2012:Anisovich, Beck, Klempt, Nikonov, Sarantsev, Thoma, Eur. Phys. J. A 48, 15 (2012)

Jülich 2013:Rönchen, Döring, Huang, Haberzettl, Haidenbauer, Hanhart, Krewald, Meißner, Nakayama,Eur. Phys. J. A 49, 44 (2013)

ANL-Osaka 2013:Kamano, Nakamura, Lee, Sato, arXiv:1305.4351 (2013)

KSU 2012:Shrestha, Manley, Phys. Rev. C 86, 055203 (2012)

Gießen 2013:Shklyar, Lenske, Mosel, Phys. Rev. C 87, 015201 (2013)

pole positions for selected resonancespole positions for selected resonances

consistent analysisonly for

4-star resonances

some larger deviationsobserved in

ANL-Osaka analysis

3*,2*,1* res.show a large spread

in their pole positions

a more sophisticatederror analysis

in PWA is demanded

elastic residues for selected resonanceselastic residues for selected resonances

elastic residues for selected resonanceselastic residues for selected resonances

N(1535) is very unclearAO ~4 times SAID/Jü/DMT

Jülich analysis A/Ba bit off for Roperand even for

PDG average

and bands with larger rangeof b.g. phases

photon decay amplitudes for selected resonancesphoton decay amplitudes for selected resonances

photon decay amplitudes for selected resonancesphoton decay amplitudes for selected resonances

from pole to from pole to BreitBreit--WignerWigner

in approximation one can relate pole and BW parametersthis works surprisingly well for many 4* resonancesbut can fail dramatically for states with large residue phases

unitary pole Ansatz:

Breit-Wigner form: (numerator is real!)

very good

very good

very goodvery good

fails

fails dramatically

good

good

fails

ok

also recently discussed in a preprint by S. Ceci, M. Korolija, B. Zauner, arXiv:1302.3491

works well forsmall phases

( small background )

photo and electroproduction of nucleon resonances

while hardly any improvement on the hadronic database is not in sight

the data from e.m. resonance production is now gushing out from labs at Mainz, Bonn, Jlab

from A. Sarantsev, NSTAR2013 (Bonn data):

photoproduction of nucleon resonances

from M. Ostrick, NSTAR2013 (Mainz data):

photoproduction of nucleon resonances

p p

from V. Burkert, NSTAR2013 (JLab data):

1965 MeV

2169 MeV

2035 MeV

photoproduction of nucleon resonances

16 spin observables in photoproduction

linear and circular polarized beams

longitudinal and transverse polarized targets

recoil polarization, in particular for and

8 observ. 12 observ.

closer look in the partial wave amplitudes (photoproduction multipoles)

shows large differences among the different analyses,

which use mainly the same data from the world data base CNS-DAC @ GWU

strong model dependence in the pw amplitudes

due to an incomplete data base:

mainly d/d and , some T, P, very few G, H

limitedlimited datadata basebase --> > modelmodel dependentdependent PWAPWA

currently in CNS-DAC data base for p p for W< 2 GeV:dd 9798 G 28 Ox‘ 7 Tx‘ 0 2038 H 24 Oz‘ 7 Tz‘ 0T 353 E 0 Cx‘ 0 Lx‘ 0P 556 F 0 Cz‘ 0 Lz' 0

from Anisovich et al., Eur. Phys. J. A. 44, 203-220

no problems for

Re Re

ReRe

surprisingly large differences, even though the world data is equally well described

due to an incomplete data base

real parts of multipoles

comparisoncomparison of of multipolesmultipoles: MAID : MAID –– SAID SAID -- BNGABNGA

with each newly measured polarization observables we can hope

to improve the partial wave analysis

there is a systematic way to go: thethe completecomplete experimentexperiment

for pesudoscalar meson photoproduction 8 well selected observables(with beam, target and recoil polarization required) are needed to predict all other experiments

and to determine the 4 underlying complex amplitudesup to an overall (energy and angle dependent) phase.

the complete experiment

studies on the complete experiment

• Barker, Donnachie, Storrow, Nucl. Phys. B95 (1975) 347-356• Fasano, Tabakin, Saghai, Phys. Rev. C46 (1992) 2430-2455• Keaton, Workman, Phys. Rev. C53 (1996) 1434-1435• Chiang, Tabakin, Phys. Rev. C55 (1997) 2054-2066

earlier studies on the complete amplitude analysis

recent studies on PWA from complete experiments

• Workman, Paris, Briscoe, Tiator, Schumann, Ostrick, Kamalov, Eur. Phys. J. A 47 (2011) 143

• Sandorfi, Hoblit, Kamano, Lee, J. Phys. G38 (2011) 053001• Dey, McCracken, Ireland, Meyer, Phys. Rev. C83 (2011) 055208• Wunderlich, Diploma Thesis, Bonn 2012

recent studies on the complete amplitude analysis• Ireland, Phys. Rev. C82, 025204 (2010) • Vrancx, Ryckebusch,Van Cuyck, Vancraeyveld, Phys. Rev. C87, 055205 (2013)

target-recoil

beam-recoil

beam-target

single

Lz´Lx´Tz´Tx´TR

Cz´Cx´Oz´Ox´BR

FEHGBT

PTd/dS

observablesset

Keaton, Workman (1996) and Chiang,Tabakin (1997):

a carefully chosen set of 8 observables is sufficient.

requirementsrequirements forfor a a completecomplete experimentexperiment in in photoproductionphotoproduction

set observables

single S dd T Pbeam-target BT G H E F

beam-recoil BR Ox´ Oz´ Cx´ Cz´

target-recoil TR Tx´ Tz´ Lx´ Lz´

choosechoose anyany 8 out of 16 8 out of 16 observablesobservablesthisthis setset doesdoes notnot workwork!!

set observables

single S d/d T Pbeam-target BT G H E F

beam-recoil BR Ox´ Oz´ Cx´ Cz´

target-recoil TR Tx´ Tz´ Lx´ Lz´

choosechoose anyany 8 out of 16 8 out of 16 observablesobservables

thisthis setset worksworks!!

it is shown that very high statistics were neededor an overcomplete experiment with 10 or more observables !

•from information entropy D. Ireland (Glasgow, 2010)

• in simulations with pseudo data S. Schumann et al. (Mainz, 2011)

• in first analysis with real data T. Vrancx et al. (Ghent, 2013)

the overall phase problem:

However, from this kind of analysis one gets only

the 4 so-called „reduced“ amplitudes and no partial waves!

because for the partial wave projection one needs the „full“ amplitudes

this phase cannot be measured

and can also not be calculated by unitarity constraints

mathematical studies:

Omelaenko (1981)for a truncated partial wave analysis (TPWA) with lmax waves only 5 observablesare necessary, e.g. the 4 from group S and 1 additional from any other group

Wunderlich (Bonn, 2012)revisited Omelaenko formalism for lmax =2 and 3the need for only 5 observables is confirmed, but with rising lmax,large amount of accidental ambiguities will appear, making numerical analysis difficult

requirementsrequirements forfor a a completecomplete experimentexperiment forfor TPWATPWA

experimental applications:

Grushin (1989)applied it for a PWA in the (1232) regionwith only S+P waves(lmax = 1

present activitiesin Mainz, Bonn, JLab

complete and overcomplete analysis

results of a

truncated partial

wave analysis with

Lmax=3

of the MAID pseudo

data

performed in

collaboration with

SAID group

Workman, Paris, Briscoe,

Schumann, Ostrick,

Tiator, Kamalov,

Eur. Phys. J. A47, 143 (2011)

The L+P (The L+P (Laurent+PietarinenLaurent+Pietarinen) expansion method is defined as:) expansion method is defined as:

NucleonNucleon ResonanceResonance Analysis Analysis withwith PietarinenPietarinen expansionexpansionin collaboration with Svarc (Zagreb), Osmanovic et al (Tuzla), Workman (GWU)

applications and publications in progress:

• on elastic with comparison of toy model, SAID and DMT analysis

• on photoproduction with ED and SE solutions of SAID and MAID

• on new pol. data towards the complete experiment with MAMI data

talk on Tuesday 2pm

L+P L+P expansionexpansion of MAID SE and ED of MAID SE and ED solutionssolutions

MAID energy-dependent solution (ED)

MAID single-energy solution (SE)

for ED solutions, L+P expansiongives a numerical approximation ~ 10-3

for SE solutions, L+P expansiongives the best-fit with a statistically significant 2 ~ 1

P11(1710)is not included in MAIDit is found in the L+P expansion ofthe MAID single-energy analysis

L+P L+P expansionexpansion of MAID SE and ED of MAID SE and ED solutionssolutions

MAID energy-dependent solution (ED)

summarysummary and and conclusionconclusion

• Pole Positions and Residues are fundamental resonance propertiesBreit-Wigner parameters are convenient but model dependentthis has become common knowledge in the communityand is now beeing considered also in the PDG

• Dynamical coupled channels PWA is most sophisticated andphotoproduction has to be fully integrated

• Data with unprecedented precison is coming from mesonphotoproduction in complete experiments

• It will lead to more accurate resonance propertiesand discoveries or establishements of new resonances

from Mike Pennington

about the new Baryons@PDG team

Baryons@PDG

Baryons

PARTICLE PHYSICSBOOKLET

2014

Light Baryon Section

The Team

Tiator Wohl Workman

Burkert Klempt Pennington

the idea is to make more data

on Light Baryons accessible

outside of PDG

Aim to form a publicly accessible web-base archiving/updating

The full range of data on cross-sections and polarization asymmetries measured in hadro and photo-production of hadron resonances

For each N* its mass, width, and all decay couplings

Transition form-factors for excited N*’s

For each analysis, the partial wave amplitudes in which these excited hadrons occur

a graphical representation of the dataa graphical comparison of the partial waves in each analysisa detailed exposition of the methods used in each analysis

Where appropriate to be compared with the detailed predictions of QCD

Synergy with PDG

PDG inputs would link to this broader information

longer term

traditional Particle Data Listingsremains in Review and Booklet