Progress on Nucleon Resonances from Partial Wave Analysis Progress on Nucleon Resonances Progress on Nucleon Resonances from from Partial Wave Analysis Partial Wave Analysis Lothar Tiator Johannes Gutenberg Universität Mainz Baryons2013, Glasgow, Scotland, June 24-28, 2013
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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.
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
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.
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