CLAS Hadron Spectroscopy

Working Group Meeting Report,CLAS12 2nd European Workshop/

CLAS Collaboration Meeting,March 2011

Analyses Under Working-group Review - 1

Measurement of the Lineshape, Differential Photoproduction Cross Section, Spin and Parity of the Lambda(1405) Using CLAS at Jefferson Lab Contact persons: Reinhard Schumacher, Kei MoriyaAnalysis Review Committee: Paul Eugenio (chair), Raffaella De Vita, Mac Mestayer Committee formed November 8, 2010 First round comments; awaiting author response

Photoproduction of the phi(1020) with linearly polarized photons from the proton Contact persons: Julian Salamanca and Phil ColeAnalysis Review Committee: Bryan McKinnon (chair), Pawel Nadel-Turonski, Mike Wood Committee formed June 10, 2010 Second round comments; awaiting author response

Differential cross sections and SDME for phi(1020) photoproduction from g11 Contact persons (CMU): Biplab Dey and Curtis MeyerContact persons (ODU): Heghine Seradaryan and Moskov AmarianAnalysis Review Committee: Lei Guo (chair), Raffaellla DeVita, Michael Dugger, Valery KubarovskyCommittee formed July 20, 2010 Awaiting confirmation of consistent results

Analyses Under Working-group Review – 2

Review #4709539: "Photo-production of Σ +(1385) with CLAS" (1st round ended on March 4, 2011)∗Initiated by: David IrelandReview type: AnalysisStatus: Contact author: Gagik GavalianExperiment/Working group: g11/HSCommittee: Kenneth Hicks (Chair), Ralf Gothe , Eugene Pasyuk Review deadline: March 4, 2011

Pending Analyses Reviews

Photoproduction of Lambda1520 Hyperon off Protons and Neutrons in Deuterium" with eg3 data. Contact author: Zhiwen ZhaoAwaiting formation of committee

Ad-Hoc ReviewsReview #8061056: "Upper limits for photoproduction cross section for the Φ--(1860) pentaquark state" (1st round ended on January 31, 2011)Initiated by: Hovanes EgiyanReview type: Ad-hocStatus: 1st round endedContact author: Hovanes EgiyanExperiment/Working group: eg3/HSCommittee: Reinhard Schumacher (Chair), Angela Biselli , Gerard Gilfoyle Review deadline: January 31, 2011

PAC ProposalsMeson Spectroscopy with low Q2 electron scattering in CLAS12Contact persons: Marco Battaglieri and Raffaella De VitaAnalysis Review Committee: Volker Crede (chair), Chaden Djalili, Hovanes Egiyan

PAC result: A-

Collaboration-wide reviewReview #5573944: "Electromagnetic decay of the Sigma*0 to Lambda gamma" (Ended on March 1, 2011)Initiated by: Marco RipaniReview type: Collaboration-wideStatus: EndedContact author: Kenneth HicksExperiment/Working group: g11/HSReview deadline: March 1, 2011

Agenda14:15 Opening comments - Dave Ireland14:20 Measuring the G polarisation observable for KΛ photoproduction from g9a - Stuart Fegan14:45 Search for Missing Resonances in γp -> K Λ using Circularly Polarized Photons on a Polarized Target - Liam Casey15:10 Electroproduction of hybrid 1-+ mesons - Samuel Wallon15:35 OZI and G-parity violating decays of η' and φ mesons - Moskov Amaryan

Double Polarization Observables in gp→K+L using Circularly Polarized

Photons incident on FROST (g9a)

Liam CaseyCatholic University of America

CLAS 12 European MeetingHadron Spectroscopy Group

Missing Mass M(X) (gp→K+X)

Kaon vertex distribution determines the target of event origin.

The missing mass off the Kaon can be used to find Λ and Σ signals in both targets.

Consistency – Recoil Polarization

The recoil polarization P shows good agreement with g11 data across most of the energy range. These are typical bins. Here I calculate P in an integrated manner taking the asymmetry in protons falling above and below the reaction plane.Technically, recoil asymmetry from carbon should be subtracted.

1.4 GeV

1.5 GeV

G1C to G1C Comparison

Values of g1c analysis are rotated to primed coordinate system according to the rubric of Sandorfi.

A. M. Sandorfi et al., arXiv:1010.455v1 [nucl-th] 21 Oct 2010

1.4 GeV

1.5 GeV

Helicity Asymmetry E

E plotted for the missing D13 relevant 1.5 GeV photon energy bin

Solid blue line shows kaon-MAID Model of T. Mart. Dashed orange line is the model of B. Saghai, which includes hyperonic resonances in place of D13 and the dot-dash magenta line is the SAID based PWA of GWU.

Dilution calculated by angular bin, PT and Pγ for each kinematic bin.

Polarization Transfer Lx' and Lz'

Lx‘ and Lz’ are calculated in the same manner as the beam-recoil polarization transfer with the target polarization magnitude and direction replacing the beam circular polarization and helicity.

1.5 GeV

1.5 GeV

Rare Decays of Light Mesons in CLAS. Preliminary Results.

M.Amaryan, G.Gavalian, C.Nepali

Old Dominion University Norfolk, VA

CLAS Collaboration Meeting Paris, March 10, 2011

Missing Mass

π0

K0η

ω

We use g11 Data:3 charged track events identified as a proton and two oppositely charged pions

First Observation of G-Parity Violating Decay of φ Meson

M=1.021 GeVσ = 0.005 GeV

PDG Exp. limit Br<1.8x10-5

η‘

Φ

f1(1285)

Theory prediction:Br( ) ~3x10-7

(I.J.M.Phys. A, Vol.7, No. 20(1992), 4825)

OZI Rule Violating Decay of ϕ meson in photoproduction

ω

η

ϕη‘

η‘ ϕ

Very Different from e+e- annihilation!

First Observation of rare EM decay of η meson

(Not seen before,an upper limit is quoted in PDG.)

η

ωη’

(PDG)

reaction decay OZI violated

G-parityviolated

Br (PDG)

γp->pπ+π-η ϕ(π+π-η) (not seen before)

X <1.8x10-5

γp->pπ+π-π0 ϕ(π+π-π0) (not in γp)

X 15.3%

γp->pπ+π-γ ω(π+π-γ)(not seen before)ϕ(π+π-γ)(not seen before)

<3.6x10-3

<4.1x10-5

γp->pπ+π-π0γ η(π+π-π0γ)(not seen before) ω(ηγ) (not in γp) η‘(ωγ) (not in γp)

<5x10-4

4.6x10-4

2.75%

Summary Table