Electromagnetic Strangeness Production, Slides of Electromagnetism and Electromagnetic Fields Theory

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May 31, 2010May 31, 2010 Williamsburg, VAWilliamsburg, VA

Electromagnetic Strangeness

Production Reinhard Schumacher

“MENU”: „ Motivation for K Y study in N* resonance physics+ „ γ^ p^ Æ^ K

Λ & γ^ p

+^0 Æ KΣ^

Cross Sections: old and new

„^ Spin Observables^ „^ P,Y^

Σ^ – single spin results: older and new „ O, O– beam-recoil: preliminary resultsxz^ „ C, C– beam-recoil: CLAS measurementsxz^ „ Electroproduction extension…

„^ Λ(1405) mass distribution

Å^ Recent New Result

„^ Likely signature of non-qqq structure0,−(*)^ „ Ξproduction: search for resonances „ Future prospects „^ CLAS g13 data set,

(^0) γ n Æ K (^0) Λ,Σ cross sections

„^ FROST & HD Ice targets May-31-2010, MENU^

R. A. Schumacher, Carnegie Mellon University

The “Missing Baryon” (N*) Problem May-31-2010, MENU^

R. A. Schumacher, Carnegie Mellon University Center of mass energy of baryonic system S. Capstick and W. Roberts, Phys. Rev. D

^58 , 074011 (1998).

The Observables: 0

-^ mesons

„^ Photoproduction described by 4complex amplitudes „^ Bilinear combinations define 16observables „^ 8 measurements

*^ needed to separate amplitudes at any given energy, W^ „^ differential cross section: d

σ/dΩ

„^ 3 single polarization observables: P, T,

Σ

„^ 4 double polarization

observables… * W-T. Chiang and F. Tabakin Phys Rev. C 55 2054 (1997)

May-31-2010, MENU^

R. A. Schumacher, Carnegie Mellon University

May-31-2010, MENU^

R. A. Schumacher, Carnegie Mellon University

16 Pseudoscalar MesonPhotoproduction Observables

I. S. Barker, A.I. S. Barker, A. Donnachie

Donnachie, J. K., J. K. Storrow

Storrow,, NuclNucl. Phys. B95 347 (1975).. Phys. B95 347 (1975). Single Polarization^ Single PolarizationBeam & TargetBeam & TargetBeam & RecoilBeam & RecoilTarget & RecoilTarget & Recoil

{^ { {{ {{ {{

For^ γ^ + pÆ

+^ , K Λ:

R. Bradfordet al. PRC C. Patersonet al. (Glasgow),to be published C. Patersonet al. (Glasgow),to be published

^73 035202 (2006), M. McCracken et al,PRC^^81 , 025201 (2010).J. McNabbet al. PRC

^69^042201 (2004), M. McCracken et al, PR C

^81 , 025201 (2010). R. Bradfordet al. Phys. Rev. C

^75 FroST (g9a) under analysis FroST (g9b) data in 2010 035205 (2007) FroST (g9b) data in 2010FroST (g9a) under analysis

May-31-2010, MENU^

R. A. Schumacher, Carnegie Mellon University

8

γpÆK

+Λ^ Cross Sections

„^ Two-bumpstructure seen „^ Resonance-likestructure at1.9 GeV:^ „^ D^13

(Bennhold & Mart)

a „^ P(Bonn-Gachina)^13

b „^ P(Ghent “RPR” model)^11

c „^ KKN bound state(Valencia model)

d „^ Coupled-channeleffects

e (Giessen)

R. Bradfordet al. Phys. Rev. C

73 035202 (2006) K. H. Glander

et al. Eur. Phys. J. A

19 251 (2004) Energy, W (GeV)

a) T, Mart, C. Bennhold, Phys Rev C

^61 , 012201(R) (1999). b) V. Nikanov et al, Phys Lett B

^662 , 245 (2008). c) T. Corthals, et al., PRC

^73 , 045207 (2006). d) A. MartinezTorres, et al.,

Eur. Phys J. A 41,

^361 (2009). e) R. Shyam, O.Scholten & H.Lenske, PRC

^81 , 015204 (2010).

γpÆK

+Λ^ Cross Sections

May-31-2010, MENU^

R. A. Schumacher, Carnegie Mellon University

„^ Kaon-MAID model(green)^ „^ F.X.Lee et al., Nucl.Phys.

A695 , 237 (2001). „ Single-channel BWresonance fits „ No longer up-to-date

„^ Bonn-Gachina model(blue)^ „^ A.V. Sarantsev et al.,Eur. Phys. J., A

^25 , 441

(2005). „ Multi-channel, unitary,BW resonance fit „ Large suite of N*contributions „ Was not predictive forrecoil polarization M. McCracken et al, (CLAS) Phys. Rev. C

^81 , 025201 (2010).

γpÆK

+^0 ΣCross Sections

May-31-2010, MENU^

R. A. Schumacher, Carnegie Mellon University

„^ New results from CLAS „^ Unbinned maximumlikelihood method „^ Excellent agreementwith previous CLASpublication

(Bradford etal.)

„^ Resonance-likestructure at 2.3 GeV atback angles „^ PWA analysis underway B. Deyet al. (CLAS) to be submitted (2010)

γnÆK

−^ +Σon bound neutrons

„^ First “complete”look at Yproduction offneutron „^ Deuterontarget, protonspectator, FSI~ 10% „^ Modeled with K

and K*(892) inRegge tra-jectories (noresonances)^ „^ Ghent model,Ryckebuschet al. „ Hint of back-angle rise

Æ^ u- channelcontribution

Related talk: P. Vancraeyveld: Session 2E May-31-2010, MENU^

R. A. Schumacher, Carnegie Mellon University S. Anefalos Pereira

et al., (CLAS) PhysLett B

^688 , 289 (2010)

Define the Spin Observables

(for target polarization zero)

1 cos 2cos 0 sin 2^

cos cos^ sin 2

cos cos^

x^ cos cos 2

x z x^

x z^

z y^

y

z O^

C

O^

C

P

P^

P

d

P^

P T

d

P

γ^ γ γ P

γ

φ α θ φ^

α^ θ

σ^ σ^

α^ θ^

φ^ α^

α^ θ^

α^ θ

′^

′′ ′ ′ ′^

′ ′^

′

′

−⎧

⎪^

−^

⎪^

=^ ⎨^

−^

Ω^ ⎪^

⎪^

+^

G

G^

: G^

: G

proton ˆ x ˆ y ˆ z

ˆ′ z ˆ′ x ′ ˆ y

G γ G Λ ˆ z − π (^) ˆ x ˆ y

Θ^ p

.^. c m Θ+ K

proton

K+

G P γ P : May-31-2010, MENU^

R. A. Schumacher, Carnegie Mellon University

14

Polarization comparison May-31-2010, MENU^

R. A. Schumacher, Carnegie Mellon University „^ Naïve SU(6) expectation: „^ True in forward direction „^ False in backward direction

B. Deyet al. (CLAS) to be submitted (2010)

0 P^

P Λ^ −Σ

(^0) Σ Λ

Beam Asymmetry

1 cos 2cos 0 sin 2^

cos cos^ sin 2

cos cos^

x^ cos cos 2

x z x^

x z^

z y^

y

z O^

C

O^

C

P

P^

P

d

P^

P T

d

P

γ^ γ γ P

γ

φ α θ φ^

α^ θ

σ^ σ^

α^ θ^

φ^ α^

α^ θ^

α^ θ

′^

′′ ′ ′ ′^

′ ′^

′

′

−⎧

⎪^

−^

⎪^

=^ ⎨^

−^

Ω^ ⎪^

⎪^

+^

G

G^

: G^

: G Azimuthal angle w.r.t.beam polarization

G γ

proton ˆ x ˆ y ˆ z

′ ˆ z ˆ′ x ˆ′ y

G Λ ˆ z − π (^) ˆ x ˆ y

Θ^ p

.^. c m Θ+ K^

proton

K+

G P γ May-31-2010, MENU^

R. A. Schumacher, Carnegie Mellon University

17

Polarization Transfer for Linear Beam Polarization

1 cos 2cos 0 sin 2^

cos cos^ sin 2

cos cos^

x^ cos cos 2

x z x^

x z^

z y^

y

z O^

C

O^

C

P

P^

P

d

P^

P T

d

P

γ^ γ γ P

γ

φ α θ φ^

α^ θ

σ^ σ^

α^ θ^

φ^ α^

α^ θ^

α^ θ

′^

′′ ′ ′ ′^

′ ′^

′

′

−⎧

⎪^

−^

⎪^

=^ ⎨^

−^

Ω^ ⎪^

⎪^

+^

G

G^

: G^

: G

G γ

proton ˆ x ˆ y ˆ z

′ ˆ z ˆ′ x ˆ′ y

G Λ ˆ z − π (^) ˆ x ˆ y

Θ^ p

.^. c m Θ+ K^

proton

K+

G P γ May-31-2010, MENU^

R. A. Schumacher, Carnegie Mellon University

19

May-31-2010, MENU^

R. A. Schumacher, Carnegie Mellon University

γpÆK

+Λ^ Beam-Recoil O

and Ox

z

Craig Paterson (Glasgow)

KaonMAID;^

RPR2-Regge only;

RPR2-core;

RPR2-w/D

+1 0 -1^ cos

θ +1 0 -

OPreliminaryx^ cos^ θ

OPreliminaryz^ cos^ θ