Friday Afternoon Journal Club: “Vector-Meson Production by Polarized Photons at 2.8, 4.7, and 9.3...

1

Friday Afternoon Journal Club

ldquoVector-Meson Production by Polarized Photons at 28 47 and 93 GeVrdquo PRD 7 3150 (1973)

D Mack (TJNAF)61215

2

some context

3

The SLAC Polarized Gamma Facility

bullA polarized photon beam for the SLAC 82-inch hydrogen bubble chamber CK Sinclair (Tufts U) JJ Murray PR Klein (Stanford U Phys Dept) M Rabin (UC Berkeley) 1969 Published in IEEE TransNuclSci 16 (1969) 1065-1068 DOI 101109TNS19694325441 Presented at Conference C69-03-05 Proceedings References | BibTeX | LaTeX(US) | LaTeX(EU) | Harvmac | EndNote bullFull-text at JACoW Server

E Ruby Laser

E Primary e-

E Backscatt

Gamma

Polarization

178 eV 12 GeV 28 GeV 93

178 eV 16 GeV 47 Gev 91

2x178 eV 19 GeV 93 GeV 77

bull Mono-energetic (if broad) gamma beam with high linear polarization

bull 93 GeV was their technical limit they had to use a frequency doubling xtal and push the accelerator energy

bull 82rdquo LH2 bubble chamber detection (hence no photons observed π0 by Mx only)

10 μrad collimation

4

Where This Talk (Sort of) Fits InDateLead

Paper

Supple-mental Paper

ρ(770) ω(782) φ(1020) Excited ρrsquos

Etc

52915Shepherd

PRL 53 751 (1984)

PRL 103 231801 (2009)

π+π-

5


Paper

Supple-mental Paper


Etc

52915Shepherd

PRL 53 751 (1984)

PRL 103 231801 (2009)

π+π-

ZPC 33 407-417 (1987)

4π

6


Paper

Supple-mental Paper


Etc

52915Shepherd

PRL 53 751 (1984)

PRL 103 231801 (2009)

π+π-

61215Mack

PRD 7 3150 (1973)

π+π-

π+π-π0 K+K-

ZPC 33 407-417 (1987)

4π

Other than for didactic purposes I thought this paper (thanks Justin) might suggest

early contributions GlueX could make near 93 GeV

eg the ndasht dependence of the asymmetry

7

Forward Light Meson Photoproduction Xsects at 93 GeV

π+π- (rho) π+π-π0 (omega)

k+k- (phi) ppbar eta0

5

10

15

Cros

s Sec

tion

(micr

obar

ns)

ρ ω φ p-pbar η

Values from compilation byAR Dzierba

GlueX-doc-835-v1

These are big signals

up to 10 of the ~125 μbarn total hadronic xsect at

this energy

But is there low-hanging fruit for an early GlueX

publication

8

on to the paper

9

ρ γ + p p + π+π-

Fig 3a

10

ρrsquo misc

This 1973 work didnrsquot have much sensitivity

The 1984 paper Matt covered last time had higher statistics around M2π ~ 15 and suggested something was going on (I wonder if they made a plot like that on the right)

The 1987 suggested paper by Ryan found two resonances with the best signatures in 4π

11

ω γ + p p + π+π- (π0)π0

ω

ηGlueX

η

ω

φ ρΔ etc

Statistics on xsect and asymmetry look scruffy near 93 GeV Is this M Staibrsquos thesis

12

ωrsquo misc

Focus on highest beam energy a la GlueX

bull the lower ndashtmin makes production by t-channel exchange more efficient

bull plus better separation of current and target fragments (next slide)

13

Overlap of Current and Target Fragments in γ + p p + π+π-π0

AR Dzierba GlueX-doc-838-v4

There are similar backgrounds for bull ρ photoproduction γ+pΔ++π- pπ+ π- and possibly bull φ photoproduction γ+pΛ(1520)K+ pK- K+ (see Fig 4 of Anciant et al paper)Looks small for η photoproduction but it might be important in a precision η3π Dalitz distribution like we hope to measure

14

ldquoPhirdquo γ + p p + K+K-

High statistics φ xsects

exist (from a different

expt)

Statistics was very

thin on the

asymmetry

Presumably therersquos been no change near 93

GeV

If this is low-

hanging fruit

whatrsquos the physics

15

CLAS Paper from 2000

E Anciant et al PhysRevLett854682-46862000

Phi photoproduction at large ndasht is supposed to be easier to model than rho or omega due to suppression of quark exchange with the target

CLAS saw interesting deviations in the xsect above ~ 2 GeV2 suggesting 2-gluon exchange (See also K McCormick et al httpjournalsapsorgprcabstract101103PhysRevC69032203 which used the same 2-gluon exchange model)

Itrsquos conceivable the asymmetry might show interesting evolution as low as ndasht ~ 1 GeV2

16

Xsect ~ b12 + b2

2 + b32 + b4

2

Σ ~ b12 + b2

2 - b32 - b4

2

PERHAPS the asymmetry for φ

photoproduction would make a stronger case

for the two-gluon exchange

Reinhardrsquos slide from the Userrsquos Group meeting

17

end

18

Exclusive γ + p p + π+π-π0

Data figures by J Stevens

Completed calibrations should result in a well-isolated η peak

(above)

Simulations

ω π+π- π0 combines charged particle and photon reconstruction (xsect still large but 10x smaller than ρ)

Calibrations now good enough to see a hint of η3π

ω

η

Data

ω

φ

η

Friday Afternoon Journal Club ldquoVector-Meson Production by Pol

some context


Where This Talk (Sort of) Fits In

Where This Talk (Sort of) Fits In (2)



on to the paper

ρ γ + p p + π+π-

ρrsquo misc

ω γ + p p + π+π- (π0)

ωrsquo misc




Slide 16

end


2

some context

3



E Ruby Laser

E Primary e-

E Backscatt

Gamma

Polarization

178 eV 12 GeV 28 GeV 93

178 eV 16 GeV 47 Gev 91

2x178 eV 19 GeV 93 GeV 77





4


Paper

Supple-mental Paper


Etc

52915Shepherd

PRL 53 751 (1984)

PRL 103 231801 (2009)

π+π-

5


Paper

Supple-mental Paper


Etc

52915Shepherd

PRL 53 751 (1984)

PRL 103 231801 (2009)

π+π-

ZPC 33 407-417 (1987)

4π

6


Paper

Supple-mental Paper


Etc

52915Shepherd

PRL 53 751 (1984)

PRL 103 231801 (2009)

π+π-

61215Mack

PRD 7 3150 (1973)

π+π-

π+π-π0 K+K-

ZPC 33 407-417 (1987)

4π




7




5

10

15

Cros

s Sec

tion

(micr

obar

ns)

ρ ω φ p-pbar η


GlueX-doc-835-v1



this energy


publication

8

on to the paper

9

ρ γ + p p + π+π-

Fig 3a

10

ρrsquo misc




11

ω γ + p p + π+π- (π0)π0

ω

ηGlueX

η

ω

φ ρΔ etc


12

ωrsquo misc




13




14




expt)

Statistics was very

thin on the

asymmetry


GeV

If this is low-

hanging fruit


15






16

Xsect ~ b12 + b2

2 + b32 + b4

2

Σ ~ b12 + b2

2 - b32 - b4

2





17

end

18




(above)

Simulations



ω

η

Data

ω

φ

η


some context






on to the paper

ρ γ + p p + π+π-

ρrsquo misc

ω γ + p p + π+π- (π0)

ωrsquo misc




Slide 16

end


3



E Ruby Laser

E Primary e-

E Backscatt

Gamma

Polarization

178 eV 12 GeV 28 GeV 93

178 eV 16 GeV 47 Gev 91

2x178 eV 19 GeV 93 GeV 77





4


Paper

Supple-mental Paper


Etc

52915Shepherd

PRL 53 751 (1984)

PRL 103 231801 (2009)

π+π-

5


Paper

Supple-mental Paper


Etc

52915Shepherd

PRL 53 751 (1984)

PRL 103 231801 (2009)

π+π-

ZPC 33 407-417 (1987)

4π

6


Paper

Supple-mental Paper


Etc

52915Shepherd

PRL 53 751 (1984)

PRL 103 231801 (2009)

π+π-

61215Mack

PRD 7 3150 (1973)

π+π-

π+π-π0 K+K-

ZPC 33 407-417 (1987)

4π




7




5

10

15

Cros

s Sec

tion

(micr

obar

ns)

ρ ω φ p-pbar η


GlueX-doc-835-v1



this energy


publication

8

on to the paper

9

ρ γ + p p + π+π-

Fig 3a

10

ρrsquo misc




11

ω γ + p p + π+π- (π0)π0

ω

ηGlueX

η

ω

φ ρΔ etc


12

ωrsquo misc




13




14




expt)

Statistics was very

thin on the

asymmetry


GeV

If this is low-

hanging fruit


15






16

Xsect ~ b12 + b2

2 + b32 + b4

2

Σ ~ b12 + b2

2 - b32 - b4

2





17

end

18




(above)

Simulations



ω

η

Data

ω

φ

η


some context






on to the paper

ρ γ + p p + π+π-

ρrsquo misc

ω γ + p p + π+π- (π0)

ωrsquo misc




Slide 16

end


4


Paper

Supple-mental Paper


Etc

52915Shepherd

PRL 53 751 (1984)

PRL 103 231801 (2009)

π+π-

5


Paper

Supple-mental Paper


Etc

52915Shepherd

PRL 53 751 (1984)

PRL 103 231801 (2009)

π+π-

ZPC 33 407-417 (1987)

4π

6


Paper

Supple-mental Paper


Etc

52915Shepherd

PRL 53 751 (1984)

PRL 103 231801 (2009)

π+π-

61215Mack

PRD 7 3150 (1973)

π+π-

π+π-π0 K+K-

ZPC 33 407-417 (1987)

4π




7




5

10

15

Cros

s Sec

tion

(micr

obar

ns)

ρ ω φ p-pbar η


GlueX-doc-835-v1



this energy


publication

8

on to the paper

9

ρ γ + p p + π+π-

Fig 3a

10

ρrsquo misc




11

ω γ + p p + π+π- (π0)π0

ω

ηGlueX

η

ω

φ ρΔ etc


12

ωrsquo misc




13




14




expt)

Statistics was very

thin on the

asymmetry


GeV

If this is low-

hanging fruit


15






16

Xsect ~ b12 + b2

2 + b32 + b4

2

Σ ~ b12 + b2

2 - b32 - b4

2





17

end

18




(above)

Simulations



ω

η

Data

ω

φ

η


some context






on to the paper

ρ γ + p p + π+π-

ρrsquo misc

ω γ + p p + π+π- (π0)

ωrsquo misc




Slide 16

end


5


Paper

Supple-mental Paper


Etc

52915Shepherd

PRL 53 751 (1984)

PRL 103 231801 (2009)

π+π-

ZPC 33 407-417 (1987)

4π

6


Paper

Supple-mental Paper


Etc

52915Shepherd

PRL 53 751 (1984)

PRL 103 231801 (2009)

π+π-

61215Mack

PRD 7 3150 (1973)

π+π-

π+π-π0 K+K-

ZPC 33 407-417 (1987)

4π




7




5

10

15

Cros

s Sec

tion

(micr

obar

ns)

ρ ω φ p-pbar η


GlueX-doc-835-v1



this energy


publication

8

on to the paper

9

ρ γ + p p + π+π-

Fig 3a

10

ρrsquo misc




11

ω γ + p p + π+π- (π0)π0

ω

ηGlueX

η

ω

φ ρΔ etc


12

ωrsquo misc




13




14




expt)

Statistics was very

thin on the

asymmetry


GeV

If this is low-

hanging fruit


15






16

Xsect ~ b12 + b2

2 + b32 + b4

2

Σ ~ b12 + b2

2 - b32 - b4

2





17

end

18




(above)

Simulations



ω

η

Data

ω

φ

η


some context






on to the paper

ρ γ + p p + π+π-

ρrsquo misc

ω γ + p p + π+π- (π0)

ωrsquo misc




Slide 16

end


6


Paper

Supple-mental Paper


Etc

52915Shepherd

PRL 53 751 (1984)

PRL 103 231801 (2009)

π+π-

61215Mack

PRD 7 3150 (1973)

π+π-

π+π-π0 K+K-

ZPC 33 407-417 (1987)

4π




7




5

10

15

Cros

s Sec

tion

(micr

obar

ns)

ρ ω φ p-pbar η


GlueX-doc-835-v1



this energy


publication

8

on to the paper

9

ρ γ + p p + π+π-

Fig 3a

10

ρrsquo misc




11

ω γ + p p + π+π- (π0)π0

ω

ηGlueX

η

ω

φ ρΔ etc


12

ωrsquo misc




13




14




expt)

Statistics was very

thin on the

asymmetry


GeV

If this is low-

hanging fruit


15






16

Xsect ~ b12 + b2

2 + b32 + b4

2

Σ ~ b12 + b2

2 - b32 - b4

2





17

end

18




(above)

Simulations



ω

η

Data

ω

φ

η


some context






on to the paper

ρ γ + p p + π+π-

ρrsquo misc

ω γ + p p + π+π- (π0)

ωrsquo misc




Slide 16

end


7




5

10

15

Cros

s Sec

tion

(micr

obar

ns)

ρ ω φ p-pbar η


GlueX-doc-835-v1



this energy


publication

8

on to the paper

9

ρ γ + p p + π+π-

Fig 3a

10

ρrsquo misc




11

ω γ + p p + π+π- (π0)π0

ω

ηGlueX

η

ω

φ ρΔ etc


12

ωrsquo misc




13




14




expt)

Statistics was very

thin on the

asymmetry


GeV

If this is low-

hanging fruit


15






16

Xsect ~ b12 + b2

2 + b32 + b4

2

Σ ~ b12 + b2

2 - b32 - b4

2





17

end

18




(above)

Simulations



ω

η

Data

ω

φ

η


some context






on to the paper

ρ γ + p p + π+π-

ρrsquo misc

ω γ + p p + π+π- (π0)

ωrsquo misc




Slide 16

end


8

on to the paper

9

ρ γ + p p + π+π-

Fig 3a

10

ρrsquo misc




11

ω γ + p p + π+π- (π0)π0

ω

ηGlueX

η

ω

φ ρΔ etc


12

ωrsquo misc




13




14




expt)

Statistics was very

thin on the

asymmetry


GeV

If this is low-

hanging fruit


15






16

Xsect ~ b12 + b2

2 + b32 + b4

2

Σ ~ b12 + b2

2 - b32 - b4

2





17

end

18




(above)

Simulations



ω

η

Data

ω

φ

η


some context






on to the paper

ρ γ + p p + π+π-

ρrsquo misc

ω γ + p p + π+π- (π0)

ωrsquo misc




Slide 16

end


9

ρ γ + p p + π+π-

Fig 3a

10

ρrsquo misc




11

ω γ + p p + π+π- (π0)π0

ω

ηGlueX

η

ω

φ ρΔ etc


12

ωrsquo misc




13




14




expt)

Statistics was very

thin on the

asymmetry


GeV

If this is low-

hanging fruit


15






16

Xsect ~ b12 + b2

2 + b32 + b4

2

Σ ~ b12 + b2

2 - b32 - b4

2





17

end

18




(above)

Simulations



ω

η

Data

ω

φ

η


some context






on to the paper

ρ γ + p p + π+π-

ρrsquo misc

ω γ + p p + π+π- (π0)

ωrsquo misc




Slide 16

end


10

ρrsquo misc




11

ω γ + p p + π+π- (π0)π0

ω

ηGlueX

η

ω

φ ρΔ etc


12

ωrsquo misc




13




14




expt)

Statistics was very

thin on the

asymmetry


GeV

If this is low-

hanging fruit


15






16

Xsect ~ b12 + b2

2 + b32 + b4

2

Σ ~ b12 + b2

2 - b32 - b4

2





17

end

18




(above)

Simulations



ω

η

Data

ω

φ

η


some context






on to the paper

ρ γ + p p + π+π-

ρrsquo misc

ω γ + p p + π+π- (π0)

ωrsquo misc




Slide 16

end


11

ω γ + p p + π+π- (π0)π0

ω

ηGlueX

η

ω

φ ρΔ etc


12

ωrsquo misc




13




14




expt)

Statistics was very

thin on the

asymmetry


GeV

If this is low-

hanging fruit


15






16

Xsect ~ b12 + b2

2 + b32 + b4

2

Σ ~ b12 + b2

2 - b32 - b4

2





17

end

18




(above)

Simulations



ω

η

Data

ω

φ

η


some context






on to the paper

ρ γ + p p + π+π-

ρrsquo misc

ω γ + p p + π+π- (π0)

ωrsquo misc




Slide 16

end


12

ωrsquo misc




13




14




expt)

Statistics was very

thin on the

asymmetry


GeV

If this is low-

hanging fruit


15






16

Xsect ~ b12 + b2

2 + b32 + b4

2

Σ ~ b12 + b2

2 - b32 - b4

2





17

end

18




(above)

Simulations



ω

η

Data

ω

φ

η


some context






on to the paper

ρ γ + p p + π+π-

ρrsquo misc

ω γ + p p + π+π- (π0)

ωrsquo misc




Slide 16

end


13




14




expt)

Statistics was very

thin on the

asymmetry


GeV

If this is low-

hanging fruit


15






16

Xsect ~ b12 + b2

2 + b32 + b4

2

Σ ~ b12 + b2

2 - b32 - b4

2





17

end

18




(above)

Simulations



ω

η

Data

ω

φ

η


some context






on to the paper

ρ γ + p p + π+π-

ρrsquo misc

ω γ + p p + π+π- (π0)

ωrsquo misc




Slide 16

end


14




expt)

Statistics was very

thin on the

asymmetry


GeV

If this is low-

hanging fruit


15






16

Xsect ~ b12 + b2

2 + b32 + b4

2

Σ ~ b12 + b2

2 - b32 - b4

2





17

end

18




(above)

Simulations



ω

η

Data

ω

φ

η


some context






on to the paper

ρ γ + p p + π+π-

ρrsquo misc

ω γ + p p + π+π- (π0)

ωrsquo misc




Slide 16

end


15






16

Xsect ~ b12 + b2

2 + b32 + b4

2

Σ ~ b12 + b2

2 - b32 - b4

2





17

end

18




(above)

Simulations



ω

η

Data

ω

φ

η


some context






on to the paper

ρ γ + p p + π+π-

ρrsquo misc

ω γ + p p + π+π- (π0)

ωrsquo misc




Slide 16

end


16

Xsect ~ b12 + b2

2 + b32 + b4

2

Σ ~ b12 + b2

2 - b32 - b4

2





17

end

18




(above)

Simulations



ω

η

Data

ω

φ

η


some context






on to the paper

ρ γ + p p + π+π-

ρrsquo misc

ω γ + p p + π+π- (π0)

ωrsquo misc




Slide 16

end


17

end

18




(above)

Simulations



ω

η

Data

ω

φ

η


some context






on to the paper

ρ γ + p p + π+π-

ρrsquo misc

ω γ + p p + π+π- (π0)

ωrsquo misc




Slide 16

end


18




(above)

Simulations



ω

η

Data

ω

φ

η


some context






on to the paper

ρ γ + p p + π+π-

ρrsquo misc

ω γ + p p + π+π- (π0)

ωrsquo misc




Slide 16

end


Friday Afternoon Journal Club: “Vector-Meson Production by Polarized Photons at 2.8, 4.7, and 9.3...

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Transcript of Friday Afternoon Journal Club: “Vector-Meson Production by Polarized Photons at 2.8, 4.7, and 9.3...