Pion-Nucleon Charge Exchange in the N*(1440) Resonance Region

Michael Sadler, Melissa JerkinsMichael Sadler, Melissa Jerkins

and Shon Watsonand Shon Watson

Abilene Christian UniversityAbilene Christian University

For the Crystal Ball CollaborationFor the Crystal Ball Collaboration

Crystal Ball Collaboration at BNLCrystal Ball Collaboration at BNLA. Barker (deceased), C. Bircher, C. Carter, M. Daugherity, B. Draper, S. Hayden, J. Huddleston, D. Isenhower, M. Jerkins, M. Joy, C. Robinson, M. Sadler and S. Watson, Abilene Christian University, C. Allgower, R. Cadman and H. Spinka, Argonne National Laboratory, J. Comfort, K. Craig* and A. Ramirez*, Arizona State University, T. Kycia (deceased), Brookhaven National Laboratory, M. Clajus, A. Marusic, S. McDonald, B. M. K. Nefkens, N. Phaisangittisakul*, S. Prakhov, J. Price, A. Starostin* and W. B. Tippens, University of California at Los Angeles, J. Peterson, University of Colorado, W. Briscoe, A. Shafi* and I. Strakovsky, George Washington University, H. Staudenmaier, Universität Karlsruhe, D. M. Manley and J. Olmsted*, Kent State University, D. Peaslee, University of Maryland, V. Abaev, V. Bekrenev, N. Kozlenko*, S. Kruglov, A. Kulbardis, and I. Lopatin, Petersburg Nuclear Physics Institute, N. Knecht*, G. Lolos and Z. Papandreou, University of Regina, I. Supek and D. Mekterovic*, Rudjer Boskovic Institute, and D. Grosnick, D. D. Koetke, R. Manweiler and S. Stanislaus, Valparaiso University

Experiment Spokespersons* Ph.D. Students (total of 9)

Crystal BallCrystal Ballmultiphoton multiphoton spectrometerspectrometer

672 NaI crystals.Individual PMT’s

~93% of 4π sr

V. Bekrenev mounting PM tubesV. Bekrenev mounting PM tubes

The Crystal BallThe Crystal Ball

The Crystal BallThe Crystal Ball

Crystal Ball Crystal Ball layout in the C6 layout in the C6 beam line at the beam line at the

Brookhaven Brookhaven AGSAGS

Crystal Ball layout in the Crystal Ball layout in the C6 beam line at the C6 beam line at the Brookhaven AGSBrookhaven AGS

Invariant Mass for neutral meson decay, e.g. πInvariant Mass for neutral meson decay, e.g. π00 to 2 to 2

E 2 (pc)2 (mc 2 )2 , or E 2 p2 m 2 in units where c1.

m E 2 p2 ,where E E1E

2, and pp

1 p

2

(E1E

2)2 (p

1 p

2)2 E

1

2 2E1E

2E

2

2 (p1

2 2p1 p

2 p

2

2 )

2E1E

2(1 cos)

π0 rest frame

180°

0

lab frame

E1p

1c

E2p

2c

0

0

Identification of Neutral Mesons from their Invariant MassIdentification of Neutral Mesons from their Invariant Mass

πo

p Neutrals

P 720MeV /c

Non-strange Spectroscopy:π- p π°nπ- p π°π°nπ- p π°π°π°nπ- p nπ- p nπ- p π°nNeutron detection

Nuclear Physics:π- A π°Xπ- A π°π°Xπ- A X

Eta decays:π°π°π°π°π°π°π°π°π°π°π°π°π°π°π°

Antiprotons: neutrals (π°,

K -p K 0n

K -p 0

K -p 00

K -p 000

K -p 0

K -p 00

K -p 000

K -p

K -p

K -p

p p

Strange Spectroscopy:

Quantity of data:20 momenta for π-p 2 “ π-A 1 “ 8 “ K-p ~3•107 ’s

Crystal Ball DataCrystal Ball Data

153 MeV/c153 MeV/c

172 MeV/c172 MeV/c

185 MeV/c185 MeV/c

200 MeV/c200 MeV/c

218 MeV/c218 MeV/c

247 MeV/c247 MeV/c

267 MeV/c267 MeV/c

301 MeV/c301 MeV/c

320 MeV/c320 MeV/c

351 MeV/c351 MeV/c

378 MeV/c378 MeV/c

408 MeV/c408 MeV/c

456 MeV/c456 MeV/c

490 MeV/c490 MeV/c

532 MeV/c532 MeV/c

614 MeV/c614 MeV/c

658 MeV/c658 MeV/c

π-p π0n Overview

π-p π0n excitation functions

π-p π0n excitation functions

π-p π0n excitation functions

π-p π0n excitation functions

π-p π0n excitation functions

π-p π0n excitation functions

Call for a new determination of the P11(1440) resonance parameters

Aliases for the lowest lying state with Aliases for the lowest lying state with I = 1/2, JI = 1/2, JP P = 1/2= 1/2++

N*(1440)N*(1440) PP1111(1440)(1440)

Roper resonanceRoper resonance First excited state of the nucleonFirst excited state of the nucleon

What do we learn from PWA?What do we learn from PWA?

Input forN term. Charge symmetry breaking. Resonance parameters (P11, S11, D13) – masses,

widths, decay modes. Interface between experiment and models.

Quark modelsSkyrme modelsCollective models

N(1440) summary in Review of Particle PhysicsN(1440) summary in Review of Particle Physics

N(1440) summary in Review of Particle PhysicsN(1440) summary in Review of Particle Physics

N(1440) summary in Review of Particle PhysicsN(1440) summary in Review of Particle Physics

Arndt, et al., Phys. Rev. C69, 035213 (2004).Arndt, et al., Phys. Rev. C69, 035213 (2004).

Arndt, et al., Phys. Rev. C69, 035213 (2004).Arndt, et al., Phys. Rev. C69, 035213 (2004).

Summary of Pion-Nucleon Reactions and Observables

Reactions Observablesπ+p π+p d/dπ-p π-p P (=AN)π-p πon A and R

π-p nπ-p πoπonπ-p n

πN Experiments at LAMPF and BNLDate Experiment Measurement

1978 LAMPF Exp. 363

d

d for š ±p š

±p (378-687 MeV/c)

1979-80 LAMPF Exp. 120

d

d for š-p šon (300-687 MeV/c)

1982 LAMPF Exp. 120* AN for š±p š

±p (471-687 MeV/c)

1983 LAMPF Exp. 120** AN for š-p šon (471-687 MeV/c)

1984 LAMPF Exp. 804 AN for š-p n and š-p šon (300-625 MeV/c)

1984 LAMPF Exp. 808

d

d for š-p šon near 0° (100-150 MeV/c)

1985 LAMPF Exp. 882

d

d for š-p šon (55, 78 and 112 MeV/c)

1985 LAMPF Exp. 807 P for š±p š

±p (547-625 MeV/c)

1986 LAMPF Exp. 806 A and R (spin rotation parameters)for š

±p š

±p (427, 471, 547 and 625 MeV/c)

1988 LAMPF Exp. 849

d

d for š-p šon near 0Þ and 180Þ (427-687 MeV/c)

1992-93 LAMPF Exp. 1268

d

d for š-p šon near the (240-378 MeV/c)

1995 LAMPF Exp. 1178 AN for š-p šon at 192-326 MeV/c

1995 BNL Exp. 909

d

d for š-p n at 685-750 MeV/c

1997-98 BNL Exp. 913/914

d

d for š-p and K-p Neutrals (150-750 MeV/c)

2002 BNL Exp. 958

d

d for š-p šon at 112-186 MeV/c

625 MeV/c π+p

p p625 MeV/c

625 MeV/c π-p

p p625 MeV/c

625 MeV/c π-p π0n

ππ- - p Total Cross Sectionp Total Cross Section

1440

1440

PP1111 (1440) speed plot from multichannel analysis (1440) speed plot from multichannel analysis

From D. M. Manley, Proc. of the Workshop on the Physics of Excited Nucleons (NSTAR 2004), World Scientific.

Speed = |dT/dW|, whereT = elastic T-matrix amplitude.

ππ--p p π π0 0 ππ00nntottot

1440

ππ--ppππ0 0 ππ00nnDalitz plotsDalitz plots

Crystal BallPrakhov, et al.PRC 69,045202 (2004)

Summary of Present Status

Listings in Review of Particle Properties rely on PWA’s from 1980.

GWU (formerly VPI) analyses fit data well, but not included in averages.

Analyses should include πp->ππN. PWA for hadronic channels is needed to analyze data

from photo- and electro-production of resonances. No present experimental facilities for baryon

spectroscopy (1-3 GeV/c π’s, K’s).

Beginnings of a new PWA effort, Abilene 2004Beginnings of a new PWA effort, Abilene 2004

Beginnings of a new PWA effort, Zagreb 2005Beginnings of a new PWA effort, Zagreb 2005

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

ConclusionsConclusions

New PWA efforts are needed to determine properties New PWA efforts are needed to determine properties of the Pof the P1111(1440) resonance.(1440) resonance.

Complete data sets now available.Complete data sets now available. KH and CMB analyses completed in 1980.KH and CMB analyses completed in 1980. New PWA’s can be extended to higher resonances New PWA’s can be extended to higher resonances

when data become available from new facilities.when data become available from new facilities. MIPP at FNAL presents a new possibility (if eventually MIPP at FNAL presents a new possibility (if eventually

approved) to make measurements in the πN resonance approved) to make measurements in the πN resonance region (1-3 GeV/c) and with kaon beams higher than 3 region (1-3 GeV/c) and with kaon beams higher than 3 GeV/c.GeV/c.

J-PARC (near Tokyo) is a future hadron facility. Call for new J-PARC (near Tokyo) is a future hadron facility. Call for new proposals is expected this year. proposals is expected this year.

An intermediate experiment on non-strange resonances near An intermediate experiment on non-strange resonances near 1710 MeV is planned at ITEP (Moscow).1710 MeV is planned at ITEP (Moscow).