Meson Spectroscopy at CLAS

Thomas Jefferson National Accelerator Facility

D.P. WeygandCLAS Collaboration

GLUE88/BNL

I have been using the constituent quark model for many years now as a tool for understanding the spectrum and properties of the low-lying mesons and baryons. For most of this time I have been painfully aware of the difficulty of understanding from first principles (i.e., from QCD) why such a model should work. I have nevertheless had faith that we would eventually be able to justify the use of this model simply because it is such a good representation of the physics.

At the same time, the picture I will propose to rationalize the success of the quark model (which is related to the old string model) leads inevitably to a model for states beyond the quark model: hybrids, glueballs, and multiquark states.

Nathan Isgur, b. 1947, d. 2001

photoproduction

Partial Wave Analysis

isobar

Likelihood function:

CLAS g12 run

CLAS g12 runEe = 5.715 GeVI = 65 nAEg = 3.58-5.45 GeV26.2 X 109 triggersL = 68 pb-1

Raw ppp mass spectra

C. Bookwalter thesis

Baryon background

COMPASS

a1(1260)/a2(1320)/p2(1670)

p1(1600) phase

E852/1998

p0 sidebands

GeV/c2

ppp masssideband subtracted ppp mass

GeV/c2

E852 1997

D. Schott Thesis

a2(1320) Breit-Wigner

mass = 1.32± 0.01 GeV

= 0.14G ± 0.01 GeV

M. Saini Thesis

Strangeonium

JPC Mass (MeV)

1-- 102318191862

2-- 19793-- 21231+- 1489

LQCD: Hadron Spectrum Collaboration

Xeon Phi

PWA fitting program currently being developed on Xeon Phi MIC

Summary

• CLAS-g12: High luminosity, high energy data set (5.5 GeV/c, 68 pb-1)

• ~106 exclusive g p n p+p+p- events• PWA from 1 to 2 GeV• Clear signals for a1(1260), a2(1320) and p2(1670) • No evidence for p1(1600) exotic (neither intensity nor phase)

• Consistent with previous CLAS result• Consistent with Pomeron exchange

• Search for exotic p1(1400) in - ( hp p exchange)• Clear signal for a2(1320)• No evidence for p1(1400)

• Strangeonium ( f h)• No significant resonant structures

• Prospects• Neutral p+p-p0

• KsKs

• K+K-

Collaborative (Jlab,GWU) Effort to Include Baryon Resonances in PWA

Meson Spectroscopy at CLAS

Documents

Meson spectroscopy - glueballs

Charmed Meson Spectroscopy Robert K. Kutschke Fermilab HQL04 June 4, 2004

Meson and Baryon Spectroscopy at HERA

Meson Spectroscopy Overview: What is the role of GlueX in the global spectroscopy program?

Meson spectroscopy with CLAS [ CLAS12

Meson Spectroscopy and Partial Wave Analysis at CLAS

Meson spectroscopy and the ‘missing’ valence glue of QCD · Meson Spectroscopy - J. Dudek Summary photoproduction as a meson factory has not hitherto been explored it is likely

Excited light meson spectroscopy from lattice QCD · Excited light meson spectroscopy from lattice QCD With Jo ... ’, , Probe annihilation dynamics in QCD. 11 Isoscalars m s

Exclusive Meson Production CLAS and CLAS11

Meson spectroscopy

N* spectroscopy with meson photoproduction reactions

Infrared conﬁnement and meson spectroscopy

Near Infrared Spectroscopy – An Overviewmaizeandgenetics.tamu.edu/SethCMurray/Teaching/Lectures/NIRS clas… · Near Infrared Spectroscopy – An Overview Background Theory Uses

Overview of Meson Spectroscopy Experiments and Data Curtis A. Meyer Carnegie Mellon University

Meson spectroscopy with unitary coupled-channels model

Meson Spectroscopy at B factories 8 GeV e - 3.5 GeV e + BaBar Belle

Light-Meson Spectroscopy at Jefferson Labhadron.physics.fsu.edu/~crede/FILES/Presentation_PANDA-Workshop.pdfLight-Meson Spectroscopy at Jefferson Lab Volker Credé Florida State University,

Studies of N* Structure from the CLAS Meson Electroproduction Data

Deeply Virtual Compton Scattering and Pseudoscalar Meson Electroproduction with CLAS

CLAS Hadron Spectroscopy Working Group Meeting, CLAS Collaboration Meeting, June 2013