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Introduction Introduction

November 2002 November 2002

Good News Good News

House Senate House Senate

References All of the above can be downloaded from our website Go to “Documents” References All of the above can be downloaded from our website Go to “Documents” - top of left frame:

Periodic Table n n p p Periodic Table n n p p

Spectroscopy of the Atom Spectroscopy of the Atom

Discovery of the Hadrons In the 50’s and 60’s physicists discovered over 100 elementary Discovery of the Hadrons In the 50’s and 60’s physicists discovered over 100 elementary particles in cosmic ray showers and accelerators. Almost all of these were short-lived and were classified as mesons or baryons. Bubble chamber photo Typical lifetime: 10 -23 s Baryons have half-integer spin and obey Pauli Exclusion Principle (PEP). They are fermions. Mesons have integer spin and do not obey the PEP. They are bosons.

Discovery of Elementary Particles in showers of Cosmic Rays Discovery of Elementary Particles in showers of Cosmic Rays

Spectroscopy of Hadrons Baryons proton Mesons neutron π meson Spectroscopy of Hadrons Baryons proton Mesons neutron π meson

Standard Model Electromagnetic force explains atoms Ordinary Matter Strong Force binds quarks Electroweak force Standard Model Electromagnetic force explains atoms Ordinary Matter Strong Force binds quarks Electroweak force explains radioactivity

Subatomic Sizes Subatomic Sizes

Color Color

No Free Quarks Color Field: Because of self interaction, confining flux tubes form between No Free Quarks Color Field: Because of self interaction, confining flux tubes form between static color charges

Lattice Calculations and Flux Tubes From G. Bali: quenched QCD with heavy quarks Lattice Calculations and Flux Tubes From G. Bali: quenched QCD with heavy quarks

Flux Tube Breaking Flux Tube Breaking

Exciting the Flux Tube Normal meson: flux tube in ground state Excited flux tube Exciting the Flux Tube Normal meson: flux tube in ground state Excited flux tube There are two degenerate first-excited transverse modes with J=1 – clockwise and counter-clockwise – and their linear combinations lead to JPC = 1– + or JPC=1+ – for the excited flux-tube

The Light Quarks and Light Mesons JPC = 0– + 0++ 1– – 1+ The Light Quarks and Light Mesons JPC = 0– + 0++ 1– – 1+ – 2++ … Allowed combinations JPC = 0– – 0+ – 1– + 2+ – … Not-allowed: exotic Expect to find nine mesons with the same J, P, C - a nonet

Quantum Numbers for Hybrid Mesons Quarks Excited Flux Tube Hybrid Meson like Exotic like Quantum Numbers for Hybrid Mesons Quarks Excited Flux Tube Hybrid Meson like Exotic like So only parallel quark spins lead to exotic JPC

QCD and Spectroscopy QCD and Spectroscopy

Exotic Hybrids Will Be Found More Easily in Photoproduction Quark spins already aligned There Exotic Hybrids Will Be Found More Easily in Photoproduction Quark spins already aligned There are strong indications from theory that photons will produce exotic hybrid mesons with relatively large cross sections. Production of exotic hybrids favored. Almost no data available

Coherent Bremsstrahlung flux This technique provides requisite energy, flux and polarization 12 Ge. V Coherent Bremsstrahlung flux This technique provides requisite energy, flux and polarization 12 Ge. V electrons Incoherent & coherent spectrum 40% polarization in peak Linearly polarized photons out collimated electrons in spectrometer diamond crystal tagged with 0. 1% resolution photon energy (Ge. V)

Tagger Magnet Tagger Magnet

Aerial View of Jefferson Lab Aerial View of Jefferson Lab

Linac Linac

Cryomodule Cryomodule

Arcs Arcs

Helium Factory Helium Factory

Upgrade Plan Upgrade Plan

Detector Detector

Lead Glass Calorimeter & Magnet arrives in Bloomington Lead Glass Calorimeter & Magnet arrives in Bloomington

Electronics PMT Bases: FADCs: Electronics assembly robotics facility to be installed at IU in Electronics PMT Bases: FADCs: Electronics assembly robotics facility to be installed at IU in June

TOF Prototype $70 K from JLab TOF Prototype $70 K from JLab

Magnetic Shielding Helmholtz coils built by undergrads last year - upgraded this year new Magnetic Shielding Helmholtz coils built by undergrads last year - upgraded this year new power supplies

History ü ü ü Collaboration Founded in 1998 Workshops (latest in May 2003) 4 History ü ü ü Collaboration Founded in 1998 Workshops (latest in May 2003) 4 th Design Report Collaboration meetings Regular conference calls Management plan o Collaboration Board Reviews ü ü ü PAC 12 Cassel Review APS/DNP Town Meeting NSAC LRP PAC 23

Computational Challenge • Glue. X will collect data at 100 MB/sec or 1 Petabyte/year Computational Challenge • Glue. X will collect data at 100 MB/sec or 1 Petabyte/year - comparable to LHC-type experiments. • Close collaboration with computer scientists has started and the collaboration is gaining experience with processor farms.

Conclusions The spectroscopy of light quark mesons is on the verge of making important Conclusions The spectroscopy of light quark mesons is on the verge of making important contributions to answering a fundamental question: What is the nature of confinement in QCD? We welcome additional collaborators - theory and experiment and bright, enthusiastic undergrads