Physics Prospects with the JLab 12 GeV Upgrade - PowerPoint PPT Presentation

Loading...

PPT – Physics Prospects with the JLab 12 GeV Upgrade PowerPoint presentation | free to view - id: 277820-YzRlM



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Physics Prospects with the JLab 12 GeV Upgrade

Description:

Normal Mesons qq color singlet bound states ... typical hadronic final states: f1h KKh KKppp b1p wp pppp rp ppp. high data acquisition rate ... – PowerPoint PPT presentation

Number of Views:53
Avg rating:3.0/5.0
Slides: 40
Provided by: vol48
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Physics Prospects with the JLab 12 GeV Upgrade


1
Physics Prospects with the JLab 12 GeV Upgrade
  • Elton S. Smith
  • Jefferson Lab
  • PANIC02
  • Osaka

Gluonic Excitations 3-dim view of the Nucleon
Valence Structure of the Nucleon
2
CEBAF _at_ JLab Today
  • Main physics programs
  • nucleon electromagnetic form factors (including
    strange form factors)
  • N ? N electromagnetic transition form factors
  • spin structure functions of the nucleon
  • form factors and structure of light nuclei
  • Superconducting recirculating electron
    accelerator
  • max. energy 5.7 GeV
  • max current 200 mA
  • e polarization 80
  • Simultaneous operation in 3 halls
    Lcm-2s-1
  • 2 High Resolution Spectrometers (pmax4
    GeV/c) 1039
  • 2 spectrometers (pmax7 and 1.8 GeV/c) special
    equipment 1039
  • Large Acceptance Spectrometer for e and g
    induced reactions 1034

3
(No Transcript)
4
Gluonic Excitations
Dynamical role of Glue
Confinement
5
Lattice QCD
? Flux Tube Model
From G. Bali
6
Understanding Confinement
The Ideal Experiment
The Real Experiment
7
Hybrid Mesons
8
Normal Mesons qq color singlet bound states
  • Spin/angular momentum configurations radial
    excitations generate our known spectrum of light
    quark mesons.
  • Starting with u - d - s we expect to find mesons
    grouped in nonets - each
  • characterized by a given J, P and C.

9
Quantum Numbers of Hybrid Mesons
Excited Flux Tube
Quarks
Hybrid Meson
like
10
Meson Map
Mass (GeV)
Lattice 1- 1.9 GeV 2- 2.1 GeV 0- 2.3 GeV
(L qq angular momentum)
11
Exotic Signal JPC1-
E852 p1(1600) ? h? p?
? h p?p?
? gg
M 1.60 ? 0.05 G 0.34 ? 0.06
PRL 86, 3977 (2001)
12
Families of Exotics
1- nonet
p1 IG(JPC)1-(1-)
13
Strategy for Exotic Meson Search
  • Use photons to produce meson final states
  • tagged photon beam with 8 9 GeV
  • linear polarization to constrain production
    mechanism
  • Use large acceptance detector
  • hermetic coverage for charged and neutral
    particles
  • typical hadronic final states f1h KKh
    KKppp b1p wp pppp
    rp ppp
  • high data acquisition rate
  • Perform partial-wave analysis
  • identify quantum numbers as a function of mass
  • check consistency of results in different decay
    modes

14
Coherent Bremsstrahlung
12 GeV electrons
flux
This technique provides requisite energy, flux
and polarization
photons out
electrons in
spectrometer
diamond crystal
Eg (GeV)
15
GlueX / Hall D Detector
Electron Beam from CEBAF
16
Finding an Exotic Wave
17
Detector Designed to do Partial Wave Analysis
18
3-dimensional view of the Nucleon
Deep Exclusive Scattering
19
Generalized Parton Distributions
  • GPDs provide access to fundamental quantities
    such as the quark orbital angular momentum that
    have not been accessible
  • and the GPDs unify the description of inclusive
    and exclusive processes, connecting directly to
    the normal parton distributions

20
Limiting Cases for GPDs
Ordinary Parton Distributions (D, t, x ? 0)
H0(x,0) q(x) unpolarized
Nucleon Form Factors (Sum Rules)
x P
(x-x) P
Dirac
Axial vector
P
P?D
Pauli
Pseudoscalar
21
GPDs Contain Much More Information than DIS
Quark distribution q(x)
DIS only measures a cut at ?0
Antiquark distribution q(x)
qq distribution
22
Measuring the GPDs
  • Key experimental capabilities include
  • CW (100 duty factor) electron beams
    (permits fully exclusive reactions)
  • modern detectors (permit exclusive
    reactions at high luminosity)
  • adequate energy (10 GeV to access the valence
    quark regime)
  • Measurements of the GPDs are now feasible

23
Interpretation of the GPDs
Analogy with form factors
24
3-dim picture
from Belitsky and Mueller
Elastic Scattering
Deep Inelastic
Deep Exclusive
25
Meson Production as a Filter
  • Use quantum numbers of meson to select
    appropriate combinations of parton distributions
    in nucleon.
  • Pseudo-scalars (polarized)
  • p0 Duv - ½ Ddv
  • h Duv - ½ Ddv 2Dsv
  • Vector Mesons (unpolarized)
  • rL0 u u ½ (d d) g
  • wL0 u u - ½ (d d) g
  • fL0 s s g

g
p
p
26
Program to determine GPDs
¾

¾

r
2
2
0
,
E
H
ep
ep
?
-

p
p


¾

¾

p
2
2
,
E
H
en


¾

¾
g
2
2
2
2
,
,
,
E
H
E
H
p
e


r
¾

¾

g
E
H
E
H
ep
p
e
,
,
,

r


¾

¾

p
E
en
p
e
Other Channels
r

(h,p) e D p e Nw e (L,S) K
eN
p
e
27
Deep Virtual Compton Scattering A Window on
Quark Correlations
DIS is limited by the fact that it can only
measure longitudinal distributions averaged over
all quarks in the nucleon
  • DIS corresponds exactly to the imaginary part of
    the Deep Compton Scattering amplitude
  • Add determination of the final state (by
    exclusive reactions such as DVCS) and we can
    (finally!) probe nucleon quark structure and
    correlations at the amplitude level

28
DVCS Single-Spin Asymmetry
29
Hard Meson Electroproduction (ro)
  • Physics issue map out GPDs (need to isolate sL)
  • Technique determine sL from r ?pp decay angle
    distribution
  • CLAS at 11 GeV
  • 400 hrs at L 1035 cm-2s-1

sL Q -6
sT Q -8
30
Valence Quark Structure of the Nucleon
Parton Distributions at large x
31
Enhanced Access to the DIS Regime
  • 12 GeV will access the valence quark regime for x
    gt 0.3
  • where constituent quark properties are not masked
    by the sea quarks

32
Predictions for large xBj
Proton Wavefunction (Spin and Flavor Symmetric)
33
Valence Quark Distribution
  • Physics issue
  • compare behavior of u and d quarks as xBj ? 1
  • Experimental problem
  • extract information from comparison of hydrogen
    and deuterium data
  • need to correct for nuclear effects in D
  • Solution for CEBAF upgrade
  • compare DIS off 3He and 3H (nuclear effects
    same)

34
The Neutron Spin Asymmetry A1n
  • Study of spin structure functions has been
    limited to the low-x region
  • JLab at 12 GeV with its high luminosity is a
    prime facility for measurements at large x

35
Flavor Decomposition (e,e?)/(e,e?-)
36
12 GeV Upgrade Project Status
  • Developed by CEBAF User Community in
    collaboration with JLab
  • Nuclear Science Advisory Committee, NSAC
  • plan presented during last 5-year Long Range Plan
  • recommended by NSAC for new construction
  • Plan presented to Department of Energy
  • presently waiting for CD-0 (determination of
    mission need)
  • Detailed report is being prepared to be reviewed
    by Jlab PAC in January
  • Construction
  • construction start expected in FY2007 (October
    2006)
  • 3 year construction project

37
(No Transcript)
38
CLAS Detector
Central Detector
39
SHMS - HMS Spectrometers After Upgrade
40
Physics Program at 12 GeV
Exciting
Gluonic Excitations Valence Structure of the
Nucleon 3-dim view of the Nucleon
Compelling
In view of recent progress in lattice calculations
Timely
41
Electron-Light Ion Collider Layout
Ion Source
RFQ
DTL
Snake
CCL
Snake Solenoids
IR
IR
5 GeV electrons
100 GeV light ions
Injector
5 GeV CEBAF with Energy Recovery
100 MV cryomodules
Beam Dump
Luminosity 1035cm-2s-1
Lia Merminga
About PowerShow.com