The 1998 DOE posters
The plots will be put here as the finalized versions become available.
The text and captions are exactly from the poster. Words like (sigma)
(pion) indicate that the Greek letter was printed.
Text are not complete yet.
Poster 1 Title: The Experiment
Plot: Updated Selex logo jpeg or postscript
Title: E781 Goals
High Statistics Charm Baryon Physics
with 650 GeV (sigma)- and (pion)- beams
- Comprehensive Study of Weak Decay Systematics
1. Precision comparision of lifetimes of all four stable states.
2. Semi-leptonic decay comparison for all stable states.
3. Uniform Dalitz plot analysis capability for most states.
4. Excellent particle ID for Cabibbo-suppressed modes.
- Strong Interaction Characteristics
1. Compare production by (sigma)- and (pi)- beams:
A-dependence vs. xF
2. Measure excited state characteristics.
3. Search for polarization effects.
- Primakoff Physics
1. Search for hybrid meson states qqg.
2. Measure hadron EM structures (form factors,
radiative width, polarizability).
- Search for Exotic States
1. Doubly-charmed baryons or penta-quarks.
2. Production of narrow, massive baryons from (sigma)- beam.
Title: E781 Data
Subtitle: (sigma)/(pion) seperation using Beam Transistion Radiation Detector
Plot: BTRD showing pi and sigma seperation at 600 GeV postscript
Table: SELEX data sets (negative, sigma, proton)
Plot: Data taking, live interactions postscript
Plot: E781 layout postscript
Poster 2 Title: Crucial Performance Factors
Title: Vertex Definition
Subtitle: Clean Definition of Production Targets
Plot: Primary vertex positions for five targets, plus boxes for physical size of targets postscript
Caption: Yellow boxes are target sizes. Black line is data.
Subtitle: Primary and Secondary Vertex Resolution
Plot: Sigma (z error) distribution of primary and secondary vertices postscript
Caption: Average primary vertex resolution = 270 microns. Average secondary vertex resolution = 560 microns.
Title: Momentum-Independent Mass Resolution
Plot: D0 mass resolution versus D0 momentum postscript
Title: Excellent (pi)/K/p Identification
Text: Strong particle identification (RICH, TRD, Pb glass) for hadrons and electrons will reduce systematics in decay physics analyses.
Plot: ETRD, pions and electrons postscript
Caption: Left plot is tracks identified by the RICH as pions. Right plot is tracks consistent with electrons, identified by either the RICH or photon.
The SELEX Phototube RICH Detector
Plot: RICH lay
- Radiator: 10m long with neon gas
- Photocathode: 2848 phototubes
- Mirror: 16 hexagon shaped spherical mirrors
1. Mean number of photons detected per ring = 14
2. N0 = 104/cm
3. Ring radius resolution = 1.2%
- Results were published in FERMILAB-Conf-97/210-E and will be submitted to NIM
Plot: Ring radii for kaons and pions at 100 GeV
Plot: Ring radii for particle seperation versus momentum.
postscript for last three plots.
Poster 3 Title: Charm Characteristics
Title: Example (lambda)c Event
Text: This event has a 650 GeV (sigma)- beam track which interacts in the last carbon target. The primary vertex is drawn, with the beam track and five outgoing tracks. The secondary vertex is a 380 GeV (lambda)c (xF=0.6) that decayed 2.2 cm downstream of the primary vertex, into a 154 GeV proton, 153 GeV kaon, and a 74 GeV pion. All three decay tracks are identified in the RICH detector.
Subtitle: Vertex View
Plot: Seed display of target region postscript
Caption: Boxes around primary and secondary vertex are three sigma errors.
Subtitle: Overall View
Plot: Seed display of detector (targets through M2 PWC) postscript
Subtitle: RICH view
Plot: Seed display of RICH detector postscript
Title: Preliminary E781 Raw Charm Signals
Plot: Yellow plots of D0, D+, Ds, Lc postscript
Poster 4 Title: Preliminary Analysis Results
Title: Baryon Beams Make Baryons, Not Anti-Baryons
Caption: For the top row, yellow plots are (lambda)c+, the blue plots are (lambda)(bar)c-.
Plot: Fernanda's plots of particle production for sigma, pion, and proton postscript
Caption: For the bottom row, yellow plots are D-, the blue plots are D+.
Text: Charm production by (pi)-, (sigma)- and p beams at 650 GeV show significant differences in particle/antiparticle ratios. The baryon preference is very large for baryon beams. We expect to contribute significantly to the understanding of charm hadroproduction.
Title: Expected Precision Lifetime Measurements
Plot: Uncorrected lifetime resolution for D0 early version postscript
Uncorrected Proper Decay Curve
Text: A preliminary D0 lifetime study demonstrates excellent proper-time resolution (~ 25 fs) in large xF production. We expect to contribute to charm lifetime analyses, especially for the short-lived states.
- 1. Sample: L/(sigma) > 8, no decays in material, uncorrected for acceptance
- 2. Simple exponential curve - (chi)(squared)/ndof = 39.1/25
- 3. Proper time resolution <= 25 fsec.
Title: What's Next
- 1. Complete the analysis code for the charm-strange baryons.
- 2. Establish the final SELEX yields.
- 3. Understand SELEX trigger issues to decide if there is a physics case to run again in 1999.