Md. Naimuddin (on behalf of CDF and D0 collaboration) University of Delhi Recontres de Moriond
XXXVI th Recontres de Moriond Very High Energy Phenomena in the Universe 24 January 2001 Dan...
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Transcript of XXXVI th Recontres de Moriond Very High Energy Phenomena in the Universe 24 January 2001 Dan...
XXXVIth Recontres de MoriondVery High Energy Phenomena in the Universe
24 January 2001
Dan Javorsek, Ephraim Fischbach, Dave Elmore, and Tom Miller
Purdue University, West Lafayette, IN 47907
Doug Oliver and Vigdor TeplitzSouthern Methodist University,
Dallas, TX 75275
New Experimental Limits on the Existence of Strongly Interacting
Dark Matter Particles
24 January 2001Purdue University Department of Physics
Overview
• What is a SIMP?
• Motivations for SIMPs– The Dark Matter Problem– Ultra High Energy Cosmic Rays– Lightest Supersymmetric Particle
• Our Experiment
• First Results
• Future Work
24 January 2001Purdue University Department of Physics
SIMPs
• Strongly Interacting Massive Particles– Neutral Particle
– Mass > 1 GeV/c2 Mproton 1 GeV
– Bound by the strong force to a massive (high Z) stable atom (Au)
• SIMPs may manifest as an anomalous isotope
• Recent developments in particle physics and cosmology prompts searches for superheavy particles
AuX
24 January 2001Purdue University Department of Physics
Motivation: Dark Matter
• Starkmann et al., Phys. Rev. D 41,3594 (1990)• Mohapatra & Teplitz, PRL 81, 3079 (1998)
– If : ss ~ 1/Ms
– Then : SIMPs can have sufficient abundance to saturate the cosmic density or galactic halo
• SIMPs masses needed to saturate– Cosmic density
MS > 103.5 GeV– Galactic halo
MS < 100 GeV
24 January 2001Purdue University Department of Physics
Motivation: UHECR
• Ultra High Energy Cosmic Rays (UHECRs)
• Lose energy scattering with the cosmic background radiation (GZK)
• To date, we have more than 700 confirmed events above the GZK cutoff (1019 eV)
• Models of Albuquerque, Farrar, and Kolb suggest [Phys. Rev. D 59, 015021 (1998)]
10 GeV/c2 < MS < 50 GeV/c2
24 January 2001Purdue University Department of Physics
Motivation: SUSY
• Mohapatra & Nandi, PRL 79, 181 (1997)• Chacko et al., Phys. Rev. D56, 5466 (1997)• Raby, Phys. Rev. D 56, 2852 (1997)
– suggest the gluino is the lightest supersymmetric particle (LSP)
Theory Predicted SIMP Mass
Dark Matter MS < 100 GeV
Ultra High Energy Cosmic Rays
10 GeV < MS < 50 GeV
Lightest SUSY Particle6.3 GeV < MS < 100
GeV
24 January 2001Purdue University Department of Physics
TandemAccelerator
Analyzing andSwitching Magnets
Ion Source Injector MagnetGasIonizationDetector
ElectrostaticAnalyzer
The Experiment
• Use Accelerator to search for anomalously heavy isotopes of Au
24 January 2001Purdue University Department of Physics
Results
• Scanned SIMP mass rangefrom 2.8-144 GeV/c2
• Scanned both lab gold and Australian gold
• Calculated the abundance of Au nuclei with SIMPs to those without
X
Aux I
q
Au
X
det
12 )ln)(10672.2(
24 January 2001Purdue University Department of Physics
Results
0 50 100 15010
-11
10-10
10-9
MX [GeV/c2]
X/A
u
M’ = effective SIMP mass
= MX-MAu
= MS-|EB|
MX’ = 3 GeV 50 GeV 100 GeV 144 GeV
X/Au < 1.3 10-11 < 1.0 10-10 < 4.3 10-10 < 4.4 10-10
24 January 2001Purdue University Department of Physics
ResultsMohapatra et al., Phys. Rev. D 60, 115013 (1999)
SN(mb)
MX (GeV)
0.0005
0.0015
0.0042
0.012 0.032 0.09 0.25 0.69 1.9 5.3
2.7 5.9 7.9 8.3
4.3 5.7 7.7 8.1 11.1
7.1 5.5 7.5 7.9 10.9 12.1
12 5.6 7.6 8.1 8.5 12.2 12.7
19 7.5 7.9 8.3 11.3 12.5 12.9
31 7.4 7.8 8.2 8.6 12.4 12.8 13.2
50 5.7 7.7 8.1 8.5 11.5 12.7 13.1 13.6
81 5.7 7.7 8.1 8.5 8.9 11.9 13.1 13.5 14.0
132 5.7 7.7 8.1 8.5 8.9 9.3 12.2 13.5 13.9 14.3
220 6.0 8.0 8.4 8.9 9.3 9.7 12.6 13.9 14.3 14.7
24 January 2001Purdue University Department of Physics
Geological Samples
• Western Australia– 15 cm of surface using a metal detector– Exposure age 50 million years
• Northwestern Arizona– Mineral Park District (Gold Basin)– Exposure age 5 million years
• Western North Carolina– Collected from streams in the
Appalachians– South of glaciated area affected by the Ice
Age– Deposits formed 570 million years ago
24 January 2001Purdue University Department of Physics
Exotic Samples
• Long Duration Exposure Facility (LDEF)– Part of the Meteoroid and
Exposure Module– Exposed to space from 1984 to
1990– Performed 32,422 Earth orbits– Experienced ½ a solar cycle
• Iron Meteorite
• Beam dump from Brookhaven National Laboratory
24 January 2001Purdue University Department of Physics
Conclusions
• SIMP abundance must be less than 1 x 10-11
• Future Work– Increase mass scan range (up to 1
TeV/c2)– Include more diverse samples
• LDEF, Brookhaven, Meteorite, • Arizona, NC, Dentists & Jewlers
– Search in Lead and Uranium