COSMIC RAY STRANGELETS

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COSMIC RAY STRANGELETS

• Jes Madsen
• University of Aarhus, Denmark

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Cosmic ray strangelets

• What are strangelets ?
• Could a significant cosmic ray strangelet flux
  exist and be measured ?
• A strangelet search with the Alpha Magnetic
  Spectrometer (AMS-02) on the International Space
  Station .
• Strangelets as ultra-high energy cosmic rays ?

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Ordinary strangelets

• Witten Farhi Jaffe
• Shell-model vs. liquid drop model
• Bulk EA
• Surface tension EA2/3
• Curvature EA1/3

B(145 MeV)4
mS50, 100, 300 MeV
Madsen, PRD 50 (1994) 3328
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B (145MeV)4 vs. (165MeV)4
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CFL-strangelets
Madsen, PRL 87 (2001) 172003
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Strangelets have low Z/A
Heiselberg, PRD 48 (1993) 1418 Ordinary
strangelets
Madsen, PRL 87 (2001) 172003 CFL
0.3A2/3
8A1/3
Nuclei 0.5A
0.1A
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Strangelet charge

• Vacuum polarisation dominates at high A gt lower
  Z
• Madsen Larsen,
• PRL 90 (2003) 121102

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Cronin, Gaisser Swordy (1997)
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Measuring strangelets at 1-1000 GV

• Find low Z/A cosmic rays with high precision
  equipment in space
• gt
• AMS-02

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Alpha Magnetic Spectrometer AMS-02
International Space Station 2007/08 for 3-5 years

• PURPOSE
• Cosmic rays
• Antimatter (anti-He)
• Dark matter
• Strangelets

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Choutko (MIT)
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Strangelets from strange star binary collisions

• 1 binary neutron star collision per 10.000
  years in our Galaxy
• Release of 10-6 solar masses per collision
• Basic assumptions
• SQM absolutely stable!
• All mass released as strangelets with mass A
  (fluxes for mass A give lower limit of flux if
  mass spectrum of masses below A)

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Strangelet propagation

• Acceleration in supernova shocks etc
• Source-flux powerlaw in rigidity
• Diffusion in galactic magnetic field
• Energy loss from ionization of interstellar
  medium and pion production
• Spallation from collision with nuclei
• Escape from galaxy
• Reacceleration from passing shocks

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Cosmic strangelet fluxZ8, A138 CFL
Flux (per year GV sqm sterad)
Source
Interstellar
Solar System
Madsen (2004) PRELIMINARY
Rigidity (GV)
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Cosmic strangelet fluxZ8, A138 CFL
Flux above R (per year sqm sterad)
Interstellar
Solar System
Source
Madsen (2004) PRELIMINARY
Rigidity (GV)
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Total CFL-strangelet flux
Total flux (per year sqm sterad)
No geomagnetic cutoff
Interstellar
Solar System
Madsen (2004) PRELIMINARY
Z
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Total CFL-strangelet flux
Total flux (per year sqm sterad)
No geomagnetic cutoff
Interstellar
Solar System
Madsen (2004) PRELIMINARY
A
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Cronin, Gaisser Swordy (1997)
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Is there a GZK-cutoff ?
Abbasi et al. (High Resolution Flys Eye
Collaboration), PRL 92 (2004) 151101
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Why are strangelets interestingas ultra-high
energy cosmic rays?Madsen Larsen, PRL 90
(2003) 121102

• Avoids the acceleration problem of ordinary
  UHECR candidates
• Avoids the GZK cut-off from interaction with 2.7K
  cosmic microwave background

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Why are strangelets interestingas ultra-high
energy cosmic rays?Madsen Larsen, PRL 90
(2003) 121102

• ZSTRANGELET gtgt ZNUCLEUS possible
• ?
• Better acceleration in known sources
• (EMAX RMAX Z RMAX magn.field x size)
• Rigidity R p/Z ( E/Z if relativistic)

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Hillas-plot for E(max)1020eV
Stecker/Olinto (2000)
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Hillas-plot for E(max)1020eV
Strangelet Z104
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Why are strangelets interestingas ultra-high
energy cosmic rays?Madsen Larsen, PRL 90
(2003) 121102

• Less susceptible to GZK-cut-off from
  high-Lorentz-factor interactions with 2.7K
  CMB-photons because of
• High A
• Low Z/A

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Eliminating the GZK-cutoff

• Photo-pion production cut-off at
• b) Photo-disintegration at
• Photo-pair-production above

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Plausible sources for UHECRs (Anchordoqui et
al. Int.J.Mod.Phys.A18 (2003) 2229

• Supernovae explosions 147, 148.
• Large scale Galactic wind termination shocks
  149.
• Pulsars (neutron stars) 150.
• Active galactic nuclei (AGNs) 151.
• BL Lacertae (BL Lac) a sub-class of AGN 152,
  153.
• Spinning supermassive black holes associated
  with presently inactive quasar remnants154, 155
• Large scale motions and the related shock waves
  resulting from structure formation in the
  Universe 157 such as accretion flow onto galaxy
  clusters and cluster mergers 158, 159.
• Relativistic jets and hot-spots produced by
  powerful radiogalaxies. 161, 162, 163.
• The electrostatic polarization fields that
  arise in plasmoids produced in planetoid impacts
  onto neutron star magnetospheres 166.
• Magnetars pulsars with dipole magnetic fields
  approaching 1015 G 167, 168, 169 appear also
  as serious candidates 170, 171.
• Starburst galaxies 172, 173, 174.
• MHD winds of newly formed strongly magnetized
  neutron stars 175.
• Gamma ray burst (GRB) fireballs 176, 177, 178,
  179.
• Strangelets, stable lumps of quark matter,
  accelerated in astrophysical environments 180.
• Hostile aliens with a big CR gun 181.

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Conclusions

• Strangelets have low Z/A
• CFL and non-CFL strangelets differ wrt. Z
• Experimental verification/falsification of
• Strangelet existence
• Realistic from AMS-02 2007/8 for 3-5 years
• Possible from lunar soil search experiment
  Sandweiss et al. (Yale) Fisher et al. (MIT)
  Madsen (Aarhus) 2004
• (A,Z)-relation (CFL or ordinary)
• Optimistic, but not impossible from AMS-02 or
  perhaps lunar soil search

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Detection of UHECRs (Anchordoqui et al.
Int.J.Mod.Phys.A18 (2003) 2229
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