1. Strangelets and nuclearites—an overview
Jes Madsen
University of Aarhus, Denmark

2. Topics What are strangelets and nuclearites?
Ways to detect a cosmic ray strangelet flux
A strangelet search with AMS-02 on the International Space Station
A lunar soil strangelet search
Strangelets beyond the GZK-cutoff ?

3. Strangelets (Small Lumps of Strange Quark Matter)
Roughly equal numbers of u,d,s quarks in a single ‘bag’ of cold hadronic matter.
That u,d, quark matter is not absolutely stable can be inferred by stability of normal nuclei-but this is not true for u,d,s quark matter.
Strangelet
A=12 (36 quarks)
Z/A = 0.083
Nucleus (12C)
Z=6, A=12
Z/A = 0.5
Courtesy Evan Finch (Yale)

4. E/A for bulk strange quark matter
(MeV)

5. Phase diagram for QCD
Temperature
Density

6. Quark nuggets as dark matter?
Cosmological nuclearites:
A< (CAUSALITY)
A> (EVAPORATION)
A>1023Ω3 (NUCLEOSYNTH.)
Q-BALLS are analogous
log(Baryon number)

7. Q-balls behave like quark nuggets
Madsen, Phys.Rev.Lett. 61(1988)2909 (quark nuggets)
Phys.Lett. B246(1990)135 (baryonic Q-balls)
Phys.Lett. B435(1998)125 (supersymmetric Q-balls)
Quark nugget pollution in Galaxy => ALL NEUTRON STARS ARE STRANGE STARS
Q-ball pollution in Galaxy => ALL NEUTRON STARS ARE Q-STARS
OR: FLUXES ARE NEGLIGIBLE

8. ”Ordinary” strangelets
Witten; Farhi & Jaffe…
Shell-model vs. liquid drop model
Bulk E~A
Surface tension E~A2/3
Curvature E~A1/3
B=(145 MeV)4
mS=50, 100,… 300 MeV
Stable
Madsen, PRD 50 (1994) 3328

9. B = (145MeV)4 vs. (165MeV)4
Unstable
Stable

10. Color-Flavor Locking Stable STRANGELETS BULK
Madsen, PRL 87 (2001)

11. Strangelets have low Z/A
Heiselberg, PRD 48 (1993) 1418 [Ordinary strangelets]
Madsen, PRL 87 (2001) [CFL]
0.3A2/3
8A1/3
Nuclei
0.5A
0.1A

13. 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 ”neutron stars” are strange stars!
All mass released as strangelets with mass A

14. 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

15. Cosmic strangelet flux Z=8, A=138 [CFL]
Flux (per
[year GV
sqm sterad])
Source
Interstellar
Solar System
Madsen (2005) Phys.Rev. D 71,
Rigidity (GV)

16. Total CFL-strangelet flux
Total flux
(per [year
sqm sterad])
No geomagnetic cutoff
Interstellar
Solar System
Madsen (2005) Phys.Rev. D 71, Z

17. Total CFL-strangelet flux
Total flux
(per [year
sqm sterad])
No geomagnetic cutoff
Interstellar
Solar System
Madsen (2005) Phys.Rev. D 71, A
Mass number

18. Detecting strangelets at 1-1000 GV
Find low Z/A cosmic rays with high precision equipment in space
=>
AMS-02

20. AMS-02 Collaboration 16 Countries, 56 Institutes, 500 Physicists
FINLAND
RUSSIA
HELSINKI UNIV.
UNIV. OF TURKU
I.K.I.
ITEP
KURCHATOV INST.
MOSCOW STATE UNIV.
DENMARK
NETHERLANDS
UNIV. OF AARHUS
ESA-ESTEC
NIKHEF
NLR
GERMANY
RWTH-I
RWTH-III
MAX-PLANK INST.
UNIV. OF KARLSRUHE
KOREA
USA
A&M FLORIDA UNIV.
JOHNS HOPKINS UNIV.
MIT - CAMBRIDGE
NASA GODDARD SPACE FLIGHT CENTER
NASA JOHNSON SPACE CENTER
UNIV. OF MARYLAND-DEPRT OF PHYSICS
UNIV. OF MARYLAND-E.W.S. S.CENTER
YALE UNIV. - NEW HAVEN
EWHA
KYUNGPOOK NAT.UNIV.
FRANCE
ROMANIA
CHINA
BISEE (Beijing)
IEE (Beijing)
IHEP (Beijing)
SJTU (Shanghai)
SEU (Nanjing)
SYSU (Guangzhou)
SDU (Jinan)
GAM MONTPELLIER
LAPP ANNECY
LPSC GRENOBLE
ISS
UNIV. OF BUCHAREST
SWITZERLAND
ETH-ZURICH
UNIV. OF GENEVA
TAIWAN
SPAIN
CIEMAT - MADRID
I.A.C. CANARIAS.
ITALY
ACAD. SINICA (Taiwan)
CSIST (Taiwan)
NCU (Chung Li)
NCKU (Tainan)
NCTU (Hsinchu)
NSPO (Hsinchu)
ASI
CARSO TRIESTE
IROE FLORENCE
INFN & UNIV. OF BOLOGNA
INFN & UNIV. OF MILANO
INFN & UNIV. OF PERUGIA
INFN & UNIV. OF PISA
INFN & UNIV. OF ROMA
INFN & UNIV. OF SIENA
MEXICO
UNAM
PORTUGAL
LAB. OF INSTRUM. LISBON
16 Countries, 56 Institutes, 500 Physicists
~ 95% of AMS is constructed in Europe and Asia
Y _1Commitment

22. Atlantis launch
Sep. 9, 2006

23. ISS from STS-115
Sep. 17, 2006

24. Alpha Magnetic Spectrometer AMS-02
International Space Station (or longer)
PURPOSE
Cosmic rays
Antimatter (anti-He)
Dark matter
Strangelets
Superconducting magnet technology

25. The AMS superconducting magnet coils are fully assembled:
Volume 35 cu. ft., Field 8,600 Gauss, Weight 2 tons

28. Courtesy Choutko (MIT)

29. Detecting strangelets at 100 MeV
Find low Z/A ”nuclei” in lunar dust with high precision accelerator mass spectrometer
=>
Lunar Soil Strangelet Search

30. The Moon as a strangelet detector

31. NASA gave us 15 grams of lunar soil from Apollo 11

32. Wright Nuclear Structure Lab Yale LSSS-collaboration:
Sandweiss, Majka, Finch, Ashenfelter,
Chikanian, Han, Heinz, Parker (Yale)
Fisher, Monreal (MIT)
Madsen (Århus)

33. Courtesy Evan Finch (Yale)

34. Courtesy Evan Finch (Yale)

35. Lunar soil flux limits Flux (m2 sr yr) -1
Predicted flux (Madsen 05)
Flux (m2 sr yr) -1
Current Preliminary Limit
AMS-01 interesting event
Goal for Z= 8 (also sensitive to nearby charges)
1 event sensitivity in AMS-02
Baryon number A
Evan Finch (Yale)

36. Cronin, Gaisser & Swordy (1997)

37. Strangelets could also explain Ultra-High Energy Cosmic Rays Madsen & Larsen, PRL 90 (2003) 121102
Avoids the acceleration problem of ordinary UHECR candidates (HIGH Z)
Avoids the GZK cut-off from interaction with 2.7K cosmic microwave background (HIGH A)

38. Eliminating the GZK-cutoff
Photo-pion production cut-off at
b) Photo-disintegration at
Photo-pair-production above

39. Summary Strangelets have low Z/A
CFL and non-CFL strangelets differ wrt. Z
Experimental verification/falsification of
Strangelet existence
Realistic from AMS-02 [2008-?]
Possible from lunar soil search [2006-7]
(A,Z)-relation (CFL or ordinary)
Optimistic, but not impossible from AMS-02 or lunar soil search
Possible explanation of UHECR’s
Can play similar games for Q-balls