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

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 ?

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)

E/A for bulk strange quark matter (MeV)

Phase diagram for QCD Temperature Density

Quark nuggets as dark matter? Cosmological nuclearites: A<1049 (CAUSALITY) A>1040 (EVAPORATION) A>1023Ω3 (NUCLEOSYNTH.) Q-BALLS are analogous log(Baryon number)

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

”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

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

Color-Flavor Locking Stable STRANGELETS BULK Madsen, PRL 87 (2001) 172003

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

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

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

Cosmic strangelet flux Z=8, A=138 [CFL] Flux (per [year GV sqm sterad]) Source Interstellar Solar System Madsen (2005) Phys.Rev. D 71, 014026 Rigidity (GV)

Total CFL-strangelet flux Total flux (per [year sqm sterad]) No geomagnetic cutoff Interstellar Solar System Madsen (2005) Phys.Rev. D 71, 014026 Z

Total CFL-strangelet flux Total flux (per [year sqm sterad]) No geomagnetic cutoff Interstellar Solar System Madsen (2005) Phys.Rev. D 71, 014026 A Mass number

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

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 Y96673-05_1Commitment

Atlantis launch Sep. 9, 2006

ISS from STS-115 Sep. 17, 2006

Alpha Magnetic Spectrometer AMS-02 International Space Station 2008 - 2011 (or longer) PURPOSE Cosmic rays Antimatter (anti-He) Dark matter Strangelets Superconducting magnet technology

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

Courtesy Choutko (MIT)

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

The Moon as a strangelet detector

NASA gave us 15 grams of lunar soil from Apollo 11

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

Courtesy Evan Finch (Yale)

Courtesy Evan Finch (Yale)

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)

Cronin, Gaisser & Swordy (1997)

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)

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

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