From Colliders to Cosmic Rays 7 – 13 September 2005, Prague, Czech Republic Search for nuclearites with the SLIM detector V. Popa, for the SLIM Collaboration Search for Light Monopoles •Intermediate mass Magnetic Monopoles • Strange Quark Matter • Q-balls… The Collaboration (Bolivia, Canada, Italy, Pakistan): S.Balestra , S. Cecchini, F. Fabbri , G. Giacomelli, A. Kumar S. Manzoor , J. McDonald , E. Medinaceli , J. Nogales , L. Patrizii, J. Pinfold , V. Popa , O. Saavedra, G. Sher , M. Shahzad , M. Spurio, V. Togo, A. Velarde , A. Zanini Chacaltaya Cosmic Ray Laboratory 5230 m a.s.l The experiment Nuclear track detectors Absorber Total area ~ 440 m2 One module (2424 cm2) In four years of exposure, for a downgoing flux of particles, the SLIM sensitivity will be about 10-15cm-2s-1sr-1 Nuclear Track Detectors: CR39 and Makrofol The track-etch technique m Fast Nuclear MM fragment CR39 Aluminium Makrofol SQM nuggets =1 mm 200 A GeV S16+ or β ~ 10-2 MM Slow MM Calibrations of NTDs fragments beam target detector foils detector foils Z/b =49 In49 158 AGeV 2 faces Z/b=20 Calibrations of NTDs Reduced etch rate vs REL RELREL vs ßvsfor nuclearites ß for MMs Makrofol threshold CR39 Makrofol CR39 threshold The search technique Strong etching (large tracks, easy to detect) General scan of the surface Soft etching Scan in the predicted position measurement of REL and direction of incident particle. Up to now, no double coincidences found Strange Quark Matter E. Witten, Phys. Rev. D30 (1984) 272A. De Rujula, S. L. Glashow, Nature 312 (1984) 734 •Aggregates of u, d, s quarks + electrons , ne= 2/3 nu –1/3 nd –1/3 ns •Ground state of QCD; stable for 300 < A < 1057 rN 3.5 x 1014 g cm-3 rnuclei 1014 g cm-3 A qualitative picture… [black points are electrons] R (fm) M (GeV) 102 106 103 104 105 106 109 1012 1015 1018 Produced in Early Universe or in strange star collisions (J. Madsen, PRD71 (2005) 014026) Candidates for cold Dark Matter! Searched for in CR reaching the Earth Low mass nuclearites (strangelets) in M (GeV) - nuclear like - could be produced as ordinary CR - could be relativistic - could be ionized - cannot reach the Earth surface - maybe already seen (“Centauro” events…) d d us d s us u 300 e At least two propagation models allow them to reach the SLIM atmospheric depth. Spectator – participant (mass decrease) (Wilk & Wlodarczyk, Heavy Ion Phys. 4(1986)396 Accretion (mass increase) S. Banerjee & al., PRL 85 (2000) 1384 Important feature: Z /A « 1 10 3 Nuclei 0.5A 0.3A2/3 8A1/3 ~0.1A Z 10 2 10 10 3 10 4 A 10 5 M. Kasuya et al. Phys.Rev.D47(1993)2153 H.Heiselberg, Phys. Rev.D48(1993)1418 J. Madsen Phys. Rev.Lett.87(2001)172003 10 6 Strangelets : small lumps of SQM - ~300 < A < 106 -charged Produced in collisions of strange stars R. Klingenberg J. Phys. G27 (2001) 475 Accelerated as ordinary nuclei Mass increase during propagation => large fluxes expected at the SLIM altitude Mass decrease during propagation => smaller fluxes expected! G. Wilk et al. hep-ph/ 0009164 (2000) J. Madsen et al. Phys.Rev.D71 (2005) 014026 Assuming the “fragmentation” propagation: Input parameters highly unknown, but expected ~ 10 12 15 2 1 10 cm s sr In the “accretion” scenario, fluxes could be (much) larger (?) Which is really the lowest A for which strangelets are stable? 1 M (GeV) 31022 High mass nuclearites d e u eu d s s se u d sd s u u d - Absolutely neutral (all e- inside SQM) - Could traverse the Earth - Would produce macroscopic effects - Non interesting for SLIM (as it would not reach MACRO sensitivity) Intermediate mass nuclearites M (GeV) 1014 e d e u eu d s s se u d sds u u d - Essentially neutral (most if not all e- inside - “Simple” properties: galactic velocities, elastic collisions, energy losses… - Could reach SLIM from above - Better flux limit from MACRO: 2 10 16 cm 2s 1sr 1 for M 1014 GeV M. Ambrosio et al., Eur.Phys. J. C13 (2000) 453; L. Patrizii, TAUP 2003 Nuclearites - basics A. De Rújula and S.L. Glashow, Nature 312 (1984) 734 •Typical galactic velocities b 10-3 • Dominant interaction: elastic collisions with atoms in the medium • Dominant energy losses: dE rmed. v 2 dx 3M / 4r M 1.5ng (8.4 1014 GeV ) (e inside) 16 2 10 cm M 1 . 5 ng ( e cloud) 2/3 • Phenomenological flux limit from the local density of DM: r DM v / 2 M (km2 yr 1 (2sr 1 )) 7.8(1g / M) Arrival conditions to SLIM The velocity of a nuclearite entering in a medium with v0, after a path L becomes in the atmosphere: rmed. ( x )dx M0 L v( L) v 0 e ratm ( x ) a e Hx b a = 1.2 10-3 g cm-3; b = 8.6 105 cm; H 50 km (T. Shibata, Prog. Theor. Phys. 57 (1977) 882.) r ( x ) dx abe e 1 atm 0 (h = Chacaltaya altitude, 4275m) L H b H h b Detection conditions in SLIM preliminary results About 170 m2 of detectors with an average exposure time of 3.5 years were analyzed. Various background tracks (compatible with nuclear recoil fragments produced by C.R. neutrons) were found. No candidates found. The present flux 90% C.L. upper limit is 3.9 10 cm s sr , 15 2 1 1 for strangelets and nuclearites, but also for fast monopoles and Q-balls. perspectives Detector removal from Chacaltaya during fall Analysis completed by mid 2006 Discovery of IMMs, SQM or Q-balls??? Otherwise, significant limits in not yet explored mass regions! Nuclearites White Mt. Mt. Norikura Sea level SLIM Ohya MACRO High altitude: Underground SLIM :5300 m White Mountain: 4800 m Mt. Norikura: 2000 m Ohya : 100 hg/cm2 MACRO : 3700 hg/cm2 Light and intermediate mass MMs MACRO SLIM MACRO MACRO+SLIM Charged Q- balls AKENO, KEK : ground level ZQ = 1 MACRO : 3700 hg/cm2 undg. AMS: Space Station SLIM: 540 g/cm2 atm depth KEK AMS AKENO SLIM MACRO perspectives Detector removal from Chacaltaya during fall Analysis completed by mid 2006 Discovery of IMMs, SQM or Q-balls??? Otherwise, significant limits in not yet explored mass regions! Strong constrains, rejection/confirmation on models of strangelets production and propagation.