1. Magnetic Monopole Search at a high altitude with the SLIM (Search for Light Magnetic Monopoles) experiment http://www.bo.infn.it/slim/ Eduardo Medinaceli for the SLIM collaboration S. Balestra, S. Cecchini, M. Cozzi, M. Errico, F. Fabri, G. Giacomelli, R. Giacomelli, M. Giorgini, A. Kumar, S. Manzoor, J. McDonald, G. Mandrioli, S. Marcellini, A. Margiotta, E. Medinaceli, L. Patrizii, J. Pinfold, V. Popa, I.E. Qureshi, O. Saavedra, Z. Sahnoun, G. Sirri, M. Spurio, V. Togo, A. Velarde, A. Zanini

2. 1931 Dirac: Quantization of electric charge Proc. R. Soc. London, 133 ( 1931) 60 Magnetic Monopoles Dirac relation SU(5) SU(3) C x [SU(2) L x U(1) Y ] EW SU(3) C x U(1) EM 10 2 GeV 10 -10 s 10 -35 s 10 15 GeV GUT MM 10 16 - 10 17 GeV Glashow et. al

3. Intermediate Mass Magnetic Monopoles (IMM) SO(10) 10 15 GeV 10 -35 s SU(4) x SU(2) L x SU(2) R 10 9 GeV 10 -23 s SU(3) C x [SU(2) L x U(1) Y ] EW +… Virtual vector bosons X, Y? Electroweak Unification W, Z Virtual photons and gluons Confinement region Magnetic field of a point MM 10 -25 10 -16 10 -13 Radius (m) Produced in the Early Universe in later phase transitions De Rujula CERN-TH 7273/94, E. Huguet & P. Peter hep-ph/ 901370, T.Kephart, Q. Shafi Phys. Lett. B520(2001)313, Wick et al. Astropart. Phys. 18, 663 (2003) IMMs can be accelerated in the galactic B field to relativistic velocities W = g D B L ~ 6x10 19 eV (B/3 μG)(L/300pc) Galaxy W 6x10 19 eV Neutron stars W 10 20 - 10 24 eV AGN W 10 23 - 10 24 eV (10 5 M 10 12 GeV)

4. liquid H 2 (c) (b) (a) 10 -4 <β<10 -2 Excitation (Medium as Fermi gas) 10 -4 <β<10 -3 Drell effect M + He M + He* Penning effect He*+ CH 4 He + CH 4 + e - β < 10 -4 Elastic collisions (c) β > 10 -2 Ionization (à la Bethe-Bloch) (Ze eq ) 2 = (gβ) 2 (a) Energy losses of IMM (b)

5. CR39® ρ = 1.32 g /cm 3 (C 12 H 18 O 7 ) n A/Z = 1.877 MAKROFOL ® ρ = 1.29 g /cm 3 (C 16 H 14 O 3 ) n A/Z = 1.896 158 A GeV 82+ Pb in CR39 20X Mag. 150X150 μm 2 Chemical etching solutions CR39® 0.1% dioctyl phthalate DOP ρ = 1.32 g /cm 3 (C 12 H 18 O 7 ) n 150X150 μm 2 SLIM Nuclear Track Detectors (NTD) detector typesolution CR398N KOH + 1.5% alcohol 70° C 30h strongCR39 DOP8N KOH + 1.5% alcohol 75° C 30h Makrofol6N KOH + 20% alcohol 75° C 30h softCR396N NaOH + 1% alcohol 70° C 40h CR39 DOP 6N NaOH 70° C 40h The alcohol added in the etching solution improved the detector surface quality

6. Calibrations In 49+ & Pb 82+ 158 A GeV CERN–SPS, Pb target Fe 26+ & Si 14+ 1 and 5 A GeV BNL–AGS, CH 2 target 0.41 A GeV Fe 26+ and 0.29 A GeV C 6+ HIMAC detector typeZ/β REL [MeVcm 2 /g] v B [ μm/h] CR39142007.2±0.4 strongCR39DOP192405.9±0.3 Makrofol5025003.4±0.1 softCR39750 1.25± 0.02 CR39DOP10235 0.98± 0.02 p-1 Survived beam Fragments Target Incident ion beam NTD Z/ = 78 Z/ = 82 Z/ = 51 60 70 78 Z/ = 10 20 30 40 Z/ = 46 Z/ = 49 CR39 Makrofol

7. SLIM layout Area = 427 m 2 (7420 stacks) Atm depth = 540 g/cm 2 (5230 m a.s.l.) R ~ 12.5 GV Exposure t = 4.22 years Atm Preassure ~ 0.5 atm Mean Temp = 12 °C Rd concentr. ~ 40-50 Bq/m 3 Neutron flux = 1.8x10 -2 cm -2 s -1

8. SLIM stacks and search techniche A = 24 x 24 cm 2 t = 1.23466 g/cm 2 h = 8.37 mm 3 1000 μm 1450 μm 570 μm 125 μm Thickness STRONG SOFT Slow IMM Fast IMM Nuclear fragment

9. 10 5 M IMM 10 12 GeV > 0.03 Accessible regions in the parameter space (mass, ) for IMMs coming from above

10. IMM Energy losses in CR39 and Acceptance CR39 (strong)

11. L5 scan: 500 – 1000 X Mag L1 scan 3 X Mag, stereo microscope; scanned twice ~ 99% 20 – 40 X Mag SLIM scan Coincidence area ~ 0.5 cm 2 Measured with 6.3 ob X 25 oc Mag Event p and θ are equal within 20 %

12. Classifications of Tracks for Scanning in the SLIM NTDs Different Track Shapes as Observerd in the SLIM NTDs (a) (b) (c) (d) (e) (f) (g) (h) collinear etch-pits

13. negative positive neutral C 12 H 18 O 7 (ρ = 1.31 g/cm 3 ) dim = 1450 μm x 1 x 1 cm 2 Φ N ~ 1.8x10 -12 cm -2 s -1 100 keV – 20 MeV Zanini et al.@Chacaltaya Statistical studies of n indiced background in CR39

14. area = 427 m 2, t = 4.22 years, over 2π. No candidate found! Φ 1.3x10 -15 cm -2 sr -1 s -1, β>0.03 for IMM SLIM final results

15. BACKUP SLIDES

16. Validazione Monte Carlo

17. Gauge theories of unified interactions predict MMs Mass m M m X /G > 10 16 GeV ~ 0.02 mg 10 17 GeV ( Kaluza –Klein poles > 10 19 GeV, SUSY > 10 17 GeV ) GUT Monopoles (Gauge, Cosmic,..) SU(5) 10 15 GeV 10 -35 s SU(3) C x [SU(2) L x U(1) y ] 10 2 GeV 10 -9 s SU(3) C x U(1) EM Grand Unification: virtual X,Y Electroweak unification: W, Z Confinement region: virtual s, gluons, condensate of fermions -antifermion, 4 fermion virtual states B=g/r 2 Magnetic field of a point Dirac monopole Radius (cm) 10 -29 10 -16 10 -13 r few fm B ~ g/r 2 Size: extended object

18. (b) 0.0 10.0 15.0 20.0 25.0 cm 5.0 (a) ~2 cm G = 6.3x (d) G = 6.3x (c) G = 6.3x A Strange Event Observed in the SLIM _7408 Module 7410 7408 Layout of the SLIM modules near 7408 module. Positions of the SLIM modules inside the wooden box during the flight Bologna-La Paz and La Paz-Bologna.