Magnetic Monopole Search at a high altitude with the SLIM (Search for Light Magnetic Monopoles) experiment 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

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 s s GeV GUT MM GeV Glashow et. al

Intermediate Mass Magnetic Monopoles (IMM) SO(10) GeV s SU(4) x SU(2) L x SU(2) R 10 9 GeV 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 Radius (m) Produced in the Early Universe in later phase transitions De Rujula CERN-TH 7273/94, E. Huguet & P. Peter hep-ph/ , 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 eV AGN W eV (10 5 M GeV)

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

CR39® ρ = 1.32 g /cm 3 (C 12 H 18 O 7 ) n A/Z = MAKROFOL ® ρ = 1.29 g /cm 3 (C 16 H 14 O 3 ) n A/Z = 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

Calibrations In 49+ & Pb A GeV CERN–SPS, Pb target Fe 26+ & Si 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] CR ±0.4 strongCR39DOP ±0.3 Makrofol ±0.1 softCR ± 0.02 CR39DOP ± 0.02 p-1 Survived beam Fragments Target Incident ion beam NTD Z/ = 78 Z/ = 82 Z/ = Z/ = Z/ = 46 Z/ = 49 CR39 Makrofol

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. ~ Bq/m 3 Neutron flux = 1.8x10 -2 cm -2 s -1

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

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

IMM Energy losses in CR39 and Acceptance CR39 (strong)

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 %

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

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 ~ 1.8x cm -2 s keV – 20 MeV Zanini et Statistical studies of n indiced background in CR39

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

BACKUP SLIDES

Validazione Monte Carlo

Gauge theories of unified interactions predict MMs Mass m M m X /G > GeV ~ 0.02 mg GeV ( Kaluza –Klein poles > GeV, SUSY > GeV ) GUT Monopoles (Gauge, Cosmic,..) SU(5) GeV s SU(3) C x [SU(2) L x U(1) y ] 10 2 GeV 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) r few fm B ~ g/r 2 Size: extended object

(b) 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 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.