Magnetic Monopole Search at a high altitudewith 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

1931 Dirac: Quantization of electric charge Proc. R. Soc. London, 133 ( 1931) 60

Magnetic Monopoles

...3,2,1,n,2

c n eg

Dirac relation

DD gng , e2

137

2e

cg

SU(5) SU(3)C x [SU(2)L x U(1)Y]EW SU(3)C x U(1)EM

102 GeV

10-10 s10-35 s

1015 GeV

GUT MM1016 - 1017 GeV

Glashow et. al

Intermediate Mass Magnetic Monopoles (IMM)

SO(10)

1015 GeV

10-35 s

SU(4) x SU(2)L x SU(2)R

109 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 = gD B L ~ 6x1019 eV (B/3 μG)(L/300pc)

Galaxy W 6x1019 eV Neutron stars W 1020 - 1024 eV AGN W 1023 - 1024 eV

(105 ≤ M ≤ 1012 GeV)

liquid H2

(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*+ CH4 He + CH4 + e-

β < 10-4 Elastic collisions (c)

β > 10-2 Ionization (à la Bethe-Bloch) (Zeeq)2= (gβ)2 (a)

Energy losses of IMM

(b)

CR39®ρ = 1.32 g /cm3

(C12H18O7)n

A/Z = 1.877

MAKROFOL ®ρ = 1.29 g /cm3

(C16H14O3)n

A/Z = 1.896

158 A GeV 82+Pb in CR3920X Mag.

150X150 μm2

Chemical etching solutions

CR39® 0.1% dioctyl phthalate DOPρ = 1.32 g /cm3

(C12H18O7)n

150X150 μm2

SLIM Nuclear Track Detectors (NTD)

 detector type solution

  CR39 8N KOH + 1.5% alcohol 70° C 30h

strong CR39 DOP 8N KOH + 1.5% alcohol 75° C 30h

  Makrofol 6N KOH + 20% alcohol 75° C 30h

soft CR39 6N NaOH + 1% alcohol 70° C 40h

  CR39 DOP 6N NaOH 70° C 40h

The alcohol added in the etching solutionimproved the detector surface quality

Calibrations

In49+ & Pb82+ 158 A GeV CERN–SPS, Pb target

Fe26+ & Si14+ 1 and 5 A GeV BNL–AGS, CH2 target

0.41 A GeV Fe26+ and 0.29 A GeV C6+ HIMAC

 detector

type Z/βREL

[MeVcm2/g]vB

[ μm/h]

  CR39 14 200 7.2±0.4

strong CR39DOP 19 240 5.9±0.3

  Makrofol 50 2500 3.4±0.1

soft CR39 7 501.25±0.02

  CR39DOP 10 2350.98± 0.02

p-1

Survived beam

Fragments

Target

Incident ion beam

NTDNTD

Z/ = 78

Z/ = 82

Z/ = 51 60 70

78

Z/ = 10

2030 40

Z/ = 46

Z/ = 49CR39 Makrofol

SLIM layout

Area = 427 m2 (7420 stacks)Atm depth = 540 g/cm2(5230 m a.s.l.) R ~ 12.5 GVExposure t = 4.22 years

Atm Preassure ~ 0.5 atmMean Temp = 12 °CRd concentr. ~ 40-50 Bq/m3

Neutron flux = 1.8x10-2 cm-2s-1

SLIM stacks and search techniche

A = 24 x 24 cm2

t = 1.23466 g/cm2

h = 8.37 mm3

1000 μm

1450 μm

570 μm

125 μm

Thickness

STRONG

SOFT

SOFT

Slow IMM

FastIMM

Nuclear fragment

105 ≤ MIMM ≤ 1012 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 cm2

Measured with 6.3ob X 25oc MagEvent ≡ 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

negativepositiveneutral

C12H18O7

(ρ = 1.31 g/cm3)dim = 1450 μm x 1 x 1 cm2

ΦN ~ 1.8x10-12 cm-2 s-1 100 keV – 20 MeV

Zanini et al.@Chacaltaya

Statistical studies of n indiced background in CR39

area = 427 m2, t = 4.22 years, over 2π. No candidate found!

Φ ≤ 1.3x10-15 cm-2sr-1s-1, β>0.03 for IMM

SLIM final results

BACKUP SLIDES

Validazione Monte Carlo

Gauge theories of unified interactions predict MMs

Mass mM ≥ mX/G > 1016 GeV ~ 0.02 mg 1017 GeV

( Kaluza –Klein poles > 1019 GeV , SUSY > 1017 GeV )

GUT Monopoles (Gauge, Cosmic,..)

SU(5)1015 GeV

10-35 sSU(3)C x [SU(2)L x U(1)y]

102 GeV

10-9 sSU(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/r2 Magnetic field of a point Dirac monopole

Radius (cm)10-29 10-16 10-13

r few fm B ~ g/r2

Size: extended object

(b)0.0

10.0

15.0

20.0

25.0cm

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

74107408

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..