VLVTs as Magnetic Monopole and Nuclearite Detectors

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VLV?Ts as Magnetic Monopole and Nuclearite
Detectors

• -The ANTARES case-

V. Popa, for the ANTARES Collaboration
INFN, Sezione di Bologna
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The main reason of VLV?Ts is to do Neutrino
Astronomy
They could also look for exotica present in
cosmic rays monopoles, nuclearites, etc
Proper trigger logic needed!
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1. Magnetic Monopoles
Magnetic charge g n gD, n 1,2,3,? and gD
137/2 e
GUT monopoles
Two categories
Intermediate mass monopoles
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GUT Monopoles (Gauge, Cosmic,..)
Gauge theories of unified interactions predict
MMs
Slowly moving!

• Mass mM mX/G gt 1016 GeV 0.02 mg ? 1017 GeV
  

• Size extended object

r ? few fm B g/r2
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Proton decay (Callan Rubakov)
Assuming ?Mon 10-3, in water, 10 cm
10m 30 ?s - 3 ms
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GUT MMs detectable trough the Cherenkov light
emitted by the proton decay charged secondaries,
between 3 104 105 photons with ? 300 600
nm for each event.
A trigger should require multiple coincidences in
a relatively large time window, and the
efficiency of such a search depends strongly on
the assumed value of ?0 and ?Mon
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• A very naive estimation of the ANTARES
  sensitivity to GUT MMs
• assume only MMs near to the vertical
• (?? ? 0.3 sr)
• require at least 3 hits along the same line
• no background included

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Intermediate mass MMs (105 - 1012 GeV)1994
De Rujula CERN-TH 7273/94E. Huguet P. Peter
hep-ph/ 901370 T.W. Kephart, Q. Shafi Phys.
Lett. B520(2001)313Wick et al. Astropart. Phys.
18, 663 (2003) Produced in the Early Universe
after GUT phase transitions ex.
(Shafi) M 1010 GeV , g 2 gD ,
no p-decay catalysis IMMs can be accelerated in
the galactic B field to relativistic velocities
T gD B L 6 x 10 10 GeV (B/3x10-6 G)
(L/300pc) Galaxy
T ? 6 x 1010 GeV Neutron stars
T ? 1011 - 1015 GeV AGN
T ? 1014 - 1015 GeV
Could they produce the highest energy cosmic ray
showers E gt 1020 eV ?
1015 GeV
109 GeV
SU(4) x SU(2) x SU(2)
SU(3) x SU(2) x U(1)
SO(10)
10-35 s
10-23 s
Relativistic!
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Intermediate mass MMs in VLV?Ts
- By the monopole and by ? electrons for
Cherenkov light production
- By ? electrons for
ANTARES, as other VLV?Ts, is optimized for the
Cherenkov light produced by upward going
particles relativistic IMMMs are expected from
above
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Direct Cherenkov emission (? gt 0.74)
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Cherenkov light from ? rays (knock-on electrons),
?Mongt0.51
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Total number Cherenkov photons 300 lt ? lt 600 nm
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Candidate events selection and fast MM trigger

• Natural choice adapt the 3D ? trigger by
  enlarging the causality time window and the
  maximum event duration

• Most of the background from multi-? events the
  amount of data to record would be too large to
  handle

• Further requirements
• at least 5 Optical Modules on at least 2 lines,
  for ?Mongt 0.74
• at least 20 OMs from which at least 12 with more
  than 4 hits, for 0.51 lt ?Monlt 0.74

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Expected ANTARES sensitivity to relativistic MMs
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2. NuclearitesE. 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 lt A lt 1057

rN ? 3.5 x 1014 g cm-3 rnuclei ? 1014 g cm-3
A qualitative picture
black points are electrons
R (fm) 102 103 104
105 106 M (GeV) 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

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Intermediate mass nuclearites
M (GeV)
1022
M. Ambrosio et al., Eur.Phys. J. C13 (2000) 453
L. Patrizii, TAUP 2003
1010
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Nuclearites - basics
A. De Rújula and S.L. Glashow, Nature 312 (1984)
734

• Typical galactic velocities ? ? 10-3
• Dominant interaction elastic collisions with
  atoms in the medium
• Dominant energy losses
• Phenomenological flux limit from the local
  density of DM

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A little more on dE/dx
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Arrival conditions to the depth of ANTARES
The velocity of a nuclearite entering in a medium
with v0, after a path L becomes
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Velocities in ANTARES
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Light production / cm of path
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How many photons reach the OMs?
We assume Aeff 440 cm2 and ?att 50m.
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M.C. simulation for an isotropic flux of
down-going nuclearites in ANTARES
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ANTARES acceptance for down-going nuclearites
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At least 1 OM (academic!)
At least 2 OMs from 2 different clusters
At least 3 OMs from 3 different clusters
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Which would be the ANTARES sensitivity in 1 year?
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Possible background sources
The time information is very useful!
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Possible detection strategy
based on the L1 ANTARES triggers either large
pulses from a single PM, either coincidences
between at least two PMs in the same storey.
Look for 2-3 L1 trains of length 1?s ? ? t ?
1ms, with a relative delay of few ?s
Off-line analysis
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How an event would look like?
Assume M 1016 GeV and ?0 10-3, downgoing
? at ANTARES 9.75 10-4
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Distribution of hits
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The light emitted by the expanding shock waves is
isotropic
Could a downgoing nuclearite be seen by the
Cherenkov monopole trigger?
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-Slow monopole trigger Trigger Efficiency, S
algorithm, ? 10-3
Efficiencies still need to be estimated, the
trigger could be improved
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Conclusions
Once proper triggers implemented, ANTARES (as
most other VLV?Ts) could look for

• Slow ( ?lt10-3 ) GUT monopoles (Cherenkov
  emission after catalyzed proton decays)

• Relativistic downgoing IMMMs (direct or
  indirect Cherenkov emission)

• Nuclearites arriving with ? gt 10-4 (thermal
  radiation)

other exotica?

• Q-balls they would catalyze p decays (as GUT
  MMs) and produce heated tracks (like
  nuclearites) ?