TWR trigger for slowly moving massive particles

1
TWR trigger for slowly moving massive particles

• David Hardtke
• University of California, Berkeley

• IceCube/AMANDA are largest detectors ever ? Dark
  Matter Searches
• Would like to search for particles with virial
  velocities (?10-3c)
• Slowly moving particles detectable by
  IceCube/AMANDA must
• Lose sufficient (non-Cerenkov) photonic energy to
  register in detector
• Be very massive (to reach detector) nanograms to
  milligrams
• Candidates
• Q-balls, Massive Monopoles catalyze nucleon
  decay ? pion production ? photons
• Nuclearites thermal shock ? black-body
  radiation ? photons

2
Experimental Challenge

• Detector Traversal Times (?d 500 m)
• Muon-DAQ ? 10 ?s live, 1 ms dead
• SN system ? No tracking
• Dark Noise Rate 1 kHz

Need Online Topological Trigger
3
Standard TWR trigger

• TWR team plans to implement two trigger types
• Multiplicity trigger (similar to muon DAQ)
• Volume Local Coincidence Trigger (NEXT Trigger)
• Both triggers count hits in 10 ?s window

High Threshold -- write Out multiplicity event
Low Threshold -- check For local coincidences
4
? 10-3

• At virial velocites, the particle moves 0.3 m/?s
• Typical AMANDA inter-module spacing on string is
  10-20 m (30-70 ?s)
• Typical AMANDA inter-string spacing is 30-60 m
  (100-200 ?s)
• Must assume that any dark matter yields have low
  light yield (otherwise, not good Dark Matter
  candidates)

Volume Local Coincidence concept will work, but
need larger time windows searched.
5
? 10-3

• KKST Q-ball prediction for MQ1018 GeV/c2
• 100 GeV/cm in pions (? -gt Cerenkov light)
• Total Energy deposited in detector 106 GeV
• TeV/?s (looks like series of low energy
  cascades)
• dE/dx MQ 2/3
• Theoretical Optimism ? Expect lower energy
  deposited
• Monopoles look similar (Rubakov mechanism)

6
Trigger Scheme

• More than N hits in 10 us window
• Prepare list of modules hit in time window
• Check for Local Coincidences
• Examine many consecutive time windows, look for
  particle moving with target velocities
  (5x10-4lt?lt10-2)

7
Schedule

• TWR set up for software triggering this austral
  summer
• Next year -- use simulations and random triggered
  TWR data to optimize trigger
• Velocity search range
• Local coincidence threshold
• Online cross-talk filtering?
• Fast search algorithm
• Might need slight change in TWR trigger scheme
  (data buffering) -- also required for
  IceCube-Amanda common triggering
• Goal for December 2005 Implement
  astrophysically interesting trigger that does
  not impact neutrino data rates (aim for few of
  bandwidth)

8
Physics Potential
9
Conclusions

• TWR allows AMANDA searches for slowly moving
  massive particles
• Negligible impact on core physics program
• Similar algorithm will be ported to IceCube
• IceCube better for larger (rarer) objects
• AMANDA better for smaller objects that produce
  less light

10
Nuclearites

• At very large quark (baryon) number, strange
  quark matter with uds may be absolutely stable
• Interior of neutron stars
• Nuggets produced in neutron star collisions or
  during early universe
• Characterized by Z/A ltlt 1/2
• Large mass nuclearites have nuclear densities
  (?0.15 GeV/fm3) but atomic dimensions (Rgt1 A)
• May be visible in IceCube/Amanda via
  thermodynamic shock mechanism

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De Rujula - Glashow Mechanism

• Macroscopically large (atomic dimension) massive
  particles induce expanding cylindrical thermal
  shock wave ? Blackbody Radiation
• For atomic dimension objects at virial
  velocities, T can reach several thousand Kelvin
• Total Energy Loss
• Energy in visible photons

12
What is a Q-ball?

• Coherent state of squarks, sleptons, and Higgs
  field
• Non-topological Soliton ( Solitary Wave)
• Scalar field ? carries conserved charge Q (baryon
  , lepton , etc.)
• Potential U(?) has local minima at non-zero ?

Q-ball
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Q-balls and baryogenesis

• One baryogenesis model Scalar (Affleck-Dine)
  condensate formed
• The condensate can have non-zero baryon-lepton
  number if potential is flat
• As temperature drops, symmetry broken, but lumps
  of condensate (B-balls) survive. Other parts of
  condensate decay to baryons

14
Q-balls properties

• MsSupersymmetry Breaking Scale (100-1000 GeV)
• Q-Balls stable for MQ gt1014 GeV
• Lifetime for MQ lt 1014 GeV unknown

15
Q-ball detection

• SENS (Supersymmetric Electrically Neutral
  Soliton)
• Q-ball catalyzes nucleon decay producing pions
• Similar to Rubakov monopoles, but larger
  cross-sections
• 100 GeV g-1 cm2
• IceCube can improve flux limits by 1-3 orders of
  magnitude (exact number depends on MS)
• SECS (Supersymmetric Electrically Charged
  Soliton)
• dE/dx 100 GeV/cm, but no Cerenkov light
• Glashow-DeRujlia mechanism may work for very
  large MQ
• Mica Limits probably always superior