1. DOE Germantown, June 23, 20051 of 25 Saltdome Shower Array (SalSA) A GZK Neutrino Detector For High Energy Physics & Particle Astrophysics David Saltzberg (UCLA) Peter Gorham ( University of Hawaii at Manoa) Gary Varner (University of Hawaii at Manoa) representing the SalSA collaboration

2. DOE Germantown, June 23, 20052 of 25 SALSA Collaboration Kernfysisch Versneller Instituut (Netherlands) Deutsches Elektronen Synchrotron (Germany) Louisiana State University University of Kansas University of Utah Endeavour Corporation University of DelawareUniversity of HawaiiU.C.L.A. S.L.A.C. and Stanford University Ohio State Univesity UC Irvine UC Berkeley and LBNL University of Minnesota UT Austin Washington University

3. DOE Germantown, June 23, 20053 of 25 Livingston (via Panofsky) Plot UHE Cosmic Rays don’t go on plot because cross-section already saturated UHE neutrino cross section is 10 -7 protons  room for new physics enhancements LHC SalSA (E CM ~100 TeV) 2010 1 PeV 1 EeV ILC How do we enter this region?

4. DOE Germantown, June 23, 20054 of 25 Particle Physics at the Energy Frontier High energy can be a energy-frontier beam: 15-150 TeV center of momentum particle physics Beyond LHC search for large extra dimensions micro-black-hole production TeV strings Std. model Large extra dimensions Anchordoqui et al. Astro-ph/0307228 GZK

5. DOE Germantown, June 23, 20055 of 25 A “GZK neutrino beam” must be available Neutrinos at 10 17-19 eV required by standard-model physics Whatever Auger finds, GZK neutrinos must be there. sees cutoff  our standard flux calculation does not see cutoff  sources are local, probably even more neutrinos (possibly, topological defects!) It’s iron  Neutrinos from spallation neutrons must be there. galactic extragalactic

6. DOE Germantown, June 23, 20056 of 25 Where we might be in just 5 years… ANITA: Discovery of ~10 GZK neutrinos IceCube Discovery of bottom-up sources Discovery of ~ 3 GZK neutrinos Auger Discovery of a few GZK neutrinos ?

7. DOE Germantown, June 23, 20057 of 25 ! Why we are here today Auger: Tau neutrino decay events ~1 GZK event per year? SalSA sensitivity, 3 yrs live 70-230 GZK neutrino events ANITA sensitivity, 45 days total: ~5 to 30 GZK neutrinos IceCube: high energy cascades ~1.5-3 GZK events in 3 years A large sample of GZK neutrinos using radio antennas in a 12 £ 12 array of boreholes natural Salt Domes

8. DOE Germantown, June 23, 20058 of 25 Probing an extreme regime for particle physics l, p nucleon xp Extreme regime: More likely to scatter off of bottom sea than down valence. GZK This is not HERA HERA tests proton structure to x~10 -4 (& only 10 -2 at “high” Q 2 ) UHE probe proton structure to x~10 -8 at high Q 2

9. DOE Germantown, June 23, 20059 of 25 Measuring cross section up to E CM =150 TeV 30% Cross Section measurement with SalSA easily achievable using Earth as a filter near horizon Not dependent on GZK shape or absolute intensity Angular resolution even for non- contained events is sufficient. Anomalous cross sections from large extra dimensions etc. at E cm =150 TeV would be clearly visible.

10. DOE Germantown, June 23, 200510 of 25 Particle Physics in Neutrino Sector GZK neutrinos are the “longest baseline” neutrino experiment: Longest L/E (proper time) for: extra admixtures & anomalous decays SUN: L/E ~ 30 m/eV GZK: L/E ~ 10 9 m/eV Measured flavor ratios of e :  :   can identify non- standard physics at source  e :  :   ! (5-6):1:1 Neutrino decay leaves a strong imprint on flavor ratios at Earth

11. DOE Germantown, June 23, 200511 of 25 Neutrinos for Astroparticle physics: The only useful messengers >100 TeV Photons lost above 30TeV: pair production on IR &  wave background Protons & Nuclei: scattered by B-fields or GZK process at all energies But the sources extend to 10 9 TeV If not particle physicists, who? 7 orders of magnitude of energy will remain unexplored.  attenuation length (Megaparsecs) scale size of Local Group Every new energy band yields major discoveries domain of neutrino dominance   IR,CMB,URB ! e + + e -

12. DOE Germantown, June 23, 200512 of 25 How to go beyond km 3 Neutrinos by cosmic accelerators: IceCube et al. Volume £ solid-angle ~ 10 km 3 -sr ~3 GZK neutrino events over lifetime Size determined by atten ~ 100m and cost. GZK neutrinos Essentially guaranteed to be there Need Volume £ solid-angle approaching 1000 km 3 -sr (Teraton) Need a detection with atten ~500m (w.e.)

13. DOE Germantown, June 23, 200513 of 25 The Askaryan Effect UHE event will induce an e/  shower: In electron-gamma shower in matter, there will be ~20% more electrons than positrons. Compton scattering:  + e - (at rest)   + e - Positron annihilation: e + + e - (at rest)   +  lead e-e- In solid material R Moliere ~ 10cm. >>R Moliere (microwaves), coherent  P  N 2

14. DOE Germantown, June 23, 200514 of 25 Heritage of PIs’ Related Experiments GLUE Goldstone, radio telescopes and the Moon first limits on >100 EeV neutrinos published Phys. Rev. Lett. (2004) FORTE Satellite observations of Greenland ice published in Phys. Rev. D (2003) ANITA Balloon borne observations of Antarctic ice First data from Anita Lite (2003) Best limits on >10 EeV neutrinos to be submitted to Physical Review letters Accelerator measurements Argonne and SLAC Attracted scientists to the technique Published in Phys. Rev. Lett. (2001) +to appear in Phys. Rev. D (2005) Salt Dome Measurements in situ Published in NIM (2002)

15. DOE Germantown, June 23, 200515 of 25 Funding Heritage DOE Funding (1999-2005...) made GLUE, Forte, ANITA, Accelerator Experiments, and Salt Dome Measurements possible: DOE OJI (Outstanding Jr. Investigator awards) Saltzberg and Gorham DOE ADRP (Advanced Detector Research Program) DOE University Programs (tasks originated with OJI’s) NASA Research Opportunities in Space Science (for ANITA) University intramural support (UH, UCLA, Caltech President’s Fund)

16. DOE Germantown, June 23, 200516 of 25 Accelerator Characterization of Askaryan Effect 200 cm 0 cm

17. DOE Germantown, June 23, 200517 of 25 Radio Coherence: Quadratic Growth + Absolute Intensity Shows amplitude expected from detailed simulations (egs/ Geant + Maxwell’s equations) GZK

18. DOE Germantown, June 23, 200518 of 25 Ultra-wideband data on Askaryan pulse 2000 & 2002 SLAC Experiments confirm extreme coherence of Askaryan radio pulse 60 picosecond pulse widths measured for salt showers. Unique signal reduces background, simplifies triggering, excellent timing for reconstruction.

19. DOE Germantown, June 23, 200519 of 25 SalSA Simulations Currently on third generation of several independently developed simulations GLUE (Goldstone) ANITA (Antarctic Impulsive Transient Antenna)  SALSA simulations...

20. DOE Germantown, June 23, 200520 of 25 SalSA simulations A 2.5 km 3 array with 225 m spacing, 12 2 =144 strings, 12 3 =1728 antenna nodes, 12 antennas per node, dual polarization ==> V eff  ~400 km 3 sr w.e. at 1 EeV Threshold 1000 hits at 10 EeV Rate: at least 20 events per year from rock-bottom minimal GZK predictions

21. DOE Germantown, June 23, 200521 of 25 Angular resolution For GZK energies: 0.1 o achieved for contained events--inside the array 1 o achieved for external events 250 m outside of array

22. DOE Germantown, June 23, 200522 of 25 Cherenkov polarization tracking Radio Cherenkov: polarization measurements are unique Cherenkov radiation is 100% linearly polarized

23. DOE Germantown, June 23, 200523 of 25 Neutrino Flavor/Current ID Simulations show NC/CC and Flavor ID to be effective on large subset of SalSA events 80-90% efficiency on neutral vs. charged-current selection above 1 EeV 30-50% of CC events will get first-order flavor ID above 1 EeV ~2 km 10 18 eV  e, ,  Neutral Currents (19%) Single Deep-Inelastic Hadronic Shower e Charged Current (27%) EM shower at primary vertex  L.P.M. elongation  Charged Current (27%) 2 nd ary showers: - brem & p.p. - photonuclear  Charged Current (27%) 2 nd ary showers: - mainly photonuclear

24. DOE Germantown, June 23, 200524 of 25 Existing Neutrino Limits and Potential Future Sensitivity RICE limits for 3500 hours livetime GLUE limits 123 hours livetime ANITA sensitivity, 45 days total: ~5 to 30 GZK neutrinos IceCube: high energy cascades ~1.5-3 GZK events in 3 years Auger: Tau neutrino decay events ~1 GZK event per year? SalSA sensitivity, 3 yrs live 70-230 GZK neutrino events Salsita: 4 strings 3 events per year Salsita 3 years

25. DOE Germantown, June 23, 200525 of 25 Plan of Attack First Proposal (~$4M, see next half of talk) Need to confirm O(1km w.e.) attenuation length low noise environment operability of hardware Plan Single borehole in 3-4 candidate domes + analysis Add 2 more boreholes to measure propagation For best dome, add 4 th borehole A simple 4-borehole prototype array will see 2-3 events/year from minimal GZK models Second Proposal ($50-100M) the full 12 £ 12 array; built out from the prototype.

26. DOE Germantown, June 23, 200526 of 25 continued by Gorham (Part II)... BACKUP SLIDES FOLLOW

27. DOE Germantown, June 23, 200527 of 25 Neutrino interactions in the Standard Model np e e np W /E/E /E 0.36 Ghandhi, Quigg, Reno, Sarcevic

28. DOE Germantown, June 23, 200528 of 25 Particle Astrophysics/Cosmology Cosmic ray E max, the maximum acceleration energy UHECR flux vs. redshift to z = 15-20 (eg. WMAP early bright phase) Independent sensitivity to dark energy density,   Exotic (“Top-down”) sources; GUT-scale decaying particles from big-bang relics

29. DOE Germantown, June 23, 200529 of 25 Heritage from other SALSA collaborators SALSA collaborators have a range of relevant experience Generally mid-career, active, accomplished, and experienced Amanda (optical detection in Antarctic Ice) & IceCube RICE (radio detection from within Antarctic ice) Auger (distributed cosmic-ray detectors) SAUND and other acoustic detection measurements Decades of experience with Oil Drilling industry Several decades of balloon-borne cosmic-ray experiments Theory and calculation of Askaryan Effect Decades of experience with Oil Drilling industry Accelerator-based, frontier particle physics Gamma-ray astronomy Two U.S. National Labs Significant European interest

30. DOE Germantown, June 23, 200530 of 25 Neutrinos: The only useful messengers at >PeV energies Photons lost above 30 TeV: pair production on IR &  wave background Charged particles: scattered by B-fields or GZK process at all energies But the sources extend to 10 9 TeV ! Conclusion: Study of the highest energy processes and particles throughout the universe requires PeV- ZeV neutrino detectors Region not observable In photons or Charged particles

31. DOE Germantown, June 23, 200531 of 25 GZK neutrino sensitivity details, 1 yr 2 independent MC calculations: UCLA & UH UCLA: Saltzberg 2002 SPIE; also 2005 Nobel symposium Simplified 10x10 strings, 10 antenna nodes per string Did not truncate dome, so high energies extended UH: Gorham et al. Phys.Rev. D 2005, in press 12x12 strings, 12 nodes with realistic trigger sims, salt dome truncated Lower trigger threshold Even 4-string array sees GZK events in 1 year!

32. DOE Germantown, June 23, 200532 of 25 Neutrino interactions in the Standard Model np e e np W /E/E /E 0.36 Ghandhi, Quigg, Reno, Sarcevic

33. DOE Germantown, June 23, 200533 of 25 Topological Defects Possible “relic” particles (dubbed X) due to symmetry breaking phase transitions in the early Universe: Masses at the GUT scale (M X ~10 25 eV). By why don’t these decay in 10 -40 sec? Confine in “topological defects”  stable until destroyed/ annihilate NO COSMIC ACCELERATOR NEEDED: “top-down” scenario X  jets  mesons  neutrinos X  leptons or even all neutrinos

34. DOE Germantown, June 23, 200534 of 25 Topological Defects Some specific models Bhattacharjee, Hill, Schramm PRL 69, 567, (1992) Protheroe & Stanev PRL 77,3708 (1996) Sigl, Lee, Bhattacharjee, Yoshida PRD 59,043504 (1998) Barbot, Drees, Halzen, Hooper, PLB 555, 22 (2003) Basic ideas Were attractive to circumvent GZK cutoff for UHE cosmic rays. Topological defects could be monopoles, superconducting cosmic strings, domain walls Generally these models produce hard neutrino spectrum: ~ E -(1-1.5) “bottom-up” scenarios are more steeply falling: E -2 to E -4 not ruled out by lower energy telescopes constrained by MeV—GeV isotropic photon fluxes Neutrino flux vs. energy sensitive to source evolution vs. z of TD’s.

35. DOE Germantown, June 23, 200535 of 25 Neutrino Telescopes for Direct Monopole Detection Monopoles: Dirac: The presence of even one monopole explains electric charge quantization Monopoles are typically part of GUTs Masses typically of order GUT scale but in some models M mp could even be as low as ~10 14 eV. Observation of monopoles would be revolutionary for HEP Parker bound (10 -15 cm -2 s -1 sr -1 ) c.f. UHECR>10 20 eV (~10 -21 cm -2 s -1 sr -1 ) other direct MP searches barely approach Parker bound Caveat: if monopoles catalyze proton decay then (lack of) neutron star heating provides extremely strong limit.

36. DOE Germantown, June 23, 200536 of 25 Neutrino Telescopes for Direct Monopole Detection Intergalactic magnetic fields sheets (~100 nG over 50 MPc) could accelerate monopoles to energies of ~5 £ 10 24 eV Light monopoles would be relativistic so are candidates for radio Cherenkov detection Parker bound (10 -15 cm -2 s -1 sr -1 ) c.f. UHECR>10 20 eV (~10 -21 cm -2 s -1 sr -1 ) other direct MP searches, generally worse than Parker bound Relativistic monopoles mimic particle with large charge: at least Z~68 produce EM showers along path by pair-production, photo-nuclear continuously produces shower along its path  unique signature WKW estimate F<10 -18 cm -2 s -1 sr -1 for a km 3 detector for 1 year. SalSA could do much better: sensitive for M mp up to 10 23 eV, far beyond production at accelerators. Flux limit better than typical searches

37. DOE Germantown, June 23, 200537 of 25 Polarization tracking Measured with dual-polarization embedded bowtie antenna array in salt

38. DOE Germantown, June 23, 200538 of 25 Estimated SalSA Energy threshold E thresh < 300 PeV (3 x 10 18 eV) best for full GZK spectral measurement Threshold depends on average distance to nearest detector and local antenna trigger voltage above thermal noise V noise = k T  f T sys = T salt +T amp = 450K  f of order 200 MHz 225 m spacing gives 30 PeV Margin of at least 10 £ for GZK neutrino energies