1. UCI Anita meeting April 7-9, 2005 Using ANITA to Probe Extensions to the Standard Model Fenfang Wu and Steve Barwick UCI

2. UCI Anita meeting April 7-9, 2005 Using ANITA to probe physics beyond the standard model www.ps.uci.edu/~anita 8m 600 km radius, 1.1 million km 2

3. UCI Anita meeting April 7-9, 2005 Outline Overview - direct vs reflected events Simulation of reflected events Dependence of direct and reflected vs  –GZK flux, E -2 flux Identification of reflected events –Ice Topography and distance distribution Limitations to calculation of reflected event rate Probing Physics beyond the standard model –Simulation issues of new physics –Example, Micro-BH Proposal

4. UCI Anita meeting April 7-9, 2005 Reflected and Direct Events ignore ice Ignore -TIR DirectReflected

5. UCI Anita meeting April 7-9, 2005 Geometry - details (ask Fenfang)

6. UCI Anita meeting April 7-9, 2005 General Features of Reflected Events Linear dependence with cross-section- short pathlengths Smaller signals due to extra travel through ice and losses at reflection, but more solid angle - view more sky! More uncertainty with interface physics Less systematics at edge of fresnel

7. UCI Anita meeting April 7-9, 2005 Simulation of Reflected Events Use “mirror charge” to get geometry MC model assumptions –Temperature profile of ice is given by South Pole (but much more complicated than that) Much colder at transition from ice shelf to coast Underice topology over East Antarctica is better, but generally sculpted ravines from glacial flow before ice cap covered continent Rates are very sensitive to max attenuation length - 1500m controls the locations of reflected events –Specular reflected power is 10%, but adjustable –Secondary interactions occur at same location of primary and highest energy secondary or primary is selected (but lower energy nearer to bottom may be more detectable)

8. UCI Anita meeting April 7-9, 2005 Event ID : Reflected or Direct? Based on Topology and distance Develop likelihood function to separate reflected from direct events Distance (km) reflect direct Code=1.2x, E = 10 20 eV, Reflect power=10%,  =10  sm reflect direct

9. UCI Anita meeting April 7-9, 2005 Ice Thickness Maps Same orientation as previous slide

10. UCI Anita meeting April 7-9, 2005 Direct and Reflected Event Rates Reflected rates are negligible at small cross-sections Direct rates do not depend on L att Reflected rates depend sensitively on L att ESS GZK 45 day LT

11. UCI Anita meeting April 7-9, 2005 Depth Profile Comparison Black = direct Red = reflected Depth beneath snow surface (m) 10 , E =10 20 eV, L att =1500 Reflected occur near bottom, whereas direct interact near surface

12. UCI Anita meeting April 7-9, 2005 Absolute  att is useful 2L att (T)L att (T) Reflected and direct, E =10 20 eV, 10  sm Reflected =blue, Direct=maroon(?)

13. UCI Anita meeting April 7-9, 2005 LAKE ~10dB Bedrock General Reflection 35-60 dB!

14. UCI Anita meeting April 7-9, 2005 Ice-Rock Interface Consulting with Donald Blankenship and Matthew Peters, U. Texas - They map Antarctic Ice and propose to map a large fraction of E. Antarctica at 150 MHz. Calibrate reflectivity by moving from ice shelf to locations inland Ice Shelves - Good reflectivity: Ronne has saline ice below glacial ice so very lossy, Ross has good properties Reflected power varies greatly over Antarctica (losses from 10 dB to 60 dB). East Antarctica probably has good reflectivity because mostly silty smooth surfaces, some thin ice near coast, and relatively cold ice. –~35dB typical, but some regions may be 10dB

15. UCI Anita meeting April 7-9, 2005 Ice-Rock Interface-2 High reflectivity = –-1dB power : smooth ice to salty sea liquid water – -3dB power: smooth ice to freshwater liquid Medium reflectivity= –-6dB power: smooth saturated sediments (about 40% liquid water and fine grained particles) Variable reflectivity= bedrock interface –-12dB for 15% liquid groundwater within rock –-30dB for a frozen interface (most of Antarctica) –-60db for frozen interface with highly fractured ice at bottom

16. UCI Anita meeting April 7-9, 2005 Ice-Rock Interface-3 Roughness –Attenuation depends on wavelength “Radiowave Propagation”, Lucien Boithias (1987)49.

17. UCI Anita meeting April 7-9, 2005 Assessment of bottom interface Interference - “next effect” compared to variation induced by surface topology Ice temp profiles in general are much more complicated than used by Woschnagg and Price (S. Pole relatively easy place to model, and still they had problems - eg.,forgot about compression) There does seem to be hope for good regions where ice is cold, not too deep, and silty sediments smooth out interface. Need pockets of good ice… which may coincidently be associated with flowing ice off the shelf.

18. UCI Anita meeting April 7-9, 2005 Simulation of New Physics Fraction of neutrino energy that goes into cascades vs high energy leptons – sm = 0.2 for CC – secondaries boost for CC –Modify fraction of NC to CC Fraction of energy that goes into hadronic cascades vs EM cascades –EM fraction is LPM suppressed Universality of neutrino cross-section for all flavors (assumed) Local flavor ratios (1:1:1 assumed)

19. UCI Anita meeting April 7-9, 2005 Simulation of New Physics-2 Losses in atmosphere are important for very large increase in cross-section at highest energies –Horizontal events traverse 380m of water equiv. –Mean path length for 10 3  for E =10 20 eV is 200m! Near surface physics very important for direct events at large  - neutrinos do not penetrate far beneath the surface –Model Rf pulse in lower density, and boundary effects At the moment, we assume new physics affects NC and CC cross-sections identically

20. UCI Anita meeting April 7-9, 2005 Micro-Black Holes (MBH) and String-balls Cross-section depends on E Cross-section depends on model parameters –n= number of extra dimensions, [2-7] –M D = energy scale of extra dimension 1 TeV for n=6, (or 3TeV in usual defn - ask Jonathan Feng) –M BH = min. mass of micro-black hole that gives reliable calculation - ie,  r s 2 is valid (string-balls if M< M BH ), and cross-section is even larger –X min =M BH /M D

21. UCI Anita meeting April 7-9, 2005 MBH  for M D =1 TeV, x min =1 (Anchordoqui, et al, hep-ph/0307228) ANITA-GZK ~100x larger For GZK flux CC  sm

22. UCI Anita meeting April 7-9, 2005 GZK models We use this one ESS/WB ANITA most sensitive to high energy tail of GZK

23. UCI Anita meeting April 7-9, 2005 MBH Average Inelasticity Inelasticity of cascade energy –Gravitation radiation during collision so M~(0.3-0.5)E –See Yoshino and Nambu PRD 67 (2003) 024009 Phenomenology of BH decay –E_vis= 0.75*M goes into visible energy (q, g) –(1-E_vis) gravitinos, gravitational radiation –E_had= (2/3)E_vis, E_EM=(1/3)E_vis Combined average inelasticity: E_cascade ~ (3/8)E if no LPM So for BH is not so different from standard model –SM: _eff = + secondaries= 0.35

24. UCI Anita meeting April 7-9, 2005 MBH GZK Event Rates ModelDirectReflect 0.1*  sm 30.05 1*  sm 70.6 10*  sm 165 100*  sm 3023 1000*  sm 2815 BH(n=6, =0.2)128 BH(n=6, y by SM)2215 BH(n=6, =0.8)10173 Weak dependence on , stronger on 100  ~ BH (45 day LT, all neutrino flavors, 1:1:1 composition, ASim 1.2x )

25. UCI Anita meeting April 7-9, 2005 Comments on Previous Table Can use relative rates of N dir and N ref to estimate  near 10 20 eV –Small increases will be difficult unless the event rates were much higher E -2 source or higher than expected GZK flux Rates depend on L_att, so must measure this quantity better

26. UCI Anita meeting April 7-9, 2005 Suggested ANITA-lite exclusion plot Event Rates depend on  BH and neutrino flux,  Parameterize as ScaleFactor*GZK, or  = S  (ESS-GZK) S MDMD Excluded Region N=2,7Separate plot for direct and direct/reflected

27. UCI Anita meeting April 7-9, 2005 Proposal Write idea paper on how reflected events (if detectable) can be used to determine cross-section at sqrt(s) ~100 TeV –Describe idea, a few examples of power of technique –Identify unknowns and systematic concerns Rock-ice interface - reflected power Interference effects Ice temp profiles Energy resolution Angular resolution - do we have any pointing info?

28. UCI Anita meeting April 7-9, 2005 ASAP Optics Software (Breault) 300 MHz, coherent Depth = 1km Gaussian surface with 0.1m variation in height Beam at 27 deg, linear polarization, divergence is 2 deg

29. UCI Anita meeting April 7-9, 2005 Conclusions Exciting opportunity to measure cross-section at energies well above LHC –No slam-dunk, but window into new physics implies that every effort should be made to exploit this idea Still a long way to go to understand the limitations and possible payoff –Collaborate with Donald Blankenship’s group at UT to understand under ice topologies and radar reflectivities –Use Breault code to study interface quantitatively (talk to Bayan Towfiq, UCI undergrad)

30. UCI Anita meeting April 7-9, 2005 MBH Wax-Bahcall E -2 Rates ModelDirectReflect 0.1*  sm 61 1*  sm 208 10*  sm 4965 100*  sm 85220 1000*  sm 63161 BH(n=6, y= 0.2)57110 BH(n=6, y by SM)64156 BH(n=6, y= 0.8)230666 Weak dependence on s, stronger on 100  ~ BH

31. UCI Anita meeting April 7-9, 2005