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

UCI Anita meetingApril 7-9, 2005

Using ANITA to Probe Extensions to the Standard Model

Fenfang Wu and Steve Barwick

UCI

UCI Anita meetingApril 7-9, 2005

Using ANITA to probe physics

beyond the standard model www.ps.uci.edu/~anita

8m

600 km radius,1.1 million km2

UCI Anita meetingApril 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

UCI Anita meetingApril 7-9, 2005

Reflected and Direct Events

ignore ice Ignore -TIR

Direct Reflected

UCI Anita meetingApril 7-9, 2005

Geometry - details (ask Fenfang)

UCI Anita meetingApril 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

UCI Anita meetingApril 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)

UCI Anita meetingApril 7-9, 2005

Event ID : Reflected or Direct?• Based on Topology and distance

• Develop likelihood function to separate reflected from direct events

Distance (km)

reflectdirect

Code=1.2x, E= 1020 eV, Reflect power=10%, =10sm

reflect direct

UCI Anita meetingApril 7-9, 2005

Ice Thickness MapsSame orientation as previous slide

UCI Anita meetingApril 7-9, 2005

0.1

1

10

100

1000

0.1 1 10 100 1000

GZK direct and reflected rates

L_att

2*L_att

(L_att):ref

(2L_att):ref

Event Rates (relative units)

Cross_Section

Direct and Reflected Event Rates

Reflected rates are negligible at small cross-sections

Direct rates do not depend on Latt

Reflected rates depend sensitively on Latt

ESS GZK45 day LT

UCI Anita meetingApril 7-9, 2005

Depth Profile Comparison

Black = direct

Red = reflected

Depth beneath snow surface (m)

10, E =1020 eV , Latt=1500Reflected occur near bottom, whereas direct interact near surface

UCI Anita meetingApril 7-9, 2005

Absolute att is useful

2Latt (T)Latt (T)

Reflected and direct, E=1020eV, 10sm

Reflected =blue, Direct=maroon(?)

UCI Anita meetingApril 7-9, 2005

LAKE ~10dB

Bedrock

General Reflection35-60 dB!

UCI Anita meetingApril 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

UCI Anita meetingApril 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

UCI Anita meetingApril 7-9, 2005

Ice-Rock Interface-3

• Roughness – Attenuation depends on wavelength

“Radiowave Propagation”,Lucien Boithias (1987)49.

UCI Anita meetingApril 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.

UCI Anita meetingApril 7-9, 2005

Simulation of New Physics• Fraction of neutrino energy that goes into cascades vs high

energy leptons– <y>sm = 0.2 for CC– secondaries boost <y> 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)

UCI Anita meetingApril 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 103 for E=1020 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

UCI Anita meetingApril 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]– MD = energy scale of extra dimension

• 1 TeV for n=6, (or 3TeV in usual defn - ask Jonathan Feng)

– MBH = min. mass of micro-black hole that gives reliable calculation - ie, rs

2 is valid• (string-balls if M< MBH), and cross-section is even larger

– Xmin=MBH/MD

UCI Anita meetingApril 7-9, 2005

MBH for MD=1 TeV, xmin=1(Anchordoqui, et al, hep-ph/0307228)

AN

ITA

-GZ

K

~100x largerFor GZK flux

CCsm

UCI Anita meetingApril 7-9, 2005

GZK models

We use this oneESS/WB

ANITA most sensitive to high energy tail of GZK

UCI Anita meetingApril 7-9, 2005

MBH Average Inelasticity <y>

• 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 <y> for BH is not so different from standard model– SM: <y>_eff = <0.2>+ secondaries= 0.35

UCI Anita meetingApril 7-9, 2005

MBH GZK Event Rates

Model Direct Reflect0.1*sm 3 0.05

1*sm 7 0.6

10*sm 16 5

100*sm 30 23

1000*sm 28 15

BH(n=6,<y>=0.2) 12 8

BH(n=6, y by SM) 22 15

BH(n=6, <y>=0.8) 101 73

Weak dependence on , stronger on <y>

100 ~ BH

(45 day LT, all neutrino flavors, 1:1:1 composition, ASim 1.2x )

UCI Anita meetingApril 7-9, 2005

Comments on Previous Table

• Can use relative rates of Ndir and Nref to estimate near 1020 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

UCI Anita meetingApril 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

MD

Excluded Region

N=2,7 Separate plot for direct and direct/reflected

UCI Anita meetingApril 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?

UCI Anita meetingApril 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

UCI Anita meetingApril 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)

UCI Anita meetingApril 7-9, 2005

MBH Wax-Bahcall E-2 Rates

Model Direct Reflect0.1*sm 6 1

1*sm 20 8

10*sm 49 65

100*sm 85 220

1000*sm 63 161

BH(n=6, y= 0.2) 57 110

BH(n=6, y by SM) 64 156

BH(n=6, y= 0.8) 230 666

Weak dependence on s, stronger on <y>

100 ~ BH

UCI Anita meetingApril 7-9, 2005