Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos Chih‐Ching Chen Collaboration with Chia-Yu Hu and Pisin Chen LeCosPA & National Taiwan University ICRC 2011, Beijing Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 1Chih-Ching Chen

UHE Neutrino Search by Radio Signal Experiment: ANITA, RICE, FORTE, LUNASKA, NuMoon, ARA,ARIANNA Method: Askaryan radiation Signal model(Far field approx.): -EM shower :ZHS model(Zas, Halzen,Stanev92) -Hadronic shower : AVZ model (Alvaer- Muniz,Zas) Chih-Ching Chen Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 2

Underground Radio Detector for Neutrino Search ~1km Chih-Ching Chen Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 3

Lepton Signal ν e Hadronic shower(~10s meter) +EM shower(~100 meter ) ν μ or ν τ : Hadronic shower (~10s meter) + mu/Tau propagation decay to electron -> hadronic/EM shower Hadonic shower EM shower/ Hadronic shower EM shower Hadronic shower Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 4Chih-Ching Chen

10^19eV Hadronic Shower in Ice 10m Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 5Chih-Ching Chen

Electron 10^19eV in ice 10^19eV e- 140m Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 6Chih-Ching Chen

Proton

EM Shower

Mu, Tau Propagation μ, τ energy loss in medium (GQRS, Dutta, Bugaev…..) Bremsstrahlung processes e+ e−-pair production processes Photonuclear processes Stochastic caustic energy loss Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 9Chih-Ching Chen

5x10 18 eV Mu Propagate in Ice Photonuclear loss Pair production loss Photonuclear loss Pair production loss Bremsstrahlung loss EM shower Hadronic shower Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 10Chih-Ching Chen EM shower

10 19 eV Tau propagate in ice Photonuclear loss Pair production loss Hadronic shower EM shower Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 11Chih-Ching Chen

Energy Loss of EeV muon Hadronic shower EM shower At ultra-high energies, muon energy loss consists of two components: Shower signal moving charges from ionization and pair production

Energy loss of EeV Muon At 5EeV Muon (th:10 -3 ): dE/dx total = dE/dx shower +dE/dx cont dE/dx total ~ 1.25 EeV/km dE/dx shower ~ 1 EeV/km dE/dx cont. ~ 0.25 EeV/km ~ 2.5 TeV/cm Based on shower simulations, we know that the number of moving net charges from continuous energy loss is ~10 5 e - Typical eV hardronic shower max has ~ 10 9 e - They are comparable!

eV -> 6*10 7 e*m Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos Chih-Ching Chen

Estimate of the mu trace signal If trace signal is detected from 1km away, then 1km +/- 2 degree -> 100m trace 10 5 x100m = 10 7 (e*m) (on-cone signal) A eV hadronic shower from 1km away would produce ~6*10 7 (e*m) (off-cone signal; bipolar shape) Conclusion: We should be able to see passing EeV muons within km (100% trigger). Both cosmic ray moun & neutrino generated muon Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 15Chih-Ching Chen

Ultra-High Energy Muon, Tauon in Ice Hadonic shower EM shower Hadonic shower EM shower With LPM effect Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 16Chih-Ching Chen

Neutrino Flavor Behavior Electron νMuon νTau ν N.C.Hardornic Shower ~20%E ~10m C.C.Hardornic Shower ~20% ~10m C.C. lepton Electron EM shower Muon Propagation Tau Propagation ~80%E ~100m(LPM)~10s km All charge current neutrino signal with huge shower(s) Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 17Chih-Ching Chen

Conclusion The shower size from c.c. UHE ν inter. is huge The signal from UHE muon, tau is multi –bang with a long track The detected flavor probability is ν μ > ν τ >ν e Cherenkov signal in time domain is studied. Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 18Chih-Ching Chen

Back…… Chih-Ching Chen Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 19

Cherenkov Radiation Simulation by Finite Difference Time Domain Advantage of FDTD: First principle, Time domain, Global simulation. w/o approximation (Near field) Shower is cylindrical symmetry. Radiation is polarized ( Er, Ez,H φ ) Net current Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 20Chih-Ching Chen

E - R relation of 100MHz speed up Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 21Chih-Ching Chen

Electron shower signal Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 22Chih-Ching Chen

Radiation Gauge Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 23Chih-Ching Chen

A(x,t) j(x’,t’) θ J T (x’,t’) Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 24Chih-Ching Chen

Shower size 100 m, R = 600 m Charge A(t) vector potential Electric field y Electric field x Shape of two pol. E-field Is different Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 25Chih-Ching Chen

Shape varies with detection angle θ = θc θ = θc-+θ Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 26Chih-Ching Chen

On Cherenkov angle Shower position Detected time Log(A(t’)) Log(A(t)) Near-Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos 27Chih-Ching Chen