Constraints for New Physics from Matter Effects on Neutrino Oscillation Minako Honda (Ochanomizu Univ.) and Naotoshi Okamura (YITP) Yee Kao (Virginia Tech.) Alexey Pronin (Virginia Tech.) Tatsu Takeuchi (Virginia Tech.) based on hep-ph/0602115 hep-ph/0603268 hep-ph/0611xxx Joint Meeting of Pacific Region Particle Physics Communities (@Honolulu, Hawaii) 2006.10.31

Today’s Theme Do interactions between neutrinos and matter due to “New Physics” have an effect on neutrino oscillations?? p e- n -beam e- n p 2. Can such effects be measured experimentally?? & be used to constrain “New Physics”??

Introduction

Universality Violation in NC In many models beyond the SM, the universality of the couplings can be violated through radiative corrections. Matter effect beam (a) charged current interaction etc... processes ex) MSSM with (b) neutral current interaction lead to the NC universality violation

Direct exchange of New Particles W.Buchmuller et.al. PLB191,442(1987) New Physics that can contribute to neutrino oscillations: Supersymmetric R-parity violating couplings Z’ in Gauged B-(Le+L+L)　with  Z’ in Topcolor assisted Technicolor Leptoquarks that couple different generations etc. E.Ma, PLB433,74(1988) C.T,Hill, PLB345,483(1995) etc.. W.Buchmuller et.al. PLB191,442(1987) e.g.)

Experimental constraints on universality violation in NC

The experimental constraints ~invisible decay width~ invisible LEP @ CERN LEP/ OPAL, DELPHI, L3, ALEPH, SLD NO CONSTRAINT individual decay No information is available on the individual decay widths into each flavor

The experimental constraints ~individual~ CHARM, CHARM II @ CERN (’80s) Z couplings to neutrinos PLB180,303(1986), PLB320,203(1994) cf ) Z couplings to charged leptons LEP/ OPAL, DELPHI, L3, ALEPH, SLD 0.9-1.2 LEP invisible decay width (total width is constrained.)

The theoretical possibility of universality violation in many models The weakness of the current experimental bounds PLB180,303(1986), PLB320,203(1994) CHARM, CHARM II It would be interesting to analyze the effect of such a violation on neutrino oscillations.

Plan of Talk Introduction Matter effect effective potentials for neutrinos in matter W and Z exchange effective mixing angles and oscillation probabilities When Neutral Current (NC) universality is violated Can we see ? (A hypothetical experiment) Fermilab NuMI beam ⇒ Hyper-Kamiokande detector (1Mt) Constraints on "New Physics” (e.g. leptoquarks,…) Summary

Matter Effect effective potentials effective Hamiltonian

The effective potentials (W & Z exchange) charged current interaction in ordinary matter neutral current interaction

The effective Hamiltonian U:MNS matrix CC NC derived from universality violation in Neutral Current interaction central value of CHARM : measure of universality violation in NC ： effective mixing matrix ： effective mass-squares

Using the “Jacobi method”, … mixing angles oscillation probabilities Using the “Jacobi method”, …

effective mixing angles (normal hierarchy) : violation factor in NC (details in our paper)

effective mixing angles (inverted hierarchy) : violation factor in NC (details in our paper)

Survival Probabilities ( )

The oscillation probabilities ( L=9,120km ) normal hierarchy inverted hierarchy atm</4 @17GeV @17GeV 40% 40% oscillation dip neutrino beam energy [ GeV ] neutrino beam energy [ GeV ]

The oscillation probabilities ( L=9,120km ) normal hierarchy inverted hierarchy neutrino beam energy [ GeV ] neutrino beam energy [ GeV ]

The oscillation probabilities ( L=9,120km ) normal hierarchy inverted hierarchy atm</4 @17GeV @17GeV 40% 40% oscillation dip neutrino beam energy [ GeV ] neutrino beam energy [ GeV ]

Can be measured experimentally ? one example “Fermilab– HyperK”

to Japan from Japan(J-PARC) small value () large matter effect high energy (E~O(10)GeV) very long base-line (L~O(10,000)km) to Japan from Japan(J-PARC) Fermilab-Japan

Fermilab (NuMI) Hyper-Kamiokande [ L~9,120 km ] HK (1Mt) 9,120km ~732x12 17GeV NuMI Beam no oscillation Main Injector @ Fermilab MINOS @Soudan We can expect a non-negligible event rate 732km Fermilab

The expected number of events @ HK after 5 years of data taking (1Mton) 4000 3500 3000 2500 number of events 2000 17GeV 1500 oscillation dip 1000 We can expect the green line to be clearly distinguishable from the blue or pink lines. 600 500 5 10 15 20 25 30 neutrino beam energy [ GeV ]

The constrains on universality violation  2 / 14dof (8GeV-22GeV) 100 much tighter constraints than that from CHARM and CHARMII 10years 80 5years 3years 60 1year 40 99%C.L. 95%C.L. 20 90%C.L. -0.025 0.025 -0.03 -0.02 -0.01 0.01 0.02 0.03 ~0.005 ~0.015

Constraints on “New Physics” Leptoquarks Z’ Gauged B-(Le+L+L) with 

W.Buchmuller et.al. PLB191,442(1987) Lower bounds on Leptoquark masses 1. Leptoquarks S : scalar, V : vector, subscripts : dim of SU(2) rep. W.Buchmuller et.al. PLB191,442(1987) Lower bounds on Leptoquark masses dependence 0.65

2. Z’ Gauged B-(Le+L+L) with  dependence on Z’ mass E.Ma, PLB433,74(1988), etc.. dependence on Z’ mass Lower bounds on Z’ mass -0.005 0.005 5.5TeV

Lower limit on LHC LHC Gauged B-(Le+L+L), with  LEP/HERA Fermilab-to-HyperK LHC Gauged B-(Le+L+L), with  LEP and SLD Fermilab-to-HyerK LHC Fermilab to hyper-kamiokande experiment, can lead to a “marked improvement”, are comparable to the LHC result, and can be used as a “complimentary test”.

oscillation probability Fermilab Hyperkamiokande experiment Summary We investigated the matter effect on neutrino oscillation from universality violation in neutral current interactions. The violation effects normal inverted mixing angle oscillation probability L=9,120 km 17GeV This result is highly sensitive to the value of sin2(223) Fermilab Hyperkamiokande experiment If sin2(223) is as small as 0.92, the current 90% lower bound, a 5-year measurement of survival spectrum could place a model independent constraint on NC universality violation at the 1% level.

Fermilab HyperKamiokande experiment A constraint on , can potentially place a strong constraint on possible “New Physics”. Leptoquarks Z’; Gauged B-(Le+L+L) with , etc… Fermilab HyperKamiokande experiment The indirect probe of these “new particles” can improve the existing bounds compete with the direct searches @LHC If these particles is discovered @LHC can serve as an “independent” and “complimentary” test of the LHC result.

Back Up Slides

The effective potentials charged current interaction neutral current interaction Fierz tran. 2 2 ■ニュートリノの前方散乱振幅の実数成分を，物質がニュートリノに作用するポテンシャルエネルギーVと考える． : electron number density : neutron number density

The energy dependence of the effective mass squared differences normal hierarchy neutrino beam energy [ GeV ] [eV2] inverted hierarchy neutrino beam energy [ GeV ] [eV2]

The energy dependence of the effective mixing angles (neutrino) normal hierarchy neutrino beam energy [ GeV ] [degree] inverted hierarchy neutrino beam energy [ GeV ] [degree]

shift of effective mixing by  Sum up the calculation, : violation factor in NC neutrino anti-neutrino normal hierarchy is shifted by inverted (details in our paper) In the region of

average matter density Matter Profile depth (FNALHK) density (FNALHK) + average matter density

leptoquark many leptoquarks today, only S2 and V3, the others are in our paper

Z’ boson gauged B-(Le+L+L ) with (++ = 3) also, Topcolor Assisted Technicolor has Z’

SUSY ijk are already constrained »O(10-2), R-parity violation ijk are already constrained »O(10-2), from lepton decays at tree level.