Neut rino Propert ies Which Probe Physics Beyond t he St andard - - PowerPoint PPT Presentation

Neut rino Propert ies Which Probe Physics Beyond t he St andard Model

A.B. Balant ekin Universit y of Wisconsin

Hawaii05 Double Beta Decay and Neutrino Mass Workshop

Neut rino Magnet ic Moment

. . ) ( 2 1

5 int

c h F L

i ij ij j

+ + =

αβ αβ

ψ γ ε β σ ψ

ij ij ij

ε β µ − ≡

∑ ∑

−

=

j i ij L iE li l

e U E L

2 2

| | ) , , ( µ ν µ

ν

ν ν

Neut rino mixing: νf 〉 = ∑i Uf iνi〉 Magnet ic moment operat or: µ σ ∝ ∑i〈νi µνe〉 2 = 〈νeµt µνe 〉 Dirac magnet ic moment : µt = µ Maj orana magnet ic moment : µT = -µ

diagonal Dirac magnet ic moment

Neut rino Magnet ic Moment Symmet ry Principles ⇒ µν ∝ mν

St andard Model

Combined solar, react or, and at mospheric experiment s imply a def init e limit on neut rino magnet ic moment µ ≥ (4 x 10-20) µB

Physical Processes wit h a Neut rino Magnet ic Moment

ν-e scat t ering Spin-f lavor precession Plasmon decay Neut rino decay

weak magnet ic gv = 2 sin2θW+ 1/ 2 +1/ 2 f or elect ron neut rinos gA =

• 1/ 2 f or elect ron ant ineut rinos

µν=10-12µB µν=10-11µB µν=10-10µB

elect roweak

weak only SuperK: µν ≤ (3.6 x 10-10 )µB at 90%C.L. SuperK + KamLAND: µν ≤ (1.1 x 10-10)µB at 90%C.L. addit ional µν<10-10µB µν=10-10µB

weak only µν = 9 x 10-11µB µν < 9 x 10-11µB at 90% C.L. MUNU React or Experiment f or magnet ic moment

Fut ure possibilit ies? Bet a-beams? SNS ?

Observat ional limit s on µν

νR’s are produced in magnet ic moment scat t ering

• Core-collapse supernovae:

Lat t imer and Cooperst ein; Barbieri and Mohapat ra. I f µν is suf f icient ly large t he prot o-neut ron st ar can cool f ast er since right - handed component s are st erile. µ≥ 10-12µB would be inconsist ent wit h t he

• bserved cooling t ime of

SN1987A.

• Early Universe: Morgan.

Dirac νR increase t he ef f ect ive degr ees of f reedom alt ering neut rino count ing t hrough big-bang nucleosynt hesis yields. (Not so f or t he Maj orana case since ant ipart icles are already count ed).

Bound f rom t he red-giant st ars (Raf f elt ) A large enough neut rino magnet ic moment implies enhanced plasmon decay rat e: γ→νν. Since t he neut rinos f reely escape t he st ar t his is t urn cools a red giant st ar f ast er delaying helium ignit ion. µν = (3 x 10-12) µB

Balant ekin, Loret i, Pakvasa, Raghavan. Spin-f lavor precession changes neut rino helicit y. I f t he neut rinos are of Maj orana t ype t his yields a solar ant ineut rino f lux. Kamland and SNO bounds on solar ant ineut rino f lux: ϕant ineut rino ≤ 3 x 10-4 ϕB8-neut rino

Spin-f lavor precession Dirac neut rinos

Maj orana neut rinos

Locat ions of t he SFP and MSW resonances in t he sun

f or t he limit ing case of Nn= 0, one get s

A.B. Balant ekin and C. Volpe, Phys. Rev. D72, 033008 (2005)

Solar magnet ic f ields

• St andard Solar Model requires B <

108 G.

• Helioseismology: I f B >

107 G, sound speed prof ile would deviat e f rom t he observed values Turck- Chieze.

• Solar neut rino f lux variat ions wit h heliographic

lat it ude may imply magnet ic f ields Caldwell.

Dirac Maj orana

P=0.1 P=0.9 Cl-det ect or Ga-det ect or

A.B. Balant ekin, P. Hat chell, F. Loret i, Phys. Rev. D41, 3583 (1990)

SNO Salt Result s , Balant ekin and Yuksel, PRD 68, 113002 (2003)

Af t er t he recent KamLAND result s announced at NEUTRI NO2004

Balant ekin, et al., PLB 613, 61 (2005)

For t hese paramet ers t he dif f erence bet ween MSW

• nly and SFP+MSW is less

t han 10-5.

• µ = 10-11 µB
• B = 105 G
• δm2 = 8 x 10-5 eV2
• t an2θ = 0.4

A.B. Balant ekin and C. Volpe, Phys. Rev. D72, 033008 (2005)

Conclusions

• Neut rino magnet ic moment is known t o be in

t he range (9 x 10-11) µB ≥ µ ≥ (4 x 10-20) µB The widt h of t his range represent s physics beyond t he st andard model.

• The ef f ect of µν on solar neut rino f lux is
• miniscule. Even a f ield as large as 105 G and

magnet ic moment 10-11 µB would change t he

• bserved solar neut rino f lux in part per 105.