Neutrinos. Overview. Pauli postulates Neutrino Discovery of neutrino flavours. Neutrino Interactions. Neutrino mass. Neutrino oscillations

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1 Nutrnos Ovrvw Paul postulats Nutrno Dscovry of nutrno flavours Elctron, muon and tau nutrnos Nutrno Intractons Cross sctons Nutrno mass Drct masurmnt Nutrno oscllatons Lpton flavour volaton Formalsm Solar nutrnos Homstak, Supr-K and SNO Atmosphrc nutrnos Supr-K Dscovry of Nutrno Mass nutrno oscllatons Cosmology Nuclar and Partcl Physcs Franz Muhm

2 Paul s Lttr Partcl Physcs n 930 Only 3 knowns fundamntal partcls: -, p, γ Contnuous nrgy spctrum of - n bta dcay A Z X A Z X ν Paul postulats Nutrno Dar radoactv Lads and Gntlman dsprat rmdy to sav th law of consrvaton of nrgy that thr could xst nutrons Paul n bta dcay a nutron s mttd n addton to th lctron 934 nam - nutrno cond by Frm 93 nutron dscovrd by Chadwck Nuclar and Partcl Physcs Franz Muhm

3 Nutrno Intractons Nutrnos pont-lk lptons do not ntract strongly, no colour charg charg Q = 0 no lctromagntc ntractons Only wak ntractons by couplng to W ± and Z 0 Expct vry small dtcton rats I hav don a trrbl thng. I hav postulatd a partcl that cannot b dtctd. Paul Invrs Bta Dcay ν n p ν p n Cross scton σ 44 Eν ( ν p n ) 5 0 cm MV Man Fr Path 60 lght yars of watr for MV ant-nutrno λ = 6 0 nσ 9 cm 60 lght yars n = Z N A = ν n 0 ntracts whn crossng th arth Rqur hug rats as nutrno sourcs A 3 cm -3 Nuclar and Partcl Physcs Franz Muhm 3

4 Dscovry of Nutrnos Elctron Nutrno ν dscovrd 956 by Ant-nutrno sourc Rns and Cowan Nuclar ractor --- ant-ν flux s - Targt and Dtctor l lqud scntllator Watr and Cadmum Chlord Dtcton of ant-nutrno annhlats wth atomc - ν n Cd racton dlayd by 0 s p n ncd Cd Dlayd concdncs only producd by sgnal Muon Nutrno ν 96 at Brookhavn by Pon bam Ldrmann, Stnbrgr, Schwartz Iron absorbr --- only muons survv π - bam obsrv π ν ν n don't s ν n p p ν ν and ν ar dffrnt Tau Nutrno ν τ 000 at Frmlab - Donut p on tungstn targt produc D s msons D s τ τ τ ν ν N τ X τ ν ν τ γ Cd Nuclar and Partcl Physcs Franz Muhm 4 π ν p n ν p n γγ *

5 Nutrno Physcs Nutrno Sourcs Natural radoactvty.g. rocks Cosmc rays httng th atmosphr Nuclar ractors Partcl acclrators Sun - nuclar fuson ractor 4 p 4 H ν 6.7 MV Flux on arth ~0 cm - s - 00 bllons/sc through your fngr nal Nutrno Mass No apparnt rason for nutrno to b masslss all othr frmons hav mass Drct mass masurmnts Bta dcay nrgy spctrum dγ GF = 3 de π dγ de E ( E E ) 0 E 0 E E Kur plot lnar H H Endpont modfd by rsoluton and non-zro ν mass Trtum Bta Dcay Mass m(ν ) < 3 V Nutrno Oscllatons No apparnt rason for nutrnos not to oscllat nto ach othr 3 3 ν Nuclar and Partcl Physcs Franz Muhm 5

6 Nutrno Oscllatons Lpton flavour consrvaton L, L, L τ ar consrvd sparatly Nutrnos wth mass can mx wak gnstats ar lnar suprpostons of mass gnstats L, L, L τ not absolutly consrvd L, L, L τ Volaton too small to obsrv BF < 0-40 Nutrno flavours Easy to undrstand, can b xpandd to 3 gnratons ν cosθ snθ ν = ν snθ cosθ ν Tm voluton ν ( t) = ν (0)xp E t ( ) ( t) ν ( t) = ν (0)xp E Intnsty I(t) for ntal ν bam I Nutrno nrgy E and mass dffrnc m E ν = p E m p m p Nutrno Oscllaton Probablts P P E >> m ( ) ( E E ) cos θ sn θ 4sn θ cos θ sn ( t) = Iν (0) ( v v ) = sn t θ sn m Dstanc from sourc L [m], E[MV] and m [V ] Nuclar and Partcl Physcs Franz Muhm 6 m.7 m ( ) [V] L[m] v = sn sn v θ E[MV] m E E.7 m [V] L[m] E[MV] E m / E

7 Solar Nutrnos Standard Solar Modl (SSM) Bahcall Prdcts rats and solar nutrno nrgy spctra pp flux blow 0.4 MV 8 B ν up to 4 MV pp cycl Homstak Exprmnt Frst obsrvd solar nutrnos n 970s 00,000 gallons of Davs clanng flud C Cl 4 Masurmnt ν 37 Cl 37 Ar 0.5 Ar atoms/day.56±0.3 SNU SSM prdcton.5 Ar atoms/day 7.7±.3 SNU Puzzl - What s wrong? Exprmnt, SSM, Nutrnos SNU = ntracton 0 36 targt atoms/sc Nuclar and Partcl Physcs Franz Muhm 7

8 Solar Nutrnos II Supr-Kamokand 50,000 tons of watr,,000 phototubs undrground nsd a mn n Japan, startd 997 ν Dtcton Elastc scattrng ν ν Drctonal snstvty Masurmnts (0.465 ± ) x SSM ν dfntly from sun Sgnal from cntr of sun Puzzl - What s wrong? Homstak xprmnt confrmd Exprmnt, SSM, Nutrnos Nuclar and Partcl Physcs Franz Muhm 8

9 Solar Nutrnos III SNO --- Sudbury Nutrno Obsrvatory 000 tons of havy watr (D O) 0,000 photo multplrs tubs Snstvty SNO s abl to masur ν but also ν and ν τ (ν =,,τ ) Chargd Elastc Nutral currnt (CC) scattrng (ES) currnt (NC) ν D ν ν D n p ν - Chargd Currnt - Nutral Currnt p p ν Masurmnts 003 rsults 3% of SSM 00% of SSM 3 % of solar ν s arrv as ν at arth 00% of solar ν s dtctd f ν and ν τ ar ncludd Puzzl - What s wrong? Exprmnt, SSM, Nutrnos Nutrno Oscllatons ν chang to ν n flght Nuclar and Partcl Physcs Franz Muhm 9

10 Atmosphrc Nutrnos Cosmc Rays Protons ht nucl n uppr part of atmosphr Producng chan of partcls copous sourc of nutrnos Man dcay squnc π ν and π ν ν ν ν ν Expct ν for ach ν ~990 st ndcatons for too fw ν Supr-Kamokand Can dscrmnat ν from ν N X ν N ν Rcol muon producs clan rng Rcol - producs fuzzy rng X ν N X ν N X Nuclar and Partcl Physcs Franz Muhm 0

11 Atmosphrc Nutrnos II Masurmnts 998 Supr-Kamokand Obsrv sgnfcant dfct of ν and agrmnt for ν Nutrno Dsapparanc ν travrsng th arth. arrvng at th dtctor from blow dsappar Nutrno Oscllatons Atmosphrc nutrnos ν chang to ν τ n flght Frst Evdnc for Nutrno Oscllatons Nuclar and Partcl Physcs Franz Muhm

12 Dscovry of Nutrno Mass Atmosphrc Nutrno Oscllatons Atmosphrc ν chang nto ν τ Oscllaton P v vτ = sn probablty Ft data for bst valus of mass dffrnc m 3 and mxng angl θ τ Fnd θ τ 45 0 and m V Nutrnos hav Mass Solar Nutrno Oscllatons Supr-Kamokand, SNO Kamland ractor ant-ν Fnd θ 33 0 and Nutrno mass m V Mnmum m ν ~ 0.05 V scnaros Cosmology Bg Bang larg nr. of nutrnos Nutrnos ar hot dark mattr canddats Suprnova 987A Kamokand and IMB Obsrvd ~ 0 nutrnos.7 m [V] L[m] ( ) ( ) τ sn θ τ E[MV] Nuclar and Partcl Physcs Franz Muhm