Searching for chirality flipping interactions in nuclear beta decay. Presentation to REU Students July 2015

Transcription

1 Sarching for chirality flipping intractions in nuclar bta dcay Prsntation to REU Studnts July 015

2 Wak intractions in nucli: a prob to sarch for nw physics Aljandro Garcia Univrsity of Washington Whil th LH sarchs at th nrgy frontir. Prcision xprimnts in nuclar bta dcays can b mor snsitiv in som spcific aras Studnts David Zumwalt and Andy Palmr look at th dvic thy built to produc 6H at UW

3 Hlicity H p p J J For a spin ½ particl hlicity can b Right or Lft Rmarkabl: nutrinos mittd in bta dcay ar Lft-handd 3

4 Hlicity H p p J J For a spin ½ particl can b Right or Lft Rmarkabl: nutrinos mittd in bta dcay ar Lft-handd Problm: hlicity is not a rlativistic invariant. (hink about an obsrvr moving fastr than th particl: p flips dirction but J dosn t) Solution: chirality. orrct dfinition dals with rlativistic quantum mchanics and I will avoid it today. wo important conclusions to rmmbr: m=0 particls (.g. photons) chirality == H. m 0 particls with wll-dfind chirality can b thought off as linar combinations of both hlicitis with amplituds / and / 4

5 Hlicitis and nuclar bta dcays: Parity Violation (58 yars!) P r r P p p P( r p) ( r p) P invrts coordinats and momnta, but not angular momnta If P wr consrvd lctrons should com out isotropically from polarizd 60 o. Elctrons com mostly opposit th polarization of 60 o. 5

6 Hlicitis and nuclar bta dcays: Parity Violation What maks lctrons com out prfrntially opposit th polarization? 1) onsrvation of Ang. Mom.: and spins hav to align along th dirction of initial polarization. ) s ar lft handd (momntum prfrntially opposit spin). Probabilitis work just as for idal Strn-Grlach dvic i cos( / ) sin( / ) Probabilitis of obsrving at angl sin 6

7 6H bta dcay: - corrlation aking th dirction as axis of quantization: So, for 6H: 7

8 h modrn contxt. h Standard Modl and som opn qustions. What is th mchanism for th mass of nutrinos? (hints that it dosn t work lik th othrs) an thr b right-handd nutrinos from nuclar bta dcays? Why ar th numbr of gnrations for quarks idntical to thos of lptons? Answrs should illuminat nw physics 8

9 Sarchs for Scalar and nsor currnts. Ar wak dcays carrid only by W s? + W d u + Or is thr somthing nw?? u d + Lpto-Quark u d + L R R L i f L L A i f H ) ( ) ( ' ' 5 5 E m b E p E p a dw dw 1 0 Dcay rat: / / 1 / / ' ' A A A A a A b '

10 Sarchs for Scalar and nsor currnts. Ar wak dcays carrid only by W s? + W d u + Or is thr somthing nw?? u d + Lpto-Quark u d + L R R L i f L L A i f H ) ( ) ( ' ' 5 5 E m b E p E p a dw dw 1 0 Dcay rat: ' ' A A a A b ' Standard modl nsor currnts

11 Prcision bta dcay vrsus pion dcays and LH : F. Wautrs, A. García, and R. Hong Phys. Rv. 89, (014). an prcision compt with nrgy? Ys.

12 6H littl-a collaboration P. Mullr, A. Lrdd Argonn National Lab X. Fléchard, E. Linnard, LP, AEN, Franc O. Naviliat-uncic NSL, Michigan Stat Univrsity Y. Bagdasarova, A. Garcia, R. Hong, M. Strnbrg, D. Storm, H.E. Swanson, F. Wautrs, D. Zumwalt Univrsity of Washington, Simpl dcay (~100% to ground stat) Pur Gamow-llr dcay Half-lif appropriat for trapping (~1 sc) Larg Q-valu, good for sing ffcts of Nobl gas no worris about chmistry Simpl nuclar structur Li H

13 Sarching for tnsor currnts in 6H H Li Instad of dtcting th nutrino, dtrmin momntum of lctron and 6Li. Problm: slow 6Li, will loos momntum in ANY supporting layr. Solution: hold 6H with light. 13

14 Magnto Optical rap Six orthogonal, countr propagating bams of opposit circular polarization ar rd dtund as in th Dopplr cooling configuration Anti Hlmholtz coils introduc a quadrupol fild with zro magntic fild at th cntr and linarly incrasing fild in th dirctions of th lasrs 14

15 rapping of 6 H RF discharg in xnon/krypton to xcit into mtastabl stat ycling on 1083 nm transition to transvrsly cool, slow down and trap magnto optically rappd atoms transfrrd to dtction chambr with nd MO Basd on xprinc from 6 H, 8 H charg radius masurmnts by ANL collaborators: L. B. Wang t al., PRL 93, (004) P. Mullr t al., PRL 99, 5501 (007)

16 On of th lasr tabls:

17 6 H Littl a, dtction Elctron and 6 Li rcoil nuclus dtctd in coincidnc E E scintillator systm for lctron dtction (nrgy, start of tim of flight) Micro channl plat dtctor for dtction of rcoil nuclus (position, tim of flight) 17

18 Ebta vrsus OF simulations Standard Modl nsor currnts

19 Elctric fild of apprx kv/cm to guid 6Li ions. 19

20 E E scintillator systm for lctron dtction (nrgy, start of tim of flight) Micro channl plat dtctor for dtction of 6 Li rcoil nuclus (position, tim offlight)

21 MP (micro chanl plats with dlay lin anods) MPs (micro channl plats) Dlay lin anods x tx1 X = c (tx1-tx) tx 5 polarization voltags: front MP, back MP, dt. fram, anod_rf, anod_sig 5 signals: charg mittd by MPs, charg collctd on anods (x1,x,y1,y) 1

22 X&Y calibration: - Rconstruction with 1 st and d ordr polynomial functions up to 0.6 mm dviation on th dgs of MPs Pol Pol1, ffct nhancd by x h_rs_pol1_mm h_rs_pol1_mm Entris 5 Man RMS Pol 30 0 Pol, ffct nhancd by x h_rs_pol_mm h_rs_pol_mm Entris 5 Man RMS

23 Show Pnning ionization animation

24 6H littl a outlook Routinly trap 100 6H atoms. Prsntly working towards longr stability for a 1 wk long xprimnt. Dtction systms working. First data run plannd for latr in 015. Aiming for a 1% dtrmination of littl a by nd of 015. R&D for spctrum shap dtrmination (Savanna s talk). Dtction trap aptur trap

25 Backup slids

26 Hlicitis in th Standard Modl H p. J p J max Exampl: photons hav H =±1. h lctro-wak intractions ar mdiatd by VEOR (Spin=1) particls (Photon, Z0, Ws) Or quivalntly (notic anti nu): A consqunc is that th intractions don t flip hlicitis. All th particls that coupl to th Wak intractions ar lft handd; Particls Lft handd Anti particls Right handd

27 Hlicitis in th Standard Modl onsqunc: -antinu corrlation If th nuclar spins don t flip thn th lptons hav total Jz=0 E p E p d d 1 onsqunc: -antinu corrlation If th nuclar spins flip thn th lptons hav total Jz=1 E p E p d d 1

28 Hlicitis in with Scalar or nsor urrnts onsqunc: -antinu corrlation If th nuclar spins don t flip thn th lptons hav total Jz=0 E p E p d d 1 onsqunc: -antinu corrlation If th nuclar spins flip thn th lptons hav total Jz=1 E p E p d d 1

29 Now hav ~10 10 atoms of 6 H/s at Sattl via 7 Li(d, 3 H) 6 H Now hav a rliabl sourc of 6 H yilding ~ atoms/s in a clan room. A. Kncht t al. NIM A. 660, 43 (011) 6 H s pr sc at diffrnt labs

30 oupling constant for Wak Dcays from th liftim of 6 H

31 Extracting g A from th liftim of 6 H wo prvious xprimnts disagrd by 9 ms. Rsolvd th discrpancy. Our rsults in combination with abinitio calculations shows that qunching is at most about %. A. Kncht t al., Phys. Rv. Ltt. 108, 150 (01); Phys. Rv. 86, (01).

32 Mirror Flap Mirror Lgnd Half rflcting mirror Fibr coupling Low powr Lasr Systm OPIA Lasr λ=706 nm Faraday Isolator AOM 706 Fibr λ/ PBS λ/4 Lns No us Iris Wav Mtr D P4H discharg FP Intrfromtr OPIA Lasr λ=1083 nm Faraday Isolator AOM 1 EOM ISO o Amp. EOM 1 4 H discharg P D 1 P D 3 o Amp. Lasr λ=1083 nm

33 Lgnd High powr Lasr Systm Mirror Flap Mirror Half rflcting mirror Fibr coupling o MO1 Bam λ/ PBS λ/4 No us o Push Bam o MO Bam Lns Iris AO M 4 o Bam AO M 6 AO M 3 o Slowr Bam AO M 5 o 1 Bam From Amp.

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