Mass measurements for fundamental subatomic physics · Mass measurements for fundamental subatomic...

Mass measurements for fundamental subatomicphysics

Tommi Eronen

University of Jyvaskyla, Department of Physics

April 12, 2010

Mass measurements for fundamental subatomic physics Tommi Eronen

Outline

• Method, JYFLTRAP

• Decay energies from atomic masses for. . .• superallowed β emitters (+ mirror decays for SM testing)• neutrino physics• 115In — ultralow β decay Q value


JYFLTRAP at IGISOL

IGISOL

• Served by JYFL K130 cyclotron; variety of beams available

• Stopping reaction products in gas

• Fast (≈ ms) and universal — all elements available

Production of ions

• Fusion• light-ion induced, 26Mg(p,n)26Al,26Alm

• fusion evaporation, 54Fe(32S,3p1n)80Y

• Fission — light-ion induced (140Te, 135Sn, 131In, 122Pd)

• Offline — Electric discharge source ( ie. 76Ge, 76Se)


Schematic view


Measurement principle

In these studies we measure cyclotron sideband frequency

ν+′ + ν−′ = νc ′ ∼=1

2π

q

mB (1)

Decay energy Q from masses

Q = Mparent −Mdaughter =

(νc,daughter

νc,parent− 1

)mdaughter (2)

Q Precision on the order few ×10−9

• mass doublets

• invariance theorem [G. Gabrielse, Phys. Rev. Lett. 102, 172501 (2009)]


Prepare a clean sample – purification trap[G. Savard et al., Phys. Lett. A 158, 247 (1991)]

• Mass resolving power R = M/∆M ≈ 105

Coun

ts /

a.u. 26Alm 26Al(gs)

(Purification trap frequency - 4,135,000) / Hz

100

101

102

0 50 100 150

≈ 40 Hz

26Mg

750 800 850


Prepare a clean sample – purification trap??C

ount

s / a

.u.

54Com + 54Co(gs)

(Purification trap frequency - 1,992,000) / Hz

100

101

102

103

-200 -150 -100 150 200 250

54Fe


High-resolution cleaning

Reaching R = 106 or more

0

100

200

-15 -10 -5 0 5 10 15 20 25

# / A

rb. u

nits

Dipole frequency - 1991810 / Hz 54Fe

0

10

20

30

-15 -10 -5 0 5 10 15 20 25

# / A

rb. u

nits

Dipole frequency - 1991480 / Hz 54Co, 54Com

• Time needed: ≈ 200 ms

• Here 7 Hz separation


Frequency determination

• TOF-ICR• [G. Graff et al., Z. Phys. A 297, 35 (1980)]• [M. Konig et al., IJMS 95, 142 (1996)]

• Ramsey method [N.F. Ramsey, RMP 62, 541 (1990)] [S. George et al., PRL 98, 162501

(2007)]M

ean

time

of fl

ight

/ µs

νRF - 1,991,680.6 (Hz)

’co54_4_0_2d.dat’ u ($1-reso):2:3

150

180

210

240

-15 -10 -5 0 5 10 15

54Co+

T1/2 = 193.27 ms


Superallowed β decays

• nuclear 0+ β+

−−→ 0+ decays

• isospin T = 1

• pure Fermi transitions

• characterized with an ft value• f statistical rate function, ∝ Q5

EC

• t partial half-lifet1/2

b


QEC values of superallowed β emitters

0

5

10

15

20

25

30

35

0 5 10 15 20 25 30 35

Z

N

ISOLTRAP (CERN): 22Mg, 34Ar, 38Ca, 74RbLEBIT (MSU): 38Ca, 66AsCanadian PT (Argonne): 22Mg, 46V

JYFLTRAPto be publishedproposed

10C

14O

34Cl

38Km

22Mg

34Ar

38Ca

66As

70Br

74Rb

other trap measurements

26Si

30S

42Ti46V

50Mn

54Co

62Ga

26Alm

42Sc


QEC values of superallowed β emittersBefore Penning traps measurements with reactions• (p,n) threshold• (3He,t)• (p, γ) + (n, γ)• Best results ≈ 100 eV

Penning trap measurements• Still to do: 10C, 14O, 70Br• To verify old, still quite precise measurements

QEC (keV)

34Clabcde

5489 5490 5491 5492 5493 5494

QEC (keV)

38mKa

b

c

d

6043 6044 6045 6046

JYFLTRAP

JYFLTRAP


Comparison to old

-3.00

-2.00

-1.00

0.00

1.00

14O 54Co50Mn46V42Sc34Cl26 mAlIS

OLTR

AP

Canadian PT

Münich3He,t

RED: JYFLTRAP

Dif

fere

nce

from

ave

rage

(ke

V)

Parent nucleus


corrected ft → Ft

Conserved vector current (CVC) hypothesis:

Ft = ft(1 + δ′R

)(1 + δNS − δC ) =

K

2G 2V

(1 + ∆R

V

)• ft — experimental, precision 0.1%

Corrections — 1%: (10% precision needed)

• δC — isospin-symmetry-breaking

• δ′R — NS independent radiative

• δNS — NS dependent radiative

• ∆RV — transition-independent radiative


Ft values[J.C. Hardy and I.S. Towner, Phys. Rev. C 79, 055502 (2009)]

Blue: QEC from JYFLTRAP + 26Al ISOLTRAP, 46V Canadian PT


Vud of the CKM matrix

Vud Vus Vub

Vcd Vcs Vcb

Vtd Vts Vtb

|d〉|s〉|b〉

=

|d ′〉|s ′〉|b′〉

• quark-mass eigenstates |x〉 to weak eigenstates |x ′〉

Vector coupling constant GV

GV = GFVud,

where GF = 1.16637(1)× 10−5 GeV−2.

Vud =K

2G 2F

(1 + ∆V

R

)Ft


Vud from different sources

Vud (0.97xx)

superallowed 2005superallowed 2008

neutronpion

mirror

0 10 20 30 40 50 60

• from superallowed — most precise

• newcomer: mirror decays [Naviliat-Cuncic and Severijns, PRL 102, 142302 (2009)]


CKM matrix unitarity

• top-row unitarity requirement: |Vud|2 + |Vus|2 + |Vub|2 = 1

• |Vud|2 from superallowed β decays

• |Vus|2 from Kaon decay

• |Vub|2 negligible

Vud2 ( 0.9XX )

Hardy1990

Hardy2005

Hardy2008

47 48 49 50 51

Vus2 ( 0.0XX )

48 49 50 51 52

SUM - 1 ( 10-3 )

-5 -4 -3 -2 -1 0 1


Superallowed β decay summary

• Penning trap QEC value measurements cover all but 10C, 14O

• ft precision limited in most cases by branching ratio

• Curiosity: in 62Ga ft limited by Q value

Deviation from Hardy2005 (keV)

14OButler (1961)

Barden (1962)Roush (1970)

Vonach (1977)White (1977)Tolich (2003)

-3.0 -2.0 -1.0 0.0 1.0 2.0


Q value measurements for neutrino studies

Neutrinos usually associated with normal β decay:

(A,Z )→ (A,Z + 1) + e− + νe (3)

(A,Z )→ (A,Z − 1) + e+ + νe (4)

But also from double beta decay:

• 2νββ

• extremely weak process, T1/2 > 1020 y


Q value measurements for neutrino studies

Double β decay is a 2nd order process

Some cases (β−β−):

• 48Ca → 48Ti

• 76Ge → 76Se

• 100Mo → 100Ru

• 124Sn → 124Te

• 136Xe → 136Ba

• 150Nd → 150Sm


Two varieties of double β decay

• Two-neutrino mode (2νββ)

• Zero-neutrino mode (0νββ)• Only if mν 6= 0• and ν = ν→ neutrino is a Majorana particle→ conservation of lepton number breaks


Two varieties of double β decay

Detection of 0νββ

• 2νββ makes huge background

• decay branch to 0νββ is very small

• One claim: Heidelberg-Moscow 76Ge →76Se


Motivation for accurate Q value

• Need the Q value to be wellbelow detector resolution

• For phase space calculation

• Example: 100Mo

[S. Rahaman et al., PLB 662, 111 (2008)]

3035(6) keV – AME20033034.40(17) keV – New


Recent Penning trap measurements

Multiple “hits”:

76Ge

• SMILETRAP (Douysset2001) 2039.006(50) keV

• JYFLTRAP (Rahaman2008) 2039.04(16) keV

• FSU (Mount2010) 2039.061(7) keV130Te

• FSU (Redshaw2009) 2527.518(13) keV

• Canadian PT (Scielzo2009) 2527.01(32) keV


Double electron capture

Not yet experimentally observed

• A(Z ,N) + 2e− → A(Z − 2,N) + 2ν

• A(Z ,N) + 2e− → A(Z − 2,N)

• Half lives very long

Accurate Q value is important

• for searching resonant decay

• if found, can reduce half-life by 10n, n > 6

• feasibility of huge-scale experiments

Decay rate1

τ1/2=

(∆M)2

(Q − E )2 + 14 Γ2

Γ (5)


74Se

From [B.J. Mount et al., Phys. Rev. C 81, 032501(R) (2010)];

• here gs-to-gs Q value form AME2003

• Atomic electon binding energies (KK, LL, KL)


74Se

New precise Q values published recently

• JYFLTRAP by V. S. Kolhinen et al., Phys. Lett. B 684, 17(2010)

• at FSU by B. J. Mount et al., Phys. Rev. C 81, 032501(R)(2010)

Deviation from JYFLTRAP (keV)

74Se

E*

Kolhinen2010Mount2010

AME2003

1205.0 1206.0 1207.0 1208.0

Half life estimate T1/2 ≈ 5×1043

〈mν〉2 years (mν in eV)


112Sn → 112Cd

at JYFLTRAP by S. Rahaman et al., Phys. Rev. Lett. 103,042501 (2009)

• Similar to the 74Se case

• Resonance ∼ inside AME2003 errorbars

• AME2003 Q = 1919(4) keV, now 1919.82(16) keV

Now confirmed to be off by -4.5(3) keV (KK capture)

Half life estimate T1/2 >5.9×1029

〈mν〉2 years (mν in eV)

→ Scale for decay detection experiment would be huge


Recent Penning trap measurements (2νECEC )

Multiple “hits”:

74Se

• JYFLTRAP (Kolhinen2010) 1209.169(49) keV

• FSU (Mount2010) 1209.240(7) keV

Others:

• 136Xe FSU (Redshaw2007) 2457.83(37) keV

• 120Te Canadian PT (Scielzo2009) 1714.8(13) keV


Summary 2ECEC

• This decay mode has not been observed yet (T1/2 > 1023 y)

• Resonant decays• reduces T1/2 by several orders of magnitude• high precision Q values needed• Feasibility for huge-scale experiments

• Lots of Q values still to be improved

• Overlapping trap experiments (example 74Se)

• Also need for spectroscopy — end state Jπ


Ultralow β− decay Q value of 115InUltra-high precision Q value• Mount et al., PRL 103, 122502 (2009): 155(24) eV

High precision Q value + branching ratio + NME• Wieslander et al., PRL 103, 122501 (2009)

• Q value 350(170) eV• Partial T1/2 = 4.1(6)× 1020 y


Ultralow β− decay Q value of 115In

Mount 2009 FSU Q-value

Theoretical

Wieslander 2009 JYFLTRAP+HADES

• 4th forbidden unique decay

• Estimate electron screening?

• Experiments set strict boundaries for theory


JYFLTRAP Collaboration

JYFLTRAP JYFL theory CollaboratorsT. Eronen J. Suhonen J.C. HardyV.S. Kolhinen M.T. MustonenJ. HakalaA. JokinenA. KankainenJ. Rissanen

J. Aysto+ IGISOL

past trappersS. RahamanC. WeberV.-V. ElomaaU. Hager


Thank you for your attention!See also posters:

• V.S. Kolhinen: Poster #17:

Accurate Q value for the 74Se double-electron-capture decay

• B. Mount: Poster #7:

High-Precision Atomic Mass Spectrometry with Applicationsto Fundamental Constants, Neutrino Physics, and PhysicalChemistry


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