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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
Mass measurements for fundamental subatomic physics Tommi Eronen
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)
Mass measurements for fundamental subatomic physics Tommi Eronen
Schematic view
Mass measurements for fundamental subatomic physics Tommi Eronen
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)]
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
Ft values[J.C. Hardy and I.S. Towner, Phys. Rev. C 79, 055502 (2009)]
Blue: QEC from JYFLTRAP + 26Al ISOLTRAP, 46V Canadian PT
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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)]
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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)
Mass measurements for fundamental subatomic physics Tommi Eronen
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)
Mass measurements for fundamental subatomic physics Tommi Eronen
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)
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen
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
Mass measurements for fundamental subatomic physics Tommi Eronen