1 S1242 High Precision Mass Measurements of Superallowed T=2 Nuclear Beta Decay Emitters.
Transcript of 1 S1242 High Precision Mass Measurements of Superallowed T=2 Nuclear Beta Decay Emitters.
TRIUMF
ISAC
1
S1242S1242
High Precision Mass High Precision Mass Measurements of Superallowed T=2 Measurements of Superallowed T=2
Nuclear Beta Decay EmittersNuclear Beta Decay Emitters
TRIUMF
ISAC
2
Quarks in the SM
Coupling to Higgs field ΦT=(Φ1 Φ2):
after symmetry breaking: mass term weak ≠ mass eigenstates:
interaction Lagrangian quarks - W+ and W-
chuLGdLG RjiuijRji
dij . Yukawa
coupling
LLL dDd '
RRR dDd 'LLL uUu '
RRR uUu '
WdDUugchWdug LiLLLiLiLi ''..
__
tbtstd
cbcscd
ubusud
LL
VVV
VVV
VVV
DUVCabibbo–Kobayashi–Maskawa matrix: - decay
TRIUMF
ISAC
3
Vud measurements
J. Hardy, CIPANP 2009
superallowed 0+→ 0+ decays most precise way to extract Vud
due to J = T = L = S = 0:• pure Fermi decay (only vector part)• transition between isobaric analog states• only total Isospin Ladder Operator T± alters wave-function for T = 1:
2
22
2
22 2)(
g
GFM
g
GM VV
TRIUMF
ISAC
4
ft- values, corrected Ft-value and Vud
Combination to ft-values (T=1):
corrected Ft value:
V
R … transition indep.R and NS ….transition dep.
c … isospin symmetry breaking (tans. dep.)
Corrections: small ( about a few %), BUT dominating uncertainty
const2 2
VG
Kft f … phase space integral (dep. on Q-
value)
t … „partial halflife“ (dep on. BR and T½ )
K … numerical constant const
)1(2)1)(1(
2
VRV
CNSR G
KftFt
F
Vud G
GV
Experimental Input
}radiative corrections
TRIUMF
ISAC
5
Tests of Fundamental Symmetries I
J. Hardy & I.S. TownerJ. Hardy & I.S. Towner W. J. Marciano et al.
1) CVC 2) Scalar Currents
3) |Vud |2
/= 0.28J. Hardy & I.S. Towner, Phys. Rev. C 79, 055502 (2009)
)13(0011.0V
s
c
c
TRIUMF
ISAC
6
5) Coupling Universality:
GF (|Vud|2 + |Vus|2 + |Vub|2 ) = G = G
e.g. Z boson in SO(10)
implies: M(Z)> 750 GeV at 95% CL
Tests of Fundamental Symmetries II
4) CKM: basis transformation weak ↔ mass eigenstates
Unitarity test of 1st row:
|Vud|2 + |Vus|2 + |Vub|2 = 1 SM= 0.99995(61) Experiment
J. Hardy & I.S. Towner, Phys. Rev. C 79, 055502 (2009)0.9491(4) 0.0508(4)
B. Tschirhart , CIPANP 2009
TRIUMF
ISAC
7
T&H’s c: use W+-spin, not isospin +
new c – calculations (including core orbitals)I.S. Towner & J. C. Hardy, Phys. Rev. C77, 025501 (2008)
Developments for cJ.C. Hardy and I.S. Towner, Phys. Rev. C66, 035501 (2002 )
Phys. Rev. C71, 055501 (2005)W. E. Ormond and B. A. Brown, Phys. Rev. C52, 2455 (1995)
Nucl. Phys. A 440, 274 (1985)
G.A. Miller & A. Schwenk, Phys. Rev. C 78, 035501 (2008)
N. Auerbach, Phys. Rev. C 79, 035502 (2009)
J. C. Hardy & I.S. Towner, Phys. Rev. C 79, 055502 (2009)
New approach to c (Coulomb force treated by perturbation theory)
results lower than T&H
New Hartree-Fock (same model space as Woods-Saxon with core orbitals)
H. Liang et al., Phys. Rev. C, 064316 (2009)
c accessed via self-consistent RPA in relativistic framework
/= 1.0-1.1
implementedimplemented
differentlydifferently
TRIUMF
ISAC
8
c : comparisons between models
T&H (2005) ↔ O&B
T&H (2008) ↔ Perturbation theory T&H (2008) ↔ RPA
T&H: WS (2008) ↔ HF (2009)
TRIUMF
ISAC
9
Status of c
• T&H: currently best calculations– Wood Saxon & Hartree-Fock – same model space– good agreement with each other and
CVC
• 4 other descriptions– 3 with numerical results
– disagree with T&H (all lower c )
– but all need improvements
benchmark models / check c – assume CVC– use
– compare with experiment
– new cases or/and cases with large c
Tz= - 1
Tz= 0
|Vud|2
}
NScR
Ftft
11
superallowed T=2 superallowed T=2 casescases
TRIUMF
ISAC
10
• new system → wider range for tests of c
• T=2 allows systematic check of c
• c expected to be larger:
roc
cmcc
example: 32Ar → 32Clcalculation based on HF (B.A. Brown) c
cm = 0.6 %
cro = 1.4 %
configuration mixing
with other 0+
radial overlap• radial wavefn altered by Coulomb• enhanced near proton drip lineT=1
T=2
Superallowed T=2 Decays
M. Bhattacharya et al.,Phys. Rev. C 77, 065503 (2008)
TRIUMF
ISAC
11
Exp. Challenges for T = 2
• short half-lives ( down to 40 ms ) challenge for high precision mass measurements
• -delayed proton emission
M. Bhattacharya et al.,Phys. Rev. C 77, 065503 (2008)
→ feasible with HCI at TITAN
→ feasible: 32Ar
BR=22.71(11)(11)
ft (32Ar)=1552(12)
c (exp)= 2.1 ± 0.8 %
c (th. )= 2.0 ± 0.4 %
Note: used m.e.(31S) + their Sp measurement:
m.e.(32Cl)=-13337.0 ± 1.6 keV
TRIUMF
ISAC
12
Proposed MeasurementsIsoto
peHalf-life
Present m
[keV]
m TITAN (A+) [keV] q
TITAN HCIm [keV]
E*[keV
]
comment
Mg-20
90 ms27 1.865 10
He-like 0.186
request stage 2
Na-20
448 ms6.66 1.864 9
He-like 0.207
13 request stage 2
Si-24 140 ms 19.47 2.237 12 He-like 0.186 ?
Al-24 2.053 s 2.78 2.236 11 He-like 0.203 6 proposal S1191
S-28125 ms 160 2.609 14 He-like 0.186
requires development
P-28270 ms 3.32 2.607 13 He-like 0.201 21
requires development
Ar-32 98 ms1.8 2.981 16 He-like 0.186
requires development
Cl-32 298 ms6.59 2.979 15 He-like 0.199
0.4 requires development
Ca-36
102 ms40 3.353 10
Ne-like 0.335
feasible, request stage 2
K-36 342 ms0.39 3.352 9
Ne-like 0.372 8
request stage 2
Ti-4053 ms 160 3.725 12 Ne-like 0.310
requires development
Sc-40182 ms 2.83 3.724 11 Ne-like 0.339
8 requires development
Cr-44 53 ms 50 4.097 14 Ne-like 0.293requires
development
V-44 111 ms 121 4.096 13 Ne-like 0.315 ? ?
Ti-43 509 ms 6.90 4.002 12 Ne-like 0.334requires
development
Fe-48 44 ms 70 4.469 16 Ne-like 0.279requires
development
Mn-48 158 ms 112 4.468 15 Ne-like 0.298
0.9 requires development
Ni-52 38 ms 84 4.842 18 Ne-like 0.269requires
development
Co-52 115 ms 65 4.840 17 Ne-like 0.28530 requires
development
Isotope Target Source Yield [ions / sec]
Mg-20 SiC TRILIS 240
Na-20 SiC Re surface 1.7▪108
Isotope Target Source Yield [ions / sec]
Ca-36 TiC TRILIS feasible (M. Dombsky)
K-36 TiC Re surface 2.9▪105
Request for each pair:1 shift setup + calibration5 shifts measurement
TRIUMF
ISAC
13
Impact of Measurements
• BR measurements are planned
• require >10 ions/sec
contributions to uncertainty of ft-value:
TRIUMF
ISAC
14
Test of IMME Quintets
C. Yazidjian et al., Phys. Rev. C 76, 024308 (2007)A. Gade et al., 76, 024317 (2007)
A = 20 A = 36
20Mg
M.E. [keV]
E* [keV]
0+ 17570(27)
2+ 19168(29) 1598(10)
Check for cubic term:
TRIUMF
ISAC
15
Summary• Vud most precisely determined via superallowed 0+→ 0+ nuclear
decays• CKM unitarity test: σud ≈ σus
• isospin symmetry breaking corrections c
– current calculations (T&H) in great agreement with CVC– many new theoretical descriptions (in development)– systematic discrepancies between models– experimental data to benchmark models (extreme cases i.p.
T=2)• T=2 cases in experimental reach: NEW NUCLEONIC SYSTEM
– BR measurements feasible (32Ar done + other in preparation)– masses: HCI on short lived isotopes with TITAN
propose high precision mass measurements on superallowed emitters:
20Mg, 24Si, 28S, 32Ar, 36Ca, 40Ti, 44Cr, 48Fe, and 52Nirequest 1 shift setup + 5 shifts measurement for each case
measurements also important for tests of IMME (i.p. 20Mg, 36Ca)
TRIUMF
ISAC
16
S1242 collaborationTRIUMF: M. Brodeur, T. Brunner, S. Ettenauer, A. Gallant, A. Lapierre, S.
Triambak, P.P.J. Delheij, J. Dilling
University of Washington: A. Garcia, C. Wrede
Texas A&M University: D.G. Melconian
University of Manitoba: G. Gwinner
NSCL: R. Ringle
TITAN collaboration
TRIUMF
ISAC
17
Details on new Details on new c c descriptionsdescriptions
TRIUMF
ISAC
18
isospin operator +c
T&H: W-spin operator
M&S: • W-spin formalism loses SM isospin commutation relations• radial quantum numbers not necessarily the same• separation model dependent• correct SM +
• complete formalism developed to calculate c
aar ,
,
ba
• because proton and neutron states are not the same
• but assumes radial quantum numbers are the same
roc
cmcc
G.A. Miller & A. Schwenk, Phys. Rev. C 78, 035501 (2008)
TRIUMF
ISAC
19
Wood-Saxon ↔ Hartree Fock
nucleus with Z+1 protonsCoulomb term in proton wavefunction:• Wood Saxon:
• Hartree Fock:
J. C. Hardy & I.S. Towner, Phys. Rev. C 79, 055502 (2009)
r
ZeRrV CC
2
)(
r
eZr
rr
erdrV rdir
C
2
11
2
13 )1(
)()(
3/1
113
2
)(3
2
3)(
rrd
erV ex
C
difficult to calculateexactly in Skyrme HF
T&H: 1) calculate single HF for A-1 nucleus →
2) use proton mean field for proton wf →
3) use neutron mean field for neutron wf →
in agreement with T&H’s Wood-Saxon
e.g.:33S34Cl34S
different than O&B
TRIUMF
ISAC
20
new calculations c
self consistent RPA build on• relativistic Hartree with
– DD-ME1 , DD-ME2 – NL3 , TM1
• relativistic Hartree-Fock with – PKO1 , PKO2 , PKO3 – PKO1 but Coulomb
exchange term turned off
Conclusions:Conclusions:1) RHF+RPA (without C-Ex) = RH+RPA
proper treatment of Coulomb field is essential for c
2) more investigations required (e.g. proper n-p mass difference, isoscaler and isovector pairing, deformation)
H. Liang et al., Phys. Rev. C, 064316 (2009)
TRIUMF
ISAC
21
new calculations c II
Perturbation Theory:
• charge independent Hamiltonian H0
• treat Coulomb force perturbatively
details:
• VC: uniformly charged sphere
• off diagonal matrix elements
largest elements for giant isovector monopole states (IVMS)
• wave function for PT: gs (H0) + IVMS
N. Auerbach, Phys. Rev. C 79, 035502 (2009)
213/2
1
418
A
Vc
nitrR
ZenV
izic )(0
20 2
3
2
z-comp. of isovector monopole operator
isospin impurity
num. factor (model dep.)
symm. potential strength
Model characteristics:• includes collectivity• pure isospin formulation• BUT: equivalent to W-spin • uncertainties in model parameters• neglects non-Coulomb charge dep. int.