1. Tests of fundamental weak interactions
and their symmetries
using exotic nuclei
EuNPConference
Groningen, Aug 30 – Sep 04, 2015 b+ ne
Nathal Severijns
KU Leuven, Belgium

2. Overview recent / ongoing achievements - APV and EDM e+ne
nucleus q
recent / ongoing achievements
- APV and EDM
- Vud and unitarity / Ft-values
- exotic weak currents
(scalar, tensor, V+A)
(selected experiments showing diversity in techniques used)
- new vistas and prospects for this field in the LHC era
N.S., O. Naviliat-Cuncic & M. Beck, RMP 78 (2006) 991
H. Abele, Prog Part Nucl Phys 60 (2008) 1
D. Dubbers and M.G. Schmidt, RMP 83 (2011) 1111
N.S. & O. Naviliat-Cuncic, Phys Scr T152 (2013)
F. Wauters et al., PR C 89 (2014)
S Baeßler et al., J. Phys. G: Nucl. Part. Phys. 41 (2014)
K. Vos et al., RMP (2015) to be published
see also the talk of Keri Vos

3. 1. Atomic Parity Violation & Electric Dipole Moments
probing sin2W at atomic energies (test Standard Model)
206Fr @ TRIUMF, LNL
KVI
enhancement factors of ~15 and ~50 compared to 133Cs case (Wiemann et al.)
Electric Dipole Moments
matter/anti-matter difference in the Universe
ANL and KVI
TRIUMF
Tokyo and TUM
sensitivity to EDM enhanced by (by several 100 to few 1000 times):
- near degeneracy of atomic levels
- octupole deformation of nuclear charge distribution

4. topics that will not be discussed now
- neutrino-mass determination in EC-decay of 163Ho
talk F. Schneider
- test of Lorentz violation in -decay of 20Na
talk A. Sytema
- double beta decay
talk T. Rodríguez - theory
talk R. Brugnera - GERDA experiment
talk C. Pagliarone - CUORE experiment
- parity non-conservation
posters 18 & 53

5. 2. Vud quark mixing matrix element & CKM unitarity
from
experiment
nucleus dependent
corrections
nucleus independent
|Vud| = (22)
Hardy & Towner, PR C 79 (2009)
|Vud| = (21)
Hardy & Towner, PR C 91 (2015)
= (72) s
|Vus| = (53)  (8)
Hardy & Towner , Phys. Rev. C 91 (2015)

6. O. Naviliat-Cuncic & N.S. , PRL 102 (2009) 142302
prospects - 1
superallowed Fermi transitions
- new data for 0+  0+ pure Fermi transitions
- testing isospin corrections C
- nucleus-independent radiative correction R
talk L. Xayavang
T = 1/2 mirror  transitions and neutron decay could contribute as well
N.S. , I.S. Towner et al.,
Phys. Rev. C 78(2008)
|Vud| = (17)
O. Naviliat-Cuncic & N.S. , PRL 102 (2009)

7. prospects - 2 talk C. Magron 2a. Neutron decay
no nuclear structure related corrections
issues of lifetime and asymmetry parameter first have to be resolved
(PERKEO-PERC, new lifetime measurements)
2b. T = 1/2 mirror  transitions could contribute as well
additional tests for isospin corrections C
provide additional value for Vud (set of consistent data needed)
good cases: e.g. 19Ne: β-corr. measurement performed with LPCTrap
35Ar : β-corr. measurement performed with LPCTrap;
β-asym. measurement in preparation at ISOLDE
(if A/A = 0.5%  Vud = )
- requires measurements of QEC, t1/2 and BR leading to Ft values for mirror transitions
talk C. Magron
N.S. & O. Naviliat-Cuncic, Physica Scripta T152 (2013)

8. 3. Exotic weak currents (scalar, tensor, V+A)
1.  correlation
exp.
Fierz term
!!! for pure transitions weak interaction results are independent of nuclear matrix elements !!!

9. scalar - TRINAT MOT trap at TRIUMF-ISAC – 38mK
search for scalar couplings
superallowed 0+  0+
pure Fermi transition
(t1/2 = 0.95 s)
A. Gorelov, J. Behr et al.,
Phys. Rev. Lett. 94 (2005)
TOF

10. ongoing experiments in search for scalar weak currents:
- LPCTrap-GANIL (Paul): 19Ne, 35Ar
- Jerusalem (MOT): Ne
- TamuTrap , Texas A&M (Paul): 32Ar, … (T=2, βp)
talk B. Chayon
Da/a ~ 0.3%
(analysis in progress)
35Cl charge state
distribution
from the  decay
of 35Ar
(LPCTrap - GANIL)
preliminary

11. Limits on scalar currents
Hardy & Towner , Phys. Rev. C 91 (2015)
38mK: Gorelov, Behr et al.,
PRL 94 (2005)

12. Tensor - LPCTrap @ GANIL - 6He
2006 (6He): aβν = −0.3335(73)stat(75)syst [ X. Fléchard et al., J. Phys. G 38 (2011) ]
Tensor He MOT Trap Univ. Washington, Seattle
P. Mueller, A. Garcia, et al.
- first data run in August 2013
--> 1 % measurement
% measurement by 2015
A. Knecht et al., NIM A 660 (2011) 43, Phys .Rev. C 86 (2012) & arXiv: v2 [nucl-ex]

13. Tensor - -- correlation with Paul-trapped 8Li Ions
Tensor He EIB Trap (Weizmann Inst., Univ. Jerusalem, … )
(M. Hass, G. Ron et al.)
Tensor - -- correlation with Paul-trapped 8Li Ions
aβν = − (60)stat (67)sys
G.Li, G.Savard et al., PRL 110 (2013)
data with ~20 times more statistics
+ lower systematics to be published
  1% or better

14. Tensor - β asymmetry – Leuven / ISOLDE / Prague
F. Wauters et al., NIM A 609 (2009) 156
region
analysed
Aexp (60Co) = (12)stat (16)syst
Aexp (114In) = (10)stat (10)syst
Aexp (67Cu) = (8)stat (12)syst
F. Wauters et al., Phys. Rev. C 82 (2010)
F. Wauters et al., Phys. Rev. C 80 (2009) (R)
F. Wauters et al., Phys. Rev. C 80 (2009) (R)
G. Soti et al., submitted to PR C 90 (2014)

15. Constraints on tensor type weak couplings
a(6He)
C. Johnston et al.,
PR 132 (1963) 1149
--(8Li)
G.Li, G.Savard et al.,
PRL 110 (2013)
A(60Co)
F. Wauters, N.S. et al.,
PR C 82 (2010)
A(67Cu)
G. Soti, N.S. et al., (2013) submitted
--(8Li)
A(60Co)
A(67Cu)
a(6He)

16. New vistas and prospects in the LHC era - 1
new generation of trap-based experiments
 towards 0.1% precision level
precise -spectrum shape measurements
(Leuven-Krakow, MSU-NSCL, LPC Caen, … )
bFierz : scalar / tensor weak currents
bWM : weak magnetism (Standard Model term)
- induced by strong interaction because decaying quark is
not free but bound in a nucleon;
- is to be known better when reaching sub-percent precisions
Note the different energy dependence of both effects !!

17. microcalorimeter measurements (CEA-Saclay)
recent work improving beta spectral shape at very low energies
X. Mougeot et al., PR A 86 (2012) , PR A 90 (2014)

18. miniBETA spectrometer (Leuven / Krakow)
multi-wire drift chamber
scintillator (later DSSDD)

19. double-Si spectrometer (Leuven / Krakow)
two Si p-i-n detectors
at distance of 7 mm
45Ca

20. Beta energy spectrum shape in 6He decay - NSCL/MSU
(O. Naviliat-Cuncic et al.)
Effect of weak magnetism
(Monte-Carlo simulation)
Long term goal: Measure the Fierz interference term (b) in 6He decay to search for tensor-type contributions to the weak interactions.
Current goal: measure the weak magnetism (WM) form factor in 6He decay for a tests of the strong form of CVC. The WM is the largest "hadronic SM background" in a measurement of b. 2%
Single detector
2×107 events
Principle: use a fragmented separated beam to eliminate distortions in beta spectrum due to back-scattering, out-scattering or dead-layers.
radioactive 6He source
[Run145-segs:0,1,2-Tw: ]
[Run182-segs:0,1-Ew: ]
Experiment at NSCL
range of b particles
6He decay
6He
46 MeV/A
Pile-up fraction <1.8x10-3
Collected statistics
enables extracting
the WM form factor
at ~10% relative
error.
Electron kinetic energy (chan)

21. New vistas and prospects in the LHC era - 2
- perform more measurements with polarized nuclei
access to A and other correlations involving nuclear spin
Beta and recoil asymmetries w.r.t. nuclear spin :
MOT trap : optical pumping in the trap, in magnetic holding field
TRIUMF: 80Rb, 37K
Jerusalem-Tel Aviv-Rehovot: 19Ne
ULiège-KU Leuven: 35Ar
collinear laser optical pumping
NSCL-BECOLA, ISOLDE-COLLAPS: 21Na, 23Mg, 35Ar, 37K

22. Precision measurements in nuclear/neutron  decay in the LHC era
nuclear and neutron decay, pion decay
limits on scalar/tensor couplings
obtained by CMS collaboration in
pp  e + MET + X channel
- S. Chatrchyan et al. (CMS Collab.)
J. High. Energ. Phys (2012) 023;
- CERN Rep. nr. CMS-PAS-EXO (2013)
O. Naviliat-Cuncic and M. Gonzalez-Alonso
Annalen der Physik 525 (2013) 600.
V. Cirigliano, et al.,
J. High. Energ. Phys (2013) 046

23. Conclusions and Outlook
- pure Fermi transition Ft-values, and possibly neutron decay parameters and correlation measurements in mirror  transitions
 contribute to further improving precision of Vud mixing matrix element;
- - correlation and  asymmetry measurements + Ft-values
 improved limits on scalar and tensor type weak currents;
- additional observable: beta-spectrum shape
 scalar/tensor currents and weak magnetism
polarized atoms/ions in trap would extend observables accessible with traps
- searches for new physics (bosons) at low energies remain competitive
with direct searches at LHC when concentrating on Fierz term and Vud
- many experiments ongoing or in preparation / planned