Transcript Document

The Weak Interaction
in
Low Energy Nuclear Physics
ARIS-2014
Tokio, June 1-6, 2014
b+
Nathal Severijns
ne
KU Leuven, Belgium
Overview
e+
-
recent / ongoing achievements
q
- APV and EDM
nucleus
ne
- Vud and unitarity / Ft-values
- exotic weak currents
(scalar, tensor, V+A)
(selected experiments showing diversity in techniques used)
-
new vistas and prospects
-
conclusion
and
outlook
for this field in
the LHC era
1. Atomic Parity Violation
&
Electric Dipole Moments
Atomic Parity Violation
probing sin2qW at atomic energies (test Standard Model)
206Fr
@ TRIUMF, LNL
223Ra @ KVI
enhancement factors of ~15 and ~50 compared to 133Cs case (Wiemann et al.)
Electric Dipole Moments
matter/anti-matter difference in the Universe
225Ra
@ ANL and KVI
223Rn @ TRIUMF
129Xe @ 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
2. Vud quark mixing matrix element & CKM unitarity
from
experiment
nucleus dependent
corrections
nucleus independent
|Vud| = 0.97425(22)
Hardy & Towner, PR C 79 (2009) 055502
|Vus| = 0.22564(53)
Dowdall et al., Phys. Rev. D 88, 074504 (2013)
V ud
= 3071.81(83) s
Towner & Hardy, Rep. Prog Phys. 73 (2010) 046301
2
 V us
2
 V ub
2
 0 .9 9 9 9 1(5 1)
prospects - 1
1. superallowed Fermi transitions
- new data for 0+  0+ pure Fermi transitions
- testing isospin corrections C
- nucleus-independent radiative correction R
2. corrected Ft values of T = 1/2 mirror b transitions and neutron decay
could contribute as well
Ft
m irror



fA 2 
K
0 0
   2 Ft
=
1 
2
2
V
f
G
V
(1


)
V
F
ud
R


N.S. , I.S. Towner et al.,
Phys. Rev. C 78(2008) 055501
 
C A M GT
CV M
O. Naviliat-Cuncic & N.S. , PRL 102 (2009) 142302
F
prospects - 2
2a. Neutron decay
- no nuclear structure related corrections
- issues of lifetime and asymmetry parameter first have to be resolved
2b. T = 1/2 mirror b 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:
35Ar
-
βn-corr. measurement performed with LPCTrap
: βn-corr. measurement performed with LPCTrap;
β-asym. measurement in preparation
(if A/A = 0.5%  Vud = 0.0004)
requires measurements of QEC, t1/2 and BR leading to Ft values for mirror transitions
N.S. & O. Naviliat-Cuncic, Physica Scripta T152 (2013) 014018
3. Exotic weak currents (scalar, tensor, V+A)
1. bn correlation
a
pe  q
exp.
a
a =
1  b
E e En
 me
w ith   1  ( Z )
2
Ee
2
'
| CS |  | Cs |
aF  1 
2
| CV |
2
'
bF

Re
CS  CS
CV
Fierz term
2
'
2
1 
| CT |  | CT | 
a GT  
1 

2
3 
| CA |


bGT 
Re
!!! for pure transitions weak interaction results are
independent of nuclear matrix elements !!!
CT
'
 CT
CA
scalar - TRINAT MOT trap at TRIUMF-ISAC – 38mK
search for scalar couplings
38m
K 
38
Ar + e
+
+ν
superallowed 0+  0+
pure Fermi transition
(t1/2 = 0.95 s)
A. Gorelov, J. Behr et al.,
Phys. Rev. Lett. 94 (2005) 142501
a
a =
1
 me
= 0 .9 981(30)(35)
b
Ee
| CS |  | C S |
2

| CV |
TOF
'
2
(90% C .L .)
2
 0.097
ongoing experiments in search for scalar weak currents:
- LPCTrap-GANIL (Paul):
- WITCH-ISOLDE (Penning):
- Jerusalem
(MOT):
- TamuTrap , Texas (Paul):
35Ar
19Ne
32Ar
(T=2, βp)
scalar: a = -1
WITCH
vector: a = +1
74.6 (1.0) %
Counts / time bin
35Ar
PS1-A065 – Delahaye
19Ne, 35Ar
35
a/a ~ 0.3%
3000
17.3 (0.4) %
35
5.7 (0.2) % Cl
1000
35
1.7 (0.2) % Cl
35
<1 % Cl
0
0
2
35
+
35Ar
(analysis in progress)
2000
Cl
Cl
2+
3+
4+
5+
4
6
8
Time of flight (s)
poster D. Zakoucky PS1-A061
LPCTrap - GANIL
10
12
Limits on scalar currents
= 3071.81(83) s
38mK:
Towner & Hardy, Rep. Prog Phys. 73 (2010) 046301
Gorelov, Behr et al.,
PRL 94 (2005) 142501
Tensor - LPCTrap @ GANIL - 6He / 35Ar
2006 (6He): aβν = −0.3335(73)stat(75)syst
X. Fléchard et al., J. Phys. G 38 (2011) 055101
experiment
fit
Counts
10000
Li2+
2010
6He
1000
Normalized
residuals
100
10
4
2
0
-2
-4
Li3+
a/a ~ 0.5 % (stat)
(analysis in progress)
charge-state distribution and
comparison to atomic theory:
C. Couratin
et al., PRL 108
(2012) 2432013000
2000
2500
TOF (ns)
Tensor -
6He
MOT Trap setup @ Univ. Washington, Seattle
P. Mueller, A. Garcia, et al.
1083 nm
6He
•
•
•
Trap/Detector Chamber
RF discharge -> metastable He*
Laser cooling @ 1083 nm
Timeline:
- 6He produced and trapped
- first data run in August 2013 --> 1 % measurement
- 0.1 % measurement by 2015
6He
Trapping Rates @ CENPA: @ source: 5x109 s-1 ; capt. efficiency = 2x10-7; @ trap: 1000 s-1
Trap-to-trap transfer: > 60% efficiency, ~15 ms
A. Knecht et al., NIM A 660 (2011) 43, Phys .Rev. C 86 (2012) 035506 & arXiv:1208.6433v2 [nucl-ex]
O. Aviv et al., J. Phys.: Conf. Ser. 337, 012020 (2012)
7/22/2015
13
N. Severijns, CGS14
conference - Aug. 28 -
Tensor - -b-n Correlation in Paul trapped 8Li Ions
G. Savard et al. (ANL, Mc. Gill, LLNL, Univ. Chicago, … )
8

L i  e  n e  2
aβν = −0.3307 (60)stat (67)sys
G.Li, G.Savard et al., PRL 110 (2013) 082502
data with ~20 times more statistics
+ lower systematics to be published
  1% or better
Poster PS2-B004 – Perez Galvan
Tensor - β asymmetry
– Leuven / ISOLDE / Prague
F. Wauters et al., NIM A 609 (2009) 156
region
analysed
Aexp (60Co) = - 1.014 (12)stat (16)syst
F. Wauters et al., Phys. Rev. C 82 (2010) 055502
Aexp (114In) = - 0.990 (10)stat (10)syst
F. Wauters et al., Phys. Rev. C 80 (2009) 062501(R)
F. Wauters
et al., Phys.
67
Aexp ( Cu) = 0.587(8)stat (12)syst
Rev.
C 80 (2009) 062501(R)
G. Soti et al., submitted to PR C
Constraints on tensor type weak couplings
a(6He)
-b-n(8Li)
A(60Co)
C. Johnston et al.,
PR 132 (1963) 1149
A(60Co)
A(67Cu)
F. Wauters, N.S. et al.,
PR C 82 (2010) 055502
-b-n(8Li)
G.Li, G.Savard et al.,
PRL 110 (2013) 082502
A(67Cu)
G. Soti, N.S. et al., (2013) submitted
a(6He)
New vistas and prospects in the LHC era - 1
- new generation of trap-based experiments

towards 0.1% precision level
- precise b-spectrum shape measurements
(Leuven-Krakow, MSU-NSCL, LPC Caen, … )

1
'
d   G F F ( Z , E ) 1  k
b F ierz  k E b bW M
Eb

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 !!
miniBETA spectrometer (Leuven / Krakow)
multi-wire drift chamber
scintillator
(later DSSDD)
poster P. Finlay PS2-CO23
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:
ULiège-KU Leuven:
-
19Ne
35Ar
collinear laser optical pumping
NSCL-BECOLA, ISOLDE-COLLAPS:
21Na, 23Mg, 35Ar, 37K
Precision measurements in nuclear/neutron b decay in the LHC era
90 % CL
nuclear and neutron decay, pion decay
O. Naviliat-Cuncic and M. Gonzalez-Alonso
Annalen der Physik (2013) in print.
V. Cirigliano, et al.,
J. High. Energ. Phys. 1302 (2013) 046
90 % CL
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. 1208 (2012) 023;
- CERN Rep. nr. CMS-PAS-EXO-12-060 (2013)
Conclusions and Outlook
-
pure Fermi transition Ft-values, and possibly neutron decay parameters
and correlation measurements in mirror b transitions
 contribute to further improving precision of Vud mixing matrix element;
-
b-n correlation and b asymmetry measurements + Ft-values
 improved limits on scalar and tensor type weak currents;
-
additional observable: beta-spectrum shape
 scalar/tensor currents and weak magnetism
-
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 planned / in preparation
Contributed talks and Posters
EDM - APV:
Par. 1C – Sato
PS1-A064 – Ohtomo
PS1-A066 – Ohtomo
PS1-A067 – Mueller
PS2-B001 – Kawamura
PS2-B002 – Teruya
PS2-B003 – Inoue
PS2-C020 – Harada (APV)
ββ-decay:
Par. 1C – Hinohara
PS1-A064 – Ringle
PS2-B006 – Yoshinaga
Superallowed Fermi:
Par. 1C – Laffoley
Par. 1C – Park
PS1-A062 – Blank
PS1-A063 – Nishimura
β-decay correlations:
and β-spectrum shape
PS1-A061 – Zakoucky
PS1-A065 – Delahaye
PS2-B004 – Perez Galvan
PS2-B005 – Mueller
PS2-C023 – Finlay (spectrum shape)
Backup slides
Ion/atom
for b-n
correlation
Most
precise traps
bn correlation
measurements
measurements
Particle traps: ideal sources
- sample is isotopically pure
- localized in a small volume
- atoms decay at rest
- detection of recoil ion
- negligible source scattering
Penning
- potential for polarized sample
MOT
Paul
Overview of b-n correlation projects
a = −0.3307(60)(67)
N.S. & O. Naviliat-Cuncic, Physica Scripta T152 (2013) 014018
MOT trap for radioactive Ne isotopes
G. Ron et al. (Hebrew Univ., Weizmann Inst. and SOREQ – Israel)
17,18,19,23,24Ne
- p/d accelerator
(5mA/up to 40MeV)
- neutron generator
Zeeman slower
G. Ron, priv. comm.
double-trap MOT concept
(similar to TRINAT)
WITCH @ ISOLDE -
35Ar
- scalar
(KU Leuven, Univ. Munster, ISOLDE, NPI Rez-Prague, LPC-Caen)
Goal : determine bn correlation for 35Ar with (a/a)stat  0.5 %
 measure energy spectrum of recoiling ions with a retardation spectrometer
scalar: a = -1
vector: a = +1
poster by Paul Finlay
M. Beck et al., Eur. Phys. J. A47 (2011) 45
M. Tandecki et al., NIM A629 (2011) 396
S. Van Gorp et al., NIM A638 (2011) 192
7/22/2015