the weak interaction in low energy nuclear physics

The Weak Interaction

in

Low Energy Nuclear Physics

Nathal Severijns

KU Leuven, Belgium

ARIS-2014Tokio, June 1-6, 2014

+

e

e+

e

nucleus

- 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

- conclusion and outlook

Overview

1. Atomic Parity Violation & Electric Dipole Moments

Atomic Parity Violation

Electric Dipole Moments

225Ra @ ANL and KVI223Rn @ TRIUMF129Xe @ 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

probing sin2W at atomic energies (test Standard Model)

206Fr @ TRIUMF, LNL223Ra @ KVI

enhancement factors of ~15 and ~50 compared to 133Cs case (Wiemann et al.)

matter/anti-matter difference in the Universe

2. Vud quark mixing matrix element & CKM unitarity

Towner & Hardy, Rep. Prog Phys. 73 (2010) 046301

= 3071.81(83) s

fromexperiment

nucleus dependent corrections nucleus independent

2 2 2 0.99991(51)ud us ubV V V

|Vus| = 0.22564(53)

|Vud| = 0.97425(22)

Hardy & Towner, PR C 79 (2009) 055502

Dowdall et al., Phys. Rev. D 88, 074504 (2013)

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 transitions and neutron decay could contribute as well

A GT

V F

C M

C M 2 0 0

2 21 2 =

(1 )A

V

mirrorV

F ud R

f

f

KFt Ft

G V

O. Naviliat-Cuncic & N.S. , PRL 102 (2009) 142302N.S. , I.S. Towner et al.,

Phys. Rev. C 78(2008) 055501

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 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

(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)

e

e

p qa

E E

= 1

e

e

mb

E

aa

2with 1 ( )Z

2A

2'T

2T

2V

2's

2S

|C|

|C| |C| 1

3

1

|C|

|C| |C| 1

GT

F

a

a

A

'TT

V

'SS

C

C C e

C

C C e

Rb

Rb

GT

F

Fierz term

1. correlation

exp.

!!! for pure transitions weak interaction results are independent of nuclear matrix elements !!!

search for scalar couplings

scalar - TRINAT MOT trap at TRIUMF-ISAC – 38mK

38m 38 +K 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

= 0 = .9 1

981(30)(35)e

e

aa

mb

E

2 ' 2

2

(90% C.L.)

| | | | 0.097

|

|SS

V

C C

C

TOF

ongoing experiments in search for scalar weak currents:

- LPCTrap-GANIL (Paul): 19Ne, 35Ar PS1-A065 – Delahaye

- WITCH-ISOLDE (Penning): 35Ar

- Jerusalem (MOT): 19Ne

- TamuTrap , Texas (Paul): 32Ar (T=2, βp)

35Ara/a ~ 0.3%(analysis in progress)

scalar: a = -1

vector: a = +1

35Ar

LPCTrap - GANIL

WITCH

poster D. Zakoucky PS1-A061

preliminary

preliminary

Limits on scalar currents

Towner & Hardy, Rep. Prog Phys. 73 (2010) 046301

38mK: Gorelov, Behr et al., PRL 94 (2005) 142501

= 3071.81(83) s

Tensor - LPCTrap @ GANIL - 6He / 35Ar

2006 (6He): aβν = −0.3335(73)stat(75)syst

X. Fléchard et al., J. Phys. G 38 (2011) 055101

Li3+

Li2+

a/a ~ 0.5 % (stat) (analysis in progress)

20106He

charge-state distribution and comparison to atomic theory:

C. Couratin et al., PRL 108 (2012) 243201

1083 nm

T

Tensor - 6He MOT Trap setup @ Univ. Washington, SeattleP. Mueller, A. Garcia, et al.

• 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 Trap/Detector Chamber

Trap-to-trap transfer: > 60% efficiency, ~15 ms

6He Trapping Rates @ CENPA: @ source: 5x109 s-1 ; capt. efficiency = 2x10-7; @ trap: 1000 s-1

A. Knecht et al., NIM A 660 (2011) 43, Phys .Rev. C 86 (2012) 035506 & arXiv:1208.6433v2 [nucl-ex]

PS2-B005 – Mueller

04/20/23 13 N. Severijns, CGS14 conference - Aug. 28 - Sept. 02, 2011

O. Aviv et al., J. Phys.: Conf. Ser. 337, 012020 (2012)

8 2eLi e

aβν = −0.3307 (60)stat (67)sys

G.Li, G.Savard et al., PRL 110 (2013) 082502

Tensor - -- Correlation in Paul trapped 8Li IonsG. Savard et al. (ANL, Mc. Gill, LLNL, Univ. Chicago, … )

data with ~20 times more statistics + lower systematics to be published

1% or betterPoster PS2-B004 – Perez Galvan

F. Wauters et al., Phys. Rev. C 80 (2009) 062501(R)

Aexp (60Co) = - 1.014 (12)stat (16)syst

Aexp (114In) = - 0.990 (10)stat (10)syst

Aexp (67Cu) = 0.587(8)stat (12)syst

F. Wauters et al., Phys. Rev. C 80 (2009) 062501(R)

F. Wauters et al., Phys. Rev. C 82 (2010) 055502

regionanalysed

G. Soti et al., submitted to PR C

Tensor - β asymmetry – Leuven / ISOLDE / Prague

F. Wauters et al., NIM A 609 (2009) 156

Constraints on tensor type weak couplings

A(60Co)

A(67Cu)

a(6He)

--(8Li)

a(6He)C. Johnston et al.,

PR 132 (1963) 1149 A(60Co)F. Wauters, N.S. et al.,

PR C 82 (2010) 055502

--(8Li)G.Li, G.Savard et al.,

PRL 110 (2013) 082502

A(67Cu)G. Soti, N.S. et al., (2013) submitted

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 !!

'1 ( , ) 1 k F Fierz WMd G F Z E b k E b

E

miniBETA spectrometer (Leuven / Krakow)

multi-wire drift chamber scintillator(later DSSDD)

poster P. Finlay PS2-CO23

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

access to A and other correlations involving nuclear spin

New vistas and prospects in the LHC era - 2

- perform more measurements with polarized nuclei

O. Naviliat-Cuncic and M. Gonzalez-AlonsoAnnalen der Physik (2013) in print.

V. Cirigliano, et al., J. High. Energ. Phys. 1302 (2013) 046

Precision measurements in nuclear/neutron decay in the LHC era

90 % CL90 % CL

nuclear and neutron decay, pion decay limits on scalar/tensor couplingsobtained 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)

- 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

- 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

Conclusions and Outlook

EDM - APV: Par. 1C – SatoPS1-A064 – OhtomoPS1-A066 – OhtomoPS1-A067 – MuellerPS2-B001 – KawamuraPS2-B002 – TeruyaPS2-B003 – InouePS2-C020 – Harada (APV)

ββ-decay: Par. 1C – HinoharaPS1-A064 – RinglePS2-B006 – Yoshinaga

Superallowed Fermi: Par. 1C – LaffoleyPar. 1C – ParkPS1-A062 – BlankPS1-A063 – Nishimura

β-decay correlations: PS1-A061 – Zakouckyand β-spectrum shape PS1-A065 – Delahaye

PS2-B004 – Perez GalvanPS2-B005 – MuellerPS2-C023 – Finlay (spectrum shape)

Contributed talks and Posters

Backup slides

Most precise correlation 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

- potential for polarized samplePenning

MOTPaul

Ion/atom traps for - correlation measurements

Overview of - correlation projects

N.S. & O. Naviliat-Cuncic, Physica Scripta T152 (2013) 014018

a = −0.3307(60)(67)

MOT trap for radioactive Ne isotopes G. Ron et al. (Hebrew Univ., Weizmann Inst. and SOREQ – Israel)

Zeeman slower

double-trap MOT concept (similar to TRINAT)

17,18,19,23,24Ne

- p/d accelerator (5mA/up to 40MeV)

- neutron generator

G. Ron, priv. comm.

04/20/23

Goal : determine correlation for 35Ar with (a/a)stat 0.5 %

measure energy spectrum of recoiling ions with a retardation spectrometer

WITCH @ ISOLDE - 35Ar - scalar(KU Leuven, Univ. Munster, ISOLDE, NPI Rez-Prague, LPC-Caen)

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

preliminary