Decay Correlations

Fundamental Neutron Physics Summer School 2015

Gertrud KonradAtominstitut, TU Wien, Austria

Stefan‐Meyer‐Institut Wien, ÖAW, Austria

The University of Tennesse, Knoxville 14‐20 June 2015

Thanks for contributions from:H. Abele, S. Baeßler, F. Wietfeldt, A. Young

Energy generation within the Sun

Sun eruption, August 31, 2012, NASA‘s Solar Dynamics Observatory

Energy generation within the Sun

2e

222

11 30 0

A

V

0.42MeV

S 6 ln 2R

ppp

p p H e

f EEE m

ftgg

Rate for initial reaction in the pp chain

Sun eruption, August 31, 2012, NASA‘s Solar Dynamics Observatory

Current status of

Lattice QCD PDG 2014

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

T. Bhattacharya et al., Phys. Rev. D 85, 054512 (2012)

PDG 2011

Ag

K.A. Olive et al. (PDG), Chin. Phys. C 38, 090001 (2014)

A Vg g

Properties of the Neutron

June 19, 2015 G. Konrad, TU & SMI Wien, Austria

• Charge: < 10-21 e neutral

• Mass: 1838.683 me 939.565 MeV/c2

• Spin: ½ ħ• Lifetime: 880.3(1.1) s

( ) . 2n p e 782 334keVQ m m m m c

+n p e e Q

Decay Correlations, Summer School Knoxville

quark mixing

coupling strength

A Vg g decay

. .

2n

ud2

4908 7 1 9 s1

1 3V

V F udg G VA. Czarnecki et al., PR D 70, 093006 (2004)

Fermi transitions

Gamow-Teller transitions A F udg G V

Outline

• Motivation

• Neutron beta‐decay within the Standard Model

• Searches for new physics beyond the Standard Model

• Summary and Outlook

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

The Neutron Alphabet I

3

22F

22ud e e 0 e5

e e

d 1 1 3d d d 2 2

G V p E E EE

ne e e

e n e

e

ee

1 p p p p p pE E E E E E

a A B DmE

b

J.D. Jackson et al., PR 106, 517 (1957)

-1n

• 3 unknown parametersGF, Vud,

• 20 or more observables

n, a, b, A, B, C, D, …• yet unmeasured

b

A Vg g

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

Determination of the decay correlations

Leptons

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

ProtonNeutron

Matrixelements

Clebsch‐Gordon

Fermi

Gamow‐Teller

, JJ m

based on J. Döhner, PhD thesis, Uni Heidelberg, 1990

Determination of neutrino‐electron correlation a

same opposite

same opposite

N NN N

a

Fermi

Gamow‐Teller

, JJ m

a=1

a=1

a=-1

2 222 2 2 2

V F A GT A GT V A A2 2 2 2 2

V AV F A GT

1 3 2 3 2 13 1 3

g M g M g M g g gg gg M g M

a

Current status of the decay correlations

2

2

cos2

1 3B

0.27484C A B

2

2

1

1 3a

2

2

cos2

1 3A

2

sin2 0

1 3D

180

Observable Standard Model Status PDG 2014

Lifetime τn/τn 0.1%

Ratio of weak coupling constants / 0.2%

Neutrino‐electron correlation a/a 3.9%

Fierz interference term b = 0 yet unmeasured

Beta asymmetry A/A 0.8%

Neutrino asymmetry B/B 0.3%

Proton asymmetry C/C 1.1%

Triple correlation D = (‐1 2) × 10‐4 = (180.02±0.03)°

u

n 2 2d

4908.7 1.9 s11 3V

A Vig g e

K.A. Olive et al. (Particle Data Group), Chin. Phys. C 38, 090001 (2014)

Weak magnetism

• 3 unknown parametersGF, Vud,

• 20 or more observables

n, a, b, A, B, C, D, …

• yet unmeasuredb, f2

2

2

11 3

a

2

2

Re2

1 3A

ee WM

e2%

21 ,A A Eam

fE c

A Vg g

3

22 22F ud e e 0 e5

e e

d 1 1 3d d d 2 2

p E E EE

G V

ne e e

e n e

e

ee

1 p p p p p pE E E E E E

a A B DmE

b

M. Gell‐Mann, Phys. Rev. 111(1), 362 (1958)

Beyond the Standard Model physics

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

• Study the structure of the weak interaction value of weak magnetism form‐factor f2 predicted (CVC hypothesis) value f2 = (κp-κn)/2 ≈ 1.8529 tested only to O(10%) in A=12 system large theoretical uncertainties

• Test the Standard Model of particle physics self‐consistency of the Standard Model unitarity of the Cabibbo‐Kobayashi‐Maskawa (CKM) quark‐mixing matrix

superallowed 0+→ 0+ decays

Present best test of the Standard Model

2 2 2 4us uu bd1 1 1 6 10V VV

Kaon decays B‐decays

September 4, 2014 Testing CVC and CKM unitarity via SAF-β-decay, Solvay Workshop Brussels 2014 Courtesy of J. Hardy

Determination of

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

A Vg g

K.A. Olive et al. (PDG), Chin. Phys. C 38, 090001 (2014)

A

A BA B

C

Measurement of beta asymmetry parameter A2

ene

e e

d 1 cosd d

vE c

A ne

Electron energy spectra

2same opposite

2same opposite

21 3

N NN N

A

The PERKEO II experiment @ ILL

• Cold neutron beam from H113 @ ILL• Neutron beam preparation (polarization, spin flip, collimation)• Neutron beam analysis• Electron spectroscopy with PERKEO II spectrometer• Beam stop

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

H. Abele et al., Phys. Lett. B 407,212 (1997)H. Abele et al., Phys. Rev. Lett. 88, 211801 (2002)

The spectrometer PERKEO II

Systematic uncertainties:• Background• Detector response: monoenergetic conversion electron sources• Edge effect• Electron backscattering: second scintillation detector• Magnetic mirror effect (adiabatic invariant )

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

e eexp,i e

e e

i i

i i

N E N EN

A EN E E

1T

e eexp e ne

1= cos2

v vE Pf PfA Ac

Ac

2p B

Latest PERKEO II resultsBackground subtraction

Energy calibration

Energy spectra

Asymmetry spectra

H. Abele, NIM A 611, 193 (2009)D. Mund et al., PRL 110, 172502 (2013)D. Mund, Ph.D. thesis, Uni Heidelberg, 2006

47530.11926A

Spin down

Spin up

Channel

Energy

Channe

l

Energy

Channel

Detector

Neutrons

Resulting electron signal

Background signalwith shutter up closed

The successor PERKEO III @ ILL

• Large decay volume: count rate increased by ca. one order of magnitude• Pulsed neutron beam: background suppression

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

B. Märkisch et al., NIM A 611, 216 (2009)

SM polarizer

casemate

150 mT

Preliminary ‛results‘ from PERKEO III

Energy spectra Asymmetry spectrum

31.9 10A A

fourfoldimprovementcompared to PDG

Result still blinded

H. Mest, Ph.D. thesis, Uni Heidelberg, 2011H. Saul, Ph.D. thesis, TU Wien, in progress

TOF spectra

A new approach to A: UCNA @ LANSCE

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

Latest results from UCNA

Energy spectrum

Asymmetry spectrum

Corrections

0.11952 110A

J. Liu et al., PRL 105, 181803 (2010)B. Plaster et al., PR C 86, 055501 (2012)M.P. Mendenhall et al., PR C 87, 032501(R) (2013)

Future prospects: The new facility PERC @ FRM II

high flux ϕ=2×1010 cm-2s-1 and high decay rate =1×106 m-1s-1

improved by up to 2 orders of magnitude to sub‐10‐4‐level highest phase space dΩe , dΩp densities

• Statistics:• Sensitivity:

cold neutrons

velocityselector chopper

polarizer & spin flipper, 5m

neutron guide=0.5T

D. Dubbers et al., NIM A 596, 238 (2008) G. K. et al., J. Phys.: Conf. Ser. 340, 012048 (2012)

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

Limitation of electron/proton divergenceCritical angleMagnetic mirror field Count rate

Beta asymmetry Figure of merit

D. Dubbers et al., NIM A 596, 238 (2008)

G. K. et al., J. Phys.: Conf. Ser. 340, 012048 (2012)

1 1

0 0

sinsin

BB

Future prospects: The new facility PERC @ FRM II

high flux ϕ=2×1010 cm-2s-1 and high decay rate =1×106 m-1s-1

improved by up to 2 orders of magnitude to sub‐10‐4‐level highest phase space dΩe , dΩp densities

precise cuts in dΩe , dΩp :

≤ 10‐4 (for e‐), especially ΔP/P=10-4

a, b, A, B, C, f2, …

manufacturing within 18, commissioning within 24 months beam site at FRM II/Garching (DE) under construction

1 1

0 0

sinsin

BB

• Statistics:• Sensitivity:

• Systematics:

• Versatility:• Status:

cold neutrons

velocityselector chopper

polarizer & spin flipper, 5m

neutron guide=0.5T

D. Dubbers et al., NIM A 596, 238 (2008) G. K. et al., J. Phys.: Conf. Ser. 340, 012048 (2012)

C. Klauser, PhD thesis, TU Wien, 2013C. Klauser et al., J. Phys.: Conf. Ser. 340, 012011 (2012)

Detection systems for PERC

Observable Correlations Measurement principle Examples

β and p momenta

a, b, A Magnetic spectrometerPLUS position sensitive detectors

β energy A, B, b, f2, g2radiativecorrections

β energy sensitive detectors such asscintillation OR silicon detectors

PERKEO I‐III UCNA

p energy a, C Retardation spectrometer PLUS p detector aSPECT

p velocity a, C Wien filter PLUS position sensitive detector

p TOF a p beam pulsed by electric gate voltagePLUS p detector

Sensitivity of decay correlations on

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

aAB

aAB

A Vg g

PDG 201

4

Determination of from a

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

A Vg g

Measurement of neutrino‐electron correlation a

e

a < 0

Tp small

n

νe

p+

e-a > 0

Tp large

n

νe

p+

e-

ecos 1 ecos 1 Recoil energy spectrum

2e

ee e

d 1 cosd d

vE c

a

The retardation spectrometer aSPECTProton transmission function

F. Glück et al., EPJ A 23, 135 (2005)S. Baeßler, G. K. et al., EPJ A 38, 17 (2008)G. Konrad et al., NP A 827, 529c (2009)

current goal: 1-2 %design goal: 0.3 %

2p B

The retardation spectrometer aSPECTIntegral proton spectrum

current goal: 1-2 %design goal: 0.3 %

Crucial prerequisite: background• stable over time • independent of analyzing plane voltage

F. Glück et al., EPJ A 23, 135 (2005)S. Baeßler, G. K. et al., EPJ A 38, 17 (2008)G. Konrad et al., NP A 827, 529c (2009)

aSPECT beam time 2013

R. Maisonobe, PhD thesis, UJF Grenoble, 2014A. Wunderle et al., in: Proc. of PANIC2014, submitted

p0

p1

10 1 exp tt pf p

Backgroundwithout neutron beam

Background time evolutionwith neutron beam

Ansatz:

no additional E×B

|Size| of correction:• no additional E×B: ≈ 1 %

Current goal: 1‐2 %

G. K., PhD thesis, JGU, 2011

aSPECT beam time 2013Backgroundwithout neutron beam

Background time evolutionwith neutron beam

R. Maisonobe, PhD thesis, UJF Grenoble, 2014A. Wunderle et al., in: Proc. of PANIC2014, submitted

10 1 exp tt pf p

|Size| of correction:• no additional E×B: ≈ 1 %• additional E×B: < 0.1%

Ansatz:

p0

p1

Current goal: 1‐2 %

additional E×B

G. K., PhD thesis, JGU, 2011

A new approach to a: aCORN @ NIST

INDIANAUNIVERSITY

current goal: < 5 %design goal: 0.5 %

F.E. Wietfeldt et al., NIM A 538, 574 (2005),NIM A 545, 181 (2005), NIM A 611, 207 (2009)

Measurement principleB. Yerozolimsky et al., arXiv:nucl‐ex/0401014, 2004

aCORN data (2013)

aCORN data

aCORN data5.0

4.5

4.0

3.5

3.0

2.5

2.0

prot

ontim

eof

fligh

t(s

)

10008006004002000beta energy (keV)

sample of aCORN data (2013)

5.0

4.5

4.0

3.5

3.0

2.5

2.0

prot

on ti

me

of fl

ight

(s)

1000800400 600beta energy (keV)

2000

aCORN Monte Carlo

current goal: < 5 %design goal: 0.5 %

Future prospects for a: Nab @ SNS / abBA

Ee [MeV]

p p2

[MeV

2 /c2 ]

cos θeν = 1

Proton phase space (Dalitz plot) Probability (arb. units)

0

0.25

0.5

0.75

1

1.25

1.5

0 0.2 0.4 0.6 0.8

cos θeν = 0cos θeν = -1

Ee =

236 keV

450 keV

700 keV

Kinematics in INM approximation

• energy conservation

• momentum conservation2 2 2

e ep 2 cos ep p p p p

e,max eEE E

2ep

e

1 cos epa pE

22p emin, max

p p p

Edges

Slope

D. Počanić et al., NIM A 611, 211 (2009)

2e

ee e

d 1 cosd d

vE c

a

The Nab spectrometer

design goal: 0.1 %

SegmentedSi detector

decay volume (field rB,DV·B0)

0 kV

0 kV

-30 kV

magnetic filterregion (field B0)

Neutronbeam

TOF region(field rB·B0)

Sim

ulat

ed c

ount

s [a.

u.]

0.002 0.004 0.0060

Ee = 300 keVEe = 500 keVEe = 700 keV

1/tp2 [µs-2]

D. Počanić et al., NIM A 611, 211 (2009)S. Baeßler et al., arXiv:1209.4663v1 [nucl-ex], 2012A. Salas-Bacci et al., NIM A 735, 408 (2014)

Proton 1/tp2 histograms:

pp

p pcosm dztp z

Outline

• Motivation

• Neutron beta‐decay within the Standard Model

• Searches for new physics beyond the Standard Model

• Summary and Outlook

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

Decay parameters

• 10 unknown parametersGF, Vud, Cj, Cjꞌ, j=V, A, S, T

• 20 or more observables

n, a, b, A, B, C, D, …• Coupling constants Lj to left‐

handed and Rj to right‐handed neutrinos

F. Glück et al., NP A 593, 125 (1995)

F ud

2 j jj LG RVC F ud

2 jj jRG VC L

3

22 22F ud e e 0 e5

e e

d 1 1 3d d d 2 2

p E E EE

G V

ne e e

e n e

e

ee

1 p p p p p pE E E E E E

a A B DmE

b

Decay correlations

2 2 2 22 2 2 2V A S T V A S TL L L L R R Ra R

* * * *2 3 3S V A T S V A TL L L L R R R Rb

2 2 2 2* * * *2 A V A T S T A V A T S TL L L L L L R R R R RA R

F. Glück et al., NP A 593, 125 (1995)

• 10 unknown parameters: GF, Vud, Lj, Rj, j=V, A, S, T

• 20 or more observables: n, a, b, A, B, C, D, …

2 2 2 22 2 2 23 3 3 3V A S T V A S TL L L L R R R R

yet unmeasured

3

22 22F ud e e 0 e5

e e

d 1 1 3d d d 2 2

p E E EE

G V

ne e e

e n e

e

ee

1 p p p p p pE E E E E E

a A B DmE

b

Prospects for scalar and tensor interactions

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

b at 10‐3 level precision LHC limits

CMS search for → X

1

1 ∙

M. González‐Alonso, O. Naviliat‐Cuncic, NPAC‐13‐03; arXiv:1304.1759see also: G. Konrad et al., in: Proc. 5th BEYOND 2010, World Scientific, 660, 2011, arXiv: 1007.3027v2 (2010)

Prospects for scalar and tensor interactions

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

b at 10‐4 level precision

CMS search for → X

1

1 ∙

LHC limits

T. Bhattacharya et al., PR D85,054512 (2012)M. González‐Alonso, O. Naviliat‐Cuncic, NPAC‐13‐03; arXiv:1304.1759

Beyond the Standard Model physics• Study the structure of the weak interaction

value of weak magnetism form‐factor f2 predicted (CVC hypothesis) value f2 = (κp-κn)/2 ≈ 1.8529 tested only to O(10%) in A=12 system large theoretical uncertainties

• Test the Standard Model of particle physics self‐consistency of the Standard Model unitarity of the Cabibbo‐Kobayashi‐Maskawa (CKM) quark‐mixing matrix

• Search for ‘new physics beyond‘ and new symmetry concepts left‐right symmetry, leptoquarks, supersymmetry (SUSY), etc. right‐handed admixtures, exotic scalar and tensor admixtures can continue to probe for SUSY in regions where it is not accessible to LHC deviations from CKM unitarity ≥ 10‐4 fall in the LHC inaccessible region 10‐3 level b measurements complementary to improved LHC results

superallowed 0+→ 0+ decays

Present best test of the Standard Model

2 2 2 4us uu bd1 1 1 6 10V VV

Kaon decays B‐decays

Measurement of the Fierz interference term b

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

Electron energy spectrum

‛Prototype‘ of a UCN calorimeter: UCNb @ LANSCE

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

PMTs

PMTs

b box

UCN ball valve

UCN guide

Calibrationinsert

K. Hickerson, Ph.D. thesis, Caltech, 2012

Electron energy spectrum

Future prospects for b: Nab @ SNS

design goal: 0.003

Systematic uncertainties• Electron energy determination:

• Background

2% of events in tail(deadlayer, external bremsstrahlung)

Yie

ld1

101

102

103

104

105

detected Ee [keV] 0 50 100 150 200 250 300

Detector response to decayelectron with Ee = 300 keV

Electron energy spectrum

D. Počanić et al., NIM A 611, 211 (2009)S. Baeßler et al., arXiv:1209.4663v1 [nucl-ex], 2012

Future prospects for b: PERC @ FRM II

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

Electron energy spectrum Electron momentum spectrum

Magnetic spectrometer @ PERC

no low momentum measurements large corrections for θ non‐adiabatic transport of particles B2‐field coupled with B3‐field pitch angles easily distorted

+ large drift distances O(dm)

B2=0.5TB3=0.01T

3 3

, cosprB B

ppq q

Radius of gyration:

R×B drift momentum spectrometer: NoMoS

Last Coil of PERC

Tilted Coils

e‐/p+ beam

Detector

Aperturey

zx

B3=0.15T

B2=0.5T

α

DDR×Bvd qR²B²

y

xz

ElectronsProtons

X. Wang, G. K., H. Abele, NIM A 701, 254 (2013)

+ extremely versatile+ adiabatic transport of particles+ low momentum measurements+ small corrections for θ+ large acceptance of θ

RB

3

1, (cos )c

d 1os2dT B

v tDq

pp

R×B drift momentum spectrometer: NoMoS

Last Coil of PERC

Tilted Coils

e‐/p+ beam

Detector

Aperture

B3=0.15T

B2=0.5T

α

DDElectronsProtons

+ extremely versatile+ adiabatic transport of particles+ low momentum measurements+ small corrections for θ+ high resolution:

Δp/p=14.4 keVc-1mm-1

small drift distances O(cm)

1.2%mm‐1

X. Wang, G. K., H. Abele, NIM A 701, 254 (2013)

R×Bvd qR²B²

y

zx

y

xz

3

1, (cos )c

d 1os2dT B

v tDq

pp

RB

Decay correlations

* * * * * *2 2 2S A V T A T S A V T A TL L L L L L R R R R R Rb

2 2 2 2* * * *2 A V A T S T A V A T S TL L L L L L R R R R RA R

F. Glück et al., NP A 593, 125 (1995)

• 10 unknown parameters: GF, Vud, Lj, Rj, j=V, A, S, T

• 20 or more observables: n, a, b, A, B, C, D, …

2 2 2 22 2 2 23 3 3 3V A S T V A S TL L L L R R R R

yet unmeasured

3

22 22F ud e e 0 e5

e e

d 1 1 3d d d 2 2

p E E EE

G V

ne e e

e n e

e

ee

1 p p p p p pE E E E E E

a A B DmE

b

0e

e

B bB mE

2 2 2 2* * * *0 2 A V A T S T A V A T S TL L L L L L R R R R R RB

Signal for MSSM expected at 3~ 10B S. Profumo et al., PR D 75, 075017 (2007)

Measurement of neutrino asymmetry parameter B2

en

e

d 1 cosd d

vE c

B

n

2same opposite

2same opposite

21 3

N NN N

B

Electron energy spectra

Spin down, electron down, proton up

Spin up, electron down, proton up

Spin down, electron up, proton up

Spin up, electron up, proton up

The spectrometer PERKEO II

e eexp e

e e

N EB

N EE

N E N E

2e

2e

exp ee

e

2 3 31

8 4 24=3 2

14

A B

a

v r rc rvr rP cE

v rc rvr

c

BA B

a

e e e

max

v E mrc E E

Background B‐n‐displacement

0.9802 50B Limit on ‛right‐handed‘ W boson:

2R 296 GeV/cm W

M . Schumann et al., PRL 99, 191803 (2007)

A new approach to B0 and b: UCNB @ LANSCE

design goal: 0.1 %

A. Salas‐Bacci et al., NIM A 735, 408 (2014)

Measurement of proton asymmetry parameter C

2

p p npp p

d 1 , cosd d

C TE

np

Proton energy spectra

same opposite

same opposite

0.27484C A BN NN N

The spectrometer PERKEO II

exp e

Q Q Q QE

Q Q Q QC

M . Schumann et al., PRL 100, 151801 (2008)

0.2377 26C

The successor PERKEO III

goal: 0.2 %

accel. potential- 30 kV

0 V0 V 0 V

proton energy filter0V to +1 kV

magnetic field

photomultipliertubes

p e

scintillator withconductive coating

protonconversion foil

e

from neutrondecay volume

A similar approach: PANDA @ SNS

T. Chupp et al.

goal: 0.1 % p pdC T TC

The Neutron Alphabet I

3

22F

22ud e e 0 e5

e e

d 1 1 3d d d 2 2

G V p E E EE

ne e e

e n e

e

ee

1 p p p p p pE E E E E E

a A B DmE

b

J.D. Jackson et al., PR 106, 517 (1957)

-1n

• 3 unknown parametersGF, Vud,

• 20 or more observables

n, a, b, A, B, C, D, …

• yet unmeasuredb

A Vg g

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

221 3

D

Measurement of D coefficient: TRINE @ ILL

D = (–2.86.4stat3.0syst)·10-4

T. Soldner et al, Phys. Let. B 581, 49 (2004)

e p

3n e

e e n

n

e

p

n e

ed 1 1d d d p p p

p p DE E E

pD

E Ep

ep

ppp

00 01 10 11

004 D

DP

e ,p e ,p

e ,p e ,p

i j i jij

i j i j

N NN N

with

Measurement of D coefficient: emiT @ NIST

T Chupp et al, PR C 86, 035505 (2012)L.J. Lising et al., PR C 62, 055501 (2000)

D = (–0.941.89stat0.97syst)·10-4

e p

3n e

e e n

n

e

p

n e

ed 1 1d d d p p p

p p DE E E

pD

E Ep

The Neutron Alphabet II

2

22 22F ud e e 0 e4

e

d 1 1 3d d 2 2

G p E EV EE

n n ne e ee

e n e n n e

1 m p pb AE E E

N R

J.D. Jackson et al., PR 106, 517 (1957)

-1n

2 2 2 2* * * *e

e

2 A T V A S T A T V A S Tm L L L L L L R R R R R RE

N

* * * * * *2 2V T S A T A V T S A T AL L L L L L R R R R R R

F. Glück et al., NP A 593, 125 (1995)

2 2 2 22 2 2 23 3 3 3V A S T V A S TL L L L R R R R

2 2 2 2* * * *e

e

2 2 2 2A T V A S T A T V A S Tm L L L L L L R R R R Rp

R R

* * * * * *2 2 2V T S A T A V T S A T AL L L L L L R R R R R R

• 10 unknown parameters: GF, Vud, Lj, Rj, j=V, A, S, T

• 20 or more observables: n, a, b, A, B, C, D, N, R, …

The nTRV experiment @ PSI

e

pe

ppJn

p

2n n e

ee n n e

d 1d d

N pE E

R

Mott scattering

A. Kozela et al, PR C 85, 045501 (2012)A. Kozela et al., PRL 102, 172301 (2009)

Up‐down asymmetry

NSM = 0.066

Forward‐backward asymmetry

RSM = 0.00066

N = +0.0670.011stat0.004syst

R = +0.0040.012stat0.005syst

Rare decay modes• Radiative neutron β‐decay

electron innerBremsstrahlung (IB) proton IB weak‐vertex IB etc.

radiative corrections to continuum state β‐decay

• Bound state neutron β‐decay

hyperfine levels of metastable 2S state (for gS=gT=0)

signature for right‐handed currents

-3QEDBR =2.81 10en p e

6BR 4 10en H

d

u

W±

e-

νe

d

u

W±

e-

νe

d

u

W±

e-

νe

g gg

1 1 1 1 1 1, 0.6%, , 55.2%, , 44.2%,2 2 2 2 2 2

1 1and , 0; 02 2

Radiative neutron β‐decay: RDK @ NIST

en p e

R.L. Cooper et al., PR C81, 035503 (2010)

J. Nico et al., Nature 444, 1059 (2006)

stat syst -3expBR = 3.09 0.11 0.30 10

Bound state neutron β‐decay: BOB @ FRM II

J. McAndrew et al., Hyp. Int. 210, 13 (2012)W. Schott et al., Eur. Phys. J. A 30, 603 (2006)

Configuration gS = 0, gT = 0 gS = 0.1, gT = 0 gS = 0, gT = 0.1

44.14 % 46.44 % 43.40 %

55.24 % 53.32 % 55.82 %

0.622 % 0.238 % 0.780 %

0.0 % 0.0 % 0.0 %

1 1,2 2

1 1,2 2

1 1,2 2

1 1,2 2

September 12, 2013 Tests of Lorentz symmetry in neutron decay, PSI2013 Courtesy of J.S. Diaz

September 12, 2013 Tests of Lorentz symmetry in neutron decay, PSI2013 Courtesy of J.S. Diaz

September 12, 2013 Tests of Lorentz symmetry in neutron decay, PSI2013 Courtesy of J.S. Diaz

Summary & Outlook

• Neutron alphabet deciphers the Standard Model of particle physics observables in neutron β‐decay are abundant

• Precision measurements of neutron β‐decay address important open questions of particle physics and cosmology can continue to probe for SUSY in regions where it is not accessible to LHC 10‐3 level b measurements complementary to improved LHC results

• Rich experimenal program• New physics might be found. Maybe soon.

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria

Further reading

• H. Abele, Prog. Part. Nucl. Phys. 60, 1 (2008)• S Baeßler et al., J. Phys. G: Nucl. Part. Phys. 41, 114003 (2014)• V. Cirligiano, S. Gardner, B. Holstein, Prog. Part. Nucl. Phys. 71, 93 (2013)• D. Dubbers & M.G. Schmidt, Rev. Mod. Phys. 83, 11111171 (2011)• A.N. Ivanov, M. Pitschmann & N.I. Troitskaya, Phys. Rev. D 88, 073002

(2013)• J. Nico & M. Snow, Annu. Rev. Nucl. Part. Sci. 55, 27 (2005)• A.R. Young et al., J. Phys. G: Nucl. Part. Phys. 41, 114007 (2014)• etc.

June 19, 2015 Decay Correlations, Summer School Knoxville G.Konrad, TU & SMI Wien, Austria