Hartmut Abele Knoxville, 8 June 2006 Neutron Decay Correlation Experiments

Hartmut AbeleKnoxville, 8 June 2006

Neutron DecayCorrelation Experiments

Hartmut Abele, University of Heidelberg 2

Neutron Beta Decay2 2 2 2 2

03 7 3

1( ) (1 3 ) ( )

2 F udW pdp p E E dpG Vc

Electron

Neutron Spin

ElectronNeutron SpinA

W()={1+v/cPAcos()}

Detector

Detector


Coefficient A

Coefficient A and lifetime determine Vud and

Electron

Neutron Spin


W()={1+v/cPAcos()}

231

)1(2

A 231

)1(2

A

on flipper spin with spectrum electron

off flipper spin with spectrum electron

:N

:N

on flipper spin with spectrum electron

off flipper spin with spectrum electron

:N

:N

PfAAc

vexp PfAA

c

vexp

= gA/gV= gA/gV

No coincidences !

)31(

sec249082

2

udV)31(

sec249082

2

udV

2 2

0 0

(1 cos )sinv

N P dA dc

NN

NNAexp

NN

NNAexp A

N N

N Nexp

A

N N

N Nexp


For a correlation coefficient A measurements, we need …

Neutronsa Polarizera Spin Flipperan Analyzer

a Spectrometer


Correlation measurements in -decay

Electron

Proton

Neutrino

Neutron SpinA

B

C Observables in neutron decay:

Lifetime SpinMomenta of decay particles

Observables in neutron decay:

Lifetime SpinMomenta of decay particles

n n p e p e eeaa

DD

RRNN


Parameters and Observables

SM ParametersStrength: GF

Quark mixing: Vud

Ratio: = gA/gV

2 2 2 2 203 7 3

1( ) (1 3 ) ( )

2 F udW pdp p E E dpG Vc

5 41 2 2 2

3 7(1 3 )2

Re

ud F

f m cV G

h

2

( 1)2

1 3A

exp

N NA

N N

PfAAc

vexp

ObservablesLifetime Correlation ACorrelation BCorrelation CCorrelation aCorrelation DCorrelation RBeta SpectrumProton SpectrumPolarized SpectraBeta Helicity

Electron

Proton

Neutrino

Neutron Spin

A

B

C

5 41 2 2 2

3 7(1 3 )2ud

Re

F

fV

mG

ch


the Neutron

3-quark System: uddBeta-decay d u eFlux 1.2 x 1015 cm-2 s-1

cold neutronsultra cold neutrons


Hot topic questions beyond the SM

What do we learn from Vud and quark mixing?What is the origin of P-violation?

T-violation?

Additional forcesNumber of quark generationsNeutrino helicitySearch for RHC: W-mass and mixing

CP-violation


Neutrons at the SNS


Neutron Production at the ILL


Particle Physics: SM Tests

3D Neutron Tomography

Gravitation and Bound Quantum States


Neutron Production


1.1 A Measurement of Correlation A

• A new beam: decay rate 1 MHz/mThe ‘ballistic’ super-mirror cold-neutron guide H113H. Haese et al., Nucl. Instr. Meth. A485, 453 (2002)

• New Polarizers (TU Munich, ILL, HD)

• New Geometry for Beam polarization

A perfectly polarized neutron beam

•Signal to Background > 1000 : 1

• A new beam: decay rate 1 MHz/mThe ‘ballistic’ super-mirror cold-neutron guide H113H. Haese et al., Nucl. Instr. Meth. A485, 453 (2002)

• New Polarizers (TU Munich, ILL, HD)

• New Geometry for Beam polarization

A perfectly polarized neutron beam

•Signal to Background > 1000 : 1


The Experimental Setup at PF1B

M. Schumann 2006M. Schumann 2006


1.2 Tools


Polarizer

Spin up: reflectedSpin down: absorbed

Coherent nuclear (strong) and electronic (magnetic) scattering

Scattering probability:

resulting polarization:

2

nucl magW a a

nucl maga a1W W

PW W

UUFF

xx

100 neV100 neV

Hartmut Abele, University of Heidelberg 17T. Soldner, A. Petoukhov, V. Nesvizhevsky, M. Kreuz


The new Polarizer

Munich, ILL, HDA new geometry for Beam polarization A perfectly polarized neutron beam

Status 2002

Status 2004

98 %98 %

100 %100 %

96 %96 %

100 %100 %

90 %90 %

95 %95 %

94 %94 %

96 %96 %

T. Soldner, A. Petoukhov, V. Nesvizhevsky, M. Kreuz


Tools

Fermipotential: - Matter 100 neV

Neutron guidesWavelength filterPolarizer/AnalyzerUCN- perfect mirror

- neutron bottlesSubstrat (Glas)

Nickel

NickelTitan

Titan

2d sin=n

d

UUFF

xx

100 neV100 neV


The new Polarizer

Munich, ILL, HDA new geometry for Beam polarization A perfectly polarized neutron beam

Status 2002

Status 2004

98 %98 %

100 %100 %

96 %96 %

100 %100 %

90 %90 %

95 %95 %

94 %94 %

96 %96 %


Rf Spin flipper

Lab frame

Rotating frame

Rotating frame


The Instrument


1.3 Coefficient A: Spectrometer Perkeo II

to beamstopto beamstop

precise electron spectroscopyprecise electron spectroscopy

Electron

Neutron Spin


up: down:

NN

NNAexp

AN N

N Nexp


Principle:2x2- Detectiontwo hemispheresbackscattering suppressionlow backgroundstrong beam PF1:- count ratesystematic

Spectrometer Perkeo IIoben: unten:

NN

NNAexp

AN N

N Nexp

zum beamstopzum beamstop

precise electron spectroscopyprecise electron spectroscopy

2

( 1)2

1 3A

v

cexpA A Pf

= gA/gV


Results

Spectra Dissertation D. Mund, 2006


Result

Asymmetry A

Dissertation D. Mund, 2006


Beamrelated Background

Collimation system < 0.15 s-1

Det. 0

Det. 1

Fitregion

Electron-Spectrum

Beamline BG


2002 2002 2006 2006 correction uncertainty correction uncertainty polarization 1.1 % 0.3 % 0.3 % 0.1 % flipper efficiency 0.3 % 0.1 % 0.0 % 0.1 % Statistical error 0.45 % 0.26 % background 0.5 % 0.25 % 0.1 % 0.1 % detector function 0.26 % 0.1 % edge effect -0.24 % 0.1 % -0.22 % 0.05 % time resolution 0.25 % mirror effect 0.09 % 0.02 % 0.11 % 0.01 % backscattering 0.2 % 0.17% 0.003 % 0.001 % rad. corrections 0.09 % 0.05 % 0.09 % 0.05 % Sum 2.04 % 0.66 % 0.38 % 0.33 %

sum 2006 preliminary

2002 2002 2006 2006 correction uncertainty correction uncertainty polarization 1.1 % 0.3 % 0.3 % 0.1 % flipper efficiency 0.3 % 0.1 % 0.0 % 0.1 % Statistical error 0.45 % 0.26 % background 0.5 % 0.25 % 0.1 % 0.1 % detector function 0.26 % 0.1 % edge effect -0.24 % 0.1 % -0.22 % 0.05 % time resolution 0.25 % mirror effect 0.09 % 0.02 % 0.11 % 0.01 % backscattering 0.2 % 0.17% 0.003 % 0.001 % rad. corrections 0.09 % 0.05 % 0.09 % 0.05 % Sum 2.04 % 0.66 % 0.38 % 0.33 %

sum 2006 preliminary 2002: result: A = -0.1189(8) = -

1.2739(19)2006: result: A = -0.11948(40) = -1.2754(11)


Collaboration PERKEOII 1995 - 2006

ILL GrenobleJ. Last, U. Mayerhofer, O. Zimmer, V. Nesvizhevsky, T. Soldner, A. Petoukhov

Universität Heidelberg Stefan Baeßler, C. Raven, T. Müller, C. Metz, M. Astruc Hoffmann, Uta Peschke, Jürgen Reich, Bernhard Brand, Michael Kreuz, Ulrich Mayer Daniela Mund, Christian Plonka, Christian Vogel, Bastian Märkisch, Markus Brehm, Jochen Krempel, Marc Deissenroth, Marc Schumann, Alexander Kaplan, Daniel Wilkin, Dirk Dubbers, H.A.

U. MainzS. Baeßler

FZKF. Glück



Recommended value for lambda

= -1.27500.0009


1.4 A and

A as a function of gA and gV

Time reversal invariance, phase 180°ve = c, v = c,

see Lecture at Black Board



Thesis Doehner 1991




• Solar cycle p p D e+ e

p p e D e

…

• Neutron star formation p e n e

•Primordial element formation n e+ p e'

p e n e

n p e e'

•Neutrino detectors p e' n e+

•Neutrino forward-scattering e p e+ n etc.

•W, Z-production p p' W e e' etc.

• Solar cycle p p D e+ e

p p e D e

…

• Neutron star formation p e n e

•Primordial element formation n e+ p e'

p e n e

n p e e'

•Neutrino detectors p e' n e+

•Neutrino forward-scattering e p e+ n etc.

•W, Z-production p p' W e e' etc.

PROCESSES WITH SAME FEYNMAN DIAGRAM:

= gA/gV= gA/gV

Documents

Hartmut Abele Knoxville, 8 June 2006 Neutron Decay Correlation Experiments