parity violation in hadronic systems christopher crawford, university of kentucky 38 th symposium of...

Parity Violationin Hadronic Systems

Christopher Crawford, University of Kentucky38th Symposium of Nuclear Physics

Cocoyoc, Mexico 2015-01-07

38th Symposium on Nuclear Physics

Outline• Hadronic Parity Violation

– Hadronic Weak Interaction (HWI) formalism

• NPDGamma Experiment– Setup, preliminary results

• n-3He Experiment– Setup, status update

Madison Spencer

2015-01-07 2/33


Hadronic Weak Interaction in a nutshell

Hadronic

Nuclear

EW

<nuclear structure>

<QCD structure>

Nuclear PV

Few-body PV

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DDH Potential

isos

pin

rang

e

Desplanques, Donoghue, Holstein, Annals of Physics 124, 449 (1980)

N N

N N

Meson exchang

e

STRONG(PC)

WEAK(PV)

PV meson exchange

2015-01-07

np A nD A n3He Ap np n pp Az p Az

fp-0.11 0.92 -0.18 -3.12 -0.97 -0.34

hr0 -0.50 -0.14 -0. 23 -0.32 0.08 0.14

hr1 -0.001 0.10 0.027 0.11 0.08 0.05

hr2 0.05 0.0012 -0.25 0.03

h0 -0.16 -0.13 -0. 23 -0.22 -0.07 0.06

h1 -0.003 -0.002 0.05 0.22 0.07 0.06

Adelberger, Haxton, A.R.N.P.S. 35, 501 (1985)

4/33


Danilov parameters / EFT• Elastic NN scattering

at low energy (<40 MeV) S-P transition (PV)

S=1/2+1/2 , I=1/2+1/2 Antisymmetric in L, S, I

Conservation of J • Equivalent to Effective

Field Theory (EFT) in low energy limit

C.-P. Liu, PRC 75, 065501 (2007)

2015-01-07 5/33


p-p and nuclei Anapole

Existing HPV data• p-p scat. 15, 45 MeV Az

pp

• p- scat. 46 MeV Azpp

• p-p scat. 220 MeV Azpp

• n+pd+ circ. pol. Pd

• n+pd+ asym. Ad

• n- spin rot. dn/dz

• 18F asym. I =1• 19F, 41K, 175Lu, 181Ta asym.• 21Ne (even-odd)• 133Cs, 205Tl anapole moment

GOAL – resolve couplingconstants from few-bodyPV experiments onlyWasem, Phys. Rev. C 85 (2012) 022501 1st Lattice QCD result

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NPDGamma CollaborationR. Alarcon1, R. Allen18, L.P. Alonzi3, E. Askanazi3, S. Baeßler3, S. Balascuta1, L. Barron-Palos2, A. Barzilov27, W. Berry8, C. Blessinger18, D. Blythe1, D. Bowman4, M. Bychkov3, J. Calarco ,R. Carlini5, W. Chen6, T. Chupp7, C. Crawford8, M. Dabaghyan9, A. Danagoulian10, M. Dawkins11, D. Evans3, J. Favela2, N. Fomin12, W. Fox11, E. Frlez3, S. Freedman13, J. Fry11, C. Fu11, C. Garcia2, T. Gentile6, M. Gericke14 C. Gillis11, K Grammer12, G. Greene4,12, J Hamblen26, C. Hayes12, F. Hersman9, T. Ino15, E. Iverson4, G. Jones16, K. Latiful8, K. Kraycraft8, S. Kucuker12, B. Lauss17, Y. Li30, W. Lee18, M. Leuschner11, W. Losowski11, R. Mahurin12, M. Maldonado-Velazquez2, E. Martin8, Y. Masuda15, M. McCrea14, J. Mei11, G. Mitchell19, S. Muto15, H. Nann11, I. Novikov25, S. Page14, D. Parsons26, S. Penttila4, D. Pocinic3, D. Ramsay14,20, A. Salas-Bacci3, S. Santra21, S. Schroeder3, P.-N. Seo22, E. Sharapov23, M. Sharma7, T. Smith24, W. Snow11, J. Stuart26, Z. Tang11, J. Thomison18, T. Tong18, J. Vanderwerp11, S. Waldecker26, W. Wilburn10, W. Xu30, V. Yuan10, Y. Zhang29

1Arizona State University2Universidad Nacional Autonoma de Mexico

3University of Virginia 4Oak Ridge National Laboratory

5Thomas Jefferson National Laboratory6National Institute of Standards and

Technology7Univeristy of Michigan, Ann Arbor

8University of Kentucky9University of New Hampshire

10Los Alamos National Laboratory11Indiana University

12University of Tennessee, Knoxville13University of California at Berkeley

14University of Manitoba, Canada

23Joint Institute of Nuclear Research, Dubna, Russia

24University of Dayton25Western Kentucky University

26University of Tennessee at Chattanooga27Univeristy of Nevada at Los Vegas

28University of California, Davis29Lanzhou University

30Shanghai Institute of Applied Physics

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15High Energy Accelerator Research Organization (KEK), Japan

16Hamilton College17Paul Scherer Institute, Switzerland

18Spallation Neutron Source, ORNL19University of California at Davis

20TRIUMF, Canada21Bhabha Atomic Research Center, India

22Duke University


Experimental Layout

Supermirror Polarizer Gamma DetectorsLH2 TargetRF Spin RotatorBeam Monitors

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Spallation neutron source spallation sources: LANL, SNS

• pulsed -> TOF -> energy LH2 moderator: cold neutrons

• thermal equilibrium in ~30 interactions

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Neutron Flux at the SNS FnPB

SNS TOF window

15 m

eV L

H2

thre

shol

d

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Flux = 6.5x1010 n/s/MW 2.5 Å < λ < 6.0 Å


Chopped & folded spectrum

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FnPB supermirror polarizer T=25.8% transmissionP=95.3% polarizationN=2.2£1010 n/s output flux (chopped)

simulations using McStas / ROOT ntuple

S. Balascuta et al., Nucl. Instr. Meth. A671 137 (2012)2015-01-07 12/33


Longitudinal RF spin rotator• Resonant RF spin rotator,

– 1/t RF amplitude tuned to velocity of neutrons– Affects spin only – NOT velocity! (no static gradients)

• essential to reduce instrumental systematics– danger: must isolate RF field from the detector– false asymmetries: additive & multiplicave

holding field

sn

BRF

P. Neo-Seo, et al. Phys. Rev. ST Accel. Beams 11 084701 (2008)

2015-01-07 13/33


16L liquid para-hydrogen target

15 m

eV

ortho

para

capture

En (meV)

(b

)

30 cm long 1 interaction length 99.97% para 1% depolarization Improvements: pressure-stamped vessel

thinner windows

p p

para-H2

p p

ortho-H2

E = 15 meV

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Ortho vs. Para H2 neutron scattering

L. Barron-Palos et al., Nucl. Instr. Meth. A671 137 (2012)

Simulation byKyle Grammer

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CsI(Tl) Detector Array 4 rings of 12 detectors each

• 15 x 15 x 15 cm3 each VPD’s insensitive to B field detection efficiency: 95% current-mode operation

• 5 x 107 gammas/pulse• counting statistics limited

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Background Sub. & Geometry Factors

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UP-DOWN LEFT-RIGHT

neutronpol.

RFSFeff.

targetdepol.

Aluminumbackground

Aluminumasymmetry


Recent Hydrogen Data• Shown: 200 hr. data from Fall 2012• Completed full data set June 2014

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• Preliminary result (~10% dataset) AUD = (-7.14 ± 4.4) x 10-8

ALR = (-0.91 ± 4.3) x 10-8

• Full results to be announced soon δA approximately 13 ppb


Systematic & Statistical Uncertainties

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n-3He CollaborationR. Alarcon1, S. Baeßler3, S. Balascuta1, L. Barron-Palos2, A. Barzilov7, D. Bowman4, J. Calarco9, V. Cianciolo4, C. Crawford5, J. Favela2, N. Fomin4,13, I. Garishvili13, M. Gericke6, C. Gillis8, G. Greene4,13, V. Gudkov11, J. Hamblen12, C. Hayes13, E. Iverson4, K. Latiful5, S. Kucuker13, M. Maldonado-Velazquez2, M. McCrea6, I. Novikov15, C. Olguin6, S. Penttila4, E. Plemons12, A. Ramirez2, P.-N. Seo14, Y. Song11, A. Sprow5, J. Thomison4, T. Tong4, M. Viviani10, C. Wichersham12

1Arizona State University2Universidad Nacional Autonoma de Mexico

3University of Virginia 4Oak Ridge National Laboratory

5University of Kentucky6University of Manitoba, Canada

7Univeristy of Nevada at Los Vegas8Indiana University

9University of New Hampshire10Instituto Nazionale di Fisica Nucleare,

Sezione di Pisa11University of South Carolina

12University of Tennessee at Chattanooga13University of Tennessee, Knoxville

14Duke University15Western Kentucky University

2015-01-07 22/33


n-3He Reaction

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n + n p pn pn +p n p

np~ kn very small for low-energy neutrons

- essentially the same asym.- must discriminate between back-to-back proton-triton

S(I):

4He J =0+ resonance

sensitive to EFT couplingor DDH couplings

~10% I=1 contribution(Gerry Hale, qualitative)

A ~ -1–3x10-7 (M. Viviani, PISA)

A ~ -1–4x10-7 (Gudkov)mixing between 0+, 0- resonance

Naïve scaling of p-p scattering at 22.5 MeV: A ~ 5x10-8

PV observables:

19.81520.578

Tilley, Weller, Hale, Nucl. Phys. A541, 1 (1992)


10 Gausssolenoid

RF spinrotator

3He target /ion chamber

supermirrorbender polarizer

(transverse)

FnPB coldneutron guide

3He BeamMonitor

FNPB n-3He

Experimental setup

• longitudinal holding field – suppressed PC nuclear asymmetry A=1.7x10-6 (Hales) sn kn x kp suppressed by two small angles

• RF spin flipper – negligible spin-dependence of neutron velocity• 3He ion chamber – both target and detector

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Solenoid • Definition of σndirection

– Adiabatic rotation from transverse to longitudinal spin

– 10 mG, 0.1% uniformity Univ. Nacional Autónoma de México

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Transverse RF Spin Rotator• Double-cosine-theta coil

– Fringeless transverse RF field– Longitudinal OR transverse– Designed using scalar potential

Univ. Kentucky / Univ. Tennessee

2015-01-07 26/27


Collimator / Beam scanner• Tune the beam size/axis for longitudinal/transverse asymmetryU. Tennessee, UNAM, Arizona State U.

2015-01-07 27/27


Active Target / Ion Chamber• 3He for both target and ionization gas

– Macor frames with 9 x 16 sense wires, 8 x 17 HV wires– All aluminum chamber except for knife edges– 12” x 0.9 mm CF aluminum windows – 16 mCi tritium over life of experiment

University of Manitoba

2015-01-07 28/27


Readout Electronics• Ionization read out in current mode

– 144 channels read out simultaneously– Low-noise preamplifiers mount on chamber– 24-bit 100 kHz simultaneous sampling digitizers

Oak Ridge National Lab, Univ. Kentucky, Univ. Tennessee

2015-01-07 29/27


Commissioning data• Instr. asymmetry, Beam scan, RFSF tune, Ion chamber tune

– Completed Dec. 2014; ready to take beam 5000 hr., Feb-Dec 2015

2015-01-07 30/27

Ainstr = (2.6 ± 1.6) x 10-10 in single chanel

upstream Polarized neutron spatial profile downstream

Ionization current in each cell

Asymmetry Measurement – Statistics

• PV physics asymmetry– Extracted from weighted average

of single-wire spin asymmetries– Sensitivities calculated by MC

• 15% measurement in 1 beam cycle

N = 1.5x1010 n/s x 107 s (116 days) P = 96.2% neutron polarization d = 6 detector inefficiency


Systematic Uncertainties• Beam fluctuations, polarization, RFSF efficiency:• knr ~ 10-5 small for cold neutrons• PC asymmetries minimized with longitudinal polarization• Alignment of field, beam, and chamber to 10 mrad is achievable• Unlike n p –> d ° or n d –> t °,

n-3He is very insensitive to gammas (only Compton electrons)

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Conclusion• Hadronic Parity Violation

– Is a complementary probe ofnuclear and nucleonic structure

– Need 4 experiments to isolate spin and isospin dependence

– With pp (45MeV), pp (220 MeV), NPDGamma, n-3He, NSR-IIIwe can test the self-consistency of HWI formalisms

• NPDGamma Experiment– Sensitive to long-range coupling f¼

– Results to be released soon• n-3He Experiment

– 15% projected uncertainty: most accurate few-body HWI experiment

– FnPB beam: June 2014 – Dec 2015

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Thank you!

parity violation in hadronic systems christopher crawford, university of kentucky 38 th symposium of...

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