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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
38th Symposium on Nuclear Physics
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
38th Symposium on Nuclear Physics
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)
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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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38th Symposium on Nuclear Physics
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
2015-01-07 7/33
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
38th Symposium on Nuclear Physics
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
38th Symposium on Nuclear Physics
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
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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)
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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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38th Symposium on Nuclear Physics
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
38th Symposium on Nuclear Physics
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
38th Symposium on Nuclear Physics
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
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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)
38th Symposium on Nuclear Physics
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
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Collimator / Beam scanner• Tune the beam size/axis for longitudinal/transverse asymmetryU. Tennessee, UNAM, Arizona State U.
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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
38th Symposium on Nuclear Physics
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
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38th Symposium on Nuclear Physics
Commissioning data• Instr. asymmetry, Beam scan, RFSF tune, Ion chamber tune
– Completed Dec. 2014; ready to take beam 5000 hr., Feb-Dec 2015
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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
38th Symposium on Nuclear Physics
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!
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