A new experimental study of the circular polarization of np capture γ-rays

Knyaz’kov, V. A.; Kolomenskii, É.A.; Lobashov, V.M.; Nazarenko, V. A.; Pirozhkov, A. N.; Shablii, A.I.; Шульгина, Е. В.; Sobolev, Y.V.; Yegorov, A.I.

doi:10.1016/0375-9474(84)90505-0

Cited by 75 publications

(32 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The requirement of a high neutron flux and the difficulty of measuring the circular polarization of the outgoing photon make a measurement of P γ challenging. A previous experiment was able to put a bound on P γ which, however, is consistent with zero [11].…”

Section: Introductionmentioning

confidence: 81%

Energy dependence of the parity-violating asymmetry of circularly polarized photons indγ⃗→npin pionless effective field theory

Vanasse

Schindler

2014

Phys. Rev. C

View full text Add to dashboard Cite

We calculate the energy dependence of the asymmetry in the cross sections for circularly polarized photons on an unpolarized deuteron target in d γ → np in pionless effective field theory. By matching the parity-violating low-energy constants to different sets of corresponding model parameters we obtain estimates for the asymmetry. In addition we calculate a possible figure of merit for the asymmetry in order to assess the preferred photon energy at which to perform a possible future experiment at a high-intensity photon source. *

show abstract

Section: Introductionmentioning

confidence: 81%

Energy dependence of the parity-violating asymmetry of circularly polarized photons indγ⃗→npin pionless effective field theory

Vanasse

Schindler

2014

Phys. Rev. C

View full text Add to dashboard Cite

show abstract

“…in terms of C ( 3 S 1 − 1 P 1 ) is that an experimental limit exists on the induced circular polarization in unpolarized neutron capture, np → d γ [38,39], which also depends on C ( 3 S 1 − 1 P 1 ) . Imposing the large-N c results on the expression for this process [19] yields…”

Section: Application To Existing Measurementsmentioning

confidence: 99%

Large-Nclimit reduces the number of independent few-body parity-violating low-energy constants in pionless effective field theory

2016

View full text Add to dashboard Cite

The symmetries of the Standard Model dictate that for very low energies, where nucleon dynamics can be described in terms of a pionless effective field theory (EFT(/ π)), the leading-order parity-violating nucleon-nucleon Lagrangian contains five independent unknown low-energy constants (LECs). We find that imposing the approximate symmetry of QCD that appears when the number of colors N c becomes large reduces the number of independent LECs to two at leading order in the combined EFT(/ π) and large-N c expansions. We also find a relation between the two isoscalar LECs in the large-N c limit. This has important implications for the number of experiments and/or lattice calculations necessary to confirm this description of physics. In particular, we find that a future measurement of the PV asymmetry in γd → np together with the existing result for PV pp scattering would constrain all leading-order (in the combined expansion) LECs. This is considerably improved from the previous understanding of the system.

show abstract

“…In the %-K system, for example, definite effects have been observed only in p+ p scattering [3 -6]; measurements of PNC observables in the n+ p system [7,8] are not yet sensitive enough to provide useful constraints.…”

mentioning

confidence: 99%

Parity mixing of the0+-0−I=1 doublet in
Zeps
¹
,
Adelberger
²
,
Garcı́a
³

et al. 1995
Phys. Rev. C

View full text Add to dashboard Cite

We studied parity mixing of the 02, 0i; I=1 doublet in N (E 8.6 MeV) to probe the isoscalar component of the parity nonconserving (PNC) nucleon-nucleon interaction. The weak matrix element connecting the 0+ and 0 levels was determined by measuring the longitudinal analyzing power (AL, ) over the narrow 1 = 0+ C(p, p) resonance at E"=1.16 MeV. Scattered protons were detected in two arrays of four scintillators arranged symmetrically about the beam axis at mean angles of Oq --35' and 02 --155'. The PNC signal was the difFerence in the longitudinal analyzing power observed at the two angles. Feedback loops were used to stabilize the position, angle, and spin direction of the beam on target. The observed signal was Ar, (02) -Ar, (O&) = 0.9+0.6 x 10 which corresponds to a weak matrix element (H, k) = 0.38 + 0.28 eV. Our measured (H, k) disagrees with theoretical expectations; recent shell-model calculations by Horoi et at. using the PNC NN amplitudes of Desplanques, Donoghue, and Holstein yield (H, k)'s that lie in the range from -0.2 eV to -0.8 eV. We briefly discuss some theoretical uncertainties that arise because the structure of the N doublet diAers in important ways from other known parity doublets. In ancillary studies of the C(p, p) reaction at 0~= 90', we found that the excitation energies and widths of

show abstract

A new experimental study of the circular polarization of np capture γ-rays

Cited by 75 publications

References 15 publications

Energy dependence of the parity-violating asymmetry of circularly polarized photons indγ⃗→npin pionless effective field theory

Energy dependence of the parity-violating asymmetry of circularly polarized photons indγ⃗→npin pionless effective field theory

Large-Nclimit reduces the number of independent few-body parity-violating low-energy constants in pionless effective field theory

Parity mixing of the0+-0−I=1 doublet in
Zeps
¹
,
Adelberger
²
,
Garcı́a
³

et al. 1995
Phys. Rev. C

Contact Info

Product

Resources

About

A new experimental study of the circular polarization of np capture γ-rays

Cited by 75 publications

References 15 publications

Energy dependence of the parity-violating asymmetry of circularly polarized photons indγ⃗→npin pionless effective field theory

Energy dependence of the parity-violating asymmetry of circularly polarized photons indγ⃗→npin pionless effective field theory

Large-Nclimit reduces the number of independent few-body parity-violating low-energy constants in pionless effective field theory

Parity mixing of the0+-0−I=1 doublet inZeps1, Adelberger2, Garcı́a3 et al. 1995Phys. Rev. C

Contact Info

Product

Resources

About

Parity mixing of the0+-0−I=1 doublet in
Zeps
¹
,
Adelberger
²
,
Garcı́a
³

et al. 1995
Phys. Rev. C