HEPData Search

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Proton polarization in deuteron photodisintegration in the Δ(1232)-resonance region

Zybalov, A.A. ; Konovalov, O.G. ; Marekhin, S.V. ; et al.

Nucl.Phys.A 533 (1991) 642-650, 1991.

Inspire Record 1392876 DOI 10.17182/hepdata.36724

We report the results from measurements of proton polarization P , in the γ +D→p+n reaction at photon energies ranging from 200 to 350 MeV. The data obtained are compared with the measured analysing power A , of the reverse reaction and with model calculations. The assumption of the dominant contribution of isobar configurations in this region is on the whole confirmed by the present proton polarization measurements.

5 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Polarization of protons in the reactions $\gamma^{3,4}$He$\rightarrow\overrightarrow{p}X$ and the quasideuteron model

Zybalov, A.A. ; Karasev, S.P. ; Konovalov, O.G. ; et al.

Sov.J.Nucl.Phys. 47 (1988) 955-956, 1988.

Inspire Record 1392524 DOI 10.17182/hepdata.17410

None

1 data table

Table 1

No description provided.

Polarization in the quasielastic scattering of 1-GeV/c protons on light nuclei.

Miklukho, O.V. ; Aleshin, N.P. ; Belostotsky, S.L. ; et al.

Phys.Atom.Nucl. 63 (2000) 824-833, 2000.

Inspire Record 533009 DOI 10.17182/hepdata.31238

Polarization measurements in the A(p, 2p)B reactions on 6Li, 7Li, and 28Si nuclei at a proton-beam energy of 1 GeV were performed in a kinematically complete experiment. By using a two-arm magnetic spectrometer, two secondary protons were recorded in coincidence at asymmetric scattering angles of θ1=15°−26° and θ2=58.6° for residual-nucleus momenta in the range K B=0–150 MeV/c. Either arm of the spectrometer was equipped with polarimeters based on proportional chambers. The data coming from this experiment are analyzed within the distorted-wave impulse approximation. It is shown that the polarization of recoil protons formed at angle θ2 in the interaction featuring a proton from the P shell of the 7Li nucleus can be described under the assumption of an effective intranuclear-proton polarization by using the single-particle shell-model wave function of the nucleus. Our data on the polarizations of the two protons from the reaction (p, 2p) on a 28Si nucleus also suggest the effective polarization of the protons in the D shell of the 28Si nucleus. It is found that, for high recoil-nucleus momenta of K B≥90 MeV/c, the effective polarization of the protons in the P shell of the 6Li nucleus—this polarization was discovered in studying the polarization of recoil protons in the reaction 6Li(p, 2p)5He—cannot be described within the shell model assuming LS coupling. As might have been expected, the polarization of recoil protons knocked out from the S shells of the 6Li and 7Li nuclei comply well with the predictions obtained in the impulse approximation with allowance for the depolarization effect alone.

37 data tables

Table 1

REACTION WITH THE LI6 P-SHELL PROTON.

Table 2

REACTION WITH THE LI6 P-SHELL PROTON.

Table 3

REACTION WITH THE LI6 P-SHELL PROTON.

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Measurements of the tau polarization in Z0 decays

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.

Z.Phys.C 67 (1995) 183-202, 1995.

Inspire Record 393793 DOI 10.17182/hepdata.47961

A sample of Z0→τ+τ− events observed in the DELPHI detector at LEP in 1991 and 1992 is analysed to measure the τ polarisation in the exclusive decay channels$ev\bar v$,$\mu v\bar v$, πν, ρν and a1ν. The τ polarisation is also measured with an inclusive hadronic analysis which benefits from a higher efficiency and a better systematic precision than the use of the exclusive decay modes. The results have been combined with those published on the 1990 data. A measurement of the τ polarisation as a function of production angle yields the values for the mean τ polarisation 〈P〉τ=−0.148±0.022 and for the Z0 polarisationPZ=−0.136±0.027. These results are used to determine the ratio of vector to axial-vector effective couplings for taus$\bar v_\tau/\bar a_\tau= 0.074 \pm 0.011$, and for electrons$\bar v_e /\bar a_e= 0.068 \pm 0.014$, compatible with e-τ universality. With the assumption of lepton universality, the ratio of vector to axial-vector effective couplings for leptons$\bar v_l /\bar a_l= 0.072 \pm 0.008$ is obtained, implying a value of the effective weak mixing angle sin2θefflept=0.2320±0.0021.

10 data tables

Table 1

Results are for both TAU+ and TAU- decay.

Table 2

The systematic error contains a systematic error of 0.003 common to all channels.

Table 3

Errors are statistical only.