Measurement of Transverse Polarization of Electrons Emitted in Free Neutron Decay

Abstract

The final analysis of the experiment determining both components of the transverse polarization of electrons (${\sigma }_{T_1}$, ${\sigma }_{T_2}$) emitted in the $\beta$-decay of polarized, free neutrons is presented. The T-odd, P-odd correlation coefficient quantifying ${\sigma }_{T_2}$, perpendicular to the neutron polarization and electron momentum, was found to be $R=$ 0.004$\pm 0.012\pm$0.005. This value is consistent with time reversal invariance, and significantly improves both earlier result and limits on the relative strength of imaginary scalar couplings in the weak interaction. The value obtained for the correlation coefficient associated with ${\sigma }_{T_1}$, $N=$ 0.067$\pm 0.011\pm$0.004, agrees with the Standard Model expectation, providing an important sensitivity test of the experimental setup. The present result sets constraints on the imaginary part of scalar and tensor couplings in weak interaction. Implications for parameters of the leptoquark exchange model and minimal supersymmetric model (MSSM) with R-parity violation are discussed.

References in corpus (7)

• An Improved Experimental Limit on the Electric Dipole Moment of the Neutron
• Improved limit on the permanent electric dipole moment of 199Hg
• Tests of the standard electroweak model in beta decay
• Evidence for an anomalous like-sign dimuon charge asymmetry
• Search for CP-violation in Positronium Decay
• Measurement of the Transverse Polarization of Electrons Emitted in Free Neutron Decay
• R-parity violating supersymmetric contributions to the neutron beta decay

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