Bounds on Time Reversal Violation From Polarized Neutron Capture With Unpolarized Targets

Area of Science:

• Nuclear Physics
• Particle Physics
• Fundamental Symmetries

Background:

• Parity violation in nuclear interactions is well-established.
• Time-reversal symmetry is a cornerstone of fundamental physics.
• Previous studies suggested the presence of parity-odd, time-reversal noninvariant interactions.

Purpose of the Study:

• To analyze constraints on parity-odd, time-reversal noninvariant interactions.
• To investigate the energy dependence of parity-violating polarized neutron capture.
• To address the challenge of distinguishing T-odd signatures from competing T-even effects.

Main Methods:

• Analysis of energy dependence in polarized neutron capture cross-sections.
• Theoretical estimation of competing T-even contributions.
• Identification of experimental strategies to enhance T-odd signatures.

Main Results:

• Confirmed the presence of a perturbation in energy dependence due to a parity (P)-odd, time (T)-odd interaction.
• Quantified the magnitude of competing T-even terms that can obscure the T-odd signal.
• Identified that these T-even terms can mask the T-odd signature.

Conclusions:

• The study provides constraints on parity-odd, time-reversal noninvariant interactions.
• Experimental strategies are proposed to overcome the masking effect of T-even terms.
• Further experiments are suggested for a more definitive search for T-odd interactions.