Parity violation of electroweak force in phase transitions of single crystals of d- and L-alanine and valine.
Three kinds of experiments have been designed in attempting to observe theparity violation of electroweak force at the phase transition of singlecrystals of D- and L-alanine and valine.(1) An obvious λ phasetransition at 270 ± 1 K was shown in the specific heat measurement ofalanine and valine enantiomers by differential scanning calorimetry. Thebiologically dominant L-enantiomer was found to have lower energy. (2)Magnetization of single crystals of D- and L-alanine and D-valine weremeasured as a function of temperature using the SQUID magnetometer. Thedifference of the mass susceptibility χ(ρ) ∼ T curve between theD-alanine and L-alanine is attributable to the variation of intramoleculargeometry of chirality density, which is related to the parity violationenergy shift of a chiral molecule and is a consequence of the short rangeof the weak interaction between the nuclei and electrons. (3) Laser Ramanspectra of D- and L-alanine at different low temperatures (100 K, 250 K,260 K, 270 K, 280 K and 290 K) showed that the second order Cα-Hdeformation modes at 2606 cm(-1), 2724 cm(-1) of D-alanine vanishedat 270 K but reappeared at 100 K. In the same method, L-alanine has nosuch phenomenon. An obvious decrease in the scattering intensity of themethyne group C(α)-H stretching mode at 2964 cm(-1) in D-alanineoccurs at the λ transition temperature. We present our experimentsinvolving the possible relevance of Z(0) force with Salam's putativephase transition in the origin of homochirality.
Department of Technical Physics, Peking University, Beijing, 100871 China.
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Wang
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Yi
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Ni
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Zhao
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Jin
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Tang
D- and L-alanine and valine; parity violation of Z0 force; phase transition