关键词: 对称性破缺, 手性起源, β电子极化, Salam假说

Abstract: The first unifying principle in biochemistry is that the key moleculcs-amino acids, sugars have the same handedness or chirality. Chiral molecules and their corresponding mirror images may be defined by left (L)or right (D) optical rotatory dispersion. All living systems translate their genes into proteins composed of 20 L-amino acids (except glycine). Like proteins, the nucleic acids DNA and RNA exist in nature in only one chirality composed of D configuration of 2-deoxyribose and ribose monomers. This phenomenon occurs when molecules are asymmetric. The cause for the great preference in life for L-amino acids and D-sugars over their corresponding enantiomers has been extensively studied. Based on a series of experiments of our research, it is found that elementary particles interact differentially with enantiomers of amino acids. The difference, though very small, could be detected by sensitive methods when the system is far from equilibrium at low temperature (77K) but it could not cause macroscopic excess of one particular enantiomer without an effective amplification mechanism. Based on Salam's hypothesis, studies show that an obvious lambda transition at (270±1)K occurred while measuring the specific heat of D and L-valine and alanine by differential scanning calorimetry (DSC) in the temperature region of 77-300K, with the C_p values of D form greater than that of L form. Magnetization measurement of single crystals of D, L-alanine and D-valine on SQUID magnetometer show that magnetic transition temperature coincident with that of lambda transition. Temperature dependence of the X ray powder diffraction for D-valine showed no crystal lattice change under the temperature cooling down from 293K to 123 K. We propose that the difference of the magnetic susceptibility X-T curve between D and L-forms of alanine and valine attributed to the variation of intramolecular geometry of chiral density in the presence of an external magnetic field. Such observations as magnetic susceptibility of molecules in single crystal amino acids is the first to be monitored.

Key words: asymmetry breaking, origin of homochirality, electron polarization, Salam hypothesis