A minimal U(1)′U(1)^\prime extension of MSSM in light of the B decay anomaly

Motivated by the $R_K$ and $R_{K^*}$ anomalies from B decays, we extend the minimal supersymmetric model with a non-universal anomaly-free $U(1)^\prime$ gauge symmetry, coupling non-universally to the lepton sector as well as the quark sector. In particular, only the third generation quarks are charged under this $U(1)^\prime$, which can easily evade the dilepton bound from the LHC searches. An extra singlet is introduced to break this $U(1)^\prime$ symmetry allowing for the $\mu$-term to be generated dynamically. The relevant constraints of $B_s-\bar{B}_s$ mixing, $D^0-\bar{D}^0$ mixing and the LHC dilepton searches are considered. We find that in the allowed parameter space this $U(1)^\prime$ gauge interaction can accommodate the $R_K$ and $R_{K^*}$ anomalies and weaken considerably the $Z^\prime$ mass limits while remaining perturbative up to the Planck scale.Comment: 12 pages,2 figure

Stability of Phase-modulated Quantum Key Distribution System

Phase drift and random fluctuation of interference visibility in double unbalanced M-Z QKD system are observed and distinguished. It has been found that the interference visibilities are influenced deeply by the disturbance of transmission fiber. Theory analysis shows that the fluctuation is derived from the envioronmental disturbance on polarization characteristic of fiber, especially including transmission fiber. Finally, stability conditions of one-way anti-disturbed M-Z QKD system are given out, which provides a theoretical guide in pragmatic anti-disturbed QKD.Comment: 9 pages, 3 figue

Intrinsic-Stabilization Uni-Directional Quantum Key Distribution Between Beijing and Tianjin

Quantum key distribution provides unconditional security for communication. Unfortunately, current experiment schemes are not suitable for long-distance fiber transmission because of instability or backscattering. We present a uni-directional intrinsic-stabilization scheme that is based on Michelson-Faraday interferometers, in which reflectors are replaced with 90 degree Faraday mirrors. With the scheme, key exchange from Beijing to Tianjin over 125 kilometers with an average error rate is below 6% has been achieved and its limited distance exceeds 150 kilometers. Experimental result shows the system is insensitive to environment and can run over day and night without any break even in the noise workshop.Comment: 7 pages,4 figure

2-Chloro­methyl-1-methyl-1,3-benzimidazole

The title compound, C9H9ClN2, was prepared from the reaction of N-methyl­benzene-1,2-diamine and 2-chloro­acetic acid in boiling 6 M hydro­chloric acid. The benzimidazole unit is approximately planar, the largest deviation from the mean plane being 0.008 (1) Å. The Cl atom is displaced by 1.667 (2) Å from this plane. The methyl group is statistically disordered with equal occupancy

2-Amino-4-(2-chloro­phen­yl)-7,7-di­methyl-5-oxo-5,6,7,8-tetra­hydro-4H-chromene-3-carbonitrile hemihydrate

The asymmetric unit of the title compound, C18H17ClN2O2·0.5H2O, contains two organic mol­ecules and one solvent water mol­ecule. In each organic mol­ecule, the cyclo­hexene ring adopts an envelope conformation with the C atom connecting the two methyl groups on the flap; the 4H-pyran ring is nearly planar [maximum deviation = 0.113 (3) Å in one mol­ecule and 0.089 (3) Å in the other mol­ecule] and is approximately perpendicular to the chloro­phenyl ring [dihedral angle = 86.43 (15)° in one mol­ecule and 89.73 (15)° in the other mol­ecule]. Inter­molecular N—H⋯N, N—H⋯O, O—H⋯O and O—H⋯Cl hydrogen bonding is present in the crystal