Chiral Logarithms in ΔS=1\Delta S=1 Kaon Decay Amplitudes in General Effective Flavor Theories

We study the chiral logarithms in $\Delta S=1$ kaon decay amplitudes from new flavor physics in beyond-standard-model theories. We systematically classify the chiral structures of dimension-5, 6 and 7 effective QCD operators constructed out of light-quark (up, down and strange) and gluon fields. Using the standard chiral perturbation theory, we calculate the leading chiral-logarithms associated with these operators. The result is useful for lattice calculations of the QCD matrix elements in $K\to \pi\pi$ decay necessary, for example, to understand the physical origin of the direct CP violation parameter $\epsilon'$. As a concrete example, we consider the new operators present in minimal left-right symmetric models

New constructions of MDS codes with complementary duals

Linear complementary-dual (LCD for short) codes are linear codes that intersect with their duals trivially. LCD codes have been used in certain communication systems. It is recently found that LCD codes can be applied in cryptography. This application of LCD codes renewed the interest in the construction of LCD codes having a large minimum distance. MDS codes are optimal in the sense that the minimum distance cannot be improved for given length and code size. Constructing LCD MDS codes is thus of significance in theory and practice. Recently, Jin (\cite{Jin}, IEEE Trans. Inf. Theory, 2016) constructed several classes of LCD MDS codes through generalized Reed-Solomon codes. In this paper, a different approach is proposed to obtain new LCD MDS codes from generalized Reed-Solomon codes. Consequently, new code constructions are provided and certain previously known results in \cite{Jin} are extended

Three new classes of optimal frequency-hopping sequence sets

The study of frequency-hopping sequences (FHSs) has been focused on the establishment of theoretical bounds for the parameters of FHSs as well as on the construction of optimal FHSs with respect to the bounds. Peng and Fan (2004) derived two lower bounds on the maximum nontrivial Hamming correlation of an FHS set, which is an important indicator in measuring the performance of an FHS set employed in practice. In this paper, we obtain two main results. We study the construction of new optimal frequency-hopping sequence sets by using cyclic codes over finite fields. Let $\mathcal{C}$ be a cyclic code of length $n$ over a finite field $\mathbb{F}_q$ such that $\mathcal{C}$ contains the one-dimensional subcode $\mathcal{C}_0=\{(\alpha,\alpha,\cdots,\alpha)\in \mathbb{F}_q^n\,|\,\alpha\in \mathbb{F}_q\}.$ Two codewords of $\mathcal{C}$ are said to be equivalent if one can be obtained from the other through applying the cyclic shift a certain number of times. We present a necessary and sufficient condition under which the equivalence class of any codeword in $\mathcal{C}\setminus\mathcal{C}_0$ has size $n$. This result addresses an open question raised by Ding {\it et al.} in \cite{Ding09}. As a consequence, three new classes of optimal FHS sets with respect to the Singleton bound are obtained, some of which are also optimal with respect to the Peng-Fan bound at the same time. We also show that the two Peng-Fan bounds are, in fact, identical.Comment: to appear in Designs, Codes and Cryptograph

The progenitors of type Ia supernovae in the semidetached binaries with red giant donors

Context. The companions of the exploding carbon-oxygen white dwarfs (CO WDs) for producing type Ia supernovae (SNe Ia) are still not conclusively confirmed. A red-giant (RG) star has been suggested to be the mass donor of the exploding WD, named as the symbiotic channel. However, previous studies on the this channel gave a relatively low rate of SNe Ia. Aims. We aim to systematically investigate the parameter space, Galactic rates and delay time distributions of SNe Ia from the symbiotic channel by employing a revised mass-transfer prescription. Methods. We adopted an integrated mass-transfer prescription to calculate the mass-transfer process from a RG star onto the WD. In this prescription, the mass-transfer rate varies with the local material states. Results. We evolved a large number of WD+RG systems, and found that the parameter space of WD+RG systems for producing SNe Ia is significantly enlarged. This channel could produce SNe Ia with intermediate and old ages, contributing to at most 5% of all SNe Ia in the Galaxy. Our model increases the SN Ia rate from this channel by a factor of 5. We suggest that the symbiotic systems RS Oph and T CrB are strong candidates for the progenitors of SNe Ia.Comment: 8 pages, 6 figure

Performance of an Infrared Photoacoustic Single Gas Analyzer in Measuring Ammonia from Poultry Houses

A single-gas photoacoustic analyzer, Chillgard RT, was evaluated for its performance of measuring ammonia (NH3) concentrations in poultry production under laboratory and field conditions, using a multi-gas photoacoustic analyzer, INNOVA 1412, as a reference method. Calibration gases were used to evaluate the cross-interferences of carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4), and water vapor on NH3 measurements by Chillgard RT. The response times of Chillgard RT and INNOVA were measured in the laboratory using four vessels containing broiler litter. Side-by-side field comparisons between the Chillgard RT and INNOVA were conducted on a laying-hen farm and a broiler farm over two five-month periods. A strong linear relationship existed between the Chillgard RT and INNOVA NH3readings. The NH3 measurement by the Chillgard RT showed no effect by CO2, N2O, CH4, or water vapor under typical operational conditions in poultry operations. The Chillgard RT demonstrated a faster response to NH3 than the INNOVA. Following 120-s measurements, the Chillgard RT and INNOVA achieved 99.6% and 96.7% of the expected values, respectively, when the INNOVA was configured at a 30-s sampling interval. The INNOVA response time was positively affected by water vapor level in the air samples. The Chillgard RT overestimated NH3 concentrations by 3.24%, 10%, and 22.9% for laying-hen houses, stored boiler litter, and broiler houses, respectively, as compared to the INNOVA. Thus, performance of the Chillgard RT should be carefully validated before used in field NH3 measurements