Cancellation of divergences in unitary gauge calculation of H→γγH \to \gamma \gamma process via one W loop, and application

Following the thread of R. Gastmans, S. L. Wu and T. T. Wu, the calculation in the unitary gauge for the $H \to \gamma \gamma$ process via one W loop is repeated, without the specific choice of the independent integrated loop momentum at the beginning. We start from the 'original' definition of each Feynman diagram, and show that the 4-momentum conservation and the Ward identity of the W-W-photon vertex can guarantee the cancellation of all terms among the Feynman diagrams which are to be integrated to give divergences higher than logarithmic. The remaining terms are to the most logarithmically divergent, hence is independent from the set of integrated loop momentum. This way of doing calculation is applied to $H \to \gamma Z$ process via one W loop in the unitary gauge, the divergences proportional to $M_Z^2/M^3$ including quadratic ones are all cancelled, and terms proportional to $M_Z^2/M^3$ are shown to be zero. The way of dealing with the quadratic divergences proportional to $M_Z^2/M^3$ in $H \to \gamma Z$ has subtle implication on the employment on the Feynman rules especially when those rules can lead to high level divergences. So calculation without integration on all the $\delta$ functions until have to is a more proper or maybe necessary way of the employment of the Feynman rules.Comment: 1 figure, 34 pages (updated

Criteria for identifying failure optimization algorithms in building energy optimization and case studies

Optimization algorithms plays a vital role in the Building Energy Optimization (BEO) technique. Although many algorithms are currently used in BEO, it is difficult to find an algorithm that performs well for all optimization problems. Some algorithms may fail in some cases. This study specifically focuses on failure algorithms in BEO and the possible causes. Several criteria are proposed for identifying failure algorithms. Four optimization problems base d on the DOE small and large office buildings are developed. Three commonly used algorithms in BEO, namely, Pattern Search (PS ) algorithm, Genetic Algorithm (GA ) and Particle Swarm Optimization (PSO) algorithm, are applied to the four problems to investigate possible rea sons for their failure. Results indicate that the effectiveness of the three selected algorithms is highly dependent on the optimization problems to be addressed. Besides, the control parameter setting of the PS algorithm appears to be a significant factor that may cause the algorithm to lose effectiveness. However, it does not seem to be the main reason for the failure of the GA and PSO algorithm. In General, the results gained from this study can deepen our understanding of optimization algorithms used in BEO. Besides, understanding the reasons why optimization algorithms are ineffective can help architects, engineers, and consultants select the appropriate optimization algorithms and set their parameters to achieve a better BEO design that is less vulnerable to failure

UNDERSTANDING CONSUMER TRUST IN SOCIAL COMMERCE WEBSITES

The social commerce represents a new form of electronic commerce mediated by social networking sites. It provides companies with competitive tools for online promotion, and it also assists consumers to make better-informed purchasing decisions based on the sharing of experiences from other consumers. Trust is important in social commerce environment as it serves as a foundation for consumers to evaluate product information from companies as well as from other consumers. However, extant literature still lacks clear understanding of the nature of trust in social commerce. This study sets out to understand trust development in social commerce websites. Specifically, based on trust transference theory, we develop a research model to examine how consumer trust in social commerce impacts their trust in the company and their electronic word of mouth intention. In addition, we also examine how customers’ prior transaction experience with a company could impact their social commerce trust development and serve as a mediator in the trust transfer process. The research model is empirically examined using a survey method consisting of 375 users of a social commerce website. This study contributes to the conceptual and empirical understanding of trust in social commerce. The academic and practical implications of this study are also discussed