Currently, physicists working in High Energy Physics experiments have to write their queries in general purpose programming languages using complex frameworks for accessing the data. This distracts them from their actual work, namely data analysis, and reduces their productivity significantly. We have improved this situation by designing and implementing the first visual query language specific to this domain. Our goal was to provide a tool enabling physicists to formulate queries in their own terms and notation.

In this paper we focus on the formal definition of our visual query language (including syntax and semantics). The meanings of our operators are well-defined by means of translational semantics; i.e., we map all elements of our language to a well-known NF2 algebra. We conclude with a discussion of the advantages of this formal design approach.