HepML, an XML-based format for describing simulated data in high energy physics

Abstract

In this paper we describe a HepML format and a corresponding C++ library developed for keeping complete description of parton level events in a unified and flexible form. HepML tags contain enough information to understand what kind of physics the simulated events describe and how the events have been prepared. A HepML block can be included into event files in the LHEF format. The structure of the HepML block is described by means of several XML Schemas. The Schemas define necessary information for the HepML block and how this information should be located within the block. The library libhepml is a C++ library intended for parsing and serialization of HepML tags, and representing the HepML block in computer memory. The library is an API for external software. For example, Matrix Element Monte Carlo event generators can use the library for preparing and writing a header of a LHEF file in the form of HepML tags. In turn, Showering and Hadronization event generators can parse the HepML header and get the information in the form of C++ classes. libhepml can be used in C++, C, and Fortran programs. All necessary parts of HepML have been prepared and we present the project to the HEP community.

LCG MCDB and HepML, next step to unified interfaces of Monte-Carlo Simulation

“…The main idea of these subsystems is to develop a set of routines for the collaboration software which would give a direct access to event files in LCG MCDB for the MC production on computing farms. In order to allow a possibility for automatic access to event sample description, MCDB team provides an API based on XML representation of event sample meta-data [12]. The current version of the API is developed as a C++ library, which can be added to collaboration software.…”

“…Keeping the metadata within event samples are extremely useful for correct processing, verifying and re-usage of the event samples. Now the only project proposed unified meta-data description and storage, is HepML [7,8,9].…”

Towards enhanced databases for High Energy Physics

“…This version was superseded by a more modern one, called HepData [3], developed within the CEDAR project [4], with the information reorganized according to the relational DBMS MySQL, in a complex structure of many tables with different kinds of relations (one-to-many, many-to-many). At that time, the HepML data format [5], based on XML, was created to enter data, as well as a web interface in Java for allowing user queries [6]. The parallel development of further tools, like e.g.…”

HepSim: A Repository with Predictions for High-Energy Physics Experiments

“…Among these tools, the closest repository that focuses on storing data with theoretical predictions is the MCDB Monte Carlo database developed within the CMS Collaboration. This publicly available repository mainly includes the CompHEP MC events [6] in the HepML format [7]. This paper discusses a public repository with Monte Carlo simulations (including NLO calculations) designed for fast calculation of cross sections or any kinematic dis-2 tribution.…”