Readiness of CMS Simulation towards LHC Startup

CMS experiment has used detector simulation software in its conceptual as well as technical design. With the detector construction near its completion, the role of simulation has changed toward understanding collision data to be collected by CMS in near future. CMS simulation software is becoming a data driven, realistic and accurate Monte Carlo programme. The software architecture is described with some detail of the framework as well as detector specific components. Performance issues are discussed as well

Data Driven Approach to Calorimeter Simulation in CMS

CMS is looking forward to tune detector simulation using the forthcoming collision data from the LHC. CMS established a task force in February 2008 in order to understand and reconcile the discrepancies observed between the CMS calorimetry simulation and the test beam data recorded during 2004 and 2006. Within this framework, significant effort has been made to develop a strategy of tuning fast and flexible parameterizations describing showering in the calorimeter with available data from test beams. These parameterizations can be used within the context of Full as well as Fast Simulation. The study is extended to evaluate the use of first LHC collision data, when it becomes available, to rapidly tune the CMS calorimeter

Data driven approach to calorimeter simulation in CMS

CMS is looking forward to tune detector simulation using the forthcoming collision data from the LHC. CMS established a task force in February 2008 in order to understand and reconcile the discrepancies observed between the CMS calorimetry simulation and the test beam data recorded during 2004 and 2006. Within this framework, significant effort has been made to develop a strategy of tuning fast and flexible parameterizations describing showering in the calorimeter with available data from test beams. These parameterizations can be used within the context of Full as well as Fast Simulation. The study is extended to evaluate the use of first LHC collision data, when it becomes available, to rapidly tune the CMS calorimeter

Puzzles of excited charm meson masses

We attempt a comprehensive analysis of the low lying charm meson states which present several puzzles, including the poor determination of masses of several non-strange excited mesons. We use the well-determined masses of the ground states and the strange first excited states to `predict' the mass of the non-strange first excited state in the framework of heavy hadron chiral perturbation theory, an approach that is complementary to the well-known analysis of Mehen and Springer. This approach points to values for the masses of these states that are smaller than the experimental determinations. We provide a critical assessment of these mass measurements and point out the need for new experimental information.Comment: 9 pages, 1 figure, accepted for publication in Physics Letters

Investigating the Health of a Rice Field Ecosystem Using Thermodynamic Extremal Principles

This study investigates the dynamic behaviour of a rice field ecosystem and aims to define its integral features using the stability concept of an ecological goal function. This function is based on the extremal principles of thermodynamics, which assume that certain energetic processes of ecosystems—such as the rate of exergy destruction—are directed by the self-organizing informatics of the systems towards maxima or minima.  In our study, we exploit the availability of substantially long time-series data relating to a rice field ecosystem to gain an evocative understanding of its growth trajectory in light of the thermodynamic principles. We accomplished this by constructing a model based on the STELLA 9.0 software and calculating the extremal values of growth rates (storage) and those of exergy destruction and entropy creation. The results showed that the values of both maximum dissipation and maximum exergy progressed apace with that of maximum storage till the maturation of rice and became stable thereafter, whereas maximum residence time and maximum specific dissipation values initially decreased before their asymptotic rise. A similar pattern was also observed for the maximum specific exergy. However, the maximum power dissipation curve followed a highly fluctuated course before becoming stable on the maturation of rice

Detector Simulation Challenges for Future Accelerator Experiments

Detector simulation is a key component for studies on prospective future high-energy colliders, the design, optimization, testing and operation of particle physics experiments, and the analysis of the data collected to perform physics measurements. This review starts from the current state of the art technology applied to detector simulation in high-energy physics and elaborates on the evolution of software tools developed to address the challenges posed by future accelerator programs beyond the HL-LHC era, into the 2030–2050 period. New accelerator, detector, and computing technologies set the stage for an exercise in how detector simulation will serve the needs of the high-energy physics programs of the mid 21st century, and its potential impact on other research domains