Higgs boson was discovered at the Large Hadron Collider located at the border between Switzerland and France, which delivered the most important theoretical validation underlying the basis for the funding and construction of the collider itself. Fitting in at the 125 GeV (eV: electronvolt) void in the Standard Model for Particle Physics, the search for the particle led to a successive number of colliders of increasingly higher energy to be built over the years.
The discovery of the long sought after particle highlights the important role that theory and simulation help guide experimental efforts. In particular, it laid the path towards the resolution of a conundrum, and in the case of the Higgs boson, provided the key parameter for its measurement success: its energy level. Why is the energy parameter so important? Because without it, particle physicists would be searching blindly for the elusive particle with colliders of the wrong beams and energy.
In general, there are two important adjustable parameters of large colliders: (i) the types of beams that they collide, which determine the kind of subparticles released and the type of new physics discoverable, and (ii) the maximum energy level attainable by the collider. In the case of the Large Hadron Collider, its design specifies an energy level significantly higher than previous colliders. Measuring at 13 terraelectronvolts, the Large Hadron Collider possesses sufficient capacity to discover new physics after its initial success at discovering the Higgs boson during operations at a lower energy level.
As planners decide whether to build the next generation particle collider at the International Linear Collider, which has an estimated cost of US $10 billion, theory and its verification through simulation again play an important role in providing the tentative and preliminary evidence that justify the building of a large experiment machine involving an international consortium of particle and theoretical physicists. Based on the best available and latest science, this is one way where theory and simulation help lay the case for decision making by policy makers, who need to use public money from each participating country to fund the international effort aimed at understanding the deeper realms of physics not ventured into by man before.
As in other areas of science, the quality of science reported by theorists and experts in simulation holds the key to whether a collider would be built. From another perspective, if the decision is based on, for example, over-optimistic predictions of the probability that a specific particle would be detected by envisioned detection mechanisms, large amount of public money would be wasted on an experiment machine unable to fulfil its design aims. Theory, simulation, and experiment are the triumvirate in modern science, and each is important in its own way and which informs the others in an iterative scientific process.
In summary, theoretical predictions form the keystone for large physics experiments to verify the predictions and uncover new physics in the process. Accurate predictions would go a long way in helping experimentalists chart an experiment path to the identification of a new particle or phenomenon while understanding the mechanistic underpinnings of the process. However, overestimates or inaccurate predictions may void an expensive collider before its operation as its energy range may not encompass the energy of the sought after particle; thereby, wasting large amount of public money from countries around the world used in funding the design and building of the collider.
Interested readers may want to read one of my related preprint on “What drove computational chemistry forward: theory or experiment?” available at PeerJ Preprints, Link