Editing Particle physics (section)

== Theory ==
{{Quantum field theory|cTopic=Standard model}}
Theoretical particle physics attempts to develop the models, theoretical framework, and mathematical tools to understand current experiments and make predictions for future experiments (see also [[theoretical physics]]). There are several major interrelated efforts being made in theoretical particle physics today.

One important branch attempts to better understand the [[Standard Model]] and its tests. Theorists make quantitative predictions of observables at [[collider]] and [[Astroparticle physics|astronomical]] experiments, which along with experimental measurements is used to extract the parameters of the Standard Model with less uncertainty. This work probes the limits of the Standard Model and therefore expands scientific understanding of nature's building blocks. Those efforts are made challenging by the difficulty of calculating high precision quantities in [[quantum chromodynamics]]. Some theorists working in this area use the tools of perturbative [[quantum field theory]] and [[effective field theory]], referring to themselves as [[Particle physics phenomenology|phenomenologists]].{{Citation needed|date=September 2020}} Others make use of [[lattice field theory]] and call themselves ''lattice theorists''.

Another major effort is in model building where model builders develop ideas for what physics may lie [[beyond the Standard Model]] (at higher energies or smaller distances). This work is often motivated by the [[hierarchy problem]] and is constrained by existing experimental data.<ref>{{Cite web |last=Gagnon |first=Pauline |date=March 14, 2014 |title=Standard Model: a beautiful but flawed theory |url=http://www.quantumdiaries.org/2014/03/14/the-standard-model-a-beautiful-but-flawed-theory/ |access-date=September 7, 2023 |website=Quantum Diaries}}</ref><ref>{{Cite web |title=The Standard Model |url=https://home.cern/science/physics/standard-model |access-date=September 7, 2023 |website=CERN}}</ref> It may involve work on [[supersymmetry]], alternatives to the [[Higgs mechanism]], extra spatial dimensions (such as the [[Randall–Sundrum model]]s), [[Preon]] theory, combinations of these, or other ideas. [[Vanishing dimensions theory|Vanishing-dimensions theory]] is a particle physics theory suggesting that systems with higher energy have a smaller number of dimensions.<ref>{{cite web|url=http://atramateria.com/the-vanishing-dimensions-of-the-universe/|title=The vanishing dimensions of the Universe|date=March 22, 2011|publisher=Astra Materia|last1=Corbion|first1=Ashley|accessdate=May 21, 2013}}</ref>

A third major effort in theoretical particle physics is [[string theory]]. ''String theorists'' attempt to construct a unified description of [[quantum mechanics]] and [[general relativity]] by building a theory based on small strings, and [[brane]]s rather than particles. If the theory is successful, it may be considered a "[[Theory of Everything]]", or "TOE".<ref>{{Cite web |last=Wolchover |first=Natalie |date=2017-12-22 |title=The Best Explanation for Everything in the Universe |url=https://www.theatlantic.com/science/archive/2017/12/string-theory-everything/548774/ |access-date=2022-03-11 |website=The Atlantic |language=en |archive-date=15 November 2020 |archive-url=https://web.archive.org/web/20201115210213/https://www.theatlantic.com/science/archive/2017/12/string-theory-everything/548774/ |url-status=live }}</ref>

There are also other areas of work in theoretical particle physics ranging from [[Particle physics in cosmology|particle cosmology]] to [[loop quantum gravity]].{{Citation needed|date=September 2020}}