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Electroweak Corrections: Insights Beyond the Standard Model

A dive into the significance of electroweak corrections in particle physics.

Hesham El Faham, Ken Mimasu, Davide Pagani, Claudio Severi, Eleni Vryonidou, Marco Zaro

― 7 min read


Electroweak Corrections Electroweak Corrections Explained interactions and predictions. Exploring the impact on particle
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The Standard Model of particle physics is kind of like the ultimate recipe book for the universe. It describes the fundamental particles and forces that make up everything around us, from the tiniest atoms to the largest galaxies. But like any good recipe, it has its limits and sometimes needs a bit of tweaking. Enter the Standard Model Effective Field Theory (SMEFT), which is like adding a dash of spice to enhance the flavor of the original recipe.

The SMEFT aims to account for potential new physics that isn't included in the Standard Model. Think of it as an upgrade that lets scientists explore what's beyond our current understanding. This theory systematically incorporates additional features, such as higher-dimensional Operators, while still adhering to the rules that the Standard Model lays out.

Electroweak Corrections: The Importance of Precision

In the realm of particle physics, "electroweak" refers to the unification of two fundamental forces: electromagnetism and the weak nuclear force. Electroweak corrections become significantly important at high energy levels, especially as we push towards tera-electronvolt scales. This is where things get spicy-thanks to Sudakov logarithms, which are like those tiny surprises that pop up in a recipe and change everything.

These corrections help improve the accuracy of predictions coming from the Standard Model. High-energy collisions at particle colliders, like the Large Hadron Collider, can create conditions that allow electroweak corrections to shine. The SMEFT framework encourages the inclusion of electroweak corrections in both Standard Model predictions and analyses conducted in the SMEFT.

A Closer Look at the SMEFT Operators

Within SMEFT, we find a set of tools called operators. These operators represent various ways particles can interact with each other beyond the basic interactions described by the Standard Model. The operators of interest in this discussion are dimension-six four-fermion operators, which allow for contact interactions among fermions (the building blocks of matter).

In simpler terms, these operators tell scientists how particles behave when they collide at high energies. By computing the effects of these operators in relevant processes like top-quark pair production and the Drell-Yan process, researchers can gain insights into the potential presence of new particles or forces.

The Role of Sudakov Logarithms

Sudakov logarithms are like those unexpected flavor bursts in a dish that take it to the next level. At high energies, these logarithms can become quite large and significantly affect scattering processes. They provide corrections that scientists must take into account to refine their calculations and ensure they're on point with their predictions.

In practice, the presence of these Sudakov logarithms describes the strength of the electroweak corrections. When plugged into the calculations, they can show how the interactions differ from what one would typically expect, challenging scientists to rethink their assumptions and measurements.

The Quest for Precision

So, why is all this important? Well, precision is key in particle physics. The more accurate the theories and predictions, the better scientists can understand the workings of the universe. Efforts to enhance the precision include adopting advanced computational techniques to extract high-order corrections in the SMEFT framework.

Researchers have worked hard to ensure that both the Standard Model and SMEFT predictions stand up to scrutiny-especially since experimental data from colliders can be quite the reality check. With every new discovery-or lack thereof-scientists are forced to refine their models and predictions.

The Phenomenological Studies

After laying down the theoretical foundation, researchers turn their attention to practical implications. This involves conducting phenomenological studies to investigate how well the SMEFT holds up compared to the Standard Model in the context of specific processes.

By examining processes like top-quark pair production at colliders, researchers can gather valuable data. In these experiments, the goal is to ascertain how the electroweak corrections affect the outcomes of collisions. The results not only further our understanding of particle interactions but may also shine a light on any discrepancies or surprises that hint at new physics.

Using Monte Carlo Simulations

To get a clearer picture of complex processes, scientists often rely on Monte Carlo simulations. Think of these simulations as a virtual kitchen where researchers can mix and match ingredients to see what happens. Monte Carlo methods allow for the generation of numerous event scenarios, painting a comprehensive picture of how different parameters can affect the results.

By simulating various scenarios, researchers can gain a better understanding of the likelihood and range of outcomes. This process is incredibly useful in determining the potential effects of different SMEFT operators and electroweak corrections on particle interactions.

The Challenge of Mass Suppression

As exciting as it is to explore the effects of higher-dimensional operators and electroweak corrections, certain challenges come into play. One such challenge is mass suppression. This phenomenon occurs when certain interactions are less likely to happen because they involve heavier particles, making them vanish under specific conditions.

The challenge for scientists is to identify which processes are affected by mass suppression and how that affects their predictions. By focusing on specific cases, researchers can better gauge the implications of mass-suppressed amplitudes and how they contrast with non-suppressed interactions.

Addressing Flat Directions

In the world of particle physics, flat directions are like roads less traveled. They represent combinations of parameters that don't change the results of calculations much, leading to a sort of stagnation in determining the underlying physics at play.

When studying these flat directions in the SMEFT context, the inclusion of higher-order corrections can prove beneficial. By providing more data points and insights, researchers can lift these flat directions, opening up new avenues for exploration. This, in turn, allows for a more robust understanding of the underlying physics, aiding in the search for new phenomena and interactions.

The Fisher Information Matrix

Now, let's introduce the Fisher Information Matrix (FIM)-the unsung hero of parameter sensitivity analysis. Simply put, the FIM helps researchers quantify how sensitive various distributions are to changes in their parameters. In the context of SMEFT, it serves as a valuable tool for assessing how well specific Wilson coefficients can be constrained based on the available data.

By diagonalizing the FIM, scientists can identify independent directions in parameter space. These directions represent combinations of Wilson coefficients that can be constrained by measurements, providing insight into how experimental data can be utilized to inform theoretical models. Eagles may soar, but scientists dive deep into parameter space!

Conclusion: The Journey Ahead

As we conclude our exploration of electroweak corrections within the SMEFT framework, it's evident that the quest for understanding particle physics is a multi-faceted journey. From the importance of precision to the challenges of mass suppression and flat directions, every twist and turn leads to newfound insights and discoveries.

Through innovative computational techniques, phenomenological studies, and careful analysis of experimental data, researchers strive to refine their models and predictions. As we push the boundaries of our understanding, the potential for new physics lurking just beyond our current knowledge keeps the scientific community buzzing.

So, whether you're a seasoned physicist or just someone intrigued by the mysteries of the universe, the story of electroweak corrections in the SMEFT is an engaging one. Who knows? Maybe one day, we’ll discover new particles hiding in the corners of the universe, just waiting for the right recipe to bring them into the light!

Original Source

Title: Electroweak corrections in the SMEFT: four-fermion operators at high energies

Abstract: In the Standard Model (SM), electroweak (EW) corrections become significant at high energies, particularly at the tera-electronvolt scale and beyond, due to the presence of Sudakov logarithms. At these energy scales, the Standard Model Effective Field Theory (SMEFT) framework provides an enhanced sensitivity to potential new physics effects. This motivates the inclusion of EW corrections not only for SM predictions but also for analyses within SMEFT. In this work, we compute EW corrections in the high-energy limit for a selected set of dimension-six operators, specifically the class of four-fermion contact interactions, in key hard-scattering processes relevant to both current and future colliders: top-quark pair production at the Large Hadron Collider (LHC) and in a muon collider scenario, as well as the Drell-Yan process at the LHC. We first discuss the technical details and challenges associated with evaluating EW Sudakov logarithms in SMEFT, contrasting them with the SM case. We then present phenomenological results for the aforementioned processes, highlighting the non-trivial effects introduced by EW corrections arising from the insertion of dimension-six, four-fermion operators. Importantly, the resulting $K$-factors exhibit significant deviations from their SM counterparts, with dependencies not only on the process but also on the specific operators considered. Finally, we explore the potential to lift flat directions in the SMEFT parameter space by incorporating higher-order corrections, using Fisher information techniques.

Authors: Hesham El Faham, Ken Mimasu, Davide Pagani, Claudio Severi, Eleni Vryonidou, Marco Zaro

Last Update: Dec 20, 2024

Language: English

Source URL: https://arxiv.org/abs/2412.16076

Source PDF: https://arxiv.org/pdf/2412.16076

Licence: https://creativecommons.org/licenses/by/4.0/

Changes: This summary was created with assistance from AI and may have inaccuracies. For accurate information, please refer to the original source documents linked here.

Thank you to arxiv for use of its open access interoperability.

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