Simple Science

Cutting edge science explained simply

# Physics# High Energy Physics - Experiment# High Energy Physics - Phenomenology

A Fresh Approach to New Physics Research

Scientists adopt a model-agnostic framework to uncover new physics signals.

― 6 min read


New Physics SearchNew Physics SearchReinventedfor new physics.A model-agnostic method enhances search
Table of Contents

Particle physics studies the smallest building blocks of matter and their interactions. The current framework for understanding these particles is called the Standard Model (SM). While the SM has explained many phenomena, scientists believe it is not complete. There are several unanswered questions, such as the nature of dark matter, the mass of neutrinos, and the imbalance between matter and antimatter in the universe. These questions lead scientists to look for New Physics (NP) beyond the SM, which could provide answers.

The Need for Model-Agnostic Searches

For decades, researchers have searched for NP with specific models in mind. However, no clear evidence has emerged for particles or interactions predicted by these models. This lack of results suggests that a broader approach might be effective. Instead of focusing solely on specific theories, scientists can explore the data from experiments without a predetermined model. By identifying unexpected patterns or differences in Data Samples, researchers might uncover signs of NP.

The Role of Machine Learning

Machine learning (ML) has gained prominence in various fields, including particle physics. ML tools are helpful for analyzing complex datasets and can efficiently identify patterns that might indicate NP. For example, using neural networks, researchers can fit data samples and test for differences between them. This approach allows scientists to probe the data more deeply than traditional methods.

Traditional Approaches in Particle Physics

Historically, searches for NP involved careful setups and hypotheses based on specific theories. Scientists would design experiments targeting particular particles or interactions predicted by their models. However, many of these experiments have yet to yield definitive results. Therefore, there is a need to consider alternative strategies and utilize modern techniques.

Symmetry in Particle Physics

In particle physics, Symmetries play an important role in defining how particles interact. The SM is based on symmetrical principles, which means that certain properties should appear equal under specific transformations. If Asymmetries or violations of these symmetries are detected in experimental data, this could be a strong indicator of NP. Therefore, examining the differences between data samples that are expected to behave symmetrically is crucial for identifying potential NP.

The New Testing Procedure

To search for these symmetry violations, researchers can develop a systematic approach that considers two data samples. The goal is to determine whether these samples were drawn from the same underlying distribution, as expected under the SM, or if they diverge, hinting at NP. This procedure involves constructing statistical tests that compare the two samples and test their compatibility.

The Importance of Data Size

One aspect that complicates the search for NP is the size of the samples being studied. In many traditional methods, researchers have relied on one sample being much larger than the other. This configuration often helps mitigate statistical fluctuations and provides a more reliable comparison. However, this technique may not work well when looking for small differences, as smaller samples can still yield valuable information.

Exploring the New Framework

Scientists developed a new framework that tackles the issues faced by traditional methods. This new approach treats both samples equally, allowing for a more balanced analysis. By using all available data rather than a single reference sample, researchers can examine potential asymmetries more effectively.

Testing For Asymmetries

The main idea behind this new framework is to examine whether two samples are compatible with the SM's symmetrical expectations or if they reveal discrepancies that could indicate NP. The new method employs statistical tests based on likelihood ratios, allowing researchers to calculate how likely it is that the observed data reflects the SM's predictions.

The Structure of the Framework

At the heart of this framework lies the concept of combining the data from both samples to form a comprehensive view. By treating all data as part of the same analysis, researchers can derive accurate estimates for the underlying distributions of both samples. This strategy enhances the ability to identify small deviations that may point to NP.

Implementing Machine Learning in the New Framework

This new framework greatly benefits from using machine learning techniques. Neural networks (NN) can effectively fit the data and model the underlying distributions. By training these networks on the data, researchers can gain insights into the differences between samples and how they might relate to NP.

Performance Evaluation of the Framework

Researchers have conducted various tests to evaluate the effectiveness of the new method. By simulating different scenarios and analyzing the results, they can assess how well the framework performs in detecting asymmetries and identifying potential NP.

Results from Simulated Data

The new method demonstrated promising results when applied to simulated datasets. In both symmetric scenarios (where both samples are drawn from the same distribution) and asymmetric scenarios (where one sample has NP signals), the framework performed well in differentiating between the two cases.

For symmetric cases, the framework produced results consistent with expected outcomes. In the asymmetric cases, the method was able to detect signals of NP, showing its effectiveness at identifying small but significant deviations from the SM predictions.

Comparing against Traditional Methods

When assessed against traditional methods, the new approach showcased its versatility. Unlike earlier techniques that required strict conditions regarding sample size, the new framework can operate efficiently even when comparing samples of similar sizes. This flexibility eliminates many limitations present in traditional searches and enables broader exploration of NP possibilities.

Practical Applications of the Framework

The application of this framework is particularly relevant in high-energy particle physics experiments, such as those conducted at the Large Hadron Collider (LHC). As researchers continue to collect vast amounts of data, the ability to analyze differences and search for NP without being constrained by specific models is vital.

Future Directions for Research

As this new method continues to develop, future research will focus on refining the framework's algorithms and expanding its capabilities. Researchers hope to enhance its sensitivity further and explore other observable quantities that could reveal NP.

Addressing Systematic Uncertainties

An important consideration in particle physics is the impact of systematic uncertainties. These uncertainties can arise from various sources during data collection and analysis, potentially masking the signals researchers aim to detect. The new framework strives to account for these uncertainties, ensuring that the conclusions drawn from the data are robust and reliable.

Final Thoughts

Particle physics is a dynamic field, constantly evolving as new data and techniques emerge. The introduction of this new framework represents a significant step forward in the search for NP. By leveraging modern technology, researchers can uncover new insights and push the boundaries of our understanding of the universe.

Conclusion

The exploration of NP is fundamental to advancing our understanding of the universe. By adopting innovative approaches, such as the new model-agnostic framework, researchers can better analyze complex datasets and identify potential signals that may have previously gone unnoticed. The future of particle physics looks promising, with the potential for groundbreaking discoveries on the horizon.

Original Source

Title: Learning New Physics from Data -- a Symmetrized Approach

Abstract: Thousands of person-years have been invested in searches for New Physics (NP), the majority of them motivated by theoretical considerations. Yet, no evidence of beyond the Standard Model (BSM) physics has been found. This suggests that model-agnostic searches might be an important key to explore NP, and help discover unexpected phenomena which can inspire future theoretical developments. A possible strategy for such searches is identifying asymmetries between data samples that are expected to be symmetric within the Standard Model (SM). We propose exploiting neural networks (NNs) to quickly fit and statistically test the differences between two samples. Our method is based on an earlier work, originally designed for inferring the deviations of an observed dataset from that of a much larger reference dataset. We present a symmetric formalism, generalizing the original one; avoiding fine-tuning of the NN parameters and any constraints on the relative sizes of the samples. Our formalism could be used to detect small symmetry violations, extending the discovery potential of current and future particle physics experiments.

Authors: Shikma Bressler, Inbar Savoray, Yuval Zurgil

Last Update: 2024-10-18 00:00:00

Language: English

Source URL: https://arxiv.org/abs/2401.09530

Source PDF: https://arxiv.org/pdf/2401.09530

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.

Similar Articles