Les Houches 2015: Physics at TeV Colliders Standard Model Working Group Report (1605.04692v1)

Abstract: This Report summarizes the proceedings of the 2015 Les Houches workshop on Physics at TeV Colliders. Session 1 dealt with (I) new developments relevant for high precision Standard Model calculations, (II) the new PDF4LHC parton distributions, (III) issues in the theoretical description of the production of Standard Model Higgs bosons and how to relate experimental measurements, (IV) a host of phenomenological studies essential for comparing LHC data from Run I with theoretical predictions and projections for future measurements in Run II, and (V) new developments in Monte Carlo event generators.

• The paper presents precision calculations, advancing NLO and N²LO methods to enhance predictions for Higgs production and related processes.
• It refines parton distribution functions with PDF4LHC15 and upgrades Monte Carlo generators to reduce uncertainties in collider event simulations.
• The report emphasizes accurate electroweak corrections and simplified cross-section techniques that strengthen the link between theory and LHC measurements.

Insights from the Les Houches 2015 Workshop on Physics at TeV Colliders

The Les Houches 2015 workshop, as documented in the "Physics at TeV Colliders" report, represents a concerted effort by the Standard Model working group to advance the precision and scope of theoretical and experimental particle physics at high energies, specifically in light of data from the Large Hadron Collider (LHC). The workshop brought together experts from various subfields and contexts, focusing on the development and application of next-to-leading-order (NLO) and next-to-next-to-leading-order (N$^2$LO) techniques, parton distribution functions, and other tools essential for accurately predicting and interpreting collider data.

Key Developments in Theoretical Calculations and Tools

1. Precision Calculations: A salient feature of the workshop was the advancement of high precision calculations with a special emphasis on N$^3$LO calculations in perturbative QCD for processes such as inclusive Higgs boson production. Differential predictions at N$^2$LO in QCD and automation for NLO electroweak corrections were notably refined.
2. PDFs and Monte Carlo Generators: Considerable efforts were allocated towards developing and refining parton distribution functions (PDFs), notably with the introduction of PDF4LHC15, which integrates improvements for cross-section predictions. Additionally, Monte Carlo tools saw enhancements in event generation and uncertainty management.
3. Higgs Physics and Simplified Cross Sections: The exploration of Higgs boson properties remained a focal point, specifically through simplified cross-section methodologies that bridge theoretical predictions and experimental observations, facilitating more accurate Higgs boson measurements and interpretation.
4. Electroweak Corrections and Extended Energy/Luminosity: As colliders operate at higher energies and luminosities, the necessity for precise electroweak (EW) corrections has become more prominent. The insights from these corrections are critical as they impact experimental measurements significantly and guide theoretical model refinements.

Phenomenological Investigations

The workshop included detailed phenomenological studies, addressing areas such as the tagging of quarks and gluons and defining a novel Les Houches variable—Les Houches Angularity—to improve data analysis. These efforts aim to align theoretical predictions closely with experimental data, thereby enhancing our understanding of fundamental particles and interactions at TeV scales.

Implications and Future Directions

The workshop outcomes provide significant implications for both practical experimental setups and the theoretical landscape. With the LHC continuing operations at 13 TeV, these developments lay the groundwork for analyzing high-statistics data with unprecedented precision. The evolution of Monte Carlo generators and advanced PDF sets will likely push the boundaries of current models, offering deeper insights into the Standard Model and potential new physics.

In future settings, emphasis on multi-leg processes and loop corrections might enhance the predictive power of simulations further. The continually evolving computational techniques and theoretical insights promise to refine our understandings considerably, potentially unravelling complexities within the Standard Model and beyond.

In conclusion, the proceedings from the Les Houches 2015 workshop encapsulate substantial progress across a range of technical areas vital for modern high-energy physics, setting a robust foundation for impending research initiatives and experimental investigations.