[Paper Review] Les Houches 2017: Physics at TeV Colliders New Physics Working Group Report

G. Brooijmans, Matthew J. Dolan+81 more|arXiv (Cornell University)|Mar 27, 2018

Distributed and Parallel Computing Systems2 references104 citations

TL;DR

The report surveys LHC new physics search strategies, focusing on two-body resonances, heavy boson decays to vector-like quarks, LLPs, Higgs sector explorations, and recasting tools for result reinterpretation.

ABSTRACT

We present the activities of the `New Physics' working group for the `Physics at TeV Colliders' workshop (Les Houches, France, 5--23 June, 2017). Our report includes new physics studies connected with the Higgs boson and its properties, direct search strategies, reinterpretation of the LHC results in the building of viable models and new computational tool developments.

Motivation & Objective

• Motivate and organize the exploration of new physics scenarios relevant to TeV-scale colliders.
• Categorize heavy resonance production and decay channels, including decays to vector-like quarks and non-SM final states.
• Assess Higgs sector extensions and EFT approaches for probing BSM effects at the LHC and future colliders.
• Discuss data interpretation, recasting challenges, and the development of computational tools for NP studies.

Proposed method

• Classify heavy resonances by their SM quantum numbers and production mechanisms (scalar and vector cases).
• Identify allowed decays to SM quarks plus vector-like quarks and map resulting final states.
• Review EFT approaches and STXS strategies to access BSM effects in Higgs physics and diboson processes.
• Evaluate the impact of non-SM decay channels on resonance search reach and reinterpretation of LHC results.
• Summarize recasting methodology, including cross-checks between public tools and recommendations for reporting analysis details.

Experimental results

Research questions

• RQ1 What heavy resonances can be singly produced in proton-proton collisions and how do their SM quantum numbers constrain production and decay?
• RQ2 Which final states arising from heavy resonances decaying to SM quarks and vector-like quarks are currently covered by LHC searches, and which are uncovered?
• RQ3 How do non-SM decay channels affect the sensitivity of heavy resonance searches and the bounds on new states?
• RQ4 How effective are current recasting tools and reporting practices for interpreting LHC results in broader NP scenarios?
• RQ5 What EFT bases and Higgs-sector extensions provide the strongest coverage for BSM effects at current and future colliders?

Key findings

• A systematic categorization of two-body resonant searches reveals several uncovered channels that could motivate new analyses (e.g., certain leptoquark and excited fermion final states).
• Decays of heavy bosons into vector-like quarks can significantly alter search strategies and the interpretation of resonance bounds.
• NLO QCD effects can meaningfully impact single production rates and kinematic distributions for vector-like quarks, affecting signal discrimination.
• Long-lived particle searches and freeze-in dark matter scenarios connect LLP lifetimes to cosmological relic abundance, highlighting lifetime as a key measurement target.
• Recasting studies show that detailed object reconstruction efficiencies and cut flows are essential for reliable reinterpretations across models, with recommendations for analysis reporting to aid recasting.