Search for new physics with ATLAS at the LHC

TL;DR

This paper surveys the ATLAS experiment's prospective reach for new physics at the LHC, focusing on the Higgs sector (SM and MSSM), supersymmetry, and a variety of other beyond-Standard Model scenarios. It details production mechanisms and decay channels, and outlines strategy and sensitivity estimates across luminosity scenarios, highlighting gluon fusion for the SM Higgs, H→γγ and multilepton/Z channels for discovery, and MSSM channels that cover large regions of parameter space. It also discusses SUSY discovery and the challenge of disentangling signals to measure sparticle masses via kinematic endpoints across SUGRA, GMSB, and R-parity-violating models, as well as probing technicolor, excited quarks, leptoquarks, compositeness, extra dimensions, and monopoles. Overall, the work articulates ATLAS's broad capabilities to discover or constrain TeV-scale new physics and informs experimental strategies for interpreting LHC data across a diverse set of theories.

Abstract

Due to the high energy and luminosity of the LHC, the ATLAS experiment has a huge discovery potential for new physics. A Standard Model Higgs boson can be discovered over the full range of allowed masses, and its mass should be measured with a precision of about 0.1%. The Higgs sector of the MSSM should be fully explored by searches for supersymmetric Higgs bosons. Squarks and gluinos can be discovered up to masses of 2.5 TeV and several precision measurements can be performed in the SUSY sector. The existence of particles predicted by other theories beyond the Standard Model has been also investigated.

Figures (4)

• Figure 1: ATLAS sensitivity for the discovery of a Standard Model Higgs boson. The statistical significances are plotted as a function of the Higgs mass for individual channels (different symbols), as well as for the combination of all channels (full line), assuming an integrated luminosity of 100 fb$^{-1}$.
• Figure 2: ATLAS sensitivity for the discovery of MSSM Higgs bosons. The $5\sigma$ discovery contour curves for individual channels are shown in the $(m_{\rm A},\,\tan\beta)$ plane for an integrated luminosity of 300 fb$^{-1}$.
• Figure 3: Mass distribution of two b-jets for SUGRA point: $m_0=100$ GeV, $m_{1/2}=300$ GeV, $\tan\beta=2.1$, $A_0=300$ GeV and ${\rm sgn}\mu=+1$. The ${\rm h\rightarrow b\bar{b}}$ signal (solid), the SUSY background (dashed) and the SM background (dotted) are shown.
• Figure 4: Dilepton distribution for SUGRA point: $m_0=800$ GeV, $m_{1/2}=200$ GeV, $\tan\beta=10$, $A_0=0$ and ${\rm sgn}\mu=+1$. The SUSY signal (solid) and the SM background (shaded) are shown.