Projected Performance of an Upgraded CMS Detector at the LHC and HL-LHC: Contribution to the Snowmass Process

TL;DR

The paper evaluates CMS detector upgrades for the LHC and HL-LHC, projecting physics reach across Higgs physics, SUSY, exotic particles, top and electroweak sectors, and heavy-ion physics. It uses extrapolations from current 7/8 TeV results under Phase 1 and Phase 2 upgrade scenarios and two uncertainty frameworks to estimate future precision and discovery potential up to 3000 fb^-1 at 14 TeV. Key findings include substantial improvements in Higgs coupling measurements and CP properties, extended mass reach for gluinos and vector-like quarks, and a robust heavy-ion program enabling detailed studies of parton energy loss in the quark-gluon plasma. The work demonstrates that the CMS upgrade strategy will preserve and enhance sensitivity to Standard Model tests and beyond-Standard-Model phenomena in the HL-LHC era, providing broad scientific payoff across collider and nuclear physics domains.

Abstract

The physics reach of the CMS detector achievable with 300(0) inverse femtobarns of proton-proton collisions recorded at sqrt(s)=14 TeV is presented. Ultimate precision on measurements of Higgs boson properties, top quark physics, and electroweak processes are discussed, as well as the discovery potential for new particles beyond the standard model. In addition, the potential for future heavy ion physics is presented. This document has been submitted as a white paper to the Snowmass process, an exercise initiated by the American Physical Society's Division of Particles and Fields to assess the long-term physics aspirations of the US high energy physics community.

Figures (31)

• Figure 1: Left: LHC integrated luminosity delivered to CMS during the 2010 (green), 2011 (red), and 2012 (blue) running periods. Right: ratio of parton luminosities at the LHC for center-of-mass energies of $8$ and $14\,\text{Te\spaceV}\xspace$ relative to $7\,\text{Te\spaceV}\xspace$. Luminosities are shown separately for processes initiated by $gg$, $qg$, and $qq$ collisions Sterling.
• Figure 2: Left: Conceptual layout comparing the different layers and disks in the current and upgrade pixel detectors. Right: Transverse-oblique view comparing the pixel barrel layers in the two detectors.
• Figure 3: Average tracking efficiencies (a) and fake rates (b) as a function of pile-up for the $t\bar{t}$ event selection.
• Figure 4: Transverse IP resolution for muon tracks as a function of momentum for different pseudorapidity regions. The current and new detectors arerepresented with black dots and red triangles, respectively.
• Figure 5: Transverse (top) and longitudinal (bottom) primary vertex position resolutions as a function of the number of tracks; without pile-up (left) and at a 50 pile-up (right). The current and new detectors are respectively represented with black dots and red squares.