Monojet signatures from heavy colored particles: future collider sensitivities and theoretical uncertainties

Journal Article · Sat Aug 25 00:00:00 EDT 2018 · European Physical Journal. C, Particles and Fields

DOI:https://doi.org/10.1140/epjc/s10052-018-6149-6· OSTI ID:1475542

Chakraborty, Amit ^[1]; Kuttimalai, Silvan ^[2]; Lim, Sung Hak  ^[1]; Nojiri, Mihoko M. ^[3]; Ruiz, Richard  ^[4]

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1. National Lab. for High Energy Physics (KEK), Tsukuba (Japan). Theory Center
2. SLAC National Accelerator Lab., Menlo Park, CA (United States)
3. National Lab. for High Energy Physics (KEK), Tsukuba (Japan). Theory Center; Graduate Univ. of Advanced Studies (Sokendai) Tsukuba (Japan)
4. Durham Univ. (United Kingdom). Dept. of Physics, Inst. for Particle Physics Phenomenology (IPPP)

In models with colored particle Q that can decay into a dark matter candidate X, the relevant collider process pp→$$Q\bar{Q}$$→$$X\bar{X}$$+ jets gives rise to events with significant transverse momentum imbalance. When the masses of Q and X are very close, the relevant signature becomes monojet-like, and Large Hadron Collider (LHC) search limits become much less constraining. In this paper, we study the current and anticipated experimental sensitivity to such particles at the High-Luminosity LHC at s√=14 TeV with L=3 ab^-1 of data and the proposed High-Energy LHC at s√=27 TeV with L=15 ab^-1 of data. We estimate the reach for various Lorentz and QCD color representations of Q. Identifying the nature of Q is very important to understanding the physics behind the monojet signature. Therefore, we also study the dependence of the observables built from the pp→$$Q\bar{Q}$$ + j process on Q itself. Here, using the state-of-the-art Monte Carlo suites MadGraph5_aMC@NLO+Pythia8 and Sherpa, we find that when these observables are calculated at NLO in QCD with parton shower matching and multijet merging, the residual theoretical uncertainties are comparable to differences observed when varying the quantum numbers of Q itself. We find, however, that the precision achievable with NNLO calculations, where available, can resolve this dilemma.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC02-76SF00515
• OSTI ID: 1475542
• Journal Information: European Physical Journal. C, Particles and Fields, Vol. 78, Issue 8; ISSN 1434-6044
• Publisher: Springer
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS