New limits on coloured three jet resonances
- PDF / 546,491 Bytes
- 23 Pages / 595.276 x 841.89 pts (A4) Page_size
- 47 Downloads / 167 Views
Springer
Received: March 13, 2020 Accepted: August 18, 2020 Published: September 21, 2020
Hassan Easa, Thomas Gregoire and Daniel Stolarski Ottawa-Carleton, Institute for Physics, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
E-mail: [email protected], [email protected], [email protected] Abstract: We consider experimental limits on colour triplet fermions that decay dominantly to three jets via a scalar mediator that can be on- or off-shell. These fermions arise in top-partner models that can solve the hierarchy problem, and limits on this scenario are weaker than those on traditional top-partner models because of the messy all-hadronic final state with significant backgrounds. We do find, however, that while there are no dedicated searches for this scenario, especially in case of an on-shell mediator, the suite of LHC allhadronic searches still constrains a significant portion of the parameter space. In particular, we find that searches for pair production of di-jet and tri-jet resonances are complementary, covering different regions of parameter space. We also find that if the final state is rich in bjets, current limits do not change significantly relative to the scenario with all light jets, and we describe how modifications of current search strategies can improve limits in that case. Keywords: Jets, Phenomenological Models ArXiv ePrint: 2003.00014
c The Authors. Open Access, Article funded by SCOAP3 .
https://doi.org/10.1007/JHEP09(2020)131
JHEP09(2020)131
New limits on coloured three jet resonances
Contents 1 Introduction
1
2 Bounds from LHC searches 2.1 CMS pair-produced three-jet resonances 2.2 ATLAS pair-produced di-jet resonances
3 4 8 11
4 Conclusion
12
A CMS three jet resonance search
13
B ATLAS di-jet resonance search
15
C CMS three jet resonance search at
√
s = 8 TeV
D Multijet background
1
16 17
Introduction
With the discovery of the Higgs boson [1, 2] at the large hadron collider (LHC), the Standard Model of particle physics (SM) is complete. The confirmation of the properties of the Higgs being SM-like and the lack of discovery of new physics at the TeV scale exacerbates the hierarchy problem: what cuts off the quantum corrections to the Higgs mass? One well known solution to the hierarchy problem poses the existence of fermionic top partners, fermions with the same quantum numbers as the top quark whose contributions to the Higgs mass parameter cancel those of the top quark. These can appear in composite Higgs models [3–7] and Little Higgs models [8, 9]. In these models, top partners typically decay to a top quark and a Higgs or Z, or to a bottom quark and W . LHC searches for top partners in these modes are extensive, both in pair production [10–19] and in single production [20–30], with limits ≈1.3–1.66 TeV on the mass of the top partners from the various searches depending on their branching ratios. Due to the lack of discovery, it is critical to explore alternative models, particularly those with different dec
Data Loading...
