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Seminar | HEP Lunch Seminar | High Energy Physics Division

Searches for Hadronic Resonances at CMS

HEP Lunch Seminar

Abstract: Searches for dijet resonances have a long history at hadron colliders, going back to the UA1 and UA2 experiments at the SppS. At each new collision energy, such searches have the exciting potential to discover new hadronic resonances. Due to large QCD backgrounds and limited trigger bandwidths, however, the lower mass bounds of such searches have moved higher and higher, with recent results from the ATLAS and CMS experiments probing resonances well only above 1 TeV. To maintain sensitivity to resonances with lower masses, new analysis techniques are required. Examples of such techniques developed in recent years include using of trigger-level objects to reduce the recorded event size, employing bottom quark tagging at the trigger level, and searching for resonances produced with significant initial state radiation (ISR).

I will present recent results from the CMS experiment for dijet resonances using Run 2 data, covering three orders of magnitude in mass from O(10 GeV) to O(10 TeV). For masses above 1.8 TeV, the high-mass dijet search features a new background estimation technique using a control samples of jet pairs with large pseudorapidity separation. A similar search requiring a third jet from ISR, performed using trigger-level-objects, probes masses from 350 to 700 GeV. Finally, masses from 10 to 450 GeV are probed by requiring the resonance to be produced with large transverse momentum due to ISR. In this range, which includes the W, Z, and Higgs bosons, the resonance is reconstructed as a single large-radius jet with two-pronged substructure.