Search for microscopic black holes in a like-sign dimuon final state using large track multiplicity with the ATLAS detector

Abstract

A search is presented for microscopic black holes in a like-sign dimuon final state in proton-proton collisions at ffiffi ffi s p ¼ 8 TeV. The data were collected with the ATLAS detector at the Large Hadron Collider in 2012 and correspond to an integrated luminosity of 20:3 fb À1 . Using a high track multiplicity requirement, 0:6 AE 0:2 background events from Standard Model processes are predicted and none observed. This result is interpreted in the context of low-scale gravity models and 95% C.L. lower limits on microscopic black hole masses are set for different model assumptions.

Composite charge 8/3 resonances at the LHC

“…The X 8 / 3 then decays with ∼ 100% probability into W + W + t, with the top quark subsequently decaying into W + b, as illustrated in the left panel of figure 1. Most of the times the W 's decay hadronically, leading to signatures with large numbers of jets; searches for these topologies already exist in the context of microscopic black holes [79,80]. As we will show in the section 3, current sensitivity of this type of searches does not allow to put significant constraints on models with the interaction eq.…”

“…Searches for microscopic black holes [79,80], looking for events with a large number of hard jets and leptons in the final states, are sensitive to the pair produced X 8 / 3 , giving rise to 6 W bosons and 2 b-quarks, which subsequently can decay into 14 hard objects.…”

Collider searches for nonperturbative low-scale gravity states

“…Thermal gravity states such as GR black holes and string balls have been searched for by ATLAS [20] and CMS [21,22,23] in multi-jet events. In addition, ATLAS has search for the same states in +jets events [24,25], and same-sign dimuon events with a large number of tracks [26,27].…”

“…Model-dependent limits have been set in multi-jet searches by ATLAS [20] and CMS [21,22,23], and in +jets [24,25] and dimuon [26,27] searches in ATLAS. The models used are given by rather standard configurations of the CHARYBDIS2 and BlackMax generators.…”

Status and Implications of BSM Searches at the LHC

“…In addition, model-independent limits are provided as a function of the scalar sum of the p T s of all the final-state objects, and the particle multiplicity, which allows straight-forward possible re-interpretation of the results. ATLAS has performed three searches for extra dimensions: two searches target quantum BH in either the lepton+jets final state [97] or the photon+jet final state [98]; and the third search targets an ADD model with like-sign dimuons [99]. Again, the lower mass limits are reported for several different scenarios and model assumptions and are in the 5 TeV range, as summarized in Table 2.…”