K. Mimasu — Page 2 | Searcharxiv

arXiv2013

Uncovering quasi-degenerate Kaluza-Klein Electro-Weak gauge bosons with top asymmetries at the LHC

By exploiting the correlation between charge and spin polarisation asymmetries in t-tbar, we show that combining the two observables could identify the presence of quasi-degenerate states in a resonant signal at the LHC. As an example, we investigate experimental signatures emerging in top-antitop final states in the context of a model where the Standard Model Electro-Weak sector is allowed to propagate in large extra--dimensions of TeV^-1 size while the colour sector is localised. Assuming current experimantal constraints from the 7 and 8 TeV runs and taking into account the estimated top (anti-top) reconstruction efficiencies, we find that the 14 TeV upgraded LHC with the planned integrated luminosity L=100 fb^-1 could access these quasi-degenerate multiple resonances and explore for the first time the rich phenomenology in the asymmetry observables. The main outcome would be having measurable quantities, complementary to the usual total and differential cross sections, capable of distiguishing a quasi-degenerate multiply resonant spectrum from a `standard' single resonance that could present a similar signal in a bump hunt analysis.

hep-ph↗

arXiv2012

Z' signals in polarised top-antitop final states at the LHC

We study the sensitivity of top pair production at the Large Hadron Collider (LHC) to the nature of an underlying Z' boson, including full tree level standard model background effects and interferences while assuming realistic final state reconstruction efficiencies. We demonstrate that exploiting asymmetry observables represents a promising way to distinguish between a selection of benchmark Z' models due to their unique dependences on the chiral couplings of the new gauge boson

hep-ph↗

arXiv2012

The role of charge and spin asymmetries in profiling Z'-> tt events

We study the sensitivity of top pair production at the Large Hadron Collider (LHC) to the nature of an underlying Z' boson, including full tree level standard model background effects and interferences while assuming realistic final state reconstruction efficiencies. We demonstrate that exploiting asymmetry observables represents a promising way to distinguish between a selection of benchmark Z' models due to their unique dependences on the chiral couplings of the new gauge boson.

hep-ph↗

arXiv2012

Non-exotic $Z'$ signals in $\ell^+\ell^-$, $b\bar b$ and $t\bar t$ final states at the LHC

In the attempt to fully profile a $Z'$ boson accessible at the Large Hadron Collider (LHC), we study the sensitivity of di-lepton (for the electron, muon and tauon cases) and di-quark (for the case of the heavy flavours, $t$ and, possibly, $b$) samples to the nature of the new gauge state, for a one-dimensional class of non-exotic $Z'$ bosons. Assuming realistic final state reconstruction efficiencies and error estimates, we find that, depending on the CERN collider energy and luminosity, the best chances of extracting the $Z'$ quantum numbers occur when two or more of these channels are simultaneously explored, as none of them separately enables one to fully probe the parameter spaces of the aforementioned models. Effects of Standard Model (SM) background as well interferences between this and the various $Z'$ signals have been accounted for. A complete study of cross sections and asymmetries (both spatial and spin ones) makes clear the need for complementarity, especially for their disentanglement over the full parameter space.

hep-ph↗

arXiv2012

Distinguishing Z' models with polarised top pairs

We study the sensitivity of top pair production at the Large Hadron Collider (LHC) to the nature of an underlying Z' boson, including full tree level standard model background effects and interferences. We demonstrate that exploiting combinations of asymmetry observables will enable one to distinguish between a selection of `benchmark' Z' models while assuming realistic final state reconstruction efficiencies and error estimates.

hep-ph↗

arXiv2012

Z' signals in polarised top-antitop final states

We study the sensitivity of top-antitop samples produced at all energy stages of the Large Hadron Collider (LHC) to the nature of an underlying Z' boson, in presence of full tree level standard model (SM) background effects and relative interferences. We concentrate on differential mass spectra as well as both spatial and spin asymmetries thereby demonstrating that exploiting combinations of these observables will enable one to distinguish between sequential Z's and those pertaining to Left-Right symmetric models as well as E6 inspired ones, assuming realistic final state reconstruction efficiencies and error estimates.

hep-ph↗

arXiv2012

Top quark phenomenology of the ADD model and the Minimal Length Scenario

We study top-(anti)quark pair production at the Tevatron and Large Hadron Collider (LHC) in the context of the Minimal Length Scenario (MLS) of the Arkani-Hamed, Dimopoulos and Dvali (ADD) model of extra dimensions (XDs). We show that sizable effects onto both the integrated and differential cross section due to graviton mediation are expected for a String scale, M_S, of O(1-10TeV) and several XDs, δ, all compatible with current experimental constraints. Potential limits on M_S are extracted. We also highlight clear phenomenological differences between a simple ADD scenario and its modification based on using the MLS as a natural regulator for divergent amplitudes of virtual KK graviton exchange.

hep-ph↗

arXiv2012

ADD and MLS signals in top-antitop final states

We study top-(anti)quark pair production at the Tevatron and Large Hadron Collider (LHC) in the context of the Minimal Length Scenario (MLS) of the Arkani-Hamed, Dimopoulos and Dvali (ADD) model of extra dimensions (XDs). We show that sizable effects onto both the integrated and differential cross section due to graviton mediation are expected for a String scale, M_S, of O(1-10TeV) and several XDs, δ, all compatible with current experimental constraints. Potential limits on M_S are extracted. We also highlight clear phenomenological differences between a simple ADD scenario and its modification based on using the MLS as a natural regulator for divergent amplitudes of virtual KK graviton exchange.

hep-ph↗