arXiv subjects

Eita Nakamura

Publications and source records attributed to Eita Nakamura.

24 records · Page 2Linked to original sources

arXiv2011

Discovery Potential for Low-Scale Gauge Mediation at Early LHC

Low-scale gauge-mediated supersymmetry(SUSY)-breaking (GMSB) models with gravitino mass m_{3/2}<16 eV are attractive, since there are no flavor and cosmological problems. In this paper, we thoroughly study the collider signal in the case that the next-to-lightest SUSY particle is the bino or slepton and investigate the discovery potential of the LHC. Our result is applicable to a wider class of GMSB models other than the minimal GMSB models and we pay particular attention to realistic experimental setups. We also apply our analysis to the minimal GMSB models with a metastable SUSY-breaking vacuum and we show, by requiring sufficient stability of the SUSY-breaking vacuum, these models can be tested at an early stage of the LHC.

hep-ph↗

arXiv2009

Low-Scale Gauge Mediation and Composite Messenger Dark Matter

In recent works, we have proposed a possible dark matter in composite messenger gauge mediation models. In this paper, we discuss the details of a composite messenger model taking a possible supersymmetry breaking scenario and show that the correct dark matter abundance and a successful gauge mediation can be realized.

hep-ph↗

arXiv2009

Inverse Problem of Cosmic-Ray Electron/Positron from Dark Matter

We discuss the possibility of solving the inverse problem of the cosmic-ray electron/positron from decaying/annihilating dark matter, and show simple analytic formulae to reconstruct the source spectrum of the electron/positron from the observed flux. We also illustrate our approach by applying the obtained formula to the just released Fermi data as well as the new HESS data.

hep-ph↗

arXiv2008

Decaying Dark Matter Baryons in a Composite Messenger Model

A baryonic bound state with a mass of O(100) TeV, which is composed of strongly interacting messenger quarks in the low scale gauge mediation, can naturally be the cold dark matter. Interestingly, we find that such a baryonic dark matter is generically metastable, and the decay of this dark matter can naturally explain the anomalous positron flux recently observed by the PAMELA collaboration.

hep-ph↗

arXiv2008

Strongly Interacting Gauge Mediation at the LHC

Strongly interacting gauge mediation (SIGM) of supersymmetry breaking is very attractive, since it naturally predicts a light gravitino of mass $\lsim{\cal O}(10)$ eV, which causes no cosmological problem. We discuss various signatures of the SIGM in the early stage (a low integrated luminosity period) of the LHC experiments. We show, in particular, a possible way to discriminate it from the conventional gauge mediation by counting the number of high $P_{\rm T}$ leptons.

hep-ph↗

arXiv2008

A Measurement of Neutralino Mass at the LHC in Light Gravitino Scenarios

We consider supersymmetric (SUSY) models in which a very light gravitino is the lightest SUSY particle. Assuming that a neutralino is the next-to-lightest SUSY particle, we present a measurement of the neutralino mass at the LHC in two photons + missing energy events, which is based on the MT2 method. It is a direct measurement of the neutralino mass itself, independent of other SUSY particle masses and patterns of cascade decays before the neutralino is produced.

hep-ph↗