Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userPrompt Signals and Displaced Vertices in Sparticle Searches for Next-to-Minimal Gauge Mediated Supersymmetric Models
83
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We study the LHC phenomenology of the next-to-minimal model of gauge-mediated supersymmetry breaking (NMGMSB), both for Run I and Run II. The Higgs phenomenology of the model is consistent with observations: a 125 GeV Standard Model-like Higgs which mixes with singlet-like state of mass around 90 GeV that provides a 2$sigma$ excess at LEP II. The model possesses regions of parameter space where a longer-lived lightest neutralino decays in the detector into a gravitino and a $b-$jet pair or a tau pair. We investigate current lower bounds on sparticle masses and the discovery potential of the model, both via conventional sparticle searches and via searches for displaced vertices. The strongest bound from searches for promptly decaying sparticles yields a lower limit on the gluino mass of 1080 GeV. An analysis of 100 fb$^{-1}$ from Run II, on the other hand, is expected to be sensitive up to 1900 GeV. The displaced vertex searches from Run I suffer from a very low signal efficiency, mainly due to the presence of $b-$quarks in the final state. We show how the displaced vertex cuts might be relaxed in order to improve signal efficiency, while simultaneous prompt objects can be used to cut down background. We find that a combined search strategy with both prompt and displaced cuts potentially has a far better sensitivity to this model than either set alone, motivating a fully fledged experimental study.
rate research
Read More
We describe a major extension of the SOFTSUSY spectrum calculator to include the calculation of the decays, branching ratios and lifetimes of sparticles into lighter sparticles, covering the next-to-minimal supersymmetric standard model (NMSSM) as well as the minimal supersymmetric standard model (MSSM). This document acts as a manual for the new version of SOFTSUSY, which includes the calculation of sparticle decays. We present a comprehensive collection of explicit expressions used by the program for the various partial widths of the different decay modes in the appendix.
The QCD axion is a well-motivated addition to the standard model to solve the strong $CP$ problem. If the axion acquires mass dominantly from a hidden sector, it can be as heavy as $O(1)$ GeV, and the decay constant can be as low as $O(100)$ GeV without running into the axion quality problem. We propose new search strategies for such heavy QCD axions at the Belle II experiment, where the axions are expected to be produced via $Bto K a$. We find that a subsequent decay $ato 3pi$ with a displaced vertex leads to a unique signal with essentially no background, and that a dedicated search can explore the range $O(1-$$10)$ TeV of decay-constant values. We also show that $ato gammagamma$ can cover a significant portion of currently unexplored region of $150 lesssim m_a lesssim 500$ MeV.
We describe an extension of the SOFTSUSY spectrum calculator to include two-loop supersymmetric QCD (SUSYQCD) corrections of order $mathcal{O}(alpha_s^2)$ to gluino and squark pole masses, either in the minimal supersymmetric standard model (MSSM) or the next-to-minimal supersymmetric standard model (NMSSM). This document provides an overview of the program and acts as a manual for the new version of SOFTSUSY, which includes the increase in accuracy in squark and gluino pole mass predictions.
We consider the fully constrained version of the next-to-minimal supersymmetric extension of the standard model (cNMSSM) in which a singlet Higgs superfield is added to the two doublets that are present in the minimal extension (MSSM). Assuming universal boundary conditions at a high scale for the soft supersymmetry-breaking gaugino, sfermion and Higgs mass parameters as well as for the trilinear interactions, we find that the model is more constrained than the celebrated minimal supergravity model. The phenomenologically viable region in the parameter space of the cNMSSM corresponds to a small value for the universal scalar mass m_0: in this case, one single input parameter is sufficient to describe the phenomenology of the model once the available constraints from collider data and cosmology are imposed. We present the particle spectrum of this very predictive model and discuss how it can be distinguished from the MSSM.
We investigate multilepton LHC signals arising from electroweak processes involving sleptons. We consider the framework of general gauge mediated supersymmetry breaking, focusing on models where the low mass region of the superpartner spectrum consists of the three generations of charged sleptons and the nearly massless gravitino. We demonstrate how such models can provide an explanation for the anomalous four lepton events recently observed by the CMS collaboration, while satisfying other existing experimental constraints. The best fit to the CMS data is obtained for a selectron/smuon mass of around 145 GeV and a stau mass of around 90 GeV. These models also give rise to final states with more than four leptons, offering alternative channels in which they can be probed and we estimate the corresponding production rates at the LHC.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
