Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userLight neutralinos at LHC in cosmologically-inspired scenarios: new benchmarks in the search for supersymmetry
103
0
0.0
(
0
)
Authors
A. Bottino
Ask ChatGPT about the research
No Arabic abstract
We study how the properties of the four neutralino states, chi_i (i = 1, 2, 3, 4), can be investigated at the Large Hadron Collider (LHC), in the case when the lightest one, chi_1, has a mass m_chi < 50 GeV and is stable. This situation arises naturally in supersymmetric models where gaugino masses are not unified at a Grand Unified (GUT) scale and R-parity is conserved. The main features of these neutralino states are established by analytical and numerical analyses, and two scenarios are singled out on the basis of the cosmological properties required for the relic neutralinos. Signals expected at LHC are discussed through the main chain processes started by a squark, produced in the initial proton-proton scattering. We motivate the selection of some convenient benchmarks, in the light of the spectroscopical properties (mass spectrum and transitions) of the four neutralino states. Branching ratios and the expected total number of events are derived in the various benchmarks, and their relevance for experimental determination of neutralino properties is finally discussed.
rate research
Read More
New strong interactions at the LHC may exhibit a richer structure than expected from simply rescaling QCD to the electroweak scale. In fact, a departure from rescaled QCD is required for compatibility with electroweak constraints. To navigate the space of possible scenarios, we use a simple framework, based on a 5D model with modifications of AdS geometry in the infrared. In the parameter space, we select two points with particularly interesting phenomenology. For these benchmark points, we explore the discovery of triplets of vector and axial resonances at the LHC.
We study the muon $(g-2)_{mu}$ anomaly in light of neutralino dark matter and the LHC. We scan the MSSM parameters relevant to $(g-2)_{mu}$ and focus on three distinct cases with different neutralino compositions. We find that the 2$sigma$ range of $(g-2)_{mu}$ requires the smuon ($tilde{mu}_1$) to be lighter than $sim$ 500 (1000) GeV for $tan beta=10,(50)$. Correspondingly the two lightest neutralinos, $tilde{chi}_{1}^0, tilde{chi}_{2}^0$, have to be lighter than $sim$ 300 (650) GeV and 900 (1000) GeV respectively. We explore the prospects of searching the light smuon and neutralinos at the LHC, in conjunction with constraints arising from indirect dark matter (DM) detection experiments. The upcoming run of the LHC will be able to set $95%$ CL exclusion limit on $M_{tilde{chi}_{2}^0}$ ($sim 475 - 1300$ GeV) and $m_{tilde{l}}$ ($sim 670-775$ GeV) with $M_{tilde{chi}_{1}^0} sim 100-250$ GeV at 3000 fb$^{-1}$ luminosity in multi-lepton + missing energy channel.
In view of the latest LEP data we consider the effects of charginos and neutralinos on the two-photon and bbbar signatures of the Higgs at the LHC. Assuming the usual GUT inspired relation between M_1 and M_2 we show that there are only small regions with moderate tanbeta and large stop mixings that may be dangerous. Pathological models not excluded by LEP which have degeneracy between the sneutrino and the chargino are however a real danger because of large branching fraction of the Higgs into invisibles. We have also studied models where the gaugino masses are not unified at the GUT scale. We take M_1=M_2/10 as an example where large reductions in the signal at the LHC can occur. However we argue that such models with a very light neutralino LSP may give a too large relic density unless the sleptons are light. We then combine this cosmological constraint with neutralino production with light sfermions to further reduce the parameter space that precludes observability of the Higgs at the LHC. We still find regions of parameter space where the drops in the usual Higgs signals at the LHC can be drastic. Nonetheless, in such scenarios where Higgs may escape detection we show that one should be able to produce all charginos and neutralinos. Although the heavier of these could cascade into the Higgs, the rates are not too high and the Higgs may not always be recovered this way.
In this report we review recent theoretical progress and the latest experimental results in jet substructure from the Tevatron and the LHC. We review the status of and outlook for calculation and simulation tools for studying jet substructure. Following up on the report of the Boost 2010 workshop, we present a new set of benchmark comparisons of substructure techniques, focusing on the set of variables and grooming methods that are collectively known as top taggers. To facilitate further exploration, we have attempted to collect, harmonise, and publish software implementations of these techniques.
The neutralino sector in E_6 inspired supersymmetric models with extra neutral gauge bosons and singlet Higgs fields contains additional gaugino and singlino states compared to the MSSM. We discuss the neutralino mixing in rank 5 and rank 6 models and analyze the supersymmetric parameter space where the light neutralinos have mainly singlino or MSSM character. The neutralino character, resonance effects of the new gauge bosons and, assuming mSUGRA-type RGEs, different selectron masses lead to significant differences between the MSSM and the extended models in neutralino production at an e^+e^- linear collider. Beam polarization may improve the signatures to distinguish between the models. In an appendix, we present the mass terms of the gauge bosons, charginos and sfermions which show a significant different mass spectrum than in the MSSM and give all relevant neutralino couplings.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
