scholarly journals NEW LIMITS ON TOP SQUARK NLSP FROM ATLAS 4.7 fb-1 DATA

2012 ◽  
Vol 27 (32) ◽  
pp. 1250188 ◽  
Author(s):  
ARGHYA CHOUDHURY ◽  
AMITAVA DATTA
Keyword(s):  
Dark Matter ◽  
Lower Limit ◽  
New Physics ◽  
Supersymmetric Particle ◽  
Top Squark ◽  
Decay Modes ◽  
Dark Matter Relic Density ◽  
Relic Density ◽  
200 Gev ◽  
New Physics Search

Using the ATLAS 4.7 fb-1 data on new physics search in the jets + [Formula: see text] channel, we obtain new limits on the lighter top squark [Formula: see text] considering all its decay modes assuming that it is the next to lightest supersymmetric particle (NLSP). If the decay [Formula: see text] dominates and the production of dark matter relic density is due to NLSP–lightest supersymmetric particle (LSP) co-annihilation then the lower limit on [Formula: see text] is 240 GeV. The limit changes to 200 GeV if the decay [Formula: see text] dominates. Combining these results it follows that [Formula: see text] NLSP induced baryogenesis is now constrained more tightly.

scholarly journals Displaced new physics at colliders and the early universe before its first second

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Lorenzo Calibbi ◽  
Francesco D’Eramo ◽  
Sam Junius ◽  
Laura Lopez-Honorez ◽  
Alberto Mariotti
Keyword(s):  
Dark Matter ◽  
Early Universe ◽  
Upper Bound ◽  
New Physics ◽  
Early History ◽  
Relic Density ◽  
History Of ◽  
Indirect Information ◽  
The Universe

Abstract Displaced vertices at colliders, arising from the production and decay of long-lived particles, probe dark matter candidates produced via freeze-in. If one assumes a standard cosmological history, these decays happen inside the detector only if the dark matter is very light because of the relic density constraint. Here, we argue how displaced events could very well point to freeze-in within a non-standard early universe history. Focusing on the cosmology of inflationary reheating, we explore the interplay between the reheating temperature and collider signatures for minimal freeze-in scenarios. Observing displaced events at the LHC would allow to set an upper bound on the reheating temperature and, in general, to gather indirect information on the early history of the universe.

scholarly journals Precise Prediction of the Dark Matter Relic Density within the MSSM

2016 ◽  
Author(s):  
Julia Harz ◽  
Bjorn Herrmann ◽  
Michael Klasen ◽  
Karol Kovarik ◽  
P. Steppeler
Keyword(s):  
Dark Matter ◽  
Dark Matter Relic Density ◽  
Relic Density ◽  
Precise Prediction

scholarly journals Dark matter freeze-out during matter domination

2018 ◽  
Vol 33 (29) ◽  
pp. 1850181 ◽  
Author(s):  
Saleh Hamdan ◽  
James Unwin
Keyword(s):  
Dark Matter ◽  
Energy Density ◽  
Big Bang ◽  
Big Bang Nucleosynthesis ◽  
Hubble Rate ◽  
Dark Matter Relic Density ◽  
Relic Density ◽  
The Masses ◽  
The Universe ◽  
Freeze Out

We highlight the general scenario of dark matter freeze-out while the energy density of the universe is dominated by a decoupled non-relativistic species. Decoupling during matter domination changes the freeze-out dynamics, since the Hubble rate is parametrically different for matter and radiation domination. Furthermore, for successful Big Bang Nucleosynthesis the state dominating the early universe energy density must decay, this dilutes (or repopulates) the dark matter. As a result, the masses and couplings required to reproduce the observed dark matter relic density can differ significantly from radiation-dominated freeze-out.

THREE GENERATIONS: A PREDICTION FULFILLED

1990 ◽  
Vol 05 (09) ◽  
pp. 645-651
Author(s):  
JORGE L. LOPEZ ◽  
D.V. NANOPOULOS
Keyword(s):  
Dark Matter ◽  
Strong Correlation ◽  
Planck Scale ◽  
New Physics ◽  
Supersymmetric Particle ◽  
Three Generations ◽  
Unified Theories ◽  
The Universe

We recall the theoretical arguments that led us more than ten years ago to predict that there are only three generations. Quark-lepton mass relations (mb/mτ ≈ 2.8), as universally come out from unified theories at superhigh energies (close to the Planck scale), are the key point. We further argue that fractional deviations from Nν=3 may signal new physics. The supersymmetric decay Z→ÑÑ, with Ñ the lightest neutralino and lightest supersymmetric particle (LSP), easily fits the bill. In the specific case of flipped (SU(5)×U(1)) unification, there is a strong correlation between mt≈ O(90 ± 10) GeV, slepton masses of O(50 GeV) and the closure of the Universe due to Ñ dark matter, while ΔNν ≈ (0.1–0.5).

scholarly journals Searching for supersymmetry and its avatars

2019 ◽  
Vol 377 (2161) ◽  
pp. 20190069 ◽  
Author(s):  
John Ellis
Keyword(s):  
Dark Matter ◽  
Higgs Mass ◽  
Cold Dark Matter ◽  
Hadron Collider ◽  
Charged Particles ◽  
New Physics ◽  
Supersymmetric Particle ◽  
Laser Arrays ◽  
Super Symmetry ◽  
The Aesthetic

Why continue looking for supersymmetry? Over and above the aesthetic and theoretical motivations from string theory, there are several longstanding pheno- menological motivations for TeV-scale super- symmetry, such as the electroweak scale, and the lightest supersymmetric particle as cold dark matter. Run 1 of the Large Hadron Collider (LHC) has actually provided three extra motivations, namely the stabilization of the electroweak vacuum, and successful predictions for the Higgs mass and couplings. How to look for it? There are several examples of emergent supersymmetry, the most recent being on the surfaces of topological insulators, and some sort of effective supersymmetry could be useful for boosting the power of laser arrays. At the LHC, attention is moving towards signatures that had previously been neglected, such as long-lived charged particles—which might be an opportunity for the MoEDAL experiment. This article is part of a discussion meeting issue ‘Topological avatars of new physics’.

scholarly journals Search for $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$ charged dark matter with neutrino telescope

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Kento Asai ◽  
Shohei Okawa ◽  
Koji Tsumura
Keyword(s):  
Dark Matter ◽  
Resonance Effect ◽  
Neutrino Telescope ◽  
Dirac Fermion ◽  
Dark Matter Relic Density ◽  
Relic Density ◽  
Matter Model ◽  
Model Independent ◽  
Model Characteristic ◽  
Dark Matter Model

Abstract We study a simple Dirac fermion dark matter model in $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$ U 1 L μ − L τ theory. The new light gauge boson X plays important roles in both dark matter physics and the explanation for the muon g− 2 anomaly. The observed dark matter relic density is realized by a large $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$ U 1 L μ − L τ charge without introducing a resonance effect of the X boson. As a by-product of the model, characteristic neutrino signatures from sub-GeV dark matter ψ are predicted depending on the mass spectrum. We formulate the analysis of $$ \psi \overline{\psi}\to \nu \overline{\nu} $$ ψ ψ ¯ → ν ν ¯ , and of $$ \psi \overline{\psi}\to XX $$ ψ ψ ¯ → XX followed by $$ X\to \nu \overline{\nu} $$ X → ν ν ¯ in a model independent way. The energy spectrum of neutrinos in the former process is monochromatic while in the latter process is bowl-shape. We also evaluate sensitivity at Super-Kamiokande and future Hyper-Kamiokande detectors. The analysis is finally applied to the $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$ U 1 L μ − L τ dark matter model.

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