Related papers: On long-lived electroweak-singlet coloured scalars
New physics at the TeV scale is highly anticipated at the LHC. New particles with color, if within the LHC energy reach, will be copiously produced. One such particle is a diquark, having the quantum numbers of two quarks, and can be a…
Color-octet resonances arise in many well motivated theories beyond the standard model. As colored objects they are produced copiously at the LHC and can be discovered in early searches for new physics in dijet final states. Once they are…
A search is presented for long-lived particles with a mass between 25 and 50 GeV$/c^2$ and a lifetime between 1 and 200 ps in a sample of proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=7$ TeV, corresponding to an…
We study the phenomenology of a hypercharge-zero SU(2) triplet scalar whose existence is motivated by two-step electroweak symmetry-breaking. We consider both the possibility that the triplets are stable and contribute to the dark matter…
We study signals at the Large Hadron Collider (LHC) for the Kaluza-Klein (KK) excitations of electroweak charged gauge bosons in the framework of the Standard Model (SM) fields propagating in the bulk of a warped extra dimension. Such a…
We study a model in which the electroweak symmetry is dynamically broken by technicolor interactions and the symmetry-breaking is communicated to the quarks and leptons by a weak doublet of scalar fields. The scalars may be regarded as…
A search for long-lived particles, which have come to rest within the ATLAS detector, is presented. The subsequent decays of these long-lived particles can produce high-momentum jets, resulting in large out-of-time energy deposits in the…
We propose a simple extension of the Standard Model (SM) by adding an extra U(1) symmetry which is hidden from the SM sector. Such a hidden U(1) has not been considered before, and its existence at the TeV scale can be explored at the LHC.…
Searching for long-lived particles (LLPs) beyond the Standard Model (SM) is a promising direction in collider experiments. The Georgi-Machacek (GM) model extends the scalar sector in the SM by introducing various new scalar bosons. In this…
While an additional scalar multiplet over and above the Standard Model can lead to a strong electroweak phase transition, depending on its quantum numbers, it also potentially confronts crucial constraints from theory and experiments.…
It is usually assumed that the proton stability requires the coloured triplet partner of the electroweak Higgs doublet to be superheavy (with a mass $\sim M_{GUT}$). We show that this is a very model-dependent statement and the colour…
Current limits from the LHC on fourth generation quarks are already at the unitarity bound of 500 GeV or so. If they exist, the strong Yukawa couplings are turning nonperturbative, and may form bound states. We study the domain of m_{b'}…
Charged scalar particles introduced in some extensions of the standard model can induce $\tau$ leptonic decay at tree level. We find that with some charged SU(2)-singlet scalar particles, like ones introduced in Zee-type models, $\tau$…
We analyze one-loop vacuum stability, perturbativity, and phenomenological constraints on a complex singlet extension of the Standard Model (SM) scalar sector containing a scalar dark matter candidate. We study vacuum stability…
Di-jet resonance searches are simple, yet powerful and model-independent, probes for discovering new particles at hadron colliders. Once such a resonance has been discovered it is important to determine the mass, spin, couplings, chiral…
We show that the late-decaying particle scenario may be realized in the supersymmetric singlet majoron model with the majoron scale $10-200$ TeV. The smajoron decaying into two neutrinos is the late-decaying particle with the mass $0.1-1$…
Long-lived particles are contained in a variety of beyond Standard Model theories, including supersymmetric models, universal extra dimensions, or technicolor theories. If the lifetime of such a particle is long enough, the particle can…
Scalar particles that couple to two up quarks may be produced at the LHC even if they are ultraheavy, in the $8-10$ TeV mass range. A renormalizable theory that includes a diquark particle of this type ($S_{uu}$), two vectorlike quarks…
We argue for the plausibility of a broad class of vectorlike confining gauge theories at the TeV scale which interact with the Standard Model predominantly via gauge interactions. These theories have a rich phenomenology at the LHC if…
We investigate the spectacular collider signatures of macroscopically displaced, neutral particles that decay to Higgs bosons and missing energy. We show that such long-lived particles arise naturally in a very minimal extension of the…