arXiv subjects

Ali Shayegan Shirazi

Publications and source records attributed to Ali Shayegan Shirazi.

3 recordsLinked to original sources

arXiv2024

Multi-Scalar Production At Large Center-Of-Mass Energy

In quantum field theory, the probability of producing scalar particles grows factorially as a function of the number of the particles produced. This poses a problem theoretically, in maintaining unitarity, and is counter-intuitive phenomenologically. The factorial growth is a byproduct of the perturbation theory, but has been found in some of the semi-classical and non-perturbative calculations as well. Recently, it has been proposed that the factorial growth might be observable in the future 100 TeV hadron collider. After reviewing some of the past calculations, we analyze the cancelation of IR divergences to find Altarelli-Parisi function and the Sudakov form factor. We then use these to write an equation for the generating function of scalar jet rates. We further argue that we can turn the jet rates into particle cross section by swapping the opening angle with particle mass. We will present our results for $ϕ^3$ theory in four and six spacetime dimensions, and $ϕ^4$ in four spacetime dimensions. We find that, while the final particles are relativistic, the cross sections do not grow factorially.

hep-ph↗

arXiv2020

Quantum Critical Higgs: From AdS$_5$ to Colliders

We examine distinctive signatures of Quantum Critical Higgs models at the LHC and future higher energy colliders. In these models the Higgs boson is part of a conformal sector that is softly broken at a threshold scale, and generically the scaling dimension of the Higgs is larger than in the Standard Model. In particular we examine the $gg\to H \to ZZ$, $gg\to H\to γγ$, and $gg\to Z\to HZ$ channels to see how the cross sections deviate from the Standard Model in the high invariant mass region. In order to perform the calculations we use 5D duals of Quantum Critical Higgs models using the AdS/CFT correspondence, with a soft wall to break the conformal symmetry.

hep-ph↗

arXiv2019

Collider Phenomenology of a Gluino Continuum

Continuum supersymmetry is a class of models in which the supersymmetric partners together with part of the standard model come from a conformal sector, broken in the IR near the TeV scale. Such models not only open new doors for addressing the problems of the standard model, but also have unique signatures at hadron colliders, which might explain why we have not yet seen any superpartners at the LHC. Here we use gauge-gravity duality to model the conformal sector, generate collider simulations, and finally analyze continuum gluino signatures at the LHC. Due to the increase in the number of jets produced the bounds are weaker than for the minimal supersymmetric standard model with the same gluino mass threshold.

hep-ph↗