arXiv subjects

M. Zandi

Publications and source records attributed to M. Zandi.

2 recordsLinked to original sources

arXiv2026

Cosmological phase transitions: from particle physics to gravitational waves, semi-analytically

Motivated by the recent evidence of a stochastic gravitational wave background found by pulsar timing array experiments, we focus on one of the prime cosmological explanations, i.e. a supercooled first order phase transition. If confirmed, it would offer a unique opportunity to probe early Universe dynamics and the related physics beyond the Standard Model of particles and interactions. However, the prediction of the gravitational wave spectrum from a given particle physics scenario requires theoretically and computationally demanding methods. While several tools have been put forward to reduce uncertainties and automatize these computations, we study here the possibility to perform the full pipeline of computations semi-analytically in the $4D$ theory for a $U(1)^\prime$ conformal extension of the Standard Model, thus avoiding computationally intensive simulations. Our approach yields accurate results that can be used in phenomenological studies and allow for an efficient exploration of the connection between the particle physics models and their cosmological predictions.

hep-ph↗

arXiv2013

II. Non-commuting Matrix Solution of DGLAP; $F_2 {p,d}$ Data Leading to Partons Directly without Parameterization

Dominant present path for determination of quarks and gluon distribution functions from data is based on pre-assumed form of parameters. Here, an alternative direct, or non-parametric method is spelled out. As the main task, least square estimates of the central values are obtained at the exact $x$ points of the analysed ${{F_2}^{p,d}}$ data points, at a chosen $Q^2$. In the process, numerically singular system of weighted linear combination of LO decomposition equations of the data points, each at a given $(x_k, {Q_{kl}}^2), l=1, ..., n_k$, obtained from a respective $χ^2$, together with the equations of Zero Mass Variable Flavour Number constraints, are solved. In each data equation, the corresponding data points are decomposed into their quarks and gluon components, evolved from a set of unknowns at $(x_k, Q^2), k=1, ..., n$. A similar evolution is done in the constraints. As a complementary task, the constrained discrete $x$ set, required for the commuting solution of evolution equation, \cite{I}, is relaxed, and a non-commuting solution on a more natural set of exact $x$ points of the data is developed.

hep-ph↗