Searcharxiv⌕ Search

arXiv · hep-ph/9903397

How fast do small x structure function rise ? A comparative analysis

Abstract

We parametrize the small x, singlet component of the proton structure function F_2 by powers and logarithms of 1/x for discrete values of Q^2 between 0.2 and 2000 GeV^2, and compare these parametrizations by applying the criterion of minimal $χ^2$. The obtained values of the fitted parameters may be used to study the evolution of F_2 in Q^2 and/or in discriminating between dynamical models. A slowing-down in the increase of F_2 towards highest available values of Q^2 is revealed. The effect is quantified in terms of the derivative ${\frac{d\ell n F_2(x,Q^2)}{d\ell n (1/x)}}$.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

P. Desgrolard, L. Jenkovszky, A. Lengyel, F. Paccanoni. 1999-03-26. How fast do small x structure function rise ? A comparative analysis. https://doi.org/10.1016/s0370-2693(99)00650-4

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Neutralino dark matter in gauge mediation

We explore the potential of neutralino dark matter within the framework of gauge-mediated supersymmetry (SUSY) breaking. Gauge mediation offers an advantage over gravity mediation, as SUSY CP/flavor problems are avoided more easily, leading to significantly milder fine-tuning for electroweak symmetry-breaking compared to gravity mediation. In our models, the lightest neutralino, as the lightest SUSY particle (LSP), is a viable dark matter candidate, assuming a gravitino mass of $\mathcal{O}(100)~\mathrm{TeV}$. The models are formulated in five-dimensional space-time, where the SUSY breaking field and the matter fields are placed on separate branes to avoid issues related to flavor and CP violation, and the radion is stabilized by a supersymmetric Goldberger--Wise mechanism. Four distinct neutralino dark matter scenarios are studied: bino-wino coannihilation, higgsino dark matter, wino dark matter, and entropy-diluted bino dark matter. For each case, we determine the allowed parameter spaces and evaluate their consistency with existing experimental limits. Additionally, we examine the potential for testing these models through future investigations at the High-Luminosity Large Hadron Collider (HL-LHC) and through dark matter direct detection experiments.

hep-ph↗

Models with rank-reducing discrete boundary conditions on $T^2/{\mathbb Z}_4$

We study six-dimensional $SU(n)$ gauge models with rank-reducing discrete boundary conditions on the orbifold $T^2/{\mathbb Z}_4$, without and with continuous Wilson line phases. For the latter case, we find that a minimal model can describe the breakdown of the electroweak symmetry based on an $SU(6)$ gauge group. This model possesses excellent features that two Higgs doublets come from the zero modes of the extra-dimensional gauge field, and the quarks in each generation can be unified into one multiplet, without exotic quarks, as the zero modes of a bulk field in the $\boldsymbol{15}$ representation of $SU(6)$. There exists a vacuum where the electroweak symmetry is slightly broken by the Hosotani mechanism, with the addition of suitable bulk fields.

hep-ph↗

Supernova cooling from neutrino-devouring dark matter

Supernova cooling provides a powerful probe of physics beyond the Standard Model (SM), in particular for new, light states interacting feebly with SM particles. In this \textit{Letter}, we investigate for the first time the production of fermionic dark matter (DM) via the neutrino-devouring process inside a core-collapse supernova, which contributes to the excessive cooling of the supernova. By incorporating state-of-the-art supernova simulation data and the full time evolution information, we derive stringent and robust limits on DM interactions, which can improve upon direct detection limits by several orders of magnitude. We exclude the cross sections down to $10^{-51}-10^{-58}$~cm$^2$ in the keV-MeV mass range for DM-electron scattering, and $10^{-49}-10^{-56}$~cm$^2$ in the 0.1-100~MeV mass range for DM-nucleon scattering, supplemented by complementary constraints from cosmology, astrophysics, colliders and direct detection experiments in the larger cross section regime. We also close almost the entire window in which fermionic DM constitutes $\mathcal{O}(1)$ fraction of DM due to its coupling to electrons in the keV-MeV mass range.

hep-ph↗