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H. -C. Cheng

Publications and source records attributed to H. -C. Cheng.

7 recordsLinked to original sources
arXiv2025

ECFA Higgs, electroweak, and top Factory Study

The ECFA Higgs, electroweak, and top Factory Study ran between 2021 and 2025 as a broad effort across the experimental and theoretical particle physics communities, bringing together participants from many different proposed future collider projects. Activities across three main working groups advanced the joint development of tools and analysis techniques, fostered new considerations of detector design and optimisation, and led to a new set of studies resulting in improved projected sensitivities across a wide physics programme. This report demonstrates the significant expansion in the state-of-the-art understanding of the physics potential of future e+e- Higgs, electroweak, and top factories, and has been submitted as input to the 2025 European Strategy for Particle Physics Update.

hep-ex↗
arXiv2014

Low-energy trions in graphene quantum dots

We investigate, within the envelope function approximation, the low-energy states of trions in graphene quantum dots. The presence of valley pseudospin in graphene as an electron degree of freedom apart from spin adds convolution to the interplay between exchange symmetry and the electron-electron interaction in the trion, leading to new states of trions as well as a low energy trion spectrum different from those in semiconductors. Due to the involvement of valley pseudospin, it is found that the low-energy spectrum is nearly degenerate and consists of states all characterized by having an antisymmetric (pseudospin) (spin) component in the wave function, with the spin (pseudospin) part being either singlet (triplet) or triplet (singlet), as opposed to the spectrum in a semiconductor whose ground state is known to be nondegenerate and always a spin singlet in the case of X- trions. We investigate trions in the various regimes determined by the competition between quantum confinement and electron-electron interaction, both analytically and numerically. The numerical work is performed within a variational method accounting for electron mass discontinuity across the QD edge. The result for electron-hole correlation in the trion is presented. Effects of varying quantum dot size and confinement potential strength on the trion binding energy are discussed.

cond-mat.mes-hall↗
arXiv2001

Deconstructing Gaugino Mediation

We present a model of supersymmetry breaking which produces gaugino masses and negligible scalar masses at a high scale. The model is inspired by ``deconstructing'' or ``latticizing'' models in extra dimensions where supersymmetry breaking and visible matter are spatially separated. We find a simple four-dimensional model which only requires two lattice sites (or gauge groups) to reproduce the phenomenology.

hep-ph↗
arXiv1996

Probing Lepton Flavor Violation at Future Colliders

Supersymmetric theories with significant lepton flavor violation have $\tilde{e}$ and $\tildeμ$ nearly degenerate. In this case, pair production of $\tilde{e}^+ \tilde{e}^-$ and $\tildeμ^+ \tildeμ^-$ at LEPII and at the Next Linear Collider leads to the phenomenon of slepton oscillations, which is analogous to neutrino oscillations. The reach in $Δm^2$ and $\sin^2 2 θ$ gives a probe of lepton flavor violation which is significantly more powerful than the current bounds from rare processes, such as $μ\to eγ$. Polarizable $e^-$ beams and the $e^-e^-$ mode at the NLC are found to be promising options.

hep-ph↗
arXiv1994

Squark and Slepton Mass Relations in Grand Unified Theories

In the minimal supersymmetric standard model, assuming universal scalar masses at large energies, there are four intragenerational relations between the masses of the squarks and sleptons for each light generation. In this paper we study the scalar mass relations which follow only from the assumption that at large energies there is a grand unified theory which leads to a significant prediction of the weak mixing angle. Two new intragenerational mass relations for each of the light generations are derived. In addition, a third mass relation is found which relates the Higgs masses, the masses of the third generation scalars , and the masses of the scalars of the lighter generations. Verification of a fourth mass relation, involvingonly the charged slepton masses, provides a signal for SO(10) unification.

hep-ph↗
arXiv1993

$SO(10)$ Operator Analysis For $ν_μν_τ$ Oscillations

In grand unified theories the flavor mixing angles of leptons are related to those of quarks. In this paper we study SO(10) theories with a precise group theoretic relation at the GUT scale for mixing between the heaviest two generations: $\thetuto = κ\abs{\vcbo}$. A comprehensive operator search yields all possible cases where $κ$ is a group theory Clebsch. The resulting predictions for $ν_μν_τ$ oscillations are scaled from the grand to the weak scales. We find that all but one of the models which have such a relationship between $\thetuto$ and $\vcbo$, and are not already excluded, will be probed by the CHORUS and NOMAD experiments. A more precise mixing measurement, for example by the proposed P803 experiment, could distinguish between the models.

hep-ph↗