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Guanghua Xu

Publications and source records attributed to Guanghua Xu.

6 recordsLinked to original sources
arXiv2026

Sign Reversal of Boer-Mulders Functions from Semi-inclusive Deep-Inelastic Scattering to the Drell-Yan Process

A striking prediction of QCD on the properties of the novel Transverse Momentum Dependent (TMD) distribution functions is that the time-reversal odd Sivers and Boer-Mulders functions extracted from semi-inclusive deep-inelastic scattering (SIDIS) will undergo a sign reversal in the Drell-Yan (DY) process. This prediction has been tested by experiments that have focused on the Sivers functions so far. We examine the current status on the theoretical prediction and experimental extraction of the signs of the Boer-Mulders functions from SIDIS and DY. We show that the existing SIDIS and DY data are consistent with the predicted sign reversal of the Boer-Mulders functions for proton's valence quark distribution. Prospects for future experiments at EIC capable of testing the sign reversal of the pion Boer-Mulders functions are also discussed.

hep-ph↗
arXiv2019

Simultaneous induction of SSMVEP and SMR Using a Gaiting video stimulus: a novel hybrid brain-computer interface

We proposed a novel visual stimulus for brain-computer interface. The stimulus is in the form gaiting sequence of a human. The hypothesis is that observing such a visual stimulus would simultaneously induce 1) steady-state motion visual evoked potential (SSMVEP) in the occipital area, similarly to an SSVEP stimulus; and 2) sensorimotor rhythm (SMR) in the primary sensorimotor area, because such action observation (AO) could activate the mirror neuron system. Canonical correlation analysis (CCA) was used to detect SSMVEP from occipital EEG, and event-related spectral perturbations (ERSP) were used to identify SMR in the EEG from the sensorimotor area. The results showed that the proposed visual gaiting stimulus-induced SSMVEP, with classification accuracies of 88.9 $\pm$ 12.0% in a four-class scenario. More importantly, it induced clear and sustained event-related desynchronization/synchronization (ERD/ERS) in the EEG from the sensorimotor area, while no ERD/ERS in the sensorimotor area could be observed when the other two SSVEP stimuli were used. Further, for participants with sufficiently clear SSMVEP pattern (classification accuracy > 85%), the ERD index values in mu-beta band induced by the proposed gaiting stimulus were statistically different from that of the other two types of stimulus. Therefore, a novel BCI based on the proposed stimulus has potential in neurorehabilitation applications because it simultaneously has the high accuracy of an SSMVEP (~90% accuracy in a four-class setup) and the ability to activate sensorimotor cortex. And such potential will be further explored in future studies.

eess.SP↗
arXiv2009

Searching for a New Source(s) of T-Violation in Spin Dependent Total Cross Section Measurements

We first re-prove with a more complete method that the the minimum standard model, with the inclusion of the CKM-matrix, requires the T-odd/P-odd total cross section of two spin-1/2 particles to vanish in all orders\cite{gxu}. Then we study the contribution to T-odd/P-odd total scattering cross sections from various channels within the Higgs sector, and optimize conditions for possible experimental measurements of these effects. These studies show that such contributions can appear at tree level, and that the spin dependent cross section asymmetry is measurable if the lightest Higgs paarticle is not too massive, {\it e.g.} $m_H \sim 200 GeV$, and if suitable reaction channels and beam energies and luminosities are chosen.

hep-ph↗
arXiv2005

Higher Twist Effects in Parton Fragmentation Functions

We study twist expansions for parton fragmentation functions based on the definition of the twist as an invariant matrix element of a light-cone, bilocal operator. The results are then applied to a method which might be used to extract higher twist effects in the fragmentation sector using both $e^+ e^-$, and $e^- p$ collisions. We discuss how to apply the later measurements to experiments at the Jefferson National Acceleration Facility.

nucl-th↗
arXiv1999

Mass Differences within Isotopic Multiplets in a SUSY Electro-weak Theory

Based on the idea that electromagnetism is responsible for the mass differences within isotopic multiplets, and possibly also for the whole mass of the electron, a supersymmetric gauge theoretical model based on the group $SU(2)_{L} \times SU(2)_{R} \times U(1)_{Y}$ is constructed. Under some reasonable assumptions to the SUSY particle spectrum, a correct sign for the mass difference within an isotopic multiplet is obtained. This might provide a possible scenario to understand the old puzzle of the proton-neutron mass difference.

hep-ph↗