Electron heating and acceleration by magnetic reconnection in hot accretion flows (2009)
Ding, Jian, Yuan, Feng, Liang, Edison
Both analytical and numerical works show that magnetic reconnection must occur in hot accretion flows. This process will effectively heat and accelerate electrons. In this paper we use the numerical...
Reprocessed emission from warped accretion discs induced by Bardeen-Petterson effect (2009)
Wu, Sheng-Miao, Chen, Lei, Yuan, Feng
The broad Balmer emission line profiles resulting from reprocessing of UV/X-ray radiation from a warped accretion disc induced by Bardeen-Petterson effect are studied in this paper. We adopt a thin...
Transverse momentum dependent quark distributions and polarized Drell-Yan processes (2009)
Zhou, Jian, Yuan, Feng, Liang, Zuo-Tang
We study the spin-dependent quark distributions at large transverse momentum. We derive their transverse momentum behaviors in the collinear factorization approach in this region. We further...
Monte Carlo simulations of global Compton cooling in inner regions of hot accretion flows (2009)
Xie, Fu-Guo, Niedzwiecki, Andrzej, Zdziarski, Andrzej A., Yuan, Feng
Hot accretion flows such as advection-dominated accretion flows are generally optically thin in the radial direction. Thus photons generated at some radii can cool or heat electrons at other radii...
Semi-inclusive Deep Inelastic Scattering at small x (2009)
Marquet, Cyrille, Xiao, Bo-Wen, Yuan, Feng
We study the semi-inclusive hadron production in deep inelastic scattering at small $x$. A transverse momentum dependent factorization is found consistent with the results calculated in the small-$x$...
Collins Fragmentation and the Single Transverse Spin Asymmetry (2009)
We study the Collins mechanism for the single transverse spin asymmetry in the collinear factorization approach. The correspondent twist-three fragmentation function is identified. We show that the...
Steady state solution of warped accretion discs (2009)
Chen, Lei, Wu, Shengmiao, Yuan, Feng
We consider a thin accretion disc warped due to the Bardeen-Petterson effect, presenting both analytical and numerical solutions for the situation that the two viscosity coefficients vary with radius...
We calculate the next-to-leading order perturbative QCD corrections to the transverse momentum weighted single transverse spin asymmetry in Drell-Yan lepton pair production in hadronic collisions. We...
Collins Fragmentation and the Single Transverse Spin Asymmetry (2009)
We study the Collins mechanism for the single transverse spin asymmetry in the collinear factorization approach. The correspondent twist-three fragmentation function is identified. We show that the...
Revisiting the "Fundamental Plane" of Black Hole Activity at Extremely Low Luminosities (2009)
Yuan, Feng, Yu, Zhaolong, Ho, Luis C.
We investigate the origin of the X-ray emission in low-luminosity AGNs (LLAGNs). Yuan & Cui (2005) predicted that the X-ray emission should originate from jets rather than from an advection-dominated...
Practicality of Asymmetric Fingerprinting for Digital Data (2009)
Feng Yuan, Supervisor Tina Lindgren, Feng Yuan
The idea of fingerprinting of digital data has been around for some time. The principal goal behind this concept is to deter people from distributing illegal copies and therefore allow the original...
Theoretical Overview on Recent Developments in Transverse Spin Physics (2009)
Transverse-spin physics has been very active and rapidly developing in the last few years. In this talk, I will briefly summarize recent theoretical developments, focusing on the associated QCD...
Drell-Yan Lepton Pair Azimuthal Asymmetry in Hadronic Processes (2009)
Zhou, Jian, Yuan, Feng, Liang, Zuo-tang
We study the azimuthal asymmetry in the Drell-Yan lepton pair production in hadronic scattering processes at moderate transverse momentum region, taking into account the contributions from the...
Transverse Spin Physics: Recent Developments (2009)
Transverse-spin physics has been very active and rapidly developing in the last few years. In this talk, I will briefly summarize recent theoretical developments, focusing on the associated QCD...
Recent Development in Proton Spin Physics (2009)
In the naive model of the proton, its 1/2 spin is carried by its quark constituents. However, experiments over the last several decades have shown that the quark spin only contribute a small portion...
QCD Evolution of the Transverse Momentum Dependent Correlations (2008)
Zhou, Jian, Yuan, Feng, Liang, Zuo-Tang
We study the QCD evolution for the twist-three quark-gluon correlation functions associated with the transverse momentum odd quark distributions. Different from that for the leading twist quark...
A Magnetohydrodynamic Model for the Formation of Episodic Jets (2008)
Yuan, Feng, Lin, Jun, Wu, Kinwah, Ho, Luis C.
Episodic ejection of plasma blobs have been observed in many black hole systems. While steady, continuous jets are believed to be associated with large-scale open magnetic fields, what causes the...
Kang, Zhong-Bo, Qiu, Jian-Wei, Vogelsang, Werner, Yuan, Feng
We calculate the single transverse-spin asymmetry for open charm production in $pp$ collisions within the QCD collinear factorization approach. We include contributions from both twist-three...
Self-Similar Solution of Hot Accretion Flows with Ordered Magnetic Field and Outflow (2008)
Bu, De-Fu, Yuan, Feng, Xie, Fu-Guo
Observations and numerical magnetohydrodynamic (MHD) simulations indicate the existence of outflows and ordered large-scale magnetic fields in the inner region of hot accretion flows. In this paper...
Origin of the X-ray Emission in the Nuclei of FR Is (2008)
Wu, Qingwen, Yuan, Feng, Cao, Xinwu
We investigate the X-ray origin in FRIs using the multi-waveband high resolution data of eight FR I sources, which have very low Eddington ratios. We fit their multi-waveband spectrum using a coupled...
Hyperon Polarization in Unpolarized Scattering Processes (2008)
Zhou, Jian, Yuan, Feng, Liang, Zuo-Tang
Transverse polarization in the Hyperon production in the unpolarized deep inelastic scattering and pp collisions is studied in the twist-three approach, considering the contribution from the...
Collins Asymmetry at Hadron Colliders (2008)
We study the Collins effect in the azimuthal asymmetric distribution of hadrons inside a high energy jet in the single transverse polarized proton proton scattering. From the detailed analysis of...
Heavy Quarkonium Production in Single Transverse Polarized High Energy Scattering (2008)
We formulate the single transverse spin asymmetry in heavy quarkoniumproduction in lepton-nucleon and nucleon-nucleon collisionsin the non-relativistic limit. We findthat the asymmetry is very...
Spin-resolved impurity resonance states in electron-doped cuprate superconductors (2008)
Liu, Bin, Liang, Ying, Yuan, Feng
This paper has been withdrawn by the author due to some insufficient discussions on Fig. 3.
Origin of X-ray Emission from Transient Black Hole Candidates in Quiescence (2008)
Pszota, Gabor, Zhang, Hui, Yuan, Feng, Cui, Wei
We report results from a systematic study of X-ray emission from black hole transients in quiescence. In this state mass accretion is thought to follow the geometry of an outer optically thick,...
Single Spin Asymmetries in Heavy Quark and Antiquark Productions (2008)
The single transverse spin asymmetries in heavy quark and anti-quark production from the quark-antiquark annihilation channel contribution is studied by taking into account the initial and final...
Azimuthal Asymmetric Distribution of Hadrons Inside a Jet at Hadron Collider (2008)
We study the azimuthal asymmetric distribution of hadrons inside a high energy jet in the single transverse polarized proton proton scattering, coming from the Collins effect multiplied by the quark...
On the Relation Between Mechanisms for Single-Transverse-Spin Asymmetries (2008)
Koike, Yuji, Vogelsang, Werner, Yuan, Feng
Recent studies have shown that two widely-used mechanisms for single-transverse-spin asymmetries based on either twist-three contributions or on transverse-momentum-dependent (Sivers) parton...
Single Spin Asymmetry in Inclusive Hadron Production in pp Scattering from Collins Mechanism (2008)
We study the Collins mechanism contribution to the single transverse spin asymmetry in inclusive hadron production in pp scattering p^{\uparrow}p\to \pi X from the leading jet fragmentation. The...
Re-Examining the Use of Network-on-Chip as Test Access Mechanism (2008)
Feng Yuan, Lin Huang, Qiang Xu
Existing work on testing NoC-based systems advocates to reuse the on-chip network itself as test access mechanism (TAM) to transport test data to/from embedded cores. While this methodology obviously...
Global Compton heating and cooling in hot accretion flows (2008)
Yuan, Feng, Xie, Fuguo, Ostriker, Jeremiah P.
The hot accretion flow is usually optically thin in the radial direction, therefore the photons produced at one radius can travel for a long distance without being absorbed. These photons thus can...
NGC 4258: a jet-dominated low-luminosity AGN? (2008)
Feng Yuan, Sera Markoff, Heino Falcke, Peter L. Biermann
Low-luminosity AGNs (LLAGNs) are a very important class of sources since they occupy a significant fraction of local galaxies. Their spectra differ significantly from the canonical luminous AGNs,...
Heavy Quarkonium Production in Single Transverse Polarized High Energy Scattering (2008)
We formulate the single transverse spin asymmetry in heavy quarkonium production in lepton-nucleon and nucleon-nucleon collisions in the non-relativistic limit. We find that the asymmetry is very...
Collins Asymmetry at Hadron Colliders (2008)
We study the Collins effect in the azimuthal asymmetric distribution of hadrons inside a high energy jet in the single transverse polarized proton proton scattering. From the detailed analysis of...
The Nature of the 10 Kilosecond X-ray Flare in Sgr A* (2007)
Sera Markoff, Heino Falcke, Feng Yuan, Peter L. Biermann
The X-ray mission Chandra has observed a dramatic X-ray are { a brightening by a factor of 50 for only three hours { from Sgr A*, the Galactic Center supermassive black hole. Sgr A* has never shown...
On the Relation Between Mechanisms for Single-Transverse-Spin Asymmetries (2007)
Koike, Yuji, Vogelsang, Werner, Yuan, Feng
Recent studies have shown that two widely-used mechanisms for single-transverse-spin asymmetries based on either twist-three contributions or on transverse-momentum-dependent (Sivers) parton...
Azimuthal Asymmetric Distribution of Hadrons Inside a Jet at Hadron Collider (2007)
We study the azimuthal asymmetric distribution of hadrons inside a high energy jet in the single transverse polarized proton proton scattering, coming from the Collins effect multiplied by the quark...
Hadronic Dijet Imbalance and Transverse-Momentum Dependent Parton Distributions (2007)
We compare several recent theoretical studies of the single transverse spin asymmetry in dijet-correlations at hadron colliders. We show that the results of these studies are all consistent. To...
Single Transverse-Spin Asymmetry in Hadronic Dijet Production (2007)
Qiu, Jian-Wei, Vogelsang, Werner, Yuan, Feng
We study the single transverse-spin asymmetry for dijet production in hadronic collisions in both the collinear QCD factorization approach and the Brodsky-Hwang-Schmidt model. We show that a...
Effect of Orbital Angular Momentum on Valence-Quark Helicity Distributions (2007)
Avakian, Harut, Brodsky, Stanley J., Deur, Alexandre, Yuan, Feng
We study the quark helicity distributions at large x in perturbative QCD, taking into account contributions from the valence Fock states of the nucleon which have nonzero orbital angular momentum....
Asymmetric Di-jet Production in Polarized Hadronic Collisions (2007)
Qiu, Jian-Wei, Vogelsang, Werner, Yuan, Feng
Using the collinear QCD factorization approach, we study the single-transverse-spin dependent cross section Delta sigma(S_perp) for the hadronic production of two jets of momenta P_1=P+q/2 and...
Black Hole Shadow Image and Visibility Analysis of Sagittarius A* (2007)
Huang, Lei, Cai, Mike, Shen, Zhi-Qiang, Yuan, Feng
The compact dark objects with very large masses residing at the centres of galaxies are believed to be black holes. Due to the gravitational lensing effect, they would cast a shadow larger than their...
Accretion Disk Spectra of the Brightest Ultra-luminous X-ray Source in M82 (2006)
Yuan, Feng, Wu, Xue-Bing, Xue, Yongquan
Emission spectra of hot accretion disks characteristic of advection dominated accretion flow (ADAF) models are investigated for comparison with the brightest ultra-luminous source, X-1, in the galaxy...
Single Transverse-Spin Asymmetries at Large-x (2006)
Brodsky, Stanley J., Yuan, Feng
The large-$x$ behavior of the transverse-momentum dependent quark distributions is analyzed in the factorization-inspired perturbative QCD framework, particularly for the naive time-reversal-odd...
Single transverse-spin asymmetry in high transverse momentum pion production in pp collisions (2006)
Kouvaris, Chris, Qiu, Jian-Wei, Vogelsang, Werner, Yuan, Feng
We study the single-spin (left-right) asymmetry in single-inclusive pion production in hadronic scattering. This asymmetry is power-suppressed in the transverse momentum of the produced pion and can...
Idilbi, Ahmad, Ji, Xiangdong, Yuan, Feng
We apply the effective field theoretic (EFT) approach to resum the large perturbative logarithms arising when partonic hard scattering cross-sections are taken to the threshold limit. We consider...
X-ray Spectral Variability of TeV Blazars during Rapid Flares (2006)
Xue, Yongquan, Yuan, Feng, Cui, Wei
The spectral energy distribution (SED) of TeV blazars peaks both at keV and TeV energies. The X-ray emission is generally believed to originate in the synchrotron emission from relativistic electrons...
Single-Transverse Spin Asymmetry in Semi-Inclusive Deep Inelastic Scattering (2006)
Ji, Xiangdong, Qiu, Jian-Wei, Vogelsang, Werner, Yuan, Feng
We study the single-transverse spin asymmetry in semi-inclusive hadron production in deep inelastic scattering. We derive the leading contribution to the asymmetry at moderate transverse momentum...
Ji, Xiangdong, Qiu, Jianwei, Vogelsang, Werner, Yuan, Feng
We study the single-transverse spin asymmetry for the Drell-Yan process. We consider production of the lepton pair at large transverse momentum, $q_\perp\sim Q$, where $Q$ is the pair's mass. The...
Testing RIAF model for Sgr A* using the size measurements (2006)
Yuan, Feng, Shen, Zhi-Qiang, Huang, Lei
Recent radio observations by the VLBA at 7 and 3.5 mm produced the high-resolution images of the compact radio source located at the center of our Galaxy--Sgr A*, and detected its...
A Unified Picture for Single Transverse-Spin Asymmetries in Hard Processes (2006)
Ji, Xiangdong, Qiu, Jian-Wei, Vogelsang, Werner, Yuan, Feng
Using Drell-Yan pair production as an example, we explore the relation between two well-known mechanisms for single transverse-spin asymmetries in hard processes: twist-three quark-gluon correlations...
Single-Transverse Spin Asymmetries: From DIS to Hadronic Collisions (2005)
We study single-spin asymmetries in semi-inclusive deep inelastic scattering with transversely polarized target. Based on the QCD factorization approach, we consider Sivers and Collins contributions...
Ji, Xiangdong, Ma, Jian-Ping, Yuan, Feng
We study transverse-momentum-dependent (TMD) gluon distributions and factorization theorems for the gluon-initiated semi-inclusive processes at hadron colliders. Gauge-invariant TMD gluon...
Photoproduction of $\eta_c$ in NRQCD (1999)
Hao, Li-Kun, Yuan, Feng, Chao, Kuang-Ta
We present a calculation for the photoproduction of $\eta_c$ under the framework of NRQCD factorization formalism. We find a quite unique feature that the color-singlet contribution to this process...
Quarkonium production in SM Higgs decays (1998)
Qiao, Cong-Feng, Yuan, Feng, Chao, Kuang-Ta
We investigate the SM Higgs decays into heavy quarkonia J/\psi and \Upsilon in both color-singlet and color-octet mechanisms. It is found that in J/\psi production the contribution through...
High-$p_T$ $\psi\psi$ production as signals for Double Parton scattering at hadron colliders (1997)
We present an analysis of the \psi\psi production from double parton (DP) sacttering and single parton (SP) scattering in the large p_T region via color-octet gluon fragmentation. We find that at the...