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Jian Zhou

Publications and source records attributed to Jian Zhou.

At least 325 records · Page 18Linked to original sources
arXiv2013

Azimuthal asymmetries for quark pair production in pA collisions

We study the azimuthal asymmetries for quark pair production in proton-nucleus collisions using a hybrid approach in which the nucleus is treated in the Color Glass Condensate (CGC) framework while the Lipatov approximation is applied on the proton side. Our treatment goes beyond the large N_c limit. We particularly focus on the so-called correlation limit where the imbalance of the transverse momentum of the quark pair is much smaller than the out-going individual quark transverse momenta. In this kinematic region, a matching between the hybrid approach and a factorization in terms of transverse momentum dependent parton distributions(TMDs) has been found. It is shown which of the various unpolarized and linearly polarized gluon TMD distributions contribute to $\cos 2 ϕ$ and $\cos 4 ϕ$ modulations of quark pair production.

hep-ph↗
arXiv2013

Transverse single spin asymmetry in hadronic $η_{c,b}$ production

We study the transverse single spin asymmetry in $η_{c,b}$ production in polarized hadron collisions, employing the collinear twist-3 approach in combination with the color singlet model. Our main focus lies on the contribution from the twist-3 Efremov-Teryaev-Qiu-Sterman function. By extrapolating the derived spin dependent cross section to the small transverse momentum region, consistency between the collinear twist-3 approach and the transverse momentum dependent factorization approach is confirmed. As a byproduct of this work, we identify a term contributing to the scale evolution of tri-gluon correlations in the flavor-singlet case which was previously missed.

hep-ph↗
arXiv2012

Gopakumar-Vafa BPS invariants, Hilbert schemes and quasimodular forms. I

We prove a closed formula for leading Gopakumar- Vafa BPS invariants of local Calabi-Yau geometries given by the canonical line bundles of toric Fano surfaces. It shares some similar features with Goettsche-Yau-Zaslow formula: Connection with Hilbert schemes, connection with quasimodular forms, and quadratic property after suitable transformation. In Part I of this paper we will present the case of projective plane, more general cases will be presented in Part II.

math.AG↗
arXiv2012

Higgs boson production in high energy proton-nucleus collisions

We study Higgs boson production from gluon-gluon fusion at mid-rapidity in high energy proton-nucleus collisions. For this process the presently still little known gluon distribution function $h_1^{\perp g}$ gives a numerically relevant contribution. We show by explicite calculation that using CGC (color glass condensate) model input the result obtained in the naive k_t factorization approach matches the result obtained in the TMD factorization framework for a dilute medium. We also verify the earlier finding that the k_t factorization formalism for Higgs production breaks down in a dense medium. In doing so we formulate a hybrid model which allows one to treat such reactions theoretically.

hep-ph↗
arXiv2012

Fermionic gluing principle of the topological vertex

We will establish the fermionic gluing principle of the topological vertex, that is, provided the framed ADKMV conjecture, the generating functions of the Gromov-Witten invariants of all toric Calabi-Yau threefolds are Bogoliubov transforms of the vacuum.

math.AG↗
arXiv2012

A note on the scale evolution of the ETQS function T_F(x,x)

We reexamine the scale dependence of the ETQS (Efremov-Teryaev-Qiu-Sterman) twist-3 matrix element which has been studied already by the four different groups with conflicting results Ref.[1-4]. We find that we can in fact reproduce the results of Ref.[4] with the method Ref.[4] when we treat some subtleties with greater care, thus easing the mentioned conflict.

hep-ph↗
arXiv2012

Double spin asymmetry A_{LT} in direct photon production

We study the longitudinal-transverse double spin asymmetry $A_{LT}$ for direct photon production in nucleon-nucleon scattering by using the collinear twist-3 approach. This asymmetry, which, for instance, could be measured at RHIC, contains a complete set of collinear twist-3 correlation functions in a transversely polarized nucleon.

hep-ph↗
arXiv2011

Exclusive production of quarkonia as a probe of the GPD E for gluons

Exclusive quarkonium photo- and electro-production off the nucleon is studied in the framework of generalized parton distributions (GPDs). The short distance part of the process is treated at leading order in perturbative Quantum Chromodynamics. The main focus is on the GPD E for gluons. On the basis of different models for E we estimate the transverse target spin asymmetry for typical kinematics of a future Electron Ion Collider. We also explore the potential of measuring the polarization of the recoil nucleon.

hep-ph↗
arXiv2011

Azimuthal asymmetry in SIDIS off nuclei as probe for $\hat q$

The energy loss parameter $\hat q$ is one of the fundamental transport parameters of hadronic matter. Using the twist-4 collinear approach, we show that the $\cos ϕ$ azimuthal asymmetry in unpolarized semi-inclusive deeply inelastic scattering (SIDIS) off a large nucleus at intermediate transverse momentum is a sensitive observable for its determination. The effect is due to the suppression of the azimuthal asymmetry by final-state multiple scattering.

hep-ph↗
arXiv2011

Biomolecular Filters for Improved Separation of Output Signals in Enzyme Logic Systems Applied to Biomedical Analysis

Biomolecular logic systems processing biochemical input signals and producing "digital" outputs in the form of YES/NO were developed for analysis of physiological conditions characteristic of liver injury, soft tissue injury and abdominal trauma. Injury biomarkers were used as input signals for activating the logic systems. Their normal physiological concentrations were defined as logic-0 level, while their pathologically elevated concentrations were defined as logic-1 values. Since the input concentrations applied as logic 0 and 1 values were not sufficiently different, the output signals being at low and high values (0, 1 outputs) were separated with a short gap making their discrimination difficult. Coupled enzymatic reactions functioning as a biomolecular signal processing system with a built-in filter property were developed. The filter process involves a partial back-conversion of the optical-output-signal-yielding product, but only at its low concentrations, thus allowing the proper discrimination between 0 and 1 output values.

cond-mat.soft↗
arXiv2011

Distribution of linearly polarized gluons inside a large nucleus

The distribution of linearly polarized gluons inside a large nucleus is studied in the framework of the color glass condensate. We find that the Weizsäcker-Williams distribution saturates the positivity bound at large transverse momenta and is suppressed at small transverse momenta, whereas the dipole distribution saturates the bound for any value of the transverse momentum. We also discuss processes in which both distributions of linearly polarized gluons can be probed.

hep-ph↗
arXiv2011

Noether's problem for some 2-groups

Let $G$ be a finite group and $k$ be a field. Let $G$ act on the rational function field $k(x_g:g\in G)$ by $k$-automorphisms defined by $g\cdot x_h=x_{gh}$ for any $g,h\in G$. Noether's problem asks whether the fixed field $k(G)=k(x_g:g\in G)^G$ is rational (i.e. purely transcendental) over $k$. We will prove that, if $G$ is a group of order $2^n$ ($n\ge 4$) and of exponent $2^e$ such that (i) $e\ge n-2$ and (ii) $ζ_{2^{e-1}} \in k$, then $k(G)$ is $k$-rational.13A50,14E08,14M20,12F12

math.AG↗
arXiv2011

Noether's problem for the groups with a cyclic subgroup of index 4

Let $G$ be a finite group and $k$ be a field. Let $G$ act on the rational function field $k(x_g:g\in G)$ by $k$-automorphisms defined by $g\cdot x_h=x_{gh}$ for any $g,h\in G$. Noether's problem asks whether the fixed field $k(G)=k(x_g:g\in G)^G$ is rational (i.e. purely transcendental) over $k$. Theorem 1. If $G$ is a group of order $2^n$ ($n\ge 4$) and of exponent $2^e$ such that (i) $e\ge n-2$ and (ii) $ζ_{2^{e-1}} \in k$, then $k(G)$ is $k$-rational. Theorem 2. Let $G$ be a group of order $4n$ where $n$ is any positive integer (it is unnecessary to assume that $n$ is a power of 2). Assume that {\rm (i)} $\fn{char}k \ne 2$, $ζ_n \in k$, and {\rm (ii)} $G$ contains an element of order $n$. Then $k(G)$ is rational over $k$, except for the case $n=2m$ and $G \simeq C_m \rtimes C_8$ where $m$ is an odd integer and the center of $G$ is of even order (note that $C_m$ is normal in $C_m \rtimes C_8$) ; for the exceptional case, $k(G)$ is rational over $k$ if and only if at least one of $-1, 2, -2$ belongs to $(k^{\times})^2$.

math.AC↗
arXiv2011

Exploring the structure of the proton through polarization observables in l p \to jet X

We present results for a complete set of polarization observables for jet production in lepton proton collision, where the final state lepton is not observed. The calculations are carried out in collinear factorization at the level of Born diagrams. For all the observables we also provide numerical estimates for typical kinematics of a potential future Electron Ion Collider. On the basis of this numerical study, the prospects for the transverse single target spin asymmetry are particularly promising. This observable is given by a certain quark-gluon correlation function, which has a direct relation to the transverse momentum dependent Sivers parton distribution.

hep-ph↗
arXiv2011

Evidence that the upper critical field of Nb3Sn is independent of whether it is cubic or tetragonal

Although 2011 marks the 50th anniversary of Nb3Sn as the first high field superconductor, real understanding of its upper critical field behavior μ0Hc2 is incomplete. Here we show surprising μ0Hc2 data on highly homogeneous bulk samples examined both by small-current, transport and by volumetric-averaging specific heat and the reversible magnetization techniques, which exhibit identical upper critical field μ0Hc2(0.3 K) ~ 29{\pm} 0.2 T with or without undergoing the cubic to tetragonal transition, a result in strong contrast to widely used multiple-source data compilations that show a strong depression of μ0Hc2(0K) from 29 T to 21.4 T in the tetragonal state.

cond-mat.supr-con↗
arXiv2011

Dihadron fragmentation functions for large invariant mass

Using perturbative Quantum Chromodynamics, we compute dihadron fragmentation functions for a large invariant mass of the dihadron pair. The main focus is on the interference fragmentation function $H_1^{\open}$, which plays an important role in spin physics of the nucleon. Our calculation also reveals that $H_1^{\open}$ and the Collins fragmentation function have a closely related underlying dynamics. By considering semi-inclusive deep-inelastic scattering, we further show that collinear factorization in terms of dihadron fragmentation functions, and collinear factorization in terms of single hadron fragmentation functions provide the same result in the region of intermediate invariant mass.

hep-ph↗