arXiv subjects

Xurong Chen

Publications and source records attributed to Xurong Chen.

At least 145 records · Page 8Linked to original sources

arXiv2017

Coherent photoproductions of $J/Ψ$ and $Υ$ mesons in pp and PbPb ultraperipheral collisions from dynamical gluon distribution

We present calculations of coherent photoproduction of vector mesons ($J/Ψ$ and $Υ$) with leading-order parton distribution functions to check new kinds of corrections of the DGLAP equations and nuclear modifications. The input gluon distribution of the proton is the dynamical parton model from the DGLAP equations with GLR-MQ-ZRS (Gribov-Levin-Ryskin, Mueller-Qiu, Zhu-Ruan-Shen) modifications. From comparison between several other gluon distribution models, we find that the dynamical gluon distribution fits with the results of meson photoproduction experiments in the high energy region. The calculation of the differential cross sections using dynamical and other gluon distributions is compared with the experimental data from the HERA, ZEUS and LHCb Collaborations. Although there is little data for the rapidity distribution of vector meson photoproduction near zero rapidity, the dynamical gluon distribution works well with the data in the large rapidity region.

hep-ph↗

arXiv2017

Estimating proton radius and proportion of other non-perturbative components in the proton by the Maximum Entropy Method

In this paper, we apply the Maximum Entropy Method to estimate the proton radius and determine the valence quark distributions in the proton at extremely low resolution scale Q$^{2}_{0}$. Using the simplest functional form of the valence quark distribution and standard deviations of quark distribution functions in the estimation of the proton radius, we obtain a quadratic polynomial for the relationship between the proton radius and the momentum fraction of other non-perturbative components in the proton. The proton radii are approximately equal to the muonic hydrogen experimental result $r_p$ = 0.841~fm and the CODATA analysis $r_p$ = 0.877 fm when the other non-perturbative components account for 17.5\% and 22.3\% respectively. We propose $"ghost~~matter"$ to explain the difference in other non-perturbative components (4.8\%) that the electron can detect.

hep-ph↗

arXiv2017

Confining potential of Y-string on the lattice at finite T

The potential due to a system of three static quark (3Q) is studied using SU(3) lattice QCD at finite temperature with Polyakov loops operators. We focused our analysis on the large distance properties of the 3Q potential and found a good fit behavior to the Y-string model formula. In addition to the linearly confining term proportional to the minimal length of the Y-string, we observed that the subleading logarithmic term, which is proportional to Dedekind eta function and accounts for the Y-string's quantum fluctuations, is necessary to reproduce the quark anti-quark string tension of the corresponding mesonic system at finite temperature.

hep-lat↗

arXiv2017

A novel nuclear dependence of nucleon-nucleon short-range correlations

A linear correlation is found between the magnitude of nucleon-nucleon short-range correlations and the nuclear binding energy per nucleon with pairing energy removed. By using this relation, the strengths of nucleon-nucleon short-range correlations of some unmeasured nuclei are predicted. Discussions on nucleon-nucleon pairing energy and nucleon-nucleon short-range correlations are made. The found nuclear dependence of nucleon-nucleon short-range correlations may shed some lights on the short-range structure of nucleus.

nucl-th↗

arXiv2017

Global study of nuclear modifications on parton distribution functions

A global analysis of nuclear medium modifications of parton distributions is presented using deeply inelastic scattering data of various nuclear targets. Two obtained data sets are provided for quark and gluon nuclear modification factors, referred as nIMParton16. One is from the global fit only to the experimental data of isospin-scalar nuclei (Set A), and the other is from the fit to all the measured nuclear data (Set B). The scale-dependence is described by DGLAP equations with nonlinear corrections in this work. The Fermi motion and off-shell effect, nucleon swelling, and parton-parton recombination are taken into account together for modeling the complicated $x$-dependence of nuclear modification. The nuclear gluon shadowing in this paper is dynamically generated by the QCD evolution of parton splitting and recombination processes with zero gluon density at the input scale. Sophisticated nuclear dependence of nuclear medium effects is studied with only two free parameters. With the obtained free parameters from the global analysis, the nuclear modifications of parton distribution functions of unmeasured nuclei can be predicted in our model. Nuclear modification of deuteron is also predicted and shown with recent measurement at JLab.

hep-ph↗

arXiv2017

Dynamical parton distributions from DGLAP equations with nonlinear corrections

Determination of proton parton distribution functions is present under the dynamical parton model assumption by applying DGLAP equations with GLR-MQ-ZRS corrections. We provide two data sets, referred as IMParton16, which are from two different nonperturbative inputs. One is the naive input of three valence quarks and the other is the input of three valence quarks with flavor-asymmetric sea components. Basically, both data sets are compatible with the experimental measurements at high scale ($Q^2>2$ GeV$^2$). Furthermore, our analysis shows that the input with flavor-asymmetric sea components better reproduce the structure functions at high $Q^2$. Generally, the obtained parton distribution functions, especially the gluon distribution function, are the good options of inputs for simulations of high energy scattering processes. The analysis is performed under the fixed-flavor number scheme for $n_f=$ 3, 4, 5. Both data sets start from very low scales around 0.07 GeV$^2$, where the nonperturbative input is directly connected to the simple picture of quark model. These results may shed some lights on the origin of the parton distributions observed at high $Q^2$.

hep-ph↗

arXiv2017

Faddeev fixed center approximation to $π\bar{K} K^*$ system and the $π_1(1600)$

We investigate the three-body system of $π\bar{K} K^*$ by using the fixed-center approximation to the Faddeev equation, taking the interaction between $π$ and $\bar{K}$, $π$ and $K^*$, and $\bar{K}$ and $K^*$ from the chiral unitary approach. The study is made assuming scattering of a $π$ on a $\bar{K} K^*$ cluster, which is known to generate the $f_1(1285)$ state. The resonant structure around $1650$ MeV shows up in the modulus squared of the $π$-$(\bar{K} K^*)_{f_1(1285)}$ scattering amplitude and suggests that a $π$-$(\bar{K} K^*)_{f_1(1285)}$ state, with "exotic" quantum numbers $J^{PC} = 1^{-+}$, can be formed. This state can be identified as the observed $π_1(1600)$ resonance. We suggest that this is the origin of the present $π_1(1600)$ resonance and propose to look at the $πf_1(1285)$ mode in future experiments to clarify the issue.

hep-ph↗

arXiv2016

Production of charmed baryon $Λ_c(2940)$ by kaon-induced reaction on a proton target

We investigate the possibility to study the charmed baryon $Λ_c(2940)$ by kaon-induced reaction on a proton target. By assuming the $Λ_c(2940)$ as a $pD^{*0}$ molecular state with spin-parity $J^{p}=1/2^{\pm}$, an effective Lagrangian approach was adopted to calculate the cross section, the $D^0p$ invariant mass spectrum and Dalitz plot of the $Λ(2940)$ production. The total cross section of the $K^{-}p\toΛ_c(2940)D_s^{-}$ reaction is found at an order of magnitude about 10 $μ$b. By considering the sub sequential decay $Λ_c(2940)\to{}D^0p$ with contributions from the $Λ_c(2286)$ and the $Σ_c(2455)$ as background, the $K^{-}p\to{}D_{s}^{-}D^{0}p$ reaction are studied. It is found that the $Λ_c(2940)$ is produced mainly at forward angles. The $Λ_c(2940)$ signal is predicted to be significant in the $D^0p$ invariant mass spectrum and the Dalitz plot of the $K^{-}p\to{}D_{s}^{-}D^{0}p$ reaction. The results suggest that it is promising to study the $Λ_c(2940)$ with high-energy kaon beam on a proton target in experiment.

hep-ph↗

arXiv2016

Partonic structure of proton in the resonance region

We separate the contributions of parton distributions from higher twist corrections to the deeply inelastic lepton-proton scattering in the resonance region using the Jefferson Lab data at low $Q^2$. The study indicates that the concept of the valence quarks and their distributions are indispensable even at $Q^2<1GeV^2$. The quark-hadron duality is also discussed.

hep-ph↗

arXiv2016

Photoproduction of hidden-charm states in the $γp \to \bar{D}^{*0} Λ^+_c$ reaction near threshold

We report on a theoretical study of the hidden charm $N^*_{c \bar{c}}$ states in the $γp \to \bar{D}^{*0} Λ^+_c$ reaction near threshold within an effective Lagrangian approach. In addition to the contributions from the $s$-channel nucleon pole, the $t$-channel $D^0$ exchange, the $u$-channel $Λ^+_c$ exchange and the contact term, we study the contributions from the $N^*_{c \bar{c}}$ states with spin-parity $J^P = 1/2^-$ and $3/2^-$. The total and differential cross sections of the $γp \to \bar{D}^{*0} Lambda^+_c$ reaction are predicted. It is found that the contributions of these $N^*_{c \bar{c}}$ states give clear peak structures in the total cross sections. Thus, this reaction is another new platform to study the hidden-charm states. It is expected that our model calculation may be tested by the future experiments.

nucl-th↗

arXiv2016

$\bar{K}$ -induced formation of the $f_2(1270)$ and $f_2^{'}(1525)$ resonances on proton targets

We investigate the productiong of $f_2(1270)$ and $f_2^{'}(1525)$ mesons in the $K^{-}p\toΛf_2(1270)$,$K^{-}p\toΛf^{'}_2(1525)$ and $K^{-}p\to{}K^{+}K^{-}Λ$ reactions within an effective Lagrangian approach. For $K^{-}p\to{}f_2Λ$ reaction, by considering the contributions from the $t$-channel $K^{+}$ exchange and $u$-channel nucleon pole, we get a fairly good description of the experimental measurements about the total and differential cross sections. Based on the studies of the $K^{-}p\to{}f_2Λ$ reaction, we investigate $K^{-}p\to{}K^{+}K^{-}Λ$ reaction including the contributions from the $f_2(1270)$ and $f'_2(1525)$ mesons decaying into $K^+K^-$ pair. The total cross sections and invariant mass distribution of the $K p \to K^+K^- Λ$ reaction are predicted. The results can be tested in future experiments and therefore offer new clues on the nature of these tensor states.

hep-ph↗

arXiv2016

Exclusive $J/ψ$ Production in Diffractive Process with AdS/QCD Holographic Wave Function in BLFQ

The AdS/QCD holographic wave function of basis light-front quantization (BLFQ) for vector meson $J/ψ$ is applied in this manuscript. The exclusive production of $J/ψ$ in diffractive process is computed in dipole model with AdS/QCD holographic wave function. We use IP-Sat and IIM model in the calculation of the differential cross section of the dipole scattering off the proton. The prediction of AdS/QCD holographic wave function in BLFQ gives a good agreement to the experimental data.

hep-ph↗

arXiv2016

The $ J/ψ$ production in PbPb ultraperipheral collisions at $\sqrt{s_{NN}}=2.76\mathrm{TeV}$

We calculate the coherent and incoherent production of $J/ψ$ in PbPb ultraperipheral collisions. The production of $J/ψ$ in ultraperipheral collsions is product of photon flux distributions and cross section of photon-nucleus scatterings. The distributions of photon flux is computed in light-cone perturbation theory and the cross section of photon-nucleus scatterings is calculated in dipole model, we assume that the two gluons exchange contribution is the coherent cross section and the large-$N_c$ contribution is the incoherent cross section in photon-nucleus scattering. The numerical result of the rapidity distributions of $J/ψ$ production in PbPb ultraperipheral collisions at $\sqrt{s_{NN}}=2.76$TeV are compared with the experimental data measured by the ALICE collaboration.

hep-ph↗

arXiv2016

The coherent cross section of vector mesons in ultraperipheral PbPb collisions at the LHC

The coherent cross section of $J/ψ$, $ρ$, $ϕ$ are computed in dipole model in the ultraperipheral PbPb collisions, the IP-Sat and IIM model are applied in the calculation of the differential cross section of the dipole scattering off the nucleon, three kinds of forward vector meson wave functions are used in the overlap. The prediction of $J/ψ$ and $ρ$ is compared with the experimental data of the ALICE Collaboration, and the prediction of $ϕ$ is also given in this paper.

hep-ph↗

arXiv2016

The $Ξ^* \bar{K}$ and $Ωη$ interaction within a chiral unitary approach

In this work we study the interaction of the coupled channels $Ωη$ and $Ξ^* \bar{K}$ within the chiral unitary approach. The systems under consideration have total isospins $0$, strangeness $S = -3$, and spin $3/2$. We studied the $s$ wave interaction which implies that the possible resonances generated in the system can have spin-parity $J^P = 3/2^-$. The unitary amplitudes in coupled channels develop poles that can be associated with some known baryonic resonances. We find there is a dynamically generated $3/2^-$ $Ω$ state with mass around $1800$ MeV, which is in agreement with the predictions of the five-quark model.

nucl-th↗

arXiv2015

A determination of the flavor asymmetric sea quarks in the proton

Using DGLAP evolution equation with the corrections of parton recombinations, the flavor asymmetric sea quark distributions in the proton are first extracted from the available experimental data with the global QCD analysis method. Comparisons of our predictions to the CTEQ, MRS, and GRV parton distribution functions for sea quarks are presented. Based on the separation of the flavor symmetric and asymmetric sea, the possible relations between strange quark distribution and symmetric light quark distribution are discussed. The results are used to explain the recent HERMES result of the strange quark distribution.

hep-ph↗

arXiv2015

IsoDAR Neutrino Experiment Simulation with Proton and Deuteron Beams

In this paper we consider high-intensity source of electron antineutrinos from the production and subsequent decay of 8Li. It opens a wide range of possible searches for beyond standard model physics via studies of the inverse beta decay interaction. In IsoDAR experiments Lithium 8 is a short lived beta emitter producing a high intensity anti-neutrinos, which is very suitable for making several important neutrino experiments. In this paper we used the GEANT4 program. to simulate neutrino production using proton and deuteron beams. We find that the neutrino production rate is about 3 times from deuteron beam than from proton beam in low energy region.

physics.ins-det↗

arXiv2015

Extend the Kompaneets Equation to Down-Comptonization Process in a Novel Way

Comptonization is a very important phenomenon in astrophysics. Kompaneets equation describes up-Comptonization process in nonrelativistic astrophysics, while it fails for down-Comptonization Scattering which is the most important radiative transfer process in hard X-rays and $γ$-rays astronomy. In this study, we explore both up-Comptonization and down-Comptonization processes. A new relativistic corrections is introduced to the Kompaneets equation which is valid in both nonrelativistic energy regime with the photon energy $hν<< m_ec^2$ and the electron temperature $KT_e << m_ec^2$. Numerical comparisons are presented which show excellent agreement between the Kompaneets equation and the new equation.

astro-ph.HE↗