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Bin Zhang

Publications and source records attributed to Bin Zhang.

At least 289 records · Page 16Linked to original sources
arXiv2011

Effects of final state interactions on charge separation in relativistic heavy ion collisions

Charge separation is an important consequence of the Chiral Magnetic Effect. Within the framework of a multi-phase transport model, the effects of final state interactions on initial charge separation are studied. We demonstrate that charge separation can be significantly reduced by the evolution of the Quark-Gluon Plasma produced in relativistic heavy ion collisions. Hadronization and resonance decay can also affect charge separation. Moreover, our results show that the Chiral Magnetic Effect leads to the modification of the relation between the charge azimuthal correlation and the elliptic flow that is expected from transverse momentum conservation only. The transverse momentum and pseudorapidity dependences of, and the effects of background on the charge azimuthal correlation are also discussed.

nucl-th↗
arXiv2011

Chemical and kinetic equilibrations via radiative parton transport

A hot and dense partonic system can be produced in the early stage of a relativistic heavy ion collision. How it equilibrates is important for the extraction of Quark-Gluon Plasma properties. We study the chemical and kinetic equilibrations of the Quark-Gluon Plasma using a radiative transport model. Thermal and Color-Glass-Condensate motivated initial conditions are used. We observe that screened parton interactions always lead to partial pressure isotropization. Different initial pressure anisotropies result in the same asymptotic evolution. Comparison of evolutions with and without radiative processes shows that chemical equilibration interacts with kinetic equilibration and radiative processes can contribute significantly to pressure isotropization.

nucl-th↗
arXiv2010

Spontaneous Symmetry Breaking during Formation of ZnO Nanocrystals

Systemic symmetry is introduced into our work to investigate the symmetries of different ZnO nanocrystals. Result shows that systemic symmetries obey the law of spontaneous symmetry breaking during the formation of ZnO nanocrystals. A unitary formation mechanism of ZnO nanocrystals is proposed accordingly. Our results provide new insight into both crystallization and spontaneous symmetry breaking at meso-scale.

cond-mat.mes-hall↗
arXiv2010

Sea Quark Flavor Asymmetry of Hadrons in Statistical Balance Model

We derive a Menta Carlo method to simulate kinetic equilibrium ensemble, and get the same sea-quark flavor asymmetry as the linear equations method in statistical model. In the recent paper, we introduce the spilt factors to indicate the quarks' or gluons' spilt $g\rightarrow q\bar{q}(gg)$ and $q\rightarrow qg$ ability. We obtain the almost fixed asymmetry value $0.12-0.16$ which consists with experimental measurements for proton, when the spilt factors vary in a very wide range over four orders of magnitude. So, we proof the sea quark asymmetry can be derived from statistic principle and not sensitively dependents on the dynamics details of quarks and gluons in proton. We also apply the Menta Carlo method of statistical model to predict the sea-quark asymmetry values for $K$ mesons, octet baryons $Σ$,$Ξ$ and $Δ$ baryons, even for exotic pentaquark states. All these asymmetry values just only dependent on the valence quarks numbers in those hadrons.

hep-ph↗
arXiv2010

Parton radiative processes and pressure isotropization in relativistic heavy ion collisions

The impact of radiative processes on kinetic equilibration is studied via a radiative transport model. The 2 <-> 3 processes can significantly increase the level of thermalization. These processes lead to an approximate coupling constant scaling of the evolution of the pressure anisotropy qualitatively different from the case with only 2 -> 2 partonic processes. Furthermore, thermal and Color Glass Condensate motivated initial conditions are shown to share the same asymptotic evolution when 2 <-> 3 processes are included. This emphasizes the unique role of radiative processes in Quark-Gluon Plasma thermalization.

nucl-th↗
arXiv2009

Thermalization through parton transport

A radiative transport model is used to study kinetic equilibration during the early stage of a relativistic heavy ion collision. The parton system is found to be able to overcome expansion and move toward thermalization via parton collisions. Scaling behaviors show up in both the pressure anisotropy and the energy density evolutions. In particular, the pressure anisotropy evolution shows an approximate alpha_s scaling when radiative processes are included. It approaches an asymptotic time evolution on a time scale of 1 to 2 fm/c. The energy density evolution shows an asymptotic time evolution that decreases slower than the ideal hydro evolution. These observations indicate that partial thermalization can be achieved and viscosity is important for the evolution during the early longitudinal expansion stage of a relativistic heavy ion collision.

nucl-th↗
arXiv2009

Double shuffle relations and renormalization of multiple zeta values

In this paper we present some of the recent progresses in multiple zeta values (MZVs). We review the double shuffle relations for convergent MZVs and summarize generalizations of the sum formula and the decomposition formula of Euler for MZVs. We then discuss how to apply methods borrowed from renormalization in quantum field theory and from pseudodifferential calculus to partially extend the double shuffle relations to divergent MZVs.

math.NT↗
arXiv2009

Discovery Potential of New Boson $W_1^{\pm}$ in the Minimal Higgsless Model at LHC

In this paper, we demonstrate the LHC discovery potential of new charged vector boson $W_1^{\pm}$ predicted by the Minimal Higgsless model in the process $pp\to W_1^{\pm}qq^{\prime}\to W^{\pm}Z^0qq^\prime\to \ell^{\pm}\ell^+\ell^-νqq^{\prime}(\ell=e,μ)$ by analyzing the generator level events of the signal and backgrounds. The generator for the signal $pp \to {W_1}^{\pm}qq^\prime\to W^{\pm}Z^0qq^\prime$ at tree level is developed with the Minimal Higgsless model and then interfaced with PYTHIA for the parton showers and hadronization. The backgrounds are produced with PYTHIA and ACERMC. We give integrated luminosities required to discover 5$σ$ signal as a function of $W_1^{\pm}$ mass.

hep-ex↗
arXiv2009

The Search for Heavy Majorana Neutrinos

The Majorana nature of neutrinos can be experimentally verified only via {\it lepton-number} violating processes involving charged leptons. We study 36 lepton-number violating ($\lv$) processes from the decays of tau leptons and pseudoscalar mesons. These decays are absent in the Standard Model but, in presence of Majorana neutrinos in the mass range $\sim 100 \mev$ to $5 \gev$, the rates for these processes would be enhanced due to their resonant contribution. We calculate the transition rates and branching fractions and compare them to the current bounds from direct experimental searches for $\dl=2$ tau and rare meson decays. The experimental non-observation of such $\lv$ processes places stringent bounds on the Majorana neutrino mass and mixing and we summarize the existing limits. We also extend the search to hadron collider experiments. We find that, at the Tevatron with $8 {fb}^{-1}$ integrated luminosity, there could be $2σ$ ($5σ$) sensitivity for resonant production of a Majorana neutrino in the $μ^\pm μ^\pm$ modes in the mass range of $\sim 10 - 180 {\gev} (10 - 120 {\gev})$. This reach can be extended to $\sim 10 - 375 {\gev} (10 - 250 mbox{\gev})$ at the LHC of 14 TeV with $100 {fb}^{-1}$. The production cross section at the LHC of 10 TeV is also presented for comparison. We study the $μ^\pm e^\pm$ modes as well and find that the signal could be large enough even taking into account the current bound from neutrinoless double-beta decay. The signal from the gauge boson fusion channel $W^+ W^+\to \ell^+_1 \ell^+_2$ at the LHC is found to be very weak given the rather small mixing parameters. We comment on the search strategy when a $τ$ lepton is involved in the final state.

hep-ph↗
arXiv2009

Anomalous gauge couplings of the Higgs boson at the CERN LHC: Semileptonic mode in WW scatterings

We make a full tree level study of the signatures of anomalous gauge couplings of the Higgs boson at the CERN LHC via the semileptonic decay mode in WW scatterings. Both signals and backgrounds are studied at the hadron level for the Higgs mass in the range 115 GeV to 200 GeV. We carefully impose suitable kinematical cuts for suppressing the backgrounds. To the same sensitivity as in the pure leptonic mode, our result shows that the semileptonic mode can reduce the required integrated luminosity by a factor of 3. If the anomalous couplings in nature are actually larger than the sensitivity bounds shown in the text, the experiment can start the test for an integrated luminosity of 50 inverse fb.

hep-ph↗
arXiv2009

Kinetic equilibration from a radiative transport

Kinetic equilibration during the early stage of a relativistic heavy ion collision is studied using a radiative transport model. Thermalization is found to dominate over expansion with medium regulated cross sections. Pressure anisotropy shows an approximate alpha_s scaling when radiative processes are included. It approaches an asymptotic time evolution on a time scale of 1 to 2 fm/c. Energy density is also found to approach an asymptotic time evolution that decreases slower than the ideal hydro evolution. These observations indicate that viscosity is important during the early longitudinal expansion phase of a relativistic heavy ion collision.

nucl-th↗
arXiv2008

A Stringy Product on Twisted Orbifold K-theory

In this paper we define an associative stringy product for the twisted orbifold K-theory of a compact, almost complex orbifold X. This product is defined on the twisted K-theory of the inertia orbifold of X, where the twisting gerbe is assumed to be in the image of the inverse transgression map.

math.AT↗
arXiv2008

Recent results from parton cascade and microscopic transport

Parton cascade is a microscopic transport approach for the study of the space-time evolution of the Quark-Gluon Plasma produced in relativistic heavy ion collisions and its experimental manifestations. In the following, parton cascade calculations on elliptic flow and thermalization will be discussed. Dynamical evolution is shown to be important for the production of elliptic flow including the scaling and the breaking of the scaling of elliptic flow. The degree of thermalization is estimated using both an elastic parton cascade and a radiative transport model. A longitudinal to transverse pressure ratio, $P_L/P_T\approx 0.8$, is shown to be expected in the central cell in central collisions. This provides information on viscous corrections to the ideal hydrodynamical approach.

nucl-th↗
arXiv2008

LHC Signatures of New Gauge Bosons in the Minimal Higgsless Model

We study the LHC signatures of new gauge bosons in the gauge-invariant minimal Higgsless model. It predicts an extra pair of W_1 and Z_1 bosons which can be as light as ~400GeV and play a key role in the delay of unitarity violation. We analyze the W_1 signals in pp --> W_0Z_0Z_0 --> jj4\ell and pp --> jj W_0Z_0 --> jj3\ellνprocesses at the LHC, including the complete electroweak and QCD backgrounds. We reveal the complementarity between these two channels for discovering the W_1 boson, and demonstrate the LHC discovery potential over the full range of allowed W_1 mass.

hep-ph↗
arXiv2008

Pressure isotropization of an equilibrating quark-gluon plasma

Pressure isotropization of an equilibrating quark-gluon plasma produced in relativistic heavy ion collisions is studied within the framework of a multi-phase transport model (AMPT). The time evolution of the bulk properties of the quark-gluon plasma is found to depend on its expansion dynamics and hadronization scheme as well as the scattering cross sections among quarks and gluons. It is further found that the pressure isotropy of the produced quark-gluon plasma can only be achieved temporarily, indicating that there is only partial thermalization during the time evolution of the quark-gluon plasma.

nucl-th↗
arXiv2007

Equation of state of the hot dense matter in a multi-phase transport model

Within the framework of a multi-phase transport model, we study the equation of state and pressure anisotropy of the hot dense matter produced in central relativistic heavy ion collisions. Both are found to depend on the hadronization scheme and scattering cross sections used in the model. Furthermore, only partial thermalization is achieved in the produced matter as a result of its fast expansion.

nucl-th↗
arXiv2006

Renormalization of multiple zeta values

Multiple zeta values (MZVs) in the usual sense are the special values of multiple variable zeta functions at positive integers. Their extensive studies are important in both mathematics and physics with broad connections and applications. In contrast, very little is known about the special values of multiple zeta functions at non-positive integers since the values are usually singular. We define and study multiple zeta functions at any integer values by adapting methods of renormalization from quantum field theory, and following the Hopf algebra approach of Connes and Kreimer. This definition of renormalized MZVs agrees with the convergent MZVs and extends the work of Ihara-Kaneko-Zagier on renormalization of MZVs with positive arguments. We further show that the important quasi-shuffle (stuffle) relation for usual MZVs remains true for the renormalized MZVs.

math.NT↗