118882297
1D Longitudinal Beam Dynamics of Laser Plasma Wakefield Accelerator
In this paper, we get the 1D approximate analytical solution of the plasma electrostatic wake driven by the laser, and get the oscillating frequency of the wake modified by the nonlinear high order terms, and find that the frequency depends on the oscillating amplitudes of the wake and the laser which is the general nonlinear phenomenon. Finally we analyze the longitudinal beam dynamics in this electrostatic wake, and find that the high order terms don't change the topology of the longitudinal phase space.
119109800
Study on the production of the subpicosecond electron bunch
The production of the high brightness femtosecond electron bunch is now one of the hot research topics. This paper describes one electron linac facility used to produce the subpicosecond electron bunch. We analyze the main structure parameters, and study the beam dynamics of the facility. Finally, we discuss the application of this facility in Compton scattering.
56119429
Centrality dependence of particle production in p-Pb collisions at $\sqrt{s_{\rm NN} }$= 5.02 TeV
We report measurements of the primary charged-particle pseudorapidity density and transverse momentum distributions in p-Pb collisions at sNN=5.02TeV and investigate their correlation with experimental observables sensitive to the centrality of the collision. Centrality classes are defined by using different event-activity estimators, i.e., charged-particle multiplicities measured in three different pseudorapidity regions as well as the energy measured at beam rapidity (zero degree). The procedures to determine the centrality, quantified by the number of participants (Npart) or the number of nucleon-nucleon binary collisions (Ncoll) are described. We show that, in contrast to Pb-Pb collisions, in p-Pb collisions large multiplicity fluctuations together with the small range of participants available generate a dynamical bias in centrality classes based on particle multiplicity. We propose to use the zero-degree energy, which we expect not to introduce a dynamical bias, as an alternative event-centrality estimator. Based on zero-degree energy-centrality classes, the Npart dependence of particle production is studied. Under the assumption that the multiplicity measured in the Pb-going rapidity region scales with the number of Pb participants, an approximate independence of the multiplicity per participating nucleon measured at mid-rapidity of the number of participating nucleons is observed. Furthermore, at high-pT the p-Pb spectra are found to be consistent with the pp spectra scaled by Ncoll for all centrality classes. Our results represent valuable input for the study of the event-activity dependence of hard probes in p-Pb collisions and, hence, help to establish baselines for the interpretation of the Pb-Pb data.
119431648
Recent results on strangeness production at STAR
We report on the measurements of strange hadrons (K±, K0S, Λ, Ξ, Ω and ) production at mid-rapidity in Au+Au collisions at = 7.7 - 39 GeV from the STAR beam energy scan (BES) program. The collision energy dependence of strange hadron yields are presented. The strange hadron related particle ratios are compared with calculations from statistical and hadronic cascade models. The nuclear modification factors and baryon to meson ratios (/K0S and Ω/) are presented. The physics implications for collision dynamics are discussed.
35833011
Effect of partonic "wind" on charm quark correlations in high-energy nuclear collisions.
In high-energy collisions, massive heavy quarks are produced back to back initially and they are sensitive to early dynamical conditions. The strong collective partonic wind from the fast expanding quark-gluon plasma created in high-energy nuclear collisions modifies the correlation pattern significantly. While the hot and dense medium in collisions at the BNL Relativistic Heavy Ion Collider (sqrt[_s{NN}]=200 GeV) can only smear the initial back-to-back D_D correlation, a clear and strong near side D_D correlation is expected at the CERN Large Hadron Collider (sqrt[_s{NN}]=5500 GeV). This is considered as a signature for the strongly coupled quark-gluon plasma.
119304211
Hybrid model approach for strange and multistrange hadrons in 2.76A TeV Pb+Pb collisions
Using the VISHNU hybrid model, we calculate the multiplicity, spectra, and elliptic flow of $\Lambda$, $\Xi$ and $\Omega$ in 2.76 A TeV Pb+Pb collisions. Comparisons between our calculations and the ALICE measurements show that the model generally describes the soft hadron data of these strange and multi-strange hadrons at several centrality bins. Mass ordering of elliptic flow among $\pi$, K, p, $\Lambda$, $\Xi$ and $\Omega$ has also been studied and discussed. With a nice description of the particle yields, we explore chemical and thermal freeze-out of various hadrons species at the LHC within the framework of the VISHNU hybrid model.
116897708
Measurements of $K^0_s$, $\Lambda$ and $\Xi$ from Au+Au collisions at \sqrt{s_NN} = 7.7, 11.5 and 39 GeV in STAR
We report on the measurements of Ks, Lambda and Xi spectra at mid-rapidity (|y|<0.5) in the most central (0-5%) Au+Au collisions at \sqrt{s_NN} = 7.7, 11.5 and 39 GeV from the STAR experiment. The extracted yields and the corresponding data from Pb+Pb collisions measured by the NA49 and CERES experiments at SPS are consistent. The Lambda, Anti-Lambda, Xi- and Xi+ to pion ratios agree well with the predictions from a statistical hadronization model at all three energies.