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IOPP Seminar- Dr. YU Ning,,3:30pm，Oct.12,Monday

 Talk 1 Time:2:30pm, Oct.16, Monday Place:Room 9-409 Speaker: Chen Ji, Postdoctoral Researcher, ECT*-TIFPA, Trento, Italy Title: "Nuclear structure effects in exotic atoms" Abstract: The proton radius extracted from recent high-precision spectroscopy measurements in muonic hydrogen disagrees significantly with that determined from electronic hydrogen spectroscopy or electron-proton elastic scattering. Intrigued by the proton radius puzzle, new measurements of the Lamb shift in other light muonic atoms will be performed at PSI. These experiments aim to extract the nuclear charge radius with high accuracies, however limited by our knowledge of nuclear polarizability corrections. The nuclear polarizabilities are QCD effects that contribute to the atomic spectrum. They need to be provided by theory with high accuracy. I will talk about how we perform ab-initio calculations of such nuclear polarizability using state-of-the-art nuclear Hamiltonians, with a precision that satisfies the experimental requirement. I will present results for several light muonic atoms, and discuss the uncertainties from both atomic and nuclear physics. I will future extend the discussion to nuclear structure effects in electronic atoms containing light halo nuclei near the edge of stability. These nuclei are easier to be excited by the surrounding electrons. As an example, I will discuss the calculation of 6He with the halo effective field theory, and the possible extension to obtain the nuclear polarizability, which is important for extracting the radius of a halo nucleus from spectroscopic measurements. PPT DOWNLOAD http://ioppweb.ccnu.edu.cn/uploads/soft/151110/54_0919576071.pdf Talk 2 Time:3:30pm，Oct.12,Monday Location:Room9409 Speaker: Dr. YU Ning Title:Beam energy dependence of deuteron production in Au + Au collisions at RHIC The production of light nuclei with small binding energy such as (anti)deuterons, can be used to study the freeze-out properties and local baryon density in high-energy nuclear collisions. The azimuthal anisotropic results of protons and deuterons have shown that the coalescence is the dominant process for the light nuclei production at later stage of the evolution.\\ %\hspace{0.3cm}In this talk we present a systematic study of colliding energy, centrality, and transverse momentum dependence of mid-rapidity deuteron and anti-deuteron production, measured by the STAR experiment, from Au + Au collisions at RHIC at $\sqrt{s_{NN}}$ = 7.7, 11.5, 14.5, 19.6, 27, 39 and 200 GeV. Deuterons, protons and their anti-particles are identified using the time projection chamber (TPC) and time-of-flight detector (TOF). Proton and anti-proton yields are corrected from weak decays. The $B_2$ parameters, defined as $N(d)/N^2(p)$, which measure the phase space density for nucleons show a difference between $B_2(d)$) and $B_2(\bar{d})$. These observations may imply that baryon and anti-baryon freeze-out at different densities. PPT DOWNLOAD
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