Thu·Dec 11, 2014Thursday·December 11, 2014

1. 01*

   Quantum Monte Carlo methods for nuclear physics

   J. Carlson🇺🇸 · S. Gandolfi🇺🇸 · F. Pederiva🇮🇹 · Steven C. Pieper🇺🇸 · R. Schiavilla🇺🇸 · K.E. Schmidt🇺🇸 · R.B. Wiringa🇺🇸

   Quantum Monte Carlo methods have proved very valuable to study the structure and reactions of light nuclei and nucleonic matter starting from realistic nuclear interactions and currents. These ab-initio calculations reproduce many low-lying states, moments and transitions in light nuclei, and simultaneously predict many properties of light nuclei and neutron matter over a rather wide range of energy and momenta. We review the nuclear interactions and currents, and describe the continuum Quantum Monte Carlo methods used in nuclear physics. These methods are similar to those used in condensed matter and electronic structure but naturally include spin-isospin, tensor, spin-orbit, and three-body interactions. We present a variety of results including the low-lying spectra of light nuclei, nuclear form factors, and transition matrix elements. We also describe low-energy scattering techniques, studies of the electroweak response of nuclei relevant in electron and neutrino scattering, and the properties of dense nucleonic matter as found in neutron stars. A coherent picture of nuclear structure and dynamics emerges based upon rather simple but realistic interactions and currents.

   ↳ nucl-thastro-ph.SRcond-mat.quant-gasnucl-ex+1RMP(2015)·850 citations
2. 02*

   Signatures of collective behavior in small systems

   Igor Kozlov🇨🇦 · Matthew Luzum🇨🇦 · Gabriel Denicol🇨🇦 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦

   We perform 3+1D viscous hydrodynamics calculations of proton-nucleus (pA) and nucleus-nucleus (AA) collisions. Our goal is to understand the apparent collective behavior recently observed in pA collisions and to verify whether the highest multiplicity collision systems can be accurately described as a relativistic fluid. We compare our calculations of flow variables to existing measurements, and demonstrate that hydrodynamics correctly captures the measured trends. We show that our predictions for the pair correlation observable $r_n$ are validated by recent experimental pA measurements, and that our results are sensitive to the granularity of the initial state. We also compare our results with measurements done for nucleus-nucleus collisions.

   ↳ nucl-thnucl-exNPA(2014)·15 citations
3. 03*

   Photoproduction of the $f_2(1270)$ resonance

   Ju-Jun Xie🇨🇳 · E. Oset🇪🇸

   We have performed a calculation of the $\gamma p\to {\pi }^{+}{\pi }^{-}p$ reaction, where the two pions have been separated in $D$-wave producing the $f_2(1270)$ resonance. We use elements of the local hidden gauge approach that provides the interaction of vector mesons in which the $f_2(1270)$ resonance appears as a $\rho$-$\rho$ molecular state in $L=0$ and spin 2. The vector meson dominance, incorporated in the local hidden gauge approach converts a photon into a ${\rho }^0$ meson and the other meson connects the photon with the proton. The picture is simple and has no free parameters, since the parameters of the theory have been constrained in the previous study of the vector-vector states. In a second step we introduce new elements, not present in the local hidden gauge approach, adapting the $\rho$ propagator to Regge phenomenology and introducing the $\rho NN$ tensor coupling. We find that both the differential cross section as well as the $t$ dependence of the cross section are in good agreement with the experimental results and provide support for the molecular picture of the $f_2(1270)$ in the first baryonic reaction where it has been tested.

   ↳ nucl-thhep-exhep-phnucl-exEPJA(2015)·18 citations
4. 04*

   Muonic atoms at RHIC

   Kefeng Xin (for the STAR Collaboration)🇺🇸

   We report the search results of muonic atoms from the STAR experiment at RHIC. The invariant mass distributions of hadron-muon pairs show peaks at the expected atom masses. Two particle correlation functions indicate the hadrons and muons that are close in phase space are emitted at the same space time point, which is a possible signature of muonic atom ionization at the beam pipe. The pion-muon correlation functions are further decomposed into two contributions, and the fraction of direct muons is obtained.

   ↳ hep-exnucl-ex2015 Journal of Physics: Conference Serie…·0 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.