Tue·Dec 2, 2014Tuesday·December 2, 2014

1. 01*

   Momentum sharing in imbalanced Fermi systems

   O. Hen · M. Sargsian · L.B. Weinstein · E. Piasetzky · H. Hakobyan · D. W. Higinbotham · M. Braverman · W.K. Brooks · S. Gilad · K. P. Adhikari · J. Arrington · G. Asryan and 129 other authors

   The atomic nucleus is composed of two different kinds of fermions, protons and neutrons. If the protons and neutrons did not interact, the Pauli exclusion principle would force the majority fermions (usually neutrons) to have a higher average momentum. Our high-energy electron scattering measurements using 12C, 27Al, 56Fe and 208Pb targets show that, even in heavy neutron-rich nuclei, short-range interactions between the fermions form correlated high-momentum neutron-proton pairs. Thus, in neutron-rich nuclei, protons have a greater probability than neutrons to have momentum greater than the Fermi momentum. This finding has implications ranging from nuclear few body systems to neutron stars and may also be observable experimentally in two-spin state, ultra-cold atomic gas systems.

   nucl-excond-mat.quant-gasnucl-thScience(2014)·333 citations
2. 02*

   Status of some P-wave baryon resonances and importance of inelastic channels

   Volker D. Burkert🇺🇸 · Hiroyuki Kamano🇯🇵 · Eberhard Klempt🇩🇪 · Deborah Ronchen🇩🇪 · Andrey V. Sarantsev🇩🇪 · Toru Sato🇯🇵 · Alfred Svarc🇭🇷 · Lothar Tiator🇩🇪 · Ron L. Workman🇺🇸

   We analyze the current status of three P-wave baryon states $N(1710){1/2}^{+}$, $N(1900){3/2}^{+}$, and $\Delta (1600){3/2}^{+}$ as given in the Review of Particles Physics (RPP). Since the evidence for a particle's existence is linked to its RPP "star" rating, we discuss its subjective present definition. We also present the accumulating evidence supporting these states and give our new "star" rating recommendations.

   nucl-exnucl-th9 citations
3. 03*

   Measurements of $ep\to e^{\prime }{\pi }^{+}n$ at W = 1.6 - 2.0 GeV and extraction of nucleon resonance electrocouplings at CLAS

   K. Park · I.G. Aznauryan · V.D. Burkert · the CLAS collaboration

   Differential cross sections of the exclusive process $ep\to e^{\prime }{\pi }^{+}n$ were measured with good precision in the range of the photon virtuality $Q^2=1.8-4.5$ GeV${}^2$, and the invariant mass range of the ${\pi }^{+}n$ final state W = 1.6 - 2.0 GeV using the CEBAF Large Acceptance Spectrometer. Data were collected with nearly complete coverage in the azimuthal and polar angles of the $n{\pi }^{+}$ center-of-mass system. More than 37,000 cross section points were measured. The contributions of the isospin $I=\frac{1}{2}$ resonances $N(1675){\frac{5}{2}}^{-}$, $N(1680){\frac{5}{2}}^{+}$ and $N(1710){\frac{1}{2}}^{+}$ were extracted at different values of $Q^2$ using a single-channel, energy-dependent resonance amplitude analysis. Two different approaches, the unitary isobar model and the fixed-$t$ dispersion relations, were employed in the analysis. We observe significant strength of the $N(1675){\frac{5}{2}}^{-}$ in the $A_{1/2}$ amplitude, which is in strong disagreement with quark models that predict both transverse amplitudes to be strongly suppressed. For the $N(1680){\frac{5}{2}}^{+}$ we observe a slow changeover from the dominance of the $A_{3/2}$ amplitude at the real photon point ($Q^2=0$) to a $Q^2$ where $A_{1/2}$ begins to dominate. The scalar amplitude $S_{1/2}$ drops rapidly with $Q^2$ consistent with quark model prediction. For the $N(1710){\frac{1}{2}}^{+}$ resonance our analysis shows significant strength for the $A_{1/2}$ amplitude at $Q^2<2.5$ GeV${}^2$.

   nucl-exPRC(2015)·67 citations
4. 04*

   Chemical freeze-out parameters in Beam Energy Scan Program of STAR at RHIC

   Sabita Das (for the STAR collaboration)🇮🇳

   The STAR experiment at RHIC has completed its first phase of the Beam Energy Scan (BES-I) program to understand the phase structure of the quantum chromodynamics (QCD). The bulk properties of the system formed in Au+Au collisions at different center of mass energy $\sqrt{s_{NN}}=$ 7.7, 11.5, 19.6, 27, and 39 GeV have been studied from the data collected in the year 2010 and 2011. The centrality and energy dependence of mid-rapidity ($|y|$ < 0.1) particle yields, and ratios are presented here. The chemical freeze-out parameters are extracted using measured particle ratios within the framework of a statistical model.

   nucl-exhep-exhep-phEPJ Web Conf.(2015)·17 citations
5. 05*

   Activation cross sections of $\alpha$-particle induced nuclear reactions on hafnium and deuteron induced nuclear reaction on tantalum: production of ${}^{178}$W/${}^{178m}$Ta generator

   F. Tárk'anyi · S. Tak'acs🇭🇺 · F. Ditrói🇭🇺 · A.Hermanne🇧🇪 · A.V. Ignatyuk · M.S. Uddin

   In the frame of a systematic study of charged particle production routes of medically relevant radionuclei, the excitation function for indirect production of ${}^{178m}$Ta through ${}^{nat}$Hf($\alpha$,xn)${}^{178}$W-${}^{178m}$Ta nuclear reaction was measured for the first time up to 40 MeV. In parallel, the side reactions ${}^{nat}$Hf($\alpha$,x)${}^{179,177,176,175}$W, ${}^{183,182,178g,177,176,175}$Ta, ${}^{179m,177m,175}$Hf were also assessed. Stacked foil irradiation technique and $\gamma$-ray spectrometry were used. New experimental cross section data for the ${}^{nat}$Ta(d,xn)${}^{178}$W reaction are also reported up to 40 MeV. The measured excitation functions are compared with the results of the ALICE-IPPE, and EMPIRE nuclear reaction model codes and with the TALYS 1.4 based data in the TENDL-2013 library. The thick target yields were deduced and compared with yields of other charged particle ((p,4n), (d,5n) and (${}^3$He,x)) production routes for ${}^{178}$W.

   nucl-exAppl.Radiat.Isot.(2014)·5 citations
6. 06*

   Identified particle production and freeze-out properties in heavy-ion collisions at RHIC Beam Energy Scan program

   Sabita Das (for the STAR collaboration)🇮🇳

   The first phase of Beam Energy Scan (BES) program at the Relativistic Heavy-Ion Collider (RHIC) was started in the year 2010 with the aim to study the several aspects of the quantum chromodynamics (QCD) phase diagram. The Solenoidal Tracker At RHIC (STAR) detector has taken data at $\sqrt{s_{NN}}=$ 7.7, 11.5, 19.6, 27, and 39 GeV in Au+Au collisions in the years 2010 and 2011 as part of the BES programme. For these beam energies, we present the results on the particle yields, average transverse mass and particle ratios for identified particles in mid-rapidity ($|y|$ < 0.1). The measured particle ratios have been used to study the chemical freeze-out dynamics within the framework of a statistical model.

   nucl-exhep-exhep-phEPJ Web Conf.(2015)·39 citations
7. 07*

   Assembly and bench testing of a spiral fiber tracker for the J-PARC TREK/E36 experiment

   Makoto Tabata🇯🇵 · Sébastien Bianchin🇨🇦 · Michael D. Hasinoff🇨🇦 · Robert S. Henderson🇨🇦 · Keito Horie🇯🇵 · Youichi Igarashi🇯🇵 · Jun Imazato🇯🇵 · Hiroshi Ito🇯🇵 · Alexander Ivashkin🇷🇺 · Hideyuki Kawai🇯🇵 · Yury Kudenko🇷🇺 · Oleg Mineev🇷🇺 and 3 other authors

   This study presents the recent progress made in developing a spiral fiber tracker (SFT) for use in the experiment TREK/E36 planned at the Japan Proton Accelerator Research Complex. This kaon decay experiment uses a stopped positive kaon beam to search for physics beyond the Standard Model through precision measurements of lepton universality and through searches for a heavy sterile neutrino and a dark photon. Detecting and tracking positrons and positive muons from kaon decays are of importance in achieving high-precision measurements; therefore, we designed and are developing the new tracking detector using a scintillating fiber. The SFT was completely assembled, and in a bench test, no dead channel was determined.

   ↳ physics.ins-dethep-exnucl-exJPS Conf.Proc.(2015)·5 citations
8. 08*

   Pion-assisted $N\Delta$ and $\Delta \Delta$ dibaryons, and beyond

   Avraham Gal🇮🇱

   Experimental evidence for $I(J^P)=0(3^{+})$ $\Delta \Delta$ dibaryon ${\mathcal{D}}_{03}(2370)$ has been presented recently by the WASA-at-COSY Collaboration. Here I review new hadronic-basis Faddeev calculations of $L=0$ nonstrange pion-assisted $N\Delta$ and $\Delta \Delta$ dibaryon candidates. These calculations are so far the only ones to reproduce the relatively small ${\mathcal{D}}_{03}(2370)$ width of 70--80 MeV. Predictions are also given for the location and width of ${\mathcal{D}}_{30}$, the $I(J^P)=3(0^{+})$ exotic partner of ${\mathcal{D}}_{03}(2370)$. Extensions to strangeness $\mathcal{S}=-1$ dibaryons are briefly discussed.

   ↳ nucl-thhep-phnucl-exHyperfine Interact.(2015)·5 citations
9. 09*

   Impact of the phonon coupling on the photon strength function

   Oleg Achakovskiy · Alexander Avdeenkov · Stephane Goriely🇧🇪 · Sergei Kamerdzhiev🇷🇺 · Siegfried Krewald🇩🇪

   The pygmy dipole resonances and photon strength functions in stable and unstable Ni and Sn isotopes are calculated within the microscopic self-consistent version of the extended theory of finite fermi systems which includes phonon coupling effects.The Skyrme forces SLy4 is used. A pygmy dipole resonance in ${}^{72}$Ni is predicted at the mean energy of 12.4 MeV exhausting 25.7\% of the total energy-weighted sum rule. The microscopically obtained photon E1 strength functions are compared with available experimental data and used to calculate nuclear reaction properties. Average radiative widths and radiative neutron capture cross sections have been calculated taking the phonon coupling into account as well as the uncertainties caused by various microscopic level density models. In all three quantities considered, the contribution of phonon coupling turned out to be significant and is found necessary to explain available experimental data.

   ↳ nucl-thnucl-exPRC(2015)·25 citations
10. 10*

    The chiral magnetic effect in heavy-ion collisions from event-by-event anomalous hydrodynamics

    Yuji Hirono🇺🇸 · Tetsufumi Hirano🇯🇵 · Dmitri E. Kharzeev🇺🇸

    The (3+1)D relativistic hydrodynamics with chiral anomaly is used to obtain a quantitative description of the chiral magnetic effect (CME) in heavy-ion collisions. We find that the charge-dependent hadron azimuthal correlations are sensitive to the CME, and that the experimental observations are consistent with the presence of the effect.

    ↳ hep-phnucl-exnucl-th83 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.