Mon·Jul 6, 2009Monday·July 6, 2009

1. 01*

   Spectroscopy of 13B via the 13C(t,3He) reaction at 115 AMeV

   C. J. Guess🇺🇸 · R.G.T. Zegers🇺🇸 · B.A. Brown🇺🇸 · Sam M. Austin🇺🇸 · D. Bazin🇺🇸 · C. Caesar🇺🇸 · J.M. Deaven🇺🇸 · G.F. Grinyer🇺🇸 · C. Herlitzius🇺🇸 · G.W. Hitt🇺🇸 · S. Noji🇯🇵 · R. Meharchand🇺🇸 and 4 other authors

   Gamow-Teller and dipole transitions to final states in 13B were studied via the 13C(t,3He) reaction at Et = 115 AMeV. Besides the strong Gamow-Teller transition to the 13B ground state, a weaker Gamow-Teller transition to a state at 3.6 MeV was found. This state was assigned a spin-parity of 3/2- by comparison with shell-model calculations using the WBP and WBT interactions which were modified to allow for mixing between nhw and (n+2)hw configurations. This assignment agrees with a recent result from a lifetime measurement of excited states in 13B. The shell-model calculations also explained the relatively large spectroscopic strength measured for a low-lying 1/2+ state at 4.83 MeV in 13B. The cross sections for dipole transitions up to Ex(13B)= 20 MeV excited via the 13C(t,3He) reaction were also compared with the shell-model calculations. The theoretical cross sections exceeded the data by a factor of about 1.8, which might indicate that the dipole excitations are "quenched". Uncertainties in the reaction calculations complicate that interpretation.

   nucl-exPRC(2009)·19 citations
2. 02*

   Fragmentation of relativistic nuclei in peripheral interactions in nuclear track emulsion

   D.A. Artemenkov🇷🇺 · V. Bradnova🇷🇺 · M.M. Chernyavsky🇷🇺 · L.A. Goncharova🇷🇺 · M. Haiduc🇷🇴 · N.A. Kachalova🇷🇺 · S.P. Kharlamov🇷🇺 · A.D. Kovalenko🇷🇺 · A.I. Malakhov🇷🇺 · A.A. Moiseenko🇦🇲 · G.I. Orlova🇷🇺 · N.G. Peresadko🇷🇺 and 10 other authors

   The technique of nuclear track emulsions is used to explore the fragmentation of light relativistic nuclei down to the most peripheral interactions - nuclear "white" stars. A complete pattern of therelativistic dissociation of a ${}^8$B nucleus with target fragment accompaniment is presented. Relativistic dissociation ${}^9$Be$\to 2\alpha$ is explored using significant statistics and a relative contribution of ${}^8$Be decays from 0${}^{+}$ and 2${}^{+}$ states is established. Target fragment accompaniments are shown for relativistic fragmentation ${}^{14}$N$\to$3He+H and ${}^{22}$Ne$\to$5He. The leading role of the electromagnetic dissociation on heavy nuclei with respect to break-ups on target protons is demonstrated in all these cases. It is possible to conclude that the peripheral dissociation of relativistic nuclei in nuclear track emulsion is a unique tool to study many-body systems composed of lightest nuclei and nucleons in the energy scale relevant for nuclear astrophysics.

   nucl-exPhys.Atom.Nucl.(2008)·1 citation
3. 03*

   Heavy Ion Physics with ALICE

   Mercedes López Noriega (for the ALICE Collaboration)🇨🇭

   ALICE will study the physics of the strongly interacting matter produced in nucleus-nucleus collisions at the LHC where the formation of the Quark Gluon Plasma is expected. The experimental setup, the capabilities of the detector, and a few selected heavy-ion topics are presented and discussed.

   nucl-ex0 citations
4. 04*

   Comments on 'Piezonuclear decay of thorium' by F. Cardone et. al

   G. Ericsson🇸🇪 · S. Pomp🇸🇪 · H. Sjöstrand🇸🇪 · E. Traneus🇸🇪

   Subjecting a solution of 228Th to ultrasound (20 kHz, 100W), Cardone et al. [Phys. Lett. A 373 (2009) 1956] claim to observe an increase in the transformation or decay rate of 228Th by a factor of 104. The evidence provided seems however far from conclusive and in part contradictory to the claims made. In fact, looking at the presented data we find it cannot be taken as justification to discard the null hypothesis, namely, that the data from exposed and non exposed samples are drawn from the same distribution. We suggest a number of additional tests that should be made in order to improve the quality of the study and test the hypothesis of so-called piezonuclear reactions.

   nucl-exphysics.plasm-phPLA(2009)·1 citation
5. 05*

   The N* Physics Program at Jefferson Lab

   Volker D. Burkert🇺🇸

   Recent measurements of nucleon resonance transition form factors with CLAS at Jefferson Lab are discussed. The new data confirm the assertion of the symmetric constituent quark model of the Roper as the first radial excitation of the nucleon. For the first time, the longitudinal transition amplitude to the S11(1535) was extracted from the data. New results on the transition amplitudes for the D13(1520) resonance are presented showing a rapid transition from helicity 3/2 dominance seen at the real photon point to helicity 1/2 dominance at higher Q2. I also discuss aspects of the JLab program to search for new excited nucleon states predicted by quark models.

   nucl-exhep-exhep-lathep-ph+1CPC(2009)·6 citations
6. 06*

   Binding of D, D-bar and J/Psi mesons in nuclei

   K. Tsushima🇺🇸

   We estimate the $D$, $\overline{D}$ and $J/\Psi$ meson potentials in nuclei. $J/\Psi$-nuclear potential (self-energy) is calculated based on the color-singlet mechanism, by the $DD$ and $D{D}^{\ast }$ meson loops. This consistently includes the in-medium properties of $D$ and $D^{\ast }$ mesons. The potential obtained for the $J/\Psi$ meson is attractive, and it is complementary to the attraction obtained from the color-octet gluon-based mechanism. We predict that the $D^{-}$ and $J/\Psi$ mesons will be bound in nuclei under proper conditions.

   ↳ nucl-thhep-exhep-phnucl-exAIP Conf.Proc.(2009)·3 citations
7. 07*

   Summary of the J-PARC UCN Taskforce

   The J-Parc Ucn Taskforce: Tomokazu Aso🇯🇵 · Masatoshi Futakawa🇯🇵 · Tomiyoshi Haruyama🇯🇵 · Kazuo Hasegawa🇯🇵 · Yujiro Ikeda🇯🇵 · Masanori Ikegami🇯🇵 · Yukihide Kamiya🇯🇵 · Takashi Kato🇯🇵 · Nobuhiro Kimura🇯🇵 · Yoshiaki Kiyanagi🇯🇵 · Yasuo Maekawa🇯🇵 · Yasuhiro Masuda🇯🇵 and 10 other authors

   Discussions in the taskforce meetings in the period of Jan.-Mar. 2009 on the technical possibility of the ultracold neutron (UCN) source at the Japan Proton Accelerator Research Complex (J-PARC) is summarized.

   ↳ physics.ins-detnucl-ex3 citations
8. 08*

   A novel way to probe distribution amplitudes of neutral mesons in e^+e^- annihilation

   N.A. Kivel🇩🇪 · M.V. Polyakov🇩🇪

   We derive the amplitude for the process $e^{+}{e}^{-}\to {\pi }^0{\pi }^0$ at large invariant energy. The process goes through the two-photon exchange and its amplitude is expressed in terms of the convolution integral which depends on the shape of the pion distribution amplitude (DA) and the centre of mass scattering angle. Remarkable feature of the integral is that it is very sensitive to the end-point behaviour of the pion DA -- it starts to diverge if pion DA nullifies at the end-point as $\sqrt{x}$ or slower. That makes the $e^{+}{e}^{-}\to {\pi }^0{\pi }^0$ process unique probe of the shape of the meson DAs. The estimated cross section is rather small, for $\sqrt{s}=3$ GeV it ranges from a fraction of femtobarn (for the asymptotic DA) to couple of femtobarn (for the Chernyak-Zhitnitsky DA). The observation of the process $e^{+}{e}^{-}\to {\pi }^0{\pi }^0$ with the cross section higher as estimated here would imply very unusual form of the pion DA, e.g. the flat one. The derived amplitude can be easily generalized to other processes like $e^{+}{e}^{-}\to \sigma \sigma ,K_S{K}_S,\eta \eta ,{\eta }^{\prime }\eta ,{\pi }^0{f}_2$, etc.

   ↳ hep-phhep-exnucl-exJHEP(2009)·1 citation
9. 09*

   Electron-muon correlation as a new probe to strongly interacting quark-gluon plasma

   Yukinao Akamatsu🇯🇵 · Tetsuo Hatsuda🇯🇵 · Tetsufumi Hirano🇯🇵

   As a new and clean probe to the strongly interacting quark-gluon plasma (sQGP), we propose an azimuthal correlation of an electron and a muon which originate from the semileptonic decay of charm and bottom quarks. By solving the Langevin equation for the heavy quarks under the hydrodynamic evolution of the hot plasma, we show that substantial quenching of the away-side peak in the electron-muon correlation can be seen if the sQGP drag force acting on heavy quarks is large enough as suggested from the gauge/gravity correspondence. The effect could be detected in high-energy heavy-ion collisions at the Relativistic Heavy Ion Collider and the Large Hadron Collider.

   ↳ hep-phnucl-exnucl-thPRC(2009)·5 citations
10. 10*

    pi+Xi- Correlations and the ${\Xi }^{\ast }(1530)$ Puzzle

    B. O. Kerbikov🇷🇺 · R. Lednicky🇷🇺 · L. V. Malinina🇷🇺 · P. Chaloupka🇨🇿 · M. Šumbera🇨🇿

    The analysis of the preliminary RHIC data on ${\pi }^{+}-{\Xi }^{-}$ correlation function is carried out.The ${\Xi }^{\ast }(1530)$ resonance is successfully described. The values of the fireball radius and of the ${\pi }^{+}-{\Xi }^{-}$ scattering lengths are obtained.

    ↳ nucl-thhep-phnucl-ex1 citation
11. 11*

    Constraint fitting of experimental data with a jet quenching model embedded in a hydrodynamical bulk medium

    Nestor Armesto🇪🇸 · Matteo Cacciari🇫🇷 · Tetsufumi Hirano🇯🇵 · James L. Nagle🇺🇸 · Carlos A. Salgado🇪🇸

    We present a global fit to single- and double-inclusive suppression data of high-$p_T$ particles in central Au+Au collisions at top RHIC energy. We also include in this analysis data on heavy quarks via their D and B meson semi-leptonic decays (i.e. non-photonic electrons). The analysis is based on the parton quenching weights for medium-induced gluon radiation computed in the BDMPS approximation then embedded in a hydrodynamical description of the bulk medium. Our results indicate that values of the transport coefficient $\hat{q}$ more than four times larger than perturbative estimates are preferred by experimental data. This confirms previous calculations based on simpler implementations of the medium geometry or only the single-inclusive suppression. We also comment on the statistical compatibility of the heavy quark data within a radiative only energy loss scenario, and on the sensitivity of the results to nuclear modification of the parton distribution functions (PDFs) and to assumptions on the energy loss during times in the collision prior to the hydrodynamical behavior.}

    ↳ hep-phnucl-exnucl-thJ.Phys.G(2010)·83 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.