Tue·Sep 22, 2015Tuesday·September 22, 2015

1. 01*

   Observation of neutron emission in the process of X-pinch

   O.D. Dalkarov · A.S. Rusetskii · S.A. Pikuz · T.A. Shelkovenko · I.N. Tilikin

   The results of measuring the neutron flux in the process of the X-pinch are presented. The measurements were carried out using CR-39 track detectors. It was found that in the process of X-pinch recorded neutron emission over a wide energy range (from thermal to energies greater than 10 MeV) with an intensity of more than 108 neutrons per shot into 4{\pi} sr solid angle (assuming isotropy of radiation and localizing the source in the "hot spot"). Data of track detectors suggest that at the time of discharge produced fast neutrons are then slowed down and turned into thermal.

   nucl-exphysics.ins-det0 citations
2. 02*

   Experimental aspects of quarkonia production and suppression in cold and hot nuclear matter

   A. D. Frawley🇺🇸

   When heavy Quarkonia are formed in collisions between between nuclei, their production cross section is modified relative to that in p+p collisions. The physical effects that cause this modification fall into two categories. Hot matter effects are due to the large energy density generated in the nuclear collision, which disrupts the formation of the quarkonium state. Cold nuclear matter effects are due to the fact that the quarkonium state is created in a nuclear target. I will review experimental aspects of quarkonia production due to both hot and cold matter effects.

   nucl-ex0 citations
3. 03*

   Recent results on two-particle correlations in ALICE

   Alice Ohlson (for the ALICE Collaboration)🇨🇭

   The discovery of correlations between particles separated by several units of pseudorapidity in high-multiplicity pp and p-Pb collisions, reminiscent of structures observed in Pb-Pb collisions, was a challenge to traditional ideas about collectivity in heavy ion collisions. In order to further explore long-range correlations and provide information to theoretical models, correlations between forward trigger muons and mid-rapidity associated hadrons were measured in p-Pb collisions at $\sqrt{s_{\text{mbox}NN}}=5.02\text{mbox}TeV$. The results demonstrate that the nearside and awayside ridges extend to $\Delta \eta \sim \pm 5$ and that the $v_2$ of muons, obtained from subtracting the correlation functions in high- and low-multiplicity events, is $(16\pm 6)\%$ higher in the Pb-going than in the p-going direction. The results are compared with AMPT simulations.

   nucl-exhep-exJ.Phys.Conf.Ser.(2016)·2 citations
4. 04*

   Examination of uncertainties in nuclear data for cosmic ray physics with the AMS experiment

   Nicola Tomassetti🇫🇷

   High-energy Li-Be-B nuclei in cosmic rays are being measured with unprecedent accuracy by the AMS experiment. These data bring valuable information to the cosmic ray propagation physics. In particular, combined measurements of B/C and Be/B ratios may allow to break the parameter degeneracy between the cosmic-ray diffusion coefficient and the size of the propagation region, which is crucial for dark matter searches. The parameter determination relies in the calculation of the Be and B production from collisions of heavier nuclei with the gas. Using the available cross-section data, I present for the first time an evaluation of the nuclear uncertainties and their impact in constraining the propagation models. I found that the AMS experiment can provide tight constraints on the transport parameters allowing to resolutely break the degeneracy, while nuclear uncertainties in the models are found to be a major limiting factor. Once these uncertainties are accounted, the degeneracy remains poorly resolved. In particular, the Be/B ratio at ~1 - 10 GeV/n is found not to bring valuable information for the parameter extraction. On the other hand, precise Be/B data at higher energy may be useful to test the nuclear physics inputs of the models.

   ↳ astro-ph.HEhep-phnucl-exPRC(2015)·31 citations
5. 05*

   Exact solutions of the Boltzmann equation and optimized hydrodynamic approaches for relativistic heavy-ion collisions

   U. Heinz (Ohio State)🇺🇸 · D. Bazow (Ohio State)🇺🇸 · G.S. Denicol (McGill)🇨🇦 · M. Martinez (Ohio State)🇺🇸 · M. Nopoush (Kent State)🇺🇸 · J. Noronha (U. Sao Paulo)🇧🇷 · R. Ryblewski (Krakow)🇵🇱 · M. Strickland (Kent State)🇺🇸

   Several recent results are reported from work aiming to improve the quantitative precision of relativistic viscous fluid dynamics for relativistic heavy-ion collisions. The dense matter created in such collisions expands in a highly anisotropic manner. Due to viscous effects this also renders the local momentum distribution anisotropic. Optimized hydrodynamic approaches account for these anisotropies already at leading order in a gradient expansion. Recently discovered exact solutions of the relativistic Boltzmann equation in anisotropically expanding systems provide a powerful testbed for such improved hydrodynamic approximations. We present the latest status of our quest for a formulation of relativistic viscous fluid dynamics that is optimized for applications to relativistic heavy-ion collisions.

   ↳ nucl-thhep-phnucl-exNucl.Part.Phys.Proc.(2016)·26 citations
6. 06*

   Surface Delta Interaction and g factors

   Xiaofei Yu · Larry Zamick🇺🇸

   Using an attractive surface delta interaction we obtain wave functions for 2 neutrons (or neutron holes) in the model space of 2 orbits (l=4, j=7/2) and (l=2, j=5/2). If we take the single particle energies to be degenerate we find that the g factors for I=2, 4 and 6 are all the same -namely the orbital g factor of the single nucleon. For a free neutron this quantity zero all 2particle or 2 hole g factors are equal to zero as well.. Only the orbital part of the g -factors contribute - the spin part cancels out. We then consider the effects of introducing a single energy splititng between the 2 orbits. We speculate that g factors for all n can be obtained by a linear approximation.

   ↳ nucl-thnucl-exNPA(2016)·1 citation
7. 07*

   Enhancement factor for two-neutron transfer reactions with a schematic coupled-channels model

   K. Hagino🇯🇵 · G. Scamps🇫🇷

   Probabilities for two-neutron transfer reactions, $P_{2n}$, are often discussed in comparison with the square of the corresponding probabilities for one-neutron transfer process, $(P_{1n}{)}^2$, implicitly assuming that $(P_{1n}{)}^2$ provides the probability of two-neutron transfer reactions in the absence of the pairing correlation. We use a schematic coupled-channels model, in which the transfers are treated as effective inelastic channels, and demonstrate that this model leads to $P_{2n}=(P_{1n}{)}^2/4$, rather than $P_{2n}=(P_{1n}{)}^2$, in the pure sequential limit. We argue that a simple model with spin-up and spin-down neutrons in a single-particle orbital also leads to the same conclusion.

   ↳ nucl-thnucl-exPRC(2015)·8 citations
8. 08*

   Factorization of event-plane correlations over transverse momentum in relativistic heavy ion collisions in a multi-phase transport model

   Kai Xiao · Feng Liu · Fuqiang Wang

   Momentum-space azimuthal harmonic event planes (EP) are constructed from final-state midrapidity particles binned in transverse momentum (pT ) in sqrt(s_NN) = 200 GeV Au+Au collisions in a multi-phase transport (AMPT) model. The EP correlations between pT bins, corrected by EP resolutions, are smaller than unity. This indicates that the EP's decorrelate over pT in AMPT, qualitatively consistent with data and hydrodynamic calculations. It is further found that the EP correlations approximately factorize into single pT-bin EP correlations to a common plane. This common plane appears to be the momentum-space EP integrated over all pT, not the configuration space participant plane (PP).

   ↳ nucl-thnucl-exPRC(2016)·8 citations
9. 09*

   The $K^{-}p\to f_1(1285)\Lambda$ reaction within an effective Lagrangian approach

   Ju-Jun Xie🇨🇳

   The production of the $f_1(1285)$ resonance in the reaction of $K^{-}p\to f_1(1285)\Lambda$ is studied within an effective Lagrangian approach. The production process is described by the $t$ channel $K^{\ast +}$ meson exchange. My theoretical approach is based on the results of chiral unitary theory where the $f_1(1285)$ resonance is dynamically generated from the single channel $\bar{K}{K}^{\ast }-c.c.$ interaction. The total and differential cross sections of the $K^{-}p\to f_1(1285)\Lambda$ reaction are evaluated. Within the coupling constant of the $f_1(1285)$ to $\bar{K}{K}^{\ast }$ channel obtained from the chiral unitary theory and a cut off parameter ${\Lambda }_c\sim 1.5$ GeV in the form factors, the experimental measurement can be reproduced. This production process would provide further evidence for the $\bar{K}{K}^{\ast }-c.c.$ nature of the $f_1(1285)$ state.

   ↳ nucl-thhep-exhep-phnucl-exPRC(2015)·15 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.