Mon·Dec 24, 2018Monday·December 24, 2018

1. 01*

   First observation of unbound ${}^{11}$O, the mirror of the halo nucleus ${}^{11}$Li

   T.B. Webb🇺🇸 · S.M. Wang🇺🇸 · K.W. Brown🇺🇸 · R.J. Charity🇺🇸 · J.M. Elson🇺🇸 · J. Barney🇺🇸 · G. Cerizza🇺🇸 · Z. Chajecki🇺🇸 · J. Estee🇺🇸 · D.E.M. Hoff🇺🇸 · S.A. Kuvin · W.G. Lynch🇺🇸 and 14 other authors

   The structure of the extremely proton-rich nucleus ${}_8^{11}$O${}_3$, the mirror of the two-neutron halo nucleus ${}_3^{11}$Li${}_8$, has been studied experimentally for the first time. Following two-neutron knockout reactions with a ${}^{13}$O beam, the ${}^{11}$O decay products were detected after two-proton emission and used to construct an invariant-mass spectrum. A broad peak of width $\sim$3\,MeV was observed. Within the Gamow coupled-channel approach, it was concluded that this peak is a multiplet with contributions from the four-lowest ${}^{11}$O resonant states: $J^{\pi }$=3/2${}_1^{-}$, 3/2${}_2^{-}$, 5/2${}_1^{+}$, and 5/2${}_2^{+}$. The widths and configurations of these states show strong, non-monotonic dependencies on the depth of the $p$-${}^9$C potential. This unusual behavior is due to the presence of a broad threshold resonant state in ${}^{10}$N, which is an analog of the virtual state in ${}^{10}$Li in the presence of the Coulomb potential. After optimizing the model to the data, only a moderate isospin asymmetry between ground states of ${}^{11}$O and ${}^{11}$Li was found.

   nucl-exnucl-thPRL(2019)·45 citations
2. 02*

   Towards Neutron Capture on Exotic Nuclei: Demonstrating $(d,p\gamma )$ as a Surrogate Reaction for $(n,\gamma )$

   A. Ratkiewicz · J. A. Cizewski🇺🇸 · J. E. Escher🇺🇸 · G. Potel🇺🇸 · J. T. Burke · R. J. Casperson · M. McCleskey · R. A. E. Austin🇨🇦 · S. Burcher🇺🇸 · R. O. Hughes · B. Manning🇺🇸 · S. D. Pain🇺🇸 and 6 other authors

   The neutron-capture reaction plays a critical role in the synthesis of the elements in stars and is important for societal applications including nuclear power generation and stockpile-stewardship science. However, it is difficult - if not impossible - to directly measure neutron capture cross sections for the exotic, short-lived nuclei that participate in these processes. In this Letter we demonstrate a new technique which can be used to indirectly determine neutron-capture cross sections for exotic systems. This technique makes use of the $(d,p)$ transfer reaction, which has long been used as a tool to study the structure of nuclei. Recent advances in reaction theory, together with data collected using this reaction, enable the determination of neutron-capture cross sections for short-lived nuclei. A benchmark study of the ${}^{95}$Mo$(d,p)$ reaction is presented, which illustrates the approach and provides guidance for future applications of the method with short-lived isotopes produced at rare isotope accelerators.

   nucl-exPRL(2019)·57 citations
3. 03*

   PHENIX results on system size dependence of J/$\psi$ nuclear modification in $p$,$d$, ${}^3$He+A collisions at $\sqrt{s_{NN}}$=200 GeV

   J. Matthew Durham (for the PHENIX collaboration)🇺🇸

   The dissociation of quarkonia in the medium created in heavy ion collisions is still one of the most debated topics in the heavy ion community. Progress in understanding the effect relies on a broad range of measurements in collisions with different nuclear sizes, covering a broad rapidity range. This presentation will report the $J/\psi$ measurements performed by the PHENIX collaboration at forward and backward rapidities of 1.2 $<|y|<$ 2.2 in $p$+Al, $p$+Au, and ${}^3$He+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV, and the corresponding nuclear modification factors.

   nucl-exPoS(2018)·1 citation
4. 04*

   Fine structure of giant resonances: What can be learned

   Peter von Neumann-Cosel🇩🇪

   Fine structure of giant resonances (GR) has been established in recent years as a global phenomenon across the nuclear chart and for different types of resonances. A quantitative description of the fine structure in terms of characteristic scales derived by wavelet techniques is discussed. By comparison with microscpic calculations of GR strength distributions one can extract information on the role of different decay mechanisms contributing to the width of GRs. The observed cross-section fluctuations contain information on the level density (LD) of states with a given spin and parity defined by the multipolarity of the GR.

   nucl-exnucl-thActa Phys.Polon.B(2019)·1 citation
5. 05*

   Gamma strength functions and the Brink-Axel hypothesis

   Peter von Neumann-Cosel🇩🇪

   Experimental tests of the Brink-Axel hypothesis relating gamma strength functions (GSF) deduced from absorption and emission experiments are discussed. High-resolution inelastic proton scattering at energies of a few hundred MeV and at very forwrd angles including $0^{\circ }$ presents a new approach to test the validity of the BA hypothesis in the energy region of the pygmy dipole resonance. Such data not only provide the GSF but also the level density and thus permit an independent test of their model-dependent decomposition in the Oslo method.

   nucl-exnucl-thSpringer Proc.Phys.(2020)·0 citations
6. 06*

   Nuclear track emulsion in search for the Hoyle-state in dissociation of relativistic ${}^{12}$C nuclei

   D.A. Artemenkov🇷🇺 · V. Bradnova🇷🇺 · G.I. Britvich · E. Firu🇷🇴 · M. Haiduc🇷🇴 · V.A. Kalinin · S.P. Kharlamov · N.K. Kornegrutsa · M. Yu Kostin · A.V. Maksimov · E. Mitsevae · A. Neagu🇷🇴 and 7 other authors

   Production of ensembles of $\alpha$-particle triples associated with the Hoyle state (the second excited state of the ${}^{12}$C nucleus) in peripheral dissociation of relativistic ${}^{12}$C nuclei is studied. Stacks of nuclear track emulsion pellicles exposed to ${}^{12}$C with an energy from hundreds MeV to a few GeV per nucleon serve as the material for studies. The Hoyle state decays are reconstructed via measurement of emission angles of $\alpha$ particles with the precision sufficient for identification of the unstable ${}^8$Be nucleus. The estimate of the contribution of Hoyle's state to the ${}^{12}$C $\to$ 3$\alpha$ dissociation is 10-15\%.

   nucl-exRadiat.Meas.(2018)·10 citations
7. 07*

   The effect of the neutron and proton numbers ratio in colliding nuclei at formation of the evaporation residues in the ${}^{34}$S+${}^{208}$Pb and ${}^{36}$S+${}^{206}$Pb reactions

   A.K. Nasirov (1,2)🇷🇺 · B.M. Kayumov (2) · G. Mandaglio (3,4)🇮🇹 · G. Giardina (5)🇮🇹 · K. Kim (6)🇰🇷 · Y. Kim (6)((1) BLTP, Joint Institute for Nuclear Research, Dubna, Russia, (2) Institute of Nuclear Physics, Ulugbek, Tashkent, Uzbekistan,(3) Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, University of Messina, Messina, Italy, (4) INFN Sezione di Catania, Catania, Italy, (5) Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, University of Messina, Messina, Italy, (6) Rare Isotope Science Project, Institute for Basic Science, Daejeon, Republic of Korea)🇺🇸

   The difference between observed cross sections of the evaporation residues (ER) of the ${}^{34}$S+${}^{208}$Pb and ${}^{36}$S+${}^{206}$Pb reactions formed in the 2n and 3n channels has been explained by two reasons related with the entrance channel characteristics of these reactions. The first reason is that the capture cross section of the latter reaction is larger than the one of the ${}^{34}$S+${}^{208}$Pb reaction since the nucleus-nucleus potential is more attractive in the ${}^{36}$S+${}^{206}$Pb reaction due to two more neutrons in isotope ${}^{36}$S. The second reason is the difference in the heights of the intrinsic fusion barrier $B_{\mathrm{fus}}^{\ast }$ appearing on the fusion trajectory by nucleon transfer between nuclei of the DNS formed after the capture. The value of $B_{\mathrm{fus}}^{\ast }$ calculated for the ${}^{34}$S+${}^{208}$Pb reaction is higher than the one obtained for the ${}^{36}$S+${}^{206}$Pb reaction. This fact has been caused by the difference between the $N/Z$-ratios in the light fragments of the DNS formed during the capture in these reactions. The $N/Z$-ratio has been found by solution of the transport master equations for the proton and neutron distributions between fragments of the DNS formed at capture with the different initial neutron numbers $N=18$ and $N=20$ for the reactions with the ${}^{34}$S and ${}^{36}$S, respectively.

   ↳ nucl-thnucl-exEPJA(2019)·18 citations
8. 08*

   Possible non-prompt photons in $pp$ collisions and their effects in $AA$ analyses

   Akihiko Monnai🇯🇵

   Direct photons are a powerful tool for elucidating the properties of the hot QCD matter in heavy-ion collisions. They are conventionally estimated by assuming prompt photon contributions in proton-proton collisions and thermal and prompt photon contributions in heavy-ion collisions. On the other hand, there could also be other sources of photons such as pre-equilibrium photons. I investigate prompt, pre-equilibrium and thermal photons and their effects on the direct photon $p_T$ spectra at CERN Large Hadron Collider energies.

   ↳ nucl-thhep-phnucl-exPoS(2019)·8 citations
9. 09*

   Probing Generalized Parton Distributions through the photoproduction of a $\gamma \pi$ pair

   G. Duplančić🇭🇷 · K. Passek-Kumerički🇭🇷 · B. Pire🇫🇷 · L. Szymanowski🇵🇱 · S. Wallon🇫🇷

   We study in the framework of collinear QCD factorization the photoproduction of a $\gamma \pi$ pair with a large invariant mass and a small transverse momentum, as a new way to access generalized parton distributions. In the kinematics of JLab 12-GeV, we demonstrate the feasibility of this measurement and show the extreme sensitivity of the unpolarized cross section to the axial quark GPDs.

   ↳ hep-phhep-exnucl-exnucl-thActa Phys.Polon.Supp.(2019)·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.