Wed·Jan 27, 2016Wednesday·January 27, 2016

1. 01*

   Deuteron-deuteron collision at 160 MeV

   G. Khatri🇵🇱 · W. Parol🇵🇱 · K. Bodek🇵🇱 · I. Ciepał🇵🇱 · B. Jamroz · N. Kalantar-Nayestanaki🇳🇱 · St. Kistryn🇵🇱 · B. Kłos · A. Kozela🇵🇱 · P. Kulessa🇵🇱 · A. Magiera🇵🇱 · I. Mazumdar and 8 other authors

   The experiment was carried out using BINA detector at KVI in Groningen. For the first time an extensive data analysis of the data collected in back part of the detector is presented, where a clusterization method is utilized for angular and energy information. We also present differential cross-sections for the (dd$\to$dpn) breakup reaction within \textit{dp} quasi-free scattering limit and their comparison with first calculations based on Single Scattering Approximation (SSA) approach.

   nucl-exActa Phys.Polon.B(2016)·3 citations
2. 02*

   Structure near $K^{-}$+$p$+$p$ threshold in the in-flight ${}^3$He$(K^{-},\Lambda p)n$ reaction

   J-PARC E15 Collaboration: Y. Sada🇯🇵 · S. Ajimura🇯🇵 · M. Bazzi🇮🇹 · G. Beer🇨🇦 · H. Bhang🇰🇷 · M. Bragadireanu🇷🇴 · P. Buehler🇦🇹 · L. Busso🇮🇹 · M. Cargnelli🇦🇹 · S. Choi🇰🇷 · C. Curceanu🇮🇹 · S. Enomoto🇯🇵 and 59 other authors

   To search for an S= -1 di-baryonic state which decays to $\Lambda p$, the ${}^3\mathrm{He}(K^{-},\Lambda p)n_{missing}$ reaction was studied at 1.0 GeV/$c$. Unobserved neutrons were kinematically identified from the missing mass $M_X$ of the ${}^3\mathrm{He}(K^{-},\Lambda p)X$ reaction in order to have a large acceptance for the $\Lambda pn$ final state. The observed $\Lambda pn$ events, distributed widely over the kinematically allowed region of the Dalitz plot, establish that the major component comes from a three nucleon absorption process. A concentration of events at a specific neutron kinetic energy was observed in a region of low momentum transfer to the $\Lambda p$. To account for the observed peak structure, the simplest S-wave pole was assumed to exist in the reaction channel, having Breit-Wigner form in energy and with a Gaussian form-factor. A minimum ${\chi }^2$ method was applied to deduce its mass $M_X=$ 2355 ${}_{-8}^{+6}$ (stat.) $\pm 12$ (syst.) MeV/c${}^2$, and decay-width ${\Gamma }_X=$ 110 ${}_{-17}^{+19}$ (stat.) $\pm 27$ (syst.) MeV/c${}^2$, respectively. The form factor parameter $Q_X\sim$ 400 MeV/$c$ implies that the range of interaction is about 0.5

   nucl-exPTEP(2016)·74 citations
3. 03*

   Upper limits for the production of the eta-mesic Helium in the dd ->3Henpi0 and dd -> 3Heppi- reactions

   M. Skurzok🇵🇱 · W. Krzemien🇵🇱 · O. Rundel🇵🇱 · P. Moskal🇵🇱

   We performed a search for 4He-eta bound state in dd -> 3Henpi0 and dd -> 3Heppi- reactions with the WASA-at-COSY facility using a ramped beam technique. The measurement was carried out with high statistics and high acceptance. The signature of eta-mesic nuclei was searched for by the measurement of the excitation functions in the vicinity of the eta production threshold for each of the considered channels. We did not observe the narrow structure which could be interpreted as a bound state. The preliminary upper limits of the total cross sections for the bound state production and decay varies from 21 nb to 36 nb for the dd -> 3Henpi0 channel, and from 5 nb to 9 nb for the dd -> 3Heppi- channel for the bound state width ranging from 5 to 50 MeV.

   nucl-exActa Phys.Polon.B(2016)·18 citations
4. 04*

   Measurement of elliptic flow of light nuclei at $\sqrt{s_{NN}}$ = 200, 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV at RHIC

   STAR Collaboration: L. Adamczyk · J. K. Adkins · G. Agakishiev · M. M. Aggarwal · Z. Ahammed · I. Alekseev · A. Aparin · D. Arkhipkin · E. C. Aschenauer · M. U. Ashraf · A. Attri · G. S. Averichev and 327 other authors

   We present measurements of 2${}^{nd}$ order azimuthal anisotropy ($v_2$) at mid-rapidity $(|y|<1.0)$ for light nuclei d, t, ${}^3$He (for $\sqrt{s_{NN}}$ = 200, 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV) and anti-nuclei $\bar{\mathrm{d}}$ ($\sqrt{s_{NN}}$ = 200, 62.4, 39, 27, and 19.6 GeV) and ${}^3\overline{\mathrm{He}}$ ($\sqrt{s_{NN}}$ = 200 GeV) in the STAR (Solenoidal Tracker at RHIC) experiment. The $v_2$ for these light nuclei produced in heavy-ion collisions is compared with those for p and $\bar{\mathrm{p}}$. We observe mass ordering in nuclei $v_2(p_T)$ at low transverse momenta ($p_T<2.0$ GeV/$c$). We also find a centrality dependence of $v_2$ for d and $\bar{\mathrm{d}}$. The magnitude of $v_2$ for t and ${}^3$He agree within statistical errors. Light-nuclei $v_2$ are compared with predictions from a blast wave model. Atomic mass number ($A$) scaling of light-nuclei $v_2(p_T)$ seems to hold for $p_T/A<1.5$ GeV/$c$. Results on light-nuclei $v_2$ from a transport-plus-coalescence model are consistent with the experimental measurements.

   nucl-exhep-exhep-phPRC(2016)·108 citations
5. 05*

   Cluster-shell competition and its effect on the $E0$ transition probability in ${}^{20}$Ne

   N. Itagaki🇯🇵 · H. Matsuno🇯🇵

   ${}^{20}$Ne has been known as a typical example of a nucleus with $\alpha$ cluster structure (${}^{16}$O+$\alpha$ structure). However according to the spherical shell model, the spin-orbit interaction acts attractively for four nucleons outside of the ${}^{16}$O core, and this spin-orbit effect cannot be taken into account in the simple $\alpha$ cluster models. We investigate how the $\alpha$ cluster structure competes with independent particle motions of these four nucleons. The antisymmetrized quasi-cluster model (AQCM) is a method to describe a transition from the $\alpha$ cluster wave function to the $jj$-coupling shell model wave function. In this model, the cluster-shell transition is characterized by only two parameters; $R$ representing the distance between clusters and $\Lambda$ describing the breaking of $\alpha$ clusters, and the contribution of the spin-orbit interaction, very important in the $jj$-coupling shell model, can be taken into account by changing $\alpha$ clusters to quasi clusters. In this article, based on AQCM, we apply ${}^{16}$O plus one quasi cluster model for ${}^{20}$Ne. Here we focus on the $E0$ transition matrix element, which has been known as the quantity characterizing the cluster structure. The $E0$ transition matrix elements are sensitive to the change of the wave functions from $\alpha$ cluster to $jj$-coupling shell model.

   ↳ nucl-thnucl-ex0 citations
6. 06*

   Precision measurement of the $\eta \to {\pi }^{+}{\pi }^{-}{\pi }^0$ Dalitz plot distribution with the KLOE detector

   KLOE-2 Collaboration: A. Anastasi🇮🇹 · D. Babusci🇮🇹 · G. Bencivenni🇮🇹 · M. Berlowski🇵🇱 · C. Bloise🇮🇹 · F. Bossi🇮🇹 · P. Branchini🇮🇹 · A. Budano🇮🇹 · L. Caldeira Balkeståhl🇸🇪 · B. Cao🇸🇪 · F. Ceradini🇮🇹 · P. Ciambrone🇮🇹 and 51 other authors

   Using $1.6$ fb${}^{-1}$ of $e^{+}{e}^{-}\to \varphi \to \eta \gamma$ data collected with the KLOE detector at DA$\Phi$NE, the Dalitz plot distribution for the $\eta \to {\pi }^{+}{\pi }^{-}{\pi }^0$ decay is studied with the world's largest sample of $\sim 4.7\cdot 10^6$ events. The Dalitz plot density is parametrized as a polynomial expansion up to cubic terms in the normalized dimensionless variables $X$ and $Y$. The experiment is sensitive to all charge conjugation conserving terms of the expansion, including a $g{X}^{2}Y$ term. The statistical uncertainty of all parameters is improved by a factor two with respect to earlier measurements.

   ↳ hep-exnucl-exJHEP(2016)·69 citations
7. 07*

   Kinetic freeze-out temperature and flow velocity extracted from transverse momentum spectra of final-state light flavor particles produced in collisions at RHIC and LHC

   Hua-Rong Wei🇨🇳 · Fu-Hu Liu🇨🇳 · Roy A. Lacey🇺🇸

   The transverse momentum spectra of final-state light flavor particles produced in proton-proton (p-p), copper-copper (Cu-Cu), gold-gold (Au-Au), lead-lead (Pb-Pb), and proton-lead (p-Pb) collisions for different centralities at relativistic heavy ion collider (RHIC) and large hadron collider (LHC) energies are studied in the framework of a multisource thermal model. The experimental data measured by the STAR, CMS, and ALICE Collaborations are consistent with the results calculated by the multi-component Erlang distribution and Tsallis Statistics. The effective temperature and real temperature (kinetic freeze-out temperature) of interacting system at the stage of kinetic freeze-out, the mean transverse flow velocity and mean flow velocity of particles, and the relationships between them are extracted. The dependences of effective temperature and mean (transverse) momentum on rest mass, moving mass, centrality, and center-of-mass energy, and the dependences of kinetic freeze-out temperature and mean (transverse) flow velocity on centrality, center-of-mass energy, and system size are obtained.

   ↳ hep-phnucl-exnucl-thEPJA(2016)·43 citations
8. 08*

   Event patterns extracted from transverse momentum and rapidity spectra of Z bosons and quarkonium states produced in pp and Pb-Pb collisions at LHC

   Ya-Hui Chen🇨🇳 · Fu-Hu Liu🇨🇳 · Roy A. Lacey🇺🇸

   Transverse momentum ($p_T$) and rapidity ($y$) spectra of $Z$ bosons and quarkonium states (some charmonium $c\bar{c}$ mesons such as $J/\psi$ and $\psi (2S)$, and some bottomonium $b\bar{b}$ mesons such as ${\rm Y}(1S)$, ${\rm Y}(2S)$, and ${\rm Y}(3S)$) produced in proton-proton ($pp$) and lead-lead (Pb-Pb) collisions at the large hadron collider (LHC) are uniformly described by a hybrid model of two-component Erlang distribution for $p_T$ spectrum and two-component Gaussian distribution for $y$ spectrum. The former distribution results from a multisource thermal model, and the latter one results from the revised Landau hydrodynamic model. The modelling results are in agreement with the experimental data measured in $pp$ collisions at center-of-mass energies $\sqrt{s}=2.76$ and 7 TeV, and in Pb-Pb collisions at center-of-mass energy per nucleon pair $\sqrt{s_{NN}}=2.76$ TeV. Based on the parameter values extracted from $p_T$ and $y$ spectra, the event patterns (particle scatter plots) in two-dimensional $p_T$-$y$ space and in three-dimensional velocity space are obtained.

   ↳ hep-phhep-exnucl-exnucl-thAdv.High Energy Phys.(2016)·6 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.