Tue·Oct 19, 2021Tuesday·October 19, 2021

1. 01*

   Shapes, Softness and Non-Yrast Collectivity in 186W

   V. S. Prasher🇺🇸 · A. J. Mitchell🇦🇺 · C. J. Lister🇺🇸 · P. Chowdhury🇺🇸 · L. Afanasieva🇺🇸 · M. Albers🇺🇸 · C. J. Chiara🇺🇸 · M. P. Carpenter🇺🇸 · D. Cline🇺🇸 · N. D'Olympia🇺🇸 · C. J. Guess🇺🇸 · A. B. Hayes🇺🇸 and 14 other authors

   Non-yrast, excited states in neutron-rich ${}^{186}$W were populated via inelastic-scattering reactions using beams of ${}^{136}$Xe nuclei accelerated to 725 and 800 MeV. Levels populated in the reactions were investigated via particle-$\gamma$ coincidence techniques using the Gammasphere array of High-Purity Germanium detectors and the compact heavy-ion counter, CHICO2. The $K^{\pi }=2^{+}$ ($\gamma$), $K^{\pi }=0^{+}$ and $K^{\pi }=2^{-}$ (octupole) rotational side bands were extended to spins $14\hslash$, $12\hslash$, and $13\hslash$, respectively. A staggering pattern observed in the energies of levels in the $K^{\pi }=2^{+}$ band was found to be consistent with a potential that gets softer to vibration in the $\gamma$ degree of freedom with increasing spin. The odd-even staggering of states in the $K^{\pi }=2^{-}$ band was found to exhibit a phase opposite to that seen in the $\gamma$ band; an effect most probably associated with Coriolis coupling to other, unobserved octupole vibrational bands in ${}^{186}$W.

   nucl-exnucl-thPRC(2021)·1 citation
2. 02*

   Measurement of the EMC effect in light and heavy nuclei

   J. Arrington🇺🇸 · J. Bane🇺🇸 · A. Daniel🇺🇸 · N. Fomin🇺🇸 · D. Gaskell🇺🇸 · J. Seely🇺🇸 · R. Asaturyan🇦🇲 · F. Benmokhtar🇺🇸 · W. Boeglin🇺🇸 · P. Bosted🇺🇸 · M.H.S. Bukhari🇸🇦 · M.E. Christy🇺🇸 and 45 other authors

   Inclusive electron scattering from nuclear targets has been measured to extract the nuclear dependence of the inelastic cross section in Hall C at the Thomas Jefferson National Accelerator facility. Results are presented for 2H, 3He, 4He, 9B, 12C, 63Cu and 197Au at an incident electron beam energy of 5.77 GeV for a range of momentum transfer from Q^2 = 2 to 7 (GeV/c)^2. These data improve the precision of the existing measurements of the EMC effect in the nuclear targets at large x, and allow for more detailed examinations of the A dependence of the EMC effect.

   nucl-exnucl-thPRC(2021)·37 citations
3. 03*

   Insight from the elliptic flow of identified hadrons measured in relativistic heavy-ion collisions

   Prabhupada Dixit🇮🇳 · Md. Nasim🇮🇳

   In this paper, we have discussed the transverse momentum dependence of elliptic flow measured in relativistic heavy-ion collisions. The transverse momentum dependence of the number of constituent quarks ($n_q$) scaled $v_2$ is obtained for all the measured identified hadrons. The $n_q$ scaled $\varphi$ $v_2$ is found to be similar to $n_q$ scaled $\Omega$ $v_2$. This indicates that both $\varphi$ and $\Omega$ are produced through quark recombination at RHIC energies. We also find $n_q$ scaled proton $v_2$ ($v_2$ of light quarks) is higher than $n_q$ scaled $\varphi$ and $\Omega$ $v_2$ ($v_2$ of strange quarks) at $p_T/n_q$ $<$ 1.0 GeV/c. This can be explained by considering quark $v_2$ is proportional to its transverse kinetic energy considering mass of deconfined light and strange quarks equal to $\sim$4 MeV and $\sim$ 140 MeV, respectively.

   nucl-exhep-exhep-phnucl-thIJMPE(2022)·0 citations
4. 04*

   Charm and beauty isolation from heavy flavor decay electrons in p+p and Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV at LHC

   Dongsheng Li🇨🇳 · Fan Si🇨🇳 · Yidan Zhao🇨🇳 · Pengyu Zhou🇨🇳 · Yifei Zhang🇨🇳 · Xiujun Li🇨🇳 · Chengxi Yang🇨🇳

   We present an analysis on the heavy flavor hadron decay electrons with charm and beauty contributions decomposed via a data driven method in p+p and Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV at LHC. The transverse momentum $p_{\mathrm{T}}$ spectra, nuclear modification factor $R_{\mathrm{AA}}$ and azimuthal anisotropic flow $v_2$ distributions of electrons from charm and beauty decays are obtained. We find that the electron $R_{\mathrm{AA}}$ from charm ($R_{\mathrm{AA}}^{\mathrm{c}\to \mathrm{e}}$) and beauty ($R_{\mathrm{AA}}^{\mathrm{b}\to \mathrm{e}}$) decays are suppressed at $p_{\mathrm{T}}$ $>$ 2.0 and $p_{\mathrm{T}}$ $>$ 3.0 GeV/$c$ in Pb+Pb collisions, respectively, which indicates that charm and beauty interact with and lose their energy in the hot-dense medium. A less suppression of electron $R_{\mathrm{AA}}$ from beauty decays than that from charm decays at 2.0 $<$ $p_{\mathrm{T}}$ $<$ 8.0 GeV/$c$ is observed, which is consistent with the mass-dependent partonic energy loss scenario. A non-zero electron $v_2$ from beauty decays ($v_2^{\mathrm{b}\to \mathrm{e}}$) is observed and in good agreement with ALICE measurement. At low $p_{\mathrm{T}}$ region from 1.0 to 3.0 GeV/$c$, a discrepancy between RHIC and LHC results is observed with 68\% confidence level, which suggests different degree of thermalization of beauty quark under different temperatures of the medium. At 3.0 GeV/$c$ $<$ $p_{\mathrm{T}}$ $<$ 7.0 GeV/$c$, $v_2^{\mathrm{b}\to \mathrm{e}}$ deviates from a number-of-constituent-quark (NCQ) scaling hypothesis, which favors that beauty quark is unlikely thermalized in heavy-ion collisions at LHC energy.

   nucl-exPLB(2022)·3 citations
5. 05*

   The cross-section measurement for the ${}^3\text{H}(e,e^{\prime }{K}^{+})nn\Lambda$ reaction

   K. N. Suzuki🇯🇵 · T. Gogami🇯🇵 · B. Pandey🇺🇸 · K. Itabashi🇯🇵 · S. Nagao🇯🇵 · K. Okuyama · S. N. Nakamura🇯🇵 · L. Tang🇺🇸 · D. Abrams🇺🇸 · T. Akiyama🇯🇵 · D. Androic🇭🇷 · K. Aniol🇺🇸 and 71 other authors

   The small binding energy of the hypertrition leads to predictions of non-existence of bound hypernuclei for isotriplet three-body systems such as $nn\Lambda$. However, invariant mass spectroscopy at GSI has reported events that may be interpreted as the bound $nn\Lambda$ state. The $nn\Lambda$ state was sought by missing-mass spectroscopy via the $(e,e^{\prime }{K}^{+})$ reaction at Jefferson Lab's experimental Hall A. The present experiment has higher sensitivity to the $nn\Lambda$-state investigation in terms of better precision by a factor of about three. The analysis shown in this article focuses on the derivation of the reaction cross-section for the ${}^3\mathrm{H}({\gamma }^{\ast },K^{+})\text{X}$ reaction. Events that were detected in an acceptance, where a Monte Carlo simulation could reproduce the data well ($|\delta p/p|<4\%$), were analyzed to minimize the systematic uncertainty. No significant structures were observed with the acceptance cuts, and the upper limits of the production cross-section of the $nn\Lambda$ state were obtained to be $21$ and $31nb/sr$ at the $90\%$ confidence level when theoretical predictions of $(-B_{\Lambda },\Gamma )=(0.25,0.8)$ and $(0.55,4.7)$ MeV, respectively, were assumed. The cross-section result provides valuable information for examining the existence of $nn\Lambda$.

   nucl-exnucl-thPTEP(2022)·13 citations
6. 06*

   Prompt D${}^0$, D${}^{+}$, and D${}^{\ast +}$ production in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV

   ALICE Collaboration

   The production of prompt D${}^0$, D${}^{+}$, and D${}^{\ast +}$ mesons was measured at midrapidity (|y|< 0.5) in Pb-Pb collisions at the centre-of-mass energy per nucleon-nucleon pair $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV with the ALICE detector at the LHC. The D mesons were reconstructed via their hadronic decay channels and their production yields were measured in central (0-10%) and semicentral (30-50%) collisions. The measurement was performed up to a transverse momentum ($p_{\mathrm{T}}$) of 36 or 50 GeV/$c$ depending on the D meson species and the centrality interval. For the first time in Pb-Pb collisions at the LHC, the yield of D${}^0$ mesons was measured down to $p_{\mathrm{T}}$ = 0, which allowed a model-independent determination of the $p_{\mathrm{T}}$-integrated yield per unit of rapidity (d$N$/d$y$). A maximum suppression by a factor 5 and 2.5 was observed with the nuclear modification factor ($R_{\mathrm{AA}}$) of prompt D mesons at $p_{\mathrm{T}}$ = 6-8 GeV/$c$ for the 0-10% and 30-50% centrality classes, respectively. The D-meson $R_{\mathrm{AA}}$ is compared with that of charged pions, charged hadrons, and J/$\psi$ mesons as well as with theoretical predictions. The analysis of the agreement between the measured $R_{\mathrm{AA}}$, elliptic ($v_2$) and triangular ($v_3$) flow, and the model predictions allowed us to constrain the charm spatial diffusion coefficient $D_s$. Furthermore the comparison of $R_{\mathrm{AA}}$ and $v_2$ with different implementations of the same models provides an important insight into the role of radiative energy loss as well as charm quark recombination in the hadronisation mechanisms.

   nucl-exhep-exJHEP(2022)·208 citations
7. 07*

   Evidence for a QCD accelerator in relativistic heavy-ion collisions

   L.C. Bland🇺🇸 · E.J. Brash🇺🇸 · H.J. Crawford🇺🇸 · A. Drees🇺🇸 · J. Engelage🇺🇸 · C. Folz🇺🇸 · E. Judd🇺🇸 · X. Li🇺🇸 · N.G. Minaev🇷🇺 · R.N. Munroe🇺🇸 · L. Nogach🇷🇺 · A. Ogawa🇺🇸 and 8 other authors

   We report measurements of forward jets produced in Cu+Au collisions at $\sqrt{s_{NN}}=200$ GeV at the Relativistic Heavy Ion Collider. The jet-energy distributions extend to energies much larger than expected by Feynman scaling. This constitutes the first clear evidence for Feynman-scaling violations in heavy-ion collisions. Such high-energy particle production has been in models via QCD string interactions, but so far is untested by experiment. One such model calls this a hadronic accelerator. Studies with a particular heavy-ion event generator (HIJING) show that photons and mesons exhibit such very high-energy production in a heavy-ion collision, so {\it QCD accelerator} appropriately captures the physics associated with such QCD string interactions. All models other than HIJING used for hadronic interactions in the study of extensive air showers from cosmic rays either do not include these QCD string interactions, or have smaller effects from the QCD accelerator.

   nucl-exastro-ph.HEPRC(2022)·3 citations
8. 08*

   Measurements of ${}_{\Lambda }^3\mathrm{H}$ and ${}_{\Lambda }^4\mathrm{H}$ Lifetimes and Yields in Au+Au Collisions in the High Baryon Density Region

   STAR Collaboration: M. S. Abdallah · B. E. Aboona · J. Adam · L. Adamczyk · J. R. Adams · J. K. Adkins · G. Agakishiev · I. Aggarwal · M. M. Aggarwal · Z. Ahammed · I. Alekseev · D. M. Anderson and 390 other authors

   We report precision measurements of hypernuclei ${}_{\Lambda }^3\mathrm{H}$ and ${}_{\Lambda }^4\mathrm{H}$ lifetimes obtained from Au+Au collisions at \snn = 3.0\,GeV and 7.2\,GeV collected by the STAR experiment at RHIC, and the first measurement of ${}_{\Lambda }^3\mathrm{H}$ and ${}_{\Lambda }^4\mathrm{H}$ mid-rapidity yields in Au+Au collisions at \snn = 3.0\,GeV. ${}_{\Lambda }^3\mathrm{H}$ and ${}_{\Lambda }^4\mathrm{H}$, being the two simplest bound states composed of hyperons and nucleons, are cornerstones in the field of hypernuclear physics. Their lifetimes are measured to be $221\pm 15(stat.)\pm 19(syst.)$\,ps for ${}_{\Lambda }^3\mathrm{H}$ and $218\pm 6(stat.)\pm 13(syst.)$\,ps for ${}_{\Lambda }^4\mathrm{H}$. The $p_T$-integrated yields of ${}_{\Lambda }^3\mathrm{H}$ and ${}_{\Lambda }^4\mathrm{H}$ are presented in different centrality and rapidity intervals. It is observed that the shape of the rapidity distribution of ${}_{\Lambda }^4\mathrm{H}$ is different for 0--10\% and 10--50\% centrality collisions. Thermal model calculations, using the canonical ensemble for strangeness, describes the ${}_{\Lambda }^3\mathrm{H}$ yield well, while underestimating the ${}_{\Lambda }^4\mathrm{H}$ yield. Transport models, combining baryonic mean-field and coalescence (JAM) or utilizing dynamical cluster formation via baryonic interactions (PHQMD) for light nuclei and hypernuclei production, approximately describe the measured ${}_{\Lambda }^3\mathrm{H}$ and ${}_{\Lambda }^4\mathrm{H}$ yields. Our measurements provide means to precisely assess our understanding of the fundamental baryonic interactions with strange quarks, which can impact our understanding of more complicated systems involving hyperons, such as the interior of neutron stars or exotic hypernuclei.

   nucl-exPRL(2022)·94 citations
9. 09*

   Track Recognition for the $\Delta E-E$ Telescopes with Silicon Strip Detectors

   Fenhai Guan🇨🇳 · Yijie Wang🇨🇳 · Xinyue Diao🇨🇳 · Yuhao Qin🇨🇳 · Zhi Qin🇨🇳 · Dong Guo🇨🇳 · Qianghua Wu · Dawei Si · Sheng Xiao · Boyuan Zhang🇨🇳 · Yaopeng Zhang🇺🇸 · Xuan Zhao🇺🇸 · Zhigang Xiao🇨🇳

   For the high granularity and high energy resolution, Silicon Strip Detector (SSD) is widely applied in assembling telescopes to measure the charged particles in heavy ion reactions. In this paper, we present a novel method to achieve track recognition in the SSD telescopes of the Compact Spectrometer for Heavy Ion Experiment (CSHINE). Each telescope consists of a single-sided silicon strip detector (SSSSD) and a double-sided silicon strip detector (DSSSD) backed by $3\times 3$ CsI(Tl) crystals. Detector calibration and track reconstruction are implemented. Special decoding algorithm is developed for the multi-track recognition procedure to deal with the multi-hit effect convoluted by charge sharing and the missing signals with certain probability. It is demonstrated that the track recognition efficiency of the method is approximately 90\% and 80\% for the DSSSD-CsI and SSSSD-DSSSD events, respectively.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2022)·17 citations
10. 10*

    Characterization of plastic scintillator bars using fast neutrons from D-D and D-T reactions

    R. Dey🇮🇳 · P. K. Netrakanti🇮🇳 · D. K. Mishra🇮🇳 · S. P. Behera🇮🇳 · D. Mulmule🇮🇳 · T. Patel · P. S. Sarkar · V. Jha🇮🇳 · L. M. Pant🇮🇳

    We report results of fast neutron response in plastic scintillator (PS) bars from deuterium-deuterium (D-D) and deuterium-tritium (D-T) reactions using Purnima Neutron Generator Facility, BARC, Mumbai. These measurements are useful in context of Indian Scintillator Matrix for Reactor Anti-Neutrino (ISMRAN) detection, an array of 10x10 PS bars, used to measure reactor anti-neutrinos through inverse beta decay (IBD) signal. ISMRAN detector, an above-ground experiment close to the reactor core (~13m), deals with an active fast neutron background inside the reactor hall. A good understanding of fast neutron response in PS bars is an essential pre-requisite for suppression and discrimination of fast neutron background from IBD events. A monoenergetic neutron beam from the fusion reaction of D-D at 2.45 MeV and D-T at 14.1 MeV are used to characterize the energy response in these bars. The neutron energy response function has been simulated using the GEANT4 package and are compared with the measured data. A reasonable agreement of deposited energies by fast neutrons in PS bars between data and simulation are obtained for these reactions. The ratio of energy deposition in adjacent bars is used to discriminate between prompt IBD, fast neutron and neutron capture cascade gamma events.

    ↳ physics.ins-detnucl-exJINST(2021)·5 citations
11. 11*

    Protonium annihilation densities in a unitary coupled channel model

    Emanuel Ydrefors🇧🇷 · Jaume Carbonell🇫🇷

    We consider a unitary coupled channel model to describe the low energy proton-antiproton scattering and the lower Coulomb-like protonium states. The existence of deeper quasi-bound states of nuclear nature is found to be a consequence of the experimental data. The properties of these states as well as the protonium annihilation densities are described and the difference with respect to the optical models description are manifested.

    ↳ nucl-thhep-phnucl-exEPJA(2021)·4 citations
12. 12*

    OuroborosBEM: A fast multi-GPU microscopic Monte Carlo simulation for gaseous detectors and charged particle dynamics

    G. Quéméner🇫🇷 · S. Salvador🇫🇷

    The design of gaseous detectors for accelerator, particle and nuclear physics requires simulations relying on multi-physics aspects. In fact, these simulations deal with the dynamics of a large number of charged particles interacting in a gaseous medium immersed in the electric field generated by a more or less complex assembly of electrodes and dielectric materials. We report here on a homemade software, called OUROBOROSBEM, able to tackle the different features involved in such simulations. After solving the electrostatic problem for which a solver based on the boundary element method (BEM) has been implemented, particles are tracked and will microscopically interact with the gas medium. Dynamical effects have been included such as the electron-ion recombination process, the charging-up of the dielectric materials and other space charge effects that might alter the detector performances. These were made possible thanks to the nVidia CUDA language specifically optimised to run on Graphical Processor Units (GPUs) to minimize the computing times. Comparisons of the results obtained for parallel plate avalanche counters and GEM detectors to literature data on swarm parameters fully validate the performances of OUROBOROSBEM. Moreover, we were able to precisely reproduce the measured gains of single and double GEM detectors as a function of the applied voltage.

    ↳ physics.ins-detnucl-exJINST(2022)·3 citations
13. 13*

    First Results with the ANET Compact Thermal Neutron Collimator

    Oriol Sans-Planell🇮🇹 · Marco Costa🇮🇹 · Elisabetta Durisi🇮🇹 · Ettore Mafucci🇮🇹 · Luca Menzio🇮🇹 · Valeria Monti🇮🇹 · Lorenzo Visca🇮🇹 · Francesco Grazzi🇮🇹 · Roberto Bedogni🇮🇹 · Saverio Altieri🇮🇹

    This paper presents the first determination of the spatial resolution of the ANET Compact Neutron Collimator, obtained with a measuring campaign at the LENA Mark-II TRIGA reactor in Pavia. This novel collimator consists of a sequence of collimating and absorbing channels organised in a chessboard-like geometry. It has a scalable structure both in length and in the field of view. It is characterized by an elevated collimation power within a limited length. Its scalability and compactness are added values with respect to traditional collimating system. The prototype tested in this article is composed of 4 concatenated stages, each 100mm long, with a channel width of 2.5mm, delivering a nominal L/D factor of 160. This measuring campaign illustrates the use of the ANET collimator and its potential application in neutron imaging for facilities with small or medium size neutron sources.

    ↳ physics.ins-detnucl-exphysics.acc-phJINST(2021)·2 citations
14. 14*

    Probing dense matter physics with transiently-accreting neutron stars: the case of source MXB 1659-29

    Melissa Mendes🇩🇪 · Farrukh J. Fattoyev🇺🇸 · Andrew Cumming · Charles Gale🇨🇦

    Recent observational data on transiently-accreting neutron stars has unequivocally shown fast-cooling sources, such as in the case of neutron star MXB 1659-29. Previous calculations have estimated its total neutrino luminosity and heat capacity, as well as suggested that direct Urca reactions take place in $1\%$ of the volume of the core. In this paper, we reproduce the inferred luminosity of this source with detailed models of equations of state (EOS) and nuclear pairing gaps. We show that three superfluidity gap models are inconsistent with data for all EOS and another three are disfavoured because of fine tuning arguments. We also calculate the total heat capacity for all constructed stars and show that independent observations of mass and luminosity could set constraints on the core superfluidity of a source as well as the density slope of the symmetry energy, L. This is an important step towards defining a universal equation of state for neutron stars and therefore, towards a better understanding of the phase diagram of asymmetric matter at high densities.

    ↳ nucl-thastro-ph.HEnucl-ex2 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.