Tue·May 28, 2019Tuesday·May 28, 2019

1. 01*

   Structure of ${}^{38}$Cl and the quest for a comprehensive shell model interaction

   R. S. Lubna (1) · K. Kravvaris (1 and 2)🇺🇸 · S. L. Tabor (1) · Vandana Tripathi (1) · A. Volya (1)🇺🇸 · E. Rubino (1)🇺🇸 · J. M. Allmond (3)🇺🇸 · B. Abromeit (1) · L. T. Baby (1)🇺🇸 · T. C. Hensley (1) ((1) Florida State University, Tallahassee, (2) Lawrence Livermore National Laboratory, Livermore, (3) Physics Division, Oak Ridge National Laboratory)

   The higher-spin structure of ${}^{38}$Cl ($N=21$) was investigated following the ${}^{26}$Mg(${}^{14}$C, $pn$) reaction at 30 and 37 MeV beam energies. The outgoing protons were detected in an $E-\Delta E$ Si telescope placed at 0${}^{\circ }$ close to the target with a Ta beam stopper between the target and telescope. Multiple $\gamma$ rays were detected in time coincidence with the protons using an enhanced version of the FSU $\gamma$ detection array. The level scheme was extended up to 8420 keV with a likely spin of 10 $\hslash$. A new multishell interaction was developed guided by the experimental information. This FSU interaction was built by fitting to the energies of 270 experimental states from ${}^{13}$C to ${}^{51}$Ti. Calculations using the FSU interaction reproduce observed properties of ${}^{38}$Cl rather well, including the spectroscopic factors. The interaction has been successfully used to interpret the $1p1h$ and $2p2h$ configurations in some nearby nuclei as well.

   nucl-exnucl-thPRC(2019)·35 citations
2. 02*

   First measurement of near-threshold J/$\psi$ exclusive photoproduction off the proton

   The GlueX Collaboration: A. Ali🇩🇪 · M. Amaryan🇺🇸 · E. G. Anassontzis🇬🇷 · A. Austregesilo🇺🇸 · M. Baalouch🇺🇸 · F. Barbosa🇺🇸 · J. Barlow🇺🇸 · A. Barnes🇺🇸 · E. Barriga🇺🇸 · T. D. Beattie🇨🇦 · V. V. Berdnikov🇷🇺 · T. Black🇺🇸 and 122 other authors

   We report on the measurement of the $\gamma p\to J/\psi p$ cross section from $E_{\gamma }=11.8$ GeV down to the threshold at $8.2$ GeV using a tagged photon beam with the GlueX experiment. We find the total cross section falls toward the threshold less steeply than expected from two-gluon exchange models. The differential cross section $d\sigma /dt$ has an exponential slope of $1.67\pm 0.39$ GeV${}^{-2}$ at $10.7$ GeV average energy. The LHCb pentaquark candidates $P_c^{+}$ can be produced in the $s$-channel of this reaction. We see no evidence for them and set model-dependent upper limits on their branching fractions $\mathcal{B}(P_c^{+}\to J/\psi p)$ and cross sections $\sigma (\gamma p\to P_c^{+})\times \mathcal{B}(P_c^{+}\to J/\psi p)$.

   nucl-exPRL(2019)·288 citations
3. 03*

   The proton charge radius extracted from the Initial State Radiation experiment at MAMI

   Miha Mihovilovič · Patrick Achenbach · Tobias Beranek · Jure Beričič · Jan C. Bernauer · Ralph Böhm · Damir Bosnar · Matteo Cardinali · Loup Correa · Luka Debenjak · Achim Denig · Michael O. Distler and 23 other authors

   We report on a comprehensive reinterpretation of the existing cross-section data for elastic electron-proton scattering obtained by the initial-state radiation technique, resulting in a significantly improved accuracy of the extracted proton charge radius. By refining the external energy corrections we have achieved an outstanding description of the radiative tail, essential for a detailed investigation of the proton finite-size effects on the measured cross-sections. This development, together with a novel framework for determining the radius, based on a regression analysis of the cross-sections employing a polynomial model for the form factor, led us to a new value for the charge radius, which is $(0.870\pm 0.014_{stat.}\pm 0.024_{sys.}\pm 0.003_{mod.})\mathrm{fm}$.

   nucl-exEPJA(2021)·60 citations
4. 04*

   Nuclear-matter distribution in the proton-rich nuclei ${}^7$Be and ${}^8$B from intermediate energy proton elastic scattering in inverse kinematics

   A.V. Dobrovolsky🇷🇺 · G.A. Korolev🇷🇺 · A.G. Inglessi🇷🇺 · G.D. Alkhazov🇷🇺 · G. Colò🇮🇹 · I. Dillmann🇨🇦 · P. Egelhof🇩🇪 · A. Estradé🇺🇸 · F. Farinon🇩🇪 · H. Geissel🇩🇪 · S.Ilieva🇧🇬 · Y. Ke🇩🇪 and 16 other authors

   Absolute differential cross sections for elastic $p^7$Be and $p^8$B small-angle scattering were measured in inverse kinematics at an energy of 0.7 GeV/u at GSI Darmstadt. The hydrogen-filled ionization chamber IKAR was used as an active target to detect the recoil protons. The projectile tracking and isotope identification were performed with multi-wire proportional chambers and scintillation detectors. The measured cross sections were analysed using the Glauber multiple-scattering theory. The root-mean-square (rms) nuclear matter radii $R_{\mathrm{m}}=2.42(4)$ fm for ${}^7$Be and $R_{\mathrm{m}}=2.58(6)$ fm for ${}^8$B were obtained. The radial density distribution deduced for ${}^8$B exhibits a proton halo structure with the rms halo radius $R_{\mathrm{h}}=4.24(25)$ fm. A comparison of the deduced experimental radii is displayed with existing experimental and theoretical data.

   nucl-exnucl-thNPA(2019)·22 citations
5. 05*

   Rescattering effects in antiproton-induced exclusive $J/\psi$ and ${\psi }^{\prime }$ production on the deuteron

   A.B. Larionov🇩🇪 · A. Gillitzer🇩🇪 · M. Strikman🇺🇸

   On the basis of the generalized eikonal approximation we study the exclusive reactions $\bar{p}d\to J/\psi n$ and $\bar{p}d\to {\psi }^{\prime }n$ in vicinity of the thresholds for charmonium production on a free proton target. It is shown that the rescattering of the incoming antiproton and outgoing charmonium on the spectator neutron leads to a depletion of the charmonium production at low- and to an enhancement at high transverse momenta. This is in qualitative agreement with previous studies of hard proton knockout in proton-deuteron collisions. We analyze different physical sources of uncertainty which may influence the extraction of the total charmonium-neutron cross section. The color transparency effect for the incoming $\bar{p}$ largely compensates the influence of charmonium rescattering both at low and high transverse momenta. Different choices of the deuteron wave function lead to significant uncertainties at high transverse momenta. As an outcome of the calculations of charmonium production, we also provide predictions on the production of open charm hadrons due to the dissociation of the charmonium on the neutron. It is shown that the open charm production cross section is proportional to the total charmonium-nucleon cross section and quite stable with respect to the variation of other parameters of the model. We thus suggest that open charm channels are most suited for future studies of charmonium-nucleon interactions at PANDA with a deuteron target.

   ↳ nucl-thhep-exhep-phnucl-exEPJA(2019)·3 citations
6. 06*

   Heavy ion physics at CMS and ATLAS: hard probes

   Gábor I. Veres (on behalf of the CMS and ATLAS Collaborations)🇭🇺

   Hard probes are indispensable tools to study the hot and dense quark-gluon matter created in ultra-relativistic heavy ion collisions. These probes are created in the collision itself with a small cross section, and they serve as indicators of various properties of the medium, such as temperature, viscosity, energy density, transport coefficients. Hard probes measured by the CMS and ATLAS experiments at the LHC include highly energetic jets and charged particles, quarkonium states, and electroweak gauge bosons. An overview of those recent experimental results will be given that represent the path towards high-precision measurements, even in the challenging, high-multiplicity environment created by colliding heavy ions.

   ↳ hep-exnucl-ex0 citations
7. 07*

   Ab initio limits of atomic nuclei

   S. R. Stroberg🇨🇦 · J. D. Holt🇨🇦 · A. Schwenk🇩🇪 · J. Simonis🇩🇪

   We predict the limits of existence of atomic nuclei, the proton and neutron drip lines, from the light through medium-mass regions. Starting from a chiral two- and three-nucleon interaction with good saturation properties, we use the valence-space in-medium similarity renormalization group to calculate ground-state and separation energies from helium to iron, nearly 700 isotopes in total. We use the available experimental data to quantify the theoretical uncertainties for our ab initio calculations towards the drip lines. Where the drip lines are known experimentally, our predictions are consistent within the estimated uncertainty. For the neutron-rich sodium to chromium isotopes, we provide predictions to be tested at rare-isotope beam facilities.

   ↳ nucl-thnucl-exPRL(2021)·267 citations
8. 08*

   A microscopic resolution of the chiral conundrum with crossing twin bands in Ag-106

   P. W. Zhao🇨🇳 · Y. K. Wang🇨🇳 · Q. B. Chen🇩🇪

   The nuclear chiral conundrum with crossing twin bands is investigated with three-dimensional tilted axis cranking covariant density functional theory in a fully self-consistent and microscopic way. The energy spectra and electromagnetic transition strengths for bands 1 and 2 in Ag-106 are well reproduced with two distinct configurations with two and four quasiparticles, respectively. For the four-quasiparticle configuration, a chiral vibrational band on top of band 2 is expected due to the soft Routhian curves. Therefore, it provides a microscopic and solid solution for the chiral conundrum in Ag-106. It also paves the way for understanding similar chiral structure in other nuclei in the future..

   ↳ nucl-thnucl-exPRC(2019)·22 citations
9. 09*

   Coherent elastic nuclear scattering of ${}^{51}$Cr neutrinos

   C. Bellenghi🇮🇹 · D. Chiesa🇮🇹 · L. Di Noto🇮🇹 · M. Pallavicini🇮🇹 · E. Previtali🇮🇹 · M. Vignati🇮🇹

   Searches for new physics in the coherent elastic neutrino-nucleus scattering require a precise knowledge of the neutrino flux and energy spectrum. In this paper we investigate the feasibility and the performances of an experiment based on a ${}^{51}$Cr source, whose neutrino spectrum is known and whose activity can be heat-monitored at few permil level. With a 5 MCi source placed at ~ 25 cm from the detector, under an exposure of two ${}^{51}$Cr half-lives (55.4 days), we evaluate 3900 (900) counts on a 2000 cm${}^3$ target of germanium (sapphire) featuring an energy threshold of 8 (20) eV. To further increase the exposure, multiple activations of the same source could be possible.

   ↳ physics.ins-dethep-exnucl-exEPJC(2019)·20 citations
10. 10*

    Results from proton-lead and fixed-target collisions at LHCb

    Daniele Marangotto (on behalf of the LHCb Collaboration)🇮🇹

    The latest results obtained by the LHCb collaboration from proton-lead and proton-gas fixed-target collisions are presented. Results related to charm and beauty flavour hadron and quarkonia production in proton-lead collisions, being clean probes for Cold Nuclear Matter effects, are compatible to predictions based on initial-state effects. Indications of significant final-state effects in excited ${\rm Y}(nS)$ resonances production are reported. The first cross-section measurement of $c\bar{c}$ and antiproton production in fixed-target proton-helium collisions at 100 GeV energy scale are also presented. More results will come from the latest Run 2 and future Run 3 data.

    ↳ hep-exnucl-exPublished as part of "Proceedings of the …·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.