Tue·Jul 3, 2018Tuesday·July 3, 2018

1. 01*

   Phenomenological models of two-particle correlation distributions on transverse momentum in relativistic heavy-ion collisions

   R. L. Ray🇺🇸 · A. Jentsch🇺🇸

   Two-particle, pair-number correlation distributions on two-dimensional transverse momentum ($p_{t1},p_{t2}$) constructed from the particle production in relativistic heavy-ion collisions allow access to dynamical processes in these systems beyond what can be studied with angular correlations alone. Only a few measurements of this type have been reported in the literature and phenomenological models, which facilitate physical interpretation of the correlation structures, are non-existent. On-going effort at the Relativistic Heavy-Ion Collider (RHIC) will provide a significant volume of these correlation measurements in the future. In anticipation of these new data two phenomenological models are developed which describe two-dimensional 2D correlation distributions on transverse momentum. One model is based on a collision event-by-event fluctuating blast wave. The other is based on event-by-event fluctuations in fragmenting color-flux tubes and in jets. Both models are shown to be capable of accurately describing the measured single-particle $p_t$ distributions for minimum-bias Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=200$~GeV. Both models are then applied to preliminary, charged-particle correlation measurements on 2D transverse momentum. The capabilities of the two models for describing the overall structure of these correlations, the stability of the fitting results with respect to collision centrality, and the resulting trends of the dynamical fluctuations are evaluated. In general, both phenomenological models are capable of qualitatively describing the major correlation structures on transverse momentum and can be used to establish the required magnitudes and centrality trends of the fluctuations. Both models will be useful for interpreting the forthcoming correlation data from the RHIC.

   nucl-exPRC(2019)·8 citations
2. 02*

   Dipion photoproduction and the $Q^2$ evolution of the shape of the gold nucleus

   Spencer R. Klein (for the STAR Collabortion)🇺🇸

   Coherent photoproduction of vector mesons is sensitive to the shape of the target nucleus, as probed at four-momentum scale $Q^2\propto (M_V/2{)}^2$. Previously STAR presented a high-statistics measurement of $d{\sigma }_c/dt$ for coherent ${\pi }^{+}{\pi }^{-}$ photoproduction in ultra-peripheral gold-gold collisions, and made a two-dimensional Fourier-Bessel (Hanckel) transformation to give the transverse distribution of interactions in the nucleus. Here, we study how $d{\sigma }_c/dt$ evolves with $Q^2$. We divide the ${\pi }^{+}{\pi }^{-}$ signal into three different mass ($Q^2$) bins to measure how $d{\sigma }_c/dt$ evolves with dipion mass. Furthermore, we find that the depth of the first diffractive minimum varies with pair mass. We perform a two-dimensional Fourier-Bessel transform to see how the effective transverse distribution of the interactions changes with decreasing pair mass. In the lowest mass bin, the nuclear profile is broader, which is consistent with expectations from saturation models.

   nucl-exhep-phPoS(2018)·9 citations
3. 03*

   Wide acceptance measurement of the K${}^{-}$/K${}^{+}$ ratio from Ni+Ni collisions at 1.91A GeV

   K. Piasecki🇵🇱 · N. Herrmann🇩🇪 · R. Averbeck🇩🇪 · A. Andronic🇩🇪 · V. Barret🇫🇷 · Z. Basrak🇭🇷 · N. Bastid🇫🇷 · M.L. Benabderrahmane🇩🇪 · M. Berger🇩🇪 · P. Buehler🇦🇹 · M. Cargnelli🇦🇹 · R. Čaplar🇭🇷 and 61 other authors

   The FOPI Collaboration at the GSI SIS-18 synchrotron measured charged kaons from central and semi-central collisions of Ni+Ni at a beam energy of 1.91A GeV. We present the distribution of the K${}^{-}$\K${}^{+}$ ratio on the energy vs polar angle plane in the nucleon-nucleon center-of-mass frame, with and without subtraction of the contribution of $\varphi$(1020) meson decays to the K${}^{-}$ yield. The acceptance of the current experiment is substantially wider compared to the previous measurement of the same colliding system. The ratio of K${}^{-}$ to K${}^{+}$ energy spectra is expected to be sensitive to the in-medium modifications of basic kaon properties like mass. Recent results obtained by the HADES Collaboration at 1.23A and 1.76A GeV indicate that after inclusion of the $\varphi$ meson decay contribution to the K${}^{-}$ production no difference between the slopes of the K${}^{-}$ and K${}^{+}$ energy spectra is observed within uncertainties. For our data a linear fit to this ratio obtained after subtraction of the $\varphi$ meson contribution still shows a decrease with kinetic energy, although a constant value cannot be rejected. The contribution of $\Lambda (1520)\to p{\text{K}}^{-}$ decays estimated from fitting the thermal model to the experimental yields appears to be another factor of moderate relevance.

   nucl-exPRC(2019)·7 citations
4. 04*

   Search of the neutrino-less double beta decay of ${}^{82}$Se into the excited states of ${}^{82}$Kr with CUPID-0

   O. Azzolini🇮🇹 · M.T. Barrera🇮🇹 · J.W. Beeman🇺🇸 · F. Bellini🇮🇹 · M. Beretta🇮🇹 · M. Biassoni🇮🇹 · E. Bossio🇮🇹 · C. Brofferio🇮🇹 · C. Bucci🇮🇹 · L. Canonica🇮🇹 · S. Capelli🇮🇹 · L. Cardani🇮🇹 and 38 other authors

   The CUPID0 experiment searches for double beta decay using cryogenic calorimeters with double (heat and light) read-out. The detector, consisting of 24 ZnSe crystals 95$\%$ enriched in ${}^{82}$Se and 2 natural ZnSe crystals, started data-taking in 2017 at Laboratori Nazionali del Gran Sasso. We present the search for the neutrino-less double beta decay of ${}^{82}$Se into the 0${}_1^{+}$, 2${}_1^{+}$ and 2${}_2^{+}$ excited states of ${}^{82}$Kr with an exposure of 5.74 kg$\cdot$yr (2.24$\times$10${}^{25}$ emitters$\cdot$yr). We found no evidence of the decays and set the most stringent limits on the widths of these processes: $\Gamma$(${}^{82}$Se ${\to }^{82}$Kr${}_{0_1^{+}}$)$<$8.55$\times$10${}^{-24}$ yr${}^{-1}$, $\Gamma$(${}^{82}$Se ${\to }^{82}$Kr${}_{2_1^{+}}$)$<6.25\times 10^{-24}$ yr${}^{-1}$, $\Gamma$(${}^{82}$Se ${\to }^{82}$Kr${}_{2_2^{+}}$)$<$8.25$\times$10${}^{-24}$ yr${}^{-1}$ (90$\%$ credible interval

   nucl-exphysics.ins-detEPJC(2018)·33 citations
5. 05*

   Proceedings of "Open heavy flavour production in heavy-ion collisions with ALICE, The 34th Winter Workshop on Nuclear Dynamics", 25-31 March 2018

   Martin Völkl (for the ALICE Collaboration)🇩🇪

   Heavy-flavour measurements give an important contribution to the understanding of the Quark-Gluon Plasma (QGP) produced in heavy-ion collisions. Heavy quarks are effective probes for the QGP and understanding their interaction with the medium can give insights into its transport properties. The ALICE Collaboration investigates heavy-flavour production by measuring leptons from heavy-flavour decays and by reconstructing hadronic decays of D mesons and charmed baryons. In this proceeding, recent results from ALICE as well as the direction of future heavy-flavour measurements are discussed.

   nucl-exJ.Phys.Conf.Ser.(2018)·0 citations
6. 06*

   Nuclear beta decays and CKM unitarity

   J.C. Hardy🇺🇸 · I.S. Towner🇺🇸

   Nuclear beta decays between (J^pi,T) = (0^+,1) analog states yield the best value for the Vud element of the Cabibbo-Kobayashi-Maskawa matrix. Current world data establish the corrected Ft values of 14 separate superallowed transitions to a precision of order 0.1% or better. The validity of the small theoretical correction terms is confirmed by excellent consistency among the 14 Ft values and by recent measurements that compare pairs of mirror superallowed transitions. With consistency established, the results now yield |Vud| = 0.97420(21). This value is consistent with the considerably less precise results obtained from beta decays of the neutron, the pion and T=1/2 mirror nuclei, which are hampered by experimental challenges.

   nucl-exhep-phnucl-th25 citations
7. 07*

   Exotics at Our Home

   Nikolay Achasov🇷🇺

   I. Light Scalars as Four-quark States II. Isotensor Tensor Tensor E(1500-1600) State III. X(3872) State as Charmonium \chi_{c1}(2P) IV. Two-gluon Annihilation of Charmonium \chi_{c2}(2P) There are considered problems of the exotic states, in which the author with his collaborators has made clear physical predictions, considerable part of wich is supported by experement already

   ↳ hep-phhep-exnucl-exEPJ Web Conf.(2018)·1 citation
8. 08*

   Jost-matrix analysis of the resonance 5He*(3/2+) near the dt-threshold

   S.A. Rakityansky🇿🇦 · S.N. Ershov🇷🇺

   Experimental data on the n-alpha and dt collisions in the quantum state J^pi=3/2+ near the dt-threshold are fitted using the semi-analytic multi-channel Jost matrix with proper analytic structure and some adjustable parameters. Then the spectral points are sought as zeros of the Jost matrix determinant (which correspond to the S-matrix poles) at complex energies. The correct analytic structure makes it possible to calculate the fitted Jost matrix on any sheet of the Riemann surface whose topology involves not only the square-root but also the logarithmic branching caused by the Coulomb interaction. Within a distance of 100,keV above the dt-threshold, three 3/2+ resonances are found on the non-physical sheet of the Riemann surface. Several S-matrix (shadow) poles on the other sheets of this surface are located as well.

   ↳ nucl-thnucl-exIJMPE(2019)·7 citations
9. 09*

   Advanced Methods for the Optical Quality Assurance of Silicon Sensors

   E. Lavrik🇩🇪 · I. Panasenko🇩🇪 · H.R. Schmidt🇩🇪

   We describe a setup for optical quality assurance of silicon microstrip sensors. Pattern recognition algorithms were developed to analyze microscopic scans of the sensors for defects. It is shown that the software has a recognition and classification rate of $>$~90\% for defects like scratches, shorts, broken metal lines etc. We have demonstrated that advanced image processing based on neural network techniques is able to further improve the recognition and defect classification rate.

   ↳ physics.ins-detcs.LGhep-exnucl-exNucl.Instrum.Meth.A(2019)·4 citations
10. 10*

    Transversity parton distribution functions from lattice QCD

    Constantia Alexandrou🇨🇾 · Krzysztof Cichy🇵🇱 · Martha Constantinou🇺🇸 · Karl Jansen🇩🇪 · Aurora Scapellato🇨🇾 · Fernanda Steffens🇩🇪

    We present the first direct calculation of the transversity parton distribution function within the nucleon from lattice QCD. The calculation is performed using simulations with the light quark mass fixed to its physical value and at one value of the lattice spacing. Novel elements of the calculations are non-perturbative renormalization and extraction of a formula for the matching to light-cone PDFs. Final results are presented in the $\overline{\mathrm{MS}}$ scheme at a scale of $\sqrt{2}$ GeV.

    ↳ hep-lathep-exhep-phnucl-ex+1PRD(2018)·163 citations
11. 11*

    Microscopic predictions of the nuclear matter liquid-gas phase transition

    Arianna Carbone🇩🇪 · Artur Polls🇪🇸 · Arnau Rios🇬🇧

    We present first-principle predictions for the liquid-gas phase transition in symmetric nuclear matter employing both two- and three-nucleon chiral interactions. Our discussion focuses on the sources of systematic errors in microscopic quantum many body predictions. On the one hand, we test uncertainties of our results arising from changes in the construction of chiral Hamiltonians. We use five different chiral forces with consistently derived three-nucleon interactions. On the other hand, we compare the ladder resummation in the self-consistent Green's functions approach to finite temperature Brueckner--Hartree--Fock calculations. We find that systematics due to Hamiltonians dominate over many-body uncertainties. Based on this wide pool of calculations, we estimate that the critical temperature is $T_c=16\pm 2$ MeV, in reasonable agreement with experimental results. We also find that there is a strong correlation between the critical temperature and the saturation energy in microscopic many-body simulations.

    ↳ nucl-thnucl-exPRC(2018)·45 citations
12. 12*

    A Fixed-Target Programme at the LHC: Physics Case and Projected Performances for Heavy-Ion, Hadron, Spin and Astroparticle Studies

    C. Hadjidakis🇫🇷 · D. Kikoła🇵🇱 · J.P. Lansberg🇫🇷 · L. Massacrier🇫🇷 · M.G. Echevarria🇮🇹 · A. Kusina🇵🇱 · I. Schienbein🇫🇷 · J. Seixas🇵🇹 · H.S. Shao🇫🇷 · A. Signori🇺🇸 · B. Trzeciak🇳🇱 · S.J. Brodsky🇺🇸 and 20 other authors

    We review the context, the motivations and the expected performances of a comprehensive and ambitious fixed-target program using the multi-TeV proton and ion LHC beams. We also provide a detailed account of the different possible technical implementations ranging from an internal wire target to a full dedicated beam line extracted with a bent crystal. The possibilities offered by the use of the ALICE and LHCb detectors in the fixed-target mode are also reviewed.

    ↳ hep-exhep-phnucl-exnucl-thPhys.Rept.(2021)·130 citations
13. 13*

    The MPGD-Based Photon Detectors for the upgrade of COMPASS RICH-1 and beyond

    J. Agarwala · M. Alexeev · C.D.R. Azevedo · F. Bradamante · A. Bressan · M. Buchele · M. Chiosso · C. Chatterjee · P. Ciliberti · S. Dalla Torre · S. Dasgupta · O. Denisov and 17 other authors

    After pioneering gaseous detectors of single photon for RICH applications using CsI solid state photocathodes in MWPCs within the RD26 collaboration and by the constructions for the RICH detector of the COMPASS experiment at CERN SPS, in 2016 we have upgraded COMPASS RICH by novel gaseous photon detectors based on MPGD technology. Four novel photon detectors, covering a total active area of 1.5~m${}^2$, have been installed in order to cope with the challenging efficiency and stability requirements of the COMPASS physics programme. These detectors are the first application in an experiment of MPGD-based single photon detectors. All aspects of the upgrade are presented, including engineering, mass production, quality assessment and performance. Perspectives for further developments in the field of gaseous single photon detectors are also presented.

    ↳ physics.ins-dethep-exnucl-exNucl.Instrum.Meth.A(2019)·24 citations
14. 14*

    Systematics of azimuthal anisotropy harmonics in proton-nucleus collisions at the LHC from the Color Glass Condensate

    Mark Mace🇺🇸 · Vladimir V. Skokov🇺🇸 · Prithwish Tribedy🇺🇸 · Raju Venugopalan🇺🇸

    Simple power counting arguments in the dilute-dense framework of the Color Glass Condensate (CGC) Effective Field Theory predict that even and odd azimuthal anisotropy harmonics of two-particle correlations in proton-nucleus collisions at the LHC will respectively satisfy v^2_{2n} ~ N_{ch}^0 and v^2_{2n+1} ~ N_{ch}, where N_{ch} denotes the number of charged particles. We show that these expectations are borne out qualitatively, and even quantitatively, within systematic uncertainties, for v_2 and v_4 in comparisons with data from the ATLAS collaboration. We also observe that ATLAS data for the v_3 azimuthal harmonic are in excellent agreement with our qualitative expectation; quantitative comparisons are numerically challenging at present. The lessons from this study fully complement those gained by the recent comparison of the CGC dilute-dense framework [arXiv:1805.09342] to data from the PHENIX collaboration on small system collisions at RHIC.

    ↳ hep-phnucl-exnucl-thPLB(2019)·65 citations
15. 15*

    Connecting the nuclear EoS to the interplay between fusion and quasifission processes in low-energy nuclear reactions

    H. Zheng🇨🇳 · S. Burrello🇮🇹 · M. Colonna🇮🇹 · D. Lacroix🇫🇷 · G. Scamps🇯🇵

    Within the Time Dependent Hartree Fock (TDHF) approach, we investigate the impact of several ingredients of the nuclear effective interaction, such as incompressibility, symmetry energy, effective mass, derivative of the Lane potential and surface terms on the exit channel (fusion vs quasifission) observed in the reaction ${}^{238}$U+${}^{40}$Ca, close to the Coulomb barrier. Our results show that all the ingredients listed above contribute to the competition between fusion and quasifission processes, however the leading role in determining the outcome of the reaction is played by incompressibility, symmetry energy and the isoscalar coefficient of the surface term. This study unravels the complexity of the fusion and quasifission reaction dynamics and helps to understand the microscopic processes responsible for the final outcome of low energy heavy ion collisions in terms of relevant features of the nuclear effective interaction and associated equation of state (EoS).

    ↳ nucl-thnucl-exPRC(2018)·44 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.