Thu·Nov 9, 2017Thursday·November 9, 2017

1. 01*

   First results on the measurements of the proton beam polarization at internal target at Nuclotron

   V.P.Ladygin🇷🇺 · Yu.V.Gurchin🇷🇺 · A.Yu.Isupov🇷🇺 · M.Janek🇸🇰 · A.N.Khrenov🇷🇺 · P.K.Kurilkin🇷🇺 · A.N.Livanov🇷🇺 · S.M.Piyadin🇷🇺 · S.G.Reznikov🇷🇺 · Ya.T.Skhomenko🇷🇺 · A.A.Terekhin🇷🇺 · A.V.Tishevsky🇷🇺 and 17 other authors

   The spin program at NICA using SPD and MPD requires high intensity polarized proton beam with high value of the beam polarization. First results on the measurements of the proton beam polarization performed at internal target at Nuclotron are reported. The polarization of the proton beam provided by new source of polarized ions has been measured at 500 MeV using quasielastic proton-proton scattering and DSS setup at internal target. The obtained value of the vertical polarization of ~35 % is consistent with the calculations taking into account the current magnetic optics of the Nuclotron injection line.

   ↳ physics.ins-detnucl-exJ.Phys.Conf.Ser.(2017)·9 citations
2. 02*

   Exclusive vector meson photoproduction with a leading baryon in photon - hadron interactions at hadronic colliders

   F. Carvalho🇧🇷 · V.P. Goncalves🇧🇷 · F.S. Navarra🇧🇷 · D. Spiering🇧🇷

   Exclusive vector meson photoproduction associated with a leading baryon ($B=n,{\Delta }^{+},{\Delta }^0$) in $pp$ and $pA$ collisions at RHIC and LHC energies is investigated using the color dipole formalism and taking into account nonlinear effects in the QCD dynamics. In particular, we compute the cross sections for $\rho$, $\varphi$ and $J/\Psi$ production together with a $\Delta$ and compare the predictions with those obtained for a leading neutron. Our results show that the $V+\Delta$ cross section is almost 30 % of the $V+n$ one. Our results also show that a future experimental analysis of these processes is, in principle, feasible and can be useful to study leading particle production.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2018)·6 citations
3. 03*

   Probing the time structure of the quark-gluon plasma with top quarks

   Liliana Apolinário🇵🇹 · José Guilherme Milhano🇵🇹 · Gavin P. Salam🇨🇭 · Carlos A. Salgado🇪🇸

   The tiny droplets of Quark Gluon Plasma (QGP) created in high-energy nuclear collisions experience fast expansion and cooling with a lifetime of a few $\text{fm}/c$. Despite the information provided by probes such as jet quenching and quarkonium suppression, and the excellent description by hydrodynamical models, direct access to the time evolution of the system remains elusive. We point out that the study of hadronically-decaying $W$ bosons, notably in events with a top-antitop quark pair, can provide key novel insight, into the time structure of the QGP. This is because of a unique feature, namely a time delay between the moment of the collision and that when the $W$-boson decay products start interacting with the medium. Furthermore, the length of the time delay can be constrained by selecting specific reconstructed top-quark momenta.

   ↳ hep-phhep-exnucl-exnucl-thPRL(2018)·90 citations
4. 04*

   Directed flow in heavy-ion collisions and its implications for astrophysics

   Yuri B. Ivanov🇷🇺

   Analysis of directed flow ($v_1$) of protons, antiprotons and pions in heavy-ion collisions is performed in the range of collision energies $\sqrt{s_{NN}}$ = 2.7--39 GeV. Simulations have been done within a three-fluid model employing a purely hadronic equation of state (EoS) and two versions of the EoS with deconfinement transitions: a first-order phase transition and a smooth crossover transition. The crossover EoS is unambiguously preferable for the description of experimental data at lower collision energies $\sqrt{s_{NN}}\le$ 20 GeV. However, at higher collision energies $\sqrt{s_{NN}}\ge$ 20 GeV the purely hadronic EoS again becomes advantageous. This indicates that the deconfinement EoS in the quark-gluon sector should be stiffer at high baryon densities than those used in the calculation. The latter finding is in agreement with that discussed in astrophysics in connection with existence of hybrid stars with masses up to about two solar masses.

   ↳ nucl-thastro-ph.HEhep-phnucl-exUniverse(2017)·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.