Search results for "visti"

Momentum anisotropy effects for quarkonium in a weakly coupled quark-gluon plasma below the melting temperature

2017

In the early stages of heavy-ion collisions, the hot QCD matter expands more longitudinally than transversely. This imbalance causes the system to become rapidly colder in the longitudinal direction and a local momentum anisotropy appears. In this paper, we study the heavy-quarkonium spectrum in the presence of a small plasma anisotropy. We work in the framework of pNRQCD at finite temperature. We inspect arrangements of non-relativistic and thermal scales complementary to those considered in the literature. In particular, we consider temperatures larger and Debye masses smaller than the binding energy, which is a temperature range relevant for presently running LHC experiments. In this set…

Low-momentum direct-photon measurement in Cu + Cu collisions at √sNN = 200 GeV

2018

We measured direct photons for pT < 5 GeV/c in minimum bias and 0%–40% most-central events at midrapidity for Cu+Cu collisions at √sNN = 200 GeV. The e+e− contribution from quasireal direct virtual photons has been determined as an excess over the known hadronic contributions in the e+e− mass distribution. A clear enhancement of photons over the binary scaled p+p fit is observed for pT < 4 GeV/c in Cu+Cu data. The pT spectra are consistent with the Au+Au data covering a similar number of participants. The inverse slopes of the exponential fits to the excess after subtraction of the p+p baseline are 285 ± 53(stat) ± 57(syst) MeV/c and 333 ± 72(stat) ± 45(syst) MeV/c for minimum bias and 0%–4…

Event-by-event fluctuations in a perturbative QCD + saturation + hydrodynamics model: Determining QCD matter shear viscosity in ultrarelativistic hea…

2016

We introduce an event-by-event perturbative-QCD + saturation + hydro (“EKRT”) framework for ultrarelativistic heavy-ion collisions, where we compute the produced fluctuating QCD-matter energy densities from next-to-leading-order perturbative QCD using a saturation conjecture to control soft-particle production and describe the space-time evolution of the QCD matter with dissipative fluid dynamics, event by event. We perform a simultaneous comparison of the centrality dependence of hadronic multiplicities, transverse momentum spectra, and flow coefficients of the azimuth-angle asymmetries against the LHC and RHIC measurements. We compare also the computed event-by-event probability distribut…

Babij Jar: lo sterminio taciuto e l’arte dell’eufemismo

2020

Confrontando le poesie dedicate al massacro di Babij Jar (lo sterminio metodico di tutta la popolazione ebraica rimasta a Kiev dopo la conquista nazista) da Il’ja Erenburg ed Evgenij Evtušenko dovremmo con ogni probabilità considerare superiore quella del primo. La sua qualità poetica deriva in gran parte dall’uso dell’allusione, del non detto, che apre spazi semantici superiori; questa caratteristica deriva però probabilmente da un caso di necessità: Erenburg, che scriveva nel 1945, cercava evidentemente una strada per far penetrare alla stampa una commemorazione delle vittime di Babij Jar in un periodo in cui, in Unione Sovietica, era impossibile farlo in modo più esplicito – nella prima …

Spanish Relativity Meeting (ERE 2014): almost 100 years after Einstein's revolution

2015

This volume presents the proceedings of the international scientific conference ''Spanish Relativity Meeting (ERE 2014): almost 100 years after Einstein's revolution''. The conference was devoted to discussing the current state-of-the-art of a wide variety of topics of research in the fields of Gravitation and General Relativity in the ''pre-centennial'' year of General Relativity. The name of the conference was chosen to highlight the importance of the upcoming one hundredth anniversary of Einstein's theory of General Relativity, officially established by the Internal Society on General Relativity and Gravitation in November 25th, 2015. In particular, the conference was organized along thr…

Direct perturbation theory in terms of energy derivatives: scalar-relativistic treatment up to sixth order.

2011

A formulation of sixth-order direct perturbation theory (DPT) to treat relativistic effects in quantum-chemical calculations is presented in the framework of derivative theory. Detailed expressions for DPT6 are given at the Hartree-Fock level in terms of the third derivative of the energy with respect to the relativistic perturbation parameter defined as λ(rel)=c(-2). They were implemented for the computation of scalar-relativistic energy corrections. The convergence of the scalar-relativistic DPT expansion is studied for energies and first-order properties such as dipole moment and electric-field gradient within the series of the hydrogen halides (HX, X = F, Cl, Br, I, and At). Comparison …

Laser spectroscopy measurement of the 2s-hyperfine splitting in lithium-like bismuth

2017

We have recently reported on the first direct measurement of the $2s$ hyperfine transition in lithium-like bismuth (209Bi80+) at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany. Combined with a new measurement of the $1s$ hyperfine splitting (HFS) in hydrogen-like (209Bi82+) the so-called specific difference ${\rm{\Delta }}^{\prime} E=-61.37(36)$ meV could be determined and was found to be in good agreement with its prediction from strong-field bound-state quantum electrodynamics. Here we report on additional investigations performed to estimate systematic uncertainties of these results and on details of the experimental setup. We show that the dominating uncertainty a…

Microwave, High-Resolution Infrared, and Quantum Chemical Investigations of CHBrF2: Ground and v4 = 1 States

2011

A combined microwave, infrared, and computational investigation of CHBrF(2) is reported. For the vibrational ground state, measurements in the millimeter- and sub-millimeter-wave regions for CH(79)BrF(2) and CH(81)BrF(2) provided rotational and centrifugal-distortion constants up to the sextic terms as well as the hyperfine parameters (quadrupole-coupling and spin-rotation interaction constants) of the bromine nucleus. The determination of the latter was made possible by recording of spectra at sub-Doppler resolution, achieved by means of the Lamb-dip technique, and supporting the spectra analysis by high-level quantum chemical calculations at the coupled-cluster level. In this context, the…

Svenska språkets värde och funktioner språkhierarkier i flerspråkig nätkontext

2009

"Non solo lei, Stirlitz, soffre di nostalgia": La nostalgia dell'est dell'agente infiltrato e la nostalgia dell'ovest del lettore nel romanzo di spio…

2016

In Iulian Semenov's 1969 Seventteen Moments of Spring the hero's (a Soviet undercover agent in Nazi Germany) nostalgia for the motherland is so strongly underscored thtat it becomes ridiculous. Such a stress on nostalgia was, as it appears, necessary in order to compensate the envy the reader would fatally feel for the comfort of his "European" life among the enemy. The double agent became, in fact, an allegory of the "double life" of the soviet citizen in the Seventies, regardless of the fact that the novel was sponsored by the KGB. Or was this an intentional projection of Iurii Andropov's self-constructed image?