1,228 research outputs found
Transversity studies with a polarized 3He target
A realistic study of the SiDIS process 3He(e , e
π)X in the Bjorken
limit is briefly reviewed, showing that the nuclear effects, present in the extraction
of the neutron information, are largely under theoretical control, within an ImpulseApproximation approach. In view of the forthcoming experimental data, we shortly
present a novel Poincar´e covariant description of the nuclear target, implementing a
Light-Front analysis at finite Q2, within the Bakamijan-Thomas construction of the
Poincar´e generators. Furthermore, as a by-product of the introduction of a LightFront spin-dependent spectral function for a J = 1/2 system, we straightforwardly
extend our analysis to the quark-quark correlator, obtaining three new exact relations between the six leading-twist Transverse-Momentum–Dependent distributions
Tunneling transport of unitary fermions across the superfluid transition
We investigate the transport of a Fermi gas with unitarity-limited interactions across the superfluid phase transition, probing its response to a direct current (dc) drive through a tunnel junction. As the superfluid critical temperature is crossed from below, we observe the evolution from a highly nonlinear to an Ohmic conduction characteristic, associated with the critical breakdown of the Josephson dc current induced by pair condensate depletion. Moreover, we reveal a large and dominant anomalous contribution to resistive currents, which reaches its maximum at the lowest attained temperature, fostered by the tunnel coupling between the condensate and phononic Bogoliubov-Anderson excitations. Increasing the temperature, while the zeroing of supercurrents marks the transition to the normal phase, the conductance drops considerably but remains much larger than that of a normal, uncorrelated Fermi gas tunneling through the same junction. We attribute such enhanced transport to incoherent tunneling of sound modes, which remain weakly damped in the collisional hydrodynamic fluid of unpaired fermions at unitarity
Erratum to: A study of vorticity formation in high energy nuclear collisions
Due to an oversight of ours in proofreading and a communication problem with the publisher, the figures published in F. Becattini et al. Eur. Phys. J. C (2015) 75: 406 were not correct. This Erratum contains the correct figures as in arXiv 1501.04468v2, submitted on March 12 2015, and the post-publication version arXiv 1501.04468v3, submitted on August 17 2015
Relativistic viscous hydrodynamics for heavy-ion collisions with ECHO-QGP
We present ECHO-QGP, a numerical code for -dimensional relativistic
viscous hydrodynamics designed for the modeling of the space-time evolution of
the matter created in high energy nuclear collisions. The code has been built
on top of the \emph{Eulerian Conservative High-Order} astrophysical code for
general relativistic magneto-hydrodynamics [\emph{Del Zanna et al., Astron.
Astrophys. 473, 11, 2007}] and here it has been upgraded to handle the physics
of the Quark-Gluon Plasma. ECHO-QGP features second-order treatment of causal
relativistic viscosity effects in both Minkowskian or Bjorken coordinates;
partial or complete chemical equilibrium of hadronic species before kinetic
freeze-out; initial conditions based on the optical Glauber model, including a
Monte-Carlo routine for event-by-event fluctuating initial conditions; a
freeze-out procedure based on the Cooper-Frye prescription. The code is
extensively validated against several test problems and results always appear
accurate, as guaranteed by the combination of the conservative
(shock-capturing) approach and the high-order methods employed. ECHO-QGP can be
extended to include evolution of the electromagnetic fields coupled to the
plasma.Comment: 25 pages, two column, Final version: accepted for publication in
European Physical Journal
Distorted spin-dependent spectral function of an A=3 nucleus and semi-inclusive deep inelastic scattering processes
The distorted spin-dependent spectral function of a nucleon inside an A = 3 nucleus is introduced as a
novel tool for investigating the polarized electron scattering off polarized 3He in the semi-inclusive DIS regime
(SiDIS), going beyond the standard plane-wave impulse approximation. This distribution function is applied 3⃗ ′2
to the study of the spectator SiDIS, He(e⃗,e H)X, to properly take into account the final-state interaction
between the hadronizing quark and the detected deuteron, with the final goal of a more reliable extraction of the
polarized parton distribution g1(x) inside a bound proton. Our analysis allows one to single out two well-defined
kinematical regions where the experimental asymmetries could yield very interesting information: the region
where the final-state effects can be minimized, and therefore the direct access to the parton distributions in the
proton is feasible, and the one where the final-state interaction dominates, and the spectator SiDIS reactions can
elucidate the mechanism of the quark hadronization itself. The perspectives of extending our approach (i) to
the mirror nucleus, 3H, for achieving a less model-dependent flavor decomposition and (ii) to the asymmetries 3⃗′
measured in the standard SiDIS reactions, e⃗ + He → e + h + X, with h a detected fast hadron, with the aim of extracting the neutron transversity, are discussed
Hypothermic Oxygenated New Machine Perfusion System in Liver and Kidney Transplantation of Extended Criteria Donors:First Italian Clinical Trial
With the aim to explore innovative tools for organ preservation, especially in marginal organs, we hereby describe a clinical trial of ex-vivo hypothermic oxygenated perfusion (HOPE) in the field of liver (LT) and kidney transplantation (KT) from Extended Criteria Donors (ECD) after brain death. A matched-case analysis of donor and recipient variables was developed: 10 HOPE-ECD livers and kidneys (HOPE-L and HOPE-K) were matched 1:3 with livers and kidneys preserved with static cold storage (SCS-L and SCS-K). HOPE and SCS groups resulted with similar basal characteristics, both for recipients and donors. Cumulative liver and kidney graft dysfunction were 10% (HOPE L-K) vs. 31.7%, in SCS group (p = 0.05). Primary non-function was 3.3% for SCS-L vs. 0% for HOPE-L. No primary non-function was reported in HOPE-K and SCS-K. Median peak aspartate aminotransferase within 7-days post-LT was significantly higher in SCS-L when compared to HOPE-L (637 vs.344 U/L, p = 0.007). Graft survival at 1-year post-transplant was 93.3% for SCS-L vs. 100% of HOPE-L and 90% for SCS-K vs. 100% of HOPE-K. Clinical outcomes support our hypothesis of machine perfusion being a safe and effective system to reduce ischemic preservation injuries in KT and in LT
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