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Nuclear Theory·nucl-th

Wednesday·November 25, 2015

6 papers—3 primary·3 cross-listed

All6Primary3Cross-lists3
  1. 01

    Microscopic Theory of Nuclear Fission: A Review

    N. Schunck · L. M. Robledo

    This article reviews how nuclear fission is described within nuclear density functional theory. In spontaneous fission, half-lives are the main observables and quantum tunnelling the essential concept, while in induced fission the focus is on fragment properties and explicitly time-dependent approaches are needed. The cornerstone of the current microscopic theory of fission is the energy density functional formalism. Its basic tenets, including tools such as the HFB theory, effective two-body effective nuclear potentials, finite-temperature extensions and beyond mean-field corrections, are presented succinctly. The EDF approach is often combined with the hypothesis that the time-scale of the large amplitude collective motion driving the system to fission is slow compared to typical time-scales of nucleons inside the nucleus. In practice, this hypothesis of adiabaticity is implemented by introducing (a few) collective variables and mapping out the many-body Schrödinger equation into a collective Schrödinger-like equation for the nuclear wave-packet. Scission configurations indicate where the split occurs. This collective Schrödinger equation depends on an inertia tensor that includes the response of the system to small changes in the collective variables and also plays a special role in the determination of spontaneous fission half-lives. A trademark of the microscopic theory of fission is the tremendous amount of computing needed for practical applications. In particular, the successful implementation of the theories presented in this article requires a very precise numerical resolution of the HFB equations for large values of the collective variables. Finally, a selection of the most recent and representative results obtained for both spontaneous and induced fission is presented with the goal of emphasizing the coherence of the microscopic approaches employed.

    nucl-thRept.Prog.Phys.(2016)·263 citations
  2. 02

    Alpha Decay Width of Po from a quartetting wave function approach

    Chang Xu🇨🇳 · Zhongzhou Ren🇨🇳 · G. Röpke🇩🇪 · P. Schuck🇫🇷 · Y. Funaki🇯🇵 · H. Horiuchi🇯🇵 · A. Tohsaki🇯🇵 · T. Yamada🇯🇵 · Bo Zhou🇯🇵

    A microscopic calculation of -cluster preformation probability and decay width in the typical emitter Po is presented. Results are obtained by improving a recent approach to describe preformation in Po [Phys. Rev. C 90, 034304 (2014)] implementing four-nucleon correlations (quartetting). Using the actually measured density distribution of the Pb core, the calculated alpha decay width of Po agrees fairly well with the measured one.

    nucl-thPRC(2016)·94 citations
  3. 03

    Recent developments in the theory of electromagnetic probes in relativistic heavy-ion collisions

    Chun Shen (McGill U.)🇨🇦

    The theoretical developments in the study of electromagnetic radiation in relativistic heavy-ion collisions are reviewed. The recent progress in the rates for photon and lepton pair production is discussed. Together with the improvements in the hydrodynamic descriptions of the bulk medium, the combined effort is discussed to resolve the "direct photon flow puzzle" in the RHIC and the LHC experiments. Further prediction of the direct photon production in high multiplicity proton-nucleus collisions at the LHC energy can serve as a signature of the quark gluon plasma formation in these small systems. Phenomenological study of dilepton production at finite net baryon density is highlighted at the collision energies available for the RHIC beam energy scan program.

    nucl-thhep-phnucl-exNucl.Part.Phys.Proc.(2016)·14 citations
  4. 04

    Diffractive Dijet Production in Deep Inelastic Scattering and Photon-Hadron Collisions in the Color Glass Condensate

    Tolga Altinoluk🇪🇸 · Néstor Armesto🇪🇸 · Guillaume Beuf🇮🇹 · Amir H. Rezaeian🇨🇱

    We study exclusive dijet production in coherent diffractive processes in deep inelastic scattering and real (and virtual) photon-hadron (-h) collisions in the Color Glass Condensate formalism at leading order. We show that the diffractive dijet cross section is sensitive to the color-dipole orientation in the transverse plane, and is a good probe of possible correlations between the -dipole transverse separation vector \r and the dipole impact parameter . We also investigate the diffractive dijet azimuthal angle correlations and -distributions in -h collisions and show that they are sensitive to gluon saturation effects in the small- region. In particular, we show that the -distribution of diffractive dijet photo-production off a proton target exhibits a dip-type structure in the saturation region. This effect is similar to diffractive vector meson production. Besides, at variance with the inclusive case, the effect of saturation leads to stronger azimuthal correlations between the jets.

    ↳ hep-phhep-exnucl-thPLB(2016)·105 citations
  5. 05

    On the Evolution of Jet Energy and Opening Angle in Strongly Coupled Plasma

    Paul M. Chesler🇺🇸 · Krishna Rajagopal🇺🇸

    We calculate how the energy and the opening angle of jets in SYM theory evolve as they propagate through the strongly coupled plasma of that theory. We define the rate of energy loss and the jet opening angle in a straightforward fashion directly in the gauge theory before calculating both holographically, in the dual gravitational description. In this way, we rederive the previously known result for without the need to introduce a finite slab of plasma. We obtain a striking relationship between the initial opening angle of the jet, which is to say the opening angle that it would have had if it had found itself in vacuum instead of in plasma, and the thermalization distance of the jet. Via this relationship, we show that SYM jets with any initial energy that have the same initial opening angle and the same trajectory through the plasma experience the same fractional energy loss. We also provide an expansion that describes how the opening angle of the SYM jets increases slowly as they lose energy, over the fraction of their lifetime when their fractional energy loss is not yet large. We close by looking ahead toward potential qualitative lessons from our results for QCD jets produced in heavy collisions and propagating through quark-gluon plasma.

    ↳ hep-thhep-phnucl-thJHEP(2016)·64 citations
  6. 06

    Holographic thermalization with initial long range correlation

    Shu Lin🇨🇳

    We studied the evolution of Wightman correlator in a thermalizing state modeled by AdS_3-Vaidya background. We gave a prescription for calculating Wightman correlator in coordinate space without using any approximation. For equal-time correlator , we obtained an enhancement factor due to long range correlation present in the initial state. This was missed by previous studies based on geodesic approximation. We found that the long range correlation in initial state does not lead to significant modification to thermalization time as compared to known results with generic initial state. We also studied spatially integrated Wightman correlator and showed evidence on the distinction between long distance and small momentum physics for an out-of-equilibrium state. We also calculated radiation spectrum of particle weakly coupled to and found lower frequency mode approaches thermal spectrum faster than high frequency mode.

    ↳ hep-thhep-phnucl-thPRD(2016)·4 citations

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first authorsco-authorsvia INSPIRE