B. Kämpfer
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View article: Note on Klein–Nishina effect in strong-field QED: the case of nonlinear Compton scattering
Note on Klein–Nishina effect in strong-field QED: the case of nonlinear Compton scattering Open
Suitably normalized differential probabilities of one-photon emission in external electromagnetic fields are compared to quantify the transit of nonlinear Compton scattering to linear Compton scattering, described by the Klein–Nishina form…
View article: Strong-field QED in the Furry-picture momentum-space formulation: Ward identities and Feynman diagrams
Strong-field QED in the Furry-picture momentum-space formulation: Ward identities and Feynman diagrams Open
The impact of a strong electromagnetic background field on otherwise perturbative QED processes is studied in the momentum-space formulation. The univariate background field is assumed to have finite support in time, thus being suitable to…
View article: Positron energy distribution in a factorized trident process
Positron energy distribution in a factorized trident process Open
We estimate the energy distribution of positrons produced in the interaction of ultra-relativistic electrons with a high-intensity laser beam. The underlying trident process is factorized on the probabilistic level. That is, we deploy a tw…
View article: Holographic bottomonium formation in a cooling strong-interaction medium\n at finite baryon density
Holographic bottomonium formation in a cooling strong-interaction medium\n at finite baryon density Open
The shrinking of the bottomonium spectral function towards narrow\nquasi-particle states in a cooling strong-interaction medium at finite baryon\ndensity is followed within a holographic bottom-up model. The 5-dimensional\nEinstein-dilaton…
View article: Impact of laser polarization on <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>q</mml:mi></mml:math>-exponential photon tails in nonlinear Compton scattering
Impact of laser polarization on -exponential photon tails in nonlinear Compton scattering Open
Non-linear Compton scattering of ultra-relativistic electrons traversing\nhigh-intensity laser pulses generates also hard photons. These photon\nhigh-energy tails are considered for parameters in reach at the forthcoming\nexperiments LUXE …
View article: Nonperturbative signatures of nonlinear Compton scattering
Nonperturbative signatures of nonlinear Compton scattering Open
The probabilities of various elementary laser - photon - electron/positron\ninteractions display in selected phase space and parameter regions typical\nnon-perturbative dependencies such as $\\propto {\\cal P} \\exp\\{- a E_{crit}\n/E\\}$,…
View article: Quarkonia formation in a holographic gravity-dilaton background describing QCD thermodynamics
Quarkonia formation in a holographic gravity-dilaton background describing QCD thermodynamics Open
A holographic model of probe quarkonia is presented, where the dynamical gravity-dilaton background is adjusted to the thermodynamics of 2 +1 flavor QCD with physical quark masses. The quarkonia action is modified to account for a systemat…
View article: Dynamical freeze-out phenomena: The case of $K^\pm, \phi$ transverse momentum spectra in collisions of Au(1.23 A GeV) + Au
Dynamical freeze-out phenomena: The case of $K^\pm, \phi$ transverse momentum spectra in collisions of Au(1.23 A GeV) + Au Open
We argue on a continuous (dynamical) kinetic freeze-out of $K^\pm, \phi$ observed at midrapidity in collisions Au(1.23 A GeV) + Au. The simulations by means of a transport model of BUU type point to time independent transverse momentum slo…
View article: "Table 1 - Multiplicities and effective Temperatures" of "Sub-threshold production of K$^{0}_{s}$ mesons and ${\Lambda}$ hyperons in Au(1.23A GeV)$+$Au"
"Table 1 - Multiplicities and effective Temperatures" of "Sub-threshold production of K$^{0}_{s}$ mesons and ${\Lambda}$ hyperons in Au(1.23A GeV)$+$Au" Open
$K^{0}_{S}$ and $\Lambda$ multiplicities in full phase space and inverse slopes at mid-rapidity $T_{Eff}$ for a given centrality.
View article: Nonlinear Breit-Wheeler process in short laser double pulses
Nonlinear Breit-Wheeler process in short laser double pulses Open
The non-linear (strong-field) Breit-Wheeler $e^+e^-$ pair production by a\nprobe photon traversing two consecutive short and ultra short (sub-cycle) laser\npulses is considered within a QED framework. The temporal shape of the pulses\nand …
View article: Holographic vector mesons in a dilaton background
Holographic vector mesons in a dilaton background Open
Within a holographic framework, we consider vector mesons riding on a\ngravity-dilaton background. The latter one is determined directly from a\nSchr\\"odinger equivalent potential which delivers a proper $\\rho$ meson Regge\ntrajectory. T…
View article: Propagation of Vector-Meson Spectral-Functions in a BUU Type Transport Model: Application to Di-Electron Production
Propagation of Vector-Meson Spectral-Functions in a BUU Type Transport Model: Application to Di-Electron Production Open
The time evolution of vector-meson spectral-functions is studied within a kinetic theory approach.We implement this formalism in a BUU type transport model.Applications focus on ! and !mesons being important pieces for the interpretation o…
View article: Holographic entanglement entropy in the QCD phase diagram with a critical point
Holographic entanglement entropy in the QCD phase diagram with a critical point Open
We calculate the holographic entanglement entropy for the holographic QCD\nphase diagram considered in [Knaute, Yaresko, K\\"ampfer (2017),\narXiv:1702.06731] and explore the resulting qualitative behavior over the\ntemperature-chemical po…
View article: Afterglow of the dynamical Schwinger process: Soft photons amass
Afterglow of the dynamical Schwinger process: Soft photons amass Open
We consider the conversion of an electric field into photons as a secondary\nprobe of the dynamical Schwinger process. In spatially homogeneous electric\nfields, quantum fluctuations of electron-positron ($e^+e^-$) pairs are lifted\non the…
View article: Field induced phase transition in the few photon regime
Field induced phase transition in the few photon regime Open
Some features of the field induced phase transition accompanied by the vacuum creation of an electron-positron plasma (EPP) in strong time-dependent electric fields have been discussed in the work [1] in the domain of the tunneling mechani…
View article: Residual currents generated from vacuum by an electric field pulse in 2+1 dimensional QED models
Residual currents generated from vacuum by an electric field pulse in 2+1 dimensional QED models Open
\nIn the framework of strong field QED, the generation of a residual alternating polarization current is demonstrated, which remains after switching off an external field pulse. This effect is stipulated by inertial properties of the physi…
View article: Holographically emulating sequential versus instantaneous disappearance of vector mesons in a hot environment
Holographically emulating sequential versus instantaneous disappearance of vector mesons in a hot environment Open
Descent extensions of the soft-wall model are used to accommodate two\nvariants of Regge trajectories of vector meson excitations. At non-zero\ntemperatures, various options for either sequential or instantaneous\ndisappearance of vector m…
View article: Hydrodynamic modeling of a pure-glue initial scenario in high-energy hadron and heavy-ion collisions
Hydrodynamic modeling of a pure-glue initial scenario in high-energy hadron and heavy-ion collisions Open
Partonic matter produced in the early stage of ultrarelativistic nucleus-nucleus collisions is assumed to be composed mainly of gluons, and quarks and antiquarks are produced at later times. The comparable hydrodynamic simulations of heavy…
View article: Electromagnetic probes of a pure-glue initial state in nucleus-nucleus collisions at energies available at the CERN Large Hadron Collider
Electromagnetic probes of a pure-glue initial state in nucleus-nucleus collisions at energies available at the CERN Large Hadron Collider Open
Partonic matter produced in the early stage of ultrarelativistic\nnucleus-nucleus collisions is assumed to be composed mainly of gluons, and\nquarks and antiquarks are produced at later times. To study the implications of\nsuch a scenario,…
View article: Electromagnetic probes of a pure-glue initial state in nucleus-nucleus collisions at LHC
Electromagnetic probes of a pure-glue initial state in nucleus-nucleus collisions at LHC Open
Partonic matter produced in the early stage of ultrarelativistic nucleus-nucleus collisions is assumed to be composed mainly of gluons, and quarks and antiquarks are produced at later times. To study the implications of such a scenario, th…
View article: Laser assisted Breit-Wheeler and Schwinger processes
Laser assisted Breit-Wheeler and Schwinger processes Open
The assistance of an intense optical laser pulse on electron-positron pair production by the Breit-Wheeler and Schwinger processes in XFEL fields is analyzed. The impact of a laser beam on high-energy photon collisions with XFEL photons co…
View article: Caustic structures in x-ray Compton scattering off electrons driven by a short intense laser pulse
Caustic structures in x-ray Compton scattering off electrons driven by a short intense laser pulse Open
We study the Compton scattering of x-rays off electrons that are driven by a relativistically intense short optical laser pulse. The frequency spectrum of the laser-assisted Compton radiation shows a broad plateau in the vicinity of the la…
View article: Dynamical Schwinger process in a bifrequent electric field of finite duration: Survey on amplification
Dynamical Schwinger process in a bifrequent electric field of finite duration: Survey on amplification Open
The electron-positron pair production due to the dynamical Schwinger process in a slowly oscillating strong electric field is enhanced by the superposition of a rapidly oscillating weaker electric field. A systematic account of the enhance…
View article: Photon emission within the linear sigma model
Photon emission within the linear sigma model Open
Soft-photon emission rates are calculated within the linear sigma model. The\ninvestigation is aimed at answering the question to which extent the\nemissivities map out the phase structure of this particular effective model of\nstrongly in…