Institute For Kernphysik

fur, Germany

Institute For Kernphysik

fur, Germany
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Hirvonen L.M.,King's College London | Becker W.,Becker and Hickl GmbH | Milnes J.,Photek Ltd. | Conneely T.,Photek Ltd. | And 4 more authors.
Applied Physics Letters | Year: 2016

We perform wide-field time-correlated single photon counting-based fluorescence lifetime imaging (FLIM) with a crossed delay line anode image intensifier, where the pulse propagation time yields the photon position. This microchannel plate-based detector was read out with conventional fast timing electronics and mounted on a fluorescence microscope with total internal reflection (TIR) illumination. The picosecond time resolution of this detection system combines low illumination intensity of microwatts with wide-field data collection. This is ideal for fluorescence lifetime imaging of cell membranes using TIR. We show that fluorescence lifetime images of living HeLa cells stained with membrane dye di-4-ANEPPDHQ exhibit a reduced lifetime near the coverslip in TIR compared to epifluorescence FLIM. © 2016 Author(s).

Klein-Bosing C.,Institute For Kernphysik | Klein-Bosing C.,Helmholtz Center for Heavy Ion Research
Journal of Physics G: Nuclear and Particle Physics | Year: 2011

For a quantitative interpretation of reconstructed jet properties in heavy-ion collisions, it is paramount to characterize the contribution from the underlying event and the influence of background fluctuations on the jet signal. In addition to the pure number fluctuations, region-to-region correlated background within one event can enhance or deplete locally the level of background and modify the jet energy. We show the first detailed assessment of background effects using different probes embedded into heavy-ion data and quantify their influence on the reconstructed jet spectrum. © CERN 2011. Published under licence by IOP Publishing Ltd.

Langanke K.,Helmholtz Center for Heavy Ion Research | Langanke K.,Institute For Kernphysik | Langanke K.,Frankfurt Institute for Advanced Studies | Schatz H.,Michigan State University
Physica Scripta | Year: 2013

Short-lived exotic nuclei play essential roles in the dynamics of many stellar objects and their associated nucleosynthesis, including core-collapse and thermonuclear supernovae, novae, x-ray bursters and mass-accreting neutron stars in binary systems. To produce such nuclei and to study their properties requires radioactive ion-beam facilities. While the short-lived nuclei on the neutron-deficient side of the chart of nuclei are often within reach at current experimental facilities, albeit not necessarily with the beam intensities needed, the extremely neutron-rich nuclei, required for an understanding of the synthesis of heavy elements in the Universe by the astrophysical r-process, have to wait, in most cases, for the next-generation radioactive ion-beam facilities. This paper discusses highlights of recent experimental and theoretical advances in determining the properties of exotic nuclei and the further need for reliable studies of astrophysical objects such as supernovae, novae, x-ray bursters and neutron stars. © 2013 The Royal Swedish Academy of Sciences.

Klein-Boesing C.,Institute For Kernphysik | Klein-Boesing C.,Helmholtz Center for Heavy Ion Research | McLerran L.,Brookhaven National Laboratory | McLerran L.,Central China Normal University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

Geometric scaling is a property of hadronic interactions predicted by theories of gluon saturation and expressing rates in terms of dimensionless ratios of transverse momentum to the saturation momentum. In this paper we consider production of photons in pp, dAu and AuAu collisions at sNN=200GeV (RHIC) and in PbPb collisions at sNN=2760GeV (LHC) and show that the yield of direct photons in the transverse momentum range 1GeV < p T ≤ 4GeV/c satisfies geometric scaling. Excellent agreement with geometric scaling is obtained with the only free parameter of the saturation momentum determined previously via the dependence of the saturation momentum upon Bjorken x and centrality. © 2014 The Authors.

Thomas A.,Institute For Kernphysik
EPJ Web of Conferences | Year: 2016

The A2 Collaboration at the Mainz Microtron MAMI is measuring photon absorption cross section using circularly and linearly polarized photons up to energies of 1.6 GeV. The photons are produced in the 'Bremsstrahlungs' process, the energy is determined by a dedicated tagging system. The Crystal Ball-TAPS detector system with its high capability to cope with multi photon final states is used to acquire data with a variety of nonpolarized and spin polarized targets. Physical goals are the investigation of the nucleons excitation spectrum via single and double meson photoproduction and in addition a detailed determination of meson decays in precision experiments. We have started a program to measure double polarised Compton scattering to determine the nucleons scalar and spin polarisibilities. In this proceedings recent results from A2 collaboration. © The Authors, published by EDP Sciences, 2016.

Weidenkaff P.,Institute For Kernphysik
Journal of Physics: Conference Series | Year: 2016

The study of mesons and baryons which contain at least one charm quark is referred to as open charm physics. It offers the possibility to study up-type quark transitions. Since the c quark can not be treated in any mass limit, theoretical predictions are difficult and experimental input is crucial. BESIII collected large data samples of e+e- collisions at several charm thresholds. The at-threshold decay topology offers special opportunities to study open charm decays. We present a selection of recent BESIII results. The D + s decay constant is measured using the leptonic decays to μ+ν and τ+ ν. Using the semi-leptonic decays of D 0 and Dto Ke+νe and πe+νe, a measurement of the form factors f + K (q 2) and f + π (q 2) is performed and furthermore, we show preliminary results of a model independent measurement of the strong phase difference between D 0 and D 0 in the channel D 0 → K s 0π+π- which is an experimental input to the measurement of the CKM angle γ/φ3. © Published under licence by IOP Publishing Ltd.

Skurzok M.,Jagiellonian University | Moskal P.,Jagiellonian University | Moskal P.,Institute For Kernphysik | Krzemie W.,Jagiellonian University
Progress in Particle and Nuclear Physics | Year: 2012

The existence of η-mesic nuclei in which the η meson is bound with nucleus by means of the strong interaction was postulated already in 1986, however till now no experiment confirmed it empirically. Discovering of this new kind of an exotic nuclear matter would be very important as it might allow for better understanding of the η meson structure and its interaction with nucleons. The search for η-mesic helium ( 4He-η) is carried out with high statistic and high acceptance by means of the WASA detector, installed at the cooler synchrotron COSY in the Research Center Jlich. The search is conducted via the measurement of the excitation function for the chosen decay channels of the 4He-η system. In the experiment performed in November 2010 two reactions dd→( 4He -η)bs→ 3Hep π- and dd→( 4He -η)bs→ 3Hen π0 were measured with the beam momentum ramped from 2.127 GeV/c to 2.422 GeV/c. The report includes the description of experimental method and status of the measurement. © 2012 Elsevier B.V. All rights reserved.

Heide M.,Institute For Kernphysik
Journal of Physics: Conference Series | Year: 2014

ALICE measured electrons from inclusive heavy-avour hadron decays and beautyhadron decays at mid-rapidity in pp collisions at S = 7 TeV and 2.76 TeV and p-Pb collisions at SNN = 5.02 TeV. For both pp collision energies, pT-differential electron production cross sections are presented and compared to pQCD predictions. For p-Pb collisions, the pT-dependent nuclear modification factor of electrons from inclusive heavy-avour hadron decays is presented.

Baunack S.,Institute For Kernphysik
Hyperfine Interactions | Year: 2011

The A4 collaboration at the MAMI accelerator at Mainz investigates the contribution of strange quarks to the form factors of the nucleon by measuring the parity violating asymmetry APV in the cross section of elastic scattering of longitudinally polarized electrons off hydrogen and deuterium. Recently, measurements at backward angles at a four momentum transfer of Q2 = 0.22 GeV2 were completed. Together with previous results at forward angles at the same momentum transfer, the strange electric and magnetic form factors GEs and GMs can be disentangled. © 2011 Springer Science+Business Media B.V.

Huege T.,Institute For Kernphysik
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2010

In small-scale experiments such as CODALEMA and LOPES, radio detection of cosmic rays has demonstrated its potential as a technique for cosmic ray measurements up to the highest energies. Radio detection promises measurements with high duty-cycle, allows a direction reconstruction with very good angular resolution, and provides complementary information on energy and nature of the cosmic ray primaries with respect to particle detectors at ground and fluorescence telescopes. Within the Pierre Auger Observatory, we tackle the technological and scientific challenges for an application of the radio detection technique on large scales. Here, we report on the results obtained so far using the Southern Auger site and the plans for an engineering array of radio detectors covering an area of ∼20 km2. © 2009 Elsevier B.V. All rights reserved.

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