This is shown in calculations of the light emission of so-called quark-gluon plasmas, which are created in such collisions for extremely short periods of time. Under certain conditions, double flashes are created, which could be utilized in the future to visualize the dynamics of atomic nuclei. (Physical Review Letters, 07.10.2009)
Collisions of heavy ions in a large accelerator facility (schematic). Under certain conditions, double light flashes of a few yoctoseconds duration can be emitted. MPI for Nuclear Physics
Temporal evolution of the quark-gluon plasma. Two ions (colored disks) collide along the beam collision axis (black double arrow). Image (a) shows the time immediately after the collision. The plasma (orange area) shines light (wavy arrows) in all directions, so that a first pulse in the direction of the detector (green semi-circle) is formed. (b) After some time, the inner dynamics of the plasma will cause light to be preferentially radiated perpendicular to the direction of flight of the ions. During this time no light is emitted into the direction of the detector which is placed close to the collision axis. In (c) the plasma radiates again in all directions, so that the second pulse is emitted in the direction of the detector. MPI for Nuclear Physics
For high-precision spectroscopy and structural studies of molecules, short light flashes with lowest possible wavelength, i.e., high photon energy, are required. Currently, x-ray flashes of some attosecond (a quintillionth of a second, 10-18 s) duration are accessible experimentally. Even shorter pulses with even higher photon energy would improve the temporal and spatial resolution, or would allow for the investigation of even smaller structures, such as for example atomic nuclei. In so-called pump-probe experiments, two light pulses of exactly controllable distance are utilized to observe rapid system changes in slow motion.
Calculations at the Max Planck Institute for Nuclear Physics have now shown that high-energy heavy ion collisions at large particle accelerators are suitable as light sources for the desired single and double pulses. This is due to the remarkable properties of quark-gluon plasmas.
The quark-gluon plasma is a state of matter of which the universe consisted right after the big bang. In this state, the temperatures are so high that even the constituents of atomic nuclei, the neutrons and protons, are split into their constituents, the quarks and gluons. Such a state of matter can nowadays be realized in modern colliders.
In the collision of heavy ions (i.e. atoms of heavy elements from which all electrons have been removed) at relativistic velocities, such a quark-gluon plasma is created for a few yoctoseconds at the size of a nucleus (Figure 1). Among many other particles, it also creates photons of a few GeV (billion electron volts) energy, so-called gamma radiation. These high-energy flashes of light are as short as the lifetime the quark-gluon plasma and consist of only a few photons.
The researchers have simulated the time-dependent expansion and internal dynamics of the quark-gluon plasma. It was found that at some intermediate time the photons are not emitted in all directions, but preferably perpendicular to the collision axis. A detector that is placed close to the collision axis will measure practically nothing during this period. Therefore, overall it detects a double pulse (Figure 2). By suitable choice of geometry of the setup and observing direction, the double pulses can in principle be selectively varied. Thus, they open up the possibility of future pump-probe experiments in the yoctosecond range at high energies. This could lead to a time-resolved observation of processes in atomic nuclei. Conversely, a detailed analysis of the gamma-ray flashes would allow to draw conclusions about the quark-gluon plasma.
Contact:PD Dr. Jörg Evers
Dr. Bernold Feuerstein | Max-Planck-Gesellschaft
Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State
What do Netflix, Google and planetary systems have in common?
02.12.2016 | University of Toronto
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy