S. Lökòs

We generalize a previously known class of exact analytic solutions of relativistic perfect fluid hydrodynamics for the first time to arbitrary temperature-dependent Equation of State. We investigate special cases of this class of solutions, in particular, we present hydrodynamical solutions with an Equation of State determined from lattice QCD calculations. We discuss the phenomenological relevance of these solutions as well.

Within the model of partial chemical equilibrium (PCE) we calculate the multiplicity ratios of selected unstable resonances to given stable species. We focus on those ratios that have been measured either in Pb+Pb collisions at the LHC or in Au+Au collisions at the top RHIC energy. The model provides an interpretation how in an expanding hadronic fireball with decreasing temperature the final numbers of stable hadrons after decays of all resonances remain unchanged. Each stable species acquires its own chemical potential and the resonances are kept in equilibrium with them. Multiplicities of unstable resonances provide a test of this scenario. We observe that the ratios of $K^{*}/K$ and $\rho^0/\pi$ fit reasonably well into the picture of single kinetic freeze-out of the single-particle spectra, but the $\phi$-meson and hyperon resonances are not reproduced by this model.

In high energy heavy ion collisions a new state of matter, the strongly coupled quark gluon plasma is formed that exhibits the similar properties as our Universe had just a couple of microseconds after the Big Bang, hence such collisions are usually referred as Little Bangs. Subsequent investigations showed that the created medium is a nearly perfect fluid whose time evolution can be described by hydrodynamic models. The distribution of the hadrons that are created in the freeze-out after a rapid expansion carry information about the final state. On the other hand, with penetrating probes, e.g., with direct photons, one can model the time evolution of the quark gluon plasma. In this paper, we present a hydrodynamic model that was inspired by an analytical solution of relativistic hydrodynamics, calculate the invariant transverse momentum spectrum and the elliptic flow of direct photons and compare our results to LHC ALICE data to obtain the value of the model parameters. Based on the the results we give an estimation for the initial temperature of the plasma.

We formulate a generalisation of the blast-wave model which is suitable for the description of higher-order azimuthal anisotropies of the hadron production. The model includes anisotropy in the density profile as well as an anisotropy in the transverse expansion velocity field. We then study how these two kinds of anisotropies influence the single-particle distributions and the correlation radii of two-particle correlation functions. Particularly we focus on the third-order anisotropy and consideration is given averaging over different orientations of the event plane.

The original Oberbeck–Boussinesq (OB) equations which are the coupled two dimensional Navier–Stokes(NS) and heat conduction equations have been investigated by E.N. Lorenz half a century ago with Fourier series and opened the way to the paradigm of chaos. In our former study—Chaos, Solitons and Fractals 78, 249 (2015)—we presented fully analytic solutions for the velocity, pressure and temperature fields with the aim of the self-similar Ansatz and gave a possible explanation of the Rayleigh–Bènard convection cells. Now we generalize the Oberbeck–Boussinesq hydrodynamical system, going beyond the first order Boussinesq approximation and consider a non-linear temperature coupling. We investigate more general, power law dependent fluid viscosity or heat conduction material equations as well. Our analytic results obtained via the self-similar Ansatz may attract the interest of various fields like meteorology, oceanography or climate studies.

Investigation of momentum space correlations of particles produced in high energy reactions requires taking final state interactions into account, a crucial point of any such analysis. Coulomb interaction between charged particles is the most important such effect. In small systems like those created in e+e- or p+p collisions, the so-called Gamow factor (valid for a point-like particle source) gives an acceptable description of the Coulomb interaction. However, in larger systems such as central or mid-central heavy ion collisions, more involved approaches are needed. In this paper we investigate the Coulomb final state interaction for Levy-type source functions that were recently shown to be of much interest for a refined description of the space-time picture of particle production in heavy-ion collisions.

Measurements of momentum space correlations in heavy ion reactions are a unique tools to investigate the properties of the created medium. However, these analyses require the careful handling of the final state interactions such as the Coulomb repulsion of the involved particles. In small systems such as $e^+ + e^-$ or $p+p$ the well-known Gamow factor gives an acceptable description but in the case of extended sources like that are created in heavy ion collisions, a more sophisticated approach has to be developed. In this paper we expand our previous work on the investigation of the Coulomb final state interaction in the presence of a L\'evy source. Such sources were shown to be a statistically acceptable assumption to describe the quantumstatistical correlation functions in high energy heavy ion reactions.

Investigation of femtoscopic correlation functions in relativistic heavy ion reactions is an important tool to access the space-time structure of particle production in the strongly interacting Quark Gluon Plasma (sQGP).The shape of the source, and thus the shape of the correlation functions, is often assumed to be Gaussian, but experimental results found evidence for heavy tails in the source distribution of pions.Recent analysis revealed that the statistically correct assumption could be the so-called Lévy distribution.The detailed investigation of correlation functions in various systems may shed light on the location of the critical endpoint on QCD (Quantum Chromodynamics) phase diagram.It could also reveal if there is partially coherent pion production or could indicate the possible in-medium mass modification of the η meson due to the (partial) restoration of the U A (1) axial symmetry.These phenomena could depend on the system size and on the collision energy.A detailed centrality-dependent analysis could explore the multiplicity dependencies of the Lévy parameters, and thus the critical and thermodynamical properties of the sQGP, and could give information about the above mentioned processes.In this paper, we present the status of the centrality dependent measurements of two-pion Lévy Bose-Einstein correlation functions √ s NN = 200 GeV Au+Au collisions at PHENIX.

Summary of the long term data taking, related to one of the proposed next generation ground-based gravitational detector's location is presented here. Results of seismic and infrasound noise, electromagnetic attenuation and cosmic muon radiation measurements are reported in the underground Matra Gravitational and Geophysical Laboratory near Gyöngyösoroszi, Hungary. The collected seismic data of more than two years is evaluated from the point of view of the Einstein Telescope, a proposed third generation underground gravitational wave observatory. Applying our results for the site selection will significantly improve the signal to nose ratio of the multi-messenger astrophysics era, especially at the low frequency regime.

The Buda-Lund hydro model describes an expanding ellipsoidal fireball, and fits the observed elliptic flow and oscillating HBT radii successfully. Due to fluctuations in energy depositions, the fireball shape however fluctuates on an event-by-event basis. The transverse plane asymmetry can be translated into a series of multipole anisotropy coefficients. These anisotropies then result in measurable momentum-space anisotropies, to be measured with respect to their respective symmetry planes. In this paper we detail an extension of the Buda-Lund model to multipole anisotropies and investigate the resulting flow coefficients and oscillations of HBT radii.

The L3 detector is designed to measure the muon momentum with a 2% resolution at p = 45 GeV/c. We discuss here the systems we developed to reach the required accuracy and control the mechanical alignment at running time. We also report on the test done on the muon spectrometer with UV lasers and cosmic rays.

Measurement of quantumstatistical correlation functions in high energy nuclear physics is an important tool to investigate the QCD phase diagram. It may be used to search for the critical point, and also to understand underlying processes such as in-medium mass modifications or partially coherent particle production. Furthermore, the measurements of the femtoscopic correlation functions shed light on the space-time structure of particle production. Consequently, the precise measurements and description of the correlation functions are essential. The shape of two-pion Bose-Einstein correlation functions were often assumed to be Gaussian, but the recent precision of the experiments reveals that the statistically correct assumption is the more general Levy-distribution. In this paper we present the recent results of the measurements of two-pion Levy-stable Bose-Einstein correlation functions in Au+Au collisions at PHENIX

Measurements of cosmic rays in the L3 multisampling chambers are presented. The study of tracks with polar angles from 30° < θ < 130° w.r.t. the wires show increasing pulse height like 1/sin θ. Using inclined tracks, we find a ±1.5 cm region of reduced accuracy near the glass supports of the 5.4 m long wires.

The Buda-Lund model describes an expanding hydrodynamical system with ellipsoidal symmetry and fits the observed elliptic flow and oscillating HBT radii successfully. The ellipsoidal symmetry can be characterized by the second order harmonics of the transverse momentum distribution, and it can be also observed in the azimuthal oscillation of the HBT radii measured versus the second order reaction plane. The model may have to be changed to describe the experimentally indicated higher order asymmetries. In this paper we detail an extension of the Buda-Lund hydro model to investigate higher order flow harmonics and the triangular dependence of the azimuthally sensitive HBT radii.

The Buda-Lund model describes an expanding hydrodynamical system with ellipsoidal symmetry and fits the observed elliptic flow and oscillating HBT radii successfully.The ellipsoidal symmetry can be characterized by the second order harmonics of the transverse momentum distribution, and it can be also observed in the azimuthal oscillation of the HBT radii measured versus the second order reaction plane.The model may have to be changed to describe the experimentally indicated higher order asymmetries.In this paper we detail an extension of the Buda Lund hydro model to investigate higher order flow harmonics and the triangular dependence of the azimuthally sensitive HBT radii.

The Buda-Lund model describes an expanding hydrodynamical system with ellipsoidal symmetry and fits the observed elliptic flow and oscillating HBT radii successfully. The ellipsoidal symmetry can be characterized by the second order harmonics of the transverse momentum distribution, and it can be also observed in the azimuthal oscillation of the HBT radii measured versus the second order reaction plane. The model may have to be changed to describe the experimentally indicated higher order asymmetries. In this paper we detail an extension of the Buda-Lund hydro model to investigate higher order flow harmonics and the triangular dependence of the azimuthally sensitive HBT radii.

The original Oberbeck-Boussinesq (OB) equations which are the coupled two dimensional Navier-Stokes(NS) and heat conduction equations have been investigated by E.N. Lorenz half a century ago with Fourier series and opened the way to the paradigm of chaos. In our former study-Chaos, Solitons and Fractals78, 249 (2015)-we presented fully analytic solutions for the velocity, pressure and temperature fields with the aim of the self-similar Ansatz and gave a possible explanation of the Rayleigh--Benard convection cells. Now we generalize the Oberbeck-Boussinesq hydrodynamical system, going beyond the first order Boussinesq approximation and consider a non-linear temperature coupling. We investigate more general, power law dependent fluid viscosity or heat conduction material equations as well. Our analytic results obtained via the self-similar Ansatz may attract the interest of various fields like meteorology, oceanography or climate studies.

The original Oberbeck-Boussinesq (OB) equations which are the coupled two dimensional Navier-Stokes(NS) and heat conduction equations have been investigated by E.N. Lorenz half a century ago with Fourier series and opened the way to the paradigm of chaos. In our former study-Chaos, Solitons and Fractals78, 249 (2015)-we presented fully analytic solutions for the velocity, pressure and temperature fields with the aim of the self-similar Ansatz and gave a possible explanation of the Rayleigh--B\`enard convection cells. Now we generalize the Oberbeck-Boussinesq hydrodynamical system, going beyond the first order Boussinesq approximation and consider a non-linear temperature coupling. We investigate more general, power law dependent fluid viscosity or heat conduction material equations as well. Our analytic results obtained via the self-similar Ansatz may attract the interest of various fields like meteorology, oceanography or climate studies.

Intensity interferometry originates from the field of radio astronomy on the trace of Robert Hanbury Brown and Richard Quincy Twiss. In high energy physics, the phenomena was discovered by Goldhaber, Goldhaber, Lee and Pais. In radio astronomy the method is exceeded by more modern approaches but in high energy physics, the measurements of Hanbury Brown-Twiss (HBT) or Goldhaber-Goldhaber-Lee-Pais (GGLP) type of correlations are important tools to access the spatio-temporal properties of the matter under extreme conditions on subatomic scales. In this paper, I review recent experimental results from energies of the Relativistic Heavy Ion Collider (RHIC) to the Large Hadron Collider (LHC) and discuss their possible implication on the equation of state of the QCD matter.

In high energy collisions, a dense, strongly interacting medium could be created, the quark gluon plasma. In rapid expansion, from the soup of quarks and gluons a gas of resonance and stable particles is formed at the chemical freeze-out and after that, as the system cools down, the kinetic freeze-out takes place and interaction between particles ceases. By measuring resonance ratios one could get information about the dominant physical processes in the intermediate temperature ranges, i.e. between the chemical and kinetic freeze-out. These quantities are measured at RHIC and LHC energies. In the present analysis we employ the hadron resonance gas model assuming partial chemical equilibrium to characterize these measured data. We calculate the ratios of several resonances to their stable counterpart and compare these model calculations to available experimental data.

A lidar system employing a diode laser pumped Nd:YLF laser and photon counting technique is described for use in automated cloud and aerosol measurements. A Nd:YLF laser provides 523 nm 10 (mu) J/pulse energy at 2500 Hz repetition rate. A coaxial configuration is used for transmitting laser pulse and receiving the signal with a 0.2 m Schmidt-Cassegrain telescope. An avalanche photodiode is used for back scattered photon counting in Geiger mode. This micro pulse lidar (MPL) is capable to detect subvisible cirrus and boundary layer within 10 second averaging time. Also the MPL takes back scattered signal at four different spatial resolutions of 30 m, 75 m, 150 m, and 300 m to meet various user requirements. The detected signal is processed and displayed on a personal computer. The 32 bit data processing software is running on the Window 95 platform.

Measurement of quantumstatistical correlation functions in high energy nuclear physics is an important tool to investigate the QCD phase diagram. It may be used to search for the critical point, and also to understand underlying processes such as in-medium mass modifications or partially coherent particle production. Furthermore, the measurements of the femtoscopic correlation functions shed light on the space-time structure of particle production. Consequently, the precise measurements and description of the correlation functions are essential. The shape of two-pion Bose-Einstein correlation functions were often assumed to be Gaussian, but the recent precision of the experiments reveals that the statistically correct assumption is the more general Levy-distribution. In this paper we present the recent results of the measurements of two-pion Levy-stable Bose-Einstein correlation functions in Au+Au collisions at PHENIX

The usual interpretation of Bose-Einstein correlations (BEC) of identical boson pairs relates the width of the peak in the correlation function at small relative four-momentum to the spatial extent of the source of the bosons. However, in the τ-model, which successfully describes BEC in hadronic Z decay, the width of the peak is related to the temporal extent of boson emission. Some new checks on the validity of both the τ-model and the usual descriptions are presented.

Measurement of quantumstatistical correlation functions in high energy nuclear physics is an important tool to investigate the QCD phase diagram. It may be used to search for the critical point, and also to understand underlying processes such as in-medium mass modifications or partially coherent particle production. Furthermore, the measurements of the femtoscopic correlation functions shed light on the space-time structure of particle production. Consequently, the precise measurements and description of the correlation functions are essential. The shape of two-pion Bose-Einstein correlation functions were often assumed to be Gaussian, but the recent precision of the experiments reveals that the statistically correct assumption is the more general L\'evy-distribution. In this paper we present the recent results of the measurements of two-pion L\'evy-stable Bose-Einstein correlation functions in Au+Au collisions at PHENIX

Abstract A drift chamber which measures the drift time of photoelectrons emitted from the cathode surface by means of a UV laser pulse has been built. The chamber is used for monitoring the drift time changes in the muon chambers of the L3 detector at CERN due to changes of gas parameters with the accuracy of 0.1%. The construction and experiments to determine the accuracy and stability of the device are described.

Quantum-statistical correlation measurements in high-energy physics represent an important tool to obtain information about the space-time structure of the particle-emitting source. There are several final state effects which may modify the measured femtoscopic correlation functions. One of these may be the interaction of the investigated particles with the expanding hadron gas, consisting of the other final state particles. This may cause the trajectories - and hence the phases - of the quantum-correlated pairs to be modified compared to free streaming. The resulting effect and could be interpreted as an Aharonov-Bohm-like phenomenon, in the sense that the possible paths of a quantum-correlated pair represent a closed loop, with an internally present field caused by the hadron gas. In this paper, the possible role of the effect in heavy-ion experiments is presented with analytical calculations and a simple numerical model. The modification of the strength of multi-particle Bose-Einstein correlation functions is investigated, and the is found that in case of sufficiently large source density, this effect may play a non-negligible role.

The upgrade of the Fermilab Tevatron Collider will reduce the present 3.5 microsecond bunch spacing (the time between bunch crossings) to 396 ns and ultimately to 132 ns. The shorter bunch spacing imposes tighter timing requirement on both the signals from the calorimeter and the timing for signal sampling. This change requires the replacement of the DO detector calorimeter front-end electronics. The 2+ /spl mu/s first level (L1) trigger decision time requires to hold the events in the meantime. A high resolution analog memory element (Switched Capacitor Array-SCA) has been developed for this purpose and used in a complex analog memory system (L1 buffers) to minimize the dead time at the front end input. The second level (L2) trigger system has a decision time of 20-100 /spl mu/s. To minimize the dead time further required an additional analog buffer to free up the L1 buffers before the L2 decision is completed and to hold the accepted events until they can be transferred to the third level (L3) trigger. A flexible Timing And Calibration control (TAC) system is under development for buffer management, sampling synchronization, trigger event read out and calibration control. The TAC system is also responsible for the data flow control from the front end to the (L3) trigger.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The planned upgrade of the Tevatron Collider at Fermilab will provide a higher luminosity and shorter bunch crossing than the present conditions, requiring a significant upgrade of the readout electronics for the DO Uranium-Liquid Argon Calorimeter. To study the performance of the new electronics a large scale test system (4608 electronic channels) has been built. Currently the system is instrumented with the old readout electronics. We report on the performance of the system; the developed software for data acquisition and data analysis and preliminary measurements of the new preamplifiers.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Real time noninvasive head injury detection is needed in critical care facilities and triage site with limited resources. One tool missing right now is a small and fast noninvasive sensor which can help urgent care workers to (1) diagnose the location and severity of the injury, (2) to perform on site pre-hospital treatment if necessary, and (3) to make a decision on what kind of further medical action is needed. On the other hand, continuous monitoring of cerebral blood oxygenation is also needed in intensive care unit and in operation rooms. Pseudo-random modulation/near infrared sensor (PRM/NIR sensor) is developed to address these issues. It relies on advanced techniques in diode laser cw modulation and time resolved spectroscopy to perform fast and noninvasive brain tissue diagnostics. Phantom experiments have been conducted to study the feasibility of the sensor. Brain's optical properties are simulated with solutions of intralipid and ink. Hematomas are simulated with bags of paint and hemoglobin immersed in the solution of varies sizes, depths, and orientations. Effects of human skull and hair are studied experimentally. In animal experiment, the sensor was used to monitor the cerebral oxygenation change due to hypercapnia, hypoxia, and hyperventilation. Good correlations were found between NIR measurement parameters and physiological changes induced to the animals.

The pseudo-random modulation/near IR sensor (PRM/NIR Sensor) is a low cost portable system designed for time-resolved tissue diagnosis, especially hematoma detection in the emergency care facility. The sensor consists of a personal computer and a hardware unit enclosed in a box of size 37 X 37 X 31 cm<SUP>3</SUP> and of weight less than 10 kg. Two pseudo-random modulated diode lasers emitting at 670 nm and 810 nm are used in the sensor as light sources. The sensor can be operated either in a single wavelength mode or a true differential mode. Optical fiber bundles are used for convenient light delivery and color filters are used to reject room light. Based on a proprietary resolution- enhancement correlation technique, the system achieves a time resolution better than 40 ps with a PRM modulation speed of 200 MHz and a sampling rate of 1-10 Gs/s. Using the prototype sensor, phantom experiments have been conducted to study the feasibility of the sensor. Brain's optical properties are simulated with solutions of intralipid and ink. Hematomas are simulated with bags of paint and hemoglobin immersed in the solution of varies sizes, depths, and orientations. Effects of human skull and hair are studied experimentally. In animal experiment, the sensor was used to monitor the cerebral oxygenation change due to hypercapnia, hypoxia, and hyperventilation. Good correlations were found between NIR measurement parameters and physiological changes induced to the animals.

Summary form only given. We present measurements of the spectral characteristics of the commercially obtained optical parametric oscillator (OPO) (Continuum model Mirage 800) that reflect its suitability as an on-line differential absorption lidar (DIAL) transmitter.

The high luminosity and short bunch spacing time of the upgraded Tevatron force the calorimeter to replace a significant part of the present electronics. The W mass measurement was used to study the pile-up effects.