We describe here fast optical cameras based on a new silicon pixel sensor, which in combination with the Timepix chips, will provide nanosecond scale time resolution and high quantum efficiency for photons with wavelength between 400 and 1050nm.
Vysokoenergetická fyzika potřebuje pro svá měření a výzkum co nejpřesněji definované vlastnosti srážejících se svazků, proto fyzika urychlovačů je esenciálním aspektem těchto experimentů. Porozumění základům fyziky a technologie svazku poskytuje základ pro oblasti teorie svazku či až inženýrské aplikace. K základům fyziky urychlovačů patří oblasti optické soustavy a příčné dynamice, které...
Pro urychlení elektronů pomocí laserem řízené plazmové vlny je nutné zajistit jejich dostatečný počet v urychlovací fázi. K tomu lze využít několika metod. Jedna z možností je kolize dvou na sebe kolmých laserových impulzů. Hlavní svazek vytváří plazmovou vlnu a vedlejší, který je slabší, do ní injektuje elektrony. V této práci je uveden návrh optické soustavy určené pro přesnou synchronizaci...
Luminozita je veličina, která udává poměr mezi frekvencí interakce a jejím účinným průřezem. Velkou výhodou luminozity je nezávislost na procesu. Ze znalosti luminozity a frekvence interakcí lze spočítat účinný průřez dané interakce. Na urychlovačích, používajících shluky částic ve svazku, je rozšířena metoda určení luminozity nesoucí název po fyziku Simonu van der Meeru. Pomocí této metody,...
Difrakční procesy se ukazují jako velmi velmi dobrá sonda do struktury protonu. Tyto procesy se v 60. letech pokoušela vysvětlit Reggeho teorie pomocí výměny tzv. pomeronu, a to velmi úspěšně. V této přednášce představím koncept této teorie a nahlédneme na ní z pohledu moderní kvantové chromodynamiky.
The high energy limit of QCD can be studied using the Deep inelastic scattering (DIS) at small Bjorken-x. Under these circumstances the gluon density rapidly increases. However the increase is eventually tamed by recombination, as the experimental data suggest us, which leads to the effect called parton saturation. To predict the cross-section of DIS we need to determine the cross-section of...
Using the rcBK evolution equation to calculate the scattering amplitude and from it, the Transverse Momentum Distribution functions can be very useful because of its use in calculation of factorised cross sections. In this contribution, we will address some key aspects of this topic as well as show, how such computation can be carried out.
A compact detector called AD was added to the ALICE apparatus at the beginning of the LHC run 2 in order to extend the trigger capabilities. In this talk we will concentrate on all kinds of boring details about calibration, data reconstruction and quality assurance in order to provide a picture of how a small part of modern high-energy experiment works in the real life.
V příspěvku budou po krátkém úvodu standardního modelu vysvětleny všechny základní pojmy fyziky vysokých energií. Dále bude uvedena QGP a efekty stínění. Podrobněji budou rozebrány efekty produkce těžkých kvarků, především studené jaderné hmoty. Na závěr příspěvku budou shrnuty dosavadní výsledky na experimentech STAR, CMS a ALICE.
In my thesis, I go in for a detector optimisation using mainly the Geant4 toolkit and Allpix-squared, a new Geant4-based program which is currently being developed in collaboration with CERN facility. In particular, I focus on radiation resistible semiconductor monolithic pixel detectors used in space dosimetry.
In this thesis i am focusing on measuring the propheties of quark-gluon plasma via suppresion of mezon $\Upsilon$. This thesis also contains information about basic propheties of quark-gluon plasma and efects that cause suppresion or enhancement of mezon $\Upsilon$.
The subject of my thesis is space radiation detection using semiconductor detectors.
Firstly, simulation of detector response in Geant4 - Monte Carlo based software toolkit is involved. Later, test measurement is carried out on Tandetron accelerator in Řež.
A summary of several papers on the coherent $\rho^0$ photoproduction in ultra-peripheral heavy ion collisions and the comparison of their findings along with model comparisons. 4 papers by the STAR collaboration reporting on Au-Au collisions at $\sqrt{S_{NN}}=130$ GeV, $\sqrt{S_{NN}}=200$ GeV, $\sqrt{S_{NN}}=62.4$ GeV, and one by the ALICE collaboration reporting on Pb-Pb collisions at...
Laser based acceleration technology allows to produce high electric fields with a centimeter-scale device. The basic physics of Laser Wakefield Acceleration is introduced. To get stable mono-energetic electron beam, particles should be firstly injected into the plasma wave. Different types of electron injection are reviewed. The experimental techniques for density measurement above the...
Presenting microscopic quantum hardware generators of coincidence events. Generators evenly gathering data sets of measured coincident quantum based variable. Evolution of such variable is examined by the tools of the TISEAN software package exploiting the approach of non-linear times series analysis.
Kvantová fyzika rozšiřuje způsoby, jak lze manipulovat s informací. Jedna z vlastností, která nemá v klasické fyzice analogii, a kterou tudíž nelze při práci s informací v klasických systémech využít, je kvantové provázání. Tuto vlastnost lze chápat jako určitý druh korelace mezi komponentami fyzikálního systému. Míra této korelace však není v klasických fyzikálních systémech dosažitelná. Za...
Ve své prezentaci se zmíním o vlivu hodnoty konstanty silné interakce na tvar spekter pozorovatelných veličin při studování vlastností protonových srážek, ve kterých se produkuje dva a více částicových spršek. Ukážu jak se tyto spektra pozorovatelných mění s hodnotou konstanty na příkladu simulovaných dat.
Charmed mesons serve as an excellent probe in the strongly interacting medium created during heavy ion collisions. This medium is called the quark-gluon plasma and it is an object of great interest due to its connection to the early stages of the Universe. The charmed mesons, such as the D$^\pm$, are created during the hard scattering part of the collision and therefore experience the entire...
One of the open questions in QCD today is the cause of the shadowing phenomenon
in nuclei. To understand this phenomenon it is necessary to study gluon distributions in
nuclei at small x. There are several models trying to describe such phenomenon in QCD
which have to be experimentally scrutinised and confirmed. One of the suitable processes
to investigate gluon distributions in nuclei is the...
Rydbergovské atomy jsou takové atomy, jejichž alespoň jeden elektron je excitován do vysokého kvantového stavu. Jejich doba života je extrémně dlouhá a vzhledem k tomu, že mají velký dipólový moment, jsou extrémně citlivé na působení externího pole, což se využívá především při manipulaci v takových polích. Experiment AEgIS, jemuž se věnuje první část práce, se v současné době zabývá výrobou...
co se do dějin fyziky nevešlo aneb jediná srozumitelná prezentace :)
In the first part of the talk we shall investigate how the averaging
over a large number of events influences the shape of the observed
correlation function. We demonstrate that a shape characterised by Levy
distribution may result from an average over Gaussian sources with
varying sizes and orientations. We then propose to sort the events
according to their similarity and investigate...
With the help of a master equation we study the evolution of the multiplicity distribution. Particularly we focus on the third and fourth factorial moments from which all other kinds of moments can be calculated.We first study how the third and the fourth moments thermalise when the kinetic temperature is fixed. Then we study the evolution of the moments in a situation with decreasing...
Measurements of open heavy flavour mesons can be used to study the proprieties of the, so called, quark-gluon plasma produced in heavy-ion (A+A) collisions. The STAR collaboration searches for differences in particle production between the A+A and p+p collisions via the nuclear modification factor. In the low-pt region, ${\rm D^{\pm}}$ mesons cannot be directly reconstructed with traditional...
In this presentation, we will give an introduction to the physics of heavy quarkonia in ultra-relativistic collisions of heavy nuclei. Different production-affecting phenomena will be overviewed and juxtaposed with experimental results of related observables. Furthermore, we will present recent measurements of the $\Upsilon$ production in Au+Au collisions at $\sqrt{s_\mathrm{NN}}=200$~GeV via...
$\Lambda_\mathrm{c}$ is the lightest baryon containing a charm quark and, as such, presents a unique probe into the bahavior of heavy quarks in the hot and dense QCD medium. Together with the measurement of the D$^0$ meson, we can probe the various modes of hadronization of the charm quark in heavy-ion collisions and bring more insight into the possible process of quark coalescense in the...
Cosmic ray particles undergo many changes during their propagation through the Universe including energy losses due to interactions with CMB or deflections in both galactic and extragalactic magnetic fields. Such effects make it much more difficult to identify some general cosmic ray properties and their original source. Results concerning the slope of the end of the cosmic ray energy spectrum...
The talk will give an overview of recent $B$-physics measurements at the ATLAS experiment, with a focus on the $CP$ violation in $B^0_s \rightarrow J/\psi(\mu^+\mu^−)\phi(K^+K^−)$ decay channel. In the Standard Model $CP$ violation is described by a phase in the CKM matrix. One of the manifestations of this complex phase is a phase shift between direct and mixing-mediated $B_s$ decays...
Complex phase in the CKM matrix describing quark mixing causes CP violation and can be studied in the decay $B^0_s \rightarrow J/\psi + \phi$. The determination of the initial flavour of neutral $B$ mesons can be inferred using information from the $B$ meson containing other pair-produced b-quark, reffered as opposite-side tagging. To study and calibrate the opposite-side tagging method,...
Last year, the D0 experiment announced the observation of narrow structure X(5568) in decay of B_s + \pi with almost 5 \sigma significance. This structure is investigated by the B-Physics Working group based on a data sample recorded with the ATLAS detector corresponding to 4.9 \fb^{-1} of pp collision data at 7 TeV and 19.5 \fb^{-1} at 8 TeV.
Evidence of the vector boson scattering (VBS) phenomena was discovered in Run 1
of the ATLAS detector at the LHC in the same sign WW production channel. Since
the detector acquire more and more data in Run 2, the phenomena starts to be
accessible also in the ZZ channel. This channel is very clean because of the
small background other than comming from QCD and provides a good opportunity...
Currently large $t\bar{t}$ production at the LHC allows detail study of the top quark, $t\bar{t}$quark pairs. The talk will instrodude the results of the analysis interested with the measurement of differential cross-section of high boosted $t$ quark and $t \bar{t}$ pairs as a function of various kinematic observables. Study is performed on the full datasets collected by the ATLAS detector at...
