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## Aktualności

# Blogi

Dear All,

We have the pleasure of inviting you to the Particle Theory Seminar on Tuesday, November 14 at 12:15, which will be given by

Farid Taghinavaz (School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), Tehran, Iran)

entitled

„Relativistic hydrodynamics with phase transitions".

Abstact:

It has been confirmed by many observations that the Quark-Gluon plasma is a new type of matter that is produced after the collisions of heavy ions and in today’s energies it behaves like (almost) perfect fluid. The relativistic hydrodynamics (RH) is an appropriate tool to describe the dynamics of this complicated system near the local equilibrium or even far from equilibrium. However, there has been several unsolved issues by using the RH which one of them is how to employ it or in what extent the RH is valid near the phase transition points. We benefit of the gauge/gravity duality to study the time-dependent perturbations of the dual metric in a short-wave-length limit at a certain phenomenological model, the so called Einstein-Klein-Gordon model. We will examine the radius of convergence of the hydro series near the critical points for various kinds of phase transitions as well as different spin-sectors.

The speaker will be on-site, local participants are invited to meet in the seminar room D-2-02.

Piotr Korcyl, Jacek Wosiek, Michał Praszałowicz

Dear All,

We have the pleasure of inviting you to the Particle Theory Seminar on Tuesday, November 7 at 12:15, which will be given by

Maxim Nefedov (Universite Paris-Saclay, CNRS)

entitled

„ Curing high-energy instability of quarkonium production cross sections with High-Energy Factorisation".

The speaker will be online, local participants are invited to meet in the seminar room D-2-02.

Dear All,

We have the pleasure to invite you to the Particle Theory Seminar on Tuesday, October 24 at 12:15, which will be given by

James Whitehead (IFJ PAN)

entitled

„The KrkNLO method for NLO parton shower matching".

Abstract:

'Matched' calculations combining the next-to-leading-order (NLO) accuracy of perturbative QCD with the logarithmic resummation of a parton shower are a key workhorse driving LHC phenomenology in the precision era. The KrkNLO method for NLO parton shower matching uses multiplicative reweighting and a convenient choice of PDF factorisation scheme to produce matched NLO + parton shower predictions. By construction, it guarantees positive weights. I will present an introduction to the theory of NLO matching, an overview of the KrkNLO method, and phenomenological results from the implementation of new processes in Herwig 7.

The seminar will be in in-person mode in the seminar room D-2-02, but you can also attend remotely through Zoom.

Piotr Korcyl, Jacek Wosiek, Michał Praszałowicz

Dear All,

We have the pleasure to invite you to the Particle Theory Seminar on Tuesday, October 17 at 12:15, which will be given by

Yizhuang Liu (IFT UJ)

entitled

„ A survey of the heavy-light Sudakov universality class".

The seminar will be in in-person mode in the seminar room D-2-02, but you can also attend remotely through Zoom:

Piotr Korcyl, Jacek Wosiek, Michał Praszałowicz

Dear All,

We have the pleasure to invite you to the Particle Theory Seminar (together with the Field Theory Department) on Tuesday, October 10 at 14:00 (different time!), which will be given by

Błażej Ruba (University of Copenhagen)

entitled

„Dense and strongly interacting nonrelativistic fermions".

Abstract:

I will discuss estimates of the ground state energy of interacting nonrelativistic fermions obtained using an approximate bosonization method. The new result concerns the strongly coupled regime, which I will compare to the perturbative regime and the critical scaling conventionally called "mean field".

The seminar will be in in-person mode in the seminar room D-2-02, but you can also attend remotely through Zoom:

Piotr Korcyl, Jacek Wosiek, Michał Praszałowicz

Dear All,

We have the pleasure to invite you to the Particle Theory Seminar on Tuesday, October 3 at 12:15, which will be given by

Steven Bass (CERN)

entitled

„ Cosmology with an emergent particle physics Standard Model“.

The seminar will be in in-person mode in the seminar room D-2-02, but you can also attend remotely through Zoom.

Dear All,

We have the pleasure to invite you to the Particle Theory Seminar on Tuesday, July 4 at 12:15, which will be given by

Asaad Daher (IFJ PAN)

entitled

„Entropy production in spin hydrodynamics“.

The seminar will be in only in in-person mode in the seminar room D-2-02.

Piotr Korcyl, Jacek Wosiek, Michał Praszałowicz

Dear All,

We have the pleasure to invite you to the Particle Theory Seminar on Tuesday, June 20 at 12:15, which will be given by

Kiminad Mamo (Argonne National Laboratory)

entitled

„Quark and gluon GPDs at finite skewness from strings in holographic QCD“.

Abstract:

In this talk, we present a comprehensive framework for constructing Generalized Parton Distributions (GPDs) by employing holographic QCD in the context of the large Nc limit. The emphasis is on the low-x and finite skewness regimes. Our methodology involves using t-channel string exchanges in soft-wall AdS to extract the spin-j conformal (Gegenbauer) moments of GPDs from the holographic amplitudes associated with exclusive electroproduction processes. These moments are then evolved to higher resolution scales using QCD evolution equations. We demonstrate the applicability of our evolved GPDs (reconstructed from their evolved conformal moments) in the analysis of electroproduction involving neutral rho, phi,and charged rho mesons. Non-perturbative contributions in the s+u channel are also accounted for using holographic QCD, and our findings show good agreement with existing experimental data. Our GPDs offer valuable insights into partonic distributions and serve as a useful resource for future experimental investigations and global data analyses.

The seminar will be in a hybrid mode, local people are invited to meet in the seminar room D-2-02.

Piotr Korcyl, Jacek Wosiek, Michał Praszałowicz

Dear All,

We have the pleasure to invite you to the Particle Theory Seminar on Tuesday, June 13 at 12:15, which will be given by

Francesco Giacosa (Jan Kochanowski University in Kielce)

entitled

„Neutrino mixing in the interaction picture“.

The seminar will be in a hybrid mode, local people are invited to meet in the seminar room D-2-02.

Piotr Korcyl, Jacek Wosiek, Michał Praszałowicz

Dear All,

We have the pleasure to invite you to the Particle Theory Seminar on Tuesday, June 6 at 12:15, which will be given by

Andrea Bulgarelli (University of Torino)

entitled

„ Entanglement entropy from non-equilibrium lattice simulations“

Abstract:

“The entanglement entropy is a quantity encoding important features of strongly interacting quantum many-body systems and gauge theories, but its analytical study is still limited to systems with high level of symmetry. This motivates the search for efficient techniques to investigate this quantity numerically, by means of Monte Carlo calculations on the lattice. In this talk, we present a lattice determination of the entropic c-function using a novel algorithm based on Jarzynski's equality: an exact theorem from nonequilibrium statistical mechanics. After presenting benchmark results for the Ising model in two dimensions, where our algorithm successfully reproduces the analytical predictions from conformal field theory, we discuss its generalization to the three dimensional Ising model, for which we were able to extract universal terms beyond the area law. Finally we comment on future applications.”

The seminar will be in a hybrid mode, local people are invited to meet in the seminar room D-2-02.

Piotr Korcyl, Jacek Wosiek, Michał Praszałowicz

Dear All,

we have the pleasure to invite you to the Particle Theory Seminar on Tuesday, May 30 at 12:15, which will be given by

Maciej Majka, Marcin Zagórski (IFT UJ)

entitled

„ Formation of gene expression patterns in biological systems “

Abstract:

“The development of multicellular organisms is a dynamic process in which cells divide, rearrange, and interpret molecular signals to adopt specific cell fates. This results in the emergence of gene expression patterns, that later on give raise to different body parts and organs. We still lack full understanding of how these patterns could form and remain stable during organism development. In this talk we address this question by considering reaction-diffusion model with two genes interacting via diffusible signaling molecules, controlling the size of their own source regions. By identifying the conservation law describing the number of particles reaching the front of the activated expression domain, we derive a range of analytical results. In particular, we observe the phase transition between patterns with expanding contact zone and patterns with contact zone of a well-defined size. Further, we provide exact conditions ensuring pattern stability. Finally, we classify two-gene regulatory motifs found in biological systems into classes resulting in different stability regimes.”

The seminar will be in a hybrid mode, local people are invited to meet in the seminar room D-2-02.

Piotr Korcyl, Jacek Wosiek, Michał Praszałowicz

Dear All,

we have the pleasure to invite you to the Particle Theory Seminar on Tuesday, April 25 at 12:15, which will be given by

Marcus Niechciol (University of Siegen)

entitled

„Violations of Lorentz Invariance and Their Connections to Cosmic Particles“

Abstract:

“Lorentz invariance, i.e., the notion that the laws of physics should stay the same regardless of how an observer moves, is one of the pillars of modern physics. Yet, current efforts to construct a more fundamental theory beyond the standard model of particle physics open up a small window for violations of Lorentz invariance. Cosmic particles offer unique possibilities to search for such violations and thus test Lorentz invariance at energy scales far beyond the reach of man-made particle accelerators. Focussing on one specific theory framework, the talk will discuss how bounds on Lorentz violation within this framework have been obtained from measurements of cosmic particles by looking for processes that are forbidden in the conventional, Lorentz-invariant theory, but become allowed when Lorentz invariance is broken. In addition, a novel ansatz based on the extensive air showers initiated by cosmic particles in the Earth’s atmosphere will be presented. Using this approach, the bounds on Lorentz violation have been improved by several orders of magnitude.”

The seminar will be in a hybrid mode, local people are invited to meet in the seminar room D-2-02.

Piotr Korcyl, Jacek Wosiek, Michał Praszałowicz

Dear All,

we have the pleasure to invite you to the Particle Theory Seminar on Tuesday, April 18 at 12:15, which will be given by

Wojciech Florkowski (IFT UJ)

entitled

" Spin hydrodynamics and pseudogauge transformations”

Abstract:

"Several recent approaches to relativistic hydrodynamics of particles with spin ½ will be shortly reviewed. A possible explanation of the (in)sensitivity of the obtained results to the so called pseudogauge transformation will be offered."

The seminar will be in a hybrid mode, local people are invited to meet in the seminar room D-2-02.

Piotr Korcyl, Jacek Wosiek, Michał Praszałowicz

Dear All,

we have the pleasure to invite you to the Particle Theory Seminar on Tuesday, April 4 at 12:15, which will be given by

Piotr Korcyl (IFT UJ)

entitled

"Recent progress in Monte Carlo simulations enhanced with machine learning techniques”

Abstract:

"Several ways of incorporating machine learning techniques into Monte Carlo algorithms have been proposed in the last couple of years. After a brief introduction, I will summarize the progress of our group in this direction concentrating on the use of autoregressive neural networks in simulations of discrete statistical systems. I will also discuss future prospects of these methods in particle physics."

The seminar will be in a hybrid mode, local people are invited to meet in the seminar room D-2-02.

Piotr Korcyl, Jacek Wosiek, Michał Praszałowicz

Dear All,

we have the pleasure to invite you to the Particle Theory Seminar on Tuesday, March 28 at 12:15, which will be given by

Paweł Sznajder (NCBJ)

entitled

"Machine learning techniques in phenomenology of generalised parton distributions (GPDs)”

Abstract:

"Generalised partons distributions (GPDs) describe the internal structure of hadrons in terms of quarks and gluons. They can be used, for instance, to study so-called nucleon tomography, and to access elements of the QCD energy-momentum tensor. Reconstruction of GPDs is a particularly difficult task, as available data are sparse compared to the number of objects and dimensions one must consider. In addition, one needs to solve a difficult inverse problem and fulfil a set of not trivial theory-driven constraints. In my talk I will show how elements of machine learning can be adapted and used for these purposes. I will focus on artificial neural networks, stressing their complementarity to classic techniques, like parametric fits. Technicalities involving e.g. genetic algorithms will also be described. "

The seminar will be in a hybrid mode, local people are invited to meet in the seminar room D-2-02.

Piotr Korcyl, Jacek Wosiek, Michał Praszałowicz

Dear All,

we have the pleasure to invite you to the Particle Theory Seminar on Tuesday, March 21 at 12:15, which will be given by

Gergely Marko (University of Bielefeld)

entitled

"Electric susceptibility of the strongly interacting plasma"

Abstract:

"The response of strongly interacting matter to a background magnetic field is well understood by now thanks to first principles lattice QCD studies. The introduction of an electric field, however, suffers from a sign problem in Monte Carlo simulations, while also raising questions on the definiteness of a thermal equilibrium in general. As a first step towards lattice simulations for the electric susceptibility of QCD, we study the leading response of hot quark matter to external electric fields using a perturbative expansion in equilibrium thermal field theory. We discuss the specifics of the equilibrium state in the presence of the external electric field and calculate the susceptibility in a small field expansion. In comparison we also brush up the evaluation of the effective action in constant electric backgrounds using Schwinger's exact propagator obtained as one of the earliest results in the worldline formalism. We point out that the two approaches lead to different results, and discuss the origin of the difference."

The seminar will be in a hybrid mode, local people are invited to meet in the seminar room D-2-02.

Piotr Korcyl, Jacek Wosiek, Michał Praszałowicz

Dear All,

we have the pleasure to invite you to the Particle Theory Seminar on Tuesday, March 14 at 12:15, which will be given by

Krzysztof Cichy (UAM)

entitled

"Probing nucleon's 3D structure with Lattice QCD"

Abstract:

"Large momentum effective theory relates lattice-calculable non-local correlations of boosted nucleon states to light-front partonic distributions. An example of such functions are generalized parton distributions (GPDs), which describe the spatial distributions of partons in the transverse plane. Until recently, a practical obstacle for computing GPDs was the need to perform separate calculations for every momentum transfer vector, required in the standard symmetric (Breit) frame of reference. Last year, we developed a new method based on parametrization of the relevant matrix elements in terms of Lorentz-invariant amplitudes. This allows one to extract GPDs in an efficient manner from asymmetric frames, by grouping calculations for several momentum transfers in a single lattice calculation. I will discuss the most recent progress in this field and discuss its further prospects."

The seminar will be in a hybrid mode, local people are invited to meet in the seminar room D-2-02.

Piotr Korcyl, Jacek Wosiek, Michał Praszałowicz

Dear All,

we have the pleasure to invite you to the Particle Theory Seminar on Tuesday, March 7 at 12:15, which will be given by

Sándor Lökös (IFJ PAN)

entitled

"On the shape of the Bose-Einstein correlation function"

Abstract:

" Quantum statistical correlations were discovered by Hanbury Brown and Twiss by studying astrophysical objects in 1956. Later, the phenomena was also observed in high energy physics by Goldhaber, Goldhaber, Lee and Pais. The correlation function can be linked to the geometrical size of the source; that feature allowed astrophysicist to determine angular diameter of stars and it allows to perform investigation on the femtometer scale in high energy reactions. Hence the field usually refered as femtoscopy, however, the term was coined much later than the discovery. Precise measurements of the shape of such correlation functions revealed that the usually assumed Gaussian source shape is insufficient to describe the data and a more general source distribution should be considered, i.e., the Levy-stable distributions. The shape of the correlation functions is important not only because of its power of mapping the spatio-temporal structure of the emitting source on the femtometer scale but the detailed investigation could reveal underlying processes like partially coherent particle production, in-medium mass modifications or could give us information about the QCD phase diagram. In my presentation I will discuss the theoretical basis of the HBT analyses and give an exhaustive overview of recent experimental results from RHIC and LHC."

The seminar will be in a hybrid mode, local people are invited to meet in the seminar room D-2-02.

Piotr Korcyl, Jacek Wosiek, Michał Praszałowicz

Dear All,

we have the pleasure to invite you to the Particle Theory Seminar on Tuesday, February 28 at 12:15, which will be given by

Nikodem Witkowski (IFT UJ)

entitled

"Coalescence model of deuteron production"

Abstract:

"Coalescence model describes production of light nuclei in hydro-inspired thermal model. After introducing the theory of thermal model and coalescence two approaches to the system symmetry were introduced. Within both regimes adequate model were developed and their predictions were compared to the experimental data. "

The seminar will be in a hybrid mode, local people are invited to meet in the seminar room D-2-02.

Piotr Korcyl, Jacek Wosiek, Michał Praszałowicz