9 MAR 2023
11:00 - 12:00

Abstract:

Chiral symmetry is an approximate symmetry of Quantum chromodynamics (QCD). At low temperatures and density, this symmetry is spontaneously broken. However, by increasing the temperatures or density, the chiral broken phase goes to the normal phase. Exploring the phase diagram of QCD is of fundamental interest. The aim is to understand the condensed matter, or many-body properties, of strong interaction. Heavy-ion collisions program aims to achieve this goal experimentally.
Recent observation on the spin polarization of Lambda particles indicates the matter produced at these collisions carries a large angular momentum. Moreover, since the colliding nuclei are charged particles we expect an enormous magnetic field to be generated at the early stage of collision. Studying the properties of matter under such extreme conditions give us some insight into the phase structure of quark matter.
In this talk, after providing a review on some general ideas as well as the heavy-ion collision program, I will present some of our latest results on the effect of rotation on the chiral symmetry breaking of a magnetized quark matter.

Meeting Place:
Seminar Room, School of Particles and Accelerators, IPM

6 MAR 2023
11:00 - 12:00

Abstract:

The Iranian Light Source Facility (ILSF) is a 3 GeV synchrotron radiation facility, which is in the design stage. The ILSF storage ring design is based on a five-bend achromat lattice providing an ultralow horizontal beam emittance of 0.27 nm-rad. Inevitable errors like imperfection of magnetic field and misalignment of magnets will introduce various destructive effects on the performance of the machine. The possibility of correcting the errors should be thoroughly examined before settling the design. In this paper, we have tried to estimate the errors as realistic as possible based on the results obtained from the simulation of the elements and the accuracy of the predicted equipment for fabrication and alignment. The influence of errors on the lattice is investigated. Closed orbit distortion, beta beating and betatron coupling are corrected and improvement made in the lattice functions and machine performance will be presented

Based on:
https://doi.org/10.1016/j.nima.2019.163180

Meeting Place:
Seminar Room, School of Particles and Accelerators, IPM

Link to Join Virtually:
https://meet.google.com/fnv-dfkk-ghb

2 MAR 2023
11:00 - 12:00

Abstract:

Spacetime wormholes can lead to surprises in black hole physics. We show that a very old black hole can tunnel to a white hole/firewall by emitting a large baby universe. We study the process for a perturbed thermofield double black hole in
Jackiw-Teitelboim (JT) gravity, using the lowest order (genus one) spacetime wormhole that corresponds to single baby-universe emission.

Meeting Place:
Seminar Room, School of Particles and Accelerators, IPM

1 MAR 2023
11:00 - 12:00

Abstract:

In this study, we present a new determination of the generalized parton distributions (GPDs) with their uncertainties at zero skewness, $\xi=0$, through a simultaneous analysis of all available experimental data of the nucleon electromagnetic form factors (FFs), nucleon charge and magnetic radii, proton axial FF (AFF), and wide-angle Compton scattering (WACS) cross section for the first time. This can be considered as the most comprehensive analysis of GPDs at $\xi=0$ performed so far. We show that such an analysis provides the simultaneous determination of three kinds of GPDs, namely $H^q$, $\tilde{H}^q$ and $E^q$, considering also the sea quark contributions. As a result, we find that the inclusion of the WACS and AFF data at larger values of the momentum transfer squared can put new constrains on GPDs and change them drastically in some cases. We also indicate that the results for the gravitational $FF$ $M_2$ and the proton total angular momentum $J^p$ calculated using the extracted GPDs are in more agreement with the light-cone QCD sum rules (LCSR) and lattice QCD predictions when all experimental data are included in the analysis simultaneously and the sea quark contributions are considered. This talk is based on arXiv:2211.09522 [hep-ph].

Indico Link
https://indico.hep.ipm.ir/e/m.goharipour

Meeting Place:
Seminar Room, School of Particles and Accelerators, IPM

Link to join virtually:
https://meet.google.com/fnv-dfkk-ghb

27 FEB 2023
11:00 - 12:00

Abstract:

In this research we want to consider TMD PDFs at small momentum fractions x. We want to show that the sea quark density and gluon density have "Fractal" or self-similar behavior at small value of x (approximate region of x<0.01). To this end, a Fractal-based parametrization for the sea quark density and gluon density would be proposed. The small x experimental datasets also should be included in this analysis.

Based on : ------

Meeting Place:
Seminar Room, School of Particles and Accelerators, IPM

Link to join virtually:
https://meet.google.com/fnv-dfkk-ghb