6 NOV 2024
11:00 - 12:00

Abstract:

The proton-radius puzzle refers to the discrepancy observed in measurements of the proton's charge radius when using different methods. This inconsistency has prompted extensive research and debate within the physics community, as it challenges the understanding of quantum electrodynamics and the fundamental properties of protons. In the present study, we determine the charge and magnetic radii of the proton and neutron through a global analysis of the generalized parton distributions (GPDs) at zero skewness for the first time. Our results challenge the measurements or analyses in which the nucleon's radii are extracted considering just a particular experiment or observable, or using only data points covering particular kinematic regions. We emphasize that simultaneous analysis of all available experimental data related to the radii of the nucleons would be preferable to determine their exact values.
The final results obtained from our analysis by this way are: rpE=0.8558±0.0135 fm, rpM=0.8268±0.0533 fm, =−0.1181±0.0270 fm2, and rnM=0.8367±0.0845 fm.

Indico Link:
https://indico.hep.ipm.ir/e/m.goharipour1

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

Link to Join Virtually:
https://meet.google.com/bda-vsem-tuv

6 NOV 2024
14:00 - 15:00

The connection between excluding complete graphs (for various notions of exclusion) and the chromatic number of graphs is nearly a century old. In the 1940s, Hadwiger conjectured that a graph with no $K_n$-minor is $(n-1)$-colorable. Later, in the 1950s, Hajos proposed a strengthening of this conjecture, that every graph containing no subdivision of $K_n$ as a subgraph, is $(n-1)$-colorable. While both conjectures remain unresolved in some cases, a bound $c=c(n)$ (instead of $n-1$) for the chromatic number is known for every $n$ for both conjectures.
A natural attempt to strengthen this result would be to ask whether there exists a constant $c=c(n)$ such that every graph with no subdivision of $K_n$ as an induced subgraph is $c$-colorable. This question is a special case of Scott's conjecture from the 1990s. It was not until 2012 that the first non-trivial case, for $n=4$, was solved by Lev^eque, Maffray, and Trotignon.
In this talk, we present the solution to conjecture for $ngeq 5$ and describe the techniques used to achieve this result. This talk is based on joint works with Nicolas Trotignon, particularly the following: arXiv:2112.11970.

Zoom room information:
https://us06web.zoom.us/j/85237260136?pwd=MFSZoKdmRXAjfaSaBzbf19lTaaKglf.1
Meeting ID: 852 3726 0136
Passcode: 362880
Venue: Niavaran, Lecture Hall 1

5 NOV 2024
14:00 - 15:00

Date and time

Tuesday, November 5th, 2024 (Aban 15th, 1403), 2:00 pm (Tehran zone)





Link

https://www.skyroom.online/ch/schoolofphysics/highenergyseminar



Abstract
The proton-radius puzzle refers to the discrepancy observed in measurements of the proton's charge radius when using different methods. This inconsistency has prompted extensive research and debate within the physics community, as it challenges the understanding of quantum electrodynamics and the fundamental properties of protons. In the present study, we determine the charge and magnetic radii of the proton and neutron through a global analysis of the generalized parton distributions (GPDs) at zero skewness for the first time. Our results challenge the measurements or analyses in which the nucleon's radii are extracted considering just a particular experiment or observable, or using only data points covering particular kinematic regions. We emphasize that simultaneous analysis of all available experimental data related to the radii of the nucleons would be preferable to determine their exact values. The final results obtained from our analysis by this way are: rpE=0.8558±0.0135 fm, rpM=0.8268±0.0533 fm, ⟨r2nE⟩=−0.1181±0.0270 fm2, and rnM=0.8367±0.0845 fm.

5 NOV 2024
09:00 - 15:00

PsychoPhysics - Workshop

5 NOV 2024
09:00 - 15:00


Neural Data Analysis - Workshop

4 NOV 2024
16:00 - 18:00

Statistical evidence, Normic Support, and Rationality

4 NOV 2024
11:00 - 12:00

Abstract:

In the CMS Phase-2 Upgrade of the RPC Link System, the legacy electronics will be replaced with advanced systems designed to enhance data acquisition from RPC detectors. This upgrade will improve the timing resolution for data taking from 25 ns to an impressive 1.5 ns. However, with the anticipated significant increase in luminosity during the next run in 2028, the interactions of high-energy particles with the link system's electronics are expected to rise dramatically. This surge in luminosity will result in more collisions and, consequently, a substantial increase in the volume of generated data. To address these challenges, both new hardware and effective strategies to mitigate the impact of these collisions—particularly in FPGAs, which serve as the core processing units—are essential. In this presentation, we will introduce the new data acquisition system within the CMS project and provide an overview of key components of the firmware implemented in the FPGA to achieve these objectives.

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

Link to Join Virtually:
https://www.skyroom.online/ch/ipm-particles/journal-club

31 OCT 2024
14:00 - 16:00

In this talk we provide a complete axiomatization of the Provability Logic for Heyting Arithmetic HA (this is the first-order intuitionistic fragment of the Peano Arithmetic PA). It turns out that the provability logic of HA is equal to iGL (intuitionistic fragment of the Gödel-Löb logic GL) plus ◻A → ◻B for some admissible rules A/B of iGL. Then we describe a crucial tool which was helpful during the completeness proof: a new Kripke style semantic for intuitionistic modal logics, called mixed semantics, which is a combination of derivability and usual validity in Kripke models.
This talk is based on the following two manuscripts: [1, 2].
[1] Mojtaba Mojtahedi. On provability logic of HA, 2022. https://arxiv.org/abs/ 2206.00445.
[2] Mojtaba Mojtahedi. Relative unification in intuitionistic logic: Towards provability logic of HA, 2022. https://arxiv.org/abs/2206.00446.

Zoom room information:
https://us06web.zoom.us/j/81916335336?pwd=5zQT4lutMiBoY5 Xp1pkFGtbqiaGozg.1
Meeting ID: 819 1633 5336
Passcode: 559618
Venue: Niavaran, Lecture Hall 1

30 OCT 2024
14:00 - 15:00

Shape memory alloys (SMAs) are highly desirable for widespread utilization in biomedical implants and micro electro-mechanical systems (MEMS) due to their distinctive property of undergoing reversible martensitic phase transformation, which can be triggered either thermally or mechanically. However, the functionality of SMAs is a crucial property affecting the exploitation of these smart materials. Normally, their tensile reversibility degrades significantly within first a few cycles and is declined at smaller scales. Here, we studied the small-scale tensile superelasticity of a Cu-based shape memory alloy upon cycling. The tensile single-crystalline micro-samples were fabricated by the focused ion beam milling process. Due to the stress-induced martensitic transformation, the superelastic behavior of the micro-samples was investigated by in-situ micro-tension during large number of cycles followed by monitoring microstructural evolution upon cycling. The highly cycled micro-samples still exhibited a perfectly reproducible and completely recoverable superelastic behavior. To assist theoretical analysis of deformation, the orientation of the samples and crystal structure of austenite and martensite were also measured by electron-backscatter diffraction (EBSD) and synchrotron X-ray microdiffraction experiment, respectively.


Click the link to join this webinar


https://www.skyroom.online/ch/schoolofnanoscience/weeklyseminars