29 MAY 2023
11:00 - 12:00

Abstract:

Cosmic muons are high-energy particles that constantly bombard the Earth's atmosphere from outer space. These particles are created by cosmic rays colliding with atoms in the upper atmosphere, and are capable of penetrating deep underground and through dense materials such as lead and concrete. This feature makes them an excellent tool for imaging and exploration. In this work we have brief review on the source of the cosmic muons and their properties, then we discuss their application in imaging and at the end we introduce an optimal detector that has been developed in IPM (Institute for Research in Fundamental Sciences) of Iran for imaging.

Based on:
https://doi:10.1088/1742-6596/1596/1/012008

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

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

25 MAY 2023
11:00 - 12:00

Abstract:

In this talk, I will first briefly review some quantities which are believed to be the gravity dual of quantum complexity. One of them is generalized volume-complexity which was recently introduced in [arXiv:2111.02429]. This quantity is an extension of volume in the Complexity=Volume (CV) proposal, by adding higher curvature corrections with a coupling constant "lambda" to the volume functional.

Next, I will talk about the calculation of generalized volume-complexity for two-sided Hyperscaling Violating (HV) black branes in "d+2" dimensions for different values of the hyperscaling violation exponent "theta" and dynamical exponent "z". It is observed that the generalized volume-complexity always grows linearly at late times, provided that we choose the coupling constant properly. Moreover, it approaches its late time value from below. I will also discuss the dependence of its growth rate on "d", "theta", "z" and "lambda".

At the end, I will report our results for the complexity of formation obtained from volume-complexity and show that it is not UV divergent. I will also discuss its dependence on the thermal entropy and temperature of the black brane.

This talk is based on:
arXiv: 2207.05287.


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

24 MAY 2023
11:00 - 12:00

Abstract:

In this talk, I present our last study in which we use the charged-current Higgs boson production process at future electron-proton colliders, with the subsequent decay of the Higgs boson into a $b\bar{b}$ pair, to probe the Standard Model effective field theory with dimension-six operators involving the Higgs boson and the bottom quark. The study is performed for two proposed future high-energy electron-proton colliders, the Large Hadron Electron Collider (LHeC) and the Future Circular Collider (FCC-he) at the center-of-mass energies of 1.3 TeV and 3.46 TeV, respectively. Constraints on the CP-even and CP-odd couplings are derived by analyzing the simulated signal and background samples. A realistic detector simulation is performed and a multivariate technique using the gradient Boosted Decision Trees algorithm is employed to discriminate the signal from background. Expected limits are obtained at $95\%$ Confidence Level for the LHeC and FCC-he assuming the integrated luminosities of 1, 2 and 10 $ab^{-1}$. We find that using 1 $ab^{-1}$ of data, the CP-even and CP-odd couplings can be constrained with accuracies of the order of $10^{-3}$ and $10^{-2}$, respectively, and a significant region of the unprobed parameter space becomes accessible.

Indico Link:
https://indico.hep.ipm.ir/e/r.jafari

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

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

22 MAY 2023
11:00 - 12:00

Abstract:

Upcoming searches for the stochastic background of inflationary gravitational waves (GWs) offer the exciting possibility to probe the evolution of our Universe prior to Big Bang nucleosynthesis. In this spirit, we explore the sensitivity of future GW observations to a broad class of beyond-the-Standard-Model scenarios that lead to a nonstandard expansion history. We consider a new scalar field whose coherent oscillations dominate the energy density of the Universe at very early times, resulting in a scalar era prior to the standard radiation-dominated era. The imprint of this scalar era on the primordial GW spectrum provides a means to probe well-motivated yet elusive models of particle physics. Our work highlights the complementarity of future GW observatories across the entire range of accessible frequencies.

Based on:
https://arxiv.org/abs/1904.07870

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

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

11 MAY 2023
11:00 - 12:00

Abstract:

In this talk, I give a brief introduction to holography with averaging on AdS3/CFT2 and mention some recent developments. I am going to review some important aspects of CFT2 and the analog of Virasora algebra on a CFT in comparison to any theory of gravity in AdS. After stating average holographic duality and some naive examples of that, I will review JT gravity in the context of holography with averaging to find out if there is an equality between a gravitational path integral and average over Hamiltonian of a quantum mechanical system.

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