## Journal Club

Seminar Room

If you want to propose a paper, you can contact **Supratim Das Bakshi** (*sdb AT ugr.es*)

### Tuesday 14th of March, 2023

**Title: ****Beta functions and anomalous dimensions up to three loops**

Abstract: We derive an algorithm for automatic calculation of perturbative beta functions and anomalous dimensions in any local quantum field theory with canonical kinetic terms. The infrared rearrangement is performed by introducing a common mass parameter in all the propagator denominators. We provide a set of explicit formulae for all the necessary scalar integrals up to three loops.

Presented by Javi Fuentes

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**Title: ****Possible Relation between the Cosmological Constant and Standard Model Parameters**

Abstract: We propose possible properties of quantum gravity in de Sitter space, and find that they relate the value of the cosmological constant to parameters of the Standard Model. In de Sitter space we suggest (i) that the most sharply defined observables are obtained by scattering objects from the horizon and back to the horizon and (ii) that black holes of discrete charge are well defined states in the theory. For a black hole of minimal discrete electric charge, we therefore demand that a scattering process involving the black hole and a probe can take place within a Hubble time before evaporating away, so that the state of a discretely charged black hole is well defined. By imposing that the black hole's charge is in principle detectable, which involves appreciably altering the state of a scattered electron, we derive a relation between the Hubble scale, or cosmological constant, and the electron's mass and charge and order one coefficients that describe our ignorance of the full microscopic theory. This gives the prediction Λ∼ 10^−123±2 Mpl, which includes the observed value of dark energy. We suggest possible ways to test this proposal.

Presented by José Maria

#### All Dates

- 2024
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