Constraint on Lorentz invariance violation for spectral lag transition in GRB 160625B using profile likelihood

Shantanu Desai; Shalini Ganguly

doi:10.1140/epjc/s10052-025-14016-0

2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2025) 85: 290
https://doi.org/10.1140/epjc/s10052-025-14016-0

Regular Article - Experimental Physics

Constraint on Lorentz invariance violation for spectral lag transition in GRB 160625B using profile likelihood

Shantanu Desai¹^a and Shalini Ganguly²

¹ Department of Physics, IIT Hyderabad, 502284, Kandi, Telangana, India
² Department of Physics, St. Mary’s College of Maryland, 20686, St. Mary’s City, MD, USA

^a shntn05@gmail.com

Received: 29 November 2024
Accepted: 26 February 2025
Published online: 13 March 2025

Abstract

We reanalyze the spectral lag data for GRB 160625B using frequentist inference in order to constrain the energy scale $(E_{QG})$ $(E_{QG})$ of Lorentz Invariance Violation (LIV). For this purpose, we use profile likelihood to deal with the astrophysical nuisance parameters. This is in contrast to Bayesian inference implemented in previous works, where marginalization was carried out over the nuisance parameters. We show that with profile likelihood, we do not find a global minimum for $χ^{2}$ $\chi ^2$ as a function of $E_{QG}$ $E_{QG}$ below the Planck scale for both linear and quadratic models of LIV, whereas bounded credible intervals were previously obtained using Bayesian inference. Therefore, we can set one-sided lower limits in a straightforward manner. We find that $E_{QG} \geq 2.55 \times 10^{16}$ $E_{QG} \ge 2.55 \times 10^{16}$ GeV and $E_{QG} \geq 1.85 \times 10^{7}$ $E_{QG} \ge 1.85 \times 10^7$ GeV at 95% c.l., for linear and quadratic LIV, respectively. Therefore, this is the first proof-of-principles application of profile likelihood method to the analysis of GRB spectral lag data to constrain LIV.

© The Author(s) 2025

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.