arXiv subjects

Dhruv Ringe

Publications and source records attributed to Dhruv Ringe.

4 recordsLinked to original sources

arXiv2025

Constraining particle physics models with gravitational waves from the early universe

In this Ph.D. thesis, we study the methods to constrain particle physics models using the stochastic GW imprints from cosmological phase transitions (PTs). Beginning with the theory and background, we describe how the GW background from first-order PTs (FOPTs) and topological defects such as domain walls (DWs) can constrain the model parameter space at upcoming GW observatories. The first BSM scenario involves a flavon FOPT in two ultraviolet-complete models of the Froggatt-Nielsen (FN) mechanism. In both models, for the FN symmetry-breaking scale $v_s = 10^{4-7}\,$GeV, the parameter space is constrained by GWs in upcoming observatories such as BBO, DECIGO, CE, and ET. However, the GW spectrum does not discriminate between the two models. Next, we consider FOPT in the doublet left-right symmetric model (DLRSM) during $SU(2)_R\times U(1)_{B-L}$ breaking. For the breaking scale $v_R=20,\,30,\,50\,$TeV, the parameter space can be constrained by GW observations at BBO, FP-DECIGO, and Ultimate DECIGO. A large number of points with detectable GW signals can be ruled out from the precise measurement of the trilinear Higgs coupling at future colliders. Finally, we discuss the GW spectrum generated by DWs formed after the spontaneous breaking of the discrete $\mathcal{P}$-symmetry imposed on DLRSM. Using Bayesian analysis, we fit the 15-year NANOGrav dataset to the GW spectrum from DWs in DLRSM and determine the best-fit values of the DW surface tension and the bias potential. The techniques of this thesis can be applied to other BSM scenarios in the future.

hep-ph↗

arXiv2024

Domain wall constraints on the doublet left-right symmetric model from pulsar timing array data

Recent evidence of a stochastic gravitational wave (GW) background found by NANOGrav and other pulsar timing array (PTA) collaborations has inspired many studies looking for possible sources. We consider the hypothesis that the GW signature is produced by domain walls (DWs) arising in the doublet left-right symmetric model (DLRSM) due to the spontaneous breaking of the discrete parity symmetry. The DW network consists of two types of DWs, namely $Z_2$ and $LR$ DWs, which have different surface tensions. We find kink solutions for both types of DWs and obtain the parametric dependence of the surface tension. Considering the GW signal from the DLRSM DW model with and without the contribution from supermassive black hole binaries, we perform a Bayesian analysis using the PTA data to estimate the posterior distribution and identify best-fit parameter ranges. The PTA data favors a parity-breaking scale of $\mathcal{O}(10^5)$\,GeV, and a biased potential $V_{\rm{bias}}\sim (\mathcal{O}(100)\,\rm{MeV})^4$. The model with only DLRSM DWs is slightly favored over the model where additional SMBHB contribution is considered.

hep-ph↗

arXiv2024

Gravitational Wave imprints of the Doublet Left-Right Symmetric Model

We study the gravitational wave (GW) signature in the doublet left-right symmetric model (DLRSM) resulting from the strong first-order phase transition (SFOPT) associated with $SU(2)_R\times U(1)_{B-L}$-breaking. For different values of the symmetry-breaking scale $v_R =20,~30$, and $50$ TeV, we construct the one-loop finite temperature effective potential to explore the parameter space for regions showing SFOPT. We identify the region where the associated stochastic GW background is strong enough to be detected at planned GW observatories. A strong GW background favors a relatively light neutral CP-even scalar $H_{3}$, arising from the $SU(2)_R$ doublet. The $SU(2)_L$ subgroup of DLRSM is broken by three vevs: $κ_1,~κ_2$, and $v_L$. We observe a preference for $\mathcal{O}(1)$ values of the ratio $w=v_L/κ_1$, but no clear preference for the ratio $r=κ_2/κ_1$. A large number of points with strong GW background can be ruled out from precise measurement of the trilinear Higgs coupling and searches for $H_3$ at future colliders.

hep-ph↗

arXiv2022

Probing intermediate scale Froggatt-Nielsen models at future gravitational wave observatories

The flavor symmetry-breaking scale in the Froggatt-Nielsen (FN) mechanism is very weakly constrained by present experiments, and can lie anywhere from a few TeV to the Planck scale. We construct two minimal, non-supersymmetric, ultraviolet (UV) complete models that generate the FN mechanism, with a global $U(1)_{\rm{FN}}$ flavor symmetry and a single flavon field. Using the one-loop finite temperature effective potential, we explore the possibility of a strong first order phase transition (SFOPT) induced by the flavon. We show that if the flavor symmetry-breaking occurs at intermediate scales $\sim 10^4-10^7$ GeV, then in certain regions of the parameter space, the associated stochastic gravitational wave (GW) background is strong enough to be detected by second generation GW observatories such as the Big Bang Observer (BBO), the Deci-hertz interferometer Gravitational Observatory (DECIGO), the Cosmic Explorer (CE) and the Einstein Telescope (ET). We identify viable regions of the parameter space for the best detection prospects. While both models of flavor can produce a detectable GW background, the GW signature cannot be used to discriminate between them.

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