arXiv subjects

Akshat Khanna

Publications and source records attributed to Akshat Khanna.

8 recordsLinked to original sources

arXiv2026

Explaining 650 GeV and 95 GeV Anomalies in the 2-Higgs Doublet Model Type-I

We propose an interpretation of a rather significant 650 GeV excess emerged at the Large Hadron Collider (LHC) from CMS Collaboration data in the $γγb\bar b$ final state, accompanied by further clusters at 125(90-100) GeV in the $γγ(b\bar b)$ system, within the 2-Higgs Doublet Model Type-I (2HDM-I) in presence of a softly broken $\mathcal{Z}_{2}$ symmetry. The underlying process that we probe is $gg$-initiated production of a CP-odd (or pseudoscalar) Higgs boson $A$, with mass around 650 GeV, decaying into the Standard Model (SM)-like Higgs state $H$ (decaying into $γγ$) and a $Z$ boson (decaying into $b\bar b$). We configure this theoretical framework so as to also have in the spectrum a light CP-even (or scalar) Higgs state $h$ with mass around 95 GeV, which is included for the purpose of simultaneously explaining additional data anomalies seen in the $b\bar b$, $γγ$ and $τ^+τ^-$ final states while searching for light Higgs states at the Large Electron-Positron (LEP) collider (the first one) and LHC (the last two). By accounting for both experimental and theoretical constraints, our results show that the 2HDM-I can explain all aforementioned anomalies at a significance level of $2.5 σ$.

hep-ph↗

arXiv2026

ILC Phenomenology of the $Z_3$ symmetric Type-Z Three Higgs Doublet Model

The Three-Higgs-Doublet Model (3HDM) extends the Standard Model by introducing two additional scalar doublets, leading to a rich spectrum of new particles: three neutral CP-even Higgs bosons ($h_1$, $H_2$, $H_3$), two neutral CP-odd Higgs bosons ($A_2$, $A_3$), and two charged Higgs bosons ($H_2^+$, $H_3^+$). In this work, we present a phenomenological study of the 3HDM at the future International Linear Collider (ILC) with a center-of-mass energy of $\sqrt{s} = 1000\,\text{GeV}$. Applying a comprehensive set of theoretical and experimental constraints, we identify promising new physics signals with sufficiently large production cross-sections. Our analysis shows that $e^+e^- \to H_2 A_2$, $e^+e^- \to H_2 H_2 Z$, $A_2 A_2 Z$, $H_2 H_2^{\pm} W^{\mp}$, $A_2 H_2^{\pm} W^{\mp}$ and $H_1 H_2 A_2$ are among the most sensitive channels to probe this extended Higgs sector. We demonstrate that a future ILC would offer a powerful platform to test these interactions and discover these heavier Higgs bosons thus providing evidence of physics beyond the Standard Model.

hep-ph↗

arXiv2026

Neutral Scalar Signatures at a Muon Collider in the $Z_3$ symmetric Three Higgs Doublet Model

Extending the scalar sector of the Standard Model is a well-motivated approach to exploring physics beyond the Standard Model. In this work, we investigate the phenomenology of the Three Higgs Doublet Model at a future muon collider. The scalar spectrum of the 3HDM comprises three CP-even Higgs bosons, two CP-odd Higgs bosons, and a pair of charged Higgs states. Focusing on Higgs pair production via muon-antimuon annihilation, we study the production and decay of neutral scalar states through the process $μ^+μ^- \to ϕ_i ϕ_j$, assuming a mass hierarchy in which the SM-like CP-even Higgs is the lightest state. We analyze several benchmark scenarios leading to $b\bar{b}b\bar{b}$ and $b\bar{b}t\bar{t}$ final states, and perform a cut-and-count analysis at a center-of-mass energy of $\sqrt{s}=3$ TeV. Our results demonstrate that a future muon collider provides a sensitive and promising environment to probe extended Higgs sectors, with neutral scalar states in the mass range of $200-400$ GeV being discoverable with $5σ$ significance for integrated luminosities of $\mathcal{O}(1-4 \ \mathrm{ab}^{-1})$.

hep-ph↗

arXiv2026

Flavour-Changing Neutral Current Top Decays in the Three Higgs Doublet Model

We study flavour-changing neutral current decays of the top quark in the democratic Three Higgs Doublet Model featuring a $Z_3$-symmetric scalar potential and Natural Flavour Conservation. In this framework, while such processes are absent at tree-level, the extended scalar sector induces new one-loop contributions to rare top decays. We compute the branching ratios for processes of the form $t \to q X$ (with $q = u, c$ and $X$ denoting a boson of the model), and explore the viable regions of the parameter space under theoretical consistency conditions and current experimental constraints. Several alignment-limit scenarios corresponding to different hierarchies among the CP-even Higgs states are analysed, and we find that the predicted branching ratios can significantly exceed their Standard Model expectations while remaining consistent with existing limits. In particular, we identify scenarios with light non-standard scalars that can lead to rates within the projected sensitivity of the High-Luminosity LHC. Our results therefore highlight rare top decays as a promising probe of the extended scalar sector of the Three Higgs Doublet Model.

hep-ph↗

arXiv2026

LHC Signatures of Neutral Scalar Cascades in the $Z_3$ symmetric 3HDM

Extending the scalar sector is one of the standard approaches to exploring scenarios beyond the Standard Model. In this work, we examine the collider phenomenology of the Three Higgs Doublet Model (3HDM) in the Type-Z or the democratic Yukawa interaction setup at the LHC. The scalar spectrum of the 3HDM includes three CP-even scalars, two CP-odd scalars, and four charged Higgs bosons. Focusing on cascade decay topologies, we investigate the collider signatures of the neutral scalars through the process $pp \rightarrow SV$, where $S$ is a neutral scalar and $V$ is a vector boson. We perform a cross-section analysis across multiple benchmark points that satisfy both theoretical and experimental constraints, considering two mass hierarchy scenarios: (i) Regular Hierarchy, where the SM-like Higgs is the lightest CP-even scalar, and (ii) Medial Hierarchy, featuring one Higgs boson lighter than the SM Higgs and one heavier. For both scenarios, we study the specific process $pp \rightarrow A \rightarrow HZ \rightarrow b \bar{b} l^+l^-$, performing a cut and count analysis at $\sqrt{s}=14$ TeV. Our results demonstrate that while the Medial Hierarchy scenario allows discovery-level sensitivity for both the CP-even and CP-odd scalars, achieving the same sensitivity in the Regular Hierarchy setup necessitates substantially higher luminosity.

hep-ph↗

arXiv2025

Explaining 95 GeV Anomalies in the 2-Higgs Doublet Model Type-I

We show how the 2-Higgs Doublet Model (2HDM) Type-I can explain some excesses recently seen at the Large Hadron Collider (LHC) in $γγ$ and $τ^+τ^-$ final states in turn matching Large Electron Positron (LEP) data in $b\bar b$ signatures, all anomalies residing around 95 GeV. The explanation to such anomalous data is found in the aforementioned scenario when in inverted mass hierarchy, in two configurations: i) when the lightest CP-even Higgs state is alone capable of reproducing the excesses; ii) when a combination of such a state and the CP-odd Higgs boson is able to do so. To test further this scenario, we present some Benchmark Points (BPs) of it amenable to phenomenological investigation.

hep-ph↗

arXiv2025

Constraining the 3HDM Parameter Space using Active Learning

One of the standard ways to study scenarios beyond the Standard Model involves extending the Higgs Sector. This work examines the Three Higgs Doublet Model (3HDM) in a Type-Z or democratic setup, where each Higgs doublet couples exclusively to a specific type of fermion. The particle spectrum of the 3HDM includes four charged Higgs bosons, two CP-odd scalars, and three CP-even scalars. This work investigates the allowed mass and coupling parameter space in the Type-Z 3HDM after imposing all theoretical and experimental constraints. We extract the allowed parameter space under three distinct alignment-limit conditions or mass hierarchies leveraging machine learning techniques. Specifically, we analyze scenarios where the 125 GeV Higgs is the lightest, an intermediary, or the heaviest CP-even Higgs boson. Our findings indicate that while a single lighter CP-even Higgs boson below 125 GeV still remains a possibility, the presence of two lighter Higgses is ruled out.

hep-ph↗

arXiv2024

A Machine Learning-based Anomaly Detection Framework in Life Insurance Contracts

Life insurance, like other forms of insurance, relies heavily on large volumes of data. The business model is based on an exchange where companies receive payments in return for the promise to provide coverage in case of an accident. Thus, trust in the integrity of the data stored in databases is crucial. One method to ensure data reliability is the automatic detection of anomalies. While this approach is highly useful, it is also challenging due to the scarcity of labeled data that distinguish between normal and anomalous contracts or inter\-actions. This manuscript discusses several classical and modern unsupervised anomaly detection methods and compares their performance across two different datasets. In order to facilitate the adoption of these methods by companies, this work also explores ways to automate the process, making it accessible even to non-data scientists.

stat.AP↗