Arvind Rajaraman
VerifiedUniversity of California, Irvine · Physics & Astronomy
Active 1996–2026
Research topics
- Physics
- Particle physics
- Theoretical physics
- Mathematical physics
- Nuclear physics
Selected publications
arXiv (Cornell University) · 2026-04-30
articleOpen access1st authorCorrespondingWe present an explicit model of leptogenesis via annihilogenesis in which two right-handed Majorana neutrinos couple to the Standard Model lepton doublets and Higgs, and acquire a large mass shift during a strong first-order phase transition of an additional scalar singlet. As bubbles of true vacuum expand, the $χ_a$ are reflected off the walls and confined to shrinking pockets of false vacuum, where the density grows and the dominant CP-violating process is the $2 \to 4$ annihilation $χ_1 χ_1 \to L_1 L_1 Φ^* Φ^*$. Interference between tree-level $W$ and $B$ exchange and one-loop diagrams containing the heavier $χ_2$ produces a CP asymmetry $ε$, which we evaluate numerically and find to lie in the range $|ε| \sim 10^{-9}$--$10^{-7}$ for $\mathcal{O}(1)$ Yukawa couplings. Electroweak sphalerons convert the resulting lepton asymmetry into a baryon asymmetry $Y_{ΔB}$ that reproduces the observed value across a broad region of parameter space, with little sensitivity to the bubble-wall velocity or initial pocket size. The Majorana mass that controls $ε$ is the residual mass of $χ_1$ inside the collapsing pockets rather than its post-transition value, so the usual relation between the singlet mass and the Standard Model active neutrino masses is relaxed. As a result, the upper bound on $|ε|$ from the largest light-neutrino mass that constrains standard thermal leptogenesis does not apply, and the lower limits on the right-handed-neutrino scale and the reheating temperature are relaxed.
The Hilbert Series and the Flavor Invariants of the 3HDM
ArXiv.org · 2026-04-20
articleOpen accessSenior authorWe perform a systematic study of invariant operators in the three-Higgs-doublet model (3HDM). We compute the Hilbert series associated with the global symmetry group of the theory. In addition, we construct explicit expressions for these invariants up to cubic order in the couplings.
The Hilbert Series and the Flavor Invariants of the 3HDM
arXiv (Cornell University) · 2026-04-20
preprintOpen accessSenior authorWe perform a systematic study of invariant operators in the three-Higgs-doublet model (3HDM). We compute the Hilbert series associated with the global symmetry group of the theory. In addition, we construct explicit expressions for these invariants up to cubic order in the couplings.
arXiv (Cornell University) · 2026-04-30
preprintOpen access1st authorCorrespondingWe present an explicit model of leptogenesis via annihilogenesis in which two right-handed Majorana neutrinos couple to the Standard Model lepton doublets and Higgs, and acquire a large mass shift during a strong first-order phase transition of an additional scalar singlet. As bubbles of true vacuum expand, the $χ_a$ are reflected off the walls and confined to shrinking pockets of false vacuum, where the density grows and the dominant CP-violating process is the $2 \to 4$ annihilation $χ_1 χ_1 \to L_1 L_1 Φ^* Φ^*$. Interference between tree-level $W$ and $B$ exchange and one-loop diagrams containing the heavier $χ_2$ produces a CP asymmetry $ε$, which we evaluate numerically and find to lie in the range $|ε| \sim 10^{-9}$--$10^{-7}$ for $\mathcal{O}(1)$ Yukawa couplings. Electroweak sphalerons convert the resulting lepton asymmetry into a baryon asymmetry $Y_{ΔB}$ that reproduces the observed value across a broad region of parameter space, with little sensitivity to the bubble-wall velocity or initial pocket size. The Majorana mass that controls $ε$ is the residual mass of $χ_1$ inside the collapsing pockets rather than its post-transition value, so the usual relation between the singlet mass and the Standard Model active neutrino masses is relaxed. As a result, the upper bound on $|ε|$ from the largest light-neutrino mass that constrains standard thermal leptogenesis does not apply, and the lower limits on the right-handed-neutrino scale and the reheating temperature are relaxed.
ArXiv.org · 2025-12-03
preprintOpen accessThe dynamics of $\mathcal{N}=1$ SUSY gauge theories with matter in adjoint and fundamental representations and the superpotentials given by Arnold's ADE singularities has been extensively studied in the literature. It was also conjectured that supersymmetric models with $W_{A_k}$, $W_{D_{k+2}}$ and $W_{E_7}$ superpotentials possess a dual description. In this paper we revisit the analysis of the moduli space of $A_k$ and $D_{k+2}$ models by considering the duality along nilpotent directions on the moduli space. While our analysis provides additional evidence for the duality conjecture in $W_{A_k}$ models, we show that the duality conjecture fails for the $W_{D_{k+2}}$ models.
Instabilities of gauged Q-balls
Journal of High Energy Physics · 2025-03-12
articleOpen access1st authorCorrespondingA bstract We present the first analytical calculation that shows that perturbations with angular dependence can lead to an instability in gauged Q-balls. We find an explicit condition on the parameters for the Q-ball to become unstable. We compare our predictions to the numerical calculation in Kinach et al., and show agreement, including a correct prediction of the instability/stability of the two parameter points analyzed in that paper.
AI-Driven Financial Assistant for Intelligent Capital Budgeting
2025-11-20
articleCapital budgeting plays a pivotal role in long-term corporate strategy, yet conventional workflows remain spreadsheet-dependent, error-prone, and inaccessible to non-specialists. This paper presents a dialog-based decision-support assistant that unifies financial computations, inferential machine learning, and live market data into a single, browser-based environment. Built using Python 3.11 with frameworks such as Streamlit, NumPy-Financial, and scikit-learn, the system accepts natural-language prompts-such as “NPV cost 600000 flows 150k, 180k, 200k rate nine percent” or “Show me the best project”-and routes them to deterministic functions, machine-learned estimators, or visual renderers. Tested on a synthetic ledger of 100 green-energy investment projects, the assistant correctly identified the mathematically optimal capital allocation 96% of the time. Risk-adjusted return selection improved by 17% over naive heuristics when using Random Forest ranking. Average response latency was measured at 1.8 seconds for text queries and 3.4 seconds for chart-based outputs. The system demonstrates that a conversational interface, when combined with structured financial logic and real-time analytics, offers a compelling and low-cost solution for intelligent capital budgeting support in modern decision environments.
The European Physical Journal C · 2024-04-07 · 8 citations
articleOpen accessAbstract Q-balls are non-topological solitons arising in scalar field theories. Solutions for rotating Q-balls (and the related boson stars) have been shown to exist when the angular momentum is equal to an integer multiple of the Q-ball charge Q . Here we consider the possibility of classically long-lived metastable rotating Q-balls with small angular momentum, even for large charge, for all scalar theories that support non-rotating Q-balls. This is relevant for rotating extensions of Q-balls and related solitons such as boson stars as it impacts their cosmological phenomenology. arXiv:2302.11589
Physical review. D/Physical review. D. · 2024-04-02 · 2 citations
articleOpen access1st authorCorrespondingWe perform a general analysis of thin-wall $Q$-balls in anti--de Sitter (AdS) space. We provide numeric solutions and highly accurate analytic approximations over much of the parameter space. These analytic solutions show that AdS $Q$-balls exhibit significant differences from the corresponding flat-space solitons. This includes having a maximum radius beyond which the $Q$-balls are unstable to a new type of state where the $Q$-ball coexists with a gas of massive particles. The phase transition to this novel state is found to be a zero-temperature third-order transition. This, through the AdS/CFT correspondence, has implications for a scalar condensate in the boundary theory.
Probing muon g-2 at a future muon collider
SciPost Physics · 2024-03-12 · 4 citations
articleOpen accessThe 4.2\sigma <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mn>4.2</mml:mn> <mml:mi>σ</mml:mi> </mml:mrow> </mml:math> discrepancy in the (g-2) <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mo stretchy="true" form="prefix">(</mml:mo> <mml:mi>g</mml:mi> <mml:mo>−</mml:mo> <mml:mn>2</mml:mn> <mml:mo stretchy="true" form="postfix">)</mml:mo> </mml:mrow> </mml:math> of the muon provides a hint that may indicate that physics beyond the standard model is at play. A multi-TeV scale muon collider provides a natural testing ground for this physics. In this paper, we discuss the potential to probe the BSM parameter space that is consistent with solving the (g-2)_{\mu} <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msub> <mml:mrow> <mml:mo stretchy="true" form="prefix">(</mml:mo> <mml:mi>g</mml:mi> <mml:mo>−</mml:mo> <mml:mn>2</mml:mn> <mml:mo stretchy="true" form="postfix">)</mml:mo> </mml:mrow> <mml:mi>μ</mml:mi> </mml:msub> </mml:math> discrepancy in the language of the SMEFT, utilizing the statistical power provided by fitting event rates collected running at multiple energies. Our results indicate the importance of including interference between the BSM and the SM amplitudes, and illustrates how a muon collider running at a handful of lower energies and with less total collected luminosity can better significantly constrain the space of relevant SMEFT coefficients than would be possible for a single high energy run.
Recent grants
Particle Physics and Cosmology in the LHC Era
NSF · $580k · 2007–2011
NSF · $72k · 2004–2008
Frequent coauthors
- 24 shared
Tim M. P. Tait
University of California, Irvine
- 18 shared
Рената Каллош
- 17 shared
Jonathan L. Feng
University of California, Irvine
- 15 shared
Fumihiro Takayama
Kyoto University
- 13 shared
Edi Halyo
- 12 shared
Christopher B. Verhaaren
Brigham Young University
- 11 shared
Julian Heeck
University of Virginia
- 11 shared
Jason Kumar
University of Hawaii System
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