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P. Agarwal

Publications and source records attributed to P. Agarwal.

12 recordsLinked to original sources
arXiv2026

Robust watt-level continuous-wave deep-ultraviolet lasers near 230 nm

Continuous-wave (CW) deep-ultraviolet (DUV) lasers near 230~nm enable laser cooling of AlF, Cd, and Zn, but second-harmonic generation below 237~nm relies in practice on beta-barium borate (BBO), whose walk-off and UV-induced degradation hinder sustained operation. We demonstrate compact, affordable VECSEL-based systems informed by four years of operating 14 DUV cavities in 12 laser systems across six European laboratories. External LBO cavities produce nearly 4~W at 463~nm with 94% cavity efficiency. We compare spherically and elliptically focused Brewster-cut BBO cavities with a normal-incidence AR-coated design. The AR-coated cavity delivers the highest power and efficiency, reaching 1.0~W at 51% cavity and 44% external efficiency; the spherical Brewster cavity reaches 700~mW and maintains constant circulating power over 70~h, while elliptical focusing reduces peak intensity sixfold and improves beam quality, albeit with greater alignment sensitivity. Collaboration-designed DUV optics, AlF spectroscopy, and Cd trapping validate the system.

physics.atom-ph↗
arXiv2025

Magneto-optical trapping of aluminum monofluoride

Magneto-optical trapping of molecules has thus far been restricted to molecules with $^2\Sigma$ electronic ground states. These species are chemically reactive and only support a simple laser cooling scheme from their first excited rotational level. Here, we demonstrate a magneto-optical trap (MOT) of aluminum monofluoride (AlF), a deeply bound and intrinsically stable diatomic molecule with a $^1\Sigma^+$ electronic ground state. The MOT operates on the strong A$^1\Pi\leftarrow{}$X$^1\Sigma^+$ transition near 227.5~nm, whose Q$(J)$ lines are all rotationally closed. We demonstrate a MOT of about $6\times 10^4$ molecules for the $J=1$ level of AlF, more than $10^4$ molecules for $J=2$ and $3$, and with no fundamental limit in going to higher rotational levels. Laser cooling and trapping of AlF is conceptually similar to the introduction of alkaline-earth atoms into cold atom physics, and is key to leveraging its spin-forbidden a$^3\Pi \leftarrow{}$X$^1\Sigma^+$ transition for precision spectroscopy and narrow-line cooling.

physics.atom-ph↗
arXiv2022

Forward-backward multiplicity distribution with the Chou-Yang model for $pp$ collisions at $\sqrt{s}=$ 0.9, 7 and 8 TeV from the CMS experiment

A Chou-Yang type multiplicity distribution comprising a total multiplicity component and a binomial asymmetry component is used to describe charged hadron multiplicity data at $\sqrt{s}=$ 0.9, 7 and 8 TeV from the CMS experiment at CERN. The data was obtained and processed from the CERN Open Data Portal. For the total multiplicity component, it was found that a convex sum of a Negative Binomial Distribution and a Furry-Yule Distribution is able to describe the shoulder-like structure characteristic of KNO scaling violation well. The mean cluster size produced from collisions was also found to increase with collision energy. A prediction is given for $pp$ collisions at $\sqrt{s}=$ 14 TeV.

hep-ph↗
arXiv2022

Intermittency in pp collisions at $\sqrt{s}=$ 0.9, 7 and 8 TeV from the CMS collaboration

The intermittency-type fluctuations as outlined by Bialas and Peschanski in the 1980s is analysed in $pp$ collisions at $\sqrt{s}=$ 0.9, 7 and 8 TeV from the CMS collaboration at CERN. Our preliminary analysis shows that the intermittency exponents in the bin-averaged scaled factorial moments decrease in magnitude with increasing collision energy at the TeV scale, which suggests that the cascading nature of multiparticle production described by the $α$-model is weakening. We outline possible areas planned for future studies.

hep-ph↗
arXiv2022

Multifractal behaviour in multiparticle production in $pp$ collisions at $\sqrt{s}=$ 0.9, 7 and 8 TeV from the CMS experiment

Multifractal analysis was performed on $pp$ collision data at $\sqrt{s}=$ 0.9, 7 and 8 TeV from the CMS experiment at CERN. The data was obtained and processed from the CERN Open Data Portal. Vertical analysis was used to compute the generalised dimensions $D_q$ and the multifractal spectra $f(α)$ of the data, which reveals the level of complexity of its pseudorapidity distribution. It was found that the $f(α)$ curves widen with increasing collision energy, signalling an increase in branching complexity.

hep-ph↗
arXiv2022

Intermittency analysis of $pp$ collisions at $\sqrt{s}=$ 0.9, 7 and 8 TeV from the CMS experiment

The method of horizontal scaled factorial moments as outlined by Bialas and Peschanski was used to conduct intermittency analysis for $pp$ collisions at $\sqrt{s}=$ 0.9, 7 and 8 TeV from the CMS experiment. The data was obtained and processed from the CERN Open Data Portal. It was found from 1D analysis that the intermittency strength decreases with increasing energy, indicating that the signature of the $α$-model of random cascading that the former is based on seems to be weakening. Intermittency was stronger in 2D, but did not reveal any clear trend with increasing collision energy.

hep-ex↗
arXiv2021

Oscillations in Modified Combinants of Hadronic Multiplicity Distributions

Oscillations in modified combinants ($C_j$s) have been of interest to multiparticle production mechanisms since the 1990s. Recently, there has been a discussion on how these oscillations can be reproduced by compounding a binomial distribution with a negative binomial distribution. In this work, we explore a stochastic branching model based on a simple interaction term $λ\overlineψϕψ$ for partons and propose a hadronization scheme to arrive at the final multiplicity distribution. We study the effects that compounding our model with a binomial distribution has on $C_j$s and explore its physical implications. We find that there is a significant difference in the oscillations in $C_j$s between high energy $pp$ and $p\bar{p}$ scattering that our model can reproduce.

hep-ph↗
arXiv2020

Numerical solutions to Giovannini's parton branching equation up to TeV energies at the LHC

Giovannini's parton branching equation is integrated numerically using the 4th-order Runge-Kutta method. Using a simple hadronisation model, a charged-hadron multiplicity distribution is obtained. This model is then fitted to various experimental data up to the TeV scale to study how the Giovannini parameters vary with collision energy and type. The model is able to describe hadronic collisions up to the TeV scale and reveals the emergence of gluonic activity as the centre-of-mass energy increases. A prediction is made for $\sqrt{s}$ = 14 TeV.

hep-ph↗
arXiv2020

Effects of phase space variables on oscillations of modified combinants

It has been shown recently that additional information can be obtained from charged particle multiplicity distribution by investigating their modified combinants $C_j$, which exhibit periodic oscillatory behaviour. The modified combinants obtained from experimental data can be expressed in a recurrent form involving the probability of obtaining $N$ charged particles $P(N)$, scaled by the void probability $P(0)$. The effects of various experimental observables such as $|η|$, $p_T$ and centre-of-mass collision energy $\sqrt{s}$ on the oscillatory behaviour of $C_j$ will be discussed.

hep-ph↗
arXiv2015

Solvability of a non-local problem with integral transmitting condition for mixed type equation with Caputo fractional derivative

In the present paper, we discuss solvability questions of a non-local problem with integral form transmitting conditions for diffusion-wave equation with the Caputo fractional derivative in a domain bounded by smooth curves. The uniqueness of the solution of the formulated problem we prove using energy integral method with some modifications. The existence of solution will be proved by equivalent reduction of the studied problem into a system of second kind Fredholm integral equations.

math.AP↗
arXiv1998

Anomalous Low Temperature States in CeNi2Ge2

Ambient pressure studies on high purity single crystals of the stoichiometric 4f-electron metal CeNi2Ge2 reveal anomalous low temperature forms of the resistivity which challenge our understanding of the metallic state. Comparisons are made with the isostructural and isoelectronic compound CePd2Si2 near the border of magnetism at high pressure, and possible reasons for this novel non-Fermi liquid form of the resistivity are discussed. Phase diagrams of further anomalies are presented, which involve a loss of resistance at low temperature in some samples of CeNi2Ge2 and unexpected high pressure phases.

cond-mat.str-el↗