The Indian Scintillator Matrix for Reactor Anti-Neutrino detection—ISMRAN experiment aims to detect electron anti-neutrinos ( _e) emitted from a reactor via inverse beta decay reaction (IBD). The setup, consisting of 1 ton segmented Gadolinium foil wrapped plastic scintillator array, is planned for remote reactor monitoring and sterile neutrino search. The detection of prompt positron and delayed neutron from IBD will provide the signature of _e event in ISMRAN. The number of segments with energy deposit (N_bars) and sum total of these deposited energies are used as discriminants for identifying prompt positron event and delayed neutron capture event. However, a simple cut based selection of above variables leads to a low _e signal detection efficiency due to overlapping region of N_bars and sum energy for the prompt and delayed events. Multivariate analysis (MVA) tools, employing variables suitably tuned for discrimination, can be useful in such scenarios. In this work we report the results from an application of artificial neural network—the multilayer perceptron (MLP), particularly the Bayesian extension—MLPBNN, to the simulated signal and background events in ISMRAN. The results from application of MLP to classify prompt positron events from delayed neutron capture events on Hydrogen, Gadolinium nuclei and also from the typical reactor γ-ray and fast neutron backgrounds is reported. An enhanced efficiency of ~ 91% with a background rejection of ~ 73% for prompt selection and an efficiency of ~ 89% with a background rejection of ~ 71% for the delayed capture event, is achieved using the MLPBNN classifier for the ISMRAN experiment.

Searching for very-high-energy photons arising from dark matter interactions in selected astrophysical environments is a promising strategy to probe the existence and particle nature of dark matter. Among the many particle candidates, motivated by the extensions of the Standard Model, Weakly Interacting Massive Particles (WIMPs) are considered the most compelling candidate for the elusive dark matter in the universe. In this contribution, we report an overview of the important developments in the field of indirect searching for dark matter through cosmic gamma-ray observations. We mainly focus on the role of atmospheric Cherenkov telescopes in probing the dark matter. Finally, we emphasize the opportunities for the Major Atmospheric Cherenkov Experiment (MACE) situated in Hanle, India, to explore WIMPs in the mass range of 200 GeV to 10 TeV for Segue1 and Draco dwarf–spheroidal galaxies.

Understanding the nature of dark matter (DM) and its detection remains one of the most significant unsolved problems in astroparticle physics and cosmology. Considerable efforts have been devoted to the detection of DM through both direct and indirect approaches. Gamma-ray observations offer a powerful probe for the indirect detection of DM. In particular, the spectral features of gamma rays produced through DM interactions are strongly dependent on the underlying annihilation channels into the Standard Model (SM) particles. In this work, we investigate the role of annihilation branching fractions in determining the $\gamma$-ray emission from dark matter within the framework of the Inert Doublet Model (IDM). The lightest neutral inert scalar, which serves as a viable DM candidate, can annihilate into various SM particles, including fermions, gauge bosons, and Higgs bosons, depending on DM mass and the model parameters. We analyze how the branching fractions into these final states influence the resulting $\gamma$-ray spectra and fluxes. Our study demonstrates that different dominant annihilation channels produce distinct spectral features, significantly affecting the predicted high-energy $\gamma$-ray signals. By examining the dependence of $\gamma$-ray emission on the branching behavior of DM within IDM, we identify regions of parameter space that can provide better experimental constraints while remaining consistent with the relic density requirements. The results highlight the importance of annihilation branching fractions in interpreting indirect detection signals and provide insights into distinguishing DM within IDM from other weakly interacting massive particles (WIMPs) scenarios. This work underscores the potential of $\gamma$-ray observations as a sensitive probe of the IDM parameter space and its underlying annihilation dynamics. Variations in the branching ratios directly influence the resulting $\gamma$-ray spectra, thereby affecting the prospects for indirect search of DM with the ground-based $\gamma$-ray telescopes such as the Major Atmospheric Cherenkov Experiment (MACE).

We report measurement of reactor based electron anti-neutrinos from a prototype array of plastic scintillator bars ( mini-ISMRAN ) located inside Dhruva research reactor hall, BARC. The detector setup took data for 128 days for reactor on (RON) and 51 days for reactor off (ROFF) condition. A detailed analysis procedure is developed to select the anti-neutrino candidate events based on the energy deposition, number of bars hit as well as topological event selection criteria in position and time. Each of these selection criteria are compared with Monte Carlo based simulations and further an embedding technique is used to estimate the efficiencies from a data driven background study. The obtained anti-neutrino like events in RON condition are 218 $\pm$ 50 (stat) $\pm$ 37 (sys) after background subtraction. The obtained results are compared with theoretical estimation which yields 214 $\pm$ 32 (sys) anti-neutrino events for the RON condition.

Indian Scintillator Matrix for Reactor Anti-Neutrino (ISMRAN) experiment is the first indigenous effort in the country to measure the reactor based antineutrinos at very close distances ($\sim$13 m) from the reactor core. The experiment is setup in DHRUVA research reactor and has been in the data taking mode since January 2022. The main goal of ISMRAN is to understand the Reactor Anti-neutrino Anamoly from a reactor core, which utilizes natural uranium as fuel. All previous measurements are performed using highly enriched ${}^{235}U$ fuel and observed a deficit of 4-6$\%$ in the antineutrino yield when compared with theory predictions. In this proceedings, we present first results from the complete ISMRAN setup at DHRUVA reactor hall. We will summarize the foreground activities that were carried out for the understanding of the ISMRAN detector response. A new generation of experiments for future, involving the measurement of reactor antineutrinos using coherent elastic scattering will also be discussed.