Research Projects

We summarize 4 different research ideas that I want to pursue during next the 3 years. (A) The discovery of Galactic diffuse sub-PeV gamma-rays by the LHAASO and Tibet AS_\gamma collaboration has revolutionized the Milky Way high-energy astrophysics. We want to utilize these discoveries to test beyond the Standard Model (BSM) physics. I propose to utilize these observations, along with an understanding of how these gamma-rays are produced from cosmic-ray interactions with the Galactic gas to probe the annihilation and decay signatures of heavy dark matter (with masses above 1 TeV). The specific hypothesis that I want to test is dark matter (DM) annihilation or decay into pairs of Standard Model (SM) particles. Due to the large mass of the DM particle, a large flux of gamma-rays will be produced from every SM final state, and we aim to test whether the LHAASO observations contain hints of these photons. Due to the new energy range being probed by the LHAASO observations, it is inevitable that we will be probing new parts of parameter space for DM mass and annihilation cross-section or decay lifetimes, leading to a deeper understanding of the dark sector of the Universe. (B) I also propose to conduct a sensitivity study for axion-like particles (ALPs) and their mixing with photons using the ultra-high energy (UHE) gamma-rays (energies greater than 10^19 eV) that are inevitably produced as a result of the GZK process: UHE cosmic-rays interact with the cosmic microwave background photons and get attenuated. UHE neutrinos and gamma-rays are produced inevitably in this process. Although these have not yet been detected, a near future detection is expected. Our objective is to conduct a BSM physics search with the upcoming discovery of these UHE gamma-rays. ALPs mix with photons, and this results in a change in the propagation of gamma-rays. Most notably, gamma-rays can get converted to ALPs and evade attenuation. This process can result in an increased gamma-ray flux (i.e., less attenuation) compared to the standard astrophysical scenario. We will conduct the first sensitivity study in the plane of ALP mass and its couplings to photons using upcoming observations of UHE gamma-rays. Due to the extremely high energy of the gamma-rays, I am expecting to probe new parts in the parameter space. ALPs are predicted in various UV-complete models like string theory and grand unified theories, thus, our proposal to explore for new regions of parameter space would be an extremely significant step towards discovering the contents of the dark sector. (C) Another area in which I would like to contribute via this project is gamma-ray astroparticle physics. My aim is to test whether galaxy mergers emit high-energy (energies greater than 1 GeV) gamma-rays. We did not find significant neutrino emission from galaxy mergers: a search for gamma-rays will help us to understand whether leptonic processes are active in these astrophysical sources. (D) Another major area that I propose to concentrate on for this project is to identify astrophysical sites that are the sources of high-energy neutrinos. Although, the IceCube collaboration has discovered a diffuse flux of high-energy (energies greater than about 10 TeV) neutrinos, and two point sources (TXS 0506+056 and NGC 1068), these source classes are unable to explain the entire diffuse astrophysical flux. I will test whether supermassive black hole binaries (SMBBHs) give rise to these high-energy neutrinos. Theoretically, it has been proposed that SMBBHs can accelerate cosmic-rays, and give rise to high-energy neutrinos via cosmic-ray interactions with surrounding gas and low-energy photons. We will use the public 10-year muon neutrino data-set for this search. Using catalogs of SMBBHs, I aim to test this hypothesis: a positive result will improve our understanding of the high-energy Universe, and a lack of neutrinos will further our understanding of cosmic-ray acceleration and its interactions.