Models incorporating moderately heavy dark matter (DM) typically need charged (scalar) fields to establish admissible relic densities. Since the DM freezes out at an early epoch, thermal corrections to the cross sections can be important. Here, we study the IR behaviour at finite temperatures, of dark matter annihilation cross sections, which potentially contains both both linear and...
We have explored the parameter space for the phenomenological minimal supersymmetric standard model (PMSSM) with specific focus on the region with a light neutralino dark matter (with mass less than half the mass of the Higgs), which is consistent with current collider and astrophysical constraints. We show that the latest results from the LHC searches for sparticles and direct detection...
We study the phenomenological signatures associated with a light fermiophobic Higgs boson within the type-I two-Higgs-doublet model at the HL-LHC. Our exhaustive parameter scan revealed a captivating mass range between 1 GeV and 10 GeV. This range retains a substantial number of viable parameter points, primarily due to the current experimental difficulties in probing soft decay products of...
The early Universe represents a unique laboratory for frontier physics, providing extreme conditions and amazing chances to test theoretical models. A large class of cosmological phenomena may allow us to probe particle physics at energy scales much beyond the reach of current and future colliders. Within this class, first order phase transitions cover a privileged role since they may leave...
In this talk, I will discuss different searches for neutrino mass models, particularly emphasizing the updates for LHC and prospect for HL-LHC. Special emphasize will be given on heavy neutral lepton candidates. I will also briefly touch upon the cosmological implications of few of the neutrino mass models.
We analyse the cross-sections for each of the 2 $\to$ 2 scattering processes with the modified propagator(s) at the finite temperature in the dense fluid of a strongly interacting pion nucleon system ($\pi N$) that are observed in relativistic heavy ion collisions and neutron star mergers. We examine the shape profile of the resulting transport coefficients like shear viscosity, bulk...
Light dark matter (DM) is getting increasingly more important in our quest to probe the dark sector physics. Direct detection of a sub-GeV scale dark matter is difficult as it lacks sufficient kinematic heft to have significant nuclear or electron recoil. In this regard, a boosted dark matter plays an interesting role. Before attempting to detect a boosted dark matter, we explore a possible...
I will talk about some extremely interesting results from CMS and ATLAS on the search of new resonances, and show their theoretical implication.
We discuss the possibility of generating the observed baryon asymmetry of the Universe by introducing a Majorana fermion coupled to quarks. We discuss decay and scattering processes. We explore the possibility of probing such a scenario using neutron-antineutron oscillation.
There is a long-standing anomaly in the ratio of the decay width for $\psi(3770)\to D^0\overline{D^0}$ to that for $\psi(3770)\to D^+D^-$ at the level of $9.5\,\sigma$. A similar anomaly exists for the ratio of $\phi(1020)\to K_\text{L}^0K_\text{S}^0$ to $\phi(1020)\to K^+K^-$ at $2.1\,\sigma$. In this study, we reassess the anomaly through the lens of Gaussian wave-packet formalism. Our...
The application of deep learning techniques to theoretical particle physics has recently witnessed explosive growth, opening up exciting new avenues for exploration. The integration of deep learning into theoretical particle physics is still in its early stages, but it holds immense potential for future breakthroughs. As these techniques continue to evolve and become more sophisticated, we can...
Our search for new physics scenarios beyond the standard model requires special attention to the light particles, as they could have escaped our conventional searches. We focus on the prospect of detecting light long-lived particles (LLP) coming from the decays of SM Higgs boson and B-mesons at future colliders. Dedicated LLP detectors can play a crucial role in probing highly displaced light...
Neutrino flavor oscillation is a widely studied physical phenomenon with significant implications for our understanding of particle physics and the search for physics beyond the standard model. Oscillation arises due to the mixing between flavor and mass eigenstates, and their evolution over time. It is a quantum system where flavor transitions are typically studied using probabilistic...
Charged lepton flavor violation (cLFV) processes, potentially important for
various Beyond the Standard Model Physics scenarios, are analyzed in the
Standard Model Effective Field Theory (SMEFT) framework. We consider the most
relevant 2 quark-2 lepton $(2q2\ell)$ operators for the leptonic and
semi-leptonic LFV B-decay (LFVBD) processes $B_s\to \mu^+e^- , B^+\to
K^+\mu^+e^-, B^0\to...
The emergence of jets, bunches of collimated hadrons, in high-energy colliders is a prevalent phenomenon. In the current LHC context, along with traditional narrow QCD jets, the study of fat jets, which may appear as a result of the decay of a heavy particle, has become an essential part of collider studies. Current jet clustering algorithms, namely $k_t$-type sequential recombination...
In this talk, I will demonstrate how having two WIMPs, each with different masses, and mass splitting with the NLSP, generated at a collider through a decay chain, can result in double peaks in the missing energy or missing transverse momentum distribution of the multilepton signal. I will also outline a set of criteria to identify and segregate the second peak in the missing energy spectrum,...
We constrain the parameter space of a simplified fermionic dark matter model with a spin-0 mediator from low energy processes. FCNC observables like neutral pseudoscalar meson mixing, rare decays of $ B_0, B_s^0, K $ meson, global fit of all the $ b \to s \ell \ell $ observables, invisible decays of B and K meson are considered along with FCCC observables like $ t \to b W_{\mu} $ anomalous...
We will discuss an Effective Field Theory which extends the SM by an Axion-Like Particle (ALP) and mainly focus on the interactions of a light ALP to heavy SM particles. The talk is dedicated to the role of the LHC in probing ALP couplings particularly with the Higgs boson and the gauge bosons. We discuss a recent proposal to hunt for ALP signals in the non-resonant regime, i.e. when the ALP...
We study a scenario where origin of dark matter is related to the Dirac nature of neutrino, known as the light Dirac neutrino portal dark matter (DNPDM). In such DNPDM set up, light dirac neutrinos take the role of mediating the interactions between dark matter (DM) and standard model (SM) bath. Here, we consider a UV complete model in gauged B-L framework extended by three species of right...
In this study, we propose a new version of the Scotogenic model, it is an economically appealing theoretical framework which addresses two problems of particle physics, neutrino mass generation and dark matter. The Scotogenic model generates neutrino mass via a $1$-loop Feynman diagram by extending the standard model by the $Z_2$ discrete symmetry.
In our model, we extend the standard model...
The Inert Triplet Model (ITM) is a much-studied Dark Matter model that extends the Standard Model (SM) of particle physics with a scalar $SU(2)$ triplet having hypercharge $Y=0$. The various DM experiments rule out a significant portion of the parameter space, cornering the model to an allowed region of TeV scale masses. The compressed mass spectrum of the scalars lead to displaced decays,...
In recent years, there has been a growing interest in the direct detection of sub-GeV dark matter, which is theoretically well-motivated. However, probing sub-GeV cold dark matter particles has posed a persistent challenge, as their typical momenta are insufficient to induce recoils above the thresholds of conventional direct detection experiments. Notably, even very strongly interacting dark...
Effective field theory (EFT) offers a powerful framework for indirect searches of physics beyond the Standard Model (BSM). Standard Model Effective Field Theory (SMEFT) is one of the most common EFT approaches for such searches. In SMEFT, the $SU(2)_L\times U(1)_Y$ electroweak (EW) symmetry of the Standard Model is linearly realized. However, it is possible that more general EFTs, such as the...
Small neutrino masses can be sourced by a tiny vacuum expectation value of a leptophilic Higgs doublet, and mediated by Quasi-Dirac heavy neutrinos. In such simplest linear seesaw picture the neutrino mass mediators can be accessible to colliders. We describe novel charged Higgs and heavy neutrino production mechanisms that can be sizeable at $e^-e^+$, $e^-\gamma$ and $\mu^-\mu^+$ colliders....
The Dirac scotogenic model provides an elegant mechanism which explains small Dirac neutrino masses and neutrino mixing with a single symmetry simultaneously protecting the ''Diracness'' of the neutrinos and the stability of the dark matter candidate. In addition to exploring the phenomenology of dark matter, we will also investigate the implications for lepton flavor violation, the muon...
We focus on a rare, exotic decay channel of the top quark, t → cH, with H decaying to a pair of b-quarks produced at the High Luminosity runs of the Large Hadron Collider. For our study, we propose and implement a new jet tagging algorithm, which is efficient in identifying the said decay mode of the boosted top using a large-R jet with b- and c-tagged jets inside it. Identifying observables...
In a two-component dark matter (DM) set-up, when DM$_1$ is in equilibrium with the thermal bath, the other one, DM$_2$, can be equilibrated only by the sizeable interaction with the DM$_1$, even without any connection with the visible-sector particles. We affirm that such DM candidates (DM$_2$) have unique `freeze-out' characteristics impacting the relic density, direct, indirect and collider...
Left-right symmetric models fill in some of the lacunae in the Standard Model, such as providing an explanation for parity and neutrino masses. But the additional bosons in the theory must be heavy to avoid flavor-changing neutral currents, and the models lack a natural dark matter candidate. The Alternative Left-Right Model, emerging from E6 grand unification, is an attractive variation of...
After briefly presenting the status of the LHC project, the talk will cover some of the recent and the most interesting experimental results of standard model physics.
We study the constraints on the doublet left-right symmetric model coming from the Higgs data. The SU(2)L symmetry of this model is broken by three vacuum expectation values,
k1, k2 and vL. Most model builders assume that vL and k2 are negligibly small compared to k1. We test whether this assumption is valid in light of the measurement of Higgs boson coupling to gauge bosons and third...
In this talk, I will discuss an extension of the Standard Model (SM) with a complex scalar field, known as`flavon', based on the Froggatt-Nielsen mechanism. In an effective theory approach, the SM fermion masses and mixing patterns are generated in orders of the parameter related to the vacuum expectation value of the flavon field and the cut-off of the effective theory. By introducing...
Assuming a conformal phase of the early universe, we discuss the conformal backreaction, by studying the anomaly effective action around flat space and, in parallel, the anomaly induced actions (Fradkin Vilkovisly and Riegert's actions ) in curved space. Gravity is treated classically. Anomalies included take the form both of conformal (parity-even) and of chiral (parity odd)...
We study a scenario where both dark matter (DM) and heavy right-handed neutrino (RHN) responsible for leptogenesis acquire masses by crossing the relativistic bubble walls formed as a result of a supercooled first order phase transition (FOPT) above electroweak scale. This leads to a large out-of-equilibrium abundance of RHN inside the bubble sufficient to produce the required lepton...
In this work, we explore the intriguing possibility of connecting self-interacting dark matter (SIDM) with the recently observed exceptionally bright and long-duration gamma-ray burst (GRB221009A). The proposed minimal scenario involves a light scalar mediator, simultaneously enabling dark matter (DM) self-interaction and explaining the observed very high energy photons from GRB221009A...
Studying cosmic phase transitions is a key focus in modern cosmology and particle physics. Both new and existing physics at any scale can be responsible for catalyzing either a first, second, or cross-over phase transition, which could be thermal or non-thermal with an observable imprint, such as stochastic gravitational waves (GW). Understanding the sources of such primordial waves can serve...
We study the possibility of generating light Dirac neutrino mass via scotogenic mechanism where singlet-doublet fermion dark matter (DM) plays non-trivial role in generating one-loop neutrino mass, anomalous magnetic moment of muon $(g-2)_\mu$ as well as additional relativistic degrees of freedom $\Delta{N_{\rm eff}}$ within reach of cosmic microwave background (CMB) experiments. We show that...
Recent developments in dark matter research have spiked investigations into extended configurations within this mysterious sector. Depending on various parameters within the underlying dark matter model, these extended structures may exhibit distinct properties. Furthermore, investigating their gravitational microlensing signature will be instrumental for observational purposes. In my talk, I...
Extra dimensional models are very popular and useful framework to address
many important problems in particle physics. On the other hand extension of the Standard Model (SM) with an extra U(1)Lmu−Ltau gauge group is a great motivation to solve muon (g-2) anomaly (recently 5.1 sigma deviation). Here we considered an extra dimensional U(1)Lmu − Ltau model where only the Kaluza-Klein (KK) modes...
We study the strong first-order phase transition (SFOPT) associated with $SU(2)_R\times U(1)_{B-L}$-breaking in the doublet left-right symmetric model (DLRSM), and the resulting stochastic gravitational wave (GW) background. For different values of the symmetry-breaking scale $v_R =20,~30$, and $50$ TeV, we construct the one-loop finite temperature effective potential to explore the parameter...
In a scattering process in a thermal plasma, thermal fluctuation alongside with quantum fluctuation affects the annihilation cross section of particles. This is important in the context to dark matter annihilation cross section since the relic densities are now being more precisely measured. We investigate the effect of thermal fluctuation on the annihilation cross section of a $SU(2) \times...
We investigate the effect of photon-axion-like particle (ALP) oscillations in the gamma-ray spectra of FSRQ B1426+326 measured by Fermi-LAT and MAGIC around the flaring activity in January 2020. We set 95% confidence level (C.L.) upper limit on the photon-ALP coupling constant $g_{a\gamma} < 2\times10^{-11}$ GeV$^{-1}$ for ALP masses $m_{a} \sim 10^{-10}-10^{-9}$ eV. Assuming the hadronic...
The lightest Neutralino is a good Dark Matter (DM) candidate
in the R-parity conserving Minimal Supersymmetric Standard Model (MSSM). In this work, we consider light Higgsino-like Neutralino as the Lightest
Stable Particle (LSP), thanks to a relatively small $\mu$ parameter. We then estimate the prominent radiative corrections to the Neutralino-Neutralino-Higgs boson vertices.
We show that...
Modular symmetries offer a dynamic approach to understanding the flavour structure of leptonic mixing. Using the modular $\mathcal{A}_4$ flavour symmetry integrated in a type-II seesaw, we propose a simple and minimalistic model that restricts the neutrino oscillation parameter space and, most importantly, introduces a sum rule in the physical neutrino masses. When combined with the mass...
We study a scotogenic extension of the minimal gauged $L_{\mu}-L_{\tau}$ model, including three right-handed singlet fermions and a scalar doublet all odd under an in-built $Z_2$ symmetry to explain the anomalous magnetic moments of the muon, CDF-II W-mass anomaly, and the 95 GeV excess reported by the CMS collaboration. While the minimal model can successfully explain the muon $(g-2)$ and...
Extra dimensions (ED) offer a valuable tool for constructing intricate mod-
els and exploring potential new physics phenomena. Our focus is to extand
Standard Model (SM) by introducing an U(1) Lmu − Ltau gauge group in the
framework of ED, which serves as a compelling initiative aimed at addressing
the muon (g − 2) anomaly. In this model, only the Kaluza-Klein (KK) modes of
the extra...
We study the two-component boosted dark matter (DM) scenario in a neutrinophilic two-Higgs doublet model (ν2HDM), which comprises one extra Higgs doublet with a MeV scale CP-even scalar H. This model is extended with a light (∼ 10 MeV) singlet scalar DM ϕ3, which is stabilized under the existing Z2 symmetry and can only effectively annihilate through scalar H. As the presence of a light H...
In this work, Left-Right Symmetric (LRSM) has been realized with the modular group of level 3, that is, $\Gamma(3)$ and weight 2, which is isomorphic to non-abelian discrete symmetry group $A_4$. It is a well-known fact that there are physics beyond the Standard Model framework, where several phenomenological studies can be carried out. In our present work, we are concerned about the study of...
Cosmological observations offer valuable methods for probing various characteristics of Dark Matter (DM). We examine the cosmological implications of higher-dimensional Non-Relativistic Effective Field Theory (EFT) operators for Dark Matter(DM) - electron interactions. We focus on velocity-independent operators and simultaneously incorporate DM-electron scattering and DM annihilation into...
We will explore the extensions of the Standard Model (SM) incorporating a new $U(1)$ gauge symmetry. These extensions introduce modifications to the SM's gauge anomaly conditions, which in turn impose restrictions on the charges of fermions. While well-studied solutions, such as $B-L$ and linear combinations of $B-L$ and hypercharge, offer straightforward anomaly cancellations, the exploration...
In this study, we examine the phenomenon of photon axion conversion occurring in the spacetime surrounding a black hole. Observations of the black hole in the center of the M87 galaxy (M87 * ) through the Event Horizon Telescope imaged polarized synchrotron emission at 230 GHz on event horizon scales. Specifically, we focus on the potential existence of a magnetic field around the supermassive...
The $\mathcal{Z}_N \times \mathcal{Z}_M$ symmetry is a novel flavour symmetry, that can provide an explanation to the flavour structure of the Standard Model through the Froggatt-Nielsen mechanism. We have investigated the flavour bounds on the minimal $\mathcal{Z}_2 \times \mathcal{Z}_5$, and a non-minimal $\mathcal{Z}_2 \times \mathcal{Z}_9$ version of this symmetry using the current quark...
We investigate the renormalization group scale and scheme dependence of the $H \rightarrow gg$ decay rate at the order N$^4$LO in renormalization-group summed perturbative theory, which employs the summation of all renormalization-group accessible logarithms including the leading and subsequent four sub-leading logarithmic contributions to the full perturbative series expansion. The...
