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Maimoona Razzaq

Publications and source records attributed to Maimoona Razzaq.

5 recordsLinked to original sources

Electro-Weak Phase Transitions and Collider Signals in the Aligned 2-Higgs Doublet Model

We show that the Aligned 2-Higgs Doublet Model (A2HDM) is a framework able to simultaneously accommodate strong first order electro-weak phase transitions, in turn generating detectable gravitational waves as well as a variety of Higgs boson signals (involving both the Standard Model state and its companions, both neutral and charged) accessible at the Large Hadron Collider (LHC). We map the corresponding expanse of parameter space where such a phenomenology is realised in terms of the relative values of the masses of the discovered Higgs boson and the extended Higgs sector states of this model: two neutral ones (a CP-even and a CP-odd) plus a pair of charged ones. We find that both the Laser Interferometer Space Antenna experiment and High-Luminosity LHC can test such a scenario within their lifetime. This study thus sets the stage for a two-prong complementary approach able to scrutinise the extended Higgs sector of the A2HDM in both its high and low temperature manifestations.

hep-ph

Probing the Electroweak Phase Transition in the Dark Sector

We study an extension of the Standard Model with a dark SU(2) gauge group, where a dark scalar doublet interacts with the Standard Model Higgs through a portal coupling, inducing mixing after symmetry breaking. A custodial symmetry ensures the stability of the dark gauge bosons, making them viable dark matter candidates. Scanning the parameter space of the model under collider and astrophysical constraints, we find regions that yield the observed relic density and strong first-order phase transitions. The resulting gravitational-wave signals fall within the reach of upcoming space-based detectors.

hep-ph

Phase transitions and gravitational waves in a non-abelian vector dark matter scenario

We study a scenario where the Standard Model is extended by a SU(2) gauge group in the dark sector. The three associated dark gauge bosons are stabilised via a custodial symmetry triggered by an additional dark SU(2) scalar doublet, thus making them viable dark-matter candidates. After considering the most recent constraints for this model, we analyse the phase transition dynamics and compute the power spectrum of resulting stochastic gravitational-wave background. Finally, we find regions of the parameter space yielding the observed dark-matter relic density while also leading to strong enough phase transition with an associated gravitational-wave signal reaching the sensitivity of future space-based gravitational-wave detector, such as LISA, DECIGO, BBO, TianQin or Taiji.

hep-ph

Electroweak phase transition in a vector dark matter scenario

This study explores the parameter space of a minimal extension of the Standard Model with a non-abelian $SU(2)$ group, in which the gauge bosons are stable and acquire mass through a mechanism of spontaneous symmetry breaking involving a new scalar doublet which interacts with the Higgs boson through a quartic coupling. The exploration aims to assess whether it is possible to obtain a first-order phase transition while ensuring that the gauge bosons are viable dark matter candidates. Theoretical, astrophysical and collider bounds are considered. The results are then tested against the sensitivity of future experiments for the detection of gravitational wave signals.

hep-ph

Study of Nonstandard Interactions in Rare Decays of Hyprons with Missing Energy

We study rare decays of hyperons involving di-neutrinos in the final state in the standard model and compare them with other models. It is claimed that the branching ratio calculated in this article are 2 times the values of 331 model and exceptionally large than the previously calculated values. We explore the nonstandard neutrino interactions (NSI) and constrain NSIs free parameter with these decays. We obtain stringent bounds on of O(0.01). We show that branching ratios (Br) could be in the range of BES III if constraints are O(0.3).

hep-ph