publications

Journal Articles

1. JHEP

   

   Pseudo-Nambu-Goldstone-boson dark matter from three complex scalars

   Riasat Sheikh, Takashi Toma, and Koji Tsumura

   Journal of High Energy Physics, Apr 2025

   Abs DOI Bib HTML

   

   This study explores a dark matter model in which a pseudo-Nambu-Goldstone boson arises as a viable dark matter candidate from the spontaneous and soft breaking of global \(\mathrmU(1)\)symmetries and stabilized by a residual \(\mathbbZ_3\)discrete symmetry. The model introduces three complex scalar fields, singlets under the Standard Model gauge group, and charged under a dark \(\mathrmU(1)_V\)gauge symmetry together with a permutative exchange symmetry among three scalars. These features naturally suppress the dark matter–nucleon scattering cross section by its Nambu-Goldstone boson nature. In addition to conventional annihilation channels, the \(\mathbbZ_3\)structure allows semi-annihilation processes, playing a crucial role in setting the relic abundance. We analyze theoretical and experimental constraints, including relic abundance, Higgs invisible decays, and perturbative unitarity, and evaluate the elastic scattering cross section for boosted dark matter.

   @article{Sheikh:2025nsx,
     archiveprefix = {arXiv},
     author = {Sheikh, Riasat and Toma, Takashi and Tsumura, Koji},
     doi = {10.1007/JHEP08(2025)018},
     dimensions = {true},
     eprint = {2504.19886},
     month = apr,
     isbn = {1029-8479},
     journal = {Journal of High Energy Physics},
     number = {8},
     pages = {18},
     primaryclass = {hep-ph},
     publisher = {arXiv},
     reportnumber = {KYUSHU-HET-319, KANAZAWA-25-01},
     title = {Pseudo-Nambu-Goldstone-boson dark matter from three complex scalars},
     url = {https://doi.org/10.1007/JHEP08(2025)018},
     urldate = {2025-05-08},
     year = {2025},
   }

2. EPJP

   

   Effect of quantum gravity on specific heat of solid

   Sheikh Riasat and Bhabani Prasad Mandal

   The European Physical Journal Plus, Apr 2023

   Abs DOI Bib HTML

   

   All possible theories of quantum gravity suggest the existence of a minimal length. As a consequence, the usual Heisenberg uncertainty principle (HUP) is replaced by a more general uncertainty principle known as the generalized uncertainty principle (GUP). The dynamics of all quantum mechanical system gets modified due to GUP. In this work, we consider both Einstein’s and Debye’s models to find the quantum gravity effect on the specific heat of solids. GUP modified specific heat in Einstein’s model shows usual exponential dominance at low temperatures. Further, the modification to Debye’s specific heat is calculated by considering the GUP modified dispersion relation, which becomes time dependent for elastic waves.

   @article{Riasat:2023vbo,
     author = {Riasat, Sheikh and Mandal, Bhabani Prasad},
     date = {2023-10-24},
     doi = {10.1140/epjp/s13360-023-04585-y},
     dimensions = {true},
     isbn = {2190-5444},
     journal = {The European Physical Journal Plus},
     number = {10},
     pages = {943},
     title = {Effect of quantum gravity on specific heat of solid},
     url = {https://doi.org/10.1140/epjp/s13360-023-04585-y},
     volume = {138},
     year = {2023},
   }

Theses

1. MSc Thesis

   

   Effect of Gravity in Quantum Mechanics

   Sheikh Riasat

   Banaras Hindu University, May 2022

   Abs Bib

   All possible theories of quantum gravity suggest the existence of a minimal length. Therefore, the usual Heisenberg uncertainty principle (HUP) is replaced by a more general uncertainty principle known as the generalized uncertainty principle (GUP). The dynamics of all quantum mechanical system gets modified due to GUP. In this work, we consider various quantum mechanical phenomena and review the correction to their respective Hamiltonian and energy levels. GUP modified quantization of a particle inside a box potential indicates that the space is quantized in the units of \(\alpha_0 l_p\,\)predicting an upper bound of the GUP parameter \(\alpha_0\). Furthermore, the modified Landau levels, simple harmonic oscillator (SHO) and Lamb shift also results in an upper bound of the GUP parameter. Apart from these, we review a relativistic quantum mechanical phenomenon, Dirac oscillator under the effect of magnetic field which is non-oscillating at a certain value of magnetic field even under the effect of gravity.

   @mastersthesis{riasat-Effect-2022,
     author = {Riasat, Sheikh},
     month = may,
     school = {Banaras Hindu University},
     title = {Effect of Gravity in Quantum Mechanics},
     year = {2022},
   }

Miscellaneous

1. Project

   

   Ecology and Conservation Strategy of Bats in Rural Area

   Sheikh Riasat

   Aug 2007

   Abs Bib

   Study was conducted in between Beki and Manas River covering an area of 1100 square kilometers. It extended the Railway line in North and mighty river Brahmaputra in the South. Three different species of bats were detected. These include Indian Fruit Bat, Leaf Nosed Bat and Chungabaduli. Indian Fruit Bat feed on 23 different plant species. They have 7 colonies on 10 different species of plants. Total population of this bat was 3811 during 29 July to 12 August, 2007. There are 2 colonies of leaf Nosed Bat in Assam Type Tin Houses, which were observed. Total population of this bat were 600. They are insectivorous.Chungabaduli have scanty population and remain scattered in the study area. They reside mainly in holes of bamboo posts and roof supports of thresh huts. The hunters kill the Fruit Bats for food and medicine used against Asthma, Body and joint pain and Night blindness. They use Nowsa and Baduliphand to catch bat. Open electrification also killed many fruit bat. Cutting of bat trees (habitat destruction) and killing of Bats are the major threat for the survival of the bat species in the study area. Age of the colonies range from 10-35 years. Average weight of the adults of Fruit bat, Leaf nosed bat and Chingabaduli are 1250 gm (1.25kg), 45.5 gm (0.0455 kg) and 10 gm (.010 kg) respectively. Respective wing span of these bats are 131 cm, 47 cm and 20 cm. Owners of the lands of the bats colonies have a great for the participation of these precious creature. They generally resist the hunters to kill the bats. Fruit bats are not found in those areas where mass people hunt hem for food e.g.: Roha area. One fruit bat is sold in the market for about INR. 35/-.

   @misc{riasat-Ecology-2007,
     author = {Riasat, Sheikh},
     month = aug,
     school = {National Children’s Science Congress},
     title = {Ecology and Conservation Strategy of Bats in Rural Area},
     year = {2007},
   }