Fermionic dark matter in leptoquark portal

We investigate a beyond standard model (SM) portal scenario for dark matter (DM) particle with leptoquark being the mediator field. Leptoquark, a colored particle having both baryon and lepton number, allows the DM to interact with the SM fields via renormalizable interaction. By focusing on a vector leptoquark portal with Majorana fermion DM candidate, we find the only unknown coupling in the model is sensitive to all three main features of a DM model namely, relic density, direct detection as well as indirect detection, while being consistent with collider data. We explore the parameter space of the portal with minimum of its field content and find that AMS-02 data for antiproton flux imposes stringent bound till date and excludes the DM mass up to 400GeV. The LUX 2016 data for DM-neutron scattering cross section allows the region compatible with relic density, however the future sensitivity of LUX-ZEPLIN experiment can probe the model up to its perturbative limit.Comment: Matches with the published versio

Implications of right-handed neutrinos in B−LB-L extended standard model with scalar dark matter

We investigate the Standard Model (SM) with a $U(1)_{B-L}$ gauge extension where a $B-L$ charged scalar is a viable dark matter (DM) candidate. The dominant annihilation process, for the DM particle is through the $B-L$ symmetry breaking scalar to right-handed neutrino pair. We exploit the effect of decay and inverse decay of the right-handed neutrino in thermal relic abundance of the DM. Depending on the values of the decay rate, the DM relic density can be significantly different from what is obtained in the standard calculation assuming the right-handed neutrino is in thermal equilibrium and there appear different regions of the parameter space satisfying the observed DM relic density. For a DM mass less than $\mathcal{O}$(TeV), the direct detection experiments impose a competitive bound on the mass of the $U(1)_{B-L}$ gauge boson $Z^\prime$ with the collider experiments. Utilizing the non-observation of the displaced vertices arising from the right-handed neutrino decays, bound on the mass of $Z^\prime$ has been obtained at present and higher luminosities at the LHC with 14 TeV centre of mass energy where an integrated luminosity of 100fb$^{-1}$ is sufficient to probe $m_{Z'} \sim 5.5$ TeV.Comment: Matches with published versio

Phenomenology of Higgs bosons in inverse seesaw model with Type-X two Higgs doublet at the LHC

Type-X two Higgs doublet model is known to explain the muon $g-2$ anomaly with a relatively light charged Higgs boson at large $\tan\beta$. The light charged Higgs boson has been searched in the main $\tau \nu$ mode at the colliders. Invoking a scenario of inverse seesaw as the origin of neutrino masses and mixing, the charged Higgs boson can decay additionally to right-handed neutrinos which leads to interesting phenomenology. Considering generic lepton flavour violating signatures at the final states, a $5\sigma$ discovery can be achieved with the early data of LHC, at 14 TeV, for relatively large inverse seesaw Yukawa coupling $Y_N$. The very light pseudoscalar and charged Higgs boson mass reconstruction are performed using the new modes and the results look promising. The inverse seesaw Yukawa coupling is shown to be probed down to $Y_N \sim 0.2$ at HL LHC with 3000 fb$^{-1}$.Comment: 20 pages, 8 figures and 9 tables, reference adde

Testing WWγWW\gamma vertex in radiative muon decay

Large numbers of muons will be produced at facilities developed to probe lepton flavor violating process $\mu\to e\gamma$. We show that by constructing a suitable asymmetry, radiative muon decay $\mu\to e \gamma\nu_\mu\bar{\nu}_e$ can also be used to test the $WW\gamma$ vertex at such facilities. The process has two missing neutrinos in the final state and on integrating their momenta, the partial differential decay rate shows no radiation-amplitude-zero. We establish, however, that an easily separable part of the normalized differential decay rate, odd under the exchange of photon and electron energies, does have a zero in the case of standard model (SM). This "new type of zero" has hitherto not been studied in literature. A suitably constructed asymmetry using this fact, enables a sensitive probe for the $WW\gamma$ vertex beyond the SM. With a simplistic analysis, we find that the $C$ and $P$ conserving dimension four $WW\gamma$ vertex can be probed at ${\cal O}(10^{-2})$ with satisfactory significance level.Comment: 9 pages, 4 figure

BOREAL QUEST

Honorable Mention, Writing Contes