We propose a type II seesaw model for light Dirac neutrinos to provide an explanation the recently reported anomaly in W boson mass by CDF collaboration with 7σ statistical significance. In minimal model, required enhancement is obtained at tree level due vacuum expectation value of real scalar triplet, which also plays role generating neutrino mass. Depending upon couplings and masses newly introduced particles, we can have thermally or non-thermally generated relativistic degrees freedom...

Motivated by the recently reported excess in electron recoil events XENON1T collaboration, we propose an inelastic fermion dark matter (DM) scenario within framework of a gauged $L_{\mu}-L_{\tau}$ extension standard model which can also accommodate tiny neutrino masses as well anomalous muon magnetic moment $(g-2)_{\mu}$. A Dirac DM, naturally stabilised due to its chosen gauge charge, is split into two pseudo-Dirac mass eigenstates Majorana term induced singlet scalar takes part generating...

Abstract We propose a new gauged $$B-L$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>B</mml:mi><mml:mo>-</mml:mo><mml:mi>L</mml:mi></mml:mrow></mml:math> extension of the standard model where light neutrinos are Dirac type, naturally acquiring sub-eV mass after electroweak symmetry breaking, without any additional global symmetries. This is realised by choosing different charge for right handed than usual $$-1$$...

We propose a Dirac neutrino portal dark matter scenario by minimally extending the particle content of Standard Model (SM) with three right handed neutrinos ($\nu_R$), fermion candidate ($\psi$) and complex scalar ($\phi$), all which are singlets under SM gauge group. An additional $\mathbb{Z}_4$ symmetry has been introduced for stability $\psi$ also ensuring nature light at same time. Both thermalise plasma due to new Yukawa interaction involving $\nu_R$, $\phi$ while latter maintains...

We propose a scenario where dark matter (DM) can be generated non-thermally due to the presence of light Dirac neutrino portal between standard model (SM) and sector particles. The SM is minimally extended by three right handed neutrinos ($\nu_R$), fermion DM candidate ($\psi$) complex scalar ($\phi$), transforming non-trivially under an unbroken $\mathbb{Z}_4$ symmetry while being singlets gauge group. While $\nu_R$ couplings are considered tiny in order non-thermal or freeze-in regime,...

We study a gauged $B-L$ extension of the standard model where new fermions with fractional charges that play role keeping anomaly free can also explain origin neutrino mass at one loop level as well dark matter. discuss two different versions to realise fermion and scalar matter, both which guarantee matter stability by remnant discrete symmetry $U(1)_{B-L}$ gauge gets spontaneously broken down to. Apart from giving rise observed abundance, has tantalising signatures variety experiments...

Motivated by the fact that origin of tiny Dirac neutrino masses via standard model Higgs field and non-thermal dark matter populating Universe freeze-in mechanism require dimensionless couplings similar order magnitudes $(\sim 10^{-12})$, we propose a framework can dynamically generate such in unified manner. Adopting flavour symmetric approach based on $A_4$ group, construct where coupling to its mother particle occur at dimension six level involving same flavon fields, thereby generating...

We propose a $B-L$ gauged extension of the Standard Model where light neutrino masses arise from type III seesaw mechanism. Unlike minimal model with three right handed neutrinos having unit lepton number each, fermion triplets is however not anomaly free. show that leftover triangle anomalies can be cancelled by two neutral Dirac fermions fractional charges, both which are naturally stable virtue remnant $\mathbb{Z}_2 \times \mathbb{Z}'_2$ symmetry, leading to component dark matter scenario...

We study the possibility of light Dirac neutrino portal dark matter (DM) in an effective field theory (EFT) setup. nature automatically includes its right chiral part $\nu_R$ which, our setup, also acts like a between DM and standard model (SM) particles. Considering fermion singlet stabilised by unbroken $Z_2$ symmetry, we write down all possible dimension-6 operators involving DM-$\nu_R$ as well $\nu_R$-SM which conserve $Z_2$, global lepton number SM gauge symmetries. thermalisation...

The presence of any extra radiation energy density at the time cosmic microwave background formation can significantly impact measurement effective relativistic neutrino degrees freedom or $\mathrm{\ensuremath{\Delta}}{\mathrm{N}}_{\mathrm{eff}}$, which is very precisely measured by Planck Collaboration. Here, we propose a scenario where long-lived inert scalar, weakly coupled to dark sector, decays fermion matter via ``freeze-in'' mechanism plus standard model neutrinos low temperature...

We study the imprints of high scale non-thermal leptogenesis on cosmic microwave background (CMB) from measurements inflationary spectral index () and tensor-to-scalar ratio (r), which otherwise is inaccessible to conventional laboratory experiments. argue that production baryon (lepton) asymmetry subsequent decays inflaton heavy right-handed neutrinos (RHN) RHN SM leptons sensitive reheating dynamics in early Universe after end inflation. Such dependence provides detectable plane well...

Abstract We study the possibility of probing radiative Dirac seesaw model with dark sector particles going inside loop, popularly referred to as scotogenic via measurements effective relativistic degrees freedom $$\Delta {\textrm{N}}_{\textrm{eff}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>Δ</mml:mi> <mml:msub> <mml:mtext>N</mml:mtext> <mml:mtext>eff</mml:mtext> </mml:msub> </mml:mrow> </mml:math> at cosmic microwave background (CMB) experiments. The loop...

We study the phenomenology of a vector dark matter (VDM) in <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>U</a:mi><a:mo stretchy="false">(</a:mo><a:mn>1</a:mn><a:msub><a:mo stretchy="false">)</a:mo><a:mi>X</a:mi></a:msub></a:math> gauged extension Standard Model (SM), which is set type II seesaw framework. When this <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mi>U</e:mi><e:mo stretchy="false">(</e:mo><e:mn>1</e:mn><e:msub><e:mo...

We study the possibility of right-handed neutrino dark matter (DM) in gauged U(1)B−L×Z2 extension standard model augmented by an additional scalar doublet, being odd under Z2 symmetry, to give rise scotogenic scenario radiative masses. Due lepton portal interactions, DM can have co-annihilation channels apart from usual annihilations through ZB−L which much more allowed mass relic abundance criteria, even away resonance region like MDM≈MZB−L/2. This enlarged parameter space is found be...

We study the possibility of keV neutrino dark matter in minimal $U(1)_{B-L}$ gauge extension standard model where three right handed neutrinos are automatically included due to requirement anomaly cancellations. Without considering extra additional particles or symmetries, we consider lightest be mass range which is kinematically long lived. Due interactions, such a can thermally produced early Universe followed by decoupling while being relativistic. The final relic abundance typically...

We consider the possibility of probing left-right symmetric model (LRSM) via cosmic microwave background (CMB). adopt minimal LRSM with Higgs doublets, also known as doublet (DLRM), where all fermions including neutrinos acquire masses only their couplings to bidoublet. Due Dirac nature light neutrinos, there exist additional relativistic degrees freedom which can thermalise in early universe by virtue gauge interactions corresponding right sector. constrain from Planck 2018 bound on...

The existence of prolonged radiation domination prior to the Big Bang Nucleosynthesis (BBN), starting just after inflationary epoch, is not yet established unanimously. If instead, universe undergoes a non-standard cosmological phase, it will alter Hubble expansion rate significantly and may also generate substantial entropy through non-adiabatic evolution. This leads thumping impact on properties relic species decoupled from thermal bath before revival standard in vicinity BBN. In this...

Abstract In this paper, we construct a viable model for GeV scale self-interacting dark matter (DM), where the DM was thermally produced in early universe. Here, new vector-like fermion with charge under U(1)_D gauge symmetry serves as secluded WIMP and it can dominantly annihilate into light boson singlet scalar through interaction. Also, self-interaction of is induced by via same addition to these particles, further introduce two Weyl fermions doublet scalar, which from s-wave...

We propose a minimal extension of the standard model particle physics to accommodate cosmic inflation, dark matter and light neutrino masses. While inflationary phase is obtained from modified chaotic inflation scenario, consistent with latest cosmology data, fermion singlet which remains out equilibrium in early universe. The scalar field revives scenario by suitable modification also assists generating tiny couplings its mother particle, naturally realizing non-thermal or freeze-in type...

We propose a type II seesaw model for light Dirac neutrinos to provide an explanation the recently reported anomaly in W boson mass by CDF collaboration with $7σ$ statistical significance. In minimal model, required enhancement is obtained at tree level due vacuum expectation value of real scalar triplet, which also plays role generating neutrino mass. Depending upon couplings and masses newly introduced particles, we can have thermally or non-thermally generated relativistic degrees freedom...

The addition of a Higgs quadruplet to the standard model (SM) quarks and leptons would shift <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>W</a:mi></a:math>-boson mass upward. It could also facilitate production dark matter through conventional thermal freeze-out scenario via Yukawa interaction with or freeze-in from decay SM Higgs. We investigate same-sign lepton smoking gun signature double-charged scalar component at LHC. Published by American Physical Society 2024

A bstract 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 one-loop mass, anomalous magnetic moment muon: ( g − 2) μ as well additional relativistic degrees freedom ∆ N eff within reach cosmic microwave background (CMB) experiments. show that nature neutrinos can bring interesting correlations parameter space satisfying , DM relic density and effective . While we stick to thermal...

We propose a minimal predictive scenario for dark matter and radiative neutrino mass where the relic abundance of is generated from hybrid setup comprising both thermal freeze-out as well non-thermal freeze-in mechanisms. Considering three copies fermion triplets one scalar doublet, odd under an unbroken 2 symmetry, to be responsible origin mass, we consider lightest triplet candidate which remains under-abundant in sub-TeV regime usual freeze-out. Late decay 2-odd doublet into serves...

The dark sector is postulated to be invariant under an SU(2) gauge symmetry, spontaneously broken by a Higgs quadruplet conserved residual Z3×Z2 symmetry. resulting matter phenomenology studied.