arXiv subjects

Gazal Sharma

Publications and source records attributed to Gazal Sharma.

8 recordsLinked to original sources

arXiv2026

Minimal Quark-Lepton Complementarity from a Rigid Deformation of Tri-Bimaximal Mixing

We propose a minimal three-family realization of quark--lepton complementarity (QLC) in which the non-trivial correlation matrix is an exactly unitary, rigid deformation of tri-bimaximal mixing. In a canonical TBM convention the deformation is a rotation about the normalized axis $n_{gg}=(2,1,2)^T/3$, with rotation angle fixed by the Cabibbo angle, $\alpha_{gg}=-3\theta_C/4$. The resulting ansatz, $\UPMNS=\VCKM^\dagger\UTBM R_{n_{gg}}(-3\theta_C/4)$, contains no new continuous parameter in the Dirac lepton-mixing sector once the structural choice is fixed. With the 2025 Particle Data Group CKM fit it predicts $\theta_{12}=33.29^\circ$, $\theta_{13}=8.46^\circ$, $\theta_{23}=49.19^\circ$, and $\dcp=180.79^\circ$, with CKM-induced uncertainties much smaller than present oscillation errors. We derive leading Wolfenstein sum rules; in particular, the real deformation preserves the CKM-induced suppression $\Jcp=-A\eta\lambda^3/6+\mathcal O(\lambda^4)$ and hence a near-CP-conserving phase. A retrospective simplicity scan shows that the pair $(2,1,2),3/4$ ranks first among 5510 oriented primitive-integer/rational candidates when tested on epoch-matched 2016 and 2018 oscillation data. In an enlarged 49,622-candidate 2018 scan it is second in raw score but remains first among candidates no more complex than itself under several independent simplicity measures; profiling the rotation strength for the fixed $(2,1,2)$ axis gives $r_{\rm BF}=0.74941$. We formulate the deformation by a convention-covariant flavor-space generator and give an exact effective eigenframe realization $M_\nu=A I+B\Sgg+C\Sgg^2$. The construction is presently allowed in normal ordering, with the atmospheric sector providing its strongest pressure; its upper-octant atmospheric angle and near-$\pi$ Dirac phase provide sharp falsifiability targets.

hep-ph↗

arXiv2026

Revisiting Quark-Lepton Complementarity in the Precision Neutrino Era

We revisit three-generation quark-lepton complementarity in the non-trivial correlation-matrix formulation using the 2026 Particle Data Group quark-mixing inputs and the NuFIT 6.1 oscillation likelihood release. First, we perform a retrospective test of the narrow atmospheric-angle prediction published in 2016. Its central value receives likelihood penalties of 17.99 and 20.43 for normal and inverted ordering, respectively, whereas later ordering-dependent predictions lie close to the current likelihood minima. We then reconstruct a projection-weighted ensemble of the full complex correlation matrix, retaining unrestricted quark-lepton mismatch phases and exact sample-wise unitarity. The first row remains comparatively stable, while the lower two rows account for about 99% of the decade-long mean-texture evolution. The strongest normal-inverted differences occur in the third-row elements, with distribution-overlap coefficients of about 0.41 and 0.42 for the first two entries. Approximately 72% of the present ensemble remains closer to a tribimaximal than to a bimaximal reference texture. The results show that the broad quark-lepton correlation structure is substantially more persistent than the most restrictive atmospheric-angle prediction derived from it.

hep-ph↗

arXiv2019

Investigating Sterile Neutrino Flux in the Solar Neutrino Data

There are compelling evidences for the existence of a fourth degree of freedom of neutrinos i.e. sterile neutrino. In the recent studies the role of sterile component of neutrinos has been found to be crucial, not only in particle physics, but also in astrophysics and cosmology. This has been proposed to be one of the potential candidates of dark matter. In this work we investigate the updated solar neutrino data available from all the relevant experiments including Borexino and KamLAND solar phase in a model independent way, and obtain bounds on the sterile neutrino component present in the solar neutrino flux. The mystery of the missing neutrinos is further deepening as subsequent experiments are coming up with their results. The energy spectrum of solar neutrinos, as predicted by Standard Solar Models (SSM), is seen by neutrino experiments at different parts as they are sensitive to various neutrino energy ranges. It is interesting to note that more than $98\%$ of the calculated standard model solar neutrino flux lies below $1MeV$. Therefore, the study of low energy neutrinos can give us better understanding and the possibility to know about the presence of antineutrino and sterile neutrino components in solar neutrino flux. As such, this work becomes interesting as we include the data from medium energy ($\sim 1MeV$) experiments i.e. Borexino and KamLAND solar phase. In our study we retrieve the bounds existing in literature, and rather provide more stringent limits on sterile neutrino($ν_{s}$) flux available in solar neutrino data.

hep-ph↗

arXiv2019

CP-Violation phase analysis via non-trivial correlation of quarks and leptons in 3+1 scenario

The existence and mysterious nature of sterile neutrinos are revolutionizing physics from the particle level to the cosmological scales. The recent results from the MiniBooNE experiment at Fermi-lab observed far more $ν_{e}$ appearance than expected, which have provided a hint about the possible existence of \textit{sterile neutrinos}. The results, if confirmed in future experiments, will have significant implications for cosmology and astroparticle physics. This will require new neutrino mass models to accommodate these additional degrees of freedom. In respect to that, the present work is just an extension of our recent work towards the CP phase analysis of Quark-lepton complementarity(QLC) model in a 3+1 scenario. The parametrization of $CKM_{4}$ and $PMNS_{4}$ using Monte Carlo Simulation is used to estimate the texture of non-trivial correlation matrix ($V_{c_{4}}$). As such, we have successfully investigated the constrained values for sterile neutrino parameters, and also predicted the values for Dirac CP-Violation phase and the CP re-phasing invariant (J). The results obtained are consistent with the data available from various experiments, like No$ν$A, MINOS, SuperK and IceCube-DeepCore. Furthermore, this analysis would be very important in view of growing sterile neutrino experiments.

hep-ph↗

arXiv2019

Investigating the sterile neutrino parameters with QLC in 3 + 1 scenario

In the scenario with four generation quarks and leptons and using a 3 + 1 neutrino model having one sterile and the three standard active neutrinos with a $4 \times 4$ unitary transformation matrix, $U_{PMNS_{4}}$, we perform a model-based analysis using the latest global data and determine bounds on the sterile neutrino parameters i.e. the neutrino mixing angles. Motivated by our previous results, where, in a quark-lepton complementarity (QLC) model we predicted the values of $θ_{13}^{PMNS}=(9_{-2}^{+1})^{\circ}$ and $θ_{23}^{PMNS}=(40.60_{-0.3}^{+0.1})^{\circ}$. In the QLC model the non-trivial correlation between $CKM_4$ and $PMNS_4$ mixing matrix is given by the correlation matrix $V_{c_{4}}$. Monte Carlo simulations are performed to estimate the texture of $V_{c4}$ followed by the calculation of $PMNS_4$ using the equation, $U_{PMNS_{4}}= (U_{CKM_{4}} . ψ_{4})^{-1}.V_{c_{4}}$, where $ψ_{4}$ is a diagonal phase matrix. The sterile neutrino mixing angles, $θ_{14}^{PMNS}$, $θ_{24}^{PMNS}$ and $θ_{34}^{PMNS}$ are assumed to be freely varying between $(0-π/4)$ and obtained results which are consistent with the data available from various experiments, like No$ν$A, MINOS, SuperK, Ice Cube-DeepCore. In further investigation, we analytically obtain approximately similar ranges for various neutrino mixing parameters $\mid{ U_{μ4}}\mid ^2$ and $\mid{ U_{τ4}}\mid ^2$.

hep-ph↗

arXiv2018

Quark-lepton complementarity model based predictions for $θ_{23}^{PMNS}$ with neutrino mass hierarchy

After the successful investigation and confirmation of non zero $θ_{13}^{PMNS}$ by various experiments, we are standing at a square where we still encounter a number of issues, which are to be settled. In this paper, we have extended our recent work towards a precise prediction of the $θ_{23}^{PMNS}$ mixing angle, taking into account the neutrino mass hierarchy. We parameterize the non-trivial correlation between quark (CKM) and lepton (PMNS) mixing matrices in quark-lepton complementarity (QLC) model as $V_{c}= U_{CKM}. ψ. U_{PMNS}$, where $ψ$ is a diagonal phase matrix. Monte Carlo simulations are used to estimate the texture of $V_{c}$ and compare the results with the standard Tri-Bi-Maximal (TBM) and Bi-Maximal(BM) structures of neutrino mixing matrix. We have predicted the value of $θ_{23}^{PMNS} $ for normal and inverted neutrino mass hierarchies. The value of $θ_{23}^{PMNS}$ obtained for two cases are about $1.3σ$ away from each other, implying the better precision can give us a strong hint for the type of neutrino mass hierarchy.

hep-ph↗

arXiv2017

Dark Matter and Neutrinos

The Keplerian distribution of velocities is not observed in the rotation of large scale structures, such as found in the rotation of spiral galaxies. The deviation from Keplerian distribution provides compelling evidence of the presence of non-luminous matter i.e. called dark matter. There are several astrophysical motivations for investigating the dark matter in and around the galaxy as halo. In this work we address various theoretical and experimental indications pointing towards the existence of this unknown form of matter. Amongst its constituents neutrino is one of the most prospective candidates. We know the neutrinos oscillate and have tiny masses, but there are also signatures for existence of heavy and light sterile neutrinos and possibility of their mixing. Altogether, the role of neutrinos is of great interests in cosmology and understanding dark matter.

physics.pop-ph↗

arXiv2016

Quark-Lepton Complementarity Predictions for $θ_{23}^{pmns}$ and CP Violation

In the light of recent experimental results on $θ_{13}^{pmns}$, we re-investigate the complementarity between the quark and lepton mixing matrices and obtain predictions for most unsettled neutrino mixing parameters like $θ_{23}^{pmns}$ and CP violating phase invariants $J$, $S_1$ and $S_2$. This paper is motivated by our previous work where in a QLC model we predicted the value for $θ_{13}^{pmns}=(9{^{+1}_{-2}})^\circ$, which was found to be in strong agreement with the experimental results. In the QLC model the non-trivial correlation between CKM and PMNS mixing matrices is given by a correlation matrix ($V_{c}$). We do numerical simulation and estimate the texture of the $V_{c}$ and in our findings we get a small deviation from the Tri-Bi-Maximal (TBM) texture and a large from the Bi-Maximal one, which is consistent with the work already reported in literature. In the further investigation we obtain quite constrained limits for $sin^2{θ_{23}^{pmns}}= 0.4235_{-0.0043}^{+0.0032}$ that is narrower to the existing ones. We also obtain the constrained limits for the three CP violating phase invariants $J$, $S_1$ and $S_2$: as $J < 0.0315$, $S_{1} <0.12$ and $S_{2} <0.08$, respectively.

hep-ph↗