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Gulsheen Ahuja

Publications and source records attributed to Gulsheen Ahuja.

At least 19 recordsLinked to original sources
arXiv2024

Probing 4 X 4 quark mixing matrix

Without adhering to any specific model, we have presented 4 X 4 quark mixing matrix as an extension of the 3 X 3 PDG parametrization of the CKM matrix. Using unitarity constraints as well as the hierarchy among the elements of the 3 X 3 CKM matrix, we have found the hierarchy among the 4th row and 4th column elements of the 4 X 4 quark mixing matrix. Further, for the fourth generation case, we have explicitly found the 9 independent rephasing invariant parameters J_4X4. Also, using phenomenological estimates of the 4th row and 4th column elements, we have numerically evaluated these 9 parameters.

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arXiv2024

Hierarchy of CKM matrix elements and implications of unitarity

The hierarchy amongst the CKM matrix elements, highlighted recently by Luo and Xing, has been rigorously revisited using the PDG parameterization incorporating unitarity constraints. Further, we have explored the evaluation of the CP violating parameter ε_k for the 9 possible unitarity ensured equivalent independent parametrizations of CKM matrix. Interestingly, we find that not all of these reproduce the value of parameter ε_k, this being presumably due to the hierarchical nature of the CKM matrix elements. This situation is echoing similar conclusions regarding the evaluation of Jarlskog's rephasing invariant parameter J through unitarity ensured equivalent possibilities.

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arXiv2024

Revisiting representations of quark mixing matrix

Using unitarity, unlike the approaches available in the literature, we have constructed 9 independent representations of CKM matrix starting with each of the 9 elements of the matrix. The relationship of these independently constructed representations with the already available ones in the literature has been compared and discussed. Further, the implications of these representations have been explored for some of the CKM parameters such as δ, J and ε_k. Interestingly, we find that the PDG representation which is equivalent to our first representation seems to be most appropriate to incorporate the hierarchy of the elements of the CKM matrix as well as to describe the related phenomenology.

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arXiv2021

Probing texture 4 zero quark mass matrices in the era of precision measurements

In pursuance of finding a viable set of mass matrices, keeping in mind recent precision measurement of quark masses and CKM parameters, we have carried out a detailed and comprehensive analysis of hermitian texture 4 zero quark mass matrices. Our analysis reveals that only Fritzsch like texture 4 zero combination provides a viable set of mass matrices for the present quark mixing data and all other texture 4 zero combinations are ruled out. A good number of these possibilities can be ruled out analytically, the other possibilities are excluded by the present quark mixing data. Interestingly, our conclusions remain valid, even if in future there are perturbations in the ranges of the light quark masses or CKM parameters.

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arXiv2020

Going beyond the minimal texture of quark mass matrices in the era of precision measurements

An attempt has been made to carry out a detailed analysis of quark mass matrices having structure beyond the minimal texture. In particular, keeping in mind, precision measurements of CKM parameters as well as refinements in the ranges of light quark masses, we have examined the viability of all possible combinations of hermitian texture 5 zero quark mass matrices. Interestingly, one finds that all these possibilities are now excluded by the present quark mixing data, thereby, having important implications for model building.

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arXiv2019

Minimal texture of quark mass matrices and precision CKM measurements

We have carried out an extensive analysis of all possible minimal texture quark mass matrices implying 169 texture 6 zero combinations. One finds that all these combinations are ruled out, a good number of these analytically, the other possibilities are excluded by the present quark mixing data. Interestingly, even if in future, there are changes in the ranges of the light quark masses, these conclusions remain valid.

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arXiv2016

Fermion mass matrices, textures and beyond

The issue of texture specific fermion mass matrices have been examined briefly from the `bottom-up' perspective. In case no conditions are imposed, the texture ansatze leads to a large number of viable possibilities. However, besides textures, if in case one incorporates the ideas of `natural mass matrices' and uses the facility of Weak Basis Transformations, then one is able to arrive at a minimal finite set of viable mass matrices in the case of quarks.

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arXiv2016

General lepton textures and their implications

The present work attempts to provide an overview of texture specific lepton mass matrices. In particular, we summarize the findings of some recent analyses carried out within non flavor basis, wherein a parallel texture structure for the lepton and neutrino mass matrices is considered.

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arXiv2016

Revisiting the texture zero neutrino mass matrices

In the light of refined and large reactor mixing angle $θ_{13}$, we have revisited the texture three and two zero neutrino mass matrices in the flavor basis. For Majorana neutrinos, it has been explicitly shown that all the texture three zero mass matrices remain ruled out. Further, for both normal and inverted mass ordering, for the texture two zero neutrino mass matrices one finds interesting constraints on the Dirac-like CP violating phase $δ$ and Majorana phases $ρ$ and $σ$.

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arXiv2015

Minimal Set of Texture Specific Quark Mass Matrices

Starting with the most general mass matrices, within the context of Standard Model and some of its extensions, incorporating the ideas of weak basis transformations and naturalness, we find that there exists a particular set of texture specific quark mass matrices which can be considered to be the minimal viable option.

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arXiv2015

Finding a unique texture for quark mass matrices

Within the Standard Model, starting with the most general mass matrices we have used the facility of making weak basis transformations and have imposed the condition of `naturalness' to carry out their analysis within the texture zero approach. Interestingly, our analysis reveals that a particular set of texture 4 zero quark mass matrices can be considered to be a unique viable option for the description of quark mixing data.

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arXiv2014

Clues towards unified textures

The issue of texture specific mass matrices has been discussed by incorporating Weak Basis transformations and the concept of `naturalness'. Interestingly, we find that starting from the most general mass matrices, one can arrive at texture four zero mass matrices which can fit both quark as well as lepton mixing data and are similar to the original Fritzsch ansatze.

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arXiv2014

Majorana neutrinos and non minimal lepton mass textures

In the light of the recent measurement of the leptonic mixing angle $θ_{13}$, implications of the latest mixing data have been investigated for non-minimal textures of lepton mass matrices assuming the neutrinos to be Majorana like. Large number of possible texture specific lepton mass matrices have been examined for their compatibility with the lepton mixing data in the case of normal hierarchy, inverted hierarchy and degenerate scenario of neutrino masses. Specifically, apart from other phenomenological quantities the implications of the lepton mixing angle $θ_{13}$ have been investigated on the lightest neutrino mass as well as the effective Majorana mass $ $.

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arXiv2014

Implications of non minimal lepton mass textures for Dirac neutrinos

In the light of the recent measurement of the leptonic mixing angle $θ_{13}$, implications of the latest mixing data have been investigated for non-minimal textures of lepton mass matrices pertaining to Dirac neutrinos. All these texture specific lepton mass matrices have been examined for their compatibility with the latest data in the cases of normal hierarchy, inverted hierarchy and degenerate scenario of neutrino masses. The implications of all the three lepton mixing angles have been investigated on the lightest neutrino mass as well as the Jarlskog's CP violating parameter in the leptonic sector.

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arXiv2014

Leptonic mixing angle $θ_{13}$ and ruling out of minimal texture for Dirac neutrinos

Implications of recently measured leptonic mixing angle $θ_{13}$ as well as the other two mixing angles have been examined for Fritzsch-like mass matrices with minimal texture for Dirac neutrinos. Interestingly, the existing data seems to rule out this texture specific case of Dirac neutrinos for normal, inverted hierarchy as well as degenerate scenario of masses.

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arXiv2013

Flavor mixings and textures of the fermion mass matrices

A comprehensive review of several aspects of fermion mixing phenomenon and texture specific mass matrices have been presented. Regarding fermion mixings, implications of unitarity and certain new developments for the CKM paradigm have been discussed. In the leptonic sector, the question of possibility of CP violation has been discussed in detail from the unitarity triangle perspective. In the case of texture specific mass matrices, the issues of viability of Fritzsch-like as well as non Fritzsch-like mass matrices have been detailed for both the quark and leptonic sectors. The relationship of textures, naturalness and weak basis rotations has also been looked into. The issue of the compatibility of texture specific mass matrices with the SO(10) based GUT mass matrices has also been discussed.

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arXiv2013

Implications of theta_13 on Fritzsch-like lepton mass matrices

Implications of the lepton mixing angles, in particular of theta_13, have been investigated for minimal as well as non-minimal Fritzsch-like textures for the case of Majorana neutrinos. Both, in minimal texture (texture 6 zero lepton mass matrices) and non-minimal textures (two cases of texture 5 zero lepton mass matrices), inverted hierarchy and degenerate scenario of neutrino masses have been ruled out. The implications of theta_13 have been investigated on the lightest neutrino mass m_ν_1 as well as the effective Majorana mass m_ee.

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