Ranjeet Kumar
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Research Subjects
Ranjeet Kumar has a total of 16 co-authors. Here are the top co-authors by number of shared publications:
- Rahul Srivastava
Department of Physics, Indian Institute of Science Education and Research—Bhopal, Bhopal Bypass Road, Bhauri, Bhopal 462066, India
11 shared publications - Newton Nath
Indian Institute of Technology (BHU)
4 shared publications - Salvador Centelles Chuliá
Instituto de Fisica Corpuscular
3 shared publications - Sushant Yadav
Indian Institute of Science Education and Research - Bhopal
3 shared publications - Gui-Jun Ding
University of Science and Technology of China
2 shared publications - Hemant Prajapati
Indian Institute of Science Education and Research - Bhopal
2 shared publications
Latest Publications
- Open Access
- 2 September 2026
- Published by Springer Nature in The European Physical Journal C
- Vol. 86 (9) , 1037
Zooming in on ‘bi-large’ neutrino mixing with the first JUNO results
The leptonic mixing matrix is examined within bi-large mixing patterns and confronted with the latest results announced by the Jiangmen Underground Neutrino Observatory (JUNO). We analyze the viability of bi-large mixing schemes and assess JUNO’s ability to test neutrino mixing and discriminate among different bi-large mixing patterns, some of which are strongly disfavored when compared with neutrino oscillation global-fit results. Specific octant and CP predictions emerge. Finally, we comment on the implications of JUNO’s findings for neutrinoless double beta decay.
- 2 September 2026
- Published by Springer Nature in The European Physical Journal C
- Vol. 86 (9) , 1037
Open AccessZooming in on ‘bi-large’ neutrino mixing with the first JUNO results
The leptonic mixing matrix is examined within bi-large mixing patterns and confronted with the latest results announced by the Jiangmen Underground Neutrino Observatory (JUNO). We analyze the viability of bi-large mixing schemes and assess JUNO’s ability to test neutrino mixing and discriminate among different bi-large mixing patterns, some of which are strongly disfavored when compared with neutrino oscillation global-fit results. Specific octant and CP predictions emerge. Finally, we comment on the implications of JUNO’s findings for neutrinoless double beta decay.
- Open Access
- 6 May 2026
- Published by American Physical Society (APS) in Physical Review D
- Vol. 113 (9)
Fate of θ 12 under μ − τ reflection symmetry in light of the first JUNO results
The recent Jiangmen Underground Neutrino Observatory (JUNO) measurements of θ 12 and Δ m 21 2 open a new avenue for probing flavor symmetric structures in the lepton sector. Motivated by this, we study a model in which μ − τ reflection symmetry naturally emerges from an underlying A 4 flavor symmetry within a type-II seesaw framework. Beyond its standard predictions of θ 23 = 4 5 ° and δ CP = ± π / 2 , the framework yields testable predictions for θ 12 that can be probed by JUNO. Two viable scenarios arise, one predicting sin 2 θ 12 ≳ 0.335 , which is strongly disfavored by the latest JUNO results. Correlations between θ 12 and model parameters further enhance the model’s predictivity. Future measurements at DUNE and T2HK will provide complementary tests of this scenario.
- 6 May 2026
- Published by American Physical Society (APS) in Physical Review D
- Vol. 113 (9)
Open AccessFate of θ 12 under μ − τ reflection symmetry in light of the first JUNO results
The recent Jiangmen Underground Neutrino Observatory (JUNO) measurements of θ 12 and Δ m 21 2 open a new avenue for probing flavor symmetric structures in the lepton sector. Motivated by this, we study a model in which μ − τ reflection symmetry naturally emerges from an underlying A 4 flavor symmetry within a type-II seesaw framework. Beyond its standard predictions of θ 23 = 4 5 ° and δ CP = ± π / 2 , the framework yields testable predictions for θ 12 that can be probed by JUNO. Two viable scenarios arise, one predicting sin 2 θ 12 ≳ 0.335 , which is strongly disfavored by the latest JUNO results. Correlations between θ 12 and model parameters further enhance the model’s predictivity. Future measurements at DUNE and T2HK will provide complementary tests of this scenario.
- Open Access
- 2 April 2026
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2026 (4) , 24
Dark matter induced proton decays
A bstract: We propose a novel theoretical framework in which proton decay is induced by the dark matter. While proton decay requires violation of the B + L symmetry, dark matter stability often relies on the presence of an unbroken symmetry. These seemingly distinct phenomena are unified through the global U(1) B + L symmetry inherent in the Standard Model. Its spontaneous breaking leads to a residual Z 4 symmetry, which ensures dark matter stability and forbids proton decay at tree level. Consequently, proton decay occurs at the one-loop level, mediated by dark sector particles. The proton lifetime is linked with the dark matter, the heavier dark matter mass enhancing proton stability, and vice versa. The $$ \mathcal{O}\left(\textrm{TeV}\right) $$ masses of the mediators remain consistent with current proton lifetime limits, making them accessible to experimental searches. In particular, the leptoquark mediating proton decay, carrying exotic B + L charges, leads to a distinctive signature in collider searches. By intertwining proton decay, dark matter stability, and collider phenomenology, this framework offers distinctive signatures that can be probed in current and future experiments.- 2 April 2026
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2026 (4) , 24
Open AccessDark matter induced proton decays
A bstract: We propose a novel theoretical framework in which proton decay is induced by the dark matter. While proton decay requires violation of the B + L symmetry, dark matter stability often relies on the presence of an unbroken symmetry. These seemingly distinct phenomena are unified through the global U(1) B + L symmetry inherent in the Standard Model. Its spontaneous breaking leads to a residual Z 4 symmetry, which ensures dark matter stability and forbids proton decay at tree level. Consequently, proton decay occurs at the one-loop level, mediated by dark sector particles. The proton lifetime is linked with the dark matter, the heavier dark matter mass enhancing proton stability, and vice versa. The $$ \mathcal{O}\left(\textrm{TeV}\right) $$ masses of the mediators remain consistent with current proton lifetime limits, making them accessible to experimental searches. In particular, the leptoquark mediating proton decay, carrying exotic B + L charges, leads to a distinctive signature in collider searches. By intertwining proton decay, dark matter stability, and collider phenomenology, this framework offers distinctive signatures that can be probed in current and future experiments. - Open Access
- 13 March 2026
- Published by American Physical Society (APS) in Physical Review D
- Vol. 113 (5)
Minimal A 4 type-II seesaw realization of testable neutrino mass sum rules
We propose a flavor model based on an A 4 symmetry combined with a type-II seesaw mechanism for neutrino mass generation. The resulting neutrino mass matrix obeys a sum rule that, together with the measured mass-squared differences, fully determines the absolute neutrino mass spectrum. The constrained flavor structure yields correlated predictions for lepton mixing parameters, leads to inverted ordering after imposing mixing constraints, restricts the Majorana phases and implies a neutrinoless double beta decay rate close to its maximal value for inverted ordering. In the charged lepton sector an approximate triality symmetry arises in the seesaw limit, suppressing muon flavor-violating processes and allowing only specific τ decay channels. The model provides a tightly constrained and experimentally testable framework linking neutrino masses, lepton mixing, and lepton-number-violating observables.
- 13 March 2026
- Published by American Physical Society (APS) in Physical Review D
- Vol. 113 (5)
Open AccessMinimal A 4 type-II seesaw realization of testable neutrino mass sum rules
We propose a flavor model based on an A 4 symmetry combined with a type-II seesaw mechanism for neutrino mass generation. The resulting neutrino mass matrix obeys a sum rule that, together with the measured mass-squared differences, fully determines the absolute neutrino mass spectrum. The constrained flavor structure yields correlated predictions for lepton mixing parameters, leads to inverted ordering after imposing mixing constraints, restricts the Majorana phases and implies a neutrinoless double beta decay rate close to its maximal value for inverted ordering. In the charged lepton sector an approximate triality symmetry arises in the seesaw limit, suppressing muon flavor-violating processes and allowing only specific τ decay channels. The model provides a tightly constrained and experimentally testable framework linking neutrino masses, lepton mixing, and lepton-number-violating observables.
- Open AccessRadiative Dirac Neutrino Masses from Modular $S_3$ Symmetry in an Axion ModelWe present a unified axion model framework that simultaneously addresses the origin of neutrino masses, leptonic flavor structure, the strong CP problem, and dark matter. The model is based on a global $U(1)_{\rm PQ}$ symmetry combined with a modular $S_3$ symmetry and is realized within a novel class of KSVZ-type axion model. Exotic colored fermions and scalars mediate radiative neutrino mass generation at the one loop-level. The PQ charge assignment forbids tree-level neutrino masses and leaves a residual $Z_3$ symmetry that ensures the Dirac nature of neutrinos. In the minimal realization, the neutrino mass matrix is of rank two, predicting one massless neutrino. Consequently, the sum of neutrino masses is constrained for both the normal and inverted hierarchies. We analyze the implications for charged lepton flavor violation and the lepton $g-2$. The axion emerging from this framework dynamically resolves the strong CP problem and accounts for the observed dark matter abundance. Notably, the predicted axion-photon coupling is within reach of upcoming experiments and consistent with existing astrophysical and cosmological bounds.Open AccessRadiative Dirac Neutrino Masses from Modular $S_3$ Symmetry in an Axion ModelWe present a unified axion model framework that simultaneously addresses the origin of neutrino masses, leptonic flavor structure, the strong CP problem, and dark matter. The model is based on a global $U(1)_{\rm PQ}$ symmetry combined with a modular $S_3$ symmetry and is realized within a novel class of KSVZ-type axion model. Exotic colored fermions and scalars mediate radiative neutrino mass generation at the one loop-level. The PQ charge assignment forbids tree-level neutrino masses and leaves a residual $Z_3$ symmetry that ensures the Dirac nature of neutrinos. In the minimal realization, the neutrino mass matrix is of rank two, predicting one massless neutrino. Consequently, the sum of neutrino masses is constrained for both the normal and inverted hierarchies. We analyze the implications for charged lepton flavor violation and the lepton $g-2$. The axion emerging from this framework dynamically resolves the strong CP problem and accounts for the observed dark matter abundance. Notably, the predicted axion-photon coupling is within reach of upcoming experiments and consistent with existing astrophysical and cosmological bounds.
- Open Access
Zooming in on `bi-large' neutrino mixing with the first JUNO results
The leptonic mixing matrix is examined within bi-large mixing patterns and confronted with the latest results announced by the Jiangmen Underground Neutrino Observatory (JUNO). We analyze the viability of bi large mixing schemes and assess JUNO's ability to test neutrino mixing and discriminate among different bi-large mixing patterns, some of which are strongly disfavored when compared with neutrino oscillation global-fit results. Specific octant and CP predictions emerge. Finally, we comment on the implications of JUNO's findings for neutrinoless double beta decay.
Open AccessZooming in on `bi-large' neutrino mixing with the first JUNO results
The leptonic mixing matrix is examined within bi-large mixing patterns and confronted with the latest results announced by the Jiangmen Underground Neutrino Observatory (JUNO). We analyze the viability of bi large mixing schemes and assess JUNO's ability to test neutrino mixing and discriminate among different bi-large mixing patterns, some of which are strongly disfavored when compared with neutrino oscillation global-fit results. Specific octant and CP predictions emerge. Finally, we comment on the implications of JUNO's findings for neutrinoless double beta decay.
- Open Access
- 17 November 2025
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2025 (11) , 94
Flavor imprints on novel low mass dark matter
A bstract: We present a Majorana scotogenic-like loop framework in which neutrino mass generation and dark matter stability are intrinsically connected to the breaking of the discrete flavor symmetry A 4 . This breaking leads to the emergence of the scoto-seesaw mechanism and a Z 2 symmetry. This naturally explains the solar and atmospheric mass-squared differences, $$ \Delta {m}_{\textrm{sol}}^2 $$ and $$ \Delta {m}_{\textrm{atm}}^2 $$ , while simultaneously ensuring dark matter stability. Our model accommodates normal ordering of neutrino masses, with a generalized μ - τ reflection symmetry shaping the structure of leptonic mixing and a lower limit on the lightest neutrino mass. Moreover, the model provides predictions for the octant of θ 23 and a strong correlation between $$ \Delta {m}_{\textrm{sol}}^2 $$ and $$ \Delta {m}_{\textrm{atm}}^2 $$ . This correlation puts a lower bound on the fermionic DM mass. In contrast, scalar dark matter remains viable over a broad mass spectrum. A notable feature is that the low mass regime (~ 15 GeV onwards) survives owing to the presence of efficient co-annihilation channels, which are typically absent in the Majorana scotogenic scenario. Additionally, the model aligns with current and future limits from lepton flavor violation experiments.- 17 November 2025
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2025 (11) , 94
Open AccessFlavor imprints on novel low mass dark matter
A bstract: We present a Majorana scotogenic-like loop framework in which neutrino mass generation and dark matter stability are intrinsically connected to the breaking of the discrete flavor symmetry A 4 . This breaking leads to the emergence of the scoto-seesaw mechanism and a Z 2 symmetry. This naturally explains the solar and atmospheric mass-squared differences, $$ \Delta {m}_{\textrm{sol}}^2 $$ and $$ \Delta {m}_{\textrm{atm}}^2 $$ , while simultaneously ensuring dark matter stability. Our model accommodates normal ordering of neutrino masses, with a generalized μ - τ reflection symmetry shaping the structure of leptonic mixing and a lower limit on the lightest neutrino mass. Moreover, the model provides predictions for the octant of θ 23 and a strong correlation between $$ \Delta {m}_{\textrm{sol}}^2 $$ and $$ \Delta {m}_{\textrm{atm}}^2 $$ . This correlation puts a lower bound on the fermionic DM mass. In contrast, scalar dark matter remains viable over a broad mass spectrum. A notable feature is that the low mass regime (~ 15 GeV onwards) survives owing to the presence of efficient co-annihilation channels, which are typically absent in the Majorana scotogenic scenario. Additionally, the model aligns with current and future limits from lepton flavor violation experiments. - Open Access
- 10 October 2025
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2025 (10) , 1-33
Dirac Scoto inverse-seesaw from A4 flavor symmetry
A bstract: We present a Dirac scotogenic-like one loop radiative model where the stability of dark matter is intricately linked to the breaking of A 4 flavor symmetry. This breaking induces a $$ {\mathcal{Z}}_2 $$ dark symmetry, stabilizing the dark matter candidate. The breaking of A 4 → $$ {\mathcal{Z}}_2 $$ leads to cutting the loop and facilitating a “scoto inverse-seesaw” mass mechanism responsible for neutrino mass generation. This elucidates the explicit explanation of two mass-squared differences, $$ \Delta {m}_{\textrm{atm}}^2 $$ and $$ \Delta {m}_{\textrm{sol}}^2 $$ observed in neutrino oscillations. Our model accounts for normal and inverted ordering of neutrino masses, revealing sharp correlations between ∑ m i and 〈 m β 〉. It also shows strong compatibility with current data in the δ CP – θ 23 plane. Moreover, stringent constraints on scalar masses narrow down the viable dark matter mass regions, accommodating SU(2) L singlet and doublet scalar dark matter as well as fermionic dark matter. Additionally, our model presents a viable avenue for addressing lepton flavor violating decays while remaining consistent with current experimental constraints.- 10 October 2025
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2025 (10) , 1-33
Open AccessDirac Scoto inverse-seesaw from A4 flavor symmetry
A bstract: We present a Dirac scotogenic-like one loop radiative model where the stability of dark matter is intricately linked to the breaking of A 4 flavor symmetry. This breaking induces a $$ {\mathcal{Z}}_2 $$ dark symmetry, stabilizing the dark matter candidate. The breaking of A 4 → $$ {\mathcal{Z}}_2 $$ leads to cutting the loop and facilitating a “scoto inverse-seesaw” mass mechanism responsible for neutrino mass generation. This elucidates the explicit explanation of two mass-squared differences, $$ \Delta {m}_{\textrm{atm}}^2 $$ and $$ \Delta {m}_{\textrm{sol}}^2 $$ observed in neutrino oscillations. Our model accounts for normal and inverted ordering of neutrino masses, revealing sharp correlations between ∑ m i and 〈 m β 〉. It also shows strong compatibility with current data in the δ CP – θ 23 plane. Moreover, stringent constraints on scalar masses narrow down the viable dark matter mass regions, accommodating SU(2) L singlet and doublet scalar dark matter as well as fermionic dark matter. Additionally, our model presents a viable avenue for addressing lepton flavor violating decays while remaining consistent with current experimental constraints. - 23 March 2025
- Published by Springer Nature
- p. 303-312
Neutrino Mass Sum Rules from Modular $A_4$ Invariance- 23 March 2025
- Published by Springer Nature
- p. 303-312
Neutrino Mass Sum Rules from Modular $A_4$ Invariance- 1 January 2025
- Published by Springer Nature
- p. 407-410
Emergence of Dark Symmetry as Well as Neutrino Mass Scales from $A_4$ Flavor Symmetry- 1 January 2025
- Published by Springer Nature
- p. 407-410
Emergence of Dark Symmetry as Well as Neutrino Mass Scales from $A_4$ Flavor Symmetry