arXiv subjects

Neelam Singh

Publications and source records attributed to Neelam Singh.

10 recordsLinked to original sources

arXiv2025

Dark-technicolour at colliders

We demonstrate that QCD-like gauge dynamics can be consistently embedded within the Dark Technicolor paradigm by invoking the extended Most Attractive Channel hypothesis, thereby revitalizing conventional technicolor scenarios. In this framework, the Higgs mass is generated dynamically while remaining consistent with electroweak precision tests, including constraints from the $S$ parameter. The flavor problem is resolved by incorporating the Standard Hierarchical VEVs Model, whereas a simple Froggatt--Nielsen construction is shown to be incompatible. Couplings of techni-hadrons such as $\rho_{\rm TC}$ and $\eta_{\rm TC}^\prime$ to Standard Model fermions are highly suppressed, leading to negligible direct fermionic signatures. Nevertheless, DTC mesons remain testable at the HL-LHC, HE-LHC, and future 100~TeV collider, with promising discovery channels including $\bar{b}b$, $\tau^+\tau^-$, $t\bar{t}$, and $\gamma\gamma$.

hep-ph↗

arXiv2024

Phenomenology of the standard HVM and 95.4 GeV excess

We investigate the collider phenomenology of the standard Hierarchical VEVs Model by proposing a new version, which avoids large flavor changing neutral current interactions, thus, rendering the scale of new physics as low as the electroweak scale. The resulting collider signatures are distinctive and testable at the High-Luminosity LHC, the High-Energy LHC, and future 100\,TeV hadron colliders. Remarkably, one of the pseudoscalars in the model can account for the 95.4\,GeV di-photon excess observed by ATLAS and CMS. In addition, the model naturally accommodates a new class of neutrino-philic dark matter candidate, \emph{neutrinic dark matter}, that interacts exclusively with neutrino pairs.

hep-ph↗

arXiv2024

Finding flavons at colliders

We conduct a comprehensive investigation into the flavour phenomenology and collider signatures of flavon of $\mathcal{Z}_{\rm N} \times \mathcal{Z}_{\rm M}$ flavour symmetries for the soft symmetry-breaking scenario and a new symmetry-conserving mechanism at the high-luminosity LHC, high energy LHC, and a 100 TeV hadron collider. The flavour physics of quark and leptonic observables places different bounds on the parameter space of flavons of $\mathcal{Z}_{\rm N} \times \mathcal{Z}_{\rm M}$ flavour symmetries. On the collider side, the decay $t \rightarrow c a$ can be probed by the high-luminosity LHC, high energy LHC, and a 100 TeV hadron collider for the $\mathcal{Z}_{\rm 8} \times \mathcal{Z}_{\rm 22}$ flavour symmetry. The inclusive production signatures can be used to probe the flavon of all the $\mathcal{Z}_{\rm N} \times \mathcal{Z}_{\rm M} $ flavour symmetries for the soft symmetry-breaking scenario for a heavy flavon at a 100 TeV collider. Flavons of all the $\mathcal{Z}_{\rm N} \times \mathcal{Z}_{\rm M} $ flavour symmetries can be probed at high energy LHC and a 100 TeV collider for a low mass in the case of soft symmetry-breaking. The di-flavon production is within reach of the high-luminosity LHC, high energy LHC, and a 100 TeV collider only for a light flavon. The 14 TeV high-luminosity LHC can probe only the $\mathcal{Z}_{\rm 2} \times \mathcal{Z}_{\rm 5}$ and $\mathcal{Z}_{\rm 8} \times \mathcal{Z}_{\rm 22}$ flavour symmetries for a few specific inclusive signatures. The symmetry-conserving scenario remains beyond the detection capabilities of any collider.

hep-ph↗

arXiv2024

Discrete origins of matter

We discuss models of the flavour problem and dark matter based on the discrete $\mathcal{Z}_{\rm N} \times \mathcal{Z}_{\rm M} \times \mathcal{Z}_{\rm P}$ flavour symmetry. A new class of dark-matter emerges out of these models, which is defined as the flavonic dark matter. An ultra-violet completion of these models based on the dark-technicolour paradigm is also presented.

hep-ph↗

arXiv2024

Renormalization-group improved Higgs to two gluons decay rate

We investigate the renormalization-group scale and scheme dependence of the $H \rightarrow gg$ decay rate at the order N$^4$LO in the renormalization-group summed perturbative theory, which employs the summation of all renormalization-group accessible logarithms including the leading and subsequent four sub-leading logarithmic contributions to the full perturbative series expansion. Moreover, we study the higher-order behaviour of the $H \rightarrow gg$ decay width using the asymptotic Padé approximant method in four different renormalization schemes. Furthermore, the higher-order behaviour is independently investigated in the framework of the asymptotic Padé-Borel approximant method where generalized Borel-transform is used as an analytic continuation of the original perturbative expansion. The predictions of the asymptotic Padé-Borel approximant method are found to be in agreement with that of the asymptotic Padé approximant method. Finally, we provide the $H \rightarrow gg$ decay rate at the order N$^5$LO in the fixed-order $ Γ_{\rm N^5LO} \,=\, Γ_0 (1.8375 \pm 0.047 _{α_s(M_Z),1\%}\pm 0.0004_{M_t} \pm 0.0066_{M_H} \pm 0.0036_{\rm P} \pm 0.007_{\text{s}} \pm 0.0005_{sc} ),$ and $Γ_{\rm RGSN^5LO} \,=\, Γ_0 (1.841 \pm 0.047 _{α_s(M_Z),1\%} \pm 0.0005_{M_t}\pm 0.0066_{M_H} \pm 0.0002_μ \pm 0.0027_{\rm P} \pm 0.001_{sc} )$ in the renormalization-group summed perturbative theories.

hep-ph↗

arXiv2023

Dark-technicolour at low scale

We discuss a low-scale realization of the dark-technicolour paradigm, where the dark-technicolour scale is close to the electroweak scale. This scenario provides an ultraviolet completion of the standard HVM, and predicts a dark-Higgs with mass $ m_{\rm DH } = 95.4$ GeV. Moreover, the grand-unification scale in this framework can be as low as $1.18 \times 10^8$ GeV.

hep-ph↗

arXiv2023

The problem of flavour

We review the problem of flavour tracing back to the days when the standard model was just coming together. We focus on the recently discussed new solutions of this problem, namely the Froggatt and Nielsen mechanism based on a novel discrete $\mathcal{Z}_{\rm N} \times \mathcal{Z}_{\rm M}$ flavour symmetry, and the standard hierarchical VEVs model. The standard HVM, and the Froggatt and Nielsen mechanism based on the $\mathcal{Z}_{\rm N} \times \mathcal{Z}_{\rm M}$ flavour symmetry, can be recovered from a new dark-technicolour paradigm, where the hierarchical VEVs or the flavon VEV may appear as the chiral multifermion condensates. In particular, there appears a novel feature that the solution of the flavour problem based on the discrete flavour symmetry can provide the so-called flavonic dark matter. This predicts a specific relation between the mass and the symmetry-breaking scale, which can be contrasted with the standard QCD axion. Moreover, a possible direction towards the Grand Unified framework is also discussed.

hep-ph↗

arXiv2023

Flavour bounds on the flavon of a minimal and a non-minimal $\mathcal{Z}_2 \times \mathcal{Z}_N$ symmetry

We investigate flavour bounds on the $\mathcal{Z}_2 \times \mathcal{Z}_5$ and $\mathcal{Z}_2 \times \mathcal{Z}_9$ flavour symmetries. These flavour symmetries are a minimal and a non-minimal forms of the $\mathcal{Z}_2 \times \mathcal{Z}_N$ flavour symmetry, that can provide a simple set-up for the Froggatt-Nielsen mechanism. The $\mathcal{Z}_2 \times \mathcal{Z}_5$ and $\mathcal{Z}_2 \times \mathcal{Z}_9$ flavour symmetries are capable of explaining the fermionic masses and mixing pattern of the standard model including that of the neutrinos. The bounds on the parameter space of the flavon field of the $\mathcal{Z}_2 \times \mathcal{Z}_5$ and $\mathcal{Z}_2 \times \mathcal{Z}_9$ flavour symmetries are derived using the current quark and lepton flavour physics data and future projected sensitivities of quark and lepton flavour effects. The strongest bounds on the flavon of the $\mathcal{Z}_2 \times \mathcal{Z}_5$ symmetry come from the $D^0 - \bar D^0$ mixing. The bounds on the $\mathcal{Z}_2 \times \mathcal{Z}_9$ flavour symmetry are stronger than that of the minimal $\mathcal{Z}_2 \times \mathcal{Z}_5$ symmetry. The ratio $R_{μμ}$ provides rather robust bounds on the flavon parameters in the future phase-\rom{1} and phase-\rom{2} of the LHCb by leaving only a very small region in the allowed parameter space of the models.

hep-ph↗

arXiv2020

Towards Intelligent Reconfigurable Wireless Physical Layer (PHY)

Next-generation wireless networks are getting significant attention because they promise 10-factor enhancement in mobile broadband along with the potential to enable new heterogeneous services. Services include massive machine type communications desired for Industrial 4.0 along with ultra-reliable low latency services for remote healthcare and vehicular communications. In this paper, we present the design of an intelligent and reconfigurable physical layer (PHY) to bring these services to reality. First, we design and implement the reconfigurable PHY via a hardware-software co-design approach on system-on-chip consisting of the ARM processor and field-programmable gate array (FPGA). The reconfigurable PHY is then made intelligent by augmenting it with online machine learning (OML) based decision-making algorithm. Such PHY can learn the environment (for example, wireless channel) and dynamically adapt the transceivers' configuration (i.e., modulation scheme, word-length) and select the wireless channel on-the-fly. Since the environment is unknown and changes with time, we make the OML architecture reconfigurable to enable dynamic switch between various OML algorithms on-the-fly. We have demonstrated the functional correctness of the proposed architecture for different environments and word-lengths. The detailed throughput, latency, and complexity analysis validate the feasibility and importance of the proposed intelligent and reconfigurable PHY in next-generation networks.

eess.SY↗

arXiv2020

Unique photoluminescence response of MoS2 quantum dots over wide range of As (III) in aqueous media

Solvothermal synthesis of MoS2 based quantum dots (QDs) and the performance evaluation of bare QDs for the detection of aqueous As (III) oxidative state at room temperature and neutral pH over an extremely wide range (0.1 ppb to 1000 ppb) is reported here. Concentration-dependent photoluminescence (PL) of the QDs was found to be enhanced up to 50 ppb and then suppressed till 1000 ppb, showing two distinctive slopes for enhancement and suppression. Passivation of trap states or defects of QDs may be the possible reason for enhancement, and the formation of extremely small glassy As2S3 particles on the QD surface may be the possible reason for suppression. The pattern of optical absorption of QDs is featureless but shows an enhanced absorbance in the near UV range below 300 nm, which increases with As (III) concentration up to 50 ppb and then decreases following the PL pattern. The MoS2 QDs were characterized by transmission electron microscopy (TEM), Xray diffraction (XRD), UV-Vis, and PL spectroscopy. The enhancement and suppression results can be fitted excellently with the modified Stern-Volmer equation, and the detection of arsenic is possible using these linear fit equations as calibration curves.

physics.app-ph↗