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T. Hussain

Publications and source records attributed to T. Hussain.

At least 19 recordsLinked to original sources

Particle Swarm Optimization Based Analysis to Unlocking the Neutrino Mass Puzzle using $A_{4}\times Z_{3}\times Z_{10}$ Flavor Symmetry

New research has highlighted a shortfall in the Standard Model (SM) because it predicts neutrinos to have zero mass. However, recent experiments on neutrino oscillation have revealed that the majority of neutrino parameters indeed indicate their significant mass. In response, scientists are increasingly incorporating discrete symmetries alongside continuous ones for better justification of observed patterns of neutrino mixing. In this study, we have examined a model within $A_4\times Z_3\times Z_{10}$ symmetry to estimate the neutrino masses using particle swarm optimization technique for both mass hierarchy of neutrino. This model employed a hybrid seesaw mechanism, a combination of seesaw mechanism of type-I and type-II, to establish the effective Majorana neutrino mass matrix. After calculating the mass eigenvalues and lepton mixing matrix upto second order perturbation theory in this framework, this study seeks to investigate the scalar potential for vacuum expectation values (VEVs), optimize the parameters, $U_{PMNS}$ matrix, neutrino masses: $|{m_{1}^{\prime}}^N|=0.0292794-0.0435082\ eV$, $|{m_{2}^{\prime}}^N|=1.78893\times 10^{-18}-0.0293509\ eV$, $|{m_{3}^{\prime}}^N|=0.0307414-0.0471467\ eV$, $|{m_{1}^{\prime}}^I|=0.00982013-0.0453623\ eV$, $|{m_{2}^{\prime}}^I_|=0.0379702-0.0471197\ eV$, and $|{m_{3}^{\prime}}^I|=0.0122063-0.027544\ eV$, effective neutrino mass parameters: $\langle {m_{ee}} \rangle^N=(0.170-3.93)\times10^{-2}\ eV$, $\langle {m_β} \rangle^N=(0.471-1.39)\times10^{-2}\ eV$, $\langle {m_{ee}} \rangle^I=(1.85-4.55)\times10^{-2}\ eV$ and $\langle {m_β} \rangle^I=(2.26-4.56)\times10^{-2}\ eV$, are predicted for both mass hierarchy through particle swarm optimization (PSO), showing strong agreement with recent experimental findings.

hep-ph

$T_7$ Flavor Symmetry gym: The Key to Unlocking the Neutrino Mass Puzzle

Recent research has indicated that the Standard Model (SM), while historically highly effective, is found to be insufficient due to its prediction of zero mass for neutrinos. With the exception of a few, the majority of the parameters related to neutrinos have been determined by neutrino oscillation experiments with excellent precision. Experiments on neutrino oscillation and neutrino mixing have shown that neutrinos are massive. To fill in gaps, discrete symmetries are becoming more common alongside continuous symmetries while describing the observed pattern of neutrino mixing. Here, we present a $T_7$ flavor symmetry to explain the masses of charged leptons and neutrinos. The light neutrino mass matrix is derived using seesaw mechanism of type I, which involves the Dirac neutrino mass matrix as well as the right-handed neutrino mass matrix. We estimate the Pontecorvo-Maki-Nakagawa-Sakata matrix ($U_{PMNS}$), three mixing angles, $θ_{12}$, $θ_{23}$ and $θ_{13}$, which are strongly correlated with the recent experimental results. The extent of $CP$ violation in neutrino oscillations is obtained by calculating Jarskog invariant $(J_{CP})$ on the behalf of $U_{PMNS}$. We also find the masses of three neutrinos and Effective Majorana neutrino mass parameter $\langle m_{ee} \rangle$ which is $1.0960$ $meV$ and $10.9217$ $meV$ for normal and inverted hierarchy, respectively.

hep-ph

SiC/YAG composite coatings by a novel liquid fuelled high velocity oxy-fuel suspension thermal spray

Despite recent advances in suspension-based thermal spray techniques, there is still a need to widen the capability of available thermal spray setups to handle suspension to explore new compositions and improve the properties and performance of existing ones. In this work, a novel setup for injecting liquid-based feedstock in a liquid-fuelled high velocity oxy-fuel (HVOLF) thermal spray torch is proposed, involving a new hardware ("Hybrid Nozzle") capable of injecting suspension radially and protecting the thermal spray flame from the environmental oxygen by inert gas shrouding. The new setup was used to deposit SiC/YAG composite coatings with 85 wt. % SiC content, and their wear performance was evaluated. An oxygen deficient environment was provided to the HVOLF flame, ensuring no or minimal (<2 wt. %) SiO_2 was formed in the coating during the spray, as confirmed by XRD. A good wear performance was observed at low load below 20 N, with a specific wear rate < 5 x 10^-5 mm^3/Nm, with the onset of wear mechanisms characteristic of ceramic wear in the brittle regime between 20 and 30 N. The future applicability of this novel setup to a range of oxidation- and heat-sensitive materials and composites offers the opportunity for new coating materials to be explored with suspension and solution precursor-based HVOLF thermal spray.

physics.app-ph

MALS SALT-NOT survey of MIR-selected powerful radio-bright AGN at 0<z<3.5

We present results of an optical spectroscopic survey using SALT and NOT to build a WISE mid-infrared color-based, dust-unbiased sample of powerful radio-bright ($>$200 mJy at 1.4 GHz) AGN for the MeerKAT Absorption Line Survey (MALS). Our sample has 250 AGN (median $z=1.8$) showing emission lines, 26 with no emission lines, and 27 without optical counterparts. Overall, our sample is fainter ($Δi$=0.6 mag) and redder ($Δ(g-i)$=0.2 mag) than radio-selected quasars, and representative of fainter quasar population detected in optical surveys. About 20% of the sources are narrow line AGN (NLAGN) $-$ 65% of these, at $z < 0.5$ are galaxies without strong nuclear emission, and 10% at $z>1.9$, have emission line ratios similar to radio galaxies. The farthest NLAGN in our sample is M1513$-$2524 ($z_{em}=3.132$), and the largest (size$\sim$330 kpc) is M0909$-$3133 ($z_{em}=0.884$). We discuss in detail 110 AGN at $1.9 < z < 3.5$. Despite representing the radio loudest quasars (median $R$=3685), their Eddington ratios are similar to the SDSS quasars having lower $R$. We detect 4 CIV BALQSOs, all among AGN with least $R$, and highest black hole masses and Eddington ratios. The BAL detection rate ($4^{+3}_{-2}$%) is consistent with that seen in extremely powerful ($L_{1.4GHz}>10^{25}$ WHz$^{-1}$) quasars. Using optical light-curves, radio polarization and $γ$-ray detections, we identify 7 high-probability BL Lacs. We also summarize the full MALS footprint to search for HI 21-cm and OH 18-cm lines at $z<2$.

astro-ph.GA

Enhancement in hydrogen storage capacities of light metal functionalized Boron Graphdiyne nanosheets

The recent experimental synthesis of the two-dimensional (2D)boron-graphdiyne (BGDY) nanosheet has motivated us to investigate its structural, electronic,and energy storage properties. BGDY is a particularly attractive candidate for this purpose due to uniformly distributed pores which can bind the light-metal atoms. Our DFTcalculations reveal that BGDY can accommodate multiple light-metal dopants (Li, Na, K, Ca)with significantly high binding energies. The stabilities of metal functionalized BGDY monolayers have been confirmed through ab initio molecular dynamics simulations. Furthermore, significant charge-transfer between the dopantsand BGDY sheet renders the metal with a significant positive charge, which is a prerequisite for adsorbing hydrogen (H2) molecules with appropriate binding energies.This results in exceptionally high H2 storage capacities of 14.29, 11.11, 9.10 and 8.99 wt% for the Li, Na, K and Ca dopants, respectively. These H2storage capacities are much higher than many 2D materials such as graphene, graphane, graphdiyne, graphyne, C2N, silicene, and phosphorene. Average H2 adsorption energies for all the studied systems fall within an ideal window of 0.17-0.40 eV/H2. We have also performed thermodynamic analysis to study the adsorption/desorption behavior of H2, which confirmsthat desorption of the H2molecules occurs at practical conditions of pressure and temperature.

cond-mat.mes-hall

N-, B-, P-, Al-, As-, Ga-graphdiyne/graphyne lattices: First-principles investigation of mechanical, optical and electronic properties

Graphdiyne and graphyne are carbon-based two-dimensional (2D) porous atomic lattices, with outstanding physics and excellent application prospects for advanced technologies, like nanoelectronics and energy storage systems. During the last year, B- and N-graphdiyne nanomembranes were experimentally realized. Motivated by the latest experimental advances, in this work we predicted novel N-, B-, P-, Al-, As-, Ga-graphdiyne/graphyne 2D lattices. We then conducted density functional theory simulations to obtain the energy minimized structures and explore the mechanical, thermal stability, electronic and optical characteristics of these novel porous nanosheets. Acquired theoretical results reveal that the predicted carbon-based lattices are thermally stable. It was moreover found that these novel 2D nanostructures can exhibit remarkably high tensile strengths or stretchability. The electronic structure analysis reveals semiconducting electronic character for the predicted monolayers. Moreover, the optical results indicate that the first absorption peaks of the imaginary part of the dielectric function for these novel porous lattices along the in-plane directions are in the visible, IR and near-IR (NIR) range of light. This work highlights the outstanding properties of graphdiyne/graphyne lattices and recommends them as promising candidates to design stretchable energy storage and nanoelectronics systems.

physics.comp-ph

Influence of KCl and HCl on a Laser Clad FeCrAl Alloy: In-Situ SEM and Controlled Environment High Temperature Corrosion

Increasing pressure on the power industry to reduce carbon emissions has led to increased research into the use of biomass feedstocks. This work investigates the effects of HCl and KCl, key species influencing biomass boiler corrosion, on a laser clad coating of the FeCrAl alloy Kanthal APMT. In-Situ SEM exposure of the coating at 450 oC for 1 h was performed to investigate the initial effects of KCl on the corrosion process. The same coatings were exposed to 250 h exposures in both an air environment and a HCl rich environment. The influence of KCl was investigated in both. Evidence of a slow growing aluminium oxide was observed. It was found that HCl allowed chlorine based corrosion to occur suggesting it can interact from the gas phase. It was also observed that the presence of both HCl and KCl reduced the mass gain compared to KCl in an air environment.

physics.app-ph

The MeerKAT Absorption Line Survey (MALS)

Deep galaxy surveys have revealed that the global star formation rate (SFR) density in the Universe peaks at 1 < z < 2 and sharply declines towards z = 0. But a clear picture of the underlying processes, in particular the evolution of cold atomic (~100 K) and molecular gas phases, that drive such a strong evolution is yet to emerge. MALS is designed to use MeerKAT's L- and UHF-band receivers to carry out the most sensitive (N(HI)>10$^{19}$ cm$^{-2}$) dust-unbiased search of intervening HI 21-cm and OH 18-cm absorption lines at 0 < z < 2. This will provide reliable measurements of the evolution of cold atomic and molecular gas cross-sections of galaxies, and unravel the processes driving the steep evolution in the SFR density. The large sample of HI and OH absorbers obtained from the survey will (i) lead to tightest constraints on the fundamental constants of physics, and (ii) be ideally suited to probe the evolution of magnetic fields in disks of galaxies via Zeeman Splitting or Rotation Measure synthesis. The survey will also provide an unbiased census of HI and OH absorbers, i.e. cold gas associated with powerful AGNs (>10$^{24}$ W Hz$^{-1}$) at 0 < z < 2, and will simultaneously deliver a blind HI and OH emission line survey, and radio continuum survey. Here, we describe the MALS survey design, observing plan and the science issues to be addressed under various science themes.

astro-ph.GA

Study of $ψ(3686)\toπ^0 h_c, h_c\toγη_c$ via $η_c$ exclusive decays

The process $ψ(3686) \to π^0 h_c, h_c \to γη_c$ has been studied with a data sample of $106 \pm 4$ million $ψ(3686)$ events collected with the BESIII detector at the BEPCII storage ring. The mass and width of the $P$-wave charmonium spin-singlet state $h_c(^1P_1)$ are determined by simultaneously fitting distributions of the $π^0$ recoil mass for 16 exclusive $η_c$ decay modes. The results, $M(\hc) = 3525.31 \pm 0.11 {\rm (stat.)} \pm 0.14 {\rm (syst.)}$\,MeV/$c^2$ and $Γ(\hc) = 0.70 \pm 0.28 \pm 0.22$\,MeV, are consistent with and more precise than previous measurements. We also determine the branching ratios for the 16 exclusive $η_c$ decay modes, five of which have not been measured previously. New measurements of the $η_c$ line-shape parameters in the $E1$ transition $h_c\toγη_c$ are made by selecting candidates in the $h_c$ signal sample and simultaneously fitting the hadronic mass spectra for the 16 $η_c$ decay channels. The resulting $η_c$ mass and width values are $M(η_c) = 2984.49 \pm 1.16 \pm 0.52$\,MeV/$c^2$ and $Γ(η_c) = 36.4 \pm 3.2 \pm 1.7$\,MeV.

hep-ex

Search for the $η_c(2S)/h_c\to p\bar{p}$ decays and measurements of the $χ_{cJ}\to p\bar{p}$ branching fractions

Using a sample of $1.06\times10^{8}~ψ(3686)$ events collected with the BESIII detector at BEPCII, the decays $η_{c}(2S)\to p\bar{p}$ and $h_{c}\to p\bar{p}$ are searched for, where $η_c(2S)$ and $h_c$ are reconstructed in the decay chains $ψ(3686)\toγη_{c}(2S)$, $η_{c}(2S)\to p\bar{p}$ and $ψ(3686)\toπ^{0}h_{c}$, $h_{c}\to p\bar{p}$, respectively. No significant signals are observed. The upper limits of the product branching fractions are determined to be $\mathcal{B}(ψ(3686)\toγη_c(2S))\times\mathcal{B}(η_{c}(2S)\to p\bar{p})<1.4\times10^{-6}$ and $\mathcal{B}(ψ(3686)\toπ^0h_c)\times\mathcal{B}(h_{c}\to p\bar{p})<1.3\times10^{-7}$ at the 90% C.L.. The branching fractions for $χ_{cJ}\to p\bar{p}$ $(J=0,~1,~2)$ are also measured to be $(24.5\pm0.8\pm1.3,~8.6\pm0.5\pm0.5,~8.4\pm0.5\pm0.5)\times10^{-5}$, which are the world's most precise measurements.

hep-ex

Study of e$^+$e$^-$ $\rightarrow \text{p} \overline{\text{p}}π^0$ in the Vicinity of the $ψ\text{(3770)}$

The process $e^+e^-\rightarrow p\overline{p}π^0$ has been studied by analyzing data collected at $\sqrt{s}=3.773$ GeV, at $\sqrt{s}=3.650$ GeV, and during a $ψ(3770)$ line shape scan with the BESIII detector at the BEPCII collider. The Born cross section of $p \overline{p} π^0$ in the vicinity of the $ψ(3770)$ is measured and the Born cross section of $ψ(3770)\rightarrow p \overline{p} π^0$ is extracted considering interference between resonant and continuum production amplitudes. Two solutions with the same probability and a significance of 1.5$σ$ are found, and the Born cross section of $ψ(3770)\rightarrow p \overline{p} π^0$ is determined to be less than 0.22 pb at 90% confidence level and $33.8\pm1.8\pm2.1$ pb, respectively. Using the estimated cross section and a constant decay amplitude approximation, the cross section $σ(p\overline{p} \rightarrow ψ(3770) π^0)$ is calculated for the kinematic situation of the planned $\overline{\text{P}}\text{ANDA}$ experiment. The maximum cross section corresponding to the two solutions is expected to be less than $0.79$ nb at 90% confidence level and $122\pm10$ nb at a center of mass energy of 5.26 GeV.

hep-ex

Study of $e^+e^- \rightarrow p\bar{p}$ in the vicinity of $ψ(3770)$

Using 2917 $\rm{pb}^{-1}$ of data accumulated at 3.773~$\rm{GeV}$, 44.5~$\rm{pb}^{-1}$ of data accumulated at 3.65~$\rm{GeV}$ and data accumulated during a $ψ(3770)$ line-shape scan with the BESIII detector, the reaction $e^+e^-\rightarrow p\bar{p}$ is studied considering a possible interference between resonant and continuum amplitudes. The cross section of $e^+e^-\rightarrowψ(3770)\rightarrow p\bar{p}$, $σ(e^+e^-\rightarrowψ(3770)\rightarrow p\bar{p})$, is found to have two solutions, determined to be ($0.059\pm0.032\pm0.012$) pb with the phase angle $ϕ= (255.8\pm37.9\pm4.8)^\circ$ ($<$0.11 pb at the 90% confidence level), or $σ(e^+e^-\rightarrowψ(3770)\rightarrow p\bar{p}) = (2.57\pm0.12\pm0.12$) pb with $ϕ= (266.9\pm6.1\pm0.9)^\circ$ both of which agree with a destructive interference. Using the obtained cross section of $ψ(3770)\rightarrow p\bar{p}$, the cross section of $p\bar{p}\rightarrow ψ(3770)$, which is useful information for the future PANDA experiment, is estimated to be either ($9.8\pm5.7$) nb ($<17.2$ nb at 90% C.L.) or $(425.6\pm42.9)$ nb.

hep-ex

Observation of $χ_{c1}$ decays into vector meson pairs $ϕϕ$, $ωω$, and $ωϕ$

Decays of $χ_{c1}$ to vector meson pairs $ϕϕ$, $ωω$ and $ωϕ$ are observed for the first time using $(106\pm4)\times 10^6$ $\psip$ events accumulated at the BESIII detector at the BEPCII $e^+e^-$ collider. The branching fractions are measured to be $(4.4\pm 0.3\pm 0.5)\times 10^{-4}$, $(6.0\pm 0.3\pm 0.7)\times 10^{-4}$, and $(2.2\pm 0.6\pm 0.2)\times 10^{-5}$, for $χ_{c1}\to ϕϕ$, $ωω$, and $ωϕ$, respectively. The observation of $χ_{c1}$ decays into a pair of vector mesons $ϕϕ$, $ωω$ and $ωϕ$ indicates that the hadron helicity selection rule is significantly violated in $χ_{cJ}$ decays. In addition, the measurement of $χ_{cJ}\to ωϕ$ gives the rate of doubly OZI-suppressed decay. Branching fractions for $χ_{c0}$ and $χ_{c2}$ decays into other vector meson pairs are also measured with improved precision.

hep-ex

Measurement of $χ_{cJ}$ decaying into $η^{\prime}K^+K^-$

Using $(106.41\pm 0.86) \times 10^{6}$ $ψ(3686)$ events collected with the BESIII detector at BEPCII, we study for the first time the decay $χ_{cJ}\toη'K^+K^-$, where $η'\toγρ^{0}$ and $η'\toηπ^+π^-$. A partial wave analysis in the covariant tensor amplitude formalism is performed for the decay $χ_{c1}\toη'K^+K^-$. Intermediate processes $χ_{c1}\toη' f_0(980)$, $χ_{c1}\toη' f_0(1710)$, $χ_{c1}\toη' f_2'(1525)$ and $χ_{c1}\to K^*_0(1430)^{\pm}K^{\mp}$ ($K^*_0(1430)^{\pm}\toη' K^{\pm}$) are observed with statistical significances larger than 5$σ$, and their branching fractions are measured.

hep-ex

Precision Measurement of the Mass of the $τ$ Lepton

An energy scan near the $τ$ pair production threshold has been performed using the BESIII detector. About $24$ pb$^{-1}$ of data, distributed over four scan points, was collected. This analysis is based on $τ$ pair decays to $ee$, $eμ$, $eh$, $μμ$, $μh$, $hh$, $eρ$, $μρ$ and $πρ$ final states, where $h$ denotes a charged $π$ or $K$. The mass of the $τ$ lepton is measured from a maximum likelihood fit to the $τ$ pair production cross section data to be $m_τ = (1776.91\pm0.12 ^{+0.10}_{-0.13}$) MeV/$c^2$, which is currently the most precise value in a single measurement.

hep-ex

Search for the radiative transitions $ψ(3770)\toγη_c$ and $γη_c(2S)$

By using a 2.92 fb$^{-1}$ data sample taken at $\sqrt{s} = 3.773$ GeV with the BESIII detector operating at the BEPCII collider, we search for the radiative transitions $ψ(3770)\toγη_c$ and $γη_c(2S)$ through the hadronic decays $η_c(η_c(2S))\to K^0_SK^\pmπ^\mp$. No significant excess of signal events above background is observed. We set upper limits at a 90% confidence level for the product branching fractions to be $\mathcal{B}(ψ(3770)\toγη_c)\times \mathcal{B}(η_c\to K^0_SK^\pmπ^\mp) < 1.6\times10^{-5}$ and $\mathcal{B}(ψ(3770)\toγη_c(2S))\times \mathcal{B}(η_c(2S)\to K^0_SK^\pmπ^\mp) < 5.6\times10^{-6}$. Combining our result with world-average values of $\mathcal{B}(η_c(η_c(2S))\to K^0_SK^\pmπ^\mp)$, we find the branching fractions $\mathcal{B}(ψ(3770)\toγη_c) < 6.8\times10^{-4}$ and $\mathcal{B}(ψ(3770)\toγη_c(2S)) < 2.0\times10^{-3}$ at a 90% confidence level.

hep-ex

Measurement of the $D\to K^-π^+$ strong phase difference in $ψ(3770)\to D^0\overline{D}{}^0$

We study $D^0\overline{D}{}^0$ pairs produced in $e^+e^-$ collisions at $\sqrt{s}=3.773$ GeV using a data sample of 2.92 fb$^{-1}$ collected with the BESIII detector. We measure the asymmetry $\mathcal{A}^{CP}_{Kπ}$ of the branching fractions of $D \to K^-π^+$ in $CP$-odd and $CP$-even eigenstates to be $(12.7\pm1.3\pm0.7)\times10^{-2}$. $\mathcal{A}^{CP}_{Kπ}$ can be used to extract the strong phase difference $δ_{Kπ}$ between the doubly Cabibbo-suppressed process $\overline{D}{}^{0}\to K^-π^+$ and the Cabibbo-favored process $D^0\to K^- π^+$. Using world-average values of external parameters, we obtain $\cosδ_{Kπ} = 1.02\pm0.11\pm0.06\pm0.01$. Here, the first and second uncertainties are statistical and systematic, respectively, while the third uncertainty arises from the external parameters. This is the most precise measurement of $δ_{Kπ}$ to date.

hep-ex

Precision measurements of $B(D^+ \rightarrow μ^+ ν_μ)$, the pseudoscalar decay constant $f_{D^+}$, and the quark mixing matrix element $|V_{\rm cd}|$

We report a measurement of the branching fraction $B(D^+ \rightarrow μ^+ ν_μ) = [3.71 \pm 0.19 (\rm stat) \pm 0.06 (\rm sys)]\times 10^{-4}$ based on 2.92 ${\rm fb^{-1}}$ of data accumulated at $\sqrt{s}=3.773$ GeV with the BESIII detector at the BEPCII collider. This measurement, in conjunction with the Cabibbo-Kobayashi-Maskawa matrix element $|V_{\rm cd}|$ determined from a global Standard Model fit, implies a value for the weak decay constant $f_{D^+}=(203.2 \pm 5.3 \pm 1.8)$ MeV. Additionally, using this branching fraction measurement together with a Lattice QCD prediction for $f_{D^+}$, we find $|V_{\rm cd}|=0.2210\pm 0.0058 \pm 0.0047$. In either case, these are the most precise results for these quantities to date.

hep-ex