B. G. Pushpawela
A5062484757- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Atmospheric chemistry and aerosols
- Air Quality and Health Impacts
- Neutrino Physics Research
- Atmospheric aerosols and clouds
- Particle Accelerators and Free-Electron Lasers
- Air Quality Monitoring and Forecasting
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Black Holes and Theoretical Physics
- Cosmology and Gravitation Theories
- Advanced Data Storage Technologies
- Medical Imaging Techniques and Applications
- Nuclear physics research studies
- Climate variability and models
- Atomic and Subatomic Physics Research
- Aerosol Filtration and Electrostatic Precipitation
- Chemical and Physical Studies
- Infection Control and Ventilation
- COVID-19 impact on air quality
- Superconducting Materials and Applications
- Hydrology and Drought Analysis
- Transboundary Water Resource Management
University of Alabama in Huntsville
2023-2024
California Institute of Technology
2021-2024
University of Cincinnati
2013-2022
University of Alabama
2022
Queensland University of Technology
2016-2018
Istituto Nazionale di Fisica Nucleare, Sezione di Bari
2018
University of the Basque Country
2018
Laboratoire d’Annecy de Physique des Particules
2018
Institut National de Physique Nucléaire et de Physique des Particules
2018
Centre National de la Recherche Scientifique
2018
Dark sectors charged under a new Abelian interaction have recently received much attention in the context of dark matter models. These models introduce light mediator, so-called photon (A′), connecting sector to standard model. We present search for reaction e+e−→γA′, A′→e+e−, μ+μ− using 514 fb−1 data collected with BABAR detector. observe no statistically significant deviations from model predictions, and we set 90% confidence level upper limits on mixing strength between at 10−4−10−3...
Many models of physics beyond the Standard Model predict existence new Abelian forces with gauge bosons mediating interactions between "dark sectors" and Model. We report a search for dark boson Z' coupling only to second third generations leptons in reaction e+e- -> mu+mu- Z', using 514 fb-1 data collected by BABAR experiment. No significant signal is observed masses range 0.212 - 10 GeV. Limits on parameter g' as low 7x10^-4 are derived, leading improvements bounds compared those...
We present a measurement of the total branching fraction flavor-changing neutral-current process B->Xsl+l-, along with partial fractions in bins dilepton and hadronic system (Xs) mass, using sample 471x10^6 Upsilon(4S)->BBbar events recorded BaBar detector at PEP-II e+e- collider. B mesons are reconstructed by combining pair, either or mu+mu-, 10 different Xs final states containing exactly one charged neutral kaon, two fewer pions, most pi0. Using sum over these exclusive modes as basis for...
We present measurements of Collins asymmetries in the inclusive process ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\pi}X$, where $\ensuremath{\pi}$ stands for charged pions, at a center-of-mass energy 10.6 GeV. use data sample $468\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected by BABAR experiment PEP-II $B$ factory SLAC, and consider pairs pions produced opposite hemispheres hadronic events. observe clear distributions azimuthal angles two...
A precise measurement of the cross section for process e+e−→K+K−(γ) from threshold to an energy 5 GeV is obtained with initial-state radiation (ISR) method using 232 fb−1 data collected BABAR detector at e+e− center-of-mass energies near 10.6 GeV. The uses effective ISR luminosity determined e+e−→μ+μ−(γ)γISR same set. corresponding lowest-order contribution hadronic vacuum polarization term in muon magnetic anomaly found be aμKK,LO=(22.93±0.18stat±0.22syst)×10−10. charged kaon form factor...
The ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}p\overline{p}$ cross section and the proton magnetic form factor have been measured in center-of-mass energy range from 3.0 to 6.5 GeV using initial-state radiation technique with an undetected photon. This is first measurement of at energies higher than 4.5 GeV. analysis based on $469\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ integrated luminosity collected BABAR detector PEP-II collider ${e}^{+}{e}^{\ensuremath{-}}$ near 10.6...
We search for the rare flavor-changing neutral current process $B^{+}\rightarrow K^{+}τ^{+}τ^{-}$ using data from BABAR experiment. The sample, collected at center-of-mass energy of $Υ{(4S)}$ resonance, corresponds to a total integrated luminosity 424 fb$^{-1}$ and 471 million $B\overline{B}$ pairs. reconstruct one $B$ meson, produced in $Υ{(4S)}\rightarrow B^{+} B^{-}$ decay, many hadronic decay modes activity compatible with K^{+} τ^{+}τ^{-}$ rest event. Each $τ$ lepton is required...
We study the lepton forward-backward asymmetry ${\mathcal{A}}_{FB}$ and longitudinal ${K}^{*}$ polarization ${F}_{L}$, as well an observable ${P}_{2}$ derived from them, in rare decays $B\ensuremath{\rightarrow}{K}^{*}{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$, where ${\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ is either ${e}^{+}{e}^{\ensuremath{-}}$ or ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$, using full sample of 471 million...
Air quality in urban areas is deteriorating over time with the increased pollutant distribution levels mainly caused due to anthropogenic activities. In addition, these may relate changing meteorological conditions. However, relationships were not researched in-depth context of Sri Lanka, a country significant impact on climate change. The main objective this study was provide broader perspective seasonal variation tiny particles air (PM2.5 and PM10), nitrogen dioxide (NO2), carbon monoxide...
We study the processes $e^+ e^-\to K_S^0 K_L^0 \gamma$, $K_S^0 \pi^+\pi^-\gamma$, and K^+K^-\gamma$, where photon is radiated from initial state, providing cross section measurements for hadronic states over a continuum of center-of-mass energies. The results are based on 469 fb$^{-1}$ data collected with BaBar detector at SLAC. observe $\phi(1020)$ resonance in K_L^0$ final state measure product its electronic width branching fraction about 3% uncertainty. present measurement $ energy range...
In response to the COVID-19 pandemic in early 2020, Sri Lanka underwent a nationwide lockdown that limited motor vehicle movement, industrial operations, and human activities. This study analyzes impact of on carbon monoxide (CO), ozone (O3), nitrogen dioxide (NO2), sulfur (SO2), particulate matter (PM10, PM2.5) concentrations two urban cities (Colombo Kandy) Lanka, by comparison data from period (March May 2020) with its analogous 2019 2021. The results showed percentage change daytime...
We study the process $e^+e^- \to \pi^+\pi^-\eta \gamma$, where photon is radiated from initial state. About 8000 fully reconstructed events of this are selected BaBar data sample with an integrated luminosity 469~fb$^{-1}$. Using $\pi^+\pi^-\eta$ invariant mass spectrum we measure \pi^+\pi^-\eta$ cross section in $e^+e^-$ center-of-mass energy range 1.15 to 3.5 GeV. The well described by Vector-Meson Dominance model four $\rho$-like states. observe $49\pm9$ $J/\psi$ decay $\pi^+\pi^-\eta$,...
Based on a sample of 500 million ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}c\overline{c}$ events recorded by the BABAR detector at c.m. energies close to 10.6 GeV, we report study decay ${D}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{e}^{+}{\ensuremath{\nu}}_{e}$. We measure ratio branching fractions,...
We study the processes $\gamma \gamma \to \eta_c \eta' K^+ K^-$, $\eta' \pi^+ \pi^-$, and $\eta \pi^-$ using a data sample of 519 $fb^{-1}$ recorded with BaBar detector operating at SLAC PEP-II asymmetric-energy $e^+e^-$ collider center-of-mass energies near $\Upsilon(nS)$ ($n = 2,3,4$) resonances. This is first observation decay $\eta_c K^-$ we measure branching fraction $\Gamma(\eta_c K^-)/(\Gamma(\eta_c \pi^-)=0.644\pm 0.039_{\rm stat}\pm 0.032_{\rm sys}$. Significant interference...
We present Dalitz plot analyses for the decays of $B$ mesons to ${D}^{\ensuremath{-}}{D}^{0}{K}^{+}$ and ${\overline{D}}^{0}{D}^{0}{K}^{+}$. report observation ${D}_{s1}^{*}(2700{)}^{+}$ resonance in these two channels obtain measurements mass $M({D}_{s1}^{*}(2700{)}^{+})={2699}_{\ensuremath{-}7}^{+14}\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ width $\mathrm{\ensuremath{\Gamma}}({D}_{s1}^{*}(2700{)}^{+})={127}_{\ensuremath{-}19}^{+24}\text{ }\mathrm{MeV}$, including statistical systematic...
Abstract. New particle formation (NPF) has been observed in many highly polluted environments of South East Asia, including Beijing, where the extent its contribution to intense haze events is still an open question. Estimated characteristics NPF events, such as their starting times and growth rates particles, are more accurate when detection range particles extends smaller sizes. In order understand very first steps formation, we used a neutral cluster air ion spectrometer (NAIS)...
We study the processes γγ→K+K−η and γγ→K+K−π0 using a data sample of 519 fb−1 recorded with BABAR detector operating at SLAC PEP-II asymmetric-energy e+e− collider center-of-mass energies near Υ(nS) (n=2,3,4) resonances. observe ηc→K+K−π0 ηc→K+K−η decays, measure their relative branching fraction, perform Dalitz plot analysis for each decay. K∗0(1430)→Kη decay its fraction to Kπ mode be R(K∗0(1430))=B(K∗0(1430)→Kη)B(K∗0(1430)→Kπ)=0.092±0.025+0.010−0.025. The results correspond first...
We present measurements of Collins asymmetries in the inclusive process $e^+e^- \rightarrow h_1 h_2 X$, $h_1h_2=KK,\, K\pi,\, \pi\pi$, at center-of-mass energy 10.6 GeV, using a data sample 468 fb$^{-1}$ collected by BaBar experiment PEP-II $B$ factory SLAC National Accelerator Center. Considering hadrons opposite thrust hemispheres hadronic events, we observe clear azimuthal ratio unlike- to like-sign, and all charged $h_1 h_2$ pairs, which increase with hadron energies. The $K\pi$ are...
The decay ${\ensuremath{\tau}}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{K}_{S}{\ensuremath{\nu}}_{\ensuremath{\tau}}$ has been studied using $430\ifmmode\times\else\texttimes\fi{}{10}^{6}$ ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\tau}}^{+}{\ensuremath{\tau}}^{\ensuremath{-}}$ events produced at a center-of-mass energy around 10.6 GeV the PEP-II collider and with BABAR detector. mass spectrum of ${K}^{\ensuremath{-}}{K}_{S}$ system measured...
We study the processes $e^+ e^-\to K^0_S K^0_L\pi^0\gamma$, $K^0_S K^0_L\eta\gamma$, and K^0_L\pi^0\pi^0\gamma$, where photon is radiated from initial state, providing cross section measurements for hadronic final states over a continuum of center-of-mass energies. The results are based on 469~$fb^{-1}$ data collected at or near $\Upsilon(4S)$~ resonance with BaBar detector SLAC. present first K^0_L\pi^0$, K^0_L\eta$, K^0_L\pi^0\pi^0$ sections up to energy 4~GeV, their intermediate...
Axionlike particles (ALPs) are predicted in many extensions of the standard model, and their masses can naturally be well below electroweak scale. In presence couplings to bosons, these could emitted flavor-changing B meson decays. We report herein a search for an ALP, a, reaction B^{±}→K^{±}a, a→γγ using data collected by BABAR experiment at SLAC. No significant signal is observed, 90% confidence level upper limits on ALP coupling bosons derived as function mass, improving current...